Large-Capacity Unit Cell With Core-Free Wound Electrode Modules
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Solution Overview
Problem
The capacity of cylindrical batteries with wound-type electrode groups is limited due to the tight winding causing friction and dislocation of electrode sheets, leading to potential short circuits and security hazards.
Innovation Solution
A large-capacity unit cell design where the electrode sheets and separator are wound around a central shaft without being pulled, allowing for increased winding radius and uniformity, and the electrode groups are connected in parallel or series with improved heat dissipation and safety features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the winding radius of the electrode group is increased to achieve larger battery capacity, then the capacity of the unit cell is improved, but the friction between the electrode group and winding core increases causing electrode sheets to dislocate and separator to be damaged
Solution Approach 1:
The patent removes the winding core from the final battery structure, extracting the problematic component that causes friction and damage. The electrode group is designed to be freely movable during assembly, allowing the winding core to be completely removed after winding, thereby eliminating the source of friction and dislocation issues that limit capacity expansion.
Solution Approach 2:
The patent performs preliminary positioning of the electrode group using the winding core during the winding process, then removes the core. This preliminary action allows for controlled winding at larger radii without the core present in the final structure, preventing the core from causing friction and damage during battery operation.
2Reliability
If the winding radius is kept small to maintain electrode group stability, then the reliability is improved, but the length of electrode sheets is limited reducing battery capacity
Solution Approach 1:
By removing the winding core after the winding process, the patent eliminates the constraint that forces small winding radii. The electrode group can be wound at larger radii during manufacturing, and the removed core no longer causes friction or stability issues, allowing both large capacity and reliability to be achieved.
3Ease of manufacture
If the electrode group is pulled from the winding core during production, then the assembly process is completed, but the friction and force applied cause electrode sheets to dislocate and separator to be damaged
Solution Approach 1:
The patent extracts the winding core after winding to complete the assembly process without requiring forceful removal of the electrode group. The core serves only its winding function and is then removed, allowing the electrode group to be released without friction or damage to the delicate electrode sheets and separator.
Solution Approach 2:
The winding core performs its preliminary function of enabling the winding process, then is removed to allow free movement of the electrode group during assembly. This preliminary action completes the manufacturing process without compromising electrode sheet positioning or separator integrity.
Data Source
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AI summary
The present invention provides a large-capacity unit cell, and relates to the field of battery technologies. The large-capacity unit cell provided in the present invention comprises a base body provided with a plurality of accommodation cavities, each of the accommodation cavities being provided with an electrode group module, wherein the electrode group modules are connected to each other; and the electrode group module comprises a central shaft and an electrode group wound around the central shaft, the electrode group comprises a positive electrode sheet, a negative electrode sheet and a separator, and the separator is used to separate the positive electrode sheet from the negative electrode sheet. In the large-capacity unit cell, the capacity of the unit cell is effectively increased by winding an electrode sheet around a central shaft and connecting a plurality of electrode group modules in parallel.