JP7132871B2 - storage module - Google Patents

Description

The present disclosure relates to power storage modules.

As a conventional power storage module, there is a bipolar battery including a bipolar electrode in which a positive electrode is formed on one side of a metal plate and a negative electrode is formed on the other side (see Patent Document 1). A bipolar battery has a laminate formed by laminating a plurality of bipolar electrodes with separators interposed therebetween. A sealing body is provided on the side surface of the laminate for sealing between the bipolar electrodes adjacent to each other in the stacking direction, and the internal space formed between the bipolar electrodes contains an electrolytic solution.

JP 2011-204386 A

The encapsulant has, for example, a resin portion coupled to the edge of each metal plate that constitutes the bipolar electrode. In order to increase the bonding strength between the metal plate and the resin portion, it is conceivable to form fine protrusion-like plating on the surface of the metal plate formed of a steel plate or the like. By using a plated steel sheet on which fine projections are formed, an anchor effect is produced by the projections, and the bonding strength between the metal plate and the resin portion is improved.

The step of plating the steel sheet includes washing the plated steel sheet with an acid after the formation of the plating. Therefore, if acid remains in the plated steel sheet after washing and if the plated steel sheet has defects (parts where plating is not formed), the steel sheet may rust. When the rusted steel sheet is exposed to the atmosphere, the rust progresses, which may cause problems such as a decrease in pressure resistance of the metal sheet and leakage of electrolyte.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide an electricity storage module that can suppress the occurrence and progression of rust on a metal plate.

A power storage module according to one aspect of the present disclosure includes an electrode laminate formed by stacking metal plates that form electrodes including a plurality of bipolar electrodes, and an internal space is formed between adjacent electrodes in the electrode laminate in the stacking direction. and a sealing body for sealing the internal space, wherein the cooling plate abuts against the metal plate located in the outermost layer in the electrode laminate, and the ionization tendency of the material constituting the cooling plate is reduced to the outermost layer is larger than the ionization tendency of the metal plate located at .

In this power storage module, the ionization tendency of the material forming the cooling plate is greater than the ionization tendency of the metal plate located in the outermost layer. Therefore, a sacrificial anti-corrosion effect based on the difference in ionization tendency is produced between the metal plate located in the outermost layer and the cooling plate. Due to the sacrificial anti-corrosion effect, the progress of rust on the cooling plate precedes the progress of rust on the metal plate. Therefore, it is possible to suppress the occurrence and progression of rust on the metal plate, thereby preventing problems such as a decrease in pressure resistance of the metal plate and leakage of electrolyte.

The material constituting the cooling plate may be aluminum or zinc. In this case, a sufficient difference in ionization tendency can be ensured with respect to the metal plate. Also, the cooling plate can be provided with electrical conductivity in addition to a sufficient cooling function.

The metal plate is a plated steel plate having a steel plate, a base plating layer provided on the surface of the steel plate, and a plurality of protruding platings provided on the surface of the base plating layer, and the material constituting the cooling plate is ionized. The tendency may be greater than the ionization tendency of the steel sheet forming the outermost metal sheet. In this case, the formation of the projecting plating can improve the bonding strength when the metal plate is bonded to another resin portion or the like by the anchor effect. Further, since the ionization tendency of the material forming the cooling plate is higher than that of the steel sheet, the occurrence and progression of rust on the metal plate can be suppressed.

The thickness of the cooling plate may be greater than the thickness of the steel plate. In this case, the sacrificial anti-corrosion effect of the cooling plate can be maintained for a long period of time. Therefore, the occurrence and progress of rust on the metal plate can be more sufficiently suppressed.

The thickness of the base plating layer of the metal plate positioned as the outermost layer may be greater than the thickness of the base plating layer of the metal plate positioned as the intermediate layer. When forming a coating on a steel sheet, for example, if air bubbles due to gas or the like adhere to the surface of the steel sheet, the plating may not be sufficiently formed around the air bubbles, and defects may occur in the plated steel sheet. As the plating thickness increases, air bubbles tend to be less likely to adhere, and there is an inversely proportional relationship between the plating thickness and the defect area. Therefore, by ensuring the thickness of the underlying plating layer, it is possible to suppress the occurrence of plating defects in the outermost metal plate. As a result, the occurrence and progression of rust on the metal plate can be suppressed more reliably. In addition, since the thickness of the underlying plating layer of the metal plate located in the intermediate layer can be reduced, the amount of plating used in the electrode laminate can be reduced.

ADVANTAGE OF THE INVENTION According to this indication, generation|occurrence|production and progress of rust in a metal plate can be suppressed.

1 is a schematic cross-sectional view showing a power storage device including power storage modules according to an embodiment; FIG. FIG. 3 is a schematic cross-sectional view showing the internal configuration of the power storage module; 4 is an enlarged cross-sectional view of a main part showing the configuration of an electrode plate; FIG. FIG. 4 is a schematic cross-sectional view showing how rust is generated due to plating defects. It is a graph which shows the relationship between plating thickness and a plating defect area.

Hereinafter, preferred embodiments of a power storage module according to one aspect of the present disclosure will be described in detail with reference to the drawings.

Hereinafter, preferred embodiments of a power storage module according to one aspect of the present disclosure will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing one embodiment of a power storage device. A power storage device 1 shown in FIG. 1 is used, for example, 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 stacked power storage modules 4 and a restraining member 3 that applies a restraining load to the module stack 2 in the stacking direction D of the module stack 2 . .

The module stack 2 includes a plurality (here, three) of power storage modules 4 and a plurality (here, four) of cooling plates 5 . The power storage module 4 is a bipolar battery and has a rectangular shape when viewed from the stacking direction D. As shown in FIG. The storage module 4 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-metal hydride secondary battery is exemplified.

Energy storage modules 4 adjacent to each other in the stacking direction D are electrically connected via cooling plates 5 . The cooling plates 5 are arranged between the power storage modules 4 adjacent to each other in the stacking direction D and outside the power storage modules 4 positioned at the stack end. A positive electrode terminal 6 is connected to one of the cooling plates 5 arranged outside the power storage module 4 positioned at the end of the stack. A negative electrode terminal 7 is connected to the other cooling plate 5 arranged outside the power storage module 4 positioned at the end of the stack. The positive terminal 6 and the negative terminal 7 are pulled out in a direction crossing the stacking direction D, for example, from the edge of the cooling plate 5 . The power storage device 1 is charged and discharged by the positive terminal 6 and the negative terminal 7 .

Inside the cooling plate 5, a plurality of flow paths 5a for circulating a coolant such as air are provided. The channel 5a extends along a direction that intersects (perpendicularly) the stacking direction D and the lead-out direction of the positive electrode terminal 6 and the negative electrode terminal 7, for example. The cooling plate 5 has a function of dissipating heat generated in the power storage module 4 by circulating a coolant through the flow path 5a. Moreover, the cooling plate 5 also has a function as a connecting member that electrically connects the power storage modules 4 to each other. In the example of FIG. 1, the area of the cooling plate 5 when viewed from the stacking direction D is smaller than the area of the storage module 4, but from the viewpoint of improving heat dissipation, the area of the cooling plate 5 is less than the area of the storage module 4. , or may be larger than the area of the power storage module 4 .

The restraining member 3 includes a pair of end plates 8 sandwiching the module stack 2 in the stacking direction D, and fastening bolts 9 and nuts 10 fastening the end plates 8 together. The end plate 8 is a rectangular metal plate having an area slightly larger than the area of the power storage module 4 and the cooling plate 5 when viewed in the stacking direction D. As shown in FIG. A film F having electrical insulation is provided on the surface of the end plate 8 on the module laminate 2 side. The film F insulates between the end plate 8 and the cooling plate 5 .

An insertion hole 8 a is provided in the edge of the end plate 8 at a position outside the module stack 2 . The fastening bolt 9 is passed from the insertion hole 8a of one end plate 8 toward the insertion hole 8a of the other end plate 8. As shown in FIG. A nut 10 is screwed onto the tip portion of the fastening bolt 9 protruding from the insertion hole 8a of the other end plate 8 . As a result, the storage module 4 and the cooling plate 5 are sandwiched between the end plates 8 and unitized as the module laminate 2 . A binding load is applied in the stacking direction D to the module stack 2 .

Next, the configuration of the power storage module 4 will be described in detail. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module shown in FIG. 1. FIG. As shown in FIG. 2 , the power storage module 4 includes an electrode laminate 11 and a resin sealing body 12 that seals the electrode laminate 11 . The electrode stack 11 is composed of a plurality of electrodes stacked along the stacking direction D of the storage module 4 with separators 13 interposed therebetween. These electrodes include a stack of multiple bipolar electrodes 14 , a negative terminal electrode 18 and a positive terminal electrode 19 .

The bipolar electrode 14 includes an electrode plate (metal plate) 15 including one surface 15a and the other surface 15b opposite to the one surface 15a, a positive electrode 16 provided on the one surface 15a, and a negative electrode 17 provided on the other surface 15b. and The positive electrode 16 is a positive electrode active material layer formed by coating the electrode plate 15 with a positive electrode active material. The negative electrode 17 is a negative electrode active material layer formed by coating the electrode plate 15 with a negative electrode active material. In the electrode laminate 11 , the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of another bipolar electrode 14 adjacent to one side in the stacking direction D with the separator 13 interposed therebetween. In the electrode laminate 11 , the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of another bipolar electrode 14 adjacent to the other in the stacking direction D with the separator 13 interposed therebetween.

The negative terminal electrode 18 has an electrode plate 15 and a negative electrode 17 provided on the other surface 15 b of the electrode plate 15 . The negative terminal electrode 18 is arranged at one end in the stacking direction D so that the other surface 15b faces the central side in the stacking direction D of the electrode stack 11 . One surface 15 a of the electrode plate 15 of the negative terminal electrode 18 forms one outer surface in the stacking direction D of the electrode stack 11 and is electrically connected to one cooling plate 5 (see FIG. 1 ) adjacent to the power storage module 4 . It is connected to the. The negative electrode 17 provided on the other surface 15b of the electrode plate 15 of the negative terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D with the separator 13 interposed therebetween.

The positive terminal electrode 19 has an electrode plate 15 and a positive electrode 16 provided on one surface 15 a of the electrode plate 15 . The positive terminal electrode 19 is arranged at the other end in the stacking direction D so that one surface 15 a faces the central side in the stacking direction D of the electrode stack 11 . The positive electrode 16 provided on one surface 15a of the positive terminal electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D with the separator 13 interposed therebetween. The other surface 15b of the electrode plate 15 of the positive terminal electrode 19 constitutes the other outer surface in the stacking direction D of the electrode laminate 11, and is electrically connected to the other cooling plate 5 (see FIG. 1) adjacent to the power storage module 4. It is connected to the.

The electrode plate 15 is made of a metal plate such as a plated nickel plate or a plated steel plate. Here, the electrode plate 15 is made of a plated steel plate obtained by plating the surface of the steel plate with nickel. Steel sheets that serve as base materials for plated steel sheets include, for example, ordinary steels such as rolled steels, and special steels such as stainless steels. The edge portion 15c of the electrode plate 15 has a rectangular frame shape and is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. Examples of the positive electrode active material forming the positive electrode 16 include nickel hydroxide. Examples of negative electrode active materials that constitute the negative electrode 17 include hydrogen storage alloys. In this embodiment, the formation area of the negative electrode 17 on the other surface 15 b of the electrode plate 15 is one size larger than the formation area of the positive electrode 16 on the one surface 15 a of the electrode plate 15 .

The separator 13 is formed in a sheet shape, for example. 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, methyl cellulose, and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound.

The sealing body 12 is made of, for example, an insulating resin, and is formed into a rectangular tubular shape as a whole. The sealing body 12 is provided on the side surface 11 a of the electrode laminate 11 so as to surround the edge 15 c of the electrode plate 15 . The encapsulant 12 holds the edge 15c on the side surface 11a. The sealing body 12 includes a plurality of first sealing portions (resin portions) 21 coupled to the edge portion 15c of the electrode plate 15, and surrounds the first sealing portions 21 from the outside along the side surface 11a. and a second sealing portion 22 coupled to each of the sealing portions 21 . The first sealing portion 21 and the second sealing portion 22 are, for example, an insulating resin having alkali resistance. Examples of materials constituting the first sealing portion 21 and the second sealing portion 22 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like.

The first sealing portion 21 is provided continuously over the entire circumference of the edge portion 15c on the one surface 15a of the electrode plate 15, and has a rectangular frame shape when viewed from the stacking direction D. As shown in FIG. In this embodiment, the first sealing portion 21 is provided not only for the electrode plate 15 of the bipolar electrode 14 but also for the electrode plate 15 of the negative terminal electrode 18 and the electrode plate 15 of the positive terminal electrode 19 . In the negative terminal electrode 18, the first sealing portion 21 is provided on the edge 15c of the one surface 15a of the electrode plate 15. In the positive terminal electrode 19, the edges of both the one surface 15a and the other surface 15b of the electrode plate 15 are provided. A first sealing portion 21 is provided at 15c.

The first sealing portion 21 is welded to the one surface 15a of the electrode plate 15 by, for example, ultrasonic waves or thermocompression, and is airtightly joined. The first sealing portion 21 is a film having a predetermined thickness in the stacking direction D, for example. The inside of the first sealing portion 21 is positioned between the edge portions 15c of the electrode plates 15 adjacent to each other in the stacking direction D. As shown in FIG. The outer side of the first sealing portion 21 protrudes beyond the edge of the electrode plate 15 , and the tip portion thereof is held by the second sealing portion 22 . The first sealing portions 21 adjacent to each other along the stacking direction D may be separated from each other or may be in contact with each other. Further, the outer edge portions of the first sealing portion 21 may be joined together by, for example, hot plate welding.

The second sealing portion 22 is provided outside the electrode laminate 11 and the first sealing portion 21 and constitutes an outer wall (housing) of the power storage module 4 . The second sealing portion 22 is formed, for example, by injection molding of resin, and extends along the stacking direction D over the entire length of the electrode stack 11 . The second sealing portion 22 has a rectangular frame shape extending in the stacking direction D as an axial direction. The second sealing portion 22 is welded to the outer surface of the first sealing portion 21 by heat during injection molding, for example.

The first sealing portion 21 and the second sealing portion 22 form an internal space V between adjacent electrodes and seal the internal space V. As shown in FIG. More specifically, the second sealing portion 22 , together with the first sealing portion 21 , is arranged between the bipolar electrodes 14 adjacent to each other along the stacking direction D and between the negative electrode termination electrodes 18 adjacent to each other along the stacking direction D. and the bipolar electrode 14, and between the positive terminal electrode 19 and the bipolar electrode 14 adjacent to each other along the stacking direction D, respectively. As a result, airtight internal spaces V are formed between the adjacent 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. ing. The internal space V accommodates a water-based electrolytic solution (not shown) containing an alkaline solution such as an aqueous potassium hydroxide solution. The electrolytic solution is impregnated in the separator 13 , the positive electrode 16 and the negative electrode 17 .

Next, the configuration of the electrode plate 15 described above will be described in more detail.

FIG. 3 is an enlarged cross-sectional view of a main part showing the configuration of the electrode plate. As shown in the figure, a region where the electrode plate 15 and the first sealing portion 21 overlap is a bonding region K between the electrode plate 15 and the first sealing portion 21 . In the coupling area K, the surface of the electrode plate 15 is roughened. On the surface of the electrode plate 15, only the bonding region K may be roughened. Roughened.

Specifically, the electrode plate 15 is made of a plated steel plate having a steel plate 31, a base plating layer 32 provided on the surface of the steel plate 31, and a plurality of projecting platings 33 provided on the surface of the base plating layer 32. It is configured. The steel plate 31 is the base material of the electrode plate 15 . The material of the underlying plating layer 32 and the protruding plating 33 are both nickel. The base plating layer 32 is a layer for flattening the surface of the steel plate 31 and is formed so as to cover the steel plate 31 .

The protruding plating 33 has, for example, a protruding portion 33a formed on the base plating layer 32 as a base end, and has a thickened portion 33b on the tip end side of the protruding portion 33a. At the bonding interface between the electrode plate 15 and the first sealing portion 21, the molten resin enters between the plurality of protrusions formed by surface roughening due to the plurality of protruding platings 33, thereby exerting an anchor effect. Thereby, the bonding strength between the electrode plate 15 and the first sealing portion 21 can be improved. In addition, since the projecting plating 33 has an undercut shape, the anchor effect is improved.

The manufacture of the electrode plate 15 includes a step of plating the steel plate 31 . After forming the plating, a step of washing the plated steel sheet with acid to remove oxides adhering to the surface of the plated steel sheet is performed. After washing with acid, the plated steel sheet is washed with water to remove the acid from the surface of the plated steel sheet. However, even when washing with water, acid may remain on the surface of the plated steel sheet. In this case, as in the example shown in FIG. 4, if acid remains in the plated steel sheet after washing and plating defects (parts where plating is not formed) 34 are present in the plated steel sheet, the plating defects 34 Rust 35 may occur on the steel plate 31 in the vicinity. When the steel plate 31 with the rust 35 comes into contact with the air, the rust 35 advances into the steel plate 31 and may cause problems such as a decrease in pressure resistance of the electrode plate 15 and leakage of electrolyte.

On the other hand, in the electric storage module 4 , the cooling plate 5 is in contact with the electrode plate 15 located in the outermost layer of the electrode laminate 11 , and the ionization tendency of the material forming the cooling plate 5 affects the electrode plate 15 . is larger than the ionization tendency of the steel plate 31 which In the present embodiment, the electrode plate 15 forming the negative terminal electrode 18 and the electrode plate 15 forming the positive terminal electrode 19 correspond to metal plates positioned in the outermost layer. Further, the electrode plate 15 constituting the bipolar electrode 14 corresponds to the metal plate located in the intermediate layer.

The material of the steel plate 31 used for the electrode plate 15 is iron. On the other hand, the material of the cooling plate 5 in contact with the electrode plate 15 is, for example, aluminum or zinc. Aluminum or zinc has a greater tendency to ionize than iron. Therefore, between the steel plate 31 of the electrode plate 15 located in the outermost layer and the cooling plate 5, a sacrificial anti-corrosion effect is produced based on the difference in ionization tendency. Due to the sacrificial anti-corrosion effect, even if the plated steel sheet constituting the electrode plate 15 has a plating defect, the progress of rust on the cooling plate 5 precedes the progress of rust on the electrode plate 15 . Therefore, it is possible to suppress the occurrence and progression of rust on the electrode plate 15, thereby preventing problems such as a decrease in pressure resistance of the electrode plate 15 and leakage of electrolyte.

Further, in the storage module 4, the thickness H1 (see FIG. 1) of the cooling plate 5 is larger than the thickness H2 (see FIG. 3) of the steel plate 31 forming the electrode plate 15 located in the outermost layer. The thickness H1 of the cooling plate 5 is the total thickness including the flow path 5a, and is, for example, about 3 mm. The thickness H2 of the steel plate 31 is the thickness of the portion of the electrode plate 15 excluding the base plating layer 32 and the projecting plating 33, and is, for example, about 50 μm. The thickness H3 (see FIG. 1) of the plate-like portion of the cooling plate 5 excluding the flow paths 5a may be larger than the thickness H2 of the steel plate 31 (see FIG. 3). The thickness H3 of the plate-like portion is, for example, approximately 0.5 mm to 1.0 mm. According to these configurations, since the thickness of the cooling plate 5 is sufficiently ensured, the sacrificial anti-corrosion effect of the cooling plate 5 can be maintained for a long period of time. Therefore, the generation and progression of rust on the electrode plate 15 can be more sufficiently suppressed.

In the electric storage module 4, in the electrode laminate 11, the thickness of the underlying plating layer 32 of the electrode plate 15 located in the outermost layer is larger than the thickness of the underlying plating layer 32 of the electrode plate 15 located in the intermediate layer. ing. A certain correlation exists between plating thickness and plating defects. When forming a coating on a steel sheet, for example, if air bubbles due to gas or the like adhere to the surface of the steel sheet, the formation of the coating around the air bubbles becomes insufficient, which causes plating defects on the steel sheet. As the plating thickness increases, air bubbles tend to be less likely to adhere, and there is an inversely proportional relationship between the plating thickness and the defect area.

FIG. 5 is a graph showing the relationship between plating thickness and plating defect area. In the figure, the horizontal axis indicates the plating thickness, and the vertical axis indicates the plating defect area. The plating defect area is the ratio of the plating defect area to the plated area. As shown in FIG. 5, as the plating thickness increases, the plating defect area ratio decreases. For example, when the plating thickness is 1.0 μm, the plating defect area is approximately 0.1%, and when the plating thickness is 2.0 μm, the plating defect area is reduced to approximately 0.01%. The percentage of plating defect area is almost 0% in the range where the plating thickness is 4.0 μm or more.

In the electric storage module 4, the thickness of the underlying plating layer 32 of the electrode plate 15 located on the outermost layer is, for example, greater than 2.0 μm. The thickness of the underlying plating layer 32 of the electrode plate 15 positioned as the outermost layer is preferably 4.0 μm or more, more preferably 6.0 μm or more, from the viewpoint of suppressing the occurrence of plating defects. In addition, the thickness of the base plating layer 32 of the electrode plate 15 located in the outermost layer is preferably 10 μm or less from the viewpoint of reducing the amount of plating used. On the other hand, the thickness of the underlying plating layer 32 of the electrode plate 15 located in the intermediate layer is preferably 2.0 μm or less from the viewpoint of reducing the amount of plating used.

In the negative terminal electrode 18, one surface 15a of the electrode plate 15 is exposed to the atmosphere, and in the positive terminal electrode 19, the other surface 15b of the electrode plate 15 is exposed to the atmosphere. Therefore, in the negative terminal electrode 18, it is preferable that the thickness of the underlying plating layer 32 on at least the one surface 15a side of the electrode plate 15 satisfies the above range. It is preferable that the thickness of the underlying plating layer 32 on the surface 15b side satisfies the above range. The thickness of the base plating layer 32 in the electrode plate 15 is represented by the thickness in the normal direction of the surface of the steel plate 31 between the projecting platings 33, as indicated by symbol T in FIG. The thickness T of the underlying plating layer 32 can be measured, for example, by fluorescent X-rays.

As described above, in the electric storage module 4, the ionization tendency of the material forming the cooling plate 5 is higher than the ionization tendency of the steel plate 31 forming the electrode plate 15 located in the outermost layer. For this reason, a sacrificial anti-corrosion effect based on the difference in ionization tendency occurs between the steel plate 31 of the electrode plate 15 located in the outermost layer and the cooling plate 5 , and the progress of rust on the cooling plate 5 is suppressed by the rust on the electrode plate 15 . It is possible to precede the progress. Therefore, it is possible to suppress the occurrence and progression of rust on the electrode plate 15, thereby preventing problems such as a decrease in pressure resistance of the electrode plate 15 and leakage of electrolyte.

In this embodiment, the thickness T1 of the cooling plate 5 is larger than the thickness T2 of the steel plate 31 . As a result, the sacrificial anti-corrosion effect of the cooling plate 5 can be maintained for a long period of time. Since the material forming the cooling plate 5 is aluminum or zinc, a sufficient difference in ionization tendency can be ensured with respect to iron, which is the material of the steel plate 31 . Moreover, it is possible to provide the cooling plate 5 with a sufficient cooling function and electrical conductivity.

In the present embodiment, the thickness of the underlying plating layer 32 of the electrode plate 15 located in the outermost layer is larger than the thickness of the underlying plating layer 32 of the electrode plate 15 located in the intermediate layer. By ensuring the thickness of the underlying plating layer 32 , it is possible to suppress the occurrence of plating defects 34 in the outermost electrode plate 15 . As a result, the generation and progression of rust on the electrode plate 15 can be suppressed more reliably. In addition, since the thickness of the base plating layer 32 of the electrode plate 15 located in the intermediate layer is suppressed, the amount of plating used in the electrode laminate 11 is suppressed. Therefore, the manufacturing cost of the power storage module 4 can be reduced.

The present disclosure is not limited to the above embodiments. For example, in the above embodiment, the electrode plate 15 constituting the negative terminal electrode 18 and the electrode plate 15 constituting the positive terminal electrode 19 correspond to the electrode plate (metal plate) 15 located in the outermost layer. The configuration is not limited to this. For example, an uncoated electrode may be further laminated outside in the lamination direction D with respect to at least one of the negative terminal electrode 18 and the positive terminal electrode 19 . The uncoated electrode is composed of an electrode plate (metal plate) 15 having neither a positive electrode 16 nor a negative electrode 17 and is electrically connected to the adjacent terminating electrode. In this case, the ionization tendency of the material forming the cooling plate 5 should be higher than the ionization tendency of the steel sheet 31 forming the uncoated electrode.

Further, when an uncoated electrode is laminated as the outermost layer, if the thickness of the underlying plating layer 32 of the uncoated electrode is greater than the thickness of the underlying plating layer 32 of the electrode plate 15 located in the intermediate layer, good. The thickness of the underlying plating layer 32 of the electrode plate 15 of the negative terminal electrode 18 or the positive terminal electrode 19 located inside the uncoated electrode in the stacking direction D is equivalent to the thickness of the underlying plating layer 32 of the uncoated electrode. or equal to the thickness of the underlying plating layer 32 of the electrode plate 15 located in the intermediate layer. In the former case, it is possible to suppress the generation and progress of rust 35, and in the latter case, it is possible to suppress the amount of plating used.

4 power storage module, 5 cooling plate, 11 electrode laminate, 12 sealing body, 14 bipolar electrode, 15 electrode plate (metal plate), 31 steel plate, 32 base plating layer, 33 projecting shape Plating, D...Lamination direction, V...Internal space.

Claims (4)

an electrode laminate obtained by stacking metal plates constituting electrodes including a plurality of bipolar electrodes;
a sealing body that forms an internal space between the electrodes adjacent in the stacking direction in the electrode laminate and seals the internal space;
A cooling plate is in contact with the metal plate located in the outermost layer in the electrode laminate,
The metal sheet is a plated steel sheet having a steel sheet, a base plating layer provided on the surface of the steel sheet, and a plurality of projecting platings provided on the surface of the base plating layer,
The electricity storage module, wherein the ionization tendency of the material forming the cooling plate is greater than the ionization tendency of the steel plate forming the metal plate located in the outermost layer. 2. The electricity storage module according to claim 1, wherein the material forming said cooling plate is aluminum or zinc. 3. The power storage module according to claim 1 , wherein the thickness of the cooling plate is greater than the thickness of the steel plate. 4. The thickness of the underlying plating layer of the metal plate located in the outermost layer is larger than the thickness of the underlying plating layer of the metal plate located in the intermediate layer . A storage module as described.

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