Cooler

Abstract

To provide a cooler capable of appropriately cooling a battery module.SOLUTION: A cooler 1 for cooling a battery module 2 having a plurality of cells 3 arranged along a first direction includes a cooling plate 20 provided between the sides of two adjacent cells 3 along the first direction, the cooling plate 20 includes a flow path 21 therein through which an insulating cooling liquid flows, and a rupture structure D for leaking the cooling liquid from the flow path in response to expansion of the cells 3.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cooler for cooling a battery module having a plurality of cells. [Background technology]

[0002] In recent years, automobiles equipped with a motor 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 (hereinafter collectively referred to as "electric vehicles") are equipped with a battery (hereinafter simply referred to as the battery) for driving the motor.

[0003] Generally, batteries installed in electric vehicles are configured by housing a battery module in which multiple battery cells are arranged in parallel in a container. Therefore, when the battery is in use, heat is generated by the cells and trapped inside the container, causing the battery to become hot. Since the battery deteriorates when it becomes hot, technology for cooling the battery has been studied (for example, Patent Document 1).

[0004] Patent Document 1 describes a battery pack having a plurality of cells. In this battery pack, connecting passages are provided between the cells, and a cooling fluid is circulated through the connecting passages to cool the cells from the sides.

[0005] Here, if any abnormality occurs in a cell constituting a battery, the temperature may rise and lead to thermal runaway. The battery pack described in Patent Document 1 is configured with multiple cells as described above. In the battery pack described in Patent Document 1, the cells are cooled from the sides, improving the cooling capacity, but since heat is easily transferred between cells, if one of the multiple cells leads to thermal runaway, the heat is transferred to an adjacent cell, and the temperature of the adjacent cell also rises, which may lead to a chain reaction of thermal runaway. A technology for preventing such a chain reaction of thermal runaway is described in Patent Document 2.

[0006] Patent Document 2 describes a battery cooling device. This battery cooling device includes a battery cooling circuit that circulates a liquid-phase refrigerant between a cooler and a condenser. The cooler is provided in contact with the side surfaces of two adjacent battery cells, and cools the battery cells by absorbing heat generated by the battery cells and evaporating the liquid-phase refrigerant. A thin-walled portion is provided on the passage wall of the electric heating portion of the cooler, and if any abnormality occurs in the battery cell, the refrigerant pressure increases as the temperature of the battery cell increases. If this refrigerant pressure exceeds the pressure resistance strength of the thin-walled portion, the electric heating portion bursts, releasing a large amount of refrigerant gas around the battery cell, thereby cooling the battery cell. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent No. 111384465 [Patent Document 2] JP 2023-7778 A Summary of the Invention [Problem to be solved by the invention]

[0008] The battery cooling device described in Patent Document 2 cools the battery cells by emitting high-pressure refrigerant gas, but because the refrigerant gas is released into the atmosphere, depending on the surrounding temperature, the refrigerant gas may be heated by the atmosphere, reducing the cooling capacity.

[0009] Therefore, there is a need for a cooler that can appropriately cool the battery module. [Means for solving the problem]

[0010] A characteristic configuration of the cooler of the present invention is that it is a cooler for cooling a battery module having a plurality of cells arranged along a first direction, and includes a cooling plate provided between side surfaces of two adjacent cells along the first direction, the cooling plate having a flow path therein through which an insulating cooling liquid flows, and a rupture structure is provided to cause the cooling liquid to leak from the flow path in response to expansion of the cells.

[0011] With this characteristic configuration, the cells can be cooled from the sides by the cooling liquid flowing through the flow paths in the cooling plate. In addition, since the cooling liquid is configured to leak from the flow paths when the cells expand, the cooling liquid is sprayed onto the expanded cell, and the temperature rise of the cell can be suppressed in a focused manner. As a result, only the expanded cell can be efficiently cooled, and the inconvenience of a thermal chain reaction to other cells can be prevented. Therefore, it is possible to appropriately cool the battery module without affecting the refrigerant gas. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a plan view of the battery module and the cooler. [Diagram 2] FIG. 13 is a diagram showing an example of a burst structure. [Diagram 3] FIG. 13 is a diagram showing an example in which a cell is expanded. [Figure 4] This is an example in which the thickness of the cooling plate is changed. [Diagram 5] This is an example in which a plurality of sharp projections are provided. [Figure 6] 13A and 13B are diagrams showing the bursting structure of another embodiment. [Figure 7] 13A and 13B are diagrams showing the bursting structure of another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The cooler according to the present invention is capable of cooling a battery module having a plurality of cells. The cooler 1 according to the present embodiment will be described below. However, the cooler 1 is not limited to the following embodiment, and various modifications are possible without departing from the gist of the present invention.

[0014] Fig. 1 is a plan view of a cooler 1 and a battery module 2 cooled by the cooler 1. As shown in Fig. 1, the battery module 2 is provided in a battery pack 10, and has a plurality of cells 3 arranged with the cooler 1 interposed therebetween (sandwiched therebetween).

[0015] In the following description, the direction parallel to the direction in which the cells 3 and the cooler 1 face each other in a plan view of the battery module 2 is defined as the X direction, and the direction perpendicular to the X direction in a plan view of the battery module 2 is defined as the Y direction. Also, the direction perpendicular to both the X direction and the Y direction is defined as the Z direction. Furthermore, one side in the X direction is defined as the X1 side, and the other side in the X direction is defined as the X2 side.

[0016] 1, two battery modules 2 are arranged side by side along the Y direction. In the following description, when it is necessary to distinguish between the two battery modules 2, one will be referred to as battery module 2A and the other as battery module 2B.

[0017] The battery module 2 has a plurality of cells 3 arranged along the X direction (one example of the "first direction"). In this embodiment, a plurality of cells 3 (three in this embodiment) are arranged along the X direction. In the following, when the three cells 3 are to be distinguished from one another, they will be described as cell 3A, cell 3B, and cell 3C. The cell 3 is formed in a quadrangular prism shape, and has a positive electrode 11A and a negative electrode 11B at the top. Although not shown in the figure, the plurality of cells 3 are connected to one another in series or in parallel.

[0018] A cooling plate 20 is provided between the side surfaces of two cells 3 adjacent to each other along the X direction. The two cells 3 adjacent to each other along the X direction correspond to cells 3A and 3B, and cells 3B and 3C. The side surface of the cell 3 corresponds to a surface perpendicular to the X direction, that is, a surface parallel to the YZ plane, among the surfaces of the cell 3 formed in a quadrangular prism shape. In this embodiment, the cooling plate 20 is provided between the side surface of the cell 3A and the side surface of the cell 3B, and between the side surface of the cell 3B and the side surface of the cell 3C. In this embodiment, the cooling plate 20 extends along the Y direction. Therefore, a single cooling plate 20 is provided between the side of cell 3A and the side of cell 3B of battery module 2A and between the side of cell 3A and the side of cell 3B of battery module 2B, and a single cooling plate 20 is provided between the side of cell 3B and the side of cell 3C of battery module 2A and between the side of cell 3B and the side of cell 3C of battery module 2B. When distinguishing between these two cooling plates 20, the cooling plate 20 provided between the side of cell 3A and the side of cell 3B will be described as cooling plate 20A, and the cooling plate 20 provided between the side of cell 3B and the side of cell 3C will be described as cooling plate 20B.

[0019] The cooling plate 20 is provided on the cell 3 via a heat transfer sheet 4. That is, the cooling plate 20 is provided between the side surfaces of two adjacent cells 3, sandwiched between the heat transfer sheets 4 from both outer sides in the X direction. The heat transfer sheet 4 is made of a material having high thermal conductivity and adhesion, such as rubber or gel. By bringing such a heat transfer sheet 4 into close contact with each of the cooling plate 20 and the cell 3, the heat generated in the cell 3 is efficiently transferred to the cooling plate 20 via the heat transfer sheet 4. Therefore, it is possible to cool a plurality of cells 3 of the battery module 2. The cooling plate 20 and the cell 3, which are in close contact with each other via the heat transfer sheet 4, are sandwiched between a pair of plate members 7 from both outer sides in the X direction via a buffer sheet 5 and a heat insulating sheet 6. The pair of plate members 7 is fastened and fixed by a bolt 8A and a nut 8B. The cooling plate 20 and the cell 3, which are in close contact with each other via the heat transfer sheet 4 and are sandwiched between a pair of plate members 7 in this way, are housed in a housing 9 with a bottom.

[0020] The cooling plate 20 has a flow path 21 (see FIG. 2) through which an insulating coolant flows. As described above, in this embodiment, the cooling plate 20 is provided extending along the Y direction. Therefore, the flow path 21 also extends along the Y direction, and the coolant flows along the Y direction. The insulating coolant is a coolant having a resistance value of, for example, several megaohms to several tens of megaohms or more. The coolant is configured to circulate between the heat exchanger and the cooling plate 20 by a pump (not shown). As a result, the battery module 2 is cooled by the cooler 1.

[0021] Here, if some abnormality occurs and the cell 3 generates heat, it expands. Therefore, the cooling plate 20 is provided with a burst structure D (see FIG. 2) that leaks the coolant from the flow path 21 in response to the expansion of the cell 3. By leaking the coolant from the flow path 21, the coolant is sprayed onto the expanding cell 3, and the sprayed coolant takes heat from the cell 3. This makes it possible to suppress the heat generation of the cell 3. The coolant leaked from the cooling plate 20 does not only come into contact with the expanded cell 3, but accumulates in the housing 9. As a result, the other cells 3 different from the expanded cell 3 are also immersed in the coolant and cooled. Therefore, the heat generation of not only the expanded cell 3 is suppressed, but the heat generation of all the cells 3 accommodated in the housing 9 is suppressed. As described above, the heat transfer sheet 4 is provided on the side of the cell 3, but the heat transfer sheet 4 is one that softens (melts) and does not come into close contact with the cell 3 at a temperature higher than the temperature of the cell 3 when the battery pack 10 is being used without the cell 3 experiencing thermal runaway and lower than the temperature of the cell 3 when the cell 3 experiences thermal runaway. Therefore, the coolant leaking from the flow path 21 is not prevented from being sprayed onto the cell 3.

[0022] The rupture structure D of this embodiment is shown in Fig. 2. In the example of Fig. 2, the rupture structure D is provided on the cooling plate 20A between the side of the cell 3A and the side of the cell 3B. Although not shown, the rupture structure D is also provided on the cooling plate 20B between the side of the cell 3B and the side of the cell 3C.

[0023] The cooling plate 20A includes a thin portion 23 and a thick portion 24 in an opposing portion 22 that faces the side surface of the cell 3. The thin portion 23 has a first thickness t1, and the thick portion 24 has a second thickness t2. The second thickness t2 is thicker than the first thickness t1. That is, the relationship is first thickness t1<second thickness t2.

[0024] The thin portion 23 is provided in a central region along the Z direction (an example of the "second direction") of the facing portion 22. In this embodiment, as shown in Fig. 2, the thin portion 23 having the first thickness t1 is formed in a central region along the Z direction of the facing portion 22 facing the side surface of the cell 3A in the cooling plate 20A. Also, the thin portion 23 having the first thickness t1 is formed in a central region along the Z direction of the facing portion 22 facing the side surface of the cell 3B in the cooling plate 20A.

[0025] The thick portion 24 is provided on the outer side of the thin portion 23 along the Z direction in the facing portion 22. In this embodiment, as shown in Fig. 2, the thick portion 24 having the second thickness t2 is formed on both outer sides of the thin portion 23 along the Z direction in the facing portion 22 facing the side surface of the cell 3A in the cooling plate 20A. Also, the thick portion 24 having the second thickness t2 is formed on both outer sides of the thin portion 23 along the Z direction in the facing portion 22 facing the side surface of the cell 3B in the cooling plate 20A. The rupture structure D is configured to include the thin portion 23 described above.

[0026] The rupture structure D includes a sharp projection 25 extending along the X direction in the flow path 21 inside the facing portion 22 facing the side surface of the cell 3 in the cooling plate 20A. In this embodiment, the sharp projection 25 is provided extending toward the cell 3A side along the X direction in the flow path 21 inside the facing portion 22 facing the cell 3B in the cooling plate 20A. That is, the sharp projection 25 is provided in a state of extending from the X2 side toward the X1 side. In this embodiment, the sharp projection 25 is integrally formed with a cylindrical portion 25A extending from the facing portion 22 along the X direction and a conical portion 25B provided at the tip of the cylindrical portion 25A. Of course, the sharp projection 25 may be configured in another shape. In addition, the sharp projection 25 may be configured as a wall-like body that extends from the X2 side toward the X1 side and has a predetermined length along the Y direction as long as the tip is sharp.

[0027] 3 shows an example of the case where the cooling liquid leaks when the cell 3A expands. When the cell 3A expands, the opposing portion 22 of the cooling plate 20 that faces the side surface of the cell 3A deforms to approach the cell 3B in response to the expansion of the cell 3A. This deformation causes the thin portion 23 to be damaged (holes are formed) by the sharp protrusions 25, and the cooling liquid leaks from the damaged portion. Therefore, the cooling liquid is sprayed onto the cell 3A, and the cell 3A is cooled.

[0028] Here, when an abnormality occurs in the cell 3, the cell 3 tends to expand on both sides along the X direction, but as described above, the sharp projection 25 is provided so as to extend from the X2 side toward the X1 side. For this reason, as shown in FIG. 4, the facing portion 22 may be provided with a thin portion 23 only on the side from which the sharp projection 25 extends (the X2 side based on the cell 3), and the side from which the sharp projection 25 extends (the X1 side based on the cell 3) may be configured to have a constant thickness. As a result, as shown in FIG. 4, when an abnormality occurs in the cell 3, the cell 3 expands only on the side from which the sharp projection 25 extends (the X2 side based on the cell 3), and the expansion on the side from which the sharp projection 25 extends (the X1 side based on the cell 3) can be suppressed. Therefore, the coolant can be leaked from the side from which the sharp projection 25 extends (the X2 side based on the cell 3), and the coolant can be prevented from leaking from the side from which the sharp projection 25 extends (the X1 side based on the cell 3). In this case, a cooling plate 20 may also be provided on the side of cell 3C opposite to cell 3B, and this cooling plate 20 may be provided with a sharp projection 25 extending toward cell 3C.

[0029] In addition, when the cell 3 expands, the deformation amount of the central region in the Z direction of the facing portion 22 is large, and the deformation amount of the regions on both sides of the central region in the Z direction is small. Therefore, it is also possible to provide a plurality of sharp-pointed protrusions 25 so that the cooling water leaks from the central region and both outer regions in the Z direction according to such deformation amount. In this case, as shown in FIG. 5, a plurality of sharp-pointed protrusions 25 are provided along the Z direction in the flow passage 21 inside the facing portion 22, and the length of the sharp-pointed protrusions 25 provided in the central region along the Z direction is formed shorter than the length of the sharp-pointed protrusions 25 provided outside the central region along the Z direction. In addition, the length of the sharp-pointed protrusions 25 provided in the central region along the Z direction and the length of the sharp-pointed protrusions 25 provided outside the central region along the Z direction are set according to the deformation amount of the facing portion 22. This makes it possible to leak the cooling water from the flow passage 21 not only from the central region along the Z direction but also outside the central region along the Z direction according to the deformation of the facing portion 22. Therefore, the cooling liquid can be leaked at a plurality of locations that are different from each other in the Z direction, so that the cooling effect can be improved.

[0030] The above describes an embodiment of the cooler 1. According to the above-described cooler 1, the coolant leaks into the battery case that houses the battery module 2, and the other non-expanded cells 3 are immersed in the coolant, thereby cooling the other cells 3, thereby preventing any inconvenience to the other cells 3.

[0031] Other embodiments Next, other embodiments of the cooler 1 will be described.

[0032] In the above embodiment, the cooling plate 20 has been described as including the thin portion 23 having the first thickness t1 and the thick portion 24 having the second thickness t2 that is thicker than the first thickness t1. However, the cooling plate 20 may be configured to have a uniform thickness.

[0033] In the above embodiment, the rupture structure D has been described as including the sharp protrusion 25 extending along the X direction in the flow path 21 inside the facing portion 22 facing the side surface of the cell 3 in the cooling plate 20. However, the rupture structure D can be configured without including the sharp protrusion 25. In this case, as shown in FIG. 6A, the cooling plate 20 is configured to include a thin portion 23 having a first thickness t1 and a thick portion 24 having a second thickness t2 thicker than the first thickness t1, and as shown in FIG. 6B, the stress generated in the cell 3 when the temperature of the cell 3 reaches a predetermined value may be configured to exceed the breaking strength of the thin portion 23. This allows the expansion of the cell 3 to break the thin portion 23 and leak the coolant.

[0034] Also, as shown in Fig. 7, for example, it is possible to configure the thin portion 23 of the cooling plate 20 with different materials from the other portions of the thin portion 23. In this case, as shown in Fig. 7(A), the other portions of the cooling plate 20 are configured with metal, and the thin portion 23 is configured with resin, and as shown in Fig. 7(B), it is preferable to configure the temperature of the resin that configures the thin portion 23 to exceed its melting point when the temperature of the cells 3 reaches a predetermined value. This makes it possible to damage the cooling plate 20 and leak the coolant when the cells 3 expand.

[0035] In the above embodiment, an example was given of a case where the battery pack 10 is provided with two battery modules 2, but the battery pack 10 may be provided with one battery module 2, or may be provided with three or more battery modules 2.

[0036] In the above embodiment, the second direction is described as the Z direction, but the second direction may be the Y direction. In this case, the sharp projections 25 are arranged side by side in the flow path 21 along the direction in which the coolant flows.

[0037] [Summary of the above embodiment] The above-described cooler 1 will now be outlined.

[0038] (1) The cooler 1 cools a battery module 2 having a plurality of cells 3 arranged along an X direction (first direction), and includes a cooling plate 20 provided between side surfaces of two adjacent cells 3 along the X direction. The cooling plate 20 has a flow path 21 therein through which an insulating cooling liquid flows, and is provided with a rupture structure D that causes the cooling liquid to leak from the flow path 21 in response to expansion of the cells 3.

[0039] According to this configuration, the cells 3 can be cooled from the sides by the coolant flowing through the flow paths 21 in the cooling plate 20. In addition, since the coolant is configured to leak from the flow paths 21 when the cells 3 expand, the coolant is sprayed onto the expanded cells 3, and the temperature rise of the expanded cells 3 can be suppressed in a focused manner. As a result, only the expanded cells 3 can be efficiently cooled, and the inconvenience of a thermal chain reaction to other cells 3 can be prevented. Therefore, it is possible to appropriately cool the battery module 2 without affecting the refrigerant gas.

[0040] (2) In the cooler 1 described in (1), the cooling plate 20 preferably includes a thin portion 23 having a first thickness t1 provided in a central region along the Z direction (second direction) perpendicular to the X direction of the opposing portion 22 facing the side of the cell 3, and a thick portion 24 having a second thickness t2 thicker than the first thickness t1 provided outside the thin portion 23 along the Z direction of the opposing portion 22, and the rupture structure D is preferably configured to include the thin portion 23.

[0041] When the cell 3 expands, the central portion of the side surface of the cell 3 protrudes the most. Therefore, with the above-described configuration, the most protruding portion of the side surface of the cell 3 presses the thin-walled portion 23, making it easier to damage the thin-walled portion 23. Therefore, the cooling liquid is sprayed onto the expanded cell 3, making it possible to suppress the temperature rise of the cell 3.

[0042] (3) In the cooler 1 described in (1) or (2), it is preferable that the rupture structure D includes a sharp protrusion 25 extending along the X direction within the flow path 21 inside the facing portion 22 that faces the side surface of the cell 3 in the cooling plate 20.

[0043] According to this configuration, the flow paths 21 can be easily damaged by the sharp projections 25 in response to the expansion of the cells 3. Therefore, it is possible to spray a cooling liquid onto the expanded cells 3 and suppress the temperature rise of the cells 3.

[0044] (4) The cooler 1 described in (3) is preferably provided with a plurality of sharp protrusions 25 along a Z direction perpendicular to the X direction within the flow path 21 inside the opposing portion 22, and the length of the sharp protrusions 25 provided in a central region along the Z direction is shorter than the length of the sharp protrusions 25 provided outside the central region along the Z direction.

[0045] According to this configuration, when the cell 3 expands, the length of the sharp projections 25 at the center of the side surface of the cell 3 where they protrude the most can be shortened, and the length of the sharp projections 25 at the outer side surfaces of the cell 3 rather than at the center can be lengthened. Therefore, when the cell 3 expands, the sharp projections 25 can damage the flow paths 21 not only at the center of the side surface of the cell 3 but also on the outer side, allowing the coolant to be sprayed over the entire side surface of the cell 3, thereby enhancing the effect of suppressing the temperature rise of the cell 3. [Industrial Applicability]

[0046] The technology according to the present disclosure can be used in a cooler that cools a battery module having a plurality of cells. [Explanation of symbols]

[0047] 1: cooler, 2: battery module, 3: cell, 20: cooling plate, 21: flow path, 22: facing portion, 23: thin portion, 24: thick portion, 25: sharp projection, D: burst structure, t1: first thickness, t2: second thickness

Claims

1. A cooler for cooling a battery module having a plurality of cells arranged along a first direction, a cooling plate provided between side surfaces of two of the cells adjacent to each other along the first direction; the cooling plate has a flow path therein through which an insulating cooling liquid flows; The cooler is provided with a bursting structure that allows the coolant to escape from the flow passages in response to expansion of the cells.

2. The cooling plate includes a thin portion having a first thickness provided in a central region along a second direction perpendicular to the first direction in an opposing portion facing the side surface of the cell, and a thick portion having a second thickness thicker than the first thickness provided outside the thin portion along the second direction in the opposing portion, The cooler according to claim 1 , wherein the rupture structure comprises the thinned portion.

3. The cooler according to claim 1 or 2, wherein the rupture structure includes a sharp protrusion extending along the first direction within the flow passage inside a facing portion of the cooling plate facing the side surface of the cell.

4. a plurality of the sharp projections are provided in the flow passage inside the opposing portion along a second direction perpendicular to the first direction, The cooler according to claim 3 , wherein a length of the sharp-pointed protrusion provided in a central region along the second direction is shorter than a length of the sharp-pointed protrusion provided outside the central region along the second direction.

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