JP2023053834A - power storage device - Google Patents

Abstract

To provide a power storage device capable of suppressing damage of a power storage element.SOLUTION: A power storage device 10 comprises: a plurality of power storage elements 200 arrayed in a first direction (X-axis direction); a pair of end plates 400 holding the plurality of power storage elements 200 therebetween in the first direction; and a pair of coupling members (side plates 500) extending in the first direction, the pair of coupling members being coupled to the pair of end plates 400 while holding the plurality of power storage elements 200 therebetween in a second direction (Y-axis direction) which crosses the first direction. At least one of the pair of end plates 400 includes a first projection 441 extending so as to connect coupling positions of the pair of coupling members with each other and a second projection 442 extending in a direction crossing a predetermined direction in which the first projection 441 extends.SELECTED DRAWING: Figure 2

Description

The present invention relates to a power storage device.

2. Description of the Related Art Conventionally, a power storage device is known in which a plurality of power storage elements such as lithium ion batteries are housed in a pair of divided exterior bodies, and connecting surfaces of the pair of exterior bodies are thermally welded together. In such a power storage device, a pair of flat plate-shaped end plates arranged at positions sandwiching a plurality of power storage elements are also housed in the exterior body (see, for example, Patent Document 1).

JP 2019-79599 A

A power storage device has a characteristic of gradually expanding with charging and discharging. Therefore, as the expansion of the storage element progresses, the end plates may also deform. If the end plate is deformed, the expansion of the storage element cannot be suppressed, and the storage element may be damaged, or the exterior body may be damaged, which may impair the reliability of the storage device.

An object of the present invention is to suppress deterioration in reliability of a power storage device by suppressing deformation of an end plate.

To achieve the above object, a power storage device according to one aspect of the present invention includes: a plurality of power storage elements arranged in a first direction; a pair of end plates sandwiching the plurality of power storage elements in the first direction; A pair of connecting members extending along the first direction, wherein the pair of connecting members are connected to the pair of end plates while sandwiching the plurality of power storage elements in a second direction crossing the first direction. and a member, wherein at least one of the pair of end plates intersects with a first projection extending so as to connect respective connection positions of the pair of connection members and a predetermined direction in which the first projection extends. and a second convex portion extending in the direction.

According to the power storage device of the present invention, deterioration in reliability can be suppressed.

1 is a perspective view showing an appearance of a power storage device according to an embodiment; FIG. FIG. 2 is an exploded perspective view showing each component when the power storage device according to the embodiment is exploded; FIG. 3 is an exploded perspective view showing each component when the power storage device according to the embodiment is further exploded; 1 is a perspective view showing a configuration of an electric storage element according to an embodiment; FIG. 3 is an exploded perspective view showing the configuration of the end plate according to the embodiment; FIG. 3 is an exploded perspective view showing the configuration of the end plate according to the embodiment; FIG. It is the top view which looked at the end plate which concerns on embodiment from the X-axis positive direction. It is a top view which shows the end plate which concerns on a modification.

A power storage device according to an aspect of the present invention includes a plurality of power storage elements arranged in a first direction, a pair of end plates sandwiching the plurality of power storage elements in the first direction, and end plates extending along the first direction. a pair of connecting members, wherein the pair of connecting members are connected to the pair of end plates while sandwiching the plurality of power storage elements in a second direction that intersects the first direction; At least one of the end plates has a first projection extending so as to connect the respective connection positions of the pair of connection members, and a second projection extending in a direction intersecting the predetermined direction in which the first projection extends. have

According to this, at least one end plate has a first projection extending so as to connect the connection positions with the pair of connection members, and a second projection extending in a direction intersecting the predetermined direction in which the first projection extends. A protrusion is provided. Therefore, even if bending forces in various directions act on the end plate, bending of the end plate can be suppressed by the first convex portion and the second convex portion. That is, since the rigidity of the end plate itself is increased, deformation of the end plate can be suppressed. As a result, it is possible to suppress expansion of the power storage element and damage to the exterior body, thereby suppressing a decrease in reliability of the power storage device.

The end plate has a non-arrangement region in which the pair of connecting members is not arranged in a third direction intersecting the first direction and the second direction, and the second protrusion is the non-arrangement region. may be placed in

Here, the non-arranged region of the end plate in which the connecting member is not arranged in the third direction is likely to receive a bending force originating from the connecting position because the connecting member is not arranged. In this aspect, since the non-arranged region is provided with the second convex portion, the non-arranged region of the end plate where the connecting member is not arranged can be reinforced by the second convex portion, and bending of the portion can be suppressed. can. That is, it is possible to suppress the deformation of the easily deformable portion of the end plate, and to more reliably suppress the deformation of the end plate. This makes it possible to further suppress expansion of the power storage element and damage to the exterior body, and more reliably suppress deterioration in the reliability of the power storage device.

The second protrusion may extend from the first protrusion toward the edge of the end plate.

According to this, since the second protrusion extends from the first protrusion toward the edge of the end plate, the second protrusion can increase the rigidity to the vicinity of the edge of the end plate. As a result, the rigidity of the end plate itself is further increased, so that deformation of the end plate can be suppressed more reliably. This makes it possible to further suppress expansion of the power storage element and damage to the exterior body, and more reliably suppress deterioration in the reliability of the power storage device.

The end plate may be formed by stacking a plurality of plates.

According to this, since the end plate is formed by stacking a plurality of plates, it is possible to further increase the rigidity of the end plate itself. Thereby, deformation of the end plate can be suppressed more reliably. Therefore, it is possible to further suppress the expansion of the power storage element and the damage to the exterior body, and to more reliably suppress the deterioration of the reliability of the power storage device.

(Embodiment)
Hereinafter, power storage devices according to embodiments of the present invention (including modifications thereof) will be described with reference to the drawings. It should be noted that the embodiments described below are all comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, manufacturing processes, order of manufacturing processes, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each figure, the same reference numerals are given to the same or similar components.

In the following description and drawings, the direction in which a plurality of energy storage elements are arranged, the direction in which the long sides of the container of the energy storage elements face each other, the direction in which the energy storage elements and the intermediate spacers are arranged, and the direction in which the pair of end plates are arranged are referred to as the X-axis direction. Define. The Y-axis direction is defined as the direction in which a pair of electrode terminals (positive electrode side and negative electrode side) in one energy storage element are aligned, the direction in which the short sides of the container of the energy storage element face each other, or the direction in which a pair of side plates are aligned. The Z-axis direction is defined as the alignment direction of the exterior body and the exterior body cover of the power storage device, the alignment direction of the container body and the container lid of the power storage element, the alignment direction of the power storage element and the bus bar, or the vertical direction. do. The X-axis direction is an example of a first direction, the Y-axis direction is an example of a second direction, and the Z-axis direction is an example of a third direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that cross each other (perpendicularly in this embodiment). Although the Z-axis direction may not be the vertical direction depending on the mode of use, the Z-axis direction will be described below for convenience of explanation.

In the following description, the X-axis plus direction indicates the arrow direction of the X-axis, and the X-axis minus direction indicates the direction opposite to the X-axis plus direction. When simply referred to as the X-axis direction, it indicates either or both of the X-axis plus direction and the X-axis minus direction. The same applies to the Y-axis direction and the Z-axis direction. Expressions indicating relative directions or orientations, such as parallel and orthogonal, also include cases where the directions or orientations are not strictly speaking. For example, two directions being parallel not only means that the two directions are completely parallel, but also being substantially parallel, that is, including a difference of about several percent, for example. means. Furthermore, in the following description, the expression "insulation" means "electrical insulation".

[1 General description of power storage device]
First, a general description of power storage device 10 in the present embodiment will be given. FIG. 1 is a perspective view showing the appearance of a power storage device 10 according to an embodiment. FIG. 2 is an exploded perspective view showing each component when power storage device 10 according to the embodiment is exploded. FIG. 3 is an exploded perspective view showing each component when power storage device 10 according to the embodiment is further exploded. Note that FIG. 3 is an exploded perspective view showing components of power storage device 10 other than exterior body 100 and bus bar 700 in an exploded manner.

Power storage device 10 is a device capable of charging electricity from the outside and discharging electricity to the outside, and has a substantially rectangular parallelepiped shape in the present embodiment. For example, the power storage device 10 is a battery module (assembled battery) used for power storage or power supply. Specifically, the power storage device 10 is, for example, an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, or a rolling stock for an electric railway. It is used as a battery etc. Examples of the vehicles include electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and fossil fuel (gasoline, light oil, liquefied natural gas, etc.) vehicles. Examples of railway vehicles for the electric railway include electric trains, monorails, linear motor cars, and hybrid trains having both diesel engines and electric motors. The power storage device 10 can also be used as a stationary battery or the like for home use, business use, or the like.

As shown in FIG. 1 , power storage device 10 includes exterior body 100 . As shown in FIGS. 2 and 3, inside the exterior body 100 are a plurality of storage elements 200, a plurality of intermediate spacers 300 (310 to 340), a pair of end plates 400 (410, 420), a pair of side Plates 500 (501, 502) and a plurality of busbars 700 and the like are accommodated. In addition to the components described above, the power storage device 10 includes a busbar holder on which the busbar 700 is mounted, a circuit board for monitoring the charging state and the discharging state of the power storage element 200, electric devices such as fuses, relays and connectors, and the like. , an exhaust portion or the like for exhausting the gas discharged from the power storage element 200 to the outside of the exterior body 100 may be provided.

The exterior body 100 is a box-shaped (substantially rectangular parallelepiped) container (module case) that constitutes a housing (outer shell) of the power storage device 10 . The exterior body 100 is arranged outside the plurality of storage elements 200, the plurality of intermediate spacers 300, the pair of end plates 400, the pair of side plates 500, the plurality of bus bars 700, and the like, and the plurality of storage elements 200, etc. , and protect it from impacts. The exterior body 100 is made of, for example, polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate ( PET), polybutylene terephthalate (PBT), polyetheretherketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or , an insulating member such as a composite material thereof, or a metal coated with an insulating coating. The exterior body 100 thereby prevents the power storage element 200 and the like from coming into contact with an external metal member or the like. Note that the exterior body 100 may be made of a conductive material such as metal as long as the electrical insulation of the power storage element 200 and the like is maintained.

The exterior body 100 has an exterior body main body 110 that constitutes the main body of the exterior body 100 and an exterior body lid 120 that constitutes the lid of the exterior body 100 . The exterior body main body 110 is a bottomed rectangular cylindrical housing (casing) with an opening formed on the top, and accommodates the power storage element 200 and the like. The exterior cover 120 is a flat rectangular member that closes the opening of the exterior main body 110 . The exterior body lid 120 is joined to the exterior body main body 110 by an adhesive, heat sealing, ultrasonic welding, or the like. A pair of external terminals 121 (on the positive electrode side and the negative electrode side) are provided on the outer cover body 120 . Power storage device 10 charges electricity from the outside and discharges electricity to the outside through the pair of external terminals 121 .

The storage element 200 is a secondary battery (single battery) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. . Energy storage element 200 has a flat rectangular parallelepiped shape (rectangular shape), and in the present embodiment, eight energy storage elements 200 are arranged side by side in the X-axis direction (first direction). Note that the size and shape of the power storage elements 200, the number of power storage elements 200 to be arranged, and the like are not limited, and for example, only two power storage elements 200 may be arranged. The storage element 200 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The power storage element 200 may be a primary battery that can use stored electricity without being charged by the user, instead of a secondary battery. The storage element 200 may be a battery using a solid electrolyte. The storage element 200 may be a pouch-type storage element. A detailed description of the configuration of the storage element 200 will be given later.

Bus bar 700 is a flat and rectangular member connected to power storage element 200 . The bus bar 700 is arranged above the plurality of power storage elements 200 and connected (joined) to the electrode terminals 240 (see FIG. 4 etc.) of the plurality of power storage elements 200 and the external terminals 121 . In other words, the bus bar 700 connects the electrode terminals 240 of the plurality of storage elements 200 to each other and connects the electrode terminals 240 of the storage elements 200 at the ends to the external terminals 121 .

In the present embodiment, bus bar 700 and electrode terminal 240 or external terminal 121 are connected (joined) by welding, but may be connected (joined) by bolt connection or the like. The bus bar 700 is made of, for example, a conductive member made of metal such as aluminum, aluminum alloy, copper, copper alloy, nickel, or a combination thereof, or a conductive member other than metal. In the present embodiment, bus bar 700 connects two power storage elements 200 in parallel to form four power storage element groups, and connects the four power storage element groups in series. The connection form of the bus bar 700 is not particularly limited, and the plurality of power storage elements 200 may be arranged in any combination to be connected in series or connected in parallel.

Intermediate spacer 300 is a plate-like and rectangular member arranged to the side of power storage element 200 (X-axis plus direction or X-axis minus direction) to electrically insulate power storage element 200 from other members. The intermediate spacer 300 also has a function of holding the power storage element 200 and positioning the power storage element 200 . Among the plurality of intermediate spacers 300, the intermediate spacers 300 arranged between the power storage elements 200 (power storage element group) are also referred to as intermediate spacers 310 to 330. The intermediate spacer 300 arranged between and is also called an intermediate spacer 340 . That is, the plurality of power storage elements 200 and the plurality of intermediate spacers 300 (intermediate spacers 310 to 340) are arranged side by side in the X-axis direction.

The intermediate spacers 310 to 330 are spacers (intermediate spacers) arranged between two adjacent power storage elements 200 to electrically insulate between the two power storage elements 200 . Intermediate spacer 310 is disposed between intermediate spacers 320 and 330 and is thicker and more rigid than intermediate spacers 320 and 330 . The intermediate spacer 310 is made of a metal member such as aluminum, aluminum alloy, iron, stainless steel, plated steel plate, or the like. The material of the intermediate spacer 310 is not particularly limited, and may be formed of an insulating member having high rigidity, or may be subjected to an insulating treatment. The intermediate spacers 320 and 330 are, for example, an electrically insulating member such as any resin material that can be used for the exterior body 100, or a damper material formed by accumulating and bonding mica pieces. It is formed of a member or the like having heat insulating properties such as.

Intermediate spacer 340 is arranged between power storage element 200 at the end and end plate 400 (410, 420) to electrically connect between power storage element 200 at the end and end plate 400 (410, 420). It is an insulating spacer. The intermediate spacer 340 is formed of, for example, an electrically insulating member such as any resin material that can be used for the exterior body 100, or a heat insulating member such as a damper material.

The end plate 400 and the side plate 500 are restraining members that externally press (restrain) the power storage elements 200 in the direction in which the plurality of power storage elements 200 are arranged (the X-axis direction). That is, the end plates 400 and the side plates 500 sandwich the plurality of power storage elements 200 from both sides in the alignment direction, thereby pressing (restraining) the power storage elements 200 included in the plurality of power storage elements 200 from both sides in the alignment direction. )do.

The end plate 400 and the side plate 500 are made of metal members such as aluminum, aluminum alloy, iron, stainless steel, and plated steel plate. The material of the end plate 400 and the side plate 500 is not particularly limited, and may be formed of an insulating member having high rigidity, or may be subjected to an insulating treatment.

Specifically, the end plates 400 are arranged on both sides of the plurality of energy storage elements 200 and the plurality of intermediate spacers 300 (310 to 340) in the X-axis direction, and the plurality of energy storage elements 200 and the like are arranged in the alignment direction (X It is a plate-like member (sandwiching member) that sandwiches and holds from both sides in the axial direction. Of the pair of end plates 400 , the end plate 400 on the positive side of the X axis is also called an end plate 410 , and the end plate 400 on the negative side of the X axis is also called an end plate 420 . That is, the pair of end plates 410 and 420 are arranged at positions sandwiching the plurality of power storage elements 200 and the plurality of intermediate spacers 300 in the X-axis direction (predetermined direction) to sandwich them. Details of the end plate 400 will be described later.

Both ends of the side plate 500 are attached to a pair of end plates 400 (410, 420), and by connecting the pair of end plates 400, the plurality of power storage elements 200 and the plurality of intermediate spacers 300 (310 to 340) are constrained. It is a plate-shaped member that That is, the side plate 500 is a connecting member that extends in the X-axis direction so as to straddle the plurality of power storage elements 200 and the plurality of intermediate spacers 300 and is connected to the pair of end plates 400 . The side plate 500 is connected to the pair of end plates 400 to give a restraining force to the plurality of power storage elements 200 and the like in the direction in which they are arranged (the X-axis direction).

In this embodiment, a pair of side plates 500 are arranged on both sides of the plurality of storage elements 200 and the plurality of intermediate spacers 300 (310 to 340) in the Y-axis direction. In the present embodiment, the pair of side plates 500 are arranged closer to the Z-axis plus direction on both sides of the plurality of power storage elements 200 and the like in the Y-axis direction. Each of the pair of side plates 500 is attached to the ends of the pair of end plates 400 in the Y-axis direction at both ends in the X-axis direction. As a result, the pair of side plates 500 and the pair of end plates 400 sandwich and constrain the plurality of power storage elements 200 and the like from both sides in the X-axis direction and both sides in the Y-axis direction.

Specifically, the side plate 500 has a shape in which both ends in the X-axis direction are bent toward the storage element 200 side. Both ends of the side plate 500 are connected to the end plates 400 (410, 420) by a plurality of (two in this embodiment) connecting members 500a arranged in the Z-axis direction. In the present embodiment, connection member 500a is a bolt, and is coupled by tightening with nut 450 (see FIG. 6) of end plate 400. As shown in FIG. Here, of the pair of side plates 500 , the side plate 500 on the positive side of the Y axis is also called side plate 501 , and the side plate 500 on the negative side of the Y axis is also called side plate 502 .

A plurality of drawn portions 510 are formed at the bent corners of the side plate 500 to increase strength. Each drawn portion 510 is formed by drawing so as to be convex toward the inside of the corner.

[2 Description of storage element]
Next, the configuration of the storage element 200 will be described in detail. FIG. 4 is a perspective view showing the configuration of the storage device 200 according to the embodiment. Specifically, FIG. 4 shows an enlarged appearance of one power storage element 200 out of the plurality of power storage elements 200 shown in FIG. Since all of the plurality of power storage elements 200 have the same configuration, the configuration of one power storage element 200 will be described in detail below.

As shown in FIG. 4 , the storage element 200 includes a container 210 , a pair of electrode terminals 240 (positive electrode side and negative electrode side), and an upper gasket 250 . In addition, a lower gasket, an electrode body, a pair of current collectors (on the positive electrode side and the negative electrode side), an electrolytic solution (non-aqueous electrolyte), and the like are accommodated inside the container 210, but these are not shown in the drawing. omitted. As the electrolytic solution, the type is not particularly limited as long as it does not impair the performance of the electric storage element 200, and various kinds can be selected.

In addition to the components described above, the electric storage element 200 may include spacers disposed on the side or below the electrode body, an insulating film that wraps the electrode body and the like, and the like. Furthermore, an insulating film (shrink tube or the like) covering the outer surface of the container 210 may be arranged around the container 210 . The material of the insulating film is not particularly limited as long as it can ensure the insulation required for the electric storage element 200. Examples include insulating resins such as PC, PP, PE, PPS, PET, PBT, and ABS resins. Epoxy resin, Kapton (registered trademark), Teflon (registered trademark), silicon, polyisoprene, and polyvinyl chloride can be exemplified.

The container 210 is a rectangular parallelepiped (square or box-shaped) case having a container body 220 with an opening and a lid 230 closing the opening of the container body 220 . The container main body 220 is a rectangular cylindrical member having a bottom that constitutes the main body of the container 210, and has an opening formed in the positive direction of the Z axis. The lid body 230 is a rectangular plate-like member that constitutes the lid portion of the container 210 , and is arranged to extend in the Y-axis direction on the Z-axis positive direction side of the container body 220 . The lid 230 includes a gas discharge valve 231 that releases the pressure inside the container 210 when the pressure rises excessively, and a liquid injection part (not shown) for injecting an electrolytic solution into the container 210. ) etc. are provided. The material of the container 210 (the container body 220 and the lid 230) is not particularly limited, and can be, for example, a weldable (bondable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel plate. can also be used. The container 210 has a structure in which the inside is hermetically sealed by joining the container body 220 and the lid 230 by welding or the like after housing the electrode body and the like inside the container body 220 .

The container 210 has a pair of long side surfaces 211 on both side surfaces in the X-axis direction, a pair of short side surfaces 212 on both side surfaces in the Y-axis direction, and a bottom surface 213 on the Z-axis negative direction side. The long side 211 is a rectangular planar portion that forms the long side of the container 210 . Long side 211 adjoins short side 212 and bottom 213 . The short side surface 212 is a rectangular planar portion that forms the short side surface of the container 210 and is arranged to face the side plate 500 in the Y-axis direction. The bottom surface 213 is a rectangular planar portion that forms the bottom surface of the container 210 and is arranged adjacent to the long side surface 211 and the short side surface 212 .

The electrode terminal 240 is a terminal member (a positive electrode terminal and a negative electrode terminal) of the storage element 200 arranged in the lid 230, and is electrically connected to the positive electrode plate and the negative electrode plate of the electrode body via a current collector. there is In other words, the electrode terminal 240 is made of metal for leading electricity stored in the electrode body to the external space of the storage element 200 and for introducing electricity into the internal space of the storage element 200 to store the electricity in the electrode body. It is a member made of The electrode terminal 240 is made of aluminum, aluminum alloy, copper, copper alloy, or the like.

The electrode assembly is a power storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is formed by forming a positive electrode active material layer on a positive electrode substrate layer, which is a collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is formed by forming a negative electrode active material layer on a negative electrode substrate layer, which is a collector foil made of a metal such as copper or a copper alloy. As the active material used for the positive electrode active material layer and the negative electrode active material layer, any known material can be appropriately used as long as it can intercalate and deintercalate lithium ions. A microporous sheet made of resin, a non-woven fabric, or the like can be used as the separator. In the present embodiment, the electrode body is formed by stacking electrode plates (a positive electrode plate and a negative electrode plate) in the X-axis direction. The electrode body includes a wound electrode body formed by winding electrode plates (a positive electrode plate and a negative electrode plate), and a laminated type (stacked) electrode body formed by stacking a plurality of flat plate-shaped electrode plates. or a bellows-shaped electrode body in which an electrode plate is folded into a bellows shape.

The current collectors are conductive members (a positive electrode current collector and a negative electrode current collector) that are electrically connected to the electrode terminal 240 and the electrode body. The positive electrode current collector is made of aluminum, an aluminum alloy, or the like, like the positive electrode substrate layer of the positive electrode plate, and the negative electrode current collector is made of copper, a copper alloy, or the like, like the negative electrode substrate layer of the negative electrode plate. It is

The upper gasket 250 is a gasket that is arranged between the lid 230 and the electrode terminal 240 to insulate and seal between the lid 230 and the electrode terminal 240 . The lower gasket is a gasket that is placed between the lid 230 and the current collector to insulate and seal between the lid 230 and the current collector. The upper gasket 250 and the lower gasket may be made of any material that has electrical insulation.

[3 Explanation of end plate]
Next, the configuration of the end plate 400 (410, 420) will be described in detail. End plate 410 and end plate 420 have the same configuration. Therefore, the configuration of the end plate 410 will be mainly described below, and the configuration of the end plate 420 will conform to the configuration of the end plate 410, and detailed description thereof will be omitted. Specifically, end plate 420 has the same configuration as end plate 410 rotated 180 degrees around the Z-axis.

5 and 6 are exploded perspective views showing the configuration of the end plate 410 according to the embodiment. Specifically, FIG. 5 is an exploded perspective view of the end plate 410 viewed from the positive direction of the X-axis, and FIG. 6 is an exploded perspective view of the end plate 410 viewed from the negative direction of the X-axis. FIG. 7 is a plan view of the end plate 410 according to the embodiment viewed from the positive direction of the X axis. In FIG. 7 , the pair of side plates 500 are illustrated by two-dot chain lines, and the end plate 410 has a non-arrangement area N where the pair of side plates 500 are not arranged in the Z-axis direction.

As shown in FIGS. 5 to 7, the end plate 410 has a first plate 430 and a second plate 460, which are joined and integrated by welding, for example.

The first plate 430 is a plate material laminated on the main surface of the second plate 460 in the plus direction of the X axis, and is sheet metal in this embodiment. Specifically, the first plate 430 has a plurality of protrusions 440 and a plurality of recesses 490 . When the first plate 430 is viewed as a whole, each convex portion 440 is a portion that protrudes in the positive direction of the X axis, and each concave portion 490 is a portion that is recessed in the negative direction of the X axis. A ceiling wall 443 of each convex portion 440 is a flat plate portion parallel to the YZ plane and arranged at the same position in the X-axis direction. Similarly, the bottom wall 491 of each recess 490 is a flat plate portion parallel to the YZ plane and arranged at the same position in the X-axis direction.

The multiple protrusions 440 include a pair of first protrusions 441 extending in the Y-axis direction and a pair of second protrusions 442 extending in the Z-axis direction. Specifically, each first projection 441 extends continuously over the entire first plate 430 in the Y-axis direction. Of the pair of first protrusions 441, one first protrusion 441 is arranged above the first plate 430, and the other first protrusion 441 is located at an intermediate portion of the first plate 430 in the Z-axis direction. are placed in The lower portion of the other first protrusion 441 enters the non-arrangement region N over the entire width (entire length in the Y-axis direction) (see FIG. 7).

A pair of through holes 445 are provided in the top wall 443 of each first protrusion 441 . Specifically, the through-holes 445 are arranged at both ends of the ceiling wall 443 in the Y-axis direction and penetrate in the X-axis direction. A pair of nuts 450 are fixed to the surface of each ceiling wall 443 in the negative direction of the X axis (see FIG. 6). Each nut 450 is fixed to each top wall 443 by welding or the like so that the screw holes are connected to the through holes 445 .

Connecting member 500 a is tightened and coupled to each nut 450 provided in each first projection 441 , thereby coupling the end of side plate 500 and first plate 430 . Specifically, in a state where the end of the side plate 501 is superimposed on the end of the first plate 430 in the positive Y-axis direction, the connection members 500a are connected through the through holes 445 in the positive Y-axis direction. Each nut 450 is tightened and coupled. With the end of the side plate 502 superimposed on the end of the first plate 430 in the negative Y-axis direction, each connecting member 500a is fastened to each nut 450 via each through-hole 445 in the negative Y-axis direction. are joined together. Thus, each through hole 445 in the first plate 430 is a connection position with the pair of side plates 500 . Each first convex portion 441 extends continuously so as to connect the connection positions with the pair of side plates 500 .

Further, in the ceiling wall 443 of each first projection 441, a positioning hole 446 for positioning with the second plate 460 is formed so as to penetrate in the X-axis direction at an intermediate position between the pair of through holes 445. ing.

Each second protrusion 442 continuously extends from the other first protrusion 441 to the lower end of the first plate 430 . Each second convex portion 442 is arranged in the non-arrangement region N of the end plate 410 (see FIG. 7). Specifically, one of the pair of second protrusions 442 is arranged at a position closer to the Y-axis plus direction in the non-placement region N, and the other second protrusion 442 442 is arranged in the non-arrangement area N at a position closer to the Y-axis minus direction. A positioning hole 446 for positioning with the second plate 460 is formed in the ceiling wall 443 of each second projection 442 at an intermediate position in the Z-axis direction so as to penetrate in the X-axis direction.

The multiple recesses 490 are portions of the first plate 430 where the multiple first protrusions 441 are not formed. Specifically, in the first plate 430, the portion above the first protrusion 441 on one side, the portion between the pair of first protrusions 441, and the second protrusion 442 on the one side in the positive Y-axis direction , a portion in the negative Y-axis direction from the other second protrusion 442 , and a portion between the pair of second protrusions 442 are recesses 490 .

In this way, the first plate 430 intersects the first convex portion 441 extending so as to connect the connection positions of the pair of side plates 500 and the predetermined direction (X-axis direction) in which the first convex portion 441 extends. A second convex portion 442 extending in the direction (Z-axis direction) is provided. Therefore, even if bending forces act on the first plate 430 in various directions, the bending of the first plate 430 can be suppressed by the first protrusions 441 and the second protrusions 442 . For example, even if the central portion of the first plate 430 is bent in a curved shape that protrudes in the positive direction of the X-axis when viewed in the Z-axis direction, the pair of first protrusions 441 may extend along the Y-axis direction. The extension suppresses bending of the first plate 430 . Also, even if the lower edge of the first plate 430 were to be bent in the positive X-axis direction when viewed in the Y-axis direction, the pair of second protrusions 442 extending along the Z-axis direction would not Bending of one plate 430 is suppressed.

The second plate 460 is arranged between the first plate 430 and the plurality of power storage elements 200 and is a plate material that overlaps the first plate 430, and is a flat plate-like metal plate in this embodiment. Specifically, the second plate 460 is arranged between the intermediate spacer 340 in the positive X-axis direction and the first plate 430 and directly overlaps them.

As shown in FIG. 7 , the second plate 460 is shaped such that both ends in the Y-axis direction protrude from the first plate 430 . Specifically, both ends of the second plate 460 in the Y-axis direction are protrusions 461 that continuously protrude from the first plate 430 over the entire Z-axis direction. A cutout 462 extending in the Z-axis direction is formed at the lower end of each protrusion 461 .

A portion of the second plate 460 between the pair of projecting portions 461 is an overlapping portion 463 that overlaps the first plate 430 as viewed in the X-axis direction. The overlapping portion 463 overlaps the bottom walls 491 of all the recesses 490 of the first plate 430, and at least a portion thereof is welded to integrate the first plate 430 and the second plate 460. there is

A plurality of positioning holes 464 penetrating in the X-axis direction are formed in the overlapping portion 463 . A plurality of positioning holes 464 are arranged at positions corresponding to the respective positioning holes 446 of the first plate 430 . During manufacturing, the positioning holes 446 of the first plate 430 and the positioning holes 464 of the second plate 460 are made to communicate with each other, and jigs are inserted into the positioning holes 446 and 464 . Thereby, the first plate 430 and the second plate 460 are positioned. By welding in this state, the first plate 430 and the second plate 460 are welded and integrated at regular positions.

Here, the second plate 460 is formed in a flat plate shape and overlaps the bottom walls 491 of the plurality of recesses 490 of the first plate 430 . For example, when the first plate 430 receives an impact from the outside, stress is transmitted from the plurality of recesses 490 to the second plate 460, but since the second plate 460 abuts on the plurality of recesses 490, the stress is dispersed. can be made Therefore, it is possible to suppress the application of a large stress to the storage element 200, and to further suppress damage to the storage element 200. FIG.

Furthermore, while the second plate 460 is formed in a flat plate shape, the first plate 430 has an uneven structure. That is, since the second plate 460 has a smaller surface area than the first plate 430 , the second plate 460 can be made lighter than the first plate 430 . On the other hand, as shown in FIG. 7, the second plate 460 has a larger projected area than the first plate 430 when viewed in the X-axis direction. Therefore, it is also possible to disperse the impact received by the first plate 430 over a wider range.

[4 Explanation of effects]
As described above, according to the power storage device 10 according to the embodiment of the present invention, the end plate 400 includes the first convex portion 441 extending so as to connect the connection positions with the pair of side plates 500 and the corresponding A second protrusion 442 extending in a direction crossing the predetermined direction in which the first protrusion 441 extends is provided. Therefore, even if bending forces in various directions act on the end plate 400 , bending of the end plate 400 can be suppressed by the first convex portion 441 and the second convex portion 442 . That is, since the rigidity of the end plate 400 itself is increased, deformation of the end plate 400 can be suppressed. As a result, expansion of the power storage element 200 and damage to the exterior body 100 can be suppressed, and a decrease in reliability of the power storage device 10 can be suppressed.

In the present embodiment, since the first plate 430 is provided with the concave-convex structure to achieve high rigidity, it is possible to suppress an increase in the weight of the first plate 430 .

Here, since the side plate 500 is not arranged in the non-arrangement area N where the side plate 500 is not arranged in the third direction (Z-axis direction) in the end plate 400, a bending force originating from the connection position is applied. easy to receive. In the present embodiment, since the non-arranged region N is provided with the second convex portion 442, the non-arranged region N of the end plate 400 can be reinforced by the second convex portion 442, and bending of the portion can be suppressed. can. In other words, deformation of easily deformable portions of the end plate 400 can be suppressed, and deformation of the end plate 400 can be suppressed more reliably. As a result, expansion of power storage element 200 and damage to exterior body 100 can be further suppressed, and deterioration in reliability of power storage device 10 can be more reliably suppressed.

Since the second protrusion 442 extends from the other first protrusion 441 to the lower edge of the end plate 400 , the second protrusion 442 can increase the rigidity to the lower edge of the end plate 400 . As a result, the rigidity of the end plate 400 itself is further increased, so that deformation of the end plate 400 can be suppressed more reliably. As a result, expansion of power storage element 200 and damage to exterior body 100 can be further suppressed, and deterioration in reliability of power storage device 10 can be more reliably suppressed.

Since the end plate 400 is formed by stacking the first plate 430 and the second plate 460, it is possible to further increase the rigidity of the end plate 400 itself. Thereby, deformation of the end plate 400 can be suppressed more reliably. Therefore, expansion of power storage element 200 and damage to exterior body 100 can be further suppressed, and deterioration in reliability of power storage device 10 can be more reliably suppressed.

Here, if the first convex portion 441 and the second convex portion 442 are separated, there is a risk that stress will concentrate on the boundary between them, making it easier to bend. In the present embodiment, since the first convex portion 441 and the second convex portion 442 are formed continuously, it is possible to suppress bending of the end plate 400 at the boundary between them. Therefore, the rigidity of the end plate 400 itself can be increased, and deformation of the end plate 400 can be suppressed more reliably.

Moreover, when the first convex portion 441 and the second convex portion 442 protrude in opposite directions, there is a possibility that the stress concentrates on the reversal portion, making it easier to bend. In the present embodiment, since the first protrusion 441 and the second protrusion 442 protrude in the same direction, there is no reversal point and stress is less likely to concentrate. Therefore, the rigidity of the end plate 400 itself can be increased, and deformation of the end plate 400 can be suppressed more reliably.

[5 Description of Modifications]
Although power storage device 10 according to the present embodiment has been described above, the present invention is not limited to the above embodiment. The embodiments disclosed this time are illustrative in all respects and are not restrictive, and the scope of the present invention includes all modifications within the meaning and range of equivalents to the claims. . In the following description, parts that are the same as those in the above-described embodiment are denoted by the same reference numerals, and description thereof may be omitted.

For example, in the above-described embodiment, the end plate 400 in which the second protrusion 442 is provided only in the non-arrangement region N has been exemplified. However, the second convex portion may be provided in areas other than the non-placement area N as well. FIG. 8 is a plan view showing an end plate 410a according to a modification. In the end plate 410a shown in FIG. 8, each second projection 442a is continuously formed from the lower end to the upper end of the first plate 430a, and is also provided in regions other than the non-placement region N. . Therefore, each second protrusion 442a is formed continuously with respect to each first protrusion 441a. In addition, since each second protrusion 442a extends from one first protrusion 441a to the lower edge of the first plate 430a, the second protrusion 442a also increases the rigidity to the lower edge of the first plate 430a. can be done. That is, the rigidity of the end plate 410a is enhanced. In addition, the second convex portion may be provided while avoiding the non-placement region.

Although the two end plates 400 are illustrated in the above embodiment, a single end plate consisting of only the first plate may also be used.

In the above embodiment, the end plate 400 in which the first plate 430 and the second plate 460 are separate members has been exemplified. However, the first plate and the second plate may be continuous end plates by bending one sheet metal.

In the above embodiment, the intermediate spacer 340 is interposed between the end plate 400 and the storage element 200. However, the end plate and the storage element directly overlap each other without the intermediate spacer 340 interposed. may be

In the above-described embodiment, the case where each pair of the first convex portion 441 and the second convex portion 442 is provided is exemplified. However, the number of the first projections 441 and the second projections 442 to be installed is arbitrary.

In the above-described embodiment, the case where the first convex portion 441 extends along the Y-axis direction is exemplified. However, the first convex portion may extend so as to be inclined with respect to the Y-axis direction as long as it extends so as to connect the connection positions with the pair of connection members.

In the above-described embodiment, the case where the second convex portion 442 extends along the Z-axis direction is exemplified. However, as long as the second protrusion intersects the predetermined direction in which the first protrusion extends, the second protrusion may extend obliquely in the Z-axis direction.

In the above embodiment, the pair of end plates 400 have the same configuration. However, only one end plate may have the first protrusion and the second protrusion.

In the embodiment described above, the case where the second protrusion 442 extends from the first protrusion 441 to the edge of the end plate 400 is exemplified. However, the second convex portion may extend only to the middle position of the end plate 400, or may extend only to this side of the edge.

Forms constructed by arbitrarily combining the constituent elements included in the above embodiments and modifications thereof are also included within the scope of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be applied to a power storage device having a power storage element such as a lithium ion secondary battery.

10 power storage device 100 exterior body 110 exterior body main body 120 exterior body lid 121 external terminal 200 storage element 210 container 211 long side 212 short side 213 bottom 220 container body 230 lid 231 gas discharge valve 240 electrode terminal 250 upper gasket 300, 310 , 320, 330, 340 intermediate spacers 400, 410a, 410, 420 end plates 430, 430a first plate 440 projections 441, 441a first projections 442, 442a second projection 443 ceiling wall 445 through hole (connection position)
446, 464 Positioning hole 450 Nut 460 Second plate 461 Projection 462 Notch 463 Overlapping part 490 Recess 491 Bottom wall 500, 501, 502 Side plate (connecting member)
500a connecting member 510 constricted portion 700 busbar N non-placement region

Claims (4)

a plurality of power storage elements arranged in a first direction;
a pair of end plates sandwiching the plurality of power storage elements in the first direction;
A pair of connecting members extending along the first direction, wherein the pair of connecting members are connected to the pair of end plates while sandwiching the plurality of power storage elements in a second direction crossing the first direction. comprising a member and
At least one of the pair of end plates,
a first convex portion extending so as to connect respective connection positions of the pair of connection members;
and a second protrusion extending in a direction intersecting with the predetermined direction in which the first protrusion extends. The end plate has a non-placement region where the pair of connecting members is not placed in a third direction intersecting the first direction and the second direction,
The power storage device according to claim 1, wherein the second convex portion is arranged in the non-arrangement region. The power storage device according to claim 1 or 2, wherein the second protrusion extends from the first protrusion toward the edge of the end plate. The power storage device according to any one of claims 1 to 3, wherein the end plate is formed by stacking a plurality of plates.

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