Battery Pack Terminal Design for Caulking Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
When assembling battery packs, the positive external terminals made of pure aluminum are prone to buckling due to their lower tensile strength, leading to loosening of the caulking state, especially when there are positional displacements during assembly, which can result in deformation and reduced sealing performance.
Innovation Solution
The battery pack design incorporates negative external terminals with a thinner plate thickness than positive external terminals, allowing them to absorb stress and prevent plastic deformation of the positive external extending parts, thereby maintaining the caulking state. This is achieved by using metals with varying tensile strengths for the positive and negative extending members and terminals, ensuring the negative external terminal has higher electrical conductivity and is more likely to deform, thus reducing stress on the positive external terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the positive external terminal is made of pure aluminum to maintain electrical conductivity, then electrical conductivity is improved, but tensile strength decreases causing buckling and loosening of caulking state
Solution Approach 1:
The invention uses composite material construction where the positive external terminal consists of an aluminum base material (for electrical conductivity) coated with an aluminum alloy surface layer (for enhanced tensile strength and buckling resistance). This composite structure combines the high conductivity of pure aluminum with the high strength of aluminum alloy, resolving the contradiction between electrical conductivity and mechanical strength.
Solution Approach 2:
The invention changes the material parameters of the positive external terminal by applying an aluminum alloy coating layer with specific composition and thickness parameters. This parameter modification enhances the tensile strength and buckling resistance while maintaining the underlying aluminum's electrical conductivity, thus resolving the strength-conductivity contradiction.
2Reliability
If fastening members are used to connect batteries in series, then electrical connection is achieved, but positional displacement causes deformation and loosening of the caulking state
Solution Approach 1:
The invention applies beforehand cushioning by designing the positive external terminal with enhanced buckling resistance through aluminum alloy coating. This pre-enhanced structural resilience cushions against the harmful effects of positional displacement during assembly, preventing deformation and loosening of the caulking state even when manufacturing precision is not perfect.
Solution Approach 2:
The invention implements preliminary anti-action by pre-strengthening the positive external terminal with an aluminum alloy coating layer that resists buckling. This preliminary strengthening counteracts the potential harmful deformation forces that arise from positional displacement during fastening, preventing the loosening of the caulking state before it can occur.
3Strength
If the positive external terminal is made thicker to prevent buckling, then tensile strength is improved, but the component becomes more prone to deformation during assembly
Solution Approach 1:
The invention uses composite material construction where the positive external terminal consists of an aluminum base material coated with an aluminum alloy surface layer. This composite structure provides enhanced buckling resistance through the high-strength alloy coating while maintaining appropriate thickness and flexibility to accommodate assembly tolerances without excessive deformation.
Solution Approach 2:
The invention applies local quality by concentrating the high-strength aluminum alloy material specifically at the surface layer and critical structural regions of the positive external terminal. This localized quality enhancement provides buckling resistance where needed while maintaining overall component flexibility and reducing unnecessary mass that could increase deformation susceptibility.
Data Source
AI summary
A battery pack has a plurality of series-connected batteries each having an electrode body, a battery case, a positive extending member, a positive external terminal mechanically joined and electrically connected to a positive external extending part of the positive extending member, by caulking deformation thereof, a negative extending member, and a negative external terminal mechanically joined and electrically connected to a negative external extending part of the negative extending member, by caulking deformation thereof. Among the positive and negative external extending parts, the positive and negative external terminals, the metal making up the positive external extending part has the lowest tensile strength. The battery pack includes bus bars; positive fastening members for fastening the positive external terminals to the bus bars; and negative fastening members for fastening the negative external terminals to the bus bars. The negative external terminal is thinner than the positive external terminal.