JP7116631B2 - storage module - Google Patents

Description

The present invention relates to an electric storage module.

As a conventional power storage module, a bipolar battery is known which includes a bipolar electrode in which a positive electrode is formed on one side of an electrode plate and a negative electrode is formed on the other side (see Patent Document 1). A bipolar battery includes 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

By the way, in the electric storage module as described above, a negative terminal electrode having a negative electrode formed inside the electrode laminate is arranged at one end in the stacking direction of the electrode laminate. The electrode plate of the negative terminal electrode is also sealed with a sealing body. However, if the electrolyte contains an alkaline solution, the so-called alkali creep phenomenon causes the electrolyte to flow along the surface of the electrode plate of the negative terminal electrode. , it may leak out of the power storage module through between the sealing body and the electrode plate. If the electrolyte leaks out of the battery module and diffuses, it may cause corrosion of the conductive plate placed in contact with the battery module, short circuit between the battery module and the restraining member, etc., which may reduce reliability. can be.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an electricity storage module capable of suppressing leakage of an electrolytic solution to the outside of the electricity storage module due to an alkali creep phenomenon.

An electricity storage module according to one aspect of the present invention includes an electrode laminate including a laminate of a plurality of bipolar electrodes; A sealing body provided so as to surround the side surface of the body, forming an internal space between adjacent electrodes and sealing the internal space, and an electrolytic solution containing an alkaline solution contained in the internal space, The sealing body includes a resin portion arranged between adjacent electrodes, and a low moisture permeability member coupled to one end of the electrode laminate in the stacking direction and having lower moisture permeability than the resin portion.

The sealing body of this power storage module includes a resin portion arranged between adjacent electrodes, and a low moisture permeability member coupled to one end of the electrode laminate in the stacking direction and having moisture permeability lower than that of the resin portion. By providing the low-moisture-permeability member in this manner, moisture contained in the air, which is a factor that accelerates the alkali creep phenomenon, is absorbed into the power storage module at the one end side of the electrode laminate where the alkali creep phenomenon may occur. You can prevent it from entering. Therefore, the electrolyte is prevented from seeping into the excess space from between the electrode plate of the negative terminal electrode and the resin portion, so that the electrolyte can be prevented from leaking out of the power storage module due to the alkaline creep phenomenon.

The low-moisture-permeability member may have a multilayer structure laminated in the lamination direction, and may include a bonding layer bonded to the sealing body and an alkali-resistant layer bonded to one end of the electrode laminate. According to this configuration, the bonding layer can improve the bonding strength between the low-moisture-permeable member and the sealing body. Further, the alkali-resistant layer can suppress deterioration of the low-moisture-permeable member due to the electrolytic solution even when an alkali creep phenomenon occurs.

The electrode laminate has a metal plate arranged outside in the stacking direction with respect to the electrode plate of the negative terminal electrode, and has an extra space surrounded by the low moisture-permeable member, the resin portion, and the metal plate. good too. According to this configuration, since the closed surplus space is formed on the one end side of the negative terminal electrode, moisture contained in the outside air enters between the sealing body and the electrode plate of the negative terminal electrode. can be suppressed. In addition, the low moisture permeability member can prevent moisture contained in the outside air from entering the surplus space. Therefore, it is possible to more reliably prevent the electrolyte from seeping out of the power storage module due to the alkali creep phenomenon.

One end of the electrode laminate may be roughened in the bonding region between the low-moisture-permeability member and the electrode laminate. According to this configuration, it is possible to improve the bonding strength between the low-moisture-permeable member and the one end of the electrode laminate due to the anchor effect.

ADVANTAGE OF THE INVENTION According to this invention, the electrical storage module which can suppress that electrolyte solution seeps out of an electrical storage module by an alkaline creep phenomenon is provided.

1 is a schematic cross-sectional view showing a power storage device according to one embodiment; FIG. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module shown in FIG. 1; FIG. 3 is an enlarged cross-sectional view showing a part of the power storage module of FIG. 2; FIG. 4 is a schematic cross-sectional view showing the structure of a low moisture-permeable member; FIG. 10 is a partially enlarged cross-sectional view of a power storage module according to a comparative example;

Various embodiments are described in detail below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and overlapping descriptions are omitted.

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 of the module stack 2 .

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

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

Inside the conductive plate 5, a plurality of flow paths 5a for circulating a coolant such as air are provided. The flow path 5a extends along a direction that intersects (perpendicularly) the stacking direction and the lead-out direction of the positive electrode terminal 6 and the negative electrode terminal 7, for example. The conductive plate 5 functions as a connecting member that electrically connects the power storage modules 4 to each other, and also functions as a radiator plate that dissipates the heat generated in the power storage modules 4 by circulating the coolant in these flow paths 5a. have a combination of functions. In the example of FIG. 1, the area of the conductive plate 5 when viewed from the stacking direction 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 less than the area of the power storage module. 4 , or may be larger than the area of power storage module 4 .

The restraining member 3 is composed of a pair of end plates 8 that sandwich the module stack 2 in the stacking direction, and fastening bolts 9 and nuts 10 that fasten the end plates 8 together. The end plate 8 is a rectangular metal plate having an area one size larger than the area of the storage module 4 and the conductive plate 5 when viewed in the stacking direction. 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 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, and the tip portion of the fastening bolt 9 protruding from the insertion hole 8a of the other end plate 8 has a , a nut 10 is screwed. As a result, the storage module 4 and the conductive plate 5 are sandwiched between the end plates 8 to form a module laminate 2 as a unit, and a binding load is applied to the module laminate 2 in the stacking direction.

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. 3 is an enlarged cross-sectional view showing a part of the power storage module of FIG. 2. FIG. As shown in FIGS. 2 and 3 , 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 has an electrode 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. ing. 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. In addition, it is preferable that the separator 13 extends in a direction intersecting the stacking direction D so as to contact a first sealing portion 21 which will be described later. Thereby, the short circuit between electrodes can be suppressed.

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 15a of the electrode plate 15 of the negative terminal electrode 18 constitutes one outer surface in the stacking direction D of the electrode laminate 11, and is electrically connected to one conductive plate 5 (see FIG. 1) adjacent to the electricity 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 of the electrode laminate 11, and is electrically connected to the other conductive plate 5 (see FIG. 1) adjacent to the electricity storage module 4. It is connected.

The electrode plate 15 is made of metal such as nickel or nickel-plated steel plate, for example. As an example, the electrode plate 15 is a rectangular metal foil made of nickel. 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, for example, on a sheet. Examples of the separator 13 include porous films made of polyolefin resins such as polyethylene (PE) and polypropylene (PP), and woven or nonwoven fabrics made of polypropylene, polypropylene, methyl cellulose, and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound. Note that the separator 13 is not limited to a sheet shape, and may be bag-shaped.

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 member 12 includes a plurality of first sealing portions 21 (resin portions) 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. It includes a second sealing portion 22 (sealing portion) coupled to each of the sealing portions 21 and a low moisture permeability member 23 coupled to one end of the electrode stack 11 in the stacking direction D. A detailed configuration of the low moisture permeability member 23 will be described later.

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 annular shape when viewed from the stacking direction D. As shown in FIG. The first sealing portion 21 is welded to the one surface 15a of the electrode plate 15 by, for example, ultrasonic waves or heat, 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.

A region where the edge portion 15 c and the first sealing portion 21 overlap on the one surface 15 a of the electrode plate 15 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. The roughened region may be only the coupling region K, but in this embodiment, the entire one surface 15a of the electrode plate 15 is roughened. Roughening can be achieved by forming a plurality of protrusions by, for example, electroplating. Since a plurality of projections can be formed on the one surface 15a, at the joint interface with the first sealing portion 21 on the one surface 15a, the molten resin enters between the plurality of projections formed by surface roughening, and anchors. Effective. Thereby, the bonding strength between the electrode plate 15 and the first sealing portion 21 can be improved. The projections formed during surface roughening have, for example, a shape that tapers from the proximal side to the distal side. As a result, the cross-sectional shape between adjacent projections becomes an undercut shape, making it possible to enhance the anchor effect.

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 tubular shape (annular shape) extending with 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 terminal electrodes 14 adjacent to each other along the stacking direction D. 18 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 an 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 .

The electrode laminate 11 further has a metal plate 20 . The metal plate 20 is arranged outside in the stacking direction D with respect to the electrode plate 15 of the negative terminal electrode 18 . The metal plate 20 has the other surface 20b facing the one surface 15a of the electrode plate 15 of the negative terminal electrode 18, and the one surface 20a on the opposite side of the other surface 20b. The one surface 20a and the other surface 20b of the metal plate 20 are not coated with the positive electrode active material and the negative electrode active material, and the entire surfaces of the one surface 20a and the other surface 20b are uncoated regions. That is, in this embodiment, the metal plate 20 is an uncoated electrode plate on which neither the positive electrode 16 nor the negative electrode 17 is provided. Further, the metal plate 20 has a rectangular contact portion C that is recessed toward the negative terminal electrode 18 and contacts the electrode plate 15 of the negative terminal electrode 18 . More specifically, at the contact portion C, the other surface 20b of the metal plate 20 contacts the one surface 15a of the electrode plate 15 of the negative terminal electrode 18, and the one surface 20a of the metal plate 20 contacts the conductive plate 5 (see FIG. 1). ). Thereby, the negative terminal electrode 18 is electrically connected to the conductive plate 5 via the metal plate 20 . Like the electrode plate 15, the metal plate 20 is made of metal such as nickel or nickel-plated steel plate.

Regions of the one surface 20 a and the other surface 20 b of the metal plate 20 where the edge portion 20 c and the first sealing portion 21 overlap are roughened in the same manner as the surface of the electrode plate 15 . The roughened region may be only the region where the edge portion 20c and the first sealing portion 21 are joined, but in the present embodiment, the entire one surface 20a and the other surface 20b of the metal plate 20 are roughened. there is A low-moisture-permeable member 23 is coupled to an edge portion 20c on one surface 20a of the metal plate 20, and a first sealing portion 21 is coupled to an edge portion 20c on the other surface 20b of the metal plate 20. . Thus, the first sealing portion 21, the electrode plate 15 of the negative terminal electrode 18, and the metal plate 20 form a surplus space VA in which no electrolytic solution is contained. The surplus space VA is formed so as to surround the contact portion C when viewed from the stacking direction D. As shown in FIG. When viewed from a cross section along the stacking direction D, the surplus space VA has a substantially triangular shape in which the height (dimension along the stacking direction D) decreases from the first sealing portion 21 side toward the contact portion C side. ing. In addition, the power storage module 4 has a surplus space VB that does not contain an electrolytic solution and is surrounded by the low-moisture-permeable member 23, the first sealing portion 21, the metal plate 20, and the second sealing portion 22. there is Surplus space VB is formed so as to surround the outside of edge 20c of metal plate 20 . When viewed from a cross section along the stacking direction D, the surplus space VB has a substantially rectangular shape.

Next, the configuration of the low-moisture-permeable member 23 will be described in detail with reference to FIGS. 3 and 4. FIG. As shown in FIG. 3 , in the power storage module 4 according to this embodiment, the metal plate 20 is arranged at one end of the electrode laminate 11 , and the low moisture permeability member 23 is coupled to the metal plate 20 . Like the first sealing portion 21, the low moisture permeability member 23 has a rectangular annular shape when viewed from the stacking direction D, and is provided continuously over the entire circumference of the edge 20c on the one surface 20a of the metal plate 20. ing. The low-moisture-permeable member 23 is welded to one surface 20a of the metal plate 20 by, for example, ultrasonic waves or heat, and is airtightly joined. The low moisture permeability member 23 is a film having a predetermined thickness in the lamination direction D, for example. In this embodiment, the thickness of the low moisture-permeable member 23 is thinner than the thickness of the first sealing portion 21 . As an example, the thickness of the low moisture-permeable member 23 can be 50 μm or more and 200 μm or less. The thickness of the low moisture-permeable member 23 may be equal to the thickness of the first sealing portion 21 or may be thicker than the thickness of the first sealing portion 21 .

The low moisture permeability member 23 has moisture permeability lower than that of the first sealing portion 21 . As shown in FIG. 4, the low-moisture-permeable member 23 has a multi-layer structure laminated along the lamination direction D. As shown in FIG. In this embodiment, the low-moisture-permeable member 23 has a bonding layer 23A, an alkali-resistant layer 23B, and a barrier layer 23C. The bonding layer 23A constitutes one surface of the low-moisture-permeable member 23 on one end side in the stacking direction D, and is a layer bonded to the second sealing portion 22 . The alkali-resistant layer 23B constitutes one surface of the low-moisture-permeable member 23 on the other end side in the stacking direction D, and is a layer that is bonded to the one surface 20a of the metal plate 20 . The barrier layer 23C is a layer positioned between the bonding layer 23A and the alkali resistant layer 23B. The binding layer 23A is made of, for example, a polyolefin resin such as polypropylene (PP) or polyethylene (PE), or a material compatible with the second sealing portion 22 . The alkali-resistant layer 23B is made of, for example, a polyolefin resin such as polypropylene (PP) or polyethylene (PE), or a material having alkali resistance. The barrier layer 23C is made of, for example, a metal such as nickel or aluminum, or a material having low gas permeability and moisture permeability such as ethylene-vinyl alcohol copolymer resin (EVOH).

Further, in this embodiment, the thickness of the barrier layer 23C is greater than the thickness of the bonding layer 23A and the thickness of the alkali-resistant layer 23B. The thickness of the bonding layer 23A and the thickness of the alkali-resistant layer 23B are substantially the same. By relatively increasing the thickness of the barrier layer 23C in this manner, the moisture permeability of the low moisture permeability member 23 can be further reduced. As an example, the thickness of the bonding layer 23A can be 10 μm or more and 50 μm or less, the thickness of the alkali resistant layer 23B can be 10 μm or more and 50 μm or less, and the thickness of the barrier layer 23C can be 10 μm or more and 150 μm or less. Also, the thickness of the barrier layer 23C may be two to five times the thickness of the bonding layer 23A and the alkali-resistant layer 23B. The relationship between the thicknesses of the layers of the low-moisture-permeability member 23 is not particularly limited. For example, the thickness of the barrier layer 23C may be thinner than the thickness of the bonding layer 23A and the thickness of the alkali-resistant layer 23B. In this case, it is possible to obtain an effect that a sufficient amount of bonding layer with the metal plate can be secured. Furthermore, the thickness of the bonding layer 23A and the thickness of the alkali resistant layer 23B may not be the same.

Next, the effects of the power storage module 4 will be described with reference to FIG. 5 . FIG. 5 is an enlarged cross-sectional view of a main part of a power storage module according to a comparative example. As shown in FIG. 5 , in the power storage module 100 according to the comparative example, the first sealing portion 21 instead of the low moisture permeability member 23 is coupled to one end of the electrode stack 11 in the stacking direction D, and The metal plate 20 is not arranged at one end of the electrode stack 11 in the stacking direction D, and the negative terminal electrode 18 is located at one end of the electrode stack 11, which is different from the power storage module 4 according to the present embodiment. is doing.

In the storage module 100, due to the so-called alkali creep phenomenon, the electrolytic solution present in the internal space V runs along the surface of the electrode plate 15 of the negative electrode terminal electrode 18, and flows between the electrode plate 15 and the first sealing portion 121A in the joint region K. may seep out to the one surface 15a side of the electrode plate 15 through the gap between the electrodes. In FIG. 4, an arrow A indicates the movement path of the electrolyte L in the alkali creep phenomenon. Due to electrochemical factors, fluid phenomena, and the like, this alkali creep phenomenon can occur during charging and discharging of the power storage device and during no load. The alkali creep phenomenon occurs due to the presence of channels for the negative electrode potential, moisture, and electrolyte L, and progresses over time.

On the other hand, the sealing body 12 of the electricity storage module 4 according to the present embodiment is coupled to the first sealing portion 21 arranged between the adjacent electrodes and one end of the electrode stack 11 in the stacking direction D. and a low moisture permeability member 23 having moisture permeability lower than that of the 1 sealing portion 21 . By providing the low-moisture-permeability member 23 in this manner, moisture contained in the air, which is a factor that accelerates the alkali creep phenomenon, can be prevented from occurring in the power storage module at the one end side of the electrode laminate 11 where the alkali creep phenomenon can occur. 4 can be suppressed. Therefore, the electrolyte is prevented from seeping into the surplus spaces VA and VB from between the electrode plate 15 of the negative terminal electrode 18 and the first sealing portion 21, so that the electrolyte leaks into the power storage module 4 due to the alkaline creep phenomenon. exudation to the outside can be suppressed.

In addition, the low moisture permeability member 23 has a multilayer structure laminated in the lamination direction D, has compatibility with the sealing body 12 (second sealing portion 22), and is bonded to the sealing body 12. and an alkali-resistant layer 23B that is bonded to one end of the electrode laminate 11 (the metal plate 20 in this embodiment). As a result, it is possible to improve the bonding strength between the low-moisture-permeable member and the sealing body by means of the bonding layer 23A. Further, the alkali-resistant layer 23B can suppress deterioration of the low-moisture-permeable member due to the electrolytic solution even when an alkali creep phenomenon occurs.

Further, the electrode laminate 11 has a metal plate 20 arranged outside in the lamination direction D with respect to the electrode plate 15 of the negative terminal electrode 18, and has a low moisture-permeable member 23, a first sealing portion 21, and a second It has a surplus space VB surrounded by the sealing portion 22 and the metal plate 20 . As a result, a closed surplus space VB is formed on the one end side of the negative electrode terminating electrode 18, so that moisture contained in the outside air is trapped between the sealing body 12 and the electrode plate 15 of the negative electrode terminating electrode 18. Intrusion can be suppressed. In addition, the low moisture permeability member 23 can prevent moisture contained in the outside air from entering the surplus space VB. Therefore, it is possible to more reliably suppress the leakage of the electrolytic solution to the outside of the power storage module 4 due to the alkali creep phenomenon.

In addition, in the bonding region between the low-moisture-permeable member 23 and the electrode laminate 11, one end of the electrode laminate 11 (that is, one surface 20a of the metal plate 20) is roughened. Thereby, the bonding strength between the low-moisture-permeable member 23 and one end of the electrode laminate 11 can be improved by the anchor effect.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made. For example, in the above embodiment, the electrode laminate 11 has the metal plate 20 outside the negative terminal electrode 18 , but the electrode laminate 11 may not have the metal plate 20 . In this case, the electrode plate 15 of the negative terminal electrode 18 corresponds to one end of the electrode stack 11 , and the low moisture-permeable member 23 is coupled to one surface 15 a of the electrode plate 15 of the negative terminal electrode 18 . In this case as well, the low moisture permeability member 23 prevents moisture contained in the outside air from entering the power storage module 4 , so that the electrolyte seeps out of the power storage module 4 due to the alkaline creep phenomenon. can be suppressed.

Note that when the electrode laminate 11 does not have the metal plate 20 , the power storage module 4 has an extra space surrounded by the low moisture-permeable member 23 , the first sealing portion 21 , the second sealing portion 22 , and the metal plate 20 . VB and the surplus space VA surrounded by the first sealing portion 21 , the metal plate 20 and the negative terminal electrode 18 may not be provided.

Further, in the above embodiment, an example in which the low-moisture-permeability member 23 has a three-layer structure consisting of the bonding layer 23A, the alkali-resistant layer 23B, and the barrier layer 23C has been described, but the low-moisture-permeability member 23 has more layers. may have Alternatively, the low moisture permeability member 23 may have a single layer structure consisting only of the barrier layer 23C without the bonding layer 23A and the alkali-resistant layer 23B.

Also, the rectangular frame-shaped first sealing portion 21 may be coupled to the other surface 15 b side of the electrode plate 15 of the positive terminal electrode 19 . This first sealing portion 21 can also be coupled with another first sealing portion 21 by a second sealing portion 22 . Also, the edge of the first sealing portion 21 coupled to the other surface 15b side of the electrode plate 15 of the positive terminal electrode 19 and the first sealing portion 21 of the one surface 15a side of the electrode plate 15 of the positive terminal electrode 19 may be joined by hot plate welding or the like.

4 power storage module 11 electrode laminate 11a side surface 12 sealing body 13 separator 14 bipolar electrode 15 electrode plate 18 negative terminal electrode 20 metal plate 21 first Sealing portion (resin portion) 22 Second sealing portion 23 Low moisture permeability member 23A Binding layer 23B Alkali-resistant layer 23C Barrier layer D Lamination direction V Internal space VA , VB . . . surplus space.

Claims (3)

an electrode laminate including a laminate of a plurality of bipolar electrodes and a negative terminal electrode disposed on one end side of the laminate in the stacking direction;
a sealing body provided so as to surround the side surface of the electrode stack, forming an internal space between adjacent electrodes and sealing the internal space;
an electrolytic solution containing an alkaline solution housed in the internal space,
The encapsulant is
a resin portion disposed between the adjacent electrodes;
a low moisture permeability member having moisture permeability lower than that of the resin portion coupled to the one end of the electrode laminate in the stacking direction ,
The low moisture-permeable member has a multilayer structure laminated in the lamination direction,
A power storage module , comprising: a bonding layer bonded to the encapsulant; and an alkali-resistant layer bonded to the one end of the electrode laminate . The electrode laminate has a metal plate disposed outside in the stacking direction with respect to the electrode plate of the negative terminal electrode, and a surplus metal plate surrounded by the low moisture-permeable member, the resin portion, and the metal plate. The power storage module according to claim 1 , having a space. 3. The electricity storage module according to claim 1, wherein said one end of said electrode laminate is roughened in a bonding region between said low moisture-permeable member and said electrode laminate.

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