Battery Manufacturing Method Preventing Electrolyte Volatilization
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Solution Overview
Problem
The existing methods for manufacturing secondary batteries using electrodes with an electrolytic solution suffer from cracking issues during the drying process, leading to reduced battery performance, and heat sealing results in insufficient cycle durability due to electrolyte volatilization.
Innovation Solution
A battery manufacturing method involving a unit cell formation step where positive and negative electrodes with an electrolytic solution are stacked with a separator, followed by heat-sealing the outer peripheral portion and subsequent cooling with a cooling medium to prevent heat transmission and volatilization of the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat sealing is performed on the outer peripheral portion of the unit cell to prevent electrolyte leakage, then sealing reliability is improved, but heat transmission to the electrode active material layers causes electrolyte volatilization and composition changes, reducing cycle durability
Solution Approach 1:
The electrode active material layers are prepared with an electrolyte-containing composition before the heat sealing step. This preliminary preparation ensures that the electrolyte is already integrated into the electrode structure, allowing the subsequent heat sealing to occur without causing electrolyte volatilization or composition changes, thus maintaining cycle durability while achieving reliable sealing
Solution Approach 2:
The invention changes the physical state and composition parameters of the electrode active material layers by incorporating the electrolyte directly into the layer structure. This parameter change transforms the electrolyte from a separate component that could volatilize during heat sealing to an integrated component that remains stable, thereby resolving the contradiction between sealing reliability and cycle durability
2Stability of the object's composition
If electrode active material slurry is dried to form dry electrodes, then electrode structure stability is improved, but cracking occurs during the drying process, reducing battery performance
Solution Approach 1:
The invention changes the processing parameters by eliminating the drying step entirely. Instead of drying the electrode active material slurry to form dry electrodes, the method proceeds directly to heat sealing with the electrolyte-containing slurry. This parameter change prevents the formation of cracks that would otherwise occur during drying, while still achieving the desired electrode structure stability through the integrated electrolyte composition
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 method enhances cycle durability by minimizing heat transmission to the electrode active material layers, maintaining battery performance and preventing changes in the electrode composition.
Implementation Method 1
the outer peripheral portion of the unit cell is cooled by a cooling medium
Implementation Method 2
the seal part disposed at the outer peripheral portion of the unit cell is heat-sealed
Data Source
AI summary
A battery manufacturing method includes forming a unit cell having a positive electrode that is obtained by a positive electrode active material layer containing an electrolytic solution being disposed on a positive electrode current collector, a negative electrode that is obtained by a negative electrode active material layer containing an electrolytic solution being disposed on a negative electrode current collector, and a separator interposed between the positive and negative electrodes. Heat sealing a seal part that is disposed at an outer peripheral portion of the unit cell. Cooling the outer peripheral portion of the unit cell by using a cooling medium after carrying out the heat sealing of the seal part. The method is performed such that the positive electrode and the negative electrode are formed without an application film being subjected to a drying process performed through heating.