JP2018010807A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack in which liquid is hard to intrude into a housing when a battery pack is arranged so that a side wall of the housing extends along the horizontal plane.SOLUTION: A battery pack 10 according to an embodiment includes: a housing 2 having an opening 2a; a lid 4 for closing the opening 2a; and a battery module M housed in the housing 2. The housing 2 includes a bottom wall 20 and a side wall 22. The side wall 22 has a first edge 22e connected to the bottom wall 20 and a second edge 22f for defining the opening 2a. An external surface 22a of the side wall 22 at the first edge 22e and the bottom wall 20 are connected by a welded part w1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery pack.

  A battery pack is known that includes a battery module having a plurality of battery cells and a housing that houses the battery module (see Patent Document 1). This housing has a bottom wall and a side wall standing from the bottom wall, and an opening is defined by the upper end of the side wall. The opening is closed by a lid. This battery pack is mounted on a vehicle such as an electric vehicle.

JP 2011-54353 A

  By the way, the battery pack may be mounted on the vehicle with the opening of the housing facing sideways. In that case, the upper side wall of the housing extends along a horizontal plane. Here, for example, when a liquid such as water is applied to the battery pack by car washing, the liquid accumulates on the upper side wall of the casing. In this case, if the seal between the opening of the housing and the lid is insufficient, the accumulated liquid may enter the housing from between the opening of the housing and the lid.

  An object of one aspect of the present invention is to provide a battery pack in which liquid does not easily enter the casing when the battery pack is arranged so that the side wall of the casing extends along a horizontal plane.

  A battery pack according to an aspect of the present invention includes a housing having an opening, a lid that closes the opening, and a battery module that is housed in the housing. The housing includes a bottom wall and a side wall. And the side wall includes a first edge connected to the bottom wall and a second edge defining the opening, and the outer surface of the side wall at the first edge, The bottom wall is connected by a weld.

  In this battery pack, the outer surface of the side wall at the first edge and the bottom wall are connected by a weld. Therefore, the outer surface of the side wall bends outward as the distance from the first edge portion increases due to distortion of the welded portion. For example, the outer surface of the side wall after welding can be inclined outward with respect to the reference plane orthogonal to the bottom wall from the first edge toward the second edge. Alternatively, by bending the outer surface of the side wall before welding to the inside of the housing in advance with respect to the reference surface, the outer surface of the side wall after welding is changed from the first edge toward the second edge to the reference surface. It can also be parallel. When such a battery pack is arranged so that the side wall of the housing extends along a horizontal plane, even if the liquid accumulates on the side wall, the liquid hardly flows toward the second edge. Therefore, since it is difficult for the liquid to reach between the opening of the housing and the lid, it is difficult for the liquid to enter the housing.

  The outer surface of the side wall may be inclined outward with respect to a reference plane orthogonal to the bottom wall from the first edge toward the second edge.

  When such a battery pack is arranged so that the side wall of the housing extends along a horizontal plane, even if the liquid accumulates on the side wall, the liquid flows from the second edge toward the first edge by gravity.

  The battery pack may further include a seal member disposed between the opening and the lid.

  In this case, even if the seal between the opening and the lid of the housing is insufficient, the liquid does not easily reach between the opening and the lid, so that the liquid does not easily enter the housing.

  The lid may have a protruding portion that protrudes outward from an extended surface of the outer surface of the side wall.

  In this case, liquid may normally accumulate in the space between the protruding portion of the lid and the outer surface of the side wall. However, in the battery pack, since it is difficult for the liquid to reach between the opening and the lid, even if the lid has a protruding portion, it is difficult for the liquid to accumulate in the space between the outer surface of the side wall and the protruding portion. Therefore, it is difficult for the liquid to enter the housing.

  The bottom wall has a protruding portion protruding outward from an extended surface of the outer surface of the side wall, and the outer surface of the side wall and the protruding portion of the bottom wall are connected by the welding portion. Also good.

  In this case, the connection strength between the bottom wall and the side wall can be improved.

  According to one aspect of the present invention, it is possible to provide a battery pack in which liquid does not easily enter the casing when the battery pack is arranged so that the side wall of the casing extends along a horizontal plane.

It is a perspective view showing typically a part of vehicles provided with a battery pack concerning an embodiment. FIG. 2 is a cross-sectional view of a part of the vehicle along the line II-II in FIG. 1. It is a perspective view which shows typically an example of the battery module with which the battery pack which concerns on embodiment is provided. It is an exploded perspective view showing typically a part of battery pack concerning an embodiment. It is a figure which shows typically a part of housing | casing with which the battery pack which concerns on embodiment is provided. It is a figure which shows typically a part of housing | casing which concerns on a 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.

  FIG. 1 is a perspective view schematically showing a part of a vehicle including the battery pack according to the embodiment. FIG. 2 is a cross-sectional view of a part of the vehicle along the line II-II in FIG. FIG. 3 is a perspective view schematically illustrating an example of a battery module included in the battery pack according to the embodiment.

  The vehicle 1 shown in FIGS. 1 and 2 can be an industrial vehicle such as a forklift. The vehicle 1 can include a battery pack 10 and a vehicle body 50 to which the battery pack 10 is fixed.

  The battery pack 10 includes a housing 2 having an opening 2a, a lid 4 that closes the opening 2a, and a plurality (for example, eight) of battery modules M housed in the housing 2.

  Each battery module M has a plurality of battery cells 61 arranged in one direction, as shown in FIG. Each battery cell 61 is held by a battery holder 62 forming a frame. The battery cell 61 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, for example, and houses an electrode assembly in a case. The battery cell 61 is provided with a positive electrode terminal and a negative electrode terminal.

  Each battery cell 61 is arranged so that terminals having different polarities are adjacent to each other, and are electrically connected in series by a bus bar 63. A pair of end plates 64 capable of restraining the plurality of battery cells 61 in the arrangement direction are respectively provided at the arrangement ends of the battery cells 61. Each end plate 64 is provided with a bracket 65 for fixing the battery module M to the housing 2 or the lid 4. The battery module M is fixed to the housing 2 or the lid 4 via a bracket 65 by a fastening member such as a bolt. Each bracket 65 may be integral with each end plate 64.

  Hereinafter, the battery pack 10 will be described in detail with reference to FIGS. 1, 2, and 4. FIG. 4 is an exploded perspective view schematically showing a part of the battery pack according to the embodiment. An XYZ orthogonal coordinate system is shown in FIGS.

  As described above, the battery pack 10 includes the housing 2 having the opening 2a and the lid 4 that closes the opening 2a. The opening 2a has, for example, a rectangular shape. The housing 2 has a bottomed cylindrical shape, for example. The battery pack 10 may include a seal member 6 disposed between the opening 2 a and the lid 4. The seal member 6 has a ring shape surrounding the opening 2a, for example. The seal member 6 is made of, for example, a foam.

  The lid 4 is a metal plate such as an iron plate, for example. A plurality of battery modules M are fixed to the lid 4. The lid 4 can be fixed to the housing 2 by a plurality of fastening members B. The fastening member B is, for example, a bolt. The lid 4 is formed with holes 4h through which the respective fastening members B are inserted. The housing 2 is formed with holes 2h for screwing the respective fastening members B together. Each fastening member B is screwed into the hole 2 h of the housing 2 in a state of being inserted through the hole 4 h of the lid 4. The seal member 6 is located between the hole 2h of the housing 2 and the opening 2a.

  The housing 2 includes a bottom wall 20 and a plurality of side walls 22, 24, 26, 28. The bottom wall 20 is disposed to face the opening 2a. The side walls 22 and 24 are opposed to each other. The side wall 24 is fixed to the vehicle body 50. The side walls 26 and 28 are arranged to face each other. Each of the bottom wall 20 and the side walls 22, 24, 26, and 28 is a metal plate such as an iron plate, and has, for example, a rectangular shape when viewed from the thickness direction. In the present embodiment, the plurality of battery modules M are fixed to the bottom wall 20, but may be fixed to any one of the side walls 22, 24, 26, and 28.

  The side wall 22 is connected to the bottom wall 20 by a welded portion w1. The side wall 24 is connected to the bottom wall 20 by a welded portion w2. The side wall 26 is connected to the side wall 22 by the welded part w3, connected to the bottom wall 20 by the welded part w4, and connected to the side wall 24 by the welded part w5. The side wall 28 is connected to the side wall 22 by a welded part w6, connected to the bottom wall 20 by a welded part w7, and connected to the side wall 24 by a welded part w8. The welds w1 and w2 are fillet welds, for example, and the welds w3 to w8 are square welds, for example.

  The side wall 22 has a first edge 22e connected to the bottom wall 20 and a second edge 22f that defines the opening 2a. The first edge 22 e is welded to the bottom wall 20, but the second edge 22 f is not welded to the lid 4. The side wall 24 has a first edge 24e connected to the bottom wall 20 and a second edge 24f that defines the opening 2a. The first edge 24 e is welded to the bottom wall 20, but the second edge 24 f is not welded to the lid 4. The second edge portions 22f and 24f may constitute a flange portion.

  The side wall 22 has an outer surface 22a and an inner surface 22b. The outer surface 22a in the 1st edge part 22e of the side wall 22 and the bottom wall 20 are connected by the welding part w1. Although the inner surface 22b and the bottom wall 20 in the 1st edge part 22e of the side wall 22 are not welded, you may weld.

  In the present embodiment, the bottom wall 20 has a protruding portion 20 p that protrudes outward from the extended surface of the outer surface 22 a of the side wall 22. In this case, the outer surface 22a of the side wall 22 and the protruding portion 20p of the bottom wall 20 are connected by the welded portion w1. Thereby, the welding part w1 can be made into a fillet weld part.

  In the present embodiment, the outer surface 22a of the side wall 22 is inclined outward with respect to the reference plane P orthogonal to the bottom wall 20 (for example, the inner surface of the bottom wall 20) from the first edge 22e to the second edge 22f. doing. The reference plane P is a horizontal plane, for example. The outer surface 22a of the side wall 22 may be a flat surface or a curved surface. When the outer surface 22a of the side wall 22 is a curved surface, the outer surface 22a of the side wall 22 is gradually curved outward with respect to the reference plane P from the first edge 22e toward the second edge 22f. Such a curved outer surface 22 a is formed by, for example, welding the side wall 24 to the bottom wall 20, welding the side wall 22 to the bottom wall 20, and then welding the side walls 26, 28 to the bottom wall 20 and the side walls 22, 24. Can be obtained.

  The side wall 24 has an outer surface 24a and an inner surface 24b. The inner surface 24b of the first edge 24e of the side wall 24 and the bottom wall 20 are connected by a welded portion w2. The outer surface 24a of the first edge 24e of the side wall 24 and the bottom wall 20 are not welded, but may be welded.

  The lid 4 may have a protruding portion 4 p that protrudes outward from the extended surface of the outer surface 22 a of the side wall 22. When the outer surface 22a of the side wall 22 is a curved surface, the extended surface of the outer surface 22a is a surface extending in the tangential direction at the edge of the outer surface 22a.

  FIG. 5 is a diagram schematically illustrating a part of the housing included in the battery pack according to the embodiment. As shown in FIG. 5, when the length of the side wall 22 from the first edge 22e to the second edge 22f is L and the thickness of the side wall 22 is T, the displacement of the outer surface 22a at the second edge 22f. The amount D is, for example, 0 or more and L / 600T or less. The displacement amount D is the difference between the position of the outer surface 22a at the first edge 22e and the position of the outer surface 22a at the second edge 22f in the direction parallel to the bottom wall 20 (the direction orthogonal to the reference plane P). . The displacement amount D is, for example, 0 or more and 0.5 mm or less. The thickness T of the side wall 22 is, for example, not less than 1.2 mm and not more than 8.0 mm. The length L of the side wall 22 is, for example, not less than 120 mm and not more than 350 mm.

  In the battery pack 10 of the present embodiment, the outer surface 22a of the side wall 22 and the bottom wall 20 at the first edge 22e are connected by the welded portion w1. Therefore, the outer surface 22a of the side wall 22 bends outward as the distance from the first edge portion 22e increases due to distortion of the welded portion w1. Thereby, the outer surface 22a of the side wall 22 after welding can be inclined outward with respect to the reference plane P orthogonal to the bottom wall 20 from the first edge 22e toward the second edge 22f. When such a battery pack 10 is arranged so that the side wall 22 of the housing 2 extends along a horizontal plane, even if liquid such as water from a car wash or the like accumulates on the side wall 22, for example, the second edge portion 22f due to gravity. To the first edge 22e. Since the welded portion w <b> 1 is formed between the bottom wall 20 and the first edge portion 22 e of the side wall 22, it is difficult for the liquid to enter the housing 2.

  When the seal member 6 is disposed between the opening 2a and the lid 4, even if the seal between the opening 2a and the lid 4 is insufficient, the opening 2a and the lid 4 of the housing 2 Since it is difficult for the liquid to reach between them, it is difficult for the liquid to enter the housing 2.

  If the lid 4 has a protruding portion 4p that protrudes outward from the extended surface of the outer surface 22a of the side wall 22, normally, there is a possibility that liquid will accumulate in the space between the outer surface 22a of the side wall 22 and the protruding portion 4p. There is. However, in the battery pack 10 of the present embodiment, since it is difficult for the liquid to reach between the opening 2a of the housing 2 and the lid 4, the outer surface 22a of the side wall 22 even if the lid 4 has the protruding portion 4p. The liquid is unlikely to collect in the space between the protrusion 4p and the protruding portion 4p. Therefore, it is difficult for the liquid to enter the housing 2.

  The bottom wall 20 has a protruding portion 20p that protrudes outward from the extended surface of the outer surface 22a of the side wall 22, and the outer surface 22a of the side wall 22 and the protruding portion 20p of the bottom wall 20 are connected by a welded portion w1. In this case, the connection strength between the bottom wall 20 and the side wall 22 can be improved.

  FIG. 6 is a diagram schematically illustrating a part of the housing according to the modification. The housing shown in FIG. 6A includes a bottom wall 120 instead of the bottom wall 20, and the housing 2 except that the bottom wall 120 and the outer surface 22a of the side wall 22 are connected by a welded portion w11. The same configuration is provided. The end surface of the bottom wall 120 is flush with the outer surface 22 a of the side wall 22. In this case, the welding part w11 is a butt welding part. The housing shown in FIG. 6B includes a bottom wall 220 instead of the bottom wall 20, and the housing 2 except that the bottom wall 220 and the outer surface 22a of the side wall 22 are connected by a welded portion w21. The same configuration is provided. The end surface of the bottom wall 220 is located inside the extended surface of the outer surface 22 a of the side wall 22 and is flush with the inner surface 22 b of the side wall 22. In this case, the welded part w21 is a corner welded part. When the welded portion (for example, the welded portion w1) is a fillet welded portion, the thickness of the welded portion can be increased compared to the butt welded portion (for example, the welded portion w11) or the corner welded portion (for example, the welded portion w21). It is easy to increase the strength against the plate thickness.

  In any case shown in FIGS. 6A and 6B, the outer surface 22a of the side wall 22 bends outward due to distortion of the welded portion w11 and the welded portion w21. Therefore, as in the case 2 described above, in any case shown in FIGS. 6A and 6B, it is difficult for liquid to enter the case.

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

  For example, by bending the outer surface 22a of the side wall 22 before welding to the inside of the housing 2 with respect to the reference plane P in advance, the outer surface 22a of the side wall 22 after welding is changed from the first edge 22e to the second edge. It can also be parallel to the reference plane P toward 22f. In this case, the liquid accumulated on the side wall 22 does not move due to gravity. Therefore, it is difficult for the liquid to flow toward the second edge 22f. Therefore, it is difficult for the liquid to reach between the opening 2 a of the housing 2 and the lid 4, so that it is difficult for the liquid to enter the housing 2.

  2 ... casing, 2a ... opening, 4 ... lid, 4p, 20p ... projecting portion, 6 ... sealing member, 20, 120, 220 ... bottom wall, 22 ... side wall, 22a ... outer surface, 22e ... first edge, 22f ... 2nd edge part, 10 ... battery pack, M ... battery module, P ... reference plane, w1, w11, w21 ... welding part.

Claims (5)

A housing having an opening;
A lid that closes the opening;
A battery module housed in the housing;
With
The housing includes a bottom wall and a side wall,
The side wall has a first edge connected to the bottom wall, and a second edge defining the opening,
The battery pack in which the outer surface of the said side wall in the said 1st edge part and the said bottom wall are connected by the welding part.   2. The battery pack according to claim 1, wherein the outer surface of the side wall is inclined outward with respect to a reference surface orthogonal to the bottom wall from the first edge toward the second edge.   The battery pack according to claim 1, further comprising a seal member disposed between the opening and the lid.   The battery pack according to claim 1, wherein the lid has a protruding portion that protrudes outward from an extended surface of the outer surface of the side wall. The bottom wall has a protruding portion protruding outward from an extended surface of the outer surface of the side wall;
The battery pack according to any one of claims 1 to 4, wherein the outer surface of the side wall and the protruding portion of the bottom wall are connected by the welded portion.

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