JP6989461B2 - 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, short circuit between the power storage module and the restraint member, etc. 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. An electrode is provided with a sealing body that is provided so as to surround the side surface of the electrode and 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 laminated body has a metal plate arranged outside in the stacking direction with respect to the electrode plate of the negative electrode terminal electrode, and a first surplus space is formed by the sealed body, the electrode plate of the negative electrode terminal electrode, and the metal plate. A second surplus space is formed by the encapsulant and the metal plate, the size of the metal plate is smaller than the size of the electrode plate of the electrode when viewed from the stacking direction, and the outer edge of the metal plate is inside the outer edge of the electrode plate. To position.

In this power storage module, the first surplus space is formed by the encapsulating body, the electrode plate of the negative electrode terminal electrode, and the metal plate, and the second surplus space is formed by the encapsulating body and the metal plate. Further, when viewed from the stacking direction, the size of the metal plate is smaller than the size of the electrode plate of the electrode, and the outer edge of the metal plate is located inside the outer edge of the electrode plate. As a result, the second surplus space formed by the sealing body and the metal plate is larger than that in the case where the size of the metal plate is substantially the same as the size of the electrode plate of the electrode. Due to the large size of the second surplus space, the ratio of the amount of water to the volume of the second surplus space even when the water contained in the air invades the second surplus space. Is relatively small, so the effect of invading moisture is reduced. 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 leakage of the electrolytic solution to the outside of the power storage module.

The volume of the second surplus space may be larger than that of the first surplus space. As described above, since the second surplus space is larger than the first surplus space, even when the moisture contained in the air invades into the second surplus space, the second surplus space is reached. Since the ratio of the amount of water to the volume of the space is relatively small, the influence of the invading water is reduced. 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 leakage of the electrolytic solution to the outside of the power storage module.

The encapsulating body includes a resin portion arranged between adjacent electrodes and a sealing portion for connecting the resin portions so as to surround the side surface of the electrode laminate, and the encapsulating portion is a laminate of electrode laminates. At both ends of the direction, there are extending portions extending in a direction intersecting the stacking direction toward the inside of the electrode laminate, and the end position of the extending portion is inside the end position of the metal plate when viewed from the stacking direction. It may be. According to this configuration, a portion where the extended portion and the metal plate overlap each other is formed when viewed from the stacking direction. Therefore, even if the internal pressure of the power storage module increases, the extended portion deforms the metal plate. Can be suppressed. Therefore, it is possible to suppress the formation of a gap between the resin portion and the metal plate due to the deformation of the metal plate or the like, and it is possible to prevent the electrolytic solution from seeping out to the outside of the power storage module.

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 schematically 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.

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 stack 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 power 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 functions. 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 laminated body 2, and a restraining load is applied to the module laminated body 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 of the electrode laminate 11 in the stacking direction D, and is electrically connected to one conductive plate 5 (see FIG. 1) adjacent to the power storage module 4. It is connected to the. The negative electrode 17 provided on the other surface 15b of the electrode plate 15 of the negative electrode terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D via the separator 13.

The positive electrode terminal electrode 19 has an electrode plate 15 and a positive electrode 16 provided on one surface 15a of the electrode plate 15. The positive electrode terminal electrode 19 is arranged at the other end of the stacking direction D so that one surface 15a faces the center side of the stacking direction D in the electrode laminated body 11. The positive electrode 16 provided on one surface 15a of the positive electrode terminal electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D via the separator 13. The other surface 15b of the electrode plate 15 of the positive electrode terminal electrode 19 constitutes the other outer surface of the electrode laminate 11 in the stacking direction, 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 foil 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. An electrolytic solution (not shown) containing an alkaline solution such as an aqueous potassium hydroxide solution is housed in the internal space V. The electrolytic solution is impregnated in the separator 13, the positive electrode 16, and the negative electrode 17.

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. 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. 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. As a result, the surplus space VA (first 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 4 is a surplus space VB (second sealing portion 21) surrounded by the sealing body 12 (first sealing portion 21 and the second sealing portion 22) and the metal plate 20 and not containing the electrolytic solution. It has a surplus space). 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 shown in FIGS. 3 and 4, the size of the metal plate 20 is smaller than the size of the electrode plate 15 of the electrodes (bipolar electrode 14, negative electrode terminal electrode 18, and positive electrode terminal 19) when viewed from the stacking direction D. It has become. Further, the outer edge 20d of the metal plate 20 is located inside the outer edge 15d of the electrode plate 15. In the present embodiment, the metal plate 20 and the electrode plate 15 are arranged so that their centers are substantially aligned with each other when viewed from the stacking direction D. As an example, the size of the metal plate 20 is smaller than that of the electrode plate 15, but the size of the portion overlapping with the first sealing portion 21 can be 1 mm or more and 5 mm or less. As described above, since the size of the metal plate 20 is smaller than the size of the electrode plate 15, the volume of the surplus space VB is larger than the volume of the surplus space VA. In the present embodiment, the dimensions of the electrode plate 15 of the bipolar electrode 14, the dimensions of the electrode plate 15 of the negative electrode terminal 18 and the dimensions of the electrode plate 15 of the positive electrode 19 are all substantially the same, and are from the stacking direction D. As seen, the outer edges 15d of the electrode plates 15 of each electrode are substantially the same.

Further, the second sealing portion 22 has extending portions 22A extending in a direction intersecting (orthogonal) with the stacking direction D toward the inside of the electrode laminated body 11 at both ends of the stacking direction D of the electrode laminated body 11. ing. The extending portion 22A is continuously provided over the entire circumference of the first sealing portion 21 on the outside of the stacking direction D of the first sealing portion 21, and forms a rectangular annular shape when viewed from the stacking direction D. .. The end position 22d of the extending portion 22A is inside the end position (that is, the outer edge 20d) of the metal plate 20 when viewed from the stacking direction. In other words, when viewed from the stacking direction D, the outer edge 20d of the metal plate 20 is located between the outer edge 15d of the electrode plate 15 and the end position 22d of the extending portion 22A.

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, the power storage module 100 according to the comparative example does not have the metal plate 20 arranged at one end of the electrode laminate 11 in the stacking direction D, and the negative electrode terminal electrode 18 is the electrode laminate 11. It is different from the power storage module 4 according to the present embodiment in that it is located at one end of the above.

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 electrode 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, the electrode laminated body 11 of the power storage module 4 has a metal plate 20, and a surplus space VA is formed by the sealing body 12, the electrode plate 15 of the negative electrode terminal electrode 18, and the metal plate 20, and the sealing body 12 is formed. And the metal plate 20 form an extra space VB. As described above, the extra space VA and the surplus space VB are formed on the movement path of the electrolytic solution due to the alkaline creep phenomenon, so that the extra space VA and the excess space VB are formed between the electrode plate 15 of the negative electrode terminal electrode 18 which is the starting point where the electrolytic solution exudes. It is possible to prevent moisture contained in the outside air from entering the gap. Further, when viewed from the stacking direction D, the size of the metal plate 20 is smaller than the size of the electrode plate 15 of the electrode, and the outer edge 20d of the metal plate 20 is located inside the outer edge 15d of the electrode plate 15. As a result, the surplus space VB formed by the sealing body 12 and the metal plate 20 is larger than that in the case where the size of the metal plate 20 is substantially the same as the size of the electrode plate 15 of the electrode. Since the surplus space VB is large in this way, the ratio of the amount of water to the volume of the surplus space VB becomes relatively small even when the water contained in the air enters the surplus space VB. Therefore, the influence of the invading moisture is reduced. 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, the surplus space VB is larger than the surplus space VA. As described above, since the surplus space VB is larger than the surplus space VA, the ratio of the amount of water to the volume of the surplus space VB even when the water contained in the air enters the surplus space VB. Is relatively small, so the effect of invading moisture is reduced. 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, the sealing body 12 has a first sealing portion 21 arranged between adjacent electrodes and a second sealing portion that connects the first sealing portions 21 to each other so as to surround the side surface 11a of the electrode laminated body 11. 22 and the second sealing portion 22 have extending portions 22A extending in a direction intersecting the stacking direction D toward the inside of the electrode laminated body 11 at both ends of the stacking direction D of the electrode laminated body 11. However, when viewed from the stacking direction D, the end position 22d of the extending portion 22A is inside the end position (outer edge 20d) of the metal plate 20. As a result, a portion where the extending portion 22A and the metal plate 20 overlap each other is formed when viewed from the stacking direction D. Therefore, even when the internal pressure of the power storage module 4 increases, the extending portion 22A causes the metal plate. 20 deformations can be suppressed. Therefore, it is possible to suppress the formation of a gap between the first sealing portion 21 and the metal plate 20 due to the deformation of the metal plate 20, and to prevent the electrolytic solution from seeping out of the power storage module 4. can.

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, the example in which the surplus space VB is larger than the surplus space VA has been described, but the size of the surplus space VB may be substantially the same as the surplus space VA or smaller than the surplus space VA. You may.

Further, in the above embodiment, an example in which the end position 22d of the extending portion 22A is located inside the outer edge 20d of the metal plate 20 when viewed from the stacking direction D has been described, but the end position of the extending portion 22A has been described. 22d is not particularly limited. For example, when viewed from the stacking direction D, the end position 22d of the extending portion 22A may substantially coincide with the outer edge 20d of the metal plate 20, or may be located outside the outer edge 20d of the metal plate 20. good.

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 ... Energy storage module, 11 ... Electrode laminate, 11a ... Side surface, 12 ... Sealed body, 14 ... Bipolar electrode, 15d ... Outer edge, 18 ... Negative terminal terminal electrode, 20 ... Metal plate, 20d ... Outer edge, 21 ... First seal Stop portion (resin portion), 22 ... second sealing portion (sealing portion), 22A ... extending portion, 22d ... end position, D ... stacking direction, V ... internal space, VA ... surplus space (first) Surplus space), VB ... Surplus space (second 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 electrode laminate has a metal plate arranged outside the stacking direction with respect to the electrode plate of the negative electrode terminal electrode.
A first surplus space is formed by the sealing body, the electrode plate of the negative electrode terminal electrode, and the metal plate.
A second surplus space is formed by the sealing body and the metal plate, and the second surplus space is formed.
A power storage module in which the size of the metal plate is smaller than the size of the electrode plate of the electrode when viewed from the stacking direction, and the outer edge of the metal plate is located inside the outer edge of the electrode plate. The power storage module according to claim 1, wherein the second surplus space has a larger volume than the first surplus space. The sealing body includes a resin portion arranged between the adjacent electrodes and a sealing portion for binding the resin portions so as to surround the side surface of the electrode laminate.
The sealing portion has extending portions extending in a direction intersecting the stacking direction toward the inside of the electrode laminate at both ends of the electrode laminate in the stacking direction.
The power storage module according to claim 1 or 2, wherein the end position of the extending portion is inside the end position of the metal plate when viewed from the stacking direction.

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