Wound Battery Cell U-Shaped Electrode Tabs
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Solution Overview
Problem
Lithium-ion batteries with high energy density and fast charge/discharge rates face limitations due to uncoated active materials, leading to inefficient energy use and high temperatures during charging and discharging, which affects their energy density and safety.
Innovation Solution
A battery cell design featuring a wound structure with U-shaped portions on the electrode plates, including a folded-back segment to enhance energy density and heat dissipation, and strategically placed active material layers to prevent lithium escape and ensure safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a wound structure with one tab per electrode plate is adopted, then the battery structure is simple, but the energy density is limited due to uncoated active material
Solution Approach 1:
The electrode plates are divided into multiple tabs (first tab and second tab) instead of a single tab, allowing segmented collection of active material. This segmentation enables both electrodes to contribute active material to the winding structure, increasing energy density while maintaining structural simplicity.
Solution Approach 2:
The first electrode plate and second electrode plate are nested together in a wound structure with multiple tabs interleaved. The tabs are arranged in a nested pattern where first and second tabs alternate, allowing efficient space utilization and maximizing active material usage within the battery envelope.
2Quantity of substance
If a proportion of active materials is increased for high energy density, then the battery has higher energy density, but heat dissipation becomes faster and temperature rise increases during charge/discharge
Solution Approach 1:
The battery structure transitions from a single-tab planar arrangement to a multi-dimensional wound structure with interleaved first and second tabs. This dimensional change creates multiple heat dissipation pathways and surfaces, allowing heat to escape more efficiently from the bulk active material during charge/discharge cycles.
Solution Approach 2:
The single tab is segmented into multiple tabs (first tab with first and second ends, second tab with first and second ends), creating multiple contact points for current collection and heat dissipation. This segmentation reduces the thermal mass concentration and improves heat distribution and dissipation throughout the battery structure.
3Ease of manufacture
If uncoated active material is left in innermost and outermost cores, then the battery structure is easier to manufacture, but active materials are wasted and energy density is limited
Solution Approach 1:
The first and second tabs are pre-formed with specific configurations (first tab with first and second ends, second tab with first and second ends) before winding. This preliminary preparation ensures that the outermost and innermost regions of the wound structure have proper active material coverage, eliminating the need for post-manufacturing adjustments and maximizing active material utilization.
Solution Approach 2:
The interleaved nested arrangement of first and second tabs ensures that active material is properly positioned at both the innermost and outermost cores of the wound structure. The nested pattern guarantees complete active material coverage throughout the entire winding, eliminating wasted material while maintaining manufacturability.
Data Source
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AI summary
A battery cell includes a wound structure formed by winding a first electrode plate and a spaced second electrode plate. A separator is formed between the first electrode plate and the second electrode plate. The first electrode plate includes a first U-shaped portion, and the second electrode plate includes a second U-shaped portion. The first U-shaped portion includes a first straight segment and a folded-back segment extending from the first straight segment. The second U-shaped portion faces the first U-shaped portion and forms a mating structure. The second U-shaped portion includes a first bent area. A surface of the second U-shaped portion facing a center of the battery cell is close to a bent area of the second U-shaped portion. The folded-back segment has the same bending direction as the second U-shaped portion. The disclosure also provides a battery using the battery cell.