JP7014688B2 - Power storage module - Google Patents

Description

The present invention relates to a power storage module.

As a conventional power storage module, a bipolar battery including a bipolar electrode having a positive electrode formed on one surface of an electrode plate and a negative electrode formed on the other surface is known (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

By the way, in the power storage module as described above, a negative electrode terminal electrode having a negative electrode formed inside the electrode laminate is arranged at one end of the electrode laminate in the stacking direction. The electrode plate of the negative electrode terminal electrode is also sealed by a sealant, but when the electrolytic solution contains an alkaline solution, the electrolytic solution is transmitted to the surface of the electrode plate of the negative electrode terminal electrode due to the so-called alkaline creep phenomenon. , It may occur that it passes between the sealing body and the electrode plate and seeps out to the outside of the power storage module. If the electrolytic solution leaks to the outside of the power storage module and diffuses, for example, corrosion of the conductive plate arranged in contact with the power storage module or short circuit between the power storage module and the restraint member may occur, which is a factor that reduces reliability. Can be.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a power storage module capable of suppressing the electrolytic solution from seeping out of the power storage module due to an alkaline creep phenomenon.

The power storage module according to one aspect of the present invention includes an electrode laminate including a laminate of a plurality of bipolar electrodes and a negative electrode terminal electrode arranged on one end side in the stacking direction of the laminate, and an electrode laminate. It is provided so as to surround the side surface of the body, and includes a sealing body that forms an internal space between adjacent electrodes and seals the internal space, and an electrolytic solution containing an alkaline solution contained in the internal space. The encapsulant includes a frame-shaped resin portion that is arranged between adjacent electrodes and is coupled to the edge of the electrode plate of the electrode, and the electrode plate and the resin portion of the negative electrode terminal electrode are frame-shaped first. The coupling region is connected by a frame-shaped second coupling region that surrounds the outside of the first coupling region with a predetermined interval, and an extra space is formed between the first coupling region and the second coupling region.

In this power storage module, the electrode plate of the negative electrode terminal electrode and the resin portion are coupled by a frame-shaped first coupling region and a frame-shaped second coupling region that surrounds the outside of the first coupling region with a predetermined interval. , An extra space is formed between the first coupling region and the second coupling region. Since this surplus space is formed between the first bond region and the second bond region, it is located on the movement path of the electrolytic solution due to the alkaline creep phenomenon. As a result, it is possible to prevent moisture contained in the external air from entering the inside of the power storage module through the gap between the electrode plate of the negative electrode terminal electrode and the resin portion. Therefore, since the influence of external humidity, which is a condition for accelerating the alkaline creep phenomenon, is suppressed, it is possible to suppress the electrolytic solution from seeping out to the outside of the power storage module.

The electrode laminate further has a metal plate arranged outside the laminating direction with respect to the electrode plate of the negative electrode terminal electrode, and another surplus space is formed by the encapsulant, the electrode plate of the negative electrode terminal electrode, and the metal plate. It may have been done. According to this configuration, in addition to the surplus space, another surplus space is provided on the movement path of the electrolytic solution due to the alkaline creep phenomenon. Therefore, it is possible to more reliably suppress the entry of water contained in the external air into the gap between the electrode plate of the negative electrode terminal electrode, which is the starting point of the electrolytic solution, and the resin portion.

In the first coupling region and the second coupling region, the electrode plate of the negative electrode terminal electrode may be roughened. According to this configuration, it is possible to improve the bonding strength between the electrode plate of the negative electrode terminal electrode and the resin portion in the first coupling region and the second coupling region by the anchor effect.

According to the present invention, there is provided a power storage module capable of suppressing the electrolytic solution from seeping out of the power storage module due to the alkaline creep phenomenon.

It is a schematic sectional drawing which shows the power storage device which concerns on one Embodiment. FIG. 3 is a schematic cross-sectional view showing the internal configuration of the power storage module shown in FIG. 1. It is an enlarged sectional view which shows a part of the power storage module of FIG. It is a figure which shows schematicly about the power storage module seen from the stacking direction. It is a partially enlarged sectional view of the power storage module which concerns on a comparative example. It is a schematic sectional drawing which shows the internal structure of the power storage module which concerns on the modification. It is a figure which shows the modification of the 1st connection region and the 2nd connection region schematicly.

Hereinafter, various embodiments will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

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 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 nickel-metal hydride secondary battery, a secondary battery such as a lithium ion secondary battery, an electric double layer capacitor, or the like. In the following description, a nickel-metal hydride secondary battery will be illustrated.

The storage modules 4 adjacent to each other in the stacking direction 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 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 with each other in the stacking direction. 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 intersecting (orthogonal) with, for example, the stacking direction and the drawing direction of the positive electrode terminal 6 and the negative electrode terminal 7. The conductive plate 5 functions as a connecting member that electrically connects the power storage modules 4 to each other, and also serves as a heat dissipation plate that dissipates heat generated by the power storage module 4 by circulating a refrigerant through these flow paths 5a. It also has a function. In the example of FIG. 1, the area of the conductive plate 5 seen 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 power storage module. It may be the same as the area of 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, 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 when viewed from 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 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, and is attached to the tip portion of the fastening bolt 9 protruding from the insertion hole 8a of the other end plate 8. , The nut 10 is screwed. As a result, the power storage module 4 and the conductive plate 5 are sandwiched by the end plate 8 to be unitized as the module laminate 2, and a restraining 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. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the power storage module shown in FIG. FIG. 3 is an enlarged cross-sectional view showing a part of the power storage module of FIG. As shown in FIGS. 2 and 3, 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 has an electrode 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. ing. The positive electrode 16 is a positive electrode active material layer formed by applying a positive electrode active material to the electrode plate 15. The negative electrode 17 is a negative electrode active material layer formed by applying a 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. It is preferable that the separator 13 extends in a direction intersecting the stacking direction D so as to come into contact with the first sealing portion 21 described later. This makes it possible to suppress a short circuit between the electrodes.

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 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 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, and is electrically connected to the other conductive plate 5 (see FIG. 1) adjacent to the power storage module 4. It is connected.

The electrode plate 15 is made of a metal such as nickel or a nickel-plated steel plate. As an example, the electrode plate 15 is a rectangular metal leaf made of nickel. 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 on a sheet, 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, polypropylene, methyl cellulose and the like, or a non-woven fabric. The separator 13 may be reinforced with a vinylidene fluoride resin compound. The separator 13 is not limited to a sheet shape, and a bag shape may be used.

The sealing body 12 is formed into a rectangular cylinder 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 21 (resin portions) 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 includes 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, alkaline-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 annular shape when viewed from the stacking direction D. The first sealing portion 21 is welded to one surface 15a of the electrode plate 15 by, for example, ultrasonic waves or heat, 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.

The region where the edge portion 15c and the first sealing portion 21 overlap on one surface 15a of the electrode plate 15 is the 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. The roughened region may be only the coupling region K, but in the present embodiment, the entire one surface 15a of the electrode plate 15 is roughened. Roughening can be achieved, for example, by forming a plurality of protrusions by electrolytic plating. Since a plurality of protrusions can be formed on the one surface 15a, at the bonding interface with the first sealing portion 21 on the one surface 15a, the molten resin enters between the plurality of protrusions formed by the roughening and anchors. The effect is exhibited. Thereby, the bond strength between the electrode plate 15 and the first sealing portion 21 can be improved. The protrusions formed during roughening have, for example, a shape that becomes thicker from the proximal end side toward the distal end side. As a result, the cross-sectional shape between the adjacent protrusions becomes an undercut shape, and the anchor effect can be enhanced.

The second sealing portion 22 is provided on the outside of the electrode laminate 11 and the first sealing portion 21, and constitutes the 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 tubular shape (annular 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 located between the bipolar electrodes 14 adjacent to each other along the stacking direction D, and the negative electrode termination electrodes adjacent to each other along the stacking direction D. The space between the 18 and the bipolar electrode 14 and the space 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 termination electrode 18 and the bipolar electrode 14, and between the positive electrode termination electrode 19 and the bipolar electrode 14. ing. The internal space V contains 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.

Next, with reference to FIGS. 3 and 4, the coupling region K between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21 will be described in more detail. As shown in FIGS. 3 and 4, the coupling region K includes a first coupling region K1 and a second coupling region K2, and includes an electrode plate 15 of the negative electrode terminal 18 and a first sealing portion 21. Is bound by a first binding region K1 and a second binding region K2. Both the first coupling region K1 and the second coupling region K2 are rectangular frame-shaped regions, and the second coupling region K2 totally surrounds the outside of the first coupling region K1 with a predetermined interval. The region between the first coupling region K1 and the second coupling region K2 is a region in which the electrode plate 15 of the negative electrode termination electrode 18 and the first sealing portion 21 are not coupled to each other, and the surplus space VC is in this region. Is formed. The surplus space VC is a closed space in which the electrolytic solution is not housed. Seen from the stacking direction D, the surplus space VC is formed in a rectangular frame shape over the entire circumference of the first sealing portion 21 between the first coupling region K1 and the second coupling region K2.

In the present embodiment, the width H2 of the second coupling region K2 (the direction orthogonal to the stacking direction D and from the inside to the outside of the power storage module 4) is larger than the width H1 of the first coupling region K1. As an example, the width H1 of the first coupling region K1 can be 1 mm or more and 20 mm or less, and the width H2 of the second coupling region K2 can be 1 mm or more and 20 mm or less. The relationship between the width H1 of the first coupling region K1 and the width H2 of the second coupling region K2 is not particularly limited. For example, the width H1 of the first coupling region K1 may be larger than the width H2 of the second coupling region K2, and the width H1 of the first coupling region K1 and the width H2 of the second coupling region K2 are substantially the same as each other. You may.

Further, the width of the region between the first coupling region K1 and the second coupling region K2 (that is, the width H3 of the surplus space VC) can be, for example, 1 mm or more and 10 mm or less. The width H3 of the surplus space VC can be adjusted by changing the width H1 of the first coupling region K1 and / or the width H2 of the second coupling region K2. For example, by making the width H1 of the first coupling region K1 and the width H2 of the second coupling region K2 smaller than the width H3 of the surplus space VC, the width H3 of the surplus space VC can be made relatively large. In this case, since the volume of the surplus space VC becomes large, the ratio of the amount of water to the volume of the surplus space VC is relatively small even if the water contained in the outside air enters the surplus space VC. Therefore, the influence of the invading moisture can be reduced. On the contrary, by making the width H1 of the first coupling region K1 and the width H2 of the second coupling region K2 larger than the width H3 of the surplus space VC, the width H3 of the surplus space VC can be made relatively small. In this case, since the volume of the surplus space VC becomes small, the amount of air contained in the surplus space VC at the time of manufacturing the power storage module 4 becomes small. As a result, the amount of water contained in the surplus space VC can be reduced in advance, so that the electrolytic solution seeps into the surplus space VC from between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21. Can be suppressed. The width H3 of the surplus space VC is a method of changing the width H1 of the first coupling region K1 and the width H2 of the second coupling region K2, as well as the positions of the first coupling region K1 and the second coupling region K2 in the width direction. It can also be adjusted by the method of changing in.

Subsequently, the operation and effect of the power storage module 4 will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view of a main part of the power storage module according to the comparative example. As shown in FIG. 5, in the power storage module 100 according to the comparative example, the entire region where the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21 overlap is coupled (that is, the first coupling region K1 and the first coupling region K1 and the first. It does not have a two-bonding region K2), and it does not have a surplus space VC in which the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21 are not coupled. It is different from module 4.

In the power storage module 100, the electrolytic solution existing in the internal space V propagates on the surface of the electrode plate 15 of the negative electrode terminal 18 due to the so-called alkaline creep phenomenon, and is between the electrode plate 15 and the first sealing portion 121A in the coupling region K. It may seep out to the one side 15a side of the electrode plate 15 through the gap between the two. In FIG. 4, the movement path of the electrolytic solution L in the alkaline creep phenomenon is shown by an arrow A. This alkaline creep phenomenon can occur during charging, discharging, and no load of the power storage device due to electrochemical factors, fluid phenomena, and the like. The alkaline creep phenomenon occurs due to the presence of each of the negative electrode potential, the water content, and the passage of the electrolytic solution L, and progresses with the passage of time.

On the other hand, in the power storage module 4 according to the present embodiment, the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21 are frame-shaped first coupling region K1 and the outside of the first coupling region K1. Is connected to the frame-shaped second coupling region K2 that surrounds the first coupling region K1 with a predetermined interval, and a surplus space VC is formed between the first coupling region K1 and the second coupling region K2. Since this surplus space VC is formed between the first bond region K1 and the second bond region K2, it is located on the movement path of the electrolytic solution due to the alkaline creep phenomenon. As a result, it is possible to prevent moisture contained in the external air from entering the inside of the power storage module 4 through the gap between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21. Therefore, since the influence of external humidity, which is an acceleration condition of the alkaline creep phenomenon, is suppressed, it is possible to suppress the electrolytic solution from seeping out to the outside of the power storage module 4.

Further, in the first coupling region K1 and the second coupling region K2, the electrode plate 15 of the negative electrode terminal electrode 18 is roughened. As a result, the bonding strength between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21 in the first coupling region K1 and the second coupling region K2 can be improved by the anchor effect. Therefore, it is possible to suppress the formation of a gap between the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21 due to the deformation of the negative electrode terminal 18 due to an increase in internal pressure or the like, and the electrolytic solution is a storage module. It is possible to suppress the exudation to the outside of 4.

Next, with reference to FIG. 6, the power storage module 40 according to the modified example will be described. FIG. 6 is a schematic cross-sectional view showing the internal configuration of the power storage module 40 according to the modified example. Similar to the power storage module 4, the power storage module 40 includes an electrode laminate 11 and a resin sealant 12 that seals the electrode stack 11. The electrode laminate 11 is composed of a plurality of electrodes laminated along the stacking direction D 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 coupling region K between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21 includes the first coupling region K1 and the second coupling region K2, and the first coupling region K1 and the second coupling region K2. A surplus space VC (not shown) is formed between them. The power storage module 40 is different from the power storage module 4 in that the electrode laminate 11 further has a metal plate 20.

The metal plate 20 is arranged outside the stacking direction D with respect to the electrode plate 15 of the negative electrode terminal electrode 18. The metal plate 20 has a other surface 20b facing the one surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18 and one surface 20a on the opposite side of the other surface 20b. The positive electrode active material and the negative electrode active material are not coated on one surface 20a and the other surface 20b of the metal plate 20, and the entire surfaces of the one surface 20a and the other surface 20b are uncoated areas. That is, in the present 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 on the negative electrode termination electrode 18 side and is in contact with the electrode plate 15 of the negative electrode termination electrode 18. More specifically, in the contact portion C, the other surface 20b of the metal plate 20 is in contact with the one surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18, and the one surface 20a of the metal plate 20 is the conductive plate 5 (see FIG. 1). ) Is in contact. As a result, the negative electrode 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 a metal such as nickel or a nickel-plated steel plate.

The region where the edge portion 20c and the first sealing portion 21 on one surface 20a and the other surface 20b of the metal plate 20 overlap is roughened in the same manner as the surface of the electrode plate 15 of the negative electrode terminal electrode 18. The roughened region may be only the region where the edge portion 20c and the first sealing portion 21 are bonded, 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 first sealing portion 21 is bonded to each of the edge portions 20c on one surface 20a and the other surface 20b of the metal plate 20. As a result, a surplus space VA (another surplus space) in which the electrolytic solution is not accommodated is formed by the first sealing portion 21, the electrode plate 15 of the negative electrode terminal electrode 18, and the metal plate 20. Seen from the stacking direction D, the surplus space VA is formed so as to surround the periphery of the contact portion C. Further, when viewed from the 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. Is doing.

Further, the power storage module 40 further has another surplus space VB in which the electrolytic solution is not housed. Another surplus space VB is located outside the stacking direction D with respect to the surplus space VA. The surplus space VB is formed by the electrode plate 15 of the negative electrode terminal electrode 18, the first sealing portion, and the second sealing portion 22. The surplus space VB is formed so as to surround the outside of the edge portion 20c of the metal plate 20. The surplus space VB has a substantially rectangular shape when viewed from the cross section along the stacking direction D.

As described above, also in the power storage module 40, the coupling region K between the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21 includes the first coupling region K1 and the second coupling region K2, and is the first. A surplus space VC is formed between the binding region K1 and the second binding region K2. Since this surplus space VC is located on the movement path of the electrolytic solution due to the alkaline creep phenomenon, the moisture contained in the outside air is transferred to the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21. It is possible to suppress the entry into the inside of the power storage module 4 through the gap between them. Therefore, similarly to the power storage module 4, it is possible to prevent the electrolytic solution from seeping out of the power storage module 40.

Further, the electrode laminated body 11 further has a metal plate 20 arranged outside the stacking direction D with respect to the electrode plate of the negative electrode terminal 18, and the sealing body 12, the electrode plate 15 of the negative electrode terminal 18, and the metal. Another surplus space VA is formed by the plate 20. As a result, in addition to the surplus space VC, another surplus space VA is provided on the movement path of the electrolytic solution due to the alkaline creep phenomenon. Therefore, the moisture contained in the outside air is prevented from entering the gap between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21 (sealing body 12), which is the starting point for the electrolytic solution to seep out. It can be suppressed more reliably.

Further, in the power storage module 40, another surplus space VB is further formed outside the stacking direction D by the sealing body 12 and the metal plate 20 as compared with the other surplus space VA. As a result, in addition to the surplus space VC and other surplus space VA, another surplus space VB due to the sealing body 12 and the metal plate 20 is further provided on the movement path of the electrolytic solution due to the alkaline creep phenomenon. Therefore, it is possible to more reliably suppress the entry of moisture contained in the outside air into the gap between the electrode plate 15 of the negative electrode terminal electrode 18 and the first sealing portion 21, which is the starting point for the electrolytic solution to seep out.

Next, with reference to FIG. 7, a modification of the coupling region K between the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21 will be described. FIG. 7 is a diagram schematically showing a modified example of the coupling region K between the electrode plate of the negative electrode terminal electrode and the first sealing portion. As shown in FIG. 7, the coupling region K'according to the modified example is different from the coupling region K in that each side of the first coupling region K1 extends to the second coupling region K2. As a result, the surplus space VC is divided into eight spaces VC1 to VC8. The spaces VC1 to VC4 are spaces extending in a direction parallel to each side of the first coupling region K1, and the spaces VC5 to VC8 are the corners of the first coupling region K1 and the corners of the second coupling region K2. It is a space located between.

Even in the power storage module having the coupling region K'according to the modified example, since the surplus space VC is formed in the region between the first coupling region K1 and the second coupling region K2, the same operation and effect as that of the storage module 4 Can be obtained. Further, when each side of the first coupling region K1 extends to the second coupling region K2, the first coupling region K1 can be formed one side at a time. By forming the first coupling region K1 side by side in this way, it is not necessary to use a joining device having a rectangular annular heating portion (that is, it is possible to use a general joining device having a linear heating portion. Therefore, it is possible to easily connect the electrode plate 15 of the negative electrode terminal 18 to the first sealing portion 21 and form the surplus space VC.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, in the above embodiment, an example in which one surplus space VC is formed by the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21 has been described, but the coupling region K has more frames. It may include a shape-like bonding region. For example, the binding region K may further include a frame-shaped third binding region (not shown) surrounding the second binding region K2 outside the second binding region K2. In this case, a surplus space can be further formed in the region between the second coupling region K2 and the third coupling region outside the surplus space VC. In this way, by increasing the number of other frame-shaped coupling regions that surround the inner coupling region as a whole, a larger amount of surplus space can be formed. It is possible to more reliably suppress the entry of moisture contained in the air.

Further, in the power storage module 40 in which the electrode laminate 11 has the metal plate 20, the coupling region between the metal plate 20 and the first sealing portion 21 also includes the first coupling region and the second coupling region, and is the first coupling. An extra space may be formed between the region and the second coupling region.

Further, in the above embodiment, an example in which the electrode plate 15 of the negative electrode termination electrode 18 is roughened in the first coupling region K1 and the second coupling region K2 has been described, but the electrode plate 15 of the negative electrode termination electrode 18 has been described. Does not have to be roughened.

Further, the rectangular frame-shaped first sealing portion 21 may be coupled to the other surface 15b side of the electrode plate 15 of the positive electrode terminal electrode 19. The first sealing portion 21 may also be coupled to another first sealing portion 21 by the second sealing portion 22. Further, the edge portion of the first sealing portion 21 coupled to the other surface 15b side of the electrode plate 15 of the positive electrode terminal electrode 19 and the first sealing portion 21 on the one surface 15a side of the electrode plate 15 of the positive electrode terminal electrode 19. It may be bonded to the edge portion of the above by hot plate welding or the like.

4,40 ... Energy storage module, 11 ... Electrode laminate, 11a ... Side surface, 12 ... Sealed body, 14 ... Bipolar electrode, 15 ... Electrode plate, 15c ... Edge, 18 ... Negative electrode termination electrode, 20 ... Metal plate, 21 ... 1st sealing part (resin part), 22 ... 2nd sealing part, D ... stacking direction, K1 ... first bonding region, K2 ... second bonding region, V ... internal space, VA ... surplus space (other Surplus space), VC ... Surplus space.

Claims (3)

An electrode laminated body including a laminated body of a plurality of bipolar electrodes and a negative electrode terminal electrode arranged on one end side of the laminated body in the stacking direction.
A sealing body provided so as to surround the side surface of the electrode laminate, forming an internal space between adjacent electrodes and sealing the internal space.
An electrolytic solution containing an alkaline solution contained in the internal space is provided.
The encapsulating body includes a frame-shaped resin portion arranged between the adjacent electrodes and bonded to the edge portion of the electrode plate of the electrodes.
The electrode plate of the negative electrode terminal electrode and the resin portion are connected by a frame-shaped first coupling region and a frame-shaped second coupling region that surrounds the outside of the first coupling region with a predetermined interval.
A power storage module in which a surplus space is formed between the first coupling region and the second coupling region. The electrode laminate further has a metal plate arranged outside the stacking direction with respect to the electrode plate of the negative electrode terminal electrode.
The power storage module according to claim 1, wherein another surplus space is formed by the sealing body, the electrode plate of the negative electrode terminal electrode, and the metal plate. The power storage module according to claim 1 or 2, wherein the negative electrode terminal electrode is roughened in the first coupling region and the second coupling region.

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