JP2020053151A - Method for manufacturing power storage module - Google Patents

Abstract

To provide a method for manufacturing a power storage module capable of suppressing an outflow of a hydrogen gas to the outside.SOLUTION: A method for manufacturing a power storage module comprises the steps of: preparing a collector including a pair of plate surfaces; forming a positive electrode layer on one surface of the pair of plate surfaces; forming a negative electrode layer on the other surface of the pair of plate surfaces; forming a frame body covering at least a part of a peripheral part of the collector; laminating a collector provided with the frame body via a separator along a lamination direction crossing an extension direction in which the pair of plate surfaces extends; and welding the laminated frame bodies. The step of welding the laminated frame bodies heats the frame bodies not only from the extension direction but also from at least one of lamination directions.SELECTED DRAWING: Figure 4

Description

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

  BACKGROUND ART As a power storage device, a power storage module including a stacked body including a plurality of stacked bipolar electrodes is known. Patent Literature 1 below discloses a current collector having a conductive resin layer, a positive electrode active material layer electrically coupled to one surface of the current collector, and an electric coupling to the opposite surface of the current collector. There is disclosed a power storage module having a stacked body in which bipolar electrodes each including a negative electrode active material layer described above are stacked. The bipolar electrode is laminated via an adhesive layer and a sealing material.

JP 2011-204386 A

  The power storage module including the above-described bipolar electrode is applicable not only to a lithium ion battery but also to a nickel hydride battery or the like. Here, inside the power storage module, hydrogen gas may be generated during charge and discharge. When this hydrogen gas flows out, there is a problem that the battery life is deteriorated.

  An object of the present invention is to provide a method for manufacturing a power storage module capable of suppressing outflow of hydrogen gas to the outside.

  The present inventors have studied a hydrogen gas outflow path of a power storage module including a plurality of bipolar electrodes stacked in one direction (stacking direction). As a result, it has been found that hydrogen gas flows out from both ends of the power storage module in the stacking direction to the outside through a gap between frames for fixing the bipolar electrodes. In addition, the present inventors have found that the outflow of hydrogen gas from both ends is much larger than the outflow of hydrogen gas from the side surface of the power storage module. Furthermore, the present inventors have found that by filling the gap between the frame bodies, the outflow of hydrogen gas from the both ends to the outside is suppressed.

  The method for manufacturing a power storage module according to the present invention based on the above findings includes a step of preparing a current collector having a pair of plate faces, a step of forming a positive electrode layer on one of the pair of plate faces, Forming a negative electrode layer on the other side of the plate surface, forming a frame covering at least a part of the peripheral portion of the current collector, and intersecting in a direction in which the pair of plate surfaces extends. Along the laminating direction, a step of laminating the current collector provided with the frame via a separator, and a step of welding the laminated frames are provided. The frame is heated from the existing direction and the frame is heated from at least one of the laminating directions.

  In the step of welding the frames in the method for manufacturing a power storage module, the frames are heated from the extending direction and the frames are heated from at least one of the laminating directions. For this reason, compared with the case where the frame is simply heated from the extending direction, the laminated frames are better welded to each other. That is, compared to a case where the frames are simply heated from the extending direction, the welding region between the stacked frames can be enlarged. Therefore, it is possible to suppress the outflow of the hydrogen gas through the unwelded region in the frame.

  In the step of welding the frames, the frames may be heated from the extending direction and the frames may be heated from both the laminating directions. In this case, the welding region between the stacked frame bodies can be further enlarged. Therefore, the outflow of hydrogen gas to the outside through the unwelded region in the frame can be favorably suppressed.

  In the step of welding the frame members, when the frame members are heated by a heating jig having the first member and the second member to weld the stacked frame members, the first member is moved from the extending direction to the frame member. , And the second member may heat the frame from one side in the stacking direction. By using such a heating jig, the welded region between the laminated frames can be favorably enlarged.

  The first member and the second member may be separated from each other. In this case, heating according to the position of the frame can be easily performed.

  In the step of welding the frames, the frames are heated by a heating jig and a heat conducting jig, and when the laminated frames are welded, the heating jig heats the frames from the extending direction. The heat conduction jig may contact both the exposed surface of the frame positioned at one end in the stacking direction, which crosses in the stacking direction, and the heating jig. In this case, the frame body can be heated from the extending direction by the heating jig, and the frame body can be heated from one end in the stacking direction via the heat conducting jig. Therefore, the welded region between the laminated frames can be favorably enlarged.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrical storage module which can suppress the outflow of hydrogen gas to the outside can be provided.

FIG. 1 is a schematic cross-sectional view of a power storage device including a power storage module. FIG. 2 is a schematic sectional view showing the internal configuration of the power storage module shown in FIG. 3A to 3C are diagrams for explaining a method for manufacturing a power storage module. FIGS. 4A and 4B are diagrams for explaining a method for manufacturing a power storage module. FIG. 5 is a diagram for explaining a method for manufacturing a nickel-metal hydride battery according to a comparative example. FIG. 6 is a diagram illustrating a method for manufacturing the power storage module according to the first modification of the embodiment. FIG. 7 is a diagram illustrating a method for manufacturing the power storage module according to the second modification of the embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference symbols, without redundant description. The dimensional ratios in the drawings do not always match those described.

  First, a configuration of a power storage module manufactured by the method for manufacturing a power storage module according to the present embodiment and a power storage device including the power storage module will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view of a power storage device including a power storage module. In FIG. 1, a power storage device 1 is used as a battery of a vehicle such as a forklift, a hybrid vehicle, or an electric vehicle. The power storage device 1 includes a plurality (three in the present embodiment) of power storage modules 2. Each power storage module 2 is, for example, a nickel-metal hydride battery that is a secondary battery. The power storage modules 2 overlap along a predetermined direction. Hereinafter, the direction in which the power storage modules 2 are stacked is simply referred to as a “stacking direction (Z-axis direction)”. Also, a direction that intersects or intersects perpendicularly with the lamination direction is defined as a horizontal direction. The horizontal direction has, for example, an X-axis direction and a Y-axis direction orthogonal to each other. In the present embodiment, “view from the stacking direction” corresponds to a plan view.

  A conductive plate 3 is provided between adjacent power storage modules 2. The conductive plates 3 are also arranged outside the power storage modules 2 located at both ends in the stacking direction. The power storage module 2 and the conductive plate 3 have, for example, a rectangular shape in plan view. The conductive plate 3 is electrically connected to an adjacent power storage module 2. Thereby, a plurality of power storage modules 2 are connected in series in the Z-axis direction. The power storage module 2 will be described later in detail.

  A positive electrode terminal 4 is connected to the conductive plate 3 located at one end (the lower end in the present embodiment) in the stacking direction. A negative electrode terminal 5 is connected to the conductive plate 3 located at the other end (the upper end in the present embodiment) in the stacking direction. Each of the positive electrode terminal 4 and the negative electrode terminal 5 extends, for example, in the X-axis direction. By providing such a positive electrode terminal 4 and a negative electrode terminal 5, charging and discharging of the power storage device 1 can be performed.

  Conductive plate 3 can also function as a heat sink in power storage device 1. The conductive plate 3 can release heat generated in the power storage module 2, for example. The conductive plate 3 is provided with a plurality of gaps 3a extending in the Y-axis direction, for example. When a coolant such as air passes through these gaps 3a, heat from the power storage module 2 can be efficiently released to the outside.

  The power storage device 1 includes a restraining unit 6 that restrains the power storage module 2 and the conductive plate 3 in the stacking direction. The restraining unit 6 includes a pair of restraining plates 7 that sandwich the power storage module 2 and the conductive plate 3 in the stacking direction, and a plurality of sets of bolts 8 and nuts 9 that fasten the restraining plates 7 to each other.

  The restraint plate 7 is a plate member formed of a metal such as iron. An insulating film 10 such as a resin film is arranged between each restraining plate 7 and the conductive plate 3. The constraint plate 7 and the insulating film 10 have a rectangular shape in a plan view, for example. Restraint plate 7 is larger than power storage module 2, conductive plate 3 and insulating film 10 in plan view.

  A plurality of insertion holes 7a through which the shaft 8a of the bolt 8 is inserted are provided in the edge of the constraint plate 7. With the nut 8 screwed into the tip of the shaft 8a with the shaft 8a of the bolt 8 inserted through the insertion hole 7a of each restraint plate 7, the power storage module 2, the conductive plate 3 and the insulating film 10 It is sandwiched between a pair of constraint plates 7. Thereby, a restraining load in the stacking direction is applied to the power storage module 2, the conductive plate 3, and the insulating film 10. The edge portion corresponds to a position of the restraining plate 7 that does not overlap the power storage module 2, the conductive plate 3, and the insulating film 10 in the stacking direction.

  FIG. 2 is a schematic sectional view showing the internal configuration of the power storage module shown in FIG. 2, the power storage module 2 has a structure in which a plurality of cells (for example, 24 cells) are stacked. The power storage module 2 includes an electrode stack 13 and a cylindrical resin portion 14 surrounding the electrode stack 13. The electrode laminate 13 is a laminate of the bipolar electrode 11 and the separator 12.

  The bipolar electrode 11 and the separator 12 are stacked on each other along the stacking direction, and have a rectangular shape in plan view, for example. The separator 12 is arranged between the adjacent bipolar electrodes 11. The bipolar electrode 11 includes a current collector 15 having a pair of plate surfaces 15a and 15b, a positive electrode layer 16 located on the plate surface 15a which is one of the pair of plate surfaces 15a and 15b, and a pair of plate surfaces 15a and 15b. And a negative electrode layer 17 located on a plate surface 15b which is the other surface of the negative electrode layer 15b.

  The current collector 15 is a conductor having a plate shape extending in the horizontal direction, and exhibits flexibility. Therefore, the horizontal direction can be said to be the extending direction of the current collector 15. The current collector 15 is, for example, a nickel foil, a plated steel plate, or a plated stainless steel plate. Examples of the steel sheet include a cold-rolled steel sheet (such as SPCC) specified in JIS G 3141: 2005. As the stainless steel plate, for example, SUS304 specified in JIS G 4305: 2015 is exemplified. The thickness of the current collector 15 is, for example, 0.1 μm or more and 1000 μm or less.

  The positive electrode layer 16 of the bipolar electrode 11 faces the negative electrode layer 17 of one of the bipolar electrodes 11 adjacent in the laminating direction with the separator 12 interposed therebetween. The positive electrode layer 16 is formed by applying a positive electrode active material to the plate surface 15 a of the current collector 15. The positive electrode active material is, for example, nickel hydroxide. The nickel hydroxide may be coated with a cobalt oxide or the like.

  The negative electrode layer 17 of the bipolar electrode 11 faces the positive electrode layer 16 of the other bipolar electrode 11 adjacent in the laminating direction with the separator 12 interposed therebetween. The negative electrode layer 17 is formed by applying a negative electrode active material to the plate surface 15 b of the current collector 15. The negative electrode active material is, for example, a hydrogen storage alloy. The peripheral portion 15c of the current collector 15 is an uncoated region where the positive electrode active material and the negative electrode active material are not applied.

  On the lowermost layer of the electrode stack 13, a positive terminal electrode 18 is arranged. The positive-electrode-side termination electrode 18 has a current collector 15 and a positive electrode layer 16 formed on a plate surface 15a of the current collector 15. On the uppermost layer of the electrode stack 13, a negative electrode side termination electrode 19 is arranged. The negative terminal electrode 19 includes the current collector 15 and the negative electrode layer 17 formed on the plate surface 15 b of the current collector 15. The positive electrode layer 16 of the positive terminal electrode 18 faces the negative electrode layer 17 of the lowermost bipolar electrode 11 with the separator 12 interposed therebetween. The negative electrode layer 17 of the negative terminal electrode 19 faces the positive electrode layer 16 of the uppermost bipolar electrode 11 with the separator 12 interposed therebetween. The current collectors 15 of the positive terminal electrode 18 and the negative terminal electrode 19 are electrically connected to the conductive plates 3 (see FIG. 1) adjacent in the laminating direction.

  The separator 12 is a member for separating the positive electrode layer 16 and the negative electrode layer 17 and is disposed between the positive electrode layer 16 and the negative electrode layer 17. The separator 12 is smaller than the current collector 15 and larger than the positive electrode layer 16 and the negative electrode layer 17 in plan view. The separator 12 has, for example, a sheet shape. The separator 12 is a porous film made of a polyolefin-based resin such as polyethylene (PE) or polypropylene (PP). The separator 12 may be formed of a nonwoven fabric or a woven fabric made of PE, PP, methylcellulose, or the like. The separator 12 may be reinforced with a vinylidene fluoride resin compound or the like. In addition, the shape of the separator 12 is not limited to a sheet shape, and may be a bag shape.

  The resin portion 14 is a resin member configured to surround the electrode stack 13. The resin portion 14 has, for example, a rectangular frame shape in a plan view. That is, the resin portion 14 has, for example, a rectangular tube shape. The resin portion 14 has a plurality of primary seal portions 20 that cover the peripheral portion 15c of each current collector 15, and a secondary seal portion 21 disposed around the primary seal portion 20. The primary seal portion 20 and the secondary seal portion 21 are formed of a resin such as, for example, polypropylene (PP), polyphenylene sulfide (PPS), or modified polyphenylene ether (modified PPE).

  The primary seal portion 20 is a member that holds the corresponding bipolar electrode 11 and is a frame that covers each edge of the corresponding bipolar electrode 11 over the entire circumference. In the stacking direction, the thickness of the primary seal portion 20 is larger than the sum of the thickness of the bipolar electrode 11 and the thickness of the separator 12. The primary seal portion 20 is formed, for example, by being liquid-tightly and air-tightly welded to the bipolar electrode 11. The primary seal portion 20 has an outer peripheral surface 20a that is an exposed surface that intersects in the horizontal direction. The distance S1 between the outer peripheral surface 20a and the current collector 15 in the horizontal direction is, for example, 1.5 mm.

  The primary seal portions 20 adjacent in the laminating direction are welded to each other in a liquid-tight and air-tight manner. Specifically, a partial region 20b (welding region) between the adjacent primary seal portions 20 is welded and integrated. That is, between the adjacent primary seal portions 20, there are both a region 20b integrated by welding and a region that is not welded and not integrated (unwelded region). The integrated region 20b is located closer to the outer peripheral surface 20a than the non-integrated region. As a result, an internal space V is formed between the adjacent bipolar electrodes 11 so as to be liquid-tightly and air-tightly partitioned by the bipolar electrodes 11 and 11 and the primary seal portion 20. Although not shown, the internal space V contains, for example, an aqueous electrolyte solution (specifically, an alkaline electrolyte such as a potassium hydroxide aqueous solution, a lithium hydroxide aqueous solution, or a mixture thereof). . This electrolytic solution is accommodated in the internal space V via a communication hole (not shown) provided in the primary seal portion 20. The communication hole is closed by, for example, a pressure regulating valve after the injection of the electrolyte. Note that, when referring to the “volume of the internal space”, it means the volume including the void of the separator 12.

  The secondary seal portion 21 is a member that forms an outer wall of the resin portion 14, and has, for example, a rectangular cylindrical shape. The secondary seal 21 covers the outer peripheral surface 20 a of each primary seal 20. The inner peripheral surface of the secondary seal portion 21 is welded to the outer peripheral surface 20a of each primary seal portion 20. That is, the secondary seal part 21 is joined to the outer peripheral surface 20 a of the primary seal part 20.

  Next, an example of a method for manufacturing the power storage module 2 will be described with reference to FIGS. 3 (a) to 3 (c) and FIGS. 4 (a) and 4 (b). FIGS. 3A to 3C and FIGS. 4A and 4B are diagrams for explaining a method of manufacturing the power storage module 2.

  First, as shown in FIG. 3A, a current collector 15 having a pair of plate surfaces 15a and 15b is prepared (first step).

  Next, as shown in FIG. 3B, the positive electrode layer 16 is formed on the plate surface 15 a of the current collector 15, and the negative electrode layer 17 is formed on the plate surface 15 b of the current collector 15 (No. 2 steps). In the second step, for example, the positive electrode layer 16 is formed by applying a positive electrode active material on the plate surface 15a. Then, the negative electrode layer 17 is formed by applying a negative electrode active material on the plate surface 15b. After the second step, a bipolar electrode 11 is formed. In the second step, the positive electrode layer 16 may be formed after the negative electrode layer 17 is formed.

  Next, as shown in FIG. 3C, a primary seal portion 20 that covers at least a part of the peripheral edge portion 15c of the current collector 15 is formed (third step). In the third step, for example, the resin composition is injection-molded from the plate surface 15a side to the entire periphery of the peripheral portion 15c. Thereby, a part of the peripheral portion 15c is covered with the resin composition. Then, by curing the resin composition by cooling or the like, the primary seal portion 20 that is in close contact with the peripheral portion 15c is formed. After the third step, the bipolar electrode 11 provided with the primary seal portion 20 as a frame is formed.

  Next, as shown in FIG. 4A, the current collector 15 provided with the primary seal portion 20 as a frame is laminated via the separator 12 along the laminating direction (fourth step). . In the fourth step, a plurality of bipolar electrodes 11 are stacked while sandwiching the separator 12 between the adjacent bipolar electrodes 11 in the stacking direction. At this time, the positive terminal electrode 18 and the negative terminal electrode 19 are also laminated. Therefore, after the fourth step, the electrode laminate 13 is formed. After the fourth step, the primary seal portions 20 adjacent in the laminating direction come into contact with each other.

  Next, the laminated primary seal portions 20 are welded to each other (fifth step). By performing the fifth step, the plurality of bipolar electrodes 11 included in the electrode stack 13 can be temporarily fixed. Thereby, in the sixth step described later, the electrode laminate 13 can be easily accommodated in the mold. In the fifth step, first, the electrode stack 13 is sandwiched in the stacking direction using the pressing jig 40 having the pair of press sections 41 and 42. Each of the press portions 41 and 42 of the pressing jig 40 is a member having a rectangular plate shape, for example. The press section 41 includes a main body section 41a such as a metal plate and a heat insulating section 41b that covers an edge of the main body section 41a. The press section 42 includes a main body section 42a such as a metal plate and a main body section 42a. And a heat insulating portion 42b that covers the edge of. The heat insulating portions 41b and 42b may show not only heat insulating properties but also electrical insulating properties. In the fifth step, the press section 41 is in contact with the lowermost layer of the electrode stack 13, and the press section 42 is in contact with the uppermost layer of the electrode stack 13. Here, the edges of the press portions 41 and 42 are located inside the outer peripheral edge of the primary seal portion 20 and outside the inner peripheral edge of the primary seal portion 20 in plan view. Therefore, in a plan view, each of the press parts 41 and 42 is in contact with a part of the corresponding primary seal part 20, and the other part of each primary seal part 20 is exposed from the press parts 41 and 42.

  In plan view, the edges of the press sections 41 and 42 may be located outside the peripheral edge 15 c of the current collector 15. In this case, the electrode laminate 13 is satisfactorily held between the press sections 41 and 42. In addition, the edges of the main bodies 41a and 42a may be located inside the peripheral edge 15c of the current collector 15 in plan view. Thereby, at the time of welding described later, the primary seal portion 20 can be reliably heated from multiple directions. Alternatively, the edges of the press portions 41 and 42 may be located inside the peripheral edge portion 15c of the current collector 15 in plan view. In this case, the primary seal portion 20 can be satisfactorily heated from multiple directions during welding, which will be described later. When the edges of the press parts 41 and 42 are located inside the peripheral edge part 15c of the current collector 15, the edges of the main body parts 41a and 42a are located outside the inner peripheral edge of the primary seal part 20 in plan view. May be located. In this case, the electrode laminate 13 is securely held by the press sections 41 and 42.

  In the fifth step, subsequently, the surfaces of the primary seal portion 20 exposed from the press portions 41 and 42 are heated. Thereby, the laminated primary seal portions 20 are welded to each other. Specifically, the outer peripheral surface 20 a of each primary seal portion 20, the exposed surface 20 c of the primary seal portion 20 located at the lower end (one end) of the electrode laminate 13 and exposed from the press portion 41, The exposed surface 20 d of the primary seal portion 20 located on the uppermost layer and exposed from the press portion 42 is heated using the heating jig 50. At this time, by heating the primary seal portions 20 from both the horizontal direction and the laminating direction, some of the regions 20b of the primary seal portions 20 are welded and integrated. Note that each of the exposed surfaces 20c and 20d is a surface that intersects the laminating direction. In the fifth step, for example, the heating jig 50 set at 240 ° C. is brought into contact with the primary seal portion 20 for 2 minutes.

  The heating jig 50 used in the fifth step is a heater for heating the primary seal portion 20 and has, for example, a substantially rectangular cylindrical shape. Although not shown, the heating jig 50 can be disassembled into two or more parts. The heating jig 50 includes a main body 51 extending in the laminating direction, a first protruding portion 52 protruding in a horizontal direction from one end (the lower end in the present embodiment) of the main body 51 in the laminating direction, A second protruding portion 53 that protrudes along the horizontal direction from the other end (the upper end in the present embodiment) of the main body portion 51 in the direction. The main body portion 51 is a member that comes into contact with the outer peripheral surface 20a of each primary seal portion 20, and has a rectangular frame shape in plan view. Each of the first projecting portion 52 and the second projecting portion 53 is located inside the main body portion 51 in plan view, and has a rectangular frame shape in plan view. The first protrusion 52 is a member that comes into contact with the exposed surface 20 c of the primary seal 20 located at the lower end of the electrode stack 13. When the primary seal part 20 is heated, the first protruding part 52 comes into contact with the heat insulating part 41 b of the press part 41. The second protrusion 53 is a member that comes into contact with the exposed surface 20 d of the primary seal 20 located at the upper end of the electrode stack 13. When the primary seal portion 20 is heated, the second projecting portion 53 comes into contact with the heat insulating portion 42b of the press portion 42. The main body 51, the first protrusion 52, and the second protrusion 53 are integrated with each other.

  Next, the resin part 14 shown in FIG. 2 is formed by forming the secondary seal part 21 covering the outer peripheral surface 20a of the primary seal part 20 (sixth step). In the sixth step, the resin composition is injection-molded on the entire outer peripheral surface 20a using, for example, a mold. Then, the secondary sealing portion 21 is formed by curing the resin composition by cooling or the like. After completion of the sixth step, an electrolytic solution is accommodated in the internal space V defined by the adjacent bipolar electrodes 11 and the primary seal portion 20. Through the above steps, the power storage module 2 is manufactured.

  Hereinafter, the operation and effect of the power storage module manufactured by the manufacturing method according to the present embodiment will be described with reference to a comparative example illustrated in FIG. FIG. 5 is a diagram for explaining a method for manufacturing a nickel-metal hydride battery according to a comparative example.

  The heating jig 150 shown in FIG. 5 differs from the present embodiment in that the heating jig 150 does not include the first protrusion and the second protrusion. Further, in the comparative example, the outer peripheral edge of the primary seal portion 120 and the edges of the press portions 141 and 142 in a plan view are aligned. Therefore, in the comparative example, the primary seal portion 120 is heated by the heating jig 150 only in the horizontal direction. In this case, since only the outer peripheral surface 120a of the primary seal portion 120 and its vicinity are melted, the integrated region 120b in each primary seal portion 120 is formed only near the outer peripheral surface 120a. In the comparative example, a region 120b is formed in the primary seal portion 120 in a plan view, for example, about 0.2 mm to 0.3 mm from the outer peripheral surface 120a. In this case, the distance S11 between the region 120b and the current collector 15 in the horizontal direction is about 1.2 mm to 1.3 mm. In this comparative example, it is conceivable to increase the temperature of the heating jig 150 to expand the region 120b. However, when the temperature of the heating jig 150 is raised, at least one of the positive electrode layer 16, the negative electrode layer 17, and the resin composition of the primary seal portion 120 may be adversely affected. In this case, even if the area 120b is expanded, the performance of the nickel-metal hydride battery is deteriorated.

  On the other hand, in the present embodiment, in the fifth step of welding the laminated primary seal portions 20 to each other, the primary seal portion 20 is heated from the horizontal direction by the main body portion 51 of the heating jig 50 and the heating jig 50 is heated. The primary seal portion 20 is heated from both the first protruding portion 52 and the second protruding portion 53 in the stacking direction. For this reason, compared with the comparative example in which the primary seal part 120 is simply heated from the horizontal direction, the laminated primary seal parts 20 are welded favorably. That is, compared with the case where the primary seal portion 120 is heated only from the horizontal direction, the region 20b to be welded between the laminated primary seal portions 20 can be enlarged. For example, in the primary seal portion 20 in a plan view, the region 20b is formed about 0.8 mm to 1.0 mm from the outer peripheral surface 20a. In this case, the distance S2 (see FIG. 2) between the region 20b and the current collector 15 in the horizontal direction is about 0.7 mm to 0.5 mm, and the area difference between the regions 20b and 120b in plan view is several times. Become. Therefore, in the present embodiment, the region 20b where the primary seal portions 20 are welded to each other can be easily enlarged, so that the outflow of hydrogen gas through the unwelded region in the primary seal portion 20 can be suppressed.

  In addition, the heat conducting jig 61 is in contact with the heat insulating portion 41b, and the heat conducting jig 62 is in contact with the heat insulating portion 42b. For this reason, heat conduction from the heat conduction jigs 61 and 62 to the press sections 41 and 42 is suppressed, so that the primary seal section 20 can be favorably heated from the lamination direction.

  FIG. 6 is a diagram illustrating a method for manufacturing the power storage module according to the first modification of the embodiment. In the first modification, the fifth step is performed using a heating jig having a configuration different from that of the embodiment.

  The heating jig 50A shown in FIG. 6 has a first member 54, a second member 55, and a third member 56. The first member 54 is a member that contacts the outer peripheral surface 20a of each primary seal portion 20, and has a rectangular frame shape in plan view. Each of the second member 55 and the third member 56 is located inside the first member 54 in a plan view, and has a rectangular frame shape in a plan view. The second member 55 is a member that contacts the exposed surface 20c of the primary seal portion 20 located at the lower end of the electrode stack 13. When the primary seal portion 20 is heated, the second member 55 is in contact with the heat insulating portion 41b of the press portion 41 and the exposed surface 20c, and is separated from the first member 54. The third member 56 is a member that comes into contact with the exposed surface 20d of the primary seal portion 20 located at the upper end of the electrode stack 13. When the primary seal portion 20 is heated, the third member 56 is in contact with the heat insulating portion 42b of the press portion 42 and the exposed surface 20d, and is separated from the first member 54 and the second member 55.

  Also in such a first modified example, the same operation and effect as those of the embodiment are exerted. In addition, when welding the laminated primary seal portions 20, the first member 54 heats each primary seal portion 20 from the horizontal direction, and the second member 55 heats the primary seal portion 20 from one side in the lamination direction. The third member 56 heats the primary seal portion 20 from the other side in the stacking direction. In this case, the welded region between the stacked frames can be favorably enlarged. In addition, since the first member 54, the second member 55, and the third member 56 are separated from each other, heating according to the position of the primary seal portion 20 can be easily performed.

  FIG. 7 is a diagram illustrating a method for manufacturing the power storage module according to the second modification of the embodiment. In the second modification, the fifth step is performed using a heating jig different from the embodiment and the first modification and a heat conduction jig.

  The heating jig 50B shown in FIG. 7 has a main body 51A. The main body 51A has the same shape as the main body 51 of the embodiment. The heating jig 50B is not provided with the first protrusion 52 and the second protrusion 53 (see FIG. 4B) provided on the heating jig 50 of the embodiment. Each of the heat conducting jigs 61 and 62 is a member that conducts heat from the heating jig 50B, and has a substantially rectangular frame shape in plan view. From the viewpoint of suppressing metal diffusion to the primary seal portion 20, each of the heat conduction jigs 61 and 62 is, for example, a member made of aluminum or a metal member coated with aluminum. The heat conducting jig 61 is a member that contacts the heating jig 50B and the exposed surface 20c of the primary seal portion 20 located at the lower end of the electrode stack 13. The heat conduction jig 62 is a member that contacts the heating jig 50 </ b> B and the exposed surface 20 d of the primary seal portion 20 located at the upper end of the electrode stack 13.

  When the primary seal portions 20 stacked in the second modification are welded to each other, first, the heat conductive jig 61 contacts the exposed surface 20c, and the heat conductive jig 62 contacts the exposed surface 20d. Subsequently, the main body portion 51A of the heating jig 50B contacts the outer peripheral surface 20a of each primary seal portion 20 and the heat conduction jigs 61 and 62. Thereby, the primary seal portion 20 is heated from the horizontal direction by the heating jig 50B. At the same time, the heat conductive jig 61 contacting both the exposed surface 20c and the heating jig 50B and the heat conductive jig 62 contacting both the exposed surface 20d and the heating jig 50B are primary sealed from the laminating direction. The part 20 is heated. Therefore, also in the second modified example, the same operation and effect as those of the above-described embodiment and the first modified example can be obtained. In addition, the heat conducting jig 61 is in contact with the heat insulating portion 41b, and the heat conducting jig 62 is in contact with the heat insulating portion 42b. For this reason, since heat conduction from the heat conduction jigs 61 and 62 to the press parts 41 and 42 is suppressed, the primary seal part 20 can be favorably heated from the lamination direction.

  The power storage module and the method for manufacturing the same according to the present invention are not limited to the above-described embodiment and the above-described modified examples, and various other modifications are possible. For example, the above embodiment and the above modified examples may be appropriately combined. For example, the first modification and the second modification may be combined. In this case, the second member contacts the exposed surface of the primary seal portion located at the lower end of the electrode laminate, and the heat conduction jig contacts the exposed surface of the primary seal portion located at the upper end of the electrode laminate. Is also good. Alternatively, the heat conductive jig contacts the exposed surface of the primary seal located at the lower end of the electrode stack, and the third member contacts the exposed surface of the primary seal located at the upper end of the electrode stack. Good.

  In the above-described embodiment and the above-described modified example, the primary seal portion covers a part of the peripheral portion of the current collector, but is not limited thereto. The primary seal may cover the entire edge of the current collector.

  In the above embodiment, the heating jig has the first protrusion and the second protrusion, but is not limited to this. The heating jig may have a main body and one of the first protrusion and the second protrusion. Even in this case, since the primary seal portion is heated not only in the horizontal direction but also in the lamination direction, the welded area can be more easily expanded than in the comparative example. When the heating jig has one of the first protrusion and the second protrusion, the sizes of the pair of press parts in plan view may be different from each other. For example, when the heating jig does not have the second projecting portion, the edge of the press portion that contacts the upper end of the electrode laminate may be aligned with the outer peripheral edge of the primary seal portion, or may be located outside the outer peripheral edge. May be located.

  The heating jig of the first modification includes the second member and the third member in addition to the first member, but is not limited thereto. For example, the heating jig may include a first member and one of the second member and the third member. Even in this case, since the primary seal portion is heated not only in the horizontal direction but also in the lamination direction, the welded area can be more easily expanded than in the comparative example.

  In the second modification, two heat conducting jigs are disclosed, but the present invention is not limited to this. For example, only one of the heat conducting jigs may be used. Even in this case, since the primary seal portion is heated not only in the horizontal direction but also in the lamination direction, the welded area can be more easily expanded than in the comparative example.

  DESCRIPTION OF SYMBOLS 1 ... Electric storage apparatus, 2 ... Electric storage module, 11 ... Bipolar electrode, 12 ... Separator, 13 ... Electrode laminated body, 14 ... Resin part, 15 ... Current collector, 15a ... Plate surface, 15b ... Plate surface, 15c ... Peripheral part , 16: positive electrode layer, 17: negative electrode layer, 20: primary seal portion (frame), 20a: outer peripheral surface, 20b: region, 20c: exposed surface, 20d: exposed surface, 21: secondary seal portion, 40: pressing Jigs, 50, 50A, 50B ... heating jigs, 61, 62 ... heat conduction jigs.

Claims (5)

Preparing a current collector having a pair of plate surfaces,
Forming a positive electrode layer on one of the pair of plate surfaces,
Forming a negative electrode layer on the other surface of the pair of plate surfaces;
Forming a frame that covers at least a part of a peripheral portion of the current collector;
Along the stacking direction intersecting the extending direction in which the pair of plate surfaces extend, stacking the current collector provided with the frame via a separator,
Welding the stacked frame bodies together,
With
In the step of welding the stacked frames, the frames are heated from the extending direction, and the frames are heated from at least one of the stacking directions.
Manufacturing method of power storage module.   The method according to claim 1, wherein, in the step of welding the frames, the frames are heated from the extending direction and the frames are heated from both the laminating directions. In the step of welding the frames, the frames are heated by a heating jig having a first member and a second member,
When welding the laminated frames,
The first member heats the frame from the extending direction,
3. The method according to claim 1, wherein the second member heats the frame from one side in the stacking direction. 4.   The method according to claim 3, wherein the first member and the second member are separated from each other. In the step of welding the frames, the frames are heated by a heating jig and a heat conduction jig,
When welding the laminated frames,
The heating jig heats the frame from the extending direction,
3. The power storage device according to claim 1, wherein the heat conductive jig contacts both the exposed surface of the frame positioned at one end in the stacking direction, which intersects with the stacking direction, and the heating jig. 4. Module manufacturing method.

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