Laminated Lithium Metal Battery Tab Layout for Stress Relief
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Solution Overview
Problem
Lithium metal or lithium-containing alloy batteries experience expansion and contraction during charging and discharging, leading to stress on connection portions between electrodes and bus bars, which can result in performance and reliability deterioration.
Innovation Solution
A secondary battery design where positive and negative electrode tabs are positioned on opposite sides across the center line in the thickness direction of the battery cell, allowing them to face each other and connect via a bus bar, thereby reducing stress on the connection points during expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal or lithium-containing alloy is used as negative electrode active material, then high energy density is achieved, but the battery cell expands and contracts during charging and discharging causing stress on connection portions
Solution Approach 1:
The patent positions the positive electrode tab and negative electrode tab asymmetrically on opposite sides of the center line in the thickness direction of the battery cell. This asymmetric arrangement allows the tabs to face each other between adjacent battery cells, creating a configuration where the connection portions are optimally positioned to minimize stress during expansion and contraction while maintaining high energy density with lithium metal or lithium-containing alloy negative electrodes
2Productivity
If battery cells are laminated and connected using bus bars, then assembly efficiency is improved, but stress concentration occurs at connection portions during battery cell expansion and contraction
Solution Approach 1:
The patent positions the positive and negative electrode tabs in the thickness direction of the battery cell (vertical dimension) rather than only in the planar direction. By placing tabs on opposite sides of the center line in the thickness direction, the connection portions between adjacent laminated battery cells are optimized to reduce stress concentration while maintaining efficient assembly through bus bar connections
Data Source
AI summary
A secondary battery is configured by stacking a plurality of battery cells containing a lithium metal or a lithium-containing alloy as a negative electrode active material on a negative electrode layer. The battery cell has a positive electrode tab connected to the positive electrode collector and exposed to the outside, and a negative electrode tab connected to the negative electrode current collector and exposed to the outside. The positive electrode tab and the negative electrode tab are provided on opposite sides of the center line in the thickness direction of the battery cell, and the positive electrode tab and the negative electrode tab of the adjacent battery cells are arranged and connected so as to face each other.