JP7056464B2 - Manufacturing method of power storage module and power storage module - Google Patents

Description

The present invention relates to a method for manufacturing a power storage module and 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 to provide a method for manufacturing a power storage module and 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 purpose.

The method for manufacturing a power storage module according to one aspect of the present invention is a first method in which a resin portion is bonded to an edge portion of an electrode plate of a bipolar electrode, an edge portion of an electrode plate of a negative electrode terminal electrode, and an edge portion of a metal plate, respectively. The second step of laminating a plurality of bipolar electrodes with a resin portion and laminating a negative electrode terminal electrode with a resin portion and a metal plate with a resin portion, and a resin portion and a resin portion of the negative electrode terminal electrode with a resin portion. It has a third step of coupling the metal plate of the attached metal plate to form an extra space due to the resin portion between the electrode plate of the negative electrode termination electrode and the metal plate, and in the third step, the negative electrode termination The resin portion of the negative electrode terminal electrode with a resin portion and the metal plate of the metal plate with a resin portion are coupled while the space between the electrode plate and the metal plate of the electrode is depressurized from the atmospheric pressure.

In the method of manufacturing this power storage module, the resin portion of the negative electrode terminal electrode with a resin portion and the metal plate of the metal plate with the resin portion are coupled, and the surplus space due to the resin portion is provided between the electrode plate of the negative electrode terminal electrode and the metal plate. In the third step, the space between the electrode plate and the metal plate of the negative electrode terminal electrode is depressurized from the atmospheric pressure, and the resin portion of the negative electrode terminal electrode with the resin portion is formed. It is bonded to the metal plate of the metal plate with the resin part. By performing the third step while reducing the pressure in this way, the pressure in the surplus space formed by the metal plate, the negative electrode terminal electrode, and the resin portion becomes lower than the atmospheric pressure. As a result, the air containing water, which is a factor that accelerates the alkaline creep phenomenon, is removed in the surplus space, so that the amount of water in the surplus space is reduced. Therefore, since the electrolytic solution is prevented from seeping into the excess space from between the electrode plate of the negative electrode terminal electrode and the resin portion, it is possible to prevent the electrolytic solution from seeping out of the power storage module due to the alkaline creep phenomenon.

In the third step, after bonding except for a part of the resin portion, a part may be bonded while reducing the pressure in the space between the electrode plate and the metal plate of the negative electrode terminal electrode. According to this configuration, the pressure is reduced in a state where only a part of the resin portion is not bonded to the metal plate, so that the space between the metal plate and the negative electrode terminal electrode can be easily reduced in pressure.

In the third step, the negative electrode terminal electrode with the resin portion and the metal plate with the resin portion may be dried before joining a part of the resin portion. According to this configuration, since the third step is performed in a state where the metal plate, the negative electrode terminal electrode, and the resin portion are dried, the amount of water contained in the surplus space can be further reduced. Therefore, it is possible to more effectively suppress the electrolytic solution from seeping out of the power storage module due to the alkaline creep phenomenon.

A sealing portion for connecting resin portions is formed so as to surround the side surface of an electrode laminate composed of a plurality of bipolar electrodes, a negative electrode terminal electrode, and a metal plate, and an airtight internal space is created between adjacent electrodes. A fourth step of forming may be further provided, and the internal pressure of the surplus space may be lower than the internal pressure of the internal space. By making the internal pressure of the excess space lower than the internal pressure of the internal space in this way, the amount of water in the excess space is reduced, and the electrolytic solution is introduced from between the electrode plate of the negative electrode terminal electrode and the resin portion into the excess space. It is possible to suppress the exudation to the surface more effectively.

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 electrode laminate has a metal plate arranged outside in the stacking direction with respect to the electrode plate of the negative electrode terminal electrode, and has an extra space surrounded by the sealed body, the electrode plate of the negative electrode terminal electrode, and the metal plate. However, the internal pressure of the surplus space is lower than the atmospheric pressure.

The electrode laminate of this power storage module has a metal plate arranged outside in the stacking direction with respect to the electrode plate of the negative electrode terminal electrode, and is surrounded by the encapsulant, the electrode plate of the negative electrode terminal electrode, and the metal plate. It has a surplus space, and the internal pressure of the surplus space is lower than the atmospheric pressure. As described above, the excess space located in the vicinity of the negative electrode terminal electrode is depressurized, so that the amount of water that is a factor for accelerating the alkaline creep phenomenon is reduced in the excess space. As a result, it is possible to prevent the electrolytic solution in the internal space from seeping out into the excess space from between the electrode plate of the negative electrode terminal electrode and the sealing body. Therefore, it is possible to prevent the electrolytic solution from seeping out of the power storage module due to the alkaline creep phenomenon.

The internal pressure of the surplus space may be lower than the internal pressure of the internal space. As described above, since the internal pressure of the excess space is lower than the internal pressure of the internal space, it is possible to more effectively suppress the electrolytic solution from seeping into the excess space from between the electrode plate of the negative electrode terminal electrode and the sealing body. ..

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a power storage module and a method for manufacturing 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 for demonstrating the manufacturing method of the power storage module of FIG. It is a figure for demonstrating the manufacturing method of the power storage module of FIG. It is a figure for demonstrating the manufacturing method of the power storage module of FIG. It is a figure for demonstrating the manufacturing method of the power storage module of FIG.

Hereinafter, a preferred embodiment of the power storage module according to one aspect of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a power storage device. The power storage device 1 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage device 1 includes a module stack 2 including a plurality of stacked power storage modules 4, and a restraint member 3 that applies a restraining load to the module stack 2 in the stacking direction 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 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 not only functions as a connecting member for electrically connecting the power storage modules 4 to each other, but also serves as a heat sink 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 and united 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 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 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 has a second sealing portion 22 (sealing portion) 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.

Here, 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. 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, the first sealing portion 21, the electrode plate 15 of the negative electrode terminal electrode 18, and the metal plate 20 form a surplus space VA in which the electrolytic solution is not accommodated. 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. The inside of the surplus space VA is decompressed, and its internal pressure is lower than the atmospheric pressure. Further, the internal pressure of the surplus space VA is lower than the internal pressure of the internal space V in which the electrolytic solution is housed. As an example, the internal pressure of the surplus space VA can be 0 Pa or more and less than 0.1 MPa, and the internal pressure of the internal space V can be 0.1 MPa or more and 1 MPa or less. In the present embodiment, the internal pressure of the internal space V is about atmospheric pressure in a state where the internal gas is not generated.

Next, a method of manufacturing the power storage module 4 will be described with reference to FIGS. 4 to 7. First, a plurality of bipolar electrodes 14, a negative electrode termination electrode 18, a positive electrode termination electrode 19, and a metal plate 20 are prepared. Next, as shown in FIG. 4, the first edge portion 15c of the electrode plate 15 of the bipolar electrode 14, the edge portion 15c of the electrode plate 15 of the negative electrode terminal electrode 18, and the edge portion 20c of the metal plate 20 are first. The sealing portion 21 is coupled (first step). At this time, the first sealing portion 21 is coupled to one surface 15a of the electrode plate 15 of each electrode and one surface 20a of the metal plate 20. In the first step, the first sealing portion 21 is also coupled to the edge portion 15c of the electrode plate 15 of the positive electrode terminal electrode 19, but the positive electrode terminal electrode 19 is omitted in FIG. Examples of the method for connecting the first sealing portion 21 to the electrode plate 15 and the metal plate 20 of each electrode include welding by ultrasonic waves or heat.

Next, as shown in FIG. 5, a plurality of bipolar electrodes 14 (bipolar electrodes with a resin portion) to which the first sealing portion 21 is bonded are laminated, and a negative electrode terminal electrode to which the first sealing portion 21 is bonded is laminated. 18 (negative electrode with a resin portion) and a metal plate 20 (metal plate with a resin portion) to which the first sealing portion 21 is bonded are laminated (second step). By this step, a laminated body of a plurality of bipolar electrodes 14 is formed.

Next, as shown in FIG. 6, the first sealing portion 21 coupled to the negative electrode termination electrode 18 and the metal plate 20 to which the first sealing portion 21 is coupled are coupled to form the negative electrode termination electrode 18. A surplus space VA is formed between the electrode plate 15 and the metal plate 20 by the first sealing portion 21 (third step). More specifically, the first sealing portion 21 coupled to the one surface 15a of the electrode plate 15 of the negative electrode terminal electrode 18 is coupled to the other surface 20b of the metal plate 20 to which the first sealing portion 21 is not bonded. do.

In the third step, the first sealing portion 21 coupled to the negative electrode termination electrode 18 and the metal plate 20 while reducing the space between the electrode plate 15 and the metal plate 20 of the negative electrode termination electrode 18 from the atmospheric pressure. To combine with. More specifically, as shown in FIG. 7, after coupling except for a part of the first sealing portion 21, the space between the electrode plate 15 and the metal plate 20 of the negative electrode terminal electrode 18 is depressurized. While joining the rest. In the present embodiment, first, among the four edge portions 21a, 21b, 21c, 21d of the rectangular frame-shaped first sealing portion 21, the metal plate 20 and the first sealing are performed on the three edge portions 21a, 21b, 21c. It is combined with the part 21. After that, while reducing the space between the remaining unbonded edge portion 21d and the metal plate 20 and the space between the electrode plate 15 and the metal plate 20 of the negative electrode termination electrode 18, the first seal is formed at the edge portion 21d. The stop portion 21 and the metal plate 20 are connected. For the coupling between the first sealing portion 21 and the metal plate 20 at the edge portion 21d, for example, a device such as a vacuum sealer (not shown) can be used. In this case, the space between the electrode plate 15 and the metal plate 20 of the negative electrode terminal electrode 18 is evacuated with the uncoupled edge portion 21d side inserted into the suction portion of the vacuum sealer. Then, after the degree of vacuum in the space reaches a predetermined value, the first sealing portion 21 and the metal plate 20 are heated and pressed at the edge portion 21d to weld the first sealing portion 21 and the metal plate 20. do. As a result, the contact portion C of the metal plate 20 and the electrode plate 15 of the negative electrode terminal 18 are in contact with each other, and the metal plate 20 and the negative electrode terminal 18 are electrically connected.

Further, in the third step of the manufacturing method of the power storage module 4, before the edge portion 21d of the first sealing portion 21 is coupled to the metal plate 20, the negative electrode terminal electrode 18 to which the first sealing portion 21 is bonded is connected. , A drying step of drying the metal plate 20 to which the first sealing portion 21 is bonded is performed. As a result, the water adhering to the negative electrode terminal electrode 18, the metal plate 20, and the first sealing portion 21 is removed, and the water contained in the space between the electrode plate 15 and the metal plate 20 of the negative electrode terminal 18 is further reduced. Can be reduced. For example, a drying furnace or the like may be used for drying the negative electrode terminal electrode 18, the metal plate 20, and the first sealing portion 21. As an example, the drying temperature can be 100 ° C. or higher and 150 ° C. or lower, and the drying time can be 1 hour or longer and 24 hours or lower. In the present embodiment, the drying step is performed immediately before the edge portion 21d of the first sealing portion 21 is bonded to the metal plate 20 (that is, in the middle of the third step), but the drying step is performed more than in the third step. A drying step may be performed before. Further, from the viewpoint of removing water more effectively, it is desirable that the drying step be performed in a vacuum (0.1 MPa or less) environment.

Next, the plurality of laminated bipolar electrodes 14, the coupled negative electrode termination electrode 18 and the metal plate 20 are arranged in an injection molding die (not shown), and injection molding is performed to perform the first sealing. The second sealing portion 22 is formed so as to surround the stop portion 21. As a result, the sealing body 12 is formed on the side surface 11a of the electrode laminated body 11, and the internal space V is formed by the adjacent electrodes and the sealing body 12. In the step of forming the second sealing portion 22, vacuum drawing is not performed using a vacuum sealer or the like as in the third step described above, so that the internal pressure of the internal space V is, for example, about atmospheric pressure. Therefore, the internal pressure of the surplus space VA is lower than the internal pressure of the internal space V. After that, the electrolytic solution is injected into the internal space V between the bipolar electrodes 14 and 14. As a result, the power storage module 4 is obtained.

As described above, in the method of manufacturing the power storage module 4, the first sealing portion 21 in the negative electrode terminal 18 with the first sealing portion 21 and the metal plate 20 of the metal plate 20 with the first sealing portion 21 are provided. It has a third step of coupling and forming a surplus space VA by the first sealing portion 21 between the electrode plate 15 of the negative electrode terminal 18 and the metal plate 20, and in the third step, the negative electrode terminal 18 is formed. The space between the electrode plate 15 and the metal plate 20 is depressurized from the atmospheric pressure, and the first sealing portion 21 in the negative electrode terminal electrode 18 with the first sealing portion 21 and the metal plate with the first sealing portion 21 are provided. 20 is bonded to the metal plate 20.

Generally, in the power storage module, 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 the electrode plate 15 and the first sealing portion 21 in the coupling region K It may seep out of the power storage module through the gap between the two. On the other hand, it is formed by the metal plate 20, the negative electrode terminal electrode 18, and the first sealing portion 21 by performing the third step while reducing the pressure as in the manufacturing method of the power storage module 4 according to the present embodiment. The pressure in the surplus space VA becomes lower than the atmospheric pressure. As a result, the air containing water, which is a factor that accelerates the alkaline creep phenomenon, is removed in the surplus space VA, so that the amount of water in the surplus space is reduced. Therefore, it is suppressed that the electrolytic solution seeps into the excess space VA from between the electrode plate 15 of the negative electrode terminal 18 and the first sealing portion 21, and the electrolytic solution is discharged to the outside of the power storage module 4 due to the alkaline creep phenomenon. It is possible to suppress the exudation.

Further, since the pressure in the space between the electrode plate 15 and the metal plate 20 of the negative electrode terminal electrode 18 is lower than the atmospheric pressure by performing the third step while reducing the pressure, the metal plate 20 at the contact portion C. And the electrode plate 15 of the negative electrode terminal electrode 18 are in contact with each other more reliably. Therefore, it is possible to reduce the contact resistance between the metal plate 20 and the negative electrode terminal electrode 18.

Further, in the third step, after bonding except for a part (edge portion 21d) of the first sealing portion 21, the space between the electrode plate 15 and the metal plate 20 of the negative electrode terminal electrode 18 is depressurized. A part (edge 21d) is joined. As a result, the pressure is reduced in a state where only a part of the first sealing portion is not bonded to the metal plate 20, so that the space between the metal plate 20 and the negative electrode terminal electrode 18 can be easily reduced in pressure. ..

Further, in the third step of the manufacturing method of the power storage module 4, the negative electrode terminal 18 with the first sealing portion 21 and the first sealing are first sealed before the part (edge portion 21d) of the first sealing portion 21 is coupled. The metal plate 20 with the stopper 21 is dried. As a result, since the third step is performed in a state where the metal plate 20, the negative electrode terminal electrode 18, and the first sealing portion 21 are dried, the amount of water contained in the surplus space VA can be further reduced. Therefore, it is possible to more effectively suppress the electrolytic solution from seeping out of the power storage module 4 due to the alkaline creep phenomenon.

Further, a fourth step of forming a second sealing portion 22 for connecting the first sealing portions 21 to each other so as to surround the side surface 11a of the electrode laminate 11 and forming an airtight internal space V between adjacent electrodes. Further, the internal pressure of the surplus space VA is made lower than the internal pressure of the internal space V. By lowering the internal pressure of the excess space VA to be lower than the internal pressure of the internal space V in this way, the amount of water in the excess space VA is reduced, and the electrolytic solution is first sealed with the electrode plate 15 of the negative electrode termination electrode 18. It is possible to more effectively suppress the exudation into the surplus space VA from between the portions 21.

The electrode laminate of the power storage module 4 has a metal plate 20 arranged outside the stacking direction D with respect to the electrode plate 15 of the negative electrode termination electrode 18, and also has a sealing body 12 and an electrode plate 15 of the negative electrode termination electrode 18. It has a surplus space VA surrounded by the metal plate 20 and the metal plate 20, and the internal pressure of the surplus space VA is lower than the atmospheric pressure. As described above, the excess space VA located in the vicinity of the negative electrode terminal electrode 18 is depressurized, so that the amount of water that is a factor that accelerates the alkaline creep phenomenon is reduced in the excess space VA. As a result, the electrolytic solution in the internal space V is prevented from seeping out into the excess space VA from between the metal plate 20 of the negative electrode terminal 18 and the sealing body 12. Therefore, it is possible to prevent the electrolytic solution from seeping out of the power storage module 4 due to the alkaline creep phenomenon.

Further, since the excess space VA is depressurized, the metal plate 20 and the electrode plate 15 of the negative electrode terminal electrode 18 are more reliably in contact with each other at the contact portion C. Therefore, it is possible to reduce the contact resistance between the metal plate 20 and the negative electrode terminal electrode 18.

Further, the internal pressure of the surplus space VA is lower than the internal pressure of the internal space V. As described above, since the internal pressure of the excess space VA is lower than the internal pressure of the internal space V, the electrolytic solution exudes into the excess space VA from between the electrode plate 15 of the negative electrode terminal 18 and the sealing body 12. It can be suppressed more effectively.

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, in the third step, after bonding except for a part (edge portion 21d) of the first sealing portion 21, between the electrode plate 15 of the negative electrode terminal electrode 18 and the metal plate 20. An example of connecting a part (edge portion 21d) while reducing the pressure in the space of the above has been described. For example, the first sealing portion 21 coupled to the negative electrode terminal electrode 18 in a vacuum vessel and the metal plate 20 are connected at once. May be combined.

Further, in the above embodiment, an example in which the negative electrode terminal 18 with the first sealing portion 21 and the metal plate 20 with the first sealing portion 21 are dried in the middle of the third step has been described. It is not necessary to dry the negative electrode terminal 18 with the stop portion 21 and the metal plate 20 with the first sealing portion 21.

Further, in the above embodiment, an example in which the internal pressure of the surplus space VA is made lower than the internal pressure of the internal space V has been described, but the internal pressure of the surplus space VA does not have to be lower than the internal pressure of the internal space V.

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 ... Encapsulant, 13 ... Separator, 14 ... Bipolar electrode, 15 ... Electrode plate, 15a ... One side, 15b ... The other side, 15c ... Edge, 18 ... Negative electrode terminal electrode, 20 ... Metal plate, 21 ... First sealing part (resin part), 22 ... Second sealing part (sealing part), D ... Laminating direction, V ... Internal space, VA ... Surplus space ..

Claims (6)

The first step of bonding the resin portion to the edge portion of the electrode plate of the bipolar electrode, the edge portion of the electrode plate of the negative electrode terminal electrode, and the edge portion of the metal plate, respectively.
A second step of laminating a plurality of the bipolar electrodes with the resin portion and laminating the negative electrode terminal electrode with the resin portion and the metal plate with the resin portion.
The resin portion of the negative electrode terminal electrode with the resin portion and the metal plate of the metal plate with the resin portion are coupled to each other, and a surplus due to the resin portion is provided between the electrode plate of the negative electrode terminal electrode and the metal plate. It has a third step of forming a space,
In the third step, the resin portion of the negative electrode terminal electrode with the resin portion and the resin portion with the resin portion are attached while the space between the electrode plate of the negative electrode terminal electrode and the metal plate is depressurized from atmospheric pressure. A method for manufacturing a power storage module, which combines a metal plate with the metal plate. In the third step, after removing a part of the resin portion and binding the resin portion, the part of the resin portion is bonded while reducing the pressure in the space between the electrode plate of the negative electrode terminal electrode and the metal plate. The method for manufacturing a power storage module according to. The power storage module according to claim 2, wherein in the third step, the negative electrode terminal electrode with the resin portion and the metal plate with the resin portion are dried before the part of the resin portion is bonded. Production method. A sealing portion for connecting the resin portions is formed so as to surround the side surface of the electrode laminate composed of the plurality of the bipolar electrodes, the negative electrode termination electrode, and the metal plate, and the adjacent electrodes are airtight. Further equipped with a fourth step of forming the internal space of the
The method for manufacturing a power storage module according to any one of claims 1 to 3, wherein the internal pressure of the surplus space is made lower than the internal pressure of the internal space. 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 in the stacking direction of the laminated body.
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, and is surrounded by the encapsulant, the electrode plate of the negative electrode terminal electrode, and the metal plate. Has extra space
A power storage module in which the internal pressure of the surplus space is lower than the atmospheric pressure. The power storage module according to claim 5, wherein the internal pressure of the surplus space is lower than the internal pressure of the internal space.

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