Integrated Sintered Lithium Battery Plates for Stable Electrode Bonding
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Solution Overview
Problem
Lithium secondary batteries with sintered plates for positive and negative electrodes face challenges in achieving high capacity and charge/discharge efficiency due to displacement issues during assembly, leading to low production yield and reduced cycle performance.
Innovation Solution
A lithium secondary battery configuration where a positive electrode layer, ceramic separator, and negative electrode layer form an integrated sintered plate with a larger roughness interface between the negative electrode and the ceramic separator, enhancing bonding strength and production yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium secondary battery is produced using separate ceramic positive electrode plate and ceramic negative electrode plate, then high capacity and charge/discharge efficiency can be expected, but displacement issues during assembly occur leading to low production yield
Solution Approach 1:
The patent combines the positive electrode layer, ceramic separator, and negative electrode layer into a single integrated sintered plate formed as one piece during the sintering process. This eliminates the need for separate assembly of multiple components, preventing displacement issues during assembly and improving production yield while maintaining the high capacity and charge/discharge efficiency expected from ceramic electrode plates
2Reliability
If a lithium secondary battery is produced using separate ceramic positive electrode plate and ceramic negative electrode plate, then high capacity can be expected, but displacement issues during assembly occur reducing cycle performance
Solution Approach 1:
The integrated sintered plate structure ensures that the positive electrode layer, ceramic separator, and negative electrode layer are permanently bonded as a single unit, eliminating relative displacement between electrodes during battery operation. This stable configuration preserves the high discharge capacity of ceramic electrodes and significantly improves charge/discharge cycle performance by preventing performance degradation from electrode misalignment
3Manufacturing precision
If a lithium secondary battery uses an integrated sintered plate configuration, then displacement between electrodes is minimized, but bonding strength between layers may be insufficient leading to low production yield
Solution Approach 1:
The patent applies different surface roughness characteristics to different regions of the ceramic separator. Specifically, the surface facing the negative electrode layer is made rougher than the surface facing the positive electrode layer. This localized variation in surface quality enhances bonding strength at the negative electrode interface through increased mechanical interlocking, while maintaining adequate bonding at the positive electrode interface, thereby improving overall production yield of integrated sintered plates
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 configuration allows for high discharge capacity and improved charge/discharge cycle performance while minimizing displacement between electrodes, thereby increasing production efficiency and maintaining high capacity and efficiency.
Implementation Method 1
an interface between the negative electrode layer and the ceramic separator having a larger roughness than the interface between the positive electrode layer and the ceramic separator
Data Source
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AI summary
Provided is a lithium secondary battery that is of the integrated sintered plate type in which a positive electrode layer, a ceramic separator, and a negative electrode layer are bonded together and that can be produced with high yield. The lithium secondary battery includes a positive electrode layer composed of a cobalt-containing lithium complex oxide sintered body, a negative electrode layer composed of a titanium-containing sintered body, a ceramic separator interposed between the positive electrode layer and the negative electrode layer and containing MgO, an electrolytic solution with which the positive electrode layer, the negative electrode layer, and the ceramic separator are impregnated, and an exterior body including a closed space, the closed space accommodating the positive electrode layer, the negative electrode layer, the ceramic separator, and the electrolytic solution, wherein the positive electrode layer, the ceramic separator, and the negative electrode layer are bonded together, and the interface between the negative electrode layer and the ceramic separator has a larger roughness than the interface between the positive electrode layer and the ceramic separator.