JP2018101489A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of improving output characteristics, while restraining up-sizing.SOLUTION: A power storage device 10 including a power storage module 12 where multiple bipolar electrodes 32, provided with a positive electrode layer on one side of an electrode plate 34 and a negative electrode layer on the other side of the electrode plate, are laminated in one direction via a separator 40, is further provided with an array body 11 where the power storage modules are arranged in one direction, and a conductor 14 that is one metallic body arranged between adjoining power storage modules, in contact with both power storage modules. The power storage modules arranged in one direction are connected electrically in series via the conductor. The conductor has thermal conductivity higher than that of the contact surface 12a with the conductor in the power storage module.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device.

  A power storage module (bipolar battery) is known in which a bipolar electrode, in which a positive electrode is formed on one surface of an electrode plate and a negative electrode is formed on the other surface, is laminated in one direction via a separator that holds an electrolyte. And the electrical storage apparatus (battery unit) which electrically connected such an electrical storage module is disclosed. For example, Patent Document 1 discloses a power storage device in which a plurality of power storage modules are electrically connected in parallel and a heat dissipation structure is provided on a conductor that electrically connects power storage modules adjacent to each other. In the power storage device described in Patent Document 1, it is possible to efficiently dissipate heat while suppressing an increase in size.

JP 2009-117105 A

  However, in the above-described conventional technique, it is necessary to draw out wiring and the like on the side surface of the power storage device that is in the direction intersecting the stacking direction, and there is a limit to downsizing the size. Further, such a power storage device is required to improve output characteristics.

  An object of the present invention is to provide a power storage device that can improve output characteristics while suppressing an increase in size.

  A power storage device according to the present invention is a power storage device in which a plurality of bipolar electrodes each provided with a positive electrode layer on one surface of an electrode plate and a negative electrode layer on the other surface of the electrode plate are stacked in one direction with a separator interposed therebetween. A power storage device including a module, an array in which power storage modules are arrayed in one direction, and a conductor disposed between the power storage modules adjacent to each other and in contact with the power storage module. The storage modules arranged in one direction are electrically connected in series via a conductor, and at least one of the conductors has a higher thermal conductivity than the contact surface of the storage module with the conductor. have.

  In the power storage device, current flows along the arrangement direction (one direction) of the power storage modules, so there is no need to draw out wiring or the like in a direction intersecting the arrangement direction. Therefore, it is possible to avoid an increase in size in the direction crossing the arrangement direction. Further, in the power storage device, the conductor having high thermal conductivity is arranged in contact with the power storage module, so that heat generated in the power storage module can be radiated. Therefore, it is not necessary to arrange a heat radiating plate that is usually arranged separately from the conductor, and the size in the arrangement direction can be suppressed. In addition, in the case where the power storage modules arranged in one direction are electrically connected in parallel via the conductor, that is, in the conductor, compared to the case where the current flows in the direction intersecting the one direction in the conductor. The current path can be shortened and the cross-sectional area of the current path can be increased. Therefore, since the internal resistance of the conductor portion is reduced, the output characteristics can be improved.

  In the power storage device according to the present invention, the conductor may be disposed in a region where the power storage module is disposed when viewed from one direction. In this power storage device, since the conductor does not jump out from the power storage module in a direction intersecting in one direction, the size of the entire device can be further reduced.

  In the power storage device according to the present invention, a through hole extending in a direction intersecting with one direction may be formed inside the conductor. In this power storage device, for example, a fluid having high thermal conductivity can be circulated through the through-hole, so that heat dissipation can be further improved.

  In the power storage device according to the present invention, a refrigerant may be circulated in the through hole. In this power storage device, the heat dissipation in the conductor can be further improved. The refrigerant may be an insulating material. Thereby, even if it is a case where a refrigerant | coolant leaks from a through-hole, for example, a short circuit can be prevented. The refrigerant may be a gas. In this case, the heat dissipation of the conductor can be improved more easily.

  The power storage device according to the present invention may be configured as a nickel metal hydride secondary battery. Also in the nickel-hydrogen secondary battery configured as described above, output characteristics can be improved while suppressing an increase in size.

  According to the present invention, it is possible to dissipate heat generated in the power storage module while suppressing an increase in size, and it is possible to improve output characteristics.

It is a schematic sectional drawing which shows one Embodiment of an electrical storage apparatus. It is a schematic sectional drawing which shows the electrical storage module contained in the electrical storage apparatus of FIG. It is a schematic sectional drawing which shows one Embodiment of the electrical storage apparatus which concerns on a modification. It is a schematic sectional drawing which shows one Embodiment of the electrical storage apparatus which concerns on the further 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 3 show an XYZ orthogonal coordinate system.

  The power storage device 10 shown in FIG. 1 is used as a battery for various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage module 12 is, for example, a bipolar battery. Examples of the power storage module 12 include secondary batteries such as nickel hydride secondary batteries and lithium ion secondary batteries, but may be electric double layer capacitors. In the following description, a nickel metal hydride secondary battery is illustrated.

  The plurality of power storage modules 12 are stacked via a conductor 14 such as a metal plate to form an array 11. The conductor 14 is one metal body disposed between the power storage modules 12 and 12 adjacent to each other, and is disposed in contact with both the power storage modules 12 and 12 adjacent to each other. The conductor 14 is made of, for example, a metal material such as aluminum or copper. When the conductor 14 is viewed from the stacking direction (Z direction), the power storage module 12 and the conductor 14 have, for example, a rectangular shape. When viewed from the stacking direction, the conductor 14 is smaller than the power storage module 12, but may be the same as or larger than the power storage module 12. In other words, the conductor 14 is disposed in a region where the power storage module 12 is disposed when viewed from the stacking direction. The conductor 14 is electrically connected to the adjacent power storage module 12. Thereby, the some electrical storage module 12 is connected in series in the lamination direction.

  The conductors 14 are also arranged outside the power storage modules 12 positioned at both ends in the stacking direction of the power storage modules 12. That is, the conductors 14 are also arranged at both ends of the array body 11 in the stacking direction. In the stacking direction, a positive electrode terminal 24 is connected to the conductor 14 located at one end, and a negative electrode terminal 26 is connected to the conductor 14 located at the other end. The positive terminal 24 may be integral with the conductor 14 to be connected. The negative electrode terminal 26 may be integrated with the conductor 14 to be connected. The positive electrode terminal 24 and the negative electrode terminal 26 extend in a direction (X direction) intersecting the stacking direction. The positive and negative terminals 24 and 26 can charge and discharge the power storage device 10.

  The conductor 14 also functions as a heat radiating plate for releasing heat generated in the power storage module 12. Specifically, the conductor 14 has higher thermal conductivity than the contact surface 12 a with the conductor 14 in the power storage module 12. In addition, a through hole 14 a extending in a direction (Y direction) intersecting the stacking direction is provided inside the conductor 14. The through hole 14 a communicates from one side surface facing each other in the conductor 14 to the other side surface. The through holes 14a are arranged in a stacking direction and a direction (X direction) intersecting the stacking direction. When a gaseous refrigerant such as air passes through such a through hole 14a, heat generated in the power storage module 12 can be efficiently released to the outside. The size of the conductor 14, the material of the conductor 14, the size of the through holes 14a, the number of the through holes 14a, and the like are adjusted as appropriate so that the temperature of the power storage device 10 does not exceed 50 ° C, for example. The power storage module 12 may be provided with a device that actively circulates (circulates) air through the through hole 14a.

  The power storage device 10 may include a restraining member 15 that restrains the alternately stacked power storage modules 12 and conductors 14 in the stacking direction. The restraining member 15 includes a pair of restraining plates 16 and 17 and a connecting member (bolt 18 and nut 20) for joining the restraining plates 16 and 17 together. For example, an insulating film 22 such as a resin film is disposed between the restraining plates 16 and 17 and the conductor 14. Each restraint plate 16 and 17 is comprised, for example with metals, such as iron.

  When viewed from the stacking direction, each of the restraining plates 16 and 17 and the insulating film 22 has, for example, a rectangular shape. The insulating film 22 is larger than the conductor 14, and the restraining plates 16 and 17 are larger than the power storage module 12. When viewed from the stacking direction, an insertion hole 16 a through which the shaft portion of the bolt 18 is inserted is provided at a position on the outer side of the power storage module 12 at the edge of the restraint plate 16. Similarly, when viewed from the stacking direction, an insertion hole 17 a through which the shaft portion of the bolt 18 is inserted is provided at the edge of the restraint plate 17 at a position outside the power storage module 12. When each restraint plate 16, 17 has a rectangular shape when viewed from the stacking direction, the insertion hole 16 a and the insertion hole 16 b are located at the corners of the restraint plates 16, 17.

  One constraining plate 16 is abutted against the conductor 14 connected to the negative electrode terminal 26 via the insulating film 22, and the other constraining plate 17 applies the insulating film 22 to the conductor 14 connected to the positive electrode terminal 24. Has been hit through. For example, the bolt 18 is passed through the insertion hole 16a from one restraint plate 16 side to the other restraint plate 17 side, and a nut 20 is screwed onto the tip of the bolt 18 protruding from the other restraint plate 17. ing. As a result, the insulating film 22, the conductor 14, and the power storage module 12 are sandwiched and unitized, and a restraining load is applied in the stacking direction.

  As shown in FIG. 2, the power storage module 12 includes a stacked body 30 in which a plurality of bipolar electrodes 32 are stacked. When viewed from the stacking direction of the bipolar electrode 32, the stacked body 30 has, for example, a rectangular shape. A separator 40 may be disposed between the adjacent bipolar electrodes 32. The bipolar electrode 32 includes an electrode plate 34, a positive electrode layer 36 provided on one surface of the electrode plate 34, and a negative electrode layer 38 provided on the other surface of the electrode plate 34. In the stacked body 30, the positive electrode layer 36 of one bipolar electrode 32 faces the negative electrode layer 38 of one bipolar electrode 32 adjacent in the stacking direction across the separator 40, and the negative electrode layer 38 of one bipolar electrode 32 is It faces the positive electrode layer 36 of the other bipolar electrode 32 adjacent in the stacking direction with the separator 40 interposed therebetween.

  In the stacking direction, an electrode plate 34 (negative electrode side termination electrode) having a negative electrode layer 38 disposed on the inner surface is disposed at one end of the stacked body 30, and a positive electrode layer 36 is disposed on the inner surface at the other end. An electrode plate 34 (positive terminal electrode) is disposed. The negative electrode layer 38 of the negative electrode side termination electrode is opposed to the positive electrode layer 36 of the uppermost bipolar electrode 32 with the separator 40 interposed therebetween. The positive electrode layer 36 of the positive electrode termination electrode faces the negative electrode layer 38 of the lowermost bipolar electrode 32 with the separator 40 interposed therebetween. The electrode plates 34 of these termination electrodes are connected to the adjacent conductors 14 (see FIG. 1).

  The power storage module 12 includes a frame body 50 that holds the edge portion 34 a of the electrode plate 34 on the side surface 30 a of the stacked body 30 that extends in the stacking direction of the bipolar electrodes 32. The frame body 50 is configured to surround the side surface 30 a of the stacked body 30. The side surface 50 s has, for example, a rectangular shape when viewed from the stacking direction of the bipolar electrode 32. In this case, the side surface 50s is composed of four rectangular surfaces. The frame 50 can include a first resin portion 52 that holds the edge portion 34a of the electrode plate 34 and a second resin portion 54 that is provided around the first resin portion 52 when viewed from the stacking direction.

  The first resin portion 52 constituting the inner wall of the frame 50 is provided from one surface (surface on which the positive electrode layer 36 is formed) of the electrode plate 34 of each bipolar electrode 32 to the end surface of the electrode plate 34 at the edge 34a. Yes. When viewed from the stacking direction of the bipolar electrodes 32, each first resin portion 52 is provided over the entire circumference of the edge portion 34 a of the electrode plate 34 of each bipolar electrode 32. Adjacent first resin portions 52 are welded to each other on the surface extending outside the other surface (surface on which the negative electrode layer 38 is formed) of the electrode plate 34 of each bipolar electrode 32. As a result, the edge portion 34 a of the electrode plate 34 of each bipolar electrode 32 is buried and held in the first resin portion 52. Similarly to the edge portion 34 a of the electrode plate 34 of each bipolar electrode 32, the edge portions 34 a of the electrode plates 34 disposed at both ends of the laminated body 30 are also held in a state of being buried in the first resin portion 52. Thus, an internal space V that is airtightly partitioned by the electrode plates 34 and 34 and the first resin portion 52 is formed between the electrode plates 34 and 34 adjacent in the stacking direction. In the internal space V, for example, an electrolytic solution (not shown) made of an alkaline solution such as an aqueous potassium hydroxide solution is accommodated.

  The second resin portion 54 constituting the outer wall of the frame body 50 is a cylindrical portion that extends over the entire length of the multilayer body 30 in the lamination direction of the bipolar electrode 32. The second resin portion 54 covers the outer surface of the first resin portion 52 extending in the stacking direction of the bipolar electrode 32. The second resin portion 54 is welded to the outer surface of the first resin portion 52 on the inner surface that extends in the stacking direction of the bipolar electrode 32.

  The electrode plate 34 is a rectangular metal foil made of nickel, for example. The edge 34 a of the electrode plate 34 is an uncoated region where the positive electrode active material and the negative electrode active material are not coated, and the uncoated region is buried in the first resin portion 52 constituting the inner wall of the frame body 50. It is an area to be held. Examples of the positive electrode active material constituting the positive electrode layer 36 include nickel hydroxide. Examples of the negative electrode active material constituting the negative electrode layer 38 include a hydrogen storage alloy. The formation region of the negative electrode layer 38 on the other surface of the electrode plate 34 is slightly larger than the formation region of the positive electrode layer 36 on one surface of the electrode plate 34. The electrode plate 34 may be formed from a conductive resin.

  The separator 40 is formed in a sheet shape, for example. Examples of the material forming the separator 40 include porous films made of polyolefin resins such as polyethylene (PE) and polypropylene (PP), woven fabrics and nonwoven fabrics made of polypropylene, polyethylene terephthalate (PET), methylcellulose and the like. It is. Moreover, the separator 40 may be reinforced with a vinylidene fluoride resin compound. The separator 40 is not limited to a sheet shape, and may be formed in a bag shape.

  The frame 50 (the first resin portion 52 and the second resin portion 54) is formed in a rectangular cylindrical shape by, for example, injection molding using an insulating resin. Examples of the resin material constituting the frame 50 include polypropylene (PP), polyphenylene sulfide (PPS), and modified polyphenylene ether (modified PPE).

  In the power storage device 10 of the above-described embodiment, the conductor 14 has higher thermal conductivity than the contact surface 12a of the power storage module 12 with the conductor 14, and therefore the heat generated in the power storage module 12 is transferred to the conductor. The heat can be dissipated through 14.

  Moreover, since current flows along the arrangement direction (Z direction) of the power storage modules 12, it is not necessary to draw out wiring or the like in a direction (X direction and / or Y direction) intersecting the arrangement direction. Therefore, it is possible to avoid an increase in size in the direction crossing the arrangement direction. Furthermore, in the power storage device 10 of one embodiment, the conductor 14 having high thermal conductivity is arranged in contact with the power storage module 12, so that the heat generated in the power storage module 12 can be radiated. Therefore, it is not necessary to arrange a heat radiating plate that is usually arranged separately from the conductors 14, so that the size in the arrangement direction can be suppressed.

  Further, in the power storage device 10 of one embodiment described above, when the power storage modules arranged in the stacking direction are electrically connected in parallel via a conductor (hereinafter referred to as “conventional power storage device”). In other words, the current path in the conductor 14 can be shortened and the cross-sectional area of the current path can be widened compared to the case where a current is passed in a direction crossing one direction (X direction) in the conductor. That is, in the power storage device 10 of the above-described embodiment, the resistance can be reduced as compared with the conventional power storage device.

This point will be specifically described with reference to FIG. When the resistivity of the conductor 14 is ρ (Ω · m), the cross-sectional area of the conductor 14 is A (m ² ), and the length of the conductor 14 is L (m), the resistance R of the conductor 14 is It is shown by the following formula.
R = ρ × (L / A)
Then, for example, a conductor similar to the dimension and shape shown in FIG.

  The length L of the conductor 14 of the power storage device 10 of the above embodiment is the length in the Z direction, and the length L of the conductor of the conventional power storage device is the length of the X direction. Therefore, the length L of the conductor 14 of the power storage device 10 of the above embodiment is shorter than the length L of the conductor of the conventional power storage device. The cross-sectional area A of the conductor 14 of the power storage device 10 of the above embodiment is the product of the X direction and the Y direction, and the cross-sectional area A of the conductor of the conventional power storage device is the product of the Y direction and the X direction. is there. Therefore, the cross-sectional area A of the conductor 14 of the power storage device 10 of the above embodiment is wider than the cross-sectional area A of the conductor of the conventional power storage device. From the above, the resistance R of the conductor 14 of the power storage device 10 of the above embodiment is smaller than the resistance R of the conductor of the conventional power storage device. Therefore, the power storage device 10 of the above embodiment can improve the output characteristics.

  In the power storage device 10 of the above-described embodiment, the conductor 14 is disposed in a region where the power storage module 12 is disposed when viewed from the stacking direction. Thereby, since the conductor 14 does not jump out of the power storage module 12 in the X direction or the Y direction, the size of the entire power storage device 10 can be further reduced.

  In the power storage device 10 of the above embodiment, a through hole 14 a extending in the Y direction intersecting the stacking direction is formed inside the conductor 14. Thereby, gas, such as air, can be distribute | circulated to the through-hole 14a, and it becomes possible to improve heat dissipation.

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

  In the above embodiment, the configuration in which air is circulated through the through hole 14a formed in the conductor 14 has been described as an example. However, as shown in FIG. 3, a liquid refrigerant F is circulated instead of air. Also good. Examples of the refrigerant F include insulating oil and the like. In this case, the heat dissipation in the conductor 14 can be further improved. The refrigerant F is an insulating material. In this case, for example, even when the refrigerant F leaks from the through hole 14a, a short circuit due to the refrigerant F can be prevented.

  In the above embodiment or modification, the example in which the through hole 14a is formed inside the conductor 14 has been described, but as shown in FIG. 4, the conductor 14 has a through hole instead of the conductor 14. A non-conductor 114 may be employed. Even in this case, since the conductor 14 has conductivity, the power storage modules 12 arranged in the arrangement direction are electrically connected in series via the conductor 14. Moreover, since the conductor 114 has higher thermal conductivity than the contact surface 12a with the conductor 14 in the power storage module 12, heat dissipation can be ensured. Even in the power storage device 10 having such a configuration, output characteristics can be improved while suppressing an increase in size.

  In the above embodiment, all the conductors 14 included in the power storage device 10 have been described with reference to an example in which the through holes 14a are provided while having higher thermal conductivity than the contact surface 12a in the power storage module 12. Only the selected conductor may have higher thermal conductivity than the contact surface 12a in the power storage module 12, or the through hole 14a may be provided.

  Similarly, in the above modification, the example in which all the conductors 14 included in the power storage device 10 have higher thermal conductivity than the contact surface 12a in the power storage module 12 has been described. Only the conducted conductor may have a higher thermal conductivity than the contact surface 12 a of the power storage module 12.

  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, 11 ... Array, 12 ... Power storage module, 12a ... Contact surface, 14, 114 ... Conductor, 14a ... Through hole, 30 ... Laminated body, 32 ... Bipolar electrode, 34 ... Electrode plate, 36 ... Positive electrode Layer, 38 ... negative electrode layer, 40 ... separator, 50 ... frame.

Claims (7)

A power storage device comprising a power storage module in which a plurality of bipolar electrodes each having a positive electrode layer provided on one surface of an electrode plate and a negative electrode layer provided on the other surface of the electrode plate are stacked in one direction with a separator interposed therebetween. And
An array in which the power storage modules are arrayed in the one direction;
A metal body disposed between the storage modules adjacent to each other, and a conductor disposed in contact with both of the storage modules adjacent to each other.
The power storage modules arranged in the one direction are electrically connected in series via the conductor,
The electrical storage device, wherein the electrical conductor has higher thermal conductivity than a contact surface with the electrical conductor in the electrical storage module.   The power storage device according to claim 1, wherein the conductor is disposed in a region where the power storage module is disposed when viewed from the one direction.   The power storage device according to claim 1, wherein a through-hole extending in a direction intersecting the one direction is formed in the conductor.   The power storage device according to claim 3, wherein a refrigerant is circulated in the through hole.   The power storage device according to claim 4, wherein the refrigerant is an insulating substance.   The power storage device according to claim 4, wherein the refrigerant is a gas.   The electrical storage apparatus as described in any one of Claims 1-6 which is a nickel hydride secondary battery.

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