Electrode Assembly Insulation Layout Against Lithium Dendrites
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Solution Overview
Problem
In secondary batteries, repeated charging and discharging can lead to positive ions depositing on the negative electrode, causing lithium dendrite formation and potentially puncturing the separator, resulting in short-circuits.
Innovation Solution
An electrode assembly design featuring a first and second electrode plate with uncoated portions, base tabs, and insulating tapes to prevent lithium deposition and protect the separator, including a tab cover tape and uncoated portion cover tape to minimize ion deposition and prevent short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode assembly uses a center tab configuration with uncoated portions, then the electrical connection and current collection are improved, but positive ions deposit on the uncoated portion causing lithium dendrite formation and separator puncture
Solution Approach 1:
An insulating tape is introduced as an intermediary component between the positive electrode and the uncoated portion of the negative electrode. This insulating tape prevents direct contact and blocks the path for positive ion deposition, thereby eliminating the harmful effect of lithium dendrite formation while preserving the electrical connection function through the base tabs
Solution Approach 2:
The electrode assembly is segmented into distinct functional zones: the uncoated portion for electrical connection, the coated portion for electrochemical reaction, and the insulating tape region for protection. This segmentation allows each zone to perform its specific function without interfering with others, preventing ion deposition while maintaining electrical connectivity
2Quantity of substance
If repeated charge and discharge cycles are performed, then the battery capacity and energy storage are improved, but positive ions permeate to the uncoated portion and stack to form lithium dendrites
Solution Approach 1:
The insulating tape is pre-installed on the positive electrode at the location corresponding to the uncoated portion before battery assembly. This preliminary protective measure is in place before any charge-discharge cycles begin, preventing positive ion deposition and lithium dendrite formation from the very first cycle, thus protecting separator integrity throughout the battery's service life
Data Source
AI summary
An electrode assembly includes: a first electrode plate having a first electrode uncoated portion spaced apart from both ends in a longitudinal direction thereof, and a base tab on one surface of the first electrode uncoated portion; a second electrode plate having a second electrode uncoated portion spaced apart from both ends in a longitudinal direction thereof, and a base tab on one surface of the second electrode uncoated portion; a separator between the first electrode plate and the second electrode plate; a tab cover tape attached to the one surfaces of the first electrode uncoated portion and the second electrode uncoated portion; an uncoated portion cover tape attached to each of the other surfaces of the first electrode uncoated portion and the second electrode uncoated portion; and an insulating tape attached onto the second electrode plate at a position corresponding to the first electrode uncoated portion.