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EP-4496074-B1 - BATTERY PACK

EP4496074B1EP 4496074 B1EP4496074 B1EP 4496074B1EP-4496074-B1

Inventors

  • SHIMIZU, KEISUKE

Dates

Publication Date
20260506
Application Date
20230313

Claims (5)

  1. A battery pack (10) comprising: a plurality of battery blocks (30) each including a gas exhaust surface (30a), the gas exhaust surfaces (30a) of the plurality of battery blocks (30) facing each other; and a heat-resistant member (36) arranged between the gas exhaust surfaces (30a) facing each other, and defining gas exhaust paths (37) between the heat-resistant member (36) and each of the gas exhaust surfaces (30a) facing each other; wherein each of the plurality of battery blocks (30) includes: a plurality of cells (31) each including a gas exhaust valve (31c), and a holder (32) holding the plurality of cells (31) and aligning the gas exhaust valves (31c) of the plurality of cells (31) on a holder end surface (32e) of the holder (32) to define the gas exhaust surfaces (30a), and the heat-resistant member (36) is fixed between the holder end surfaces (32e) of the plurality of battery blocks (30), the holder end surfaces (32e) facing each other, and displaceable to widen a corresponding one of the gas exhaust paths (37) in response to a pressure of gas exhausted from an abnormal cell (31) among the plurality of battery cells (31), characterized in that the holder (32) includes a protruding part (32g) protruding from the holder end surface (32e), and one of claw parts (32i), the claw parts (32i) of the plurality of battery blocks (30) sandwiching and fixing the heat-resistant member (36) when the protruding parts (32g) facing each other of the holder end surfaces (32e) are brought into contact with each other, and in that the heat-resistant member (36) includes a hole (36b) through which the protruding part (32g) is allowed to pass, and is displaceable by breaking the claw part (32i) in response to a pressure of gas exhausted from the abnormal cell (31).
  2. The battery pack (10) according to claim 1, wherein the heat-resistant member (36) is fixed with a plurality of sections sandwiched between side surfaces of the holder end surfaces (32e) facing each other, and the heat-resistant member (36) includes the deformable part (36a) deformable in response to a pressure of gas exhausted by the abnormal cell (31).
  3. The battery pack (10) according to claim 2, wherein the heat-resistant member (36) includes a metal hard plate (39), and a protective sheet (38) covering both surfaces of the metal hard plate (39), and the protective sheet (38) functions-as-the deformable part (36a).
  4. The battery pack (10) according to claim 1, wherein the heat-resistant member (36) includes an elastic material and shows a curved shape that is brought into contact with and is fixed to the holder end surface (32e), and is deformable in a part that is brought into contact with the holder end surface (32e) and is displaceable to widen the gas exhaust path (37) in response to a pressure of gas exhausted from the abnormal cell (31).
  5. The battery pack (10) according to claim 1, wherein the heat-resistant member (36) includes an elastic part including an elastic material, and a plate-shaped part that is pressed to the holder end surface (32e) by the elastic part, and, is displaceable to widen the gas exhaust path (37) by displacing the plate-shaped part in response to a pressure of gas exhausted by the abnormal cell (31) that faces the plate-shaped part.

Description

Technical Field The present disclosure relates to a battery pack. Background Art A nonaqueous electrolyte secondary battery such as a lithium-ion battery is used in the form of a battery pack in which a plurality of cells (batteries) is electrically connected and housed in a case. If there is an abnormality in the cells in the battery pack and one cell is abnormal and undergoes thermal runaway, a chain of thermal runaways may occur successively when a high-temperature gas is discharged from the cell and brought into contact with the surrounding cells. In a battery pack in which gas exhaust valves face each other, since the space between the facing cells is narrow, the battery pack is susceptible to thermal runaway cells. This problem is particularly remarkable in ultra-narrow battery packs with increased energy density. In order to prevent a chain reaction of thermal runaways caused by high-temperature gas, it is necessary to prevent contact with high-temperature gas generated from abnormal cells. Patent Literature 1 describes a power supply device (battery pack) in which a heat-resistant sheet is arranged in the center between gas exhaust valves of cells arranged to face each other, and exhaust chambers (gas exhaust paths) are provided on both sides of the heat-resistant sheet. Citation List Patent Literature PTL 1: PCT International Publication No. WO2019/065169 SUMMARY OF THE INVENTION In the structure of the battery pack of Patent Literature 1, a gas exhaust path is formed between gas exhaust valves of both cells facing each other and a heat-resistant sheet. Therefore, it is necessary to provide a sufficient distance between the gas exhaust valves of the cells facing each other, resulting in increasing the size of the battery pack and decreasing energy density. The disclosure of document EP 4 318 770 A1 is also relevant to understanding the invention. An object of the present disclosure is to provide a battery pack that can be miniaturized and can suppress a chain reaction of thermal runaways to the cells facing each other, even when a cell undergoes a thermal runaway. A battery pack according to the present invention is defined by the appended claims. A battery pack according to the present disclosure can be miniaturized, and can suppress a chain reaction of thermal runaways to another cell which the one cell faces even if one cell undergoes thermal runaway. [Brief Description of Drawings] FIG. 1 is an external view of a battery pack according to the present disclosure.FIG. 2 is an external view of a battery block according to the present disclosure.FIG. 3 is an exploded view of the battery block of FIG. 2.FIG. 4 is a sectional view illustrating a gas exhaust structure of the battery pack that does not fall within the scope of the present invention.FIG. 5 is a view illustrating a mechanism in which a gas exhaust path of the battery pack of FIG. 4 is widened.FIG. 6 is an example of a structure of a heat-resistant member of the present disclosure.FIG. 7 is a sectional view illustrating a second gas exhaust structure of the battery pack according to the present invention.FIG. 8 is a sectional view illustrating a third gas exhaust structure of the battery pack that does not fall within the scope of the present invention.FIG. 9 is a sectional view illustrating a fourth gas exhaust structure of the battery pack that does not fall within the scope of the present invention. [Description of Embodiments] Hereinafter, the exemplary embodiment of the present disclosure is described with reference to drawings. The shapes, materials, directions, and numerical values described below are examples, and can be appropriately modified according to applications of use, purposes, and specifications. Furthermore, component elements of the exemplary embodiments, modifications, and the like, mentioned below are expected to be selectively combined from the beginning. <First exemplary embodiment> FIG. 1 is an external view of battery pack 10 according to the present disclosure. Battery pack 10 includes outer covering case 20 made of metal such as aluminum, and a plurality of battery blocks 30 housed inside outer covering case 20, and heat-resistant member 36 arranged between the plurality of battery blocks 30. Note here that outer covering case 20 is not limited to be made of metal and may be made of resin. Battery block 30 includes a plurality of cells 31 arranged in line, and the plurality of cells 31 is electrically connected to each other. In battery block 30, a plurality of cells 31 is, for example, electrically connected in parallel. Battery pack 10 includes a plurality of battery blocks 30 electrically connected in series or in parallel to output a voltage suitable for respective devices to be used. Cell 31 is, for example, a cylindrical battery. Note here that in this disclosure, a cylindrical battery is described as an example of cell 31, but a battery is not limited to a cylindrical battery, and may be a prismatic batt