Battery Insulation via Cathode Anode Lead Inversion
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Solution Overview
Problem
Lithium ion batteries face safety issues due to short circuits caused by the deviation of active-material coating layers on cathode and anode collectors, leading to electrical insulation failures and heat emission, particularly at uncoated parts where no active-material coating layer is present.
Innovation Solution
The battery design includes arranging cathode and anode leads in opposite directions and attaching an insulator tape to the boundary of the cathode active-material coating layer where the anode active-material coating layer faces a cathode uncoated part, ensuring enhanced electrical insulation and safety by preventing contact between uncoated parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If active-material coating layers are applied to both surfaces of cathode and anode collectors, then energy density is improved, but electrical insulation is worsened due to short circuits at uncoated parts
Solution Approach 1:
The cathode and anode collectors are segmented into coated regions and uncoated regions, with the uncoated parts positioned at opposite ends to prevent contact. This segmentation allows the battery to maintain high energy density from dual-surface coating while avoiding short circuits by spatially separating conductive regions.
Solution Approach 2:
The cathode and anode are designed with asymmetric lead arrangements where cathode leads and anode leads are positioned at opposite ends of the wound structure. This asymmetric configuration ensures that uncoated parts of opposite polarity do not contact each other, resolving the electrical insulation problem while maintaining high energy density.
2Ease of manufacture
If cathode and anode leads are arranged in the same direction, then manufacturing is simplified, but short circuit risk increases at uncoated parts
Solution Approach 1:
Instead of arranging both leads in the same direction (conventional approach), the invention inverts the arrangement by positioning cathode and anode leads at opposite ends. This inversion eliminates the short circuit hazard while the winding process itself remains straightforward, maintaining ease of manufacture.
3Reliability
If active-material coating layers are longitudinally deviated, then electrical insulation is improved, but energy density is worsened due to reduced active material utilization
Solution Approach 1:
The invention applies local quality by coating both surfaces of collectors with active material (high energy density) while creating localized uncoated regions at specific positions (opposite ends) for electrical insulation. This allows the majority of the collector surfaces to be utilized for energy storage while minimal uncoated regions provide safety function.
Data Source
AI summary
Disclosed is a battery including a cathode in which cathode active-material coating layers provided on both surfaces of a cathode collector are longitudinally deviated from each other, and an anode having at least one anode active-material coating layer provided on an anode collector, the cathode and anode being wound to face each other with a separator interposed therebetween. At least one of a winding beginning portion and winding ending portion of the cathode is provided with a cathode uncoated part for installation of a cathode lead. An insulator tape is attached to the boundary of the cathode active-material coating layer at a position where the anode active-material coating layer faces a non-coating part of the cathode not containing the cathode active-material coating layer, achieving enhanced electrical insulation capability and consequential safety of the battery.