JP6835766B2 - Stacked battery - Google Patents

Description

The present invention relates to a laminated battery.

For example, as proposed in Patent Document 1, a laminated battery in which positive electrode plates and negative electrode plates are alternately laminated is widely used. As an example of the laminated battery, a lithium ion secondary battery can be exemplified. One of the features of the lithium-ion secondary battery is that it has a large capacity as compared with other types of stacked batteries. Lithium-ion secondary batteries having such characteristics are expected to be further spread in various applications such as in-vehicle applications and stationary housing applications.

In a laminated battery, for example, ions move between a positive electrode plate and a negative electrode plate via an electrolytic solution to charge and discharge the battery. For example, in the case of a lithium ion secondary battery, charging is performed by moving lithium ions in the electrolytic solution from the positive electrode to the negative electrode, and discharging is performed by moving from the negative electrode to the positive electrode. The electrolytic solution is held on an insulating sheet (separator) provided between the positive electrode plate and the negative electrode plate.

In the laminated battery shown in Patent Document 1, a zigzag-shaped insulating sheet is provided between each positive electrode plate and the negative electrode plate. That is, the positive electrode plate and the negative electrode plate are arranged between the folded surfaces of the insulating sheet. Such an insulating sheet can be manufactured more easily than arranging one insulating sheet between the positive electrode plate and the negative electrode plate. In the laminated battery of Patent Document 1, in order to increase the battery capacity (energy density) per unit volume, that is, to reduce the volume, the insulating sheet should not form a gap between the positive electrode plate and the negative electrode plate. It is folded back.

Japanese Unexamined Patent Publication No. 2014-165055

By the way, if there is a portion of the insulating sheet in which the electrolytic solution is not held, the positive electrode plate and the negative electrode plate facing the portion do not contribute to charging and discharging, which is inefficient when charging and discharging. In particular, when the insulating sheet is folded in a zigzag manner as in Patent Document 1, it becomes difficult to hold the electrolytic solution in the vicinity of the folded portion. Therefore, the electrolytic solution is not sufficiently supplied to the vicinity of the ends of the positive electrode plate and the negative electrode plate facing the folded-back portion of the insulating sheet, and it becomes difficult to contribute to charging and discharging. Therefore, the charging and discharging capacities of the laminated battery are reduced.

The laminated battery usually includes dozens of positive electrode plates and dozens of negative electrode plates. If the vicinity of the ends of the positive electrode plate and the negative electrode plate does not contribute to charging and discharging, the charging and discharging efficiency of the entire laminated battery can be significantly deteriorated.

The present invention has been made in consideration of such points, and an object of the present invention is to improve the efficiency of charging and discharging in a laminated battery having a zigzag-shaped insulating sheet.

The laminated battery of the present invention
Multiple electrode plates stacked in the stacking direction and
An insulating sheet that is alternately folded back in a width direction non-parallel to the stacking direction and arranged between two electrode plates adjacent to each other in the stacking direction is provided.
A gap is provided between the folded-back portion of the insulating sheet and the end portion of the electrode plate facing the folded-back portion in the width direction.

In the laminated battery of the present invention, unevenness may be formed in the folded-back portion.

In the laminated battery of the present invention, the length between the folded-back portion along the width direction and the end portion of the electrode plate facing the folded-back portion is five times or more the thickness of the electrode plate. You may.

In the laminated battery of the present invention, the length between the folded portion along the width direction and the end portion of the electrode plate facing the folded portion is 10 times or more the thickness of the electrode plate. You may.

In the laminated battery of the present invention, the insulating sheet may have a base material layer formed of a porous body.

In the laminated battery of the present invention, the insulating sheet may have a functional layer containing an inorganic material.

In the laminated battery of the present invention
The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The folded portion includes a first folded portion that folds the insulating sheet on one side in the width direction, and a second folded portion that folds the insulating sheet on the other side in the width direction.
Even if the first folded portion is located on one side in the width direction of the second electrode plate adjacent to the first electrode plate facing the first folded portion with respect to one end in the width direction. Good.

In the laminated battery of the present invention
The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The folded portion includes a first folded portion that folds the insulating sheet on one side in the width direction, and a second folded portion that folds the insulating sheet on the other side in the width direction.
The length in the width direction between the first folded portion and the end on one side in the width direction of the second electrode plate adjacent to the first electrode plate facing the first folded portion is the second. It may be shorter than the length in the width direction between the folded portion and the other end portion in the width direction of the second electrode plate facing the second folded portion.

In the laminated battery of the present invention
The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The insulating sheet has a base material layer and a functional layer laminated on the base material layer and having a higher porosity than the base material layer.
The side of the insulating sheet provided with the base material layer may face the first electrode plate, and the side provided with the functional layer may face the second electrode plate.

In the laminated battery of the present invention
The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The insulating sheet has a base material layer and a functional layer laminated on the base material layer and having heat resistance higher than that of the base material layer.
The side of the insulating sheet provided with the base material layer may face the second electrode plate, and the side provided with the functional layer may face the first electrode plate.

In the laminated battery of the present invention, the first electrode plate may be a positive electrode plate, and the second electrode plate may be a negative electrode plate.

The laminated battery of the present invention
Further provided with an exterior body for accommodating the electrode plate and the insulating sheet,
The folded portion may be in contact with the exterior body.

The laminated battery of the present invention may contain 20 or more of the electrode plates in total.

According to the present invention, in a laminated battery having a zigzag-shaped insulating sheet, it is possible to suppress a decrease in charge and discharge capacities.

FIG. 1 is a diagram for explaining an embodiment of the laminated battery of the present invention, and is a perspective view showing the laminated battery. FIG. 2 is a perspective view showing the inside of the laminated battery of FIG. 1 with the exterior body, the insulating sheet, and the like removed. FIG. 3 is a plan view showing a membrane electrode assembly included in the laminated battery of FIG. FIG. 4 is a diagram showing a cross section taken along the line IV-IV of FIG. FIG. 5 is a diagram showing a part of a cross section taken along the line VV of FIG. FIG. 6 is an enlarged view of one side of the electrode plate and the insulating sheet of the laminated battery shown in FIG. 5 in the width direction. FIG. 7 is an enlarged view of the other side of the electrode plate and the insulating sheet of the laminated battery shown in FIG. 5 in the width direction. FIG. 8 is an enlarged view of the inside of the VIII frame of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, etc. are appropriately changed from those of the actual product and exaggerated for the sake of ease of understanding.

1 to 8 are views for explaining an embodiment of a laminated electrode according to the present invention. FIG. 1 is a perspective view showing a specific example of a laminated battery. As shown in FIG. 1, the laminated battery 1 is connected to the exterior body 3, the membrane electrode assembly 5 housed in the exterior body 3, and the membrane electrode assembly 5, and is connected from the inside to the outside of the exterior body 3. It has a tab 4 that extends out. As shown in FIG. 2, the membrane electrode assembly 5 has a first electrode plate 10 and a second electrode plate 20 that are alternately laminated. In the example shown in FIG. 1, the laminated battery 1 has an overall flat shape and spreads in the first direction d1 which is the lateral direction and the second direction d2 which is the longitudinal direction.

Hereinafter, an example in which the laminated battery 1 constitutes a lithium ion secondary battery will be described. In this example, the first electrode plate 10 constitutes the positive electrode plate 10X, and the second electrode plate 20 constitutes the negative electrode plate 20Y. However, as can be understood from the description of the action and effect described below, the embodiment described here is not limited to the lithium ion secondary battery, and the first electrode plate 10 and the second electrode plate are not limited. It can be widely applied to a laminated battery 1 in which 20 are alternately laminated.

The exterior body 3 is a packaging material for sealing the membrane electrode assembly 5. The exterior body 3 forms an accommodation space for accommodating the membrane electrode assembly 5. The exterior body 3 seals the membrane electrode assembly 5 and the electrolytic solution inside. The exterior body 3 has, for example, two base materials and an adhesive layer arranged between the two base materials. The base material preferably has high gas barrier properties and molding processability. Aluminum foil or stainless steel foil can be used as such a base material. On the other hand, the adhesive layer functions as a sealing layer for joining the two base materials. The adhesive layer preferably has insulating properties, chemical resistance, thermoplasticity, etc., in addition to adhesiveness. As such an adhesive layer, for example, polypropylene, modified polypropylene, low density polypropylene, ionomer, ethylene / vinyl acetate and the like can be used. The thickness of the exterior body 3 is, for example, 100 μm or more and 300 μm or less.

The tab 4 functions as a terminal in the laminated battery 1. A cross section along line IV-IV of FIG. 1 is shown in FIG. As shown in FIGS. 2 and 4, one tab 4 (one side of the second direction d2) is electrically connected to the positive electrode plate 10X (first electrode plate 10) of the membrane electrode assembly 5. Similarly, the tab 4 on the other side (the other side of the second direction d2) is electrically connected to the negative electrode plate 20Y (second electrode plate 20) of the membrane electrode assembly 5. The tab 4 can be formed using aluminum, nickel, nickel-plated copper or the like. As shown in FIG. 1, the pair of tabs extend from the inside of the exterior body 3 to the outside of the exterior body 3. As shown in FIG. 4, the exterior body 3 and the tab 4 are sealed in a region where the tab 4 extends.

Next, the membrane electrode assembly 5 will be described. As shown in FIGS. 3 to 5, the membrane electrode assembly 5 has a positive electrode plate 10X (first electrode plate 10), a negative electrode plate 20Y (second electrode plate 20), and an insulating sheet 30. There is. As shown in FIG. 4, the positive electrode plate 10X and the negative electrode plate 20Y are alternately laminated along the stacking direction dL (vertical direction in FIG. 4). The membrane electrode assembly 5 includes, for example, 20 or more positive electrode plates 10X and negative electrode plates 20Y in total. The membrane electrode assembly 5 has an overall flat shape, is thin in the stacking direction dL, and spreads in a direction non-parallel to the stacking direction dL. In the example shown in FIG. 3, the membrane electrode assembly 5 extends in the first direction d1 and the second direction d2 orthogonal to the stacking direction dL. The thickness of the membrane electrode assembly 5, that is, the length in the stacking direction dL is, for example, 4 mm or more and 20 mm or less.

In the non-limiting example shown, the positive electrode plate 10X and the negative electrode plate 20Y are plate-shaped electrodes having a rectangular outer contour. The first direction d1 that is non-parallel to the stacking direction dL is the lateral direction (width direction) of the positive electrode plate 10X and the negative electrode plate 20Y, and the second direction d2 that is non-parallel to both the stacking direction dL and the first direction d1 is. , The positive direction plate 10X and the negative electrode plate 20Y in the longitudinal direction. In the illustrated example, the stacking direction dL, the first direction d1 and the second direction d2 are orthogonal to each other. As shown in FIGS. 2 to 4, the positive electrode plate 10X and the negative electrode plate 20Y are arranged so as to be offset in the second direction d2. More specifically, the plurality of positive electrode plates 10X are arranged closer to one side in the second direction d2, and the plurality of negative electrode plates 20Y are arranged closer to the other side in the second direction d2. The positive electrode plate 10X and the negative electrode plate 20Y overlap each other in the stacking direction dL at the center in the second direction d2. FIG. 5 shows a part of a cross section of the laminated battery 1 along the VV line of FIG. As shown in FIG. 5, the length of the negative electrode plate 20Y (second electrode plate 20) along the first direction d1 (width direction) is the first direction of the positive electrode plate 10X (first electrode plate 10). It is longer than the length along d1. In the illustrated example, the negative electrode plate 20Y extends from the positive electrode plate 10X to one side and the other side of the first direction d1. The thickness of the positive electrode plate 10X and the negative electrode plate 20Y, that is, the length in the stacking direction dL is, for example, 4 mm or more and 20 mm or less, and the length (width) in the lateral direction, that is, along the first direction d1, is, for example, 80 mm or more. It is 250 mm or less, and the length in the longitudinal direction, that is, along the second direction d2 is, for example, 250 mm or more and 500 mm or less.

As shown in FIG. 4, the positive electrode plate 10X (first electrode plate 10) has a positive electrode current collector 11X (first electrode current collector 11) and a positive electrode activity provided on the positive electrode current collector 11X. It has a material layer 12X (first electrode active material layer 12). In the lithium ion secondary battery, the positive electrode plate 10X emits lithium ions when discharged and occludes lithium ions when charged.

As shown in FIGS. 3 and 4, the positive electrode current collector 11X has a first surface 11a and a second surface 11b facing each other as main surfaces. The positive electrode active material layer 12X is formed on both surfaces of the first surface 11a and the second surface 11b of the positive electrode current collector 11X. The plurality of positive electrode plates 10X included in the laminated battery 1 have a pair of positive electrode active material layers 12X provided on both sides of the positive electrode current collector 11X, and may be configured to be identical to each other.

The positive electrode current collector 11X and the positive electrode active material layer 12X can be produced by various manufacturing methods using various materials that can be applied to the laminated battery 1 (lithium ion secondary battery). As an example, the positive electrode current collector 11X can be formed of aluminum foil. The positive electrode active material layer 12X contains, for example, a positive electrode active material, a conductive auxiliary agent, and a binder serving as a binder. The positive electrode active material layer 12X is produced by coating a positive electrode slurry formed by dispersing a positive electrode active material, a conductive auxiliary agent and a binder in a solvent on a material forming the positive electrode current collector 11X and solidifying the positive electrode active material layer 12X. Can be done. As the positive electrode active material, for example, a _{lithium metallic acid compound represented by the general formula LiM x} O _y (where M is a metal and x and y are composition ratios of metal M and oxygen O) is used. Specific examples of the lithium metallic acid compound include lithium cobalt oxide, lithium nickel oxide, lithium manganate and the like. As the conductive auxiliary agent, acetylene black or the like can be used. As the binder, polyvinylidene fluoride or the like can be used.

As shown in FIG. 3, the positive electrode current collector 11X (first electrode current collector 11) has a first end region a1 and a first electrode region b1. The positive electrode active material layer 12X (first electrode active material layer 12) is arranged only in the first electrode region b1 of the positive electrode current collector 11X. The first end region a1 and the first electrode region b1 are arranged in the second direction d2. The first end region a1 is located outside the first electrode region b1 in the second direction d2 (left side in FIG. 3). As shown in FIG. 4, the plurality of positive electrode current collectors 11X are joined by resistance welding, ultrasonic welding, tape bonding, fusion, etc. in the first end region a1, and are electrically connected. .. In the illustrated example, one tab 4 is electrically connected to the positive electrode current collector 11X in the first end region a1. The tab 4 extends from the membrane electrode assembly 5 in the second direction d2. On the other hand, as shown in FIG. 3, the first electrode region b1 is located in the region of the negative electrode plate 20Y facing the negative electrode active material layer 22Y described later. Then, as shown in FIG. 5, the width of the positive electrode plate 10X along the first direction d1 is narrower than the width of the negative electrode plate 20Y along the first direction d1. By such an arrangement of the first electrode region b1, it is possible to prevent the precipitation of lithium from the positive electrode active material layer 12X.

Next, the negative electrode plate 20Y (second electrode plate 20) will be described. The negative electrode plate 20Y (second electrode plate 20) includes a negative electrode current collector 21Y (second electrode current collector 21) and a negative electrode active material layer 22Y (second electrode active material layer) provided on the negative electrode current collector 21Y. 22) and. In the lithium ion secondary battery, the negative electrode plate 20Y occludes lithium ions during discharging and releases lithium ions during charging.

The negative electrode current collector 21Y has a first surface 21a and a second surface 21b facing each other as main surfaces. The negative electrode active material layer 22Y is formed on both surfaces of the first surface 21a and the second surface 21b of the negative electrode current collector 21Y. The plurality of negative electrode plates 20Y included in the laminated battery 1 have a pair of negative electrode active material layers 22Y provided on both sides of the negative electrode current collector 21Y, and may be configured to be the same as each other.

The negative electrode current collector 21Y and the negative electrode active material layer 22Y can be produced by various manufacturing methods using various materials that can be applied to the laminated battery 1 (lithium ion secondary battery). As an example, the negative electrode current collector 21Y is formed of, for example, a copper foil. The negative electrode active material layer 22Y contains, for example, a negative electrode active material made of a carbon material and a binder that functions as a binder. The negative electrode active material layer 22Y forms a negative electrode current collector 21Y, for example, a slurry for a negative electrode formed by dispersing a negative electrode active material made of carbon powder, graphite powder, or the like and a binder such as polyvinylidene fluoride in a solvent. It can be produced by coating on a material and solidifying it.

As described above, the first electrode region b1 of the positive electrode plate 10X is located inside the region of the negative electrode plate 20Y facing the second electrode region b2 (see FIG. 3). That is, the second electrode region b2 extends to a region including a region of the positive electrode plate 10X facing the positive electrode active material layer 12X. As shown in FIG. 5, the width of the negative electrode plate 20Y along the first direction d1 is wider than the width of the positive electrode plate 10X along the first direction d1. In particular, the one-sided end portion 20a of the negative electrode plate 20Y in the first direction d1 is located on one side in the first direction d1 of the positive electrode plate 10X with respect to the one-sided end portion 10a in the first direction d1, and the negative electrode plate. The other side end portion 20b in the first direction d1 of 20Y is located on the other side in the first direction d1 than the other side end portion 10b in the first direction d1 of the positive electrode plate 10X.

Next, the insulating sheet 30 will be described. As shown in FIGS. 4 to 7, the insulating sheet 30 is placed between two positive electrode plates 10X (first electrode plate 10) and a negative electrode plate 20Y (second electrode plate 20) adjacent to each other in the stacking direction dL. Have been placed. The insulating sheet 30 insulates two adjacent positive electrode plates 10X and a negative electrode plate 20Y, and holds an electrolytic solution sealed together with the membrane electrode assembly 5 in the exterior body 3 to form the positive electrode plate 10X and the negative electrode plate 20Y. Supply the electrolyte. As shown in FIG. 4, the insulating sheet 30 is alternately folded back in the first direction d1 (width direction) non-parallel to the stacking direction dL. That is, the insulating sheet 30 has a zigzag shape. One surface of the pair of main surfaces of the insulating sheet 30 facing each other comes to face the positive electrode plate 10X, and the other surface of the pair of main surfaces faces the negative electrode plate 20Y. ..

In the illustrated example, one insulating sheet 30 has a zigzag shape and is arranged between the positive electrode plate 10X and the negative electrode plate 20Y. However, not limited to this example, the laminated battery 1 may have a plurality of insulating sheets 30 having a zigzag shape. The thickness of the insulating sheet 30 is, for example, 8 μm or more and 30 μm or less.

In the example shown in FIG. 5, the insulating sheet 30 includes an insulating portion 31, an extending portion 32, and folded portions 33 and 34. The folded portions 33 and 34 include a first folded portion 33 that folds the insulating sheet 30 on one side in the first direction d1, and a second folded portion 34 that folds the insulating sheet 30 on the other side in the first direction d1. There is.

The insulating portion 31 is a part of the insulating sheet 30 arranged between the positive electrode plate 10X and the negative electrode plate 20Y, and prevents a short circuit between the positive electrode plate 10X and the negative electrode plate 20Y. That is, in the stacking direction dL, the insulating portion 31 is arranged between each positive electrode plate 10X and the negative electrode plate 20Y. In other words, in the stacking direction dL, the positive electrode plate 10X, the insulating portion 31, the negative electrode plate 20Y, the insulating portion 31, the positive electrode plate 10X, and so on are laminated in this order. The insulating portion 31 is provided over the entire area of the portion facing the positive electrode plate 10X and the negative electrode plate 20Y in the stacking direction dL.

The extending portion 32 is a part of the insulating sheet 30 extending from the insulating portion 31 at a position where the ends of the positive electrode plate 10X and the negative electrode plate 20Y are in contact with each other in the first direction d1. More specifically, as shown in FIGS. 6 and 7 in which a part of one side and a part of the other side of the first direction d1 of the membrane electrode assembly 5 shown in FIG. 5 is enlarged, the extension portion 32 Is one side of the insulating sheet 30 in the first direction d1 from the one side end portion 10a which is the end portion of the positive electrode plate 10X on one side of the first direction d1 and the one side end portion 20a which is the end portion of the negative electrode plate 20Y. In the first direction d1 from the other side end portion 10b which is the end portion of the positive electrode plate 10X and the other side end portion 20b which is the end portion of the negative electrode plate 20Y on the other side of the first direction d1. This is the part located on the other side. The length of each extending portion 32 in the first direction d1 is, for example, 0.5 mm or more and 3.0 mm or less.

The first folded portion 33 and the second folded portion 34 are a part of the insulating sheet 30 for folding the insulating sheet 30 into a zigzag shape. As is well shown in FIG. 6, the first folded-back portion 33 is positioned so as to be offset from one side end portion 10a of the positive electrode plate 10X to one side in the first direction d1. The first folded-back portion 33 faces the first direction d1 with respect to the one-side end portion 10a of the positive electrode plate 10X. Similarly, as is well shown in FIG. 7, the second folded-back portion 34 is located offset from the other side end portion 20b of the negative electrode plate 20Y to the other side of the first direction d1. The second folded-back portion 34 faces the other side end portion 20b of the negative electrode plate 20Y in the first direction d1. Further, as shown in FIGS. 5 to 7, the first folded portion 33 and the second folded portion 34 may be in contact with the exterior body 3.

In the example shown in FIGS. 6 and 7, the insulating sheet 30 includes the extending portion 32, so that the positive electrode plate 10X facing the first folded portion 33 in the first folded portion 33 and the first direction d1. A gap 40 is provided between the one side end portion 10a and the one side end portion 10a. Similarly, when the insulating sheet 30 includes the extending portion 32, the second folded-back portion 34 and the other side end portion 20b of the negative electrode plate 20Y facing the second folded-back portion 34 in the first direction d1 are separated from each other. A gap 40 is provided. The length of the first folded-back portion 33 protruding from one side end 10a of the positive electrode plate 10X, which corresponds to the length obtained by adding the thickness of the insulating sheet at the first folded-back portion 33 to the size of the gap 40, that is, FIG. The length S1 between the first folded-back portion 33 and the one-side end portion 10a of the positive electrode plate 10X shown in the above is preferably 5 times or more the thickness T1 of the positive electrode plate 10X provided with the gap 40. More preferably, it is 10 times or more. Similarly, the protruding length of the second folded-back portion 34 from the other side end portion 20b of the negative electrode plate 20Y, which corresponds to the length obtained by adding the thickness of the insulating sheet at the second folded-back portion 34 to the size of the gap 40, that is, The length S2 between the second folded-back portion 34 and the other side end portion 20b of the negative electrode plate 20Y shown in FIG. 7 is 5 times or more the thickness T2 of the negative electrode plate 20Y provided with the gap 40. Is preferable, and 10 times or more is more preferable.

FIG. 8 is an enlarged view of the inside of the VIII frame shown in FIG. In FIG. 8, a part of the end portion of the insulating sheet 30 is enlarged and shown. In the example shown in FIG. 8, irregular irregularities are formed on the extending portion 32 and the second folded portion 34 of the insulating sheet 30. Although not shown, irregular irregularities are also formed on the first folded portion 33 as well.

The unevenness is formed by the wrinkled portion formed on the insulating sheet 30. Therefore, the unevenness appears as a convex portion 37 on one surface of the insulating sheet 30 and appears as a concave portion 38 on the other surface, and appears as a concave portion 38 on one surface of the insulating sheet 30 and on the other surface. A portion appearing as a convex portion 37 and a portion appearing in the above are included. Then, the extending portion 32 connected to the first folded portion 33 and the first folded portion 33 is formed with a convex portion 37 and a concave portion 38 on a surface facing the positive electrode plate 10X. Then, the convex portion 37 protrudes toward the positive electrode plate 10X, and the electrolytic solution held by the insulating sheet 30 can be stably supplied from the convex portion 37 to the positive electrode plate 10X. Similarly, the extending portion 32 connected to the second folded portion 34 and the second folded portion 34 is formed with a convex portion 37 and a concave portion 38 on a surface facing the negative electrode plate 20Y. Then, the convex portion 37 protrudes toward the negative electrode plate 20Y, and the electrolytic solution held by the insulating sheet 30 can be stably supplied from the convex portion 37 to the negative electrode plate 20Y.

The convex portion 37 and the concave portion 38 are formed in a linear shape, for example, and extend along the sheet surface of the insulating sheet 30. In the example shown in FIG. 8, the protrusions and recesses are arranged in the second direction d2. In this example, the convex portion 37 and the concave portion 38 extend in a direction non-parallel to the second direction d2, for example, the first direction d1.

In the example shown in FIG. 6, the first folded-back portion 33 is first of the positive electrode plate 10X facing the first folded-back portion 33 and one side end portion 20a of the negative electrode plate 20Y adjacent to the stacking direction dL. It is located on one side of direction d1. That is, the extending portion 32 of the insulating sheet 30 extends to one side in the first direction d1 from the positive electrode plate 10X and the negative electrode plate 20Y. As described above, since the negative electrode plate 20Y extends from the positive electrode plate 10X on both sides of the first direction d1, the second folded-back portion 34 has the second folded-back portion 34 as shown in FIG. It is located on the other side of the first direction d1 from the other side end portion 10b of the positive electrode plate 10X adjacent to the negative electrode plate 20Y facing the portion 34 and the stacking direction dL.

In the examples shown in FIGS. 6 and 7, the length of the extension portion 32 on one side and the length on the other side of the first direction d1 are equal. That is, the length S1 in the first direction d1 between the first folded portion 33 and the one side end portion 10a of the positive electrode plate 10X facing the first folded portion 33, the second folded portion 34, and the second folded portion 34. The length S2 in the first direction d1 between the negative electrode plate 20Y facing the portion 34 and the other side end portion 20b is equal. According to such a configuration, the region near the one side end portion 10a of the positive electrode plate 10X covered by the first folded portion 33 from the first direction and the negative electrode plate 20Y covered from the first direction by the second folded portion 34. It is possible to efficiently supply a sufficient amount of the electrolytic solution absorbed and retained by the insulating sheet 30 to both the region near the other end portion 20b.

Further, as described above, the negative electrode plates 20Y extend from the positive electrode plates 10X on both sides of the first direction d1. That is, the length S1 in the first direction d1 between the first folded portion 33 and the one side end portion 10a of the positive electrode plate 10X facing the first folded portion 33 is the first folded portion 33 and the first folded portion 33. It is longer than the length S3 in the first direction d1 between the positive electrode plate 10X facing the portion and the one side end portion 20a of the negative electrode plate 20Y adjacent to the stacking direction dL. Therefore, the length S3 in the first direction d1 between the first folded portion 33, the positive electrode plate 10X facing the first folded portion, and the one side end portion 20a of the negative electrode plate 20Y adjacent to the stacking direction dL is the first. The length S2 in the first direction d1 between the two folded portions 34 and the other side end portion 20b of the negative electrode plate 20Y facing the second folded portion 34 is shorter.

Further, as shown in FIGS. 4, 6 and 7, the insulating sheet 30 has a base material layer 35 and a functional layer 36 laminated on the base material layer 35. In the illustrated example, the side of the insulating sheet 30 provided with the base material layer 35 faces the positive electrode plate 10X, and the side provided with the functional layer 36 faces the negative electrode plate 20Y. However, not limited to the illustrated example, the side provided with the base material layer 35 may face the negative electrode plate 20Y, and the side provided with the functional layer 36 may face the positive electrode plate 10X.

The base material layer 35 is formed of, for example, a porous body. As such a porous body, a porous film made of a resin such as polyethylene or polypropylene can be exemplified. The thickness of the base material layer 35 is, for example, 5 μm or more and 30 μm or less.

The functional layer 36 contains, for example, an inorganic material. Such a functional layer 36 is, for example, a layer containing alumina particles. Since the functional layer 36 contains an inorganic material, the heat resistance of the functional layer 36 can be increased. The layer containing an inorganic material such as alumina particles has a smaller degree of heat shrinkage when heated than an organic material such as a resin forming the base material layer 35. That is, when the insulating sheet 30 includes the functional layer 36, the degree of heat shrinkage of the insulating sheet 30 is reduced. Thereby, for example, even when the battery is placed in a high temperature environment, it is possible to reduce the possibility that the positive and negative electrodes come into contact with each other due to the shrinkage of the insulating sheet 30 and a short circuit occurs. The thickness of the functional layer 36 is, for example, 2 μm or more and 15 μm or less.

By the way, in a laminated battery, an electrolytic solution held by an insulating sheet exists inside the exterior body, more specifically between the positive electrode plate and the negative electrode plate. Discharge and charge of the laminated battery are performed by the positive electrode plate and the negative electrode plate releasing and absorbing ions through the electrolytic solution. In other words, the positive electrode plate and the negative electrode plate facing the portion of the insulating sheet in which the electrolytic solution is held function as a battery by supplying the electrolytic solution from the insulating sheet. Conversely, the positive electrode plate and the negative electrode plate facing the portion of the insulating sheet where the electrolytic solution is not held cannot release and absorb ions because the electrolytic solution is not supplied, and exhibits the function as a battery. Can't. Therefore, it is desired that the insulating sheet retains the electrolytic solution in the entire portion facing the positive electrode plate and the negative electrode plate.

However, in the conventional laminated battery as shown in Patent Document 1, the insulating sheet is zigzag. As confirmed by the inventor of the present invention, due to the folding, the porosity ratio becomes low in the vicinity of the folded portion of the insulating sheet, and it becomes difficult to hold the electrolytic solution. Therefore, it is difficult for the electrolytic solution to be supplied to the vicinity of the ends of the positive electrode plate and the negative electrode plate facing the folded-back portion of the insulating sheet, and it is difficult to contribute to charging and discharging. For this reason, in a conventional laminated battery having a zigzag-shaped insulating sheet, the efficiency of charging and discharging may deteriorate.

On the other hand, according to the laminated battery of the present invention, even if the insulating sheet is folded in a zigzag manner, the insulating sheet can sufficiently hold the electrolytic solution in the portion facing the positive electrode plate and the negative electrode plate near the ends. It has become. Therefore, the electrolytic solution can be sufficiently supplied to the vicinity of the ends of the positive electrode plate and the negative electrode plate facing the folded-back portion of the insulating sheet, and the deterioration of the charging and discharging efficiency of the laminated battery can be suppressed. Can be done. In other words, the efficiency of charging and discharging the stacked battery can be improved. Hereinafter, in the laminated battery 1 of the present embodiment, a device that enables the electrolytic solution of the insulating sheet 30 to be held at the portions facing the ends of the positive electrode plate 10X and the negative electrode plate 20Y will be described.

In the laminated battery 1 of the present embodiment, between the first folded portion 33 of the insulating sheet 30 and the one side end portion 10a of the positive electrode plate 10X facing the first folded portion 33 in the first direction d1. Is provided with a gap 40. Similarly, a gap 40 is provided between the second folded-back portion 34 and the other side end portion 20b of the negative electrode plate 20Y facing the second folded-back portion 34 in the first direction d1. The insulating sheet 30 has an extending portion 32 which is a portion extending from one side end portion 10a of the positive electrode plate 10X to one side of the first direction d1 so that the gap 40 is provided. Further, the insulating sheet 30 has an extending portion 32 which is a portion extending from the other side end portion 20b of the negative electrode plate 20Y to the other side of the first direction d1 so that a gap 40 is provided. The extending portion 32 of the insulating sheet 30 can hold the electrolytic solution. Since the electrolytic solution can be held in the extending portion 32 which faces the vicinity of the one side end portion 10a of the positive electrode plate 10X and the vicinity of the other side end portion 20b of the negative electrode plate 20Y, one side of the positive electrode plate 10X can be held. The electrolytic solution can be supplied to the vicinity of the end portion 10a and the vicinity of the other side end portion 20b of the negative electrode plate 20Y. Therefore, the vicinity of the one side end portion 10a of the positive electrode plate 10X and the vicinity of the other side end portion 20b of the negative electrode plate 20Y can be contributed to charging and discharging, and the charging and discharging efficiency of the laminated battery can be improved. it can.

Preferably, the size of the gap 40 in the first direction d1, that is, the length S1 between the first folded-back portion 33 and the one-side end portion 10a of the positive electrode plate 10X is the positive electrode plate provided with the gap 40. It is 5 times or more, or 10 times or more, the thickness T1 of 10X. The length S2 between the second folded-back portion 34 and the other side end portion 20b of the negative electrode plate 20Y is 5 times or more or 10 times or more the thickness T2 of the negative electrode plate 20Y provided with the gap 40. .. In these cases, the extension portion 32 can be made large enough, so that the extension portion 32 can hold a sufficient amount of the electrolytic solution. That is, the portion of the insulating sheet 30 facing the vicinity of one side end 10a of the positive electrode plate 10X and the vicinity of the other side end 20b of the negative electrode plate 20Y can sufficiently hold the electrolytic solution, and one of the positive electrode plates 10X. The electrolytic solution can be sufficiently supplied to the vicinity of the side end portion 10a and the vicinity of the other side end portion 20b of the negative electrode plate 20Y. Therefore, the vicinity of the one side end portion 10a of the positive electrode plate 10X and the vicinity of the other side end portion 20b of the negative electrode plate 20Y can be sufficiently contributed to charging and discharging, and the charging and discharging efficiency of the laminated battery is further improved. Can be made to.

Further, the laminated battery 1 includes dozens of positive electrode plates 10X and dozens of negative electrode plates 20Y. If the vicinity of the ends of the positive electrode plate 10X and the negative electrode plate 20Y does not contribute to charging and discharging, the charging and discharging efficiency of the entire laminated battery 1 can be significantly deteriorated. Therefore, as the number of positive electrode plates 10X and negative electrode plates 20Y increases, the effect of improving the charging and discharging efficiency due to the provision of the gap 40 becomes more remarkable. Specifically, when the laminated battery 1 includes the positive electrode plate 10X and the negative electrode plate 20Y in total of 20 or more, the effect of improving the charging and discharging efficiency is remarkably exhibited.

Further, the first folded-back portion 33 is located in the first direction d1 rather than the one-sided end portion 20a in the first direction d1 of the negative electrode plate 20Y adjacent to the positive electrode plate 10X facing the first folded-back portion 33 and the stacking direction dL. It is located on one side. That is, the extending portion 32 extends from the negative electrode plate 20Y to one side in the first direction d1. Since the extending portion 32 facing the vicinity of the one side end portion 20a of the negative electrode plate 20Y holds the electrolytic solution, the electrolytic solution can be supplied to the vicinity of the one side end portion 20a of the negative electrode plate 20Y. Therefore, the vicinity of one side end portion 20a of the negative electrode plate 20Y can be contributed to charging and discharging, and the charging and discharging efficiency of the laminated battery can be further improved.

Similarly, the second folded-back portion 34 is located on the other side of the first direction d1 with respect to the other side end portion 10b of the positive electrode plate 10X adjacent to the negative electrode plate 20Y facing the second folded-back portion 34. That is, the extending portion 32 extends from the positive electrode plate 10X to the other side in the first direction d1. Since the extending portion 32 facing the vicinity of the other side end portion 10b of the positive electrode plate 10X holds the electrolytic solution, the electrolytic solution can be supplied to the vicinity of the other side end portion 10b of the positive electrode plate 10X. Therefore, the vicinity of the other side end portion 10b of the positive electrode plate 10X can be contributed to charging and discharging, and the charging and discharging efficiency of the laminated battery can be further improved.

Irregular irregularities are formed on both ends of the insulating sheet 30, that is, the extending portion 32, the first folded portion 33, and the second folded portion 34. In other words, the insulating sheet 30 is wrinkled at both ends in the first direction d1. Due to irregular irregularities (wrinkles), the surface area of the insulating sheet 30 in the extending portion 32, the first folded portion 33, and the second folded portion 34 is increased. The area where the extending portion 32, the first folded portion 33, and the second folded portion 34 of the insulating sheet 30 come into contact with the sealed electrolytic solution in the accommodation space formed by the exterior body 3 increases. The amount of the electrolytic solution supplied to the insulating sheet 30 increases as the area in contact with the electrolytic solution increases. Therefore, the electrolytic solution can be easily held in the extending portion 32, the first folded portion 33, and the second folded portion 34 of the insulating sheet 30. Since the electrolytic solution can be held in the vicinity of the one side end portion 10a of the positive electrode plate 10X and in the vicinity of the other side end portion 20b of the negative electrode plate 20Y, the electrolytic solution can be held in the vicinity of the one side end portion 10a of the positive electrode plate 10X and in the vicinity of the one side end portion 10a. The electrolytic solution can be supplied to the vicinity of the other side end portion 20b of the negative electrode plate 20Y. Therefore, the vicinity of the one side end portion 10a of the positive electrode plate 10X and the vicinity of the other side end portion 20b of the negative electrode plate 20Y can be contributed to charging and discharging, and the charging and discharging efficiency of the laminated battery can be improved. it can.

Irregular irregularities (wrinkles) in the extending portion 32, the first folded portion 33, and the second folded portion 34 of the insulating sheet 30 indicate that the base material layer 35 constituting the insulating sheet 30 is formed of a porous body. , Easy to form. In particular, when a resin porous film (a porous body of a polyolefin polymer such as polypropylene or polyethylene) is used as the insulating sheet 30, unevenness (wrinkles) that easily exerts the above-mentioned effect is likely to be formed.

Further, the insulating sheet 30 preferably has a functional layer 36 containing an inorganic material. Since the functional layer 36 containing the inorganic material has a high porosity, it can hold a larger amount of electrolytic solution. Therefore, the insulating sheet 30 can sufficiently hold the electrolytic solution, and the positive electrode plate 10X and the negative electrode plate 20Y can be efficiently contributed to charging and discharging. That is, the efficiency of charging and discharging the laminated battery can be improved.

Since the negative electrode plate 20Y is longer than the positive electrode plate 10X in the first direction d1, the negative electrode plate 20Y is difficult to face the portion where the electrolytic solution is held. In this respect, it is preferable that the insulating sheet 30 is arranged so that the side of the insulating sheet 30 provided with the functional layer 36 faces the negative electrode plate 20Y. By facing the side where the electrolytic solution is sufficiently held to the negative electrode plate 20Y, the electrolytic solution can be sufficiently supplied to the negative electrode plate 20Y. Therefore, the negative electrode plate 20Y can be efficiently contributed to charging and discharging, and the charging and discharging efficiency of the laminated battery can be improved.

Further, the temperature of the positive electrode plate 10X side tends to be higher than that of the negative electrode plate 20Y. If, for example, the base material layer 35 containing polyethylene faces the side of the positive electrode plate 10X, polyethylene may be exposed to a high temperature and become polyene. When polyethylene becomes polyene, the insulating property of the base material layer 35 is lost. In this respect, the layer of the insulating sheet 30 facing the positive electrode plate 10X side preferably has heat resistance. In this respect, the functional layer 36 containing the inorganic material has excellent heat resistance. That is, the functional layer 36 is unlikely to deteriorate even when exposed to a high temperature. Therefore, when the insulating sheet 30 is arranged so that the side of the insulating sheet 30 provided with the functional layer 36 faces the side of the positive electrode plate 10X which tends to become hot, even if the positive electrode plate 10X becomes hot, it is insulated. The insulating property of the sheet 30 can be maintained.

Further, the length S3 in the first direction d1 between the first folded portion 33, the positive electrode plate 10X facing the first folded portion 33, and the one side end portion 20a of the negative electrode plate 20Y adjacent to the stacking direction dL is The length S2 in the first direction d1 between the second folded-back portion 34 and the other side end portion 20b of the negative electrode plate 20Y facing the second folded-back portion 34 is shorter. On one side of the first direction d1, the extending portion 32 has a length necessary and sufficient to supply the electrolytic solution to the positive electrode plate 10X and efficiently contribute to charging and discharging the positive electrode plate 10X. Not as long as needed. That is, the overall size of the laminated battery 1 can be made compact. Since the volume of the laminated battery 1 can be reduced while the positive electrode plate 10X and the negative electrode plate 20Y efficiently contribute to charging and discharging, the battery capacity (energy density) per unit volume can be increased.

Further, the first folded portion 33 and the second folded portion 34 are in contact with the outer body 3 in a state where the membrane electrode assembly 5 is housed in the outer body 3. In other words, the dimensions of the exterior body 3 are designed so that the length of the housing portion defined by the exterior body 3 in the first direction d1 matches the length of the membrane electrode assembly 5. In this case, the dimensions of the exterior body 3 are not unnecessarily long. That is, the overall size of the laminated battery 1 can be made compact. Therefore, the battery capacity (energy density) per unit volume of the laminated battery 1 can be increased.

Next, a method for manufacturing the laminated battery 1 according to the present embodiment, which is configured as a lithium ion secondary battery, will be described. The method for manufacturing the laminated battery 1 described below includes a step of manufacturing the positive electrode plate 10X (first electrode plate 10), the negative electrode plate 20Y (second electrode plate 20), and the insulating sheet 30, and the insulating sheet 30 is folded in a row. It includes a step of alternately laminating the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20) while folding back into a shape.

First, the steps of manufacturing the positive electrode plate 10X (first electrode plate 10), the negative electrode plate 20Y (second electrode plate 20), and the insulating sheet 30 will be described. The positive electrode plate 10X, the negative electrode plate 20Y, and the insulating sheet 30 may be manufactured at different timings by different steps. Further, the positive electrode plate 10X, the negative electrode plate 20Y and the insulating sheet 30 are simultaneously manufactured in parallel, and the manufactured positive electrode plate 10X and the negative electrode plate 20Y are sequentially folded back in a zigzag manner while the positive electrode plate 10X (first). It may be supplied to the step of alternately laminating via the electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20).

The positive electrode plate 10X is formed by, for example, coating a composition (slurry) that constitutes the positive electrode active material layer 12X on a long aluminum foil that constitutes the positive electrode current collector 11X and solidifying the positive electrode plate 10X. Next, it can be produced by cutting it to a desired size. Similarly, in the negative electrode plate 20Y, for example, a composition (slurry) that constitutes the negative electrode active material layer 22Y is applied onto a long copper foil that constitutes the negative electrode current collector 21Y. It can be produced by solidifying and then cutting to a desired size. The insulating sheet 30 can be produced, for example, by forming a functional layer 36 containing an inorganic material on a base material layer 35 formed of a porous body by coating and cutting it into a desired size.

Next, a step of alternately laminating the insulating sheet 30 via the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20) while folding back the insulating sheet 30 in a zigzag manner will be described. This step can be performed using, for example, an apparatus as described in Patent Document 1 (Japanese Unexamined Patent Publication No. 2014-165055). That is, the insulating sheets 30 are alternately folded back, and each time the insulating sheet 30 is folded back, the positive electrode plate 10X and the negative electrode plate 20Y are alternately supplied onto the folded insulating sheet 30. However, unlike the process described in Patent Document 1, between the first folded portion 33 of the insulating sheet 30 and the one side end portion 10a of the positive electrode plate 10X facing the first folded portion 33 in the first direction d1. The insulating sheet 30 is folded back so that a gap 40 is provided between the second folded-back portion 34 and the other side end portion 20b of the negative electrode plate 20Y facing the second folded-back portion 34 in the first direction d1. .. In other words, the insulating sheet 30 is folded back so as to form the first folded-back portion 33 on one side of the one-side end portion 10a of the positive electrode plate 10X, and is folded back on the other side of the other-side end portion 20b of the negative electrode plate 20Y. It is folded back to form a portion 34. That is, the insulating sheet 30 is folded back so as to form the extending portion 32.

Further, in this step, the positive electrode plate 10X and the negative electrode plate 20Y are laminated so that the positive electrode active material layer 12X of the positive electrode plate 10X and the negative electrode active material layer 22Y of the negative electrode plate 20Y face each other. When the positive electrode active material layer 12X and the negative electrode active material layer 22Y do not face each other between the positive electrode plate 10X and the negative electrode plate 20Y, the effective areas of the positive electrode plate 10X and the negative electrode plate 20Y are reduced to obtain the planned capacity. However, there is a possibility that the positive electrode plate 10X and the negative electrode plate 20Y are short-circuited to cause sparks. Further, in the laminated battery 1 configured as a lithium ion secondary battery, the positive electrode plate 10X does not face the negative electrode plate 20Y, so that lithium precipitates are generated, which damages the membrane electrode assembly 5 and the exterior body 3. It can also cause.

As described above, after the insulating sheet 30 is folded back in a zigzag manner and alternately laminated via the positive electrode plate 10X (first electrode plate 10) and the negative electrode plate 20Y (second electrode plate 20), the plurality of positive electrode plates 10X are formed. , At one end of the second direction d2, they are joined to each other and become conductive. Then, the tab 4 is electrically connected to one end of the second direction d2. Similarly, the plurality of negative electrode plates 20Y are joined to each other and become conductive at the other end of the second direction d2. Then, the tab 4 is electrically connected to the other end of the second direction d2.

After that, the laminated battery 1 is obtained by sealing the membrane electrode assembly 5 together with the electrolytic solution in the exterior body 3 so that each tab 4 extends from the exterior body 3. The membrane electrode assembly 5 is housed in the exterior body 3 so that the first folded-back portion 33 and the second folded-back portion 34 of the insulating sheet 30 come into contact with the exterior body 3.

The material of the insulating sheet 30, the amount of the electrolytic solution sealed in the exterior body 3, the internal pressure of the exterior body 3, and the like are appropriately adjusted and combined within the range selected by the conventional laminated battery. The unevenness shown in 8 can be formed on the extending portion 32 and the folded portion 33, 34 of the insulating sheet 30. For the insulating sheet 30, it is possible to facilitate the formation of irregularities by selecting a flexible porous body, for example, a resin porous film using a polyolefin-based polymer such as polypropylene or polyethylene, as the base material layer 35. it can. Further, the amount of the electrolytic solution sealed affects the degree of the insulating sheet 30. By setting the internal pressure of the exterior body 3 to a negative pressure and compressing the insulating portion 31 of the insulating sheet 30 to some extent, the extending portion 32 and the folded portions 33 and 34 are more likely to absorb the electrolytic solution than the insulating portion 31. As a result, the extending portion 32 and the folded portion 33, 34 are more likely to swell than the insulating portion 31, and at this time, it is possible to promote the generation of local unevenness on the extending portion 32 and the folded portion 33, 34. it can.

As described above, in the laminated battery 1 of the present embodiment, the plurality of electrode plates 10 and 20 laminated in the stacking direction dL are alternately arranged in the width direction (first direction d1) non-parallel to the stacking direction dL. An insulating sheet 30 which is folded back and arranged between two electrode plates 10 and 20 adjacent to each other in the stacking direction dL is provided, and the folded-back portions 33 and 34 of the insulating sheet 30 and the folded-back portions 33 and 34 are formed in the width direction. A gap 40 is provided between the end portions 10a and 20b of the facing electrode plates 10 and 20. According to such a laminated battery 1, the electrolytic solution can be held in the portions facing the vicinity of the ends 10a and 20b of the electrode plates 10 and 20, so that the ends 10a and 20b of the electrode plates 10 and 20 can be held. An electrolytic solution can be supplied in the vicinity of the above to contribute to charging and discharging. Therefore, in the laminated battery 1 having the zigzag-shaped insulating sheet 30, the efficiency of charging and discharging can be improved.

In the laminated battery 1 of the present embodiment, the length S1 between the folded-back portions 33, 34 along the width direction and the end portions 10a, 20b of the electrode plates 10, 20 facing the folded-back portions 33, 34. S2 is 5 times or more, or 10 times or more, the thicknesses T1 and T2 of the electrode plates 10 and 20. According to such a laminated battery 1, the portions facing the vicinity of the end portion 10a of the positive electrode plate 10X and the vicinity of the end portion 20b of the negative electrode plate 20Y can sufficiently retain the electrolytic solution. Therefore, the electrolytic solution can be sufficiently supplied to the vicinity of the end portion 10a of the positive electrode plate 10X and the vicinity of the end portion 20b of the negative electrode plate 20Y to sufficiently contribute to charging and discharging. That is, the efficiency of charging and discharging the laminated battery can be further improved.

Further, in the laminated battery 1 of the present embodiment, irregularities are formed on the folded-back portions 33 and 34. According to such a laminated battery 1, in the folded portions 33 and 34, the insulating sheet 30 increases the surface area and the area in contact with the electrolytic solution. Therefore, the electrolytic solution can be easily held in the vicinity of the folded portions 33 and 34 of the insulating sheet 30. Therefore, since the electrolytic solution can be held in the vicinity of the end portion 10a of the positive electrode plate 10X and the vicinity of the end portion 20b of the negative electrode plate 20Y, the electrolytic solution can be held in the vicinity of the end portion 10a of the positive electrode plate 10X and the negative electrode plate 20Y. An electrolytic solution can be supplied in the vicinity of the end portion 20b to contribute to charging and discharging. That is, the efficiency of charging and discharging the laminated battery can be improved.

Further, in the laminated battery 1 of the present embodiment, the insulating sheet 30 has a base material layer 35 formed of a porous body. Since the porous body has flexibility, according to such a laminated battery 1, unevenness is likely to be formed in the folded portions 33 and 34 of the insulating sheet 30. Therefore, the effect of improving the charging and discharging efficiency of the above-mentioned laminated battery can be easily achieved.

Further, in the laminated battery 1 of the present embodiment, the insulating sheet 30 has a functional layer 36 containing an inorganic material. According to such a laminated battery 1, since the insulating sheet 30 easily holds the electrolytic solution, the positive electrode plate 10X and the negative electrode plate 20Y can be efficiently contributed to charging and discharging. Therefore, the efficiency of charging and discharging the laminated battery can be improved.

Further, in the laminated battery 1 of the present embodiment, the plurality of electrode plates 10 and 20 have the first electrode plates 10 alternately laminated in the stacking direction dL and the first electrode plates 10 having a length along the width direction. The folded-back portions 33 and 34 include a second electrode plate 20 longer than the second electrode plate 20, and the folded-back portions 33 and 34 have a first folded-back portion 33 that folds back the insulating sheet 30 on one side in the width direction and a second folded-back portion 33 that folds back the insulating sheet 30 on the other side in the width direction. The first folded-back portion 33, including the portion 34, is wider than the one-sided end portion 20a in the width direction of the second electrode plate 20 adjacent to the first electrode plate 10 facing the first folded-back portion 33. Located on one side in the direction. According to such a laminated battery 1, since the portion of the insulating sheet 30 facing the vicinity of the end portion 20a on one side of the negative electrode plate 20Y holds the electrolytic solution, the vicinity of the one side end portion 20a of the negative electrode plate 20Y. The electrolytic solution can be supplied to the battery to contribute to charging and discharging, and the efficiency of charging and discharging of the laminated battery can be further improved.

Further, in the laminated battery 1 of the present embodiment, the plurality of electrode plates 10 and 20 have the first electrode plates 10 alternately laminated in the stacking direction dL and the first electrode plates 10 having a length along the width direction. The folded-back portions 33 and 34 include a second electrode plate 20 longer than the second electrode plate 20, and the folded-back portions 33 and 34 have a first folded-back portion 33 that folds back the insulating sheet 30 on one side in the width direction and a second folded-back portion 33 that folds back the insulating sheet 30 on the other side in the width direction. The width between the first folded-back portion 33 and the one-sided end portion 20a in the width direction of the second electrode plate 20 adjacent to the first electrode plate 10 facing the first folded-back portion 33, including the portion 34. The length S3 in the direction is shorter than the length in the width direction between the second folded-back portion 34 and the other side end portion 20b in the width direction of the second electrode plate 20 facing the second folded-back portion 34. According to such a laminated battery 1, since the overall size of the laminated battery 1 can be made compact, the volume of the laminated battery 1 is increased while the positive electrode plate 10X and the negative electrode plate 20Y are efficiently contributed to charging and discharging. Can be reduced, so that the battery capacity (energy density) per unit volume can be increased.

Further, in the laminated battery 1 of the present embodiment, the plurality of electrode plates 10 and 20 are the first electrode plates 10 alternately laminated in the stacking direction dL and the first electrode plates 10 having a length along the width direction. The insulating sheet 30 includes a second electrode plate 20 longer than the second electrode plate 20, and has a base material layer 35 and a functional layer 36 laminated on the base material layer 35 and having a higher porosity than the base material layer 35, and is insulated. The side of the sheet 30 provided with the base material layer 35 faces the first electrode plate 10, and the side provided with the functional layer 36 faces the second electrode plate 20. According to such a laminated battery 1, the side of the insulating sheet 30 in which a larger amount of the electrolytic solution is held faces the wide negative electrode plate 20Y, so that the negative electrode plate 20Y is sufficiently supplied with the electrolytic solution. It can efficiently contribute to charging and discharging.

Further, in the laminated battery 1 of the present embodiment, the plurality of electrode plates 10 and 20 have the first electrode plates 10 alternately laminated in the stacking direction dL and the first electrode plates 10 having a length along the width direction. The insulating sheet 30 includes a second electrode plate 20 longer than the second electrode plate 20, and has a base material layer 35 and a functional layer 36 laminated on the base material layer 35 and having heat resistance higher than that of the base material layer 35, and is insulated. The side of the sheet 30 where the base material layer 35 is provided faces the second electrode plate 20, and the side where the functional layer 36 is provided faces the first electrode plate 10. According to such a laminated battery 1, the insulating sheet 30 is arranged so that the side provided with the functional layer 36 of the insulating sheet 30 faces the side of the positive electrode plate 10X where the temperature tends to be high. Even if the plate 10X becomes hot, the functional layer 36 does not deteriorate, and the insulating property of the insulating sheet 30 can be maintained.

Further, the laminated battery 1 of the present embodiment further includes an exterior body 3 accommodating the electrode plates 10 and 20 and the insulating sheet 30, and the folded-back portions 33 and 34 are in contact with the exterior body 3. According to such a laminated battery 1, the overall size of the laminated battery 1 can be made compact, and the battery capacity (energy density) per unit volume of the laminated battery 1 can be increased.

Further, the laminated battery 1 of the present embodiment includes 20 or more electrode plates 10 and 20 in total. According to such a laminated battery 1, the effect of improving the charging and discharging efficiency due to the provision of the gap 40 can be remarkably exhibited.

In the above, one embodiment has been described with reference to specific examples, but the above-mentioned specific examples are not intended to limit one embodiment. The above-described embodiment can be implemented in various other specific examples, and various omissions, replacements, and changes can be made without departing from the gist thereof.

For example, in the above-described embodiment, the insulating sheet 30 has a base material layer 35 and a functional layer 36. However, the insulating sheet 30 may not have the functional layer 36. Since such an insulating sheet 30 is more flexible than the insulating sheet having the functional layer 36, it is easily deformed. Therefore, irregular irregularities (wrinkles) are likely to be formed on both ends of the insulating sheet 30, that is, the extending portion 32, the first folded portion 33, and the second folded portion 34. As described above, the surface area of the insulating sheet 30 in the extending portion 32, the first folded portion 33, and the second folded portion 34 is increased due to the irregular unevenness (wrinkles). The area where the extending portion 32, the first folded portion 33, and the second folded portion 34 of the insulating sheet 30 come into contact with the sealed electrolytic solution in the accommodation space formed by the exterior body 3 increases. The amount of the electrolytic solution supplied to the insulating sheet 30 increases as the area in contact with the electrolytic solution increases. Therefore, it becomes easy to hold the electrolytic solution in the portion facing the vicinity of the end portion 10a of the positive electrode plate 10X and the vicinity of the end portion 20b of the negative electrode plate 20Y. Therefore, the electrolytic solution can be supplied to the vicinity of the one side end portion 10a of the positive electrode plate 10X and the vicinity of the other side end portion 20b of the negative electrode plate 20Y. The vicinity of the end portion 10a of the positive electrode plate 10X and the vicinity of the end portion 20b of the negative electrode plate 20Y can be contributed by charging and discharging, and the charging and discharging efficiency of the laminated battery can be further improved.

1 Laminated battery 3 Exterior 4 Tab 5 Film electrode joint 10 First electrode plate 10X Positive electrode plate 10a One side end 10b Other side end 11 First electrode current collector 11X Positive electrode current collector 11a First surface 11b First 2 sides 12 1st electrode active material layer 12X Positive electrode active material layer 20 2nd electrode plate 20Y Negative electrode plate 20a One side end 20b Other side end 21 2nd electrode current collector 21Y Negative electrode current collector 22 2nd electrode active material Layer 22Y Negative electrode active material layer 30 Insulation sheet 31 Insulation part 32 Extension part 33 First folded part 34 Second folded part 35 Base material layer 36 Functional layer 40 Gap

Claims (11)

Multiple electrode plates stacked in the stacking direction and
An insulating sheet that is alternately folded back in a width direction non-parallel to the stacking direction and arranged between two electrode plates adjacent to each other in the stacking direction is provided.
A gap is provided between the folded-back portion of the insulating sheet and the end portion of the electrode plate facing the folded-back portion in the width direction.
The length between the end portion of the electrode plate facing said folded portion and the folded portion along the width direction state, and are five times more than the thickness of the electrode plate,
The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The folded portion includes a first folded portion that folds the insulating sheet on one side in the width direction, and a second folded portion that folds the insulating sheet on the other side in the width direction.
The first folded portion is laminated so as to be located on one side in the width direction of the second electrode plate adjacent to the first electrode plate facing the first folded portion with respect to one end in the width direction. Molded battery. The laminated battery according to claim 1, wherein the folded portion has irregularities. The first or second claim, wherein the length between the folded portion along the width direction and the end portion of the electrode plate facing the folded portion is 10 times or more the thickness of the electrode plate. Stacked battery. The laminated battery according to any one of claims 1 to 3, wherein the insulating sheet has a base material layer formed of a porous body. The laminated battery according to any one of claims 1 to 4, wherein the insulating sheet has a functional layer containing an inorganic material. The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The folded portion includes a first folded portion that folds the insulating sheet on one side in the width direction, and a second folded portion that folds the insulating sheet on the other side in the width direction.
The length in the width direction between the first folded portion and the end on one side in the width direction of the second electrode plate adjacent to the first electrode plate facing the first folded portion is the second. The invention according to any one of claims 1 to 5 , which is shorter than the length in the width direction between the folded portion and the end portion of the second electrode plate facing the second folded portion on the other side in the width direction. Stacked battery. The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The insulating sheet has a base material layer and a functional layer laminated on the base material layer and having a higher porosity than the base material layer.
Any of claims 1 to 6 , wherein the side of the insulating sheet provided with the base material layer faces the first electrode plate, and the side provided with the functional layer faces the second electrode plate. The laminated battery according to the first item. The plurality of electrode plates include a first electrode plate that is alternately laminated in the stacking direction and a second electrode plate whose length along the width direction is longer than that of the first electrode plate.
The insulating sheet has a base material layer and a functional layer laminated on the base material layer and having heat resistance higher than that of the base material layer.
Any of claims 1 to 6 , wherein the side of the insulating sheet provided with the base material layer faces the second electrode plate, and the side provided with the functional layer faces the first electrode plate. The laminated battery according to the first item. The laminated battery according to any one of claims 1 to 8 , wherein the first electrode plate is a positive electrode plate and the second electrode plate is a negative electrode plate. Further provided with an exterior body for accommodating the electrode plate and the insulating sheet,
The laminated battery according to any one of claims 1 to 9 , wherein the folded portion is in contact with the exterior body. The laminated battery according to any one of claims 1 to 10 , further comprising 20 or more electrode plates in total.