Lithium-Ion Battery Electrode Composition for Voltage Plateau Matching
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Solution Overview
Problem
Conventional lithium-ion batteries face challenges in achieving high specific capacity and safety performance simultaneously due to mismatched voltage plateaus of lithium iron phosphate and NCM ternary materials, leading to low capacity and safety issues.
Innovation Solution
A lithium-ion battery design incorporating a positive electrode active material composed of lithium manganese iron phosphate and a ternary material, with a negative electrode active material comprising carbon and silicon oxide, and a lithium replenishing layer to ensure active lithium content, optimizing the mass percentages and compaction densities of the electrode materials and the separator layers for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium iron phosphate and NCM ternary material are used in combination, then the voltage plateau mismatch occurs, but the specific capacity and safety performance deteriorate
Solution Approach 1:
The patent modifies the voltage parameters by introducing a voltage matching layer that adjusts the voltage plateau of the NCM ternary material to match lithium iron phosphate. This parameter change resolves the voltage mismatch issue, enabling both materials to work together effectively while maintaining high specific capacity and safety performance.
Solution Approach 2:
The patent creates a composite electrode structure combining lithium iron phosphate, NCM ternary material, and a voltage matching layer. This composite approach allows the system to leverage the safety advantages of lithium iron phosphate while maintaining the high capacity benefits of NCM ternary material, resolving the contradiction between safety and capacity.
2Quantity of substance
If lithium iron phosphate and NCM ternary material are used in combination, then the voltage plateau mismatch occurs, but the safety performance deteriorates
Solution Approach 1:
The voltage matching layer changes the voltage parameters of the NCM ternary material interface, adjusting its voltage plateau to match lithium iron phosphate. This parameter modification enables safe operation while maintaining high specific capacity by preventing the harmful effects of voltage mismatch.
Solution Approach 2:
The voltage matching layer acts as an intermediary between lithium iron phosphate and NCM ternary material, mediating the voltage interface to prevent direct harmful interactions. This intermediary layer enables the system to achieve both high capacity and safety by facilitating compatible voltage operation between the two materials.
3Reliability
If conventional lithium iron phosphate and NCM ternary material combination is used, then the voltage plateau mismatch occurs, but the energy density is limited
Solution Approach 1:
By changing the voltage parameters through the voltage matching layer, the patent enables the NCM ternary material to operate at voltages compatible with lithium iron phosphate. This parameter adjustment unlocks the full energy potential of the NCM material while maintaining voltage matching, thereby increasing overall energy density.
Solution Approach 2:
The composite structure incorporating voltage matching layer enables synergistic operation of lithium iron phosphate and NCM ternary material. This composite approach maximizes energy utilization by allowing both materials to contribute their full capacity without the limitations imposed by voltage mismatch, achieving high energy density.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The battery achieves enhanced specific capacity, extended cycle life, and improved safety with energy density exceeding 250 Wh/kg and capacity retention rate of 76% after 2000 cycles, along with a higher DSC trigger temperature, ensuring safe operation.
Implementation Method 1
an areal density of lithium in the lithium replenishing layer is m2=a*M1*m1*δ*(1−η)/M2
Data Source
AI summary
Provided is a lithium-ion battery, including a positive electrode plate, a separator, and a negative electrode plate. The separator is arranged between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active layer laminated in sequence. A positive electrode active material in the positive electrode active layer includes lithium manganese iron phosphate and a ternary material. The negative electrode plate includes a negative electrode current collector and a negative electrode active layer laminated in sequence. The negative electrode active layer includes a composite layer and a lithium replenishing layer. A negative electrode active material in the composite layer includes a carbon material and SiOx. An areal density of lithium in the lithium replenishing layer is m2=a*M1*m1*δ*(1−η)/M2.