JP2019216073A - Manufacturing method for power storage device and power storage device - Google Patents

Abstract

To provide a manufacturing method for a power storage device, by which uniform restraining load can be applied to a power storage module while increases of body size and weight are avoided, and to provide a power storage device.SOLUTION: A manufacturing method for a power storage device 1 comprises: an arrangement step P2 in which one or a plurality of power storage modules 4, each of which is composed including an electrode stack 11 of bipolar electrodes 14, are sandwiched between a pair of restraining plates 8 in the staking direction of the electrode stack 11; and a restraining step P3 in which edge parts of the pair of restraining plates 8 are fastened together by means of a fastening bolt 9 and a nut 10 and restraining load in the stacking direction is thereby applied to the power storage modules 4. In the arrangement step P2, the restraining plate 8 having one surface 8b provided with a curved surface S4 curved convexly is disposed such that this one surface 8b is oriented toward the power storage module 4. In the restraining step P3, the one surface 8b of the restraining plate 8 is made flat by the fastening of the fastening bolt 9 and the nut 10.SELECTED DRAWING: Figure 5

Description

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

  As one type of power storage device, a bipolar power storage device including a stacked body in which a plurality of bipolar electrodes are stacked is known. As such a power storage device, for example, there is an assembled battery described in Patent Document 1. This conventional power storage device includes a power storage module in which a stacked body of bipolar electrodes is sealed with a seal portion. In the power storage module, constraint plates are respectively disposed at both ends of the bipolar electrode in the stacking direction. The constraint plates are fastened by fastening members. Thereby, a predetermined restraining load is applied to the power storage module, and the separation between the bipolar electrodes is suppressed.

JP 2007-122977 A

  In the above-described bipolar power storage device, it is conceivable that the area of the restraint surface (the end face in the stacking direction of the bipolar electrodes) of the power storage module by the restraint plate becomes relatively large. For this reason, when a restraining load is applied to the power storage module via the restraint plate, a difference may occur in the restraining load applied to the power storage module between a portion near and far from the fastening position with the fastening member. In addition, in order to suppress the difference in the restraint load, a method of increasing rigidity by increasing the thickness of the restraint plate can be considered. However, this method may increase the size of the power storage device and increase the weight of the power storage device. There is.

  SUMMARY An advantage of some aspects of the invention is to provide a power storage device manufacturing method and a power storage device that can apply a uniform restraining load to a power storage module while avoiding an increase in physique and weight. Aim.

  A method for manufacturing a power storage device according to one aspect of the present invention includes an arrangement step of sandwiching one or a plurality of power storage modules including a stacked body of bipolar electrodes in a stacking direction of the stacked body with a pair of constraint plates; A restraining step of fastening the edges of the restraining plates to each other with a fastening member, and applying a restraining load in the stacking direction to the power storage module, wherein the disposing step has one surface provided with a convexly curved surface. The restraining plate is arranged so that the one surface faces the power storage module, and in the restraining step, one surface of the restraining plate is flattened by fastening a fastening member.

  In this method for manufacturing a power storage device, a restraining plate having one surface provided with a curved surface that is curved in a convex shape is used, and the restraining plate is arranged so that the one surface faces the power storage module in the arranging step. Then, in the restraining step following the disposing step, one surface of the restraining plate is flattened by the fastening force of the fastening member. In a portion where the curved surface is flattened, the constraint load transmitted to the power storage module via the constraint plate can be locally increased as compared with other portions. Therefore, in this method for manufacturing a power storage device, the difference in the restraint load due to the distance from the fastening position between the restraining plate and the fastening member can be reduced, and a uniform restraining load can be applied to the power storage module. Further, according to the method of manufacturing a power storage device, the thickness of the restraint plate does not become excessively thick, so that an increase in the size and weight of the power storage device can be avoided.

  The power storage device according to one aspect of the present invention includes one or a plurality of power storage modules including a stacked body of bipolar electrodes, a pair of constraint plates sandwiching the power storage module in the stacking direction of the stacked body, and a pair of constraint plates. And a fastening member that applies a restraining load in the stacking direction to the power storage module, and a pair of restraining plates have one surface facing the power storage module side when the fastening by the fastening member is released. The surface is deformed from a flat surface to a surface provided with a curved surface that is convexly curved.

  In this power storage device, in a state where the restraint plate is fastened to the power storage module by the fastening member, the restraint load transmitted from the portion corresponding to the curved surface to the power storage module via the restraint plate is locally compared with the restraint load from other portions. Can be increased. Therefore, in this power storage device, the difference in the restraint load due to the distance from the fastening position between the restraining plate and the fastening member can be reduced, and a uniform restraining load can be applied to the power storage module. Further, according to this power storage device, since the thickness of the restraint plate does not become excessively large, an increase in the size and weight of the power storage device can be avoided.

  Further, the other surface of the restraint plate may be a flat surface. In this case, the rigidity of the restraint plate can be sufficiently ensured while realizing the deformation of the curved surface described above.

  Further, the other surface of the restraint plate may be provided with a curved surface that is concavely curved following the one surface. According to such a configuration, it is possible to suppress an increase in the constraint plate. Further, the production of the restraint plate by press working or the like becomes easy.

  Further, the restraining plate has a convex portion that forms a curved surface that curves in a convex shape, and a main body portion that forms the remaining portion, the convex portion is made of resin, and the main body portion is made of metal. Is also good. In this case, the deformation of the curved surface can be easily realized. In addition, since the protrusion is made of resin, the degree of curvature of the curved surface can be easily adjusted according to the number of stacked power storage modules of the power storage device. For example, in a power storage device with a small number of stacked power storage modules (for example, one), the degree of curvature of the curved surface is reduced, while in a power storage device with a large number of stacked power storage modules (for example, ten), the degree of curvature of the curved surface is increased. Such an adjustment is required. By realizing such adjustment of the degree of curvature by a change in the shape of the convex portion, which is a resin, the main body of the restraint plate can be shared between the power storage devices.

  In addition, the protrusion may have an electrical insulating property. In this case, the convex portion also serves as an insulating member between the power storage module and the main body, thereby simplifying the configuration of the power storage device.

  In addition, the restraint plate may include a convex portion that forms a curved surface that curves in a convex shape, and a main body portion that forms the remaining portion, and the convex portion and the main body portion may be integrally formed of metal. In this case, the configuration of the restraint plate can be simplified, and an increase in the number of parts can be avoided.

  Advantageous Effects of Invention According to the present invention, a uniform restraining load can be applied to a power storage module while avoiding an increase in physique and weight.

FIG. 3 is a schematic cross-sectional view illustrating one embodiment of a power storage device. FIG. 3 is a schematic sectional view illustrating an internal configuration of the power storage module. FIG. 9 is a diagram illustrating an example of a simulation result of a deformation amount of a restraint plate in a power storage device. 4 is a flowchart illustrating an embodiment of a method for manufacturing a power storage device. FIG. 2 is a schematic cross-sectional view illustrating a manufacturing process of the power storage device illustrated in FIG. 1. FIG. 13 is a schematic cross-sectional view illustrating a power storage device according to a first modification. FIG. 7 is a schematic cross-sectional view illustrating a manufacturing process of the power storage device illustrated in FIG. 6. FIG. 13 is a schematic cross-sectional view illustrating a power storage device according to a second modification. FIG. 9 is a schematic cross-sectional view illustrating a manufacturing process of the power storage device illustrated in FIG. 8.

  Hereinafter, preferred embodiments of a method for manufacturing a power storage device and a power storage device according to one aspect of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to these examples, but is indicated by the appended claims, and is intended to include all modifications within the meaning and scope equivalent to the appended claims. In the following description, the same elements will be denoted by the same reference symbols in the description of the drawings, without redundant description.

  FIG. 1 is a schematic cross-sectional view illustrating one embodiment of a power storage device. The power storage device 1 illustrated in FIG. 1 is a device used as a battery of various vehicles such as a forklift, a hybrid vehicle, and an electric vehicle. The power storage device 1 includes a power storage module stack 2 in which a plurality of power storage modules 4 are stacked, and a restraint unit 3 that applies a restraining load to the power storage module stack 2.

  The power storage module laminate 2 includes a plurality of (three in the present embodiment) power storage modules 4 and a plurality of conductive plates 5 arranged between the plurality of power storage modules 4. The power storage module 4 is a bipolar power storage module including a plurality of bipolar electrodes 14 (see FIG. 2 described later), and has a rectangular shape when viewed from the stacking direction. The power storage module 4 is, for example, a secondary battery such as a nickel hydrogen secondary battery or a lithium ion secondary battery, or an electric double layer capacitor. In the following description, a nickel-metal hydride secondary battery will be exemplified.

  A plurality of power storage modules 4 adjacent in the stacking direction are electrically connected via a conductive plate 5. The conductive plates 5 are also arranged outside the power storage modules 4 located at the stacking ends of the power storage module laminate 2. The conductive plates 5 at these stacked ends function as current collecting plates 25 of the power storage module stack 2. A positive electrode terminal 6 is connected to the conductive plate 5 disposed outside the power storage module 4 located at one of the lamination ends. Further, a negative electrode terminal 7 is connected to the conductive plate 5 disposed outside the power storage module 4 located at the other lamination end. The positive electrode terminal 6 and the negative electrode terminal 7 are drawn out, for example, from the edge of the conductive plate 5 in a direction crossing the laminating direction. The power storage device 1 is charged and discharged by the positive terminal 6 and the negative terminal 7.

  Inside each conductive plate 5, a plurality of flow paths 5a for circulating a refrigerant such as air are provided. Each flow path 5a extends parallel to each other, for example, in a direction orthogonal to the stacking direction and the direction in which the positive electrode terminal 6 and the negative electrode terminal 7 are drawn out. By circulating a coolant through these flow paths 5a, the conductive plate 5 functions as a connecting member for electrically connecting the plurality of power storage modules 4, and a radiator plate that radiates heat generated in the power storage modules 4. It also has the function of In the example of FIG. 1, the area of the conductive plate 5 as viewed from the stacking direction is smaller than the area of the power storage module 4, but from the viewpoint of improving heat dissipation, the area of the conductive plate 5 is smaller than the area of the power storage module 4. And may be larger than the area of the power storage module 4.

  The restraint part 3 includes a pair of restraint plates 8 sandwiching the power storage module laminate 2 in the stacking direction, a plurality of fastening bolts (fastening members) 9 and a plurality of nuts (fastening members) 10 for fastening the pair of restraining plates 8 to each other. It is comprised including. The restraint plate 8 is a rectangular plate having an area slightly larger than the area of the power storage module 4 and the conductive plate 5 when viewed from the stacking direction. The restraint plate 8 has one surface 8b and the other surface 8c facing each other in the stacking direction. One surface 8b faces the power storage module laminate 2 side, and the other surface 8c faces the opposite side to the power storage module laminate 2 side. In the fastened state of restraint plate 8, the central portion of one surface 8b is in contact with conductive plate 5 disposed outside power storage module 4 located at the stacking end of power storage module laminate 2, and the central portion is flat. Surface. In the fastening state of the restraining plate 8, a central portion of the other surface 8c is a curved surface S1 that is convexly curved. The entire surface of the other surface 8c may be the curved surface S1, or only a part of the other surface 8c may be the curved surface S1. The detailed configuration of the restraint plate 8 will be described later.

  A plurality of insertion holes 8 a is provided at an edge of the restraint plate 8 at a position outside the power storage module laminate 2. The plurality of insertion holes 8a are arranged at predetermined intervals along the peripheral edge of each restraint plate 8 as viewed from the laminating direction. Each fastening bolt 9 is passed from each through hole 8a of one restraining plate 8 toward each through hole 8a of the other restraining plate 8, and each fastening bolt 9 protrudes from each through hole 8a of the other restraining plate 8. Each of the nuts 10 is screwed to the tip of the nut. Thereby, the edges of the pair of restraint plates 8 are fastened to each other, the power storage module 4 and the conductive plate 5 are sandwiched by the pair of restraint plates 8, and are unitized as the power storage module laminate 2. Further, a constraint load is applied to the power storage module laminate 2 in the laminating direction.

  FIG. 2 is a schematic cross-sectional view illustrating the internal configuration of the power storage module 4. As shown in the figure, the power storage module 4 includes an electrode stack 11 and a sealing body 12 that seals the electrode stack 11.

  The electrode laminate 11 is configured by laminating a plurality of bipolar electrodes 14 via a separator 13. The bipolar electrode 14 is an electrode including an electrode plate 15 having a positive electrode 16 formed on one surface 15a and a negative electrode 17 formed on the other surface 15b. In the electrode stack 11, the positive electrode 16 of one bipolar electrode 14 faces the negative electrode 17 of one bipolar electrode 14 adjacent in the stacking direction with the separator 13 interposed therebetween. In the electrode stack 11, the negative electrode 17 of one bipolar electrode 14 faces the positive electrode 16 of the other bipolar electrode 14 adjacent in the stacking direction with the separator 13 interposed therebetween.

  A negative terminal electrode 18 is disposed on one of the lamination ends of the electrode laminate 11, and a positive terminal electrode 19 is disposed on the other of the lamination ends of the electrode laminate 11. The negative electrode terminal electrode 18 is constituted by an electrode plate 15 having a negative electrode 17 formed on the inner surface side (center side in the stacking direction). The positive electrode terminal electrode 19 has the positive electrode 16 formed on the inner surface side (center side in the stacking direction). It is constituted by the formed electrode plate 15. The negative electrode 17 of the negative electrode terminal electrode 18 faces the positive electrode 16 of one bipolar electrode 14 at the lamination end via the separator 13. The positive electrode 16 of the positive electrode termination electrode 19 faces the negative electrode 17 of the other bipolar electrode 14 at the lamination end via the separator 13. The electrode plate 15 of the negative terminal electrode 18 and the electrode plate 15 of the positive terminal electrode 19 are electrically connected to the conductive plate 5 (see FIG. 1) adjacent to the power storage module 4.

  The electrode plate 15 is a rectangular metal foil made of, for example, nickel. The edge 15 c of the electrode plate 15 is an uncoated area where the positive electrode active material and the negative electrode active material are not applied, and the uncoated area is buried and held in the sealing body 12. As the positive electrode active material constituting the positive electrode 16, for example, nickel hydroxide is given. The negative electrode active material constituting the negative electrode 17 includes, for example, a hydrogen storage alloy. In the present embodiment, the formation region of the negative electrode 17 on the other surface 15 b of the electrode plate 15 is slightly larger than the formation region of the positive electrode 16 on the one surface 15 a of the electrode plate 15.

  The separator 13 is formed in a sheet shape, for example. Examples of a material for forming the separator 13 include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), and a woven or nonwoven fabric made of polypropylene, methyl cellulose, or the like. Further, the separator 13 may be reinforced with a vinylidene fluoride resin compound.

  The sealing body 12 is formed in a rectangular cylindrical shape using, for example, an insulating resin. Examples of the resin material forming the sealing body 12 include polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE). The sealing body 12 is configured to surround a side surface of the electrode stack 11 formed by stacking the bipolar electrodes 14.

  The sealing body 12 includes a primary sealing body 21 provided along the edge 15 c of the electrode plate 15 of each bipolar electrode 14, and a secondary sealing body 21 provided so as to surround the entirety of the primary sealing body 21 from the outside. And the next sealing body 22. The primary sealing body 21 is formed by, for example, injection molding of a resin, and is provided continuously over all sides of the electrode plate 15 at an edge 15c (uncoated region) on the one surface 15a side of the electrode plate 15. I have. In the present embodiment, the primary sealing body 21 is provided so as to extend from the one surface 15a side to the end surface 15d side of the electrode plate 15, and is connected to the one surface 15a and the end surface 15d by, for example, welding.

  The primary sealing body 21 not only seals between the plurality of bipolar electrodes 14 adjacent in the stacking direction, but also functions as a spacer between the plurality of electrode plates 15 of the bipolar electrodes 14 adjacent in the stacking direction. Between the plurality of electrode plates 15, an internal space V defined by the thickness of a portion of the primary sealing body 21 located between the plurality of electrode plates 15 is formed. The internal space V contains an electrolytic solution (not shown) made of an alkaline solution such as an aqueous potassium hydroxide solution.

  The secondary sealing body 22 is formed by, for example, injection molding of a resin, and extends over the entire length of the electrode stack 11 in the stacking direction. The secondary sealing body 22 is welded to the outer surface of the primary sealing body 21 by, for example, heat during injection molding. In the sealed body 12, the electrolytic solution accommodated in the internal space V can pass between the primary sealed bodies 21 adjacent in the laminating direction, but at the welded portion between the primary sealed body 21 and the secondary sealed body 22. It is sealed.

  Subsequently, a detailed configuration of the above-described restraint plate 8 will be described. In power storage device 1, edges of a pair of restraint plates 8 are fastened to each other by fastening bolts 9 and nuts 10, and a restraint load is applied to power storage module laminate 2 in the stacking direction. First, the relationship between the fastening position of the constraint plate 8 and the distribution of the constraint load will be described. FIG. 3 is a diagram illustrating an example of a simulation result of the deformation amount of the restraint plate in the power storage device. The simulation result is obtained by calculating the distribution of the restraint load in the power storage device in which the power storage modules are restrained in the stacking direction by fastening the edges of the restraint plates.

  FIG. 3 illustrates a state in which the end surface of the power storage module in the stacking direction is divided into eight parts so as to include one corner (the upper right part in FIG. 3 is a corner). The constraint load applied to the end face is indicated by a contour line, and the darker the color, the smaller the constraint load. As simulation conditions, the thickness of the restraint plate was 17 mm, the separator compression ratio was 40%, and the internal pressure of the power storage module was 0 MPa. From the results shown in FIG. 3, the constraint load applied to the power storage module decreases as the distance from the fastening position (edge of the restraint plate) between the restraint plate and the fastening bolt decreases, and the edge and the center of the end face of the power storage module are reduced. It can be seen that there is a difference in the restraint load between and.

  In order to suppress such a difference in the restraint load, in the power storage device 1, as shown in FIG. 1, the restraint plate 8 is configured by a convex portion 30 and a plate-shaped main body portion 31 forming a remaining portion. Have been. The convex portion 30 is a portion that constitutes a central portion of the one surface 8 b of the restraint plate 8, and is provided on the power storage module laminate 2 side with respect to the main body portion 31. The thickness of the projection 30 is the largest at the center of the main body 31 and gradually decreases from the center to the edge. When the restraining plate 8 is fastened, a reaction force of a restraining load is applied to the protrusion 30 in the stacking direction. As a result, one surface 8b of the convex portion 30 is a flat surface in contact with the conductive plate 5, and the central portion of the opposite surface 30a opposite to the one surface 8b is convex toward the main body portion 31. It is a curved surface S2 that curves in a shape. The protrusion 30 is made of, for example, a resin material having electrical insulation. It is preferable that a material capable of maintaining a thickness against compression be used as the material of the protrusion 30. As a material of such a convex portion 30, for example, polypropylene, PPS, PPE, or the like can be given. The entire surface of the opposite surface 30a may be a curved surface S2, or a part of the opposite surface 30a may be a curved surface S2.

  The main body 31 is a rectangular plate made of a metal such as Fe or Al. In the fastened state of the restraint plate 8, the main body portion 31 is curved toward the opposite side to the power storage module laminate 2 along the curved shape of the curved surface S2 of the convex portion 30. That is, the central portion of the contact surface 31a of the main body portion 31 with the opposite surface 30a of the convex portion 30 is a curved surface S3 that curves concavely following the curved surface S2 of the opposite surface 30a, and the other surface 8c Is a curved surface S1 that curves in a convex shape following the curved surface S3 of the contact surface 31a. Note that the entire contact surface 31a may be a curved surface S3, or a part of the contact surface 31a may be a curved surface S3.

  When the fastening of the restraint plate 8 is released, the projection 30 is released from the reaction force, and the projection returns to the original shape. Thereby, the curved shape of the restraint plate 8 is reversed in the laminating direction as compared with the fastening state (see FIG. 5). That is, when the fastening of the restraint plate 8 is released, the central portion of the one surface 8b is deformed from a flat surface to a curved surface S4 that is convexly curved, and the curved surface S1 of the other surface 8c is deformed to a flat surface. In addition, the curved surface S4 of the convex portion 30 is deformed into a flat surface according to the deformation of the one surface 8b, and the main body portion 31 is changed from a curved state to a flat state following the deformation of the convex portion 30.

  A method for manufacturing the power storage device 1 having the above configuration will be described with reference to FIGS. FIG. 4 is a flowchart illustrating a method for manufacturing power storage device 1. FIG. 5 is a diagram illustrating a manufacturing process of the power storage device 1.

  First, a plurality of power storage modules 4 are stacked to form a power storage module laminate 2 (lamination step P1). Next, as shown in FIG. 5, the power storage module laminate 2 is sandwiched between the pair of restraint plates 8 in the laminating direction (arrangement step P2). In the arrangement step P2, the pair of restraint plates 8 are arranged such that the curved surface S4 of the projection 30 faces the power storage module laminate 2 side. At this time, the opposite surface 30a of the convex portion 30 is a flat surface, and the main body portion 31 is in a flat state. In the arrangement step P2, the positive electrode terminal 6 is connected to the conductive plate 5 disposed on one side in the stacking direction of the power storage module laminate 2, and the conductive plate 5 disposed on the other side in the stacking direction of the power storage module laminate 2 The negative electrode terminal 7 may be connected to 5 (see FIG. 1).

  Next, as shown in FIG. 1, the edges of the pair of restraint plates 8 are fastened by fastening bolts 9 and nuts 10 to apply a restraint load in the stacking direction to the power storage module laminate 2 (restraining step P3). . In the restraining step P3, each fastening bolt 9 is passed from each of the through holes 8a provided at the edge of one restraining plate 8 toward each of the through holes 8a provided at the edge of the other restraining plate 8, Each nut 10 is screwed to the tip of each fastening bolt 9 protruding from each insertion hole 8a of the other restraining plate 8. Thus, the edges of the pair of restraint plates 8 are fastened to each other, the power storage module 4 and the conductive plate 5 are sandwiched between the pair of restraint plates 8, and a restraint load is applied to the power storage module laminate 2 in the stacking direction. At this time, the curved surface S4 of the convex portion 30 is pressed against the power storage module laminate 2, and the curved surface S4 is flattened by the fastening force (restraint load) by the fastening bolt 9 and the nut 10. Thereby, the curved shape of the constraint plate 8 is reversed in the laminating direction as compared with the constraint plate 8 in the arrangement process P2. That is, the central portion of the other surface 8c is deformed from a flat surface to a curved surface S1 that is convexly curved. In addition, the central portion of the opposite surface 30a of the convex portion 30 is deformed from a flat surface to a convex curved surface S2 according to the deformation of the curved surface S4. The main body 31 deforms from a flat state to a curved state following the deformation of the projection 30. That is, the central portion of the contact surface 31a is deformed from a flat surface to a curved surface S3 that concavely curves following the curved surface S2 of the opposite surface 30a, and the central portion of the other surface 8c is changed from the flat surface to the contact surface S3. Following the curved surface S3 of the contact surface 31a, the contact surface 31a is deformed into a curved surface S1 that is convexly curved.

  The method for manufacturing the power storage device 1 and the effects obtained by the power storage device 1 described above will be described. In the method for manufacturing power storage device 1, as described above, constraint plate 8 having one surface 8 b provided with curved surface S <b> 4 that is curved in a convex shape is used, and one surface 8 b is positioned on power storage module laminate 2 side in placement step P <b> 2. (See FIG. 5). Then, in a restraining process P3 following the disposing process P2, the curved surface S4 of the one surface 8b of the restraining plate 8 is flattened by the fastening force of the fastening bolt 9 and the nut 10 (see FIG. 1). In a portion where the curved surface S4 is flat, the constraint load transmitted to the power storage module laminate 2 via the constraint plate 8 can be locally increased as compared with other portions. Therefore, in the method of manufacturing the power storage device 1, the difference in the restraint load due to the distance from the fastening position (the edge of the restraint plate 8) between the restraint plate 8 and the fastening bolt 9 and the nut 10 can be reduced. A uniform restraining load can be applied. Further, according to the method for manufacturing power storage device 1, since the thickness of restraint plate 8 does not become excessively large, an increase in the size and weight of power storage device 1 can be avoided.

  Further, in power storage device 1, in a state where restraining plate 8 is fastened to power storage module laminate 2 by fastening bolts 9 and nuts 10, a portion corresponding to curved surface S <b> 4 is connected to power storage module laminate 2 via restraining plate 8. The transmitted constraint load can be locally increased as compared to the constraint load from other parts. Therefore, in power storage device 1, the difference in the restraint load due to the distance from the fastening position of restraint plate 8 to fastening bolt 9 and nut 10 can be reduced, and a uniform restraint load can be applied to power storage module laminate 2. Further, according to this power storage device 1, since the thickness of restraint plate 8 does not become excessively large, it is possible to avoid an increase in the size and weight of power storage device 1.

  Further, the other surface 8c of the constraint plate 8 may be a flat surface. In this case, the rigidity of the restraint plate 8 can be sufficiently secured while realizing the deformation of the curved surface S4 described above.

  Further, the protrusion 30 may be made of resin, and the main body 31 may be made of metal. In this case, the deformation of the curved surface S4 can be easily realized. In addition, since the protrusion 30 is made of resin, the degree of curvature of the curved surface S4 can be easily adjusted according to the number of stacked power storage module laminates 2 of the power storage device 1. For example, in the power storage device 1 in which the number of stacked power storage module stacked bodies 2 is small (for example, one), the degree of curvature of the curved surface S4 is reduced, whereas in the power storage device in which the number of stacked power storage modules is large (for example, ten), the curved surface S4 It is necessary to make an adjustment to increase the degree of curvature. By realizing such adjustment of the degree of curvature by changing the shape of the convex portion 30 made of resin, the main body 31 of the restraint plate 8 can be shared between the power storage devices 1.

  In addition, the protrusion 30 may have electrical insulation. In this case, the configuration of the power storage device 1 can be simplified by using the protrusion 30 as an insulating member between the power storage module laminate 2 and the main body 31.

(First modification)
FIG. 6 is a schematic sectional view showing a power storage device 1A according to a first modification. FIG. 7 is a schematic cross-sectional view showing an arrangement step P2 of power storage device 1A shown in FIG. The difference between the above embodiment and the present modification lies in the configuration of the restraint plate. In the constraint plate 8A according to the present modification, the projection 30 and the main body 31 are integrally formed of metal. As the material of the constraint plate 8A, for example, the same material as that of the main body 31 of the above embodiment is selected. In this modification, a film F having electrical insulation is provided between one surface 8b of the constraint plate 8A and the conductive plate 5. The film F electrically insulates between the constraint plate 8A and the conductive plate 5.

  As shown in FIG. 6, the thickness of the restraint plate 8A is the thickest at the central portion, and gradually decreases from the central portion toward the edge. In the fastening state of the constraint plate 8A, a reaction force of a constraint load is applied to the constraint plate 8A in the stacking direction. As a result, the one surface 8b is in contact with the film F and is flat, and the central portion of the other surface 8c is a curved surface S1 that is convexly curved. When the fastening of the constraint plate 8A is released, the constraint plate 8A is released from the reaction force, and the constraint plate 8A returns to its original shape. As a result, the curved shape of the constraint plate 8A is reversed in the stacking direction as compared with the fastening state (see FIG. 7). That is, when the fastening of the restraint plate 8A is released, the central portion of the one surface 8b is deformed from a flat surface to a curved surface S4 that is convexly curved, and the curved surface S1 of the other surface 8c is deformed to a flat surface.

  In the arrangement step P2 of the power storage device 1A, as shown in FIG. 7, the pair of restraint plates 8A are disposed such that the curved surface S4 of the one surface 8b faces the power storage module laminate 2 side. Thereafter, in the restraining step P3, the curved surface S4 is pressed against the power storage module laminate 2 and is flattened by the fastening force (restraint load) by the fastening bolt 9 and the nut 10. Thereby, the curved shape of the constraint plate 8A is reversed in the stacking direction as compared with the constraint plate 8A in the arrangement step P2. That is, the central portion of the other surface 8c is deformed from a flat surface to a curved surface S1 that is convexly curved. Even with such a configuration, the same effects as in the above embodiment can be obtained. Further, since the projection 30 and the main body 31 are integrally formed, the configuration of the restraint plate 8A can be simplified, and an increase in the number of parts can be avoided.

(Second modification)
FIG. 8 is a schematic sectional view showing a power storage device 1B according to a second modification. FIG. 9 is a schematic cross-sectional view showing an arrangement step P2 of power storage device 1B shown in FIG. The difference between the above embodiment and the present modification lies in the configuration of the restraint plate. In the present modification, as shown in FIG. 8, the restraint plate 8B does not have the convex portion 30, but has only the main body portion 31 forming the one surface 8b and the other surface 8c. In this modification, a film F having electrical insulation is provided between one surface 8b of the constraint plate 8B and the conductive plate 5. The film F electrically insulates between the constraint plate 8B and the conductive plate 5.

  As shown in FIG. 8, the constraint plate 8B (the main body 31) has a uniform thickness and is in a flat state. In the fastening state of the constraint plate 8B, a reaction force of the constraint load is applied to the constraint plate 8B in the stacking direction. Thereby, one surface 8b is in contact with the film F and is flat, and the other surface 8c is also flat following the one surface 8b. When the fastening of the restraint plate 8B is released, the restraint plate 8B is released from the reaction force, and the restraint plate 8B returns to its original shape (see FIG. 9). That is, when the fastening of the restraint plate 8B is released, the central portion of the one surface 8b is deformed from a flat surface to a curved surface S4 that curves convexly, and the central portion of the other surface 8c follows the curved surface S4 from the flat surface. Then, it is deformed into a curved surface S5 that is concavely curved.

  In the arrangement step P2 of the power storage device 1B, as shown in FIG. 9, the pair of restraint plates 8B are disposed such that the curved surface S4 of the one surface 8b faces the power storage module laminate 2 side. Thereafter, in the restraining step P3, the curved surface S4 is pressed against the power storage module laminate 2 and is flattened by the fastening force (restraint load) by the fastening bolt 9 and the nut 10. Thereby, the curved surface S5 of the other surface 8c flattens following the deformation of the one surface 8b. Even with such a configuration, the same effects as in the above embodiment can be obtained. Further, according to such a configuration, it is possible to suppress an increase in the constraint plate 8B. Further, the production of the constraint plate 8B by press working or the like becomes easy.

  The present invention is not limited to the embodiment described above, and various other modifications are possible. For example, the above-described embodiments and the respective modifications may be combined with each other according to necessary purposes and effects. Further, in the above-described embodiment, the protruding portion is made of a material having electrical insulation. However, if electrical insulation between the main body and the conductive plate can be ensured by other members, the electrical insulation may be reduced. It may be made of a material not having. Further, in the above-described embodiment and each of the modified examples, in the disposing step, a curved surface that is convexly curved is provided on one surface of the pair of restraint plates, but the curved surface is provided only on one surface of one of the restraint plates. May be provided.

  1, 1A, 1B ... power storage device, 3 ... restraint part, 4 ... power storage module, 8, 8A, 8B ... restraint plate, 8b ... one surface, 8c ... other surface, 9 ... fastening bolt (fastening member), 10 ... nut (Fastening member), 11: electrode laminate (laminate), 13: separator, 14: bipolar electrode, 16: positive electrode, 17: negative electrode, 25: current collector plate, 30: convex portion, 31: main body, S1, S2, S3, S4, S5: curved surface.

Claims (12)

An arrangement step of sandwiching one or a plurality of power storage modules including a bipolar electrode laminate in a stacking direction of the laminate by a pair of constraint plates,
A restraining step of fastening the edges of the pair of restraining plates to each other with a fastening member, and applying a restraining load in the stacking direction to the power storage module;
In the arranging step, the restraining plate having one surface provided with a curved surface that is convexly curved is arranged such that the one surface faces the power storage module side,
The method of manufacturing a power storage device, wherein in the restraining step, the one surface of the restraint plate is flattened by fastening the fastening member.   The method according to claim 1, wherein the other surface of the restraint plate is a flat surface.   The method for manufacturing a power storage device according to claim 1, wherein a curved surface that is concavely curved following the one surface is provided on the other surface of the restraint plate. The restraint plate has a convex portion forming a curved surface that curves in the convex shape, and a main body portion forming a remaining portion,
The method for manufacturing a power storage device according to any one of claims 1 to 3, wherein the protrusion is made of a resin, and the main body is made of a metal.   The method for manufacturing a power storage device according to claim 4, wherein the protrusion has electrical insulation properties. The restraint plate has a convex portion forming a curved surface that curves in the convex shape, and a main body portion forming a remaining portion,
The method for manufacturing a power storage device according to any one of claims 1 to 3, wherein the protrusion and the main body are integrally formed of metal. One or more power storage modules including a stacked body of bipolar electrodes,
A pair of restraint plates sandwiching the power storage module in the stacking direction of the stack,
A fastening member that fastens edges of the pair of restraint plates to each other and applies a restraint load in the stacking direction to the power storage module;
The power storage device, wherein when the fastening by the fastening member is released, one surface facing the power storage module is deformed from a flat surface to a surface provided with a curved surface that is convexly curved.   The power storage device according to claim 7, wherein the other surface of the restraint plate is a flat surface.   The power storage device according to claim 7, wherein a curved surface that is concavely curved following the one surface is provided on the other surface of the restraint plate. The restraint plate has a convex portion forming a curved surface that curves in the convex shape, and a main body portion forming a remaining portion,
The power storage device according to any one of claims 7 to 9, wherein the protrusion is made of a resin, and the main body is made of a metal.   The power storage device according to claim 10, wherein the protrusion has electric insulation. The restraint plate has a convex portion forming a curved surface that curves in the convex shape, and a main body portion forming a remaining portion,
The power storage device according to any one of claims 7 to 9, wherein the protrusion and the main body are integrally formed of metal.