heat exchanger

Abstract

In a heat exchanger that exchanges heat with multiple battery cells, the device follows the expansion or contraction of the battery cells and suppresses a decrease in heat exchange efficiency. [Solution] A heat exchanger configured to exchange heat with multiple battery cells, each formed in a cylindrical shape. The heat exchanger comprises an outer shell member and an elastic member. The outer shell member forms a flow path for a heat exchange medium inside. The elastic member is disposed inside the outer shell member. The outer shell member has at least one heat exchange surface, which is arranged along the sides of the multiple battery cells and configured to exchange heat with the multiple battery cells. The elastic member presses the heat exchange surface from the inside of the outer shell member toward the outside of the outer shell member.

Description

Technical Field

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[0001] The present disclosure relates to a heat exchanger that performs heat exchange with a plurality of battery cells.

Background Art

[0002] Conventionally, in a battery system mounted on an electric vehicle, a technique for performing heat exchange between a battery cell and a heat exchange medium is known for discharging heat generated from the battery cell. For example, in Patent Document 1 below, a technique has been proposed in which a corrugated heat exchanger abuts on a plurality of battery cells and performs heat exchange.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as a result of the inventors' detailed examination, it has been found that the tube of Patent Document 1 has a problem that the heat exchange surface cannot follow the expansion or contraction of the battery cell, resulting in a decrease in heat exchange efficiency. Since the tube of Patent Document 1 is provided with a wall that divides the flow path inside the flow path, it cannot deform following the deformation of the battery cell, and a gap may occur between the tube and the battery cell.

[0005] One aspect of the present disclosure is to follow the expansion or contraction of a battery cell and suppress a decrease in heat exchange efficiency in a heat exchanger that performs heat exchange with a plurality of battery cells.

Means for Solving the Problems

[0006] <0One aspect of the present disclosure is a heat exchanger configured to exchange heat with a plurality of battery cells, each formed in a cylindrical shape. The heat exchanger comprises an outer shell member and an elastic member. The outer shell member forms a flow path for a heat exchange medium inside. The elastic member is disposed inside the outer shell member. The outer shell member has at least one heat exchange surface, which is arranged along the sides of the plurality of battery cells and configured to exchange heat with the plurality of battery cells. The elastic member presses the heat exchange surface from the inside of the outer shell member toward the outside of the outer shell member.

[0007] With this configuration, the elastic member presses the outer shell member from the inside in the direction of the heat exchange surface, thereby pressing the heat exchange surface in a direction that brings it into contact with the battery cell. As a result, the heat exchange surface follows the expansion and contraction of the battery cell. This allows the heat exchanger to maintain a state where the heat exchange surface and the battery cell are in contact, thereby suppressing a decrease in heat exchange efficiency.

[0008] In one aspect of this disclosure, the plurality of battery cells may be cylindrical. The outer shell member may be curved along the sides of the plurality of battery cells. With this configuration, the contact area between the sides of multiple battery cells and the heat exchange surface is increased. Therefore, the heat exchanger can perform heat exchange efficiently.

[0009] In one aspect of this disclosure, the elastic member may be a leaf spring. With this configuration, elastic members with shapes suitable for the shape of the outer shell member can be easily formed. Therefore, the manufacturing cost of the heat exchanger can be reduced.

[0010] In one aspect of this disclosure, the elastic member may be made of metal. This configuration allows for the use of highly heat-resistant elastic materials. Therefore, the heat resistance of the heat exchanger can be improved, thereby suppressing the deterioration of the heat exchanger caused by the heat generated in the battery cells.

[0011] In one aspect of this disclosure, the outer shell member may have a first and second surface facing each other and be positioned between a plurality of battery cells located adjacent to the first and second surfaces. The first and second surfaces may function as heat exchange surfaces. The elastic member may be positioned near a straight line connecting the two battery cells sandwiching the outer shell member by the shortest distance.

[0012] With this configuration, the elastic member presses the heat exchange surface from the inside of the outer shell member toward the outside of the outer shell member in the region where the displacement of the outer shell member due to the expansion of the battery cell is greatest. Therefore, the flow path of the heat exchange medium is secured, and the function of the heat exchanger can be guaranteed. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1A is a top view of the battery system. Figure 1B is a cross-sectional view of the IB-IB section in Figure 1A. [Figure 2] Figure 2A is a perspective view of the heat exchanger. Figure 2B is a perspective view of a part of the elastic member. [Figure 3] Figure 3A is a top view of the end of the heat exchanger. Figure 3B is a cross-sectional view taken along the line IIIB-IIIB in Figure 3A. [Figure 4] This is a top view showing the heat exchanger and the battery cell in contact. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described below with reference to the drawings. [1. First Embodiment] [1-1. Structure] The battery system 100 shown in Figures 1A and 1B is installed in a vehicle, particularly an electric vehicle. An electric vehicle is an automobile that runs using electrical energy stored in a battery, such as multiple battery cells 2, as all or part of its power. Electric vehicles include electric vehicles, plug-in hybrid vehicles, hybrid vehicles, fuel cell vehicles, etc. The battery system 100 is installed, for example, under the body of the vehicle. The battery system 100 comprises a battery pack 1, multiple battery cells 2, and a heat exchange system 3.

[0015] The battery pack 1 is a component that forms a housing space 11 for housing a plurality of battery cells 2. The battery pack 1 may have any shape as long as it can house a plurality of battery cells 2. In this embodiment, the outer shape of the battery pack 1 is a rectangular parallelepiped. A communication port 12 may be formed on the outer surface of the battery pack 1. The communication port 12 is an opening that connects the inside and outside of the battery pack 1. The communication port 12 may be provided with an introduction section 31 and an discharge section 32 of the heat exchange system 3, which will be described later. In other words, the communication port 12 functions to allow a heat exchange medium to flow into or out of the battery pack 1. The communication port 12 may be formed, for example, on the side of the battery pack 1 in the vehicle's longitudinal direction or vehicle's width direction, or on the top surface of the battery pack 1.

[0016] The battery cell 2 supplies power to a motor that drives a vehicle, for example, when the battery system 100 is mounted on the vehicle. A specific example of the battery cell 2 is a lithium-ion battery. The shape of the battery cell 2 is cylindrical, rectangular prism, or other cylindrical shape. In this embodiment, the battery cell 2 is cylindrical. The battery cell 2 can expand or contract due to the heat generated during charging and discharging.

[0017] Multiple battery cells 2 are arranged in the housing space 11. Multiple battery cells 2 may be arranged at a constant distance from other adjacent multiple battery cells 2. In this embodiment, multiple battery cells 2 are arranged in a staggered pattern. That is, in two parallel rows of multiple battery cells 2, the battery cells 2 are arranged alternately.

[0018] Furthermore, a part of the outer periphery of the battery cell 2 in the other row enters the gap between the outer peripheries of the adjacent battery cells 2 in one row. In addition, as shown by the virtual line A in FIG. 3A, the center-to-center distance, which is the distance between the center of a certain battery cell 2 and the center of the battery cell 2 in the adjacent row, is set to be the sum of the radius of a certain battery cell 2, the radius of the battery cell 2 in the adjacent row, and the thickness of the heat exchanger 33. The plurality of battery cells 2 are preferably filled as densely as possible in the accommodation space 11.

[0019] The heat exchange system 3 is a system that performs heat exchange with the plurality of battery cells 2. The heat exchange system 3 cools or heats the plurality of battery cells 2 by performing heat exchange with the plurality of battery cells 2. The heat exchange system 3 includes an introduction part 31, a discharge part 32, and a heat exchanger 33.

[0020] The introduction part 31 is a member that is connected to the heat exchanger 33 and introduces the heat exchange medium into the interior of the heat exchanger 33. That is, the heat exchange medium is introduced into the interior of the heat exchanger 33 by a pump (not shown) through the introduction part 31. The introduction part 31 of the present embodiment is arranged at the first end part (the left end part in FIG. 1) in the battery pack 1. The introduction part 31 may be connected to the outside of the battery pack 1 through the communication port 12.

[0021] The discharge part 32 is a member that is connected to the heat exchanger 33 and discharges the heat exchange medium that has performed heat exchange with the plurality of battery cells 2 to the outside of the heat exchanger 33. The discharge part 32 of the present embodiment is arranged at the second end part in the battery pack 1. The second end part is the end part (the right end part in FIG. 1) that faces the first end part in the battery pack 1. The discharge part 32 may be connected to the outside of the battery pack 1 through the communication port 12.

[0022] The heat exchanger 33 shown in Figure 2A is the part that performs heat exchange between the heat exchange medium and the multiple battery cells 2. The heat exchanger 33 is connected to the inlet 31 and the outlet 32. The heat exchanger 33 is located within the housing space 11. The heat exchanger 33 comprises an outer shell member 35 and an elastic member 36. The heat exchanger 33 may further include a medium inlet / outlet 37. The medium inlet / outlet 37 is connected to the inlet 31 and the outlet 32 ​​and functions as an inlet or outlet for the heat exchange medium to the heat exchanger 33.

[0023] The outer shell member 35 is a member that forms a flow path for the heat exchange medium inside. As shown in Figures 3A and 4, the heat exchanger 33 is positioned so that the outer shell member 35 is along the sides of the multiple battery cells 2. The outer shell member 35 may have a curved shape to follow the sides of the battery cells 2. For example, the outer shell member 35 may be curved in an arc shape to follow the sides of the multiple cylindrical battery cells 2. If a rectangular prism-shaped battery cell 2 is used, the outer shell member 35 may be bent at approximately a right angle to follow the sides of the rectangular prism-shaped battery cell 2.

[0024] As shown in Figures 3A and 3B, the outer shell member 35 is formed by joining a plate material 38a having a first surface and a plate material 38b having a second surface, such that the first and second surfaces face each other. The first and second surfaces refer to the planes of the plate material 38a and the plate material 38b, respectively. Here, it is preferable that the first and second surfaces are as smooth as possible.

[0025] The material of the plate material 38a and plate material 38b is not particularly limited, and can be, for example, stainless steel, aluminum, and resin. The thickness of the plate material 38a and plate material 38b is not particularly limited as long as heat exchange takes place between the heat exchange medium and the battery cell 2, but is preferably 0.2 mm or less.

[0026] The method of joining the two plate materials 38a and 38b is not particularly limited, as long as the heat exchange medium does not leak. For example, welding, brazing, or adhesive can be used as joining methods. The outer shell member 35 may be formed by processing a single pipe-shaped cylinder.

[0027] The outer shell member 35 has at least one heat exchange surface 39. The heat exchange surface 39 is a surface configured to exchange heat between the heat exchange medium and the plurality of battery cells 2. In other words, the heat exchange medium exchanges heat with the battery cells 2 via the heat exchange surface 39. At least one of the first surface and the second surface may function as the heat exchange surface 39. In this embodiment, both the first surface and the second surface function as the heat exchange surface 39.

[0028] The elastic member 36 is a member that presses the heat exchange surface 39 from the inside of the outer shell member 35 toward the outside of the outer shell member 35. As shown in Figure 3B, the elastic member 36 is positioned inside the outer shell member 35, that is, within the flow path of the heat exchange medium. The elastic member 36 may be made of, for example, a coil spring, rubber, silicone, etc. The material of the elastic member 36 is not particularly limited, but it is preferably made of metal.

[0029] The elastic member 36 in this embodiment is a leaf spring as shown in Figure 2B. The leaf spring is formed so that a plurality of spring portions 36b are provided on a single base portion 36a. The leaf spring is arranged inside the outer shell member 35 along the inner wall, so as shown in Figure 3B, it rises up to close the flow path of the heat exchange medium with a surface. Since the spring portions 36b of the elastic member 36 are formed with spacing between them, at least a part of the flow path of the heat exchange medium is open and does not block the flow of the heat exchange medium. In this case, the spring portions 36b may rise from the first surface side toward the second surface, or from the second surface side toward the first surface.

[0030] The elastic member 36 may be positioned near a virtual straight line connecting two adjacent battery cells 2 separated by the first and second surfaces at the shortest distance. Here, the virtual straight line connecting the two battery cells 2 at the shortest distance refers, for example, to the straight line connecting the central axes of the cylindrical battery cells 2. If the battery cells 2 are rectangular prisms or otherwise, and the first and second surfaces are in contact with a non-cylindrical battery cell 2 on a plane, it refers to a straight line intersecting the plane of contact. Furthermore, the vicinity of the virtual straight line refers to the range in which the displacement of the flow path width is relatively large when expansion occurs in the two adjacent battery cells 2 separated by the first and second surfaces, or the range in which the heat exchange surface 39 may cease to be in contact with the battery cells 2 due to the contraction of the two battery cells 2.

[0031] For example, if a leaf spring is used as the elastic member 36, a pair of leaf springs rising in the flow path may be arranged so as to straddle a virtual straight line, as shown in Figure 4. If a coil spring is used as the elastic member 36, the coil spring may be arranged on the virtual straight line.

[0032] [1-2. Effects] The first embodiment described in detail above provides the following effects. (1a) The outer shell member 35 forms a flow path for the heat exchange medium inside and has at least one heat exchange surface 39. The elastic member 36 is positioned in the flow path for the heat exchange medium and presses the outer shell member 35 from the inside toward the outside of the outer shell member 35. The heat exchanger 33 is positioned so that the heat exchange surface 39 of the outer shell member 35 is along the sides of the multiple battery cells 2.

[0033] With this configuration, the heat exchange surface 39 comes into contact with the side surface of the battery cell 2 as the elastic member 36 presses against the outer shell member 35 from the inside. Therefore, the heat exchanger 33 can perform heat exchange between the heat exchange medium flowing inside and the battery cell 2.

[0034] In addition, even when the battery cell 2 expands and presses the outer shell member 35 inward, or when the battery cell 2 contracts and a gap is likely to form between the battery cell 2 and the outer shell member 35, the elastic member 36 presses the outer shell member 35 from the inside. As a result, the heat exchange surface 39 follows the expansion or contraction of the battery cell 2. Therefore, the heat exchanger 33 is less likely to form a gap between the heat exchange surface 39 and the battery cell 2, maintaining a state of contact between them and suppressing a decrease in heat exchange efficiency.

[0035] (1b) In the above embodiment, the elastic member 36 is a leaf spring. With this configuration, the elastic member 36 can be easily formed in a shape suitable for the shape of the outer shell member 35. Therefore, the manufacturing cost of the heat exchanger 33 can be reduced.

[0036] (1c) In the above embodiment, the elastic member 36 is made of metal. With this configuration, an elastic member 36 with high heat resistance can be used. Therefore, the heat resistance of the heat exchanger 33 can be improved, and the deterioration of the heat exchanger 33 due to the heat generated in the battery cell 2 can be suppressed.

[0037] (1d) In the above embodiment, the outer shell member 35 has a first surface and a second surface facing each other, and is arranged to be sandwiched between a plurality of battery cells 2 positioned adjacent to the first surface and the second surface. The first surface and the second surface function as a heat exchange surface 39. The elastic member 36 is arranged near the straight line connecting the two battery cells 2 sandwiching the outer shell member 35 by the shortest distance.

[0038] With this configuration, the elastic member 36 presses the heat exchange surface 39 from the inside of the outer shell member 35 toward the outside of the outer shell member 35 in the region where the displacement of the outer shell member 35 due to the expansion of the battery cell 2 is greatest. Therefore, the flow path of the heat exchange medium is secured and the function of the heat exchanger 33 can be guaranteed.

[0039] In addition, near the straight line connecting two adjacent battery cells 2 at the shortest distance, the heat exchange surface 39 no longer comes into contact with the battery cells 2 due to the contraction of the two battery cells 2. According to the above configuration, the elastic member 36 presses the outer shell member 35 from the inside of the outer shell member 35 not only along the straight line connecting two adjacent battery cells 2 at the shortest distance, but also in the range where the heat exchange surface 39 no longer comes into contact with the battery cells 2. As a result, the heat exchange surface 39 follows along the side surface of the contracted battery cell 2. In this way, the heat exchanger 33 can maintain a state in which the heat exchange surface 39 and the battery cells 2 are in contact, thereby suppressing a decrease in heat exchange efficiency.

[0040] [2. Other Embodiments] Although embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be implemented in various modified forms.

[0041] (2a) In the above embodiment, the heat exchange system 3 introduces the heat exchange medium from outside the battery pack 1 and discharges the heat exchange medium outside the battery pack 1 after heat exchange has been performed, but it is not limited to this. For example, the heat exchange system 3 may not discharge the heat exchange medium outside the battery pack 1 after heat exchange, but instead reintroduce it into the heat exchanger 33. In this case, the battery pack 1 may be equipped with a cooler for the heat exchange medium.

[0042] (2b) In the above embodiment, the heat exchanger 33 is arranged to extend in the longitudinal direction of the vehicle, but is not limited thereto. The heat exchanger 33 may be arranged to extend in the width direction of the vehicle, or to fold back in the longitudinal direction of the vehicle.

[0043] (2c) In the above embodiment, the heat exchanger 33 is arranged to be sandwiched between a plurality of battery cells 2 arranged in a staggered pattern, but is not limited to this. The heat exchanger 33 may be arranged to sandwich the battery cells 2, for example.

[0044] [Technical concepts disclosed in this specification] [Item 1] A heat exchanger configured to exchange heat with multiple battery cells, each formed in a cylindrical shape, An outer shell member that forms a flow path for a heat exchange medium inside, An elastic member disposed inside the outer shell member, Equipped with, The outer shell member is arranged along the sides of the plurality of battery cells and has at least one heat exchange surface configured to perform heat exchange with the plurality of battery cells, The elastic member presses the heat exchange surface from the inside of the outer shell member toward the outside of the outer shell member. heat exchanger. [Item 2] The heat exchanger described in item 1, The aforementioned plurality of battery cells are cylindrical, The outer shell member has a curved shape that follows the sides of the plurality of battery cells. heat exchanger. [Item 3] A heat exchanger as described in item 1 or item 2, The elastic member is a leaf spring. heat exchanger. [Item 4] A heat exchanger described in any one of items 1 to 3, The elastic member is made of metal. heat exchanger. [Item 5] A heat exchanger described in any one of items 1 to 4, The outer shell member has a first surface and a second surface facing each other, and is arranged to be sandwiched between the plurality of battery cells positioned adjacent to the first surface and the second surface. The first and second surfaces function as heat exchange surfaces, The elastic member is positioned near the straight line connecting the two battery cells sandwiching the outer shell member by the shortest distance. heat exchanger. [Explanation of Symbols]

[0045] 1...Battery pack, 2...Battery cell, 3...Heat exchange system, 11...Housing space, 12...Communication port, 31...Inlet, 32...Outlet, 33...Heat exchanger, 35...Outer shell member, 36...Elastic member, 36a...Base, 36b...Spring part, 37...Media inlet / outlet, 38a, 38b...Plate material, 39...Heat exchange surface, 100...Battery system.

Claims

1. A heat exchanger configured to exchange heat with multiple battery cells, each formed in a cylindrical shape, An outer shell member that forms a flow path for a heat exchange medium inside, An elastic member disposed inside the outer shell member, Equipped with, The outer shell member is arranged along the sides of the plurality of battery cells and has at least one heat exchange surface configured to perform heat exchange with the plurality of battery cells, The elastic member presses the heat exchange surface from the inside of the outer shell member toward the outside of the outer shell member. heat exchanger.

2. A heat exchanger according to claim 1, The aforementioned plurality of battery cells are cylindrical, The outer shell member has a curved shape that follows the sides of the plurality of battery cells. heat exchanger.

3. A heat exchanger according to claim 1 or claim 2, The elastic member is a leaf spring. heat exchanger.

4. A heat exchanger according to claim 1 or claim 2, The elastic member is made of metal. heat exchanger.

5. A heat exchanger according to claim 1 or claim 2, The outer shell member has a first surface and a second surface facing each other, and is arranged to be sandwiched between the plurality of battery cells positioned adjacent to the first surface and the second surface. The first and second surfaces function as heat exchange surfaces, The elastic member is positioned near the straight line connecting the two battery cells sandwiching the outer shell member by the shortest distance. heat exchanger.

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