JP2019185945A - Power storage module - Google Patents

Abstract

To provide a power storage module in which reliability is improved.SOLUTION: A power storage module 4 includes an electrode laminate 11 having multiple electrodes laminated via a separator 13, and a sealed body 12 provided on a lateral face 11a of the electrode laminate 11, and sealing the electrodes adjoining in a lamination direction D. In an internal space V formed between the electrodes adjoining in the lamination direction D, electrolyte L composed of alkaline solution is received. The electrodes include multiple bipolar electrodes 14, and a negative pole end electrode 18. The negative pole end electrode 18 includes an electrode plate 15 having an inside 15d on which a negative electrode 17 is formed, and is placed at one end of the electrode laminate 11 in the lamination direction D. On the surface of a marginal part 15c of the electrode plate 15 of the negative pole end electrode 18, a water repellent material 31 is provided.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power storage module.

  As a conventional power storage module, a bipolar battery including a bipolar electrode in which a positive electrode is formed on one surface of an electrode plate and a negative electrode is formed on the other surface is known (see Patent Document 1). The bipolar battery is provided with a laminate formed by laminating a plurality of bipolar electrodes via a separator. A sealing body that seals between bipolar electrodes adjacent to each other in the stacking direction is provided on a side surface of the stacked body, and an electrolytic solution is accommodated in an internal space formed between the bipolar electrodes.

JP 2011-204386 A

  In the power storage module as described above, a negative electrode termination electrode composed of an electrode plate having a negative electrode formed on the inner surface is disposed at one end in the stacking direction of the stacked body. The edge of the electrode plate of the negative electrode termination electrode is also sealed with a sealing body. However, when the electrolyte solution is made of an alkaline solution, the electrolyte solution covers the surface of the electrode plate of the negative electrode termination electrode due to a so-called alkali creep phenomenon. It may be transmitted to the outer surface side of the electrode plate through the sealing body and the electrode plate. If the electrolyte leaks to the outer surface side and diffuses, for example, corrosion of the conductive plate disposed adjacent to the negative electrode termination electrode or a short circuit between the negative electrode termination electrode and the restraining member may occur. It is not preferable.

  Therefore, an object of the present invention is to provide a power storage module with improved reliability.

  An electricity storage module according to one aspect of the present invention includes a laminated body including a plurality of electrodes laminated via separators, and a seal provided between the electrodes adjacent to each other in the lamination direction of the laminated body. An internal space formed between electrodes adjacent to each other in the stacking direction contains an electrolyte solution made of an alkaline solution, and the electrode includes a plurality of bipolar electrodes and a negative electrode termination electrode, The bipolar electrode includes an electrode plate, a positive electrode provided on the first surface of the electrode plate, and a negative electrode provided on the second surface opposite to the first surface of the electrode plate. The electrode plate on which the negative electrode is formed is disposed at one end of the laminate in the stacking direction, and a water repellent material is provided on the surface of the edge of the electrode plate of the negative electrode termination electrode.

  In this power storage module, a water repellent material is provided on the surface of the edge of the electrode plate of the negative electrode termination electrode (that is, the region included in the electrolyte movement path due to the alkali creep phenomenon). Thereby, the leakage of the electrolyte solution due to the alkali creep phenomenon from the internal space between the electrode plate of the negative electrode termination electrode and the electrode plate adjacent to the electrode plate is suppressed. As a result, occurrence of secondary damage such as a short circuit due to the leaked electrolyte can be suppressed, and reliability can be improved.

  The water repellent material may have a first portion provided at the end of the electrode plate of the negative electrode termination electrode. In this case, the first portion can prevent the electrolyte from creeping up due to the alkali creep phenomenon at the end of the electrode plate of the negative electrode termination electrode. Thereby, the leakage of the electrolyte solution due to the alkali creep phenomenon can be accurately suppressed.

  The water repellent material may have a second portion provided on the inner surface of the electrode plate of the negative electrode termination electrode continuously with the first portion. In this case, by further providing the second portion in addition to the first portion, it is possible to further suppress the electrolyte creeping up due to the alkali creep phenomenon at the inner surface and the end portion of the electrode plate of the negative electrode termination electrode. .

  The sealing body has a bonded portion bonded to the outer edge of the electrode plate of the negative electrode termination electrode, and the water repellent material is continuous with the inner end portion of the bonded portion when viewed from the stacking direction. As such, it may have a third portion provided on the outer surface. In this case, the third portion can suppress leakage of the electrolytic solution to the outside due to the alkali creep phenomenon. Furthermore, according to the 3rd part, the penetration | invasion of the water | moisture content from the exterior to internal space can also be suppressed. As a result, the generation of an alkali concentration gradient in the vicinity of the bonded portion between the bonded portion and the electrode plate of the negative electrode termination electrode is suppressed. As a result, the driving force of alkali creep can be suppressed, and the leakage of the electrolytic solution can be further suppressed. be able to.

  Of the surface of the negative electrode termination electrode, at least a portion where the water repellent material is provided may be a rough surface provided with a plurality of fine protrusions. In this case, based on the Cassie-Baxter theory or the like, the water repellent effect (water repellency) of the water repellent material can be improved as compared with the case where the water repellent material is provided on a flat surface. Thereby, the creeping of the electrolyte solution due to the alkali creep phenomenon can be further effectively suppressed.

  Of the surface of the negative electrode termination electrode, at least a portion where the water repellent material is provided may be a flat surface. In this case, the water repellent material can be formed in a uniform and stable film shape by providing the water repellent material on a flat surface (that is, a surface with very little unevenness). This makes it difficult for pinholes or the like to occur in the water repellent material. As a result, it is possible to stably suppress the electrolyte creeping up due to the alkali creep phenomenon.

  The water repellent material may be formed of a fluorine resin material. In this case, by forming the water repellent material with a fluororesin material excellent in both water repellency and alkali resistance, it is possible to more effectively suppress the leakage of the electrolyte due to the alkali creep phenomenon.

  According to one embodiment of the present invention, a power storage module with improved reliability can be provided.

It is a schematic sectional drawing which shows the electrical storage apparatus containing the electrical storage module of one Embodiment. It is a schematic sectional drawing which shows the internal structure of the electrical storage module of FIG. It is a schematic sectional drawing which shows the joining interface of an electrode plate and the 1st sealing part of a sealing body. It is a schematic sectional drawing which expands and shows a part of FIG.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and duplicate descriptions are omitted.

  FIG. 1 is a schematic cross-sectional view showing a power storage device including the power storage module of the present embodiment. 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 power storage module stack 2 formed by stacking a plurality of power storage modules 4 and a restraining member 3 that applies a restraining load to the power storage module stack 2 in the stacking direction.

  The power storage module laminate 2 includes a plurality (three in the present embodiment) of power storage modules 4 and a plurality of conductive plates 5 arranged between the power storage modules 4 and 4. The power storage module 4 is, for example, a bipolar battery including a bipolar electrode 14 described later, 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 metal hydride 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 illustrated.

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

  Inside each conductive plate 5, a plurality of flow paths 5a for circulating a refrigerant such as air are provided. Each flow path 5a extends in parallel to each other in a direction orthogonal to, for example, the stacking direction and the drawing direction of the positive electrode terminal 6 and the negative electrode terminal 7. By causing the refrigerant to flow through these flow paths 5a, the conductive plate 5 functions as a connecting member that electrically connects the power storage modules 4 and 4 and also dissipates heat generated in the power storage module 4. It also has the function as In the example of FIG. 1, the area of the conductive plate 5 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 the area of the power storage module 4. It may be the same as or larger than the area of the power storage module 4.

  The restraining member 3 includes a pair of end plates 8 and 8 that sandwich the power storage module stack 2 in the stacking direction, and a fastening bolt 9 and a nut 10 that fasten the end plates 8 and 8 together. The end plate 8 is a rectangular metal plate having an area that is slightly larger than the areas of the power storage module 4 and the conductive plate 5 as viewed from the stacking direction. On the inner side surface of the end plate 8 (the surface on the power storage module laminate 2 side), an electrically insulating film F is provided. The film F insulates the end plate 8 from the conductive plate 5.

  An insertion hole 8 a is provided at the edge of the end plate 8 at a position that is outside the power storage module stack 2. The fastening bolt 9 is passed from the insertion hole 8 a of one end plate 8 toward the insertion hole 8 a of the other end plate 8, and at the tip of the fastening bolt 9 protruding from the insertion hole 8 a of the other end plate 8. The nut 10 is screwed together. As a result, the power storage module 4 and the conductive plate 5 are sandwiched between the end plates 8 and 8 and unitized as the power storage module stack 2, and a restraining load is applied to the power storage module stack 2 in the stacking direction.

  Next, the configuration of the power storage module 4 will be described in more detail. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module 4. As shown in the figure, the power storage module 4 includes an electrode laminate 11 (laminate) and a sealing body 12 that seals the electrode laminate 11.

  The electrode laminate 11 is configured by laminating a plurality of electrodes (a plurality of bipolar electrodes 14, a negative electrode termination electrode 18, and a positive electrode termination electrode 19) via a separator 13. In this example, the stacking direction D of the electrode stack 11 coincides with the stacking direction of the power storage module stack 2. The bipolar electrode 14 is an electrode made of an electrode plate 15 having a positive electrode 16 formed on the first surface 15a and a negative electrode 17 formed on the second surface 15b opposite to the first surface 15a. In the electrode stack 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of one bipolar electrode 14 adjacent in the stacking direction D across the separator 13. In the electrode stack 11, the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of the other bipolar electrode 14 adjacent in the stacking direction D with the separator 13 interposed therebetween.

  In the electrode stack 11, a negative electrode termination electrode 18 is disposed at one end in the stacking direction D, and a positive electrode termination electrode 19 is disposed at the other end in the stacking direction D. The negative electrode termination electrode 18 includes an electrode plate 15 having a negative electrode 17 formed on an inner surface (a surface on the center side in the stacking direction D) 15d. The positive electrode termination electrode 19 includes an electrode plate 15 having a positive electrode 16 formed on an inner surface (a surface on the center side in the stacking direction D) 15f. The negative electrode 17 of the negative electrode termination electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D through the separator 13. The positive electrode 16 of the positive electrode termination electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D through the separator 13. One conductive plate 5 adjacent to the power storage module 4 is in contact with the outer surface 15 e of the electrode plate 15 of the negative electrode termination electrode 18. The other conductive plate 5 adjacent to the power storage module 4 is in contact with the outer surface 15 g of the electrode plate 15 of the positive electrode termination electrode 19.

  The electrode plate 15 is a rectangular metal foil made of nickel, for example. Alternatively, the electrode plate 15 may be a nickel-plated steel plate. An edge portion (edge portion of the bipolar electrode 14) 15c of the electrode plate 15 is an uncoated region where the positive electrode active material and the negative electrode active material are not applied. An example of the positive electrode active material constituting the positive electrode 16 is nickel hydroxide. As a negative electrode active material which comprises the negative electrode 17, a hydrogen storage alloy is mentioned, for example. In the present embodiment, the formation region of the negative electrode 17 on the second surface 15 b of the electrode plate 15 is slightly larger than the formation region of the positive electrode 16 on the first 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 a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose, and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound. The separator 13 is not limited to a sheet shape, and may be a bag shape.

  The sealing body 12 is formed in a rectangular cylindrical shape with an insulating resin, for example. Examples of the resin material constituting the sealing body 12 include polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE). The sealing body 12 is configured to surround a side surface 11 a of the electrode stack 11 formed by stacking the bipolar electrodes 14.

  The sealing body 12 was provided so as to surround the first sealing portion 21 provided along the edge portion 15c of the electrode plate 15 of each bipolar electrode 14 and the entire first sealing portion 21 from the outside. The second sealing portion 22 is configured. The first sealing portion 21 is continuously provided over all sides of the electrode plate 15 at the edge portion 15 c (uncoated region) on the first surface 15 a side of the electrode plate 15. The first sealing portion 21 is coupled to the edge portion 15c by welding. A part of the inner side of the first sealing portion 21 is located between the edge portions 15c of the electrode plates 15 of the bipolar electrodes 14 and 14 adjacent in the stacking direction D, and a part of the outer side is the electrode plate 15. Overhangs from the outside. The first sealing portion 21 is buried in the second sealing portion 22 at a part of the outside.

  The second sealing portion 22 is formed by resin injection molding, for example, and extends over the entire length in the stacking direction D of the electrode stack 11. The second sealing portion 22 is welded to the outer surface of the first sealing portion 21 by, for example, heat during injection molding, and seals between the bipolar electrodes 14 and 14 adjacent in the stacking direction D. Thereby, an internal space V is formed between the bipolar electrodes 14 adjacent to each other in the stacking direction D. In the internal space V, an electrolytic solution (not shown) made of an alkaline solution such as an aqueous potassium hydroxide solution is accommodated. The electrolytic solution is impregnated in the separator 13, the positive electrode 16, and the negative electrode 17.

  Similarly, the first sealing portion 21 is also provided at the edge 15 c of the electrode plate 15 of the negative electrode termination electrode 18 and the positive electrode termination electrode 19, and the negative electrode termination electrode 18, the positive electrode termination electrode 19, and the bipolar electrode 14 are provided between them. Is sealed by the second sealing portion 22. That is, the sealing body 12 has a bonded portion 21 </ b> A bonded to the edge portion 15 c of the outer surface 15 e of the electrode plate 15 of the negative electrode termination electrode 18 as one of the first sealing portions 21. As described above, the internal space V is formed between the negative electrode termination electrode 18 and the positive electrode termination electrode 19 and the bipolar electrode 14, and the electrolytic solution is accommodated in the internal space V.

  FIG. 3 is a schematic cross-sectional view showing a bonding interface between the electrode plate 15 and the first sealing portion 21. As shown in FIG. 3, the surface of the electrode plate 15 is roughened. Here, in each bipolar electrode 14, the entire surface of the electrode plate 15 including the first surface 15a, the second surface 15b, and the end surface shown in FIG. 2 is roughened. The surface of the electrode plate 15 is roughened by, for example, forming a plurality of fine protrusions 15p by electrolytic plating. Similarly, the entire surface of the electrode plate 15 including the inner surface 15d, the outer surface 15e, and the end surface is also roughened for the negative electrode termination electrode 18, and the electrode including the inner surface 15f, the outer surface 15g, and the end surface is also provided for the positive electrode termination electrode 19. The entire surface of the plate 15 is roughened. When the electrode plate 15 is thus roughened, the melted first sealing portion 21 is formed in the concave portion at the bonding interface between the electrode plate 15 and the first sealing portion 21. The anchor effect is exhibited. Thereby, the coupling | bonding force of the electrode plate 15 and the 1st sealing part 21 can be improved. If at least the edge 15c on the first surface 15a (the outer surface 15e for the negative electrode termination electrode 18) is roughened, the effect of improving the bonding force can be obtained. The protrusion 15p has, for example, a shape that tapers from the proximal end side toward the distal end side. In this case, the cross-sectional shape between the adjacent protrusions 15p is an undercut shape, and an anchor effect is likely to occur. FIG. 3 is a schematic diagram, and the shape and density of the protrusions 15p are not particularly limited.

  The power storage device 1 is normally used in a direction in which the stacking direction D substantially coincides with the vertical direction and one end (the negative electrode termination electrode 18 side) of the power storage module 4 is on the upper side (that is, the direction shown in FIG. 1). Even in such a use state, in the power storage module 4, due to a so-called alkali creep phenomenon, the electrolyte L is transmitted along the surface of the electrode plate 15 of the negative electrode termination electrode 18, and a gap between the bonded portion 21 </ b> A and the electrode plate 15 is formed. It may ooze out to the outer surface 15 e side of the electrode plate 15. In FIG. 4, the movement path of the electrolyte L in the alkali creep phenomenon is indicated by an arrow A. The alkali creep phenomenon can occur during charging and discharging of the power storage device 1 and during no load due to electrochemical factors and fluid phenomena. The alkali creep phenomenon is caused by the presence of a negative electrode potential, moisture, and a path for the electrolyte L, respectively.

  In the power storage module 4, the water repellent material 31 is provided on the surface of the edge 15 c of the electrode plate 15 of the negative electrode termination electrode 18 (that is, the region included in the movement path of the electrolyte L due to the alkali creep phenomenon). The water repellent material 31 is formed in a film shape as an example. For example, the water repellent material 31 can be formed by applying a fluorine resin material (for example, “OS-90HF” manufactured by Harves Co., Ltd.), fluorine rubber, a polymer having a fluorine / methyl functional group, or the like. .

  As shown in FIG. 4, the water repellent material 31 has a first portion 31A, a second portion 31B, and a third portion 31C. The first portion 31 </ b> A is provided at the end 15 h of the electrode plate 15 of the negative electrode termination electrode 18. The second portion 31B is provided on the inner surface 15d of the electrode plate 15 of the negative electrode termination electrode 18 continuously with the first portion 31A. The third portion 31C is provided on the outer surface 15e of the electrode plate 15 of the negative electrode termination electrode 18 so as to be continuous with the inner end portion 21a of the bonded portion 21A when viewed from the stacking direction D. All of the first portion 31A, the second portion 31B, and the third portion 31C are formed in a rectangular frame shape along the edge portion 15c of the electrode plate 15 of the negative electrode termination electrode 18 when viewed from the stacking direction D. The width of the second portion 31B and the third portion 31C in the direction orthogonal to the stacking direction D is, for example, about 3 mm. Further, as described above, in the present embodiment, the surface (end portion 15h, inner surface 15d, and outer surface 15e) of the electrode plate 15 of the negative electrode termination electrode 18 is roughened, and therefore the first portion 31A and the second portion 31B. The portion where the third portion 31C is provided is a rough surface provided with a plurality of fine protrusions 15p.

  Then, the manufacturing method of the electrical storage apparatus 1 mentioned above is demonstrated. The manufacturing method of the electrical storage device 1 includes a primary molding process, a stacking process, and a secondary molding process. First, in the primary forming step, a predetermined number of bipolar electrodes 14, a pair of negative electrode termination electrodes 18 and positive electrode termination electrodes 19 are prepared, and the first sealing portion 21 is welded along the edge 15 c of each electrode plate 15. . Subsequently, a water-repellent material 31 (first portion 31A, second portion 31B, and the like) is formed by applying a fluorine-based resin material to the surface (end portion 15h, inner surface 15d, and outer surface 15e) of the electrode plate 15 of the negative electrode termination electrode 18. A third portion 31C) is formed. Note that the step of forming the water repellent material 31 may be performed before the step of forming the first sealing portion 21.

  In the laminating step, the bipolar electrode 14, the negative electrode termination electrode 18, and the positive electrode termination electrode 19 are laminated via the separator 13 so that the first sealing portion 21 is disposed between the edges 15 c of the electrode plate 15. Thus, the electrode laminate 11 is formed. In the secondary molding step, after the electrode laminate 11 is placed in an injection mold (not shown), the molten resin is injected into the mold to surround the first sealing portion 21. 2 The sealing part 22 is formed. Thereby, the sealing body 12 is formed on the side surface 11a of the electrode laminate 11.

  After the secondary forming step, a step of injecting an electrolytic solution into the internal space V between the bipolar electrodes 14, 14, a step of stacking the power storage module 4 and the conductive plate 5 to form the power storage module laminate 2, and a restraining member The power storage device 1 shown in FIG. 1 is obtained through a process of restraining the power storage module stack 2 by 3 and the like.

  Then, the effect of the electrical storage module 4 is demonstrated.

  As described above, in the power storage module 4, the water repellent material 31 is provided on the surface of the edge 15 c of the electrode plate 15 of the negative electrode termination electrode 18 (that is, the region included in the movement path of the electrolyte L due to the alkali creep phenomenon). It has been. In the present embodiment, as an example, the first portion 31A, the second portion 31B, and the third portion 31C are provided on the end portion 15h, the inner surface 15d, and the outer surface 15e of the electrode plate 15. As a result, leakage of the electrolyte L due to the alkali creep phenomenon from the internal space V between the electrode plate 15 of the negative electrode termination electrode 18 and the electrode plate 15 adjacent to the electrode plate 15 is suppressed. As a result, the occurrence of secondary damage such as a short circuit due to the leaked electrolyte L can be suppressed, and the reliability can be improved.

  Specifically, the first portion 31 </ b> A can prevent the electrolyte L from creeping up due to the alkali creep phenomenon at the end h of the electrode plate 15 of the negative electrode termination electrode 18. Thereby, the leakage of the electrolyte solution L due to the alkali creep phenomenon can be accurately suppressed.

  Further, the second portion 31B is further provided in addition to the first portion 31A, so that the electrolyte solution L can be further swung up by the alkali creep phenomenon at the inner surface 15d and the end portion 15h of the electrode plate 15 of the negative electrode termination electrode 18. Further suppression can be achieved.

  Further, the third portion 31C can further suppress leakage of the electrolyte L to the outside due to the alkali creep phenomenon. Specifically, the electrolyte L that is about to flow out through the gap between the welded portion of the bonded portion 21A and the electrode plate 15 of the negative electrode termination electrode 18 can be blocked by the third portion 31C. Furthermore, according to the 3rd part 31C, the penetration | invasion of the water | moisture content from the exterior to the internal space V can also be suppressed. As a result, the generation of an alkali concentration gradient in the vicinity of the welded portion between the bonded portion 21A and the electrode plate 15 of the negative electrode termination electrode 18 is suppressed. As a result, the driving force of alkali creep can be suppressed, and leakage of the electrolyte L can be prevented. Further suppression can be achieved.

In addition, at least a portion of the surface of the negative electrode termination electrode 18 where the water repellent material 31 is provided (in this embodiment, the end 15h, the inner surface 15d, and the outer surface 15e) is a rough surface provided with a plurality of fine protrusions 15p. is there. For this reason, the water repellency of the water repellent material 31 can be improved based on the Cassie-Baxter theory or the like as compared with the case where the water repellent material 31 is provided on a flat surface. Here, the Cassie-Baxter theory is that when the concavo-convex structure (here, the concavo-convex structure formed by the plurality of protrusions 15p) is sufficiently small with respect to the droplets, the material (here, the fluororesin constituting the water repellent material 31). This is a theory that shows that the actual contact angle φ has the following relationship with the contact angle θ inherent to the material.
When θ> 90 °, φ> θ
When θ <90 °, φ <θ

  Here, the contact angle θ of the fluororesin material is usually larger than 90 ° (for example, 120 °). Therefore, by providing the water repellent material 31 on the rough surface as described above, an actual contact angle φ larger than the original contact angle θ of the material can be obtained, so that the water repellency of the water repellent material 31 can be increased. As a result, the access of the alkaline solution (electrolytic solution L) to the main chain (polymer) of the water repellent material 31 and the bonding interface between the water repellent material 31 and the inner surface 15d can be suppressed. The alkali resistance can be improved. Thereby, the creeping-up of the electrolyte solution L due to the alkali creep phenomenon can be further effectively suppressed.

  The water repellent material 31 is made of a fluorine resin material. By forming the water repellent material 31 with a fluororesin material excellent in both water repellency and alkali resistance, leakage of the electrolyte L due to the alkali creep phenomenon can be further effectively suppressed.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the water repellent material 31 includes all of the first portion 31A, the second portion 31B, and the third portion 31C, but the water repellent material 31 includes the first portion 31A, the second portion 31B, and the third portion 31C. It suffices to include at least one of the third portions 31C.

  Moreover, in the said embodiment, although the water repellent material 31 was provided in the rough surface, you may provide in a flat surface. That is, at least a portion of the surface of the negative electrode termination electrode 18 where the water repellent material 31 is provided may be a flat surface. By providing the water repellent material 31 on a flat surface (that is, a surface with very little unevenness), the water repellent material 31 can be formed in a uniform and stable film shape. Thereby, pinholes and the like are less likely to occur in the water repellent material 31. As a result, the creeping of the electrolyte solution L due to the alkali creep phenomenon can be stably suppressed. For example, when the water repellent material 31 includes the above-described second portion 31b, the above-described roughening treatment may be performed only on the outer surface 15e of the surface of the negative electrode termination electrode 18. By performing the roughening process on only one side (outer surface 15e) in this manner, the inner surface 15d provided with the second portion 31b can be a flat surface (that is, the surface not subjected to the roughening process). .

  Moreover, in the said embodiment, although the 1st sealing part 21 was formed only in the 1st surface 15a side of the electrode plate 15, the 1st sealing part 21 is the 1st surface 15a side and the 2nd surface 15b side. For example, the edge 15c of the electrode plate 15 may be formed so as to be buried in the first sealing portion 21. Or the 1st sealing part 21 may be formed only in the 2nd surface 15b side. For example, when the bonded portion 21A is not formed on the outer surface 15e of the electrode plate 15 of the negative electrode termination electrode 18, one of the second sealing portions 22 of the sealing body 12 projecting inward at one end in the stacking direction D. The portion may be bonded to the outer surface 15e as the above-described bonded portion. Moreover, in the said embodiment, although one part of the outer side of the 1st sealing part 21 protruded outside from the electrode plate 15, the 1st sealing part 21 is arrange | positioned between the edge parts 15c of the electrode plate 15 at least. For example, the entire first sealing portion 21 may be disposed between the edge portions 15 c of the electrode plate 15.

  DESCRIPTION OF SYMBOLS 1 ... Power storage device, 4 ... Power storage module, 11 ... Electrode laminated body (laminated body), 11a ... Side surface, 12 ... Sealing body, 13 ... Separator, 14 ... Bipolar electrode, 15 ... Electrode plate, 15a ... 1st surface, 15b ... second surface, 15c ... edge, 15d ... inner surface, 15e ... outer surface, 15h ... end, 15p ... projection, 16 ... positive electrode, 17 ... negative electrode, 18 ... negative electrode termination electrode, 21A ... joined part, 21a ... Inner end, 31 ... water repellent material, 31A ... first part, 31B ... second part, 31C ... third part, D ... stacking direction, V ... inner space.

Claims (7)

A laminate including a plurality of electrodes laminated via a separator;
A sealing body that is provided on a side surface of the stacked body and seals between the electrodes adjacent to each other in the stacking direction of the stacked body;
With
In the internal space formed between the electrodes adjacent in the stacking direction, an electrolytic solution made of an alkaline solution is accommodated,
The electrode includes a plurality of bipolar electrodes and a negative electrode termination electrode,
The bipolar electrode includes an electrode plate, a positive electrode provided on a first surface of the electrode plate, and a negative electrode provided on a second surface opposite to the first surface of the electrode plate,
The negative electrode termination electrode includes an electrode plate having the negative electrode formed on the inner surface, and is disposed at one end of the laminate in the stacking direction,
A water repellent material is provided on the surface of the edge of the electrode plate of the negative electrode termination electrode.
Power storage module. The water repellent material has a first portion provided at an end portion of the electrode plate of the negative electrode termination electrode.
The power storage module according to claim 1. The water repellent material has a second portion provided on the inner surface of the electrode plate of the negative electrode termination electrode continuously with the first portion,
The power storage module according to claim 2. The sealing body has a bonded portion bonded to an outer edge of the electrode plate of the negative electrode termination electrode,
The water repellent material has a third portion provided on the outer surface so as to be continuous with the inner end portion of the bonded portion when viewed from the stacking direction.
The electrical storage module as described in any one of Claims 1-3. Of the surface of the negative electrode termination electrode, at least a portion where the water repellent material is provided is a rough surface provided with a plurality of fine protrusions.
The electrical storage module as described in any one of Claims 1-4. Of the surface of the negative electrode termination electrode, at least a portion where the water repellent material is provided is a flat surface.
The electrical storage module as described in any one of Claims 1-4. The water repellent material is formed of a fluorine resin material,
The electrical storage module as described in any one of Claims 1-6.

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