JP2018049697A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent loosening of a fastening member without changing fastening axial force and the number of the fastening member.SOLUTION: A battery pack 1 comprises: a housing 2; a battery module 3; and a bolt 4. The battery module 3 comprises: an array body 5; and brackets 61 and 62 arranged on both ends in a first direction of the array body 5. The housing 2 comprises: a metal base material 31; and a coating member 32 covering the surface of the metal base material 31. An inner face 23a of the housing 2 includes: a coated region Rc which is covered with the coating member 32; and an uncoated region Rm from which the surface of the metal base material 31 is exposed. A coefficient of friction generated between a fixed portion 61b and the uncoated region Rm when the fixed portion 61b of the bracket 61 is fixed to the uncoated region Rm is greater than a coefficient of friction generated between the fixed portion 61b and the coated region Rc when the fixed portion 61b is fixed to the coated region Rc. The fixed portion 61b is fixed to the uncoated region Rm via the bolt 4.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a battery pack.

  Patent Document 1 describes a battery pack including a plurality of battery modules. In this battery pack, the battery module is fixed to the side wall of the housing by bolts.

JP-A-2015-109200

  The casing of the battery pack may be painted. In such a battery pack, when the battery module is fixed by a fastening member such as a bolt, there is a possibility that the fastening member may be loosened due to slipping between the joint surfaces. It is conceivable to suppress loosening by increasing the fastening axial force (fastening torque) of the fastening member. However, since the upper limit of the fastening axial force of the fastening member is determined by the strength of the fastening member, there is a limit in preventing loosening by increasing the fastening axial force. Moreover, it is also possible to suppress loosening by increasing the number of fastening members. However, the number of fastening members may be limited due to restrictions such as mounting space.

  The present invention provides a battery pack capable of suppressing loosening of a fastening member without changing the fastening axial force and the number of fastening members.

  A battery pack according to an aspect of the present invention includes a housing having a support surface, a battery module accommodated in the housing, and a fastening member that fixes the battery module to the support surface. The battery module is disposed at the other end in the first direction of the array, the first bracket disposed at one end in the first direction of the array, the array having a plurality of battery cells arrayed in the first direction. A second bracket. The first bracket and the second bracket include a main body part for sandwiching the array body in the first direction, and a fixing part that extends from the main body part to the opposite side of the array body and is fixed to the support surface by a fastening member. Prepare each. The housing includes a metal substrate and a covering member that covers the surface of the metal substrate. The support surface includes a covered region covered with the covering member and an uncovered region where the surface of the metal substrate is exposed. The coefficient of friction that occurs between the fixed part and the non-covered area when the fixed part is fixed to the non-covered area is the coefficient of friction that occurs between the fixed part and the covered area when the fixed part is fixed to the coated area. Bigger than. The fixing portion of the first bracket is fixed to the uncovered region by the fastening member.

  In this battery pack, the battery module is fixed to the housing by fixing the fixing portion of the first bracket and the fixing portion of the second bracket to the support surface of the housing by the fastening member. The fixing portion of the first bracket is fixed to an uncovered region where the surface of the metal substrate is exposed. The coefficient of friction that occurs between the fixed part and the non-covered area when the fixed part is fixed to the non-covered area is the coefficient of friction that occurs between the fixed part and the covered area when the fixed part is fixed to the coated area. Therefore, rather than fixing the fixing portion of the first bracket to the covering region, the fixing of the fixing portion of the first bracket to the non-covering region suppresses the slip between the fixing portion of the battery module and the support surface. The As a result, it is possible to suppress loosening of the fastening member without changing the fastening axial force and the number of fastening members.

  The fixing portion of the first bracket may be provided with a first insertion hole for inserting the fastening member. The fixing portion of the second bracket may be provided with a second insertion hole for inserting the fastening member. The length along the first direction of the second insertion hole may be larger than the length along the first direction of the first insertion hole. In this case, the second insertion hole provided in the fixed portion of the second bracket extends along the first direction. For this reason, even if the length along the first direction of the battery module varies due to a manufacturing error or the like, the variation can be absorbed by the second insertion hole, so that the reliability of the battery module can be improved. It becomes.

  The fixing part of the second bracket may be fixed to the covering region by a fastening member. When the battery pack is used, the battery cell may expand and the length along the first direction of the battery module may increase. The second insertion hole provided in the fixing portion of the second bracket extends along the first direction. For this reason, the position along the first direction of the fixing portion of the second bracket can be adjusted by the length along the first direction of the second insertion hole with respect to the mounting position of the second bracket on the support surface. Since the fixing portion of the second bracket is fixed to the covering region, the fixing portion of the second bracket is more slidable with respect to the support surface than the fixing portion of the first bracket. Thereby, even if the battery cell expands and the length along the first direction of the battery module increases, the fixing part of the second bracket can slide along the first direction, and the battery cell expands. It can be absorbed.

  The fixing portion of the second bracket may be fixed to the uncovered region by a fastening member. In this case, since not only the fixing portion of the first bracket but also the fixing portion of the second bracket is fixed to the uncovered region, the sliding of the battery module with respect to the support surface is further suppressed. As a result, it is possible to further suppress the loosening of the fastening member without changing the fastening axial force and the number of fastening members.

  The coating member may be a coating composed of a cationic paint. In this case, since the surface of the metal substrate is covered with the cationic paint in the covering region, it is possible to suppress the occurrence of rust in the covering region.

  According to the present invention, it is possible to suppress loosening of the fastening member without changing the fastening axial force and the number of fastening members.

It is a perspective view which shows the battery pack which concerns on this embodiment. It is a perspective view which shows the external appearance of the battery module shown by FIG. It is the figure which looked at the battery module shown by FIG. 2 from the housing | casing side. It is a figure which shows the state by which the battery module is attached to the inner surface of the housing | casing shown by FIG. It is a figure which shows the state by which the battery module was removed from the inner surface of the housing | casing shown by FIG. It is sectional drawing for demonstrating the contact aspect of a bracket and a housing | casing. It is a figure which shows the modification of the side wall part of the housing | casing shown by FIG. It is a figure which shows another modification of the side wall part of the housing | casing shown by FIG.

  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 perspective view showing a battery pack according to the present embodiment. As shown in FIG. 1, the battery pack 1 includes a housing 2, a battery module 3, and bolts 4 (fastening members). The battery pack 1 is a device used as a vehicle battery such as a forklift. The battery pack 1 is accommodated in a predetermined battery accommodating portion.

  The housing | casing 2 is formed with metals, such as iron. The housing 2 has a rectangular box shape and houses the battery module 3. The housing 2 includes a bottom wall part 21, an upper wall part 22, a side wall part 23, a side wall part 24, a front wall part 25, and a rear wall part 26. The bottom wall portion 21, the upper wall portion 22, the side wall portion 23, the side wall portion 24, the front wall portion 25, and the rear wall portion 26 are integrated by welding or fastening by bolts (not shown). The side wall part 23 has the inner surface 23a (support surface). Details of the side wall 23 of the housing 2 will be described later.

  The battery module 3 is accommodated in the housing 2. The battery module 3 is fixed to the inner surface 23 a of the housing 2 by a plurality of bolts 4. In this example, two battery modules 3 are arranged in the first direction (X-axis direction), and the battery modules 3 are further stacked on each battery module 3. The number and arrangement of the battery modules 3 are not limited to this. The bolt 4 is a fastening member for fixing the battery module 3 to the inner surface 23a. In the present embodiment, the number of bolts 4 used for fixing one battery module 3 is eight, but is not limited thereto.

  FIG. 2 is a perspective view showing an appearance of the battery module shown in FIG. FIG. 3 is a view of the battery module shown in FIG. 2 as viewed from the housing side. As shown in FIGS. 2 and 3, the battery module 3 includes an array 5 and a restraining member 6.

  The array 5 includes a plurality of battery cells 11 arranged in the first direction, a plurality of cell holders 12, and an elastic member 13. The battery cell 11 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. In the present embodiment, the array 5 is configured by arranging the seven battery cells 11 and the elastic members 13 in the first direction. In the array 5, heat transfer plates may be arranged adjacent to the battery cells 11.

  The battery cell 11 is formed by, for example, housing an electrode assembly and an electrolytic solution in a hollow case having a substantially rectangular parallelepiped shape. A pair of electrode terminals are provided apart from each other on the top surface of the case. One of the electrode terminals is a positive electrode terminal connected to the positive electrode of the electrode assembly, and the other of the electrode terminals is a negative electrode terminal connected to the negative electrode of the electrode assembly. The battery cells 11, 11 adjacent to each other in the array 5 are arranged so that the positive electrode terminal and the negative electrode terminal are adjacent to each other, and the adjacent positive electrode terminal and the negative electrode terminal are electrically connected by the bus bar member 15. Connected in series.

  Each battery cell 11 is held by a cell holder 12 made of resin, for example. The cell holder 12 has a frame that fits to the bottom and side surfaces of the case of the battery cell 11.

  The elastic member 13 is a member used for the purpose of preventing the battery cell 11 and the like from being damaged by a restraining load when the battery cell 11 is expanded. The elastic member 13 is formed in a rectangular plate shape by, for example, urethane rubber sponge. In the present embodiment, the elastic member 13 is located at one end of the array 5 in the first direction. Examples of other forming materials of the elastic member 13 include ethylene propylene diene rubber (EPDM), chloroprene rubber, and silicon rubber. The elastic member 13 is not limited to rubber and may be a spring material or the like.

  The restraining member 6 restrains the array 5 along the first direction. More specifically, the restraining member 6 includes a bracket 61 (first bracket), a bracket 62 (second bracket), a plurality of bolts 63, and a plurality of nuts 64.

  The bracket 61 is disposed at one end of the array body 5 in the first direction. The bracket 61 is made of, for example, a steel material such as SS400, and the surface thereof is plated with zinc (Zn). As an example, the bracket 61 is formed in an L-shaped plate shape by a rectangular plate-shaped main body portion 61a and a rectangular plate-shaped fixing portion 61b. The main body portion 61 a is a portion for sandwiching the array body 5 in the first direction, and is disposed on the elastic member 13 positioned at one end of the array body 5. The main body 61a is provided with a plurality of insertion holes (not shown) through which the bolts 63 are inserted.

  The fixing portion 61b is a portion fixed to the inner surface 23a by the bolt 4, and extends from the main body portion 61a to the side opposite to the array body 5 along the first direction. The fixing portion 61b has a fixing surface 61f that is in contact with the inner surface 23a. The fixing portion 61b is provided with a plurality of insertion holes 61h (first insertion holes). The insertion hole 61h is a hole through which the bolt 4 is inserted. The insertion hole 61h is a round hole having a substantially circular shape. The insertion hole 61h penetrates the fixing portion 61b in the second direction (Y-axis direction). The plurality of insertion holes 61h are arranged along the third direction (Z-axis direction). In the present embodiment, the number of insertion holes 61h is four, but is not limited thereto.

  The bracket 62 is disposed at the other end of the array body 5 in the first direction. The bracket 62 is made of, for example, a steel material such as SS400, and the surface thereof is plated with zinc (Zn). As an example, the bracket 62 is formed in an L-shaped plate shape by a rectangular plate-shaped main body portion 62a and a rectangular plate-shaped fixing portion 62b. The main body 62a is a portion for sandwiching the array body 5 in the first direction, and is disposed on the battery cell 11 positioned at the other end of the array body 5. The main body portion 62a is provided with a plurality of insertion holes (not shown) through which the bolts 63 are inserted.

  The fixing portion 62b is a portion that is fixed to the inner surface 23a by the bolt 4, and extends from the main body portion 62a to the side opposite to the array body 5 along the first direction. The fixing portion 62b has a fixing surface 62f that is in contact with the inner surface 23a. The fixed portion 62b is provided with a plurality of insertion holes 62h (second insertion holes). The insertion hole 62h is a hole through which the bolt 4 is inserted. The insertion hole 62h is an elongated hole that has an oval shape extending in the first direction. The insertion hole 62h penetrates the fixing portion 62b in the second direction. The plurality of insertion holes 62h are arranged along the third direction. In the present embodiment, the number of insertion holes 62h is four, but is not limited thereto. The length D2 along the first direction of the insertion hole 62h is larger than the length D1 along the first direction of the insertion hole 61h.

  The bolt 63 and the nut 64 are made of metal such as iron. The bolt 63 is sequentially inserted through an insertion hole (not shown) of the bracket 62, a through hole (not shown) of each cell holder 12, and an insertion hole (not shown) of the bracket 61. The nut 64 is screwed to the end of the bolt 63 on the outside of the bracket 61 so as to fasten the bracket 61 and the bracket 62 to each other. Accordingly, the main body 61a and the main body 62a sandwich the array body 5 in the first direction, and a restraining load is applied to the array 5 (battery cell 11) via the bracket 61 and the bracket 62.

  Next, details of the side wall 23 of the housing 2 will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram illustrating a state in which the battery module is attached to the inner surface of the housing illustrated in FIG. 1. FIG. 5 is a diagram illustrating a state in which the battery module is removed from the inner surface of the housing illustrated in FIG. 4.

  As shown in FIGS. 4 and 5, the housing 2 includes a metal base 31 and a covering member 32 that covers the surface of the metal base 31. Specifically, the bottom wall portion 21, the upper wall portion 22, the side wall portion 23, the side wall portion 24, the front wall portion 25, and the rear wall portion 26 constituting the housing 2 are coated with a metal base 31 with a covering member 32. It is formed by doing. The metal substrate 31 is made of a steel material such as SS400, for example. The covering member 32 is a film formed by, for example, painting or metal plating. In the present embodiment, the covering member 32 is a film made of a paint mainly composed of an epoxy resin as a cationic paint. That is, the covering member 32 is formed by applying cationic electrodeposition to the metal substrate 31. As the cationic paint, a paint mainly composed of an acrylic resin can be used. A paint mainly composed of an epoxy resin has good anticorrosion properties, and a paint mainly composed of an acrylic resin has good weather resistance.

  The inner surface 23a is provided with a plurality of screw holes 23b and 23c. The screw holes 23b and 23c are holes for fixing the battery module 3 to the inner surface 23a. The bolt 4 is screwed into the screw holes 23b and 23c. More specifically, the screw hole 23b is a hole for fixing the fixing portion 61b of the bracket 61 to the inner surface 23a, and the screw hole 23c is a hole for fixing the fixing portion 62b of the bracket 62 to the inner surface 23a. The screw hole 23b is provided corresponding to the insertion hole 61h provided in the fixing portion 61b of the bracket 61. The screw hole 23 c is provided corresponding to the insertion hole 62 h provided in the fixing portion 62 b of the bracket 62. That is, in a state where the battery module 3 is attached to the inner surface 23a, the plurality of screw holes 23b are located in a portion overlapping the insertion hole 61h, and the plurality of screw holes 23c are located in a portion overlapping the insertion hole 62h. The bolt 4 is inserted into the insertion hole 61h and screwed into the screw hole 23b, whereby the fixing portion 61b is fixed to the side wall portion 23, and the bolt 4 is inserted into the insertion hole 62h and screwed into the screw hole 23c. As a result, the fixing portion 62 b is fixed to the side wall portion 23.

  The inner surface 23a includes a covered region Rc and a non-covered region Rm. The covering region Rc is a region where the surface of the metal substrate 31 is covered with the covering member 32. The uncovered region Rm is a region where the surface of the metal substrate 31 is not covered with the coating member 32 and the surface of the metal substrate 31 is exposed. Generally, when cationic electrodeposition coating is applied, the surface of the covering member 32 is smoother than the surface of the metal substrate 31. That is, the surface roughness of the covered region Rc is smaller than the surface roughness of the non-covered region Rm.

  The uncovered region Rm includes a portion where the screw hole 23b and the screw hole 23c are provided. That is, the fixing portion 61 b of the bracket 61 is fixed to the non-covering region Rm by the bolt 4. The fixing portion 62b of the bracket 62 is fixed to the non-covering region Rm by the bolt 4. More specifically, the non-covering region Rm includes a first non-covering region Rm1 to which the fixing portion 61b is fixed, and a second non-covering region Rm2 to which the fixing portion 62b is fixed. The first uncovered region Rm1 is larger than the fixed surface 61f of the fixed portion 61b. In other words, the first uncovered region Rm1 includes a portion C1 that is in contact with the fixed surface 61f. Thereby, when the fixing | fixed part 61b is fixed to 1st non-covering area | region Rm1, possibility that the fixing surface 61f will protrude from 1st non-covering area | region Rm1 is reduced. Similarly, the second non-covering region Rm2 is larger than the fixing surface 62f of the fixing portion 62b. In other words, the second uncovered region Rm2 includes a portion C2 that is in contact with the fixed surface 62f. Thereby, when the fixing | fixed part 62b is fixed to 2nd non-covering area | region Rm2, possibility that the fixing surface 62f will protrude from 2nd non-covering area | region Rm2 is reduced.

  Next, with reference to FIG. 6, the effect of the battery pack 1 is demonstrated. FIG. 6 is a cross-sectional view for explaining a contact mode between the bracket and the housing. FIG. 6A is a cross-sectional view illustrating a contact mode between the bracket and the housing in the present embodiment. b) is a cross-sectional view showing a contact mode between a bracket and a housing in a comparative example. FIGS. 6A and 6B show cross sections along the first direction around the bracket 61. Since the manner of contact between the bracket 62 and the housing 2 is the same, the description will be made using the bracket 61 here.

The battery module 3 is fixed to the housing 2 by brackets 61 and 62. When the battery pack 1 is mounted and used in a vehicle or the like, an impact may be applied to the battery pack 1. At this time, a force along the inner surface 23 a is applied to the battery module 3. If this force causes slippage between the fixed surfaces 61f and 62f and the inner surface 23a, a rotational force is applied to the bolt 4 and the bolt 4 may be loosened. In order to prevent such loosening of the bolt 4, the fastening axial force F of the bolt 4, the weight m of the battery module 3, the friction coefficient μ between the fixing surfaces 61 f and 62 f and the inner surface 23 a, and the number n of the bolts 4 are It needs to be designed to satisfy equation (1). The fastening axial force F is a value determined by the fastening torque and the specifications of the bolt 4. The acceleration g is the maximum acceleration that occurs in the battery module 3. The acceleration g applied to the battery module 3 is set to 50G according to UN transport regulations. The friction coefficient μ is a static friction coefficient, and a value measured by a measurement method defined in JIS K 7125 is used as the friction coefficient μ.

  As shown in FIG. 6B, in the battery pack of the comparative example, the fixing portion 61b of the bracket 61 is fixed to the covering region Rc forming the inner surface 23a by the bolt 4. By forming the covering member 32 on the surface of the metal substrate 31 by the cationic electrodeposition coating, the inner surface 23a is a smooth surface. That is, the surface roughness of the inner surface 23a in the covering region Rc is small. For this reason, the friction coefficient μ (static friction coefficient and dynamic friction coefficient) tends to be small.

  In such a case, in order to satisfy the equation (1), the fastening axial force F is increased, the weight m is decreased, the friction coefficient μ is increased, and the number n is increased. However, the weight m of the battery module 3 is about 20 kg, and the weight m cannot be changed. The fastening axial force F needs to be set so as not to exceed the yield strength and fracture strength of the bolt 4. For this reason, there is a limit in preventing loosening by increasing the fastening axial force F. Moreover, loosening can be suppressed by increasing the number n. However, the number n of bolts 4 is also limited due to restrictions such as mounting space.

  On the other hand, as shown in FIG. 6A, in the battery pack 1, the fixing portion 61b of the bracket 61 is fixed to the uncovered region Rm forming the inner surface 23a by the bolt 4. Since the inner surface 23a in the non-covering region Rm is the surface of the metal substrate 31 that is not covered by the covering member 32, the surface roughness of the inner surface 23a in the non-covering region Rm is greater than the surface roughness of the inner surface 23a in the covering region Rc. large. For this reason, compared with the battery pack of a comparative example, friction coefficient (micro | micron | mu) becomes large. That is, when the fixing portion 61b is fixed to the non-covering region Rm, the friction coefficient (static friction coefficient and dynamic friction coefficient) generated between the fixing portion 61b (fixing surface 61f) and the non-covering region Rm (inner surface 23a) is When the fixing portion 61b is fixed to the covering region Rc, the friction coefficient (static friction coefficient and dynamic friction coefficient) generated between the fixing portion 61b (fixing surface 61f) and the covering region Rc (inner surface 23a) is larger. Thereby, it becomes possible to suppress loosening of the bolt 4 without changing the fastening axial force F and the number n of the bolt 4.

  As described above, in the battery pack 1, the battery module 3 is fixed to the housing 2 by fixing the fixing portion 61 b of the bracket 61 and the fixing portion 62 b of the bracket 62 to the inner surface 23 a of the housing 2 by the bolt 4. Is done. The fixing portion 61b of the bracket 61 is fixed to the non-covering region Rm where the surface of the metal substrate 31 is exposed. When the fixing portion 61b is fixed to the non-covering region Rm, the friction coefficient generated between the fixing portion 61b and the non-covering region Rm is the same as that of the fixing portion 61b and the covering region when the fixing portion 61b is fixed to the covering region Rc. It is larger than the friction coefficient generated between Rc. For this reason, rather than fixing the fixing portion 61b of the bracket 61 to the covering region Rc, the fixing of the fixing portion 61b of the bracket 61 to the non-covering region Rm causes slippage between the fixing surface 61f and the inner surface 23a of the fixing portion 61b. It is suppressed. Further, the fixing portion 62 b of the bracket 62 is fixed to the non-covering region Rm by the bolt 4. Similarly to the fixing portion 61b, the slip between the fixing surface 62f and the inner surface 23a of the fixing portion 62b is suppressed. Thus, since not only the fixing part 61b of the bracket 61 but also the fixing part 62b of the bracket 62 is fixed to the non-covering region Rm, the sliding of the battery module 3 with respect to the inner surface 23a is suppressed. As a result, it is possible to suppress loosening of the bolts 4 without changing the fastening axial force and the number of the bolts 4.

  The length D2 along the first direction of the insertion hole 62h is larger than the length D1 along the first direction of the insertion hole 61h. That is, the insertion hole 62h is a long hole extending along the first direction. For this reason, even if the length along the first direction of the battery module 3 varies due to a manufacturing error or the like, the variation can be absorbed by the insertion hole 62h. Therefore, it becomes possible to improve the certainty of attachment of the battery module 3.

  In the covering region Rc, the surface of the metal substrate 31 is covered with the covering member 32. Since the covering member 32 formed by the cationic electrodeposition coating suppresses the generation of rust in the metal substrate 31, the generation of rust in the covering region Rc can be suppressed.

  The first uncovered region Rm1 includes a portion C1 that is in contact with the fixed surface 61f. Thereby, when the fixing | fixed part 61b is fixed to 1st non-covering area | region Rm1, possibility that the fixing surface 61f will protrude from 1st non-covering area | region Rm1 is reduced. Therefore, the coefficient of friction generated between the fixed portion 61b and the non-covering region Rm can be increased more reliably. Similarly, the second uncovered region Rm2 includes a portion C2 that is in contact with the fixed surface 62f. Thereby, when the fixing | fixed part 62b is fixed to 2nd non-covering area | region Rm2, possibility that the fixing surface 62f will protrude from 2nd non-covering area | region Rm2 is reduced. Therefore, the coefficient of friction generated between the fixed portion 62b and the non-covering region Rm can be increased more reliably.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the battery cell 11 may not be held by the cell holder 12. Further, the elastic member 13 may not be provided.

  Further, the insertion hole 62h provided in the fixing portion 62b of the bracket 62 may not be a long hole extending along the first direction. For example, the insertion hole 62h may have the same shape as the insertion hole 61h. In this case, the manufacture of the bracket 62 can be facilitated.

  The covering member 32 is not limited to a film formed by cationic electrodeposition coating. The covering member 32 only needs to have a surface roughness smaller than the surface roughness of the metal substrate 31. That is, the covering member 32 may be any member that can make the surface roughness of the covering region Rc smaller than the surface roughness of the non-covering region Rm.

  Further, the surface roughness of the uncovered region Rm may be further increased by processing. In this case, the friction coefficient μ between the fixed surfaces 61f and 62f and the inner surface 23a can be further increased.

  Further, the covering member 32 is not required to be provided in the portion C1, and the region where the covering member 32 is provided (covering region Rc) can be changed as appropriate.

  FIG. 7 is a view showing a modification of the side wall portion of the housing shown in FIG. As shown in FIG. 7, the side wall portion 23 of the modification is mainly different from the side wall portion 23 shown in FIG. 5 in that the non-covering region Rm does not include the second non-covering region Rm2. That is, the covering region Rc includes the portion C2, and the surface of the metal base 31 is covered with the covering member 32 in the portion C2 of the inner surface 23a. The screw hole 23 c is not covered with the covering member 32. In this case, the fixing portion 61 b of the bracket 61 is fixed to the non-covering region Rm by the bolt 4. On the other hand, the fixing portion 62 b of the bracket 62 is fixed to the covering region Rc by the bolt 4.

  When the battery pack 1 is used, the battery cell 11 may expand to increase the length of the battery module 3 along the first direction. The insertion hole 62h provided in the fixing portion 62b of the bracket 62 extends along the first direction. Therefore, the position along the first direction of the fixing portion 62b of the bracket 62 is adjusted by the length along the first direction of the insertion hole 62h with respect to the mounting position (screw hole 23c) of the bracket 62 on the inner surface 23a. Can be done. Since the fixing portion 62b of the bracket 62 is fixed to the covering region Rc, the fixing portion 62b of the bracket 62 is more slidable with respect to the inner surface 23a than the fixing portion 61b of the bracket 61. Thereby, even if the battery cell 11 expand | swells and the length along the 1st direction of the battery module 3 becomes large, the fixing | fixed part 62b of the bracket 62 can slide along a 1st direction, and the battery cell 11 Can be absorbed. That is, in the modified example, it is possible to suppress the loosening of the bolt 4 by the fixing portion 61b and to absorb the expansion of the battery cell 11 by the fixing portion 62b. As described above, in the modification, different functions are assigned to the fixing portion 61b and the fixing portion 62b, respectively.

  FIG. 8 is a view showing another modification of the side wall of the housing shown in FIG. As shown in FIG. 8, compared with the side wall part 23 shown in FIG. 5, in the side wall part 23 of another modified example, the first uncovered regions Rm <b> 1 adjacent in the third direction are integrated, and the third This is mainly different in that the second uncovered regions Rm2 adjacent in the direction are integrated. That is, one first uncovered region Rm1 is provided for the fixing portion 61b of the battery modules 3 adjacent in the third direction, and one fixing portion 62b of the battery module 3 adjacent in the third direction is provided. A second uncovered region Rm2 is provided. In this case, since the masking for providing the covering member 32 can be simplified, the production of the battery pack 1 can be simplified.

  Further, the entire inner surface 23a may be the uncovered region Rm. In this case, since it is not necessary to perform masking to provide the covering member 32, it is possible to simplify the manufacture of the battery pack 1.

  DESCRIPTION OF SYMBOLS 1 ... Battery pack, 2 ... Housing | casing, 3 ... Battery module, 4 ... Bolt (fastening member), 5 ... Array, 23 ... Side wall part, 23a ... Inner surface (support surface), 11 ... Battery cell, 31 ... Metal substrate 32 ... Cover member, 61 ... Bracket (first bracket), 61a ... Main body part, 61b ... Fixing part, 61f ... Fixing surface, 61h ... Insertion hole (first insertion hole), 62 ... Bracket (second bracket), 62a ... main body part, 62b ... fixed part, 62f ... fixed surface, 62h ... insertion hole (second insertion hole), D1 ... length, D2 ... length, Rc ... covered region, Rm ... non-covered region, Rm1 ... first 1 uncovered region, Rm2... Second uncovered region.

Claims (5)

A housing having a support surface;
A battery module housed in the housing;
A fastening member for fixing the battery module to the support surface;
With
The battery module includes an array having a plurality of battery cells arranged in a first direction, a first bracket disposed at one end of the array in the first direction, and the array in the first direction. A second bracket disposed at the other end,
The first bracket and the second bracket extend from the main body portion to the opposite side of the array body in the first direction, and extend from the body portion to the side opposite to the array body. A fixed portion to be fixed,
The housing includes a metal base and a covering member that covers a surface of the metal base,
The support surface includes a covered region covered by the covering member, and an uncovered region where the surface of the metal substrate is exposed,
When the fixing part is fixed to the non-covering area, the friction coefficient generated between the fixing part and the non-covering area is such that the fixing part and the covering are fixed when the fixing part is fixed to the covering area. Larger than the coefficient of friction that occurs between the area,
The battery pack, wherein the fixing portion of the first bracket is fixed to the uncovered region by the fastening member. The fixing portion of the first bracket is provided with a first insertion hole for inserting the fastening member,
The fixing portion of the second bracket is provided with a second insertion hole for inserting the fastening member,
The battery pack according to claim 1, wherein a length of the second insertion hole along the first direction is larger than a length of the first insertion hole along the first direction.   The battery pack according to claim 2, wherein the fixing portion of the second bracket is fixed to the covering region by the fastening member.   The battery pack according to claim 2, wherein the fixing portion of the second bracket is fixed to the uncovered region by the fastening member.   The battery pack according to any one of claims 1 to 4, wherein the covering member is a coating composed of a cationic paint.

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