Tab-Less Cylindrical Battery Structure for Low-Resistance Current Collection
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Solution Overview
Problem
Conventional cylindrical batteries face issues with current collection efficiency due to high resistance and heat generation, especially during rapid charging, which can lead to thermal runaway and reduced energy density, particularly when scaled for electric vehicles.
Innovation Solution
The design features a tab-less cylindrical battery with uncoated regions of the electrodes positioned at the top and bottom, allowing for improved current collection through larger cross-sectional areas and optimized terminal structures to minimize resistance and maximize energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cylindrical battery structure with strip-shaped electrode tabs is used, then manufacturing is simple, but current collection efficiency is poor due to high resistance and heat generation
Solution Approach 1:
The invention divides the single electrode tab into multiple electrode tabs along the width direction of the electrode. This segmentation increases the current collection area and distributes current flow across multiple paths, reducing resistance and heat generation while maintaining manufacturing simplicity through a straightforward extension of conventional tab-attachment processes
Solution Approach 2:
The invention extends the current collection area from a one-dimensional strip-shaped tab to a two-dimensional multi-tab structure by arranging multiple tabs along the width direction. This dimensional expansion significantly increases the effective current collection area without complicating the basic manufacturing process
2Reliability
If electrode tab area is increased to improve current collection, then resistance decreases, but heat generation increases during rapid charging
Solution Approach 1:
By segmenting the electrode into multiple tabs, the current is distributed across multiple parallel paths rather than concentrating through a single large tab. This reduces the current density in each individual tab, thereby reducing Joule heating (I²R losses) while maintaining low overall resistance through the parallel configuration
Solution Approach 2:
The invention optimizes the local properties of each electrode tab by positioning multiple tabs at different locations along the electrode width. This creates multiple localized current collection points that distribute heat generation across different regions, preventing hot spot formation while maintaining efficient current collection
3Quantity of substance
If battery can size is increased for electric vehicle applications, then energy density increases, but thermal runaway risk increases due to heat generation
Solution Approach 1:
The multi-tab configuration segments the current collection paths within the larger battery can, distributing current flow and heat generation across multiple locations. This prevents concentrated thermal stress that could lead to thermal runaway, while the overall larger battery can provides higher energy density for electric vehicle applications
Solution Approach 2:
The invention converts the potential harm of heat generation in large-capacity batteries into a benefit by distributing it across multiple tabs. The heat that would otherwise concentrate in a single location is now dispersed, and this distributed heat management becomes an advantage for thermal safety while maintaining the high energy density needed for electric vehicles
4Power
If multiple batteries are connected in series to increase output voltage, then voltage increases, but device complexity increases
Solution Approach 1:
The standardized multi-tab electrode structure creates a universal battery design that simplifies battery pack assembly. Multiple batteries can be connected in series with consistent terminal configurations, reducing the complexity of wiring and assembly compared to customized connections, while achieving the required output voltage for various applications
Data Source
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AI summary
A battery comprises a rolled electrode assembly having a first electrode and a second electrode and a separator interposed therebetween, the first electrode having a first uncoated region and the second electrode having a second uncoated region, the first and second uncoated regions being not coated with an active material, disposed at a long side end of the first electrode and second electrode, respectively, and exposed out of the separator; a battery can accommodating the electrode assembly and electrically connected to the second uncoated region, wherein the battery can comprises a first end face, a second end face and a cylindrical sidewall extending between the first end face and the second end face, wherein the second end face has an opening; a terminal electrically connected to the first uncoated region and penetrating the first end face of the battery can; and a cap covering and sealing the opening of the second end face of the battery can.