JP5125053B2 - Flat electrochemical cell and assembled battery comprising the same - Google Patents

Description

  The present invention relates to a flat electrochemical cell and an assembled battery.

The flat electrochemical cell is configured by sealing and storing a power storage unit including an electrode and an electrolyte, such as a lithium ion battery, a capacitor, and a capacitor. For example, a lithium ion battery includes a liquid, gel-like, or polymer-like electrolyte, and a positive electrode / negative electrode active material made of a polymer. In this lithium ion battery, the lithium atom (Li) in the lithium transition metal oxide, which is the positive electrode active material, is charged as lithium ion (Li ⁺ ) during charging and enters the carbon layer of the negative electrode (intercalation). This is a battery in which charge / discharge reaction proceeds when ions (Li ⁺ ) are desorbed (deintercalated) from the carbon layer and moved to the positive electrode to become the original lithium compound.

  Here, the configuration of the lithium ion battery is composed of a positive electrode current collector / positive electrode active material layer / electrolyte layer / negative electrode active material layer / negative electrode current collector and an outer package that wraps them, and the outer package includes at least a base material layer, It consists of a metal foil and a heat-adhesive resin layer.

  FIG. 17A is a perspective view of the embossed type lithium ion battery 1, and as shown in FIG. 17B, lithium ion is used by using the outer package 5 including the tray 5t and the sheet 5s on which the embossed portion is formed. The battery body 2 is hermetically stored. Reference numeral 4 denotes a tab (metal terminal) connected to the positive electrode and the negative electrode of the lithium ion battery body 2.

  By the way, an attempt has been made in recent years to ensure a predetermined output by combining a plurality of lithium ion batteries 1 enclosed in an exterior body and to use the lithium ion battery 1 as a power source of a hybrid vehicle or an electric vehicle. However, in order to be mounted on the vehicle body and used for a long time, it is necessary to reduce the size of the lithium ion battery to increase the output per volume of the lithium ion battery and to have sufficient vibration resistance and heat dissipation against the shaking of the vehicle body during traveling. .

Conventionally, as a method for solving these problems, a method has been proposed in which a plurality of flat lithium ion batteries are housed and arranged in parallel using frame bodies having various shapes as shown in Patent Documents 1, 2, 3, and 4. It was.
JP 2005-197179 A JP 2006-156185 A JP 2005-122925 A JP 2005-302501 A

  However, each of these frames has a structure in which the outer periphery of the outer casing is pressed and sandwiched by a set of peripheral edges of the frame, and the peripheral edge of the frame forms a surface of a predetermined region. It was necessary to provide a large frame. Further, there is a problem that external vibration is weak against horizontal vibration with respect to the sandwiched surface.

  Therefore, in view of the above problems, the present invention provides a flat electrochemical cell that further reduces the overall volume of a flat electrochemical cell such as a lithium ion battery supported by a frame and is excellent in vibration resistance and heat dissipation. The purpose is to do.

  In order to achieve the above object, the configuration of the present invention encloses a power storage unit including a positive electrode, a negative electrode, and an electrolyte filled between the positive electrode and the negative electrode in an outer package made of a laminate having a seal layer as an innermost layer. A flat electrochemical cell having a heat-sealed peripheral edge of the outer package is housed in a box-shaped first frame body having a side wall extending vertically from a lower surface plate and a peripheral edge of the lower surface plate; A flat type characterized in that the outer periphery of the exterior body is folded back to the outer peripheral side of the side wall of the body, and is closed with a box-shaped second frame body in which the side wall is vertically suspended from the upper surface plate and the periphery of the upper surface plate. It is an electrochemical cell.

  The present invention is characterized in that, in the outer peripheral portion of the flat electrochemical cell having the above-described configuration, the vicinity of the region in contact with the upper surface of the side wall of the first frame is an unsealed region.

  According to the present invention, in the flat electrochemical cell having the above-described configuration, a resin portion is provided on at least one of the side wall portion of the first frame body or the inner periphery of the side wall portion of the second frame body that comes into contact with the peripheral edge portion of the exterior body. Features.

  In the flat electrochemical cell having the above-described configuration, when a plurality of flat electrochemical cells are overlapped, a convex shape that engages the lower plate and the upper plate of adjacent flat electrochemical cells. A plurality of sets of engaging portions are provided on the lower surface plate and the upper surface plate.

  In the flat electrochemical cell having the above-described configuration, the present invention is characterized in that openings are provided in the lower surface plate and the upper surface plate.

  In the flat electrochemical cell having the above-described configuration, a safety valve for releasing gas generated inside the exterior body to the outside of the exterior body is provided at the periphery of the exterior body, and the safety valve has a predetermined gas pressure inside the exterior body. A valve portion that opens when the value is exceeded, a housing portion that houses the gas and electrolyte that has passed through the valve portion, and a gas permeable portion that allows only gas to permeate from the housing portion, and the housing portion is a peripheral edge of the exterior body It is an unsealed region provided in a part of the portion, and the gas permeable portion is a polymer sheet that closes an exterior body opening formed on the unsealed region.

  In the flat electrochemical cell having the above-described configuration, the present invention is characterized in that the polymer sheet is a porous fluororesin sheet.

  In the flat electrochemical cell having the above-described configuration, the present invention is characterized in that the porous fluororesin sheet is a stretched porous polytetrafluoroethylene sheet.

  In the flat electrochemical cell having the above-described configuration, the valve portion is configured by sandwiching the outer periphery of the exterior body between the side wall portion of the first frame body and the upper surface plate.

  The present invention is an assembled battery comprising a combination of a plurality of flat electrochemical cells having the above structure.

  According to the first configuration of the present invention, when the flat electrochemical cell is accommodated in the first frame, the outer periphery of the outer frame is folded back on the outer periphery of the side wall of the first frame, and the outer frame is closed by the second frame. By folding the peripheral edge of the body, the flat electrochemical cell can be accommodated in the frame more compactly. As a result, it is possible to secure a wide outer peripheral edge, provide a wide heat seal area, and improve the sealing strength over time. Moreover, since the outer periphery of the outer body is folded back to the outer periphery of the side wall of the first frame, the outer periphery of the outer body is the upper surface of the side wall of the first frame and the upper surface of the second frame when closed by the second frame. The flat electrochemical cell sandwiched between the plates is securely held by the frame. In addition, by pressing the sandwiched region from above and below, vibration resistance and delamination of the heat seal layer that occurs in the outer periphery of the outer casing by generating gas inside the outer casing of the flat electrochemical cell and expanding the outer casing. Can be prevented.

  According to the 2nd structure of this invention, the part contact | abutted with the side wall part of a 1st frame corresponds to the fold which turned up the exterior body peripheral part. For this reason, when the outer body is heat-sealed and then bent with excessive addition to this portion, there is a high possibility that a short circuit will occur due to cracking. However, cracking does not occur even when bent by making this part an unsealed region, and a short circuit can be prevented.

  According to the 3rd structure of this invention, by providing a resin part in at least any one of the side wall part outer periphery of the 1st frame body which contact | abuts an outer peripheral body peripheral part, or the side wall part inner periphery of a 2nd frame body, The flat electrochemical cell can be more closely held by the body and the second frame. Thereby, a frame can hold | maintain a flat type electrochemical cell stably, and can improve vibration resistance further.

  According to the fourth configuration of the present invention, a plurality of flat electrochemical cells can be accommodated by providing convex engaging portions respectively corresponding to the lower surface plate of the first frame body and the upper surface plate of the second frame body. By engaging with the engaging portion, a plurality of flat electrochemical cells can be combined and easily packaged. Moreover, since the shape of the engaging portion is convex, a gap is generated between adjacent flat electrochemical cells when engaged. As a result, even when the flat electrochemical cell generates heat, it is possible to ensure a certain heat dissipation property by ventilation from the gap.

  According to the fifth configuration of the present invention, the surface of the exterior body is exposed to the outside by the opening provided in the frame body in the gap between the adjacent flat electrochemical cells formed by the convex engaging portion. . Thereby, the heat dissipation effect from a flat type electrochemical cell can be heightened further.

  According to the sixth configuration of the present invention, in the safety valve provided at a part of the peripheral portion of the exterior body, when the gas pressure inside the exterior body exceeds a predetermined value, the valve portion opens, and once the gas and the electrolyte are supplied. After being guided to the storage part, only the gas is discharged from the gas transmission part to the outside of the exterior body.

  In addition, when the gas pressure inside the exterior body does not exceed a predetermined value, even if water vapor permeates the gas permeation part and enters the accommodation part, the valve part is closed, so that the storage part can enter the exterior body. Intrusion of water vapor is blocked.

  In this way, by providing a storage portion between the exterior body exterior and the exterior body exterior, the gas tightness inside the exterior body is ensured by the valve portion while the gas pressure is constant, and the entry of water vapor from the outside is prevented. Can do. Also, after the gas pressure rises and the valve part opens, the gas and electrolyte once flow into the storage part, and then the gas is permeated. it can.

  Moreover, since the said accommodating part is an unsealed area | region provided in the outer periphery part of the exterior body, it can be easily formed at the time of heat sealing, and the gas permeable part can be formed by simply attaching a polymer sheet to the exterior body opening. Since it can form, manufacturing cost can be held down.

  According to the 7th structure of this invention, the function which does not permeate | transmit only gas and permeate | transmitting liquids, such as an electrolyte, can be easily provided by comprising a gas permeation | transmission part with a porous fluorine resin sheet.

  According to the eighth configuration of the present invention, the gas permeable portion is formed of a polytetrafluoroethylene sheet having a stretched porous structure, thereby exhibiting excellent gas permeability, and the gas generated inside the exterior body In addition to being released to the outside and being excellent in water repellency, it is possible to block the liquid that tries to enter from the exterior of the exterior body and the electrolyte that leaks from the interior of the exterior body to the exterior. Further, by adjusting the hole diameter and the porosity of the sheet by a stretching method, it is possible to select optimum characteristics as the gas permeable portion according to the present invention.

  Moreover, since polytetrafluoroethylene is excellent also in heat resistance, chemical resistance, and toughness, even when a high-temperature electrolyte adheres, it can continuously exhibit gas permeability without deterioration.

  According to the 9th structure of this invention, a valve | bulb part can be easily formed by pinching | interposing an outer peripheral body peripheral part with the side wall part of a 1st frame, and the upper surface board of a 2nd frame.

  According to the 10th structure of this invention, the assembled battery which is excellent in high output and safety | security can be provided by comprising an assembled battery combining the said flat electrochemical cell.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings using a lithium ion battery which is a kind of flat electrochemical cell. The flat electrochemical cell includes a pouch type and an embossed type depending on the type of the outer package that wraps the power storage unit, and the present invention can be applied to any type. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 17 of a prior art example, and description is abbreviate | omitted.

  1A is a schematic perspective view of the lithium ion battery 1 before the frame body is mounted, and FIG. 1B is a schematic cross-sectional view taken along line x-x ′ of FIG. The lithium ion battery 1 heat seals the outer periphery 5a of the exterior body, and the lithium ion battery body 2 is hermetically housed inside. Moreover, although the rectangular exterior body is normally used, since this lithium ion battery 1 needs to mount | wear with a frame, the corner is cut off after heat sealing.

  Here, the lithium ion battery body 2 includes a positive electrode composed of a positive electrode active material and a positive electrode current collector, a negative electrode composed of a negative electrode active material and a negative electrode current collector, and an electrolyte filled between the positive electrode and the negative electrode (both A cell (power storage unit) including a cell (not shown) and a tab (electrode terminal) 4 that is connected to a positive electrode and a negative electrode in the cell and protrudes to the outside of the outer package 5. The tab 4 connected to the positive electrode and the negative electrode is made of metal, and a combination of a plurality of lithium ion batteries 1 and the tabs 4 connected in series can be used as a high output power source device.

  In addition, a safety valve 6 is provided on a part of the outer periphery 5a of the exterior body, and has a function of releasing the gas generated inside the exterior body to the outside. The inside of the exterior body is closed until the pressure inside the exterior body reaches a predetermined value to ensure airtightness, and once the internal pressure exceeds the predetermined value, the gas is released to the outside of the exterior body to reduce the internal pressure. Prevents the bursting. The specific configuration of the safety valve 6 will be described in detail later.

  FIG. 2 is a schematic perspective view of the lithium ion battery 1 when the frame body is mounted according to the present invention, and FIG. 3 is a schematic perspective view showing the lithium ion battery 1 in a state where the frame body is disassembled. FIG. 4 is a schematic perspective view showing a state in which the lithium ion battery 1 is housed in the first frame 10.

  As shown in FIG. 3, the frame is composed of a first frame 10 and a second frame 11 having a storage space for the lithium ion battery 1, and the first frame 10 has a side wall 10a suspended from the periphery of the lower surface plate 10d. In addition to forming a storage space for the lithium ion battery 1, the lower surface plate 10d is provided with an opening 10c and an engaging portion 10b. Similarly, the second frame 11 has a side wall portion 11a suspended from the periphery of the upper surface plate 11d, and the upper surface plate 11d is provided with an opening 11c and an engaging portion 11b.

  As shown in FIG. 4, first, the lithium ion battery 1 is stored in the storage space of the first frame 10, and the outer peripheral edge 5a protruding from the first frame 10 is attached to the side wall of the first frame. It folds to the outer peripheral side of the part 10a and covers the second frame 11 from above and is attached.

  FIG. 5A is a schematic cross-sectional view of the lithium ion battery 1 equipped with the frame in AA ′ of FIG. 2. The first frame 10 and the second frame 11 are attached to the lithium ion battery 1 with the above structure. When mounted, the outer peripheral edge 5a of the lithium ion battery 1 is sandwiched between the upper peripheral edge of the side wall 10a of the first frame and the upper surface plate 11d of the second frame, and the remaining part is the side wall of the first frame. It is accommodated between 10a and the side wall part 11a of the second frame. Thereby, it is possible to secure a sufficient area in the outer periphery 5a of the outer package and heat-seal it, to improve the sealing performance inside the outer package, and to store the lithium ion battery 1 compactly in the frame. it can. Further, the lithium ion battery 1 can be stably held in the frame, and the vibration resistance is excellent.

  Specifically, the entire lithium ion battery 1 is sandwiched between the first frame lower surface plate 10d and the second frame upper surface plate 11d with respect to the vertical vibration, and the exterior body peripheral portion 5a with respect to the horizontal vibration. Is bent and hooked on the side wall portion 10a of the first frame body, and the outer peripheral edge portion 5a is sandwiched between the side wall portion 10a of the first frame body and the upper surface plate 11d of the second frame body. Excellent vibration resistance.

  Here, the lithium ion battery is more stably held in the frame body by holding the first frame body 10 and the second frame body 11 with a certain pressure. In addition, when gas is generated inside the exterior body and the exterior body expands, delamination may occur near the boundary between the exterior body peripheral edge 5a and the interior of the exterior body, but the side wall 10a and the upper surface plate 11d Occurrence of delamination can be prevented by pressing and holding the outer periphery 5a of the outer package. Further, when the lithium ion battery 1 is held in the frame with the above structure, the shape of the frame may be simple, and the frame according to the present invention is excellent in terms of production efficiency.

  FIG. 5B is a schematic cross-sectional view of the frame when the resin portion 10e is provided on the periphery of the side wall portion 10a of the first frame body and the resin portion 11e is provided on the inner peripheral side of the side wall portion 11a of the second frame body. FIG. 5C is a schematic cross-sectional view when the frame body provided with the resin portion is attached to the lithium ion battery 1. As described above, by providing the resin portions 10e and 11e, the resin portion serves as a buffer material, and the lithium ion battery 1 can be more stably held inside the frame body and the vibration resistance can be improved. In the figure, the resin portion is provided only on the side wall portion 10a of the first frame body and the side wall portion 11a of the second frame body, but the lower surface plate 10d of the first frame body 10 and the upper surface plate of the second frame body 11 are also provided. Even if a resin portion is provided at 11d, further improvement in vibration resistance can be expected. Further, when a resin part having adhesiveness is used, the vibration resistance is further improved.

  FIGS. 6A and 6B are schematic cross-sectional views enlarging a portion surrounded by a broken line in FIG. Note that the second frame 11 is omitted for simplicity of explanation. The outer peripheral portion 5a is folded back to the outer peripheral side with the fold as the portion that contacts the side wall portion 10a of the first frame. At this time, since the fold is further sandwiched between the side wall 10a and the upper surface plate 11d of the second frame, there is a high possibility that a crack will occur in the heat seal layer of the outer periphery 5a and a short circuit will occur.

  Therefore, in this embodiment, in the outer periphery 5a of the exterior body, the vicinity of the portion that comes into contact with the side wall 10a of the first frame that is a crease is defined as an unsealed region, and cracks in the heat seal layer in the region and the occurrence of short circuit due to this are prevented. It is out.

  FIG. 7A is a schematic perspective view of the second frame 11, and FIG. 7B is a schematic perspective view showing the back surface of the first frame 10. The first engagement portion 10b provided on the first frame body 10 and the second engagement portion 11b provided on the second frame body 11 are engaged in a pair. In FIGS. 7A and 7B, the first engaging portion 10b and the second engaging portion 11b are both L-shaped, and the second engaging portion 11b is disposed on the peripheral side of the first engaging portion 10b. The engaging portion is not necessarily L-shaped, and the arrangement of the engaging portions is not limited as long as both frame bodies are engaged and fixed at predetermined positions.

  Further, the lower surface plate 10d and the upper surface plate 11d have openings 10c and 11c, respectively, and the exterior surface of the lithium ion battery 1 is exposed to the outside when the frame is mounted.

  FIG. 7C is a schematic perspective view of an assembled battery 12 in which a plurality of lithium ion batteries 1 mounted with the frame are stacked. When stacking the lithium ion batteries 1, as described above, the engaging portions 10 b of the first frame body 10 and the engaging portions 11 b of the second frame body of the adjacent lithium ion batteries 1 are engaged and fixed. The lithium ion battery 1 can be easily packaged.

  Moreover, since these engaging parts are convex, at the time of engagement, a clearance gap is produced between adjacent frame bodies by the thickness of the engaging part. Thereby, when the lithium ion battery 1 generates heat, a certain air permeability is secured through the openings 10c and 11c of the frame body and the gap, and a heat dissipation effect is obtained.

  FIG. 8 is a schematic perspective view of the second frame 11, and it is possible to improve the strength of the frame by providing the opening 11c with the reinforcing portion 11g having the rib 11f. At this time, the first frame 10 also needs to have a similar structure so as to overlap with the ribs 11f of the second frame 11.

  Next, the lithium ion battery 1 with a safety valve will be described. FIG. 9 is a schematic perspective view showing the lithium ion battery 1 according to the present invention in an exploded manner. The exterior body used in the lithium ion battery 1 according to the present invention is a tray having a predetermined region on one side of the exterior body peripheral edge 5a. The lithium ion battery main body 2 is accommodated using a sheet 5s having a size corresponding to 5t. Moreover, the opening part 7b is provided in the sheet | seat 5s, and the gas permeation | transmission part 7 (refer FIG. 1) is formed by closing with the polymer sheet 7a. At this time, the polymer sheet 7a itself does not need to have adhesiveness, and the opening portion without covering the function of the polymer sheet 7a can be obtained by covering the polymer sheet 7a from above with the adhesive sheet 7c having an opening near the center. 7b can be blocked. The polymer sheet 7a is not limited to being attached from the upper surface of the sheet 5s, and may be attached from the lower surface of the sheet 5s.

  The storage portion 8 (see FIG. 1) is formed by providing an unsealed region when heat sealing the outer periphery portion 5a. Here, although it is necessary to consider the size of the lithium ion battery 1 as a whole, the storage portion 8 is not provided as a passage from the valve portion 9 (see FIG. 1) to the gas permeation portion 7 but flows from the valve portion 9. In order to temporarily store the gas and electrolyte to be stored, it is desirable to provide as large as possible. That is, when the storage unit 8 has a certain capacity, even if the gas pressure inside the exterior body suddenly increases, the increase in gas pressure is moderated to some extent by the storage unit 8 to prevent the exterior body from bursting. Can do.

  The valve portion 9 is sealed in a state of being sandwiched by the exterior body 5 up and down, and the interior of the exterior body keeps high confidentiality until the internal pressure reaches a predetermined value, and also against the intrusion of water vapor from the outside. High barrier properties.

  A blend resin of polypropylene (hereinafter abbreviated as PP) and polyethylene (hereinafter abbreviated as PE) is preferably used as the base material constituting the valve portion 9. PP can lower the seal strength compared to pure PP by blending PE. Therefore, by using a PP layer for the heat seal layer of the exterior body and using the blended resin at a location where the valve portion 9 is to be provided, the internal pressure of the exterior body rises and pressure is applied to peel off the exterior body upper surface and the exterior body lower surface. When this occurs, the seal portion of this blend resin can be peeled off preferentially.

  Thereby, gas can be made to flow in from the valve part 9 to the accommodating part 8, and gas can be discharge | released outside from the gas permeation | transmission part 7 before the other exterior body peripheral part 5a peels.

  However, when the sealing strength between the valve portion 9 and the outer casing 5 is too low, the airtightness inside the outer casing 5 is not ensured, and the invasion of vapor from the outside tends to occur. Moreover, when the sealing strength of the valve part 9 is too high, the valve part 9 may be aggregated and destroyed in a state where the pressure inside the exterior body becomes considerably high, and the gas permeable part 7 may be destroyed by the impact. Therefore, it is necessary to use a blend resin having a suitable strength by adjusting the constituent ratio of PP and PE for the valve portion 9. Further, the valve portion 9 preferably has a shape in which the tip protrudes to the inside of the exterior body in order to be peeled off before the seal portion of the exterior body peripheral portion 5a when the internal pressure increases. .

  Moreover, it is also possible to comprise the valve part 9 using the said frame. As described above, the lithium ion battery 1 according to the present invention has a structure in which the outer peripheral edge 5a is sandwiched between the side wall 10a of the first frame 10 and the upper surface plate 11d of the second frame 11 when the frame is mounted. (See FIG. 5A). Therefore, when a predetermined region of the outer peripheral edge portion 5a forming the valve portion 9 is sandwiched by using a frame body with a constant pressure, the frame body serves as the valve portion and ensures airtightness inside the outer casing body 5. To do. Further, when the internal pressure reaches a certain value or more, the exterior body expands due to the generation of gas, and the region in which the second frame 11 is detached from the first frame 10 and is held open. As a result, the gas flows into the accommodating portion 8 and is released from the gas permeable portion 7 to the outside.

  Further, when the valve portion 9 is configured in such a configuration, the internal pressure when the valve portion is opened can be adjusted to some extent by pressing the frame body that sandwiches the outer peripheral edge portion, and the resin portions 10e and 11e are The airtightness inside the exterior body can be further improved by sandwiching the exterior body periphery 5a by the provided frame body (see FIG. 5C).

  Next, the polymer sheet 7a constituting the gas permeable part 7 will be described. The polymer sheet 7a is made of polytetrafluoroethylene (hereinafter abbreviated as PTFE) having a stretched porous structure. PTFE itself is composed of only carbon and fluorine, and has a very strong bonding force between fluorine atoms and carbon atoms, and a low polarizability and intermolecular force. Therefore, compared to ordinary plastics, heat resistance, chemical resistance, and toughness It is extremely excellent.

  As a result, the gas pressure inside the exterior body increases due to overcharge and the like, and even when the electrolyte is heated to a high temperature, the resin sheet in the gas permeable portion 7 does not thermally deteriorate, and the organic sheet such as the electrolyte does not deteriorate. Has stability.

  Moreover, since PTFE has a porous structure, only gas can permeate | transmit and liquids, such as an electrolyte, can be interrupted | blocked. At this time, since PTFE can freely control the porosity and the hole diameter by the stretching method, the polymer sheet 7a used for the gas permeable portion according to the present invention can be controlled by controlling the porosity and the hole diameter. Optimal characteristics can be selected.

  Note that when the porosity of the porous film increases, the water repellency decreases and the gas permeability increases. Further, the smaller the hole diameter, the higher the water repellency and the lower the gas permeation.

  Next, the seal area and shape of the lithium ion battery 1 exterior body with a safety valve will be described in detail. 10 (a) is a perspective view showing the lithium ion battery 1 according to the present invention from above, FIG. 10 (b) is a perspective view showing the back surface of the lithium ion battery 1, and FIG. 11 is FIG. 10 (a). It is a front view of the lithium ion battery 1 with a safety valve shown in FIG.

  In the lithium ion battery 1, a lithium ion battery main body 2 is housed in a tray 5t formed by press molding, a sheet 5s is covered, the outer periphery 5a of the exterior body is heat sealed, and the inside is sealed. At this time, an opening is provided in a part of the exterior body, and the gas permeable portion 7 is formed by closing the opening with a gas permeable polymer sheet. Further, when the lithium ion battery 1 is housed in the first frame body 10 and the outer peripheral edge portion 5a is bent to the outer peripheral side of the side wall portion 10a of the first frame body and closed with the second frame body 11, the frame body An exterior body is clamped and a valve part is formed.

  Further, FIG. 11 shows the heat seal region R and the crease q of the exterior body, but the vicinity of the crease q is not heat sealed, and when the exterior body is folded and stored in the frame body, cracks are formed in this portion. Is prevented from occurring.

  Further, when the exterior body is folded back along the crease q, the vicinity of the exterior body top portion p is a portion where stress is most easily applied, and therefore, there is a high possibility that cracks and pinholes are generated in the inner layer near this portion.

  However, since the corner 5b of the tray 5t is chamfered, a predetermined area is secured between the apex p and the corner 5b. Therefore, by heat-sealing this region, it is possible to prevent the cracks or pinholes from entering the exterior body even if cracks or pinholes are generated at the apex p.

  By taking the heat seal region and the exterior body shape as described above, the safety of the lithium ion battery can be further improved when the frame body is mounted.

  Next, the manufacturing method of the lithium ion battery 1 with a safety valve shown in FIG. 10 is demonstrated. Since gas such as hydrogen and oxygen is usually generated in the charge / discharge reaction of the battery, the lithium ion battery 1 in which the exterior body is sealed may expand and rupture due to an increase in gas pressure inside the exterior body. However, as shown in FIG. 10, by providing the gas permeable portion 7 at a part of the outer periphery 5a of the outer casing, the gas generated inside the outer casing is released to the outside, and the gas pressure inside the outer casing is kept constant. Can do. However, since the battery generates a particularly large amount of gas during the initial charging, it is necessary to commercialize the lithium-ion battery 1 after performing the initial charging and degassing in advance.

  FIG. 12 is a diagram showing a manufacturing process of the lithium ion battery 1 provided with a gas permeable portion. First, a gas permeable polymer seal 7a is attached to the exterior body opening portion attached from the inside of the exterior body. A non-functional barrier seal 7d is attached from the outside of the outer package. As a result, the opening is temporarily closed.

  Next, after injecting an electrolyte into the exterior body from the injection port (see the arrow in FIG. 12A), the injection port is heat-sealed to seal the inside (see FIG. 12B). At this time, since the opening is temporarily closed by the barrier seal 7d, water vapor does not enter the exterior body. Next, the battery body 2 is initially charged. At this time, gas is generated inside the exterior body, and the interior of the exterior body expands and the internal pressure increases (see FIG. 12C).

  Next, after the initial charging, the exterior body is allowed to stand for a predetermined time at a constant temperature, and after aging until gas generation has settled, the periphery of the opening is evacuated, the barrier seal 7d is peeled off, and the gas inside the exterior body is removed. Release to the outside (see FIG. 12D). At this time, since the periphery of the opening is in a vacuum state, water vapor does not enter the exterior body from the opening 7b. In addition, before peeling off the barrier seal 7d, the exterior body may be sandwiched by a frame body, and after securing the inside of the exterior body, it may be peeled off. According to this method, since the hermeticity inside the exterior body is ensured, it is not necessary to make the periphery of the opening in a vacuum state. Moreover, you may peel off so that the barrier seal | sticker 7d may be blown off using an internal gas pressure.

  Here, after all the gas inside the exterior body has been released, the lithium ion battery 1 is completed (see FIG. 12E). Thus, by using the gas permeable part 7, the gas generated at the time of initial charging can be efficiently discharged to the outside of the exterior body, and the manufacturing efficiency of the battery is improved.

  Next, the assembled battery 12 combining the lithium ion battery 1 with a safety valve shown in FIG. 10 will be described in detail. FIG. 13A is a cross-sectional view when the frame is attached to the lithium ion battery 1, and FIG. 13B is a front view of the lithium ion battery 1 for explaining the configuration of the safety valve 6. The valve portion 9 of the safety valve is configured by sandwiching the outer periphery of the exterior body between the side wall portion 10a of the frame body and the upper surface plate 11d. The sealability is ensured and the valve function cannot be exhibited.

  FIG. 14A is a schematic diagram showing the assembled battery 12. The lithium ion battery 1 with a safety valve is connected to a plurality of batteries by attaching the first frame body 10 and the second frame body 11, and has a high output. The assembled battery 12 can be easily packaged. Here, the assembled battery 12 is housed between two support plates 14 fixed to a predetermined width by four screws 15, and the battery 1 is pressed directly from an opening provided at the center of both support plates 14. Thus, the entire battery is sandwiched. Therefore, the support plate 14 and the battery 1 are not in contact.

  FIG. 14B is a cross-sectional view specifically showing a method of sandwiching the assembled battery 12. A spring 16 is provided in the opening of the support plate 14, and a support portion 17 for supporting the spring 16 is a support plate 14. It is provided above. Thereby, the assembled battery 12 can be clamped from right and left by appropriate pressing using the elastic force of the spring 16. Here, the appropriate pressure is generated inside the exterior body, and gas can flow out from the valve portion 9 to the gas storage portion 8 when the internal pressure increases, and when the internal pressure decreases after gas release, the gas permeable portion. 7 refers to a pressure that does not allow water vapor flowing from 7 to enter the exterior body. The elastic force of the spring can automatically release the gas and seal the inside of the exterior body. Note that. Although the spring is used in this embodiment, an elastic body such as rubber or synthetic resin may be used instead of the spring.

  A connector 13 is used to connect each battery 1. FIG. 15A is a perspective view of the connector 13, and FIG. 15B is a cross-sectional view taken along x-x ′. The connector 13 connects adjacent batteries 1 and is a rectangular parallelepiped having both ends opened in a slit shape. Also, a clip-type terminal 13c is provided inside, and a conductive material 13b such as copper formed on the inner surface is connected to the clip-type terminal 13c. With this configuration, by inserting the metal terminal 4 of the adjacent battery 1 into the opening of the connector 13 from both ends, the metal terminal 4 is locked by the clip-type terminal 13c, and both the metal terminals 4 are connected via the conductive material 13b. Connected. At this time, by configuring the outer surface of the connector 13 with an insulating resin, it is possible to prevent an electric shock by touching the portion when the battery is used.

  FIG. 16 is a perspective view of the lithium ion battery 1 that specifically shows a method of mounting the connector 13. By alternately connecting the positive electrode metal terminals 4a and the cathode metal terminals 4b as shown in the figure, a plurality of batteries 1 can be connected in series, and a high output can be obtained.

  Conventionally, as a connecting method of the battery 1 constituting the assembled battery 12, the metal terminal 4 and the conductive wire are fixed or welded with a screw or the like, but the battery is incorporated into the assembled battery 12 by using the connector 13. A battery can be easily connected. For this reason, for example, when one battery fails, only the failed battery can be easily replaced.

  As described above, the present invention is not limited to the above-described embodiments, and various modifications are possible. Embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the present invention. Included in the technical scope. In addition to the lithium ion battery, the frame according to the present invention can be used in a flat electrochemical cell that is hermetically sealed in an outer package such as a capacitor or a capacitor.

  INDUSTRIAL APPLICABILITY The present invention can be used for a durable and safe lithium ion battery suitable as a power source for energy storage and electric vehicles.

FIG. 3 is a perspective view of a lithium ion battery before the frame body is mounted. FIG. 3 is a perspective view of a lithium ion battery when the frame is mounted. FIG. 3 is a perspective view showing a lithium ion battery in a state where a frame body is disassembled. FIG. 3 is a perspective view showing a state in which a lithium ion battery is housed in a first frame. FIG. 3 is a cross-sectional view of a lithium ion battery equipped with a frame body in A-A ′ of FIG. 2. These are sectional drawings to which the location enclosed with the broken line of Fig.5 (a) was expanded. (A) A perspective view of the 2nd frame, (b) A perspective view showing the back of the 1st frame, (c) A perspective view of an assembled battery. FIG. 3 is a perspective view of a second frame. FIG. 3 is an exploded perspective view showing a lithium ion battery. (A) is a perspective view showing a second example of the lithium ion battery according to the present invention, (b) is a perspective view showing the back surface of the lithium ion battery, FIG. 11 is a front view of the lithium ion battery shown in FIG. These are sectional drawings which show the manufacturing process of the battery with a safety valve which concerns on this invention. (A) It is sectional drawing which shows the structure of a safety valve when the battery with a safety valve which concerns on this invention is mounted | worn to a frame, (b) It is a front view. (A) is a perspective view of a battery pack according to the present invention, (b) is a cross-sectional view. These are (a) a perspective view of a connector and (b) a sectional view. These are perspective views which show the connection method of a lithium ion battery. These are a perspective view and an exploded perspective view of a conventional lithium ion battery (embossed type).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lithium ion battery 2 Lithium ion battery main body 4 Metal terminal 5 Exterior body 5a Outer body peripheral part 5t Tray 5s Sheet 6 Safety valve 7 Gas permeation part 7a Polymer sheet 7b Opening part 8 Storage part 9 Valve part 10 1st frame 10a Side wall Part 10b Engagement part 10c Opening part 10d Lower surface plate 10e Resin part 11 Second frame 11a Side wall part 11b Engagement part 11c Opening part 11d Upper surface part 11e Resin part 11f Rib 11g Reinforcement part 12 Battery assembly 13 Connector 14 Support plate 15 Screw 16 Spring 17 Support part

Claims (9)

A power storage unit including a positive electrode, a negative electrode, and an electrolyte filled between the positive electrode and the negative electrode is enclosed in an outer package made of a laminate in which a seal layer is laminated on the innermost layer, and the peripheral portion of the outer package is heat sealed. A flat electrochemical cell,
It is housed in a box-shaped first frame formed by suspending a side wall portion around the lower surface plate and the lower surface plate,
Folding the outer periphery of the exterior body to the outer peripheral side of the side wall of the first frame,
A top frame and a box-shaped second frame that is formed by suspending a side wall from the periphery of the top plate are closed to form an outer peripheral surface of the side wall of the first frame and a side wall of the second frame. The outer periphery of the exterior body is stored between the inner peripheral surface,
The folded fold of the outer periphery of the exterior body is an unsealed region, and the unsealed region is sandwiched between an upper portion of a side wall portion of the first frame body and the upper surface plate of the second frame body. Flat type electrochemical cell. 2. The flat electrochemical according to claim 1, wherein a resin portion is provided on at least one of a side wall portion of the first frame body or an inner periphery of the side wall portion of the second frame body that is in contact with a peripheral edge portion of the exterior body. cell. When a plurality of flat electrochemical cells are overlapped, a plurality of convex engaging portions that engage the lower surface plate and the upper surface plate of adjacent flat electrochemical cells are provided on the lower surface plate and the upper surface plate. flat electrochemical cell according to claim 1 or claim 2, characterized in that the set provided. The flat electrochemical cell according to claim 3 , wherein openings are provided in the lower surface plate and the upper surface plate . Provided a safety valve for letting out the gas generated inside the exterior body outside the exterior body periphery,
The safety valve is
A valve part that opens when the gas pressure inside the exterior body exceeds a predetermined value;
An accommodating portion for accommodating the gas and electrolyte that have passed through the valve portion;
A gas permeation part that allows only gas to permeate from the housing part,
The accommodating portion is an unsealed region provided in a part of the outer periphery of the exterior body,
The flat electrochemical cell according to any one of claims 1 to 4, wherein the gas permeable portion is a polymer sheet that closes an exterior body opening formed on the unsealed region . The flat electrochemical cell according to claim 5 , wherein the polymer sheet is a porous fluororesin sheet . The flat electrochemical cell according to claim 6, wherein the porous fluororesin sheet is a stretched porous polytetrafluoroethylene sheet . The flat type according to any one of claims 5 to 7, wherein the valve portion is configured by sandwiching a peripheral edge portion of the exterior body between a side wall portion of the first frame body and the upper surface plate. Electrochemical cell. An assembled battery comprising a combination of a plurality of flat electrochemical cells according to any one of claims 1 to 8.