Battery module cooling device and method for producing battery module cooling device

Abstract

A battery module cooling device according to the present invention comprises: a heat transfer plate which is formed in a flat, band-like shape, which is provided between a plurality of battery cells that are disposed so as to face each other, and which extends in the arrangement direction of the plurality of battery cells; a coolant passage which is formed inside the heat transfer plate so as to extend in the arrangement direction of the plurality of battery cells, which includes an outbound path that extends from one end to the other end of the heat transfer plate and an inbound path that turns back at the other end and extends from the other end to the one end, and through which a coolant flows; an adhesive which bonds a side surface region of the heat transfer plate with the inbound path formed therein and respective side surfaces of the plurality of battery cells that are disposed so as to face each other; and a potting agent which has lower thermal conductivity than the adhesive and which fills the space between the side surface region of the heat transfer plate with the outbound path formed therein and the respective side surfaces of the plurality of battery cells that are disposed so as to face each other.

Description

A battery module cooling device and a method for manufacturing a battery module cooling device

[0001] The present invention relates to a battery module cooling device mounted on an electric vehicle, and a method for manufacturing the battery module cooling device.

[0002] In recent years, hybrid electric vehicles (HEV), which can effectively improve the fuel consumption rate (fuel efficiency) of vehicles by using both an engine and an electric motor, have been widely put into practical use. In addition, battery electric vehicles (BEV), which use only an electric motor as a power source and do not emit exhaust gas, have also been put into practical use.

[0003] Such hybrid vehicles and electric vehicles (electric vehicles) are equipped with a high-voltage battery (hereinafter sometimes simply referred to as "battery") for supplying power to an electric motor (or storing regenerated electric power). Here, generally, when a battery becomes high temperature, its charge-discharge performance decreases, and its service life also decreases (durability also deteriorates). Therefore, conventionally, for example, a water-cooled cooling device has been used which cools the battery by circulating cooling water, thereby suppressing temperature increase caused by heat generation of the battery and preventing degradation of performance and service life.

[0004] Incidentally, in a battery module using a water-cooled cooling device, as the cooling water flows through the flow path, heat exchange between the cooling water and the battery cells progresses, and the temperature of the cooling water rises. Therefore, there is a possibility that temperature variation occurs between battery cells (for example, between a battery cell located on the upstream side of the flow path and a battery cell located on the downstream side of the flow path). That is, among the plurality of battery cells, there is a possibility that some battery cells have relatively high temperature. As a result, as described above, there is a possibility that the charge-discharge performance of the high-temperature battery cell decreases, the service life thereof shortens, and the durability thereof deteriorates.

[0005] For example, Patent Document 1 discloses a technology (battery module) for suppressing temperature variations between multiple battery cells. More specifically, the battery module of Patent Document 1 comprises a plurality of battery cells arranged side by side, and a cooling mechanism arranged adjacent to each of the plurality of battery cells to cool the plurality of battery cells. This cooling mechanism has a cooling member provided with a flow path through which cooling water can flow, and a heat transfer member sandwiched between the plurality of battery cells and the cooling member, having a lower thermal conductivity than the cooling member. The thickness of the cooling member is formed to increase from upstream to downstream of the flow path, and the thickness of the heat transfer member is formed to decrease from upstream to downstream of the flow path.

[0006] According to the technology of Patent Document 1 (battery module), the thickness of the heat transfer member, which has a lower thermal conductivity than the cooling member, decreases from upstream to downstream of the flow path. As a result, the thermal resistance of the cooling mechanism to multiple battery cells decreases from upstream to downstream of the flow path. Therefore, heat exchange between the cooling water and the battery cells becomes easier on the downstream side compared to the upstream side. Thus, although the temperature of the cooling water rises from upstream to downstream of the flow path, the temperature rise of the battery cells on the downstream side can be suppressed. As a result, the temperature of each of the multiple battery cells can be kept approximately constant from upstream to downstream. In other words, the occurrence of temperature variations between multiple battery cells can be suppressed.

[0007] Japanese Patent Publication No. 2023-113296

[0008] As described above, the technology (battery module) described in Patent Document 1 can suppress (reduce) temperature variations between multiple battery cells. However, in the technology (battery module) described in Patent Document 1, the thickness of each of the cooling member and heat transfer member constituting the cooling mechanism must be continuously changed along the flow path, which can make the shape (structure) of the cooling mechanism complex and may pose problems from a manufacturability standpoint.

[0009] The present invention was made to solve the above-mentioned problems, and aims to provide a cooling device for a battery module that has a relatively simple (compared to conventional) and easy-to-manufacture structure (shape), and that can reduce temperature variations between multiple battery cells constituting the battery module, and a method for manufacturing the cooling device for the battery module.

[0010] A cooling device for a battery module according to one aspect of the present invention is characterized by comprising: a battery module in which a plurality of battery cells arranged in a row are positioned facing each other; a heat transfer plate formed in the shape of a flat plate and strip, disposed between the plurality of battery cells positioned facing each other and extending in the direction of the arrangement of the plurality of battery cells; a cooling liquid passage through which a cooling liquid flows, formed inside the heat transfer plate and extending in the direction of the arrangement of the plurality of battery cells, including a forward path extending from one end to the other end of the heat transfer plate, and a return path that folds back at the other end and extends from the other end to the one end; an adhesive that bonds the side region of the heat transfer plate in which the return path is formed inside and the side surfaces of each of the plurality of battery cells positioned facing each other; and a potting agent having a lower thermal conductivity than the adhesive, which is filled between the side region of the heat transfer plate in which the forward path is formed inside and the side surfaces of each of the plurality of battery cells positioned facing each other.

[0011] According to a cooling device for a battery module in one aspect of the present invention, a potting agent with lower thermal conductivity than adhesive is filled between the side region of the heat transfer plate, which has a forward path formed inside, and the side surfaces of each of the multiple battery cells arranged facing each other. This slows down the rise in the temperature of the coolant flowing through the forward path. Furthermore, since the side region of the heat transfer plate, which has a return path formed inside, is bonded to the side surfaces of each of the multiple battery cells arranged facing each other with an adhesive with higher thermal conductivity than the potting agent, the coolant flowing through the return path is more prone to temperature increases than the coolant flowing through the forward path. However, when a temperature difference occurs (becomes large) between the temperature of the coolant flowing through the return path and the temperature of the coolant flowing through the forward path, the return path side of the heat transfer plate and the coolant flowing through the return path are cooled by heat conduction from the heat transfer plate. As a result, the temperature of each battery cell (the entire battery module) is made uniform along the coolant path. On the other hand, according to one aspect of the present invention, since no special shapes or the like are required for each component (part) such as the heat transfer plate, the effect can be obtained with a relatively simple and easy-to-manufacture structure (compared to conventional methods).

[0012] According to the present invention, it is possible to reduce temperature variations between multiple battery cells constituting a battery module with a relatively simple (compared to conventional) and easily manufacturable structure (shape).

[0013] This figure shows the configuration of a cooling device for a battery module according to an embodiment. This is a cross-sectional view along line II-II in Figure 1. This figure shows the configuration of a cooling device for a battery module according to a modified example.

[0014] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals. In addition, in each drawing, the same elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0015] First, the configuration of the battery module cooling device 1 according to this embodiment will be described using Figures 1 and 2 together. Figure 1 is a diagram showing the configuration of the battery module cooling device 1. Figure 2 is a cross-sectional view taken along the line II-II in Figure 1.

[0016] The battery module 10 is installed in vehicles such as hybrid electric vehicles (HEVs) and electric electric vehicles (BEVs) and supplies power to the electric motor (or stores regenerated power).

[0017] The battery module 10 has multiple battery cells 100 arranged side by side (that is, multiple battery cells 100 arranged side by side and multiple battery cells 100 arranged side by side) facing each other. Furthermore, the multiple battery cells 100 are arranged side by side so that the axes of each battery cell 100 are parallel.

[0018] Each of the multiple battery cells 100 is formed, for example, in a substantially cylindrical or substantially rectangular prism shape. In this embodiment, a substantially cylindrical shape was used. For example, lithium-ion batteries are preferably used as the battery cells 100. However, instead of lithium-ion batteries, rechargeable secondary batteries such as nickel-metal hydride batteries can also be used.

[0019] The battery module cooling device 1 cools the battery module 10 (battery cell 100) by circulating cooling water (equivalent to a coolant), thereby suppressing the temperature rise caused by heat generation in the battery module 10 (battery cell 100) and preventing a decrease in performance and lifespan.

[0020] In particular, the cooling device 1 for the battery module has a relatively simple structure (shape) (compared to conventional devices) and has the function of reducing temperature variations among the multiple battery cells 100 that make up the battery module 10.

[0021] Therefore, the cooling device 1 for the battery module mainly consists of a heat transfer plate 20, a cooling water passage 30 (forward passage 301, return passage 302), an adhesive 40, and a potting agent 50.

[0022] The heat transfer (temperature control) plate 20 is formed, for example, in the shape of a flat plate and a strip. The heat transfer plate 20 is disposed between a plurality of battery cells 100 that are arranged facing each other (see Figure 2). The heat transfer plate 20 is also disposed so as to extend in the direction of arrangement (longitudinal direction) of the plurality of battery cells 100. The heat transfer plate 20 is made of a material with excellent thermal conductivity, that is, a thermal conductivity of several hundred [W / m·K], such as aluminum or copper.

[0023] The cooling water channel 30 (corresponding to the coolant channel) is formed inside the heat transfer plate 20 and extends in the direction of the arrangement of the multiple battery cells 100 (along the longitudinal direction). The cooling water channel 30 includes a forward path 301 extending from one end (inlet 303) to the other end of the heat transfer plate 20, and a return path 302 that makes a U-turn at the other end and extends from the other end to the one end (outlet 304). The cooling water channel 30 (forward path 301, return path 302) is formed with a substantially rectangular cross-sectional shape, as shown in Figure 2. However, the cooling water channel 30 (forward path 301, return path 302) may be formed with a circular cross-section. The size (cross-sectional area) of the cooling water channel 30 (forward path 301, return path 302) is set according to the cooling requirements of the battery module 10 (each battery cell 100), for example.

[0024] Cooling water flows through the cooling water channel 30. More specifically, the cooling water flows in from the inlet 303, flows along the forward path 301, makes a U-turn at the other end, flows along the return path 302, and is then discharged from the outlet 304. While flowing through the cooling water channel 30 (during circulation), the cooling water cools the battery module 10 (each battery cell 100) through heat exchange. The cooling water is circulated by, for example, an electric water pump (not shown).

[0025] In particular, in this embodiment, a pair (two) of cooling water channels 30 are formed inside the heat transfer plate 20, arranged in the shorter direction.

[0026] In the cooling water channel 30, the forward passage 301 is formed at one end (upper end) in the shorter direction of the heat transfer plate 20, and the return passage 302 is formed on the central side of the heat transfer plate 20.

[0027] In the other cooling water channel 30, the forward passage 301 is formed on the other end (lower end) side in the short direction of the heat transfer plate 20, and the return passage 302 is formed on the central side of the heat transfer plate 20. Therefore, the return passage 302 is sandwiched between the forward passage 301 of one cooling water channel 30 and the forward passage 301 of the other cooling water channel 30.

[0028] In this embodiment, the return path 302 of one cooling water channel 30 and the return path 302 of the other cooling water channel 30 are made common (integrated). However, a configuration in which the return paths 302 are not made common (integrated) (i.e., a configuration in which they are separated into two) is also possible.

[0029] The adhesive 40 used has a higher thermal conductivity than the potting agent 50 (for example, an epoxy-based material containing a thermally conductive filler, with a thermal conductivity of about 1 [W / m·K]). The adhesive 40 adheres the side region (the central part in the short direction) of the heat transfer plate 20, in which the return path 302 is formed, to the sides of each of the multiple battery cells 100 that are arranged facing each other (see Figure 2).

[0030] The potting agent (low thermal conductivity agent) 50 used has a lower thermal conductivity than the adhesive 40 (for example, a silicone-based resin with a thermal conductivity of about 0.1 [W / m·K]). The potting agent 50 is filled between the side regions (both short-sides) of the heat transfer plate 20, in which the forward path 301 is formed, and the sides of each of the multiple battery cells 100 that are arranged facing each other (see Figure 2).

[0031] Next, we will describe the manufacturing method of the battery module cooling device 1.

[0032] (1) In the first step, a plurality (a predetermined number) of battery cells 100 are arranged in a line. In this step, it is preferable to arrange (set) the substantially cylindrical battery cells 100 on an arrangement jig that has a cross section in which a predetermined number of semicircles are arranged in a line, and which holds a plurality (a predetermined number) of battery cells 100 in a line.

[0033] (2) In the second step, adhesive 40 is applied to the approximate center of each side surface of the multiple battery cells 100 arranged in a row (that is, the side surface area of ​​the heat transfer plate 20 in the following third step, where the side surface area in which the return path 302 is formed is bonded).

[0034] (3) In the third step, one side of the heat transfer plate 20 (the area in which the return path 302 is formed) is bonded to the multiple battery cells 100 with adhesive 40.

[0035] (4) In the fourth step, adhesive 40 is applied to the approximate center of the other surface of the heat transfer plate 20 (i.e., the region in which the return path 302 is formed).

[0036] (5) In the fifth step, multiple battery cells 100 are arranged side by side and bonded to the other side of the heat transfer plate 20 using adhesive 40.

[0037] (6) In the sixth step, after the adhesive 40 has hardened, potting agent 50 is filled between the sides of both ends of the heat transfer plate 20 in the short direction (i.e., the side regions of the heat transfer plate 20 in which both forward paths 301 are formed inside) and the sides of each of the multiple battery cells 100 that are arranged facing each other (i.e., the gaps at both ends in the short direction). Through the above steps, the cooling device 1 for the battery module is manufactured.

[0038] As described in detail above, according to this embodiment, a potting agent 50 with a lower thermal conductivity than the adhesive 40 is filled between the side region of the heat transfer plate 20 in which the forward path 301 is formed and the side surfaces of each of the multiple battery cells 100 arranged facing each other, so that the temperature rise of the cooling water flowing through the forward path 301 is slowed down. Also, since the side region of the heat transfer plate 20 in which the return path 302 is formed and the side surfaces of each of the multiple battery cells 100 arranged facing each other are bonded together with the adhesive 40, which has a higher thermal conductivity than the potting agent 50, the water temperature of the cooling water flowing through the return path 302 rises more easily than that of the cooling water flowing through the forward path 301. However, when a temperature difference occurs (becomes large) between the temperature of the cooling water flowing through the return path 302 and the temperature of the cooling water flowing through the forward path 301, the heat conduction of the heat transfer plate 20 cools the return path 302 side of the heat transfer plate 20 and the cooling water flowing through the return path 302. This ensures that the temperature of each battery cell 100 (the entire battery module 10) is uniform along the cooling water passage 30.

[0039] On the other hand, according to this embodiment, since no special shapes or the like are required for each component (part) such as the heat transfer plate 20, the effect can be obtained with a relatively simple (compared to conventional) structure that is easy to manufacture. In other words, it is possible to reduce temperature variations among the multiple battery cells 100 that make up the battery module 10 with a relatively simple (compared to conventional) structure (shape) that is easy to manufacture.

[0040] In particular, according to this embodiment, a pair of cooling water channels 30 are formed inside the heat transfer plate 20, arranged in the short direction. One cooling water channel 30 has a forward channel 301 formed on one end side in the short direction of the heat transfer plate 20, and a return channel 302 formed on the central side of the heat transfer plate 20. The other cooling water channel 30 has a forward channel 301 formed on the other end side in the short direction of the heat transfer plate 20, and a return channel 302 formed on the central side of the heat transfer plate 20. The side region of the heat transfer plate 20 in which the return channel 302 is formed is bonded to the side of each of the multiple battery cells 100 arranged opposite each other with adhesive 40, and potting agent 50 is filled between the side region of the heat transfer plate 20 in which the forward channel 301 is formed and the side of each of the multiple battery cells 100 arranged opposite each other. In other words, since the return path, where the coolant temperature tends to rise more easily than the forward path, is sandwiched between a pair of forward paths, the rise in the temperature of the coolant in the return path is effectively suppressed by heat conduction (heat exchange) within the heat transfer plate 20. Therefore, temperature variations among the multiple battery cells 100 (the entire battery module 10) can be further reduced (made more uniform).

[0041] According to this embodiment, the return passage 302 of one cooling water passage 30 and the return passage 302 of the other cooling water passage 30 are common (integrated). Therefore, the configuration (structure) of the cooling water passage 30 can be further simplified. In addition, the processing during manufacturing can be further simplified.

[0042] According to the method for manufacturing a battery module cooling device 1 according to the present embodiment, the method includes: a first step of arranging a plurality of battery cells 100 side by side; a second step of applying an adhesive 40 to a substantially central portion of a side surface of each of the plurality of battery cells 100 arranged side by side; a third step of adhering one surface of a heat transfer plate 20 to the plurality of battery cells 100 with the adhesive 40; a fourth step of applying the adhesive 40 to a substantially central portion of the other surface of the heat transfer plate 20; a fifth step of arranging and adhering the plurality of battery cells 100 side by side on the other surface of the heat transfer plate 20 with the adhesive 40; and a sixth step of filling a potting agent 50 between both end side surfaces in the width direction of the heat transfer plate 20 and side surfaces of each of the plurality of battery cells 100 arranged opposite to each other after the adhesive 40 is cured. Through the above steps, the aforementioned battery module cooling device 1 can be manufactured. Therefore, no special processing is required, and the device can be manufactured relatively more easily than conventional methods. Thus, it is possible to improve manufacturability.

[0043] Hitherto, embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above embodiment, a configuration is adopted in which a pair (two) of cooling water channels (coolant channels) 30 are formed inside the heat transfer plate 20. However, as shown in FIG. 3, the number of cooling water channels 30B formed inside a heat transfer plate 20B may be one. Here, FIG. 3 is a diagram showing the configuration of a battery module cooling device 1B according to a modified example. Other configurations are the same or similar to those of the above-described battery module cooling device 1, so detailed description thereof is omitted here.

[0044] Furthermore, in the above embodiment, the return path 302 of one cooling water channel 30 and the return path 302 of the other cooling water channel 30 are shared (integrated), but a configuration in which the return paths 302 are not shared (that is, a configuration separated into two paths) may also be adopted.

[0045] Furthermore, the dimensions, materials (raw materials), other specific numerical values and the like shown in the above embodiments are examples for facilitating understanding of the present invention, and do not limit the present invention unless otherwise specifically stated.

[0046] 1, 1B Battery module cooling device 10, 10B Battery module 100 Battery cell 20, 20B Heat transfer plate 30, 30B Coolant passage 301, 301B Forward passage 302, 302B Return passage 303 Inlet 304 Outlet 40, 40B Adhesive 50, 50B Potting agent

Claims

1. A cooling device for a battery module comprising: a battery module in which a plurality of battery cells arranged in a row are positioned facing each other; a heat transfer plate formed in the shape of a flat plate and strip, disposed between the plurality of battery cells positioned facing each other and extending in the direction of the arrangement of the plurality of battery cells; a cooling liquid passage through which a cooling liquid flows, formed inside the heat transfer plate and extending in the direction of the arrangement of the plurality of battery cells, including a forward path extending from one end to the other end of the heat transfer plate, and a return path that folds back at the other end and extends from the other end to the one end; an adhesive that bonds the side region of the heat transfer plate in which the return path is formed inside and the side surfaces of each of the plurality of battery cells positioned facing each other; and a potting agent having a lower thermal conductivity than the adhesive, which is filled between the side region of the heat transfer plate in which the forward path is formed inside and the side surfaces of each of the plurality of battery cells positioned facing each other.

2. The cooling device for a battery module according to claim 1, wherein a pair of cooling fluid passages are formed inside the heat transfer plate, arranged in the short direction, and one cooling fluid passage has a forward passage formed on one end side in the short direction of the heat transfer plate and a return passage formed on the central side of the heat transfer plate, and the other cooling fluid passage has a forward passage formed on the other end side in the short direction of the heat transfer plate and a return passage formed on the central side of the heat transfer plate, the adhesive bonds the side regions of the heat transfer plate in which both return passages are formed inside and the side regions of each of the plurality of battery cells arranged opposite to each other, and the potting agent is filled between the side regions of the heat transfer plate in which both forward passages are formed inside and the side regions of each of the plurality of battery cells arranged opposite to each other.

3. The cooling device for a battery module according to claim 2, characterized in that the return path of one of the cooling fluid passages and the return path of the other cooling fluid passage are shared.

4. The cooling device for a battery module according to claim 3, characterized in that each of the plurality of battery cells is formed in a substantially cylindrical or substantially rectangular prism shape, and the plurality of battery cells are arranged in a line such that the axes of each battery cell are parallel.

5. A method for manufacturing a cooling device for a battery module according to claim 2, comprising: a first step of arranging the plurality of battery cells side by side; a second step of applying an adhesive to the approximate center of each side surface of the plurality of battery cells arranged side by side; a third step of bonding one surface of the heat transfer plate to the plurality of battery cells with the adhesive; a fourth step of applying an adhesive to the approximate center of the other surface of the heat transfer plate; a fifth step of bonding the plurality of battery cells to the other surface of the heat transfer plate in a side by side with the adhesive; and a sixth step of filling the space between the side surfaces of both ends of the heat transfer plate and the side surfaces of the plurality of battery cells arranged opposite each other after the adhesive has hardened.

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