Battery pack

Abstract

To obtain a battery pack having a cooling structure capable of suppressing wetting of battery cells due to condensation occurring in a cooler.SOLUTION: A battery pack 10 includes a plurality of battery cells 24 arranged along a first direction D1, and a first cooler 32 extending along the first direction D1 and disposed to the side of the plurality of battery cells 24. The battery pack 10 also includes a heat conductive member 40 disposed to the side of the plurality of battery cells 24 and interposed between the plurality of battery cells 24 and the first cooler 32. A bracket 50 is provided on the upper portion of the heat conductive member 40 to separate the upper end portion of the first cooler 32 from the plurality of battery cells 24, and the bracket 50 can guide condensation occurring at the upper end portion of the first cooler 32 to the heat conductive member 40 side.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a battery pack.

Background Art

[0002] Patent Document 1 discloses a cooling structure in which a cooler is disposed above a plurality of battery cells inside a battery pack. In this cooling structure, unevenness is provided on the surface of a partition wall sandwiched between the plurality of battery cells and the cooler, and this unevenness makes it difficult to cause dew condensation when cooling the battery pack.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to improve the cooling performance of a battery pack, it is conceivable to dispose a cooler on the side of a battery cell. In such a case, a structure for suppressing the battery cell from being wetted by dew condensation generated in the cooler is required.

[0005] In consideration of the above facts, an object of the present invention is to provide a battery pack having a cooling structure capable of suppressing the battery cell from being wetted by dew condensation generated in the cooler.

Means for Solving the Problems

[0006] The battery pack according to claim 1 of the present invention comprises: a plurality of battery cells arranged along a first direction; a cooler extending along the first direction and positioned to the side of the plurality of battery cells; a heat conductive member positioned to the side of the plurality of battery cells and interposed between the plurality of battery cells and the cooler; and a bracket provided on the upper part of the heat conductive member, which separates the upper end of the cooler from the plurality of battery cells and thereby guides condensation generated at the upper end toward the heat conductive member.

[0007] The battery pack according to claim 1 of the present invention comprises a plurality of battery cells arranged along a first direction. A cooler extending in the first direction is positioned on the side of the plurality of battery cells, and a heat conductive member is interposed between the plurality of battery cells and the cooler. This allows heat exchange to occur between the sides of the plurality of battery cells and the cooler via the heat conductive member, thereby cooling the plurality of battery cells.

[0008] Here, a bracket is provided at the top of the heat conduction member, separating the upper end of the cooler from the multiple battery cells. This bracket guides condensation generated at the upper end of the cooler towards the heat conduction member. This prevents the battery cells from getting wet due to condensation generated in the cooler. [Effects of the Invention]

[0009] As described above, the battery pack according to the present invention has the effect of suppressing the wetting of battery cells due to condensation generated in the cooler. [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view showing the internal structure of the battery pack according to this embodiment. [Figure 2] This is a cross-sectional view showing the state when the object is cut along line II-II in Figure 1. [Figure 3] This is a partially enlarged cross-sectional view showing a magnified view of the upper part of the battery cell shown in Figure 2. [Modes for carrying out the invention]

[0011] The battery pack 10 according to this embodiment will be described below with reference to Figures 1 to 3. Arrow D1, as shown in each figure, indicates the first direction of the battery module 20, and arrow D2 indicates the second direction of the battery module 20. The second direction D2 is perpendicular to the first direction D1.

[0012] (Overview) Figure 1 shows a side view of the battery pack 10 as seen from a second direction D1. As shown in this figure, the battery pack 10 consists of a box-shaped case 12 and a battery module 20 housed inside the case 12. The material that makes up the case 12 is not particularly limited. In one example of this embodiment, the case 12 is made of steel plate.

[0013] The battery module 20 includes a pair of end plates 22 arranged at a predetermined interval in a first direction D1, a plurality of battery cells 24 arranged between the pair of end plates 22, a cooler 30 for cooling the plurality of battery cells, and a heat conductive member 40 interposed between the plurality of battery cells 24 and the cooler 30.

[0014] Multiple battery cells 24 are arranged along a first direction D1, sandwiched between a pair of end plates 22. Each battery cell 24 is a rechargeable battery in the shape of a rectangular parallelepiped and has terminals 26 on its upper surface for wiring connections. The battery cells 24 can be of any type of battery, but as an example, they are composed of lithium-ion secondary batteries.

[0015] Furthermore, a buffer material 28 is placed between adjacent battery cells 24. The buffer material 28 absorbs the expansion or contraction of the battery cells 24 during charging and discharging.

[0016] The cooler 30 includes a first cooler 32 positioned to the side of the plurality of battery cells 24 and a second cooler 34 positioned below the plurality of battery cells 24.

[0017] The first cooler 32 has a thin box shape with the second direction D2 as the thickness direction, and a refrigerant flow path is formed inside the box-shaped space. Further, the first cooler 32 extends along the first direction D1 and is formed in a long shape. This first cooler 32 is arranged in a pair on both sides in the second direction D2 with respect to a plurality of battery cells 24 arranged along the first direction D1. Both end portions of each first cooler 32 in the first direction D1 are connected to a pair of end plates 22 via brackets not shown in the figure.

[0018] The second cooler 34 has a thin box shape with the height direction as the thickness direction, and a refrigerant flow path is formed inside the box-shaped space. Further, the second cooler 34 extends along the first direction D1 and is formed in a long shape. This second cooler 34 is arranged below with respect to a plurality of battery cells 24 arranged along the first direction D1. Both end portions of the second cooler 34 in the first direction D1 are connected to a pair of end plates 22 via brackets not shown in the figure.

[0019] That is, the first cooler 32 and the second cooler 34 connect between the pair of end plates 22 in the first direction D1.

[0020] FIG. 2 shows a cross section of the battery module 20 cut along the second direction D2. As shown in this figure, plate-like heat conduction members 40 are arranged on the sides and below of the plurality of battery cells 24. The heat conduction member 40 is interposed between the plurality of battery cells 24 and the cooler 30 (the first cooler 32 and the second cooler 34), and heat exchange is performed between the plurality of battery cells 24 and the cooler 30 through the heat conduction member 40.

[0021] (Cooling structure of the battery pack) The above-mentioned first cooler 32 corresponds to the "cooler" in the present invention. Hereinafter, details of the cooling structure including the first cooler 32 arranged on the side of the plurality of battery cells 24, the heat conduction member 40 interposed between the plurality of battery cells 24 and the first cooler 32, and the bracket 50 provided on the heat conduction member 40 will be described.

[0022] The first cooler 32 has an inner panel 36 arranged facing a plurality of battery cells 24 and an outer panel 38 arranged outside the inner panel 36.

[0023] The inner panel 36 is composed of a metal plate-like member and has a vertical wall portion 36A extending in the height direction (vertical direction), an upper wall portion 36B extending substantially horizontally from the upper end portion of the vertical wall portion 36A toward the plurality of battery cells 24, and a lower wall portion 36C extending substantially horizontally from the lower end portion of the vertical wall portion 36A toward the plurality of battery cells 24. The inner panel 36 has an open cross-section in a rectangular shape (U-shaped) with the cross-section along the second direction D2 open to the side of the plurality of battery cells 24, formed by the vertical wall portion 36A, the upper wall portion 36B, and the lower wall portion 36C.

[0024] In this inner panel 36, the upper wall portion 36B is arranged above the plurality of battery cells 24 and is arranged to cover the end portions of the upper surfaces of the respective battery cells 24 in plan view. The lower wall portion 36C is arranged below the plurality of battery cells 24 and is fixed to the lower surfaces of the respective battery cells 24. As a result, the end portions in the width direction (second direction D2) of the plurality of battery cells 24 are arranged inside the open cross-section formed by the vertical wall portion 36A, the upper wall portion 36B, and the lower wall portion 36C. Also, the end portion of the inner panel 36 in the first direction D1 is connected to the end plate 22 via a bracket not shown.

[0025] The outer panel 38 is composed of a metal plate-like member and is arranged outside the inner panel 36. The outer panel 38 has an open cross-section in a substantially hat shape with the cross-section along the second direction D2 open to the side of the inner panel 36, and has a shallow bathtub shape as a whole. The outer panel 38 has a flange-shaped outer peripheral portion joined to the vertical wall portion 36A of the inner panel 36, forming a box-shaped refrigerant space S between the inner panel 36 and the outer panel 38. Also, although not shown, refrigerant pipes constituting the refrigerant flow path are arranged in this refrigerant space S.

[0026] Due to the configuration of the inner panel 36 and outer panel 38 described above, the first cooler 32 has a thin, box-like shape. Furthermore, the first cooler 32 applies a predetermined restraining pressure to the multiple battery cells 24 along the first direction D1 by connecting a pair of end plates 22 in the first direction D1. Thus, the first cooler 32 has a cooling function that cools the multiple battery cells 24 from the side and also constitutes a restraining member that restrains the multiple battery cells 24.

[0027] The heat conduction member 40 is positioned on the side of the multiple battery cells 24, between the sides of the multiple battery cells 24 and the vertical wall portion 36A of the inner panel 36. The heat conduction member 40 is a plate-shaped member made of metal or resin with excellent thermal conductivity. The heat conduction member 40 is formed in a rectangular shape with the second direction D2 as the thickness direction, and extends in a long length along the first direction D1.

[0028] Here, the upper end of the heat conduction member 40 is formed in a mountain shape that convex upward when viewed from the side (view in the second direction D2). As a result, two inclined surfaces 40A are formed on the upper surface of the heat conduction member 40, which are inclined downward from the inside to the outside (from the middle to the end) in the first direction D1. These inclined surfaces 40A are provided to guide the condensation that has been guided from the bracket 50 (described later) to the heat conduction member 40 to the end of the battery module 20 along the first direction D1.

[0029] A waterproof bracket 50 is provided at the upper end of the heat conduction member 40, extending along the first direction D1. The bracket 50 is erected upward from the upper end of the heat conduction member 40 and is positioned to separate the upper end of the first cooler 32 from the plurality of battery cells 24.

[0030] As shown in Figure 3, the bracket 50 is joined to the upper end of the heat conduction member 40 and has a first wall portion 52 extending upward, a second wall portion 54 extending substantially horizontally from the upper end of the first wall portion 52 toward the multiple battery cells 24, a third wall portion 56 extending upward from the end of the second wall portion 54, and a fourth wall portion 58 extending substantially horizontally from the upper end of the third wall portion 56 toward the first cooler 32.

[0031] The second wall portion 54 is positioned below the upper wall portion 36B of the inner panel 36, which is the upper end of the first cooler 32, and covers the ends of the upper surfaces of the multiple battery cells 24 from above. Furthermore, the upper wall portion 36B of the inner panel 36 is positioned inside the rectangular open cross-section formed by the second wall portion 54, the third wall portion 56, and the fourth wall portion 58. Therefore, when condensation occurs on the upper wall portion 36B of the inner panel 36 during cooling of the battery pack 10, the falling condensation is caught by the second wall portion 54 of the bracket 50 and does not fall onto the upper surface of the battery cell 24. The condensation that falls from the upper wall portion 36B is then guided along the second wall portion 54 to the inclined surface 40A of the heat conduction member 40. This prevents the upper surface of the battery cell 24 and the terminals 26 from getting wet due to condensation generated in the first cooler 32.

[0032] Furthermore, in this embodiment, the upper surface of the second wall portion 54 of the bracket 50, that is, the surface 54A facing the upper wall portion 36B of the inner panel 36, is inclined downward from the inside to the outside (towards the heat conductive member 40) in the second direction D2. As a result, condensation that falls from the upper wall portion 36B onto the opposing surface 54A of the second wall portion 54 is not retained on the second wall portion 54 but is well guided towards the heat conductive member 40.

[0033] (Mechanism of action and effect) As described above, the battery pack 10 according to this embodiment comprises a plurality of battery cells 24 arranged along a first direction D1. A first cooler 32 extending in the first direction D1 is positioned to the side of the plurality of battery cells 24, and a heat conductive member 40 is interposed between the plurality of battery cells 24 and the first cooler 32. This allows heat exchange to occur between the sides of the plurality of battery cells 24 and the first cooler 32 via the heat conductive member 40, thereby cooling the plurality of battery cells 24 from the side.

[0034] Here, a bracket 50 is provided on the upper part of the heat conduction member 40, separating the upper end of the first cooler 32 from the multiple battery cells 24. This bracket 50 guides the condensation generated at the upper end (upper wall portion 36B) of the first cooler 32 towards the heat conduction member 40. This prevents the battery cells 24 from getting wet due to condensation generated in the first cooler 32. [supplementary explanation]

[0035] Although embodiments of the present invention have been described above, the present invention is not limited to the configurations of the embodiments described above. The embodiments described above can be modified as appropriate without departing from the spirit of the present invention.

[0036] In the above embodiment, the heat conduction member is made of a single plate-shaped member, but the present invention is not limited thereto. A configuration in which multiple plate-shaped heat conduction members are arranged at predetermined intervals may also be used. In this case, there may be multiple heat conduction members formed in an elongated shape with the height direction as the longitudinal direction, and the multiple heat conduction members may be arranged at predetermined intervals along the first direction D1, forming a stripe shape when viewed from the second direction D2. In such a configuration, condensation generated at the upper end (upper wall portion 36B) of the first cooler 32 is guided to the side of the multiple heat conduction members via the bracket 50 and flows downward through the gaps between the heat conduction members. [Explanation of Symbols]

[0037] 10 battery packs 24 battery cells 32 1st cooler (cooler) 40 Heat conductive material 50 brackets D1 First direction

Claims

[Claim 1] Multiple battery cells arranged along a first direction, A cooler extending along the first direction and positioned laterally to the plurality of battery cells, A heat conductive member is positioned to the side of the plurality of battery cells and interposed between the plurality of battery cells and the cooler, A bracket provided on the upper part of the heat conductive member, which separates the upper end of the cooler from the plurality of battery cells, thereby guiding the condensation generated at the upper end towards the heat conductive member, A battery pack equipped with the following features.

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