JP2018049794A - Power storage device, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a power storage device which enables the enhancement of a sealing performance; and a method for manufacturing the power storage device.SOLUTION: A power storage device 10 comprises: a plurality of bipolar electrodes 12 stacked with a separator 14 interposed therebetween, and each having a positive electrode layer 18 provided on one face 16a of a current collector 16, and a negative electrode layer 20 provided on the other face 16b of the current collector; spacers 60 made of rubber-based resin for holding a distance between the current collectors of bipolar electrodes adjacent to each other; and a case 65 made of a resin and disposed so as to surround the spacers from outside. The spacers are disposed along the peripheral edge of the current collector at given intervals inside the peripheral edge. The case holds the peripheral edges of the current collectors.SELECTED DRAWING: Figure 1

Description

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

  A power storage device (bipolar battery) comprising a laminate in which a bipolar electrode having a positive electrode formed on one surface of a current collector and a negative electrode formed on the other surface is laminated in one direction via a separator holding an electrolyte Are known. These power storage devices are stacked via an electrolyte layer to form a power generation element. For example, Patent Document 1 discloses a power storage device (bipolar battery) that includes a separator that holds an electrolyte layer, and a sealing resin that is molded and arranged on the outer periphery of a portion that holds the electrolyte of the separator. Yes. According to the power storage device of Patent Document 1, it is possible to prevent a liquid junction (short circuit) due to leakage of the electrolytic solution, and to improve reliability.

JP 2011-151016 A

  However, since the power storage device is used by being mounted on a vehicle or the like, further improvement in sealing performance is required.

  An object of this invention is to provide the electrical storage apparatus which can improve sealing performance, and the manufacturing method of an electrical storage apparatus.

  A power storage device according to the present invention is a power storage device in which a plurality of bipolar electrodes each having a positive electrode layer provided on one surface of a current collector and a negative electrode layer provided on the other surface of the current collector are stacked via a separator. And a spacer made of a rubber-based resin that keeps a distance between current collectors of adjacent bipolar electrodes, and a case made of a resin arranged so as to surround the outside of the spacer. Along the periphery of the body, the case is disposed at a predetermined interval inside the periphery, and the case holds the periphery of the plurality of current collectors.

  In the power storage device having this configuration, the spacer made of a rubber-based resin that keeps the distance between the current collectors of the adjacent bipolar electrodes is arranged along the periphery of the current collector. It is possible to prevent the electrolyte from leaking out. Furthermore, in the power storage device with this configuration, the case for holding the peripheral edge of the current collector is disposed outside the spacer, so even if the electrolyte leaks through the spacer, The leakage of the electrolyte can be prevented by the arranged case. As a result, the sealing performance can be improved.

  The outer peripheral surface of the spacer and the inner peripheral surface of the case may have an uneven shape that fits together. Thereby, a spacer and a case can be integrated more firmly.

  The power storage device may be configured as a nickel hydride secondary battery. Also in the nickel-hydrogen secondary battery configured in this way, the sealing performance can be improved.

  According to the method of manufacturing the power storage device of the present invention, a plurality of bipolar electrodes each having a positive electrode layer provided on one surface of a current collector and a negative electrode layer provided on the other surface of the current collector are stacked via a separator. A method of manufacturing a power storage device, wherein a first step of laminating a spacer made of a rubber-based resin along a peripheral edge of a current collector while maintaining a distance between current collectors of adjacent bipolar electrodes And a second step of forming a primary product integrated by hot pressing a plurality of bipolar electrodes stacked via a spacer in the stacking direction, and surrounding the outer side of the spacer in the primary product and the peripheral edge of the current collector A third step of forming a secondary product by forming a case made of resin that holds the secondary material by insert molding, and a restraint in which the secondary product is arranged at both ends in the lamination direction of the bipolar electrode By comprising a fourth step of fastening at pressurized condition, the.

  In the above method for manufacturing a power storage device, a stacked body in which bipolar electrodes are stacked through a separator is integrated by a spacer. When integrating a non-integrated laminate with a resin case, it takes time to fix each part of the laminate with a jig, etc., but this labor is omitted in this manufacturing method. can do. Further, in the power storage device manufactured by this manufacturing method, a spacer made of a rubber-based resin that keeps an interval between current collectors of adjacent bipolar electrodes is disposed along the periphery of the current collector. Therefore, it is possible to prevent the electrolyte from leaking outside the current collector. Furthermore, in the power storage device with this configuration, the case for holding the peripheral edge of the current collector is disposed outside the spacer, so even if the electrolyte leaks through the spacer, The leakage of the electrolyte can be prevented by the arranged case. As a result, the sealing performance can be improved.

  According to the present invention, the sealing performance can be improved.

It is sectional drawing which shows typically the electrical storage apparatus which concerns on one Embodiment. It is sectional drawing which shows an example of a manufacturing method typically. It is sectional drawing which shows an example of a manufacturing method typically. It is sectional drawing which shows typically the electrical storage apparatus which concerns on a modification.

  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 reference numerals are used for the same or equivalent elements, and redundant descriptions are omitted. 1 to 4 show an XYZ orthogonal coordinate system.

  A power storage device 10 shown in FIG. 1 is a nickel hydride secondary battery mounted on a vehicle such as a forklift, a hybrid vehicle, or an electric vehicle. The power storage device 10 includes a plurality of bipolar electrodes 12, a positive electrode termination electrode 30, a positive electrode terminal member 35, a negative electrode termination electrode 40, a negative electrode terminal member 45, a pair of restraining bodies 50 and 50, a spacer 60, a case, 65.

  The plurality of bipolar electrodes 12 are stacked in series via the separator 14. Each of the bipolar electrodes 12 includes a current collector 16 having one surface 16a and the other surface 16b opposite to the one surface 16a, a positive electrode layer 18 provided on one surface 16a, and the other surface 16b. A negative electrode layer 20 provided on the surface 16b. The positive electrode layer 18 and the negative electrode layer 20 extend along a plane (for example, an XY plane) that intersects the stacking direction of the plurality of bipolar electrodes 12 (hereinafter also referred to as the Z-axis direction).

  The separator 14 is disposed between the bipolar electrodes 12 adjacent to each other, between the positive electrode termination electrode 30 and the bipolar electrode 12, and between the bipolar electrode 12 and the negative electrode termination electrode 40. For example, the separator 14 is formed in a rectangular sheet shape that is a shape viewed from the Z-axis direction. The separator 14 is a porous film or a nonwoven fabric, for example. The separator 14 can permeate the electrolytic solution. Examples of the material of the separator 14 include polyolefins such as polyethylene and polypropylene, and polyimide. As the electrolytic solution, for example, an alkaline solution such as an aqueous potassium hydroxide solution can be used.

The current collector 16 is, for example, a metal foil made of nickel, stainless steel, a Ni-plated steel plate, or the like, as viewed from the Z-axis direction. The thickness of the current collector 16 is, for example, 1 to 50 μm. The positive electrode layer 18 includes a positive electrode active material. The positive electrode active material is, for example, nickel hydroxide (Ni (OH) ₂ ) particles. The negative electrode layer 20 includes a negative electrode active material. The negative electrode active material is, for example, hydrogen storage alloy particles. The current collector 16 may be a conductive resin.

  The positive electrode termination electrode 30 is disposed via the separator 14 at one end in the Z-axis direction of the plurality of bipolar electrodes 12 (bipolar electrode group). That is, the positive electrode termination electrode 30 is disposed on the outermost side of the plurality of bipolar electrodes 12 in the Z-axis direction. For example, the positive electrode termination electrode 30 has a rectangular shape when viewed from the Z-axis direction, and a current collector 31 that is a metal foil made of nickel, stainless steel, a Ni-plated steel plate, or the like, and one of the current collectors 31 And a positive electrode layer 33 provided on the surface 31a. The positive electrode layer 33 extends along the XY plane. The current collector 31 is thicker than the current collector 16 in the Z-axis direction. The positive electrode layer 33 has the same configuration as the positive electrode layer 18 in the bipolar electrode 12. The current collector 31 may be a conductive resin.

  The negative electrode termination electrode 40 is disposed via the separator 14 at the other end in the Z-axis direction of the plurality of bipolar electrodes 12 (bipolar electrode group). That is, the negative electrode termination electrode 40 is disposed on the outermost side of the plurality of bipolar electrodes 12 in the Z-axis direction. The negative electrode termination electrode 40 has, for example, a rectangular shape as viewed from the Z-axis direction, and a current collector 41 that is a metal foil made of nickel, stainless steel, a Ni-plated steel plate, or the like, and one of the current collectors 41 And a negative electrode layer 43 provided on the surface 41a. The negative electrode layer 43 extends along the XY plane. The current collector 41 is thicker than the current collector 16 in the Z-axis direction. The negative electrode layer 43 has the same configuration as the negative electrode layer 20 in the bipolar electrode 12. The current collector 31 may be a conductive resin.

  The positive electrode terminal member 35 is disposed between the positive electrode termination electrode 30 and the restraining body 50, and is disposed in contact with the current collector 31 in the positive electrode termination electrode 30. The positive electrode terminal member 35 has a contact portion 37 and a lead portion 39. For example, the contact portion 37 has a rectangular shape as viewed from the Z-axis direction, and is in contact with the other surface 31 b of the current collector 31 in the positive electrode termination electrode 30. The lead-out portion 39 is inserted through a through portion 65 a in the case 65 described in detail later, and is pulled out to the outside of the case 65. The lead portion 39 functions as a terminal that can charge and discharge the power storage device 10.

  The negative electrode terminal member 45 is disposed between the negative electrode termination electrode 40 and the restraining body 50, and is disposed in contact with the current collector 41 in the negative electrode termination electrode 40. The negative terminal member 45 has a contact portion 47 and a lead portion 49. For example, the contact portion 47 is rectangular when viewed from the Z-axis direction, and is in contact with the other surface 41 b of the current collector 41 in the negative electrode termination electrode 40. The lead-out portion 49 is inserted through a through portion 65 a in the case 65 described in detail later, and is pulled out to the outside of the case 65. The lead portion 49 functions as a terminal that can charge and discharge the power storage device 10.

  The spacer 60 maintains the interval between the current collectors 16 of the adjacent bipolar electrodes 12. The spacer 60 is disposed inside the peripheral edge 16 c along the peripheral edge 16 c of the current collector 16. When viewed from the Z-axis direction, the peripheral edge 16c and the spacer 60 are in a state where the end of the current collector 16 protrudes by a predetermined length.

  The spacer 60 is formed from a rubber-based resin having resistance to an electrolytic solution (potassium hydroxide). Examples of the rubber-based resin include EPDM (ethylene / propylene / diene rubber) and fluorine rubber.

  As shown in FIG. 1, the case 65 includes a plurality of bipolar electrodes 12, a separator 14, a positive electrode termination electrode 30, a negative electrode termination electrode 40, and a spacer 60 in the Z-axis direction. The end portion in the direction orthogonal to the Z-axis direction of the body 25 (the end portion that becomes the outer shape when the stacked body 25 is viewed from the Z-axis direction) is covered. In other words, the laminated body 25 is surrounded and held. The case 65 is a resin case formed in a cylindrical shape, and the case 65 is filled with an electrolytic solution.

  The case 65 is disposed so as to surround the outer peripheral surface 60 a of the spacer 60. Further, the case 65 holds the peripheral edge 16 c of the current collectors 16, the peripheral edge 31 c of the current collector 31 in the positive electrode termination electrode 30, and the peripheral edge 41 c of the current collector 41 in the negative electrode termination electrode 40. . The case 65 is made of an insulating resin that has corrosion resistance to an electrolytic solution (potassium hydroxide) and low gas permeability. Examples of the resin forming the case 65 include modified PPE (modified polyphenylene ether) and PPS (polyphenylene sulfide).

  The pair of restraining bodies 50, 50 includes, in the Z-axis direction, a laminated body 25 including a plurality of bipolar electrodes 12, a positive electrode termination electrode 30, and a negative electrode termination electrode 40, a positive electrode termination electrode 30, and a negative electrode The terminal electrode 40 is sandwiched. Further, the pair of restraining bodies 50, 50 sandwich the case 65 in addition to the stacked body 25. The pair of restraining bodies 50, 50 are formed of SUS (stainless steel). In this case, an insulating sheet may be disposed between the restraining body 50 and the positive electrode terminal member 35 and between the restraining body 50 and the negative electrode terminal member 45. In addition, a pair of restraint bodies 50 and 50 may be formed with resin. The insulating sheet or resin material may have resistance to potassium hydroxide.

  The pair of restraining bodies 50, 50 are provided with through holes 50a for penetrating bolts B extending in the Z-axis direction. The through hole 50a is disposed outside the case 65 when viewed from the Z-axis direction. The bolt B is inserted from one restraint body 50 toward the other restraint body 50. A nut N is screwed to the tip of the bolt B. Thereby, the pair of restraining bodies 50, 50 apply a restraining load to the laminate 25, the positive electrode termination electrode 30, the negative electrode termination electrode 40, and the case 65. As a result, the inside of the case 65 is sealed. In the through hole 50a of the bolt B, the inner periphery of the through hole and the bolt seat surface and the peripheral surface thereof are insulated.

  The power storage device 10 including the spacer 60 and the case 65 as described above is manufactured as follows. That is, as shown in FIG. 2, the spacer 60 made of rubber-based resin is disposed along the peripheral edge 41 c of the current collector 41 in the negative electrode termination electrode 40. At this time, the spacer 60 is arrange | positioned inside the peripheral edge 41c so that the distance with the peripheral edge 41c may become predetermined length. Next, the bipolar electrode 12 is placed on the spacer 60. The bipolar electrode 12 is placed so that the distance between the spacer 60 and the peripheral edge 16c of the current collector 16 is the predetermined length.

  Next, a spacer 60 is disposed along the periphery of the upper surface of the current collector 16 in the bipolar electrode 12. At this time, the spacer 60 is arrange | positioned inside the peripheral edge 16c so that the distance with the peripheral edge 16c may become the said predetermined length. Next, the bipolar electrode 12 is placed on the spacer 60. The bipolar electrode 12 is placed so that the distance between the spacer 60 and the peripheral edge 16c of the current collector 16 is the predetermined length. In this way, the adjacent bipolar electrodes 12 are stacked while maintaining the distance between the current collectors 16 (first step).

  Next, the laminated body 25 including the plurality of bipolar electrodes 12, the separator 14, the positive terminal electrode 30, and the negative terminal electrode 40 stacked via the spacer 60 is hot-pressed in the stacking direction. Thereby, both ends of the spacer 60 in the Z-axis direction are in a molten state, and the current collector 16 or the current collectors 31 and 41 and the spacer 60 are welded. And as FIG. 3 shows, the primary product P1 integrated as the laminated body 25 is formed (2nd process).

  Next, after fixing the primary product P1 serving as the insert part to the molding die, a resin for forming the case 65 is injected into the molding die (insert molding), and the outside of the insert part is wrapped with a molten resin and solidified (first). Three steps). Thereby, the secondary product in which the resin forming the case 65 and the insert part are integrated is completed. Next, after the positive electrode terminal member 35 is disposed on one of both end portions of the secondary product and the negative electrode terminal member 45 is disposed on the other end, these are sandwiched by a pair of restraining bodies 50, 50, and the bolt B and nut N To fasten the pair of restraining bodies 50, 50 together (fourth step). Thereby, the power storage device 10 in a state in which the stacked body 25 is pressurized by the pair of restraining bodies 50 and 50 is completed.

  Next, the effect of the electrical storage apparatus 10 of 1st embodiment is demonstrated. In the power storage device 10 of the first embodiment, the spacer 60 made of a rubber-based resin that keeps the interval between the current collectors 16 of the adjacent bipolar electrodes 12 is disposed along the peripheral edge 16 c of the current collector 16. The spacer 60 can prevent the electrolyte from leaking outside the current collector 16. Furthermore, in the power storage device 10 having this configuration, the case 65 that holds the peripheral edge 16 c of the current collector 16 is disposed outside the spacer 60, so that the electrolyte may leak through the spacer 60. However, leakage of the electrolytic solution can be prevented by the case 65 disposed on the outer side. As a result, the sealing performance can be improved.

  Further, in the method for manufacturing the power storage device 10 of the present embodiment, the stacked body 25 in which the bipolar electrodes 12 are stacked through the separator 14 is integrated by the spacer 60. In the case of integrating a non-integrated laminate with a resin case 65 by means of 65, it takes time and effort to fix each component constituting the laminate with a jig or the like. Can be omitted.

  As mentioned above, although one embodiment was described in detail, the present invention is not limited to the above-mentioned embodiment.

  For example, as shown in FIG. 4, a convex portion 60 c may be formed on the outer peripheral surface of the spacer 60, and a concave portion 65 d may be formed on the inner peripheral surface of the case 65. The convex portion 60 c formed on the outer peripheral surface of the spacer 60 and the concave portion 65 d formed on the inner peripheral surface of the case 65 are fitted to each other. Thereby, the spacer 60 and the case 65 can be integrated more firmly. In addition, the uneven | corrugated shape structure with which the outer peripheral surface of the spacer 60 and the inner peripheral surface of the case 65 mutually fit is not limited above. For example, a concave portion is formed on the outer peripheral surface of the spacer 60, a convex portion is formed on the inner peripheral surface of the case 65, or irregularities are formed on the outer peripheral surface of the spacer 60, and irregularities are formed on the inner peripheral surface of the case 65. Then, the outer peripheral surface of the spacer 60 and the inner peripheral surface of the case 65 may be fitted to each other.

  In the said embodiment or modification, although the example which draws out the terminal which can perform charging / discharging of the electrical storage apparatus 10 from the side surface of the laminated body 25 was given and demonstrated, it is not limited to this. For example, it may be provided at both ends in the Z-axis direction, that is, at both ends in the stacking direction. In this case, each of the pair of restraining bodies 50, 50 can be formed of a conductive member, and a terminal electrically connected to each of the restraining bodies 50, 50 can be provided. In addition, a conductive member electrically connected to the terminal may be embedded in each of the pair of restraining bodies 50 and 50.

  Moreover, although the electrical storage apparatus 10 gave and demonstrated the example of the nickel hydride secondary battery in the said embodiment or modification, a lithium ion secondary battery may be sufficient. In this case, the positive electrode active material is, for example, a composite oxide, metallic lithium, sulfur or the like. Examples of the negative electrode active material include carbon such as graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, and soft carbon, alkali metals such as lithium and sodium, metal compounds, and SiOx (0.5 ≦ x ≦ 1.5). And metal oxides such as boron and carbon added with boron.

  DESCRIPTION OF SYMBOLS 10 ... Power storage device, 12 ... Bipolar electrode, 14 ... Separator, 16 ... Current collector, 16c ... Periphery of current collector, 18 ... Positive electrode layer, 20 ... Negative electrode layer, 25 ... Laminate, 30 ... Positive electrode termination electrode, 31 ... current collector, 31c ... peripheral edge of current collector, 33 ... positive electrode layer, 35 ... positive electrode terminal member, 40 ... negative electrode termination electrode, 41 ... current collector, 41c ... peripheral edge of current collector, 43 ... negative electrode layer, 45 ... negative electrode terminal member, 50 ... restraint body, 60 ... spacer, 60a ... outer peripheral surface, 65 ... case, 65c ... convex part, 65d ... concave part.

Claims (4)

A power storage device in which a plurality of bipolar electrodes each having a positive electrode layer provided on one surface of a current collector and a negative electrode layer provided on the other surface of the current collector are stacked via a separator,
A spacer made of a rubber-based resin that keeps an interval between the current collectors of the adjacent bipolar electrodes;
A case made of resin arranged so as to surround the outside of the spacer, and
The spacer is disposed along the periphery of the current collector at a predetermined interval inside the periphery, and the case holds the periphery of the current collectors. .   The power storage device according to claim 1, wherein an outer peripheral surface of the spacer and an inner peripheral surface of the case have a concavo-convex shape to be fitted to each other.   The electrical storage apparatus of Claim 1 or 2 which is a nickel hydride secondary battery. A method of manufacturing a power storage device in which a positive electrode layer is provided on one surface of a current collector and a negative electrode layer is provided on the other surface of the current collector, wherein a plurality of bipolar electrodes are stacked via a separator. ,
A first step of laminating a spacer made of a rubber-based resin along the periphery of the current collector while maintaining a gap between the current collectors of the adjacent bipolar electrodes;
A second step of forming a primary product integrated by hot pressing the plurality of bipolar electrodes stacked via the spacers in the stacking direction;
A third step of forming a secondary product by forming a case made of resin surrounding the outside of the spacer in the primary product and holding the peripheral edge of the current collector by insert molding;
A fourth step of fastening the secondary product in a state of being pressed by a restraint disposed at both ends in the lamination direction of the bipolar electrode;
A method for manufacturing a power storage device, comprising:

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