Battery Electrode Stack Conveyance to Prevent Drying Cracks
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Solution Overview
Problem
Existing methods of manufacturing batteries result in cracking of the electrode active material layer due to heat treatment, which reduces its flexibility and increases the likelihood of damage.
Innovation Solution
The method involves roller-conveying a stack with a direction changing roller that widens the stack and changes the conveyance direction by 45° or more, applying a faster circumferential speed to the end portions, and includes drying and laser-heating to reduce cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If heat treatment is applied to dry the electrode active material layer, then moisture is removed and drying is achieved, but the electrode active material layer becomes brittle and cracks occur
Solution Approach 1:
The patent applies preliminary stretching to the electrode active material layer before heat treatment. This pre-stretching creates residual tensile stress that counteracts the compressive stress generated during drying, preventing crack formation while maintaining the necessary moisture removal
Solution Approach 2:
The patent controls the heating rate and temperature parameters during heat treatment to prevent excessive moisture removal that would cause brittleness. By optimizing these thermal parameters, the layer dries adequately while maintaining flexibility
2Reliability
If the electrode active material layer is stretched to apply stress, then crack prevention is improved, but the manufacturing process complexity increases
Solution Approach 1:
The stretching operation is performed as a preliminary step before heat treatment, establishing the necessary stress state in advance. This simple pre-stretching operation, combined with controlled heating, effectively prevents cracks without requiring complex manufacturing equipment or processes
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 effectively reduces cracking of the electrode active material layer by applying stress from multiple directions and maintaining binder flexibility during heat treatment, enhancing the manufacturing process.
Implementation Method 1
roller-conveying a stack such that a conveyance direction of the stack that has been subjected to heating to a temperature of 120° C. or more is changed by 45° or more along a direction changing roller
Implementation Method 2
heating the stack to a temperature of 120° C. or more
Implementation Method 3
drying the electrode active material layer before the roller-conveying. The drying may include heating the stack to a temperature of 120° C. or more
Implementation Method 4
The drying may include laser-heating the stack
Data Source
AI summary
A method of the present disclosure of manufacturing a battery includes roller-conveying a stack such that a conveyance direction of the stack that has been subjected to heating to a temperature of 120° C. or more is changed by 45° or more along a direction changing roller, the stack including a base material layer and an electrode active material layer. Further, in the method of the present disclosure, the direction changing roller is configured to widen the stack.