Energy storage device

Abstract

To provide a power storage device with which, while suppressing liquid junctions, it is possible to suppress an increase in device size.SOLUTION: A power storage device 1 comprises: a power storage module 4 that has an electrode laminate 11 and a second seal part 12; a pair of restraint plates 8 that are arranged so as to sandwich the electrode laminate 11 in a first direction D1; and a plurality of fasteners 9 and struts 10 that are arranged outside of the second seal part 12 as seen from the first direction D1 and that fasten the pair of restraint plates 8 so as to restrain the electrode laminate 11. An eaves part 60 is formed on an outer peripheral surface 12s of the second seal part 12, the eaves part having an upper face 61s that is inclined so as to separate progressively from the outer peripheral surface 12s as it goes downward. A notch 70 is formed in a portion of the eaves part 60 that faces each of the struts 10. A wall part 72 is formed at an edge 71 of the notch 70, the wall part that projects from the edge 71 and extends along the edge 71.SELECTED DRAWING: Figure 6

Description

Technical Field

[0005]

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] Patent Document 1 describes a power storage device. This power storage device includes a restraint, a plurality of power storage units, a plurality of current collector plates, and an insulating plate. The restraint includes a top plate, a bottom plate, and columns, and a plurality of power storage units, a plurality of current collector plates, and an insulating plate are arranged between the top plate and the bottom plate. Further, the upper end portion of the column is fixed to the top plate, and the lower end portion of the column is fixed to the bottom plate. The power storage unit includes a seal member and a flange formed on the long wall portion of the seal member. The flange includes an inclined portion having an inclined surface that extends downward as it moves away from the outer peripheral surface of the long wall portion in the horizontal direction. The columns of the restraint extend along the long wall portion in the stacking direction of the power storage units.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power storage device described in Patent Document 1 above, the liquid accumulated in the gap between certain power storage units drips from the gap onto the flange and moves on the inclined surface of the flange, so that it is separated from the gap between other power storage units in the horizontal direction. Thereby, it is intended to suppress the liquid from entering the gap between other power storage units. As a result, a short circuit (liquid bridge) due to the liquid can be suppressed.

[0005] In the energy storage device described in Patent Document 1 above, the column of the restraint device must be positioned at a predetermined distance from the canopy that extends outward from the sealing member. As a result, the energy storage device becomes larger by the amount of the canopy compared to a case without a canopy. On the other hand, when mounting an energy storage device on a vehicle or the like, it is desirable to suppress the increase in size of the energy storage device.

[0006] The purpose of this disclosure is to provide an energy storage device that can suppress liquid junctions while keeping the size of the device down. [Means for solving the problem]

[0007] The energy storage device according to this disclosure comprises an electrode stack including a plurality of electrodes stacked along a first direction, and an energy storage module having a seal portion provided around the electrode stack to seal the spaces between the electrodes, a pair of restraint plates arranged to sandwich the electrode stack in the first direction, and a plurality of connecting members arranged outside the seal portion when viewed from the first direction, extending along the first direction and restraining the electrode stack by connecting the pair of restraint plates along the first direction, wherein the outer circumferential surface of the seal portion along the first direction has a canopy portion having an upper surface that slopes away from the outer circumferential surface as it goes downward in the first direction, and notches are formed in the portions of the canopy portion facing each of the connecting members so as to be spaced away from the connecting members, and wall portions are formed at the edges of the notches that protrude upward in the first direction from the edges and extend along the edges.

[0008] In this energy storage device, a sealing portion is provided around the electrode stack, and a canopy portion is formed on the outer surface of the sealing portion, with an upper surface that slopes downward so as it moves away from the outer surface. Therefore, if liquid adheres to the outer surface of the sealing portion, the liquid moves downward along the upper surface of the canopy portion, separating it from the outer surface and falling off from the upper surface. Thus, short circuits caused by the liquid are suppressed.

[0009] On the other hand, in this energy storage device, the connecting member for restraining the electrode stack is positioned outside the seal portion. Furthermore, a notch is provided in the portion of the eaves portion that faces the connecting member, so as to be spaced away from the connecting member. As a result, compared to a case where there is no notch in the eaves portion, it is possible to position the connecting member closer to the outer surface of the seal portion while maintaining the distance between the connecting member and the eaves portion. Thus, the size of the device is suppressed.

[0010] Furthermore, in this energy storage device, a wall portion is formed along the edge of the notch, projecting upward in the first direction and extending along the edge. Therefore, the wall portion prevents liquid adhering to the outer surface of the seal portion at the position corresponding to the notch from entering the gap between the notch and the connecting member. In other words, even when a notch is provided as described above, liquid junctions caused by the notch are suppressed. As described above, this energy storage device makes it possible to suppress liquid junctions while keeping the size of the device down.

[0011] In the energy storage device according to this disclosure, the wall portion may extend along the entire edge so as to reach the tip of the eaves portion. In this case, liquid adhering to the outer surface of the seal portion at the position corresponding to the notch is reliably guided to the upper surface of the eaves portion by the wall portion provided at the edge of the notch. Therefore, liquid junctions can be suppressed more reliably.

[0012] In the energy storage device according to this disclosure, the upper end surface of the wall in the first direction may be flush with the upper end surface of the seal portion, which is the upper end surface in the first direction of the portion corresponding to the notch in the seal portion, or it may be located above the upper end surface of the seal portion in the first direction. In this case, it is suppressed that liquid moving from the upper end surface of the seal portion toward the outer circumferential surface will pass over the wall portion and enter the gap between the notch and the connecting member.

[0013] In the energy storage device according to this disclosure, the shape of the outer edge of the portion of the connecting member facing the outer circumferential surface is arc-shaped when viewed from a first direction, and the shape of the notch edge and the shape of the wall portion may be arc-shaped that is recessed in accordance with the shape of the outer edge of the connecting member when viewed from a first direction. In this case, while ensuring the distance between the wall portion and the connecting member, it is possible to increase the distance between the outer circumferential surface of the sealing portion at the end of the wall portion (end of the arc) and facilitate the flow of liquid toward the overhang portion.

[0014] In the energy storage device according to this disclosure, the wall portion may be inclined so that it moves away from the outer surface as it extends upward in the first direction. In this case, compared to the case where the wall portion extends parallel to the first direction, the surface area of ​​the wall portion as viewed from the first direction is increased, making it easier to flow more liquid towards the overhang portion. In addition, in this case, for example, when the seal portion and the wall portion are formed by injection molding, the wall portion becomes easier to demold, and manufacturing is simplified. [Effects of the Invention]

[0015] According to this disclosure, it is possible to provide an energy storage device that can suppress liquid junctions while keeping the size of the device down. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic cross-sectional view showing a cross-section of a power storage device according to one embodiment, including the first and second directions. [Figure 2] Figure 2 is a schematic cross-sectional view showing a cross-section of a power storage device according to one embodiment, including the first and third directions. [Figure 3] Figure 3 is a schematic cross-sectional view showing the energy storage module shown in Figures 1 and 2. [Figure 4] Figure 4 is a plan view of the energy storage module shown in Figures 1-3. [Figure 5] Figure 5 is an enlarged view of section P1 shown in Figure 4. [Figure 6] Figure 6 is an enlarged view of the portion P2 shown in Figure 4. [Figure 7] Figure 7 is a schematic cross-sectional view of portion P2 shown in Figure 4.

Best Mode for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the power storage device will be described with reference to the drawings. In the description of each figure, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions may be omitted. Also, each figure shows an orthogonal coordinate system composed of a first axis defining a first direction D1, a second axis defining a second direction D2, and a third axis defining a third direction D3. As an example, the first direction D1 is the vertical direction, and the second direction D2 and the third direction D3 are two horizontal directions intersecting each other.

[0018] FIG. 1 is a schematic cross-sectional view showing a cross section including the first direction and the second direction of the power storage device according to an embodiment. FIG. 2 is a schematic cross-sectional view showing a cross section including the first direction and the third direction of the power storage device according to an embodiment. The power storage device 1 shown in FIGS. 1 and 2 can be used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 includes a module laminate 2 including a plurality of power storage modules 4 laminated along the first direction D1, and a restraint member 3 that applies a restraint load along the first direction D1 to the module laminate 2.

[0019] The module laminate 2 includes a plurality (here, three) of power storage modules 4 and a plurality (here, two) of conductive plates 5. The power storage module 4 is, for example, a bipolar battery and has a rectangular shape when viewed from the first direction D1. More specifically, the power storage module 4 has a rectangular shape having a long side and a short side when viewed from the first direction D1. The power storage module 4 is, for example, a secondary battery such as a nickel-hydrogen battery or a lithium-ion battery, or an electric double layer capacitor. In the following description, a nickel-hydrogen secondary battery will be exemplified.

[0020] In the module laminate 2, a conductive plate 5 is interposed between adjacent power storage modules 4 along the first direction D1. As a result, a plurality of power storage modules 4 are electrically connected via the conductive plate 5. More specifically, each power storage module 4 includes a positive electrode terminal surface on one end face in the first direction D1 and a negative electrode terminal surface on the other end face in the first direction D1, and a plurality of power storage modules 4 laminated via the conductive plate 5 are connected in series. Outside the power storage module 4 located at one end of the module laminate 2 in the first direction D1, a current collecting plate 6 from which a positive electrode terminal 6a is drawn out is disposed and electrically connected to the power storage module 4. Further, outside the power storage module 4 located at the other end of the module laminate 2 in the first direction D1, a current collecting plate 7 from which a negative electrode terminal 7a is drawn out is disposed and electrically connected to the power storage module 4. By using these positive electrode terminal 6a and negative electrode terminal 7a, charge and discharge of the power storage device 1 are performed.

[0021] Inside the conductive plate 5, a plurality of flow paths 5a for allowing a refrigerant such as air to flow are provided. The flow paths 5a extend along a direction (here, the third direction D3) that intersects (is orthogonal to) the first direction D1 and the drawing-out directions of the positive electrode terminal 6a and the negative electrode terminal 7a, respectively. The conductive plate 5 has a function as a heat radiating member that radiates heat generated in the power storage module 4 by allowing a refrigerant to flow through these flow paths 5a, in addition to the function as a connecting member that electrically connects the power storage modules 4 to each other.

[0022] The restraining member 3 includes a pair of restraining plates 8 that sandwich the module stack 2 in the stacking direction, a plurality of fasteners (connecting members) 9 such as bolts that connect the restraining plates 8 together, and a support column (connecting member) 10 that houses the main body of the fasteners 9 (for example, the shaft of a bolt). The restraining plate 8 is a rectangular metal plate having an area slightly larger than the area of ​​the energy storage module 4 and conductive plate 5 as viewed from the first direction. The restraining plate 8 is rectangular in shape with a long side and a short side as viewed from the first direction D1. A plate-shaped insulating member F is provided on the inner surface of the restraining plate 8 (the surface facing the module stack 2). That is, a current collector plate 6 or current collector plate 7 and the insulating member F are interposed between the module stack 2 and the restraining plate 8. This provides insulation between the restraining plate 8 and the module stack 2 (current collector plates 6, 7).

[0023] An insertion hole 8a is provided on the edge of one restraint plate 8 at a position outside the module stack 2 when viewed from the first direction D1, and a screw hole 8b is provided on the edge of the other restraint plate 8 at a position opposite to the insertion hole 8a. The fastener 9 is passed through the insertion hole 8a of one restraint plate 8 towards the screw hole 8b of the other restraint plate 8 and screwed into the screw hole 8b of the other restraint plate 8. As a result, the energy storage module 4 and the conductive plate 5 are sandwiched by the restraint plates 8 and unitized as a module stack 2, and a restraining load is applied to the module stack 2 along the first direction.

[0024] Thus, the fastener 9 is positioned on the outside of the module stack 2 (the second seal portion 12 described later), extends along the first direction D1, and restrains the module stack 2 (the electrode stack 11 described later) by fastening a pair of restraint plates 8 together along the first direction D1. The support column 10 is interposed between the pair of restraint plates 8 and extends along the first direction D1 together with the fastener 9. The support column 10 defines the restraining force on the module stack 2 by defining the distance between the pair of restraint plates 8 in the first direction D1.

[0025] In the energy storage device 1, multiple connecting members, each consisting of one fastener 9 and one support column 10 housing the fastener 9, are arranged along the long side of the restraint plate 8 when viewed from the first direction D1. Furthermore, when viewed from the first direction D1, the connecting members face each other in a direction along the short side of the restraint plate 8. The closer these opposing connecting members are to each other, the more uniformly a restraining load can be applied to the energy storage module 4 via the restraint plate 8.

[0026] Figure 3 is a schematic cross-sectional view showing the configuration of the energy storage module shown in Figures 1 and 2. As shown in Figure 3, the energy storage module 4 comprises an electrode stack 11 and a second resin seal portion (seal portion) 12 that seals the electrode stack 11. The electrode stack 11 includes a plurality of electrodes (a plurality of bipolar electrodes 14, a negative terminal electrode 18, and a positive terminal electrode 19) stacked along a first direction D1 via a separator 13. Here, the stacking direction of the electrodes coincides with the stacking direction of the energy storage module 4.

[0027] The bipolar electrode 14 includes an electrode plate 15 with a first surface 15a and a second surface 15b opposite to the first surface 15a, a positive electrode active material layer 16 provided on the first surface 15a, and a negative electrode active material layer 17 provided on the second surface 15b. In the electrode stack 11, the positive electrode active material layer 16 of one bipolar electrode 14 faces the negative electrode active material layer 17 of another bipolar electrode 14 adjacent in the first direction D1, separated by a separator 13. In the electrode stack 11, the negative electrode active material layer 17 of one bipolar electrode 14 faces the positive electrode active material layer 16 of yet another bipolar electrode 14 adjacent in the first direction D1, separated by a separator 13.

[0028] The negative electrode terminal electrode 18 includes an electrode plate 15 and a negative electrode active material layer 17 provided on the second surface 15b of the electrode plate 15. The first surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18 does not have an active material layer. The negative electrode terminal electrode 18 is positioned at one end of the electrode stack 11 in the first direction D1 such that its second surface 15b faces the inside of the electrode stack 11 (towards the center in the first direction D1). The negative electrode active material layer 17 of the negative electrode terminal electrode 18 faces the positive electrode active material layer 16 of the bipolar electrode 14 at one end of the first direction D1 via a separator 13.

[0029] The positive terminal electrode 19 includes an electrode plate 15 and a positive electrode active material layer 16 provided on the first surface 15a of the electrode plate 15. The second surface 15b of the electrode plate 15 of the positive terminal electrode 19 does not have an active material layer. The positive terminal electrode 19 is positioned at the other end of the electrode stack 11 in the first direction D1 such that its first surface 15a is on the inside of the electrode stack 11. The positive electrode active material layer 16 of the positive terminal electrode 19 faces the negative electrode active material layer 17 of the bipolar electrode 14 at the other end in the first direction D, via a separator 13.

[0030] The first surface 15a of the electrode plate 15 of the negative terminal electrode 18 is the surface facing the outside of the electrode stack 11. A conductive plate 5 is electrically connected to the first surface 15a of the negative terminal electrode 18 via a metal plate 50, which will be described later. The second surface 15b of the electrode plate 15 of the positive terminal electrode 19 is also the surface facing the outside of the electrode stack 11. Another conductive plate 5 is electrically connected to the second surface 15b of the positive terminal electrode 19 via a metal plate 50, which will be described later.

[0031] The electrode plate 15 is made of a metal such as nickel or nickel-plated steel. For example, the electrode plate 15 is a rectangular metal foil made of nickel. The peripheral edge 15c of the electrode plate 15 (the peripheral edge of the bipolar electrode 14, the negative electrode terminal electrode 18, and the positive electrode terminal electrode 19) is rectangular in shape and is a region where the positive electrode active material layer 16 and the negative electrode active material layer 17 are not formed. Examples of positive electrode active materials that constitute the positive electrode active material layer 16 include nickel hydroxide. Examples of negative electrode active materials that constitute the negative electrode active material layer 17 include hydrogen storage alloys.

[0032] The separator 13 is formed, for example, in the form of a sheet. Examples of the separator 13 include porous films made of polyolefin resins such as polyethylene (PE) and polypropylene (PP), and woven or nonwoven fabrics made of polypropylene, polyethylene terephthalate (PET), methylcellulose, etc. The separator 13 may also be reinforced with a vinylidene fluoride resin compound.

[0033] The electrode laminate 11 includes a plurality of first sealing portions 21 made of insulating resin. Each of the plurality of first sealing portions 21 includes a first portion 21a, a second portion 21b, and a third portion 21c. The first portion 21a is formed in the shape of a rectangular frame when viewed from a first direction D1 and is joined (e.g., welded) to the peripheral edge 15c of the electrode plate 15. The second portion 21b is also in the shape of a rectangular frame when viewed from a first direction D1 and is positioned on a part of the first portion 21a. That is, when viewed from a first direction D1, the inner edge of the second portion 21b is located outside the inner edge of the first portion 21a. The separator 13 is positioned and joined (e.g., welded) to the portion of the first portion 21a that is exposed from the second portion 21b.

[0034] The third portion 21c has a rectangular cylindrical shape extending along the first direction D1 and is formed by joining together a plurality of first portions 21a and a plurality of second portions 21b. The first portions 21a and the second portions 21b can be formed, for example, by folding a single sheet-like member. In this case, the third portion 21c is a welded end formed, for example, by welding the folded portion of the sheet-like member (the outer end of the first portion 21a and the second portion 21b).

[0035] The second seal portion 12 is formed in an overall rectangular cylindrical shape, for example, from an insulating resin. The second seal portion 12 is provided around the electrode stack 11 so as to surround the electrode stack 11. The second seal portion 12 is joined (e.g., welded) to the first seal portion 21 so as to surround the first seal portion 21 from the outside. The second seal portion 12 is formed, for example, by resin injection molding and extends along the entire length of the electrode stack 11 in the first direction D1. The second seal portion 12 is welded to the outer surface of the first seal portion 21, for example, by the heat during injection molding.

[0036] The first seal portion 21 and the second seal portion 12 seal the spaces between adjacent bipolar electrodes 14 along the first direction D, between the negative terminal electrode 18 and the bipolar electrode 14, and between the positive terminal electrode 19 and the bipolar electrode 14, respectively. As a result, airtightly partitioned internal spaces V are formed between the bipolar electrodes 14, between the negative terminal electrode 18 and the bipolar electrode 14, and between the positive terminal electrode 19 and the bipolar electrode 14. In other words, the first seal portion 21 and the second seal portion 12 are for forming the internal spaces V between the electrodes and sealing the internal spaces V. This internal space V contains an electrolyte (not shown) consisting of an alkaline solution such as an aqueous potassium hydroxide solution. At least a portion of the electrolyte can be impregnated into the separator 13, the positive electrode active material layer 16, and the negative electrode active material layer 17.

[0037] The first sealing portion 21 and the second sealing portion 12 may be made of an insulating resin, such as polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE).

[0038] As shown in Figures 1-3, the second seal portion 12 includes a pair of outer peripheral surfaces 12s and a pair of outer peripheral surfaces 12r connecting the two outer peripheral surfaces 12s. The outer peripheral surfaces 12s and 12r are surfaces that extend along the first direction D1. Here, the outer peripheral surface 12s is a surface that intersects (is perpendicular to) the third direction D3, and the outer peripheral surface 12r is a surface that intersects (is perpendicular to) the second direction D2. Also, the length of the outer peripheral surface 12s in the second direction D2 is longer than the length of the outer peripheral surface 12r in the third direction D3. In the conductive plate 5 described above, the flow path 5a extends along the third direction D3 and opens to a pair of surfaces of the conductive plate 5 that intersect the third direction D3.

[0039] Therefore, the gap on the outer peripheral surface 12s side of the second seal portion 12 of adjacent energy storage modules 4 is used for the introduction and discharge of refrigerant to the flow path 5a (the refrigerant passes through it). On the other hand, the gap on the outer peripheral surface 12r side of the second seal portion 12 of adjacent energy storage modules 4 is not used for the introduction and discharge of refrigerant to the flow path 5a. For this reason, in the module stack 2, the gap on the outer peripheral surface 12s side of the second seal portion 12 of adjacent energy storage modules 4 is open, and the gap on the outer peripheral surface 12r side is sealed by the sealing material E.

[0040] Here, the energy storage module 4 may include a pair of metal plates 50. In this embodiment, the metal plates 50 are provided at one end (the end on the negative terminal electrode 18 side) and the other end (the end on the positive terminal electrode 19 side) of the electrode stack 11 in the first direction D1. One of the pair of metal plates 50 contacts the first surface 15a of the electrode plate 15 of the negative terminal electrode 18 with the conductive plate 5. The other of the pair of metal plates 50 contacts the second surface 15b of the electrode plate 15 of the positive terminal electrode 19 with another conductive plate 5. In this way, in the energy storage module 4, the metal plates 50 are provided further outside the negative terminal electrode 18 and the positive terminal electrode 19. The metal plate 50 (negative terminal electrode 18) located at one end in the first direction D1 constitutes the negative terminal surface of the energy storage module 4. The metal plate 50 (positive terminal electrode 19) located at the other end in the first direction D1 constitutes the positive terminal surface of the energy storage module 4.

[0041] One peripheral edge of the pair of metal plates 50 is sandwiched between a first portion 21a of a first seal portion 21 provided on the electrode plate 15 of the negative electrode terminal electrode 18 and another first portion 21a provided on the opposite side of the first portion 21a. These pair of first portions 21a are joined (e.g., welded) together by a third portion 21c. The other peripheral edge of the pair of metal plates 50 is sandwiched between a first portion 21a of a first seal portion 21 provided on the electrode plate 15 of the positive electrode terminal electrode 19 and another first portion 21a provided on the opposite side of the first portion 21a. These pair of first portions 21a are also joined (e.g., welded) together by a third portion 21c. The metal plates 50 are metal foils (uncoated foils), such as the electrode plate 15, on which no active material layer is formed.

[0042] Next, the second seal portion 12 will be described in detail. Figure 4 is a plan view of the energy storage module shown in Figures 1 to 3. Figure 5 is an enlarged view of portion P1 shown in Figure 4. Figure 5(a) is a schematic cross-sectional view along the line Va-Va in Figure 4, and Figure 5(b) is a schematic perspective view. As shown in Figures 4 and 5, the second seal portion 12 is provided with a canopy portion 60.

[0043] As will be described later, the canopy portion 60 has the function of preventing liquid adhering to the vicinity of one terminal surface of the energy storage module 4 from flowing along the outer circumferential surface of the second seal portion 12 to the other terminal surface of the energy storage module 4, thereby preventing a short circuit between the positive and negative terminal surfaces of the energy storage module 4 via the liquid. As described above, since the gap on the outer circumferential surface 12r side of the second seal portion 12 of adjacent energy storage modules 4 is sealed by the sealing material E, there is little need to provide a canopy portion 60 on the outer circumferential surface 12r of each energy storage module 4. For this reason, in the energy storage module 4, the canopy portion 60 is provided only on the outer circumferential surface 12s of the outer circumferential surfaces 12s and 12r of the second seal portion 12.

[0044] The canopy portion 60 includes a first portion 61 and a second portion 62. The first portion 61 is connected to the outer circumferential surface 12s at its base end and to the second portion 62 at its tip end. The first portion 61 is inclined such that the distance D12 from the outer circumferential surface 12s gradually increases as it moves downward (vertically downward) in the first direction D1. As a result, the upper surface (the surface facing upward in the first direction D1) 61s of the first portion 61 is an inclined surface that moves away from the outer circumferential surface 12s as it moves downward in the first direction D1. The canopy portion 60 also includes a flat portion 64 interposed between the outer circumferential surface 12s and the first portion 61. The surface 64s of the flat portion 64 facing upward in the first direction D1 is a flat surface (horizontal surface) extending along the second direction D2 and the third direction D3. Here, the first portion 61 is connected to the outer circumferential surface 12s via the flat portion 64 at its base end.

[0045] The second portion 62 extends downward from the tip of the first portion 61, substantially parallel (or substantially perpendicular) to the first direction D1. Therefore, in the second portion 62, the distance D12 from the outer circumferential surface 12s is substantially constant, regardless of its position in the first direction D1. Multiple reinforcing ribs 63 are formed on the outer circumferential surface 12s and the upper surface 61s at predetermined intervals along the extension direction of the canopy portion 60 (in this case, the second direction D2). The ribs 63 project upward from the upper surface 61s of the first portion 61 toward the first direction D1 and are connected to the outer circumferential surface 12s.

[0046] Here, a plurality of metal support columns 10 (and fasteners 9) extending along the first direction D1 are arranged on the outside of the outer peripheral surface 12s of the second seal portion 12. Therefore, in the portion of the canopy portion 60 facing the support columns 10, the canopy portion 60 comes into close proximity to the metal components. In contrast, the energy storage module 4 ensures distance between the canopy portion 60 and the support columns 10 by providing notches 70 in the canopy portion 60 to accommodate the support columns 10. This point will be explained in more detail.

[0047] Figure 6 is an enlarged view of the portion P2 shown in Figure 4. Figure 6(a) is a schematic plan view, and Figure 6(b) is a schematic perspective view. Figure 7 is a cross-sectional view of the portion P2 shown in Figure 4. Figure 7(a) is a schematic cross-sectional view along the line VIIa-VIIa in Figure 6(b), and Figure 7(b) is a schematic cross-sectional view along the line VIIb-VIIb in Figure 6(b). As shown in Figures 4, 6, and 7, a notch 70 is formed in the portion of the canopy 60 facing the support column 10 so that the canopy 60 is separated from the support column 10 (so that the distance between the canopy 60 and the support column 10 is increased).

[0048] Here, the support column 10 includes a first portion 10p facing the eaves portion 60 and a second portion 10r on the opposite side of the eaves portion 60. The through hole 10h in the support column 10 through which the fastener 9 is inserted is provided across the first portion 10p and the second portion 10r. The shape of the edge 71 of the notch 70 when viewed from the first direction D1 is complementary to the shape of the outer edge of the first portion 10p of the support column 10 when viewed from the first direction D1. Here, the shape of the outer edge of the first portion 10p of the support column 10 when viewed from the first direction D1 is an arc shape that is convex toward the eaves portion 60, and correspondingly, the shape of the edge 71 of the notch 70 when viewed from the first direction D1 is an arc shape that is concave toward the opposite side of the support column 10. As an example, the curvature of the arc of the edge 71 of the notch 70 can be equal to or greater than the curvature of the arc of the outer edge of the first portion 10p. In the canopy section 60, the distance D10 from the support column 10 is ensured to be at least a certain level at this notch 70.

[0049] A wall portion 72 is provided at the edge 71 of the notch 70. The wall portion 72 protrudes upward from the edge 71 in the first direction D1 and extends along the edge 71 (extending toward the upper surface 61s of the first portion 61 of the canopy portion 60). Here, the wall portion 72 extends along the entire edge 71 to the tip of the canopy portion 60 (the tip of the first portion 61). More specifically, the wall portion 72 is provided continuously from the tip of one of the pair of first portions 61 that sandwich the notch 70 in the extending direction of the canopy portion 60 to the tip of the other first portion 61. The wall portion 72 is inclined with respect to the first direction D1 (for example, in a cross section including the first direction D1 and the third direction D3 (Figure 7(b))) such that it moves away from the outer peripheral surface 12s as it moves upward in the first direction D1 (the distance D12 increases).

[0050] More specifically, as shown in Figure 7(a), at the end of the wall portion 72 in the extending direction along the edge portion 71 (the end of the arc), the wall portion 72 is not inclined with respect to the first direction D1, and the distance D12 is constant regardless of the position in the first direction D1. On the other hand, as shown in Figure 7(b), in most of the rest of the wall portion 72 (for example, the portion including the center in the extending direction of the wall portion 72), the wall portion 72 is inclined with respect to the first direction D1 such that it moves away from the outer peripheral surface 12s as it moves upward in the first direction D1 (so that the distance D12 increases). Here, the corners of the second seal portion 12 are chamfered, and an inclined portion is formed on the outer peripheral surface 12s. The meaning of the wall portion 72 moving away from the outer peripheral surface 12s, and the distance D12, are based on the position in the third direction when no inclined portion is formed on the outer peripheral surface 12s (the position in the third direction other than the inclined portion on the outer peripheral surface 12s).

[0051] The height of the wall portion 72 in the first direction D1 is greater than or equal to the height of the portion 12i of the second seal portion 12 corresponding to the notch 70 in the first direction D1. That is, the upper end surface 72t of the wall portion 72 is substantially flush with the upper end surface 12t (upper end surface of the seal portion) of the portion 12i corresponding to the notch 70 of the second seal portion 12, or is located above the upper end surface 12t in the first direction (i.e., it protrudes upward from the upper end surface 12t in the first direction D1). This makes it possible, for example, if liquid flows out from the gap between the second seal portions 12 of adjacent energy storage modules 4 towards the notch 70, to be reliably received by the wall portion 72 and guided (flowed) toward the upper surface 61s of the eaves portion 60.

[0052] As shown in Figure 6, the portion 12i corresponding to the notch 70 of the second seal portion 12 is, for example, a strip-shaped portion that overlaps with the notch 70 and extends along the first direction D1 when viewed from a third direction D3 intersecting the outer peripheral surface 12s.

[0053] On the other hand, the height of the wall portion 72 in the first direction D1 is less than or equal to the height of the highest part 12k of the second seal portion 12 in the first direction (see Figure 5(b) for part 12k). That is, the upper end surface 72t of the wall portion 72 is located below the upper end surface of the highest part 12k of the second seal portion 12 in the first direction. Part 12k is a different part from part 12i, and is, for example, a raised part provided at a position corresponding to the rib 63 of the second seal portion 12. This prevents the wall portion 72 from hindering the stacking of multiple energy storage modules 4, and also prevents it from hindering the introduction and exit of refrigerant to the flow path 5a that utilizes the gap between the second seal portions 12 of adjacent energy storage modules 4.

[0054] The shape of the wall portion 72 when viewed from the first direction D1 is equivalent to the shape of the edge portion 71. Therefore, in this case, the shape of the wall portion 72 when viewed from the first direction D1 is arc-shaped, corresponding to the shape of the edge portion 71. Furthermore, as described above, the wall portion 72 is inclined to move away from the outer peripheral surface 12s as it moves upward in the first direction D1. Therefore, in this example, the shape of the first surface 72s (liquid guide surface) on the outer peripheral surface 12s side of the wall portion 72, and the shape of the second surface 72r (surface facing the support column 10) on the opposite side of the first surface 72s, are partial conical surfaces that shrink as they move upward in the first direction D1.

[0055] As shown in Figure 4, when viewed from the first direction D1, the support column 10 is located outside the notch 70. In other words, when viewed from the first direction D1, the support column 10 is located outside the tip surface of the canopy portion 60 (the outer surface of the second portion 62). Therefore, even if the notch 70 is not provided in the canopy portion 60, the support column 10 will not come into contact with the canopy portion 60. However, if the notch 70 is not provided and the support column 10 and the canopy portion 60 are extremely close, there is a risk that the support column 10 and the canopy portion 60 may come into contact due to large dimensional tolerances or vibrations and shocks, which is undesirable. As a variation, when viewed from the first direction D1, at least a portion of the support column 10 may be located inside the notch 70 (i.e., inside the tip surface of the canopy 60 (the outer surface of the second portion 62)) within a range where the distance D10 between the support column 10 and the canopy portion 60 is maintained above a certain level.

[0056] As described above, in the energy storage device 1, a second seal portion 12 is provided around the electrode stack 11, and a canopy portion 60 is formed on the outer circumferential surface 12s of the second seal portion 12, having an upper surface 61s that slopes downward so as it moves away from the outer circumferential surface 12s. Therefore, when liquid adheres to the outer circumferential surface 12s of the second seal portion 12, the liquid moves downward on the upper surface 61s of the canopy portion 60, separating it from the outer circumferential surface 12s and causing it to fall off the upper surface 61s. Thus, short circuits caused by the liquid are suppressed. The liquid adhering to the outer circumferential surface 12s may be, for example, electrolyte leaked from inside the energy storage module 4 or condensation from outside the energy storage module 4.

[0057] On the other hand, in the energy storage device 1, the connecting members (particularly the support columns 10) for restraining the electrode stack 11 are positioned outside the second seal portion 12. Furthermore, a notch 70 is provided in the portion of the canopy portion 60 facing the support column 10, spaced apart from the support column 10. As a result, compared to the case where the notch 70 is not provided in the canopy portion 60, it is possible to position the support column 10 closer to the outer circumferential surface 12s of the second seal portion 12 while maintaining the distance D10 between the support column 10 and the canopy portion 60. Thus, the size of the device is suppressed.

[0058] Furthermore, in the energy storage device 1, a wall portion 72 is formed on the edge 71 of the notch 70, extending along the edge 71 while protruding upward in the first direction D1. Therefore, the wall portion 72 prevents liquid adhering to the outer peripheral surface 12s of the second seal portion 12 at the position corresponding to the notch 70 from entering the gap between the notch 70 and the support column 10. In other words, even if a notch 70 is provided as described above, liquid junctions caused by the notch 70 are suppressed. As described above, the energy storage device 1 makes it possible to suppress liquid junctions while keeping the size of the device down.

[0059] Furthermore, in the energy storage device 1, the wall portion 72 extends along the entire edge portion 71 so as to reach the tip of the eaves portion 60. As a result, liquid adhering to the outer peripheral surface 12s of the second seal portion 12 at the position corresponding to the notch 70 is reliably guided to the upper surface 61s of the eaves portion 60 by the wall portion 72 provided on the edge portion 71 of the notch 70. Thus, liquid entanglement can be suppressed more reliably.

[0060] Furthermore, in the energy storage device 1, the upper end surface 72t of the wall portion 72 in the first direction D1 is flush with the upper end surface 12t of the portion 12i corresponding to the notch 70 in the second seal portion 12, or is located above the upper end surface 12t in the first direction D1. Therefore, liquid moving from the upper end surface 12t of the second seal portion 12 toward the outer peripheral surface 12s is prevented from overflowing the wall portion 72 and entering the gap between the notch 70 and the support column 10.

[0061] Furthermore, in the energy storage device 1, the shape of the outer edge of the portion of the support column 10 facing the outer surface 12s is arc-shaped when viewed from the first direction D1, and the shape of the edge 71 of the notch 70 and the shape of the wall portion 72 when viewed from the first direction D1 are arc-shaped, which are recessed in accordance with the shape of the outer edge of the support column 10. Therefore, while maintaining the distance D10 between the wall portion 72 and the support column 10, it is possible to increase the distance between the outer surface 12s of the second seal portion 12 at the end (end of the arc) of the wall portion 72, making it easier for liquid to flow toward the canopy portion 60.

[0062] Furthermore, in the energy storage device 1, the wall portion 72 is inclined so that it moves away from the outer peripheral surface 12s as it moves upward in the first direction D1. As a result, compared to the case where the wall portion 72 extends parallel to the first direction D1, the surface area of ​​the wall portion 72 as viewed from the first direction D1 is increased, making it easier to flow more liquid towards the eaves portion 60. In addition, with this configuration, for example, when the second seal portion 12 and the wall portion 72 are formed by injection molding, the wall portion 72 becomes easier to demold, thus simplifying manufacturing.

[0063] The embodiments described above illustrate one aspect of the energy storage device of the present disclosure. Therefore, the energy storage device according to the present disclosure may be any modification of the energy storage device 1 described above.

[0064] For example, in the above embodiment, the energy storage device 1 had a plurality of energy storage modules 4 stacked along the first direction D1. However, the number of energy storage modules 4 in the energy storage device 1 is arbitrary and may be, for example, one.

[0065] Furthermore, in the above embodiment, the shape of the outer edge of the portion of the support column 10 facing the outer circumferential surface 12s and the shape of the edge 71 and wall 72 of the notch 70 are complementary, and for example, they are arc-shaped. However, these shapes may be set independently of each other, or they may be shapes other than arc-shaped. For example, the shape of the outer edge of the portion of the support column 10 facing the outer circumferential surface 12s may be rectangular, and the shape of the edge 71 and wall 72 of the notch 70 may be arc-shaped, or vice versa. However, the portion of the support column 10 facing the outer circumferential surface 12s is also the portion that receives the refrigerant supplied from the flow path 5a of the conductive plate 5. Therefore, if the portion is arc-shaped, it is advantageous for the smooth flow of the refrigerant supplied from the flow path 5a of the conductive plate 5 compared to, for example, the case where the portion is rectangular.

[0066] Furthermore, in the above embodiment, the wall portion 72 extended over the entire edge portion 71 of the notch 70, but it may also be provided on a portion of the edge portion 71 of the notch 70. In this case, for example, the wall portion 72 may be provided on a portion of the edge portion 71 of the notch 70, including the point closest to the outermost surface 12s.

[0067] Furthermore, in the above embodiment, the height of the wall portion 72 in the first direction D1 was equal to or greater than the height of the portion 12j corresponding to the notch 70 of the second seal portion 12 in the first direction D1. However, the height of the wall portion 72 in the first direction D1 may be less than the height of the portion 12j corresponding to the notch 70 of the second seal portion 12 in the first direction D1. That is, the upper end surface 72t of the wall portion 72 may be located below the upper end surface 12t of the portion 12j in the first direction D1.

[0068] Furthermore, in the above embodiment, the wall portion 72 extended so as to move upward in the first direction D1, moving away from the outer peripheral surface 12s; however, it may extend such that the distance D12 from the outer peripheral surface 12s remains constant regardless of the position in the first direction D1.

[0069] Furthermore, in the above embodiment, the pair of restraint plates 8 were connected by fastening them together with fasteners 9. However, the restraint plates 8 may also be connected by pinning, welding, or other methods instead of fastening.

[0070] The embodiments described above are described below.

[0071] The energy storage device according to this disclosure is an "energy storage device comprising: (1) an electrode stack including a plurality of electrodes stacked along a first direction, and an energy storage module having a seal portion provided around the electrode stack to seal the spaces between the electrodes; a pair of restraint plates arranged to sandwich the electrode stack in the first direction; and a plurality of connecting members arranged outside the seal portion when viewed from the first direction, extending along the first direction and restraining the electrode stack by connecting the pair of restraint plates along the first direction, wherein the outer peripheral surface of the seal portion along the first direction has a canopy portion having an upper surface that slopes so as to move downward in the first direction away from the outer peripheral surface, and the portions of the canopy portion facing each of the connecting members have notches formed so as to be spaced apart from the connecting members, and the edges of the notches have wall portions formed that protrude upward in the first direction from the edges and extend along the edges."

[0072] The energy storage device relating to this disclosure may also be [2] "the energy storage device according to [1] above, wherein the wall portion extends over the entire edge portion so as to reach the tip of the eaves portion."

[0073] The energy storage device according to this disclosure may be [3] "the energy storage device according to [1] or [2] above, wherein the upper end surface of the wall portion in the first direction is flush with the upper end surface of the seal portion, which is the upper end surface in the first direction of the portion of the seal portion corresponding to the notch, or is located above the upper end surface of the seal portion in the first direction."

[0074] The energy storage device according to this disclosure may be [4] "the energy storage device according to any one of [1] to [3] above, wherein the shape of the outer edge of the portion of the connecting member facing the outer peripheral surface is arc-shaped when viewed from the first direction, and the shape of the edge of the notch and the shape of the wall are arc-shaped that are recessed in accordance with the shape of the outer edge of the connecting member when viewed from the first direction."

[0075] The energy storage device relating to this disclosure may also be [5] "the energy storage device according to any one of [1] to [4] above, wherein the wall portion is inclined to move away from the outer peripheral surface as it moves upward in the first direction." [Explanation of Symbols]

[0076] 1...Energy storage device, 4...Energy storage module, 8...Restraining plate, 9...Fastener (connecting member), 10...Support column (connecting member), 11...Electrode stack, 12...Second seal part (seal part), 12s...Outer surface, 60...Eaves part, 61s...Top surface, 70...Notch, 71...Edge part, 72...Wall part.

Claims

1. An electrode stack comprising a plurality of electrodes stacked along a first direction, and a power storage module having a sealing portion provided around the electrode stack to seal the spaces between the electrodes, A pair of restraint plates arranged to sandwich the electrode stack in the first direction, A plurality of connecting members are arranged on the outside of the sealing portion when viewed from the first direction, extending along the first direction and connecting the pair of restraining plates along the first direction, thereby restraining the electrode laminate. Equipped with, The outer circumferential surface of the sealing portion along the first direction is formed with a canopy portion having an upper surface that slopes away from the outer circumferential surface as it extends downward in the first direction. In the portion of the canopy facing each of the connecting members, a notch is formed so as to be spaced apart from the connecting member. A wall portion is formed at the edge of the notch, projecting upward from the edge in the first direction and extending along the edge. Energy storage device.

2. The wall portion extends along the entire edge so as to reach the tip of the eaves portion. The energy storage device according to claim 1.

3. The upper end surface of the wall portion in the first direction is flush with the upper end surface of the seal portion, which is the upper end surface of the portion of the seal portion corresponding to the notch in the first direction, or is located above the upper end surface of the seal portion in the first direction. The energy storage device according to claim 1.

4. The shape of the outer edge of the portion of the connecting member facing the outer peripheral surface is arc-shaped when viewed from the first direction. The shape of the edge portion and the wall portion of the notch are arc-shaped, which are recessed in a manner corresponding to the shape of the outer edge of the connecting member when viewed from the first direction. The energy storage device according to claim 1.

5. The wall portion is inclined such that it moves away from the outer peripheral surface as it moves upward in the first direction. The energy storage device according to any one of claims 1 to 4.

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