Secondary Battery Anode Resistance Tuning for Low-Temperature Power
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Solution Overview
Problem
Secondary batteries face challenges in maintaining high energy density while improving low-temperature power performance, as their energy density and low-temperature performance are often compromised by poor resistance control in the negative electrode plate.
Innovation Solution
The secondary battery design incorporates a negative electrode plate with a specific resistance range (6.0 mΩ≤R≤12.0 mΩ or 3.0 mΩ≤R≤7.0 mΩ) and a negative active material comprising both artificial and natural graphite, which enhances energy density and active ion transmission, thereby improving low-temperature power performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative electrode plate uses conventional materials without resistance control, then the manufacturing process is simpler, but the low-temperature power performance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the resistance of the negative electrode plate within a specific range (6.0-12.0 mΩ or 3.0-7.0 mΩ). This resistance parameter control directly improves low-temperature power performance while maintaining manufacturing feasibility, resolving the contradiction between performance improvement and complexity increase.
Solution Approach 2:
The patent uses composite materials in the negative electrode plate, combining artificial graphite and natural graphite. This composite structure enables the electrode to achieve the target resistance range while improving active ion transmission, thus enhancing low-temperature performance without excessive complexity.
2Reliability
If the negative electrode plate resistance is reduced to improve power performance, then the low-temperature performance improves, but the energy density may be compromised
Solution Approach 1:
The patent optimizes the resistance parameter of the negative electrode plate to fall within a specific range rather than simply minimizing it. This balanced parameter control ensures both low-temperature power performance and energy density are maintained, as the resistance is reduced sufficiently to improve power but not so much that it compromises the quantity of active material.
Solution Approach 2:
By combining artificial graphite and natural graphite in the negative electrode plate, the patent achieves a composite structure that provides both low resistance (improving power performance) and high active material content (maintaining energy density). The composite materials complement each other to resolve the contradiction between power and energy.
3Reliability
If the negative electrode plate uses artificial graphite only, then the manufacturing precision is easier to control, but the active ion transmission performance deteriorates
Solution Approach 1:
The patent employs a composite of artificial graphite and natural graphite in the negative electrode plate. This composite structure enhances active ion transmission performance by leveraging the complementary properties of both materials, while the overall resistance can still be controlled within the target range, balancing manufacturing precision with performance.
Solution Approach 2:
The patent applies local quality by using different graphite materials (artificial and natural) in specific proportions within the negative electrode plate. This localized material differentiation optimizes active ion transmission in regions where it is most needed while maintaining overall resistance control, resolving the contradiction between transmission performance and manufacturing precision.
Data Source
AI summary
This application discloses a secondary battery including a positive electrode plate and a negative electrode plate, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode film disposed on a surface of the positive electrode current collector and comprising a positive active material, the negative electrode plate comprises a negative electrode current collector and a negative electrode film disposed on a surface of the negative electrode current collector and comprising a negative active material. The positive active material comprises one or more of layered lithium transition metal oxides and modified compounds thereof, and a resistance R of the negative electrode plate satisfies: 6.0 mΩ≤R≤12.0 mΩ; or the positive active material comprises one or more of lithium-containing phosphates with olivine structure and modified compounds thereof, and a resistance R of the negative electrode plate satisfies: 3.0 mΩ≤R≤7.0 mΩ.