Negative Electrode Compression with In-Press Pre-Lithiation
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Solution Overview
Problem
Current methods for pre-lithiation of lithium secondary batteries are costly and inefficient, particularly for mass production, and result in significant irreversible capacity loss due to the formation of a solid electrolyte interphase (SEI) film, which affects the initial charge and discharge cycles.
Innovation Solution
A method for manufacturing a lithium secondary battery negative electrode that involves forming a lithium alloy layer on the press plates in contact with the negative electrode active material during compression, allowing pre-lithiation to occur without a separate pre-lithiation process, thereby reducing irreversible capacity loss and improving electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate pre-lithiation process is performed, then the initial reversibility is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the pre-lithiation function into the compression press by forming lithium alloy layers on the press plates. This merges two separate processes (compression and pre-lithiation) into one, eliminating the need for a dedicated pre-lithiation device while achieving the same technical effect of improving initial reversibility
Solution Approach 2:
The compression press is transformed into a multi-functional device that performs both mechanical compression and pre-lithiation simultaneously. The press plates with lithium alloy layers serve dual purposes: applying compression force and providing lithium ions to the negative electrode, thereby eliminating the need for separate pre-lithiation equipment
2Reliability
If a separate pre-lithiation process is performed, then the irreversible capacity loss is reduced, but the manufacturing time and productivity decrease
Solution Approach 1:
The patent merges the pre-lithiation step with the compression step, so that both operations occur simultaneously during a single manufacturing cycle. This eliminates the additional time required for separate pre-lithiation processes while still achieving reduced irreversible capacity loss
Solution Approach 2:
The lithium alloy layers are pre-formed on the press plates before the actual electrode manufacturing. This preliminary preparation allows the pre-lithiation to occur automatically during compression without requiring additional processing time during the main manufacturing cycle, thereby maintaining high productivity
3Reliability
If lithium alloy layers are formed on press plates, then pre-lithiation is achieved during compression, but the manufacturing cost increases
Solution Approach 1:
The compression press itself provides the pre-lithiation function through the lithium alloy layers on its plates. The system uses its own structure (the press plates) to deliver lithium ions during the normal compression operation, eliminating the need for external pre-lithiation equipment and reducing overall manufacturing cost despite the added material
4Manufacturing precision
If the negative electrode is compressed with a press, then the electrode structure is formed, but pre-lithiation is not achieved without additional processes
Solution Approach 1:
The compression press is designed to perform multiple functions: it applies mechanical compression to form the electrode structure and simultaneously provides lithium ions through the lithium alloy layers on its plates. This multi-functionality ensures both proper electrode formation and pre-lithiation occur during the same operation
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
This approach enables efficient pre-lithiation during the manufacturing process, enhancing the initial reversibility and cycle life of lithium secondary batteries by minimizing the formation of the SEI film and eliminating the need for a separate pre-lithiation step, thus improving the battery's overall performance.
Implementation Method 1
a lithium alloy layer is formed on a portion in contact with a negative electrode active material layer of upper and lower plates of the press for compression, and pre-lithiation of the negative electrode is performed at the time of compression
Data Source
AI summary
A method for manufacturing a negative electrode for a lithium secondary battery is provided in which the method is capable of effectively performing pre-lithiation. While a negative electrode is compressed with a press, a lithium alloy layer is formed on a portion in contact with a negative electrode active material layer of upper and lower plates of the press, and a negative electrode tab is electrically connected to the press through a connection part respectively disposed on the upper and lower plates of the press, and thus, it is possible to manufacture a negative electrode for a lithium secondary battery in which the pre-lithiation of the negative electrode may be performed at time of compression even without a separate pre-lithiation process.