Lithium Battery Electrode Lead Structure for Low Internal Resistance
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Solution Overview
Problem
Conventional lithium secondary battery electrode assemblies face manufacturing difficulties due to complex cutting and trimming operations, limited lead arrangement, and increased internal resistance, which complicates the manufacturing process and reduces charge/discharge efficiency.
Innovation Solution
A conductive structure with large uncoated positive and negative lead areas and a mid-portion collecting area, utilizing a clasping assembly for direct electrical contact with the battery terminal, eliminating the need for welding and enhancing electrical contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cutting and trimming operations are used to prepare leads, then leads can be formed for electrical connection, but manufacturing complexity increases and waste bits are produced that may adhere to electrode surfaces causing conduction disturbance
Solution Approach 1:
The invention extracts and eliminates the cutting and trimming operations from the manufacturing process by designing leads with predetermined lengths during the layer formation stage. The leads are formed as integral parts of the electrode layers without requiring subsequent cutting or trimming, thus removing the source of waste bits that could adhere to electrode surfaces and cause conduction disturbances.
Solution Approach 2:
The leads are prepared in advance during the electrode layer formation process rather than being cut and trimmed afterward. The positive and negative electrode layers are formed with leads of predetermined lengths that extend beyond the winding, eliminating the need for subsequent cutting or trimming operations and preventing waste bit generation.
2Ease of manufacture
If leads are arranged in a concentric manner with equal lengths, then welding to conductive terminal is possible, but excessively long leads require tidying up operation that increases manufacturing complexity and risks breaking leads
Solution Approach 1:
The invention applies different lead length configurations to different layers based on their specific positions and requirements. Instead of requiring all leads to be of equal length, each layer's leads are formed with lengths appropriate to their location, with outer layers having longer leads and inner layers having shorter leads, eliminating the need for tidying up operations.
Solution Approach 2:
The lead lengths are made dynamic and adaptive to the layer position rather than static and uniform. The leads of different layers are designed with different lengths corresponding to their radial positions in the wound structure, allowing natural accommodation without requiring pressing or tidying operations.
3Reliability
If multiple leads are used to increase current transmission capacity, then internal resistance decreases and charge/discharge efficiency improves, but the welding area on conductive terminal becomes insufficient and manufacturing becomes more complicated
Solution Approach 1:
The invention merges multiple leads into a single integrated lead structure by forming the positive and negative electrode layers with leads that are naturally positioned and connected. The leads of different layers are combined into unified positive and negative terminal connections, eliminating the need for welding multiple separate leads to the conductive terminal while maintaining low internal resistance.
Solution Approach 2:
The electrode layers serve multiple functions: they provide both the active electrochemical material and the lead structure for electrical connection. The leads are formed as integral parts of the electrode layers during the coating and winding process, eliminating the need for separate lead fabrication and welding operations.
4Ease of manufacture
If direct electrical contact between electrode assembly and battery terminal is established without welding, then manufacturing process is simplified, but electrical contact area must be sufficiently large to maintain low internal resistance
Solution Approach 1:
The invention transitions from point-contact welding to surface-contact integration by forming the leads as extended surfaces of the electrode layers. The leads extend beyond the winding and make direct contact with the terminal over a distributed area rather than at discrete welded points, effectively increasing the electrical contact area through dimensional extension.
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
This design reduces internal resistance, improves charge/discharge efficiency, and simplifies the manufacturing process by allowing large current transmission without the need for multiple leads, thereby extending battery life and stability.
Implementation Method 1
The lead terminal is formed at its mid portion with a large collecting area. A clasping assembly enables the positive and negative lead areas to keep in electrical contact with the collecting area
Data Source
AI summary
An electrode assembly of a lithium secondary battery is specially designed such that the positive and negative layers are formed at a side thereof with a large uncoated negative lead area and a large uncoated positive lead area. In addition, the collecting area is located correspondingly to the negative lead area or the positive lead area. And then the clasping assemblies are fixed outside the positive lead area or the negative lead area. In this way, the two pressing pieces are firmly pressed against the positive lead area or the negative lead area. On the one hand, the respective layers of the positive lead area or the negative lead area are pressed closely against one another, and on the other hand, the innermost layer of the positive lead area or the negative lead area is allowed to be maintained in a tight electrical contact with the collecting area.