Battery module and battery pack

Abstract

To provide a battery module that reduces the thermal impact on battery cells arranged adjacent to each other.SOLUTION: In a battery pack 10, a battery module 20 includes first battery cells 22a and a second battery cell 22b which are battery cells 22 arranged adjacent to each other, and a heat pipe 24 arranged between the first battery cell and the second battery cell and in contact with at least the first battery cell. Each heat pipe 24 is arranged such that the surface of one end (evaporator side) is in contact with the surface of the battery cell 22, and the other end (condenser side) is arranged in the z-axis direction so as to extend toward a cooler 14 and a heat diffusion plate 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery module and a battery pack in which the battery module is enclosed. [Background technology]

[0002] Patent Document 1 discloses a battery module including a heat spreader sheet and a heat insulating material between a plurality of cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2022-549926 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, if one battery cell generates abnormal heat for some reason, the thermal effect on the adjacent battery cells is large, and this thermal effect is not desirable for the adjacent battery cells.

[0005] In view of the above problems, the present disclosure aims to provide a battery module that can reduce the thermal impact on adjacent battery cells, and also to provide a battery pack that includes such a battery module. [Means for solving the problem]

[0006] The present application discloses a battery module comprising a first battery cell, a second battery cell adjacent to the first battery cell, and a heat pipe disposed between the first battery cell and the second battery cell and in contact with at least the first battery cell.

[0007] The heat pipes are arranged on one side and the other side of the first battery cell, sandwiching the first battery cell, and the heat pipe arranged on one side and the heat pipe arranged on the other side may be arranged so that they are in different positions on opposite sides of each other.

[0008] The first battery cell and the second battery cell may be configured to have a rectangular parallelepiped shape, and the heat pipe may have a rectangular prism-like outer shape.

[0009] The first battery cell and the second battery cell may be cylindrical, and the heat pipe may have a cylindrical outer shape.

[0010] The present application also discloses a battery pack including the above battery module and a cooler, in which the heat pipe of the battery module is connected to the cooler directly or via a heat diffusion plate. [Effects of the Invention]

[0011] According to the present disclosure, heat generated in the target battery cell (first battery cell) can be released to a cooler via a heat pipe, thereby reducing the thermal impact on the adjacent battery cell (second battery cell). [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view illustrating the configuration of a battery pack 10. As shown in FIG. [Figure 2] FIG. 2 is a diagram illustrating one battery cell 22 and a heat pipe 24. As shown in FIG. [Figure 3] FIG. 3 is a perspective view illustrating the configuration of the battery pack 30. As shown in FIG. [Figure 4] FIG. 4 is a plan view illustrating the configuration of the battery pack 50. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the following description, a stack of multiple battery cells is bundled together to form a battery module, and multiple battery modules are further stacked and sealed to form a battery pack.

[0014] 1. Form 1 FIG. 1 illustrates a perspective view of a battery pack 10 including a battery module 20 according to the first embodiment (the exterior body is omitted for clarity). In FIG. 1, multiple battery modules 20 (three in this embodiment) are arranged. (Only the battery module 10 on the left side of the page shows its components, while the other two battery modules 10 are simply shown with dotted lines to show only their outer edges.) In the battery module 10 shown on the far left side of the page, some components are hatched, though not in cross section, to make the components easier to distinguish. In addition, FIG. 1 and subsequent figures also show the directions of a three-dimensional Cartesian coordinate system. Here, the x-axis direction is the direction in which battery cells and battery modules are stacked, and the yz plane is the direction of the plate surface of the battery cell when it is plate-shaped. The z-axis is the vertical direction, with the larger z being the upper side.

[0015] 1, the battery pack 10 includes a plurality of battery modules 20, a heat diffusion plate 12, and a cooler 14. Although not shown, the battery pack 10 also includes a bag-shaped exterior body that encloses and seals these components. Each component will be described below.

[0016] 1.1.Battery module As can be seen from FIG. 1, in this embodiment, the battery module 20 is configured to include battery cells 22 and heat pipes 24.

[0017] [Battery cell] The battery cell 22 is a single cell (in this embodiment, a flat (rectangular) shape) that has an overall appearance such as a flat plate, a prismatic column, or a cylindrical column, and when it is a flat plate, it has a front and back surface and a side surface that forms a thickness. The battery cell 22 is as known, and examples thereof include a battery cell that uses an electrolytic solution and a solid-state battery that uses a solid electrolyte in whole or in part. As is well known, the battery cell 22 includes positive and negative electrode current collectors, and positive and negative electrode active material layers, and these are stacked in multiple layers with separators interposed therebetween.

[0018] In this embodiment, three battery cells 22 are arranged adjacent to each other (a first battery cell is represented as battery cell 22a, and a second battery cell adjacent to it is represented as battery cell 22b). The number of battery cells 22 included in one battery module 20 is not particularly limited, and may be two, four or more.

[0019] [Heat pipe] The heat pipe 24 is well known, and may be formed, for example, by a working fluid sealed in a tubular member with both ends sealed. This working fluid receives heat from a heat source (battery cells 22 in this embodiment) and evaporates into a gas within the tube, and moves (diffuses) the heat as it travels through the tube. As the gas moves or at its destination (thermal diffusion plate 12 in this embodiment), heat is lost and it condenses into a liquid, and the liquid working fluid returns to the location where the heat source (battery cells 22 in this embodiment) is located. The heat pipe 24 transfers (diffuses) heat through such movement of the working fluid accompanied by a phase change. Note that the inner surface of the tube may be provided with fine flow paths (wicks or fine grooves) for the condensed liquid to facilitate the return of the condensed liquid to the heat source.

[0020] The operating temperature of the heat pipe 24 can be adjusted by the physical properties of the working fluid. In this embodiment, naphthalene can be used as the working fluid, as the heat pipe 24 operates in the range of 200°C to 400°C, thereby enhancing cooling performance especially during abnormal heating. Furthermore, the material forming the heat pipe 24 is preferably stainless steel in terms of thermal conductivity, strength, and the environment in which it is used.

[0021] The cross-sectional shape of the heat pipe 24 (cross-sectional shape of the pipe) is not particularly limited, but may be rectangular, circular, or flat. However, a rectangular or flat shape is preferable because it is preferable that the outer surface of the heat pipe 24 contacts the surface of the battery cell 22 over a wide area. In this embodiment, the battery cell 22 is flat (rectangular parallelepiped), so the outer shape of the heat pipe 24 is a rectangular column.

[0022] [Battery module configuration] The above battery cells 22 and heat pipes 24 are combined as follows to form a battery module 20. Figure 2 shows one battery cell 22 (first battery cell 22a) of one battery module 20 extracted from Figure 1 and the heat pipe 24 for cooling it.

[0023] As can be seen from Fig. 1, the battery module 20 has multiple battery cells 22 (first battery cell 22a, second battery cell 22b) arranged in the x-axis direction. As can be seen from Figs. 1 and 2, multiple heat pipes 24 are arranged for each battery cell 22. Therefore, in the battery module 20, multiple heat pipes 24 are provided between the first battery cell 22a and the second battery cell 22b.

[0024] Looking at each battery cell 22, as shown in FIG. 2, in this embodiment, three heat pipes 24 are arranged on each of the front and back sides of the battery cell 22 (first battery cell 22a) (on one side and the other side of the battery cell 22). Each heat pipe 24 is positioned so that the surface of one end (evaporator side) is in contact with the surface of the battery cell 22, and the other end (condenser side) is positioned so that it extends toward the cooler 14 (in the z-axis direction in this embodiment). The contact portions between the battery cells 22 and the heat pipes 24 can be made to contact with each other via a heat transfer paste or the like to facilitate heat transfer. On the other hand, the surface of the heat pipe 24 facing the adjacent battery cell 22 (second battery cell 22b) preferably does not contact the second battery cell 22b, or may contact the second battery cell 22b via a heat insulating material, because it is preferable that the heat from the first battery cell 22a is not transferred to the second battery cell 22b easily.

[0025] It is preferable that the multiple heat pipes 24 are arranged at equal intervals relative to one battery cell 22. This can improve the uniformity of cooling. For example, when heat pipes 24 are arranged on both the front and back sides of the battery cell 22, the heat pipes 24 on the front and back can be arranged alternately so that their positions in the y-axis direction do not overlap in a plan view (viewed from above in the z-axis direction). In other words, the heat pipes 24 arranged on one side of the battery cell 22 and the heat pipes 24 arranged on the other side can be arranged so that they are in different positions on opposite sides of each other.

[0026] 1.2.Heat diffusion plate 1, the heat diffusion plate 12 is a plate-shaped member that has the function of widely diffusing heat. Therefore, the heat diffusion plate 12 can be made of a material with high thermal conductivity, such as a metal, and specific examples include copper, aluminum, and stainless steel. Furthermore, since it is preferable that the heat diffusion plate 12 has a certain level of heat capacity, it is preferable that the thickness thereof is set to 1 mm to 2 mm.

[0027] 1.3.Cooler The cooler 14 is a device that finally releases the heat that has reached it to the outside. The specific form of the cooler 14 is not particularly limited, but for example, the cooler 14 can be configured to have a cooling plate as a heat exchanger having a water channel through which cooling water flows, and by running the cooling water through the cooling plate, heat can be released to the outside through the cooling water.

[0028] 1.4.Battery Pack Configuration The battery pack 10 having the above-described configuration is formed by combining the components as follows, for example. As can be seen from FIG. 1, in the battery pack 10, a plurality of battery modules 20 are stacked in the x-axis direction, and in this embodiment, the heat pipes 24 extend downward (downward in the z-axis direction) so as to protrude downward. The protruding tip (lower end in this embodiment) of the heat pipe 24 is in contact with the heat diffusion plate 12 so that heat can be transferred. In order to increase the contact area between the heat pipe 24 and the heat diffusion plate 12 and facilitate heat transfer, the end of the heat pipe 24 may be bent or a heat transfer paste or the like may be placed therebetween. The cooler 14 is arranged to be in contact with the surface of the heat diffusion plate 12 opposite to the side in contact with the heat pipe 24. To improve heat transfer performance, it is preferable that the contact area between the heat diffusion plate 12 and the cooler 14 is large and that the contact thermal resistance is small. Therefore, the heat diffusion plate 12 and the cooler 14 may be overlapped with a heat transfer paste interposed therebetween.

[0029] The components thus assembled are then sealed in a bag-shaped exterior body (not shown) to form the battery pack 10.

[0030] 1.5. Effects etc. According to the battery module 20 and the battery pack 10 including the same, when an internal short circuit or the like occurs in a certain battery cell 22, causing an abnormal temperature rise, the heat can be discharged to the outside through the heat pipe 24, thereby reducing the thermal impact on the adjacent battery cell 22, preventing the adjacent battery cell 22 from being heated and causing a chain reaction of abnormal temperature rises, and even if a chain reaction does occur, the speed of propagation can be slowed.

[0031] In this embodiment, the heat diffusion plate 12 and the cooler 14 are disposed below the battery module 20, but instead, the heat diffusion plate 12 and the cooler 14 may be disposed above the battery module 20 (the larger one in the z-axis direction). In this case, the end of the heat pipe 24 protrudes so as to extend above the battery cell 22, with the heat diffusion plate 12 disposed at the tip, and the cooler 14 disposed above that. This allows the condensed liquid to move easily due to gravity inside the heat pipe 24 and return easily to the end on the side of the battery cell 22, which is the heat source, thereby improving the efficiency of heat transfer.

[0032] In addition, in this embodiment, the heat pipe 24 is connected to the cooler 14 via the heat diffusion plate 12, but this is not limited to this, and the heat pipe 24 may be in direct contact with the cooler 14 without providing the heat diffusion plate 12.

[0033] 2. Form 2 3 is a perspective view of the exterior of a battery pack 30 (excluding the exterior) including a battery module 40 according to form 2. FIG. 3 is shown from the same perspective and in the same display mode as FIG. Battery pack 30 is an example in which a battery module 40 is used instead of battery module 20 of battery pack 10. Furthermore, this battery module 40 uses a heat pipe 44 instead of the heat pipe 24. That is, in this embodiment, the heat pipe is different from embodiment 1, but the other parts are the same, so the same reference numerals are used and descriptions are omitted.

[0034] In the second embodiment, the heat pipes 44 do not protrude from below the battery cells 22, and as a result, the surfaces of the battery cells 22 facing the heat diffusion plate 14 and the lower ends of the heat pipes 44 are arranged to be in contact with the heat diffusion plate 14. Such a battery module 40 and a battery pack 30 including the same also achieve the same effects as those of the first embodiment.

[0035] 3.Form 3 Fig. 4 is a diagram illustrating a battery pack 50 (without the exterior body) including a battery module 60 according to form 3. Fig. 4 is shown in the same manner as Fig. 1, but is a view (plan view) of the battery pack 50 as seen from above in the z-axis direction. In a battery module 60 according to the third embodiment, cylindrical battery cells 62 are used, and heat pipes 24 are arranged between adjacent battery cells 62 so as to be in contact with these battery cells 62. Therefore, the heat pipes 24 according to this embodiment have a cylindrical outer shape, and are configured so that their outer circumferential surfaces are in contact with the outer circumferential surfaces of the cylindrical battery cells 62. Other than this, the battery module 60 can be considered to be the same as the first and second embodiments, and the battery module 60 and the battery pack 50 including the battery module 60 also have the same effects as the first embodiment. [Explanation of symbols]

[0036] 10, 30, 50... battery pack, 12... heat diffusion plate, 14... cooler, 20, 40, 60... battery module, 22... battery cell, 24... heat pipe

Claims

1. a first battery cell; a second battery cell adjacent to the first battery cell; a heat pipe disposed between the first battery cell and the second battery cell and in contact with at least the first battery cell; Battery module.

2. 2. The battery module according to claim 1, wherein the heat pipes are arranged on one side and the other side of the first battery cell, with the first battery cell sandwiched between them, and the heat pipe arranged on the one side and the heat pipe arranged on the other side are arranged at different positions on opposite sides of each other.

3. The battery module according to claim 1 or 2, wherein the first battery cell and the second battery cell have a rectangular parallelepiped shape, and the heat pipe has a rectangular prism shape.

4. The battery module according to claim 1 , wherein the first battery cell and the second battery cell are cylindrical, and the heat pipe has a cylindrical outer shape.

5. The battery module according to claim 1 or 2; a cooler; The heat pipe of the battery module is connected to the cooler directly or via a heat diffusion plate. Battery pack.

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