Electrode Assembly Resistance Balancing for Longer Battery Cycle Life
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Solution Overview
Problem
Secondary batteries face challenges in maintaining a longer cycle life due to structural changes, electrolyte decomposition, and the consumption of active ions during charging and discharging, leading to capacity attenuation.
Innovation Solution
An electrode assembly design with a positive electrode plate and a negative electrode plate, where the first and second film layers on each plate have specific capacity and resistance ratios, optimizing the distribution of active ions and voltage response to prolong cycle life by pre-storing ions for gradual release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If secondary batteries are used for charging and discharging, then energy storage and power supply functions are achieved, but active ions are consumed due to structural changes, electrolyte decomposition, and SEI film formation, leading to capacity attenuation and reduced cycle life
Solution Approach 1:
The patent applies preliminary action by pre-storing active ions in the electrode assembly before the battery begins cycling. The electrode structure is designed with excess active ions that are held in reserve and gradually released during charge-discharge cycles to compensate for the ions consumed by SEI film formation and electrolyte decomposition, thereby extending cycle life without requiring more frequent top-up operations
2Speed
If the electrode assembly is designed with specific resistance ratios to improve voltage response speed, then charging efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by establishing specific mathematical relationships between the resistances of different electrode film layers (R1, R2, R3, R4) to optimize voltage response speed. By defining precise resistance ratios that must be satisfied during manufacturing, the patent transforms the complex multi-parameter electrode design into controllable parameter relationships that can be systematically managed during production while achieving improved charging performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The optimized electrode assembly significantly extends the cycle life of secondary batteries by ensuring sufficient pre-stored active ions are released to compensate for consumption, thereby delaying capacity decay and improving energy density.
Implementation Method 1
During the charging and discharging process of secondary batteries, active ions (such as lithium ions) are intercalated and deintercalated between a positive electrode and a negative electrode
Implementation Method 2
active ions (such as lithium ions) are intercalated and deintercalated between a positive electrode and a negative electrode
Implementation Method 3
a separator disposed between the positive electrode plate and the negative electrode plate
Data Source
AI summary
An electrode assembly, secondary battery, battery module, battery pack and electrical device are provided. In some embodiments, the electrode assembly comprises a positive electrode plate, a negative electrode plate and a separator disposed between the positive electrode plate and the negative electrode plate, the positive electrode plate satisfies CAP1=CAP2, in which CAP1 represents capacity of the first positive electrode film layer in Ah, CAP2 represents capacity of the second positive electrode film layer in Ah, and the electrode assembly satisfies |R4/R3−R2/R1|>0, in which R1 represents resistance of the first positive electrode film layer in Ω, R2 represents resistance of the second positive electrode film layer in Ω, R3 represents resistance of the first negative electrode film layer in mΩ and R4 represents resistance of the second negative film layer in mΩ. The present applicant may extend the cycle life of the secondary battery.