Battery support structure

Abstract

Regarding the battery retention structure, the goal is to efficiently increase rigidity while also efficiently improving cooling performance for the battery. [Solution] A battery holding structure is disclosed, comprising a battery support member that extends in the vehicle width direction and the vehicle longitudinal direction and supports the battery on its upper side, wherein the battery support member is an extruded material having a truss-shaped closed cross section when viewed in the vehicle width direction, and the closed space formed by the truss-shaped closed cross section forms a refrigerant flow path.

Description

Technical Field

[0001] The present disclosure relates to a battery holding structure.

Background Art

[0002] There is known a battery case having a double-bottom structure with an inner bottom plate portion and an outer bottom plate portion spaced apart in the vertical direction from each other, and a heat sink is disposed on the inner bottom plate portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the prior art as described above requires a plurality of members such as an inner bottom plate portion, an outer bottom plate portion, a heat sink, a lower frame, etc., and it is not possible to efficiently enhance the cooling performance for the battery while efficiently enhancing the rigidity of the battery case.

[0005] Therefore, on one aspect, the present disclosure aims to efficiently enhance the cooling performance for the battery while efficiently enhancing the rigidity with respect to the battery holding structure.

Means for Solving the Problems

[0006] On one aspect, it includes a battery support member that extends in the vehicle width direction and the vehicle longitudinal direction and supports the battery on the upper surface side. The battery support member is an extruded material having a closed cross-section in a truss shape when viewed in the vehicle width direction. A battery holding structure is provided in which a closed space formed by the closed cross-section in the truss shape forms a refrigerant flow path.

Effects of the Invention

[0007] In one respect, this disclosure makes it possible to efficiently increase the rigidity of the battery holding structure while also efficiently improving the cooling performance of the battery. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view showing the overall battery holding structure of this embodiment. [Figure 2] This is a schematic perspective view showing the entire battery support component. [Figure 3] This is a cross-sectional view showing the relationship between the battery support member and the battery (cell), and is a cross-sectional view taken from the XZ plane. [Figure 3A] This is an enlarged view of section Q3 in Figure 3. [Figure 4] This is a diagram illustrating the cooling system. [Figure 5] This is a perspective view showing the inlet flow path configuration near the center frame, and is a partial perspective view of Figure 1. [Figure 6] This is a perspective view showing the inlet flow path configuration in the battery support member, and is a perspective view showing a part of Figure 2. [Figure 7] This is a cross-sectional view showing the inlet flow path configuration near the center frame. [Figure 8] This is a perspective view showing the outlet flow path configuration near the side frame, and is a partial perspective view of Figure 1. [Figure 9] This is a diagram illustrating a further characteristic configuration of this embodiment, and is a cross-sectional view showing a preferred configuration of busbars that electrically connect the battery cells. [Modes for carrying out the invention]

[0009] The following describes each embodiment in detail with reference to the attached drawings. Note that the dimensional ratios in the drawings are merely examples and are not exhaustive. Furthermore, shapes and other details in the drawings may be partially exaggerated for illustrative purposes. Also, for clarity, in some cases, only a portion of parts with the same attribute are assigned reference numerals in the drawings.

[0010] Figure 1 is a schematic perspective view showing the entire battery holding structure 1 of this embodiment. Figure 2 is a schematic perspective view showing the entire battery support member 70. Figure 1 shows three orthogonal axes (XYZ) in a right-handed coordinate system. The same coordinate system is shown in Figure 2 and subsequent figures. The X direction corresponds to the vehicle's longitudinal direction, the Y direction corresponds to the vehicle's width direction, and the Z direction corresponds to the vertical direction.

[0011] The battery holding structure 1 may have symmetry with respect to the XZ plane passing through the center in the Y direction. Below, the configuration of one side in the Y direction with respect to the XZ plane passing through the center in the Y direction will be mainly described, but the other side may be similar. Hereinafter, "outside in the Y direction" refers to the outside (outside the vehicle) with respect to the center in the Y direction.

[0012] The battery holding structure 1 is applicable to vehicles equipped with an electric motor 8 (see Figure 4) for vehicle drive. The vehicle may be a hybrid vehicle, an electric vehicle, or the like.

[0013] The battery holding structure 1 includes a battery support member 70.

[0014] The battery support member 70 is supported by the center frame 30 on the center side in the Y direction and by the side frame 32 on the outer side in the Y direction. The battery support member 70 may be joined to the center frame 30 by welding or the like, and to the side frame 32 by welding or the like.

[0015] The center frame 30 and the side frame 32, together with the battery support member 70, form a part of the vehicle body. They have a box cross-section when viewed in the X direction. The center frame 30 and the side frame 32 may each be extruded members having the same cross-section at any X-direction position. Note that the box cross-sectional shape of the center frame 30 may be larger than the box cross-sectional shape of the side frame 32. The side frame 32 may be a member separate from the side sill or may be realized by the side sill. Note that the side frame 32 is also referred to as a rocker EA (Energy Absorption) and may have a function of receiving an X-direction load (for example, a load during a collision) from a front side member (not shown) and absorbing the impact.

[0016] As shown in FIG. 2, the battery support member 70 extends in the X direction and the Y direction. The battery support member 70 may extend along the XY plane. As shown in FIG. 1, the battery support member 70 supports the battery 5 on the upper surface side. Note that the battery 5 functions as a power source for an electric motor 8 (see FIG. 4) for vehicle driving. The battery 5 is a high-voltage battery and may be, for example, 400 V or more. As shown in FIG. 1, the battery 5 has a cell arrangement in which a plurality of cells 51 arranged in a row in the X direction are arranged in a plurality of rows in the Y direction. However, the cell arrangement itself is arbitrary, including the number of rows, size, arrangement pitch, and the like. In particular, in this embodiment, as will be described later, since the cells 51 can be cooled regardless of which part of the battery support member 70 they are arranged in, the cells can be freely selected and laid out, including the cell shape.

[0017] FIG. 3 is a cross-sectional view showing the relationship between the battery support member 70 and the battery 5 (cells 51), and is a cross-sectional view by the XZ plane. FIG. 3A is an enlarged view of the Q3 portion of FIG. 3.

[0018] In this embodiment, the battery support member 70 has a truss-shaped closed cross-section when viewed in the Y direction. Here, a truss shape refers to a combination of triangles. In this embodiment, the battery support member 70 is an extruded material having the same truss-shaped closed cross-section at any position in the Y direction. For example, the battery support member 70 may be formed by extruding an aluminum alloy material.

[0019] The closed section of the truss shape, when viewed in the Y direction, has the form of a combination of a first triangle 81 and a second triangle 82 that are alternately connected in the X direction. The first triangle 81 has its vertex on the upper side, and the second triangle 82 has its upper side on the same side as the upper vertex of the first triangle 81. The first triangle 81 and the second triangle 82 are inverted in their orientation. The first triangle 81 and the second triangle 82 are alternately connected in the X direction in a manner that they share a hypotenuse. The plate thickness (plate thickness in the cross section viewed in the Y direction) of the wall portion (wall portion) that forms the closed section of the truss shape is constant, but may vary locally.

[0020] In this embodiment, the first triangle 81 and the second triangle 82 are isosceles triangles, but they may be other triangular shapes. For example, the first triangle 81 and the second triangle 82 may be other shapes as long as their upper and lower sides are horizontal and their heights are the same. Also, the first triangle 81 and the second triangle 82 may be equilateral triangles.

[0021] Thus, in this embodiment, the battery support member 70 has a truss-shaped closed cross-section, which allows it to have high rigidity. This makes it possible to eliminate or simplify other reinforcing members that extend in the Y direction. Furthermore, because the center frame 30 has a box-shaped cross-section, even when subjected to a load in the Y direction from the side, the center frame 30 collapses, reducing the amount of deformation of the battery support member 70 itself. In other words, the center frame 30 can absorb loads in the Y direction (including loads during collisions, etc.), and effectively protect the battery 5 from loads in the Y direction from the side.

[0022] In this embodiment, the closed space S2 formed by the truss-shaped closed cross section forms the refrigerant flow path 80. The closed space S2 is a closed space surrounded by the second triangle 82. That is, the portion of the truss-shaped closed cross section of the battery support member 70 that forms the second triangle 82 forms the refrigerant flow path 80. The battery support member 70 is an extruded material in the Y direction, and the closed space S2 (and the refrigerant flow path 80) basically extends in the Y direction with an equal cross section. Therefore, the refrigerant in the refrigerant flow path 80 can flow in the Y direction.

[0023] Furthermore, the refrigerant flow path 80 is formed for each second triangle 82, and the number of refrigerant flow paths 80 formed corresponds to the number of second triangles 82 aligned along the X direction. Hereinafter, any single individual refrigerant flow path 80 will also be referred to as "one refrigerant flow path 80".

[0024] Thus, according to this embodiment, the rigidity of the battery holding structure 1 can be efficiently increased by the truss-shaped closed cross section, while the cooling performance of the battery holding structure 1 for the battery 5 can be efficiently improved by the refrigerant flow path 80 formed by the truss-shaped closed cross section.

[0025] In this embodiment, the portion corresponding to the upper side of the second triangle 82 forms a planar upper surface portion 71 as the second triangle 82 is connected in the X direction. In this way, in this embodiment, the portion of the battery support member 70 corresponding to the upper side of the second triangle 82 forms the battery 5 mounting portion (i.e., the upper surface portion 71 that supports the battery 5). As a result, the refrigerant flowing in the refrigerant flow path 80 comes into direct contact with substantially the entire upper surface portion 71 of the battery support member 70 (strictly speaking, the entire portion excluding the portion corresponding to the vertex of the first triangle 81). Therefore, according to this embodiment, the battery 5 can be efficiently cooled through the entire upper surface of the battery support member 70.

[0026] Here, with reference to Figure 4, we will outline the cooling system 100 equipped with a refrigerant flow path 80.

[0027] Figure 4 shows an overview of the cooling system 100.

[0028] The cooling system 100 includes a refrigerant path 11 that circulates through a condenser 2, evaporator 3, and chiller 4 for an air conditioning unit (not shown), a refrigerant path 12 that circulates through the chiller 4 and battery 5, and a refrigerant path 13 that circulates through a radiator 6, power supply system 7, and electric motor 8.

[0029] The power supply system 7 may include an inverter and / or a converter. The radiator 6 and condenser 2 are located at the front of the vehicle and cool the refrigerant by receiving airflow while driving.

[0030] In this embodiment, the refrigerant flow path 80 forms part of the refrigerant passage 12 and circulates in a manner that cools the battery 5.

[0031] Note that the cooling system 100 shown in Figure 4 is merely an example, and the other configurations of the cooling system 100 are arbitrary, as long as it includes a refrigerant flow path 80 for cooling the battery 5.

[0032] Next, with reference to Figures 5 to 8, an example of the configuration related to the refrigerant flow path 80 of the refrigerant passage 12 will be described.

[0033] Figure 5 is a perspective view showing the inlet channel configuration near the center frame 30, and is a perspective view of a portion of Figure 1. Figure 6 is a perspective view showing the inlet channel configuration in the battery support member 70, and is a perspective view of a portion of Figure 2. Figure 7 is a cross-sectional view showing the inlet channel configuration near the center frame 30. Figure 8 is a perspective view showing the outlet channel configuration near the side frame 32, and is a perspective view of a portion of Figure 1.

[0034] In this embodiment, as an example, the inlet passage 88 for the refrigerant passage 80 is provided near the center frame 30, and the outlet passage 89 from the refrigerant passage 80 is provided near the side frame 32. However, in a modified example, the opposite may be true. That is, the inlet passage may be provided near the side frame 32, and the outlet passage may be provided on the center frame 30.

[0035] Specifically, in this embodiment, an inlet channel forming member 880 is provided near the center frame 30, as shown in Figure 5, to form an inlet channel 88. The inlet channel forming member 880 is positioned relative to the vertical wall 31 of the center frame 30 and the upper surface 71 of the battery support member 70. The inlet channel forming member 880 forms an inlet channel 88 between the vertical wall 31 of the center frame 30 and the upper surface 71 of the battery support member 70, as shown in Figure 7. The inlet channel forming member 880 extends in the X direction with a uniform cross-section, and in this case, the inlet channel 88 extends in the X direction with a uniform cross-section. However, the cross-sectional shape of the inlet channel 88 does not need to be uniform; for example, it can be modified in various ways, such as tapering or widening, to control the flow velocity. The same applies to the outlet channel 89. The inlet channel forming member 880 may be joined to the vertical wall 31 of the center frame 30 and the upper surface 71 of the battery support member 70 by welding or the like.

[0036] Furthermore, as shown in Figure 6, a communication hole 72 is formed at the end of the upper surface portion 71 of the battery support member 70 on the center frame 30 side. The communication hole 72 is provided in such a manner that it opens into the outlet passage 89. That is, the communication hole 72 is provided in a position that overlaps with the outlet passage 89 when viewed in the vertical direction. The refrigerant passage 80 communicates with the inlet passage 88 through the communication hole 72. One communication hole 72 may be provided for each refrigerant passage 80 along the X direction. Alternatively, multiple communication holes 72 may be provided for a single refrigerant passage 80.

[0037] With this inlet channel configuration, the refrigerant (e.g., cooling water) supplied to the inlet channel 88 enters the refrigerant channel 80 through the communication hole 72, flows through the refrigerant channel 80 in the Y direction, and can flow to the outlet channel 89, which will be described later.

[0038] Similarly, near the side frame 32, as shown in Figure 8, an outlet channel forming member 890 is provided to form an outlet channel 89. The outlet channel forming member 890 is positioned in the same manner as the inlet channel forming member 880, relative to the vertical wall 33 of the side frame 32 and the upper surface 71 of the battery support member 70. Similar to the inlet channel forming member 880, the outlet channel forming member 890 forms an outlet channel 89 between the vertical wall 33 of the side frame 32 and the upper surface 71 of the battery support member 70. In this case, the outlet channel 89 extends in the X direction with an equal cross-section. The outlet channel forming member 890 may be joined to the vertical wall 33 of the side frame 32 and the upper surface 71 of the battery support member 70 by welding or the like.

[0039] Furthermore, a communication hole (not shown) similar to the communication hole 72 shown in Figure 6 is formed at the end of the upper surface portion 71 of the battery support member 70 on the side frame 32 side.

[0040] With this outlet channel configuration, the refrigerant (e.g., cooling water) supplied to the refrigerant channel 80 can flow to the outlet channel 89 through the communication hole.

[0041] In this embodiment, the refrigerant can be flowed in the Y direction from the inlet passage 88 across the entire upper surface 71 of the battery support member 70, and the battery 5 on the upper surface 71 can be efficiently cooled.

[0042] Figure 9 is an explanatory diagram of a further characteristic configuration of this embodiment, and is a cross-sectional view showing a preferred configuration of a busbar 95 that electrically connects the cells 51 of the battery 5.

[0043] In this embodiment, busbars 95 are provided between adjacent cells 51 in the X direction. Adjacent cells 51 in the X direction are electrically connected via the corresponding busbars 95. The busbars 95 are provided on both the positive and negative sides of the cell 51, respectively.

[0044] In this embodiment, the busbar 95 is thermally connected to the upper surface 71 of the battery support member 70. Specifically, when viewed in the X direction, the busbar 95 has a side portion 950 and a bottom portion 951 that form an L-shaped cross section (see also Figures 5, 8, etc.). The side portion 950 is joined to the side electrodes (not shown) of the cell 51. The bottom portion 951 faces the battery support member 70 along its plane. The bottom portion 951 may be joined to the battery support member 70 via an insulating layer (not shown). The bottom portion 951 may have a dimension in the X direction that is longer than the distance between the centers of two adjacent cells 51. The bottom portion 951 can have a relatively large area when viewed from above. This efficiently increases the area of ​​heat transfer with the upper surface 71 of the battery support member 70. As a result, according to this embodiment, not only the battery 5 but also the busbar 95 can be efficiently cooled by the coolant flowing through the coolant channel 80.

[0045] Although each embodiment has been described in detail above, the invention is not limited to any particular embodiment, and various modifications and changes are possible within the scope described in the claims. Furthermore, it is possible to combine all or more of the components of the embodiments described above.

[0046] For example, in the embodiment described above, the battery 5 is placed directly on the upper surface 71 of the battery support member 70, but it may also be placed via a layer or material having high thermal conductivity, such as a thermal sheet.

[0047] Furthermore, in the embodiment described above, the first triangle 81 has a vertex on its upper side, and the second triangle 82 has an upper side at the same height as the upper vertex of the first triangle 81. However, the height of the second triangle 82 does not have to be the same as the upper vertex of the first triangle 81, as long as the upper side of the second triangle 82 is on the same side as the upper vertex of the first triangle 81. For example, in order to make the thickness of the sides of the upper and lower triangles equal, the position of the vertex may be moved away from the side when the upper vertex of the first triangle 81 and the upper side of the second triangle 82 intersect. Alternatively, the sides and vertices of the triangles may be moved away from each other when they intersect. [Explanation of Symbols]

[0048] 1 Battery holding structure, 5 Battery, 70 Battery support member, 71 Top surface, S2 Closed space, 80 Refrigerant flow path, 95 Bus bar

Claims

1. It includes a battery support member that extends in the vehicle width direction and the vehicle longitudinal direction, and supports the battery on its upper side. The aforementioned battery support member is an extruded material having a truss-shaped closed cross-section when viewed in the vehicle width direction. The closed space formed by the truss-shaped closed cross section forms a refrigerant flow path in the battery holding structure.

2. The closed cross-section of the truss shape, when viewed in the vehicle width direction, has a form in which first and second triangles are alternately arranged in the vehicle's longitudinal direction. The first triangle has a vertex on its upper side, and the second triangle has an upper side on the same side as the vertex. The battery holding structure according to claim 1, wherein the portion of the battery support member relating to the upper side of the second triangle forms an upper surface portion that supports the battery.

3. The battery holding structure according to claim 2, wherein the closed space that forms the refrigerant flow path among the closed spaces formed by the truss-shaped closed cross section is the closed space surrounded by the second triangle.

4. The battery support member is thermally connected to the busbar that is electrically connected to the battery. The battery holding structure according to any one of claims 1 to 3, wherein the bus bar has an L-shaped cross-section when viewed in the longitudinal direction of the vehicle, and one surface forming the L-shaped cross-section faces the battery support member along its surface.

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