Jelly-Roll Electrode Assembly Layout for Low-Resistance Battery Tabs
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in minimizing electrode tabs to reduce resistance and prevent lithium precipitation during overcharging, which can lead to structural collapse and explosion.
Innovation Solution
The electrode assembly design includes non-coated portions on the positive and negative electrode plates, with strategically positioned tabs to minimize tab count and prevent lithium deposition, featuring a unique tab arrangement and non-coated areas to enhance safety and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of electrode tabs is increased to reduce internal resistance, then the resistance of the battery is lowered, but the space utilization of the internal space is reduced and the amount of material and man-hours increases
Solution Approach 1:
The patent combines multiple electrode tabs into a single integrated tab structure. The positive electrode tab and negative electrode tab are merged into one component that electrically connects both electrodes to the terminal, reducing the total number of tabs from multiple separate tabs to just one combined tab assembly.
Solution Approach 2:
The single electrode tab structure serves multiple functions simultaneously: it acts as the current collector for both positive and negative electrodes, provides the electrical terminal connection, and serves as the attachment point for the seal plate. This multi-functional design eliminates the need for separate tabs for each electrode.
2Power
If the length of the electrode plate is increased to achieve high capacity and high output, then the capacity and output are improved, but the internal resistance increases
Solution Approach 1:
The electrode plate is divided into multiple segments along its length, with each segment having its own local electrode tab connection point. This segmentation allows current to be collected at multiple locations along the electrode plate, reducing the current density and resistance in any single long section while maintaining the overall high capacity.
3Use of energy by moving object
If the positive electrode active material reacts excessively with the electrolyte during overcharging, then the energy density is increased, but the structural collapse of the positive electrode active material occurs and lithium precipitation happens
Solution Approach 1:
The patent applies a protective coating on the positive electrode active material surface before it comes into contact with the electrolyte during charging. This pre-applied protective layer prevents excessive oxidation reactions and structural collapse by blocking direct contact between the active material and electrolyte, while still allowing lithium ion insertion and extraction.
Data Source
AI summary
The present invention relates to an electrode assembly and a secondary battery including same. A jelly-roll-type electrode assembly comprises a positive electrode non-coated portion formed on a positive electrode plate, and a negative electrode non-coated portion formed on a negative electrode plate. The negative electrode non-coated portion includes a first negative electrode non-coated portion formed between the front end and the rear end of the negative electrode plate in the winding direction, and a second negative electrode non-coated portion formed at the rear end of the negative electrode plate. A negative electrode tab is disposed in the first negative electrode non-coated portion.