JP6219775B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device having a structure that applies a binding force to a plurality of power storage elements.

  In the assembled battery described in Patent Document 1, a plurality of secondary batteries are arranged in a predetermined direction, and a spacer is disposed between two adjacent secondary batteries. In addition, a pair of end plates are arranged at both ends of the assembled battery in a predetermined direction, and a restraining band extending in a predetermined direction is fixed to the pair of end plates. When the assembled battery is assembled, the distance between the pair of end plates is fixed, and a predetermined binding force is applied to the secondary battery via the spacer.

  In Patent Document 1, a spacer is brought into contact with a part of the power generation region (region not including the central portion) included in the flat surface in the square case of the secondary battery. Here, the power generation region is a region that overlaps in a predetermined direction with the power generation area of the power generation element housed in the square case, out of the flat surface of the square case. The power generation area is an area where the positive electrode plate and the negative electrode plate overlap each other.

JP 2012-230837 A

  The power generation element expands or contracts according to charge / discharge. Further, the power generation element expands or contracts in response to the temperature of the power generation element changing. Such expansion and contraction of the power generation element occurs in the power generation area described in Patent Document 1. If the spacer is brought into contact with the power generation region of the square case as in Patent Document 1, the spacer is easily affected by the expansion and contraction of the power generation element.

  The restraining force generated using the end plate and the restraining band acts on the secondary battery via the spacer. Here, if the spacer is affected by the expansion and contraction of the power generation element, the binding force applied to the secondary battery via the spacer changes. As a result, a predetermined (constant) binding force cannot be continuously applied to the secondary battery.

  The power storage device of the present invention includes a plurality of power storage elements arranged in a predetermined direction, and a partition member disposed between two power storage elements adjacent in the predetermined direction. The power storage device has a pair of end plates and a plurality of connecting members. The pair of end plates are disposed at positions sandwiching the plurality of power storage elements in a predetermined direction, and are used to apply a binding force in a predetermined direction to the plurality of power storage elements. Each of the plurality of connecting members extends in a predetermined direction and is connected to the pair of end plates.

The power storage element includes a power generation element and a case that houses the power generation element and includes a flat surface that is orthogonal to a predetermined direction. The power generation element includes a positive electrode plate in which a positive electrode active material layer is formed in a part of the positive electrode current collector plate, and a negative electrode plate in which a negative electrode active material layer is formed in a part of the negative electrode current collector plate. It is comprised by laminating | stacking. The power generation element includes a first region facing the positive electrode active material layer and the negative electrode active material layer in a predetermined direction, a region other than the first region, and a second region in which the positive electrode active material layer is not formed in the positive electrode current collector plate. And a third region in which the negative electrode active material layer is not formed among the region and the negative electrode current collector plate. A partition member has a projection part which gives restraining force via a flat surface to each of the 2nd field and 3rd field which are separated from each other on both sides of the 1st field. The partition member applies a restraining force to the first region where the projecting portion is not provided by a tension acting on the second region and the third region to which the restraining force is applied by the projecting portion.

  In the power generation element, a region where the positive electrode active material layer and the negative electrode active material layer face each other with the separator interposed therebetween (referred to as a facing region) expands or contracts. Since the constraining force from the partition member is not applied to the facing region, it is possible to suppress the expansion and contraction of the facing region from acting on the partition member. Along with this, it is possible to suppress a change in the binding force applied from the partition member to the power storage element due to the expansion and contraction of the facing region. In other words, the restraining force applied from the partition member to the power storage element can be kept constant.

  Moreover, tension can be generated in the positive electrode current collector plate and the negative electrode current collector plate by applying a binding force to the positive electrode current collector plate and the negative electrode current collector plate. By using this tension, a load can be applied to the facing region. If the load applied to the facing area decreases, deterioration of the storage element (power generation element) (decrease in the full charge capacity) is likely to proceed, but by applying a load to the facing area as described above, Deterioration of the power storage element can be suppressed.

It is an external view of a battery stack. It is a figure which shows the internal structure of a cell. It is an expanded view of an electric power generation element. It is an external view of a power generation element. It is a front view of a partition member. It is sectional drawing of a cell and a partition member. It is a figure which shows the change of the capacity | capacitance maintenance rate of a cell. It is sectional drawing of a partition member. It is sectional drawing of a partition member. It is sectional drawing of a partition member. It is a figure explaining the path | route which supplies the air for temperature control to a cell. It is a figure explaining the path | route which supplies the air for temperature control to a cell.

  Examples of the present invention will be described below.

  The structure of the battery stack of this embodiment (corresponding to the power storage device of the present invention) will be described with reference to FIG. In FIG. 1, an X axis, a Y axis, and a Z axis are axes orthogonal to each other. In this embodiment, the axis corresponding to the vertical direction is the Z axis. The relationship among the X axis, the Y axis, and the Z axis is the same in other drawings.

  The battery stack 1 has a plurality of single cells (corresponding to the power storage elements of the present invention) 10, and the plurality of single cells 10 are arranged in the X direction (corresponding to a predetermined direction of the present invention). A positive electrode terminal 11 and a negative electrode terminal 12 are provided on the upper surface of the unit cell 10. The plurality of unit cells 10 are connected in series via a positive electrode terminal 11 and a negative electrode terminal 12. As the unit cell 10, a secondary battery such as a nickel metal hydride battery or a lithium ion battery can be used.

  A partition member 20 is disposed between two unit cells 10 adjacent in the X direction. The partition member 20 can be formed of an insulating material such as resin. As will be described later, a part of the partition member 20 is in contact with the unit cell 10. In a region where the unit cell 10 and the partition member 20 are not in contact with each other, a space is formed between the unit cell 10 and the partition member 20.

  A pair of end plates 31 are disposed at both ends of the battery stack 1 in the X direction. That is, the pair of end plates 31 sandwich all the unit cells 10 constituting the battery stack 1 in the X direction. The pair of end plates 31 are used to give a binding force to the plurality of single cells 10. By displacing the pair of end plates 31 in a direction approaching each other (X direction), a binding force can be applied to the plurality of single cells 10 sandwiched between the pair of end plates 31. This restraining force is a force that sandwiches each unit cell 10 in the X direction.

  Both ends of a connecting member 32 extending in the X direction are connected to the pair of end plates 31. The end plate 31 and the connecting member 32 can be connected using a fastening member such as a bolt or a rivet, or can be connected by a welding process or the like. As shown in FIG. 1, two connecting members 32 are arranged on each of the upper surface and the lower surface of the battery stack 1. The two connecting members 32 disposed on the upper surface of the battery stack 1 are disposed at positions that do not interfere with the positive electrode terminal 11 and the negative electrode terminal 12.

  By connecting the connecting member 32 to the pair of end plates 31, the pair of end plates 31 can be displaced in a direction (X direction) approaching each other. Thereby, as mentioned above, a binding force can be applied to the plurality of single cells 10. Since it is sufficient that a binding force can be applied to the plurality of single cells 10, in consideration of this point, the position where the coupling member 32 is disposed and the number of the coupling members 32 can be appropriately set.

  Next, the structure of the unit cell 10 will be described with reference to FIG.

  The unit cell 10 includes a battery case (corresponding to a case of the present invention) 13 and a power generation element 14 accommodated in the battery case 13. The battery case 13 is formed in a shape along a rectangular parallelepiped and has a case main body 13a and a lid 13b. The case main body 13a has an opening for incorporating the power generation element 14 into the case main body 13a, and the opening is closed by a lid 13b.

  By fixing the lid 13b to the case body 13a, the inside of the battery case 13 is hermetically sealed. The lid 13b constitutes the upper surface of the battery case 13 (unit cell 10). The positive electrode terminal 11 and the negative electrode terminal 12 are fixed to the lid 13b and penetrate the lid 13b.

  The power generation element 14 is an element that performs charging and discharging. A positive electrode tab 15 a and a negative electrode tab 15 b are connected to the power generation element 14. The positive electrode tab 15 a is also connected to the positive electrode terminal 11, and the negative electrode tab 15 b is connected to the negative electrode terminal 12. Thereby, the power generation element 14 can be charged / discharged by connecting the positive electrode terminal 11 and the negative electrode terminal 12 to a load. Here, the power generation element 14 is fixed to the lid 13b via the positive electrode tab 15a, the negative electrode tab 15b, the positive electrode terminal 11, and the negative electrode terminal 12. Therefore, the power generation element 14 is positioned inside the battery case 13.

  Next, the structure of the power generation element 14 will be described with reference to FIGS. 3 and 4. FIG. 3 is a developed view of a part of the power generation element 14, and FIG. 4 is an external view of the power generation element 14.

  The power generation element 14 includes a positive electrode plate 141, a negative electrode plate 142, and a separator 143. The positive electrode plate 141 includes a positive electrode current collector plate 141a and a positive electrode active material layer 141b formed on the surface (both surfaces) of the positive electrode current collector plate 141a. The positive electrode active material layer 141b includes a positive electrode active material, a conductive agent, a binder, and the like. The positive electrode active material layer 141b is formed in a partial region of the positive electrode current collector plate 141a, and the other region of the positive electrode current collector plate 141a is exposed. This exposed region is located at one end of the positive electrode current collector 141a in the Y direction.

  The negative electrode plate 142 includes a negative electrode current collector plate 142a and a negative electrode active material layer 142b formed on the surface (both surfaces) of the negative electrode current collector plate 142a. The negative electrode active material layer 142b includes a negative electrode active material, a conductive agent, a binder, and the like. The negative electrode active material layer 142b is formed in a partial region of the negative electrode current collector plate 142a, and the other region of the negative electrode current collector plate 142a is exposed. This exposed region is located at the other end of the negative electrode current collector 142a in the Y direction. The positive electrode active material layer 141b, the negative electrode active material layer 142b, and the separator 143 are infused with an electrolytic solution.

  The positive electrode plate 141, the negative electrode plate 142, and the separator 143 are stacked in the order shown in FIG. 3, and the laminate is wound in the direction indicated by the arrow R in FIG. 14 is configured. As shown in FIG. 4, the power generation element 14 has three regions A1, A2, and A3.

  The region A1 is a region where the positive electrode active material layer 141b and the negative electrode active material layer 142b face each other with the separator 143 interposed therebetween, and is a region where a chemical reaction corresponding to charge / discharge of the power generation element 14 is performed. In the region A1, the reaction-related substance moves between the positive electrode active material layer 141b and the negative electrode active material layer 142b in accordance with charging / discharging of the power generation element 14. Along with this, the region A1 expands or contracts. The reaction participating substance is a substance that participates in charging / discharging of the power generation element 14. For example, when a lithium ion secondary battery is used as the single battery 10, the reaction participating substance is lithium ion. On the other hand, the region A1 expands and contracts also when the temperature of the power generation element 14 changes.

  The region A2 is located at one end of the power generation element 14 in the Y direction, and only the positive electrode current collector 141a is wound in the region A2. As described with reference to FIG. 2, the positive electrode tab 15a is connected to the positive electrode current collector plate 141a in the region A2. In the region A2, the positive electrode current collectors 141a stacked on each other are fixed by a welding process.

  The region A3 is located at the other end of the power generation element 14 in the Y direction, and only the negative electrode current collector plate 142a is wound in the region A3. As described with reference to FIG. 2, the negative electrode tab 15b is connected to the negative electrode current collector plate 142a in the region A3. Further, in the region A3, the negative electrode current collector plates 142a overlapped with each other are fixed by a welding process.

  Note that, depending on the structure of the power generation element 14, the positive electrode active material layer 141b includes a region facing the negative electrode active material layer 142b (referred to as a facing region) and a region not facing the negative electrode active material layer 142b (referred to as a non-facing region). May have. Alternatively, the negative electrode active material layer 142b may have a region facing the positive electrode active material layer 141b (referred to as a facing region) and a region not facing the positive electrode active material layer 141b (referred to as a non-facing region). In this case, the regions A2 and A3 include the non-opposing regions described above. Further, the above-described facing area is the area A1.

  Next, the structure of the partition member 20 will be described with reference to FIG. FIG. 5 is a front view of the partition member 20 viewed from the X direction.

  The partition member 20 has a main body portion 21 and a projection portion 22. The main body portion 21 is disposed in the YZ plane and faces the battery case 13 (case main body 13a) in the X direction. The protruding portion 22 protrudes from the main body portion 21 in the X direction. And the front-end | tip of the projection part 22 contacts the battery case 13 (case main body 13a).

  The protrusion 22 has two regions P11 and P12 extending in the Z direction and two regions P13 and P14 extending in the Y direction in the YZ plane. Here, both ends of the region P11 in the Z direction are connected to the two regions P13 and P14, and both ends of the region P12 in the Z direction are connected to the two regions P13 and P14. In the regions P11 to P14, the height (the length in the X direction) of the protrusion 22 is equal.

  FIG. 6 is a cross-sectional view of the two partition members 20 and the unit cell 10 taken along the XY plane. As shown in FIG. 6, in each partition member 20, protrusions 22 are provided on both end surfaces of the main body 21 in the X direction.

  In addition, the protrusion part 22 can be provided in at least one among the both end surfaces of the main-body part 21 in a X direction. Here, the end surface of the main body portion 21 where the protruding portion 22 is not provided can be configured as a flat surface. The flat surface can be brought into contact with the battery case 13.

  The protrusion 22 faces each region A2, A3 of the power generation element 14 in the X direction via the side surface 13A of the battery case 13 (case body 13a). Specifically, the region P11 of the protrusion 22 faces the region A2 of the power generation element 14 in the X direction via the side surface 13A. Further, the region P12 of the protrusion 22 is opposed to the region A3 of the power generation element 14 via the side surface 13A.

  Here, the side surface 13A is a part of the battery case 13 (case body 13a), and forms a flat surface along the YZ plane. The battery case 13 has a pair of side surfaces 13A, and the pair of side surfaces 13A are located on both ends of the power generation element 14 in the X direction.

  The region P11 may be opposed to at least a part of the region A2 without facing the region A1 in the X direction. As long as this condition is satisfied, the length of the region P11 in the Y direction can be set as appropriate. Further, the region P12 may be opposed to at least a part of the region A3 without facing the region A1 in the X direction. As long as this condition is satisfied, the length of the region P12 in the Y direction can be set as appropriate.

  The regions P13 and P14 of the protrusion 22 are provided at positions that do not face the region A1 in the X direction. In this embodiment, the protrusion 22 has the regions P13 and P14, but the regions P13 and P14 may be omitted. That is, the two protrusions 22 can be provided at the positions where the regions P11 and P12 shown in FIG. 5 are provided. However, as in the present embodiment, by using the protrusions 22 configured by the regions P11 to P14, the unit cell 10 in contact with the protrusions 22 can be easily positioned in the YZ plane. Thereby, it becomes easy to apply the restraining force in the X direction to the unit cell 10 via the partition member 20.

  As described above, the region A1 expands and contracts, but the partition member 20 is not in contact with the region of the side surface 13A that faces the region A1 in the X direction. For this reason, it can control that expansion and contraction of field A1 act on partition member 20. Accordingly, even when a restraining force in the X direction is applied to the single cell 10 via the partition member 20, it is possible to suppress the restraining force applied to the single cell 10 from changing due to expansion and contraction of the region A1. Here, in the space formed between the main body portion 21 of the partition member 20 and the side surface 13A of the battery case 13, the expansion and contraction of the region A1 can be allowed.

  When the protrusion 22 is provided only on one end surface of the main body 21 in the X direction, the other end surface (flat surface) of the main body 21 where the protrusion 22 is not provided contacts the side surface 13A. At this time, the expansion and contraction of the region A1 acts on the other end surface of the main body 22, but the expansion and contraction of the region A1 can be allowed on the side where the protrusion 22 is in contact. Thereby, it can suppress that the restraint force given to the cell 10 changes by expansion | swelling and shrinkage | contraction of area | region A1.

  On the other hand, the binding force generated using the end plate 31 and the connecting member 32 is applied to the single battery 10 (battery case 13) via the partition member 20. For this reason, even if gas is generated inside the battery case 13 and the pressure inside the battery case 13 rises, the battery accompanying the rise in pressure can be obtained by using the binding force applied from the partition member 20 to the battery case 13. Expansion of the case 13 can be suppressed. Thereby, the binding force can be continuously applied from the partition member 20 to the battery case 13.

  Further, when the X-direction restraining force is generated using the end plate 31 and the connecting member 32, the region P <b> 11 of the protrusion 22 presses the region A <b> 2 of the power generation element 14 through the side surface 13 </ b> A of the battery case 13. Here, since the region A2 is located between the two protrusions 22 (region P11), a load that sandwiches the region A2 in the X direction is generated.

  Further, when the X-direction restraining force is generated using the end plate 31 and the connecting member 32, the region P <b> 12 of the protrusion 22 presses the region A <b> 3 of the power generation element 14 through the side surface 13 </ b> A of the battery case 13. Here, since the region A3 is located between the two protrusions 22 (region P12), a load that sandwiches the region A3 in the X direction is generated.

  By generating a load that sandwiches the regions A2 and A3 in this way, tension acting in the direction indicated by the arrow D1 in FIG. 6 can be generated on the positive electrode current collector 141a disposed in the region A2. Moreover, the tension | tensile_strength which acts on the direction shown by arrow D2 of FIG. 6 can be generated in the negative electrode current collection plate 142a arrange | positioned in area | region A3.

  By generating tension indicated by arrows D1 and D2 on the positive electrode current collector 141a and the negative electrode current collector 142a, a load in the X direction can be applied to the region A1. That is, the load in the X direction can be applied to the region A1 by pulling the positive electrode current collector 141a and the negative electrode current collector 142a in the directions of arrows D1 and D2. This load is a load that sandwiches the region A1 in the X direction. By giving such a load to area | region A1, the fall of the full charge capacity of the electric power generation element 14 (namely, deterioration of the cell 10) was able to be suppressed.

  FIG. 7 shows a change in the capacity maintenance rate of the unit cell 10 (power generation element 14) when the unit cell 10 is repeatedly charged and discharged with a predetermined current pattern. In FIG. 7, the vertical axis represents the capacity maintenance rate, and the horizontal axis represents the number of cycles.

  The capacity maintenance rate is a value obtained by dividing the full charge capacity of the single cell 10 after charging and discharging by the full charge capacity of the single cell 10 in the initial state. The initial state is a state in which the unit cell 10 is not deteriorated, for example, a state immediately after the unit cell 10 is manufactured. If the full charge capacity of the unit cell 10 is not lowered from the full charge capacity in the initial state, the capacity maintenance rate is “1”. The number of cycles is the number of cycles when charging / discharging with a predetermined current pattern is one cycle.

  In FIG. 7, the solid line indicates the change in capacity retention rate in the present example, and the alternate long and short dash line indicates the change in capacity retention rate in the comparative example. In the comparative example, the load that sandwiches the power generation element 14 in the X direction is not applied to the power generation element 14. As can be seen from FIG. 7, in this example, it is possible to suppress a decrease in capacity retention rate compared to the comparative example. In particular, as the number of cycles increases, it becomes easier to suppress a decrease in capacity maintenance rate.

  The shape of the protrusion 22 in the XY plane is not limited to the shape shown in FIG. For example, the shape shown in FIGS. 8 to 10 can also be used as the shape of the protrusion 22 in the XY plane. 8 to 10 correspond to FIG.

  In the partition member 20 shown in FIG. 8, the protrusion 22 has an inclined surface 22a. The inclined surface 22a is formed in each of the regions P11 and P12 of the protrusion 22. Here, when the protruding portion 22 shown in FIG. 6 is used, the positive electrode current collector 141a and the negative electrode current collector plate located inside the power generation element 14 increase as the length (thickness) of the power generation element 14 in the X direction increases. It becomes difficult to apply a load to 142a.

  As can be seen from FIG. 6, in the region A2, the length (thickness) of the power generation element 14 in the X direction continuously changes. Also. Also in the region A3, the length (thickness) of the power generation element 14 in the X direction continuously changes. If the protrusion 22 is provided with the inclined surface 22a, the outer shape of the protrusion 22 (inclined surface 22a) can be made to follow the outer shape of the power generation element 14 in each of the regions A2 and A3. Accordingly, it is possible to easily apply a load to the entire positive electrode current collector plate 141a located in the region A2, or to easily apply a load to the entire negative electrode current collector plate 142a located in the region A3.

  In the partition member 20 shown in FIG. 9, the protrusion 22 has two inclined surfaces 22a and 22b. The two inclined surfaces 22a and 22b are formed in the respective regions P11 and P12 of the protrusion 22. In FIG. 9, the length of the protrusion 22 in the Y direction is shorter toward the tip of the protrusion 22.

  Thereby, in the protrusion part 22 shown in FIG. 9, the area which contacts the side surface 13A of the battery case 13 becomes small compared with the protrusion part 22 shown in FIG. Here, if the restraining forces generated by the end plate 31 and the connecting member 32 are equal, the load applied to the battery case 13 (in other words, the regions A2 and A3 of the power generation element 14) from the protrusion 22 shown in FIG. 6 is larger than the load applied to the battery case 13 (in other words, the regions A2 and A3 of the power generation element 14) from the protrusion 22 shown in FIG. Therefore, in the partition member 20 illustrated in FIG. 9, it is easier to apply a load to the regions A <b> 2 and A <b> 3 of the power generation element 14 than in the partition member 20 illustrated in FIG. 6.

  In the partition member 20 shown in FIG. 10, the tip of the protrusion 22 is formed by a curved surface 22c. The curved surface 22c has a curvature in the XY plane and protrudes toward the side surface 13A of the battery case 13. Here, since the apex of the curved surface 22c comes into contact with the side surface 13A of the battery case 13, a larger load than the protrusion 22 shown in FIG. 9 is applied to the battery case 13 (in other words, the regions A2, A3 of the power generation element 14). ) Can be given. Along with this, it becomes easier to apply a load to each of the regions A2 and A3 of the power generation element 14.

  Next, in the battery stack 1 of the present embodiment, a configuration for supplying air for adjusting the temperature of the unit cell 10 to the unit cell 10 will be described with reference to FIGS. 11 and 12. By bringing the temperature adjusting air into contact with the battery case 13, heat exchange can be performed between the air and the cell 10, and the temperature of the cell 10 can be adjusted.

  In FIG. 11 and FIG. 12, the direction in which the temperature adjusting air moves is indicated by arrows. Here, if a space is formed along the air movement path, the air can be moved as shown in FIGS. The air moving path can be configured by the unit cell 10 (battery case 13) and members disposed around the unit cell 10. As a member arrange | positioned around the cell 10, the partition member 20 can be used, for example.

  In FIG. 11, after the temperature adjusting air contacts the bottom surface 13 </ b> B of the battery case 13, the air moves along the bottom surface 13 </ b> B. The moving direction of the air at this time is the Y direction. Here, the upper surface and the bottom surface 13B of the battery case 13 are disposed on both ends of the power generation element 14 in the Z direction. As described above, the positive electrode terminal 11 and the negative electrode terminal 12 are provided on the upper surface of the battery case 13.

  When air reaches both ends of the bottom surface 13B in the Y direction, the air moves along the side surfaces 13C of the battery case 13. At this time, the moving direction of the air is the Z direction. The battery case 13 has a pair of side surfaces 13C, and the pair of side surfaces 13C are located on both ends of the power generation element 14 in the Y direction. The air that has passed through the side surface 13C can be guided to a predetermined position using, for example, a duct (not shown).

  In FIG. 12, after the temperature adjusting air contacts the bottom surface 13B of the battery case 13, the air moves along the bottom surface 13B. The moving direction of the air at this time is the X direction. When air reaches both ends of the bottom surface 13B in the X direction, the air moves along each side surface 13A of the battery case 13. At this time, the moving direction of the air is the Z direction.

  If a guide is provided in the main body portion 21 of the partition member 20, the air guided to the side surface 13A of the battery case 13 can be easily moved along the guide. Here, the guide is not in contact with the side surface 13A. If the guide is brought into contact with the side surface 13A, the expansion and contraction of the region A1 of the power generation element 14 may act on the partition member 20, so the guide needs to be separated from the side surface 13A.

  In the configuration shown in FIG. 12, the air guided from the bottom surface 13B to the side surface 13A moves in the Z direction and then moves toward the side surface 13C. Thereby, the temperature-adjusted air can be discharged into a space formed along the side surface 13C. When the air is moved toward the side surface 13C, a space through which air passes may be formed in each of the regions P11 and P12 of the protrusion 22 shown in FIG.

1: battery stack, 10: single cell, 11: positive electrode terminal, 12: negative electrode terminal,
13: battery case, 14: power generation element, 141: positive electrode plate, 141a: positive electrode current collector plate,
141b: positive electrode active material layer, 142: negative electrode plate, 142a: negative electrode current collector plate,
142b: negative electrode active material layer, 143: separator, 20: partition member, 21: body part,
22: Projection, 31: End plate, 32: Connecting member

Claims (4)

A plurality of power storage elements arranged in a predetermined direction;
A partition member disposed between the two power storage elements adjacent in the predetermined direction;
A pair of end plates disposed at positions sandwiching the plurality of power storage elements in the predetermined direction, and for applying a binding force in the predetermined direction to the plurality of power storage elements;
A plurality of connecting members extending in the predetermined direction and respectively connected to the pair of end plates;
The power storage element is
A positive electrode plate in which a positive electrode active material layer is formed in a part of the positive electrode current collector plate and a negative electrode plate in which a negative electrode active material layer is formed in a part of the negative electrode current collector plate are stacked via a separator. A power generation element constituted by
A case containing the power generation element and having a flat surface perpendicular to the predetermined direction,
The power generation element includes a first region facing the positive electrode active material layer and the negative electrode active material layer in the predetermined direction, a region other than the first region, and the positive electrode active material layer of the positive electrode current collector plate. A second region in which the negative electrode current collector plate is not formed, and a second region in which the negative electrode active material layer is not formed.
It said partition member, relative to each of the second region and the third region are separated from each other across the first region, have a protrusion providing said restraining force through the flat surface,
The partition member applies the restraining force to the first region where the protrusion is not provided by the tension acting on the second region and the third region to which the restraining force is applied by the protrusion. power storage apparatus characterized by causing. The partition member forms a space that allows deformation of the first region with expansion of the power generation element by the protrusions contacting the flat surfaces corresponding to the second region and the third region. The power storage device according to claim 1. The tip of the protrusion that contacts the flat surface is formed so that at least a part thereof is inclined with respect to the flat surface, or is formed in a shape that protrudes in a curved shape toward the flat surface. The power storage device according to claim 1, wherein the power storage device is a power storage device. The protrusion is disposed so as to surround the first region where the protrusion is not provided, with respect to the flat surface of at least one of the two power storage elements adjacent in the predetermined direction. The power storage device according to any one of claims 1 to 3.

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