Wound Battery Separator Fixation via Heat Welding
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Solution Overview
Problem
The existing methods for manufacturing batteries with wound electrode assemblies often result in the outermost portion of the separator being turned up during insertion, causing stress and potential damage, leading to internal short-circuits and damage to the electrode plates.
Innovation Solution
A method involving the use of heat welding to fix both lateral ends of the separator's outermost portion to the wound electrode assembly, ensuring the separator remains flat and preventing turning up, while using adhesive tape to secure the terminal end and employing a tilted heat welding probe to minimize damage to the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive tape is applied to the terminal end of the separator along the entire width, then the separator is fully secured, but the electrode plates are damaged due to pressing against void regions
Solution Approach 1:
The adhesive tape is applied only to specific regions (central portion and connection portions) rather than the entire width of the separator. This local application strategy secures the separator where needed while avoiding the void regions at the lateral ends where electrode plates would be damaged by pressing.
2Reliability
If adhesive tape is applied to secure the separator, then the separator is fixed, but the outermost portion may still turn up during insertion
Solution Approach 1:
The separator fixation is divided into multiple segments: the terminal end is fixed with adhesive tape, and the lateral ends of the outermost portion are fixed with heat-welded portions. This segmented approach ensures both the terminal end and lateral ends are secured, preventing the separator from turning up during insertion.
Solution Approach 2:
Heat-welded portions are formed in advance at the lateral ends of the outermost portion of the separator before insertion. This preliminary action ensures that when the separator is inserted, the lateral ends are already fixed and cannot turn up, maintaining separator flatness throughout the insertion process.
3Reliability
If heat welding is performed on the separator, then the lateral ends are fixed, but the electrode plates may be damaged by the heat welding process
Solution Approach 1:
Heat welding is applied only to specific regions (lateral ends of the outermost portion) rather than the entire separator. This localized heat welding secures the lateral ends while avoiding the electrode active material-coated portions, preventing damage to the electrode plates.
4Ease of operation
If the wound electrode assembly is inserted with the outermost portion of the separator turned up, then insertion is possible, but stress is applied causing damage and internal short-circuit
Solution Approach 1:
The lateral ends of the outermost portion of the separator are pre-fixed with heat-welded portions before insertion. This preliminary fixation ensures that during insertion, the separator remains flat and cannot turn up, eliminating stress concentration and preventing damage that would lead to internal short-circuits.
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 prevents the separator from turning up and reduces the risk of damage to the electrodes and separator during manufacturing, maintaining the integrity of the battery's power storage capability.
Implementation Method 1
performing heat welding on parts of both lateral ends of an outermost portion of the separator in the wound electrode assembly which are located above the electrode active material-uncoated portion of the positive electrode plate or the electrode active material-uncoated portion of the negative electrode plate to fix the lateral ends to the wound electrode assembly
Implementation Method 2
fixing a part of a terminal end of the separator in a lateral direction to the wound electrode assembly
Data Source
AI summary
A battery manufacturing method includes: winding positive and negative electrode plates and a separator to form a wound electrode assembly; cutting unwound portions of the positive and negative electrode plates and the separator such that the separator constitutes an outermost layer of the wound electrode assembly when the winding is completed; further winding around the wound electrode assembly the cut unwound portions; fixing a part of a terminal end of the separator in a lateral direction to the wound electrode assembly; and performing heat welding on parts of both lateral ends of an outermost portion of the separator in the wound electrode assembly, which are located above an electrode active material-uncoated portion of the positive or negative electrode plate to fix the lateral ends to the wound electrode assembly.