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JP-2026075727-A - Battery cell manufacturing method

JP2026075727AJP 2026075727 AJP2026075727 AJP 2026075727AJP-2026075727-A

Abstract

[Problem] To provide a method for manufacturing a battery cell that includes an electrode body that can improve the heat dissipation around the welded portion of each electrode foil before joining a large number of stacked electrode foils and current collector terminals by laser welding, thereby suppressing phenomena such as perforation and necking on the outer circumference of the welded portion of the electrode foil. [Solution] A method for manufacturing a battery cell 10S including an electrode body 10 comprising an electrode foil 1 having an active material layer forming portion 11 and an active material layer non-forming portion 12, and a current collector terminal 2 joined to the active material layer non-forming portion of the electrode foil. The method comprises a first step S1 in which the electrode foils are brought into contact and fixed to each other at the active material layer non-forming portion to form a thermal resistance reduction portion RT of the electrode foil, in which the thermal resistance R1 at the contact fixing portion 121 between the electrode foils is reduced to the thermal resistance R2 at the separation portion 122 between the electrode foils, and a second step S2 in which the electrode foil and the current collector terminal are joined by laser welding such that the nugget boundary portion NK of the laser welding portion LY is connected to the thermal resistance reduction portion while the thermal resistance reduction portion and the current collector terminal are in contact. [Selection Diagram] Figure 1

Inventors

  • 鹿田 勝也

Assignees

  • プライムプラネットエナジー＆ソリューションズ株式会社

Dates

Publication Date
20260511
Application Date
20241023

Claims (7)

  1. A method for manufacturing a battery cell, comprising an electrode body having a plurality of electrode foils having an active material layer forming portion and an active material layer non-forming portion, and a current collector terminal joined to the active material layer non-forming portion of the electrode foil, A first step is to form a thermal resistance reduction portion of the electrode foil by contacting and fixing a plurality of electrode foils to each other in the portion where the active material layer is not formed, thereby reducing the thermal resistance in the contact and fixing portion between the portions where the active material layer is not formed to the thermal resistance in the separated portion where the portions where the active material layer is not formed to each other. A method for manufacturing a battery cell, comprising: a second step of laser welding the electrode foil and the current collector terminal together such that the nugget boundary of the laser-welded portion is connected to the thermal resistance reduction portion, while the electrode foil and the current collector terminal are in contact with each other.
  2. In the method for manufacturing a battery cell described in claim 1, In the first step, the portions of the electrode foils where the active material layer is not formed are divided into predetermined numbers and brought into contact and fixed to each other, and the thermal resistance reduction portions are formed at the contact and fixed portions between each divided portion where the active material layer is not formed. A method for manufacturing a battery cell, comprising the second step of bringing the thermal resistance reduction portions formed in the first step into contact with the current collection terminal in a stacked state, and joining the electrode foil and the current collection terminal by laser welding such that the nugget boundary portion of the laser-welded portion is connected to the thermal resistance reduction portion.
  3. In the method for manufacturing a battery cell described in claim 1, The thermal resistance reduction portion is formed intermittently or continuously around the nugget boundary portion, A method for manufacturing a battery cell, wherein the sum of the circumferential lengths of the connecting portion between the nugget boundary and the thermal resistance reduction portion is less than or equal to the outer circumference length of the nugget boundary and is formed to be at least half the length of the outer circumference.
  4. In the method for manufacturing a battery cell described in claim 1, A method for manufacturing a battery cell, wherein the thermal resistance reduction portion is formed intermittently or continuously along a direction that separates it from the active material layer forming portion.
  5. In the method for manufacturing a battery cell described in claim 1, A method for manufacturing a battery cell, wherein in the second step, the electrode foil is pressed against the current collector terminal by a cooling jig that contacts the thermal resistance reduction portion, and the electrode foil and the current collector terminal are laser-welded together.
  6. In a method for manufacturing a battery cell according to any one of claims 1 to 5, The thermal resistance reduction portion is formed by ultrasonic bonding of the non-active material layer portions, in a method for manufacturing a battery cell.
  7. In a method for manufacturing a battery cell according to any one of claims 1 to 5, The thermal resistance reduction portion is formed by pressure bonding the non-active material layer portions together, in a method for manufacturing a battery cell.

Description

This disclosed technology relates to a method for manufacturing battery cells used in hybrid vehicles, electric vehicles, and the like. Conventionally, in the manufacturing process for electrode bodies of battery cells used in hybrid vehicles and electric vehicles, when joining multiple stacked electrode foils to current collector terminals, methods such as ultrasonic bonding have been employed (see, for example, Patent Document 1). However, when using ultrasonic bonding to bond multiple electrode foils to current collector terminals in an overlapping manner, typically, the horn's protrusions are brought into contact with the thinner electrode foils, and the anvil is brought into contact with the thicker current collector terminals. The horn is then ultrasonically vibrated to bond the electrode foils together, simultaneously bonding the electrode foils to the current collector terminals. In this case, the ultrasonic vibrations from the horn are not easily transmitted to the joint between the electrode foils and the current collector terminals. Therefore, it is necessary to set the horn's pressure and vibration energy to a high level, which presents challenges such as cracking and foreign matter generation in the electrode foils due to vibration, as well as increased costs due to wear of the horn and anvil. Japanese Patent Publication No. 2015-217422 This is a partial schematic cross-sectional view of a battery cell formed by a battery cell manufacturing method according to one embodiment of the disclosed technology.This is a schematic cross-sectional view illustrating the heat dissipation state of welding in section A shown in Figure 1.Figure 2 is an enlarged schematic cross-sectional view of section C.This is a view taken along arrow B, as shown in Figure 1.This is a schematic cross-sectional view of a partial ultrasonic bonding apparatus used in the first step of manufacturing the electrode body of the battery cell shown in Figure 1, in which the thermal resistance reduction portion of the electrode foil is formed by ultrasonic bonding.This is a schematic cross-sectional view of a crimping device used in the first step of manufacturing the electrode body of the battery cell shown in Figure 1, in which the thermal resistance reduction portion of the electrode foil is formed by crimping.This is a schematic cross-sectional view of a welding apparatus used in the second step of manufacturing the electrode body of the battery cell shown in Figure 1, where the electrode foil and the current collector terminal are joined by laser welding.This is a view taken along arrow B in modified example 1 of the electrode body shown in Figure 1.This is a view from arrow B in modified example 2 of the electrode body shown in Figure 1.This is a view from arrow B in modified example 3 of the electrode body shown in Figure 1.This is a view taken along arrow B in modified example 4 of the electrode body shown in Figure 1.This is a view taken along arrow B in modified example 5 of the electrode body shown in Figure 1.This is a view from arrow B in modified electrode body 6 shown in Figure 1.This is a view from arrow B in modified electrode body 7 shown in Figure 1. <Overall description of this battery cell> Next, the overall configuration of the battery cell formed by the battery cell manufacturing method according to the embodiment of the disclosed technology (hereinafter also referred to as "this battery cell") will be described in detail with reference to the drawings (Figures 1 to 4). Figure 1 shows a partial schematic cross-sectional view of a battery cell formed by the battery cell manufacturing method according to one embodiment of the disclosed technology. Figure 2 shows a schematic cross-sectional view illustrating the heat dissipation state of welding in part A shown in Figure 1. Figure 3 shows an enlarged schematic cross-sectional view of part C shown in Figure 2. Figure 4 shows a view from arrow B shown in Figure 1. In each figure, the X direction indicates the longitudinal direction (axial direction) of the case body, the Y direction indicates the short direction of the case body, and the Z direction indicates the width direction of the long side portion of the case body. The Y direction is also the lamination direction of the electrode foil in the electrode body. As shown in Figures 1 to 4, the battery cell 10S is a battery cell 10 that includes an electrode body 10 comprising a plurality of electrode foils 1 having an active material layer forming portion 11 and an active material layer non-forming portion 12, and a current collector terminal 2 joined to the active material layer non-forming portion 12 of the electrode foil 1. The battery cell 10S is equipped with a battery case 3 that houses the electrode body 10. Here, the battery case 3 comprises a rectangular cylindrical case body 31 having rectangular openings 311 at both ends in the longitudinal direction (X direction), and a flat plate-shaped lid 32 that sea