Battery pack

Abstract

To provide a battery pack capable of preventing high-temperature gas discharged from a plurality of battery cells from concentrating in one exhaust path.SOLUTION: A battery pack includes n battery units (n is a natural number equal to or greater than 2) arranged in a predetermined direction, and thermal insulation material installed between the battery units. Each of the battery units has a smoke exhaust valve, and includes m battery cells (m is a natural number equal to or greater than 3) arranged adjacent to each other in a predetermined direction. The battery pack further includes m smoke exhaust ducts. Each of the smoke exhaust ducts is attached to one battery cell in each battery unit, and exhausts gas exhausted from each smoke exhaust valve of the attached n battery cells to the outside of the battery pack.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] JP 2022-74763 A (Patent Document 1) discloses a battery pack including a battery module in which a plurality of battery cells are stacked, each having a smoke exhaust valve and exhausting gas through the smoke exhaust valve, and a smoke exhaust path provided above the smoke exhaust valve of the battery cell. The smoke exhaust path has a plurality of first exhaust paths that guide the gas exhausted from the smoke exhaust valve in a first direction perpendicular to the stacking direction of the battery cells and along the upper surface of the battery cells, and a plurality of second exhaust paths that guide the gas in a second direction opposite to the first direction. In the battery pack, the battery cells with the first exhaust path arranged above and the battery cells with the second exhaust path arranged above are alternately stacked in the stacking direction.

[0003] In this way, in the battery pack of Patent Document 1, two smoke exhaust paths are provided so that the smoke exhaust paths of adjacent battery cells are not the same. With this configuration, even if a battery cell generates heat and emits smoke, it is possible to prevent the thermal effects of the smoke on adjacent battery cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-74763 Summary of the Invention [Problem to be solved by the invention]

[0005] However, unlike the configuration of Patent Document 1, in a battery pack, a plurality of battery units each including three or more battery cells may be arranged in a row with a heat insulating material between them. In such a configuration, when one battery cell in one battery unit generates heat, the heat is more likely to be transferred to the battery cells adjacent to the battery cell in the battery unit than in a configuration without a heat insulating material. Therefore, there is a risk that all the battery cells included in the battery unit will generate heat. In that case, if a battery pack is configured so that the smoke exhaust path of each battery cell in one battery unit is shared, high-temperature gas from the plurality of battery cells will concentrate in the smoke exhaust path. As a result, there is a risk that the smoke exhaust path will be damaged.

[0006] The present disclosure provides a battery pack capable of preventing high-temperature gas discharged from multiple battery cells from concentrating in a single smoke exhaust path. [Means for solving the problem]

[0007] The battery pack of the present disclosure includes n battery units (n is a natural number of 2 or more) arranged in a predetermined direction, and a heat insulating material installed between the battery units. Each battery unit has a smoke exhaust valve, and includes m battery cells (m is a natural number of 3 or more) arranged adjacent to each other in a predetermined direction. The battery pack further includes m smoke exhaust ducts. Each smoke exhaust duct is attached to one battery cell in each battery unit, and exhausts gas exhausted from each smoke exhaust valve of the attached n battery cells to the outside of the battery pack.

[0008] According to the above disclosure, since a heat insulating material is provided between the battery units, if a thermal runaway occurs in any of the battery cells of a certain battery unit, the thermal runaway will only be transmitted to other battery cells within that battery unit, i.e., the thermal runaway will not be transmitted to battery cells of other battery units.

[0009] Furthermore, the gases generated in each battery cell of the battery unit are exhausted to the outside of the battery pack by each smoke exhaust duct without mixing with each other, so that it is possible to prevent gases from each battery cell in one battery unit from flowing into one of the multiple smoke exhaust ducts.

[0010] Therefore, the battery pack makes it possible to prevent high-temperature gas discharged from a plurality of battery cells from concentrating in a single smoke exhaust path. Effect of the Invention

[0011] According to the present disclosure, it is possible to prevent high-temperature gas discharged from multiple battery cells from concentrating in one smoke exhaust path. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic plan view of the battery pack. [Diagram 2] FIG. 1 is a diagram for explaining a state that may occur when one battery cell experiences thermal runaway. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0014] 1 is a schematic plan view of a battery pack 1 according to an embodiment. The battery pack 1 is mounted on a vehicle for use, for example. Examples of the vehicle include a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle (electric automobile), and a fuel cell vehicle.

[0015] As shown in FIG. 1, the battery pack 1 includes a plurality of battery units 10_1, 10_2, 10_3, etc. The plurality of battery units 10_1, 10_2, 10_3, etc. are arranged in a predetermined direction (the left-right direction in FIG. 1). Each of the battery units 10_1, 10_2, 10_3, etc. has three battery cells 101, 102, 103. The battery cells 101 to 103 are stacked in the predetermined direction. The battery cells 101 to 103 are prismatic batteries having a substantially rectangular shape in a plan view. The battery cells 101 to 103 are stacked in their thickness direction.

[0016] A stacking direction DR1 indicated by a double-headed arrow in Fig. 1 indicates the stacking direction of the battery cells 101 to 103. A perpendicular direction DR2 indicated by a double-headed arrow in Fig. 1 indicates a direction perpendicular to the stacking direction DR1 of the battery cells 101 to 103. The stacking direction DR1 is the same as the left-right direction in the figure (a predetermined direction).

[0017] In the following, for convenience of explanation, any one of the plurality of battery units 10_1, 10_2, 10_3, ... will also be referred to as "battery unit 10." Similarly, any one of the three battery cells 101-103 will also be referred to as "battery cell 100."

[0018] Each battery unit 10 has a pair of end plates (not shown) provided at both ends in the stacking direction DR1, and a restraining member (not shown) that restrains the multiple battery cells 100 in the stacking direction DR1. The multiple battery cells 100 are stacked with spacers (not shown) interposed therebetween.

[0019] Each of the multiple battery cells 100 includes a case. An electrode body and an electrolyte are accommodated inside the case. The electrode body includes positive and negative electrode sheets and a separator sandwiched between the electrode sheets. The electrode body may be of a laminated type or a wound type. Each of the multiple battery cells 100 includes a lid that closes an opening of the case. A positive electrode terminal and a negative electrode terminal are provided on the lid so as to protrude upward from the lid.

[0020] In each battery cell 100, the positive electrode terminal and the negative electrode terminal are arranged apart in the orthogonal direction DR2. In the battery unit 10, the positive electrode terminals and the negative electrode terminals are arranged alternately in the stacking direction DR1. Adjacent battery cells 100 in the stacking direction DR1 are electrically connected by a conductive bus bar (not shown). Each bus bar electrically connects the positive electrode terminal of one battery cell to the negative electrode terminal of the battery cell adjacent to that one battery cell. The bus bar has a flat plate shape. The multiple battery cells 100 included in the battery unit are electrically connected in series by the bus bar.

[0021] The battery cell 100 further has a smoke vent valve 151. The smoke vent valve 151 is provided on the lid of the battery cell 100. The smoke vent valve 151 is provided on the upper surface of the battery cell 100. The smoke vent valve 151 is formed, for example, by making a cut in the lid of the battery cell 100. The smoke vent valve 151 is disposed between the positive electrode terminal and the negative electrode terminal in the orthogonal direction DR2. The smoke vent valve 151 is disposed in the center of the battery cell 100 in the orthogonal direction DR2.

[0022] The smoke exhaust valve 151 opens when the pressure inside the battery cell 100 rises and exceeds a predetermined threshold value, for example, due to a short circuit occurring inside the case of the battery cell 100. Exhausting flammable gas inside the case through the smoke exhaust valve 151 prevents the internal pressure of the case from becoming excessive. Note that when the flammable gas cools, it turns into liquid or solid particles (i.e., smoke).

[0023] The battery pack 1 further includes a plurality of heat insulating materials 20. Each heat insulating material 20 is installed between the battery units 10. The heat insulating material 20 is installed between a battery cell 103 of one battery unit 10 and a battery cell 101 of the other battery unit 10 of adjacent battery units 10.

[0024] The battery pack 1 further includes three smoke exhaust ducts 31, 32, and 33. Each of the smoke exhaust ducts 31, 32, and 33 constitutes an independent smoke exhaust path. Each of the smoke exhaust ducts 31, 32, and 33 is installed above the battery cells 100. Each of the smoke exhaust ducts 31 to 33 is attached to one battery cell 100 in each battery unit 10, and exhausts gas exhausted from each smoke exhaust valve 151 of the attached battery cells 100 to the outside of the battery pack 1.

[0025] In this example, for the three battery units 10_1 to 10_3, the smoke exhaust duct 31 is attached to the battery cell 101 of the battery unit 10_1, the battery cell 103 of the battery unit 10_2, and the battery cell 101 of the battery unit 10_3. Similarly, the smoke exhaust duct 32 is attached to the battery cell 102 of the battery unit 10_1, the battery cell 102 of the battery unit 10_2, and the battery cell 102 of the battery unit 10_3. The smoke exhaust duct 33 is attached to the battery cell 103 of the battery unit 10_1, the battery cell 101 of the battery unit 10_2, and the battery cell 103 of the battery unit 10_3.

[0026] The smoke exhaust duct 31 has one main pipe section 31a and multiple branch pipe sections 31b. Similarly, the smoke exhaust duct 32 has one main pipe section 32a and multiple branch pipe sections 32b. The smoke exhaust duct 33 has one main pipe section 33a and multiple branch pipe sections 33b. Each branch pipe section 31b is connected to the main pipe section 31a. Similarly, each branch pipe section 32b is connected to the main pipe section 32a. Each branch pipe section 33b is connected to the main pipe section 33a.

[0027] The main pipes 31a, 32a, and 33a extend in a stacking direction DR1. The branch pipes 31b, 32b, and 33b extend in an orthogonal direction DR2 in a top view of the battery pack 1. The branch pipes 31b, 32b, and 33b extend in a direction (up-down direction) orthogonal to the stacking direction DR1 and the orthogonal direction DR2 in a side view of the battery pack 1.

[0028] Specifically, the branch pipes 31b, 32b, and 33b rise from the upper surface of the battery cell 100 and are bent 90 degrees midway. More specifically, the branch pipes 31b, 32b, and 33b surround the smoke vent valve 151 when the battery pack 1 is viewed from above.

[0029] In this example, the smoke exhaust duct 31 and the smoke exhaust duct 32 are installed at the same height. The smoke exhaust duct 33, except for the rising portion not shown, is located higher than the smoke exhaust ducts 31 and 32. By arranging in this manner, it is possible to prevent the three smoke exhaust ducts 31, 32, and 33 from interfering with each other.

[0030] As described above, in the battery pack 1, when focusing on one battery unit 10, the smoke exhaust paths of the three battery cells 100 included in the battery unit 10 are not shared but are independent of each other.

[0031] The number of battery units 10 included in the battery pack 1 may be two or more. The number of battery cells 100 included in one battery unit 10 may be three or more. If the number of battery units 10 is n (n is a natural number equal to or greater than 2) and the number of battery cells 100 included in one battery unit 10 is m (m is a natural number equal to or greater than 3), then it can be said that the battery pack 1 has the following configuration. The value of n and the value of m may be the same.

[0032] The battery pack 1 includes n battery units 10 arranged in a predetermined direction (stacking direction DR1) and thermal insulation materials 20 installed between the battery units 10. Each battery unit 10 has a smoke exhaust valve 151 and includes m battery cells arranged adjacent to each other in the predetermined direction. The battery pack 1 further includes m smoke exhaust ducts 31, 32, 33, etc. Each smoke exhaust duct 31, 32, 33, etc. is attached to one battery cell 100 in each battery unit 10, and exhausts smoke exhausted from each smoke exhaust valve 151 of the attached n battery cells 100 to the outside of the battery pack 1.

[0033] 2 is a diagram for explaining a state that may occur when one battery cell 100 experiences thermal runaway. As shown in FIG. 2, it is assumed that thermal runaway occurs in the battery cell 102 of the battery unit 10_2. In this case, heat is generated in the battery cell 102, and the heat is transferred to the battery cells 101 and 103 adjacent to the battery cell 102. As a result, a chain reaction of thermal runaway occurs in the battery cells 101 and 103 as well.

[0034] Incidentally, a heat insulating material 20 is installed between the battery cell 101 of the battery unit 10_2 and the battery cell 103 of the battery unit 10_1. Therefore, heat generated in the battery cell 101 of the battery unit 10_2 is not transferred to the battery cell 103 of the battery unit 10_1. Similarly, a heat insulating material 20 is installed between the battery cell 103 of the battery unit 10_2 and the battery cell 101 of the battery unit 10_3. Therefore, heat generated in the battery cell 103 of the battery unit 10_2 is not transferred to the battery cell 101 of the battery unit 10_3.

[0035] Therefore, if thermal runaway occurs in the battery cell 102 of the battery unit 10_2, the thermal runaway will only be chained to the other battery cells 101, 103 in the battery unit 10_2. In this way, the thermal runaway will not be chained to the battery cells 100 in the battery units 10 other than the battery unit 10_2. In other words, if thermal runaway occurs in a battery cell 100 of one battery unit 10, the chain of thermal runaway will be limited to the other battery cells 100 in the battery unit 10 that includes the battery cell 100 in which the thermal runaway occurred.

[0036] The gas 329 generated in the battery cell 102 of the battery unit 10_2 flows through the branch pipe section 32b of the smoke exhaust duct 32 via the smoke exhaust valve 151 of the battery cell 102 in a partially or entirely smoked state. The gas 329 then reaches the main pipe section 32a of the smoke exhaust duct 32. The gas 329 further flows through the main pipe 32a. Specifically, the gas 329 flows toward an exhaust port (not shown) of the main pipe section 32a. In this example, the gas 329 flows in the direction of the arrow 902 (stacking direction DR1). As a result, the gas 329 generated in the battery cell 102 is exhausted to the outside of the battery pack 1.

[0037] The gas 319 generated in the battery cell 101 of the battery unit 10_2 by the chain reaction described above flows through the branch pipe section 31b of the smoke exhaust duct 31 via the smoke exhaust valve 151 of the battery cell 101 in a partially or entirely smoked state. The gas 319 then reaches the main pipe section 31a of the smoke exhaust duct 31. The gas 319 further flows through the main pipe 31a. Specifically, the gas 319 flows toward an exhaust port (not shown) of the main pipe section 31a. In this example, the gas 319 flows in the direction of the arrow 901 (stacking direction DR1). As a result, the gas 319 generated in the battery cell 101 is discharged to the outside of the battery pack 1.

[0038] Similarly, the gas 339 generated in the battery cell 103 of the battery unit 10_2 by the above-mentioned chain reaction flows through the branch pipe section 33b of the smoke exhaust duct 33 via the smoke exhaust valve 151 of the battery cell 103 in a partially or entirely smoked state. The gas 339 then reaches the main pipe section 33a of the smoke exhaust duct 33. The gas 339 further flows through the main pipe 33a. Specifically, the gas 339 flows toward an exhaust port (not shown) of the main pipe section 33a. In this example, the gas 339 flows in the direction of the arrow 903 (stacking direction DR1). As a result, the gas 339 generated in the battery cell 103 is discharged to the outside of the battery pack 1.

[0039] In this way, in the battery pack 1, the gas 319 generated in the battery cell 101 of the battery unit 10_2, the gas 329 generated in the battery cell 102 of the battery unit 10_2, and the gas 339 generated in the battery cell 103 of the battery unit 10_2 are discharged to the outside of the battery pack 1 without mixing. Therefore, it is possible to prevent the gases 319, 329, and 339 from the three battery cells 101, 102, and 103 in one battery unit 10 from flowing into one of the three smoke exhaust ducts 31, 32, and 33.

[0040] In addition, when the battery cell 101 of the battery unit 10_2 experiences thermal runaway, the thermal runaway is first chained to the battery cell 102 of the battery unit 10_2. Next, due to the heat of the battery cell 102 of the battery unit 10_2, the thermal runaway is chained to the battery cell 103 of the battery unit 10_2. Similarly, when the battery cell 103 of the battery unit 10_2 experiences thermal runaway, the thermal runaway is first chained to the battery cell 102 of the battery unit 10_2. Next, due to the heat of the battery cell 102 of the battery unit 10_2, the thermal runaway is chained to the battery cell 101 of the battery unit 10_2.

[0041] In this way, even if battery cell 101 or battery cell 103 experiences thermal runaway, as in the case where battery cell 102 experiences thermal runaway, the gases generated in each battery cell 100 flow through the three smoke exhaust ducts 31 to 33 without mixing, as shown in FIG. 2.

[0042] In the above, the description has been focused on the battery unit 10_2. Even if thermal runaway occurs in any of the battery cells 100 of the other battery units 10, the gases generated in the battery cells 100 flow through the three smoke exhaust ducts 31-33 without mixing.

[0043] Therefore, the battery pack 1 can prevent high-temperature gas discharged from the multiple battery cells 100 from concentrating in one smoke exhaust path (smoke exhaust duct).

[0044] The connection relationship between the smoke exhaust ducts 31-33 and the battery cells 100 of each battery unit 10 is not limited to that shown in Figures 1 and 2. For example, the battery pack 1 may be configured so that the smoke exhaust duct 31 is connected to the battery cells 101 of each battery unit 10, and the smoke exhaust duct 33 is connected to the battery cells 103 of each battery unit 10.

[0045] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the scope of the claims, and it is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. [Explanation of symbols]

[0046] 1 battery pack, 10_1, 10_2, 10_3 battery unit, 20 heat insulation material, 31, 32, 33 smoke exhaust duct, 31a, 32a, 33a main pipe section, 31b, 32b, 33b branch pipe section, 101, 102, 103 battery cell, 151 smoke exhaust valve, 319, 329, 339 gas.

Claims

[Claim 1] A battery pack comprising: n battery units (n is a natural number of 2 or more) arranged in a predetermined direction; a heat insulating material provided between the battery units, Each of the battery units includes m battery cells (m being a natural number of 3 or more) that are adjacent to each other and aligned in the predetermined direction, The battery pack further includes the m smoke exhaust ducts, A battery pack, wherein each of the smoke exhaust ducts is attached to one of the battery cells in each of the battery units, and exhausts gas exhausted from each of the smoke exhaust valves of the attached n battery cells to the outside of the battery pack.

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