JP-7856520-B2 - Busbars and energy storage devices

Inventors

• 古嶋 佑帆
• 後藤 真之助
• 川崎 浩徳

Assignees

• イビデン株式会社

Dates

Publication Date

20260511

Application Date

20220729

Priority Date

20220519

Claims (10)

1. A busbar used in an energy storage device including a battery cell, The surface of the busbar body, which is made of a conductive material, is provided with an inorganic heat insulating material containing at least one of inorganic fibers and inorganic particles. A busbar characterized in that an inorganic fiber cloth is arranged on the side of the inorganic heat insulating material facing the battery cell.
2. The busbar according to claim 1 , characterized in that the laminate of the busbar body and the inorganic heat insulating material is wrapped with the inorganic fiber cloth.
3. A busbar used in an energy storage device including a battery cell, The surface of the busbar body, which is made of a conductive material, is provided with an inorganic heat insulating material containing at least one of inorganic fibers and inorganic particles. The inorganic thermal insulation material contains infusible fibers, The aforementioned infusible fiber is characterized by having a carbon content of 55 to 95% by mass.
4. A busbar used in an energy storage device including a battery cell, The surface of the busbar body, which is made of a conductive material, is provided with an inorganic heat insulating material containing at least one of inorganic fibers and inorganic particles. The inorganic thermal insulation material contains infusible fibers, The bus bar is characterized in that the infusible fibers consist of short fibers having a fiber length of 0.01 to 1000 mm .
5. A busbar used in an energy storage device including a battery cell, The surface of the busbar body, which is made of a conductive material, is provided with an inorganic heat insulating material containing at least one of inorganic fibers and inorganic particles. The inorganic thermal insulation material contains infusible fibers, The bus bar is characterized in that the infusible fiber has a fiber diameter of 1 to 30 μm.
6. A busbar used in an energy storage device including a battery cell, The surface of the busbar body, which is made of a conductive material, is provided with an inorganic heat insulating material containing at least one of inorganic fibers and inorganic particles. The aforementioned inorganic insulation material is characterized by containing organic fibers.
7. A busbar used in an energy storage device including a battery cell, The surface of the busbar body, which is made of a conductive material, is provided with an inorganic heat insulating material containing at least one of inorganic fibers and inorganic particles. The aforementioned inorganic thermal insulation material contains inorganic particles, The inorganic particles include first inorganic particles and second inorganic particles having different average particle diameters from each other. The busbar is characterized in that the first inorganic particles consist of at least one selected from oxide particles, carbide particles, nitride particles, and inorganic hydrate particles.
8. The bus bar according to claim 7 , characterized in that the first inorganic particle consists of at least one selected from nanoparticles, hollow particles, and porous particles.
9. The bus bar according to claim 7 , characterized in that the second inorganic particles are metal oxide particles.
10. A power storage device comprising multiple battery cells or battery modules connected by a busbar as described in any one of claims 1 to 9 .

Description

This invention relates to a busbar, a method for manufacturing the same, and an energy storage device in which multiple battery cells or battery modules are connected by a busbar. Various electronic devices, electric vehicles or hybrid vehicles driven by electric motors, and storage batteries are equipped with energy storage devices that connect multiple battery cells or battery modules in series or parallel using busbars. Furthermore, lithium-ion secondary batteries, which offer higher capacity and output compared to lead-acid batteries and nickel-metal hydride batteries, are primarily used as battery cells. However, during charging and discharging, if an overcurrent is passed through the battery cells or battery module, the busbars used for connection may overheat. Therefore, Patent Document 1 describes covering the busbars with a mica sheet. Japanese Patent Publication No. 2020-528650 Figure 1A is a perspective view showing an example of the busbar of the present invention.Figure 1B is a perspective view showing another example of the busbar of the present invention.Figure 2 is a cross-sectional view of Embodiment 1, taken along the line A-A in Figure 1A.Figure 3 is a cross-sectional view of Embodiment 2, taken along the line A-A in Figure 1A.Figure 4A is a cross-sectional view showing a power storage device equipped with the busbars shown in Figure 1A.Figure 4B is a cross-sectional view showing a power storage device equipped with the busbars shown in Figure 1B. The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, and can be modified and implemented as desired without departing from the spirit of the invention. [Overall configuration of the bus bar] Figure 1A is a perspective view showing an example of the busbar 1 of the present invention, showing it attached to a battery cell 110. As shown in the figure, the busbar body 5, made of a conductive material, is for example a metal plate member that is Z-shaped overall. The electrodes 111 of the battery cell 110 are inserted into the connection hole 6a at one end, and a terminal cap 112 is placed over it to secure it. The connection hole 6b at the other end of the busbar body 5 is connected to an adjacent battery cell (not shown) or an external device. The busbar 1 is then constructed by covering the part of the busbar body 5 excluding the connection holes 6a and 6b (the surface) with an inorganic heat insulating material 20, which will be described later. Furthermore, the busbar body 5 can be made entirely of an I-shaped flat plate, as shown in Figure 1B, and the portion excluding the connection holes 6a and 6b at both ends can be covered with inorganic insulation material 20 to form the busbar 1. Furthermore, the busbar 1 may be directly or indirectly connected to the electrodes 111 of the battery cell 110, or it may be electrically connected to the electrodes 111 of the battery cell 110. <Embodiment 1> Figure 2 is a cross-sectional view of the busbar 1 of Embodiment 1, taken along the line A-A in Figure 1A. The battery cell 110 is located on the lower side of the figure, and when the battery malfunctions, high temperatures and flames are generated from the battery cell 110. Therefore, an inorganic heat insulating material 20 is placed on the surface 5a of the busbar body 5 that faces the battery cell 110. Furthermore, in addition to the inorganic insulation material 20, an inorganic fiber sheet 30 may be laminated on the side facing the battery cell 110. The inorganic insulation material 20 and the inorganic fiber sheet 30 may or may not be bonded. If they are not bonded, an air layer is formed between the inorganic insulation material 20 and the inorganic fiber sheet 30, thereby improving the insulation performance. When a battery malfunctions, in addition to the high temperature emanating from the battery cell 110, gas from the electrolyte and fragments of the battery cell 110 are generated along with flames. Therefore, for the inorganic fiber sheet 30, an inorganic fiber cloth, specifically a woven fabric such as glass cloth, silica cloth, or alumina cloth, and especially a silica cloth (woven fabric), is preferred due to its excellent heat resistance and barrier properties against gas and fragments. Furthermore, an endothermic reaction layer 40 may be interposed between the surface 5a of the busbar body 5 and the inorganic insulation material 20. The endothermic reaction layer 40 has the effect of absorbing heat from the battery cell 110 that has experienced thermal runaway, thereby enhancing the insulation performance. Various resins can be used as the endothermic reaction layer 40, but a double-sided tape with adhesive layers formed on both sides of a resin base material is preferred because it can bond and fix the busbar body 5 and the inorganic insulation material 20 together. Furthermore, an insulating tape (ins