Battery pack

Abstract

To save a space in a battery pack while properly cooling the cells.SOLUTION: A battery pack 1 includes a plurality of cells 10, tabs 20 connecting the cells 10 to each other, and flow passages 30 formed inside the tabs 20 and through which a coolant for cooling the cells 10 flows.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery pack in which a plurality of battery cells are connected together. [Background technology]

[0002] Patent Document 1 listed below discloses a battery in which a plurality of cells are electrically connected via bus bars. The lower case of this battery is provided with a flow path through which a refrigerant flows to cool the battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-110003 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned battery, the lower case with the flow paths is located away from the connection between the cells and the busbar, which is prone to heat generation, making it difficult to effectively cool the cells. In addition, the space required for the lower case hinders efforts to reduce the battery's space.

[0005] The present invention has been made in consideration of these points, and has an object to appropriately cool cells while reducing the space required for a battery pack. [Means for solving the problem]

[0006] In one aspect of the present invention, a battery pack is provided that includes a plurality of battery cells, tabs that connect the battery cells to each other, and a flow path portion formed inside the tabs and through which a coolant that cools the battery cells flows.

[0007] The flow path portion may be formed inside the tab that is in contact with an outer peripheral surface of the battery cell.

[0008] The flow path portion may be formed from one end to the other end in the axial direction of the battery cell.

[0009] The tab may also have a main body portion in which the flow path portion is formed, and fins extending from the main body portion and in contact with the outer circumferential surface. The fins may cover at least half of the outer circumferential surface.

[0010] The cooling device may further include a supply path for supplying the insulating coolant to each of the flow path portions formed inside the plurality of tabs.

[0011] The coolant may be non-insulating, and both ends of the flow path portion may be closed by the tabs.

[0012] The flow path portion may include a first storage portion that is located at the same position as the outer peripheral surface of the battery cell in the vertical direction and that stores the liquid refrigerant, and a second storage portion that is provided above the battery cell and that is in communication with the first storage portion, and the second storage portion may store the refrigerant that has vaporized in the first storage portion.

[0013] The cooling device may further include a heat exchanger that is provided opposite the second storage portion and that cools the refrigerant stored in the second storage portion. [Effects of the Invention]

[0014] The present invention has the effect of enabling the cells to be appropriately cooled while saving space in the battery pack. [Brief explanation of the drawings]

[0015] [Figure 1]1 is a schematic diagram showing a battery pack 1 according to a first embodiment. [Figure 2] 2 is a schematic diagram showing the configuration of a battery pack 1 having fins 26. FIG. [Figure 3] FIG. 2 is a schematic diagram for explaining the position of the fin 26. [Figure 4] FIG. 2 is a schematic diagram showing a battery pack 1 according to a second embodiment. [Figure 5] 10 is a schematic diagram showing the flow of the refrigerant in the flow path portion 130. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] First Embodiment FIG. 1 is a schematic diagram showing a battery pack 1 according to a first embodiment.

[0017] The battery pack 1 is configured by connecting a plurality of battery cells (simply referred to as cells), which are secondary batteries capable of charging and discharging. The battery pack 1 is, for example, a storage battery mounted on a vehicle. The battery pack 1 has a plurality of cells 10, a plurality of tabs 20, a flow path portion 30, a first tube 40, and a second tube 50.

[0018] The plurality of cells 10 are arranged at predetermined intervals along the arrangement direction in FIG. 1. The plurality of cells 10 may also be arranged at predetermined intervals in a direction perpendicular to the arrangement direction (depth direction in FIG. 1). The shape of the cells 10 here is cylindrical. However, this is not limiting, and the shape of the cells 10 may also be a prism. In the cells 10, the top surface is a positive electrode, and the outer peripheral surface 12 is a negative electrode.

[0019] The multiple tabs 20 are members that connect the multiple cells 10. The multiple tabs 20 are also provided at predetermined intervals along the arrangement direction. Specifically, the tabs 20 are provided between two cells 10 in the arrangement direction. The tab 20 connects the outer peripheral surface 12, which is the negative electrode of one cell 10, to the top surface, which is the positive electrode of the cell 10 adjacent to the one cell 10. As shown in FIG. 1 , the tab 20 includes a shaft portion 22 and an extension portion 24. In this embodiment, the shaft portion 22 corresponds to the main body of the tab 20.

[0020] The shaft portion 22 is positioned parallel to the cylindrical cell 10. The peripheral surface of the shaft portion 22 contacts the negative electrode formed on the outer peripheral surface 12 of the cell 10. For example, the peripheral surface of the shaft portion 22 contacts the outer peripheral surface 12 of the cell 10 from one end to the other in the axial direction. The diameter of the shaft portion 22 is smaller than the diameter of the cell 10. On the other hand, the axial length of the shaft portion 22 is greater than the axial length of the cell 10. Specifically, the shaft portion 22 extends outward beyond both ends of the cell 10 in the axial direction.

[0021] The extension portion 24 extends from the upper end of the shaft portion 22 in a direction perpendicular to the axial direction. The extension portion 24 is located above the upper surface of the cell 10. The extension portion 24 is in contact with the positive electrode formed on the upper surface of the cell 10. Specifically, the extension portion 24 is in contact with the center of the upper surface of the cell 10. The shape of the extension portion 24 when viewed from above is rectangular, but is not limited to this.

[0022] The flow path section 30 is formed inside the tub 20, and is a section through which the refrigerant that cools the cells 10 flows. The refrigerant flows from the upper part (one axial end) of the flow path section 30 to the lower part (the other axial end) as shown by the arrows in FIG. 1 . The upper part of the flow path section 30 is connected to the first pipe 40, and the lower part of the flow path section 30 is connected to the second pipe 50. Therefore, the refrigerant flows from the first pipe 40 into the flow path section 30, and the refrigerant flows from the flow path section 30 to the second pipe 50.

[0023] The flow path portion 30 is formed inside the shaft portion 22 of the tab 20 that is in contact with the outer peripheral surface 12 of the cell 10. In other words, the flow path portion 30 is formed around the connection portion between the cell 10 and the shaft portion 22, where current tends to concentrate and generate heat. This allows the outer peripheral surface 12 of the cell 10 to be cooled by the refrigerant that flows through the flow path portion 30 inside the shaft portion 22. The flow path portion 30 is formed in the center of the shaft portion 22 along the axial direction. The diameter of the flow path portion 30 is, for example, 1 / 3 to 1 / 2 of the diameter of the shaft portion, but is not limited to this.

[0024] The flow path portion 30 is formed in the shaft portion 22 from one end to the other in the axial direction. In other words, the flow path portion 30 is formed from one end to the other end in the axial direction of the cell 10. This allows the refrigerant flowing through the flow path portion 30 to cool a wide range of the outer peripheral surface 12 of the cell 10.

[0025] The first tube 40 is a flow path through which the refrigerant flows toward the flow path portion 30. The first tube 40 functions as a supply path that supplies the refrigerant to each of the flow path portions 30 formed inside the multiple tubs 20. The refrigerant flowing through the first tube 40 is insulating. For example, a pump that pressurizes the refrigerant is provided in the first tube 40, so that the refrigerant can be constantly supplied to the flow path portion 30.

[0026] The second pipe 50 is a flow path through which the refrigerant flowing out from the flow path portion 30 of each tub 20 flows. The second pipe 50 is connected to the first pipe 40 and forms, together with the first pipe 40, a circulation flow path through which the refrigerant circulates. A heat exchanger that cools the refrigerant is provided in the circulation flow path. The heat exchanger may cool the refrigerant with air, or may cool the refrigerant with a lower temperature coolant. In this way, the refrigerant cooled by the heat exchanger flows through the flow path portion 30, allowing the low-temperature refrigerant to cool the cells 10 via the flow path portion 30.

[0027] Incidentally, the tub 20 may have fins 26 to improve the cooling efficiency of the cell 10 . Fig. 2 is a schematic diagram showing the configuration of the battery pack 1 having fins 26. Fig. 3 is a schematic diagram for explaining the position of the fins 26. Region R indicated by a dashed line in Fig. 3 is the position where the fins 26 are provided.

[0028] 2, the fins 26 are provided for each cell 10, and the configuration of the fins 26 of each cell 10 is the same. Therefore, the configuration of one fin 26 will be described below.

[0029] The fins 26 are formed, for example, in a plate shape, and are provided at predetermined intervals in the axial direction in region R shown in Fig. 3. The fins 26 are in contact with the outer peripheral surface 12 of the cells 10 as shown in Fig. 2. Specifically, the fins 26 are in contact with the outer peripheral surface 12 of the cells 10 along the circumferential direction of the cells 10. This makes it easier for heat from the cells 10 to be conducted to the fins 26, and therefore the cells 10 are more easily cooled.

[0030] As shown in Fig. 2, the fins 26 extend from the shaft portion 22 of the tab 20. Specifically, the fins 26 extend from the shaft portion 22 along the outer peripheral surface 12 of the cell 10 with a predetermined curvature. The width of the fins 26 is a constant size here, but is not limited to this. This makes it easier for heat conducted from the cell 10 to the fins 26 to be cooled by the refrigerant flowing through the flow path portion 30.

[0031] Here, the fins 26 cover half of the outer peripheral surface 12 of the cell 10 as shown in Fig. 2, but are not limited thereto and may cover the entire outer peripheral surface 12 of the cell 10. In this way, it is desirable that the fins 26 cover at least half of the outer peripheral surface 12 of the cell 10. Furthermore, as shown in Fig. 3, the fins 26 are provided from one end to the other end in the axial direction of the cell 10. By providing the fins 26 with the above configuration, the fins 26 come into contact with a wide range of the outer peripheral surface 12 of the cell 10, making it easier to cool the cell 10.

[0032] <Second embodiment> The configuration of the battery pack 1 of the second embodiment will be described with reference to FIGS. Fig. 4 is a schematic diagram showing a battery pack 1 according to the second embodiment. Fig. 5 is a schematic diagram showing the flow of the refrigerant in the flow path portion 130.

[0033] In the first embodiment described above, the flow path portion 30 formed in the tub 20 connects the first pipe 40 and the second pipe 50 provided outside the tub 20, and the refrigerant flows from the first pipe 40 into the flow path portion 30, and the refrigerant in the flow path portion 30 flows out to the second pipe 50. In contrast, the flow path portion 130 in the second embodiment is closed by the tub 120, and the refrigerant does not flow into the flow path portion 130. The detailed configurations of the tub 120 and the flow path portion 130 will be described below.

[0034] 4, the tab 120 has a shaft portion 122, a first extending portion 124, and a second extending portion 128. The shaft portion 122 and the first extending portion 124 have the same configuration as the shaft portion 22 and the extending portion 24 described above. The second extending portion 128 extends from the upper end of the shaft portion 122 in a direction perpendicular to the axial direction. The extending direction of the second extending portion 128 is opposite to the extending direction of the first extending portion 124.

[0035] As shown in Fig. 4, the flow path portion 130 is formed inside the shaft portion 122 and the second extension portion 128. The flow path portion 130 is formed in an L-shape to fit the shapes of the shaft portion 122 and the second extension portion 128. The refrigerant inside the flow path portion 130 is non-insulating. The flow path portion 130 is closed at the ends of the shaft portion 122 and the second extension portion 128. This prevents damage to surrounding components due to electrical leakage through the refrigerant.

[0036] As shown in FIG. 5, the flow path section 130 includes a first storage section 132 and a second storage section 134. The first storage section 132 is located at the same position as the outer peripheral surface 12 of the cell 10 in the vertical direction. The first storage section 132 is provided parallel to the outer peripheral surface 12 of the cell 10. The first storage section 132 stores a liquid refrigerant. When cooling the outer peripheral surface 12 of the cell 10, part of the refrigerant in the first storage section 132 is vaporized (evaporated) by the heat of the cell.

[0037] 5, the second storage section 134 is provided above the cell 10. Specifically, the second storage section 134 is located directly above the upper surface of the cell 10. The second storage section 134 communicates with the first storage section 132 and is perpendicular to the first storage section 132. The second storage section 134 stores the refrigerant vaporized in the first storage section 132.

[0038] As shown in Fig. 4 , the battery pack 1 of the second embodiment has a heat exchanger 160 for cooling the gaseous refrigerant in the second housing portion 134. The heat exchanger 160 is provided to face the second housing portion 134. Specifically, the heat exchanger 160 is located above the second extension portion 128 in which the second housing portion 134 is formed. An insulating member 170 is sandwiched between the heat exchanger 160 and the second extension portion 128.

[0039] A coolant having a lower temperature than the refrigerant in the second storage portion 134 flows inside the heat exchanger 160, and the coolant cools the refrigerant in the second storage portion 134. The refrigerant in the second storage portion 134 condenses as it is cooled and becomes liquid. The liquid refrigerant moves to the first storage portion 132 located below the second storage portion 134.

[0040] 4, one heat exchanger 160 faces four tubs 120, but this is not limiting. For example, a heat exchanger 160 may be provided for each tub 120.

[0041] In the second embodiment, the coolant in the flow path portion 130 flows between the first storage portion 132 and the second storage portion 134 as follows. Specifically, the liquid refrigerant in the first storage section 132 is vaporized by heat when cooling the cells 10. The vaporized gaseous refrigerant then moves to the second storage section 134, which is located above the first storage section 132 (specifically, the refrigerant moves in the direction indicated by arrow A in FIG. 5). The gaseous refrigerant that has moved to the second storage section 134 is cooled and condensed by the heat exchanger 160. The condensed liquid refrigerant then moves to the first storage section 132, which is located below the second storage section 134 (specifically, the refrigerant moves in the direction indicated by arrow B in FIG. 5).

[0042] As described above, the refrigerant continues to flow between the first storage section 132 and the second storage section 134 by alternately evaporating and condensing within the flow path section 130. As a result, the temperature of the refrigerant stored in the first storage section 132, which is located at the same position as the outer peripheral surface 12 of the cell 10, can be maintained at a low temperature, so that the cell 10 can continue to be cooled without receiving a new supply of refrigerant from the outside to the flow path section 130.

[0043] <Effects of this embodiment> The battery pack 1 of the above-described embodiment has a tub 20 that connects a plurality of cells 10. Inside the tub 20, a flow path portion 30 is formed through which a refrigerant that cools the cells 10 flows. As a result, the flow path portion 30 formed in the tab 20 connecting the cells 10 can effectively cool the cells 10. In particular, since the flow path portion 30 is provided around the connection portion between the cells 10 and the tab 20 where current tends to concentrate and generate heat, the cells 10 can be cooled more effectively. Furthermore, since the flow path portion 30 is formed inside the tab 20, there is no need to provide additional space for a cooling structure to cool the cells 10. As a result, the battery pack 1 can be made more space-saving while still allowing the cells to be cooled appropriately.

[0044] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0045] 1 battery pack 10 cells 12 Outer surface 20 tabs 22 Shaft 26 Finn 30 Flow path section 40 1st tube 132 First storage unit 134 Second Storage Unit 160 Heat exchanger

Claims

1. a plurality of battery cells; tabs connecting the battery cells to each other; a flow path formed inside the tub through which a coolant for cooling the battery cell flows; A battery pack comprising:

2. the flow path portion is formed inside the tab that is in contact with the outer circumferential surface of the battery cell, The battery pack according to claim 1 .

3. The flow path portion is formed from one end to the other end in the axial direction of the battery cell. The battery pack according to claim 2 .

4. The tab a main body portion having the flow path portion formed therein; fins extending from the main body and in contact with the outer circumferential surface; having The battery pack according to claim 2 .

5. The fins cover more than half of the outer circumferential surface. The battery pack according to claim 4.

6. a supply path for supplying the insulating coolant to each of the flow path portions formed inside the plurality of tabs; The battery pack according to claim 1 .

7. The refrigerant is non-insulating, Both ends of the flow path portion are closed by the tabs. The battery pack according to claim 1 .

8. The flow path portion is a first housing portion that is located at the same position as an outer peripheral surface of the battery cell in the vertical direction and that houses the refrigerant in liquid form; a second housing portion provided above the battery cell and communicating with the first housing portion; The second storage section stores the refrigerant vaporized in the first storage section. The battery pack according to claim 7.

9. The cooling system further includes a heat exchanger that is provided opposite the second storage section and that cools the refrigerant stored in the second storage section. The battery pack according to claim 8.

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