JP2021044081A - Power storage element - Google Patents

Abstract

To provide a power storage element that is provided with a plurality of winding type electrode bodies that are collected by a piece-shaped current collecting tab, and in which the electrode bodies are less likely to open.SOLUTION: A power storage element includes a plurality of electrode bodies 2 each including a wound strip-shaped electrode main body 21 and a piece-shaped current collecting tab that conducts with the electrode main body, and a case in which the plurality of adjacent electrode bodies are housed so as to face each other with the winding axes of the electrode main bodies oriented in the same direction, and some of the electrode bodies 2A from among the plurality of electrode bodies have different winding directions of the electrode main body from the remaining electrode bodies 2B.SELECTED DRAWING: Figure 7

Description

The present invention relates to a power storage element including a plurality of winding type electrode bodies.

Conventionally, a non-aqueous electrolyte secondary battery including a plurality of wound electrode bodies has been known (see Patent Document 1). This non-aqueous electrolyte secondary battery includes two flat wound electrode bodies, a square exterior body accommodating the two wound electrode bodies, and a current collector connected to the wound electrode body.

In each wound electrode body, the positive electrode plate and the negative electrode plate are wound in a state of being insulated from each other via a separator. Each wound electrode body is provided with a positive electrode core body exposed portion in which a plurality of sheets are laminated at one end in the winding axis direction, and a plurality of negative electrode core bodies are exposed at the other end in the winding axis direction. It has a part. These two wound electrode bodies are housed in the square outer body so that the winding shafts are parallel to the bottom of the square outer body. Specifically, the two wound electrode bodies are housed in the square exterior body in a state where the positive electrode plate and the negative electrode plate have the same winding direction and their peripheral surfaces are in contact with each other. Further, in each wound electrode body, the exposed portion of the positive electrode core body in which a plurality of sheets are laminated is electrically connected to the positive electrode terminal via a positive electrode current collector made of a bent metal plate material, and the plurality of sheets are laminated. The exposed portion of the negative electrode core is electrically connected to the negative electrode terminal via a negative electrode current collector made of a bent metal plate material.

In such a non-aqueous electrolyte secondary battery, a configuration may be adopted in which current collection from a plurality of wound electrode bodies is performed by a flake-shaped current collecting tab extending from each wound electrode body. In the case of this configuration, each wound electrode body is formed by a current collector composed of a bent metal plate or the like at both ends (a plurality of laminated positive electrode cores exposed portions and a plurality of laminated positive electrode cores). The exposed part) is not firmly fixed.

Therefore, when vibration or acceleration in a predetermined direction is applied to the non-aqueous electrolyte secondary battery during use, etc., due to inertial force or the like, the portion on the winding center side of the wound electrode body (positive electrode plate and negative electrode in the wound state). Plate part: see reference numeral 501 in FIG. 12) tries to separate from the outer peripheral side part (positive electrode plate or negative electrode plate: see reference numeral 502 in FIG. 12) (see arrow γ in FIG. 12: hereinafter, simply “electrode body”. It is called "opening of"). In particular, in a flat wound electrode body, the opening of the electrode body becomes remarkable.

As described above, when the electrode body is opened in the wound electrode body, the distance between the electrode plates (distance between the electrode plates) changes, and the performance of the non-aqueous electrolyte secondary battery deteriorates.

Japanese Unexamined Patent Publication No. 2017-228542

Therefore, an object of the present embodiment is to provide a power storage element including a plurality of winding type electrode bodies that collect electricity by a flake-shaped current collection tab, and the electrode bodies are unlikely to open. To do.

The power storage element of this embodiment is
A band-shaped electrode body that is wound, and a plurality of electrode bodies that each have a piece-shaped current collecting tab that conducts with the electrode body.
A case is provided in which the plurality of electrode bodies are housed so that adjacent electrode bodies face each other so that the winding axes of the electrode bodies are oriented in the same direction and their peripheral surfaces are in contact with each other.
Some of the plurality of electrode bodies have different winding directions from the remaining electrode bodies.

In electrode bodies with different winding directions of the electrode body, the direction in which the winding center side portion (the wound electrode) tends to move with respect to the outer peripheral side electrode is opposite to each other and presses against each other (Fig.). 7), even if the power storage element is subjected to vibration in a predetermined direction to open the electrode body, the opening of the electrode body is suppressed.

In the power storage element,
The case may accommodate the plurality of electrode bodies so that the winding directions of the electrode bodies of the adjacent electrode bodies are different from each other.

According to such a configuration, in the plurality of electrode bodies housed in the case, the opening of the electrode bodies is suppressed between the adjacent electrode bodies, whereby the opening of each electrode body is suppressed.

Further, in the power storage element,
The case accommodates at least one set of electrode bodies when two sets of electrode bodies arranged in different winding directions of the electrode body are used as a set of electrode bodies.
In the set of electrode bodies, each electrode body may be arranged so that the outermost end portion of the electrode body is located outside the alignment direction of the two electrode bodies in the set of electrode bodies.

According to such a configuration, the opening of the electrode bodies is suppressed in the set of the electrode bodies.

Further, in the power storage element,
The current collecting tab extends from the outermost peripheral end of the wound electrode body.
Each current collecting tab of the plurality of electrode bodies may be bundled.

In a power storage element having a plurality of electrode bodies, in a configuration in which current collecting tabs extending from the outermost peripheral end of the wound electrode body are bundled, when vibration or the like in a predetermined direction is applied, The portion of the electrode body on the winding center side is easy to move with respect to the electrode on the outer peripheral side, so that the adjacent electrode body is pushed and a load is easily applied to the current collecting tab (see FIG. 10). However, according to the above configuration, the electrode bodies having different winding directions of the electrode bodies are arranged so as to be in contact with each other, and the opening of each electrode body is suppressed, so that the load on the current collecting tab is suppressed.

Further, in the power storage element,
The electrode body has a strip-shaped conductive layer and an active material layer to be superimposed on the conductive layer.
At the portion of the electrode body that constitutes the outermost circumference of the electrode body, the active material layer is not laminated on the surface facing the outside of the conductive layer.
Adjacent electrode bodies in the plurality of electrode bodies may be brought into contact with each other where the active material layers are not laminated.

The active material layer laminated on the outer surface of the conductive layer at the portion of the electrode body forming the outermost periphery of the electrode body does not contribute to the charging and discharging of the power storage element. Therefore, as in the above configuration, the battery capacity is reduced by bringing the adjacent electrode bodies into contact with each other without laminating the active material layer on the outer surface of the conductive layer at the portion of the electrode body constituting the outermost periphery. It is possible to save space for arranging a plurality of electrode bodies (save space for the thickness of the active material layer), and thereby improve the energy density of the power storage element.

Based on the above, according to the present embodiment, there is provided a power storage element including a plurality of winding type electrode bodies that collect electricity by a flake-shaped current collection tab, and the electrode body is unlikely to open. Can be done.

FIG. 1 is a perspective view of a power storage element according to the present embodiment. FIG. 2 is an exploded perspective view of the power storage element. FIG. 3 is a cross-sectional view taken along the line III-III of FIG. FIG. 4 is a perspective view of an electrode body included in the power storage element. FIG. 5 is a diagram for explaining the configuration of the electrode body. FIG. 6 is a diagram for explaining a positive electrode, a negative electrode, and a separator. FIG. 7 is a schematic view showing the arrangement of electrode bodies having different winding directions of the electrodes. FIG. 8 is a schematic view showing the arrangement of electrodes according to another embodiment. FIG. 9 is a diagram for explaining an electrode body according to another embodiment. FIG. 10 is a schematic diagram for explaining a load applied to the current collecting tab when vibration or the like is applied to the power storage element in a configuration in which a plurality of electrode bodies having the same winding direction are lined up. FIG. 11 is a schematic view of a power storage device including the power storage element. FIG. 12 is a diagram for explaining a movement in which a portion on the winding center side tends to be separated from an electrode on the outer peripheral side due to vibration or the like in a plurality of winding electrode bodies having the same winding direction.

Hereinafter, an embodiment of the power storage element according to the present invention will be described with reference to FIGS. 1 to 7. The power storage element includes a primary battery, a secondary battery, a capacitor, and the like. In the present embodiment, a rechargeable secondary battery will be described as an example of the power storage element. The name of each component (each component) of the present embodiment is that of the present embodiment, and may be different from the name of each component (each component) in the background technology.

The power storage element of this embodiment is a non-aqueous electrolyte secondary battery. More specifically, the power storage element is a lithium ion secondary battery that utilizes electron transfer generated by the movement of lithium ions. This type of power storage element supplies electrical energy. The power storage element may be used alone or in combination of two or more. Specifically, the power storage element is used alone when the required output and the required voltage are small. On the other hand, when at least one of the required output and the required voltage is large, the power storage element is used in the power storage device in combination with another power storage element. In the power storage device, the power storage element used in the power storage device supplies electrical energy.

As shown in FIGS. 1 to 3, the power storage element includes a so-called winding type plurality of (four in the example of the present embodiment) electrode bodies 2 and a case 3 accommodating the plurality of electrode bodies 2. .. Further, the power storage element 1 is attached to the case 3 with at least a part exposed, or connects an external terminal 4 composed of at least a part of the case 3 to the plurality of electrode bodies 2 and the external terminal 4. An insulating member 6 or the like arranged between the current collector 5 and the plurality of electrode bodies 2 and the case 3 is also provided. The external terminal 4 of this embodiment is attached to the case 3.

As shown in FIGS. 4 and 5, each of the plurality of electrode bodies 2 is configured by winding an electrode 20 having a conductive layer 211 and an active material layer 212 superimposed on the conductive layer 211. There is. In each electrode body 2 of the present embodiment, the electrode 20 is wound so as to be a flat wound body. That is, each electrode body 2 connects the ends of the pair of flat portions 2F facing each other across the winding shaft C of the electrode body 2 and the ends of the pair of flat portions 2F, and faces each other with the winding shaft C interposed therebetween. It has a pair of curved portions 2C. The plurality of electrode bodies 2 of the present embodiment include two types of electrode bodies (first electrode body 2A, second electrode body 2B: see FIG. 2) in which the winding directions of the electrodes 20 are different. In the following, the direction in which the pair of curved portions 2C face each other is defined as the X-axis direction in the Cartesian coordinate system, the direction in which the pair of flat portions 2F face each other is defined as the Y-axis direction in the Cartesian coordinate system, and the extending direction of the winding axis C is orthogonal. The Z-axis direction of the coordinate system.

In each electrode body 2, the active material layer 212 is not overlapped on the outer surface of the conductive layer 211 at the outermost _{peripheral portion α 0 (see FIG. 6) of the wound electrode 20, and the conductive layer 211 is exposed.} ing.

The electrode 20 has a band-shaped electrode body 21 and a flake-shaped current collecting tab 22 that conducts with the electrode body 21. The current collecting tab 22 of this embodiment extends from the conductive layer 211 of the electrode body 21.

Specifically, the electrode 20 has a band-shaped electrode body 21 that is wound, and at least one current collecting tab 22 that extends from one end (long side) of the electrode body 21 in the short direction. The electrode 20 includes a positive electrode 23 and a negative electrode 24. Lithium ions move between the positive electrode 23 and the negative electrode 24 to charge and discharge the power storage element 1. The specific configurations of the positive electrode 23 and the negative electrode 24 are as follows.

The positive electrode 23 has a metal foil 231 and a positive electrode active material layer 232 superimposed on the metal foil 231. The metal foil 231 has a strip-shaped foil main body 2311 which is a conductive layer 211 of the positive electrode 23, and a rectangular positive electrode current collecting tab 2312 extending from one end of the foil main body 2311 in the short direction. The metal foil 231 of the present embodiment has a plurality of positive electrode current collecting tabs 2312, and these plurality of positive electrode current collecting tabs 2312 have an electrode body 21 (the positive electrode body 230 described later) at one end of the foil body 2311 in the short direction. ) Are arranged at positions aligned in the Y-axis direction when wound (see FIG. 4). The plurality of positive electrode current collecting tabs 2312 of the first electrode body 2A and the plurality of positive electrode current collecting tabs 2312 of the second electrode body 2B are such that the first electrode body 2A and the second electrode body 2B are Y. When they are lined up in the axial direction, they are arranged at positions that line up in the Y-axis direction (positions that overlap when viewed from the Y-axis direction). Further, the metal foil 231 of the present embodiment is, for example, an aluminum foil.

In the positive electrode 23, the positive electrode active material layer 232 is laminated on both sides of the foil main body 2311, and these foil main bodies 2311 and the positive electrode active material layer 232 superposed on the foil main body 2311 form the positive electrode main body 230 of the positive electrode 23. (See Fig. 6).

Specifically, in the positive electrode body 230, the outermost peripheral portion on the surface of the foil body 2311 facing outward in the wound state (that is, the surface of the electrode body 2 facing the side opposite to the winding axis C side: the outer surface) 2311A. The positive electrode active material layer 232 is overlaid on the entire area except _{α 1.} Further, in the positive electrode body 230, on the surface of the foil body 2311 facing inward in the wound state (that is, the surface of the electrode body 2 facing the winding axis C side: inner surface) 2311B, the positive electrode active material layer covers the entire area. 232 are stacked.

Further, in the positive electrode main body 230, the positive electrode active material layer 232 is not overlapped on the outer surface 2311A of the positive _{electrode main body 230 at the outermost peripheral portion α 1 (see FIG. 4).} In the electrode body 2 of the present embodiment, the positive electrode 23 is located on the outermost circumference. That is, in the electrode body 2 of the present embodiment, the outermost peripheral portion α ₀ of the electrode 20 constituting the electrode body 2 is composed of the outermost outer peripheral portion α ₁ of the positive electrode 23. Therefore, the outer peripheral surface of the electrode body 2 is composed of the foil body 2311 (conductive layer 211). Further, the positive electrode 23 in the electrode body 2 is _{wound so that the end portion of the outermost peripheral portion α 1} (the end in the longitudinal direction of the positive electrode 23) is located at the end portion in the X-axis direction of the flat portion 2F (FIG. 4).

In the above positive electrode 23, the portion corresponding to the electrode main body 21 of the electrode 20 is the positive electrode main body 230, and the portion corresponding to the current collecting tab 22 of the electrode 20 is the positive electrode current collecting tab 2312.

The negative electrode 24 has a metal foil 241 and a negative electrode active material layer 242 superimposed on the metal foil 241. The metal foil 241 has a strip-shaped foil body 2411 which is a conductive layer 211 of the negative electrode 24, and a rectangular negative electrode current collecting tab 2412 extending from one end of the foil body 2411 in the short direction. The metal foil 241 of the present embodiment has a plurality of negative electrode current collecting tabs 2412, and these negative electrode current collecting tabs 2412 have an electrode body 21 (negative electrode body 240 described later) at one end of the foil body 2411 in the short direction. They are arranged at positions that line up in the Y-axis direction when they are wound (see FIG. 4). The plurality of negative electrode current collecting tabs 2412 of the first electrode body 2A and the plurality of negative electrode current collecting tabs 2412 of the second electrode body 2B are such that the first electrode body 2A and the second electrode body 2B are Y. When they are lined up in the axial direction, they are arranged at positions that line up in the Y-axis direction (positions that overlap when viewed from the Y-axis direction). Further, the metal leaf 241 of the present embodiment is, for example, a copper foil.

In the negative electrode 24, the negative electrode active material layer 242 is laminated on both sides of the foil main body 2411, and these foil main bodies 2411 and the negative electrode active material layer 242 superposed on the foil main body 2411 form the negative electrode main body 240 of the negative electrode 24. (See Fig. 6).

In the electrode body 2 of the present embodiment, the innermost peripheral portion β ₂ of the negative electrode 24 is arranged inside _{the innermost peripheral portion β 1 of the positive electrode 23.} That is, in the electrode body 2 of the present embodiment, the innermost peripheral portion β ₀ of the electrode 20 constituting the electrode body 2 is composed of the innermost peripheral portion β ₂ of the negative electrode 24.

In the above negative electrode 24, the portion corresponding to the electrode body 21 of the electrode 20 is the negative electrode body 240, and the portion corresponding to the current collecting tab 22 of the electrode 20 is the negative electrode current collecting tab 2412.

In each 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 of being insulated by the separator 25. That is, in each electrode body 2 of the present embodiment, the positive electrode 23, the negative electrode 24, and the separator 25 are in a laminated state.

The separator 25 is an insulating member and is arranged between the positive electrode 23 and the negative electrode 24. As a result, in the electrode body 2, the positive electrode 23 and the negative electrode 24 are insulated from each other. Further, the separator 25 holds the electrolytic solution in the case 3. As a result, when the power storage element 1 is charged and discharged, lithium ions can move between the positive electrode 23 and the negative electrode 24, which are alternately laminated with the separator 25 in between. Further, the width direction (short direction) of the separator 25 is larger than the width direction of the positive electrode 23 and the negative electrode 24.

The separator 25 is strip-shaped and is made of, for example, a porous membrane such as polyethylene, polypropylene, cellulose, or polyamide. In the separator 25 of the present embodiment _{, an inorganic layer containing inorganic particles such as SiO 2} particles, Al ₂ O ₃ particles, and boehmite (alumina hydrate) is provided on a base material formed of a porous film. Is formed of. The base material of the separator 25 of the present embodiment is formed of, for example, polyethylene.

As shown in FIGS. 1 to 3, the case 3 has a case main body 31 having an opening and a lid plate 32 that closes (closes) the opening of the case main body 31. The case 3 is made of a metal that is resistant to the electrolyte. Case 3 of the present embodiment is formed of, for example, aluminum or an aluminum-based metal material such as an aluminum alloy.

The electrolytic solution is a non-aqueous electrolyte solution. The electrolytic solution is obtained by dissolving an electrolyte salt in an organic solvent. The organic solvent is, for example, cyclic carbonates such as propylene carbonate and ethylene carbonate, and chain carbonates such as dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Electrolyte salts are LiClO ₄ , LiBF _{4 , LiPF 6} , and the like. _{The electrolytic solution of the present embodiment contains 1 mol / L LiPF 6} in a mixed solvent prepared by adjusting ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a ratio of ethylene carbonate: dimethyl carbonate: ethyl methyl carbonate = 3: 2: 5. Is dissolved.

The case body 31 includes a plate-shaped closing portion 311 and a tubular body portion (peripheral wall) 312 connected to the peripheral edge of the closing portion 311.

The closing portion 311 is located at the lower end of the case body 31 when the case body 31 is arranged with the opening facing upward (that is, becomes the bottom wall of the case body 31 when the opening faces upward). ) The part. The closed portion 311 has a rectangular shape when viewed from the normal direction of the closed portion 311.

The body portion 312 has a square tube shape, more specifically, a flat square tube shape. The body portion 312 has a pair of long wall portions 313 extending from the long side at the peripheral edge of the closed portion 311 and a pair of short wall portions 314 extending from the short side at the peripheral edge of the closed portion 311. That is, the pair of long wall portions 313 face each other with an interval in the Y-axis direction (specifically, the interval corresponding to the short side at the peripheral edge of the closing portion 311), and the pair of short wall portions 314 are spaced in the X-axis direction. (Specifically, they face each other with an interval corresponding to the long side at the peripheral edge of the closed portion 311). A square tubular body portion 312 is formed by connecting the end portions of the short wall portion 314 corresponding to the pair of long wall portions 313 (specifically, facing each other in the Y-axis direction).

As described above, the case body 31 has a square tube shape (that is, a bottomed square tube shape) in which one end in the opening direction (Z-axis direction) is closed.

The lid plate 32 is a plate-shaped member that closes the opening of the case body 31. The lid plate 32 of the present embodiment is a rectangular plate material long in the X-axis direction when viewed from the Z-axis direction. In the lid plate 32, the peripheral edge portion of the lid plate 32 is overlapped with the opening peripheral edge portion 34 of the case main body 31 so as to close the opening of the case main body 31. The boundary portion between the lid plate 32 and the case body 31 is welded in a state where the opening peripheral edge portion 34 and the lid plate 32 are overlapped with each other, whereby the case 3 is formed.

In the case 3 composed of the case body 31 and the lid plate 32, adjacent electrode bodies 2 have winding axes C oriented in the Z-axis direction (same direction) and their outer peripheral surfaces (peripheral surfaces) are in contact with each other. As described above, a plurality of electrode bodies 2 are accommodated. Specifically, in the plurality of electrode bodies 2, the flat portion 2F of each electrode body 2 is parallel (substantially parallel) to the long wall portion 313, and each of the pair of curved portions 2C of each electrode body 2 is parallel to the short wall portion 314. It is housed in the case 3 in a state of being covered with the insulating member 6 so as to face each other (see FIGS. 2 and 3). At this time, a part of the electrode bodies (first electrode body) 2A of the plurality of electrode bodies 2 is the remaining electrode body (second electrode body) 2B and the electrode 20 (specifically, the electrode body 21). The winding direction is different. In the power storage element 1 of the present embodiment, as shown in FIG. 7, the winding directions of the electrode bodies 21 of the adjacent electrode bodies 2 are different from each other. That is, in the plurality of electrode bodies 2 (first electrode body 2A and second electrode body 2B), the first electrode body 2A and the second electrode body 2B alternate in the Y-axis direction inside the case 3. They are arranged side by side.

Further, in the power storage element 1 of the present embodiment, in each of the electrode bodies 2A and 2B, the end on the winding end side of the electrode 20 (the positive electrode 23 in the example of the present embodiment) in the electrode bodies 2A and 2B is in the X-axis direction. It is housed in the case 3 so as to be located on the same side (the left side in the example shown in FIG. 2). Further, in the electrode bodies 2A and 2B arranged at both ends in the Y-axis direction of the plurality of electrode bodies 2A and 2B, the end of the electrode 20 on the winding end side is outside in the Y-axis direction (in the electrode body 2A at the left end in FIG. 7). The electrode bodies 2A and 2B are housed in the case 3 so as to be located on the left side and the right side of the rightmost electrode body 2B, respectively.

Further, the case 3 accommodates a plurality of electrode bodies 2 (first electrode body 2A and second electrode body 2B) in a state where the whole is pressed (pressed) in the Y-axis direction. Therefore, the adjacent electrode bodies 2 are brought into close contact with each other on their outer peripheral surfaces. That is, the adjacent first electrode body 2A and the second electrode body 2B are the metal foils 231 of the positive electrode 23 (specifically, the foil bodies (conductive layers) 2311 exposed at _{the outermost peripheral portion α 1 of the positive electrode 23).} Are in contact with each other. As a result, the positive electrodes 23 of the adjacent electrode bodies 2 are electrically connected to each other.

The positive electrode current collector tabs 2312 of the plurality of electrode bodies 2 are bundled so as to be conductive with each other, and are connected to the external terminal 4 via the current collector 5. Further, the negative electrode current collector tabs 2412 of the plurality of electrode bodies 2 are also bundled so as to be conductive with each other, and are connected to the external terminal 4 via the current collector 5 (see FIG. 3). The bundle of the positive electrode current collector tab 2312 and the bundle of the negative electrode current collector tab 2412 of the present embodiment are connected to the current collector 5 by welding.

The external terminal 4 is a portion electrically connected to an external terminal of another power storage element, an external device, or the like. Therefore, 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 insulating member 6 is arranged between the case 3 (specifically, the case body 31) and the plurality of electrode bodies 2. The insulating member 6 is formed in a bag shape as shown in FIG. 2 by bending a sheet-shaped member having an insulating property cut into a predetermined shape.

In the electrode bodies 2A and 2B having different winding directions of the electrodes 20 as described above, the portion 201 on the winding center side (the electrode in the wound state) 201 is the electrode on the outer peripheral side (specifically, the electrode 20). (In the example of the present embodiment, the positive electrode 23) includes the end in the longitudinal direction and constitutes the flat portion 2F) Since the directions of movement with respect to 202 are opposite to each other and pressed against each other (arrow γ in FIG. 7). And arrow σ), even if the power storage element 1 is subjected to vibration in the Y-axis direction (predetermined direction) to open the electrode bodies 2A and 2B, the opening of the electrode bodies 2A and 2B is suppressed, respectively.

The active material layer laminated on the outer surface of the metal foil in the electrode body (portion of the electrode body) constituting the outermost circumference of the electrode body does not contribute to charging / discharging of the power storage element. Therefore, like the power storage element 1 of the present embodiment, the adjacent electrode bodies 2 in the plurality of electrode bodies 2 are placed on the outer surface of the conductive layer 211 at the portion of the electrode body 21 forming the outermost periphery of the electrode body 2. By abutting each other in a state where the active material layers are not laminated (in the example of this embodiment, the foil bodies 2311 (conductive layers 211) are brought into contact with each other), a space for arranging a plurality of electrode bodies 2 without reducing the battery capacity. Space saving (space saving by the thickness of the active material layer) can be achieved. As a result, the energy density of the power storage element 1 can be improved.

Further, the adjacent electrode bodies 2 abut (closely) the foil main body 2311 (conductive layer 211) constituting the outer peripheral surface of the electrode body 2, so that the adjacent electrode bodies 2 are electrically connected to each other. , The bias of the current flowing through the plurality of electrode bodies 2 can be suppressed.

The power storage element of the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. In addition, some of the configurations of certain embodiments can be deleted.

The electrode body 2 of the above embodiment is a flat winding type electrode body, but is not limited to this configuration. The electrode body 2 may be a columnar winding type electrode body.

The specific arrangement of the plurality of electrode bodies 2 inside the case 3 is not limited. The winding direction of the electrode 20 of at least one electrode body (for example, the first electrode body 2A) of the plurality of electrode bodies 2 housed inside the case 3 is the remaining electrode body (for example, the second electrode body 2A). It suffices if it is different from the winding direction of the electrode 20 of the electrode body 2B). Even with this configuration, when vibration or the like in the X-axis direction (predetermined direction) is applied to the power storage element 1, at least two adjacent electrode bodies 2A and 2B having different winding directions of the electrode 20 are on the winding center side. Even if the portion 201 tries to move with respect to the electrode 202 on the outer peripheral side, the portions 201 on the winding center side are pressed against each other, so that the opening of the electrode bodies 2A and 2B is suppressed, respectively.

For example, in the power storage element 1 of the above embodiment, electrode bodies (first electrode body 2A and second electrode body 2B) having different winding directions of the electrodes 20 are arranged so as to be alternately arranged in the Y-axis direction. However, it is not limited to this configuration.

As shown in FIG. 8, a plurality of electrode body sets 2P may be arranged with the first electrode body 2A and the second electrode body 2B as the electrode body set 2P. In this case, in the electrode body set 2P, the outermost end portion (or the outer peripheral side electrode 202 in the electrode bodies 2A and 2B) of the electrode 20 (electrode body 21) is the two electrode bodies in the electrode body set 2P. The electrode bodies 2A and 2B are arranged so as to be located outside the arrangement direction (Y-axis direction) of 2A and 2B, respectively. According to such a configuration, in the set 2P of each electrode body, the opening of the two electrode bodies 2A and 2B constituting the set P of the electrode body is suppressed.

In this configuration, when the number of electrode bodies 2 is odd, the rows of electrode bodies 2 in which the electrode bodies 2 (for example, the electrode bodies 2B arranged in the center of FIG. 8) that do not form the set 2P of the electrode bodies are lined up in a row. It is preferable that the electrode body is arranged in the middle portion (between the set 2P of the electrode body). It is sufficient that at least one set of electrode bodies 2P is included in a plurality of electrode bodies 2 housed inside the case 3.

In the power storage element 1 of the above embodiment, the electrode bodies 2 are arranged in a row in the Y-axis direction, but the configuration is not limited to this. The plurality of electrode bodies 2 may be arranged so as to form a plurality of rows.

Further, in the electrode body 2 of the power storage element 1 of the above embodiment, the active material layer 212 is not superposed on the outer surface 2311A of the foil body 2311 at the outermost _{peripheral portion α 0 of the electrode 20, but the configuration is not limited to this.} The active material layer 212 may be superposed on both sides 2311A and 2311B of the foil body 2311 at the outermost peripheral portion α _{0 of the electrode 20.}

Further, at the outermost peripheral portion α ₀ of the electrode 20, the active material layer 212 is not superposed on the outer surface 2311A of the foil main body 2311, and only the binder or a binder to which a conductive auxiliary agent is added is superposed. You may.

The current collecting tab 22 of the above embodiment is integrated with the foil main body 2311, but is not limited to this configuration. The foil body 2311 and the current collecting tab 22 may be separate bodies. In this case, the current collecting tab 22 may be electrically connected to the electrode body 21, and the specific configuration of the connection portion with the electrode body 21 is not limited.

Further, the electrode 20 of the above embodiment has a plurality of current collecting tabs 22, but is not limited to this configuration. The electrode 20 may have a configuration having one current collecting tab 22. Further, although the current collecting tab 22 extends from one end of the foil body 2311 in the lateral direction, it may extend from one end of the foil body 2311 in the longitudinal direction.

Further, in the power storage element 1 of the above embodiment, the plurality of electrode bodies 2A and 2B are provided so that the respective winding shafts C coincide with the directions in which the lid plate 32 of the case 3 and the closing portion 311 of the case body 31 face each other. Is arranged, but is not limited to this configuration. As shown in FIG. 9, a plurality of electrode bodies 2A and 2B may be arranged so that each winding shaft C coincides with the direction in which the pair of short wall portions 314 of the case body 31 face each other. In this case, the current collector tab 22 extends from the outermost peripheral end of the wound electrode body 21, and the current collector tabs 22 of the plurality of electrode bodies 2A and 2B are bundled together. Connected to 5. According to such a configuration, the opening of the electrode bodies 2A and 2B is suppressed, and the load on the current collecting tabs 22 is suppressed. The details are as follows.

As shown in FIG. 10, in the power storage element including the plurality of electrode bodies 2 having the same winding direction, the current collecting tabs 22 extending from the outermost peripheral end of the wound electrode body 21 are bundled. In the configuration in which the electrode body 2 is connected to the current collector in this state, when vibration or the like is applied in the direction in which the electrode bodies 2 are lined up (the left-right direction in FIG. It is easy to open with respect to 202 (arrow a in FIG. 10), so that the adjacent electrode body 2 is pushed and a load is easily applied to the current collecting tab 22. In particular, the portion 201 on the winding center side of each electrode body 2 will open with respect to the electrode body 2 at the farthest end (left end in FIG. 10) in the direction in which the winding center side portion 201 of the electrode body 2 opens. Since the pushing force (arrow b in FIG. 10) is integrated, a large force (arrow c in FIG. 10) is applied, which easily damages the current collecting tab 22 of the electrode body 2. However, by alternately arranging the electrode bodies 2A and 2B having different winding directions of the electrode body 21, the opening of the electrode bodies 2A and 2B can be suppressed, so that the load on the current collecting tab 22 can be suppressed. In particular, in the current collecting tabs 22 of the electrode bodies 2A or 2B arranged at the ends of the electrode bodies 2A and 2B arranged in a row, the effect of load suppression becomes remarkable.

Further, in the above embodiment, the case where the power storage element is used as a chargeable / dischargeable non-aqueous electrolyte secondary battery (for example, a lithium ion secondary battery) has been described, but the type and size (capacity) of the power storage element are arbitrary. Is. Further, in the above embodiment, the lithium ion secondary battery has been described as an example of the power storage element, but the present invention 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.

The power storage element (for example, a battery) 1 may be used in a power storage device (battery module when the power storage element is a battery) 11 as shown in FIG. The power storage device 11 includes at least two power storage elements 1 and a bus bar member 12 that electrically connects two (different) power storage elements 1 to each other. In this case, the technique of the present invention may be applied to at least one power storage element 1.

1 ... Power storage element, 2 ... Electrode body, 2A ... First electrode body (partial electrode body), 2B ... Second electrode body (remaining electrode body), 2C ... Curved part, 2F ... Flat part, 20 ... Electrode, 201 ... Winding center side portion, 202 ... Outer peripheral side electrode, 21 ... Electrode body, 211 ... Conductive layer, 212 ... Active material layer, 22 ... Current collecting tab, 23 ... Positive electrode (electrode), 230 ... Positive electrode body (electrode body), 231 ... metal foil, 2311 ... foil body, 2311A ... outer surface of foil body, 2311B ... inner surface of foil body, 2312 ... positive electrode current collecting tab (current collecting tab), 232 ... positive electrode active material Layer, 24 ... Negative electrode (electrode), 240 ... Negative electrode body (electrode body), 241 ... Metal foil, 2411 ... Foil body, 2412 ... Negative electrode current collection tab (collection tab), 242 ... Negative electrode active material layer, 25 ... Separator 3, 3 ... Case, 31 ... Case body, 311 ... Closure part, 312 ... Body part, 313 ... Long wall part, 314 ... Short wall part, 32 ... Lid plate, 34 ... Opening peripheral part, 4 ... External terminal, 5 ... Collection Electrical body, 6 ... Insulating member, 11 ... Power storage device, 12 ... Bus bar member, 501 ... Winding center side part, 502 ... Outer peripheral side electrode, C ... Winding shaft, α ₀ ... Electrode outermost outermost part, α ₁ ... outermost part of the positive electrode, β ₀ ... innermost part of the electrode, β ₁ ... innermost part of the positive electrode, β ₂ ... innermost part of the negative electrode

Claims (5)

A band-shaped electrode body that is wound, and a plurality of electrode bodies that each have a piece-shaped current collecting tab that conducts with the electrode body.
A case is provided in which the plurality of electrode bodies are housed so that adjacent electrode bodies face each other so that the winding axes of the electrode bodies are oriented in the same direction and their peripheral surfaces are in contact with each other.
A power storage element in which some of the plurality of electrode bodies have different winding directions from the remaining electrode bodies. The power storage element according to claim 1, wherein the case accommodates the plurality of electrode bodies so that the winding directions of the electrode bodies of the adjacent electrode bodies are different from each other. The case accommodates at least one set of electrode bodies when two sets of electrode bodies arranged in different winding directions of the electrode body are used as a set of electrode bodies.
The claim that each electrode body is arranged so that the outermost peripheral end portion of the electrode body is located outside the alignment direction of the two electrode bodies in the electrode body set. The power storage element according to 1. The current collecting tab extends from the outermost peripheral end of the wound electrode body.
The power storage element according to any one of claims 1 to 3, wherein each of the current collecting tabs of the plurality of electrode bodies is bundled. The electrode body has a strip-shaped conductive layer and an active material layer to be superimposed on the conductive layer.
At the portion of the electrode body that constitutes the outermost circumference of the electrode body, the active material layer is not laminated on the surface facing the outside of the conductive layer.
The power storage element according to any one of claims 1 to 4, wherein adjacent electrode bodies in the plurality of electrode bodies are in contact with each other where the active material layers are not laminated.

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