JP2017212145A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device capable of improving a structural strength.SOLUTION: In a power storage device 100, a partition wall 60 provided between one electrode assembly 20 and the other electrode assembly 20 in a case 10 has a heat dissipation member 70 inside of a resin material 61. The heat dissipation member 70 projects from a bottom wall portion 10a to the outside, and accordingly dissipate heat generated in the electrode assembly 20 to the outside of the case 10 through the heat dissipation member 70 of the partition wall 60. Here, the heat dissipation member 70 is arranged inside of the resin material in a state of integrated with the resin material 61 inside of the resin material 61. Thereby, even when structured of the resin material 61, the partition wall 60 is supported by the heat dissipation member 70 integrated with the resin material 61, which increases the strength. From the above description, the power storage device 100 can improve the structural strength.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power storage device.

  A power storage device including a stacked electrode assembly in which positive electrodes and negative electrodes are alternately stacked via separators is known (see Patent Document 1). The power storage device includes a case, and a plurality of electrode assemblies are accommodated in the case. A heat radiating member is provided between the electrode assemblies.

JP 2011-103265 A

  Here, a resin battery case in which the electrode assembly is accommodated together with the electrolytic solution may be provided in the case of the power storage device. However, when the thickness of the resin battery case is reduced, sufficient structural strength is obtained. It may not be obtained.

  An object of one embodiment of the present invention is to provide a power storage device that can improve structural strength.

  A power storage device according to one aspect of the present invention includes a plurality of stacked electrode assemblies in which positive electrodes and negative electrodes are alternately stacked via separators, and first wall portions that house the electrode assemblies and face each other And a partition having a second wall and a partition provided between the one electrode assembly and the other electrode assembly in the case, wherein the partition is the first of the case The heat dissipation member extends from the wall portion to the second wall portion side and is disposed in a state of being integrated with the resin material inside the resin material, and the heat dissipation member protrudes from the first wall portion to the outside. ing.

  In this power storage device, the partition provided between the one electrode assembly and the other electrode assembly in the case has a heat radiating member inside the resin material. Since this heat radiating member protrudes outside from the first wall portion, the heat generated in the electrode assembly can be radiated to the outside of the case through the heat radiating member of the partition wall. Here, the heat radiating member is arranged in an integrated state with the resin material inside the resin material. Thereby, even if it is a case where a partition is comprised with a resin material, intensity | strength can be raised because the thermal radiation member integrated with the said resin material supports a partition. As described above, the power storage device can improve the structural strength.

  The heat radiating member may have an extended portion extending along the first wall portion outside the case. Thus, since the heat radiating member has the extended portion, the heat radiating area outside the case can be expanded.

  A plurality of partition walls having a heat radiating member may be provided, and the extended portion of one heat radiating member may be separated from the extended portion of the other heat radiating member. In this case, the heat radiation area can be increased by using a portion between the extended portion of one heat radiating member and the extended portion of the other heat radiating member as a heat radiating surface.

  A plurality of partition walls having a heat radiating member may be provided, and the extended portion of one heat radiating member may be connected to the extended portion of another heat radiating member. In this case, since each heat radiating member can be handled as one member connected by the expansion part, handling at the time of manufacture becomes easy.

  The extension portion may be separated from the first wall portion outside the case. In this case, a heat radiation area can be expanded by making the part spaced apart from the 1st wall part also into a heat radiation surface among expansion parts.

  The heat radiating member may extend to the second wall portion side of the positive electrode and the negative electrode from the region where the active substance is applied. Since the electrode assembly generates heat in the positive electrode and the negative electrode in the region where the active material is applied, the heat radiating member extends to the second wall side from the region, thereby efficiently generating heat generated from the region. It can be recovered well.

  The power storage device may be, for example, a nickel hydrogen secondary battery or a lithium ion secondary battery.

  According to one aspect of the present invention, the structural strength of a power storage device can be improved.

It is sectional drawing which shows typically the electrical storage apparatus which concerns on embodiment of this invention. It is an expanded sectional view which shows typically the electrical storage apparatus which concerns on a modification. It is sectional drawing which shows typically the electrical storage apparatus which concerns on a comparative example.

  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.

  FIG. 1 is a cross-sectional view schematically showing the power storage device according to this embodiment. FIG. 1 shows an XYZ orthogonal coordinate system.

  The power storage device 100 shown in FIG. 1 is a secondary battery such as a nickel hydride secondary battery. The power storage device 100 can be mounted on a vehicle such as a forklift, a hybrid vehicle, or an electric vehicle. Power storage device 100 may be a prismatic battery having a sealed structure. The power storage device 100 can include a case 10, a plurality of electrode assemblies 20 housed in the case 10, and a partition wall 60 disposed between the electrode assemblies 20.

  The case 10 is a box that houses a plurality of electrode assemblies 20 therein. The case 10 has a bottom wall portion (first wall portion) 10a, a top wall portion 10b facing the bottom wall portion 10a above, and a bottom surface facing the vertical direction (X-axis direction in the drawing). A pair of side walls 10c and 10d that connect the wall 10a and the upper wall 10b and a pair of side walls that connect the bottom wall 10a and the upper wall 10b in a direction orthogonal to the vertical direction (Y-axis direction in the figure). Part (not shown). In the present embodiment, the case 10 has a longitudinal direction in the X-axis direction. Each wall portion of the case 10 according to the present embodiment may be made of resin. A positive terminal 12 and a negative terminal 16 are provided on the upper wall portion 10 b of the case 10.

  A plurality of partition walls 60 are provided in the case 10 so as to be spaced apart at predetermined intervals along the X-axis direction. The partition wall 60 extends from the bottom wall portion 10a to the upper wall portion 10b side. The partition wall 60 also extends between a pair of side wall portions facing each other in the Y-axis direction. The partition wall 60 is fixed to the bottom wall portion 10a and the pair of side wall portions facing each other in the Y-axis direction. On the other hand, the upper end of the partition wall 60 is spaced apart from the upper wall portion 10b. A connection structure for connecting the electrode assemblies 20 can be disposed in the gap between the partition wall 60 and the upper wall portion 10b. The partition wall 60 may extend further upward so that the upper end may be fixed to the upper wall portion 10b. In this case, a through hole or the like may be formed in order to pass the connection structure for connecting the electrode assembly 20.

  The partition wall 60 includes a first partition wall 60A in which the heat dissipation member 70 is provided, and a second partition wall 60B in which the heat dissipation member 70 is not provided. The first partition wall 60A (part excluding the heat dissipation member 70) and the second partition wall 60B may be made of a resin material. In addition, as a resin material, you may use the material similar to the case where the case 10 is comprised with resin, for example, you may use PP, PE, PPS, modified PPE, etc. In the present embodiment, the first partition walls 60A and the second partition walls 60B are alternately provided along the X-axis direction. However, the number of the first partition walls 60A is not particularly limited, and one first partition wall 60A may be provided for two or more second partition walls 60B, and all the partition walls in the case 10 are the first partition walls. It may be a partition wall 60A. The detailed configuration of the heat dissipation member 70 of the first partition wall 60A will be described later.

  A region partitioned by the partition wall 60 in the inside of the case 10 is configured as a battery case 21 in which the electrode assembly 20 is disposed and filled with an electrolytic solution (not shown). Each wall part which partitions off the battery case 21 is comprised with a resin material, and the battery case 21 may be comprised as a resin battery case. As the electrolytic solution, for example, an alkaline solution such as an aqueous potassium hydroxide solution can be used.

  The electrode assembly 20 is a laminated electrode assembly in which sheet-like positive electrodes 30 and sheet-like negative electrodes 40 are alternately laminated via separators 50. The separator 50 may be, for example, a sheet-like separator, or a bag-like separator that can accommodate the positive electrode 30 or the negative electrode 40. For example, the separator 50 may be a nonwoven fabric made of a synthetic fiber that has been subjected to a hydrophilic treatment. In the present embodiment, the positive electrode 30, the negative electrode 40, and the separator 50 of the electrode assembly 20 are stacked in the X-axis direction. That is, the stacking direction of the sheets of the electrode assembly 20 and the direction in which the partition walls 60 are aligned are the same.

The positive electrode 30 includes a positive electrode main body 32 and a positive electrode tab 34 protruding from the upper end of the positive electrode main body 32. The positive electrode main body 32 may include a metal foil 36 and a positive electrode active material layer 37 formed on one or both surfaces of the metal foil 36. As the metal foil 36, for example, a porous nickel foil or the like can be used. The positive electrode active material layer 37 includes, for example, particles of nickel hydroxide (Ni (OH) ₂ ). Nickel hydroxide (Ni (OH) ₂ ) functions as a positive electrode active material. The positive electrode main body 32 has, for example, a rectangular shape. The positive electrode tab 34 may be a metal foil integrated with the metal foil of the positive electrode main body 32. The positive electrode tab 34 has, for example, a rectangular shape. An active material layer is not substantially formed on the positive electrode tab 34.

  The negative electrode 40 includes a negative electrode body 42 and a negative electrode tab 44 that protrudes from the upper end of the negative electrode body 42. The negative electrode main body 42 may include a metal foil 46 and a negative electrode active material layer 47 formed on one or both surfaces of the metal foil 46. As the metal foil 46, for example, a porous nickel foil, a mesh-like nickel-plated steel plate (punching metal), or the like can be used. The negative electrode active material layer 47 includes, for example, particles of a hydrogen storage alloy. Hydrogen stored in the hydrogen storage alloy functions as a negative electrode active material. The negative electrode main body 42 has, for example, a rectangular shape. The negative electrode tab 44 may be a metal foil integrated with the metal foil of the negative electrode main body 42. The negative electrode tab 44 has, for example, a rectangular shape. An active material layer is not substantially formed on the negative electrode tab 44.

  The positive electrode main body 32, the negative electrode main body 42, and the separator 50 may overlap with each other when viewed from the stacking direction (X-axis direction) of the positive electrode 30 and the negative electrode 40. When viewed from the stacking direction, the positive electrode tab 34 and the negative electrode tab 44 may be disposed so as not to overlap. Within the same electrode assembly 20, the positive electrode tabs 34 of the positive electrodes 30 are electrically connected to each other by a connection member 65. Within the same electrode assembly 20, the negative electrode tabs 44 of the respective negative electrodes 40 are electrically connected by a connection member 65. Thereby, in the same electrode assembly 20, the cell comprised by the positive electrode main body 32, the negative electrode main body 42, and the separator 50 becomes a structure mutually connected in parallel. Further, the negative electrode tab 44 of the electrode assembly 20 at the end in the X-axis direction (in FIG. 1, the end on the negative side in the X-axis direction) is electrically connected to the negative electrode terminal 16 via the connection member 65. . The positive electrode tab 34 of the electrode assembly 20 at the end portion in the X-axis direction (the end portion on the positive side in the X-axis direction in FIG. 1) is electrically connected to the positive electrode terminal 12 via the connection member 65. Further, the positive electrode tab 34 of one electrode assembly 20 is connected to the negative electrode tab 44 of the adjacent electrode assembly 20 (adjacent to the positive side in the X-axis direction) via the connection member 65. As described above, each electrode assembly 20 is connected in series.

  Next, the configuration of the first partition wall 60A including the heat dissipation member 70 will be described. As shown in FIG. 1, the first partition wall 60 </ b> A includes a heat radiating member 70 that is disposed in an integrated state with the resin material 61 inside the resin material 61. The “integrated state” means a state in which the resin material 61 and the heat radiating member 70 are fixed without using bolts or the like and can be handled as one component when the power storage device 100 is assembled. At the time of manufacture, the first partition wall 60A is formed by insert molding in which a resin is poured into the mold in a state where the heat dissipation member 70 is disposed in the mold. Moreover, the heat radiating member 70 protrudes outside from the bottom wall part 10a.

  Specifically, the heat dissipation member 70 includes an insert portion 71 disposed inside the resin material 61 of the first partition 60A, and an exposed portion 72 disposed outside the first partition 60A and the case 10. Prepare.

  The insert portion 71 extends along the Z-axis direction (here, the vertical direction) together with the first partition wall 60A. The insert portion 71 extends in the Y-axis direction together with the first partition wall 60A. The upper end portion 71a of the insert portion 71 is disposed in the resin material 61 without being exposed from the upper end portion of the resin material 61 of the first partition wall 60A. Further, the heat radiating member 70 extends to the positive side (upper wall portion 10b side) in the Z-axis direction from the positive electrode main body 32 and the negative electrode main body 42 (region where the active material is applied) of the positive electrode 30 and the negative electrode 40. ing. Therefore, the upper end portion 71 a of the insert portion 71 is disposed on the positive side in the Z-axis direction with respect to the upper end portions of the positive electrode main body 32 and the negative electrode main body 42.

  The exposed portion 72 includes an extended portion 73 that extends straight from the insert portion 71 and extends from the case 10 to the outside, and an extended portion 74 that expands the surface area of the exposed portion 72. The extending portion 73 is a portion that further extends from the lower end portion of the insert portion 71 to the negative side in the Z-axis direction outside the case 10. Although the extension amount of the extension part 73 is not specifically limited, it is suppressed to a range in which the power storage device 100 is not excessively enlarged. The extended portion 74 is a portion that extends in the X-axis direction along the bottom wall portion 10 a outside the case 10. The extension part 74 extends from the lower end of the extension part 73 to both the positive side and the negative side in the X-axis direction. However, the extension part 74 may extend only to one side in the X-axis direction.

  In the present embodiment, the extended portion 74 is separated from the bottom wall portion 10 a outside the case 10. That is, the upper surface 74c of the extended portion 74 is separated from the bottom wall portion 10a to the negative side (that is, the lower side) in the Z-axis direction, and a space is formed between the upper surface 74c and the bottom wall portion 10a. Note that the size of the space is adjusted by the size of the extension portion 74 in the X-axis direction and the extension amount of the extension portion 73.

  In the present embodiment, a plurality (here, three) of the first partition walls 60A having the heat radiating members 70 are provided, and therefore a plurality of (here, three) the heat radiating members 70 are also provided. The extended portion 74 of the negative heat radiating member 70 in the X-axis direction is separated from the extended portion 74 of the central heat radiating member 70 in the X-axis direction. That is, the end portion (the end portion on the positive side in the X-axis direction) 74a of the negative heat dissipation member 70 in the X-axis direction and the end portion (the end portion of the expansion portion 74 in the central heat-dissipation member 70 in the X-axis direction) A space is formed between the negative end 74b in the X-axis direction. An end portion (end portion on the negative side in the X axis direction) 74b of the positive side heat dissipation member 70 in the X axis direction and an end portion (X axis) of the extension portion 74 of the central heat dissipation member 70 in the X axis direction. A space is formed between the positive end of the direction 74a.

  In addition, although the shape when the insert part 71 and the exposed part 72 are seen from the X-axis direction may be a rectangular shape matching the first partition wall 60A, the shape is not particularly limited. The shape when the extended portion 74 is viewed from the Z-axis direction may be a rectangular shape having the same width as the insert portion 71, but the shape is not particularly limited.

  Next, functions and effects of the power storage device 100 according to the present embodiment will be described.

  For example, a power storage device 200 according to a comparative example as illustrated in FIG. 3 will be described. All the partition walls 60 of the power storage device 200 are second partition walls 60B that do not have a heat dissipation member. In the case where the partition wall 60 is made of resin and the thickness of the resin is to be reduced, such a power storage device 200 may not have sufficient structural strength.

  On the other hand, in the power storage device 100 according to the present embodiment, the partition wall 60 provided between the one electrode assembly 20 and the other electrode assembly 20 in the case 10 has the heat dissipation member 70 inside the resin material 61. doing. Since the heat radiating member 70 protrudes from the bottom wall portion 10 a to the outside, the heat generated in the electrode assembly 20 can be radiated to the outside of the case 10 through the heat radiating member 70 of the partition wall 60. Here, the heat radiating member 70 is arranged in an integrated state with the resin material 61 inside the resin material 61. Thus, even when the partition wall 60 is made of the resin material 61, the heat dissipation member 70 integrated with the resin material 61 supports the partition wall 60, so that the strength can be increased. As described above, the power storage device 100 can improve the structural strength.

  The heat dissipating member 70 has an extended portion 74 extending along the bottom wall portion 10 a outside the case 10. Thus, since the heat radiating member 70 has the extended part 74, the heat radiating area outside the case 10 can be expanded.

  A plurality of partition walls 60 each having the heat radiating member 70 are provided, and the extended portion 74 of one heat radiating member 70 is separated from the extended portions 74 of the other heat radiating members 70. In this case, the heat radiation area can be increased by using a portion between the expansion portion 74 of one heat radiation member 70 and the expansion portion 74 of another heat radiation member 70 as a heat radiation surface. When the upper surface 74c of the extended portion 74 is a heat radiating surface, the gap between the extended portion 74 of one heat radiating member 70 and the extended portion 74 of the other heat radiating member 70 functions as a gap for allowing air to pass through. To do.

  The extended portion 74 is separated from the bottom wall portion 10 a outside the case 10. In this case, the heat radiation area can be expanded by making the upper surface 74c of the extended portion 74, which is a part away from the bottom wall portion 10a, also a heat radiation surface.

  The heat radiating member 70 extends to the upper wall portion 10b side of the positive electrode 30 and the negative electrode 40 from the region where the active substance is applied. Since the electrode assembly 20 generates heat in the region where the active material is applied among the positive electrode 30 and the negative electrode 40, the heat dissipation member 70 is generated from the region by extending to the upper wall portion 10b side than the region. Heat can be recovered efficiently.

  As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment.

  For example, the power storage device of each embodiment may be a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, or may be an electric double layer capacitor, for example.

  For example, the case where the power storage device is a lithium ion secondary battery will be described. In this case, the positive electrode active material layer may include a positive electrode active material and a binder, and may include a conductive additive as necessary. The positive electrode active material is not particularly limited as long as it is a positive electrode active material for a lithium secondary battery. The positive electrode active material is, for example, a lithium compound. Examples of the lithium compound that can be used include lithium metal composite oxides such as lithium cobalt composite oxide, lithium nickel composite oxide, and lithium manganese composite oxide.

  The binder is, for example, a fluorine-containing resin such as polyvinylidene fluoride, polytetrafluoroethylene, or fluororubber, a thermoplastic resin such as polypropylene or polyethylene, an imide resin such as polyimide or polyamideimide, or an alkoxysilyl group-containing resin. Good. The conductive auxiliary agent is, for example, carbon-based particles such as carbon black, graphite, acetylene black (AB), ketjen black (registered trademark) (KB), vapor grown carbon fiber (VGCF) and the like. These can be added alone or in combination of two or more.

  The negative electrode metal foil is, for example, a copper foil. The negative electrode active material layer may include a negative electrode active material and the binder, and may include the conductive auxiliary agent as necessary. Examples of the negative electrode active material include a carbon-based material that can occlude and release lithium, an element that can be alloyed with lithium, an elemental compound that has an element that can be alloyed with lithium, or a polymer material. The example of a binder and a conductive support agent is the same as that of a positive electrode.

  Examples of the material forming the separator include a porous film made of a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a woven fabric or a non-woven fabric made of polypropylene, polyethylene terephthalate (PET), methylcellulose, and the like. .

  Further, the extended portion of one heat radiating member 70 may be connected to the extended portion of another heat radiating member 70. In this case, as shown in FIG. 2A, the insert portion 71 and the extension portion 73 of one heat radiating member 70 and the insert portion 71 and the extension portion 73 of the other heat radiating member 70 are continuously X. They are connected by an extension 174 extending in the axial direction. In this case, since each heat radiating member 70 is handled as one member connected by the expansion part 174, handling at the time of manufacture becomes easy.

  Further, the extended portion of the heat dissipation member 70 may not be separated from the bottom wall portion 10a. In this case, as shown in FIG. 2B, the upper surface 74c of the extended portion 74 is in contact with the bottom wall portion 10a without a gap. In this case, the extending portion 73 does not exist. Therefore, only the extended portion 74 projects from the bottom wall portion 10a to the outside.

  Further, the extended portion may be omitted, and the exposed portion of the heat dissipation member 70 may be only the extended portion.

  In addition, the wall part and partition of a case are not separate components, and may be integrated and comprised as one component.

  DESCRIPTION OF SYMBOLS 10 ... Case, 10a ... Bottom wall part (1st wall part), 10b ... Upper wall part (2nd wall part), 20 ... Electrode assembly, 30 ... Positive electrode, 40 ... Negative electrode, 50 ... Separator, 60 ... Partition wall 61... Resin material, 70... Heat radiating member, 74.

Claims (8)

A plurality of stacked electrode assemblies in which positive and negative electrodes are alternately stacked via separators;
A case containing the electrode assembly and having a first wall portion and a second wall portion facing each other;
In the case, a power storage device comprising: a partition wall provided between one of the electrode assemblies and the other electrode assembly,
The partition is
Extending from the first wall of the case to the second wall,
A heat dissipating member arranged in an integrated state with the resin material inside the resin material
The heat dissipation member is a power storage device that protrudes outward from the first wall portion.   The power storage device according to claim 1, wherein the heat dissipating member has an extended portion extending along the first wall portion outside the case. A plurality of the partition walls having the heat dissipation member are provided,
The power storage device according to claim 2, wherein the extended portion of one of the heat radiating members is separated from the extended portion of the other heat radiating member. A plurality of the partition walls having the heat dissipation member are provided,
The power storage device according to claim 2, wherein the extended portion of one of the heat radiating members is connected to the extended portion of the other heat radiating member.   The power storage device according to any one of claims 2 to 4, wherein the extension portion is separated from the first wall portion outside the case.   The electricity storage according to any one of claims 1 to 5, wherein the heat dissipation member extends to the second wall portion side of the positive electrode and the negative electrode from a region where an active material is applied. apparatus.   The power storage device according to any one of claims 1 to 6, wherein the power storage device is a nickel-hydrogen secondary battery.   The power storage device according to any one of claims 1 to 6, wherein the power storage device is a lithium ion secondary battery.

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