JP2018139188A - Power storage element and power storage device including the power storage element - Google Patents

Abstract

An electric storage device capable of pressing an electrode body in a wide range of a case, and an electric storage device including the electric storage device. An electrode body having a stacked positive electrode and a negative electrode, and a case accommodating the electrode body are provided, and the case is arranged in a stacking direction of the positive electrode and the negative electrode, and faces the outer surface of the electrode body. A wall portion and a connection wall portion that connects opposing ends of the opposing wall portion to each other, wherein the connection wall portion has a ridge line extending in a direction intersecting a direction in which the pair of wall portions are arranged, and It has a bending part which can be bent and deformed along it. [Selection diagram] Fig. 3

Description

  The present invention relates to a power storage element including a case and an electrode body accommodated in the case, and a power storage device including the power storage element.

  Conventionally, a flat secondary battery in which an electrode body is housed in an outer can is known (see Patent Document 1). As shown in FIG. 16, the flat secondary battery has a flat spiral electrode body 502 wound in a state in which a positive electrode and a negative electrode are stacked via a separator, and the electrode body 502 is inserted. A flat outer can 503 into which an electrolytic solution is injected, and a sealing plate 504 that hermetically seals the outer can 503 are provided.

  In the flat secondary battery 501, the outer can 503 has a cylindrical shape with the bottom closed and the opposing both surfaces having a flat wide flat surface, and is open upward. Further, the sealing plate 504 is welded to the opening of the outer can 503 so as to hermetically seal the opening of the outer can.

  The flat secondary battery 501 described above is used for the battery pack 500. The battery pack 500 includes a battery stack 505 configured by being stacked with an insulating material interposed therebetween, end plates 506 disposed on both end surfaces of the battery stack 505, and a bind bar that connects the end plates 506. .

  The end plate 506 is connected to the bind bar to pressurize the battery stack 505 from both end surfaces, and compress and fix each flat secondary battery 501 in a state of pressing in the stacking direction. Thereby, each flat secondary battery 501 of the battery stack 505 is fixed in a pressurized state with a predetermined compression pressure. Further, the insulating material compresses the swollen electrode body 502 by uniformly compressing the entire surface of the facing wide plane of the outer can 503 or pressing the center of the wide plane more strongly than the outer peripheral portion.

  At this time, the bottom of the outer can 503 of the flat secondary battery 501 is flat and extends in a direction perpendicular to the standing direction of the wall (wide plane). As a result, it is difficult for the compressive force to act on the electrode body 502 on the bottom side of the wide plane of the outer can 503.

WO2014 / 024424

  Therefore, an object of the present embodiment is to provide a power storage element capable of pressing an electrode body in a wide range of cases, and a power storage device including the power storage element.

The electricity storage device of this embodiment is
An electrode body having stacked electrodes;
A case in which the electrode body is accommodated,
The case includes a pair of opposing wall portions facing the outer surface of the electrode body side by side in the stacking direction of the electrodes, and a connection wall portion connecting the opposing end portions of the opposing wall portion,
The connection wall portion has a ridge line extending in a direction intersecting with a direction in which the pair of opposed wall portions are arranged, and a bending portion that can be bent and deformed along the ridge line.

  According to this configuration, the connection wall portion has the bending portion that can be bent and deformed along the ridge line extending in the direction intersecting the direction in which the pair of wall portions are arranged. When a force is applied in the line-up direction, the bending portion is easily bent and deformed along the ridge line by the force, and the distance between the ends of the pair of opposing wall portions on the connection wall portion side is likely to be reduced. As a result, the electrode body is pressed over a wide range of the case.

In the storage element,
The connection wall portion includes a pair of inclined portions including a proximal end and a distal end opposite to the proximal end and extending in a direction intersecting the opposing wall portion,
The bent portion may include an end bent portion that connects a base end of the inclined portion and the opposing wall portion.

  According to such a configuration, the end bending portion that can be bent and deformed along a ridge line extending in a direction intersecting the direction in which the pair of wall portions are arranged is provided at a position connecting the inclined portion and the opposing wall portion. When a force is applied to the storage element in the direction in which the pair of wall portions are arranged, the end bending portion easily bends and deforms along its own ridge line due to the force, whereby the connection wall portion side of the pair of opposing wall portions The interval is likely to be small at the end of the. As a result, the electrode body is easily pressed over a wide range of the case.

Further, in the power storage element,
The connection wall portion is disposed between tips of the pair of inclined portions, and has a flat plate portion that extends in a direction orthogonal or substantially orthogonal to the opposing wall portion,
The bending portion may include a pair of intermediate bending portions that connect a peripheral edge of the flat plate portion and a tip of the inclined portion.

  According to this configuration, since the flat plate portion that extends in the direction orthogonal to or substantially orthogonal to the opposing wall portion is disposed between the tips of the pair of inclined portions via the intermediate bent portion, the opposing wall is disposed on the pair of opposing wall portions. When a force is applied in the direction in which the portions are arranged, the flat plate portion extends (spreads) in the direction in which the force is applied, so that the force is applied to other parts (intermediate bending portion and end bending portion) of the connection wall portion. It concentrates, and this makes it easy to bend and deform the intermediate bending portion and the end bending portion. For this reason, the distance between the pair of opposing wall portions on the side of the connection wall portion is likely to be smaller, and as a result, the electrode body is further easily pressed over a wide range of the case.

  Moreover, when a force is applied in the direction in which the pair of opposing wall portions are arranged, the flat plate portion extends (expands) in the direction in which the force is applied, so that deformation in the flat plate portion can be suppressed. Excessive deformation in the connecting wall is suppressed.

In the storage element,
The electrode is wound in a stacked state,
The electrode body may be accommodated in the case in a state in which one end portion in the winding central axis direction faces the connection wall portion.

  According to this configuration, since the electrode body is housed in the case with the end in the winding central axis direction disposed near the connection wall portion, the electrode body is arranged in a direction in which the pair of opposing wall portions are aligned with the power storage element. When a force is applied, a force in the direction in which the pair of opposing wall portions are arranged is easily applied to one end portion in the winding central axis direction.

Further, in the power storage element,
The electrode has a metal foil and an active material layer laminated on the metal foil,
The active material layer may be disposed up to the one end of the electrode body in the winding central axis direction.

  According to such a configuration, when a force is applied to the storage element in the direction in which the pair of opposing wall portions are arranged, the force is also easily applied to one end portion of the electrode body, whereby the pair of opposing wall portions are aligned. In the direction, it is possible to suppress the interval between the electrodes wound in the one end portion (specifically, the interval between the active material layers of the electrodes adjacent to each other in the stacking direction) from increasing. As a result, it is possible to prevent performance degradation caused by the increase in the interval.

In addition, the power storage device of the present embodiment is
A plurality of power storage elements of any of the above,
A holding member for holding the plurality of power storage elements,
The plurality of power storage elements are stacked in the direction in which the pair of opposing wall portions are arranged in a state where adjacent power storage elements face each other.
The holding member presses the plurality of power storage elements from the outside in the direction in which the pair of opposing wall portions are arranged.

  In each storage element, when a force is applied in the direction in which the pair of wall portions are arranged, the distance between the pair of opposing wall portions on the connection wall portion side tends to be small. By pressing each power storage element from the outside in the direction in which the pair of opposing wall portions are arranged, the electrode body is pressed in a wide range of the case (opposing wall portion) of each power storage element. Thereby, the performance fall resulting from expansion | swelling of an electrode body is suppressed.

  As described above, according to the present embodiment, it is possible to provide a power storage element that can press the electrode body in a wide range of cases, and a power storage device including the power storage element.

FIG. 1 is a perspective view of a power storage device according to this embodiment. FIG. 2 is an exploded perspective view of the power storage element. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a schematic diagram for explaining an electrode body of the electricity storage element. FIG. 5 is a cross-sectional view of the case body of the electricity storage device. FIG. 6 is a view of the case main body as viewed from the closing portion side. FIG. 7 is an enlarged cross-sectional view of the closed portion of the case body and its periphery. FIG. 8 is a perspective view of a power storage device including the power storage element. FIG. 9 is an exploded perspective view of the power storage device. FIG. 10 is a cross-sectional view of a case body according to another embodiment. FIG. 11 is a cross-sectional view of a case body according to another embodiment. FIG. 12 is a cross-sectional view of a case body according to another embodiment. FIG. 13 is a diagram for explaining a configuration of an electrode body according to another embodiment. FIG. 14 is a diagram for explaining a configuration of an electrode body according to another embodiment. FIG. 15 is a diagram for explaining a configuration of an electrode body according to another embodiment. FIG. 16 is a schematic view of a cross section of a conventional battery pack.

  An embodiment of a power storage device according to the present invention will be described with reference to FIGS. Examples of the power storage element include a primary battery, a secondary battery, and a capacitor. In the present embodiment, a chargeable / dischargeable secondary battery will be described as an example of a power storage element. In addition, the name of each component (each component) of this embodiment is a thing in this embodiment, and may differ from the name of each component (each component) in background art.

  The electricity storage device of this embodiment is a nonaqueous electrolyte secondary battery. More specifically, the power storage element is a lithium ion secondary battery that utilizes electron transfer that occurs as lithium ions move. This type of power storage element supplies electrical energy. One or a plurality of power storage elements are used. Specifically, the storage element is used singly when the required output and the required voltage are small. On the other hand, when at least one of a required output and a required voltage is large, the power storage element is used in a power storage device in combination with another power storage element. In the power storage device, a power storage element used in the power storage device supplies electric energy.

  As shown in FIGS. 1 to 4, the power storage element includes an electrode body 2 having stacked electrodes (a positive electrode 23 and a negative electrode 24), and a case 3 in which the electrode body 2 is accommodated. In addition, the power storage element 1 includes an external terminal 4 disposed outside the case 3, a current collector 5 that connects the electrode body 2 and the external terminal 4, and between the electrode body 2 and the current collector 5 and the case 3. And an insulating member 6 disposed on the surface.

  The electrode body 2 has wound electrodes (a positive electrode 23 and a negative electrode 24). The electrode body 2 has a flat cylindrical shape, and the curved portions 201 and 202 in which the electrodes 23 and 24 are laminated in a curved state and the flat in which the electrodes 23 and 24 are laminated in a flat or substantially flat state. Part 203 (see FIG. 4). Details are as follows.

  The electrode body 2 has electrodes (positive electrode 23 and negative electrode 24) wound in a stacked state. Specifically, the electrode body 2 includes a winding core 21, and a stacked body 22 in which the positive electrode 23 and the negative electrode 24 are stacked in a state of being insulated from each other and wound around the winding core 21 (FIG. 3). reference). As the lithium ions move between the positive electrode 23 and the negative electrode 24 in the electrode body 2, the power storage device 1 is charged and discharged.

  The winding core 21 is usually formed of an insulating material. The core 21 of this embodiment is a flat cylinder shape. The winding core 21 is formed by winding a sheet having flexibility or thermoplasticity.

  The positive electrode 23 includes a strip-shaped metal foil 231 and a positive electrode active material layer 232 stacked on the metal foil 231.

  In this metal foil 231, a part 201 </ b> A corresponding to the curved part 201 protrudes to one side in the width direction from a part 203 </ b> A corresponding to the flat part 203 at one edge in the width direction (upper edge in FIG. 4). . Specifically, the other edge in the width direction of the metal foil 231 (the lower edge in FIG. 4) is straight in the longitudinal direction of the metal foil 231, and one edge in the width direction is the curved portion 201. The portion 201A corresponding to the projection protrudes in the width direction from the portion 203A corresponding to the flat portion 203. The portions 201A corresponding to the curved portions 201 and the portions 203A corresponding to the flat portions 203 are alternately arranged in the longitudinal direction. In the electrode body 2 around which the positive electrode 23 configured as described above is wound, the curved portion 201 protrudes from the flat portion 203 at one end portion (upper portion in FIG. 4) in the winding center axis C direction. The metal foil 231 of this embodiment is, for example, an aluminum foil.

  In addition, the positive electrode active material layer 232 protrudes to one side in the width direction from a portion 203A corresponding to the flat portion 203 in the metal foil 231 (a portion including the portion 201A corresponding to the curved portion 201: an uncovered portion). Is overlaid on the metal foil 231 in a state where is exposed.

  The negative electrode 24 includes a strip-shaped metal foil 241 and a negative electrode active material layer 242 stacked on the metal foil 241.

  In this metal foil 241, at one end edge in the width direction (upper end edge in FIG. 4), a portion 202B corresponding to the curved portion 202 protrudes to one side in the width direction from a portion 203B corresponding to the flat portion 203. . Specifically, the other edge in the width direction of the metal foil 241 (the lower edge in FIG. 4) is straight in the longitudinal direction of the metal foil 241, and one edge in the width direction is the curved portion 202. And a portion 202B corresponding to the portion protrudes in the width direction from a portion 203B corresponding to the flat portion 203. The portions 202B corresponding to the curved portions 202 and the portions 203B corresponding to the flat portions 203 are alternately arranged in the longitudinal direction. In the electrode body 2 around which the negative electrode 24 configured as described above is wound, the curved portion 202 protrudes from the flat portion 203 at one end portion (upper portion in FIG. 4) in the winding center axis C direction. The metal foil 241 of this embodiment is, for example, a copper foil.

  Further, the negative electrode active material layer 242 protrudes to one side in the width direction from the portion 203B corresponding to the flat portion 203 in the metal foil 241 (the portion including the portion 202B corresponding to the curved portion 202: uncovered portion). Is overlaid on the metal foil 241 in a state of being exposed.

  In the electrode body 2 of the present embodiment, the positive electrode 23 and the negative electrode 24 configured as described above are wound in a state where they are insulated by the separator 25. That is, in the electrode body 2 of this embodiment, the laminated body 22 of the positive electrode 23, the negative electrode 24, and the separator 25 is wound.

  The separator 25 is an insulating member and is disposed between the positive electrode 23 and the negative electrode 24. Thereby, in the electrode body 2 (specifically, the laminated body 22), the positive electrode 23 and the negative electrode 24 are insulated from each other. The separator 25 holds the electrolytic solution in the case 3. Thereby, at the time of charging / discharging of the electrical storage element 1, a lithium ion can move between the positive electrode 23 and the negative electrode 24 which are alternately laminated on both sides of the separator 25. This separator 25 is comprised by porous membranes, such as polyethylene, a polypropylene, a cellulose, polyamide, for example.

  The dimension of the separator 25 in the width direction is slightly larger than the portion of the positive electrode 23 (or the negative electrode 24) excluding the uncovered portion. The separator 25 is arranged between the positive electrode 23 and the negative electrode 24 alternately stacked with the other edge in the width direction aligned in the Z-axis direction. Specifically, the positive electrode active material layer 232 in the positive electrode 23 is disposed. It arrange | positions between the site | part and the site | part in which the negative electrode active material layer 242 in the negative electrode 24 was arrange | positioned (refer FIG. 4). At this time, the uncoated portion of the positive electrode 23 and the uncoated portion of the negative electrode 24 do not overlap. That is, the non-covered portion of the positive electrode 23 overlaps at the position of the curved portion 201 to constitute the uncoated laminated portion 26A, and the non-covered portion of the negative electrode 24 overlaps at the position of the curved portion 202 to constitute the uncoated laminated portion 26B. doing.

  Case 3 includes a pair of long wall portions (opposing wall portions) 313 facing the outer surface of electrode body 2 side by side in the stacking direction (Y-axis direction in FIG. 3) of electrodes 23 and 24 in flat portion 203 of electrode body 2; And a closed portion (connection wall portion) 311 that connects opposite end portions of the long wall portion 313. Details are as follows.

  The case 3 includes a case main body 31 having an opening and a cover plate 32 that closes (closes) the opening of the case main body 31. The case 3 houses the electrolytic solution in the internal space together with the electrode body 2 and the current collector 5. Case 3 is formed of a metal having resistance to the electrolytic solution. The case 3 of the present embodiment is formed of an aluminum metal material such as aluminum or an aluminum alloy, for example.

Here, the electrolytic solution is a non-aqueous electrolytic solution. The electrolytic solution is obtained by dissolving an electrolyte salt in an organic solvent. Examples of the organic solvent include cyclic carbonates such as propylene carbonate and ethylene carbonate, and chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. The electrolyte salt is, for example, LiClO ₄ , LiBF ₄ , and LiPF ₆ .

  Returning to the description of the case 3, the case 3 is formed by joining the opening peripheral edge 34 of the case main body 31 (see FIG. 2) and the peripheral edge of the cover plate 32 in an overlapping state. In the case 3, an internal space is defined by the case main body 31 and the cover plate 32.

  As shown in FIGS. 5 to 7, the case main body 31 includes a plate-shaped closing portion 311 having at least one ridge line, and a cylindrical body portion 312 connected to the periphery of the closing portion 311.

  The body portion 312 has a flat rectangular tube shape. The body portion 312 includes a pair of long wall portions 313 that are parallel to each other, and a pair of short wall portions 314 that connect opposite edges of the pair of long wall portions 313 and are parallel to each other.

  The blocking portion 311 has a ridge line (in the example of this embodiment, a first edge ridge line 3114A) extending in a direction intersecting with the direction in which the pair of wall portions (in the example of this embodiment, the long wall portion 313 or the short wall portion 314) are arranged. , A first intermediate ridge line 3115A, a second end ridge line 3116A, and a second intermediate ridge line 3117A) and a bending portion that can be bent and deformed along the ridge line. The blocking portion 311 of the present embodiment includes a first end bending portion 3114 that can be bent and deformed along the first end ridge line 3114A, a first intermediate bending portion 3115 that can be bent and deformed along the first intermediate ridge line 3115A, A second end bent portion 3116 that can be bent and deformed along the two end ridge lines 3116A and a second intermediate bent portion 3117 that can be bent and deformed along the second intermediate ridge line 3117A are provided. That is, in the closed portion 311 of the present embodiment, the bent portions (bend portions that can be bent and deformed along the ridgeline) are the first end bent portion 3114, the first intermediate bent portion 3115, and the second end bent portion 3116. , And a second intermediate bend 3117.

  In addition, the blocking portion 311 includes a flat plate portion 3110 positioned on the inner side (opening peripheral edge 34 side) of the case 3 than the end edges (end edges opposite to the opening peripheral edge portion 34) of the long wall portion 313 and the short wall portion 314. The first inclined portion 3111 connecting the long wall portion 313 and the flat plate portion 3110, and the second inclined portion 3112 connecting the short wall portion 314 and the flat plate portion 3110. The flat plate portion 3110 and the first inclined portion 3111 are connected via a first intermediate bending portion (intermediate bending portion) 3115, and the flat plate portion 3110 and the second inclined portion 3112 are connected to a second intermediate bending portion (intermediate bending portion). Part) 3117. The first inclined portion 3111 and the long wall portion 313 are connected via a first end bent portion (end bent portion) 3114, and the second inclined portion 3112 and the short wall portion 314 are connected to the second end portion. It is connected via a bent portion (end bent portion) 3116.

  The details of the above-described blocking portion 311 are as follows.

  The flat plate portion 3110 is a portion of a rectangular flat plate that extends in a direction orthogonal to the long wall portion 313 and the short wall portion 314. The outline of the flat plate portion 3110 has a rectangular shape corresponding to the opening peripheral edge portion 34. The flat plate portion 3110 is disposed in the center of a region that is smaller than the opening peripheral edge portion 34 and surrounded by the body portion 312 when viewed from the opening direction of the case body 31 (the normal direction of the flat plate portion 3110). In this embodiment, the long side direction of the flat plate portion 3110 is the X-axis direction, the short side direction of the flat plate portion 3110 is the Y-axis direction, and the normal line (thickness) direction of the flat plate portion 3110 is the Z-axis direction. .

  The first inclined portion 3111 includes a base end that is an end portion on the long wall portion 313 side and a tip end that is an end portion on the opposite side (the flat plate portion 3110 side) of the base end, and intersects the long wall portion 313. Extend in the direction. The first inclined portion 3111 is inclined with respect to the long wall portion 313 and the flat plate portion 3110 (see FIGS. 3 and 7). The base end of the first inclined portion 3111 is connected (connected) to the long wall portion 313 via the first end bent portion 3114, and the distal end of the first inclined portion 3111 is a flat plate via the first intermediate bent portion 3115. It is connected (connected) to the periphery (long side) of the portion 3110. That is, the closing part 311 of this embodiment has a first end bent part 3114 and a first intermediate bent part 3115. Further, the case 3 of the present embodiment has a pair of first inclined portions 3111.

  The first end bent portion 3114 has a first end ridge line 3114A extending in a direction intersecting with the direction in which the pair of long wall portions 313 are arranged (Y-axis direction), and is bent and deformed along the first end ridge line 3114A. Is possible. The first end ridgeline 3114A of the present embodiment extends in the X-axis direction.

  The first intermediate bending portion 3115 has a first intermediate ridge line 3115A extending in a direction intersecting with the direction in which the pair of long wall portions 313 are arranged (Y-axis direction), and can be bent and deformed along the first intermediate ridge line 3115A. . The first intermediate ridge line 3115A of the present embodiment extends in the same direction (X-axis direction) as the first end ridge line 3114A.

  The second inclined portion 3112 includes a proximal end that is an end portion on the short wall portion 314 side and a distal end that is an end portion on the opposite side (the flat plate portion 3110 side) to the short end portion, and with respect to the short wall portion 314. Extend in the intersecting direction. The second inclined portion 3112 is inclined with respect to the short wall portion 314 and the flat plate portion 3110. The proximal end of the second inclined portion 3112 is connected (connected) to the short wall portion 314 via the second end bent portion 3116, and the distal end of the second inclined portion 3112 is connected via the second intermediate bent portion 3117. It is connected (connected) to the peripheral edge (short side) of the flat plate portion 3110. That is, the blocking portion 311 of this embodiment has both the second end bent portion 3116 and the second intermediate bent portion 3117. Further, the case 3 of the present embodiment has a pair of second inclined portions 3112.

  The second end bent portion 3116 has a second end ridge line 3116A extending in a direction intersecting with the direction in which the pair of short wall portions 314 are arranged (X-axis direction), and is bent along the second end ridge line 3116A. It can be deformed. The second end ridge line 3116A of the present embodiment extends in the Y-axis direction.

  The second intermediate bending portion 3117 has a second intermediate ridge line 3117A extending in a direction intersecting with the direction in which the pair of short wall portions 314 are arranged (X-axis direction), and can be bent and deformed along the second intermediate ridge line 3117A. is there. The second intermediate ridge line 3117A of the present embodiment extends in the same direction (Y-axis direction) as the second end ridge line 3116A.

  As described above, the case body 31 has a rectangular tube shape (that is, a bottomed rectangular tube shape) in which one end portion in the opening direction (Z-axis direction) is closed. The case body 31 accommodates the electrode body 2 in a state where the winding central axis C direction (see FIG. 3) is aligned with the Z-axis direction. Specifically, the electrode body 2 is accommodated in the case body 31 with the flat portion 203 facing the long wall portion 313 and the tops of the curved portions 201 and 202 facing the short wall portion 314. The electrode body 2 is in a state in which the other end portion in the direction of the winding center axis C (the end portion on the side opposite to the end portion where the non-coated laminated portions 26A and 26B are disposed) is opposed to the closing portion 311. And accommodated in the case body 31 (see FIG. 3). At this time, the other end of the electrode body 2 is in a position close to the flat plate portion 3110 of the closing portion 311 (for example, a position in contact with the flat plate portion 3110 via the insulating member 6).

  The lid plate 32 is a plate-like member that closes the opening of the case body 31. Specifically, the contour shape of the cover plate 32 corresponds to the opening peripheral edge 34 of the case body 31 when viewed from the Z-axis direction. That is, the lid plate 32 is a rectangular plate-like member that is long in the X-axis direction when viewed from the Z-axis direction.

  The lid plate 32 of the present embodiment is provided with a liquid injection hole 325 for injecting an electrolytic solution (see FIG. 2). The liquid injection hole 325 penetrates the lid plate 32 in the Z-axis direction (thickness direction). The liquid injection hole 325 is sealed (sealed) with a liquid injection stopper 326. That is, the case 3 has a liquid injection stopper 326 that seals the liquid injection hole 325 of the lid plate 32. The liquid filling tap 326 of this embodiment is fixed to the lid plate 32 by welding.

  The external terminal 4 is a part that is electrically connected to an external terminal of another power storage element or an external device. The external terminal 4 is formed of a conductive member. For example, the external terminal 4 is formed of a highly weldable metal material such as an aluminum-based metal material such as aluminum or an aluminum alloy, or a copper-based metal material such as copper or a copper alloy. The external terminal 4 of this embodiment has a surface 41 to which a bus bar or the like can be welded.

  The current collector 5 is formed of a conductive member, and allows the electrode body 2 and the external terminal 4 to be energized. Specifically, the current collector 5 includes a first connection portion 51 connected to the external terminal 4 and a second connection portion 52 connected to the electrode body 2.

  The first connection portion 51 is a plate-like portion extending from the external terminal 4 along the lid plate 32 toward the short wall portion 314. The second connection portion 52 is a plate-like portion that extends from the end portion on the short wall portion 314 side of the first connection portion 51 and extends in a curved state along the non-covered laminated portions 26A and 26B. The second connection portion 52 is connected to the non-covered laminated portions 26A and 26B by welding, for example.

  The current collector 5 configured as described above is disposed on each of the positive electrode and the negative electrode of the electricity storage device 1 (see FIG. 2). In the power storage device 1 of the present embodiment, the case 3 is disposed at positions corresponding to the positive electrode uncoated laminated portion 26A and the negative electrode uncoated laminated portion 26B of the electrode body 2, respectively. The positive electrode current collector 5 and the negative electrode current collector 5 are formed of different materials. Specifically, the positive electrode current collector 5 is formed of, for example, aluminum or an aluminum alloy, and the negative electrode current collector 5 is formed of, for example, copper or a copper alloy.

  The insulating member 6 is disposed between the case 3 (specifically, the case main body 31), the electrode body 2 and the current collector 5. The insulating member 6 is made of an insulating resin. The insulating member 6 of this embodiment is a bag shape formed by bending an insulating sheet-like member cut into a predetermined shape.

  The power storage device 1 includes the first intermediate bending portion 3115 that can be bent and deformed along the first intermediate ridge line 3115A in which the closing portion 311 extends in the direction intersecting the Y-axis direction. For this reason, when a force is applied to the storage element 1 (case 3) in the Y-axis direction, the first intermediate bending portion 3115 is easily bent and deformed along its own ridge line (first intermediate ridge line) 3115A. Thereby, in case 3, compared with the case where obstruction part 311 is flat plate shape (namely, flat plate without a ridgeline) perpendicular to a long wall part and a short wall part, it is on the obstruction part 311 side of a pair of long wall parts 313. The distance between the end portions tends to be small. As a result, the electrode body 2 is pressed over a wide range of the case 3.

  Moreover, in the electrical storage element 1 of the present embodiment, the blocking portion 311 connects the base end of the first inclined portion 3111 and the long wall portion 313 and intersects the Y-axis direction (X-axis direction in the present embodiment). The first end ridge line 3114A has a first end ridge line 3114A that extends and can be bent and deformed along the first end ridge line 3114A. Thereby, when a force is applied to the electricity storage element 1 in the Y-axis direction, the first end bending portion 3114 in addition to the first intermediate bending portion 3115 is also along the ridge line (first end ridge line) 3114A by the force. It is easy to bend and deform. For this reason, the distance between the pair of long wall portions 313 on the closing portion 311 side is likely to be smaller, and as a result, the electrode body 2 is more easily pressed over a wide range of the case 3.

  In the power storage device 1 of the present embodiment, in the case 3, each of the pair of first intermediate bending portions 3115 connects the peripheral edge of the flat plate portion 3110 and the tip of the first inclined portion 3111. In this energy storage device 1, when a force is applied to the pair of long wall portions 313 from the outside in the Y-axis direction, the flat plate portion 3110 extends (expands) in the direction in which the force is applied. The force concentrates on the first part (first intermediate bent part 3115, first end bent part 3114, etc.). Thereby, the 1st intermediate | middle bending part 3115 and the 1st end part bending part 3114 become easier to bend and deform. For this reason, the distance between the pair of long wall portions 313 on the closing portion 311 side is likely to be smaller, and as a result, the electrode body 2 is more easily pressed in a wide range of the case 3. In addition, when a force is applied in the Y-axis direction, the flat plate portion 3110 extends (expands) in the direction in which the force is applied, so that deformation in the flat plate portion 3110 is suppressed, so that the closed portion of the case 3 Excessive deformation at 311 is suppressed.

  Further, in the power storage device 1 of the present embodiment, the electrode body 2 is accommodated in the case 3 with one end portion in the winding central axis C direction facing the closing portion 311. In this way, the other end of the electrode body 2 in the winding center axis C direction (the end opposite to the end where the non-coated laminated portions 26A and 26B are disposed) is brought close to the closing portion 311. By being accommodated in the case 3 in a state, when a force is applied to the power storage element 1 in the Y-axis direction, the force in the Y-axis direction is also applied to the other end portion in the winding center axis C direction. It becomes easy to join.

  In the electrode body 2 of the present embodiment, the active material layers 232 and 242 are arranged up to the other end of the electrode body 2 in the winding center axis C direction. In the electricity storage device 1 of the present embodiment, the force is also easily applied to the other end of the electrode body 2 when a force is applied to the electricity storage device 1 from the outside in the Y-axis direction. For this reason, when a force is applied to the storage element 1 from the outside in the Y-axis direction, the distance between the wound electrodes 23 and 24 at the other end of the electrode body 2 (specifically, the stacking direction) The distance between the active material layers 232 and 242 of the electrodes 23 and 24 adjacent to each other is suppressed. As a result, in the electricity storage device 1, it is possible to prevent the performance degradation due to the increase in the interval.

  Next, an embodiment of a power storage device according to the present invention will be described with reference to FIGS. In the following description, the same reference numerals are used for the same components as in the above embodiment.

  The power storage device of the present embodiment includes the power storage element 1 of the above embodiment. Specifically, the power storage device 10 includes a plurality of power storage elements 1 and a holding member 11 that holds the plurality of power storage elements 1. The power storage device 10 electrically connects the adjacent member 12 adjacent to the power storage element 1, the insulator 13 that insulates between the plurality of power storage elements 1 and the holding member 11, and the two adjacent power storage elements 1. A bus bar 14 is also provided. In the power storage device 10 of the present embodiment, the plurality of power storage elements 1 are arranged in a state where the long wall portions 313 of the case 3 face each other.

  Adjacent member 12 is insulative and has a plate-like shape disposed between power storage elements 1 adjacent in the X-axis direction and between power storage element 1 and holding member 11 (specifically, termination member 111). It is a member. By disposing the adjacent member 12, a predetermined interval (creeping distance or the like) is ensured between the power storage elements 1 aligned in the X-axis direction and between the power storage element 1 aligned in the X-axis direction and the holding member 11. Is done. The adjacent member 12 of this embodiment is made of resin.

  The holding member 11 surrounds the plurality of power storage elements 1 and the plurality of adjacent members 12, thereby holding the plurality of power storage elements 1 and the plurality of adjacent members 12 together. The holding member 11 is made of a conductive member such as metal. Specifically, the holding member 11 includes a pair of termination members 111 disposed so that the plurality of power storage elements 1 are positioned therebetween in the X-axis direction, and a pair of the holding members 11 facing the plurality of power storage elements 1 in the Y-axis direction. A pair of opposing members 112 that connect the terminal members 111 of each other.

  Each of the pair of termination members 111 is a plate-like member that extends in the YZ plane (a plane that includes the Y-axis direction and the Z-axis direction).

  Each of the pair of opposing members 112 extends in the Y-axis direction and is disposed with a gap in the Z-axis direction, and a pair of first connections that connect ends of the pair of beam parts 1121. Part 1122 and a second connecting part 1123 that connects the pair of beam parts 1121 at an intermediate position in the Y-axis direction. The matching terminal member 111 is connected by the opposing member 112 configured in this manner, so that the holding member 11 presses the plurality of power storage elements 1 from the outside in the Y-axis direction (the direction in which the pair of long wall portions 313 are arranged). To do. That is, in the power storage device 10, a force sandwiched in the Y-axis direction is applied to each of the plurality of power storage elements 1 held by the holding member 11 (specifically, the case 3 of each power storage element 1).

  The insulator 13 has an insulating property. The insulator 13 is disposed between the opposing member 112 and the plurality of power storage elements 1 arranged in the Y-axis direction. Specifically, the insulator 13 covers a region of the holding member 11 that faces at least the plurality of power storage elements 1. Thereby, the insulator 13 insulates between the holding member 11 and the plurality of power storage elements 1.

  The bus bar 14 is configured by a plate-like member having conductivity such as metal, and electrically connects the external terminals 4 of the energy storage device 1. A plurality of bus bars 14 (the number corresponding to the plurality of power storage elements 1) are provided in the power storage device 10. The plurality of bus bars 14 of the present embodiment connects (conducts) all of the plurality of power storage elements 1 included in the power storage device 10 in series.

  According to the power storage device 10 described above, when a force is applied to each power storage element 1 in the Y-axis direction, the distance between the pair of long wall portions 313 on the closing portion 311 side tends to be small. By pressing each power storage element 1 from the outside in the Y-axis direction, the electrode body 2 is pressed over a wide range of the case 3 (long wall portion 313) of each power storage element 1. Thereby, in the electrical storage apparatus 10 of this embodiment, the performance fall resulting from expansion | swelling of the electrode body 2 is suppressed.

  In addition, the electrical storage element and electrical storage apparatus of this invention are not limited to the said embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention. For example, the configuration of another embodiment can be added to the configuration of a certain embodiment, and a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of an embodiment can be deleted.

  In the closing part 311 in the electricity storage device 1 of the above embodiment, the flat plate part 3110 is disposed on the inner side (opening peripheral part 34 side) of the case 3 from the peripheral edge of the trunk part 312 on the closing part 311 side (FIG. 3 and FIG. 3). 7) is not limited to this configuration. For example, as shown in FIG. 10, the flat plate portion 3110 may be disposed outside the case 3 from the periphery of the body portion 312, that is, the first intermediate ridge line 3115 </ b> A may be disposed outside the periphery of the body portion 312. .

  Moreover, although the bending part of the obstruction | occlusion part 311 of the said embodiment contains the 1st intermediate | middle bending part 3115 and the 1st end part bending part 3114, it is not limited to this structure. For example, as shown in FIG. 11, the bent portion of the closing portion 311 may include only the first end bent portion 3114 (that is, the configuration without the first intermediate bent portion 3115). Even in such a configuration, when a force is applied to the electricity storage element 1 (case 3) from the outside in the Y-axis direction, the first end bent portion 3114 follows the ridge line (first end ridge line) 3114A by the force. Therefore, the distance between the ends of the pair of long wall portions 313 on the closing portion 311 side tends to be small.

  In the case 3 of the above-described embodiment, the first intermediate ridge line 3115A and the first end ridge line 3114A are formed by bending (bending) the closing portion 311. However, the present invention is not limited to this configuration. For example, as shown in FIG. 12, the ridgeline r may be formed by curving the closing portion 311 or the like. In this case, the line connecting the tops of the curved portions (in the example of FIG. 12, the position farthest in the Z-axis direction from the periphery of the trunk portion 312 in the cross section in the YZ plane direction) is the ridge line (first intermediate ridge line). r.

  Moreover, in the case 3 of the said embodiment, although the 1st intermediate | middle bending part 3115 and the 1st end part bending part 3114 are formed in the obstruction | occlusion part 311 and its peripheral part, it is not limited to this structure. For example, the first intermediate bending portion 3115 and the first end bending portion 3114 may be formed on the cover plate 32 and the peripheral edge thereof.

  In the electricity storage device 1 of the above embodiment, the electrode body 2 is a so-called wound electrode body in which the strip-shaped electrodes 23 and 24 are wound, but is not limited to this configuration. The electrode body 2 may be a so-called stacked electrode body in which sheet-like electrodes are stacked. Further, the electrode body 2 may be one in which at least one of the positive electrode 23, the negative electrode 24, and the separator 25 is spelled (bellows-shaped). For example, specifically, as shown in FIG. 13, the electrode 2 may have a structure in which long separators 25 are folded and sheet-like positive electrodes 23 and negative electrodes 24 are alternately arranged in the bent portions. Further, as shown in FIG. 14, the electrode 2 is formed by folding a long negative electrode 24, disposing a sheet-like positive electrode 23 in the bent portion and separating the positive electrode 23 and the negative electrode 24 from each other. May be arranged. In addition, as shown in FIG. 15, all of the positive electrode 23, the negative electrode 24, and the separator 25 may be long and spelled in the electrode 2.

  Moreover, in the electrical storage element 1 of the said embodiment, although the one electrode body 2 is accommodated in the case 3 in the state which made the winding center axis C direction correspond with a Z axis | shaft, it is not limited to this structure. The plurality of electrode bodies 2 may be accommodated in the case 3 in a state in which the winding center axis C is aligned with the Z axis and the winding center axes C are aligned with each other.

  Moreover, in the electrical storage element 1 of the said embodiment, the 1st intermediate | middle bending part 3115, the 1st end part bending part 3114, the 2nd end part bending part 3116, the 2nd intermediate bending part 3117 grade | etc., Are the obstruction | occlusion part 311 and its periphery However, the present invention is not limited to this configuration. The first intermediate bent portion 3115, the first end bent portion 3114, the second end bent portion 3116, the second intermediate bent portion 3117, etc. are the cover plate 32 and its peripheral portion, the short wall portion 314 and its peripheral portion. Etc. may be formed.

  In the electricity storage device 1 of the above embodiment, two first intermediate bending portions 3115A are arranged in the closing portion 311. However, the configuration is not limited to this. One first intermediate bending portion 3115A may be disposed in the closing portion 311 or three or more.

  Moreover, in the said embodiment, although the case where an electrical storage element was used as a nonaqueous electrolyte secondary battery (for example, lithium ion secondary battery) which can be charged / discharged was demonstrated, the kind and magnitude | size (capacity | capacitance) of an electrical storage element are arbitrary. It is. Moreover, in the said embodiment, although the lithium ion secondary battery was demonstrated as an example of an electrical storage element, it is not limited to this. For example, the present invention can be applied to various secondary batteries, other primary batteries, and power storage elements of capacitors such as electric double layer capacitors.

  In the power storage device 10 of the above embodiment, all of the power storage elements 1 have at least one of the first intermediate bent portion 3115A and the first end bent portion 3114, but the configuration is not limited to this. In the power storage device 10 including a plurality of power storage elements, at least one power storage element 1 may have at least one of the first intermediate bent portion 3115A and the first end bent portion 3114.

  DESCRIPTION OF SYMBOLS 1 ... Power storage element, 2 ... Electrode body, 201, 202 ... Curved part, 201A, 202B ... Part corresponding to the curved part in metal foil, 203 ... Flat part, 203A, 203B ... Part corresponding to the flat part in metal foil, DESCRIPTION OF SYMBOLS 21 ... Core, 22 ... Laminated body, 23 ... Positive electrode (electrode), 231 ... Metal foil, 232 ... Positive electrode active material layer (active material layer), 24 ... Negative electrode (electrode), 241 ... Metal foil, 242 ... Negative electrode active Material layer (active material layer), 25 ... separator, 26A ... uncoated laminate portion, 26B ... uncoated laminate portion, 3 ... case, 31 ... case main body, 311 ... closed portion, 3110 ... flat plate portion, 3111 ... first slope Part 3112 ... second inclined part 3114 ... first end bending part 3114A ... first end ridge line 3115 ... first intermediate bending part 3115A ... first intermediate ridge line 3116 ... second end bending part, 3116A ... Second end ridge 3117 ... second intermediate bent portion, 3117A ... second intermediate ridge line, 312 ... barrel, 313 ... long wall portion, 314 ... short wall portion, 32 ... lid plate, 325 ... injection hole, 326 ... injection stopper, 33 DESCRIPTION OF SYMBOLS ... Internal space 34 ... Opening edge part, 4 ... External terminal, 41 ... Surface, 5 ... Current collector, 51 ... First connection part, 52 ... Second connection part, 6 ... Insulating member, 10 ... Power storage device, 11 DESCRIPTION OF SYMBOLS ... Holding member, 111 ... Termination member, 112 ... Opposing member, 1121 ... Beam part, 1122 ... First connection part, 1123 ... Second connection part, 12 ... Adjacent member, 13 ... Insulator, 14 ... Bus bar, C ... Winding Central axis

Claims (6)

An electrode body having stacked electrodes;
A case in which the electrode body is accommodated,
The case includes a pair of opposing wall portions facing the outer surface of the electrode body side by side in the stacking direction of the electrodes, and a connection wall portion connecting the opposing end portions of the opposing wall portion,
The storage wall element has a ridge line extending in a direction intersecting with a direction in which the pair of opposing wall sections are arranged, and a bending section that can be bent and deformed along the ridge line. The connection wall portion includes a pair of inclined portions including a proximal end and a distal end opposite to the proximal end and extending in a direction intersecting the opposing wall portion,
The power storage element according to claim 1, wherein the bent portion includes an end bent portion that connects a base end of the inclined portion and the opposing wall portion. The connection wall portion is disposed between tips of the pair of inclined portions, and has a flat plate portion that extends in a direction orthogonal or substantially orthogonal to the opposing wall portion,
The power storage element according to claim 2, wherein the bent portion includes a pair of intermediate bent portions that connect a peripheral edge of the flat plate portion and a tip of the inclined portion. The electrode is wound in a stacked state,
The electrical storage element according to any one of claims 1 to 3, wherein the electrode body is accommodated in the case in a state in which one end portion in a winding central axis direction faces the connection wall portion. The electrode has a metal foil and an active material layer laminated on the metal foil,
The power storage element according to claim 4, wherein the active material layer is disposed up to the one end of the electrode body in the winding central axis direction. A plurality of power storage elements according to any one of claims 1 to 5,
A holding member for holding the plurality of power storage elements,
The plurality of power storage elements are stacked in the direction in which the pair of opposing wall portions are arranged in a state where adjacent power storage elements face each other.
The holding member presses the plurality of power storage elements from the outside in the direction in which the pair of opposed wall portions are arranged.

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