Heat sink

Abstract

To provide a heat sink that is less susceptible to the influence of outside air temperature and can appropriately control the temperature of a battery.SOLUTION: A heat sink 10, which cools or heats a battery, includes an upper plate and a lower plate 10a disposed opposite the upper plate. The heat sink 10 is composed of the upper plate and the lower plate 10a and has a first internal space 10b through which a cooling fluid flows. The lower plate 10a defines a plurality of individually separated branch flow passage portions 16, and the first internal spaces 10b of the plurality of branch flow passage portions 16 are all connected to the second internal space 10c of the main flow passage portion 12 via communication portions 16d and 16e. The plurality of branch flow passage portions 16 are made of resin.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a heat sink. [Background technology]

[0002] In recent years, automobiles equipped with motors as a driving source (such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs)) have become widespread. These automobiles are equipped with batteries to drive the motors.

[0003] Typically, the batteries installed in these vehicles are configured as a battery pack, with multiple cells housed in a container. Therefore, when the battery is used, heat is generated and trapped inside the container, causing it to become very hot. As high temperatures can accelerate battery degradation, the battery is cooled while in use to prevent the temperature from rising. One possible way to cool the battery is to use a heat sink.

[0004] Patent Document 1 discloses a battery module. The battery module is composed of a battery cell stack in which multiple battery cells are stacked, a module frame that houses the battery cell stack, and a heat sink located at the bottom of the module frame. The heat sink is composed of a plate-shaped upper plate and a lower plate with a recessed portion through which a coolant flows. Both the upper plate and the lower plate are made of an aluminum alloy. Aluminum alloys have high thermal conductivity and quickly transfer heat generated in the battery cells to cooling water (the coolant in Patent Document 1), suppressing temperature increases in the battery cells. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2023-534352 Summary of the Invention [Problem to be solved by the invention]

[0006] The aluminum alloy used as the heat sink for the battery module disclosed in Patent Document 1 has high thermal conductivity. Furthermore, due to its structure, the heat sink is often exposed to the outside air. Therefore, for example, when the outside air temperature is significantly higher than the temperature of the coolant, the outside air may raise the temperature of the coolant, potentially making it impossible to sufficiently cool the battery. Conversely, when the outside air temperature is significantly lower, the battery needs to be warmed by the coolant, but the outside air may lower the temperature of the coolant, potentially making it impossible to sufficiently warm the battery.

[0007] Therefore, there is a demand for a heat sink that is less susceptible to the influence of outside air temperature and can appropriately control the temperature of the battery. [Means for solving the problem]

[0008] One embodiment of a heat sink according to the present disclosure is a heat sink for cooling or heating a battery, comprising an upper plate and a lower plate arranged opposite the upper plate, and having a first internal space constituted by the upper plate and the lower plate through which a cooling fluid flows, the lower plate defining a plurality of individually divided branch flow path sections, the first internal spaces of the plurality of branch flow path sections all being connected to a second internal space of a main flow path section via a communication section, and the plurality of branch flow path sections being made of resin.

[0009] According to this embodiment, the multiple branch flow passages are made of resin, which has a lower thermal conductivity than metal. Therefore, the temperature of the cooling fluid flowing through the first internal space of the branch flow passages is less susceptible to the influence of the outside air temperature. Specifically, even if the outside air temperature is significantly higher than the temperature of the cooling fluid, the temperature of the cooling fluid is less likely to increase due to the outside air temperature. Furthermore, even if the outside air temperature is significantly lower than the temperature of the cooling fluid, the temperature of the cooling fluid is less likely to decrease due to the outside air temperature. Therefore, the heat sink of this embodiment can appropriately control the temperature of the battery regardless of the outside air temperature.

[0010] In addition, because the branch flow path portion of the heat sink of this embodiment is divided into multiple individual parts, the size of each branch flow path portion is reduced, which allows for improved molding precision and makes it easier to suppress warping, etc. Furthermore, because the branch flow path portion is divided into multiple individual parts, even if the battery case containing the battery is deformed due to a torsional load, etc., when the vehicle turns, the stress generated in the branch flow path portion can be reduced in response to the deformation. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an exploded perspective view of a battery module having a heat sink according to a first embodiment. FIG. [Figure 2] FIG. 2 is a bottom view of the battery module. [Figure 3] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. [Figure 4] FIG. 2 is a partially enlarged plan view of a lower plate that constitutes the heat sink. [Figure 5] FIG. 10 is a bottom view of a battery module having a heat sink according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a heat sink according to the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are merely examples for explaining the heat sink, and the heat sink is not limited to these embodiments. Therefore, the heat sink can be embodied in various forms without departing from the spirit of the present disclosure.

[0013] [First embodiment] The battery module A having the heat sink 10 according to the first embodiment is used, for example, in automobiles equipped with a motor as a driving source (hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), fuel cell electric vehicles (FCEVs), etc.).

[0014] As shown in FIG. 1 , the battery module A includes a plurality of (52 in this embodiment) parallelepiped-shaped cells 1a, a rectangular heat transfer sheet 3 that transfers heat generated by the cells 1a to a heat sink 10, a battery case 5 having a rectangular parallelepiped outer shape and housing the cells 1a and the heat transfer sheet 3 in a rectangular parallelepiped housing space 5d, and the heat sink 10 disposed in a lower case 5b of the battery case 5. The plurality of cells 1a are electrically connected to form the battery 1. For example, lithium ion batteries are used as the cells 1a. In this embodiment, the battery 1 is configured by connecting the plurality of cells 1a in series to form a cell block 1b, and four cell blocks 1b are connected in series or in parallel. This allows the battery 1 to generate a high voltage. The battery 1 has an overall rectangular parallelepiped shape. The battery case 5 is made of a metal such as iron or aluminum. The storage space 5d extending from the upper case 5a to the lower case 5b of the battery case 5 has a shape and volume that allows the battery 1 and the heat transfer sheet 3 to be stored therein with a small gap (see FIG. 3).

[0015] As shown in FIG. 3, the heat transfer sheet 3 is accommodated in the accommodation space 5d so as to abut against the rectangular bottom plate 5c (an example of an upper plate) of the lower case 5b of the battery case 5. The heat transfer sheet 3 is made of a material with high thermal conductivity, such as silicone. The battery 1 (cells 1a) is stacked on the heat transfer sheet 3 and accommodated in the accommodation space 5d. Hereinafter, the direction along the stacking direction of the heat transfer sheet 3 and the battery 1 will be referred to as the stacking direction Z. The direction in which the battery 1 is arranged when viewed from the heat transfer sheet 3 will also be referred to as the first stacking direction Z1, and the direction in which the heat transfer sheet 3 is arranged when viewed from the battery 1 will also be referred to as the second stacking direction Z2 (see also FIG. 1).

[0016] The heat sink 10 in this embodiment includes a bottom plate 5c of a lower case 5b and a resin lower plate 10a that faces the bottom plate 5c and is joined by adhesive, welding, or other methods (see FIG. 2). A plurality of grooves are formed in the lower plate 10a, and a first internal space 10b is formed by the grooves and the bottom plate 5c. Cooling water (an example of a cooling fluid) flows through the first internal space 10b. Note that FIG. 1 does not show the plurality of grooves and joints 12c and 16c (see FIG. 2) formed in the lower plate 10a of the heat sink 10.

[0017] The heat sink 10 exchanges heat with the coolant flowing through the first internal space 10b to cool or heat the battery 1 (cells 1a), thereby optimizing the temperature of the battery 1 and allowing the battery 1 to efficiently generate power. Specifically, when the outside air temperature around the battery module A is high, the coolant exchanges heat with the heat generated by the battery 1, thereby suppressing a rise in the temperature of the battery 1. When the outside air temperature is low, the coolant supplies heat to the battery 1 through heat exchange, thereby raising the temperature of the battery 1. The coolant in this embodiment is, for example, a coolant such as long-life coolant (LLC), or a liquid with high electrical insulation properties such as a fluorine-based inert liquid.

[0018] As shown in FIG. 1 , the lower plate 10a of the heat sink 10 of this embodiment is composed of multiple (eight in this embodiment) branch flow path sections 16 (an example of a lower plate). Each of the eight branch flow path sections 16 is a separate component that is individually divided. Here, "separately divided" means that each of the eight branch flow path sections 16 is a separate component that is not integrated with any of the other seven branch flow path sections 16. As will be described in detail later, each branch flow path section 16 has two flow paths, an inner flow path 16a and an outer flow path 16b. The inner flow path 16a and the outer flow path 16b are integrally formed to form a single branch flow path section 16. "Separately divided" does not mean that the two flow paths, the inner flow path 16a and the outer flow path 16b, are separated or can be separated within a single branch flow path section 16. Note that the branch flow path section 16 is made of resin.

[0019] The heat sink 10 also has a resin main flow path portion 12 connected to each of the eight branch flow path portions 16. The main flow path portion 12 is generally linear and, as shown in FIG. 4 , has two linear grooves that are parallel and adjacent to each other when viewed in the direction along the stacking direction Z (hereinafter also referred to as a plan view). Two second internal spaces 10c that are independent of each other are defined by the two grooves of the main flow path portion 12 and the bottom plate 5c. One of the two second internal spaces 10c serves as an inflow path 12a (an example of an inflow path) through which pre-heat-exchange cooling water flows from the outside into the battery module A, and the other of the two second internal spaces 10c serves as an outflow path 12b (an example of an outflow path) through which post-heat-exchange cooling water flows from the battery module A to the outside. That is, in the main flow path portion 12, the inflow path 12a and the outflow path 12b are arranged parallel to and adjacent to each other.

[0020] The main flow path portion 12 is arranged along one side near the outer edge of the rectangular bottom plate 5c. At this time, the main flow path portion 12 is aligned along the juxtaposition direction of the four cell blocks 1b housed in the housing space 5d of the battery case 5 (see FIG. 1). In other words, the main flow path portion 12 is aligned along one side of the battery 1.

[0021] As shown in FIG. 2, the eight branch flow path sections 16 are arranged parallel to each other and perpendicular to the main flow path section 12, i.e., perpendicular to the direction in which the four cell blocks 1b are arranged side by side. In other words, the branch flow path sections 16 are arranged along the longitudinal direction of the cell blocks 1b. Two branch flow path sections 16 face each other in one cell block 1b. Each branch flow path section 16 is generally linear and has two grooves that are parallel and adjacent to each other in a planar view (see FIGS. 3 and 4). Each of the two parallel grooves of the branch flow path section 16 has a U-shape in a planar view. Two independent first internal spaces 10b are formed by each of the two grooves of the branch flow path section 16 and the bottom plate 5c. Hereinafter, the inner side of the two U-shaped first internal spaces 10b in a planar view will be referred to as the inner flow path 16a, and the outer side of the two first internal spaces 10b will be referred to as the outer flow path 16b (see also FIG. 4).

[0022] As shown in FIG. 4 , one end of each of the inner flow path 16a and the outer flow path 16b communicates with the inlet channel 12a via an inlet hole 16d (an example of a communication portion) extending from the inner flow path 16a to the outer flow path 16b. The other end of each of the inner flow path 16a and the outer flow path 16b communicates with the outlet channel 12b via an outlet hole 16e (an example of a communication portion) extending from the inner flow path 16a to the outer flow path 16b. That is, the cooling water that flows into the inlet channel 12a from outside the battery module A flows through the inlet channel 12a and into one end of the inner flow path 16a and the outer flow path 16b of the branch flow path section 16 via the inlet hole 16d, and then flows through the inner flow path 16a and the outer flow path 16b. The cooling water then flows from the other end of the inner flow path 16a and the outer flow path 16b into the outlet channel 12b via the outlet hole 16e and flows out of the battery module A from the outlet channel 12b. That is, each of the branch flow path sections 16 branches off from the main flow path section 12, and the first internal space 10b of each of the branch flow path sections 16 is connected to the second internal space 10c of the main flow path section 12 via the inlet hole 16d and the outlet hole 16e. In other words, the inlet path 12a and the outlet path 12b of the main flow path section 12 are connected to each other via the inner flow path 16a and the outer flow path 16b of the branch flow path section 16. The flow direction of the cooling water flowing through the inlet path 12a is opposite to the flow direction of the cooling water flowing through the outlet path 12b.

[0023] Each of the eight branch flow path sections 16 has a joint 16c, and a first internal space 10b that becomes the inner flow path 16a and the outer flow path 16b is formed by joining the joint 16c to the bottom plate 5c by a method such as adhesive bonding or welding. In addition, the main flow path section 12 has a joint 12c, and after joining the eight branch flow path sections 16 to the bottom plate 5c, the joint 12c is joined to the branch flow path sections 16 and the bottom plate 5c by a method such as adhesive bonding or welding, thereby forming a second internal space 10c that becomes the inflow path 12a and the outflow path 12b.

[0024] Second Embodiment Next, a heat sink 10 according to a second embodiment will be described with reference to Fig. 5. In this embodiment, the configuration of the main flow path portion 12 is different from that of the heat sink 10 of the first embodiment. Other than that, the configuration is the same as that of the first embodiment. Therefore, in the description of this embodiment, parts having the same configuration as that of the first embodiment are given the same reference numerals, and detailed description of the same configuration will be omitted.

[0025] In the first embodiment, the main flow path section 12 had inflow channels 12a and outflow channels 12b formed by joining the joint section 12c to the branch flow path section 16 and the bottom plate 5c, but in the present embodiment, the main flow path section 12 is configured with piping. The piping that configures the main flow path section 12 is disposed outside the battery module A. In the present embodiment, the inflow channels 12a of the main flow path section 12 have eight sets (16 in total) of first outflow ports 12d, and the outflow channels 12b have eight sets (16 in total) of first inflow ports 12e. Each of the 16 first outflow ports 12d branches off from the inflow channel 12a, and each of the 16 first inflow ports 12e merges with the outflow channel 12b.

[0026] Each of the 16 first outlet ports 12d is connected to a second inlet port 16f (an example of a communicating portion) formed at one end of the inner flow path 16a and the outer flow path 16b of each of the eight branch flow path sections 16. Each of the 16 first inlet ports 12e is connected to a second outlet port 16g (an example of a communicating portion) formed at the other end of the inner flow path 16a and the outer flow path 16b of each of the eight branch flow path sections 16. A total of 16 second inlet ports 16f and 16 second outlet ports 16g are formed in the eight branch flow path sections 16.

[0027] With this configuration, the cooling water flowing through the inlet channel 12a of the main flow channel section 12, which is a pipe arranged outside the battery module A, flows through the inlet channel 12a and then flows into one end of the inner flow channel 16a and the outer flow channel 16b of the eight branch flow channel sections 16 via the 16 first outlet ports 12d and the 16 second inlet ports 16f. After flowing through the inner flow channel 16a and the outer flow channel 16b, the cooling water flows from the other end of the inner flow channel 16a and the outer flow channel 16b via the 16 second outlet ports 16g and the 16 first inlet ports 12e into the outlet channel 12b of the main flow channel section 12, which is a pipe, and flows through the outlet channel 12b.

[0028] Other Embodiments (1) In the first embodiment, the inflow channel 12a and the outflow channel 12b of the main channel portion 12 are arranged parallel to and adjacent to each other. However, this is not limiting. For example, the inflow channel 12a and the outflow channel 12b may be separated and arranged along two parallel sides near the outer edge of the rectangular bottom plate 5c. In this case, the inflow channel 12a and the outflow channel 12b of the main channel portion 12 are arranged along two parallel sides of the battery 1. In this embodiment, the inner channel 16a and the outer channel 16b formed by the branch channel portion 16 are not U-shaped in plan view, but are linear from the inflow channel 12a to the outflow channel 12b. Therefore, the branch channel portion 16 is composed of four parallel channels.

[0029] (2) In the first embodiment, the bottom plate 5c of the battery case 5 is used as the upper plate of the heat sink 10, but this is not limited to this. The heat sink 10 may be configured using a flat plate separate from the battery case 5 as the upper plate. In this case, the flat plate is preferably made of a metal with high thermal conductivity.

[0030] (3) In the above embodiments, the heat transfer sheet 3 is disposed on the lower case 5b of the battery case 5, but this is not limited to this. If heat is sufficiently transferred between the battery 1 and the coolant flowing through the heat sink 10, the battery module A does not need to have the heat transfer sheet 3.

[0031] (4) In the first embodiment, the flow direction of the cooling water flowing through the inflow passage 12a and the flow direction of the cooling water flowing through the outflow passage 12b are opposite to each other, but they may be the same direction.

[0032] [Summary of the above embodiment] Hereinafter, the heat sink (10) described in each of the above embodiments will be considered to have the following configuration.

[0033] <1> One aspect of the heat sink (10) is a heat sink (10) for cooling or heating a battery (1), comprising an upper plate (5c) and a lower plate (10a) arranged opposite the upper plate (5c), and comprising the upper plate (5c) and the lower plate (10a) and having a first internal space (10b) through which a cooling fluid flows, the lower plate (10a) forming a plurality of individually divided branch flow path portions (16), the first internal spaces (10b) of the plurality of branch flow path portions (16) all being connected to the second internal space (10c) of the main flow path portion (12) via communication portions (12d, 12e, 16f, 16g), and the plurality of branch flow path portions (16) being made of resin.

[0034] According to this configuration, the plurality of branch flow passages (16) are made of resin, which has a lower thermal conductivity than metal. Therefore, the temperature of the cooling fluid flowing through the first internal space (10b) of the branch flow passages (16) is less susceptible to the influence of the outside air temperature. Specifically, even if the outside air temperature is significantly higher than the temperature of the cooling fluid, the temperature of the cooling fluid is less likely to increase due to the outside air temperature. Furthermore, even if the outside air temperature is significantly lower than the temperature of the cooling fluid, the temperature of the cooling fluid is less likely to decrease due to the outside air temperature. Therefore, the heat sink (10) of this configuration can appropriately control the temperature of the battery (1) regardless of the outside air temperature.

[0035] In addition, because the branch flow path portions 16 of the heat sink 10 of this configuration are individually divided into multiple parts, the size of each branch flow path portion 16 is reduced, which allows for improved molding precision and facilitates suppression of warping, etc. Furthermore, because the branch flow path portions 16 are individually divided into multiple parts, even if the battery case 5 containing the battery 1 is deformed due to a torsional load, etc., when the vehicle turns, the stress generated in the branch flow path portions 16 can be reduced in response to the deformation.

[0036] <2> the above <1> In the heat sink (10) described above, the main flow path portion (12) is preferably made of resin.

[0037] In this configuration, because the main flow path portion (12) is made of resin, the temperature of the cooling fluid flowing through the second internal space (10c) of the main flow path portion (12) is less susceptible to the influence of the outside air temperature. Therefore, if the branch flow path portion (16) and the main flow path portion (12) constituting the heat sink (10) of this configuration are both made of resin, the temperature of the battery (1) can be more appropriately controlled regardless of the outside air temperature. Furthermore, if the main flow path portion (12) is made of resin, the main flow path portion (12) and the branch flow path portion (16) can be easily joined and integrated.

[0038] <3> the above <1> or <2> In the heat sink (10) described above, the main flow path portion (12) has an inflow flow path (12a) through which the cooling fluid flows from the outside into the second internal space (10c) and an outflow flow path (12b) through which the cooling fluid flows from the second internal space (10c) to the outside, and the inflow flow path (12a) and the outflow flow path (12b) are connected via a branch flow path portion (16), and it is preferable that the inflow flow path (12a) and the outflow flow path (12b) are arranged adjacent to each other along one side (1) of the battery that is rectangular in plan view.

[0039] According to this configuration, the pipes external to the heat sink (10) for supplying the cooling fluid circulating through the inlet flow passages (12a) of the heat sink (10) and the pipes external to the heat sink (10) for discharging the cooling fluid from the outlet flow passages (12b) can be arranged close to each other, thereby simplifying the piping configuration.

[0040] <4> the above <1> from <3> In the heat sink (10) described in any one of the above, it is preferable that the battery (1) is housed in a metal battery case (5), and the upper plate (5c) is a plate surface of the battery case (5).

[0041] According to this configuration, by using the upper plate (5c), which is a plate surface of the battery case (5), as the heat sink (10), the distance between the battery (1) and the cooling fluid flowing through the heat sink (10) is shortened, and heat can be efficiently transferred between the battery (1) and the cooling fluid flowing through the heat sink (10). [Industrial Applicability]

[0042] The present disclosure can be used for heat sinks. [Explanation of symbols]

[0043] 1: battery, 5: battery case, 5c: bottom plate (upper plate), 10: heat sink, 10a: lower plate, 10b: first internal space, 10c: second internal space, 12: main flow path portion (lower plate), 12a: inlet path (inlet flow path), 12b: outlet path (outlet flow path), 12d: outlet hole (communicating portion), 12e: inlet hole (communicating portion), 16: branch flow path portion (lower plate), 16f: second inlet port (communicating portion), 16g: second outlet port (communicating portion)

Claims

1. A heat sink for cooling or heating a battery, The top plate and A lower plate is provided opposite the upper plate, a first internal space formed by the upper plate and the lower plate and through which a cooling fluid flows; The lower plate forms a plurality of individually divided branch flow path portions, the first internal spaces of the plurality of branch flow path portions are all connected to the second internal space of the main flow path portion via communication portions, The plurality of branch flow passage portions are made of resin.

2. The heat sink according to claim 1 , wherein the main flow passage portion is made of resin.

3. the main flow path portion has an inflow flow path through which the cooling fluid flows from the outside into the second internal space and an outflow flow path through which the cooling fluid flows from the second internal space to the outside, the inflow channel and the outflow channel are connected via the branch channel portion, The heat sink according to claim 2 , wherein the inflow channel and the outflow channel are arranged adjacent to each other along one side of the battery, which is rectangular in plan view.

4. The battery is housed in a metal battery case, The heat sink according to claim 1 , wherein the upper plate is a plate surface of the battery case.

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