Battery Cell Shell Welding Layout for Crack-Resistant Thin Plates
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Solution Overview
Problem
The shell of battery cells is prone to breakage due to internal expansion or external stress, affecting the reliability of the battery.
Innovation Solution
Adjust the welding process to locate welding pores primarily in a thicker first plate portion of the shell, reducing their impact on a thinner second plate portion, thereby enhancing the structural integrity and reliability of the battery cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the shell is made thinner to reduce weight and material cost, then the weight and cost decrease, but the strength and reliability of the battery cell deteriorate
Solution Approach 1:
The shell is designed with non-uniform thickness: the first plate portion has a first thickness while the second plate portion has a second thickness greater than the first thickness. This local quality variation allows the shell to maintain overall lightness while providing enhanced strength at critical locations (second plate portion) where welding pores are present and stress concentration occurs, thereby resolving the contradiction between weight reduction and reliability improvement.
2Strength
If welding is performed to join the plate portions, then the structural integrity is improved, but welding pores are formed which reduce the strength of the shell
Solution Approach 1:
The invention strategically locates welding pores in the first plate portion rather than the second plate portion. By extracting the harmful welding pores from the critical second plate portion and concentrating them in the first plate portion, the negative impact of welding pores on shell strength is minimized while maintaining the necessary structural integrity through the welding joint.
Solution Approach 2:
The shell employs non-uniform thickness distribution where the second plate portion has greater thickness than the first plate portion. This local quality enhancement at the second plate portion compensates for the strength reduction caused by welding pores, allowing the shell to maintain adequate strength while still permitting welding to be performed for structural integrity.
3Loss of substance
If the second plate portion is made thinner to reduce material usage, then material cost and weight decrease, but the resistance to cracking and breakage deteriorates
Solution Approach 1:
The shell is designed with differentiated thickness: the first plate portion has a first thickness while the second plate portion has a second thickness greater than the first thickness. This local quality variation allows material reduction in the first plate portion (reducing overall material usage) while maintaining adequate strength and crack resistance in the second plate portion where welding pores are located and stress concentration occurs.
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 solution effectively reduces the risk of cracking and breakage in the thinner plate portion, improving the overall reliability and service life of the battery cell.
Implementation Method 1
The first plate portion is welded to the second plate portion to form a molten pool structure and welding pores located in the molten pool structure
Data Source
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AI summary
This application provides a battery cell, a battery, an electrical device, and a method for preparing a battery cell. The battery cell includes a shell and an electrode assembly. The shell provides an accommodation space. The shell includes a first plate portion and a second plate portion. The first plate portion is welded to the second plate portion to form a molten pool structure and welding pores located in the molten pool structure. The electrode assembly is accommodated in the accommodation space. A thickness of the first plate portion is greater than a thickness of the second plate portion. At least a part of the welding pores are located in the first plate portion. In some embodiments of this application, the welding process of the first plate portion and the second plate portion is adjusted, so that at least a part of the welding pores can be located in the first plate portion. Because at least a part of the welding pores can be located in the first plate portion, the number of welding pores located in the second plate portion is reduced, thereby reducing the impact caused by the welding pores onto strength of the second plate portion, and improving reliability of the battery cell in use.