Negative Electrode Film Segmentation for Battery Energy and Cycle Life
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Solution Overview
Problem
Existing secondary batteries face challenges in balancing energy density, dynamic performance, and service life, as improving one aspect often compromises the others.
Innovation Solution
A secondary battery design featuring a negative electrode plate with a specific composition, including a first carbon-based material with a pore structure and a second carbon-based material comprising artificial graphite, which enhances compaction density, active ion transport, and safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the energy density of the secondary battery is improved, then the energy storage capacity increases, but the dynamic performance and service life are affected
Solution Approach 1:
The negative electrode film is divided into two distinct regions: a first region (0-0.3H from the current collector) containing first carbon-based material with pore structure for high energy density, and a second region (0.3H-thickness from the current collector) containing second carbon-based material with different properties for dynamic performance. This spatial segmentation allows each region to optimize for its specific function while working together as a unified electrode system.
Solution Approach 2:
Different regions of the negative electrode film are assigned different material compositions and structures tailored to local functional requirements. The first region near the current collector uses pore-structured material optimized for energy density, while the second region uses material optimized for ion transport and cycling stability. This local quality differentiation resolves the contradiction by allowing high energy density in the first region while maintaining good dynamic performance through the second region's material properties.
2Speed
If the dynamic performance of the secondary battery is improved, then the charging and discharging speed increases, but the energy density is compromised
Solution Approach 1:
The negative electrode film is segmented into two regions with different material compositions: the first region (0-0.3H) contains first carbon-based material optimized for energy density, while the second region (0.3H-thickness) contains second carbon-based material optimized for dynamic performance. This segmentation allows the battery to achieve both high energy density and good dynamic performance by having dedicated zones for each function.
Solution Approach 2:
The second region of the negative electrode film (0.3H to thickness from current collector) is specifically designed with second carbon-based material that has properties optimized for rapid ion transport and electrochemical reactions. This local quality enhancement in the second region enables high dynamic performance without compromising the energy density provided by the first region, as each region performs its specialized function.
3Quantity of substance
If the compaction density of the negative electrode film is increased, then the energy density improves, but the active ion transport speed may be reduced
Solution Approach 1:
The negative electrode film is divided into two regions with different compaction characteristics: the first region (0-0.3H) has high compaction density for energy density, while the second region (0.3H-thickness) maintains optimized porosity and structure for ion transport. This segmentation resolves the contradiction by allowing high compaction in the first region without severely impacting overall ion transport, as the second region provides dedicated ion transport pathways.
Solution Approach 2:
Different regions of the negative electrode film are assigned different compaction densities and pore structures according to local functional needs. The first region near the current collector has high compaction density optimized for energy density, while the second region has material properties and pore structure optimized for active ion transport. This local quality differentiation allows the battery to achieve both high compaction density and maintained ion transport speed.
Data Source
AI summary
A secondary battery including a negative electrode plate including a negative electrode current collector and a negative electrode film formed on at least one surface of the negative electrode current collector is provided, wherein the negative electrode film has a first surface away from the negative electrode current collector and a second surface disposed opposite to the first surface, thickness of the negative electrode film being denoted as H, a region within a thickness ranging from the second surface of the negative electrode film to 0.3 H being denoted as first region of the negative electrode film, a region within a thickness ranging from the first surface of the negative electrode film to 0.3 H being denoted as second region of the negative electrode film.