Electrode Stack Joining with Two-Step Pressing for Uniform Bonding
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Solution Overview
Problem
The existing electrode assembly manufacturing process in secondary batteries faces issues with misalignment and inconsistent bonding forces, leading to non-uniformity and potential defects due to varying bonding strengths across the stack.
Innovation Solution
An electrode assembly joining apparatus and method that utilizes a gripper to hold a stack of electrodes and separators, with a press part for bonding and a stack movement part to support and partially move the stack, allowing for two bonding processes in a single chamber to ensure uniform bonding forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodes and separators are heated and stacked with simultaneous pressing, then bonding is achieved across layers, but bonding force uniformity deteriorates due to single pressing process
Solution Approach 1:
The patent divides the bonding process into two separate pressing steps: a first pressing process that bonds initial layers, and a second pressing process that bonds remaining layers. This segmentation allows each pressing operation to be optimized independently, ensuring uniform bonding force distribution across all layers of the electrode assembly.
Solution Approach 2:
The patent implements periodic pressing actions with alternating engagement and disengagement of the pressing mechanism. The first pressing process operates periodically to bond initial layers, followed by a second pressing process for remaining layers. This periodic action enables controlled, staged bonding that maintains force uniformity throughout the assembly.
2Strength
If single pressing process is used for stacked electrodes, then process simplicity is maintained, but bonding force decreases in stacking direction
Solution Approach 1:
The patent applies preliminary pressing action in the first pressing process to bond the initial layers of electrodes and separators. This preliminary bonding establishes a stable foundation before the second pressing process bonds the remaining layers, ensuring cumulative bonding force strength throughout the stacking direction while maintaining efficient manufacturing throughput.
3Reliability
If electrodes are pressed multiple times for bonding, then bonding force of initial layers increases, but level difference occurs between surfaces
Solution Approach 1:
The patent applies local quality by directing the first pressing process to bond specific initial layers while leaving other layers for the second pressing process. Each pressing operation targets specific regions of the stack, ensuring that bonding force is distributed locally and uniformly across different layers without causing surface level differences or deformation.
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 minimizes non-pressed and doubly pressed areas, prevents height differences, and enhances the uniformity of bonding forces and ventilation, improving the quality and consistency of the electrode assembly.
Implementation Method 1
bonding the negative electrode and the separator and bonding the positive electrode and the separator by heating and pressing
Data Source
AI summary
An electrode assembly joining apparatus includes a gripper, a press part, and a stack movement part. The gripper holds a part of a stack in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked with separators disposed therebetween. The press part bonds the stack, and the stack movement part supports the stack or moves the stack partially. A method of manufacturing the same is also provided.