Electrode Assembly Layout for Lower-Resistance Jelly-Roll Batteries
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Solution Overview
Problem
Existing electrode assemblies in secondary batteries face challenges with high resistance and capacity loss, particularly in jelly-roll type assemblies, which affect their performance and efficiency.
Innovation Solution
The electrode assembly design includes non-coating portions on the positive and negative electrode sheets, with strategically positioned tabs and insulation tapes to minimize resistance and capacity loss, featuring a configuration where the first positive electrode non-coating portion corresponds to the first negative electrode non-coating portion, and additional negative electrode tabs are used to enhance conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electrode assembly design with uniform coating is used, then the manufacturing process is simple, but the resistance is high and capacity loss occurs
Solution Approach 1:
The electrode sheets are divided into multiple non-coating portions (first, second, third negative electrode non-coating portions and first, second positive electrode non-coating portions) where tabs are strategically positioned. This segmentation allows current to be collected at multiple points along the electrode length, reducing overall resistance without requiring complete coating of the electrode surface.
Solution Approach 2:
Different regions of the electrode sheets have different properties: coated regions provide active material for capacity, while non-coating portions provide low-resistance current collection paths. The non-coating portions are specifically positioned to create optimal current flow paths to the tabs, creating local quality variations that reduce overall resistance.
2Reliability
If tabs are positioned without corresponding non-coating portions, then the electrode structure is simpler, but capacity loss increases due to uneven winding
Solution Approach 1:
Non-coating portions are pre-positioned at specific locations on the electrode sheets before assembly, with the first negative electrode non-coating portion positioned to correspond with the first positive electrode non-coating portion. This preliminary positioning ensures that when tabs are attached and winding occurs, the electrodes align properly, preventing capacity loss from uneven winding.
3Reliability
If multiple non-coating portions and tabs are added to reduce resistance, then resistance decreases, but the device complexity increases
Solution Approach 1:
The non-coating portions serve multiple functions simultaneously: they provide low-resistance current collection paths, serve as attachment points for tabs, enable proper electrode alignment during winding, and prevent capacity loss. This multi-functionality reduces the need for additional separate components, managing complexity while achieving resistance reduction.
Data Source
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AI summary
An electrode assembly according to the present invention comprises a positive electrode sheet comprising a positive electrode active material portion that is an area on which a positive electrode active material is stacked on a positive electrode collector and a positive electrode non-coating portion that is an area on which the positive electrode active material is not stacked, a positive electrode tab disposed on the positive electrode non-coating portion, a negative electrode sheet comprising a negative electrode active material portion that is an area on which a negative electrode active material is stacked on a negative electrode collector and a negative electrode non-coating portion that is an area on which the negative electrode active material is not stacked; a negative electrode tab disposed on the negative electrode non-coating portion, and a separator configured to insulate the positive electrode sheet and the negative electrode sheet from each other, wherein the positive electrode non-coating portion comprises a first positive electrode non-coating portion and a second positive electrode non-coating portion, which are provided on two portions spaced apart from each other on the positive electrode sheet.