Wound Secondary Battery Case Welding for Stable Negative Conduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The contact state between the exposed part of the negative electrode current collector and the case body in secondary batteries is difficult to maintain due to the state of charge and deterioration over time, leading to unfavorable conduction.
Innovation Solution
A secondary battery design featuring a metallic case body with a sealing assembly and an electrode assembly where the negative electrode current collector's exposed part is welded to the case body, ensuring a stable conduction state through a stacked and welded structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposed part of the negative electrode current collector is simply contacted with the case body, then the structure is simple, but the conduction state cannot be maintained due to charge state changes and deterioration
Solution Approach 1:
The exposed part of the negative electrode current collector is welded to the case body in advance during manufacturing, establishing a secure conduction path before the battery enters service. This preliminary welding action ensures that subsequent changes in charge state or gradual deterioration cannot compromise the electrical connection, as the mechanical and electrical bond is already permanently established.
Solution Approach 2:
The patent replaces the simple mechanical contact system with a welding system. Instead of relying on friction-based or pressure-based mechanical contact between the current collector and case body, the invention uses welding to create a metallurgical bond, substituting a weak mechanical interaction with a strong permanent joint that maintains conduction reliability.
2Reliability
If the exposed part is welded to the case body, then conduction reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The welding operation is performed as a preliminary step during the battery assembly process, before final sealing and packaging. By executing the welding action early in the manufacturing sequence when components are still accessible and positioned, the process integrates smoothly into existing production workflows without requiring additional complex equipment or multi-step procedures.
3Reliability
If a negative electrode tab is used for conduction, then the conduction path is established, but local stress and vibration resistance are compromised
Solution Approach 1:
The patent extracts and eliminates the negative electrode tab component from the battery structure. By removing this separate tab element and directly welding the exposed current collector to the case body, the design simplifies the conduction path and eliminates the weak point where tabs typically create local stress concentrations and reduce vibration resistance. The current collector itself becomes both the structural and conductive element.
Solution Approach 2:
The invention merges the functions of the negative electrode tab and the current collector into a single integrated structure. Instead of having separate components (current collector + tab), the exposed portion of the current collector directly serves as the conduction interface with the case body, combining structural support and electrical conduction functions in one element, thereby improving vibration resistance and eliminating local stress points.
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
This design maintains a favorable conduction state between the negative electrode current collector and the case body, reducing the risk of performance deterioration and local stress, while eliminating the need for a negative electrode tab and improving vibration resistance.
Implementation Method 1
the stacked part is welded to the metallic case body
Data Source
AI summary
A secondary battery according to one embodiment of the present disclosure is characterized by comprising a metal case main body, and an electrode body that is accommodated in the case main body and formed by winding a positive electrode and negative electrode with a separator interposed therebetween, wherein: the negative electrode includes a negative electrode current collector, a negative electrode active material layer formed on the negative electrode current collector, and a negative electrode current collector exposed section where the negative electrode current collector is exposed; the negative electrode current collector exposed section is disposed on a winding ending section of the electrode body and makes more than one lap circling in the winding starting direction L from the winding ending section of the electrode body, thereby forming a laminated part comprising the negative electrode exposed section, the laminated part and the case main body being welded together.