Lithium Manganese Phosphate Cathode Coating for High-Temperature Cycling
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Solution Overview
Problem
Lithium manganese phosphate positive electrode active materials exhibit poor rate performance and cycling performance, necessitating improvements in structural stability and ion migration to enhance energy density and safety.
Innovation Solution
A core-shell structured positive electrode active material with an inner core of Li1+xMn1-yAyP1-zRzO4, clad with pyrophosphate and phosphate layers, and a carbon-containing outer layer, combined with specific additives in the non-aqueous electrolyte solution, to inhibit manganese dissolution and promote lithium ion migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a large number of batteries are assembled in series to achieve high voltage, then the output voltage is improved, but the internal resistance increases and battery life is reduced
Solution Approach 1:
The battery pack is divided into multiple battery groups, each group containing batteries connected in series. Multiple groups are then connected in parallel. This segmentation allows the system to achieve high voltage through the series connection within groups while the parallel connection between groups reduces overall internal resistance and extends battery life.
2Reliability
If batteries are connected in parallel to reduce internal resistance, then battery life is improved, but the overall voltage is reduced
Solution Approach 1:
The battery pack is divided into multiple battery groups, each group containing batteries connected in series to maintain high voltage. Multiple such groups are then connected in parallel, which reduces overall internal resistance and extends battery life while preserving the high voltage output capability of each individual group.
3Power
If different types of batteries are mixed to optimize performance, then power output is improved, but manufacturing precision and consistency are reduced
Solution Approach 1:
The battery pack is divided into multiple battery groups that can be configured with different battery types or specifications. Each group can be optimized for specific performance characteristics while maintaining overall system balance through the parallel connection architecture, allowing flexible optimization without compromising manufacturing consistency within each group.
Data Source
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AI summary
The present application provides a secondary battery, a battery module, a battery pack and an electrical apparatus. The secondary battery includes a positive electrode plate and a non-aqueous electrolyte solution. A positive electrode active material includes an inner core and a shell cladding the inner core. The inner core includes Li1+xMn1-yAyP1-zRzO4. The shell includes a first cladding layer cladding the inner core and a second cladding layer cladding the first cladding layer. The first cladding layer includes pyrophosphate MP2O7 and phosphate XPO4. The second cladding layer includes carbon. The non-aqueous electrolyte solution includes a first additive. The first additive includes one or more compounds in a group consisting of a compound shown in Formula 1, a compound shown in Formula 2 and a compound shown in Formula 3. The rate performance, cycling performance and high temperature stability of a lithium manganese phosphate secondary battery are increased.