Electrode Tab Welding with Pre-Bending to Prevent Disconnection
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Solution Overview
Problem
Secondary batteries face a risk of electrode tab disconnection due to reduced length from the electrode assembly to the welding point, especially in high-capacity and high-performance pouch-type batteries, which can lead to potential fires.
Innovation Solution
An apparatus and method that includes a guide part to gather electrode tabs on a predetermined area, a welding part to weld them, and a bending part to increase the length from the electrode assembly to the welding point, using a support and pressing mechanism to prevent disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the peripheral portion length is reduced to increase energy density, then the energy density is improved, but the electrode tab length from electrode assembly to welding point is reduced, increasing disconnection risk
Solution Approach 1:
The electrode assembly is bent in advance during the welding process to pre-lengthen the electrode tab path before welding occurs. This preliminary action ensures that even with reduced peripheral portion length, the electrode tab maintains sufficient length to prevent disconnection under subsequent mechanical stress.
Solution Approach 2:
The electrode assembly is dynamically bent during the welding process rather than maintaining a fixed position. This dynamic adjustment allows the electrode tab length to be optimized in real-time, ensuring adequate length for reliable connection while accommodating the reduced peripheral portion design.
2Reliability
If the electrode tab length from electrode assembly to welding point is increased, then the disconnection risk is reduced, but the peripheral portion length must be increased, reducing energy density
Solution Approach 1:
The bending action is performed preliminarily during the welding process itself, allowing the electrode tab to achieve the necessary effective length without requiring additional peripheral portion length. This resolves the contradiction by achieving reliability enhancement within the constrained space.
Solution Approach 2:
The spatial configuration of the electrode assembly is changed by bending it during welding, which effectively increases the electrode tab path length without increasing the linear dimensions of the peripheral portion. This parameter change in spatial arrangement allows both reliability and energy density requirements to be met.
3Reliability
If the electrode assembly is bent during welding, then the electrode tab length is increased to prevent disconnection, but the welding process complexity is increased
Solution Approach 1:
The bending function and welding function are merged into a single integrated welding device. The bending part and welding part work together in one coordinated operation, eliminating the need for separate bending and welding steps. This merging reduces overall process complexity while achieving the reliability benefit.
Solution Approach 2:
The welding device is designed with multi-functionality, incorporating both bending capability and welding capability in a single apparatus. This universal device performs multiple functions (bending and welding) simultaneously or sequentially, avoiding the need for multiple separate devices and reducing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents electrode tab disconnection by increasing the length from the electrode assembly to the welding point, ensuring stability even under deformation or expansion of the battery pouch.
Implementation Method 1
a bending part configured to bend the electrode assembly so that a length from the electrode assembly to the gathering area increases in at least a portion of the electrode tabs
Implementation Method 2
a welding part configured to weld the electrode tabs gathered by the guide part
Data Source
AI summary
An apparatus and method for welding electrode tabs protruding from an electrode assembly to each other which may include a guide part configured to gather the electrode tabs on a predetermined gathering area, a welding part configured to weld the electrode tabs gathered by the guide part, and a bending part configured to bend the electrode assembly. The bending part ensures that a length from the electrode assembly to the gathering area increases in at least a portion of the electrode tabs before being welded by the welding part. Accordingly, some aspects of the present invention may prevent the electrode tabs from disconnecting. Moreover, the present invention also relates to a secondary battery and may relate to a secondary battery manufactured by the above-described welding apparatus or method.