Positive Electrode Composition Balancing Ni Energy and Thermal Stability
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Solution Overview
Problem
Secondary batteries face challenges in achieving high energy density and safety performance, particularly due to the negative impact of Ni element and the need for improved thermal stability.
Innovation Solution
A positive electrode plate with controlled mass proportions of Ni, Fe, Mn, and Al elements, combined with specific active materials and electrolyte management, enhances safety and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the mass proportion of Ni element in the positive electrode film layer is increased to achieve higher energy density, then the energy density is improved, but the safety performance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mass proportion of Ni element in the positive electrode film layer within the range of 2.88%-86.10%, and further optimizing it to 40%-70% for best results. This quantitative parameter optimization resolves the contradiction by finding the optimal balance point where energy density is maximized while safety performance is maintained through the specified compositional range.
Solution Approach 2:
The patent employs composite materials by combining multiple elements (Ni, Fe, Mn, and Al) in specific proportions within the positive electrode film layer. This composite approach allows the system to benefit from Ni's high energy density contribution while the other elements contribute to thermal stability and safety, thereby resolving the contradiction between energy density and safety performance.
2Use of energy by moving object
If the mass proportion of Ni element is increased to improve energy density, then the energy density is improved, but the thermal stability deteriorates
Solution Approach 1:
The patent optimizes the mass proportion parameters of multiple elements simultaneously, setting Ni content to 40%-70% while controlling Fe, Mn, and Al content to achieve the desired balance. This parameter optimization ensures that energy density is improved through adequate Ni content while thermal stability is maintained through the controlled composition of other elements.
Solution Approach 2:
The patent converts the potentially harmful effect of high Ni content (which reduces thermal stability) into a benefit by carefully controlling its proportion within the optimal range. Simultaneously, the presence of other elements like Fe, Mn, and Al in controlled amounts compensates for the thermal instability, transforming the harmful effect into a balanced composition that achieves both high energy density and adequate thermal stability.
Data Source
AI summary
A positive electrode sheet, a battery, and an electric device are disclosed. The positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector; the positive electrode film layer comprises a positive electrode active material; the positive electrode active material comprises an element Ni, an element Fe, an element Mn, and an optional element Al; and the positive electrode sheet satisfies the following:0<CNi/(CNi+CFe+CMn+CAl)≤90.1%.