Sintered Lithium Battery Structure for Stable Electrode Bonding
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Solution Overview
Problem
Lithium secondary batteries with sintered plates face challenges in achieving high capacity and charge/discharge efficiency due to low yield during production, primarily due to displacement issues between ceramic positive and negative electrodes and variations in electrode distances, leading to reduced charge/discharge 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 the interface between the negative electrode and ceramic separator having a larger roughness than the interface between the positive electrode and ceramic separator, enhancing bonding strength and production yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an integrated sintered plate configuration is used to minimize electrode displacement, then production yield improves, but manufacturing complexity increases
Solution Approach 1:
The patent merges the positive electrode layer, ceramic separator, and negative electrode layer into a single integrated sintered plate formed by co-sintering. This integration eliminates the need for separate assembly steps and positioning operations, thereby improving production yield while the sintering process itself provides the necessary bonding without requiring additional complex manufacturing steps
Solution Approach 2:
The patent applies preliminary action by forming the integrated sintered plate before battery assembly. The co-sintering process pre-bonds all three layers in their correct relative positions, eliminating the need for subsequent positioning and alignment operations during battery manufacturing, thus improving yield without proportionally increasing manufacturing complexity
2Strength
If interface roughness between negative electrode and ceramic separator is increased to enhance bonding strength, then electrode displacement is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the physical parameter of interface roughness to optimize bonding strength. By controlling the roughness of the negative electrode surface that contacts the ceramic separator, the patent enhances mechanical interlocking and chemical bonding without requiring excessively tight tolerances on other manufacturing parameters
Solution Approach 2:
The patent applies local quality by differentiating the roughness characteristics at different interfaces. The interface between the negative electrode and ceramic separator is designed with larger roughness to maximize bonding, while other interfaces maintain appropriate roughness levels for their specific functions, allowing optimized bonding without uniformly increasing manufacturing precision requirements across the entire structure
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 excellent charge/discharge cycle performance while improving production yield by minimizing electrode displacement and waviness, resulting in a battery with high capacity and efficient charging capabilities.
Implementation Method 1
an interface between the negative electrode layer and the ceramic separator has a larger roughness than an interface between the positive electrode layer and the ceramic separator
Data Source
AI summary
Provided is a lithium secondary battery including 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.