Battery pack

Abstract

To prevent a battery cell from interfering with a case even when a load is input from a direction perpendicular to a stacking direction of a battery module.SOLUTION: A battery pack comprises: a battery module including a stacked body in which a plurality of battery cells are stacked; and a case housing the plurality of battery modules. The plurality of battery modules are arranged side by side in a width direction of the case inside the case. The battery pack includes a heat shield plate disposed between adjacent battery modules and facing an entire side surface of the battery module. In the battery module disposed at least on the outermost side in a width direction of the case among the plurality of battery modules, the battery cell located at a center in the stacking direction of the stacked body is fixed to the heat shield plate.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Patent Document 1 discloses a battery pack in which battery modules, each of which has a plurality of stacked battery cells, are housed in a case in a state where they are arranged in multiple rows. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-107092 Summary of the Invention [Problem to be solved by the invention]

[0004] When a load acts on the battery pack in a direction perpendicular to the stacking direction of the battery modules, the battery cells may protrude in the width direction of the case and interfere with the case. If the battery cells interfere with the inner surface of the case, they will deform. Since battery cell deformation can lead to smoke or fire, it is desirable to prevent battery cell deformation.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a battery pack that can prevent battery cells from interfering with the case even when a load is input from a direction perpendicular to the stacking direction of the battery modules. [Means for solving the problem]

[0006] The present invention is a battery pack comprising a battery module including a stack of multiple battery cells, and a case that houses multiple battery modules, wherein multiple battery modules are arranged side by side inside the case in the width direction of the case, and wherein a heat shield is disposed between adjacent battery modules and faces the entire side of the battery modules, and wherein, of the multiple battery modules, at least the battery module that is disposed outermost in the width direction of the case has the battery cell located at the center of the stack in the stacking direction fixed to the heat shield. [Effects of the Invention]

[0007] In the present invention, even when a load is applied from a direction perpendicular to the stacking direction of the battery modules, interference between the battery cells and the case can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a vehicle equipped with a battery pack according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the structure of the battery pack. [Figure 3] FIG. 3 is a diagram for explaining the positional relationship between the inner surface of the case and the battery module. [Figure 4] FIG. 4 is a diagram for explaining a side collision of a vehicle. [Figure 5] FIG. 5 is a diagram for explaining a case where a load due to a side collision acts on a battery pack. [Figure 6] FIG. 6 is a diagram showing a state of the battery pack when a load is input due to a side collision. [Figure 7] FIG. 7 is a diagram for explaining the structure of a battery pack of a comparative example. [Figure 8] FIG. 8 is a diagram for explaining the positional relationship between the inner surface of the case and the battery module in the comparative example. [Figure 9]FIG. 9 is a diagram for explaining a case where a load due to a side collision acts on a battery pack in the structure of the comparative example. [Figure 10] FIG. 10 is a diagram showing a state when a load is input in a side collision in a battery pack of a comparative example.

[0009] The battery pack according to the embodiment of the present invention will be specifically described below, but the present invention is not limited to the embodiment described below.

[0010] Fig. 1 is a schematic diagram showing a vehicle equipped with a battery pack according to an embodiment. The battery pack 1 is mounted on the vehicle Ve. The vehicle Ve runs using the power stored in the battery pack 1. The battery pack 1 includes a case 2 and a plurality of battery modules 3. Fig. 1 shows a top view of the vehicle Ve.

[0011] The case 2 is a battery pack case attached to the body of the vehicle Ve. The case 2 houses multiple battery modules 3. Inside the case 2, the multiple battery modules 3 are arranged side by side in the width direction of the case 2. As shown in FIG. 2, the case 2 houses four battery modules 3A, 3B, 3C, and 3D. From left to right in the vehicle width direction, the first battery module 3A, the second battery module 3B, the third battery module 3C, and the fourth battery module 3D are arranged in this order. When the case 2 is mounted on the vehicle Ve, the width direction of the case 2 is the same as the width direction (vehicle width direction) of the vehicle Ve, and the length direction of the case 2 is the same as the front-to-rear direction of the vehicle Ve. The left side in the vehicle width direction is the left side when the vehicle Ve is facing forward (FR direction). In this description, when there is no need to distinguish between the first to fourth battery modules 3A to 3D, they will simply be referred to as battery modules 3.

[0012] As shown in FIG. 2, the battery pack 1 includes heat shields 4 arranged between the battery modules 3. The heat shields 4 are components for preventing heat from being received by adjacent battery modules 3 in the event of thermal runaway in a battery cell 5 (shown in FIG. 3, etc.). The heat shields 4 extend along the stacking direction of the battery modules 3 and are formed to face the entire side surfaces of the battery modules 3. The heat shields 4 are fixed to the case 2. A first heat shield 4A is arranged between the first battery module 3A and the second battery module 3B. A second heat shield 4B is arranged between the second battery module 3B and the third battery module 3C. A third heat shield 4C is arranged between the third battery module 3C and the fourth battery module 3D. Note that FIG. 2 shows a top view of the battery pack 1. In this description, the first to third heat shields 4A to 4C will be simply referred to as heat shields 4 unless they are to be distinguished from one another.

[0013] As shown in FIG. 3 , the battery module 3 has a stack 6 in which multiple battery cells 5 are stacked, a pair of end plates 7A, 7B, and an intermediate plate 8. The stack 6 has a layered structure in which the battery cells 5 and resin frames are arranged alternately. The pair of end plates 7A, 7B are arranged at both ends of the stack 6 in the stacking direction. The intermediate plate 8 is arranged in the middle of the battery module 3. The end plate 7 and the intermediate plate 8 are fixed to the case 2. In this description, when there is no need to distinguish between one end plate 7A and the other end plate 7B, they will simply be referred to as end plate 7.

[0014] The battery module 3 has a structure in which the stack 6 is sandwiched between end plates 7 and restraint bands in the stacking direction. Two restraint bands are arranged above and below the stack 6, extending in the stacking direction to connect the pair of end plates 7A, 7B. One end of the restraint band is fixed to one end plate 7A, and the other end of the restraint band is fixed to the other end plate 7B. In the battery module 3, the restraint bands restrict the up and down movement of the battery cells 5. Note that the restraint bands are not shown in Figure 3 etc.

[0015] Here, the structure of the battery pack 1 will be compared with that of a comparative battery pack 100. Figures 7 to 10 show the comparative battery pack 100. As shown in Figures 7 and 8, in the comparative battery pack 100, the battery cells 5 of the battery module 103 are not bonded to the heat shield 104. The first heat shield 104A is disposed between the first battery module 103A and the second battery module 103B, and is disposed so as to cover the second battery module 103B. As shown in Figures 8 and 9, when a load due to a side collision acts on the battery pack 100 as an input to the vehicle, the battery cells 105 of the first battery module 103A protrude in the width direction, and the central battery cell 105A interferes with the inner surface 102a of the case 102. As shown in Figure 10, the second battery module 103B is tightly held between the first heat shield 104A and the second heat shield 104B, and the third battery module 103C is tightly held between the second heat shield 104B and the third heat shield 104C, so there is no bellows deformation or interference. However, the first battery module 103A and the fourth battery module 103D undergo bellows deformation due to inertia during a side impact such as a collision. As a result, interference occurs between the first battery module 103A and the inner surface 102a of the case 102, and interference occurs between the fourth battery module 103D and the inner surface 102a of the case 102.

[0016] On the other hand, in the battery pack 1, the first heat shield 4A is arranged to cover the first battery module 3A. In the example, the arrangement of the first heat shield 4A is changed from that of the comparative example. In addition, in the battery pack 1, the side surface of the battery module 3 and the heat shield 4 are adhesively fixed.

[0017] As shown in FIG. 2 , the side of the first battery module 3A is fixed to the first heat shield 4A with adhesive 9. Similarly, the side of the fourth battery module 3D is fixed to the third heat shield 4C with adhesive 9. Furthermore, the side of the third battery module 3C is fixed to the second heat shield 4B with adhesive 9. The second battery module 3B is sandwiched between the first heat shield 4A and the second heat shield 4B but is not fixed to the heat shield 4. Because the gap between the battery modules 3 is narrow, the installation of the heat shield 4 almost completely eliminates the gap. Therefore, since the second battery module 3B is sandwiched between the first heat shield 4A and the second heat shield 4B and does not move in the width direction, it does not matter if it is not adhesively fixed to the heat shield 4. The first battery module 3A and the fourth battery module 3D are always adhesively fixed to the heat shield 4. Either the second battery module 3B or the third battery module 3C is adhesively fixed to the heat shield 4. In the battery pack 1, at least in the battery module arranged outermost in the width direction of the case 2 among the multiple battery modules 3, the battery cell 5 located at the center of the stack 6 in the stacking direction is fixed to the heat shield 4.

[0018] As shown in FIG. 3, adhesive 9 is applied between the first battery module 3A and the first heat shield 4A, and the battery cells 5 of the first battery module 3A are adhered and fixed to the first heat shield 4A. The battery cells 5 are adhered to the heat shield 4 with a minimum amount of adhesive applied. Of the multiple battery cells 5 included in the first battery module 3A, adhesive 9 is applied only to the central battery cell 5A, which is the cell that will protrude the most in the width direction during a side collision. The battery cell 5 to be adhered is the central battery cell 5A. The central battery cell 5A is the battery cell that is located in the center of the stacking direction among the battery cells 5 arranged between the end plate 7 and the intermediate plate 8.

[0019] For example, if ten battery cells 5 are stacked between a pair of end plates 7A and 7B, five battery cells 5 are stacked between one end plate 7A and the intermediate plate 8, and five battery cells 5 are stacked between the other end plate 7B and the intermediate plate 8. In this case, there are two central battery cells 5A: one battery cell 5 located in the center of the stacking direction between one end plate 7A and the intermediate plate 8, and another battery cell 5 located in the center of the stacking direction between the other end plate 7B and the intermediate plate 8. Adhesive 9 is applied only to the two battery cells 5 that make up the central battery cells 5A. As shown in Figure 4, it is assumed that a vehicle Ve is subjected to a side collision. By adhesively fixing only the most protruding central battery cell 5A to the heat shield 4, interference with the case 2 due to bellows deformation of the stack 6 can be prevented. Because the central battery cell 5A is fixed to the heat shield 4, the entire battery module 3 moves in the load input direction, as shown in Figure 5. As a result, the battery module 3 does not bellows, and the battery cells 5 do not interfere with the case 2, as shown in Figure 6.

[0020] As described above, according to the embodiment, when a load acts on the battery pack 1 from a direction perpendicular to the stacking direction of the battery modules due to a side collision of the vehicle Ve, for example, it is possible to prevent the battery cells 5 from interfering with the inner surface 2a of the case 2. [Explanation of symbols]

[0021] 1 battery pack 2 cases 3 Battery Module 4 Heat shield 5 battery cells 6 Laminate 7 End Plate 8 Intermediate Plate 9. Adhesive

Claims

[Claim 1] a battery module including a stack of a plurality of battery cells; a case that houses a plurality of the battery modules; Equipped with a battery pack in which a plurality of the battery modules are arranged side by side in a width direction of the case inside the case, a heat shield plate disposed between adjacent battery modules and facing the entire side surface of the battery module; In at least one battery module among the plurality of battery modules that is arranged outermost in the width direction of the case, the battery cell that is located at the center of the stack in the stacking direction of the stack is fixed to the heat shield plate. A battery pack characterized by:

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