JP7524893B2 - Power storage device - Google Patents

Description

The present invention relates to an energy storage device having a plurality of energy storage elements.

Patent Document 1 discloses an energy storage device having a group of storage batteries. In this energy storage device, rectangular end plates are arranged on both ends of the stacking direction of the storage battery group, with insulator plates having heat-insulating and insulating functions interposed between them. The end plates are connected to each other by a pair of connecting bands extending in the stacking direction.

JP 2001-236937 A

Suppressing the swelling of each storage element in a storage element string consisting of multiple storage elements can lead to malfunctions in the containers of each storage element or malfunctions in the exterior body housing the storage element string. Therefore, suppressing the swelling of each storage element in a storage element string is important from the perspective of improving the safety of the storage device. To address this issue, it is possible to suppress the swelling of each storage element by restraining the storage element string with connecting bands at a pair of end plates, as in the conventional storage device described above.

However, in the energy storage device of Patent Document 1, an end plate larger than the end face of the energy storage element row (the outer surface of the insulator plate) abuts against the end face. Therefore, if a large external force acts on the energy storage device in the direction in which the energy storage elements are arranged, the end plate will press against the entire end face, which may damage the corners of the end face. To prevent such an event, it is possible to suppress deformation of the end plate by making the end plate thicker. However, this measure is not desirable as it increases the size or weight of the energy storage device.

The present invention aims to provide an energy storage device having multiple energy storage elements, which has improved safety.

An energy storage device according to one embodiment of the present invention comprises an energy storage element unit having a plurality of energy storage elements, and an end member having a portion arranged on a side of the energy storage element unit in a first direction, the end member including an inner plate material and an outer plate material arranged in a stacked manner in the first direction, the inner plate material abutting a first side surface which is the side surface of the energy storage element unit facing the first direction and being arranged between the energy storage element unit and the outer plate material, and in a second direction intersecting the first direction, the width of the inner plate material is smaller than the width of the first side surface of the energy storage element unit, and the width of the outer plate material in the second direction is larger than the width of the inner plate material in the second direction.

According to the present invention, it is possible to provide an energy storage device having a plurality of energy storage elements, which has improved safety.

FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. FIG. 2 is an exploded perspective view showing the internal configuration of the electricity storage device according to the embodiment. FIG. 3 is an exploded perspective view showing a detailed internal configuration of the electricity storage device according to the embodiment. FIG. 4 is a perspective view illustrating the end member according to the embodiment separated from the energy storage element unit. FIG. 5 is an exploded perspective view showing an end member and an energy storage element unit according to the embodiment. FIG. 6 is a perspective view showing the relationship in size between the components of the end member and the width of the unit end face according to the embodiment. FIG. 7 is a front view showing the relationship in size between the components of the end member and the vertical width of the unit end face according to the embodiment. FIG. 8 is a perspective view of an end member according to the embodiment.

An energy storage device according to one embodiment of the present invention comprises an energy storage element unit having a plurality of energy storage elements, and an end member having a portion arranged on a side of the energy storage element unit in a first direction, the end member including an inner plate material and an outer plate material arranged in a stacked manner in the first direction, the inner plate material abutting a first side surface which is the side surface of the energy storage element unit facing the first direction and being arranged between the energy storage element unit and the outer plate material, and in a second direction intersecting the first direction, the width of the inner plate material is smaller than the width of the first side surface of the energy storage element unit, and the width of the outer plate material in the second direction is larger than the width of the inner plate material in the second direction.

According to the energy storage device of this aspect, at least the first side of the energy storage element unit is protected by the end member. The end member has a portion where at least two plate materials are overlapped, so that the strength required for protection can be obtained. Furthermore, since the width of the inner plate material is smaller than the width of the first side of the energy storage element unit, and the width of the outer plate material is larger than the width of the inner plate material, there is a space that facilitates the deformation of the outer plate material inward. Therefore, when a large external force toward the energy storage element unit acts on the outer plate material, the outer plate material can absorb the external force by deforming. This reduces the possibility of damaging the energy storage element unit. In other words, the end member according to this aspect has a predetermined strength by overlapping multiple plate materials, and also has a deformation ability that can absorb impacts because the width of the outer plate material is larger than the width of the inner plate material. Therefore, the energy storage device according to this aspect is an energy storage device with improved safety.

In a third direction intersecting the first direction and the second direction, the width of the inner plate material is smaller than the width of the first side surface of the energy storage element unit, and the inner plate material may be positioned within the area of the outline of the first side surface when viewed from the first direction.

According to this configuration, the inner plate material is formed to be smaller than the outline of the first side surface of the energy storage element unit when viewed from the first direction, and is positioned within the area of the outline of the first side surface. This increases the space in which the outer plate material can easily deform inward, improving the effect of absorbing external forces by the outer plate material, and as a result, improving the safety of the energy storage device.

Each of the multiple storage elements may be arranged in a line in the first direction with its long side facing in the first direction.

According to this configuration, the end member is disposed on the outside of the long side of the energy storage element located at the end in the first direction. This protects the long side, which is a part of the energy storage element that is easily deformed, and efficiently suppresses expansion of the long side. As a result, the safety of the energy storage device is improved.

Each of the plurality of storage elements may be arranged side by side with its short side facing the first direction and with the long sides of two adjacent storage elements facing each other.

According to this configuration, the end members are arranged on the outside of the short side surfaces of the multiple energy storage elements. As a result, when a current collector is arranged inside the energy storage element near the short side surface, the short side surface is protected by the end members, reducing the possibility that the current collector will damage the electrode body if the energy storage device is subjected to an impact. As a result, the safety of the energy storage device is improved.

The end member may further have an intermediate plate material arranged between the inner plate material and the outer plate material, the intermediate plate material having a first intermediate plate portion facing the inner plate material and a second intermediate plate portion facing a second side surface adjacent to the first side surface of the energy storage element unit, and the outer plate material may have a first outer plate portion facing the first intermediate plate portion of the intermediate plate material and a second outer plate portion facing the second intermediate plate portion of the intermediate plate material.

With this configuration, the end member protects both the first and second sides of the energy storage element unit, thereby further improving the safety of the energy storage device.

The end members are arranged on each side of the energy storage element unit in the first direction, and the second outer plate portion of the outer plate material of one of the two end members may have a connecting portion that is connected to the second outer plate portion of the outer plate material of the other of the two end members.

According to this configuration, the pair of end members protect both first side surfaces in the first direction of the energy storage element unit, and the second side surface connecting these first side surfaces.
The pair of end members are mechanically connected to each other by connecting the two second outer plate portions, so that one end member functions as a member reinforcing the other end member, thereby further improving the safety of the energy storage device.

The present invention can also be realized as an end member arranged on a storage element unit including multiple storage elements.

The following describes an energy storage device according to an embodiment of the present invention with reference to the drawings. The embodiments described below are comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection forms, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Among the components in the following embodiments, components that are not described in an independent claim that represents the highest concept are described as optional components. In each figure, dimensions, etc. are not strictly illustrated.

In the following description and drawings, the longitudinal direction of the housing (the direction in which the short sides of the housing face each other) or the direction in which the short sides of one storage element face each other is defined as the X-axis direction. The transverse direction of the housing (the direction in which the long sides of the housing face each other) or the direction in which the long sides of one storage element face each other is defined as the Y-axis direction. The direction in which the main body and the fixed wall are arranged in the housing, or the longitudinal direction of the short side of the storage element is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). In this embodiment, the Z-axis direction is the up-down direction, and the positive side of the Z-axis direction is the "up" direction, but this does not limit the position of the actual storage device when it is in use. In each drawing, in order to show the present invention, the actual shape, positional relationship, and ratio may differ by appropriately emphasizing, omitting, or adjusting the ratio.

The positive side of the X-axis direction refers to the side in the direction of the arrow on the X-axis, and the negative side of the X-axis direction refers to the opposite side to the positive side of the X-axis. The same applies to the Y-axis and Z-axis directions. Furthermore, expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the direction or attitude is not strictly speaking the same. Two directions being orthogonal does not only mean that the two directions are completely orthogonal, but also means that they are substantially orthogonal, that is, there is a difference of about a few percent.

(Embodiment)
[1. General Description of the Power Storage Device]
First, an overall description of an energy storage device 10 according to an embodiment will be given with reference to Figures 1 to 3. Figure 1 is a perspective view showing the external appearance of the energy storage device 10 according to an embodiment. Figure 2 is an exploded perspective view showing the internal configuration of the energy storage device 10 according to an embodiment. Figure 3 is an exploded perspective view showing a detailed internal configuration of the energy storage device 10 according to an embodiment. In Figures 2 and 3, the power cables 20 and electric wires 30 that connect the energy storage device 10 to an external device are omitted.

The power storage device 10 is a device that can charge electricity from an external source and discharge electricity to the outside. The power storage device 10 is a battery module used for power storage or power supply purposes. Specifically, the power storage device 10 is used for driving a mobile object such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), a motorcycle, a watercraft, a snowmobile, an agricultural machine, or a construction machine, for starting an engine or for backup, or for stationary use for home use or as a generator.

As shown in Figures 1 to 3, the energy storage device 10 comprises a storage element unit 200 having a plurality of storage elements 210, and a housing 100 that houses the storage element unit 200. In this embodiment, the storage element unit 200 has four storage elements 210. The number of storage elements 210 in the storage element unit 200 is not limited to four. It is sufficient that the storage element unit 200 comprises a plurality of storage elements 210.

The housing 100 has a fixed wall portion 140 provided with a fixing portion 145 for fixing the energy storage device 10 to another member 500, and a box-shaped main body portion 105 that forms a space between the fixed wall portion 140 and the box-shaped main body portion 105 to accommodate the energy storage element unit 200 and the like. As shown in FIG. 3, the fixed wall portion 140 has a plurality of screw holes 146 for fixing the energy storage element unit 200. Each of a plurality of bolts 50 that pass through the end member 300 (described later) is screwed into the screw holes 146, thereby fixing the end member 300 and the energy storage element unit 200 to the upper surface of the fixed wall portion 140. Furthermore, the main body portion 105 is arranged to surround the end member 300 and the energy storage element unit 200.

That is, the various elements such as the energy storage element unit 200 are arranged on the upper surface of the fixed wall portion 140, which is generally flat, and the main body portion 105 is arranged so as to cover the energy storage element unit 200 from above and the sides. The fixing portion 145 of the fixed wall portion 140 has a fixing opening 145a, and the end of the main body portion 105 has a fixing opening 106. The bolt 40 inserted through the fixing opening 106 and the fixing opening 145a is screwed into a screw hole (or nut) of the other member 500. That is, the main body portion 105 and the fixed wall portion 140 are fastened together to the other member 500 by the bolt 40. In this embodiment, four such fixing points are provided for the housing 100, and the energy storage device 10 is fixed to the other member 500 by these four fixing points.

As shown in FIG. 1, one wall (the wall on the positive side in the X-axis direction) of the main body 105 is provided with an exhaust pipe 190 and an external connection part 195 arranged above the exhaust pipe 190. The exhaust pipe 190 is a member for directing gas to the outside of the housing 100 when gas is discharged from the gas discharge valve of one or more storage elements 210 in the housing 100. The external connection part 195 is a member for holding a pair of power cables 20 connected to the positive and negative electrodes of the storage element unit 200 and a plurality of electric wires 30 connected to a BMU (Battery Management Unit) 400 described later. In FIG. 1, the pair of power cables 20 and the plurality of electric wires 30 are extended to the outside from the external connection part 195, but each of the pair of power cables 20 and the plurality of electric wires 30 may have a connector for connecting to an external device at the position of the external connection part 195.

Since the housing 100 is made of a metal such as iron and has a box-shaped main body 105, the energy storage device 10 has the characteristic of being relatively small and having a strong outer shell (i.e., the housing 100). Therefore, the energy storage device 10 is mounted on an automobile as a battery for operating electrical equipment mounted on the automobile, or as a backup battery to ensure said operation. Therefore, the body of the automobile is an example of the other member 500 to which the energy storage device 10 is fixed. In Figures 1 and 2, the other member 500 is simply shown as a rectangular plate-shaped member, but there is no particular limitation on the size and shape of the other member 500 as long as it has a portion to which the energy storage device 10 can be fixed.

The housing 100 has a support wall portion 110, which is one of the multiple wall portions other than the fixed wall portion 140, and the support wall portion 110 has an attachment portion 120 for attaching a supported member. A supported member larger than the support wall portion 110 can be attached to the attachment portion 120 when viewed from the side of the supported member. The attachment portion 120 has an attachment hole 120a that screws with a bolt or the like for attaching the supported member. When the storage device 10 is mounted on a car, since the storage device 10 is relatively small, it can be placed between the driver's seat and the passenger seat. In this case, a console box including a drink holder or the like can be attached to the four attachment portions 120 arranged on the support wall portion 110 in this embodiment. In other words, the storage device 10 can function as a support member that supports the console box.

In this embodiment, the housing 100 further houses a BMU (Battery Management Unit) 400 that controls the charging and discharging of the energy storage element unit 200. The BMU 400 is fixed to the upper surface of the fixed wall portion 140 with a number of bolts. It is not essential that the energy storage device 10 incorporates the BMU 400, and the charging and discharging of the energy storage element unit 200 may be controlled by an external device.

2 and 3, the energy storage element unit 200 is held in a state sandwiched between end members 300 facing each other in the arrangement direction (Y-axis direction) of the energy storage elements 210. On the electrode terminal side (positive side in the Z-axis direction) of the energy storage element unit 200, a plurality of bus bars 250 that electrically and mechanically connect the plurality of energy storage elements 210 and a bus bar frame 255 that holds the plurality of bus bars 250 are arranged. The bus bar frame 255 is provided with a plurality of bus bar openings 256, and each of the plurality of bus bars 250 is arranged in one of the plurality of bus bar openings 256 and joined to one or two energy storage elements 210 below it.

In this embodiment, a cover member 280 is further disposed above the energy storage element unit 200, and a bus bar 250 is disposed between the energy storage element unit 200 and the cover member 280. In other words, a bus bar frame 255 is disposed between the energy storage element unit 200 and the cover member 280.

[2. Configuration of Energy Storage Element Unit and Its Periphery]
Next, the configuration of the energy storage element unit 200 and its surroundings in the energy storage device 10 configured as above will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a perspective view illustrating the end member 300 according to the embodiment separated from the energy storage element unit 200. Fig. 5 is an exploded perspective view illustrating the end member 300 and the energy storage element unit 200 according to the embodiment in an exploded state.

As shown in Figure 4, the energy storage device 10 according to this embodiment includes an end member 300 having a portion that is arranged on the side of the energy storage element unit 200 in the Y-axis direction. The Y-axis direction is an example of a first direction, which in this embodiment coincides with the arrangement direction of the multiple energy storage elements 210 in the energy storage element unit 200. As shown in Figure 5, the multiple energy storage elements 210 are arranged in the Y-axis direction with their long sides 211 perpendicular to the Y-axis direction (in other words, their short sides 212 parallel to the Y-axis direction).

As shown in FIG. 5, the energy storage element unit 200 has a plurality of energy storage elements 210, a spacer 220 arranged between two adjacent energy storage elements 210, and end spacers 225 arranged at both ends of the arrangement direction (Y-axis direction) of the plurality of energy storage elements 210. That is, in this embodiment, the unit end face 201, which is the side face in the Y-axis direction of the energy storage element unit 200, is formed by the outer surface of the end spacer 225. The unit end face 201 is an example of a first side face. In this embodiment, the unit end face 201 is not a simple flat surface, but has a concave or convex portion (uneven portion) as shown in FIG. 4. Therefore, when "contacting the unit end face 201", it includes not only contacting the flat portion of the unit end face 201, but also contacting the surface of the uneven portion.

The end member 300 is positioned in contact with the unit end face 201. Specifically, the end member 300 is composed of an inner plate material 310 that abuts the unit end face 201 and a plate material arranged on the outside of the inner plate material 310. In this embodiment, an intermediate plate material 320 and an outer plate material 330 are arranged on the outside of the inner plate material 310. Each of the intermediate plate material 320 and the outer plate material 330 is an example of an "outer plate material" in relation to the inner plate material 310.

Each of the inner plate material 310, intermediate plate material 320, and outer plate material 330 is produced by performing press processing or the like on a plate material of a metal such as iron. Furthermore, the end member 300 is produced by welding these plate materials together. The inner plate material 310 and the intermediate plate material 320 are stacked and welded. Of the inner plate material 310 and intermediate plate material 320 integrated by welding, the intermediate plate material 320 is welded to the outer plate material 330 through a plurality of joining openings 312 (see FIG. 5) provided in the inner plate material 310. This forms the end member 300 having a structure in which the inner plate material 310, intermediate plate material 320, and outer plate material 330 are stacked.

As shown in Figures 4 and 5, the intermediate plate material 320 has a first intermediate plate portion 321 facing the inner plate material 310 and a second intermediate plate portion 325 facing the unit side surface 202. The unit side surface 202 is a side surface adjacent to the unit end surface 201. In this embodiment, the unit side surface 202 is an example of a second side surface, and is a side surface in the X-axis direction of the energy storage element unit 200. In other words, the first intermediate plate portion 321 and the second intermediate plate portion 325 are connected in a mutually orthogonal orientation. The second intermediate plate portion 325 is provided at both ends of the first intermediate plate portion 321 in the X-axis direction. The intermediate plate material 320 configured in this manner is arranged with respect to the energy storage element unit 200 as part of the end member 300 in a state in which it surrounds the end portion in the Y-axis direction of the energy storage element unit 200 from three directions.

As shown in Figures 4 and 5, the outer plate material 330 has a first outer plate portion 331 facing the first intermediate plate portion 321 of the intermediate plate material 320, and a second outer plate portion 335 facing the second intermediate plate portion 325 of the intermediate plate material 320. In other words, the first outer plate portion 331 and the second outer plate portion 335 are connected in a mutually perpendicular orientation. The second outer plate portion 335 is provided at both ends of the first outer plate portion 331 in the X-axis direction. The outer plate material 330 configured in this manner is arranged with respect to the energy storage element unit 200 as part of the end member 300 in a state in which it surrounds the end portion in the Y-axis direction of the energy storage element unit 200 from three directions.

The second intermediate plate portion 325 of the intermediate plate material 320 has a through hole 325a in the part that opens outward at the lower end, and the second outer plate portion 335 of the outer plate material 330 has a through hole 335a in the part that opens outward at the lower end. When the intermediate plate material 320 and the outer plate material 330 are combined, the through hole 335a of the outer plate material 330 is positioned directly above the through hole 325a of the intermediate plate material 320. Furthermore, the bolt 50 is inserted through the through hole 335a and the through hole 325a and screwed into the screw hole 146 of the fixed wall portion 140 (see FIG. 3). As a result, the end member 300 and the energy storage element unit 200 are fixed to the fixed wall portion 140. Although not shown in Figures 4 and 5, the end member 300 also has a through hole 335a and a through hole 325a on the negative side in the X-axis direction, and one end member 300 is fixed to the fixed wall portion 140 with two bolts 50.

In this embodiment, the end members 300 having the above-mentioned configuration are arranged on both sides of the energy storage element unit 200 in the Y-axis direction, as shown in Figures 4 and 5. The pair of end members 300 are connected by a connecting plate 380 arranged above the energy storage element unit 200.

Specifically, the two shafts 329 provided on the end members 300 are inserted into the two through holes of the connecting plate 380 and tightened with nuts 90. By performing this operation for each of the pair of end members 300, the pair of end members 300 are connected by the connecting plate 380.

The two shafts 329 are fixed to the intermediate plate 320. Specifically, the intermediate plate 320 has a protruding portion 328 that protrudes from the upper end of the first intermediate plate 321 toward the upper side of the energy storage element unit 200, and the protruding portion 328 is provided with a shaft 329 that stands upright upward. The outer plate 330 has a protruding portion 332 that protrudes from the upper end of the first outer plate 331 toward the upper side of the energy storage element unit 200, and the protruding portion 332 is provided with a through hole 332a through which the shaft 329 passes. When the intermediate plate 320 and the outer plate 330 are combined, the two shafts 329 of the intermediate plate 320 are inserted into the two through holes 332a of the outer plate 330. As a result, the two shafts 329 are arranged at the upper end of the end member 300.

Furthermore, the pair of end members 300 have a structure in which the outer plate materials 330 are fastened to each other by bolts 60 and nuts 62. Specifically, the second outer plate portion 335 of the outer plate material 330 located at the outermost position in the end member 300 is provided with a connecting portion 336 that is connected to the second outer plate portion 335 of the connecting partner end member 300. In this embodiment, the connecting portion 336 is formed by bending the tip portion of the second outer plate portion 335 outward, and is provided on the second outer plate portion 335 as a plate-shaped portion parallel to the first outer plate portion 331. The connecting portion 336 has a plurality of through holes 336a (three in this embodiment). As shown in FIG. 5, when two end members 300 are combined, the through hole 336a of the connecting portion 336 of one end member 300 and the through hole 336a of the connecting portion 336 of the other end member 300 are overlapped in the Y-axis direction. Furthermore, nuts 62 are screwed onto the bolts 60 inserted through these two through holes 336a. Six fastening points are provided using such bolts 60 and nuts 62. In other words, both ends in the X-axis direction of one of the two end members 300 and both ends in the X-axis direction of the other end member 300 are fastened to each other at six points.

That is, the two end members 300 sandwiching the energy storage element unit 200 therebetween are connected by a connecting plate 380 disposed above, and both left and right ends (X-axis direction) are fastened. This allows one of the two end members 300 to firmly restrain the other in the front-to-back direction (Y-axis direction). The two end members 300 connected to each other in this manner are fastened to the fixed wall portion 140 by a plurality of bolts 50. That is, the two end members 300 and the energy storage element unit 200 sandwiched between them are firmly fixed to the fixed wall portion 140.

[3. Size and shape of each plate material in the end member]
The end member 300 disposed in contact with the side surface of the energy storage element unit 200 is formed of a plurality of overlapping plate materials, and in this embodiment, the sizes and shapes of these plate materials are different from one another. This point will be described with reference to Figs. 6 to 8.

Figure 6 is a perspective view showing the relationship between the components of the end member 300 and the horizontal width of the unit end face 201 according to the embodiment. Figure 7 is a front view showing the relationship between the components of the end member 300 and the vertical width of the unit end face 201 according to the embodiment. Figure 8 is a perspective view of the end member 300 according to the embodiment. In Figures 6 and 7, the "horizontal width" is the width in the X-axis direction, and the "vertical width" is the width in the Z-axis direction. Figure 7 shows a view of the energy storage element unit 200 as viewed from the side of the unit end face 201, and the approximate arrangement area of the inner plate material 310 relative to the unit end face 201 is illustrated as the inner plate arrangement area 310a (the area marked with dots).

6, among the multiple plate materials constituting the end member 300, the width Wa of the inner plate material 310 abutting the unit end face 201 is smaller than the width Ws of the unit end face 201. The width Wb of the intermediate plate material 320 located outside the inner plate material 310 in the end member 300 and the width Wc of the outer plate material 330 are both larger than the width Wa of the inner plate material 310. The width Wc of the outer plate material 330 is larger than the width Wb of the intermediate plate material 320. The width Wc of the outer plate material 330 and the width Wb of the intermediate plate material 320 are each based on the portion facing the unit end face 201 in the Y-axis direction. In other words, the width Wc of the outer plate material 330 is the width of the first outer plate portion 331, and the width Wb of the intermediate plate material 320 is the width of the first intermediate plate portion 321. This also applies to the vertical width of the outer plate material 330 and the vertical width of the intermediate plate material 320.

In this way, the inner plate material 310, whose width is smaller than that of the unit end face 201, abuts against the unit end face 201, and the intermediate plate material 320 and the outer plate material 330, whose width is larger than that of the inner plate material 310, are arranged on the outside of the inner plate material 310. The inner plate material 310 is not arranged significantly biased toward the positive or negative side of the X-axis direction relative to the intermediate plate material 320 and the unit end face 201. The center of the inner plate material 310 in the X-axis direction coincides (including approximately coincidence, the same below) with the center of the intermediate plate material 320 and the unit end face 201 in the X-axis direction. In other words, the end of the inner plate material 310 on the positive or negative side in the X-axis direction is separated by a predetermined distance in the X-axis direction from the second intermediate plate portion 325 of the intermediate plate material 320 and the unit end face 202.

As shown in Figure 7, of the multiple plate materials constituting the end member 300, the vertical width Ha of the inner plate material 310 abutting the unit end face 201 is smaller than the vertical width Hs of the unit end face 201. The vertical width Hb of the intermediate plate material 320 and the vertical width Hc of the outer plate material 330 located outside the inner plate material 310 in the end member 300 are both larger than the vertical width Ha of the inner plate material 310. The vertical width Hc of the outer plate material 330 is larger than the vertical width Hb of the intermediate plate material 320. In this way, the inner plate material 310, whose vertical width is smaller than the unit end face 201, abuts the unit end face 201, and the intermediate plate material 320 and the outer plate material 330, whose vertical width is larger than that of the inner plate material 310, are arranged on the outside of it. In other words, in this embodiment, the inner plate material 310 is small in both the length and width of the unit end face 201, and when viewed from the Y-axis direction, is positioned at a position (inner plate arrangement area 310a) within the outer area of the unit end face 201, as shown in Figure 7.

The inner plate material 310 is not positioned significantly biased toward the positive or negative side in the Z-axis direction relative to the intermediate plate material 320 and the unit end face 201. The center of the inner plate material 310 in the Z-axis direction coincides with the center of the intermediate plate material 320 and the unit end face 201 in the Z-axis direction.

[4. Effects, etc.]
As described above, the energy storage device 10 according to the present embodiment includes the energy storage element unit 200 having a plurality of energy storage elements 210, and the end member 300 having a portion disposed on the side of the energy storage element unit 200 in the first direction (the Y-axis direction in this embodiment). The end member 300 includes an inner plate material 310 and an outer plate material 330 disposed in a stacked manner in the Y-axis direction. The inner plate material 310 abuts against a unit end face 201, which is a side face of the energy storage element unit 200 in the Y-axis direction. The inner plate material 310 is disposed between the energy storage element unit 200 and the outer plate material 330, and in a second direction (the X-axis direction in this embodiment) intersecting the Y-axis direction, the width of the inner plate material 310 is smaller than the width of the unit end face 201. The width of the outer plate material 330 in the X-axis direction is larger than the width of the inner plate material 310 in the X-axis direction.

According to this configuration, at least the unit end surface 201 side of the energy storage element unit 200 is protected by the end member 300. The end member 300 has a portion where at least two plate materials are overlapped, so that the strength required for protection can be obtained. Furthermore, since the width of the inner plate material 310 is smaller than the width of the unit end surface 201 and the width of the outer plate material 330 is larger than the width of the inner plate material 310, there is a space that makes it easy to deform the outer plate material 330 inward. In other words, as shown in FIG. 8, there is a space where the inner plate material 310 is not arranged at the end of the outer plate material 330 in the X-axis direction. This space is a space where the deformation of the outer plate material 330 inward is not hindered by the inner plate material 310. Therefore, when a large external force toward the energy storage element unit 200 acts on the outer plate material 330, the outer plate material 330 can absorb the external force by deforming. This reduces the possibility of the energy storage element unit 200 being damaged. In other words, the end member 300 according to this embodiment has a predetermined strength by being made up of a plurality of overlapping plate materials, and also has a deformability capable of absorbing shock because the width of the outer plate material 330 is greater than the width of the inner plate material 310. In this manner, the energy storage device 10 according to this embodiment is an energy storage device with improved safety.

More specifically, the end member 300 does not have an overall large thickness, but rather has a localized large thickness, which ensures rigidity where high rigidity is required and also ensures space for deformation of the end member 300. Furthermore, in the end member 300, the difference in thickness between parts is achieved by stacking multiple plate materials, so that the end member 300 is easier to manufacture than cutting the end member 300 out of a single material or manufacturing the end member 300 using a mold.

In this embodiment, in the end member 300, two adjacent plate materials (the inner plate material 310 and the intermediate plate material 320, and the intermediate plate material 320 and the outer plate material 330) are mechanically connected by welding. Therefore, compared to a case where two adjacent plate materials are connected by bolts and nuts, rivets, etc., the weight of the storage device 10 and the number of parts can be reduced. This has the effect of saving space and reducing the weight of the storage device 10.

By making the size of the inner plate material 310 approximately the same as the unit end face 201 and forming the outer plate material 330 larger than the inner plate material 310, it is possible to form a space that facilitates the inward deformation of the outer plate material 330. However, in this case, another problem arises in that the storage device 10 becomes larger. In this regard, in the storage device 10 of this embodiment, the width of the inner plate material 310 is made smaller than the width of the unit end face 201, which prevents the storage device 10 from becoming larger and ensures a space that facilitates the inward deformation of the outer plate material 330.

In the description of the above configuration and its effects, the "outer plate material 330" can be replaced with the "intermediate plate material 320". That is, as explained using FIG. 6, the width of the intermediate plate material 320 arranged outside the inner plate material 310 is larger than the width of the inner plate material 310. Therefore, as shown in FIG. 8, there is a space in which the inner plate material 310 is not arranged at the end of the intermediate plate material 320 in the X-axis direction, and this space is a space in which the inner deformation of the intermediate plate material 320 is not hindered by the inner plate material 310. Therefore, the intermediate plate material 320 can deform so as to protect the energy storage element unit 200. Furthermore, in the description of the above configuration and its effects, the second direction "X-axis direction" can be replaced with "Z-axis direction". That is, as explained using FIG. 7, the vertical width of the outer plate material 330 arranged outside the inner plate material 310 is larger than the vertical width of the inner plate material 310. Therefore, at the end of the outer plate material 330 in the Z-axis direction, there is a space where the inner plate material 310 is not arranged, and this space is a space where the inward deformation of the outer plate material 330 is not hindered by the inner plate material 310. Therefore, the outer plate material 330 can deform so as to protect the energy storage element unit 200.

In this embodiment, in a third direction (Z-axis direction in this embodiment) that intersects with the first direction (Y-axis direction) and the second direction (X-axis direction), the width of the inner plate material 310 is smaller than the width of the unit end face 201. When viewed from the Y-axis direction, the inner plate material 310 is disposed within the area of the outer shape of the unit end face 201 (see FIG. 7).

That is, in this embodiment, the inner plate material 310 is formed to be smaller than the outer shape of the unit end face 201 when viewed from the X-axis direction, and is arranged within the area of the outer shape of the unit end face 201. Therefore, the space that facilitates the deformation of the outer plate material 330 is increased, thereby improving the effect of absorbing external forces by the outer plate material 330. As a result, the safety of the storage device 10 is improved. This also applies to the intermediate plate material 320 between the inner plate material 310 and the outer plate material 330. In other words, since the inner plate material 310 is smaller than the unit end face 201, the space that facilitates the deformation of the intermediate plate material 320 is increased, thereby improving the effect of absorbing external forces by the intermediate plate material 320. This contributes to improving the safety of the storage device 10.

In this embodiment, each of the multiple storage elements 210 is arranged in a line in the Y-axis direction with the long side 211 facing the Y-axis direction.

That is, the end member 300 is disposed on the outside of the long side surface 211 of the energy storage element 210 located at the end in the Y-axis direction. This protects the long side surface 211, which is a part of the energy storage element 210 that is easily deformed, and efficiently suppresses expansion of the long side surface 211. As a result, the safety of the energy storage device 10 is improved.

In this embodiment, the end member 300 has an intermediate plate material 320 arranged between the inner plate material 310 and the outer plate material 330. The intermediate plate material 320 has a first intermediate plate portion 321 facing the inner plate material 310, and a second intermediate plate portion 325 facing the unit side surface 202 of the energy storage element unit 200. The outer plate material 330 has a first outer plate portion 331 facing the first intermediate plate portion 321 of the intermediate plate material 320, and a second outer plate portion 335 facing the second intermediate plate portion 325 of the intermediate plate material 320.

With this configuration, the end member 300 protects both the unit end face 201 and the unit side face 202 of the energy storage element unit 200. This further improves the safety of the energy storage device 10.

Here, in this embodiment, as described above, the second outer plate portion 335 of the outer plate material 330 is arranged on the outside of the second intermediate plate portion 325, and as shown in FIG. 8, the width of the second intermediate plate portion 325 in the Y-axis direction is smaller than the width of the second outer plate portion 335 in the Y-axis direction. Therefore, when the X-axis direction is defined as the "first direction", each of the multiple storage elements 210 is described as being arranged with the short side surface 212 facing the first direction (X-axis direction) and the long side surfaces 211 of two adjacent storage elements 210 facing each other. Furthermore, when the second intermediate plate portion 325 is arranged in contact with the unit side surface 202 of the storage element unit 200, the storage device 10 is described as follows. The storage device 10 includes an end member 300 having a portion arranged on the side of the storage element unit 200 in the first direction (X-axis direction). The end member 300 includes an intermediate plate material 320 (a second intermediate plate portion 325) and an outer plate material 330 (a second outer plate portion 335) that are arranged to be overlapped in the X-axis direction. The second intermediate plate portion 325 abuts against a side surface (the unit side surface 202 in this example) of the energy storage element unit 200 in the X-axis direction. The second intermediate plate portion 325 is arranged between the energy storage element unit 200 and the second outer plate portion 335, and in a second direction (the Y-axis direction in this example) that intersects with the X-axis direction, the width of the second intermediate plate portion 325 is smaller than the width of the unit side surface 202 of the energy storage element unit 200. The width of the second outer plate portion 335 in the Y-axis direction is larger than the width of the second intermediate plate portion 325 in the Y-axis direction.

Thus, in this embodiment, the end members 300 are disposed on the outside of the short side surfaces 212 of the multiple energy storage elements 210. As a result, when a current collector is disposed inside the energy storage element 210 near the short side surfaces 212, the short side surfaces 212 are protected by the end members 300, reducing the possibility that the current collector will damage the electrode body if an impact is applied to the energy storage device 10. As a result, the safety of the energy storage device 10 is improved.

As shown in Figure 8, there is a space inside the second outer plate portion 335 where the second intermediate plate portion 325 is not arranged. This space is a space where the inward deformation of the second outer plate portion 335 is not hindered by the second intermediate plate portion 325. Therefore, when a large external force acts on the second outer plate portion 335 in the direction of the energy storage element unit 200, the second outer plate portion 335 can absorb the external force by deforming. This reduces the possibility of damage to the energy storage element unit 200. This also improves the safety of the energy storage device 10.

In this embodiment, the end members 300 are arranged on both sides in the Y-axis direction of the energy storage element unit 200. The second outer plate portion 335 of the outer plate material 330 of one of the two end members 300 has a connecting portion 336 that is connected to the second outer plate portion 335 of the outer plate material 330 of the other of the two end members 300.

Thus, in this embodiment, the pair of end members 300 protect both unit end faces 201 in the Y-axis direction of the energy storage element unit 200, and the unit side faces 202 connecting these unit end faces 201. The pair of end members 300 are mechanically connected by connecting the two second outer plate portions 335. Therefore, one end member 300 functions as a member that reinforces the other end member 300. This further improves the safety of the energy storage device 10.

Other Embodiments
The power storage device according to the present invention has been described above based on the embodiment. However, the present invention is not limited to the above embodiment. As long as it does not deviate from the gist of the present invention, various modifications conceived by a person skilled in the art to the above embodiment, or a form constructed by combining multiple components described above, are also included within the scope of the present invention.

When the main focus is on protecting the short side 212 side of the energy storage element 210, the end member 300 may be arranged in a position in which the inner plate material 310 abuts the unit side surface 202. In other words, when the position of the end member 300 is the same as the position shown in FIG. 4, each of the multiple energy storage elements 210 may be arranged side by side with the short side surface 212 facing the first direction (Y-axis direction) and the long side surfaces 211 of two adjacent energy storage elements 210 facing each other. In this case, the unit side surface 202 is an example of a first side surface, and the unit end surface 201 is an example of a second side surface.

Even when this configuration is adopted, the end member 300 has a plurality of overlapping plate materials, so that it can obtain the strength necessary to protect the energy storage element unit 200. A space is formed in the end member 300 to facilitate inward deformation of the plate materials (intermediate plate material 320 and outer plate material 330) that are outside the inner plate material 310.

The number of plate materials constituting the end member 300 is not limited to three. The end member 300 may be formed by stacking at least two plate materials. The end member 300 may be formed of the inner plate material 310 and the intermediate plate material 320. In this case, when viewed from the inner plate material 310, the intermediate plate material 320 is an "outer plate material". The end member 300 may be formed of the inner plate material 310 and the outer plate material 330 joined to the inner plate material 310. When the intermediate plate material 320 is placed in contact with the unit end face 201 or the unit side face 202, the end member 300 may be formed of the intermediate plate material 320 and the outer plate material 330. In this case, when viewed from the outer plate material 330, the intermediate plate material 320 is an "inner plate material". In either case, the end member 300 is made up of multiple stacked plate materials, which provides the strength necessary to protect the energy storage element unit 200 and also forms a space that makes it easy for the outer plate materials to deform inward.

The intermediate plate material 320 may be a flat plate material that does not have the second intermediate plate portion 325. Similarly, the outer plate material 330 may be a flat plate material that does not have the second outer plate portion 335. In this case, if a connecting member that connects the pair of end members 300, such as the connecting plate 380, is arranged, it is possible to restrain and protect the energy storage element unit 200 with the pair of end members 300. As described above, by having a configuration in which the width of the inner plate material 310 is smaller than the width of the unit end face 201, a space that facilitates deformation of the plate material (intermediate plate material 320 or outer plate material 330) outside the inner plate material 310 is secured. In other words, the end member 300 can exhibit an impact absorbing function.

In the embodiment, the bolts 60 and nuts 62 are used to connect the pair of end members 300, but the method of connecting the pair of end members 300 is not limited. The pair of end members 300 may be connected by crimping or welding parts of the pair of end members 300 together.

The materials of the components of the energy storage device 10 are not limited to the materials described in the embodiment. The housing 100 and the end member 300 do not have to be made of metal. The housing 100 and the end member 300 may be formed of a non-metal such as fiber-reinforced plastic. The materials of the multiple plate materials constituting the end member 300 may be different. The materials of the multiple plate materials may be determined based on the strength, rigidity, manufacturing costs, etc. required for the end member 300.

Forms constructed by any combination of the components included in the above embodiments are also included within the scope of the present invention.

The present invention can be applied to a storage device equipped with a storage element such as a lithium ion secondary battery.

REFERENCE SIGNS LIST 10 Energy storage device 200 Energy storage element unit 201 Unit end face 202 Unit side face 210 Energy storage element 211 Long side face 212 Short side face 300 End member 310 Inner plate material 320 Intermediate plate material 321 First intermediate plate portion 325 Second intermediate plate portion 330 Outer plate material 331 First outer plate portion 335 Second outer plate portion 336 Connection portion 500 Other members

Claims (7)

a storage element unit having a plurality of storage elements;
an end member having a portion disposed on a side of the energy storage element unit in the first direction,
the end member includes an inner plate material and an outer plate material arranged to be stacked in the first direction, the inner plate material abutting a first side surface that is a side surface of the energy storage element unit on the first direction side, and being arranged between the energy storage element unit and the outer plate material,
In a second direction intersecting the first direction, a width of the inner plate material is smaller than a width of the first side surface of the energy storage element unit,
The width of the outer plate material in the second direction is larger than the width of the inner plate material in the second direction,
the outer plate materials are disposed on both sides of the energy storage element unit in the first direction,
One of the two skin plate materials has a connecting portion that is connected to the other of the two skin plate materials.
Energy storage device. a width of the inner plate material in a third direction intersecting the first direction and the second direction is smaller than a width of the first side surface of the energy storage element unit;
The inner plate material is arranged within the area of the outline of the first side surface when viewed from the first direction.
The power storage device according to claim 1. Each of the plurality of energy storage elements is arranged in the first direction with a long side surface facing the first direction.
The electricity storage device according to claim 1 or 2. Each of the plurality of storage elements is arranged with a short side surface facing the first direction and with long side surfaces of two adjacent storage elements facing each other.
The electricity storage device according to claim 1 or 2. a storage element unit having a plurality of storage elements;
an end member having a portion disposed on a side of the energy storage element unit in the first direction,
the end member includes an inner plate material and an outer plate material arranged to be stacked in the first direction, the inner plate material abutting a first side surface that is a side surface of the energy storage element unit on the first direction side, and being arranged between the energy storage element unit and the outer plate material,
In a second direction intersecting the first direction, a width of the inner plate material is smaller than a width of the first side surface of the energy storage element unit,
The width of the outer plate material in the second direction is larger than the width of the inner plate material in the second direction,
The end member further includes an intermediate plate member disposed between the inner plate member and the outer plate member,
the intermediate plate member has a first intermediate plate portion facing the inner plate member and a second intermediate plate portion facing a second side surface of the energy storage element unit adjacent to the first side surface,
The outer plate material has a first outer plate portion facing the first intermediate plate portion of the intermediate plate material and a second outer plate portion facing the second intermediate plate portion of the intermediate plate material.
Energy storage device. the end members are disposed on both sides of the energy storage element unit in the first direction,
The second outer plate portion of one of the two end members has a connecting portion that is connected to the second outer plate portion of the other of the two end members.
The power storage device according to claim 5. a storage element unit having a plurality of storage elements;
an end member having a portion disposed on a side of the energy storage element unit in a first direction ;
a housing having a main body portion that accommodates the energy storage element unit and the end member,
The plurality of energy storage elements are arranged side by side in the first direction with their long sides facing the first direction,
the end member includes an inner plate material and an outer plate material arranged to be stacked in the first direction, the inner plate material abutting a first side surface that is a side surface of the energy storage element unit on the first direction side, and being arranged between the energy storage element unit and the outer plate material,
In a second direction that intersects with the first direction and is a longitudinal direction of the long side surface , a width of the inner plate material is smaller than a width of the first side surface of the energy storage element unit,
The width of the outer plate material in the second direction is larger than the width of the inner plate material in the second direction,
The inner plate material is made of metal,
The end member faces the main body portion in the first direction.
Energy storage device.

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