JP2020140767A - Power storage module - Google Patents

Abstract

To provide a power storage module capable of preventing formation and progression of rust on a metal plate.SOLUTION: A power storage module includes an electrode laminate 11 laminating metal plates constituting an electrode including multiple bipolar electrodes 14, and an encapsulant 12 forming an internal space V between electrodes adjoining in the lamination direction D in the electrode laminate 11, and sealing the internal space V. An electrode plate (metal plate) 15 is a plated sheet steel having a steel sheet 31, a base plating layer 32 provided on the surface of the steel sheet 31, and multiple protrusion plating 33 provided on the surface of the base plating layer 32, where the thickness of the base plating layer 32 of the electrode plate 15 located on the outermost layer in the electrode laminate 11 is larger than the thickness of the base plating layer 32 of the electrode plate 15 located on the intermediate layer.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a power storage module.

As a conventional power storage module, there is a bipolar battery provided with a bipolar electrode having a positive electrode formed on one surface of a metal plate and a negative electrode formed on the other surface (see Patent Document 1). The bipolar battery includes a laminate formed by laminating a plurality of bipolar electrodes via a separator. On the side surface of the laminated body, a sealing body for sealing between the bipolar electrodes adjacent to each other in the stacking direction is provided, and the electrolytic solution is housed in the internal space formed between the bipolar electrodes.

Japanese Unexamined Patent Publication No. 2011-204386

The encapsulant has, for example, a resin portion bonded to the edge of each metal plate constituting 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-shaped plating on the surface of the metal plate formed of a steel plate or the like. By using a plated steel sheet having fine protrusions formed, an anchor effect is generated by the protrusions, and the bonding strength between the metal plate and the resin portion can be improved.

The step of plating the steel sheet includes a step of cleaning the plated steel sheet with an acid after the formation of the plating. Therefore, if acid remains on the plated steel sheet after cleaning and defects (parts where plating is not formed) are present on the plated steel sheet, rust may occur on the steel sheet. When a rusted steel sheet comes into contact with the atmosphere, the rust progresses, which may cause problems such as a decrease in the pressure resistance of the metal plate and leakage of the electrolytic solution.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a power storage module capable of suppressing the generation and progress of rust on a metal plate.

The power storage module according to one aspect of the present disclosure forms an internal space between an electrode laminate in which metal plates constituting electrodes including a plurality of bipolar electrodes are laminated and electrodes adjacent to each other in the stacking direction in the electrode laminate. Along with this, a sealing body for sealing the internal space is provided, and the metal plate includes 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. The thickness of the base plating layer of the metal plate located at the outermost layer in the electrode laminate is larger than the thickness of the base plating layer of the metal plate located at the intermediate layer.

In this power storage module, the thickness of the base plating layer of the metal plate located on the outermost layer of the electrode laminate is sufficiently secured. When forming plating on a steel sheet, for example, if bubbles due to gas or the like adhere to the surface of the steel sheet, the formation of plating is insufficient around the bubbles, and defects may occur in the plated steel sheet. As the plating thickness increases, bubbles tend to be less likely to adhere, and there is an inversely proportional relationship between the plating thickness and the defect area. In this power storage module, by ensuring the thickness of the base plating layer, it is possible to suppress the occurrence of plating defects in the outermost metal plate. Therefore, even if the metal plate comes into contact with the atmosphere, it is possible to suppress the occurrence and progress of rust, and it is possible to prevent the occurrence of problems such as a decrease in the pressure resistance of the metal plate and leakage of the electrolytic solution. On the other hand, in this power storage module, the thickness of the base plating layer of the metal plate located in the intermediate layer can be suppressed. Therefore, it is possible to reduce the amount of plating used in the electrode laminate, and it is possible to reduce the manufacturing cost.

The thickness of the base plating layer of the metal plate located on the outermost layer may be larger than 2.0 μm. In this case, the thickness of the base plating layer can be sufficiently secured, and the occurrence of plating defects in the outermost metal plate can be more reliably suppressed.

The thickness of the base plating layer of the metal plate located on the outermost layer may be 10 μm or less. In this case, it is possible to avoid an excessive thickness of the base plating layer. Therefore, the manufacturing cost of the power storage module can be suppressed.

The thickness of the base plating layer of the metal plate located in the intermediate layer may be 2.0 μm or less. By reducing the thickness of the base plating layer of the metal plate located in the intermediate layer, it is possible to sufficiently reduce the amount of plating used in the electrode laminate, and the manufacturing cost can be further reduced.

The electrode laminate has a negative electrode terminal electrode on one end side in the stacking direction and a positive electrode terminal electrode on the other end side in the stacking direction, and the metal plate located in the outermost layer is a metal plate constituting the negative electrode terminal electrode and It may be a metal plate constituting the positive electrode terminal electrode. In this case, it is possible to suppress the occurrence of plating defects in the metal plates of the negative electrode terminal electrode and the positive electrode terminal electrode, which are the outermost layers.

According to the present disclosure, it is possible to suppress the generation and progress of rust on the metal plate.

It is schematic cross-sectional view which shows the power storage device configured with the power storage module which concerns on this embodiment. It is the schematic sectional drawing which shows the internal structure of the power storage module. It is an enlarged sectional view of the main part which shows the structure of an electrode plate. It is a schematic cross-sectional view which shows the state of the occurrence of rust by a plating defect. It is a graph which shows the relationship between the plating thickness and the plating defect area.

Hereinafter, preferred embodiments of the 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 an embodiment of a power storage device. The power storage device 1 shown in FIG. 1 is 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 stacked power storage modules 4, and a restraint member 3 that applies a restraining load to the module stack 2 in the stacking direction D of the module stack 2. ..

The module laminate 2 includes a plurality of (three in this case) power storage modules 4 and a plurality of (four in this case) conductive plates 5. The power storage module 4 is a bipolar battery and has a rectangular shape when viewed from the stacking direction D. The power 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 hydrogen secondary battery will be illustrated.

The power storage modules 4 adjacent to each other in the stacking direction D are electrically connected to each other via the conductive plate 5. The conductive 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 located at the stacking ends. A positive electrode terminal 6 is connected to one of the conductive plates 5 arranged outside the power storage module 4 located at the laminated end. The negative electrode terminal 7 is connected to the other conductive plate 5 arranged outside the power storage module 4 located at the laminated end. The positive electrode terminal 6 and the negative electrode terminal 7 are drawn out from the edge of the conductive plate 5, for example, in a direction intersecting the stacking direction D. The positive electrode terminal 6 and the negative electrode terminal 7 charge and discharge the power storage device 1.

Inside the conductive plate 5, a plurality of flow paths 5a through which a refrigerant such as air flows are provided. The flow path 5a extends along a direction that intersects (orthogonally), for example, the stacking direction D and the pull-out direction of the positive electrode terminal 6 and the negative electrode terminal 7. The conductive plate 5 has a function as a connecting member that electrically connects the power storage modules 4 to each other. Further, the conductive plate 5 also has a function as a heat radiating plate that dissipates heat generated by the power storage module 4 by circulating a refrigerant through these flow paths 5a. In the example of FIG. 1, the area of the conductive plate 5 seen from the stacking direction D is smaller than the area of the power storage module 4, but from the viewpoint of improving heat dissipation, the area of the conductive plate 5 is the power storage module 4. It may be the same as the area of the power storage module 4 and may be larger than the area of the power storage module 4.

The restraint member 3 is composed of a pair of end plates 8 that sandwich the module laminate 2 in the stacking direction D, and fastening bolts 9 and nuts 10 that fasten the end plates 8 to each other. The end plate 8 is a rectangular metal plate having an area one size larger than the area of the power storage module 4 and the conductive plate 5 as viewed from the stacking direction D. 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 conductive plate 5.

An insertion hole 8a is provided at the edge of the end plate 8 at a position outside the module laminate 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. A nut 10 is screwed into the tip portion of the fastening bolt 9 protruding from the insertion hole 8a of the other end plate 8. As a result, the power storage module 4 and the conductive plate 5 are sandwiched by the end plates 8 and unitized as the module laminate 2. Further, a restraining load is applied to the module laminated body 2 in the laminating direction D.

Next, the configuration of the power storage module 4 will be described in detail. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module shown in FIG. As shown in FIG. 2, the power storage module 4 includes an electrode laminate 11 and a resin sealant 12 that seals the electrode laminate 11. The electrode laminate 11 is composed of a plurality of electrodes laminated along the stacking direction D of the power storage module 4 via the separator 13. These electrodes include a laminate of a plurality of bipolar electrodes 14, a negative electrode termination electrode 18, and a positive electrode termination electrode 19.

The bipolar electrode 14 includes an electrode plate (metal plate) 15 including one surface 15a and the other surface 15b on the opposite side of 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 have. The positive electrode 16 is a positive electrode active material layer formed by coating the electrode plate 15 with the positive electrode active material. The negative electrode 17 is a negative electrode active material layer formed by applying the negative electrode active material to the electrode plate 15. 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 of the stacking directions 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 electrode terminal electrode 18 has an electrode plate 15 and a negative electrode 17 provided on the other surface 15b of the electrode plate 15. The negative electrode terminal electrode 18 is arranged at one end of the stacking direction D so that the other surface 15b faces the center side of the stacking direction D in the electrode laminated body 11. One surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18 constitutes one outer surface of the electrode laminate 11 in the stacking direction D, and is electrically connected to one conductive 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 electrode terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D via the separator 13.

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

The electrode plate 15 is made of, for example, a metal plate such as a nickel plate whose surface is plated or a steel plate whose surface is plated. Here, the electrode plate 15 is made of a plated steel plate obtained by plating the surface of the steel plate with nickel. As the steel sheet used as the base material of the plated steel sheet, for example, ordinary steel such as rolled steel or special steel such as stainless steel is used. The edge portion 15c of the electrode plate 15 has a rectangular frame shape, and is an uncoated region in which the positive electrode active material and the negative electrode active material are not coated. Examples of the positive electrode active material constituting the positive electrode 16 include nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode 17 include a hydrogen storage alloy. In the present embodiment, the formation region of the negative electrode 17 on the other surface 15b of the electrode plate 15 is slightly larger than the formation region of the positive electrode 16 on the one surface 15a of the electrode plate 15.

The separator 13 is formed in a sheet shape, for example. Examples of the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric made of polypropylene, methyl cellulose and the like, or a non-woven fabric. The separator 13 may be reinforced with a vinylidene fluoride resin compound.

The sealing body 12 is formed in a rectangular tubular shape as a whole by, for example, an insulating resin. The sealing body 12 is provided on the side surface 11a of the electrode laminated body 11 so as to surround the edge portion 15c of the electrode plate 15. The sealing body 12 holds the edge portion 15c on the side surface 11a. The sealing body 12 surrounds a plurality of first sealing portions (resin portions) 21 coupled to the edge portion 15c of the electrode plate 15 and the first sealing portion 21 along the side surface 11a from the outside, and first. It has 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, alkali-resistant insulating resins. Examples of the constituent materials of 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 continuously provided on one surface 15a of the electrode plate 15 over the entire circumference of the edge portion 15c, and has a rectangular frame shape when viewed from the stacking direction D. In the present embodiment, the first sealing portion 21 is provided not only on the electrode plate 15 of the bipolar electrode 14, but also on the electrode plate 15 of the negative electrode terminal 18 and the electrode plate 15 of the positive electrode 19. In the negative electrode terminal electrode 18, the first sealing portion 21 is provided on the edge portion 15c of the one surface 15a of the electrode plate 15, and in the positive electrode terminal electrode 19, both the edge portions 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 on the 15c.

The first sealing portion 21 is welded to one surface 15a of the electrode plate 15 by, for example, ultrasonic waves or thermocompression bonding, and is airtightly bonded. The first sealing portion 21 is, for example, a film having a predetermined thickness in the stacking direction D. The inside of the first sealing portion 21 is located between the edge portions 15c of the electrode plates 15 adjacent to each other in the stacking direction D. The outside of the first sealing portion 21 projects outward from 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 bonded to each other 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 a resin, and extends along the stacking direction D over the entire length of the electrode laminate 11. The second sealing portion 22 has a rectangular frame shape extending with the stacking direction D as the 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. More specifically, the second sealing portion 22, together with the first sealing portion 21, is between the bipolar electrodes 14 adjacent to each other along the stacking direction D, and the negative electrode termination electrodes 18 adjacent to each other along the stacking direction D. And the bipolar electrode 14, and between the positive electrode terminal 19 and the bipolar electrode 14 adjacent to each other along the stacking direction D are sealed. As a result, an airtightly partitioned internal space V is formed between the adjacent bipolar electrodes 14, between the negative electrode terminal 18 and the bipolar electrode 14, and between the positive electrode 19 and the bipolar electrode 14. ing. An aqueous electrolytic solution (not shown) containing an alkaline solution such as an aqueous potassium hydroxide solution is housed in the internal space V. The electrolytic solution is impregnated in the separator 13, the positive electrode 16, and the negative electrode 17.

Subsequently, 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, the region where the electrode plate 15 and the first sealing portion 21 overlap is a coupling region K between the electrode plate 15 and the first sealing portion 21. In the coupling region 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, but in the present embodiment, the entire surface of the electrode plate 15 (the entire surface including one surface 15a and the other surface 15b) is formed by electrolytic plating. It has been 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 protruding plating 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 base plating layer 32 and the protruding plating 33 is nickel. The base plating layer 32 is a layer for flattening the surface of the steel sheet 31, and is formed so as to cover the steel sheet 31.

The protruding plating 33 has, for example, a convex portion 33a formed on the base plating layer 32 as a base end, and has a tapered portion 33b on the tip end side of the convex 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 the roughening due to the plurality of protrusion-shaped plating 33, and the anchor effect is exhibited. As a result, the bond strength between the electrode plate 15 and the first sealing portion 21 can be improved. Further, since the protruding plating 33 has an undercut shape, the anchor effect can be improved.

The production of the electrode plate 15 includes a step of plating the steel plate 31. After the formation of the plating, a step of cleaning the plated steel sheet with an acid to remove oxides adhering to the surface of the plated steel sheet is performed. Further, after cleaning with acid, a step of cleaning the plated steel sheet with water to remove the acid from the surface of the plated steel sheet is performed. However, even when washed 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 on the plated steel sheet after cleaning and plating defects (parts where plating is not formed) 34 are present on 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 in which the rust 35 is generated comes into contact with the atmosphere, the rust 35 may proceed to the inside of the steel plate 31 and cause problems such as a decrease in the withstand voltage strength of the electrode plate 15 and leakage of the electrolytic solution.

On the other hand, in the power storage module 4, in the electrode laminate 11, the thickness of the base plating layer 32 of the electrode plate 15 located in the outermost layer is larger than the thickness of the base plating layer 32 of the electrode plate 15 located in the intermediate layer. It's getting bigger. There is a certain correlation between the plating thickness and the plating defects. When forming plating on a steel sheet, for example, if bubbles due to gas or the like adhere to the surface of the steel sheet, the formation of plating is insufficient around the bubbles, which causes plating defects in the steel sheet. As the plating thickness increases, 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 the plating thickness and the plating defect area. In the figure, the horizontal axis shows the plating thickness, and the vertical axis shows the plating defect area. The plating defect area is the ratio of the area of the plating defect to the area of plating. As shown in FIG. 5, as the plating thickness increases, the proportion of the plating defect area decreases. For example, when the plating thickness is 1.0 μm, the plating defect area is about 0.1%, and when the plating thickness is 2.0 μm, the plating defect area is reduced to about 0.01%. The ratio of the plating defect area is almost 0% in the range where the plating thickness is 4.0 μm or more.

In the power storage module 4, the thickness of the base plating layer 32 of the electrode plate 15 located on the outermost layer is larger than, for example, 2.0 μm. The thickness of the base plating layer 32 of the electrode plate 15 located on the outermost layer is preferably 4.0 μm or more, and more preferably 6.0 μm or more, from the viewpoint of suppressing the occurrence of plating defects. Further, the thickness of the base plating layer 32 of the electrode plate 15 located on 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 base 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 present embodiment, the electrode plate 15 forming the negative electrode terminal 18 and the electrode plate 15 forming the positive electrode 19 correspond to the metal plate located in the outermost layer, and the electrode plate 15 forming the bipolar electrode 14 is an intermediate layer. Corresponds to the metal plate located in. In the negative electrode terminal electrode 18, one surface 15a side of the electrode plate 15 is a surface that comes into contact with the atmosphere, and in the positive electrode terminal electrode 19, the other surface 15b side of the electrode plate 15 is a surface that comes into contact with the atmosphere. Therefore, in the negative electrode terminal electrode 18, it is preferable that at least the thickness of the base plating layer 32 on the one side 15a side of the electrode plate 15 satisfies the above range, and in the positive electrode terminal electrode 19, at least other than the electrode plate 15. It is preferable that the thickness of the base plating layer 32 on the direction 15b side satisfies the above range.

The thickness of the base plating layer 32 on the electrode plate 15 is represented by the thickness in the normal direction of the surface of the steel plate 31 between the protruding platings 33, as shown by reference numeral T in FIG. The thickness T of the base plating layer 32 can be measured by, for example, fluorescent X-rays.

As described above, in the power storage module 4, the thickness of the base plating layer 32 of the electrode plate 15 located at the outermost layer of the electrode laminate 11 is sufficiently secured. In the power storage module 4, the thickness of the base plating layer 32 is secured, so that the occurrence of the electrode plate 15 plating defect 34 of the outermost layer can be suppressed. Therefore, even if the electrode plate 15 comes into contact with the atmosphere, it is possible to suppress the generation and progress of rust 35, and it is possible to prevent the occurrence of problems such as a decrease in the pressure resistance strength of the electrode plate 15 and leakage of the electrolytic solution. On the other hand, in the power storage module 4, the thickness of the base plating layer 32 of the electrode plate 15 located in the intermediate layer is suppressed. Therefore, the amount of plating used in the electrode laminate 11 can be suppressed, and the manufacturing cost can be reduced.

In the present embodiment, the thickness of the base plating layer 32 of the electrode plate 15 located on the outermost layer is larger than 2.0 μm. By satisfying this range, the thickness of the base plating layer 32 can be sufficiently secured, and the occurrence of plating defects 34 in the electrode plate 15 of the outermost layer can be more reliably suppressed. Further, in the present embodiment, the thickness of the base plating layer 32 of the electrode plate 15 located on the outermost layer is 10 μm or less. By satisfying this range, it is possible to prevent the base plating layer 32 from becoming excessively thick. Therefore, the manufacturing cost of the power storage module 4 can be suppressed.

In the present embodiment, the thickness of the base plating layer 32 of the electrode plate 15 located in the intermediate layer is 2.0 μm or less. By reducing the thickness of the base plating layer 32 of the electrode plate 15 located in the intermediate layer, it is possible to sufficiently reduce the amount of plating used in the electrode laminate 11, further reducing the manufacturing cost of the power storage module 4. Is planned.

In the present embodiment, the electrode laminate 11 has a negative electrode termination electrode 18 on one end side in the stacking direction D and a positive electrode termination electrode 19 on the other end side in the stacking direction D. The electrode plate 15 located in the outermost layer is an electrode plate 15 that constitutes the negative electrode terminal electrode 18 and an electrode plate 15 that constitutes the positive electrode terminal electrode 19. As a result, it is possible to prevent the occurrence of plating defects 34 in the electrode plate 15 of the negative electrode terminal 18 and the positive electrode 19 which are the outermost layers.

The present disclosure is not limited to the above embodiment. For example, in the above embodiment, the electrode plate 15 constituting the negative electrode terminal electrode 18 and the electrode plate 15 constituting the positive electrode terminal 19 correspond to the electrode plate (metal plate) 15 located in the outermost layer, but the outermost layer. The configuration is not limited to this. For example, an uncoated electrode may be further laminated on the outside of the stacking direction D with respect to at least one of the negative electrode terminal electrode 18 and the positive electrode 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 an adjacent terminal electrode.

In this case, the thickness of the base plating layer 32 of the uncoated electrode located in the outermost layer may be larger than the thickness of the base plating layer 32 of the electrode plate 15 located in the intermediate layer. The thickness of the base plating layer 32 of the electrode plate 15 of the negative electrode terminal 18 or the positive electrode 19 located inside the stacking direction D with respect to the uncoated electrode is equivalent to the thickness of the base plating layer 32 of the uncoated electrode. It may be the same as the thickness of the base 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 ... Energy storage module, 11 ... Electrode laminate, 12 ... Sealed body, 14 ... Bipolar electrode, 15 ... Electrode plate (metal plate), 18 ... Negative electrode terminal electrode, 19 ... Positive electrode terminal electrode, 31 ... Steel plate, 32 ... Base Plating layer, 33 ... protruding plating, D ... stacking direction, V ... internal space.

Claims (5)

An electrode laminate formed by laminating metal plates constituting an electrode including a plurality of bipolar electrodes, and
In the electrode laminate, an internal space is formed between the electrodes adjacent to each other in the stacking direction, and a sealing body for sealing the internal space is provided.
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.
A power storage module in which the thickness of the base plating layer of the metal plate located in the outermost layer of the electrode laminate is larger than the thickness of the base plating layer of the metal plate located in the intermediate layer. The power storage module according to claim 1, wherein the thickness of the base plating layer of the metal plate located on the outermost layer is larger than 2.0 μm. The power storage module according to claim 1 or 2, wherein the thickness of the base plating layer of the metal plate located on the outermost layer is 10 μm or less. The power storage module according to any one of claims 1 to 3, wherein the thickness of the base plating layer of the metal plate located in the intermediate layer is 2.0 μm or less. The electrode laminate has a negative electrode terminal electrode on one end side in the stacking direction and a positive electrode terminal electrode on the other end side in the stacking direction.
The power storage module according to any one of claims 1 to 4, wherein the metal plate located in the outermost layer is a metal plate constituting the negative electrode terminal electrode and a metal plate constituting the positive electrode terminal electrode.

Images