Wound Electrode Assembly with Bent Collectors for Higher Energy Density
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Solution Overview
Problem
The energy densities of existing electrode assemblies in lithium batteries are insufficient, leading to performance limitations in energy storage devices, and there is a risk of lithium dendrite formation causing short circuits due to inadequate design of the negative electrode.
Innovation Solution
The electrode assembly features a multi-layer winding structure with current collector units bent at angles between 0° to 90°, forming positive and negative electrode tabs that improve battery capacity and energy density, while the 'overhang' design enhances the negative electrode's ability to receive lithium ions, preventing dendrite formation and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional electrode assembly design is used, then manufacturing simplicity is maintained, but energy density is insufficient
Solution Approach 1:
The current collector is divided into multiple current collector units (first, second, third units) with different configurations. Each unit has specific bending angles and arrangements that optimize lithium ion reception and current collection efficiency, thereby increasing energy density while maintaining manageable structural complexity through modular design
Solution Approach 2:
The current collector units are bent at specific angles (e.g., 45°, 60°, 90°) relative to the electrode assembly axis, creating three-dimensional spatial arrangements. This dimensional transformation allows better utilization of space and improves lithium ion access to active materials, enhancing energy density without excessive complexity increase
2Reliability
If negative electrode design is inadequate, then manufacturing is simpler, but lithium dendrite formation risk increases
Solution Approach 1:
The negative electrode current collector units are specifically designed with different bending angles and arrangements in different regions. The first current collector unit has a specific configuration optimized for dendrite prevention, while other units have different configurations. This localized optimization enhances reliability by addressing dendrite formation risks at critical locations without requiring complete redesign of the entire electrode structure
Solution Approach 2:
The current collector units are pre-bent at specific angles during manufacturing to create optimal lithium ion reception geometry before assembly. This preliminary structuring ensures that lithium ions are evenly distributed and received during initial charging cycles, preventing dendrite formation from the outset without requiring complex operational controls
3Quantity of substance
If current collector units are bent at optimal angles, then energy density improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies ranges for bending angles (e.g., 45°, 60°, 90°) rather than requiring exact single values. This parameter optimization approach allows manufacturing within acceptable tolerances while still achieving the desired energy density improvement. The design accommodates normal manufacturing variations without compromising performance significantly
Solution Approach 2:
The current collector units are bent at angles that may be slightly more extreme than minimum required (e.g., using 90° bends where smaller angles might suffice). This excessive action ensures that even with manufacturing tolerances, the lithium ion reception capability remains sufficient, trading some manufacturing precision for robustness and energy density
Data Source
AI summary
The present application provides an electrode assembly and an energy storage device. The electrode assembly includes an electrode assembly body and a current collector. The electrode assembly body is wound in shape; the current collector is arranged at an end of the electrode assembly body and includes multiple current collector units each bent towards an axis of the electrode assembly body, and an angle between each current collector unit and the axis of the electrode assembly body is in a range from approximately 0° to approximately 90°.