JP2018014251A - Battery pack and method of manufacturing battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack which can secure adhesion between a battery module and a heat dissipation member without being subject to limitation of a size of the heat dissipation member, and to provide a method of manufacturing the batter pack.SOLUTION: A battery pack 1 is formed by fixing a battery module 3 to a housing 2 through brackets 7 and includes: an elastic thin plate 21 disposed between the battery module 3, the brackets 7 and the housing 2; and a heat conduction sheet 9 which is disposed at one surface side of the battery module 3 so as to adhere to the thin plate 21. The thin plate 21 is biased to the housing 2 side by fastening force of fixing bolts 13 which fix the brackets 7 to the housing 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery pack and a method for manufacturing the battery pack.

  Conventionally, for example, there is a power supply system described in Patent Document 1. This conventional power supply system includes a battery module including a plurality of batteries, a cooling device that cools the battery module, and a fixing member that fixes the battery module to the cooling device. The cooling device is addressed to one end surface side of the battery module, and the fixing member is engaged with the battery module so as to sandwich the cooling device, and urges the cooling device toward the one end surface side of the battery module.

Japanese Patent Laying-Open No. 2015-232922

  If an air layer or the like exists between the battery module and the heat radiating member, the air layer may hinder heat dissipation. Therefore, from the viewpoint of ensuring the heat dissipation of the battery module, the adhesion between the battery module and the heat dissipation member is important. In the conventional configuration described above, the cooling device is attached by a fixing member to ensure the adhesion of the cooling device to the battery module. However, in the configuration in which the fixing member is engaged with the battery module so as to sandwich the cooling device, the size of the cooling device and the size of the one end surface of the battery module need to be matched to some extent. Due to such limitations, for example, when the casing itself to which the battery module is attached is used as a heat radiating member, it is difficult to apply the conventional configuration described above.

  The present invention has been made to solve the above-described problem, and a battery pack capable of ensuring adhesion between the battery module and the heat radiating member without being limited by the size of the heat radiating member, and such a battery. It aims at providing the manufacturing method of a pack.

  A battery pack according to one aspect of the present invention is a battery pack in which a battery module is fixed to a housing via a bracket, and the battery module and an elastic thin plate disposed between the bracket and the housing; A heat conductive sheet disposed on one side of the battery module so as to be in close contact with the thin plate, and the thin plate is urged toward the housing side by a fastening force of a fixing bolt for fixing the bracket to the housing.

  In this battery pack, the fastening force of the fixing bolt is applied to an elastic thin plate, and the thin plate is urged toward the housing by the elastic force of the thin plate itself. As a result, the thin plate can be brought into close contact with the housing as the heat radiating member. In addition, since the heat conductive sheet is disposed on one side of the battery module, the heat conductive sheet follows the shape of the thin plate even when the thin plate is urged to the housing side. Adhesion of is sufficiently secured. Therefore, in this battery pack, the heat generated in the battery module can be radiated favorably to the casing. This configuration can be applied regardless of the size of the housing.

  Further, the heat conductive sheet may be a liquid TIM cured product. By using such a heat conductive sheet, the followability of the heat conductive sheet to the thin plate can be sufficiently enhanced. Therefore, the adhesion between the battery module and the thin plate can be more sufficiently ensured.

  A battery pack manufacturing method according to one aspect of the present invention is a battery pack manufacturing method in which a battery module is fixed to a housing via a bracket, and a battery module in which a heat conductive sheet is arranged on one side; A thin plate arranging step of arranging a thin plate having elasticity between the case and a bracket fixing step of fixing a bracket provided on the battery module to the case with a fixing bolt with the thin plate interposed therebetween. In the arranging step, the thin plate is arranged so that the fixing surface by the bracket is an inclined surface inclined to the housing side with respect to the opposing surface to the heat conductive sheet. In the bracket fixing step, the inclined surface is flush with the opposing surface. Tighten the fixing bolts as follows.

  In this battery pack manufacturing method, when the bracket is fixed to the housing, the fixing bolt is fastened so that the inclined surface of the thin plate is flush with the opposing surface. Thereby, the fastening force of the fixing bolt acts on the thin plate having elasticity, and the thin plate is biased toward the housing by the elastic force of the thin plate itself. Therefore, the thin plate can be brought into close contact with the housing as the heat radiating member. In addition, since the heat conductive sheet is disposed on one side of the battery module, the heat conductive sheet follows the shape of the thin plate even when the thin plate is urged to the housing side. Adhesion of is sufficiently secured. Therefore, in the battery pack obtained by this manufacturing method, the heat generated in the battery module can be radiated favorably to the casing. This method can be applied regardless of the size of the housing.

  Moreover, you may use the hardened | cured material of a liquid TIM as a heat conductive sheet. By using such a heat conductive sheet, the followability of the heat conductive sheet to the thin plate can be sufficiently enhanced. Therefore, the adhesion between the battery module and the thin plate can be more sufficiently ensured.

  Moreover, you may arrange | position a thin plate so that the boundary part of an opposing surface and an inclined surface may oppose a heat conductive sheet in a thin plate arrangement | positioning process. When the inclined surface is flush with the opposing surface by the fastening force of the fixing bolt, plastic deformation may occur at the boundary portion between the inclined surface and the opposing surface. Therefore, by arranging the thin plate so that the boundary portion between the facing surface and the inclined surface faces the heat conductive sheet, the heat conductive sheet is made to follow the place where plastic deformation has occurred, thereby improving the adhesion between the battery module and the thin plate. It is possible to ensure sufficient.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness between a battery module and a heat radiating member is securable without receiving the restriction | limiting of the size of a heat radiating member.

It is the schematic which shows one Embodiment of a battery pack. It is the schematic which shows the manufacturing process of the battery pack shown in FIG. FIG. 3 is a schematic diagram illustrating a subsequent process of FIG. 2. It is a figure which shows the mode of the elastic deformation of a thin plate. It is a principal part expansion schematic of the battery pack shown in FIG.

  Hereinafter, preferred embodiments of a battery pack and a battery pack manufacturing method according to one aspect of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing an embodiment of a battery pack. The battery pack 1 is used as a battery for an industrial vehicle such as a forklift. As shown in FIG. 1, the battery pack 1 is configured by fixing the battery module 3 to the housing 2 via a bracket 7.

  The housing 2 has a substantially rectangular parallelepiped box shape, for example. When the battery pack 1 is mounted on a forklift, a function as a counterweight of the forklift may be added by providing a weight member on the outer surface of the housing 2. The material forming the housing 2 is, for example, a metal material such as iron, so that the housing 2 also functions as a heat radiating member that releases heat generated in the battery module 3 to the outside.

  The battery module 3 includes an array 5 including a plurality of battery cells 4, an elastic body 6 disposed at one end of the array 5 in the array direction, and sandwiching the array 5 and the elastic body 6 in the array direction. A pair of brackets 7, 7 and a restraining member 8 that restrains the array body 5 and the elastic body 6 in the array direction are configured.

  The battery cell 4 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. The battery cell 4 is configured by accommodating an electrode assembly in a case into which a non-aqueous electrolyte is injected. The electrode assembly is obtained by stacking a positive electrode, a negative electrode, and a separator in a predetermined order. In this embodiment, a sheet-like positive electrode is accommodated in a bag-shaped separator, and a bag-shaped separator and a sheet-shaped negative electrode each containing a positive electrode are alternately stacked.

  Each battery cell 4 may be held by a frame-shaped cell holder. Each battery cell 4 may be provided with a heat transfer plate. A middle plate may be disposed between the array body 5 and the elastic body 6.

  On one surface side of the array 5, a heat conductive sheet 9 is provided. The heat conductive sheet 9 is a cured product of a liquid TIM (Thermal Interface Material) and has a certain elasticity. The TIM includes a heat conductive material such as polyurethane, and has a high heat conductivity of, for example, 1.5 W / m · K or more. The thermal conductivity of TIM is preferably 2.0 W / m · K or more, more preferably 2.5 W / m · K or more, and further preferably 3.0 W / m · K or more. . The heat conductive sheet 9 may have adhesiveness.

  The elastic body 6 is a member used for the purpose of preventing damage of the battery cell 4, the bracket 7, and the restraining member 8 due to restraint load when the battery cell 4 is expanded. The elastic body 6 is formed in a rectangular plate shape by a rubber sponge made of urethane, for example. Examples of other forming materials of the elastic body 6 include ethylene propylene diene rubber (EPDM), chloroprene rubber, and silicon rubber. The elastic body 6 is not limited to rubber and may be a spring material or the like.

  The bracket 7 is, for example, a metal plate member. The bracket 7 has two flat plate portions 7A and 7B orthogonal to each other, and has a substantially L shape as a whole. The flat plate portion 7 </ b> A has a rectangular shape that is the same as or slightly larger than the planar shape of the battery cell 4 and the elastic body 6 as viewed from the arrangement direction, and functions as an end plate for the arrangement body 5 and the elastic body 6. On the other hand, the flat plate portion 7B projects in a rectangular shape from one edge portion of the flat plate portion 7A and functions as a fixing piece for fixing the battery module 3 to the housing 2.

  One bracket 7 has a flat plate portion 7A in contact with one arrangement end of the array 5 and a flat plate portion 7B facing the same direction as one surface of the array 5 (the surface on which the heat conductive sheet 9 is provided). Has been placed. The other bracket 7 is arranged such that the flat plate portion 7A is in contact with the elastic body 6 and the flat plate portion 7B faces the same direction as one surface of the battery module 3 (the surface on which the heat conductive sheet 9 is provided). Yes. The battery module 3 is firmly fixed to the housing 2 by screwing a fixing bolt 13 into a bolt hole 12 on the housing 2 side through an insertion hole 10 provided in the flat plate portion 7B.

  In the present embodiment, the restraining member 8 is constituted by a restraining bolt 14 and a nut 15. For example, the restraint bolt 14 is passed from the flat plate portion 7A of one bracket 7 toward the flat plate portion 7A of the other bracket 7. A nut 15 is screwed to a tip portion of the restraining bolt 14 protruding from the flat plate portion 7A of the other bracket 7. Thereby, each battery cell 4 and the elastic body 6 are clamped and unitized, and a predetermined restraining load is applied to each battery cell 4 and the elastic body 6 by the fastening force of the nut 15.

  In fixing the battery module 3 to the housing 2, an elastic thin plate 21 is disposed between the battery module 3 and the housing 2. The thin plate 21 is formed in a rectangular shape corresponding to the planar shape on the one surface side of the battery module 3, for example, by spring stainless steel whose strength is increased by cold rolling or the like. It is preferable that the thickness of the wall portion of the housing 2 has sufficient rigidity so as not to be affected by the deformation of the thin plate 21. For example, when the thickness of the wall portion of the housing 2 is about 10 mm to 20 mm, the thickness of the thin plate 21 is preferably about 0.6 mm to 3.2 mm.

  The thin plate 21 has a facing surface 21A facing the heat conductive sheet 9 provided on one surface side of the array 5 and a fixing surface 21B facing the flat plate portion 7B of the bracket 7 and fixed by the fixing bolt 13. ing. An insertion hole 22 through which the fixing bolt 13 is inserted is provided in the fixing surface 21B. The thin plate 21 is fastened together with the housing 2 together with the flat plate portion 7B of the bracket 7 by a fixing bolt 13 passing through the insertion hole 10 and the insertion hole 22.

  In a state where the fixing bolt 13 is fastened, the fixing surface 21B is formed by elastic deformation of an inclined surface 21C (see FIG. 2) described later when the fixing bolt 13 is fastened, and is flush with the facing surface 21A. By making the fixing surface 21B flush with the opposing surface 21A by elastic deformation of the inclined surface 21C, the opposing surface 21A is urged toward the housing 2 by the elastic force of the thin plate 21 itself. Due to this urging force, one surface side of the facing surface 21 </ b> A is in close contact with the housing 2. Further, the heat conductive sheet 9 having a certain elasticity is in close contact with the other surface side of the facing surface 21A. Thereby, the heat dissipation path from each battery cell 4 to the housing 2 via the heat conductive sheet 9 and the thin plate 21 is established.

  When manufacturing the battery pack 1 described above, first, as shown in FIG. 2, the battery module 3 in which the heat conductive sheet 9 is disposed on one side and the thin plate 21 having elasticity between the bracket 7 and the housing 2 are provided. Arrangement (thin plate arrangement process). The method for forming the heat conductive sheet 9 is not particularly limited. For example, a liquid TIM is applied to one surface side of the battery module 3 using a doctor blade method, and this is left in the atmosphere for about a half day to a day. The flat heat conductive sheet 9 can be obtained by drying. Further, the heat conductive sheet 9 may be a plate-like TIM fixed to one surface side of the battery module 3 by adhesion or the like.

  In the thin plate 21 in the initial state in the thin plate arranging step, a portion that becomes the fixing surface 21B by the bracket 7 is an inclined surface 21C that is inclined at an obtuse angle with respect to the facing surface 21A with the heat conductive sheet 9. The inclination angle θ of the inclined surface 21C with respect to the facing surface 21A is, for example, about 5 ° to 45 °. In the thin plate arranging step, the thin plate 21 is arranged in a direction in which the inclined surface 21C is inclined toward the housing 2, and the thin plate 21 is sandwiched between the battery module 3 and the housing 2.

  Next, as shown in FIG. 3, the bracket 7 provided in the battery module 3 is fixed to the housing 2 by the fixing bolt 13 with the thin plate 21 interposed (bracket fixing step). In the bracket fixing step, after the shaft portion of the fixing bolt 13 is passed through the insertion hole 10 provided in the flat plate portion 7B of the bracket 7 and the insertion hole 22 provided in the inclined surface 21C of the thin plate 21, the shaft portion is Screwed into the bolt hole 12 of the housing 2.

  By fastening the fixing bolt 13, the inclined surface 21 </ b> C of the thin plate 21 is sandwiched between the flat plate portion 7 </ b> B of the bracket 7 and the housing 2 and is elastically deformed. At this time, the inclined surface 21 </ b> C sandwiched between the bracket 7 and the housing 2 is deformed so as to be flush with the opposing surface 21 </ b> A, and becomes a fixed surface 21 </ b> B. When the inclined surface 21C is deformed to become the fixed surface 21B, the elastic force of the thin plate 21 itself is, as shown in FIGS. 4 (a) and 4 (b), the inclination angle θ between the inclined surface 21C and the opposing surface 21A. Acts to maintain.

  For this reason, when the inclined surface 21C is deformed so as to be flush with the opposing surface 21A, an elastic force acts on the opposing surface 21A in the direction in which the inclined surface 21C was inclined before the deformation. Therefore, after fastening of the fixing bolt 13, the fixing surface 21 </ b> B and the opposing surface 21 </ b> A of the thin plate 21 are flush with each other between the battery module 3 and the bracket 7 and the housing 2. It will be in the state urged | biased to the housing | casing 2 side by fastening force (refer FIG. 3). As a result, the one surface side of the thin plate 21 is in close contact with the housing 2, and the heat conductive sheet 9 is in close contact with the other surface side of the thin plate 21, and the housing 2 is connected from each battery cell 4 via the heat conductive sheet 9 and the thin plate 21. A heat dissipation path leading to is established.

  As described above, in the manufacturing method of the battery pack 1, when the bracket 7 is fixed to the housing 2, the fixing bolt 13 is fastened so that the inclined surface 21C of the thin plate 21 is flush with the opposing surface 21A. . Thereby, the fastening force of the fixing bolt 13 acts on the thin plate 21 having elasticity, and the thin plate 21 is biased toward the housing 2 by the elastic force of the thin plate 21 itself. Therefore, the thin plate 21 can be brought into close contact with the housing 2 as a heat radiating member.

  In addition, since the heat conductive sheet 9 is disposed on one surface side of the battery module 3, the heat conductive sheet 9 follows the shape of the thin plate 21 even when the thin plate 21 is biased toward the housing 2 side. In addition, the adhesion between the battery module 3 and the thin plate 21 is sufficiently secured. Therefore, in the battery pack 1 obtained by this manufacturing method, the heat generated in the battery module 3 can be radiated favorably to the housing 2. This method can be applied regardless of the size of the housing 2.

  In the present embodiment, a liquid TIM cured product is used as the heat conductive sheet 9. By using such a heat conductive sheet 9, the followability of the heat conductive sheet 9 to the thin plate 21 can be sufficiently enhanced. Therefore, the adhesion between the battery module 3 and the thin plate 21 can be more sufficiently ensured.

  As described above, when the inclined surface 21C is elastically deformed so as to be flush with the opposing surface 21A by fastening the fixing bolt 13, plastic deformation may occur at the boundary portion between the opposing surface 21A and the fixing surface 21B. is there. When plastic deformation occurs, convex distortion may occur at the boundary between the facing surface 21A and the fixed surface 21B. In such a case, it is preferable to arrange the thin plate 21 so that the boundary portion P between the facing surface 21A and the inclined surface 21C faces the heat conductive sheet 9 in the thin plate arranging step described above. In this case, as shown in FIG. 5, the heat conductive sheet 9 having a certain elasticity follows the boundary portion P where plastic deformation has occurred, and the adhesion between the battery module 3 and the thin plate 21 can be sufficiently secured.

  DESCRIPTION OF SYMBOLS 1 ... Battery pack, 2 ... Housing, 3 ... Battery module, 7 ... Bracket, 9 ... Heat conduction sheet, 13 ... Fixing bolt, 21 ... Thin plate, 21A ... Opposite surface, 21B ... Fixed surface, 21C ... Inclined surface, P ... the boundary.

Claims (5)

A battery pack in which a battery module is fixed to a housing via a bracket,
An elastic thin plate disposed between the battery module and the bracket and the housing;
A heat conductive sheet disposed on one side of the battery module so as to be in close contact with the thin plate,
The thin plate is a battery pack that is urged toward the casing by a fastening force of a fixing bolt that fixes the bracket to the casing.   The battery pack according to claim 1, wherein the heat conductive sheet is a cured product of liquid TIM. A battery pack manufacturing method in which a battery module is fixed to a housing via a bracket,
A thin plate disposing step of disposing a thin plate having elasticity between the battery module in which a heat conductive sheet is disposed on one side and the housing;
A bracket fixing step of fixing the bracket provided to the battery module in a state where the thin plate is interposed to the housing with a fixing bolt,
In the thin plate arranging step, the thin plate is arranged so that a fixing surface by the bracket is an inclined surface inclined to the housing side with respect to a surface facing the heat conductive sheet,
The method of manufacturing a battery pack, wherein, in the bracket fixing step, the fixing bolt is fastened so that the inclined surface is flush with the facing surface.   The method for manufacturing a battery pack according to claim 3, wherein a liquid cured product of TIM is used as the heat conductive sheet.   The method of manufacturing a battery pack according to claim 3 or 4, wherein, in the thin plate arranging step, the thin plate is arranged so that the facing surface, the inclined surface, and a boundary portion face the heat conductive sheet.

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