Power storage device

Abstract

To provide a power storage device capable of adjusting the pressure acting on a power storage cell.SOLUTION: A power storage device 1 includes a plurality of power storage cells 100 arranged to be aligned in one direction, a restraining member 300 that restrains the plurality of power storage cells from both sides in the one direction, a liquid medium supplied between power storage cells adjacent to each other and capable of applying pressure on the power storage cells, and a pressure adjusting unit 700 capable of adjusting the pressure applied to the power storage cells from the liquid medium.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electricity storage device. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2016-146298 discloses a battery device including a plurality of battery cells, a cooling body for cooling the battery cells, and a battery case. The battery cells are fixed to the battery case in a state where they are pressed toward each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-146298 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an electricity storage device such as that described in JP 2016-146298 A, there is a need to adjust the pressure acting on each of the multiple electricity storage cells.

[0005] An object of the present disclosure is to provide an electricity storage device capable of adjusting the pressure acting on an electricity storage cell. [Means for solving the problem]

[0006] An energy storage device according to one aspect of the present disclosure includes a plurality of energy storage cells arranged in one direction, a restraint member that restrains the plurality of energy storage cells from both sides in the one direction, a liquid medium supplied between adjacent energy storage cells and capable of applying pressure to the energy storage cells, and a pressure adjustment unit that can adjust the pressure applied to the energy storage cells from the liquid medium. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide an electricity storage device capable of adjusting the pressure acting on an electricity storage cell. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating a schematic configuration of an electricity storage device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a perspective view of a storage cell. [Diagram 3] FIG. [Figure 4] 4 is a cross-sectional view of the electricity storage device taken along a plane perpendicular to one direction and passing through a spacer. FIG. [Diagram 5] 4 is a cross-sectional view of the electricity storage device taken along a plane perpendicular to the height direction. FIG. [Figure 6] FIG. 6 is an enlarged view of the area indicated by the solid line VI in FIG. 5. [Figure 7] FIG. 6 is an enlarged view of the area indicated by solid line VII in FIG. 5. [Figure 8] FIG. 11 is a cross-sectional view illustrating a modified example of the spacer. [Figure 9] FIG. 11 is a cross-sectional view illustrating a modified example of the spacer. [Figure 10] 13 is a cross-sectional view that shows a schematic modification of the case and spacer of the storage cell. FIG. [Figure 11] 13 is a cross-sectional view that shows a schematic modification of the case and spacer of the storage cell. FIG. [Figure 12] 13 is a cross-sectional view showing a schematic modification of the arrangement relationship between the end plate and the case of the electricity storage cell. FIG. [Figure 13] FIG. 11 is a cross-sectional view illustrating a modification of the covering member. [Figure 14] 10A to 10C are cross-sectional views each showing a schematic configuration of a modified example of the method for manufacturing an electricity storage device. [Figure 15] 10A to 10C are cross-sectional views each showing a schematic configuration of a modified example of the method for manufacturing an electricity storage device. [Figure 16] 10A to 10C are cross-sectional views each showing a schematic configuration of a modified example of the method for manufacturing an electricity storage device. [Figure 17] FIG. 4 is a perspective view illustrating a schematic configuration of an electricity storage device according to a second embodiment of the present disclosure. [Figure 18] 4 is a cross-sectional view of the electricity storage device taken along a plane perpendicular to one direction and passing through a spacer. FIG. [Figure 19] FIG. 11 is a cross-sectional view illustrating a modified example of the gas vent member. [Figure 20] FIG. 11 is a cross-sectional view illustrating a modified example of the gas vent member. [Figure 21] 11 is a cross-sectional view illustrating a schematic configuration of an electricity storage device according to a third embodiment of the present disclosure. FIG. [Figure 22] 13 is a perspective view of a frame of a spacer in an electricity storage device according to a third embodiment. [Figure 23] FIG. 11 is a cross-sectional view that illustrates a schematic configuration of a modification of the electricity storage device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0010] (First embodiment) Fig. 1 is a perspective view that shows a schematic configuration of an electricity storage device according to a first embodiment of the present disclosure. Fig. 2 is a perspective view of an electricity storage cell. Fig. 3 is a perspective view of a spacer. The electricity storage device 1 is mounted on, for example, a vehicle.

[0011] 1 to 3, the energy storage device 1 includes a plurality of energy storage cells 100, a spacer 200, a binding member 300, a covering member 400, a liquid medium 500, a liquid flow path forming member 600, and a pressure adjusting section 700. The number of energy storage cells 100 and the number of spacers 200 included in the energy storage device 1 are not particularly limited.

[0012] The multiple storage cells 100 are arranged in one direction. For example, a lithium ion battery is used as each storage cell 100. As shown in FIG. 2, each storage cell 100 has a case 110 and a pair of external terminals 120.

[0013] The case 110 houses an electrode body and the like (not shown). The case 110 is formed in a rectangular parallelepiped shape. The case 110 is formed flat. That is, the case 110 has two first side surfaces 112 having a relatively large area, and two second side surfaces 114 having an area smaller than the area of ​​the first side surfaces 112. The multiple storage cells 100 are arranged such that the first side surfaces 112 of the cases 110 face each other. Each of the first side surfaces 112 is formed flat.

[0014] Each external terminal 120 protrudes from an outer side surface of the case 110. In this embodiment, the pair of external terminals 120 protrudes from the second side surface 114. One of the pair of external terminals 120 is a positive terminal, and the other is a negative terminal.

[0015] The spacer 200 forms a holding space S for holding the liquid medium 500 between the adjacent energy storage cells 100. As shown in FIG. 3, the spacer 200 has a plurality of frame members 210. Each frame member 210 is disposed between the adjacent energy storage cells 100, and each frame member 210 defines a holding space S between the adjacent energy storage cells 100. Each frame member 210 is made of resin. The frame member 210 has an upper gap forming portion 211, a lower gap forming portion 212, and a connecting portion 213.

[0016] The upper gap forming portion 211 is disposed between the upper portions of the adjacent cases 110. The upper gap forming portion 211 has a shape extending in a width direction perpendicular to both the one direction and the height direction.

[0017] The lower gap forming portion 212 is disposed between the lower parts of the adjacent cases 110. The lower gap forming portion 212 has a shape extending in the width direction.

[0018] The connecting portion 213 connects the upper gap forming portion 211 and the lower gap forming portion 212. More specifically, the connecting portion 213 connects an end portion of the upper gap forming portion 211 on a side closer to the external terminal 120 in the width direction (the right side in FIG. 4) to an end portion of the lower gap forming portion 212 on a side closer to the external terminal 120 in the width direction (the right side in FIG. 4). The connecting portion 213 has a shape extending in the height direction.

[0019] The frame member 210 opens in the width direction in a direction opposite to the direction in which the external terminals 120 protrude from the case 110 (to the left in FIG. 4). In other words, the frame member 210 has an opening 200a that opens to the holding space S. The frame member 210 may have a shape that opens in a direction different from the above direction (for example, upward in FIG. 4).

[0020] The restraining member 300 restrains the plurality of storage cells from both sides in the one direction. The restraining member 300 has a pair of end plates 310 and a restraining band 320.

[0021] The pair of end plates 310 are disposed in one direction at positions sandwiching the plurality of energy storage cells 100. Each end plate 310 has a shape extending in the width direction.

[0022] The covering member 400 covers the periphery of the spacer 200. The covering member 400 is made of an insulating material (resin in this embodiment). The covering member 400 prevents the liquid medium 500 from leaking out of the spacer 200 from the holding space S. As shown in FIG. 4, the covering member 400 is formed by molding resin around the spacer 200. In this embodiment, the covering member 400 covers the cases 110 of the energy storage cells 100 and the spacer 200 together. The covering member 400 covers the base ends of the external terminals 120 so that the tip ends of the external terminals 120 are exposed.

[0023] The restraint bands 320 restrain each end plate from both sides in one direction so that the pair of end plates 310 press the multiple energy storage cells 100 inward in one direction. The restraint bands 320 are wrapped around a unit including the pair of end plates 310 and the covering member 400. The restraint bands 320 are preferably made of FRP containing continuous fibers.

[0024] The electricity storage device 1 of this embodiment has another band 330 wrapped around the covering member 400 in a plane perpendicular to the one direction.

[0025] The liquid medium 500 is supplied between the adjacent energy storage cells 100. The liquid medium 500 is supplied to the holding space S. The liquid medium 500 can apply pressure to the energy storage cells 100 as shown by the arrows in FIG. 6. More specifically, the liquid medium 500 applies pressure in one outward direction to the first side surfaces 112 facing each other. In this embodiment, oil is used as the liquid medium 500. Note that the liquid medium 500 is not shown in FIG. 4.

[0026] The liquid flow path forming member 600 forms a flow path for supplying the liquid medium 500 to each holding space S. As shown in Fig. 4, the liquid flow path forming member 600 is disposed so as to contact the second side surface 114 of the case 110 opposite to the side on which the external terminals 120 are located. The liquid flow path forming member 600 has a shape extending in one direction so as to contact the second side surfaces 114 of all the energy storage cells 100. The liquid flow path forming member 600 closes the openings 200a of the spacer 200.

[0027] As shown in Fig. 4, the liquid flow path forming member 600 has a liquid flow path 600a that communicates with the opening 200a of the spacer 200. The liquid flow path 600a is formed in a portion on the inner side (right side in Fig. 4) of the liquid flow path forming member 600 in the width direction, in other words, in a portion of the liquid flow path forming member 600 that faces the opening 200a in the width direction. As shown in Figs. 1, 5 and 7, a liquid pipe 650 is connected to the upstream end of the liquid flow path 600a.

[0028] The pressure adjusting unit 700 is capable of adjusting the pressure acting on the energy storage cell 100 from the liquid medium 500. The pressure adjusting unit 700 is connected to the liquid pipe 650. In this embodiment, the pressure adjusting unit 700 is formed of a cylinder.

[0029] The liquid medium 500 pushed out from the pressure adjustment unit 700 is supplied to each holding space S through the liquid pipe 650 and the liquid flow path 600a. The liquid medium 500 supplied to the holding space S applies pressure in one outward direction to each of the first side surfaces 112 of a pair of adjacent energy storage cells 100.

[0030] Next, a method for manufacturing the electricity storage device 1 will be described.

[0031] First, the energy storage cells 100 and the frame members 210 are arranged so as to be alternately aligned. Then, a pair of end plates 310 are arranged at positions sandwiching the multiple energy storage cells 100 from both sides in one direction, and a liquid flow path forming member 600 is arranged so as to contact the second side surface 114 of each case 110.

[0032] In this state, the plurality of power storage cells 100, the spacers 200 and the liquid flow path forming member 600 are molded with resin to form the covering member 400.

[0033] Thereafter, the restraining band 320 is formed around the unit integrated by the covering member 400 by a filament winding method.

[0034] Next, the liquid medium 500 is supplied to each holding space S through the liquid pipe 650 and the liquid flow path 600a. At this time, the pressure acting on the energy storage cell 100 from the liquid medium 500 is adjusted by the pressure adjustment unit 700 so that an optimal pressure acts on the first side surface 112 of the case 110 depending on the usage status of the energy storage device 1.

[0035] As described above, in the energy storage device 1 of this embodiment, the liquid medium 500 is supplied between adjacent energy storage cells 100, so that the pressure acting from the liquid medium 500 on the energy storage cells 100 can be adjusted by the pressure adjustment section 700.

[0036] In addition, since the member restrained by the restraining member 300 undergoes creep deformation, the restraining force by the restraining member 300 is set taking into consideration the amount of creep deformation, but in this case, there is a concern that the restraining force may be excessive in the early stages of use. In contrast, in this embodiment, the pressure acting on each energy storage cell 100 can be adjusted by the pressure adjustment unit 700, so that the restraining force is prevented from becoming excessive.

[0037] Furthermore, since the covering member 400 covers the periphery of the spacer 200, leakage of the liquid medium 500 from the holding space S to the outside of the spacer 200 is suppressed.

[0038] Furthermore, since the liquid flow path 600a and the opening 200a of the spacer 200 are formed on the side of the case 110 opposite the side on which the external terminal 120 is located, short-circuiting between the power storage cells 100 due to the liquid medium 500 is suppressed.

[0039] Modifications to the above embodiment will now be described.

[0040] (First Modification) 8, the frame member 210 may have a first notch 201 and a second notch 202. The first notch 201 is formed in a portion of the frame member 210 that contacts the covering member 400. The second notch 202 is formed in a portion of the frame member 210 that contacts the liquid medium 500.

[0041] By forming first cuts 201, resin enters first cuts 201 when covering member 400 is formed, and a force acts on frame member 210 as shown by the arrows in Fig. 8. This increases the adhesion between frame member 210 and case 110.

[0042] Similarly, when the liquid medium 500 supplied to the holding space S enters the second notches 202, a force acts on the frame member 210 as shown by the arrows in FIG. 8, thereby increasing the adhesion between the frame member 210 and the case 110.

[0043] (Second Modification) As shown in FIG. 9, the frame member 210 may be omitted, and cuts 402 may be formed in the covering member 400 at locations located between the adjacent energy storage cells 100.

[0044] (Third Modification) 10, a convex portion 110a may be formed on the first side surface 112 of the case 110, and a concave portion 210a that engages with the convex portion 110a may be formed on the frame member 210. In this embodiment, the adhesion between the frame member 210 and the case 110 is enhanced by the pressure acting on the frame member 210 from the resin when forming the covering member 400, or the pressure acting on the frame member 210 from the liquid medium 500 supplied to the holding space S.

[0045] (Fourth Modification) As shown in FIG. 11, a recess 110b may be formed on the first side surface 112 of the case 110, and a protrusion 210b that engages with the recess 110b may be formed on the frame member 210.

[0046] (Fifth Modification) 12 , a structure may be used in which the energy storage cells 100 arranged on the outermost side in one direction are arranged so as to be in direct contact with the end plate 310, and the liquid medium 500 is not supplied between the energy storage cells 100 and the end plate 310. In this case, the end plate 310 does not need to be covered with the covering member 400.

[0047] (Sixth Modification) 13, the end plate 310 may be covered with a covering member 400. In this case, the liquid medium 500 may be supplied between the end plate 310 and the energy storage cell 100 arranged on the outermost side in one direction, or the liquid medium 500 may not be supplied between the energy storage cell 100 and the end plate 310.

[0048] (Seventh Modification) As shown in Fig. 14, a restraining band 320 that has been hardened before being wrapped around the integrated unit by the covering member 400 may be assembled to the unit, and then, as shown in Fig. 15, an intermediate member 312 may be inserted between the restraining band 320 and the end plate 310 to restrain the multiple energy storage cells 100. In this example, the end plate 310, the intermediate member 312 and the restraining band 320 constitute the restraining member 300.

[0049] (Eighth Modification) As shown in FIG. 16, in order to suppress heat input to the energy storage cells 100 when the covering member 400 is formed (when molding with resin), a first insulating material 11 may be placed around each energy storage cell 100 before the covering member 400 is formed.

[0050] Furthermore, in order to suppress heat input to the energy storage cells 100 when the restraint bands 320 are formed (when the restraint bands 320 are thermally cured in the filament winding method), a second insulating material 12 may be disposed around the covering member 400 before the restraint bands 320 are wound.

[0051] Second embodiment Next, an electricity storage device 1 according to a second embodiment of the present disclosure will be described with reference to Figs. 17 and 18. Fig. 17 is a perspective view that shows a schematic configuration of an electricity storage device according to a second embodiment of the present disclosure. Fig. 18 is a cross-sectional view of the electricity storage device in a plane that is perpendicular to one direction and passes through a spacer. Note that the liquid medium 500 is omitted from Fig. 18. In the second embodiment, only the parts that differ from the first embodiment will be described, and the same structure, action, and effect as those of the first embodiment will not be described repeatedly.

[0052] The electricity storage device 1 of this embodiment further includes a gas flow path forming member 800, a gas pipe 850, and a gas vent valve 860.

[0053] The gas flow passage forming member 800 forms a flow passage for extracting gas (air, etc.) from the holding space S. The gas flow passage forming member 800 is connected to each of the frame members 210.

[0054] As shown in FIG. 18, a gas flow passage forming member 800 has a plurality of gas vent portions 810 and a junction portion 820.

[0055] Each gas vent portion 810 is connected to the frame member 210. In this embodiment, the gas vent portion 810 is connected to the connecting portion 213. More specifically, a through hole that opens the holding space S is formed in the connecting portion 213, and the gas vent portion 810 is fixed to the connecting portion 213 in a state where it is inserted into the through hole. The gas vent portion 810 has a shape that extends outward in the width direction from the connecting portion 213. The gas vent portion 810 has a gas flow path 800a that communicates with the holding space S.

[0056] The junction 820 is a portion where the gases released from each of the gas venting sections 810 join together. The junction 820 is connected to each of the gas venting sections 810. The junction 820 is formed on the outer side of the case 110 in the width direction, and has a shape that extends in one direction.

[0057] The gas pipe 850 is connected to the downstream end of the gas flow passage 800a.

[0058] The gas vent valve 860 is provided in the gas pipe 850. The gas vent valve 860, for example, allows the passage of gas and prohibits the passage of the liquid medium 500.

[0059] In the electricity storage device 1 of this embodiment, when the liquid medium 500 is supplied to the retention space S, the gas present in the retention space S is extracted through the gas flow path 800a to the gas pipe 850. This prevents the gas from remaining in the retention space S and the associated unevenness in the pressure distribution acting on each of the electricity storage cells 100.

[0060] As shown in FIG. 19, the junction 820 may protrude further outside the covering member 400.

[0061] As shown in FIG. 20, the gas vent portion 810 may be connected to the upper gap forming portion 211 of the frame member 210, and the junction portion 820 may protrude from the upper surface of the case 110.

[0062] Third embodiment Next, a power storage device 1 according to a third embodiment of the present disclosure will be described with reference to Figs. 21 and 22. Fig. 21 is a cross-sectional view that shows a schematic configuration of the power storage device according to the third embodiment of the present disclosure. Fig. 22 is a perspective view of a frame of a spacer in the power storage device according to the third embodiment. Note that the liquid medium 500 is omitted from Fig. 21. In the third embodiment, only the parts that are different from the first embodiment will be described, and the same structure, action, and effect as those of the first embodiment will not be described repeatedly.

[0063] In this embodiment, the spacer 200 includes a frame 215 and a covering sheet 220 .

[0064] The frame body 215 is capable of collectively holding a plurality of energy storage cells 100. As shown in Fig. 22, the frame body 215 has a plurality of insertion holes 215a. Each of the insertion holes 215a is formed to a size that allows an energy storage cell 100 to be inserted therethrough. The plurality of insertion holes 215a are formed to be aligned in one direction.

[0065] The covering sheet 220 covers the multiple storage cells 100 collectively so as to form a holding space S together with the frame 215. The covering sheet 220 covers at least the upper and lower surfaces of each case 110. In this embodiment, the covering sheet 220 is wrapped around the upper surface of each case 110, the outer first side surface 112 of the case 110 of the storage cell 100 arranged at one end in one direction, the lower surface of each case 110, and the outer first side surface 112 of the case 110 of the storage cell 100 arranged at the other end in one direction, thereby collectively covering the multiple storage cells 100. The covering sheet 220 is preferably made of an insulating material.

[0066] In this embodiment, as shown in Fig. 23, the energy storage device 1 may further include a pair of plate members 230 connected to a surface of the covering sheet 220 via an adhesive member 240. One plate member 230 is connected to the covering sheet 220 covering the upper surface of each case 110 via an adhesive member 240, and the other plate member 230 is connected to the covering sheet 220 covering the lower surface of each case 110 via an adhesive member 240. Each plate member 230 has a shape extending in one direction. Each plate member 230 may have a flow path 230a through which a cooling medium capable of cooling the energy storage cells 100 flows.

[0067] In the example shown in FIG. 23, the covering member 400 covers the outer region of the frame 215 in the width direction and the liquid flow path forming member 600.

[0068] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0069] The energy storage device in the above embodiment includes a plurality of energy storage cells arranged in a line in one direction, a restraint member that restrains the plurality of energy storage cells from both sides in the one direction, a liquid medium that is supplied between adjacent energy storage cells and is capable of applying pressure to the energy storage cells, and a pressure adjustment unit that is capable of adjusting the pressure acting from the liquid medium on the energy storage cells.

[0070] In this electricity storage device, a liquid medium is supplied between adjacent electricity storage cells, and the pressure adjusting section can adjust the pressure acting on the electricity storage cells from the liquid medium.

[0071] It is also preferable that the electricity storage device further includes a spacer that forms a holding space for holding the liquid medium between the electricity storage cells adjacent to each other.

[0072] The energy storage cell may have a case and a pair of external terminals protruding from the case in a direction perpendicular to the one direction. In this case, the spacer may have a plurality of frame members each disposed between adjacent energy storage cells and defining the holding space, each of the frame members having an opening that opens the holding space in a direction different from a direction in which the pair of external terminals protrude from the case, and the liquid medium may be supplied to the holding space from the opening.

[0073] It is also preferable that each of the frame members has a notch formed in a portion of the frame member that comes into contact with the liquid medium.

[0074] The spacer may also have a frame capable of collectively holding the plurality of energy storage cells, and a cover sheet that collectively covers the plurality of energy storage cells so as to form the holding space together with the frame.

[0075] In addition, it is preferable that the electricity storage device further includes a covering member that covers a periphery of the spacer.

[0076] This prevents the liquid medium from leaking from the holding space, thereby preventing short circuits between the electricity storage cells.

[0077] It is preferable that the electricity storage device further includes a liquid flow path forming member that is disposed so as to be in contact with the plurality of electricity storage cells and has a liquid flow path for introducing the liquid medium into the holding space.

[0078] In addition, it is preferable that the power storage device further includes a gas flow passage forming member connected to the spacer and having a gas flow passage for extracting gas from the holding space.

[0079] In this way, the gas present in the holding space is drawn into the gas flow path when the liquid medium is supplied to the holding space, thereby preventing the gas from remaining in the holding space and the associated unevenness in the pressure distribution acting on each storage cell.

[0080] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0081] 1 Energy storage device, 100 Energy storage cell, 110 Case, 112 First side, 114 Second side, 120 External terminal, 200 Spacer, 200a Opening, 210 Frame member, 211 Upper gap forming portion, 212 Lower gap forming portion, 213 Connection portion, 215 Frame body, 215a Insertion hole, 220 Covering sheet, 300 Restraint member, 310 End plate, 320 Restraint band, 400 Covering member, 500 Liquid medium, 600 Liquid flow path forming member, 600a Liquid flow path, 650 Liquid pipe, 700 Pressure adjustment portion, 800 Gas flow path forming member, 800a Gas flow path, 810 Gas vent portion, 820 Junction portion, 850 Gas pipe, 860 Gas vent valve, S Holding space.

Claims

1. A plurality of storage cells arranged in one direction; A restraining member that restrains the plurality of storage cells from both sides in the one direction; a liquid medium that is supplied between the adjacent energy storage cells and is capable of applying pressure to the energy storage cells; a pressure adjusting unit capable of adjusting a pressure acting from the liquid medium on the electricity storage cell; a spacer that forms a holding space for holding the liquid medium between the adjacent storage cells; a gas flow passage forming member connected to the spacer and having a gas flow passage for extracting gas from the holding space.

2. The storage cell is Case and a pair of external terminals protruding from the case in a direction perpendicular to the one direction, the spacer includes a plurality of frame members each disposed between adjacent ones of the storage cells and defining the holding space; each of the plurality of frame members has an opening that opens the holding space in a direction different from a direction in which the pair of external terminals protrude from the case; The electricity storage device according to claim 1 , wherein the liquid medium is supplied to the holding space through the opening.

3. The power storage device according to claim 2 , wherein each of the frame members has a notch formed in a portion of the frame member that comes into contact with the liquid medium.

4. The spacer is A frame capable of collectively holding the plurality of storage cells; The electricity storage device according to claim 1 , further comprising: a covering sheet that collectively covers the plurality of electricity storage cells so as to form the holding space together with the frame body.

5. The power storage device according to claim 1 , further comprising a covering member that covers a periphery of the spacer.

6. The electricity storage device according to claim 1 , further comprising a liquid flow path forming member disposed in contact with the plurality of electricity storage cells, the liquid flow path forming member having a liquid flow path for introducing the liquid medium into the holding space.

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