Electrode Assembly Stacking for Battery Expansion Alignment
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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 misalignment issues due to mechanical stresses, which affect reliability and cycle life.
Innovation Solution
A method for preparing electrode assemblies involving sheet alignment features to precisely stack negative electrode, separator, and positive electrode subunits, with weakened regions for controlled expansion and contraction, and centroid separation distances within predetermined limits to maintain alignment and prevent shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrodes are designed to accommodate ion insertion and extraction, then energy storage capacity is improved, but electrode expansion and contraction during cycling causes electrical shorts and battery failure
Solution Approach 1:
The electrode assembly is divided into multiple individual electrode subunits, each capable of independent expansion and contraction. These segmented subunits are arranged in a stack with separators between them, allowing each segment to accommodate volume changes during ion insertion/extraction without causing the entire electrode structure to deform, thereby preventing electrical shorts while maintaining high ion storage capacity.
2Ease of manufacture
If mechanical stresses are applied during manufacture, use or transport, then battery assembly is facilitated, but electrode misalignment occurs leading to shorting and failure
Solution Approach 1:
Separators are positioned between adjacent electrode subunits before assembly, creating a protective buffer layer that maintains precise alignment of electrodes during manufacturing, use, and transport. This pre-positioned separator network cushions against mechanical stresses and prevents electrode misalignment, ensuring reliable operation while facilitating assembly.
3Productivity
If electrode assembly structure is simplified, then manufacturing efficiency is improved, but control over electrode expansion and alignment is reduced
Solution Approach 1:
The electrode assembly is segmented into multiple independent subunits stacked with separators, creating a modular structure that is both simple to manufacture and precise in controlling electrode behavior. Each segment can be independently positioned and aligned, allowing for efficient assembly while maintaining high manufacturing precision through the repetitive, standardized stacking pattern.
Data Source
Figure 1A
Figure 1B
Figure 1C~1D
AI summary
Secondary batteries and methods of manufacture thereof are provided. A secondary battery can comprise an offset between electrode and counter-electrode layers in a unit cell. Secondary batteries can be prepared by 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.