Power storage module

Abstract

This power storage module is provided with: an electrode laminate including a plurality of laminated electrodes; and a sealing material provided around the electrode stack so as to seal between the electrodes, the electrode stack having: a first end surface and a second end surface in the stacking direction of the plurality of electrodes; and a side surface extending in the stacking direction so as to connect the first end surface and the second end surface, the seal having: a side surface portion provided on the side surface; a first extending part extending from the side surface part to the first end surface; a second extending part extending from the side surface part to the second end surface; an eave extending from the side surface portion to the outside of the electrode laminate; and a rib provided on the eave, the side surface portion having: a connection portion to which the eave is connected; a first side surface portion located between the connection portion and the first extension portion; the rib connects the eave and the first side surface portion, and the second side surface portion is thicker than the first side surface portion in a direction orthogonal to the side surface.

Description

Technical Field

[0001] The present disclosure relates to a power storage module. Background Art

[0002] A power storage module is known, which includes a seal including a side portion provided on the side of an electrode stack and a pair of protruding portions extending from the side portion to a pair of end faces of the electrode stack (for example, refer to WO2020 / 138110A1). The power storage unit described in WO2020 / 138110A1 includes a sealing portion and a flange portion formed on a long wall portion of the sealing portion. The flange portion includes an inclined portion having an inclined surface extending downward as it moves away from the outer peripheral surface of the long wall portion in the horizontal direction. The liquid accumulated in the gap between certain power storage units drips from the gap to the flange portion and moves on the inclined surface of the flange portion, thereby moving away from the gap between other power storage units in the horizontal direction. Thereby, it is achieved to prevent the liquid from entering the gap of other power storage units. As a result, a short circuit (liquid short circuit) caused by the liquid can be suppressed. Summary of the invention

[0003] When the sealing portion of the power storage cell described in WO2020 / 138110A1 is formed by resin injection molding, the wall thickness may vary between the pair of protruding portions. If the wall thickness varies between the pair of protruding portions, the strength of the power storage module may not be ensured.

[0004] An object of the present disclosure is to provide a power storage module capable of ensuring strength.

[0005] A storage battery module according to one embodiment of the present invention comprises: an electrode stack including a plurality of stacked electrodes; and a sealant disposed around the electrode stack in a manner to seal the electrodes, the electrode stack comprising: a first end face and a second end face in a stacking direction of the plurality of electrodes; and a side face extending in the stacking direction in a manner to connect the first end face and the second end face, the sealant comprising: a side face portion disposed on the side face; a first extension portion extending from the side face portion to the first end face; a second extension portion extending from the side face portion to the second end face; an eave extending from the side face portion to the outside of the electrode stack; and a rib disposed on the eave, the side face portion comprising: a connecting portion connected to the eave; a first side face portion located between the connecting portion and the first extension portion; and a second side face portion located between the connecting portion and the second extension portion, the rib connecting the eave to the first side face portion, and the second side face portion being thicker than the first side face portion in a direction perpendicular to the side face.

[0006] In this power storage module, since the rib is connected to the eaves and the first side portion of the side portion, when injection molding is performed using the formation space of the rib (hereinafter, also referred to as the rib) as the injection port of the resin, in the path of the resin from the rib to the formation space of the first side portion (hereinafter, also referred to as the first side portion), in addition to the path passing through the formation space of the eaves (hereinafter, also referred to as the eaves), there is also a path that directly connects the rib and the first side portion without passing through the eaves. In contrast, in the path of the resin from the rib to the formation space of the second side portion of the side portion (hereinafter, also referred to as the second side portion), there is only a path passing through the eaves. Therefore, the resin injected from the rib is easier to flow into the first side portion than the second side portion. Since the second side portion is thicker than the first side portion, the resin is easier to flow in the second side portion than in the first side portion. Therefore, it is difficult for the resin flowing into the space formed by the first extension located downstream of the first side portion (hereinafter, also referred to as the first extension) to have a deviation from the resin flowing into the space formed by the second extension located downstream of the second side portion (hereinafter, also referred to as the second extension). As a result, it is possible to suppress the deviation in the wall thickness between the first extension and the second extension. As a result, the strength of the storage module can be ensured.

[0007] The second side surface portion may include a thick wall portion at a position facing the rib across the eaves in the stacking direction.

[0008] Alternatively, the rib may include a plate-shaped main body portion connecting the eaves to the first side portion and a column portion separated from the side portion and protruding from the eaves in the stacking direction, wherein the column portion is thicker than the main body portion in a direction perpendicular to the stacking direction and parallel to the side.

[0009] The main body portion may be connected to the first side surface portion at a position spaced apart from the first extension portion in the stacking direction.

[0010] Alternatively, the main body portion includes: a first main body portion connected to the first side portion; and a second main body portion connected to the column portion, wherein the first main body portion is separated from the first extension portion by a distance in the stacking direction longer than the second main body portion is separated from the first extension portion in the stacking direction.

[0011] Another embodiment of the present disclosure relates to a storage module comprising: an electrode stack including a plurality of electrodes stacked in a stacking direction; and a sealant provided around the electrode stack in a manner to seal the electrodes, the electrode stack having: a first end face and a second end face in the stacking direction; and a side face extending in the stacking direction in a manner to connect the first end face and the second end face, the sealant having: a side face portion provided on the side face; a first extension portion extending from the side face portion to the first end face; and a second extension portion extending from the side face portion to the first end face. protrudes to the second end face; an eave extending from the side portion toward the outside of the electrode stack; and a rib arranged on the eave, the side portion comprising: a connecting portion connected to the eave; a first side portion located between the connecting portion and the first extending portion; and a second side portion located between the connecting portion and the second extending portion, the rib comprising: a plate-shaped main body connecting the eave and the first side portion; and a column portion separated from the first side portion and protruding from the eave in the stacking direction, the column portion being thicker than the main body portion in a direction perpendicular to the stacking direction and parallel to the side surface.

[0012] In this power storage module, since the rib is connected to the eaves and the first side portion of the side portion, when the rib is used as the injection port for resin injection molding, in the path of the resin from the rib to the first side portion, in addition to the path through the eaves, there is also a path in which the rib and the first side portion are directly connected without passing through the eaves. In contrast, in the path of the resin from the rib to the second side portion of the side portion, there is only a path through the eaves. Therefore, the resin injected from the rib is easier to flow into the first side portion than the second side portion. In addition to the plate-shaped main body, the rib has a column part that is separated from the first side portion and protrudes from the eaves. Since the column part is thicker than the main body, if the space for forming the column part (hereinafter, also referred to as the column part) is used as the injection port for resin injection molding, the resin is easier to flow into the eaves. As a result, it is possible to suppress the resin from flowing directly from the rib to the first side portion without passing through the eaves. That is, compared with the case where the column part has the same thickness as the main body, the amount of resin flowing into the first side portion and the second side portion is less likely to vary. Therefore, the amount of resin flowing into the first extension located downstream of the first side portion and the second extension located downstream of the second side portion is unlikely to vary. As a result, the variation in wall thickness between the first extension and the second extension can be suppressed. As a result, the strength of the power storage module can be ensured.

[0013] In the power storage module according to the above-mentioned other aspect, the main body portion may be connected to the first side surface portion at a position spaced apart from the first extension portion in the stacking direction.

[0014] In the power storage module involved in the above-mentioned other scheme, the main body may also include: a first main body part, which is connected to the first side part; and a second main body part, which is connected to the column part, and the distance between the first main body part and the first extension part in the stacking direction is longer than the distance between the second main body part and the first extension part in the stacking direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic cross-sectional view showing a cross section including a first direction and a second direction of a power storage device according to an embodiment.

[0016] Figure 2 This is a schematic cross-sectional view showing a cross section including a first direction and a third direction of a power storage device according to an embodiment.

[0017] Figure 3 It is shown Figure 1 and Figure 2 A schematic cross-sectional view of the power storage module shown.

[0018] Figure 4 It is shown Figures 1 to 3 A perspective view of the power storage module shown.

[0019] Figure 5 It is a perspective view showing an enlarged view of a rib and its surroundings.

[0020] Figure 6 It is a perspective view showing an enlarged view of a rib and its surroundings.

[0021] Figure 7 It is a plan view showing the rib and its surroundings in an enlarged manner.

[0022] Figure 8 It is a side view showing the rib and its surroundings in an enlarged manner.

[0023] Fig. 9 It is a cross-sectional view showing the rib and its surroundings in an enlarged manner.

[0024] Fig.10 This is a cross-sectional view for explaining the inner seal forming process.

[0025] Fig.11 This is a cross-sectional view for explaining the outer seal forming step. DETAILED DESCRIPTION

[0026] Hereinafter, an embodiment of the power storage device will be described with reference to the accompanying drawings. In the description of each figure, the same reference numerals are given to the same or equivalent elements, and repeated descriptions are sometimes omitted. In addition, in each figure, an orthogonal coordinate system consisting 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 is illustrated. As an example, the first direction D1 is a vertical direction, and the second direction D2 and the third direction D3 are two horizontal directions that intersect each other.

[0027] Figure 1 This is a schematic cross-sectional view showing a cross section including a first direction and a second direction of a power storage device according to an embodiment. Figure 2 This is a schematic cross-sectional view showing a cross section including a first direction and a third direction of a power storage device according to an embodiment. Figure 1 and Figure 2 The power storage device 1 shown 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 stack 2 including a plurality of power storage modules 4 stacked along a first direction D1; and a restraining member 3 for applying a restraining load to the module stack 2 along the first direction D1.

[0028] The module stack 2 includes a plurality of (here, 3) power storage modules 4 and a plurality of (here, 2) conductive plates 5. The power storage module 4 is, for example, a bipolar battery, and is rectangular when viewed from the first direction D1. More specifically, the power storage module 4 is a rectangular shape having long sides and short sides 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 is exemplified.

[0029] In the module stack 2, the conductive plate 5 is interposed between the power storage modules 4 adjacent to each other in the first direction D1. Thus, the plurality of power storage modules 4 are electrically connected via the conductive plate 5. More specifically, each power storage module 4 has a positive terminal surface at one end surface in the first direction D1 and a negative terminal surface at the other end surface in the first direction D1, and the plurality of power storage modules 4 stacked via the conductive plate 5 are connected in series. A collector plate 6 from which a positive terminal 6a is led is arranged outside the power storage module 4 located at one end in the first direction D1 of the module stack 2, and the collector plate 6 is electrically connected to the power storage module 4. In addition, a collector plate 7 from which a negative terminal 7a is led is arranged outside the power storage module 4 located at the other end in the first direction D1 of the module stack 2, and the collector plate 7 is electrically connected to the power storage module 4. The power storage device 1 is charged and discharged by using these positive terminals 6a and negative terminals 7a.

[0030] A plurality of flow paths 5a through which a refrigerant such as air flows are provided inside the conductive plate 5. The flow paths 5a extend, for example, in a direction (here, a third direction D3) that intersects (is perpendicular to) the first direction D1 and the lead-out directions of the positive terminal 6a and the negative terminal 7a. In addition to the function of serving as a connecting member that electrically connects the power storage modules 4 to each other, the conductive plate 5 also serves as a heat dissipation member that dissipates heat generated in the power storage modules 4 by circulating the refrigerant in these flow paths 5a.

[0031] 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 9 such as bolts that connect the restraining plates 8 to each other by fastening the restraining plates 8 to each other; and a support 10 that accommodates the main body of the fastener 9 (for example, the shaft of the bolt). The restraining plate 8 is a rectangular metal plate having an area that is one circle larger than the area of ​​the storage module 4 and the conductive plate 5 viewed from the first direction. The restraining plate 8 is a rectangular shape having long sides and short sides when viewed from the first direction D1. A plate-shaped insulating member F is provided on the inner side surface of the restraining plate 8 (the surface on the module stack 2 side). That is, the collector plate 6 or the collector plate 7, and the insulating member F are interposed between the module stack 2 and the restraining plate 8. As a result, the restraining plate 8 is insulated from the module stack 2 (more specifically, the collector plates 6 and 7).

[0032] An insertion hole 8a is provided at the edge of one of the restraining plates 8 at a position outside the module stack 2 as viewed in the first direction D1, and a threaded hole 8b is provided at the edge of the other restraining plate 8 at a position opposite to the insertion hole 8a. The fastener 9 passes through the insertion hole 8a of one restraining plate 8 toward the threaded hole 8b of the other restraining plate 8 and is screwed into the threaded hole 8b of the other restraining plate 8. Thus, the power storage module 4 and the conductive plate 5 are clamped by the restraining plates 8 and unitized as the module stack 2, and a restraining load is applied to the module stack 2 along the first direction.

[0033] In this way, the fastener 9 is arranged outside the module stack 2, extends along the first direction D1, and fastens the pair of restraining plates 8 to each other along the first direction D1 to restrain the module stack 2. The support 10 is interposed between the pair of restraining plates 8 and extends along the first direction D1 together with the fastener 9. The support 10 specifies the restraining force on the module stack 2 by specifying the distance between the pair of restraining plates 8 in the first direction D1.

[0034] In the power storage device 1, a plurality of connection members composed of one fastener 9 and one support 10 for accommodating the fastener 9 are arranged along the long side of the restraining plate 8 when viewed from the first direction D1. In addition, the connection members are opposed to each other in the direction along the short side of the restraining plate 8 when viewed from the first direction D1. And, the closer the opposed connection members are to each other, the more uniform the restraining load can be applied to the power storage module 4 via the restraining plate 8.

[0035] Figure 3 It is shown Figure 1 and Figure 2 A schematic cross-sectional view of the power storage module shown. Figure 4 It is shown Figure 1 to Figure 3 The three-dimensional diagram of the power storage module shown in FIG. Figure 3 and Figure 4 As shown, the power storage module 4 includes an electrode stack 11 and a second sealing portion 12 made of resin 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 is consistent with the stacking direction of the power storage module 4.

[0036] The bipolar electrode 14 includes an electrode plate 15 including 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 is opposite to the negative electrode active material layer 17 of another bipolar electrode 14 adjacent in the first direction D1 via the separator 13. In the electrode stack 11, the negative electrode active material layer 17 of one bipolar electrode 14 is opposite to the positive electrode active material layer 16 of another bipolar electrode 14 adjacent in the first direction D1 via the separator 13.

[0037] The negative terminal electrode 18 includes an electrode plate 15 and a negative active material layer 17 provided on the second surface 15b of the electrode plate 15. No active material layer is provided on the first surface 15a of the electrode plate 15 of the negative terminal electrode 18. The negative terminal electrode 18 is arranged at one end of the electrode stack 11 in the first direction D1 in such a manner that the second surface 15b thereof becomes the inner side (the center side in the first direction D1) of the electrode stack 11. The negative active material layer 17 of the negative terminal electrode 18 is opposite to the positive active material layer 16 of the bipolar electrode 14 at one end in the first direction D1 via the separator 13.

[0038] The positive terminal electrode 19 includes an electrode plate 15 and a positive active material layer 16 provided on a first surface 15a of the electrode plate 15. No active material layer is provided on a second surface 15b of the electrode plate 15 of the positive terminal electrode 19. The positive terminal electrode 19 is arranged at the other end of the electrode stack 11 in the first direction D1 in such a manner that the first surface 15a thereof becomes the inner side of the electrode stack 11. The positive active material layer 16 of the positive terminal electrode 19 is opposite to the negative active material layer 17 of the bipolar electrode 14 at the other end in the first direction D1 via the separator 13.

[0039] The first surface 15a of the electrode plate 15 of the negative terminal electrode 18 is a surface facing the outside of the electrode stack 11. The first surface 15a of the negative terminal electrode 18 is electrically connected to the conductive plate 5 via a metal plate 50 described later. In addition, the second surface 15b of the electrode plate 15 of the positive terminal electrode 19 is a surface facing the outside of the electrode stack 11. The second surface 15b of the positive terminal electrode 19 is electrically connected to another conductive plate 5 via a metal plate 50 described later.

[0040] The electrode plate 15 includes a metal such as nickel or a nickel-plated steel plate. As an example, the electrode plate 15 is a rectangular metal foil including nickel. The peripheral portion 15c of the electrode plate 15 (the peripheral portion of the bipolar electrode 14, the negative terminal electrode 18, and the positive terminal electrode 19) is in the shape of a rectangular frame, and is an area where the positive electrode active material layer 16 and the negative electrode active material layer 17 are not formed. As the positive electrode active material constituting the positive electrode active material layer 16, for example, nickel hydroxide can be listed. As the negative electrode active material constituting the negative electrode active material layer 17, for example, a hydrogen storage alloy can be listed.

[0041] The separator 13 is formed into a sheet, for example. Examples of the separator 13 include porous films made of polyolefin resins such as polyethylene (PE) and polypropylene (PP), woven fabrics or nonwoven fabrics made of polypropylene, polyethylene terephthalate (PET), methylcellulose, etc. The separator 13 may also be a separator reinforced with a vinylidene fluoride resin compound.

[0042] The electrode stack 11 includes: a plurality of first sealing portions 21, which include an insulating resin. The plurality of first sealing portions 21 each include a first portion 21a, a second portion 21b, and a third portion 21c. The first portion 21a is formed in a rectangular frame shape as viewed from the first direction D1, and is joined (e.g., welded) to the peripheral portion 15c of the electrode plate 15. The second portion 21b is formed in a rectangular frame shape as viewed from the first direction D1, and is arranged on a portion of the first portion 21a. That is, as viewed from the first direction D1, the inner edge of the second portion 21b is located at a position further outward than the inner edge of the first portion 21a. The peripheral portion of the separator 13 is arranged on the portion of the first portion 21a exposed from the second portion 21b and is joined (e.g., welded) thereto.

[0043] The third part 21c is in the shape of a rectangular tube extending along the first direction D1, and integrates a plurality of first parts 21a and a plurality of second parts 21b by joining them together. The first part 21a and the second part 21b can be formed, for example, by folding a sheet-like member. In this case, the third part 21c is, for example, a fused end formed by fusing the bending parts (the outer ends of the first part 21a and the second part 21b) of the sheet-like member arranged in the first direction D1 to each other. The third part 21c does not necessarily have to be arranged on the entire periphery of the first sealing part 21, and can also be partially arranged on the periphery of the first sealing part 21.

[0044] The electrode stack 11 has: a first end face 11a and a second end face 11b in the first direction D1; and a side face 11c extending in the first direction D1 in a manner connecting the first end face 11a and the second end face 11b. The first end face 11a is composed of the outer surface of the metal plate 50 constituting the negative terminal face of the storage module 4 and the outer surface of the first sealing portion 21 provided on the metal plate 50. The second end face 11b is composed of the outer surface of the metal plate 50 constituting the positive terminal face of the storage module 4 and the outer surface of the first sealing portion 21 provided on the metal plate 50. The side face 11c is composed of the outer surface of the portion 21c.

[0045] The second sealing portion 12 is formed of, for example, an insulating resin and is formed in a rectangular cylindrical shape as a whole. The second sealing portion 12 is provided around the electrode stack 11 so as to surround the electrode stack 11. The second sealing portion 12 is formed by, for example, injection molding of a resin and extends over the entire length of the electrode stack 11 along the first direction D1.

[0046] The second sealing portion 12 has an inner seal 23 and an outer seal 24 (seal). The inner seal 23 is joined to the first sealing portion 21 in a manner of surrounding the first sealing portion 21 from the outside. The inner seal 23 is, for example, fused to the outer surface of the first sealing portion 21 by the heat during injection molding. The inner seal 23 is in contact with the side surface 11c and is disposed on the side surface 11c. The inner seal 23 covers the entire side surface 11c in the first direction D1. The length of the inner seal 23 in the first direction D1 is equal to the length of the side surface 11c in the first direction D1. In addition, the inner seal 23 is arranged in a cylindrical shape in a manner of covering the entire circumference of the electrode stack 11 as viewed from the first direction D1.

[0047] The outer seal 24 is joined to the inner seal 23 so as to surround the inner seal 23 from the outside. The outer seal 24 has a side portion 25, a first extension portion 26, and a second extension portion 27. The side portion 25, the first extension portion 26, and the second extension portion 27 are integrally formed, for example, by injection molding. The side portion 25 is provided on the side surface 11c via the inner seal 23. The side portion 25 is fused to the outer surface of the inner seal 23 by the heat during injection molding, for example. In addition, the outer seal 24 is provided in a cylindrical shape so as to cover the entire circumference of the electrode stack 11 as viewed from the first direction D1.

[0048] The first extension portion 26 extends from one end of the side portion 25 in the first direction D1 to the first end surface 11a. The second extension portion 27 extends from the other end of the side portion 25 in the first direction D1 to the second end surface 11b. That is, the first extension portion 26 is a portion extending inwardly from the inner peripheral edge of the side portion 25 as viewed in the first direction D1. Similarly, the second extension portion 27 is a portion extending inwardly from the inner peripheral edge of the side portion 25 as viewed in the first direction D1. As viewed in the first direction D1, the inner edge 26d of the first extension portion 26 and the inner edge 27d of the second extension portion 27 are located at a position further outwardly than the inner edge 21d of the first sealing portion 21. The first extension portion 26 and the second extension portion 27 have mutually equal thicknesses (length in the first direction D1). The first extension portion 26 and the second extension portion 27 are continuously provided on all sides of the electrode plate 15. The first extending portion 26 and the second extending portion 27 are formed in a rectangular frame shape when viewed from the first direction D1.

[0049] The first sealing portion 21 and the second sealing portion 12 seal the bipolar electrodes 14 adjacent to each other in the first direction D1, the negative terminal electrode 18 and the bipolar electrode 14, and the positive terminal electrode 19 and the bipolar electrode 14, respectively. Thus, airtightly separated 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, respectively. That is, the first sealing portion 21 and the second sealing portion 12 are used to form the internal space V between the electrodes and seal the internal space V. In the internal space V, an electrolyte (not shown) including an alkaline solution such as an aqueous potassium hydroxide solution is contained. 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.

[0050] The first sealing portion 21 and the second sealing portion 12 are, for example, insulating resins, and can be made of polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE).

[0051] like Figure 1 to Figure 4As shown, the second sealing portion 12 includes a pair of outer peripheral surfaces 12s and a pair of outer peripheral surfaces 12r connecting the outer peripheral surfaces 12s to each other. The outer peripheral surface 12s and the outer peripheral surface 12r are surfaces extending along the first direction D1. Here, the outer peripheral surface 12s is a surface intersecting (orthogonal) with the third direction D3, and the outer peripheral surface 12r is a surface intersecting (orthogonal) with the second direction D2. In addition, 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 above-mentioned conductive plate 5, the flow path 5a extends along the third direction D3 and opens on a pair of surfaces of the conductive plate 5 intersecting with the third direction D3.

[0052] Therefore, the gap on the outer peripheral surface 12s side of the second sealing portion 12 of the adjacent power storage module 4 is used for the introduction and extraction of the refrigerant relative to the flow path 5a (for the refrigerant to pass through). On the other hand, the gap on the outer peripheral surface 12r side of the second sealing portion 12 of the adjacent power storage module 4 is not used for the introduction and extraction of the refrigerant relative to the flow path 5a. Therefore, in the module stack 2, the gap on the outer peripheral surface 12s side of the second sealing portion 12 of the adjacent power storage module 4 is open, while the gap on the outer peripheral surface 12r side is filled with the sealing material E.

[0053] Here, the power storage module 4 may also include a pair of metal plates 50. In the present 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 is in contact with the first surface 15a of the electrode plate 15 of the negative terminal electrode 18 and the conductive plate 5. The other metal plate 50 of the pair of metal plates 50 is in contact with the second surface 15b of the electrode plate 15 of the positive terminal electrode 19 and another conductive plate 5. In this way, in the power 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 disposed at one end of the power storage module 4 in the first direction D1 is in contact with the negative terminal electrode 18, and constitutes the negative terminal surface of the power storage module 4. Furthermore, the metal plate 50 disposed at the other end of the electricity storage module 4 in the first direction D1 is in contact with the positive terminal electrode 19 , and constitutes a positive terminal surface of the electricity storage module 4 .

[0054] One peripheral edge of a pair of metal plates 50 is sandwiched between the first portion 21a of the first sealing portion 21 of the electrode plate 15 provided at the negative terminal electrode 18 and another first portion 21a provided at the opposite side of the first portion 21a. The pair of first portions 21a are integrated by being joined (e.g., welded) by the third portion 21c. The other peripheral edge of a pair of metal plates 50 is sandwiched between the first portion 21a of the first sealing portion 21 of the electrode plate 15 provided at the positive terminal electrode 19 and another first portion 21a provided at the opposite side of the first portion 21a. The pair of first portions 21a are also integrated by being joined (e.g., welded) by the third portion 21c. The metal plate 50 is an uncoated foil on both sides of which an active material layer is not formed. As the metal plate 50, the same metal foil (uncoated foil) as that of the electrode plate 15 can be used.

[0055] Next, the second sealing portion 12 will be described in detail. Figure 5 This is a partial perspective view of the rib and its surroundings as viewed from above in the first direction D1. Figure 6 This is a partial perspective view of the rib and its surroundings as viewed from the lower side in the first direction D1. Figure 7 It is a plan view showing the rib and its surroundings in an enlarged manner. Figure 8 It is a side view showing the rib and its surroundings in an enlarged manner. Fig. 9 is an enlarged cross-sectional view showing the rib and its surroundings. Figures 4 to 9 As shown, the outer seal 24 has an eave 60 and a rib 70. The eave 60 and the rib 70 are formed integrally with the side portion 25, the first extension portion 26, and the second extension portion 27 by, for example, injection molding of a resin. That is, the side portion 25, the first extension portion 26, the second extension portion 27, the eave 60, and the rib 70 are formed as one member by a single injection molding.

[0056] The eaves 60 have a function of preventing the liquid adhering to one terminal surface of the storage module 4 from flowing along the outer peripheral surface of the outer seal 24 to the other terminal surface side of the storage module 4, thereby preventing the positive terminal surface and the negative terminal surface of the storage module 4 from short-circuiting via the liquid, i.e., the so-called liquid short-circuiting. The liquid is, for example, electrolyte leaked from the inside of the storage module 4, condensed water from the outside of the storage module 4, etc. As described above, the gap on the outer peripheral surface 12r side of the second sealing portion 12 of the adjacent storage module 4 is sealed by the material E (refer to Figure 1 ) is buried, so there is little need to provide the eaves 60 on the outer peripheral surface 12r of each storage module 4. Therefore, in the storage module 4, the eaves 60 is provided only on the outer peripheral surface 12s among the outer peripheral surfaces 12s and 12r of the second sealing portion 12. The eaves 60 is an elongated plate-like protrusion that is integrated with the side surface portion 25 and extends in the second direction D2.

[0057] The eaves 60 extends from the outer surface of the side portion 25 constituting the outer peripheral surface 12s to the outside of the electrode stack 11. The eaves 60 extends in the second direction D2 along the outer peripheral surface 12s. The side portion 25 has a connecting portion 25a, a first side portion 25b, and a second side portion 25c. The eaves 60 is connected to the connecting portion 25a. The connecting portion 25a is provided at the center portion of the side surface 11c in the first direction D1. The first side portion 25b is located between the connecting portion 25a and the first extension portion 26, and connects the connecting portion 25a to the first extension portion 26. The second side portion 25c is located between the connecting portion 25a and the second extension portion 27, and connects the connecting portion 25a to the second extension portion 27.

[0058] In the direction (third direction D3) orthogonal to the side surface 11c, the thickness t2 of the second side surface portion 25c is thicker than the thickness t1 of the first side surface portion 25b (t2>t1). In the present embodiment, the thickness t1 of the first side surface portion 25b is constant in the entire second direction D2 of the first side surface portion 25b, but it may not be constant. In addition, the thickness t2 of the second side surface portion 25c is constant in the entire second direction D2 of the second side surface portion 25c, but it may not be constant. In the case where the thickness t1 of the first side surface portion 25b and the thickness t2 of the second side surface portion 25c are not constant, it is sufficient that at least the average value of the thickness t2 of the second side surface portion 25c is greater than the average value of the thickness t1 of the first side surface portion 25b. For example, the minimum value of the thickness t2 of the second side surface portion 25c may be greater than the maximum value of the thickness t1 of the first side surface portion 25b.

[0059] The second side surface portion 25c has a thick portion 25d at a position facing the rib 70 across the eaves 60 in the first direction D1. The thick portion 25d is a portion that bulges toward the outside of the electrode stack 11. The thick portion 25d is provided so as to contact the eaves 60.

[0060] The eaves 60 includes a base end portion 61, an inclined portion 62, and a top end portion 63. The base end portion 61 is connected to the side portion 25. The base end portion 61 protrudes from the outer peripheral surface 12s in a direction (third direction D3) perpendicular to the outer peripheral surface 12s. The upper surface 61s of the base end portion 61 is set as a flat surface (horizontal surface) extending along the second direction D2 and the third direction D3. The upper surface 61s is a surface facing upward in the first direction D1. The upper surface 61s is adjacent to the first side portion 25b and is continuous with the first side portion 25b.

[0061] The inclined portion 62 connects the base end portion 61 and the top end portion 63. The inclined portion 62 is inclined relative to the third direction D3 in such a manner that the distance from the outer peripheral surface 12s gradually increases as it goes downward (vertically downward) in the first direction D1. Thus, the upper surface 62s of the inclined portion 62 is set as an inclined surface that is inclined in such a manner that it is farther away from the outer peripheral surface 12s as it goes downward in the first direction D1. The upper surface 62s is a surface facing upward in the first direction D1. The upper surface 62s is adjacent to the upper surface 61s and is continuous with the upper surface 61s.

[0062] The top end portion 63 extends from the top end of the inclined portion 62 in a manner that is inclined relative to the third direction D3 at an angle greater than the angle at which the inclined portion 62 is inclined relative to the third direction D3. As a result, the flow interruption property of the liquid flowing along the eaves 60 is improved. In addition, the top end portion 63 may extend downwardly from the top end of the inclined portion 62 in a manner that the distance from the outer peripheral surface 12s becomes approximately constant regardless of the position in the first direction D1. The top end (lower end) of the top end portion 63 is set at a position that does not protrude from the side surface portion 25 and the second extension portion 27 in the first direction D1.

[0063] The rib 70 is provided on the eave 60 to reinforce the eave 60. A plurality of ribs 70 are provided at predetermined intervals along the extension direction (the second direction D2) of the eave 60. The rib 70 has a plate-shaped main body 71 and a column 72. The main body 71 connects the eave 60 and the first side portion 25b. The main body 71 protrudes upward from the upper surface 61s of the base end portion 61 and the upper surface 62s of the inclined portion 62 in the first direction D1. The main body 71 is provided on the entirety of the upper surface 61s and the upper surface 62s in the direction (the third direction D3) orthogonal to the side surface 11c. The main body 71 is connected to the first side portion 25b at a position separated from the first extension portion 26 in the first direction D1.

[0064] The main body 71 includes a first main body portion 73 connected to the first side portion 25b and a second main body portion 74 connected to the column portion 72. The first main body portion 73 is provided on the upper surface 61s. The first main body portion 73 has a rectangular shape as viewed from the second direction D2. The first main body portion 73 is separated from the first extension portion 26 by a distance d1 (d1>0) in the first direction D1. The second main body portion 74 is provided on the upper surface 62s. The second main body portion 74 is connected to both sides of the column portion 72 in the third direction D3, and sandwiches the column portion 72 in the third direction D3.

[0065] The distance d1 between the first main body portion 73 and the first extension portion 26 in the stacking direction is longer than the distance d2 between the second main body portion 74 and the first extension portion 26 in the stacking direction (d1>d2). Thus, a step is formed between the first main body portion 73 and the second main body portion 74. The step includes an inclined surface. It can also be said that a cutout is provided in the portion of the main body portion 71 adjacent to the first side portion 25b. In addition, Figure 5 In the figure, a cutout 74a is also provided at the upper end of the second main body portion 74 on the opposite side to the first main body portion 73, but the cutout 74a is a structure provided, for example, due to the characteristics of the manufacturing device and is not a necessary structure of the main body portion 71.

[0066] The pillar portion 72 protrudes upward from the upper surface 62s of the inclined portion 62 in the first direction D1. The top end (upper end) of the pillar portion 72 is set at a position that does not protrude from the first extension portion 26 in the first direction D1. The pillar portion 72 has a cylindrical shape with a circular cross section. The pillar portion 72 is provided at the center portion of the upper surface 62s in the third direction D3. The pillar portion 72 cuts off the second main body portion 74 of the main body portion 71 in the direction (third direction D3) orthogonal to the side surface 11c. The pillar portion 72 is thicker than the main body portion 71 in the direction (second direction D2) orthogonal to the stacking direction (first direction D1) and parallel to the side surface 11c. The pillar portion 72 protrudes upward than the main body portion 71 in the first direction D1.

[0067] On the upper surface of the first extension portion 26, a protrusion 26a protruding upward is provided at a position corresponding to the rib 70. On the lower surface of the second extension portion 27, a protrusion 27a protruding downward is provided at a position corresponding to the rib 70. In the power storage device 1, the power storage modules 4 adjacent to each other in the first direction D1 are arranged so that the protrusions 26a and the protrusions 27a face each other in the first direction D1. Even when the power storage modules 4 expand, the gaps between the power storage modules 4 can be ensured by making the protrusions 26a and the protrusions 27a contact each other.

[0068] Next, a method for forming the second sealing portion 12 will be described. Fig.10 This is a cross-sectional view for explaining the inner seal forming process. Fig.11 This is a cross-sectional view for explaining the outer seal forming step.

[0069] like Fig.10 As shown, in the inner seal 23 (refer to Fig. 9), the inner seal 23 is formed along the side surface 11c using a pair of molds 55 and 56 that are configured to be able to contact and separate from each other in the first direction D1. When the pair of molds 55 and 56 are in contact with each other (mold closed state), a space for arranging the electrode stack 11 and a space for forming the inner seal 23 are provided inside the pair of molds 55 and 56.

[0070] The electrode stack 11 is arranged so that the first end face 11a and the second end face 11b are pressed against the molds 55 and 56 as a whole. The electrode stack 11 is given a compressive force in the first direction D1 by the pair of molds 55 and 56. In this state, the resin constituting the inner seal 23 is injected into the pair of molds 55 and 56 in a molten state from, for example, the injection port H1 (resin injection gate) provided in a manner opposite to the side surface 11c. As a result, the third portion 21c (see Figure 3 ) is covered by the inner seal 23.

[0071] like Fig.11 As shown, the outer seal 24 (refer to Fig. 9 ), a pair of molds 57, 58 configured to be contactable and separable from each other in the first direction D1 are used to form the side surface portion 25 along the inner seal 23, and to form the first extension portion 26 extending from the side surface portion 25 to the first end surface 11a and the second extension portion 27 extending from the side surface portion 25 to the second end surface 11b. When the pair of molds 57, 58 are in contact with each other (mold closed state), a space for arranging the electrode stack 11 in a state where the inner seal 23 is provided and a space for forming the outer seal 24 are provided inside the pair of molds 57, 58.

[0072] The resin constituting the outer seal 24 is injected into the pair of molds 57 and 58 in a molten state from, for example, the injection port H2 (resin injection gate) provided in the formation space of the column portion 72. As a result, the inner seal 23 is covered by the outer seal 24. Since the outer edge of the electrode stack 11 and the inner seal 23 are not in contact with the pair of molds 57 and 58, the outer edge of the electrode stack 11 and the inner seal 23 may be deformed due to the injection pressure of the resin. As a result, there is a possibility that the outer edge of the electrode stack 11 and the inner seal 23 may be deviated in position in the first direction D1, and the wall thickness may vary between the first extension 26 and the second extension 27. In the power storage module 4, the amount of resin flowing in between the first extension 26 and the second extension 27 is not likely to vary. Therefore, it is possible to suppress the position of the outer edge of the electrode stack 11 and the inner seal 23 from deviating in the first direction D1 in the pair of molds 57 and 58. The reason is described below.

[0073] The rib 70 is connected to the eaves 60 and the first side portion 25b of the side portion 25. When the rib 70 is used as an injection port for resin injection molding, in the resin path from the rib 70 to the first side portion 25b, there is a path that passes through the eaves 60 and there is a path that directly connects the rib 70 and the first side portion 25b without passing through the eaves 60. In contrast, in the resin path from the rib 70 to the second side portion 25c of the side portion 25, there is only a path that passes through the eaves 60. Therefore, the resin injected from the rib 70 flows more easily into the first side portion 25b than into the second side portion 25c.

[0074] The thickness t2 of the second side portion 25c is thicker than the thickness t1 of the first side portion 25b (t2>t1). That is, the flow path area of ​​the resin in the flow direction of the second side portion 25c is wider than the flow path area of ​​the resin in the flow direction of the first side portion 25b. Therefore, the resin flows more easily in the second side portion 25c than in the first side portion 25b. In contrast, since the first side portion 25b is connected to the rib 70 as described above, the resin flows more easily into it than in the second side portion 25c. Therefore, the resin flowing into the portion forming the first extension 26 and the second extension 27 is less likely to deviate. As a result, the position of the outer edge portion of the electrode stack 11 and the inner seal 23 is suppressed from deviating in the first direction D1 in the pair of molds 57 and 58.

[0075] In addition, the rib 70 has a column 72 that is separated from the first side portion 25b and protrudes from the eaves 60 in addition to the plate-like main body 71. Since the column 72 is thicker than the main body 71, when the column 72 is used as an injection port for resin injection molding, the resin easily flows into the eaves 60, and the resin can be promoted to flow from the eaves 60 into the side portion 25. In other words, since the main body 71 is thinner than the column 72, the amount of resin flowing through the main body 71 can be limited. Thus, the amount of resin that flows directly from the rib 70 to the first side portion 25b without passing through the eaves 60 can be limited. That is, in the present embodiment in which the column 72 is provided on the rib 70, the deviation of the amount of resin flowing into the first side portion 25b and the second side portion 25c is suppressed, compared with the case in which the column 72 is not provided on the rib 70. Therefore, the resin flowing into the first extension 26 located downstream of the first side surface portion 25b and the second extension 27 located downstream of the second side surface portion 25c is less likely to be uneven, and the positions of the outer edge of the electrode stack 11 and the inner seal 23 are suppressed from being deviated in the first direction D1 in the pair of dies 57 and 58. As a result, the wall thickness deviation between the first extension 26 and the second extension 27 can be suppressed. As a result, the strength of the power storage module 4 can be ensured.

[0076] The rib 70 includes the column portion 72 which is thicker than the main body portion 71. This can improve the strength of the rib 70. Therefore, even if the main body portion 71 is made thinner, the strength of the rib 70 can be maintained.

[0077] The second side surface portion 25c has a thick wall portion 25d at a position opposite to the rib 70 across the eaves 60 in the first direction D1. Therefore, it is possible to reliably realize a configuration in which the second side surface portion 25c is thicker than the first side surface portion 25b near the rib 70 where the resin flows in. According to the thick wall portion 25d, even if the thickness of the portion of the second side surface portion 25c other than the thick wall portion 25d is set equal to the thickness of the first side surface portion 25b, the average value of the thickness of the second side surface portion 25c can be made larger than the average value of the thickness of the first side surface portion 25b.

[0078] The main body portion 71 is connected to the first side surface portion 25b at a position separated from the first extension portion 26 in the first direction D1. That is, a predetermined separation distance (distance d1) is provided between the first extension portion 26 and the first main body portion 73 in the stacking direction. Therefore, compared with the case where the first extension portion 26 and the first main body portion 73 are provided at the same position in the stacking direction, the flow distance of the resin from the rib 70 to the first extension portion 26 becomes longer. As a result, the occurrence of deviation in wall thickness between the first extension portion 26 and the second extension portion 27 can be further suppressed.

[0079] As mentioned above, although the form of an example of this disclosure was described in detail, this disclosure is not limited to the above form.

[0080] For example, in the above-described embodiment, the power storage device 1 includes a plurality of power storage modules 4 stacked along the first direction D1. However, the number of power storage modules 4 in the power storage device 1 is arbitrary, and may be, for example, one.

[0081] In the power storage module 4, the rib 70 may not have the column portion 72. Even in this case, since the second side surface portion 25c is thicker than the first side surface portion 25b, it is possible to suppress the occurrence of thickness variation between the first extension portion 26 and the second extension portion 27.

[0082] In the power storage module 4 , the second side surface portion 25 c may have the same thickness as the first side surface portion 25 b . Even in this case, since the rib 70 includes the column portion 72 which is thicker than the main body portion 71 , the thickness variation between the first extension portion 26 and the second extension portion 27 can be suppressed.

[0083] The second side surface portion 25c may not have the thick wall portion 25d. Even in this case, for example, as long as the minimum value of the thickness of the second side surface portion 25c is greater than the maximum value of the thickness of the first side surface portion 25b, the average value of the thickness of the second side surface portion 25c will be greater than the average value of the thickness of the first side surface portion 25b.

[0084] The column portion 72 is not limited to a circular cross-section, and may also be a rectangular cross-section, an elliptical cross-section, or the like.

Claims

1. A power storage module, characterized in that: have: an electrode stack including a plurality of stacked electrodes; and a sealing member provided around the electrode stack so as to seal between the electrodes, The electrode stack has: a first end face and a second end face in a stacking direction of the plurality of electrodes; and a side face extending in the stacking direction in a manner connecting the first end face and the second end face, The seal has: a side portion disposed on the side surface; a first extension portion extending from the side portion to the first end surface; a second extension portion extending from the side portion to the second end surface; an eave extending from the side surface portion toward the outside of the electrode stack; and ribs, which are provided on the eaves, The side portion includes: a connection portion connected to the eaves; a first side portion located between the connection portion and the first extension portion; and a second side portion located between the connection portion and the second extension portion. The rib connects the eaves to the first side portion. The second side surface portion is thicker than the first side surface portion in a direction perpendicular to the side surface.

2. The power storage module according to claim 1, wherein: The second side surface portion has a thick wall portion at a position facing the rib across the eaves in the stacking direction.

3. The power storage module according to claim 1 or 2, wherein: The rib has a plate-shaped main body portion connecting the eaves and the first side portion, and a column portion separated from the side portion and protruding from the eaves in the stacking direction. The column portion is thicker than the body portion in a direction perpendicular to the stacking direction and parallel to the side surface.

4. The power storage module according to claim 3, wherein: The main body portion is connected to the first side surface portion at a position spaced apart from the first extension portion in the stacking direction.

5. The power storage module according to claim 4, wherein: The main body portion includes: a first main body portion connected to the first side portion; and a second main body portion connected to the column portion. The first main body portion is spaced apart from the first extending portion in the stacking direction by a distance longer than a distance between the second main body portion and the first extending portion in the stacking direction.

6. A power storage module, characterized in that: have: an electrode stack including a plurality of electrodes stacked along a stacking direction; and a sealing member provided around the electrode stack so as to seal between the electrodes, The electrode stack has: a first end face and a second end face in the stacking direction; and a side face extending in the stacking direction in a manner connecting the first end face and the second end face. The seal has: a side portion disposed on the side surface; a first extension portion extending from the side portion to the first end surface; a second extension portion extending from the side portion to the second end surface; an eave extending from the side surface portion toward the outside of the electrode stack; and ribs, which are provided on the eaves, The side portion includes: a connection portion connected to the eaves; a first side portion located between the connection portion and the first extension portion; and a second side portion located between the connection portion and the second extension portion. The rib has: a plate-shaped main body portion connecting the eaves and the first side portion; and a column portion which is separated from the first side portion and protrudes from the eaves in the stacking direction, The column portion is thicker than the body portion in a direction perpendicular to the stacking direction and parallel to the side surface.

7. The power storage module according to claim 6, wherein: The main body portion is connected to the first side surface portion at a position spaced apart from the first extension portion in the stacking direction.

8. The power storage module according to claim 7, wherein: The main body portion includes: a first main body portion connected to the first side portion; and a second main body portion connected to the column portion. The first main body portion is spaced apart from the first extending portion in the stacking direction by a distance longer than a distance between the second main body portion and the first extending portion in the stacking direction.

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