JP2020095909A - Manufacturing method of power storage module and power storage module - Google Patents

Abstract

To provide a manufacturing method of power storage module capable of improving reliability and productivity.SOLUTION: A manufacturing method of a power storage module 4 includes a first welding step of welding a resin frame 21, placed on the first face 15a of the electrode plate 15 of a bipolar electrode 14, while compressing by compression members 81, 82, a second welding step of welding a pair of resin frames 22, 22, placed to sandwich the electrode plate 15 of a negative electrode termination electrode 18, while compressing by the compression members 81, 82, and a third welding step of welding a pair of resin frames 23, 23, placed to sandwich the electrode plate 15 of a positive electrode termination electrode 19, while compressing by the compression members 81, 82. Total of the thickness of the electrode plate 15 of the bipolar electrode 14 and the thickness of resin frame 21, total of the thickness of the electrode plate 15 of the negative electrode termination electrode 18 and the thickness of the pair of resin frames 22, 22, and the total of the thickness of the electrode plate 15 of the positive electrode termination electrode 19 are all the same.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method of manufacturing a power storage module and a power storage module.

As a conventional power storage module, a plurality of bipolar electrodes formed of electrode plates each having a positive electrode layer and a negative electrode layer formed on both sides, a negative electrode termination electrode formed of an electrode plate formed of a negative electrode layer, and an electrode formed of a positive electrode layer. A bipolar battery including a positive terminal electrode made of a plate is known (see Patent Document 1). Such an electricity storage module includes a bipolar electrode unit in which a sealing body is integrally provided with a bipolar electrode, the sealing body being provided on the peripheral portion of one surface of the electrode plate of the bipolar electrode, and one surface of the electrode plate of the negative terminal electrode. A negative electrode terminal electrode unit in which a sealing body provided on the peripheral portion of the positive electrode terminal electrode is integrally formed with a negative electrode terminal electrode, and a sealing body provided on the peripheral portion of one surface of the electrode plate of the positive electrode terminal electrode is a positive electrode termination electrode. It is conceivable that each of the positive electrode and the terminal electrode unit integrally configured with is manufactured and then assembled by stacking them. The space between adjacent electrodes is sealed by a sealing body, and the electrolytic solution is contained in the internal space formed between the electrodes.

JP, 2011-204386, A

In the electricity storage module as described above, when the electrolytic solution is an alkaline solution, the electrolytic solution propagates on the surface of the electrode plate of the negative terminal electrode by a so-called alkaline creep phenomenon and passes between the sealing body and the electrode plate. It may exude to the outer surface side of the electrode plate. If the electrolytic solution leaks to the outer surface side and diffuses, for example, corrosion of a conductive plate disposed adjacent to the outside of the negative electrode termination electrode, short circuit between the negative electrode termination electrode and the restraining member, or the like may occur. Is not preferable from the viewpoint of.

Therefore, for example, an uncoated metal plate is provided on the outside of the negative electrode termination electrode, and sealing is performed between the negative electrode termination electrode and the uncoated metal plate and on the opposite side of the uncoated metal plate from the negative electrode termination electrode. It is conceivable to form a surplus space between the negative terminal electrode and the uncoated metal plate by welding the body to suppress the progress of alkali creep due to the influence of humidity in the external space. Even when such an uncoated metal plate is provided, it is conceivable to form a negative electrode termination electrode unit in which the sealing body and the uncoated metal plate are integrally formed with the negative electrode termination electrode.

Further, in the bipolar electrode of the storage module as described above, for example, when the internal pressure of the internal space rises, the load due to the internal pressure of the internal space adjacent in one direction is canceled, but the positive electrode termination located at the end of the storage module. The electrode does not cancel the load due to the internal pressure of the internal space. Therefore, when the internal pressure rises, the positive electrode termination electrode may be deformed, which may cause electrolyte leakage and damage on the positive electrode termination electrode unit side, which is not preferable from the viewpoint of reliability.

Therefore, it is conceivable to suppress the deformation of the positive electrode termination electrode by welding the sealing bodies to both surfaces of the electrode plate of the positive electrode termination electrode. Even in such a case, it is conceivable to form a positive electrode termination electrode unit in which the sealing body is integrally configured with the positive electrode termination electrode.

In the case as described above, for example, the total of the thickness of the electrode plate of the negative electrode termination electrode, the thickness of the uncoated metal plate and the thickness of the sealing body, and the thickness of the electrode plate of the positive electrode termination electrode and the thickness of the sealing body. The total may be different from the total of the thickness of the electrode plate of the bipolar electrode and the thickness of the sealing body. Therefore, for example, when each unit is formed by welding the sealing body while applying pressure with a pair of pressure members having a predetermined clearance, the clearance between the pair of pressure members can be adjusted for each unit. You may be asked. Therefore, the productivity of the power storage module may decrease.

An object of the present invention is to provide a method of manufacturing an electricity storage module and an electricity storage module that can improve reliability and productivity.

The method for manufacturing an electricity storage module according to the present invention is a positive electrode active material coated on one surface, a bipolar electrode made of a metal plate coated with a negative electrode active material on the other surface opposite to one surface, And a first preparing step of preparing at least one frame-shaped resin member, and a resin arranged in at least one of the peripheral portions of one surface and the other surface of the metal plate of the bipolar electrode and prepared in the first preparing step. A first welding step of forming a bipolar electrode unit by welding a member while applying pressure with a pair of pressure members; a negative electrode terminal electrode made of a metal plate having one surface coated with a negative electrode active material; A second preparation step of preparing a frame-shaped resin member and a pair of resin members arranged so as to sandwich the peripheral edge portion of the metal plate of the negative terminal electrode from the thickness direction and prepared in the second preparation step. Second welding step of forming a negative electrode terminal electrode unit by applying pressure with a pressure member, a positive electrode terminal electrode made of a metal plate having one surface coated with a positive electrode active material, and a pair of frame-shaped resin members And a pair of resin members arranged in such a manner that the peripheral portion of the metal plate of the positive electrode termination electrode is sandwiched from the thickness direction and prepared in the third preparing step by a pair of pressure members. The third welding step of forming the positive electrode terminal electrode unit by welding while stacking the bipolar electrode units along one direction, and the negative electrode terminal electrode at one end in one direction of the bipolar electrode unit group including a plurality of bipolar electrode units. The negative electrode terminal electrode unit is arranged so that the negative electrode active material faces the bipolar electrode unit group, and the positive electrode active material of the positive electrode terminal electrode faces the bipolar electrode unit group at the other end in one direction of the bipolar electrode unit group. Stacking step of arranging the positive electrode terminal electrode unit, the total thickness of the metal plate and the resin member of the bipolar electrode prepared in the first preparation step, and the negative electrode prepared in the second preparation step. The total thickness of the metal plate of the terminal electrode and the thickness of the pair of resin members, and the total thickness of the metal plate of the positive electrode termination electrode and the thickness of the pair of resin members prepared in the third preparation step are all the same. In the second welding step, a space surrounded by the metal plate of the negative terminal electrode and the pair of resin members is formed.

In the method for manufacturing the electricity storage module, in the second welding step, a space surrounded by the metal plate of the negative terminal electrode and the pair of resin members is formed on a path that can be a path for moving the electrolytic solution. Therefore, it is possible to prevent the moisture contained in the outside air from entering the gap between the negative terminal electrode and the metal plate, which is the starting point of the electrolyte oozing out due to the alkaline creep phenomenon. Accordingly, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and to prevent the electrolytic solution from seeping out of the power storage module. Further, in this method for manufacturing an electricity storage module, in the third welding step, the positive electrode terminal electrode unit is welded with the resin member on both one surface and the other surface of the metal plate. Therefore, when the internal pressure of the internal space rises, the positive electrode terminal electrode is less likely to be deformed, as compared with the case where the resin member is welded to only one surface or the other surface of the metal plate, for example. As a result, it is possible to suppress the leakage and damage of the electrolytic solution on the positive electrode terminal electrode unit side. As a result, the reliability of the power storage module formed by the method for manufacturing the power storage module can be improved. Further, the total thickness of each member prepared in each of the first preparation step, the second preparation step, and the third preparation step is the same. Therefore, once the clearance between the pair of pressure members is adjusted, the clearance between the pair of pressure members can be adjusted in each of the first welding step, the second welding step, and the third welding step. It becomes unnecessary. Thereby, the productivity of the power storage module can be improved.

A method of manufacturing an electricity storage module according to the present invention includes an uncoated metal plate on which an active material is not coated, a fourth preparation step of preparing a pair of frame-shaped resin members, and an uncoated metal plate. A fourth welding step of forming a metal plate unit by welding while sandwiching the peripheral portion from the thickness direction and pressing the pair of resin members prepared in the fourth preparing step with a pair of pressurizing members; Further including the total thickness of the metal plate and the resin member of the bipolar electrode prepared in the first preparation step, and the thickness of the metal plate of the negative terminal electrode and the pair of resin members prepared in the second preparation step. The total thickness, the total thickness of the metal plate of the positive electrode terminal electrode prepared in the third preparation step and the total thickness of the pair of resin members, and the thickness and the pair of uncoated metal plates prepared in the fourth preparation step. And the total thickness of the resin members are all the same, and in the laminating step, the metal plate unit is arranged so as to face the other surface of the metal plate of the negative terminal electrode on which the negative electrode active material is not coated. Good.

In this case, in the stacking step, by arranging the metal plate unit so as to face the metal plate of the negative terminal electrode, an extra space is formed on the path that can serve as the electrolyte migration path. Therefore, it is possible to prevent the moisture contained in the outside air from entering the gap between the negative terminal electrode and the metal plate, which is the starting point of the electrolyte oozing out due to the alkaline creep phenomenon. Accordingly, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and to prevent the electrolytic solution from seeping out of the power storage module. Therefore, the reliability of the power storage module formed by the method for manufacturing the power storage module can be improved. In addition, the total thickness of each member prepared in each of the first preparation step, the second preparation step, the third preparation step, and the fourth preparation step is the same. For this reason, once the clearance between the pair of pressure members is adjusted, the clearance between the pair of pressure members in each of the first welding step, the second welding step, the third welding step, and the fourth welding step. Need not be adjusted. Thereby, the productivity of the power storage module can be improved.

In the method for manufacturing the electricity storage module according to the present invention, the pair of resin members are prepared in the first preparation step, and the first welding step is arranged so as to sandwich the peripheral portion of the metal plate of the bipolar electrode from the thickness direction. The pair of resin members prepared in the one preparation step may be welded while being pressed by the pair of pressing members. In this case, the thickness of each resin member can be made the same if necessary. As a result, common parts can be achieved.

In the method for manufacturing the electricity storage module according to the present invention, the thickness of each resin member in the pair of resin members prepared in the first preparation step and the thickness of each resin member in the pair of resin members prepared in the second preparation step are described. The thickness and the thickness of each resin member in the pair of resin members prepared in the third preparation step may all be the same. In this case, the parts can be made common by making the thicknesses of the respective resin members the same.

In the method of manufacturing an electricity storage module according to the present invention, the thickness of the metal plate of the bipolar electrode prepared in the first preparation step, the thickness of the metal plate of the negative electrode terminal electrode prepared in the second preparation step, and the third preparation step. The thickness of the metal plate of the positive electrode termination electrode prepared in 1 may be all the same. In this case, parts can be made common by making the thicknesses of the metal plates the same.

The electricity storage module according to the present invention includes a bipolar electrode formed of a metal plate having one surface coated with a positive electrode active material and the other surface opposite to the one surface coated with a negative electrode active material, and a bipolar electrode. Of the metal plate, a bipolar electrode unit having a frame-shaped resin member that is welded to at least one of the peripheral portions of the one surface and the other surface of the metal plate, and a negative electrode formed of a metal plate having one surface coated with a negative electrode active material. A negative electrode terminal electrode unit having a pair of frame-shaped resin members that are welded so as to be sandwiched between the terminal electrode and the negative terminal electrode on one side and the other side of the metal plate from the thickness direction, and on one side. A positive electrode terminal electrode made of a metal plate coated with a positive electrode active material, and a pair of frame-shaped resins welded to the peripheral portions of one surface and the other surface of the metal plate of the positive electrode terminal electrode so as to be sandwiched in the thickness direction. A negative electrode terminal electrode unit having a member, wherein the negative electrode terminal electrode unit has a negative electrode active electrode of the negative electrode terminal electrode at one end in one direction of a bipolar electrode unit group consisting of a plurality of bipolar electrode units stacked along one direction. The material is arranged so as to face the bipolar electrode unit group, and the positive electrode termination electrode unit is arranged so that the positive electrode active material of the positive electrode termination electrode faces the bipolar electrode unit group at the other end in one direction of the bipolar electrode unit group. The total thickness of the metal plate of the bipolar electrode and the resin member of the bipolar electrode unit, the total thickness of the metal plate of the negative terminal electrode and the thickness of the pair of resin members of the negative terminal electrode unit, and the positive terminal electrode. The thickness of the metal plate and the total thickness of the pair of resin members of the positive electrode termination electrode unit are all the same, and a space surrounded by the metal plate of the negative electrode termination electrode and the pair of resin members of the negative electrode termination electrode unit is formed. An electrolytic solution containing an alkaline solution is contained in the internal space formed by the metal plate of the bipolar electrode, the metal plate of the negative terminal electrode, and the resin member of the bipolar electrode unit.

In this electricity storage module, a space surrounded by the metal plate of the negative terminal electrode and the pair of resin members is formed on a path that can serve as a movement path of the electrolytic solution. Therefore, it is possible to prevent the moisture contained in the outside air from entering the gap between the negative terminal electrode and the metal plate, which is the starting point of the electrolyte oozing out due to the alkaline creep phenomenon. Accordingly, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and to prevent the electrolytic solution from seeping out of the power storage module. Further, in this electricity storage module, the positive electrode terminal electrode unit has the resin member welded to both one surface and the other surface of the metal plate. Therefore, when the internal pressure of the internal space rises, the positive electrode terminal electrode is less likely to be deformed, as compared with the case where the resin member is welded to only one surface or the other surface of the metal plate, for example. As a result, it is possible to suppress the leakage and damage of the electrolytic solution on the positive electrode terminal electrode unit side. As a result, the reliability of the power storage module can be improved. Further, the total thickness of each member of the bipolar electrode unit, the total thickness of each member of the negative electrode termination electrode unit, and the total thickness of each member of the positive electrode termination electrode unit are all the same. Therefore, for example, when the resin member is welded to the metal plate of the bipolar electrode while being pressed by the pair of pressure members, when the resin member is welded to the metal plate of the negative terminal electrode while being pressed by the pair of pressure members. When the resin member is welded to the metal plate of the positive electrode terminal electrode while applying pressure by the pair of pressure members, once the clearance between the pair of pressure members is adjusted, It is no longer necessary to adjust the clearance. Thereby, the productivity of the power storage module can be improved.

The electricity storage module according to the present invention is arranged such that the negative electrode active material in the metal plate of the negative terminal electrode is opposed to the other surface that is not coated, and the active material is an uncoated metal plate that is not coated, And further comprising a metal plate unit having a pair of frame-shaped resin members welded so as to be sandwiched in the peripheral direction on one surface and the other surface of the uncoated metal plate from the thickness direction, the metal plate of the bipolar electrode Thickness and the total thickness of the resin member of the bipolar electrode unit, the total thickness of the metal plate of the negative terminal electrode and the thickness of the pair of resin members of the negative terminal electrode unit, the thickness of the metal plate of the positive terminal electrode and the positive terminal electrode The total thickness of the pair of resin members of the unit, the total thickness of the uncoated metal plate, and the total thickness of the pair of resin members of the metal plate unit may be the same.

In this case, by disposing the metal plate unit so as to face the metal plate of the negative terminal electrode, an extra space is formed on a path that can be a path for moving the electrolytic solution. Therefore, it is possible to prevent the moisture contained in the outside air from entering the gap between the negative terminal electrode and the metal plate, which is the starting point of the electrolyte oozing out due to the alkaline creep phenomenon. Accordingly, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and to prevent the electrolytic solution from seeping out of the power storage module. Therefore, the reliability of the power storage module can be improved. The total thickness of each member of the bipolar electrode unit, the total thickness of each member of the negative terminal electrode unit, the total thickness of each member of the positive terminal electrode unit, and the total thickness of each member of the metal plate unit. And are all the same. Therefore, for example, when the resin member is welded to the metal plate of the bipolar electrode while being pressed by the pair of pressure members, when the resin member is welded to the metal plate of the negative terminal electrode while being pressed by the pair of pressure members. When the resin member is welded to the metal plate of the positive electrode terminal electrode while being pressed by the pair of pressure members, and when the resin member is welded to the uncoated metal plate while being pressed by the pair of pressure members. Moreover, once the clearance between the pair of pressure members is adjusted, it is not necessary to adjust the clearance between the pair of pressure members. Thereby, the productivity of the power storage module can be improved.

In the electricity storage module according to the present invention, the bipolar electrode unit may have a pair of resin members welded to the peripheral portions of the one surface and the other surface of the metal plate of the bipolar electrode so as to be sandwiched in the thickness direction. .. In this case, the thickness of each resin member can be made the same if necessary. As a result, common parts can be achieved.

In the electricity storage module according to the present invention, the thickness of each resin member in the pair of resin members included in the bipolar electrode unit, the thickness of each resin member in the pair of resin members included in the negative electrode terminal electrode unit, and the positive electrode terminal electrode unit are The thickness of each resin member in the pair of resin members may be the same. In this case, the parts can be made common by making the thicknesses of the respective resin members the same.

In the electricity storage module according to the present invention, the metal plate of the bipolar electrode, the metal plate of the negative terminal electrode, and the metal plate of the positive terminal electrode may all have the same thickness. In this case, parts can be made common by making the thicknesses of the metal plates the same.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of an electrical storage module and electrical storage module which can make reliability and productivity can be provided.

FIG. 1 is a schematic cross-sectional view showing an embodiment of a power storage device. FIG. 2 is a schematic cross-sectional view showing the internal configuration of the electricity storage module shown in FIG. FIG. 3 is a cross-sectional view showing a bipolar electrode unit, a negative electrode termination electrode unit, and a positive electrode termination electrode unit of the electricity storage module of FIG. FIG. 4 is an enlarged cross-sectional view showing a part of the power storage module of FIG. 5: is a figure which shows the welding machine used with the manufacturing method of the electrical storage module of FIG. FIG. 6 is a flowchart showing a method of manufacturing the power storage module of FIG. FIG. 7 is a partially enlarged cross-sectional view of a power storage module according to a comparative example. FIG. 8 is a schematic cross-sectional view showing a modified example of the power storage module. 9 is a cross-sectional view showing a bipolar electrode unit, a negative electrode termination electrode unit, a positive electrode termination electrode unit, and a metal plate unit of the electricity storage module of FIG. FIG. 10 is a cross-sectional view showing a modified example of the bipolar electrode unit. FIG. 11: is sectional drawing which shows the modification of a bipolar electrode unit, a negative electrode termination electrode unit, and a positive electrode termination electrode unit.

Hereinafter, a power storage device including a power storage module according to an embodiment will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference symbols, without redundant description.

Power storage device 1 shown in FIG. 1 is used as a battery in various vehicles such as forklifts, hybrid vehicles, electric vehicles, and the like. 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 D1 of the module stack 2. ..

The module stack 2 includes a plurality (here, three) of power storage modules 4 and a plurality (here, four) of conductive plates 5. The power storage module 4 is a bipolar battery and has a rectangular shape when viewed from the stacking direction D1. The power storage module 4 is, for example, a nickel-hydrogen secondary battery, a secondary battery such as a lithium-ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-hydrogen secondary battery will be exemplified.

The electricity storage modules 4 and 4 that are adjacent to each other in the stacking direction D1 are electrically connected to each other via the conductive plate 5. The conductive plates 5 are arranged between the power storage modules 4 and 4 adjacent to each other in the stacking direction D1 and outside the power storage module 4 located at the stacking end. A positive electrode terminal 6 is connected to one of the conductive plates 5 arranged outside the power storage module 4 located at the stacking end. The negative electrode terminal 7 is connected to the other conductive plate 5 arranged outside the power storage module 4 located at the stacking end. The positive electrode terminal 6 and the negative electrode terminal 7 are drawn out, for example, from an edge portion of the conductive plate 5 in a direction intersecting the stacking direction D1. The positive electrode terminal 6 and the negative electrode terminal 7 charge and discharge the power storage module 4.

Inside the conductive plate 5, a plurality of flow paths 5a for circulating a refrigerant such as air are provided. The flow path 5a extends, for example, along a direction intersecting (orthogonal to) the stacking direction D1 and the pulling-out directions of the positive electrode terminal 6 and the negative electrode terminal 7, respectively. The conductive plate 5 has a function as a connecting member that electrically connects the power storage modules 4 to each other, and also functions as a heat dissipation plate that radiates the heat generated in 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 viewed from the stacking direction D1 is smaller than the area of the electricity storage module 4, but from the viewpoint of improving heat dissipation, the area of the electrically conductive plate 5 is equal to that of the electricity storage module 4. It may be the same as the area of the module 4, or may be larger than the area of the electricity storage module 4.

The restraint member 3 includes a pair of end plates 8 that sandwich the module stack 2 in the stacking direction D1, and fastening bolts 9 and nuts 10 that fasten the end plates 8 together. The end plate 8 is a rectangular metal plate having an area that is slightly larger than the areas of the power storage module 4 and the conductive plate 5 when viewed in the stacking direction D1. 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 the end plate 8 and the conductive plate 5 from each other.

The edge of the end plate 8 is provided with an insertion hole 8a at a position outside the module laminate 2. The fastening bolt 9 is passed from the insertion hole 8a of the one end plate 8 toward the insertion hole 8a of the other end plate 8, and the tip end portion of the fastening bolt 9 protruding from the insertion hole 8a of the other end plate 8 is The nut 10 is screwed. As a result, the power storage module 4 and the conductive plate 5 are sandwiched by the end plates 8 to be unitized as the module laminated body 2, and a restraining load is applied to the module laminated body 2 in the laminating direction D1.

Next, the configuration of the power storage module 4 will be described in detail. As shown in FIG. 2, the electricity storage module 4 includes an electrode stack 11 and a resin sealing body 12 that seals the electrode stack 11. The electrode stacked body 11 is configured by a plurality of units stacked along the stacking direction (one direction) D1 of the power storage module 4 via the separator 13. These units include a plurality of bipolar electrode units 31, one negative electrode termination electrode unit 32, and one positive electrode termination electrode unit 33.

As shown in FIGS. 2 to 4, the bipolar electrode unit 31 includes the bipolar electrode 14 and a resin frame (resin member) 21. The bipolar electrode 14 has a first surface (one surface of the electrode plate 15 of the bipolar electrode 14) 15a and a second surface opposite to the first surface 15a (the other surface of the electrode plate 15 of the bipolar electrode 14). It has an electrode plate (metal plate) 15 including 15b, a positive electrode 16 provided on the first surface 15a, and a negative electrode 17 provided on the second surface 15b. The positive electrode 16 is a positive electrode active material layer formed by applying the positive electrode active material to the electrode plate 15. The negative electrode 17 is a negative electrode active material layer formed by applying the negative electrode active material to the electrode plate 15. In the electrode stacked body 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of another bipolar electrode 14 that is adjacent in one of the stacking directions D1 with the separator 13 interposed therebetween. In the electrode stacked body 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 D1 with the separator 13 interposed therebetween.

The resin frame 21 is continuously provided over the entire circumference of the peripheral edge portion 15c on the first surface 15a of the electrode plate 15, and has a rectangular annular shape (frame shape) when viewed from the stacking direction D1. The resin frame 21 is welded to the first surface 15a of the electrode plate 15 by ultrasonic waves or heat (energy), for example, and is airtightly bonded. The resin frame 21 is, for example, a film having a predetermined thickness in the stacking direction D1. When viewed from the stacking direction D1, the inner edge of the resin frame 21 is located between the peripheral edge portions 15c of the electrode plates 15 adjacent to each other in the stacking direction D1. When viewed in the stacking direction D1, the outer edge of the resin frame 21 projects outward from the edge of the electrode plate 15, and the tip portion thereof is embedded in the sealing body 12. The plurality of bipolar electrode units 31 are stacked along the stacking direction D1 via the separator 13 to form a bipolar electrode unit group 30. The inner side means the center side of the electricity storage module 4 when viewed from the stacking direction D1. The outer side refers to the side away from the center of the electricity storage module 4 when viewed in the stacking direction D1.

The negative electrode termination electrode unit 32 includes the negative electrode termination electrode 18 and a pair of resin frames (resin members) 22 and 22. The negative terminal electrode 18 includes an electrode plate 15 and a negative electrode 17 provided on the second surface (one surface of the electrode plate 15 of the negative terminal electrode 18) 15b of the electrode plate 15. The negative electrode termination electrode 18 is arranged at one end of the bipolar electrode unit group 30 in the stacking direction D1 such that the negative electrode 17 of the negative electrode termination electrode 18 faces the bipolar electrode unit group 30. The negative electrode 17 provided on the second surface 15b of the electrode plate 15 of the negative terminal electrode 18 faces the positive electrode 16 of the bipolar electrode 14 at one end in the stacking direction D1 via the separator 13. No active material is applied to the first surface (the other surface of the electrode plate 15 of the negative electrode termination electrode 18) 15a of the electrode plate 15 of the negative electrode termination electrode 18.

The pair of resin frames 22 and 22 are continuously provided over the entire circumference of the peripheral edge portion 15c on the first surface 15a and the second surface 15b of the electrode plate 15 of the negative electrode termination electrode 18, respectively, and viewed from the stacking direction D1. It has a rectangular ring shape (frame shape). The pair of resin frames 22 and 22 are welded to each of the first surface 15a and the second surface 15b of the electrode plate 15 by, for example, ultrasonic waves or heat, and are airtightly joined. That is, the pair of resin frames 22 and 22 are welded to the peripheral edge portions 15c of the first surface 15a and the second surface 15b of the electrode plate 15 so as to sandwich the electrode plate 15 of the negative terminal electrode 18 from the thickness direction. There is. The resin frame 22 is, for example, a film having a predetermined thickness in the stacking direction D1. When viewed in the stacking direction D1, the inner edge of the resin frame 22 is located inside the edge of the electrode plate 15. When viewed in the stacking direction D1, the outer edge of the resin frame 21 projects outward from the edge of the electrode plate 15, and the tip portion thereof is embedded in the sealing body 12.

The positive electrode termination electrode unit 33 includes the positive electrode termination electrode 19 and a pair of resin frames (resin members) 23, 23. The positive electrode termination electrode 19 has an electrode plate 15 and a positive electrode 16 provided on the first surface (one surface of the electrode plate 15 of the positive electrode termination electrode 19) 15 a of the electrode plate 15. The positive electrode termination electrode 19 is arranged at the other end of the bipolar electrode unit group 30 in the stacking direction D1 so that the positive electrode 16 of the positive electrode termination electrode 19 faces the bipolar electrode unit group 30. The positive electrode 16 provided on the first surface 15a of the electrode plate 15 of the positive electrode termination electrode 19 faces the negative electrode 17 of the bipolar electrode 14 at the other end in the stacking direction D1 via the separator 13. No active material is applied to the second surface 15 b of the electrode plate 15 of the positive electrode termination electrode 19 (the other surface of the electrode plate 15 of the positive electrode termination electrode 19 ).

The pair of resin frames 23, 23 are continuously provided over the entire circumference of the peripheral edge portion 15c on the first surface 15a and the second surface 15b of the electrode plate 15, respectively, and have a rectangular annular shape (frame shape) when viewed from the stacking direction D1. ). The pair of resin frames 23, 23 are welded to each of the first surface 15a and the second surface 15b of the electrode plate 15 by, for example, ultrasonic waves or heat, and are airtightly joined. That is, the pair of resin frames 23, 23 are welded to the peripheral edge portions 15c of the first surface 15a and the second surface 15b of the electrode plate 15 so as to sandwich the electrode plate 15 of the positive electrode termination electrode 19 from the thickness direction. There is. The resin frame 23 is, for example, a film having a predetermined thickness in the stacking direction D1. When viewed from the stacking direction D1, the inner edge of the resin frame 23 is located inside the edge of the electrode plate 15. When viewed from the stacking direction D1, the outer edge of the resin frame 23 projects outward from the edge of the electrode plate 15, and the tip portion thereof is embedded in the sealing body 12. The resin frames 21, 22, 23 adjacent to each other along the stacking direction D1 may be separated from each other or may be in contact with each other.

The electrode plate 15 forming the bipolar electrode 14, the negative electrode termination electrode 18, and the positive electrode termination electrode 19 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 peripheral edge portion 15c of the electrode plate 15 has a rectangular frame shape and is an uncoated region where the positive electrode active material and the negative electrode active material are not coated. Examples of the positive electrode active material forming the positive electrode 16 include nickel hydroxide. Examples of the negative electrode active material forming the negative electrode 17 include a hydrogen storage alloy. In the present embodiment, the formation area of the negative electrode 17 on the second surface 15b of the electrode plate 15 is slightly larger than the formation area of the positive electrode 16 on the first surface 15a of the electrode plate 15.

The region of the electrode plate 15 forming the bipolar electrode 14 that is welded to the resin frame 21 (the region where the peripheral edge portion 15c of the first surface 15a and the resin frame 21 overlap) is roughened. The roughened region may be the overlapping region, but in the present embodiment, the entire first surface 15a of the electrode plate 15 (the entire surface from the peripheral edge portion 15c to the central portion) is roughened. Regions of the electrode plate 15 forming the negative electrode termination electrode 18 and the positive electrode termination electrode 19 that are welded to the resin frame 22 or the resin frame 23 (the peripheral portions 15c and the resin frame 22 or the resin on the first surface 15a and the second surface 15b). The area where the frame 23 overlaps) is roughened. The roughened region may be the overlapping region, but in the present embodiment, the entire first surface 15a and the second surface 15b of the electrode plate 15 (the entire surface from the peripheral portion 15c to the central portion) is roughened. Has been done.

The roughening can be realized by a plating layer having a plurality of protrusions formed by electrolytic plating, for example. That is, since the plating layer is formed on the first surface 15a and the second surface 15b of the electrode plate 15, the molten resin is formed by roughening at the joint interface with each resin frame on each surface. It penetrates between the plurality of formed projections and exerts an anchor effect. Thereby, the bonding strength between the electrode plate 15 and each resin frame can be improved.

The total of the thickness of the electrode plate 15 of the bipolar electrode 14 and the thickness of the resin frame 21 (hereinafter referred to as “first thickness”) T1 (see FIG. 3), the thickness of the electrode plate 15 of the negative terminal electrode 18, and the pair of resin frames. The total thickness T2 of 22 and 22 (hereinafter referred to as “second thickness”) (see FIG. 3), the total thickness of the electrode plate 15 of the positive electrode termination electrode 19 and the total thickness of the pair of resin frames 23 and 23 (hereinafter, T3 (referred to as "third thickness") (see FIG. 3) is all the same.

Specifically, the resin frames 22 and 23 have the same thickness. The thickness of the resin frame 21 is twice the thickness of the resin frames 22 and 23. The thickness of the electrode plate 15 of the bipolar electrode 14, the thickness of the electrode plate 15 of the negative electrode termination electrode 18, and the thickness of the electrode plate 15 of the positive electrode termination electrode 19 are all the same. The thickness of the resin frame 22 and the resin frame 23 is, for example, 75 μm. The thickness of the resin frame 21 is, for example, 150 μm. The thickness of the electrode plate 15 of the bipolar electrode 14, the negative terminal electrode 18, and the positive terminal electrode 19 is, for example, 75 μm. The first thickness T1, the second thickness T2, and the third thickness T3 are, for example, 225 μm.

The separator 13 is a member that prevents a short circuit between the electrode plates 15 and 15. The separator 13 is formed in a sheet shape, for example. Examples of the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), and a woven or non-woven fabric made of polypropylene, methylcellulose and the like. The separator 13 may be reinforced with a vinylidene fluoride resin compound. The separator 13 is not limited to the sheet shape, and a bag shape may be used.

The sealing body 12 is formed in a rectangular tubular shape as a whole. The sealing body 12 is provided on the side surface of the electrode laminated body 11 so as to surround the electrode laminated body 11. The sealing body 12 holds the peripheral edge portion 15c of the electrode plate 15 on the side surface. The sealing body 12 encloses the resin frames 21, 22, and 23 from the outside along the side surface, and includes a sealing portion 26 coupled to each of the resin frames 21, 22, and 23.

The sealing portion 26 is provided outside the electrode laminated body 11 and constitutes an outer wall (housing) of the electricity storage module 4. The sealing portion 26 is formed by, for example, injection molding of resin, and extends over the entire length of the electrode stacked body 11 along the stacking direction D1. The sealing portion 26 has a rectangular tubular shape (annular shape) extending in the stacking direction D1 as an axial direction. The sealing portion 26 is welded to the outer surface of each of the resin frames 21, 22, 23 by heat during injection molding, for example. Each of the resin frames 21, 22, 23 and the sealing portion 26 is, for example, an insulating resin having alkali resistance. Examples of constituent materials of the resin frames 21, 22, 23 and the sealing portion 26 include polypropylene (PP), polyphenylene sulfide (PPS), modified polyphenylene ether (modified PPE), and the like.

A resin frame 21, a resin frame 22 welded to the second surface 15b of the electrode plate 15 of the negative electrode termination electrode 18, a resin frame 23 welded to the first surface 15a of the electrode plate 15 of the positive electrode termination electrode 19, and a seal. The stopper 26 forms an internal space V between adjacent electrodes and seals the internal space V. More specifically, the sealing portion 26 seals the internal space V formed by the electrode plate 15 of the bipolar electrodes 14 and the resin frame 21 that are adjacent to each other along the stacking direction D1. The sealing portion 26 seals the internal space V formed by the electrode plate 15 of the negative electrode termination electrode 18 and the electrode plate 15 of the bipolar electrode 14, and the resin frame 21 and the resin frame 22 which are adjacent to each other along the stacking direction D1. To do. The sealing portion 26 seals the internal space V formed by the electrode plate 15 of the positive electrode termination electrode 19 and the electrode plate 15 of the bipolar electrode 14 and the resin frame 23 which are adjacent to each other along the stacking direction D1. Each internal space V is airtightly partitioned. Each 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.

In the electricity storage module 4, as shown in FIG. 4, a space VB that is surrounded by the electrode plate 15 of the negative terminal electrode 18 and the pair of resin frames 22 and 22 and that does not contain the electrolytic solution is formed. When viewed from the stacking direction D1, the space VB is formed so as to surround the outside of the peripheral edge portion 15c of the electrode plate 15 of the negative electrode termination electrode 18. The space VB is surrounded by the electrode plate 15 of the negative terminal electrode 18, the pair of resin frames 22 and 22, and the sealing portion 26. The space VB is formed by welding each of the pair of resin frames 22 and 22 and the electrode plate 15 of the negative terminal electrode 18 and welding the pair of resin frames 22 and 22 and the sealing portion 26. Has been formed. The space VB has a substantially rectangular shape when viewed from the cross section along the stacking direction D1. The space VB is formed by welding the pair of resin frames 22 and 22 and the electrode plate 15 of the negative terminal electrode 18, and by welding the pair of resin frames 22 and 22 to each other. May be.

Next, a welding machine used in the method for manufacturing the electricity storage module 4 according to the present embodiment will be described. As shown in FIG. 5, the welding machine 80 includes a pair of pressure members 81 and 82. The pair of pressing members 81 and 82 are arranged so as to face each other. The pair of pressure members 81, 82 are separated from each other. The pressure member 81 has a pair of rollers 83, 83, an endless belt 84 wound around the pair of rollers 83, 83, a pressure roller 85, a heater 86, and a cooling plate 87. There is. The belt 84 is driven by the pair of rollers 83, 83. The pressure bonding roller 85, the heater 86, and the cooling plate 87 are arranged between the pair of rollers 83, 83 and on the inner peripheral side of the belt 84. The pressure roller 85 is separated from the pressure member 82 by a predetermined distance. The clearance between the pressure members 81 and 82 is kept constant by the pressure roller 85. The clearance is appropriately adjusted according to the thickness of the work W conveyed between the pair of pressure members 81 and 82. As a result, the work W can be welded while appropriately applying a pressing force. The pair of pressure members 81 and 82 can weld the work W conveyed between the pair of pressure members 81 and 82.

Next, a method for manufacturing the electricity storage module 4 according to the present embodiment will be described with reference to FIG. As shown in FIG. 6, the method for manufacturing the electricity storage module 4 according to the present embodiment includes a first preparation step S1, a first welding step S2, a second preparation step S3, a second welding step S4, and a third preparation step S5. The third welding step S6 and the laminating step S7 are included.

In this manufacturing method, first, the bipolar electrode 14 and the resin frame 21 are prepared (first preparation step S1). Subsequently, while pressing the resin frame 21 arranged in the peripheral edge portion 15c of the first surface 15a of the electrode plate 15 of the bipolar electrode 14 and prepared in the first preparation step S1 by the pair of pressing members 81 and 82. The electrodes are welded to form the bipolar electrode unit 31 (first welding step S2). Specifically, the clearance between the pair of pressure members 81 and 82 is adjusted according to the first thickness T1.

The bipolar electrode 14 and the resin frame 21 are a pair of pressurizing members adjusted to have a predetermined clearance in a state where the resin frame 21 is temporarily fixed to the peripheral edge portion 15c of the first surface 15a of the electrode plate 15 of the bipolar electrode 14. It is conveyed between 81 and 82. The electrode plate 15 of the bipolar electrode 14 and the resin frame 21 are heated by the heater 86, pressed by the pressure roller 85, and then cooled by the cooling plate 87. The above heating, pressurization and cooling are performed over the peripheral portion 15c of the electrode plate 15 and the entire circumference of the resin frame 21. As a result, the resin frame 21 is welded to the electrode plate 15 of the bipolar electrode 14 to form the bipolar electrode unit 31.

Subsequently, the negative electrode termination electrode 18 and the pair of resin frames 22, 22 are prepared (second preparation step S3). Then, the pair of resin frames 22 and 22 arranged in such a manner as to sandwich the peripheral edge portion 15c of the electrode plate 15 of the negative electrode termination electrode 18 from the thickness direction and prepared in the second preparation step are connected to the pair of pressing members 81 and 82. Then, the negative electrode terminal electrode unit 32 is formed by welding while applying pressure (second welding step S4). Specifically, the negative electrode termination electrode 18 and the pair of resin frames 22 and 22 are arranged so that the pair of resin frames 22 and 22 sandwich the electrode plate 15 of the negative electrode termination electrode 18 between the first surface 15 a and the first surface 15 a of the electrode plate 15. The pair of resin frames 22, 22 is temporarily fixed to the peripheral edge portion 15c of the second surface 15b, and is conveyed between the pair of pressure members 81, 82 adjusted to have a predetermined clearance. In the second preparation step S3, the second thickness T2 is the same as the first thickness T1 of the first preparation step S1. Therefore, in the second welding step S4, it is not necessary to adjust the clearance between the pair of pressure members 81 and 82 again.

The negative terminal electrode 18 and the pair of resin frames 22 and 22 are conveyed between the pair of pressure members 81 and 82 so that the one resin frame 22 faces the pressure member 81. The electrode plate 15 of the negative terminal electrode 18 and the resin frame 22 on one side are heated by the heater 86, pressed by the pressure roller 85, and then cooled by the cooling plate 87. The above heating, pressurization and cooling are performed over the peripheral edge portion 15c of the electrode plate 15 and the entire circumference of the one resin frame 22. As a result, one resin frame 22 is welded to the electrode plate 15 of the negative terminal electrode 18.

Subsequently, in the negative electrode termination electrode 18 and the pair of resin frames 22, 22, one resin frame 22 is welded to the electrode plate 15 of the negative electrode termination electrode 18, and the other resin frame 22 is the electrode plate 15 of the negative electrode termination electrode 18. In the state where the other resin frame 22 is temporarily fixed to the pressure member 81, the resin frame 22 is conveyed between the pair of pressure members 81 and 82 so as to face the pressure member 81. The electrode plate 15 of the negative terminal electrode 18 and the other resin frame 22 are heated by the heater 86, pressed by the pressure roller 85, and then cooled by the cooling plate 87. The heating, pressurization, and cooling are performed over the peripheral edge portion 15c of the electrode plate 15 and the entire circumference of the other resin frame 22. As a result, the other resin frame 22 is welded to the electrode plate 15 of the negative electrode termination electrode 18 to form the negative electrode termination electrode unit 32. When the pressure member 82 provided with the heater 86 is used, the pair of resin frames 22 and 22 can be simultaneously welded to the electrode plate 15 of the negative terminal electrode 18.

In the second welding step S4, a space VB surrounded by the electrode plate 15 of the negative electrode termination electrode 18 and the pair of resin frames 22, 22 is formed. The space VB is formed by welding a pair of resin frames 22 and 22 to each other. In the second welding step S4, the pair of resin frames 22, 22 are mutually bonded when one resin frame 22 is welded to the electrode plate 15 or when the other resin frame 22 is welded to the electrode plate 15. It is welded.

Subsequently, the positive electrode terminal electrode 19 and the pair of resin frames 23, 23 are prepared (third preparation step S5). Then, the pair of resin frames 23, 23, which are arranged so as to sandwich the peripheral edge portion 15c of the electrode plate 15 of the positive electrode terminal electrode 19 from the thickness direction, and which are prepared in the third preparation step S5, the pair of pressing members 81, The positive electrode terminal electrode unit 33 is formed by welding while applying pressure by 82 (third welding step S6). Specifically, the positive electrode termination electrode 19 and the pair of resin frames 24, 24 are arranged such that the pair of resin frames 24, 24 sandwich the electrode plate 15 of the positive electrode termination electrode 19 between the first surface 15 a and the first surface 15 a of the electrode plate 15. The pair of resin frames 24, 24 is temporarily fixed to the peripheral edge portion 15c of the second surface 15b, and is conveyed between the pair of pressure members 81, 82 adjusted to have a predetermined clearance. In the third preparation step S5, the third thickness T3 is the same as the second thickness T2 of the second preparation step S3. Therefore, also in the third welding step S6, it is not necessary to adjust the clearance between the pair of pressure members 81 and 82, as in the second welding step S4.

The positive terminal electrode 19 and the pair of resin frames 23, 23 are conveyed between the pair of pressure members 81, 82 so that the one resin frame 23 faces the pressure member 81. The electrode plate 15 of the positive terminal electrode 19 and the one resin frame 23 are heated by the heater 86 and pressed by the pressure bonding roller 85, and then cooled by the cooling plate 87. The heating, pressurization, and cooling are performed over the peripheral edge portion 15c of the electrode plate 15 and the entire circumference of the one resin frame 23. As a result, one resin frame 23 is welded to the electrode plate 15 of the positive terminal electrode 19.

Subsequently, in the positive electrode termination electrode 19 and the pair of resin frames 23, 23, one resin frame 23 is welded to the electrode plate 15 of the positive electrode termination electrode 19, and the other resin frame 23 is the electrode plate 15 of the positive electrode termination electrode 19. In the state where the other resin frame 23 is temporarily fixed to the pressure member 81, the resin frame 23 is conveyed between the pair of pressure members 81 and 82 so as to face the pressure member 81. The electrode plate 15 of the positive terminal electrode 19 and the other resin frame 23 are heated by the heater 86, pressed by the pressure bonding roller 85, and then cooled by the cooling plate 87. The heating, pressurization, and cooling are performed over the peripheral edge portion 15c of the electrode plate 15 and the entire circumference of the other resin frame 23. As a result, the other resin frame 23 is welded to the electrode plate 15 of the positive electrode termination electrode 19 to form the positive electrode termination electrode unit 33. When the pressure member 82 provided with the heater 86 is used, the pair of resin frames 23, 23 can be welded to the electrode plate 15 of the positive electrode terminal electrode 19 at the same time.

Then, the bipolar electrode units 31 are stacked along the stacking direction D1 to form the bipolar electrode unit group 30 (see FIG. 3) (stacking step S7). In the stacking step S7, the negative electrode terminal electrode unit 32 is arranged such that the negative electrode 17 of the negative electrode terminal electrode 18 faces the bipolar electrode unit group 30 at one end of the bipolar electrode unit group 30 in the stacking direction D1. In the stacking step S7, the positive electrode terminal electrode unit 33 is arranged so that the positive electrode 16 of the positive electrode terminal electrode 19 faces the bipolar electrode unit group 30 at the other end of the bipolar electrode unit group 30 in the stacking direction D1.

Next, the effects of the power storage module 4 and the method of manufacturing the power storage module according to the present embodiment will be described with reference to FIG. 7. FIG. 7 is an enlarged cross-sectional view of a main part of an electricity storage module according to a comparative example. As shown in FIG. 7, the electricity storage module 100 according to the comparative example is different from the electricity storage module 4 according to the present embodiment in that the pair of resin frames 22 and 22 are not provided.

In the electricity storage module 100, due to the so-called alkaline creep phenomenon, the electrolytic solution existing in the internal space V propagates on the surface of the electrode plate 15 of the negative terminal electrode 18, and passes through the gap between the electrode plate 15 and the resin frame 22 to make the electrode plate. Bleeding may occur on the side of the first surface 15 a of 15. In FIG. 7, a moving path of the electrolytic solution L in the alkaline creep phenomenon is indicated by an arrow A. This alkaline creep phenomenon can occur during charging and discharging of the power storage module and under no load due to electrochemical factors and fluid phenomena. The alkaline creep phenomenon occurs due to the presence 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 present embodiment, the space VB surrounded by the electrode plate 15 of the negative terminal electrode 18 and the pair of resin frames 22 and 22 is formed on the path that can be the path of movement of the electrolytic solution. For this reason, between the electrode plate 15 of the negative electrode termination electrode 18 and the resin frame 22 welded to the second surface 15b of the electrode plate 15 of the negative electrode termination electrode 18, which is the starting point of the electrolyte leaching due to the alkaline creep phenomenon. It is possible to prevent the moisture contained in the outside air from entering the gap. Thereby, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and it is possible to suppress the electrolyte solution from seeping out of the power storage module 4. Further, in this embodiment, the positive electrode terminal electrode unit 33 has the resin frame 23 welded to both the first surface 15 a and the second surface 15 b of the electrode plate 15. As a result, when the internal pressure of the internal space V rises, for example, the positive electrode termination electrode 19 is deformed as compared with the case where the resin frame 23 is welded only to the first surface 15a or the second surface 15b of the electrode plate 15. Hard to do. As a result, it is possible to prevent the electrolyte from leaking and being damaged (for example, the resin frame 23 is damaged) on the positive electrode terminal electrode unit 33 side. As described above, the reliability of the power storage module 4 can be improved.

The first thickness T1, the second thickness T2, and the third thickness T3 are all the same. Therefore, once the clearance between the pair of pressure members is adjusted, the bipolar electrode unit 31, the negative electrode terminal electrode unit 32, and the positive electrode terminal electrode unit 33 are formed while the pressure is applied by the pair of pressure members 81 and 82. In each of these steps, it is not necessary to adjust the clearance between the pair of pressure members 81 and 82. Thereby, the productivity of the power storage module 4 can be improved.

The thickness of the electrode plate 15 of the bipolar electrode 14, the thickness of the electrode plate 15 of the negative electrode termination electrode 18, and the thickness of the electrode plate 15 of the positive electrode termination electrode 19 are all the same. Accordingly, by making the electrode plate 15 of the bipolar electrode 14, the electrode plate 15 of the negative electrode termination electrode 18, and the electrode plate 15 of the positive electrode termination electrode 19 have the same thickness, common parts can be achieved.

Further, in the present embodiment, in the second welding step S4, the space VB surrounded by the electrode plate 15 of the negative electrode termination electrode 18 and the pair of resin frames 22 and 22 is formed on the path that can be the path of movement of the electrolytic solution. There is. For this reason, between the electrode plate 15 of the negative electrode termination electrode 18 and the resin frame 22 welded to the second surface 15b of the electrode plate 15 of the negative electrode termination electrode 18, which is the starting point of the electrolyte leaching due to the alkaline creep phenomenon. It is possible to prevent the moisture contained in the outside air from entering the gap. Thereby, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and it is possible to suppress the electrolyte solution from seeping out of the power storage module 4. Further, in the present embodiment, in the third welding step S6, the positive electrode terminal electrode unit 33 is welded with the resin frame 23 on both the first surface 15a and the second surface 15b of the electrode plate 15. Therefore, when the internal pressure of the internal space V rises, for example, the positive electrode termination electrode 19 is deformed as compared with the case where the resin frame 23 is welded only to the first surface 15a or the second surface 15b of the electrode plate 15. Hard to do. As a result, it is possible to prevent the electrolyte from leaking and being damaged (for example, the resin frame 23 is damaged) on the positive electrode terminal electrode unit 33 side. As a result, the reliability of the power storage module 4 formed by the method of manufacturing the power storage module 4 can be improved. The total thicknesses T1, T2, T3 of the respective members prepared in each of the first preparation step S1, the second preparation step S3, and the third preparation step S5 are the same. Therefore, once the clearance between the pair of pressure members 81 and 82 is adjusted, the pair of pressure members 81 and 82 are respectively adjusted in the first welding step S2, the second welding step S4, and the third welding step S6. It becomes unnecessary to adjust the clearance between 82. Thereby, the productivity of the power storage module 4 can be improved.

The present invention is not limited to the above embodiment.

As shown in FIGS. 8 and 9, the electrode stack 11 of the electricity storage module 4 may further include a metal plate unit 34. The metal plate unit 34 has a metal plate (uncoated metal plate) 20 and a pair of resin frames (resin members) 24, 24. The metal plate 20 is arranged outside the electrode plate 15 of the negative terminal electrode 18 in the stacking direction D1. The metal plate 20 is arranged so as to face the first surface 15 a of the electrode plate 15 of the negative terminal electrode 18. The metal plate 20 has one surface 20a facing the first surface 15a of the electrode plate 15 of the negative terminal electrode 18 and the other surface 20b opposite to the one surface 20a. The one surface 20a and the other surface 20b of the metal plate 20 are not coated with the positive electrode active material and the negative electrode active material, and the entire surfaces of the one surface 20a and the other surface 20b are uncoated regions. There is. That is, the metal plate 20 is an uncoated metal plate provided with neither the positive electrode 16 nor the negative electrode 17. The metal plate 20 is a rectangular metal foil made of nickel. The metal plate 20, the electrode plate 15 of the negative terminal electrode 18, the resin frame 24, and the resin frame 22 form a surplus space VA in which the electrolytic solution is not contained. 8 and 9, for convenience of description, a linear metal plate 20 is shown in a cross-sectional view, but when the power storage modules 4 are stacked via the conductive plate 5, the metal plate 20 is shown. Are in a state of being in electrical contact with the adjacent electrode plates 15 side.

The pair of resin frames 24, 24 are continuously provided over the entire circumference of the peripheral edge portion 20c on the one surface 20a and the other surface 20b of the metal plate 20, respectively, and have a rectangular annular shape (frame shape) when viewed from the stacking direction D1. I am doing it. The pair of resin frames 24, 24 are welded to each of the one surface 20a and the other surface 20b of the metal plate 20 by, for example, ultrasonic waves or heat, and airtightly joined. That is, the pair of resin frames 24, 24 are welded to the peripheral edge portions 20c of the one surface 20a and the other surface 20b of the metal plate 20 so as to sandwich the metal plate 20 from the thickness direction. The resin frame 24 is, for example, a film having a predetermined thickness in the stacking direction D1. When viewed in the stacking direction D1, the inner edge of the resin frame 24 is located inside the edge of the metal plate 20. When viewed in the stacking direction D1, the outer edge of the resin frame 24 projects beyond the edge of the metal plate 20, and the tip portion thereof is embedded in the sealing body 12.

A region of the metal plate 20 welded to the resin frame 24 (a region where the peripheral edge portion 20c of the one surface 20a and the other surface 20b overlaps the resin frame 24) is roughened. The roughened region may be the overlapping region, but here, the entire one surface 20a and the other surface 20b of the metal plate 20 (the entire surface from the peripheral portion 20c to the central portion) is roughened.

The first thickness T1, the second thickness T2, the third thickness T3, the total thickness of the metal plate 20 and the thickness of the pair of resin frames 24, 24 (hereinafter referred to as "fourth thickness") T4 (see FIG. 9). ) Are all the same. Specifically, the resin frame 22, the resin frame 23, and the resin frame 24 have the same thickness. The thickness of the resin frame 21 is twice the thickness of the resin frame 24. The thickness of the electrode plate 15 of the bipolar electrode 14, the thickness of the electrode plate 15 of the negative electrode termination electrode 18, the thickness of the electrode plate 15 of the positive electrode termination electrode 19, and the thickness of the metal plate 20 are all the same. As a result, the resin frames 22, 23, 24 have the same thickness, and the electrode plate 15 of the bipolar electrode 14, the electrode plate 15 of the negative terminal electrode 18, the electrode plate 15 of the positive terminal electrode 19, and By making the thicknesses of the metal plates 20 the same, common parts can be achieved.

The method for manufacturing the electricity storage module 4 may further include a fourth preparation step S11 and a fourth welding step S12 (see FIG. 6 ). In the fourth preparation step S11, the metal plate 20 and the pair of resin frames 24, 24 are prepared. Subsequently, in the fourth welding step S12, similarly to the second welding step S4, the pair of resin frames 24 arranged so as to sandwich the peripheral edge portion 20c of the metal plate 20 from the thickness direction and prepared in the fourth preparation step S11. , 24 are welded while being pressed by the pair of pressing members 81, 82 (see FIG. 5) to form the metal plate unit 34. In the fourth preparation step S11, the fourth thickness T4 is the same as the third thickness T3 of the third preparation step S5. Therefore, also in the fourth welding step, it is not necessary to adjust the clearance between the pair of pressure members 81 and 82, as in the second welding step S4 and the third welding step S6.

Subsequently, in the laminating step S7, the metal plate unit 34 is arranged so as to face the first surface 15a of the electrode plate 15 of the negative terminal electrode 18.

By disposing the metal plate unit 34 so as to face the electrode plate 15 of the negative terminal electrode 18, an extra space VA is formed on a path that can be a path for moving the electrolytic solution. For this reason, between the electrode plate 15 of the negative electrode termination electrode 18 and the resin frame 22 welded to the second surface 15b of the electrode plate 15 of the negative electrode termination electrode 18, which is the starting point of the electrolyte leaching due to the alkaline creep phenomenon. It is possible to prevent the moisture contained in the outside air from entering the gap. Thereby, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and it is possible to suppress the electrolyte solution from seeping out of the power storage module 4. Therefore, the reliability of the power storage module 4 can be improved. The first thickness T1, the second thickness T2, the third thickness T3, and the fourth thickness T4 are all the same. Therefore, once the clearance between the pair of pressure members 81 and 82 is adjusted, the bipolar electrode unit 31, the negative electrode terminal electrode unit 32, and the positive electrode terminal electrode unit are pressurized while being pressed by the pair of pressure members 81 and 82. In each step of forming 33 and the metal plate unit 34, it becomes unnecessary to adjust the clearance between the pair of pressure members 81 and 82. Thereby, the productivity of the power storage module 4 can be improved.

Further, in the stacking step S7, by disposing the metal plate unit 34 so as to face the electrode plate 15 of the negative electrode termination electrode 18, the surplus space VA is formed on the path that can serve as the electrolyte migration path. For this reason, between the electrode plate 15 of the negative electrode termination electrode 18 and the resin frame 22 welded to the second surface 15b of the electrode plate 15 of the negative electrode termination electrode 18, which is the starting point of the electrolyte leaching due to the alkaline creep phenomenon. It is possible to prevent the moisture contained in the outside air from entering the gap. Thereby, it is possible to suppress the influence of external humidity, which is the acceleration condition of the alkaline creep phenomenon, and it is possible to suppress the electrolyte solution from seeping out of the power storage module 4. Therefore, the reliability of the power storage module 4 formed by the method of manufacturing the power storage module 4 can be improved. Further, the total thickness T1, T2, T3, T4 of the respective members prepared in each of the first preparation step S1, the second preparation step S3, the third preparation step S5, and the fourth preparation step is the same. Therefore, once the clearance between the pair of pressurizing members is appropriately adjusted, a pair of pressing members may be used in each of the first welding step S2, the second welding step S4, the third welding step S6, and the fourth welding step. It becomes unnecessary to adjust the clearance between the pressure members 81 and 82. Thereby, the productivity of the power storage module 4 can be improved.

Further, as shown in FIG. 10, in the bipolar electrode unit 31, instead of the resin frame 21 arranged on the first surface 15a of the electrode plate 15 of the bipolar electrode 14, the electrode plate 15 of the bipolar electrode 14 is formed in the thickness direction. It may have a pair of resin frames (resin members) 25, 25 welded to the peripheral portions 15c of the first surface 15a and the second surface 15b of the electrode plate 15 of the bipolar electrode 14 so as to be sandwiched between them. .. The first thickness T1, the second thickness T2, the third thickness T3, and the total thickness (fifth thickness) T5 of the electrode plate 15 of the bipolar electrode 14 and the pair of resin frames 25 are all the same. .. Specifically, the thickness of the resin frame 25, the thickness of the resin frame 22, and the thickness of the resin frame 23 are all the same. As a result, parts can be made common by making all the resin frames 25, 22, 23 have the same thickness.

In this case, in the first preparation step S1, the bipolar electrode 14 and the pair of resin frames 25, 25 are prepared. Subsequently, in the first welding step S2, similarly to the second welding step S4, the pair of resins prepared in the first preparation step S1 so as to sandwich the peripheral edge portion 15c of the electrode plate 15 of the bipolar electrode 14 from the thickness direction. The frames 25, 25 are welded while being pressed by the pair of pressing members 81, 82 (see FIG. 5) to form the bipolar electrode unit 31.

Further, as shown in FIG. 11, the thickness of the pair of resin frames 25, 25 may be different from each other. The thickness of the pair of resin frames 22, 22 may be different from each other. The thickness of the pair of resin frames 23, 23 may be different from each other. As an example, the thickness of one resin frame 25 welded to the first surface 15a of the electrode plate 15 of the bipolar electrode 14 is equal to the thickness of the other resin frame 25 welded to the second surface 15b of the electrode plate 15 of the bipolar electrode 14. It may be smaller than the thickness of 25.

The method of welding the pair of resin frames so as to sandwich them from the thickness direction includes, as shown in the above embodiment and modification, a pair of resin frames that are temporarily fixed to both sides of the metal plate of each unit. In addition to the method of transporting to a pressure member and welding, the following method can be considered. First, an intermediate member in which one resin frame is temporarily fixed to only one surface of the metal plate of each unit and is conveyed to a pair of pressure members, and one resin frame is welded to only one surface of the metal plate. To form. Next, while the other resin frame is temporarily fixed to the other surface of the intermediate member in which one resin frame is welded to only one surface of the metal plate, it is conveyed to the pair of pressure members, and both of the metal plates are welded. A unit member having a resin frame welded on its surface is formed.

That is, the thickness of one resin frame prepared in the first preparation step is smaller than the thickness of the other resin frame, and in the first welding step, after the other resin frame is welded to the metal plate of the bipolar electrode, One resin frame may be welded to the metal plate of the bipolar electrode. The thickness of one resin frame prepared in the second preparation step is smaller than the thickness of the other resin frame, and in the second welding step, after the other resin frame is welded to the metal plate of the negative electrode terminal, The resin frame may be welded to the metal plate of the negative terminal electrode. The thickness of one resin frame prepared in the third preparation step is smaller than the thickness of the other resin frame, and in the third welding step, after the other resin frame is welded to the metal plate of the positive electrode termination electrode, The resin frame may be welded to the metal plate of the positive terminal electrode.

When the resin frame is welded to the metal plate of the unit, energy is supplied from the metal plate side with one resin frame temporarily fixed to one surface of the metal plate. However, since one resin frame is already welded to one surface of the intermediate member, energy cannot be supplied from the metal plate side in order to weld the other resin frame. In this case, the other resin frame to be subsequently welded is welded to the electrode plate by the energy transmitted through the resin frame, not the energy transmitted through the metal plate.

Here, in the case of welding the resin frames having the same thickness, supplying the energy via the metal plate can weld the resin frame with less energy than supplying the energy via the resin frame. Therefore, by welding the other resin frame having a large thickness to the electrode plate first and the one resin frame having a small thickness to the electrode plate later, one resin frame is efficiently welded to the metal plate with less energy. can do.

In the above embodiment, the first preparation step S1, the first welding step S2, the second preparation step S3, the second welding step S4, the third preparation step S5, the third welding step S6, and the laminating step S7 are performed in this order. However, the present invention is not limited to this. Regarding each preparation step and each welding step, the first preparation step S1 is performed before the first welding step S2, the second preparation step S3 is performed before the second welding step S4, and the third welding step S6 is performed. The order of other implementations is not limited as long as the third preparation step S5 is performed before. The order in which the bipolar electrode unit 31, the negative electrode termination electrode unit 32, and the positive electrode termination electrode unit 33 are formed is not limited.

Similarly, when the manufacturing method of the electricity storage module 4 further includes the fourth welding step S11 and the fourth preparation step S12, the respective preparation steps and the respective welding steps are similar to each other before the fourth welding step S11. As long as S12 is carried out, the order of other implementations is not limited. The order in which the bipolar electrode unit 31, the negative electrode termination electrode unit 32, the positive electrode termination electrode unit 33, and the metal plate unit 34 are formed is not limited.

Although the resin frame 21 is welded to the peripheral edge portion 15c of the first surface 15a of the electrode plate 15 of the bipolar electrode 14 in the above-described embodiment, the resin frame 21 is the same as that of the electrode plate 15 of the bipolar electrode 14. It may be welded to the peripheral portion 15c of the second surface 15b.

In the above embodiment, the metal plate 20 may have a contact portion that contacts the electrode plate 15 of the negative electrode termination electrode 18.

4... Electric storage module, 14... Bipolar electrode, 15... Electrode plate (metal plate), 15a... 1st surface, 15b... 2nd surface, 15c... Edge part, 16... Positive electrode (positive electrode active material), 17... Negative electrode (Negative electrode active material), 18... Negative electrode, 19... Positive electrode, 20... Metal plate (uncoated metal plate), 20a... One surface, 20b... Other surface, 20c... Peripheral part, 21... Resin frame (resin member), 22... Resin frame (resin member), 23... Resin frame (resin member), 24... Resin frame (resin member), 25... Resin frame (resin member), 30... Bipolar electrode unit group, 31... Bipolar electrode unit, 32... Negative termination electrode unit, 33... Positive termination electrode unit, D1... Stacking direction (one direction), V... Internal space, VB... Space.

Claims (10)

At least one bipolar electrode made of a metal plate coated with a positive electrode active material on one surface and coated with a negative electrode active material on the other surface opposite to the one surface, and at least one frame-shaped resin member A first preparatory step
A bipolar member is formed by welding a resin member, which is disposed on at least one of the peripheral portions of the one surface and the other surface of the metal plate of the bipolar electrode, and which is prepared in the first preparing step, while applying pressure with a pair of pressure members. A first welding step of forming an electrode unit,
A second preparation step of preparing a negative electrode terminal electrode made of a metal plate having one surface coated with a negative electrode active material, and a pair of frame-shaped resin members;
The negative electrode terminal is arranged by sandwiching the peripheral portion of the metal plate of the negative electrode termination electrode from the thickness direction, and welding the pair of resin members prepared in the second preparation step while pressurizing them with the pair of pressure members. A second welding step of forming an electrode unit,
A third preparation step of preparing a positive electrode terminal electrode formed of a metal plate having one surface coated with a positive electrode active material, and a pair of frame-shaped resin members;
A pair of resin members, which are arranged so as to sandwich the peripheral edge portion of the metal plate of the positive electrode termination electrode from the thickness direction, are welded while pressing the pair of resin members prepared in the third preparation step while being pressed by the pair of pressing members. A third welding step of forming an electrode unit,
The bipolar electrode units are stacked along one direction, and the negative electrode active material of the negative terminal electrode faces the bipolar electrode unit group at one end of the bipolar electrode unit group including the plurality of bipolar electrode units in the one direction. Thus, the negative electrode termination electrode unit is arranged, and the positive electrode termination electrode is arranged so that the positive electrode active material of the positive electrode termination electrode faces the bipolar electrode unit group at the other end of the bipolar electrode unit group in the one direction. A stacking step of arranging the units,
Of the total thickness of the metal plate and the resin member of the bipolar electrode prepared in the first preparing step, and the thickness of the metal plate of the negative terminal electrode and the pair of resin members prepared in the second preparing step. The total thickness, the total thickness of the metal plate of the positive electrode terminal electrode and the total thickness of the pair of resin members prepared in the third preparation step are the same,
In the second welding step, a method of manufacturing an electricity storage module, wherein a space surrounded by the metal plate of the negative electrode terminal electrode and a pair of resin members is formed. An uncoated metal plate not coated with an active material, and a fourth preparation step of preparing a pair of frame-shaped resin members;
The metal plate is arranged such that the peripheral edge of the uncoated metal plate is sandwiched from the thickness direction, and a pair of resin members prepared in the fourth preparing step are welded while being pressed by the pair of pressing members. And a fourth welding step of forming a unit,
Of the total thickness of the metal plate and the resin member of the bipolar electrode prepared in the first preparing step, and the thickness of the metal plate of the negative terminal electrode and the pair of resin members prepared in the second preparing step. The total thickness, the total thickness of the metal plate of the positive electrode termination electrode and the pair of resin members prepared in the third preparation step, and the uncoated metal plate prepared in the fourth preparation step. And the total thickness of the pair of resin members are all the same,
The manufacturing of the electricity storage module according to claim 1, wherein, in the stacking step, the metal plate unit is arranged so as to face the other surface of the metal plate of the negative electrode that is not coated with the negative electrode active material. Method. In the first preparation step, a pair of resin members are prepared,
In the first welding step, the pair of resin members that are arranged so as to sandwich the peripheral edge of the metal plate of the bipolar electrode from the thickness direction and that are prepared in the first preparation step are pressed by the pair of pressing members. The method for manufacturing an electricity storage module according to claim 1 or 2, wherein the electrical storage module is welded while being welded. In the third preparatory step, the thickness of each resin member in the pair of resin members prepared in the first preparing step, the thickness of each resin member in the pair of resin members prepared in the second preparing step, The method for manufacturing an electricity storage module according to claim 3, wherein the thickness of each resin member in the pair of prepared resin members is the same. The thickness of the metal plate of the bipolar electrode prepared in the first preparing step, the thickness of the metal plate of the negative terminal electrode prepared in the second preparing step, and the positive electrode prepared in the third preparing step. The method for manufacturing an electricity storage module according to any one of claims 1 to 4, wherein the thickness of the metal plate of the terminal electrode is all the same. A positive electrode active material is coated on one surface, and a bipolar electrode made of a metal plate on which the negative electrode active material is coated on the other surface opposite to the one surface, and one surface of the metal plate of the bipolar electrode And a bipolar electrode unit having a frame-shaped resin member that is welded to at least one of the peripheral edges of the other surface,
A negative electrode terminal electrode made of a metal plate coated with a negative electrode active material on one surface, and a pair welded so as to be sandwiched from the thickness direction to the peripheral portions of one surface and the other surface of the metal plate of the negative electrode terminal electrode. A negative electrode terminal electrode unit having a frame-shaped resin member of
A positive electrode terminating electrode made of a metal plate having one surface coated with a positive electrode active material, and a pair welded so as to be sandwiched from the thickness direction to the peripheral portions of one surface and the other surface of the metal plate of the positive electrode terminating electrode. And a positive electrode terminal electrode unit having a frame-shaped resin member,
The negative electrode terminal electrode unit, at one end in the one direction of a bipolar electrode unit group consisting of a plurality of the bipolar electrode unit stacked along one direction, the negative electrode active material of the negative electrode terminal electrode and the bipolar electrode unit group. Arranged to face each other,
The positive electrode termination electrode unit is arranged at the other end of the bipolar electrode unit group in the one direction so that the positive electrode active material of the positive electrode termination electrode faces the bipolar electrode unit group.
The total thickness of the metal plate of the bipolar electrode and the resin member of the bipolar electrode unit, the total thickness of the metal plate of the negative terminal electrode and the thickness of the pair of resin members of the negative terminal electrode unit, and the positive electrode. The thickness of the metal plate of the terminal electrode and the total thickness of the pair of resin members of the positive electrode terminal electrode unit are all the same,
A space surrounded by the metal plate of the negative terminal electrode and the pair of resin members of the negative terminal electrode unit is formed,
An electricity storage module in which an electrolytic solution containing an alkaline solution is contained in an internal space formed by the metal plate of the bipolar electrode, the metal plate of the negative electrode terminal, and the resin member of the bipolar electrode unit. In the metal plate of the negative electrode terminal electrode, the negative electrode active material is arranged so as to face the other surface not coated, an uncoated metal plate not coated with an active material, and the uncoated metal plate. Further comprising a metal plate unit having a pair of frame-shaped resin members that are welded to the peripheral edge portions on one surface and the other surface of the metal plate so as to be sandwiched from the thickness direction,
The total thickness of the metal plate of the bipolar electrode and the resin member of the bipolar electrode unit, the total thickness of the metal plate of the negative terminal electrode and the thickness of the pair of resin members of the negative terminal electrode unit, and the positive electrode. The total thickness of the metal plate of the terminal electrode and the thickness of the pair of resin members of the positive electrode terminal electrode unit, and the total thickness of the uncoated metal plate and the pair of resin members of the metal plate unit, The electricity storage module according to claim 6, which is all the same. The said bipolar electrode unit has a pair of resin member welded so that it may pinch|interpose from the thickness direction to the peripheral part in the one surface and the other surface of the metal plate of the said bipolar electrode. Power storage module. The thickness of each resin member in the pair of resin members included in the bipolar electrode unit, the thickness of each resin member in the pair of resin members included in the negative electrode terminal electrode unit, and the pair of resin members included in the positive electrode terminal electrode unit The electric storage module according to claim 8, wherein all the resin members have the same thickness. The thickness of the metal plate of the said bipolar electrode, the thickness of the metal plate of the said negative electrode termination electrode, and the thickness of the metal plate of the said positive electrode termination electrode are all the same, The statement in any one of Claims 6-9. Power storage module.

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