Composite Positive Electrode Plate for Dense Li-Ion Cathode Packing
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Solution Overview
Problem
Existing lithium-ion battery technologies face challenges in mixing lithium manganese iron phosphate, ternary, and lithium manganese oxide materials due to particle size, density, and pH differences, leading to uneven particle distribution and reduced compacted density, energy density, and cycling performance.
Innovation Solution
A positive electrode plate design with a composite structure of spinel lithium manganese oxide and ternary materials, where the primary particle size of the ternary material is controlled to be 3.2 times larger than the spinel material, and pH values are utilized to optimize compacted density and balance the slurry stability, enhancing cycling performance and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If three materials (ternary, lithium manganese oxide, and lithium manganese iron phosphate) are mixed directly to form a slurry, then the electrode plate can be prepared with multiple material benefits, but the particle size, density, and pH value differences make it difficult to mix uniformly, leading to poor electrode plate processing and uneven particle distribution
Solution Approach 1:
The patent divides the electrode plate into two separate active material layers: a first layer containing ternary and lithium manganese oxide materials, and a second layer containing lithium manganese iron phosphate material. This segmentation allows each layer to be optimized independently for its specific material characteristics, avoiding mixing difficulties while still achieving the combined benefits of all three materials in a single electrode plate structure.
2Stability of the object's composition
If ternary material and lithium manganese iron phosphate material are prepared as separate coatings, then the mixing difficulty is avoided, but the gap filling effect cannot be utilized and the compacted density decreases
Solution Approach 1:
The patent employs a nested structure where the first active material layer (containing ternary and lithium manganese oxide) and the second active material layer (containing lithium manganese iron phosphate) are stacked together on the current collector. This nested arrangement allows the smaller particles of lithium manganese iron phosphate to fill the gaps between larger ternary material particles, maximizing space utilization and achieving high compacted density while maintaining separate coating benefits.
3Quantity of substance
If lithium manganese oxide with lower cost is mixed with lithium manganese iron phosphate, then the cost is reduced and energy density is improved, but the dual voltage platform makes BMS design more difficult and cycling stability decreases
Solution Approach 1:
The patent applies local quality by creating distinct regions with different material compositions optimized for different functions. The first layer (ternary + lithium manganese oxide) is optimized for high energy density and voltage, while the second layer (lithium manganese iron phosphate) is optimized for cycling stability and low-temperature performance. This local differentiation allows each material to contribute its strengths without the drawbacks of mixing, achieving both high energy density and reliable cycling stability.
4Volume of stationary object
If the primary particle size of ternary material is controlled to be 3.2 times larger than spinel material, then the stacked-compacted density is optimized and volumetric energy density increases, but the mixing and distribution control becomes more complex
Solution Approach 1:
The patent applies parameter changes by establishing a specific quantitative relationship between particle sizes (D2 ≥ 3.2*D1) to optimize the electrode plate's compacted density. This parameter control ensures that smaller spinel particles fill the interstices between larger ternary particles, maximizing space utilization and achieving high volumetric energy density. The clear numerical guideline simplifies the manufacturing process by providing a concrete target for particle size control.
Data Source
Figure 1~2
AI summary
The present disclosure provides a positive electrode plate and a lithium-ion battery using the positive electrode plate. The positive electrode plate includes a current collector and a positive electrode active material layer. The positive electrode active material layer includes a first active material layer and a second active material layer, both of which are provided in a composite manner. The first active material includes a spinel lithium manganese oxide material and a ternary material, and the second active material layer includes a phosphate material; single crystal sizes of the spinel lithium manganese oxide material and the ternary material are D1 and D2, respectively, which meet a condition D2 ≥ 3.2*D1.