Battery pack

Abstract

To provide a battery pack which can freely control cooling efficiency of each of a plurality of battery cells, in a cooling design for more uniformly cooling the battery cells.SOLUTION: A battery pack comprises: a plurality of battery cells 11 stacked on each other; and a plate member 31 thermally connected to the plurality of battery cells 11. The plate member 31 includes inner walls 47 which define a coolant passage 40 where a coolant circulates. The inner walls 47 are provided with uneven parts 46 whose shapes vary in a flow direction of the coolant in the coolant passage 40.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This invention relates to a battery pack.

Background Art

[0002] For example, International Publication No. 2019 / 150705 (Patent Document 1) discloses a power supply device including a battery unit composed of a plurality of battery cells and a cooling plate that is thermally coupled to the battery cells and dissipates the thermal energy of the battery cells. A refrigerant passage for circulating a refrigerant is provided inside the cooling plate.

[0003] Further, Japanese Patent Translation Publication No. 2017-534143 (Patent Document 2) discloses a flat cooling plate for a secondary battery. Inside the cooling plate for a secondary battery, a plurality of cooling portions are provided separately from each other along its longitudinal direction. A plurality of reinforcing ribs are provided on the inner surface of the cooling portion.

[0004] Also, Chinese Utility Model Publication No. 213816250 (Patent Document 3) discloses a battery core heat dissipation module including a water-cooling plate. At least one passage is opened inside the water-cooling plate. A plurality of heat dissipation teeth are installed in the passage.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] As disclosed in Patent Documents 1 to 3 described above, a battery pack is known that includes a cell stack composed of a plurality of stacked battery cells, a cooling plate is connected to the cell stack, and a cooling mechanism is provided with a refrigerant passage in the cooling plate. However, due to various factors such as the stacking position of the battery cells in the cell stack, the position of the battery cells in the flow direction of the refrigerant, and the temperature environment around the battery cells, it is difficult to cool the plurality of battery cells evenly. For this reason, a method for freely controlling the cooling efficiency of each battery cell is required.

[0007] Therefore, an object of the present invention is to solve the above problems, and in a cooling design aimed at cooling a plurality of battery cells more evenly, to provide a battery pack capable of freely controlling the cooling efficiency of each battery cell.

Means for Solving the Problems

[0008] [1] A battery pack comprising a plurality of battery cells to be stacked and a plate member thermally connected to the plurality of battery cells, the plate member including an inner wall that defines a refrigerant passage through which the refrigerant flows, and the inner wall has a concave shape and / or a convex shape with respect to an opening formed by the refrigerant passage, and uneven portions whose shape changes in the flow direction of the refrigerant in the refrigerant passage are provided.

[0009] According to the battery pack configured in this way, by providing uneven portions on the inner wall that defines the refrigerant passage and changing the shape of the uneven portions in the flow direction of the refrigerant, the contact area between the refrigerant flowing through the refrigerant passage and the inner wall is changed. Thereby, in a cooling design aimed at cooling a plurality of battery cells more evenly, the cooling efficiency of each battery cell can be freely controlled.

[0010] [2] The refrigerant passage includes a first passage region and a second passage region located downstream of the first passage region in the refrigerant flow direction. The concavo-convex portion is provided such that the surface area of the inner wall in the second passage region is larger than the surface area of the inner wall in the first passage region per unit distance in the refrigerant flow direction in the refrigerant passage. The battery pack according to [1].

[0011] According to the battery pack configured as described above, since the second passage region is located downstream of the first passage region in the refrigerant flow direction, relatively high-temperature refrigerant flows through the second passage region, and relatively low-temperature refrigerant flows through the first passage region. In this case, by providing the concavo-convex portion such that the surface area of the inner wall in the second passage region is larger than the surface area of the inner wall in the first passage region, the cooling efficiency of the battery cell facing the second passage region can be enhanced.

[0012] [3] The battery pack includes a cell stack body composed of a plurality of the battery cells stacked in a predetermined direction. The refrigerant passage includes a third passage region facing an end portion of the cell stack body in the predetermined direction and a fourth passage region facing an intermediate portion of the cell stack body in the predetermined direction. The concavo-convex portion is provided such that the surface area of the inner wall in the fourth passage region is larger than the surface area of the inner wall in the third passage region per unit distance in the refrigerant flow direction in the refrigerant passage. The battery pack according to [1] or [2].

[0013] According to the battery pack configured as described above, since the battery cells arranged in the intermediate portion of the cell stack body are more difficult to dissipate heat than the battery cells arranged at the end portion of the cell stack body, they become high-temperature. In this case, by providing the concavo-convex portion such that the surface area of the inner wall in the fourth passage region facing the intermediate portion of the cell stack body is larger than the surface area of the inner wall in the third passage region facing the end portion of the cell stack body, the cooling efficiency of the intermediate portion of the cell stack body can be enhanced.

[0014] [4] A case body having side portions, an electronic component unit housed in the case body, a first cell stack formed by a plurality of stacked battery cells and housed in the case body at a position adjacent to the side portions, and a second cell stack formed by a plurality of stacked battery cells and housed in the case body at a position adjacent to the electronic component unit. The refrigerant passage includes a fifth passage region facing the first cell stack and a sixth passage region facing the second cell stack. The uneven portion is provided such that, per unit distance in the flow direction of the refrigerant in the refrigerant passage, the surface area of the inner wall in the sixth passage region is larger than the surface area of the inner wall in the fifth passage region. The battery pack according to any one of [1] to [3].

[0015] According to the battery pack configured as described above, since the second cell stack is arranged adjacent to the electronic component unit which is a heat-generating body, it becomes relatively hot, and since the first cell stack is arranged adjacent to the side portion of the case body, it becomes relatively cold. In this case, by providing the uneven portion such that the surface area of the inner wall in the sixth passage region facing the second cell stack is larger than the surface area of the inner wall in the fifth passage region facing the first cell stack, the cooling efficiency of the second cell stack can be enhanced.

[0016] [5] The refrigerant passage includes a plurality of passage regions that extend parallel to each other and are connected in order from the upstream side to the downstream side of the refrigerant flow. The shape of the uneven portion does not change in the flow direction of the refrigerant in the refrigerant passage in each passage region and is different from each other among the plurality of passage regions. The battery pack according to any one of [1] to [4].

[0017] According to the battery pack configured as described above, by using extrusion molding, a refrigerant passage including a plurality of passage regions with changing uneven shapes can be easily provided in the plate member.

Effects of the Invention

[0018] As described above, according to the present invention, in a cooling design aimed at cooling a plurality of battery cells more evenly, it is possible to provide a battery pack capable of freely controlling the cooling efficiency of each battery cell.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0020] Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

[0021] (Embodiment 1) FIG. 1 is an exploded perspective view of a battery pack according to Embodiment 1 of the present invention. FIG. 2 is a perspective view showing a battery cell constituting the battery pack in FIG. 1. FIGS. 3 and 4 are cross-sectional views showing the battery pack in FIG. 1. The cross-section of the battery pack shown in FIG. 3 corresponds to the cross-section of the battery pack viewed in the arrow direction on line III-III in FIG. 1, and the cross-section of the battery pack shown in FIG. 4 corresponds to the cross-section of the battery pack viewed in the arrow direction on line IV-IV in FIG. 3.

[0022] Referring to FIGS. 1 to 4, the battery pack 100 is used as a driving power source for vehicles such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0023] In this specification, for the sake of convenience in explaining the structure of the battery pack 100, an axis extending in the stacking direction of a plurality of battery cells 11 described later and in the horizontal direction is referred to as the "Y-axis", an axis extending in a direction perpendicular to the Y-axis and in the horizontal direction is referred to as the "X-axis", and an axis extending in the vertical direction is referred to as the "Z-axis".

[0024] First, the overall structure of the battery pack 100 will be described. The battery pack 100 has a plurality of battery cells 11. The plurality of battery cells 11 are stacked in the Y-axis direction. The battery cell 11 is a lithium-ion battery. The battery cell 11 is rectangular and has a thin rectangular parallelepiped shape. The plurality of battery cells 11 are stacked such that the Y-axis direction becomes the thickness direction of the battery cell 11.

[0025] The battery cell 11 has an exterior body 12. The exterior body 12 is formed of a rectangular parallelepiped-shaped housing and forms the exterior of the battery cell 11. An electrode body and an electrolytic solution are accommodated in the exterior body 12.

[0026] The exterior body 12 has a first side surface 13, a second side surface 14, a top surface 15, and a bottom surface 16. Each of the first side surface 13 and the second side surface 14 is composed of a plane orthogonal to the Y-axis. The first side surface 13 and the second side surface 14 face opposite sides in the Y-axis direction. Each of the first side surface 13 and the second side surface 14 has the largest area among the plurality of side surfaces of the exterior body 12.

[0027] Each of the top surface 15 and the bottom surface 16 is composed of a plane orthogonal to the Z-axis. The top surface 15 faces upward. The bottom surface 16 faces downward. A gas discharge valve 17 for discharging the gas to the outside of the exterior body 12 when the internal pressure of the exterior body 12 becomes a predetermined value or more due to the gas generated inside the exterior body 12 is provided on the top surface 15.

[0028] The battery cell 11 further has electrode terminals 18 in which a positive electrode terminal 18P and a negative electrode terminal 18N are paired. The electrode terminals 18 are provided on the top surface 15. The positive electrode terminal 18P and the negative electrode terminal 18N are provided apart from each other in the X-axis direction. The positive electrode terminal 18P and the negative electrode terminal 18N are provided on both sides of the gas discharge valve 17 in the X-axis direction, respectively.

[0029] Among the battery cells 11 adjacent to each other in the Y-axis direction, the first side surfaces 13 face each other, and the second side surfaces 14 face each other and are stacked. As a result, in the Y-axis direction in which the plurality of battery cells 11 are stacked, the positive electrode terminals 18P and the negative electrode terminals 18N are arranged alternately. Between the battery cells 11, 11 adjacent to each other in the Y-axis direction, the positive electrode terminals 18P and the negative electrode terminals 18N arranged in the Y-axis direction are connected to each other by a bus bar (not shown). The plurality of battery cells 11 are electrically connected in series with each other.

[0030] The cell stack 10 (10A, 10B) is composed of a plurality of battery cells 11 stacked in the Y-axis direction. The cell stack 10 has a rectangular parallelepiped shape. As a typical example, the length of the cell stack 10 in the Y-axis direction is larger than the length of the cell stack 10 in the Z-axis direction and larger than the length of the cell stack 10 in the X-axis direction. The cell stack 10A and the cell stack 10B are arranged side by side in the X-axis direction with a gap therebetween.

[0031] The battery pack 100 further has a case body 21. The case body 21 as a whole is composed of a box having a rectangular parallelepiped appearance. A plurality of battery cells 11 are accommodated inside the case body 21 (internal space 70).

[0032] The case body 21 has a plate member 31, a case side portion 23, a case top portion 24, and a case bottom portion 22. The plate member 31, together with the case side portion 23 and the case top portion 24, partitions and forms the internal space 70. The case bottom portion 22 is disposed at the bottom of the case body 21.

[0033] The plate member 31 is made of a plate material in which the Z-axis direction is the thickness direction and extends parallel to the X-axis - Y-axis plane. The case side portion 23 rises upward from the upper surface of the plate member 31 and forms an opening at its tip. The case top portion 24 faces the plate member 31 across the internal space 70 in the Z-axis direction. The case top portion 24 closes the opening formed by the upper end portion of the case side portion 23.

[0034] The case body 21 is formed of metal. The plate member 31 is formed of a different type of metal from the case side portion 23 and the case bottom portion 22. The thermal conductivity of the metal forming the plate member 31 is larger than the thermal conductivity of the metal forming the case side portion 23 and the case bottom portion 22. As an example, the plate member 31 is formed of aluminum, and the case side portion 23 and the case bottom portion 22 are formed of (steel plate).

[0035] The plurality of battery cells 11 are placed on the plate member 31. The plate member 31 is thermally connected to the plurality of battery cells 11. The plate member 31 is connected to the plurality of battery cells 11 so that heat transfer is possible between the plurality of battery cells 11 and the plate member 31. A heat transfer member 25 is inserted between the bottom surface 16 of the battery cell 11 and the plate member 31. The heat transfer member 25 may be composed of an adhesive material (adhesive) or a non - adhesive material.

[0036] The plurality of battery cells 11 are restrained by the case side portions 23 at both ends in the Y - axis direction. The case side portions 23 apply a restraining force (compressive force) in the Y - axis direction to the plurality of battery cells 11.

[0037] Note that the case body 21 may be configured such that the internal space 70 is partitioned by the case side portions 23, the case top portion 24, and the case bottom portion 22. In this case, the plate member 31 may be connected to the case bottom portion 22 from the outside of the internal space 70.

[0038] The heat generated by the plurality of battery cells 11 is radiated to the outside through the refrigerant flowing inside the plate member 31. Hereinafter, a more specific structure of the plate member 31 will be described.

[0039] The plate member 31 has an inner wall 47. The inner wall 47 defines a refrigerant passage 40 through which the refrigerant flows. The refrigerant is a fluid capable of transferring the heat generated by the battery cell 11 to the outside, and may be a liquid or a gas. The refrigerant passage 40 extends in the plane (X - axis - Y - axis plane) in which the plate member 31 extends. The refrigerant passage 40 extends in the vertical direction facing the plurality of battery cells 11.

[0040] The refrigerant passage 40 includes a plurality of passage regions 41 (41p, 41q, 41r, 41s). The passage regions 41p, 41q, 41r, and 41s are arranged in order from the upstream side to the downstream side of the refrigerant flow in the refrigerant passage 40. Each passage region 41 of the passage regions 41p, 41q, 41r, and 41s extends in the Y-axis direction. The passage regions 41p, 41q, 41r, and 41s meander along the X-axis direction while alternately reversing and extending in the +Y-axis direction and the -Y-axis direction.

[0041] The passage regions 41p and 41q face the cell stack 10A in the vertical direction. The passage regions 41r and 41s face the cell stack 10B in the vertical direction.

[0042] The inner wall 47 is provided with uneven portions 46. The uneven portions 46 form a concave shape and a convex shape with respect to the opening formed by the refrigerant passage 40. The uneven portions 46 are provided so as to increase the surface area of the inner wall 47. The uneven portions 46 are provided on the upper surface of the inner wall 47 forming the refrigerant passage 40. The refrigerant passage 40 is located on the opposite side of the plurality of battery cells 11 (internal space 70) with the uneven portions 46 interposed therebetween in the Z-axis direction. When the plate member 31 is cut by a plane (X-axis - Z-axis plane) orthogonal to the refrigerant flow in the refrigerant passage 40, the uneven portions 46 form a comb shape. The uneven portions 46 are composed of a plurality of ribs arranged at intervals in the X-axis direction. Each rib forms a convex shape protruding in the -Z-axis direction and extending in the Y-axis direction, and a concave shape recessed in the +Z-axis direction and extending in the Y-axis direction is formed between the ribs adjacent in the X-axis direction.

[0043] The shape of the uneven portions 46 changes in the flow direction of the refrigerant in the refrigerant passage 40. With such a configuration, the contact area between the refrigerant flowing through the refrigerant passage 40 and the inner wall 47 provided with the uneven portions 46 can be changed, and the efficiency of heat transfer from the plate member 31 to the refrigerant can be adjusted. Thereby, in a cooling design aimed at cooling the plurality of battery cells 11 more evenly, the cooling efficiency of each battery cell 11 can be freely controlled.

[0044] More specifically, the shape of the uneven portion 46 changes at the boundary between the passage region 41p and the passage region 41q located on the downstream side of the refrigerant flow in the refrigerant passage 40 with respect to the passage region 41p, changes at the boundary between the passage region 41q and the passage region 41r located on the downstream side of the refrigerant flow in the refrigerant passage 40 with respect to the passage region 41q, and changes at the boundary between the passage region 41r and the passage region 41s located on the downstream side of the refrigerant flow in the refrigerant passage 40 with respect to the passage region 41r. The shape of the uneven portion 46 does not change in each of the passage regions 41 of the passage region 41p, the passage region 41q, the passage region 41r, and the passage region 41s.

[0045] The uneven portion 46 is provided such that the surface area of the inner wall 47 in the passage region 41 located on the downstream side of the refrigerant flow in the refrigerant passage 40 is larger than the surface area of the inner wall 47 in the passage region 41 located on the upstream side of the refrigerant flow in the refrigerant passage 40 per unit distance in the flow direction of the refrigerant in the refrigerant passage 40.

[0046] The number of ribs forming the uneven portion 46 in the passage region 41q is larger than the number of ribs forming the uneven portion 46 in the passage region 41p. Thereby, the surface area of the inner wall 47 in the passage region 41q is larger than the surface area of the inner wall 47 in the passage region 41p per unit distance in the flow direction of the refrigerant in the refrigerant passage 40. The number of ribs forming the uneven portion 46 in the passage region 41r is larger than the number of ribs forming the uneven portion 46 in the passage region 41q. Thereby, the surface area of the inner wall 47 in the passage region 41r is larger than the surface area of the inner wall 47 in the passage region 41q per unit distance in the flow direction of the refrigerant in the refrigerant passage 40. The number of ribs forming the uneven portion 46 in the passage region 41s is larger than the number of ribs forming the uneven portion 46 in the passage region 41r. Thereby, the surface area of the inner wall 47 in the passage region 41s is larger than the surface area of the inner wall 47 in the passage region 41r per unit distance in the flow direction of the refrigerant in the refrigerant passage 40.

[0047] The refrigerant receives heat from the plurality of battery cells 11 while flowing through the refrigerant passage 40. Therefore, as the refrigerant moves from the upstream side to the downstream side of the refrigerant flow in the refrigerant passage 40, the temperature of the refrigerant rises, and there is a possibility that the battery cells 11 are not cooled evenly. In contrast, by providing the uneven portion 46 such that the surface area of the inner wall 47 in the passage region 41 located on the downstream side of the refrigerant flow is larger than the surface area of the inner wall 47 in the passage region 41 located on the upstream side of the refrigerant flow, heat transfer from the plate member 31 to the refrigerant flowing through the refrigerant passage 40 is promoted in the passage region 41 located on the downstream side of the refrigerant flow. Thereby, the plurality of battery cells 11 can be cooled more evenly.

[0048] Further, the shape of the uneven portion 46 does not change in the flow direction of the refrigerant in the refrigerant passage 40 in each of the passage regions 41 of the passage region 41p, the passage region 41q, the passage region 41r, and the passage region 41s, and is different from each other among the passage region 41p, the passage region 41q, the passage region 41r, and the passage region 41s. With such a configuration, it becomes possible to configure the plate member 31 from an extruded material of a metal such as aluminum.

[0049] FIG. 5 is a cross-sectional view showing a modified example of the uneven portion provided on the plate member in FIG. 4. Referring to FIG. 5, in this modified example, the uneven portion 46 has an arc-shaped concave shape with respect to the opening formed by the refrigerant passage 40. The curvature of the arc forming the uneven portion 46 in the passage region 41q is larger than the curvature of the arc forming the uneven portion 46 in the passage region 41p. Thereby, in the unit distance in the flow direction of the refrigerant in the refrigerant passage 40, the surface area of the inner wall 47 in the passage region 41q is larger than the surface area of the inner wall 47 in the passage region 41p.

[0050] Also with such a configuration, heat transfer from the plate member 31 to the refrigerant flowing through the refrigerant passage 40 can be further promoted in the passage region 41q disposed on the downstream side of the refrigerant flow.

[0051] In addition, in this embodiment, the case where the shape of the uneven portion 46 changes intermittently (at regular intervals along the flow direction of the refrigerant in the refrigerant passage 40) has been described, but the present invention is not limited to this. The shape of the uneven portion in the present invention may change continuously in the flow direction of the refrigerant in the refrigerant passage. Further, in a cooling design aimed at cooling a plurality of battery cells more evenly, in addition to the surface area of the inner wall, the opening area of the refrigerant passage may be further adjusted.

[0052] (Embodiment 2) FIG. 6 is a cross-sectional view showing a battery pack according to Embodiment 2 of the present invention. FIG. 6 corresponds to FIG. 3 in Embodiment 1. FIG. 7 is a cross-sectional view showing the battery pack as viewed in the arrow direction on the line VII-VII in FIG. 6. FIG. 8 is a cross-sectional view showing the battery pack as viewed in the arrow direction on the line VIII-VIII in FIG. 6. FIG. 9 is a cross-sectional view showing the battery pack as viewed in the arrow direction on the line IX-IX in FIG. 6.

[0053] The battery pack in the present embodiment basically has the same structure as the battery pack 100 in Embodiment 1. Hereinafter, the description of the overlapping structure will not be repeated.

[0054] Referring to FIGS. 6 to 9, the battery pack in the present embodiment includes a plurality of battery cells 11 and plate members 31 (31A, 31B, 31C). A cell stack 10 is constituted by a plurality of battery cells 11 laminated in the Y-axis direction. The plate members 31A, 31B, and 31C are arranged in the Y-axis direction, and the plate members 31 adjacent to each other in the Y-axis direction are connected. Each of the plate members 31 of the plate members 31A, 31B, and 31C is made of an extruded material of a metal such as aluminum.

[0055] In the plate members 31 (31A, 31B, 31C), a refrigerant passage 40 extending in the Y-axis direction is formed. The refrigerant passage 40 includes a plurality of passage regions 42 (42p, 42q, 42r). The passage region 42p, the passage region 42q, and the passage region 42r respectively correspond to sections of the refrigerant passage 40 formed in the plate member 31A, the plate member 31B, and the plate member 31C. The passage regions 42p, 42q, and 42r are arranged in the order mentioned, from the upstream side to the downstream side of the refrigerant flow in the refrigerant passage 40. The passage regions 42p and 42r face both ends of the cell stack 10 in the Y-axis direction in the vertical direction. The passage region 42q faces the middle part of the cell stack 10 in the Y-axis direction in the vertical direction.

[0056] The shape of the uneven portion 46 changes at the boundary between the passage region 42p and the passage region 42q, and also changes at the boundary between the passage region 42q and the passage region 42r. The shape of the uneven portion 46 does not change in each passage region 42 of the passage region 42p, the passage region 42q, and the passage region 42r.

[0057] The uneven portion 46 is provided such that, in the unit distance per flow direction of the refrigerant in the refrigerant passage 40, the surface area of the inner wall 47 in the passage region 42q facing the middle part of the cell stack 10 in the Y-axis direction is larger than the surface area of the inner wall 47 in each of the passage regions 42 of the passage regions 42p and 42r facing both ends of the cell stack 10 in the Y-axis direction. The number of ribs forming the uneven portion 46 in the passage region 42q is larger than the number of ribs forming the uneven portion 46 in each of the passage regions 42 of the passage regions 42p and 42r.

[0058] According to such a configuration, heat transfer from the battery cells 11 to the refrigerant flowing through the passage region 42q is promoted in the middle part of the cell stack 10 where heat dissipation is difficult, rather than at both ends of the cell stack 10 where heat dissipation is easy, so that the plurality of battery cells 11 can be cooled more evenly.

[0059] Further, the uneven portion 46 is provided such that, in a unit distance in the refrigerant flow direction in the refrigerant passage 40, the surface area of the inner wall 47 in the passage region 42r located on the downstream side of the refrigerant flow in the refrigerant passage 40 is larger than the surface area of the inner wall 47 in the passage region 42p located on the upstream side of the refrigerant flow in the refrigerant passage 40. The number of ribs forming the uneven portion 46 in the passage region 42r is larger than the number of ribs forming the uneven portion 46 in the passage region 42p.

[0060] With such a configuration, it is also possible to suppress variations in the cooling efficiency caused by the difference in refrigerant temperature between the upstream side and the downstream side of the refrigerant flow.

[0061] (Embodiment 3) FIG. 10 is a cross-sectional view showing a battery pack according to Embodiment 3 of the present invention. FIG. 10 corresponds to FIG. 4 in Embodiment 1.

[0062] The battery pack in the present embodiment basically has the same structure as the battery pack 100 in Embodiment 1. Hereinafter, the description of the overlapping structure will not be repeated.

[0063] Referring to FIG. 10, the battery pack in the present embodiment includes a plurality of battery cells 11, a plate member 31, and an electronic component unit 81. A cell stack 10 (10C, 10D, 10E) is configured by a plurality of battery cells 11 stacked in the Y-axis direction. The cell stack 10C, the cell stack 10D, and the cell stack 10E are arranged at intervals in the X-axis direction in the order listed. The cell stack 10E is disposed at a position adjacent to the case side portion 23 in the X-axis direction. The cell stack 10D is disposed between the cell stack 10C and the cell stack 10E in the X-axis direction.

[0064] The electronic component unit 81 includes a main relay, a shunt resistor, a cement resistor, a bus bar, a current sensor, etc., and a case for housing these electronic components. The electronic component unit 81 is housed in the case body 21. The cell stack 10C is arranged at a position adjacent to the electronic component unit 81 in the X-axis direction. The cell stack 10C is arranged between the cell stack 10D and the electronic component unit 81 in the X-axis direction.

[0065] A refrigerant passage 40 is formed in the plate member 31. The refrigerant passage 40 includes a plurality of passage regions 43 (43p, 43q, 43r). The passage region 43p, the passage region 43q, and the passage region 43r are arranged in the order mentioned, from the upstream side to the downstream side of the refrigerant flow in the refrigerant passage 40. Each passage region 43 of the passage region 43p, the passage region 43q, and the passage region 43r extends in the Y-axis direction. The passage region 43p, the passage region 43q, and the passage region 43r meander along the X-axis direction while alternately reversing and extending in the +Y-axis direction and the -Y-axis direction. The passage region 43p, the passage region 43q, and the passage region 43r face the cell stack 10C, the cell stack 10D, and the cell stack 10E in the vertical direction.

[0066] The shape of the uneven portion 46 changes at the boundary between the passage region 43p and the passage region 43q, and changes at the boundary between the passage region 43q and the passage region 43r. The shape of the uneven portion 46 does not change in each passage region 43 of the passage region 43p, the passage region 43q, and the passage region 43r.

[0067] The uneven portion 46 is provided such that, in the unit distance in the flow direction of the refrigerant in the refrigerant passage 40, the surface area of the inner wall 47 in the passage region 43p facing the cell stack 10C in the vertical direction is larger than the surface area of the inner wall 47 in the passage region 43r facing the cell stack 10E in the vertical direction. The number of ribs forming the uneven portion 46 in the passage region 43p is larger than the number of ribs forming the uneven portion 46 in the passage region 43r.

[0068] According to such a configuration, in the cell stack 10C that is more susceptible to the heat dissipation influence from the electronic component unit 81 than the cell stack 10E that is more likely to dissipate heat through the case side portion 23, by promoting the heat transfer from the battery cell 11 to the refrigerant flowing through the passage region 43p, a plurality of battery cells 11 can be cooled more evenly.

[0069] The uneven portion 46 is provided such that, per unit distance in the refrigerant flow direction in the refrigerant passage 40, the surface area of the inner wall 47 in the passage region 43q is smaller than the surface area of the inner wall 47 in the passage region 43p and larger than the surface area of the inner wall 47 in the passage region 43r. The number of ribs forming the uneven portion 46 in the passage region 43q is smaller than the number of ribs forming the uneven portion 46 in the passage region 43p and larger than the number of ribs forming the uneven portion 46 in the passage region 43r.

[0070] With such a configuration, in the cell stack 10D that is less susceptible to the heat dissipation influence from the electronic component unit 81 than the cell stack 10C but is less likely to dissipate heat through the case side portion 23 than the cell stack 10E, by adjusting the efficiency of the heat transfer from the battery cell 11 to the refrigerant flowing through the passage region 43q between the heat transfer from the battery cell 11 to the refrigerant flowing through the passage region 43p and the heat transfer from the battery cell 11 to the refrigerant flowing through the passage region 43r, a plurality of battery cells 11 can be cooled even more evenly.

[0071] It should be considered that all aspects of the embodiments disclosed this time are illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0072] 10, 10A, 10B, 10C, 10D, 10E cell stack, 11 battery cell, 12 exterior body, 13 first side surface, 14 second side surface, 15 top surface, 16 bottom surface, 17 gas discharge valve, 18 electrode terminal, 18N negative electrode terminal, 18P positive electrode terminal, 21 case body, 22 case bottom, 23 case side portion, 24 case top, 25 heat transfer member, 31, 31A, 31B, 31C plate member, 40 refrigerant passage, 41, 41p, 41q, 41r, 41s, 42, 42p, 42q, 42r, 43, 43p, 43q, 43r passage region, 46 uneven portion, 47 inner wall, 70 internal space, 81 electronic component unit, 100 battery pack.

Claims

1. A plurality of stacked battery cells; and a metal plate member thermally connected to the plurality of battery cells. The plate member includes an inner wall that defines a refrigerant passage through which refrigerant flows. The inner wall is provided with uneven portions that form a concave shape and / or a convex shape with respect to an opening formed by the refrigerant passage, and whose shape changes in the flow direction of the refrigerant in the refrigerant passage. The uneven portions are formed of the metal forming the plate member on the upper surface of the inner wall located between the plurality of battery cells and the opening formed by the refrigerant passage. The plate member includes a plurality of plate segments arranged in order from the upstream side to the downstream side of the refrigerant flow and connected to each other. The refrigerant passage includes a plurality of passage regions that extend parallel to each other and are connected so as to be arranged in order from the upstream side to the downstream side of the refrigerant flow, and are provided in the plurality of plate segments respectively. The shape of the uneven portions does not change in the flow direction of the refrigerant in the refrigerant passage in each of the passage regions, and is different from each other among the plurality of passage regions, a battery pack.

2. The refrigerant passage includes, as the plurality of passage regions, a first passage region and a second passage region located downstream of the first passage region in the refrigerant flow. The uneven portions are provided such that the surface area of the inner wall in the second passage region is larger than the surface area of the inner wall in the first passage region per unit distance in the flow direction of the refrigerant in the refrigerant passage. The battery pack according to claim 1.

3. A cell stack body composed of a plurality of the battery cells stacked in a predetermined direction is provided. The refrigerant passage includes, as the plurality of passage regions, a third passage region facing an end portion of the cell stack body in the predetermined direction and a fourth passage region facing an intermediate portion of the cell stack body in the predetermined direction. The concavo-convex portion is provided such that, per unit distance in the refrigerant flow direction in the refrigerant passage, the surface area of the inner wall in the fourth passage region is larger than the surface area of the inner wall in the third passage region. The battery pack according to claim 1 or 2.

4. A case body having side portions, An electronic component unit housed in the case body, A first cell stack formed of a plurality of the stacked battery cells and housed in the case body at a position adjacent to the side portion, A second cell stack formed of a plurality of the stacked battery cells and housed in the case body at a position adjacent to the electronic component unit, The refrigerant passage includes, as a plurality of the passage regions, a fifth passage region facing the first cell stack and a sixth passage region facing the second cell stack, The concavo-convex portion is provided such that, per unit distance in the refrigerant flow direction in the refrigerant passage, the surface area of the inner wall in the sixth passage region is larger than the surface area of the inner wall in the fifth passage region. The battery pack according to claim 1 or 2.

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