Stacked Electrode Subunit Assembly for Battery Expansion Control
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Solution Overview
Problem
Rocking chair secondary batteries face challenges with electrode expansion and contraction during cycling, leading to electrical shorts and failure, as well as issues with electrode alignment and mechanical stability, which affect reliability and cycle life.
Innovation Solution
A method for manufacturing electrode assemblies involves removing subunits from sheets with weakened regions, stacking them with a separator layer to form unit cells, and using constraint systems to control expansion and maintain alignment, thereby reducing strain and improving mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrodes are designed to accommodate carrier ion insertion and extraction, then energy storage capacity is improved, but electrode expansion and contraction during cycling occurs leading to electrical shorts and battery failure
Solution Approach 1:
The electrode assembly is divided into multiple individual electrodes that are stacked together. This segmentation allows each electrode to be independently managed and positioned, reducing the overall expansion and contraction stress during cycling while maintaining energy storage capacity through the collective arrangement of multiple electrodes.
Solution Approach 2:
A constraint system is introduced as an intermediary component between the electrodes and the battery housing. This constraint system mechanically restrains the electrodes, preventing excessive expansion and contraction during charge-discharge cycles, thereby maintaining electrode alignment and preventing electrical shorts while allowing the electrodes to perform their energy storage function.
2Quantity of substance
If electrode assembly is designed to accommodate expansion, then energy storage capacity is improved, but mechanical stability and electrode alignment deteriorate
Solution Approach 1:
The constraint system is designed with dynamic characteristics that allow it to adapt to the expansion and contraction of electrodes during cycling. The constraints provide mechanical restraint while accommodating the dynamic volume changes, maintaining electrode alignment throughout the charge-discharge cycles without compromising energy storage capacity.
3Reliability
If constraint systems are added to control electrode expansion, then reliability is improved, but device complexity increases
Solution Approach 1:
The constraint system is designed to perform multiple functions simultaneously: it restrains electrode expansion, maintains electrode alignment, and provides structural support for the stacked electrode assembly. This multi-functionality reduces the need for separate components and simplifies the overall assembly process while improving reliability.
Data Source
AI summary
Embodiments of a method for the preparation of an electrode assembly, include removing a population of negative electrode subunits from a negative electrode sheet, the negative electrode sheet comprising a negative electrode sheet edge margin and at least one negative electrode sheet weakened region that is internal to the negative electrode sheet edge margin, removing a population of separator layer subunits from a separator sheet, and removing a population of positive electrode subunits from a positive electrode sheet, the positive electrode sheet comprising a positive electrode edge margin and at least one positive electrode sheet weakened region that is internal to the positive electrode sheet edge margin, and stacking members of the negative electrode subunit population, the separator layer subunit population and the positive electrode subunit population in a stacking direction to form a stacked population of unit cells.