Battery Module Busbar Welding Paths to Limit Cell Overheating
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Solution Overview
Problem
Existing welding techniques for connecting busbars to battery cells in energy storing systems are inefficient and can lead to overheating of the battery cells due to the need for multiple welds while the cells are partially charged, which can render them inoperable if left uncharged for extended periods.
Innovation Solution
A method using a laser-welding system with a scanning head and robot arm to clamp and weld busbar tabs to battery poles in a controlled sequence, limiting temperature exposure by separating welding paths and allowing cooling between segments, and using electrically and thermally insulating clamping elements to manage heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent welds are performed on battery cells while they are partially charged, then the battery cells can be connected in electrical circuit, but the battery cells may overheat and become inoperable
Solution Approach 1:
The welding path is divided into multiple discrete welding segments rather than performing continuous welding. The method welds along a first welding path segment, then a second welding path segment, and finally a third welding path segment, with cooling periods between segments. This segmentation allows the battery cell to cool down between welding operations, preventing overheating while completing all necessary welds.
Solution Approach 2:
The welding process uses periodic action by alternating between welding phases and cooling phases. During welding phases, the laser welds along specific path segments; during cooling phases, the battery cell temperature decreases before the next welding segment begins. This periodic cycle of welding and cooling prevents temperature accumulation that would otherwise cause overheating.
2Reliability
If welding is performed on charged battery cells, then the battery cells remain operational, but the welding process becomes more complex and time-consuming
Solution Approach 1:
The welding path is divided into multiple discrete welding segments rather than performing continuous welding. The method welds along a first welding path segment, then a second welding path segment, and finally a third welding path segment, with cooling periods between segments. This segmentation allows the battery cell to cool down between welding operations, preventing overheating while completing all necessary welds.
Solution Approach 2:
The welding process uses periodic action by alternating between welding phases and cooling phases. During welding phases, the laser welds along specific path segments; during cooling phases, the battery cell temperature decreases before the next welding segment begins. This periodic cycle of welding and cooling prevents temperature accumulation that would otherwise cause overheating.
3Reliability
If multiple welds are performed sequentially on battery poles, then complete electrical connection is achieved, but the welding time increases and productivity decreases
Solution Approach 1:
The welding path is divided into multiple discrete welding segments rather than performing continuous welding. The method welds along a first welding path segment, then a second welding path segment, and finally a third welding path segment, with cooling periods between segments. This segmentation allows the battery cell to cool down between welding operations, preventing overheating while completing all necessary welds.
Solution Approach 2:
The welding process uses periodic action by alternating between welding phases and cooling phases. During welding phases, the laser welds along specific path segments; during cooling phases, the battery cell temperature decreases before the next welding segment begins. This periodic cycle of welding and cooling prevents temperature accumulation that would otherwise cause overheating.
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
The method reduces overheating risks, enhances welding efficiency, and maintains battery functionality by minimizing the time cells are charged, thus improving the assembly process.
Implementation Method 1
method for laser-welding a busbar to a plurality of battery cells with a laser-welding system
Implementation Method 2
using electrically and thermally insulating clamping elements to manage heat
Data Source
AI summary
A method for laser-welding a busbar to battery cells with a laser-welding system having a laser scanning head, the busbar having a first and second tabs, the battery cells having first and second poles. The first pole is welded to the first tab along a first welding path segment while the first pole and the first tab are clamped, with an extent of the first welding path segment being limited to limit a temperature at the first pole. Subsequently to said welding along the first welding path segment, the second pole is welded to the second tab along a second welding path segment while the second pole and the second tab are clamped, thereby allowing the temperature at the first pole to decrease. Subsequently to said allowing the temperature at the first pole to decrease, the first pole is welded to the first tab along a third welding path segment.