JP2018029014A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of achieving lighter weight while securing rigidity.SOLUTION: A power storage device 10 comprises an outer package 12, a power storage element group 22 in which a plurality of power storage elements 24 are arranged a long a lamination direction of electrode sheets 36 and 37, and a reinforcing member 46 arranged between an external surface of the outer package 12 and the power storage element group 22. The reinforcing member 46 comprises a first reinforcing material 48 arranged in an end of the power storage element 24 in an arrangement direction, and second reinforcing members 54A and 54B arranged in the end of the power storage element 24 in a direction crossing the arrangement direction. A yield stress of a first material forming the first reinforcing member 48 is stronger than a yield stress of a second material forming the second reinforcing members 54A and 54B. A specific gravity of the first material is heavier than a specific gravity of the second material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device.

  A power storage device in which a plurality of power storage elements are arranged inside an exterior body is known. In the power storage device of Patent Document 1, a reinforcing member is disposed so as to surround the outer periphery of a power storage element group including a plurality of power storage elements. By this reinforcing member, deformation of the exterior body due to expansion of the power storage element and prevention of deformation of the power storage element due to an external force during a vehicle collision or the like are intended.

JP 2006-91871 A

  However, since the power storage device of Patent Document 1 uses a reinforcing member having high strength in order to counter the force from the inside and outside, deformation of the power storage element can be prevented, but the overall weight increases.

  An object of the present invention is to provide a power storage device that can be reduced in weight while ensuring rigidity.

  The power storage device of the present invention includes an exterior body, a power storage element group arranged in the exterior body, and a plurality of electrical storage elements having stacked electrode sheets arranged in the stacking direction of the electrode sheets, and the exterior body And a reinforcing member disposed between the outer surface of the battery and the power storage element group. The reinforcing member is disposed at an end portion in the arrangement direction of the electricity storage elements, and is disposed at an end portion in a direction intersecting the arrangement direction of the electricity storage elements, with a first reinforcing material made of a first material. And a second reinforcing material made of a second material different from the above material. The yield stress of the first material is stronger than the yield stress of the second material, and the specific gravity of the first material is heavier than the specific gravity of the second material.

  Since the first reinforcing member is made of the first material having a higher yield stress and a higher specific gravity than the second material forming the second reinforcing member, the first reinforcing member has a higher mechanical strength than the second reinforcing member. 2 Weight per unit volume is heavier than reinforcement. Conversely, the second reinforcing material has a lower mechanical strength than the first reinforcing material, but is lighter in weight per unit volume than the first reinforcing material. And according to this electrical storage apparatus, a some electrical storage element is arranged along the lamination direction of an electrode sheet, and the 1st reinforcement material is arrange | positioned at the edge part of the arrangement direction. Therefore, since the expansion | swelling of the lamination direction of the electrode sheet in an electrical storage element can be suppressed with a 1st reinforcing material, a deformation | transformation of an exterior body can be prevented reliably. Moreover, even if the external force toward the edge part of the electrode sheet in an electrical storage element applies to an exterior body, it can suppress that an exterior body deform | transforms with a 1st reinforcement material. Therefore, the short circuit by the end part of an electrode sheet deform | transforming can be prevented reliably. On the other hand, a second reinforcing material is disposed at an end portion in a direction crossing the arrangement direction of the power storage elements. Therefore, in this power storage device, the first reinforcing member and the second reinforcing member can reduce the weight while ensuring a predetermined rigidity.

  The power storage element includes a pair of first side surface portions that are spaced apart from each other, and a pair of second side surface portions that extend in a direction intersecting the first side surface portions and have a total length shorter than the total length of the first side surface portions. A case is provided. The electrode sheet is laminated from one to the other of the pair of first side surface portions. In the electricity storage device of this aspect, the compressive strength in the short direction is strong, but the compressive strength in the longitudinal direction is weak and easily swells in the short direction, but hardly swells in the longitudinal direction. Therefore, a predetermined rigidity can be ensured by arranging the first reinforcing member at the end of the storage element in the arrangement direction.

  The first reinforcing material is disposed at both ends of the storage element in the arrangement direction. According to this aspect, deformation and expansion of the power storage element can be reliably prevented.

  The second reinforcing material is disposed at both ends in a direction intersecting the arrangement direction of the power storage elements. According to this aspect, the entire power storage device can be reliably reduced in weight.

  The first reinforcing material and the second reinforcing material are connected via a third material that is different from both the first material and the second material. In this case, it is preferable that the third material has an ionization tendency that is an intermediate material between the first material and the second material. According to this aspect, it is possible to reliably prevent corrosion of the connecting portion between the first reinforcing material and the second reinforcing material.

  At least a connecting portion between the first reinforcing material and the second reinforcing material is covered with resin. According to this aspect, since the connection part of a 1st reinforcement material and a 2nd reinforcement material is not exposed to air, corrosion of a connection part can be prevented reliably.

  The exterior body has a rectangular shape including a pair of first surfaces located at both ends in the arrangement direction of the power storage elements and a pair of second surfaces located at both ends in a direction intersecting the arrangement direction of the power storage elements. The first reinforcing member is located at a corner where the first surface and the second surface intersect. According to this aspect, since the first reinforcing material is located at the corner of the exterior body, the rigidity of the exterior body can be improved.

  The first reinforcing member includes a main body extending along the first surface and bent portions bent at both ends of the main body so as to extend along the second surface. According to this aspect, the rigidity of the corner portion of the exterior body can be reliably improved.

  The total length of the first reinforcing material is shorter than the total length of the second reinforcing material. According to this aspect, the portion having a short total length and a small volume is the first reinforcing material made of the first material, and the portion having a long full length and the large volume is the second reinforcing material made of the second material. The power storage device can be reliably reduced in weight.

  In the power storage device of the present invention, the first reinforcing material having a high yield stress and a high specific gravity is arranged at the end in the arrangement direction of the storage elements, and the yield stress is weak at the end in the direction intersecting the arrangement direction of the storage elements. Since the second reinforcing material having a low specific gravity is disposed, it is possible to reduce the weight while ensuring the rigidity.

1 is a cross-sectional view illustrating a schematic configuration of a power storage device according to a first embodiment. II-II sectional view taken on the line of FIG. The perspective view which shows the electrical storage element and reinforcing member of FIG. The exploded perspective view of an electrical storage element. The exploded perspective view of a reinforcement member. The cross-sectional view which shows schematic structure of the electrical storage apparatus of 2nd Embodiment. The cross-sectional view which shows schematic structure of the electrical storage apparatus of 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 and 2 show a power storage device 10 according to the first embodiment. As shown in these drawings, the power storage device 10 includes an exterior body 12 and a battery module 22 housed inside the exterior body 12. In the present embodiment, the battery module 22 is prevented from being deformed by disposing the reinforcing member 46 between the outer surface of the exterior body 12 and the battery module 22.

(Entire configuration of power storage device)
As shown in FIGS. 1 and 2, the exterior body 12 includes a resin case main body 13 having an opening on one surface (upper surface), and a lid body 17 that closes the opening of the case main body 13. The case body 13 is a rectangular box whose dimension in the X direction in FIG. 1 is shorter than the dimension in the Z direction, and includes a substantially rectangular bottom wall portion 14. On the bottom wall portion 14, a long side wall portion 15 is erected on a pair of long sides, and a short side wall portion 16 is erected on a pair of short sides. Among them, the short side wall portions 16 and 16 are a pair of first surfaces located at both ends in the arrangement direction of battery cells 24 to be described later. The long side wall portions 15, 15 are a pair of second surfaces that extend in a direction intersecting with the short side wall portions 16, 16 and are located at both ends in a direction intersecting with the arrangement direction of the battery cells 24. Referring to FIG. 2, the lid body 17 is fixed to the opening of the case body 13 in a liquid-tight and air-tight manner. The lid body 17 is provided with a positive external terminal 18 on one end side in the Z direction, which is the longitudinal direction of the exterior body 12, and a negative external terminal 19 on the other end side in the Z direction.

  As shown in FIGS. 1 to 3, the battery module 22 is a power storage element group in which a plurality of (for example, eight) battery cells 24 are arranged in the longitudinal direction (Z direction) of the exterior body 12 via spacers 23. . The battery cell 24 as a power storage element is a nonaqueous electrolyte secondary battery such as a lithium ion battery. However, in addition to the lithium ion battery, various battery cells 24 including a capacitor can also be applied. The lid 31 of the battery cell 24 is provided with a positive electrode terminal 32 at one end in the X direction which is the longitudinal direction of the battery cell 24 and a negative electrode terminal 33 at the other end in the X direction.

  A bus bar unit (not shown) and a circuit board unit (not shown) are further arranged in the exterior body 12. In the case of parallel connection, the bus bar unit electrically connects the positive terminals 32 of the determined battery cells 24 and electrically connects the negative terminals 33 of the determined battery cells 24. In the case of series connection, the bus bar unit electrically connects the positive terminal 32 of the determined battery cell 24 and the negative terminal 33 of the determined battery cell 24. The circuit board unit is connected to the bus bar unit and the external terminals 18, 19, electrically connects the plurality of positive terminals 32 to the positive external terminal 18, and electrically connects the plurality of negative terminals 33 to the negative external terminal 19. Connecting. As a result, each battery cell 24 can be charged and discharged through the positive external terminal 18 and the negative external terminal 19.

  As shown in FIG. 4, each battery cell 24 includes a case 26, an electrode body 35, and a pair of current collectors 42A and 42B.

  The case 26 includes a flat box-shaped case main body 27 having an opening on one surface (upper surface), and a lid 31 that closes the opening of the case main body 27. The case body 27 includes a bottom surface portion 28 having a substantially rectangular shape. A long side surface portion 29 is erected on a pair of long sides, and a short side surface portion 30 is erected on a pair of short sides. The long side surfaces 29 and 29 are a pair of first side surfaces positioned in parallel with a space therebetween. The short side surface portions 30, 30 extend in a direction intersecting the long side surface portions 29, 29, and a pair of second side lengths in the Z direction (horizontal width) are shorter than the total length (depth) in the X direction of the long side surface portions 29, 29. It is a side part. The lid 31 has a rectangular shape having the same size as the bottom surface portion 28 and is welded to the opening edge of the case main body 27. The lid 31 is provided with a positive terminal 32 at one end in the X direction and a negative terminal 33 at the other end in the X direction.

  The electrode body 35 includes a strip-shaped positive electrode body 36, a strip-shaped negative electrode body 37, and two strip-shaped separators 38, 38, and a flat winding wound around the winding axis Wa in a state where these are laminated. Is the body. The positive electrode body 36 and the negative electrode body 37 are electrically insulated by disposing a separator 38 therebetween. The end of the electrode body 35 has an oval shape, curved portions 39 and 39 are formed at both ends in the Y direction, and a flat portion 40 extending in the XY plane is formed between the curved portions 39 and 39. Yes. The electrode body 35 is disposed in the case 26 in such a posture that the winding axis Wa is along the longitudinal direction (X direction) of the case 26. Thereby, the sheet-like positive electrode body 36 and the negative electrode body 37 constituting the flat portion 40 are stacked in the Z direction from one long side surface portion 29 to the other long side surface portion 29.

  The current collectors 42 </ b> A and 42 </ b> B are generally L-shaped and include a first joint 43 and a second joint 44. The positive electrode current collector 42A is made of a metal such as aluminum, and the negative electrode current collector 42B is made of a metal such as copper. The 1st junction part 43 is arrange | positioned between the cover body 31 and the electrode body 35, and is joined to the terminals 32 and 33 of the cover body 31 by caulking, for example. The 2nd junction part 44 is arrange | positioned between the short side part 30 of the case main body 27, and the electrode body 35, and is joined to the edge part of the electrode body 35 by ultrasonic welding, for example. Thus, the current collectors 42A and 42B are electrically connected to the electrode body 35 and the terminals 32 and 33 of the case 26, respectively.

  The rigidity of the battery cell 24 is greatly related to the stacking direction of the positive electrode body 36 and the negative electrode body 37 as an electrode sheet. That is, the compressive strength in the Z direction, which is the laminating direction and the short direction, of the flat portion 40 is strong, but the compressive strength in the X direction, which is the extending direction of the flat portion 40 and the longitudinal direction, is weak. Conversely, the battery cell 24 is easy to swell in the Z direction, but is difficult to swell in the X direction. Therefore, it is strong against the force in the direction in which the pair of long side surface portions 29, 29 approaches, but is weak in the force in the direction in which the pair of short side surface portions 30, 30 approaches. Such a force corresponds to an external force applied to the exterior body 12. On the contrary, it is weak against the force in the direction in which the pair of long side portions 29, 29 are separated, but is strong in the force in the direction in which the pair of short side portions 30, 30 are separated. Such a force corresponds to an internal force that deforms (expands) the battery cell 24 when an unintended abnormality occurs in the electrode body 35.

  Referring to FIG. 1, the battery module 22 is configured by arranging a plurality of battery cells 24 along a stacking direction of a positive electrode body 36 shown by a thin line in FIG. 1 and a negative electrode body 37 shown by a broken line in FIG. 1. Therefore, the exterior body 12 that houses the battery module 22 is strong against the external force in the Z direction and weak against the external force in the X direction. The exterior body 12 is weak against the internal force in the Z direction and strong against the internal force in the X direction. Therefore, in the present embodiment, the reinforcing member 46 that can counter the external force in the X direction and the internal force in the Z direction is disposed between the exterior body 12 and the battery module 22.

(Details of reinforcement members)
As shown in FIGS. 1 to 3, the reinforcing member 46 is a frame that surrounds the outer periphery of the battery module 22, and includes a first reinforcing material 48 and two types of second reinforcing materials 54 </ b> A and 54 </ b> B. The first reinforcing members 48 are disposed at both ends in the arrangement direction (Z direction) of the battery cells 24. The second reinforcing members 54 </ b> A are disposed at both ends in the X direction (lateral direction) intersecting the arrangement direction of the battery cells 24. The second reinforcing members 54B are disposed at both ends in the Y direction (vertical direction) intersecting the arrangement direction of the battery cells 24. The first reinforcing material 48 and the second reinforcing materials 54A and 54B are formed of different materials. The second reinforcing material 54A and the second reinforcing material 54B are formed of the same material.

  Referring also to FIG. 5, the first reinforcing member 48 is a plate-shaped member that is made of a first metal material and has an area that substantially covers the long side surface portion 29 of the battery cell 24. The first reinforcing member 48 includes a main body 49, a first bent portion 50 for fixing the second reinforcing member 54A, and a second bent portion 51 for fixing the second reinforcing member 54B.

  The main body 49 is disposed between the inner surface of the short side wall portion 16 in the exterior body 12 and the battery module 22. Referring to FIG. 1, both ends of the main body 49 in the X direction are located at corners where the short side wall portion 16 and the long side wall portion 15 intersect. Referring to FIG. 2, one end of the main body 49 in the Y direction is located at a corner where the long side wall portion 15 and the bottom wall portion 14 intersect, and the other end of the main body 49 in the Y direction is the long side wall portion 15 and the lid. It is located at the corner where 17 intersects.

  2 and 5, the first bent portion 50 is bent at both ends of the main body 49 in the X direction so as to extend along the long side wall portion 15. The second bent portion 51 is bent at both ends in the Y direction of the main body 49 so as to extend along the bottom wall portion 14 or the lid body 17. A reinforcing rib 52 is provided between the main body 49 and the bent portions 50 and 51 by punching.

  The second reinforcing member 54 </ b> A is a belt-like member that extends in the Z direction across the plurality of battery cells 24 at both ends in the X direction of the battery module 22. The second reinforcing material 54 </ b> A is disposed between the inner surface of the long side wall portion 15 in the exterior body 12 and the battery module 22. At both ends of the second reinforcing member 54 </ b> A, through holes 55 for connecting to the first bent portion 50 of the first reinforcing member 48 are provided. One of the second reinforcing members 54 </ b> A and 54 </ b> A on both sides is connected on the lower side in the Y direction of the first reinforcing member 48, and the other is connected on the upper side in the Y direction of the first reinforcing member 48.

  The second reinforcing material 54 </ b> B is a belt-like member that extends in the Z direction across the plurality of battery cells 24 at both ends in the Y direction of the battery module 22. The lower second reinforcing material 54B is disposed between the inner surface of the bottom wall portion 14 and the battery module 22 in the exterior body 12, and the upper second reinforcing material 54B is formed between the inner surface of the lid 17 and the battery module 22. It is arranged between. At both ends of the second reinforcing material 54B, a pair of through holes 56, 56 for connecting to the second bent portion 51 of the first reinforcing material 48 are provided. Both the upper and lower second reinforcing members 54B and 54B are arranged at the center in the X direction.

  The second reinforcing members 54 </ b> A and 54 </ b> B are formed of a second metal material different from the first reinforcing member 48. As the second metal material, a material having a lower yield stress and a lower specific gravity than that of the first metal material is used. That is, the first metal material is a material having a higher yield stress and a higher specific gravity than the second metal material. As such a material, for example, iron can be used as the first metal material, and aluminum can be used as the second metal material. The first reinforcing member 48 thus configured has higher mechanical strength than the second reinforcing members 54A and 54B, and has a heavier weight per unit volume than the second reinforcing members 54A and 54B. On the other hand, the second reinforcing members 54 </ b> A and 54 </ b> B have lower mechanical strength than the first reinforcing member 48, but are lighter in weight per unit volume than the first reinforcing member 48. In this way, both the mechanical strength is secured and the weight is reduced.

  Note that the total length of the second reinforcing material 54A in the Z direction is longer than the total length of the first reinforcing material 48 in the X direction. On the other hand, the second reinforcing member 54 </ b> A is narrower in the Y direction than the first reinforcing member 48. The volume of the second reinforcing material 54 </ b> A is smaller than that of the first reinforcing material 48. The total length in the Z direction of the second reinforcing material 54B is longer than the total length of the first reinforcing material 48 in the X direction. On the other hand, the width of the second reinforcing material 54B in the X direction is narrower than the width of the first reinforcing material 48 in the Y direction. The volume of the second reinforcing material 54B is smaller than that of the first reinforcing material 48. Moreover, the second reinforcing member 54B of the present embodiment further reduces the volume by forming the punched holes 57 by punching.

  As shown in FIG. 5, the first reinforcing member 48 and the second reinforcing members 54 </ b> A and 54 </ b> B are connected by a screw shaft 59 fixed to the bent portions 50 and 51 and a nut 60. For example, as shown in FIG. 3, first reinforcing members 48, 48 are disposed at both ends of the battery cell 24 in the arrangement direction, second reinforcing members 54 </ b> A, 54 </ b> B are disposed at both sides of the battery cell 24, and the through holes 55 are provided. The screw shaft 59 is passed through. Then, the nut 60 is fastened to the screw shaft 59 to connect the first reinforcing member 48 and the second reinforcing member 54A so as not to move. Further, the second reinforcing material 54B is disposed above and below the battery cell 24, the screw shaft 59 is passed through the through hole 56, and the nut 60 is tightened, so that the first reinforcing material 48 and the second reinforcing material 54B cannot move. Connect as possible.

  The screw shaft 59 and the nut 60 are made of a third metal material different from any of the first and second metal materials. As the third metal material, an intermediate material having an ionization tendency between the first metal material and the second metal material is used. As such a material, when the first metal material is iron and the second metal material is aluminum, for example, zinc can be used. If it does in this way, corrosion of the connection part of the 1st reinforcement material 48 and the 2nd reinforcement materials 54A and 54B can be prevented.

  As shown in FIGS. 1 and 2, the power storage device 10 is assembled by housing the battery module 22 in which the reinforcing member 46 is disposed in the exterior body 12. In the power storage device 10, a plurality of battery cells 24 are arranged along the stacking direction of the positive electrode body 36 and the negative electrode body 37, and the mechanical strength (yield stress) is higher than that of the second reinforcing material 54A at the end in the arrangement direction. A strong first reinforcing material 48 is arranged. Therefore, since the expansion of the battery cell 24 in the Z direction can be suppressed by the first reinforcing material 48, the deformation of the exterior body 12 due to the internal force can be reliably prevented. Further, when an external force in the X direction is applied to the exterior body 12, it is possible to suppress the exterior body 12 from being deformed in the X direction by the first reinforcing material 48. Therefore, it is possible to reliably prevent a short circuit due to deformation of the end portions of the positive electrode body 36 and the negative electrode body 37 due to an external force.

  On the other hand, since each battery cell 24 is strong in the internal force in the X direction, even if it is the second reinforcing material 54A whose mechanical strength (yield stress) is weaker than that of the first reinforcing material 48, the expansion of the battery cell 24 in the X direction. Can be sufficiently prevented. Further, when an external force in the Z direction is applied to the exterior body 12, each battery cell 24 is strong against the external force in the Z direction, so that even the second reinforcing material 54 </ b> A sufficiently deforms the exterior body 12 in the Z direction. Can be prevented. Moreover, in the present embodiment, since the two types of second reinforcing materials 54A and 54B are provided, deformation due to internal force or external force can be prevented more reliably.

  Further, the first reinforcing member 48 is located at the corner where the short side wall 16 and the long side wall 15 intersect, and the bent portions 50 and 51 are formed at the end of the first reinforcing member 48. The rigidity of the exterior body 12 can be improved reliably. Further, since the second reinforcing members 54A and 54B are made of the second metal material having a specific gravity lighter than that of the first reinforcing member 48, the weight of the entire reinforcing member 46 can be reduced. Therefore, in the power storage device 10 using the reinforcing member 46, it is possible to reduce the weight while ensuring a predetermined rigidity. In particular, the first reinforcing material 48 having a high specific gravity is disposed in a portion having a short overall length and a small volume, and the second reinforcing materials 54A and 54B having a light specific gravity are disposed in a portion having a long overall length and a large volume. Moreover, the second reinforcing members 54A and 54B have a strip shape to reduce the volume, and are provided with a through hole 57 as necessary. Therefore, the total weight of the reinforcing member 46 can be reduced, and the power storage device 10 can be reliably reduced in weight.

(Second Embodiment)
FIG. 6 shows the power storage device 10 of the second embodiment. The second embodiment is different from the first embodiment in that the reinforcing member 46 is composed of only the first reinforcing member 48 and the second reinforcing member 54A and is arranged on the outer surface of the exterior body 12. In the second embodiment, it is possible to obtain the same operation and effect as the first embodiment. Moreover, since the reinforcement member 46 should just be assembled | attached to the outer surface of the exterior body 12, workability | operativity can be improved.

(Third embodiment)
FIG. 7 shows a power storage device 10 according to the third embodiment. In the third embodiment, the reinforcing member 46 is composed of only the first reinforcing member 48 and the second reinforcing member 54A, and the reinforcing member 46 is insert-molded in the case main body 13 constituting the exterior body 12 in the first embodiment. It differs from the form. In the third embodiment thus configured, the same operations and effects as in the first embodiment can be obtained. Further, since the reinforcing member 46 is covered with resin and the connecting portion between the first reinforcing member 48 and the second reinforcing member 54A is not exposed to air, corrosion of the connecting portion can be reliably prevented.

  The power storage device 10 of the present invention is not limited to the configuration of the above embodiment, and various modifications can be made.

  For example, the overall length in the lateral direction (X direction) of the first reinforcing material 48 may be longer than the overall length in the lateral direction (Z direction) of the second reinforcing materials 54A and 54B. Further, the first reinforcing material 48 and the second reinforcing materials 54A and 54B may be formed of a non-metallic material such as a resin, and one of the first reinforcing material 48 and the second reinforcing materials 54A and 54B is a metal material. And the other may be formed of a non-metallic material.

  Moreover, the 1st reinforcement material 48 may prepare several strip | belt-shaped 1st reinforcement materials 48 made into predetermined width, and may arrange | position at intervals in the up-down direction (Y direction). A plurality of second reinforcing members 54A and 54B may also be arranged at intervals. Further, the connection between the first reinforcing member 48 and the second reinforcing members 54A and 54B is not limited to the screw shaft 59 and the nut 60, and may be welded with a third metal material. Can be changed.

  In the first embodiment, the reinforcing member 46 may be configured by only the first reinforcing member 48 and the second reinforcing member 54A positioned in the lateral direction, or the second reinforcing member positioned vertically with the first reinforcing member 48. The reinforcing member 46 may be composed of only the material 54B. The two types of second reinforcing materials 54A and 54B may be formed of different materials. In the third embodiment, the entire reinforcing member 46 is covered with resin by insert molding. However, only the connecting portion between the first reinforcing member 48 and the second reinforcing members 54A and 54B is covered with resin by potting or the like. May be.

  Further, the battery cell 24 may have a configuration in which the electrode body 35 is disposed in the case 26 in such a posture that the winding axis Wa is along the vertical direction (Y direction) of the case 26. The electrode body 35 is not limited to a flat winding type, and may be a stacked type in which a plurality of rectangular positive electrode bodies 36, negative electrode bodies 37, and separators 38 are stacked. Moreover, the power storage element is not limited to a square battery in which the electrode body 35 is accommodated in the case 26, and may be a laminated battery in which the laminated electrode body 35 is sealed with a laminate film.

DESCRIPTION OF SYMBOLS 10 Power storage device 12 Exterior body 13 Case main body 14 Bottom wall part 15 Long side wall part 16 Short side wall part 17 Cover body 18 Positive electrode external terminal 19 Negative electrode external terminal 22 Battery module (electric storage element group)
23 Spacer 24 Battery cell (storage element)
26 Case 27 Case body 28 Bottom surface portion 29 Long side surface portion 30 Short side surface portion 31 Cover body 32 Positive electrode terminal 33 Negative electrode terminal 35 Electrode body 36 Positive electrode body (electrode sheet)
37 Negative electrode (electrode sheet)
38 Separator 39 Curved portion 40 Plane portion 42A Positive electrode current collector 42B Negative electrode current collector 43 First joint portion 44 Second joint portion 46 Reinforcing member 48 First reinforcing material 49 Main body 50 First bent portion 51 Second bent portion 52 Reinforcement Rib 54A, 54B Second reinforcing material 55 Through hole 56 Through hole 57 Extract hole 59 Screw shaft 60 Nut

Claims (10)

An exterior body,
A power storage element group arranged in the exterior body, in which a plurality of power storage elements having stacked electrode sheets are arranged along the stacking direction of the electrode sheets,
A reinforcing member disposed between an outer surface of the exterior body and the power storage element group,
The reinforcing member is
A first reinforcing member disposed at an end of the storage element in the arrangement direction and made of a first material;
A second reinforcing member, which is disposed at an end portion in a direction intersecting the arrangement direction of the power storage elements, and made of a second material different from the first material;
The yield stress of the first material is stronger than the yield stress of the second material,
The specific gravity of the first material is heavier than the specific gravity of the second material,
Power storage device. The power storage element includes a pair of first side surface portions that are spaced apart from each other, and a pair of second side surface portions that extend in a direction intersecting the first side surface portions and have a total length shorter than the total length of the first side surface portions. Having a case with
The power storage device according to claim 1, wherein the electrode sheet is stacked from one side to the other of the pair of first side surface portions.   The power storage device according to claim 1, wherein the first reinforcing material is disposed at both ends of the power storage element in the arrangement direction.   4. The power storage device according to claim 1, wherein the second reinforcing material is disposed at both ends in a direction intersecting with an arrangement direction of the power storage elements. 5.   5. The device according to claim 1, wherein the first reinforcing material and the second reinforcing material are connected via a third material different from any of the first material and the second material. The power storage device according to item.   The power storage device according to claim 5, wherein the third material has an ionization tendency that is an intermediate material between the first material and the second material.   The power storage device according to claim 5 or 6, wherein at least a connecting portion between the first reinforcing material and the second reinforcing material is covered with a resin. The exterior body has a rectangular shape including a pair of first surfaces located at both ends in the arrangement direction of the power storage elements and a pair of second surfaces located at both ends in a direction intersecting the arrangement direction of the power storage elements. ,
The power storage device according to any one of claims 1 to 7, wherein the first reinforcing member is located at a corner portion where the first surface and the second surface intersect.   The power storage device according to claim 8, wherein the first reinforcing member includes a main body extending along the first surface, and bent portions bent at both ends of the main body so as to extend along the second surface. .   10. The power storage device according to claim 1, wherein a total length of the first reinforcing material is shorter than a total length of the second reinforcing material.

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