JP2018060648A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of improving heat dissipation of a laminate portion in which bipolar electrodes are laminated.SOLUTION: A power storage device 10 comprises a bipolar electrode 12 including a positive electrode layer 18 provided on one surface 16a of a collector 16, and a negative electrode layer 20 provided on the other surface 16b on the side opposite to the one surface. The bipolar electrode comprises a laminate 25 including a bipolar electrode group laminated in a Z-axis direction via a separator 14, and an insulating case 60 including a first resin part 60A which holds the collector by surrounding a side surface of the laminate and a second resin part 60B surrounding the first resin part. The first resin part is formed of a resin having corrosion resistance to an electrolytic solution. The second resin part is formed of a resin having a higher thermal conductivity than the first resin part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device.

  There is known a bipolar battery including 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 through a separator. For example, Patent Document 1 discloses a bipolar battery in which an end portion which is an outer shape is covered with a resin when the current collector is viewed from the lamination direction of the bipolar electrodes.

JP 2005-5163 A

  In a power storage device including the bipolar electrode, heat is generated during charging and discharging. However, in the conventional bipolar battery, since the end portion of the current collector plate is covered with the resin, the heat generated in the laminated body portion is orthogonal to the end portion of the current collector, that is, the bipolar electrode stacking direction. It is difficult to dissipate heat from, and heat dissipation is poor.

  An object of this invention is to provide the electrical storage apparatus which can improve the heat dissipation of the laminated body part by which the bipolar electrode was laminated | stacked.

  A power storage device according to the present invention is a power storage device having a bipolar electrode having a positive electrode layer provided on one surface of a current collector and a negative electrode layer provided on the other surface opposite to the one surface. A bipolar body including a bipolar electrode group in which bipolar electrodes are laminated in a first direction via a separator, a first resin part surrounding and holding a side surface of the multilayer body, and a second resin part surrounding the first resin part The first resin part is made of a resin having corrosion resistance to the electrolytic solution, and the second resin part has a higher thermal conductivity than the first resin part. It is formed from resin.

  In this power storage device, the first resin portion that surrounds and holds the side surface of the laminate has corrosion resistance to the electrolytic solution, so that it is not corroded by the electrolytic solution. Furthermore, since the second resin part having higher thermal conductivity than the first resin part is provided outside the first resin part, the heat generated in the laminate can be efficiently released to the outside of the case. it can. As a result, it is possible to improve the heat dissipation of the stacked body portion where the bipolar electrodes are stacked.

  The end portion of the current collector in the bipolar electrode when viewed from the first direction may be held by the second resin portion. In the power storage device having this configuration, the current collector of the bipolar electrode is held by both the first resin portion and the second resin portion, and the end portion thereof is held by the second resin portion having a relatively high thermal conductivity. ing. Thereby, the heat generated in the laminate can be effectively radiated to the outside of the case via the current collector.

  The power storage device may be configured as a nickel hydride secondary battery. In the nickel metal hydride secondary battery having this configuration, as described above, the heat dissipation of the stacked body portion where the bipolar electrodes are stacked can be improved.

  The 1st resin part may be formed from resin which has the corrosion resistance with respect to potassium hydroxide. The power storage device having this configuration is not corroded by the electrolytic solution retained in the laminate, even when configured as a nickel metal hydride secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, the heat dissipation of the laminated body part by which the bipolar electrode was laminated | stacked can be improved.

It is sectional drawing which shows typically the electrical storage apparatus which concerns on 1st embodiment. It is sectional drawing which shows typically the electrical storage apparatus which concerns on 2nd embodiment. It is sectional drawing which shows typically the electrical storage apparatus which concerns on 3rd 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.

  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 5 show an XYZ orthogonal coordinate system.

(First embodiment)
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 (bipolar electrode group), 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 case 60.

  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 (first 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, for example.

  The positive electrode termination electrode 30 is disposed at one end of the plurality of bipolar electrodes 12 (bipolar electrode group) in the Z-axis direction. 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 negative electrode termination electrode 40 is disposed at the other end of the plurality of bipolar electrodes 12 (bipolar electrode group) in the Z-axis direction. 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 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 60 c in the case 60 described in detail later, and is pulled out to the outside of the case 60. 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 60 c in the case 60 described in detail later, and is pulled out to the outside of the case 60. The lead portion 49 functions as a terminal that can charge and discharge the power storage device 10.

  As shown in FIG. 1, the case 60 is orthogonal to the Z-axis direction of the multilayer body 25 including the plurality of bipolar electrodes 12, the positive electrode termination electrode 30, and the negative electrode termination electrode 40 in the Z-axis direction. The edge part in the direction (end part used as the external shape when the laminated body 25 is seen from a Z-axis direction) is covered. In other words, the laminated body 25 is surrounded and held. The case 60 is a resin case formed in a cylindrical shape, and the case 60 is filled with an electrolytic solution.

  The case 60 includes a first resin portion 60A that surrounds and holds the side surface of the laminate 25, and a second resin portion 60B that surrounds the first resin portion 60A. 60 A of 1st resin parts are formed from the insulating resin which has corrosion resistance with respect to electrolyte solution (potassium hydroxide). Examples of the resin forming the first resin portion 60A include modified PPE (modified polyphenylene ether) and PPS (polyphenylene sulfide).

  The second resin portion 60B is formed of an insulating resin having a higher thermal conductivity than the first resin portion 60A. Note that the second resin portion 60B may not have corrosion resistance to the electrolytic solution (potassium hydroxide). The second resin portion 60B having a higher thermal conductivity than the first resin portion 60A may be formed, for example, by adding a filler to a resin such as PP (polypropylene), modified PPE, and PPS. Examples of the filler include alumina and copper.

  In the present embodiment, the end portion 16c of the current collector 16 in each bipolar electrode 12 when viewed from the Z-axis direction (first direction), the end portion 31c of the current collector 31 in the positive electrode termination electrode 30, and the negative electrode termination electrode 40. The end portion 41c of the current collector 41 is held by the second resin portion 60B. For example, the end of the current collector 16 of each bipolar electrode 12, the end 31 c of the current collector 31 of the positive electrode termination electrode 30, and the end 41 c of the current collector 41 of the negative electrode termination electrode 40 are embedded in the case 60. . When the end portions of the respective current collectors are held by the second resin portion 60B, the fillers are adjusted so that the current collectors are not short-circuited as conductive paths of the fillers.

  The pair of restraining bodies 50, 50 sandwich the stacked body 25 including the plurality of bipolar electrodes 12, the positive terminal electrode 30, and the negative terminal electrode 40 in the Z-axis direction. Further, the pair of restraining bodies 50, 50 sandwich the case 60 in addition to the stacked body 25. The pair of restraining bodies 50, 50 are made of a resin material having corrosion resistance to potassium hydroxide, such as PPS (polyphenylene sulfide). In addition, the one restraint body 50 and 50 may be formed with the material which has electroconductivity. In this case, an insulating sheet may be disposed between the restraining body 50 and the positive electrode terminal member 35.

  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 60 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. Accordingly, the pair of restraining bodies 50, 50 apply a restraining load to the plurality of bipolar electrodes 12, the plurality of separators 14, the positive electrode termination electrode 30, the negative electrode termination electrode 40, and the case 60. As a result, the inside of the case 60 is sealed.

  The power storage device 10 including the case 60 having the first resin portion 60A and the second resin portion 60B as described above is manufactured as follows. That is, first, after fixing the plurality of bipolar electrodes 12, the positive electrode termination electrode 30 and the negative electrode termination electrode 40 as insert parts to the molding die, a resin for forming the first resin portion 60A is injected into the molding die, and the insert The ends of the bipolar electrodes 12, the positive electrode termination electrode 30, and the negative electrode termination electrode 40 are wrapped with molten resin and solidified. Thereby, the primary product in which the resin and the insert part are integrated is completed.

  Next, the primary product is fixed to the molding die, a resin for forming the second resin portion 60B is injected, and the primary product and the second resin portion 60B are integrated. Thereby, the secondary product by which the side surface of the laminated body 25 was hold | maintained in case 60 which has 60 A of 1st resin parts and 2nd resin part 60B is completed. Next, the secondary product is sandwiched between the pair of restraining bodies 50, 50, and the pair of restraining bodies 50, 50 are fastened with the bolts B and the nuts N. 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 first resin portion 60A that surrounds and holds the side surface of the laminate 25 has corrosion resistance against the electrolytic solution (potassium hydroxide), and therefore is corroded by the electrolytic solution. There is nothing. Furthermore, since the second resin part 60B having higher thermal conductivity than the first resin part 60A is provided outside the first resin part 60A, the heat generated in the laminate 25 is efficiently transferred to the outside of the case 60. Can be escaped. As a result, it is possible to improve the heat dissipation of the laminated body 25 portion where the bipolar electrode 12 is laminated.

  In the power storage device 10 of the present embodiment, the current collector 16 of the bipolar electrode 12 is held by both the first resin portion 60A and the second resin portion 60B, and the end portion 16c has a relative thermal conductivity. Is held by the second resin portion 60B. Thereby, the heat generated in the stacked body 25 can be effectively radiated to the outside of the case 60 via the current collector 16.

(Second embodiment)
Next, the power storage device 110 according to the second embodiment will be described. The power storage device 110 shown in FIG. 2 is common in that it includes a case 60 composed of a first resin portion 60A and a second resin portion 60B, but its manufacturing method is different from that of the first embodiment. That is, in the first embodiment, the primary product is completed using a plurality of bipolar electrodes 12, the positive electrode termination electrode 30 and the negative electrode termination electrode 40 as inserts, whereas in the second embodiment, as shown in FIG. In addition, the primary product P <b> 1 is completed for each bipolar electrode 12, positive electrode termination electrode 30, and negative electrode termination electrode 40. In FIG. 4, illustration of the primary product including the positive electrode termination electrode 30 and the primary product including the negative electrode termination electrode 40 is omitted. Next, the first resin parts 60A in the primary product P1 are laminated while being thermally welded. Thereby, the secondary product on which the primary product P1 is laminated is completed.

  Next, the secondary product is fixed to the molding die, a resin for forming the second resin portion 60B is injected, and the secondary product and the second resin portion 60B are integrated. Thereby, the tertiary product by which the side surface of the laminated body 25 was hold | maintained in case 60 which has 60 A of 1st resin parts and the 2nd resin part 60B is completed. Next, the tertiary product is sandwiched between a pair of restraining bodies 50, 50, and the pair of restraining bodies 50, 50 are fastened with bolts B and nuts N. Thereby, the power storage device 110 in a state where the stacked body 25 is pressurized by the pair of restraining bodies 50 and 50 is completed.

  This power storage device 110 can also obtain the same effects as the power storage device 10 of the first embodiment.

(Third embodiment)
Next, the power storage device 210 according to the third embodiment will be described. The power storage device 210 shown in FIG. 3 is common in that it includes a case 60 composed of a first resin portion 60A and a second resin portion 60B, but its manufacturing method is different from the first embodiment and the second embodiment. Yes. That is, in the first embodiment, the primary product is completed using a plurality of bipolar electrodes 12, the positive electrode termination electrode 30 and the negative electrode termination electrode 40 as inserts, whereas in the third embodiment, as shown in FIG. In addition, the primary product P <b> 1 is completed for each bipolar electrode 12, positive electrode termination electrode 30, and negative electrode termination electrode 40.

  Next, the primary product P1 is fixed to the molding die, the resin forming the second resin portion 60B is injected, and the primary product P1 and the second resin portion 60B are integrated. Thereby, the secondary product P2 in which the first resin portion 60A and the second resin portion 60B are integrated for each of the bipolar electrode 12, the positive electrode termination electrode 30, and the negative electrode termination electrode 40 as shown in FIG. 5 is completed. To do. Next, the first resin portion 60A and the second resin portion 60B in the secondary product P2 are stacked while being thermally welded. Thereby, the tertiary product on which the secondary product P2 is laminated is completed. Next, the tertiary product is sandwiched between a pair of restraining bodies 50, 50, and the pair of restraining bodies 50, 50 are fastened with bolts B and nuts N. Thereby, the power storage device 110 in a state where the stacked body 25 is pressurized by the pair of restraining bodies 50 and 50 is completed.

  This power storage device 210 can also achieve the same effects as the power storage device 10 of the first embodiment.

  As mentioned above, although 1st, 2nd, and 3rd embodiment was described in detail, this invention is not limited to the said embodiment.

  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 10,110,210 ... Power storage device, 12 ... Bipolar electrode, 14 ... Separator, 16 ... Current collector, 18 ... Positive electrode layer, 20 ... Negative electrode layer, 25 ... Laminate, 30 ... Positive electrode termination electrode, 31 ... Current collector 33 ... Positive electrode layer, 35 ... Positive electrode terminal member, 40 ... Negative electrode termination electrode, 41 ... Current collector, 43 ... Negative electrode layer, 45 ... Negative electrode terminal member, 50 ... Restraint body, 60 ... Case, 60A ... First resin part , 60B ... second resin part.

Claims (4)

A power storage device having a bipolar electrode having a positive electrode layer provided on one surface of a current collector and a negative electrode layer provided on the other surface opposite to the one surface,
A laminate including a bipolar electrode group in which the bipolar electrode is laminated in a first direction via a separator;
A first resin part surrounding and holding the side surface of the laminate, and an insulating case having a second resin part surrounding the first resin part,
The first resin portion is formed of a resin having corrosion resistance to an electrolytic solution, and the second resin portion is formed of a resin having a higher thermal conductivity than the first resin portion. .   The power storage device according to claim 1, wherein an end portion of the current collector in the bipolar electrode when viewed from the first direction is held by the second resin portion.   The electrical storage apparatus of Claim 1 or 2 which is a nickel hydride secondary battery.   The power storage device according to claim 3, wherein the first resin portion is made of a resin having corrosion resistance to potassium hydroxide.

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