JP-2026074625-A - Battery module

Abstract

[Challenge] To suppress the increase in the size of the battery module. [Solution] The present invention comprises a separator 20 having a plurality of battery cells 10 and a cooling gap G arranged between the battery cells, the separator containing expanded graphite. [Selection Diagram] Figure 1

Inventors

• 茂田 佑樹

Assignees

• 日産自動車株式会社

Dates

Publication Date

20260507

Application Date

20241021

Claims (5)

1. Multiple battery cells, The battery cells are separated by a separator that includes a cooling gap, The aforementioned separator contains expanded graphite, and is a battery module.
2. The battery cell includes a surface that is at least partially flat in the portion adjacent to the separator. The separator is composed of vertical wall portions parallel to the plane direction of the battery cell and horizontal wall portions connecting adjacent battery cells. The battery module according to claim 1, wherein the expanded graphite is included in the vertical wall portion.
3. The battery cell includes a surface that is at least partially flat in the portion adjacent to the separator. The separator is composed of vertical wall portions parallel to the plane direction of the battery cell and horizontal wall portions connecting adjacent battery cells. The battery module according to claim 1, wherein the expanded graphite is included in the side wall portion.
4. The aforementioned vertical wall portion is in contact with one of the adjacent battery cells, The aforementioned vertical wall portion is made of metal. The battery module according to claim 3, wherein thermal conductive grease is provided between the metal and the battery cell.
5. The battery module according to claim 4, wherein a heat insulating sheet is provided on the side surface of the battery cell where the separator is not provided.

Description

This invention relates to a battery module. Because individual battery cells have a small capacity, the desired battery performance is achieved by stacking multiple battery cells into a battery module. However, stacking battery cells in this way increases the energy density, which increases the likelihood of the battery cells becoming excessively hot. Conventional technologies concerning undesirable high-temperature conditions in battery modules disclose a sheet containing at least one of mineral powders and a flame retardant, which initiates an endothermic reaction at 100 to 1000°C, resulting in at least one structural change selected from the group consisting of phase change, expansion, foaming, and hardening, which prevents undesirable high-temperature conditions (see Patent Document 1). Japanese Patent Publication No. 2018-206605 This is a schematic diagram showing the internal structure of a battery module according to an embodiment, including the case, adjacent battery cells, and separators arranged between the battery cells.Figure 1 is a schematic diagram showing the state of the battery module at high temperatures.This is a schematic diagram showing a modified battery module of Figure 1, including the case, battery cells, and separator.This is a schematic diagram showing the normal state of a modified battery module according to Figure 1, including the case, battery cells, and separator.Figure 4 is a schematic diagram showing the state of the battery module at high temperatures.This is a schematic diagram showing a modified battery module according to Figure 1, including a case, battery cells, separators, and an insulating sheet. The embodiments of the present invention will be described below with reference to the attached drawings. In the drawings, identical components are denoted by the same reference numerals, and redundant descriptions are omitted. In the drawings, the size and proportions of each component are exaggerated to facilitate understanding of the embodiments and may differ from the actual size and proportions. Figure 1 is a schematic diagram showing the internal structure of a battery module 100 according to one embodiment of the present invention, illustrating the case 10, adjacent battery cells 20, and separators 30 arranged between the battery cells 20. An outline of one embodiment of the present invention, using Figure 1, is a battery module 100 comprising battery cells 20, separators 30 arranged between adjacent battery cells 20, and a case 10 housing the battery cells 20 and separators 30, etc. The battery module 100 according to this embodiment can be used, for example, as a power source for a vehicle (not shown) that is an electric vehicle driven by an electric motor. The vehicle is not limited to an electric vehicle; for example, the battery module 100 may be applied as a power source for a hybrid vehicle. The following describes each configuration in detail. (case) The battery module 100 is configured to house multiple battery cells 20 inside the case 10, and to house separators 30 between adjacent battery cells 20. In the battery module 100, components other than the case 10, battery cells 20, and separator 30 include busbars (not shown). Busbars are used to electrically connect the battery cells to each other. Case 10 can be made of a metal such as steel, for example. While the shape of case 10 can be a rectangular prism or similar, its specific shape is not particularly limited as long as it can accommodate the aforementioned components. (Battery cell) Multiple battery cells 20 are housed inside the case 10 and may include a positive electrode, a negative electrode, an internal separator, a positive electrode tab, a negative electrode tab, insulating material, etc. The size of the battery cell 20 is not particularly limited, but as an example, it can be configured to be 120-150 mm x 170-200 mm x 20 mm. The battery cell 20 can be formed to include at least a partially flat surface 21 in the area adjacent to the separator 30. Although the drawing shows the inside of the battery module 100, for convenience, the approximate shape of the battery cell 20 is shown in an uncut state. (Separator) The separator 30 is housed inside the case 10 and positioned between adjacent battery cells 20. It is configured to have a cooling gap G and to contain expanded graphite. This configuration ensures cooling performance under normal conditions through the role of the separator 30 in maintaining the gap G between the battery cells 20. Figure 2 is a schematic diagram showing the state of the battery module 100 at high temperatures. At high temperatures, the expandable graphite contained in the separator 30 expands, forming a porous or foam-like structure that creates an insulating layer, thus preventing heat transfer between the battery cells 20. Furthermore, by eliminating the need to place a separate insulating material between the battery cells 20, as in conventional designs, the gap G be