JP2019057444A - Power storage element - Google Patents

Abstract

To provide a power storage element including a container and an electrode body housed in the container, in which safety is improved.SOLUTION: A power storage element includes a container 101, an electrode body 400 housed in the container 101, a sidewall 620 placed on the side of the electrode body 400 in the container 101, and a negative electrode collector 800 bonded to the end of a negative electrode plate 420, i.e., a composite layer non-formation part 421a. The sidewall 620 has a long convex part 650 pressing a position of a separator 450, farther inside than the edge of the separator 450 on the composite layer non-formation part 421a side, when viewing from the side of the electrode body 400, and elongating along the edge of the separator 450.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a storage element including a container and an electrode body accommodated in the container.

  In Patent Document 1, for example, any position between the edge of the separator and the negative electrode plate is pressed from the side of the electrode body by a pressing member disposed at the end on the positive electrode side of the wound electrode body. A structure is disclosed. Patent Document 1 describes that the above structure suppresses the occurrence of defects due to foreign matters such as metal powder.

Japanese Patent Laid-Open No. 2006-178025

  In an electrode body in which a positive electrode plate and a negative electrode plate are laminated via a separator, such as a wound electrode body, as described above, it is caused by conductive foreign matter (contamination) such as a metal piece or metal powder. In addition to the problem of failure, there is also a problem of heat shrinkage of the separator. In other words, when the electrode body becomes hot due to some abnormality, the separator that insulates the positive electrode plate from the negative electrode plate shrinks due to heat, and as a result, due to contact between the positive electrode plate and the negative electrode plate, etc. The element may become more unstable. Further, the thermal contraction of the separator and the penetration of contamination into the electrode body can occur on the positive electrode side and the negative electrode side of the electrode body, respectively.

  As a result of intensive studies by the inventors of this application, the positive electrode side and the negative electrode side of the electrode body are not the same in the positional relationship between the edges of the positive electrode plate and the negative electrode plate. It has been found that measures suitable for each of the positive electrode side and the negative electrode side are necessary.

  In view of the above-described conventional problems, an object of the present invention is to provide a power storage element including a container and an electrode body accommodated in the container, and having improved safety.

  In order to achieve the above object, a power storage element according to one embodiment of the present invention is a container and an electrode body accommodated in the container, and is disposed between the negative electrode plate and the positive electrode plate, and the negative electrode plate and the positive electrode plate. An electrode body formed by laminating the separators formed, a side member disposed on the side of the electrode body inside the container, and a negative electrode end that is an end of the negative electrode plate, A convex portion that presses a position inside the negative electrode end side edge of the separator when viewed from the side of the electrode body. And it has an elongate convex part in the direction along the said edge of the said separator.

  According to this configuration, the side member has a long convex portion along the edge of the separator, and the convex portion can press the end portion of the separator on the negative electrode side of the electrode body. Thereby, for example, the pressing force by the side member is efficiently applied to the edge of the separator, and as a result, the thermal contraction of the separator on the negative electrode side of the electrode body is suppressed. In addition, on the negative electrode side of the electrode body, the possibility of closing the gap between separator edges adjacent in the stacking direction or between the separator edge and the electrode plate (positive electrode plate or negative electrode plate) is improved. Intrusion into the electrode body is suppressed, and as a result, the possibility of occurrence of defects due to contamination is reduced. Thus, the power storage device according to this aspect is a power storage device with improved safety.

  In the energy storage device according to one embodiment of the present invention, the convex portion may press a position outside the positive electrode plate when viewed from the side of the electrode body.

  According to this configuration, for example, the edges of the separator are closed at a position before the positive electrode plate when viewed from the negative electrode end. Thereby, for example, copper contamination generated in the joining process of the negative electrode end portion and the conductive member does not easily reach a portion of the positive electrode plate close to the negative electrode end portion. Therefore, generation | occurrence | production of the fine short circuit resulting from a copper contamination contacting a positive electrode plate is suppressed.

  In the energy storage device according to one embodiment of the present invention, the negative electrode plate includes a negative electrode mixture layer forming portion, and the convex portion is the negative electrode composite when viewed from the side of the electrode body. It is good also as pressing the position where a material layer formation part exists.

  Here, the negative electrode end portion joined to the conductive member is a non-mixed material layer forming portion in the negative electrode plate, and is a thin and soft portion. The convex part of the side member according to this aspect presses the separator from the side in order to press the existence range of the part where the composite material layer forming part is laminated inside the negative electrode end part which is the thin and soft part. You can hold down more firmly.

  Further, a power storage element according to one embodiment of the present invention is a stack of a container, an electrode body housed in the container, and a negative electrode plate and a positive electrode plate, and a separator disposed between the negative electrode plate and the positive electrode plate. An electrode body formed in the container, a side member disposed on the side of the electrode body inside the container, and a conductive member joined to a positive electrode end that is an end of the positive electrode plate, The negative electrode plate has a negative electrode mixture layer forming portion, the positive electrode plate has a positive electrode mixture layer forming portion, and the side member is an edge of the separator on the positive electrode end portion side. And the convex portion includes the negative electrode mixture layer forming portion when viewed from the side of the electrode body, and the positive electrode mixture. The position where the layer forming part does not exist is pressed.

  According to this configuration, the side member has a long convex portion along the edge of the separator, and the convex portion can press the end portion of the separator on the positive electrode side of the electrode body. Thereby, for example, the pressing force applied to the storage element by the side member is efficiently applied to the edge of the separator, and as a result, the thermal contraction of the separator on the positive electrode side of the electrode body is suppressed. Moreover, since the convex part of a side member presses the outer side (range in which a positive electrode end part exists) from a positive electrode composite material layer formation part, when the electrode body is seen from the positive electrode end part side, the positive electrode mixture layer The separator is pressed at a position in front of the forming portion. Thereby, for example, it becomes difficult for copper contamination moving in the electrolytic solution to reach the positive electrode mixture layer forming portion. As a result, the possibility of occurrence of defects due to copper contamination is reduced.

  Here, the positive electrode end portion joined to the conductive member is a non-mixed material layer forming portion in the positive electrode plate, and is a thin and soft portion. The convex part of the side member according to the present aspect is present inside the part where the negative electrode mixture layer forming part is laminated, which is inside the part where only the positive electrode end and the separator, which are thin and soft, are laminated. Press from the side. Therefore, on the positive electrode side of the electrode body where copper contamination is likely to be ionized, the separator is firmly held outside the positive electrode mixture layer forming portion, and as a result, there are problems such as a micro short circuit due to copper contamination. , More reliably suppressed.

  Further, in the energy storage device according to one aspect of the present invention, the side member has a range in which the positive electrode mixture layer forming portion is present when the electrode body is viewed from the side. It is good also as having the said convex part in the position which does not press.

  According to this configuration, for example, when the electrode body is viewed from the side, the side member presses the separator at a position outside the positive electrode mixture layer forming portion, and the positive electrode mixture layer forming portion exists. Does not hold down the range. Therefore, the pressing force applied to the power storage element by the side member can be efficiently used as a force for pressing the edge of the separator, and the positive electrode by, for example, excessively pressing the electrode body by the side member. Problems such as damage to the plate or the negative electrode plate can be prevented.

  In the energy storage device according to one aspect of the present invention, the electrode body is formed by winding the negative electrode plate, the positive electrode plate, and the separator around a winding axis, The protruding amount of the central portion in the direction may be larger than the other portions.

  According to this configuration, the shape of the convex portion of the side member is a shape in which the central portion protrudes from the others, so that it is possible to more reliably hold the central portion, which is a dent-prone portion in the wound electrode body. it can. That is, the effectiveness of the effect of pressing the separator by the convex portion of the side member is improved.

  ADVANTAGE OF THE INVENTION According to this invention, it is an electrical storage element provided with the electrode body accommodated in the container and the container, Comprising: The electrical storage element with improved safety | security can be provided.

It is a perspective view which isolate | separates the container main body and shows the structure of the electrical storage element which concerns on embodiment. It is a perspective view which isolate | separates the spacer which shows the structure arrange | positioned inside the container main body of the electrical storage element which concerns on embodiment. It is a perspective view which shows the external appearance of the positive electrode collector which concerns on embodiment, and a negative electrode collector. It is a perspective view which shows the structure outline | summary of the electrode body which concerns on embodiment. It is a top view of the spacer which concerns on embodiment. It is a fragmentary sectional view of the electrical storage element which shows the arrangement position of the spacer in the electrical storage element which concerns on embodiment. It is a figure which shows an example of the position of the convex part of the spacer in the negative electrode side of the electrode body which concerns on embodiment. It is a figure which shows an example of the position of the convex part of the spacer in the positive electrode side of the electrode body which concerns on embodiment. It is a front view which shows the structure of the spacer which concerns on the modification 1 of embodiment. It is a figure which shows the structure of the convex part which the spacer which concerns on the modification 2 of embodiment has.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each figure is a schematic diagram and is not necessarily illustrated exactly.

  In addition, the embodiment described below and its modification examples show specific examples of the present invention. The shapes, materials, constituent elements, arrangement positions and connecting forms of constituent elements, order of manufacturing steps, and the like shown in the following embodiments and modifications thereof are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements.

  In the following description and drawings in the embodiments, the direction in which the pair of electrode terminals included in the power storage element is aligned, the direction in which the pair of current collectors are aligned, and both ends of the electrode body (the pair of material layer non-forming portions) Are defined as the X-axis direction. Moreover, the opposing direction of the long side surface of the container, the short side direction of the short side surface of the container, or the thickness direction of the container is defined as the Y-axis direction. In addition, the direction in which the container body and the cover plate of the electricity storage element are arranged, the longitudinal direction of the short side surface of the container, the extending direction of the legs of the current collector, or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect (orthogonal in this embodiment). Although the case where the Z-axis direction does not become the vertical direction may be considered depending on the usage mode, the Z-axis direction will be described below as the vertical direction for convenience of explanation. In the following description, for example, the X axis direction plus side indicates the arrow direction side of the X axis, and the X axis direction minus side indicates the opposite side to the X axis direction plus side. The same applies to the Y-axis direction and the Z-axis direction.

(Embodiment)
[1. General description of storage element]
First, a general description of the energy storage device 100 according to the embodiment will be described with reference to FIGS. 1, 2A, and 2B. FIG. 1 is a perspective view showing a configuration of a power storage device 100 according to an embodiment with a container body 110 separated. FIG. 2A is a perspective view showing a configuration of the electricity storage device 100 according to the embodiment arranged inside the container body 110, with the spacers 500 and 600 separated. FIG. 2B is a perspective view illustrating an appearance of the positive electrode current collector 700 and the negative electrode current collector 800 according to the embodiment.

  The power storage element 100 is a secondary battery that can charge electricity and discharge electricity, and specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage element 100 is used, for example, for an automobile power source such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), an electronic device power source, and a power storage power source. In addition, the electrical storage element 100 is not limited to a nonaqueous electrolyte secondary battery, A secondary battery other than a nonaqueous electrolyte secondary battery may be sufficient, and a capacitor may be sufficient as it. In addition, the storage element 100 may be a primary battery that can use stored electricity without being charged by a user, instead of a secondary battery. Further, in this embodiment, the rectangular parallelepiped (rectangular) power storage element 100 is illustrated, but the shape of the power storage element 100 is not particularly limited, and may be a cylindrical shape, a long cylindrical shape, or the like. Also, a laminate type power storage element can be provided.

  As shown in FIG. 1, the electricity storage device 100 includes a container 101 having a container body 110 and a cover plate 120, a positive electrode terminal 200, a positive electrode gasket 210, a negative electrode terminal 300, a negative electrode gasket 310, an electrode body 400, Spacers 500 and 600 are provided. In addition, as illustrated in FIG. 2A, the power storage device 100 further includes a positive electrode current collector 700 and a negative electrode current collector 800.

  In addition, although the electrolyte solution (nonaqueous electrolyte) is enclosed in the inside of the container 101, illustration is abbreviate | omitted. Note that there is no particular limitation on the type of the electrolytic solution as long as it does not impair the performance of the power storage element 100, and various types can be selected. In addition to the above-described components, a liquid injection part for injecting an electrolytic solution into the container 101 or an insulating film that wraps the electrode body 400 and the like may be disposed.

  The container 101 is a rectangular parallelepiped (box-shaped) case formed of a rectangular tube-shaped container body 110 having a bottom and a cover plate 120 that is a plate-like member that closes the opening of the container body 110. Specifically, the cover plate 120 is a flat and rectangular wall portion extending in the X-axis direction, and is disposed on the plus side of the container body 110 in the Z-axis direction. Further, the cover plate 120 is provided with a gas discharge valve 190 for releasing the pressure inside the container 101. The container body 110 has a flat and rectangular bottom wall on the negative side in the Z-axis direction, a flat and rectangular long side wall on both sides in the Y-axis direction, and a flat and flat on both sides in the X-axis direction. It has five wall parts of a rectangular short side wall part.

  Further, in the container 101, after the electrode body 400, the spacers 500 and 600, the positive electrode current collector 700, the negative electrode current collector 800, and the like are accommodated inside the container main body 110, the container main body 110 and the lid plate 120 are welded. Thus, the inside can be sealed. In addition, the material of the container main body 110 and the cover plate 120 is not specifically limited, For example, weldable metals, such as stainless steel, aluminum, an aluminum alloy, iron, a plated steel plate, are employ | adopted. In addition, a resin may be used as the material of the container body 110 and the lid plate 120.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 400. The positive electrode terminal 200 and the negative electrode terminal 300 are attached to the cover plate 120 disposed above the electrode body 400.

  Specifically, the positive electrode terminal 200 is fixed to the lid plate 120 via the positive electrode gasket 210, and is connected to the positive electrode current collector 700 through a shaft portion that penetrates the lid plate 120. The negative electrode terminal 300 is fixed to the cover plate 120 via a negative electrode gasket 310 and is connected to the negative electrode current collector 800 by a shaft portion that penetrates the cover plate 120.

  The positive electrode gasket 210 is an insulating sealing member disposed between the cover plate 120, the positive electrode terminal 200, and the positive electrode current collector 700. The positive electrode gasket 210 is made of, for example, a resin such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), or polyphenylene sulfide resin (PPS). Since the negative electrode gasket 310 has the same configuration as the positive electrode gasket 210, detailed description thereof is omitted.

  The positive electrode current collector 700 is an example of a conductive member joined to the end portion of the positive electrode plate of the electrode body 400, and the negative electrode current collector 800 is a conductive member joined to the end portion of the negative electrode plate of the electrode body 400. It is an example. As shown in FIG. 2B, the negative electrode current collector 800 has a leg portion 820 that is a part to be joined to the electrode body 400, and the positive electrode current collector 700 is joined to the electrode body 400 as shown in FIG. 2B. It has a leg 720 which is a portion to be processed.

  For example, ultrasonic bonding is used as a method for bonding the electrode body 400 to each of the positive electrode current collector 700 and the negative electrode current collector 800. The joining method is not limited to ultrasonic joining, and various methods such as resistance welding or clinch joining may be employed. The configuration of the electrode body 400 will be described later with reference to FIG.

  The spacers 500 and 600 are members disposed between both end portions of the electrode body 400 and both side walls of the container 101 so as to sandwich the electrode body 400 from both ends in the X-axis direction.

  The spacers 500 and 600 are made of an insulating material such as PP, PPS, PET, ceramic, and a composite material thereof. That is, the spacers 500 and 600 insulate the container 101 from the electrode body 400, the positive electrode current collector 700, and the negative electrode current collector 800. In addition, the spacers 500 and 600 fill the space between the electrode body 400, the positive electrode current collector 700, the negative electrode current collector 800, and the container 101, so that the electrode body 400, the positive electrode current collector 700, and the negative electrode current collector are filled. 800 supports the container 101 so as not to vibrate.

  Each of the spacers 500 and 600 has a side wall portion located on the side of the electrode body 400. Specifically, as shown in FIG. 2A, the spacer 500 includes a spacer main body 510 that faces the electrode body 400 in the X-axis direction, and a pair of side wall portions 520 that sandwich the electrode body 400 in the Y-axis direction. Similarly, the spacer 600 includes a spacer main body 610 that faces the electrode body 400 in the X-axis direction, and a pair of side wall portions 620 that sandwich the electrode body 400 in the Y-axis direction.

  A convex portion 550 is disposed on each of the pair of side wall portions 520, and a convex portion 650 is disposed on each of the pair of side wall portions 620. These convex portions 550 and 650 have a role of pressing the end portion of the separator of the electrode body 400. Each of the pair of side wall portions 520 and each of the pair of side wall portions 620 is an example of a side member. The structural relationship between the spacers 500 and 600 and the electrode body 400 will be described later with reference to FIGS.

[2. Configuration of electrode body]
Next, the structure of the electrode body 400 which concerns on embodiment is demonstrated using FIG. FIG. 3 is a perspective view illustrating a schematic configuration of the electrode body 400 according to the embodiment. In FIG. 3, elements such as electrode plates stacked and wound are partially developed and illustrated. 3 represents the winding axis of the electrode body 400. The alternate long and short dash line with the symbol W in FIG. The winding axis W is a virtual axis serving as a central axis when winding the electrode plate or the like, and is a straight line parallel to the X axis passing through the center of the electrode body 400 in the present embodiment. That is, in the present embodiment, the “direction of the winding axis W” is synonymous with the “X-axis direction”.

  The electrode body 400 is formed by being wound with a separator 450 interposed between a positive electrode plate 410 and a negative electrode plate 420. More specifically, in the present embodiment, as shown in FIG. 3, the electrode body 400 includes a separator 450a, a negative electrode plate 420, a separator 450b, and a positive electrode plate 410 that are stacked in this order, It is formed by turning. In other words, in the present embodiment, two long strip separators are used as the separator 450, and in FIG. 3, the two separators are indicated as a separator 450a and a separator 450b, respectively. Therefore, hereinafter, the “separator 450” means at least one of the separator 450a and the separator 450b. The outermost periphery of the electrode body 400 is formed by a separator 450 wound one or more times.

  As shown in FIG. 3, the electrode body 400 has a flat shape in a direction orthogonal to the winding axis W. That is, when viewed from the direction of the winding axis W, the electrode body 400 has an oval shape as a whole, the oval straight portion is flat, and the oval curved portion is curved. Become. For this reason, the electrode body 400 has a pair of opposed curved portions (a portion opposed in the Z-axis direction across the winding axis W) and an intermediate portion that is a portion between the pair of curved portions. .

  In the present embodiment, positive electrode plate 410 is a composite material layer forming portion 414 in which a positive electrode composite material layer containing a positive electrode active material is formed on the surface of a long metal foil (positive electrode base material layer 411) made of aluminum. including. The composite material layer forming part 414 is an example of a positive electrode composite material layer forming part. The negative electrode plate 420 includes a composite material layer forming portion 424 in which a negative electrode composite material layer containing a negative electrode active material is formed on the surface of a long strip-shaped metal foil (negative electrode base material layer 421) made of copper. The composite material layer forming part 424 is an example of a negative electrode composite material layer forming part. As the positive electrode active material and the negative electrode active material used for the electrode body 400, known materials can be appropriately used as long as the performance of the power storage device 100 is not impaired.

  In this embodiment, separators 450a and 450b have a microporous sheet made of resin as a base material.

  In the electrode body 400 configured as described above, more specifically, the positive electrode plate 410 and the negative electrode plate 420 are wound with a shift in the direction of the winding axis W via the separator 450a or 450b. And the positive electrode plate 410 and the negative electrode plate 420 have the mixed material layer non-formation part which is a part in which the mixed material layer is not formed of the base material layer in the edge part of each shifted direction.

  Specifically, the positive electrode plate 410 has, at one end in the direction of the winding axis W (end on the negative side in the X-axis direction), a mixture layer non-forming portion 411a in which no positive electrode mixture layer is formed. Yes. In addition, the negative electrode plate 420 has a mixture layer non-forming portion 421a on which the negative electrode mixture layer is not formed at the other end in the direction of the winding axis W (end on the plus side in the X-axis direction).

  In other words, the positive electrode converging portion is formed by the exposed metal foil (mixed material layer non-formed portion 411a) layer of the positive electrode plate 410, and the negative electrode plate 420 is exposed by the exposed metal foil (mixed material layer non-formed portion 421a) layer. A converging part is formed. The mixed material layer non-forming portion 411a constituting the positive electrode converging portion is an example of a positive electrode end portion, and is joined to the positive electrode current collector 700. The mixed material layer non-forming portion 421a constituting the negative electrode converging portion is an example of a negative electrode end portion, and is joined to the negative electrode current collector 800.

  In the present embodiment, an elliptical shape is illustrated as a cross-sectional shape of the electrode body 400, but an elliptical shape, a circular shape, a polygonal shape, or the like may be used. The shape of the electrode body 400 is not limited to the winding type, but may be a stacked type (stacked type) in which flat plate plates are stacked, or a shape in which the electrode plate is folded in a bellows shape (a zigzag folded shape). May be.

[3. Structural relationship between spacer and electrode body]
Next, the structural relationship between the spacers 500 and 600 and the electrode body 400 according to the present embodiment will be described with reference to FIGS.

  FIG. 4 is a plan view of spacer 600 according to the embodiment, and FIG. 5 is a partial cross-sectional view of power storage element 100 showing the arrangement position of spacer 600 in power storage element 100 according to the embodiment. Note that FIG. 5 illustrates a partial cross section of the energy storage device 100 in the XY plane passing through the line VV illustrated in FIG. 1. In the present embodiment, the overall configuration and arrangement of the spacer 500 and the spacer 600 are common. Therefore, in FIGS. 5 and 6, only the negative electrode side spacer 600 of the spacers 500 and 600 is illustrated, and illustration and description of the positive electrode side spacer 500 are omitted. Further, in FIG. 5, the approximate shape of the electrode body 400 is represented by a region with dots.

  As shown in FIGS. 4 and 5, the spacer 600 has a pair of side wall portions 620 that are located on the sides of the electrode body 400, and each of the pair of side wall portions 620 protrudes toward the electrode body 400. A convex portion 650 is disposed. The convex portion 650 is formed in a long shape in the direction (Z-axis direction) along the edge of the separator 450 on the side of the non-mixing material layer 421a (see FIG. 2A and FIG. 3). It arrange | positions at the spacer 600 so that it may press from the direction. That is, it can be said that the convex portion 650 is a rib extending in a direction orthogonal to the winding axis W in the side wall portion 620.

  Further, as shown in FIGS. 4 and 5, the pair of convex portions 650 included in the spacer 600 are provided at the same position in the X-axis direction (that is, at positions facing each other in the Y-axis direction) in the pair of side wall portions 620. ing. Similarly for the spacer 500, the pair of convex portions 550 are provided at the same position in the X-axis direction (that is, at positions facing each other in the Y-axis direction) on the pair of side wall portions 520.

  Specifically, the portion of the side wall portion 620 of the spacer 600 where the convex portion 650 is disposed is sandwiched between the inner surface of the container body 110 and the electrode body 400, and as a result, the convex portion 650 is the electrode body. A predetermined position 400 is pressed. More specifically, the position where the pair of convex portions 650 are pressed (the position indicated by the alternate long and short dash line in FIG. 5) is on the inner side (X-axis direction minus side) than the inclined portions on both sides in the Y-axis direction on the negative electrode side. is there. Moreover, as shown in FIG. 5, the position which a pair of convex part 650 presses is an inner side rather than the two inclination parts between the composite material layer non-formation parts 421a divided into two bundles. In other words, the pair of convex portions 650 press the high density portion of the elements (the positive electrode plate 410, the negative electrode plate 420, and the separator 450) that form the electrode body 400, in other words, the relatively hard portion, whereby the separator 450 is pressed. Can be pressed more firmly. Thereby, the suppression effect of the thermal contraction of the separator 450 by a pair of convex part 650 is improved. In the present embodiment, the spacer 500 arranged on the positive electrode side of the electrode body 400 is arranged in the same manner as the spacer 600. That is, each of the pair of convex portions 550 includes two inclined portions between the inclined portions on both sides in the Y-axis direction on the positive electrode side of the electrode body 400 and the mixture layer non-forming portion 411a divided into two bundles. It is in the state which presses the inner side (X-axis direction plus side) from the part. Thereby, the suppression effect of the thermal contraction of the separator 450 by a pair of convex part 550 is improved.

  Next, each example of the pressing position of the convex portion 650 and the convex portion 550 with respect to the electrode body 400 is related to the edge of the separator 450 and the edge of the composite material layer forming portion (414, 424) of the electrode plate. This will be described with reference to FIGS.

  FIG. 6 is a diagram illustrating an example of the position of the convex portion 650 of the spacer 600 on the negative electrode side of the electrode body 400 according to the embodiment. FIG. 7 is a diagram illustrating an example of the position of the convex portion 550 of the spacer 500 on the positive electrode side of the electrode body 400 according to the embodiment. 6 and 7, the positive electrode current collector 700 and the negative electrode current collector 800 are not shown, and the constituent elements of the electrode body 400 such as the positive electrode plate 410 and the negative electrode plate 420 are convex portions 650 or 550. It is illustrated in a simplified manner so that the positional relationship and the like are clear. Supplementary matters regarding FIGS. 6 and 7 also apply to FIG. 9 described later.

  As shown in FIG. 6, the convex portion 650 disposed on the side wall portion 620 of the spacer 600 is disposed so as to hold the end portion of the separator 450, and thereby the thermal contraction of the separator 450 on the negative electrode side of the electrode body 400. Etc. are suppressed.

  Specifically, the convex portion 650 included in the spacer 600 presses a position on the inner side of the electrode body 400 from the edge of the separator 450 on the side of the non-formed material layer forming portion 421a (the X axis direction plus side). That is, as shown in FIG. 6, the convex portion 650 is disposed on the inner side (position closer to the center of the electrode body 400 than the position Pa in the X-axis direction) from the position Pa of the edge of the separator 450.

  As described above, the power storage device 100 according to the present embodiment is the container 101 and the electrode body 400 accommodated in the container 101, and includes the negative electrode plate 420 and the positive electrode plate 410, and the negative electrode plate 420 and the positive electrode plate 410. The electrode body 400 formed by laminating the separator 450 disposed on the side of the electrode body 400, the side member (side wall portion 620) disposed on the side of the electrode body 400 inside the container 101, and the negative electrode plate 420 And a negative electrode current collector 800 bonded to the end portion of the composite material layer non-forming portion 421a. The side wall portion 620 is a convex portion 650 that presses a position on the inner side of the edge of the separator 450 on the side of the non-formed material layer portion 421a when viewed from the side of the electrode body 400. A long convex portion 650 is provided in a direction along the edge. Note that the side wall portion 620 that is an example of a side member in this embodiment is provided in the power storage element 100 as part of the spacer 600.

  As described above, in the present embodiment, the side wall portion 620 included in the spacer 600 has the long convex portion 650 along the edge of the separator 450, and the convex portion 650 is the negative electrode side of the electrode body 400. The end of the separator 450 can be pressed. Thereby, for example, the pressing force by the side wall portion 620 is efficiently applied to the end portion of the separator 450, and as a result, thermal contraction of the separator 450 on the negative electrode side of the electrode body 400 is suppressed. Further, on the negative electrode side of the electrode body 400, the possibility of closing the gap between the edges of the separators 450 adjacent in the stacking direction or the edge of the separator 450 and the electrode plate (the positive electrode plate 410 or the negative electrode plate 420) is improved. . Thereby, the penetration | invasion of the contamination to the inside of the electrode body 400 is suppressed, As a result, generation | occurrence | production possibility of the malfunction resulting from a contamination falls. Specifically, for example, when contamination, which is a minute metal piece, comes into contact with the composite material layer forming portion 414 of the positive electrode plate 410, the metal may be ionized at the positive electrode potential. In this case, when the ionized metal reaches the nearby negative electrode plate 420, the metal precipitates to form dendrites, and the dendrites penetrate the separator 450 and the fine particles between the positive electrode plate 410 and the negative electrode plate 420. May cause a short circuit. However, in the present embodiment, as described above, since the end of the separator 450 is pressed, the movement of the contamination is suppressed, and as a result, the possibility of occurrence of a problem due to the contamination is reduced.

  Here, for example, when the electrode body 400 is pressed on a relatively wide surface, the pressing force is dispersed on the surface (the pressing force per unit area becomes small). On the other hand, in the energy storage device 100 according to the present embodiment, since the electrode body 400 is pressed by the elongated convex portion 650 along the edge of the separator 450, the pressing force on the electrode body 400 is the end of the separator 450. Given to concentrate on. In other words, the side wall part 620 (spacer 600) has the convex part 650 which presses linearly along the direction of the edge of the separator 450. FIG. Therefore, it can be said that the effect of pressing the end of the separator 450 is high. As a result, the effect of suppressing the thermal contraction of the separator 450 or the effect of suppressing the entry of contamination is improved.

  Further, the spacer 600 including the side wall portion 620 is a member disposed inside the container 101. Therefore, after the spacer 600 and the electrode body 400 are accommodated in the container 101, the container 101 is filled with the electrolyte. That is, suppose that the copper contamination generated in the joining process of the composite material layer non-forming portion 421a and the negative electrode current collector 800 remains in the portion of the negative electrode plate 420 covered with the separator 450. However, the edge of the separator 450 is closed when the electrolyte is injected. Therefore, the copper contamination is confined in the space in the vicinity of the negative electrode plate 420, and as a result, the possibility of contact with the positive electrode plate 410 due to movement of the copper contamination in the electrolyte is reduced. Can do.

  Further, in power storage element 100 according to the present exemplary embodiment, convex portion 650 presses a position of electrode body 400 outside the positive electrode plate 410 in the X-axis direction when viewed from the side. That is, as shown in FIG. 6, the convex portion 650 is disposed outside the position Pb of the edge of the positive electrode plate 410 on the negative electrode side.

  According to this configuration, for example, the edges of the separator 450 are closed at a position before the positive electrode plate 410 when viewed from the mixture layer non-forming portion 421a. Thereby, for example, copper contamination generated in the joining process of the composite material layer non-forming part 421a and the negative electrode current collector 800 is difficult to reach a portion of the positive electrode plate 410 close to the composite material layer non-forming part 421a. Therefore, the occurrence of a fine short circuit due to the copper contamination coming into contact with the positive electrode plate 410 is suppressed.

  More specifically, in power storage device 100 according to the present embodiment, negative electrode plate 420 has composite material layer forming portion 424, and convex portion 650 is the X axis when viewed from the side of electrode body 400. The position where the composite material layer forming part 424 exists in the direction is pressed. That is, as shown in FIG. 6, the position Pb of the edge of the positive electrode plate 410 on the negative electrode side and the position Pd of the edge of the composite material layer forming portion 424 (the composite material layer forming portion 424 and the composite material layer non-forming portion). The convex portion 650 is disposed between the boundary position Pd) in the X-axis direction of 421a.

  Here, the composite material layer non-forming portion 421a joined to the negative electrode current collector 800 is a portion where the negative electrode base material layer 421 is exposed, and is a thin and soft portion. The convex portion 650 provided on the side wall portion 620 according to the present embodiment is a portion of the portion where the composite material layer forming portion 424 is laminated, which is inside the thin composite material portion 421a which is a thin and soft portion. Since the presence range is pressed from the side, the separator 450 can be pressed more firmly.

  Further, on the positive electrode side of the electrode body 400, as shown in FIG. 7, the convex portion 550 disposed on the side wall portion 520 of the spacer 500 is disposed so as to press the end portion of the separator 450. The thermal contraction of the separator 450 on the positive electrode side of 400 is suppressed.

  Specifically, the storage element 100 according to the present embodiment is a container 101 and an electrode body 400 accommodated in the container 101, and includes a negative electrode plate 420 and a positive electrode plate 410, and a negative electrode plate 420 and a positive electrode plate 410. The electrode body 400 formed by laminating the separator 450 disposed therebetween, the side wall portion 520 that is a side member disposed on the side of the electrode body 400 inside the container 101, and the positive electrode plate 410 And a positive electrode current collector 700 (see FIG. 2B) joined to a non-mixed material layer forming portion 411a. The negative electrode plate 420 has a composite material layer forming part 424, and the positive electrode plate 410 has a composite material layer forming part 414. The side wall part 520 has a long convex part 550 in a direction along the edge of the composite material layer non-forming part 411a of the separator 450. The convex portion 550 is a position where the composite material layer forming portion 424 is present and the composite material layer forming portion 414 is not present in the X-axis direction when viewed from the side of the electrode body 400 (Pb˜ in FIG. 7). Press any position of Pc).

  As described above, in the present embodiment, the side wall portion 520 of the spacer 500 has the long convex portion 550 along the edge of the separator 450, and the convex portion 550 is the positive electrode side of the electrode body 400. The end of the separator 450 can be pressed. Thereby, for example, the pressing force by the side wall portion 520 is efficiently applied to the end portion of the separator 450, and as a result, thermal contraction of the separator 450 on the positive electrode side of the electrode body 400 is suppressed. Moreover, since the convex part 550 presses the outer side (range in which the composite material layer non-formation part 411a exists) from the composite material layer formation part 414, the electrode body 400 was seen from the composite material layer non-formation part 411a side. In some cases, the separator 450 is pressed at a position before the composite material layer forming portion 414. Thereby, for example, copper contamination that moves in the electrolytic solution does not easily reach the composite material layer forming portion 414. As a result, the possibility of occurrence of defects due to copper contamination is reduced.

  Here, the composite material layer non-forming portion 411a joined to the positive electrode current collector 700 is a portion where the positive electrode base material layer 411 is exposed, and is a thin and soft portion. The convex part 550 provided in the side wall part 520 which concerns on this Embodiment is a compound material layer which is an inner side rather than the part on which only the compound material layer non-formation part 411a and the separator 450 which are this thin and soft part were laminated | stacked. The existence range of the portion where the forming portion 424 is laminated is pressed from the side. Therefore, on the positive electrode side of the electrode body 400 where ionization of copper contamination is likely to occur, the separator 450 is firmly pressed outside the composite material layer forming portion 414, and as a result, problems caused by copper contamination are more Suppressed reliably.

  In terms of positioning of the side wall 520, the spacer main body 510 included in the spacer 500 functions as an engaging portion that engages with the electrode body 400 or the positive electrode current collector 700 in the X-axis direction. In other words, in the present embodiment, the movement of the side wall portion 520 arranged on the side in the Y axis direction with respect to the electrode body 400 is restricted by the spacer main body portion 510 connected to the side wall portion 520. Thereby, for example, the convex portion 550 can be accurately positioned between Pb and Pc shown in FIG. This also applies to the spacer 600. That is, the spacer main body 610 included in the spacer 600 functions as an engaging portion that engages with the electrode body 400 or the negative electrode current collector 800 in the X-axis direction. In other words, the movement of the side wall portion 620 disposed on the side in the Y axis direction with respect to the electrode body 400 is restricted by the spacer main body portion 610 connected to the side wall portion 620 in the X axis direction. Thereby, for example, the convex portion 650 can be accurately positioned between Pb and Pd shown in FIG.

  Further, in the present embodiment, the spacer 500 is a position where the pair of convex portions 550 do not press the range in which the composite material layer forming portion 414 exists in the X-axis direction when viewed from the side of the electrode body 400 ( A pair of convex portions 550 are provided on the outer side of Pc in FIG. Similarly, in the spacer 600, the position where the pair of convex portions 650 do not press the range where the composite material layer forming portion 414 exists in the X-axis direction when viewed from the side of the electrode body 400 (Pb in FIG. 6). A pair of convex portions 650 on the outer side.

  That is, when the electrode body 400 is viewed from the side, each of the spacers 500 and 600 holds the separator 450 at a position outside the composite material layer forming portion 414 and the composite material layer forming portion 414 exists. Does not hold down the range. Therefore, the pressing force applied to the electrode body 400 by the spacers 500 and 600 can be efficiently used as a force for pressing the end of the separator 450. As a result, the thermal contraction of the separator 450 can be suppressed, or the possibility of occurrence of defects due to contamination can be reduced. In addition, for example, it is possible to prevent problems such as damage to the positive electrode plate 410 or the negative electrode plate 420 caused by the spacers 500 and 600 pressing the electrode body 400 excessively.

  The power storage element 100 according to the embodiment has been described above, but the power storage element 100 may include a spacer having a mode different from the modes illustrated in FIGS. Therefore, hereinafter, a modified example of the spacer included in the power storage element 100 will be described focusing on differences from the above embodiment.

(Modification 1)
FIG. 8 is a front view showing the configuration of the spacer 900 according to the first modification of the embodiment. In FIG. 8, the positional relationship between the side wall portion 920 of the spacer 900 and the electrode body 400 is schematically shown so that the feature of the spacer 900 is clear, and the side wall portion 920 is connected to the electrode body 400. It is shown away from. In FIG. 8, the approximate shape of the electrode body 400 is represented by a region with dots, and the approximate shape of the container 101 is represented by a dotted line.

  The power storage device 100a according to this modification includes a wound electrode body 400 having a flat shape in a direction orthogonal to the winding axis W, as described with reference to FIG. In the wound electrode body 400, the central portion in the Z-axis direction in FIG. 8 (intermediate portion between a pair of opposed curved portions) is likely to be recessed in the Y-axis direction. Therefore, the spacer 900 according to the present modification has a convex portion 950 having a shape in which the central portion in the longitudinal direction is raised on the side surface of the side wall portion 920 located on the side of the electrode body 400.

  That is, in this modification, the electrode body 400 is formed by winding the positive electrode plate 410, the negative electrode plate 420, and the separator 450 around the winding axis W, and the convex portion 950 is formed at the central portion in the longitudinal direction. The protruding amount is formed to be larger than other portions.

  According to this configuration, the central portion that is likely to be recessed in the wound electrode body 400 can be more reliably pressed by the convex portion 950 having a shape in which the central portion in the longitudinal direction protrudes from others. Specifically, when the density of the laminated body composed of the positive electrode plate 410, the negative electrode plate 420, and the separator 450 is compared between the curved portion and the intermediate portion of the wound electrode body 400, the laminated body is in a dense state in the curved portion. On the other hand, the laminated body is in a sparse state in the intermediate part. Therefore, the curved portion of the wound electrode body 400 is less likely to release the pressing force, and the intermediate portion is more likely to release the pressing force. That is, when the electrode body 400 is pressed from the side, the middle part of the electrode body 400 is easily recessed (easy to bend in the direction of the winding axis W).

  Therefore, the spacer 900 according to this modification has a convex portion 950 having a shape in which the central portion in the longitudinal direction is raised on the side surface of the side wall portion 920 in order to effectively press the electrode body 400. Thereby, for example, the effectiveness of the effect of pressing the separator 450 by the convex portion 950 of the side wall portion 920 is improved. Therefore, for example, the possibility that a gap between elements such as the separators 450 adjacent in the stacking direction is closed is improved, and as a result, the possibility of occurrence of defects due to contamination is reduced.

  Further, from the viewpoint of thermal contraction of the separator 450, as described above, the separator 450 is difficult to contract at the curved portion of the wound electrode body 400 because the laminated body including the separator 450 is in a dense state. On the other hand, since the laminated body including the separator 450 is in a relatively sparse state in the intermediate part (the central part in the Z-axis direction) of the wound electrode body 400, the separator 450 is easily contracted. With respect to the wound electrode body 400 having such a structural feature, the convex portion 950 has a shape in which the central portion protrudes, so that it can positively press the easily contracting portion of the separator 450. it can. As a result, the convex portion 950 of the spacer 900 can more reliably suppress the thermal shrinkage of the separator 450.

(Modification 2)
FIG. 9 is a diagram illustrating a configuration of the convex portion 660 included in the spacer 600a according to the second modification of the embodiment.

  The side wall portion 620 of the spacer 600 a according to this modification has a convex portion 660 that protrudes toward the electrode body 400. Unlike the convex part 650 which the spacer 600 which concerns on the said embodiment has, the convex part 660 which concerns on this modification is comprised by the part which protruded in two steps.

  Specifically, the convex portion 660 includes a first convex portion 660a and a second convex portion 660b having a smaller projection amount than the first convex portion 660a. The 1st convex part 660a presses the position inside the edge of the separator 450 in the X-axis direction when it sees from the side of the electrode body 400. As shown in FIG. The 2nd convex part 660b presses the position of the edge of the compound material layer formation part 414 in the X-axis direction at the time of seeing the electrode body 400 from the side.

  According to this configuration, for example, the separator 450 is formed in the projecting portion 660 in a state where the projecting portion 660 having the two-stage configuration is matched with the step generated at the edge position of the composite material layer forming portion 414 of the electrode body 400. Can be pressed firmly. Therefore, for example, suppression of thermal contraction of the separator 450 or suppression of contact with the composite material layer forming portion 414 of copper contamination can be further ensured.

(Other embodiments)
As described above, the power storage device according to the present invention has been described based on the embodiment and the modifications thereof. However, the present invention is not limited to the above-described embodiments and modifications. Without departing from the gist of the present invention, various modifications conceived by those skilled in the art may be applied to the above-described embodiment or modification, or a form constructed by combining a plurality of the constituent elements described above. It is included in the range.

  For example, the side member that presses the electrode body 400 from the side may be realized by means other than the spacer 500 or 600. For example, by providing long projections in the Z-axis direction at both ends in the X-axis direction of the plate-like member disposed along the side surface in the Y-axis direction of the electrode body 400, The end can be pressed.

  In addition, each of the convex portions 550 of the spacer 500 and the convex portion 650 of the 600 may not press the electrode body 400 directly. For example, when the insulating film is disposed along the outer periphery of the electrode body 400, each of the convex portion 550 and the convex portion 650 may press the electrode body 400 via the insulating film.

  Moreover, the side for pressing the end of the separator 450 on the negative electrode side of the electrode body 400 by arranging a long rod body in the Z-axis direction, for example, in any of the ranges of Pa to Pb in FIG. You may make it function as a member. The same applies to the positive electrode side, and an end of the separator 450 on the positive electrode side of the electrode body 400 is arranged by arranging a long rod body in the Z-axis direction, for example, in any of the ranges of Pb to Pc in FIG. You may make it function as a side member for pressing down.

  In addition, embodiments constructed by arbitrarily combining the constituent elements included in the above-described embodiment and its modifications are also included in the scope of the present invention. For example, the configuration of Modification 1 may be applied to Modification 2.

  The present invention can be applied to power storage elements such as lithium ion secondary batteries.

100, 100a Power storage element 101 Container 400 Electrode body 410 Positive electrode plate 411 Positive electrode base material layer 411a, 421a Composite material layer non-forming part 414, 424 Composite material layer forming part 420 Negative electrode plate 421 Negative electrode base material layer 450, 450a, 450b Separator 500 , 600, 600a, 900 Spacer 520, 620, 920, Side wall part 550, 650, 660, 950 Protruding part 700 Positive electrode current collector 800 Negative electrode current collector

Claims (6)

A container,
An electrode body housed in the container, the electrode body formed by laminating a negative electrode plate and a positive electrode plate, and a separator disposed between the negative electrode plate and the positive electrode plate;
Inside the container, a side member disposed on the side of the electrode body,
A conductive member joined to a negative electrode end that is an end of the negative electrode plate,
The side member is a convex portion that presses a position on the inner side of an edge of the separator on the negative electrode end side when viewed from the side of the electrode body, and the end of the separator. It has a long convex part in the direction along the edge,
Power storage element. The convex portion presses a position outside the positive electrode plate when viewed from the side of the electrode body,
The power storage device according to claim 1. The negative electrode plate has a negative electrode mixture layer forming part,
The convex portion presses a position where the negative electrode mixture layer forming portion exists when viewed from the side of the electrode body,
The electricity storage device according to claim 2. A container,
An electrode body housed in the container, the electrode body formed by laminating a negative electrode plate and a positive electrode plate, and a separator disposed between the negative electrode plate and the positive electrode plate;
Inside the container, a side member disposed on the side of the electrode body,
A conductive member joined to a positive electrode end that is an end of the positive electrode plate;
The negative electrode plate has a negative electrode mixture layer forming part,
The positive electrode plate has a positive electrode mixture layer forming part,
The side member has a long convex portion in a direction along the edge on the positive electrode end side of the separator,
The convex portion, when viewed from the side of the electrode body, presses the position where the negative electrode mixture layer forming portion is present and the positive electrode mixture layer forming portion is not present,
Power storage element. The side member has the convex portion at a position where the convex portion does not press the range where the positive electrode mixture layer forming portion exists when viewed from the side of the electrode body.
The electrical storage element as described in any one of Claims 1-4. The electrode body is formed by winding the negative electrode plate, the positive electrode plate and the separator around a winding axis,
The protrusion is formed such that the protruding amount of the central portion in the longitudinal direction is larger than other portions.
The electrical storage element as described in any one of Claims 1-5.

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