JP2021170486A - Power storage cell - Google Patents

Abstract

To provide a power storage cell capable of reducing the generation of a short circuit when an abnormality occurs.SOLUTION: A power storage cell 2 is provided with, in a join area K between current collectors 22 and a spacer 14, a fragile part Ka, where a joint strength between the spacer 14 and the current collectors 22 is lower than that in other sites of the join area K, from an edge Kb on an active material layer 21 formation area side to an edge Kc on a current collector 22 outer edge side in the plane direction of the join area K. In the fragile part Ka, one side 22a of each current collector 22 is a roughened surface R, and the spacer 14 comprises: first resin parts 31 each having a higher melting point than the temperature of gas G generated in a cell when an abnormality occurs, each first resin part being joined to the one side 22a of each current collector 22; and second resin parts 32 each having a lower melting point than the gas G, the second resin parts being disposed to be sandwiched between the first resin parts 31.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a power storage cell.

As a conventional storage cell, for example, there is a cell used for a bipolar battery described in Patent Document 1. This conventional bipolar battery is configured to include a laminate of first and second cells. The first cell and the second cell have a positive electrode, a negative electrode, and a separator interposed therein. In the first cell and the second cell, the edge portion of the metal layer on the positive electrode side and the edge portion of the metal layer on the negative electrode side are joined by, for example, a resin encapsulant.

Special Table 2018-591646

In the storage cell as described above, gas may be generated in the cell at the time of abnormality, and the cell may expand due to the gas. When the storage cell expands, the stress due to the expansion tends to be concentrated on the fixed end of the metal layer, that is, the end of the joint portion between the metal layer and the sealing material. In this case, it is conceivable that the metal layer is damaged or the metal layer is largely peeled off from the sealing material in the vicinity of the end of the joint portion between the metal layer and the sealing material, and a short circuit occurs in the storage cell.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a power storage cell capable of reducing the occurrence of a short circuit at the time of abnormality.

The power storage cell according to one aspect of the present disclosure includes a pair of positive and negative current collectors in which an active material layer is provided in a predetermined forming region on one surface and the active material layers are arranged so as to face each other, and an active material layer. A separator arranged in the current collector and a spacer which is joined to the peripheral edge portion outside the formed region on one surface of a pair of positive and negative current collectors and seals the space between the current collectors. In the joint region with the spacer, a fragile portion where the joint strength between the spacer and the current collector is lower than other parts of the joint region is formed from the edge on the formation region side to the outer edge side of the current collector in the plane direction of the joint region. It is provided over the edge, and in the fragile part, one surface of the current collector is a roughened surface, and the spacer has a melting point higher than the temperature of the gas generated in the cell at the time of abnormality, and a pair of positive and negative current collectors. It is composed of a first resin portion bonded to each one surface of the electric body and a second resin portion having a melting point lower than the temperature of the gas and arranged so as to be sandwiched between the first resin portions. Has been done.

In this storage cell, when gas is generated in the cell at the time of abnormality and the internal pressure of the cell rises, the second resin portion having a melting point lower than the temperature of the gas in the fragile portion takes precedence over the first resin portion. It can be melted and the gas can be released to the outside from the melted portion. That is, in this power storage cell, since the fragile portion functions as a pressure adjusting valve at the time of abnormality, it is possible to prevent the cell from expanding at the time of abnormality. Further, in the fragile portion, the first resin portion having a melting point higher than that of the gas is firmly bonded to the current collector by the roughened surface. Therefore, even after the second resin portion is melted, the first resin portion remains, and the bonded state between the first resin portion and the current collector is maintained. Therefore, it is possible to reduce short-circuiting between the current collectors because the first resin portion remains on one surface of the current collectors even after the gas is discharged to the outside.

The roughened surface may be provided over the entire surface of at least one of a pair of positive and negative current collectors. In this case, the formation of the fragile portion can be simplified as compared with the case where the roughened surface is selectively formed only in the region corresponding to the fragile portion.

The current collector has a rectangular shape, and the fragile portion may be provided corresponding to a side portion located between the corner portions of the current collector. In this case, it becomes easy to design the fragile portion to have a certain width, and the fragile portion can be more reliably functioned as a pressure adjusting valve at the time of abnormality.

The peripheral edge of the separator may be held buried in the spacer. In this case, the displacement of the separator in the cell can be suppressed, and the active material layers can be prevented from coming into contact with each other without interposing the separator.

The peripheral edge portion of the separator may be held in a state of being sandwiched between one of a pair of positive and negative current collectors and the first resin portion. In this case, the displacement of the separator in the cell can be suppressed, and the active material layers can be prevented from coming into contact with each other without interposing the separator. Further, since the separator is held by the current collector and the first resin portion, the holding state of the separator is maintained even when the fragile portion functions as a pressure adjusting valve.

According to the present disclosure, the occurrence of a short circuit at the time of abnormality can be reduced.

It is a schematic cross-sectional view which shows the power storage device which comprises one Embodiment of the power storage cell. It is an enlarged sectional view in the vicinity of a spacer in a storage cell. It is a top view which shows the junction area of a current collector and a spacer. It is a top view of the current collector. It is an enlarged cross-sectional view which shows the layer structure of a spacer. It is a top view of the resin film which constitutes a spacer. It is an enlarged sectional view of the main part which shows the power storage cell at the time of abnormality. It is an enlarged sectional view of the main part of the power storage cell which concerns on a modification. It is an enlarged sectional view of the main part which shows the storage cell which concerns on the deformation example at the time of abnormality.

Hereinafter, a preferred embodiment of the power storage cell according to one aspect of the present disclosure will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing a power storage device configured to include one embodiment of a power storage cell. The power storage device 1 shown in FIG. 1 is a device used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 is a secondary battery such as a nickel hydrogen secondary battery or a lithium ion secondary battery. The storage cell 2 may be an electric double layer capacitor or an all-solid-state battery. In the following description, the power storage device 1 which is a lithium ion secondary battery will be illustrated.

As shown in FIG. 1, the power storage device 1 includes a cell stack 3 in which a plurality of power storage cells 2 are stacked along the stacking direction D, and a pair of current collector plates arranged at both ends of the cell stack 3 in the stacking direction D. It is configured to include 4. The current collector plate 4 is formed in a rectangular shape by, for example, a metal such as aluminum, copper, or stainless steel. In FIG. 1, one of the pair of current collector plates 4 (lower current collector plate in FIG. 1) is the positive electrode current collector plate 4A, and the other of the pair of current collector plates 4 (upper current collector plate in FIG. 1). ) Is the negative electrode current collector plate 4B. The positive electrode current collector plate 4A and the negative electrode current collector plate 4B are connected to each other outside the apparatus by a bus bar (not shown).

The storage cell 2 includes a positive electrode 11, a negative electrode 12, a separator 13, and a spacer 14. The positive electrode 11 and the negative electrode 12 are composed of a current collector 22 in which the active material layer 21 is provided in a predetermined forming region on one surface 22a. Specifically, the positive electrode 11 is composed of a positive electrode current collector 22A and a positive electrode active material layer 21A rectangularly provided on one surface 22a of the positive electrode current collector 22A, and the negative electrode 12 is a negative electrode current collector 22B. And the negative electrode active material layer 21B provided in a predetermined forming region of one surface 22a of the negative electrode current collector 22B.

The positive electrode 11 and the negative electrode 12 are arranged so that the positive electrode active material layer 21A and the negative electrode active material layer 21B face each other. That is, the positive electrode current collector 22A and the negative electrode current collector 22B, which are a pair of positive and negative current collectors, are one surface 22a on which the positive electrode active material layer 21A is formed and the one surface 22a on which the negative electrode active material layer 21B is formed. Are arranged so as to face each other. The other surface 22b of the current collector 22 constitutes an end surface of the storage cell 2 on the stacking direction D side.

The storage cells 2 and 2 adjacent to each other in the stacking direction D are electrically connected to each other by abutting the other surface 22b of the positive electrode current collector 22A and the other surface 22b of the negative electrode current collector 22B. Further, in the storage cells 2 and 2 adjacent to each other in the stacking direction D, the other surface 22b of the positive electrode current collector 22A and the other surface 22b of the negative electrode current collector 22B come into contact with each other, so that the positive electrode current collector 22A and the negative electrode current collector 22A and the negative electrode current collector are in contact with each other. A pseudo bipolar electrode is formed in which the body 22B is an integral current collector.

In the present embodiment, the positive electrode current collector 22A and the negative electrode current collector 22B have a rectangular shape having the same shape as each other, and the positive electrode active material layer 21A and the negative electrode active material layer 21B are one size smaller than the outer shape of the current collector 22. It is painted in a rectangular shape. In both the positive electrode 11 and the negative electrode 12, the peripheral edge portion 22c of the current collector 22 is an uncoated region in which the active material layer 21 is not coated. Further, in the present embodiment, the negative electrode active material layer 21B is formed to be one size larger than the positive electrode active material layer 21A, and the entire formed region of the positive electrode active material layer 21A is the negative electrode when viewed from the stacking direction D. It is located within the formation region of the active material layer 21B.

The current collector 22 is made of, for example, a copper foil, an aluminum foil, a titanium foil, or a nickel foil. From the viewpoint of ensuring mechanical strength, it is preferable to use aluminum foil as the current collector 22. When the current collector 22 is an alloy, for example, stainless steel foil (for example, SUS304, SUS316, SUS301, SUS304, etc. specified in JIS G 4305: 2015), plated steel plate (for example, JIS G 3141: 2005, etc.) It may be a cold-rolled steel sheet (SPCC or the like) specified in (1) or a plated stainless steel sheet. The current collector 22 may be an alloy foil of the above metal. When the current collector 22 is an alloy foil or a current collector other than the aluminum foil, the surface thereof may be coated with aluminum. In this embodiment, an aluminum foil is used as the positive electrode current collector 22A, and a copper foil is used as the negative electrode current collector 22B.

The positive electrode active material layer 21A is composed of a positive electrode active material such as a composite oxide, metallic lithium, and sulfur. The composition of the composite oxide includes, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum, and lithium. Examples of the composite oxide include olivine-type lithium iron phosphate (LiFePO ₄ ).

The positive electrode active material layer 21A may contain a binder and a conductive auxiliary agent in addition to the positive electrode active material. The binder serves to anchor the active material or conductive aid to the surface of the current collector and maintain a conductive network in the electrodes. Examples of the binder include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins and poly (). Examples thereof include acrylic resins such as meta) acrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, sodium alginate, alginates such as ammonium alginate, water-soluble cellulose ester crosslinked products, and starch-acrylic acid graft polymers. can. These binders can be used alone or in combination. The conductive auxiliary agent is, for example, acetylene black, carbon black, graphite or the like. As the viscosity adjusting solvent, for example, N-methyl-2-pyrrolidone (NMP) or the like is used.

The negative electrode active material layer 21B includes, for example, graphite, artificial graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, carbon such as soft carbon, metal compounds, elements or compounds that can be alloyed with lithium, boron-added carbon, and the like. It is composed of the negative electrode active material of. Examples of elements that can be alloyed with lithium include silicon and tin. As the conductive auxiliary agent and the binder, the same ones as those described above for the positive electrode active material layer 21A can be used.

The separator 13 is a sheet-like member that separates the positive electrode 11 and the negative electrode 12. The separator 13 has a rectangular shape that is one size larger than the formation region of the positive electrode active material layer 21A and the negative electrode active material layer 21B and one size smaller than the current collector 22. As the separator 13, for example, a porous film made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is used. The separator 13 may be a woven fabric or a non-woven fabric made of polypropylene, methyl cellulose or the like. The separator 13 is located between the positive electrode active material layer 21A and the negative electrode active material layer 21B, and when viewed from the stacking direction D, the separator 13 covers the entire forming region of the positive electrode active material layer 21A and the negative electrode active material layer 21B. They are arranged so that they overlap. In the present embodiment, the peripheral edge portion 13a of the separator 13 is held in a state of being buried in the spacer 14 (see FIG. 2).

The spacer 14 is a member that seals the space S between the current collectors 22 and 22, and is made of a resin material having electrical insulation. As shown in FIG. 2, the spacer 14 sandwiches, for example, a frame-shaped resin film between the peripheral edge portion 22c of one surface 22a of the positive electrode current collector 22A and the peripheral edge portion 22c of one surface 22a of the negative electrode current collector 22B. It is formed by welding the resin film to the peripheral portions 22c and 22c, respectively. As a result, the spacer 14 is formed by the bonding region K formed between the peripheral portion 22c of the one surface 22a of the positive electrode current collector 22A and the peripheral portion 22c of the one surface 22a of the negative electrode current collector 22B. It is joined to the current collector 22. In the present embodiment, the outer edge of the spacer 14 projects outward from the outer edge of the current collector 22 in the in-plane direction of the current collector 22. The overhanging portions of the spacers 14 adjacent to each other in the stacking direction D may be welded to each other by hot plate welding or the like, or may be covered from the outside by another sealing material.

Examples of the material for forming the spacer 14 include a resin member exhibiting electrical insulation and heat resistance. Examples of such a resin member include polyimide, polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and PA66. An electrolytic solution (not shown) is housed in the space S and the separator 13 sealed by the spacer 14. The electrolytic solution is, for example, a carbonate-based or polycarbonate-based electrolytic solution. The supporting salt contained in the electrolytic solution is, for example, a lithium salt. The lithium salt is, for example, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , or a mixture thereof.

Next, the joint region K between the current collector 22 and the spacer 14 described above will be described in more detail.

FIG. 3 is a plan view showing a joint region between the current collector and the spacer. As shown in the figure, a rectangular frame-shaped spacer 14 is arranged on the peripheral edge portion 22c of the current collector 22. The joint region K between the current collector 22 and the spacer 14 is formed in a frame shape at the peripheral portion 22c of the current collector 22 at the overlapping portion with the rectangular frame-shaped spacer 14. The joint region K is provided with a fragile portion Ka in which the joint strength between the spacer 14 and the current collector 22 is lower than that of other portions of the joint region K.

In the example of FIG. 3, the fragile portion Ka is provided at one location in the central portion of one side portion (here, one long side) 22e located between the corner portions 22d and 22d of the rectangular current collector 22. There is. The fragile portion Ka is provided from the edge Kb on the formation region side of the active material layer 21 to the edge Kc on the outer edge side of the current collector 22 in the plane direction of the joint region K, and is a fragile portion in the direction orthogonal to the side portion 22e. The length of Ka is equal to the length of the junction region K in the same direction. The length of the fragile portion Ka in the direction along the side portion 22e is sufficiently smaller than the length of the side portion 22e, but the amount of gas generated at the time of abnormality estimated from the type and capacity of the electrolyte. It is set appropriately based on.

In forming the fragile portion Ka, as shown in FIG. 4, a roughened surface R is formed on one surface 22a of the current collector 22. In the example of FIG. 4, the entire one surface 22a of the current collector 22 is a roughened surface R. The roughened surface R can be realized, for example, by forming a plurality of protrusions by electrolytic plating. By forming a plurality of protrusions on the roughened surface R, at the bonding interface between the current collector 22 and the spacer 14, the molten resin enters between the plurality of protrusions formed by the roughened surface, and an anchor effect is obtained. It will be demonstrated.

The roughened surface R may be formed only on the portion of one surface 22a of the current collector 22 corresponding to the fragile portion Ka, or only on the portion corresponding to the fragile portion Ka and its peripheral portion. In this case, the patterning of the roughened surface R can be realized, for example, by forming a plurality of protrusions by electrolytic plating on the portion where the mask is not arranged while the mask is arranged on the portion where the roughened surface R is not formed. The roughened surface R may be provided on both one surface 22a of the positive electrode current collector 22A and one surface 22a of the negative electrode current collector 22B, or may be provided on only one of them. In the present embodiment, the roughened surface R is provided on both one surface 22a of the positive electrode current collector 22A and one surface 22a of the negative electrode current collector 22B.

Further, in forming the fragile portion Ka, as shown in FIG. 5, the spacer 14 includes the first resin portion 31 formed of a resin material having a melting point higher than the temperature of the gas generated in the cell at the time of abnormality and the first resin portion 31. It is composed of a second resin portion 32 having a melting point lower than the temperature of the gas. Examples of the resin material of the first resin portion 31 include acid-modified polypropylene. Examples of the resin material of the second resin portion 32 include polyethylene. The first resin portion 31 is welded to the peripheral edge portion 22c of the positive electrode current collector 22A and the peripheral edge portion 22c of the negative electrode current collector 22B, respectively. The second resin portion 32 is arranged so as to be sandwiched between the first resin portions 31 and 31, and is welded to the first resin portions 31 and 31, respectively.

In the present embodiment, as shown in FIG. 6, four layers of resin films 35A to 35D are used to form the spacer 14 having the fragile portion Ka. The resin film 35A shown in FIG. 6A is a film constituting the first resin portion 31 bonded to the peripheral edge portion 22c of the one side surface 22a of the negative electrode current collector 22B. The resin film 35A is formed of the constituent material of the first resin portion 31, and has a rectangular frame shape so as to overlap the peripheral edge portion 22c of the negative electrode current collector 22B.

The resin film 35B shown in FIG. 6B and the resin film 35C shown in FIG. 6C are films constituting the second resin portion 32 sandwiched between the first resin portions 31 and 31. The resin film 35B and the resin film 35C have a first portion 35a made of the constituent material of the first resin portion 31 and a second portion 35b made of the constituent material of the second resin portion 32. doing. The first portion 35a has a frame shape excluding the fragile portion Ka, and the second portion 35b has a rectangular shape corresponding to the fragile portion Ka. The resin film 35B and the resin film 35C are formed in the same rectangular frame shape as the resin film 35A by combining the first portion 35a with the second portion 35b.

The resin film 35D shown in FIG. 6D is a film constituting the first resin portion 31 bonded to the peripheral edge portion 22c of the one side surface 22a of the positive electrode current collector 22A. Like the resin film 35A, the resin film 35D is formed of the constituent material of the first resin portion 31, and has a rectangular frame shape so as to overlap the peripheral edge portion 22c of the positive electrode current collector 22A. These four layers of resin films 35A to 35D are arranged between the positive electrode current collector 22A and the negative electrode current collector 22B, and welded to the positive electrode current collector 22A and the negative electrode current collector 22B using a heating means such as a heater. By doing so, the spacer 14 having the structure shown in FIG. 5 can be formed.

Further, in the present embodiment, when the spacer 14 is formed, the peripheral edge portion 13a of the separator 13 is arranged between the resin film 35B and the resin film 35C, and the positive electrode current collector 22A and the negative electrode current collector 22B are formed. Welding of the resin films 35A to 35D is carried out. As a result, the peripheral edge portion 13a of the separator 13 is held in a state of being buried in the second resin portion 32 of the spacer 14 (see FIG. 5).

In the storage cell 2 having the above configuration, when gas is generated in the cell at the time of abnormality and the internal pressure of the cell rises, as shown in FIG. 7, the melting point of the fragile portion Ka is higher than the temperature of the gas G. The lower second resin portion 32 melts in preference to the first resin portion 31. As a result, the space S in the cell communicates with the outside of the cell, and the gas G can be discharged to the outside from the melting portion. That is, in this power storage cell 2, since the fragile portion Ka functions as a pressure adjusting valve at the time of abnormality, it is possible to prevent the cell from expanding at the time of abnormality. By preventing the expansion of the cell, for example, it is possible to prevent stress due to expansion from concentrating on the end portion P of the joint portion between the current collector 22 and the spacer 14, and the current collector 22 can be damaged or greatly peeled from the spacer 14. Can be prevented. Further, in the fragile portion Ka, the first resin portion 31 having a melting point higher than that of the gas G is firmly bonded to the current collector 22 by the roughened surface R. Therefore, even after the second resin portion 32 is melted, the first resin portion 31 remains, so that the bonded state between the first resin portion 31 and the current collector 22 is maintained. Since the first resin portion 31 remains on one surface 22a of the current collector 22 even after the gas G is discharged to the outside, it is possible to reduce the short circuit between the current collectors 22 and 22.

In the present embodiment, the roughened surface R is provided over the entire one surface 22a of the current collector 22. As a result, the formation of the fragile portion Ka can be simplified as compared with the case where the roughened surface R is selectively formed only in the region corresponding to the fragile portion Ka.

Further, in the present embodiment, the current collector 22 has a rectangular shape, and the fragile portion Ka is provided corresponding to the side portion 22e located between the corner portions 22d and 22d of the current collector 22. In this case, it becomes easy to design the fragile portion to have a certain width, and the fragile portion can be more reliably functioned as a pressure adjusting valve at the time of abnormality.

Further, in the present embodiment, the peripheral edge portion 13a of the separator 13 is held in a state of being buried in the spacer 14. In this case, the displacement of the separator 13 in the cell can be suppressed, and the positive electrode active material layer 21A and the negative electrode active material layer 21B can be prevented from coming into contact with each other without interposing the separator 13.

When the storage cells 2 are stacked to form the cell stack 3, the position of the fragile portion Ka of each storage cell 2 is viewed from the stacking direction D on the side surface extending along the stacking direction D of the cell stack 3. It is preferable that they match. In this case, since the positions where the gas G is discharged at the time of abnormality are aligned, it becomes easy to arrange a member (for example, a cooling member) that receives the released gas G.

The present disclosure is not limited to the above embodiment. For example, in the above embodiment, the roughened surface R is formed by a plurality of protrusions by electrolytic plating, but the formation of the roughened surface R is not limited to electrolytic plating, and other methods such as etching may be used. Further, for example, in the above embodiment, the peripheral edge portion 13a of the separator 13 is buried in the spacer 14, but the separator 13 does not necessarily have to be held by the spacer 14. Further, as shown in FIG. 8, the peripheral edge portion 13a of the separator 13 may be held in a state of being sandwiched between one of the positive electrode current collector 22A and the negative electrode current collector 22B and the first resin portion 31.

In the example of FIG. 8, the peripheral edge portion 13a of the separator 13 is sandwiched between the negative electrode current collector 22B and the first resin portion 31. Even in such a configuration, the displacement of the separator 13 in the cell can be suppressed, and the positive electrode active material layer 21A and the negative electrode active material layer 21B can be prevented from coming into contact with each other without interposing the separator 13. Further, as shown in FIG. 9, since the first resin portion 31 remains on the peripheral edge portion 22c of the negative electrode current collector 22B even after the second resin portion 32 is melted at the time of abnormality, the fragile portion Ka is a pressure adjusting valve. The holding state of the separator 13 is maintained even when the separator 13 functions as a function.

When the peripheral edge portion 13a of the separator 13 is sandwiched between one of the positive electrode current collector 22A and the negative electrode current collector 22B and the first resin portion 31, the separator 13 is sandwiched between any of the current collectors 22 and the first resin portion 31. Whether to sandwich the peripheral edge portion 13a is selected in consideration of the material of the current collector 22 and the like. For example, when the current collector 22 is electrolytically plated to provide a roughened surface R as in the present embodiment, the current collector 22 and the first resin portion 31 on which a plurality of protrusions due to the electrolytic plating are likely to grow The peripheral edge portion 13a of the separator 13 may be sandwiched between them. When the positive electrode current collector 22A is an aluminum foil and the negative electrode current collector 22B is a copper foil as in the present embodiment, the peripheral edge portion 13a of the separator 13 is located between the negative electrode current collector 22B and the first resin portion 31. It is preferable to sandwich.
Further, in the above embodiment, the fragile portion Ka is provided at the central portion of one side portion located between the corner portions 22d and 22d of the rectangular current collector 22, but the fragile portion Ka is provided at the corner portion 22d, It is preferable that 22d is not included, and it is not always necessary to include the central portion in the side portion. The peripheral edge portion 22c of the current collector 22 may be buried in the spacer 14.

2 ... Storage cell, 13 ... Separator, 13a ... Peripheral part, 14 ... Spacer, 21 ... Active material layer, 22 ... Current collector, 22a ... One side, 22c ... Peripheral part, 22d ... Corner part, 22e ... Side part, 31 ... 1st resin part, 32 ... 2nd resin part, K ... bonding region, Ka ... fragile part, Kb ... edge on the formation region side, Kc ... outer edge side edge, R ... roughened surface, S ... space ..

Claims (5)

A pair of positive and negative current collectors in which the active material layer is provided in a predetermined forming region on one surface and the active material layers are arranged so as to face each other.
The separator arranged between the active material layers and
The pair of positive and negative current collectors are provided with spacers that are joined to the outer peripheral edges of the formed region on one surface of the current collector and seal the space between the current collectors.
In the joint region between the current collector and the spacer, a fragile portion having a lower joint strength between the spacer and the current collector than other parts of the joint region is formed in the plane direction of the joint region. It is provided from the side edge to the outer edge side edge of the current collector.
In the fragile portion, one surface of the current collector is a roughened surface, the spacer has a melting point higher than the temperature of the gas generated in the cell at the time of abnormality, and the pair of positive and negative current collectors. By a first resin portion bonded to each of the one surfaces thereof and a second resin portion having a melting point lower than the temperature of the gas and arranged so as to be sandwiched between the first resin portions. The storage cell that is configured. The storage cell according to claim 1, wherein the roughened surface is provided over the entire surface of at least one of the positive and negative current collectors. The current collector has a rectangular shape and has a rectangular shape.
The storage cell according to claim 1, wherein the fragile portion is provided corresponding to a side portion located between the corner portions of the current collector. The power storage cell according to any one of claims 1 to 3, wherein the peripheral edge portion of the separator is held in a state of being buried in the spacer. The storage cell according to any one of claims 1 to 3, wherein the peripheral edge portion of the separator is held in a state of being sandwiched between one of the pair of positive and negative current collectors and the first resin portion.

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