Battery Cell Tab Welding Structure to Prevent Cracking
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Solution Overview
Problem
The existing manufacturing methods for battery cells often result in electrode tab disconnection and cracking due to excessive welding energy or pressure, which can lead to separation between the electrode lead and tab, compromising the integrity of the battery cell.
Innovation Solution
The battery cell design incorporates a pre-welding portion with specific edge configurations and overlapping welding spots in the main welding portion to distribute stress and prevent cracking, along with a manufacturing method that forms these portions to reduce disconnection risks, including the use of ultrasonic and laser welding techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high welding energy or pressing force is applied to strengthen the welding of electrode tabs, then the welding strength is improved, but cracks are generated in the electrode tab
Solution Approach 1:
The patent applies different welding parameters to different regions of the electrode tab. The welding portion is designed with specific local characteristics including a width that is 0.3-0.7 times the tab width, and welding energy that is 30-70% of the total tab energy. This localized quality approach allows strong welding at the connection point while preventing excessive stress and crack formation in other areas of the tab.
Solution Approach 2:
The patent optimizes welding parameters including pressing force (1-5 tons), welding energy (30-70% of total tab energy), and welding time (0.1-1 second) to achieve the desired balance between welding strength and crack prevention. By carefully controlling these parameters, the welding portion achieves sufficient strength without generating harmful cracks in the electrode tab.
2Reliability
If excessive welding energy is applied to prevent separation between electrode lead and tab, then the connection strength is improved, but the electrode tab structure is damaged
Solution Approach 1:
The welding portion is designed with specific local characteristics including a width that is 0.3-0.7 times the tab width, and welding energy that is 30-70% of the total tab energy. This localized quality approach allows strong welding at the connection point while preventing excessive stress and crack formation in other areas of the tab.
Solution Approach 2:
The patent applies welding energy that is 30-70% of the total tab energy, which is sufficient to achieve reliable connection between the electrode lead and tab without applying excessive energy that would damage the tab structure. This partial action approach ensures adequate connection strength while preserving tab integrity.
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 design effectively reduces the risk of electrode tab disconnection and cracking by optimizing the position and size of welding portions, enhancing the structural integrity and reliability of the battery cell.
Implementation Method 1
a pre-welding portion (200) on the electrode tab (120), wherein the pre-welding portion (200) is formed by a welding device using ultrasonic vibration
Implementation Method 2
a main welding portion (300) for connecting the electrode lead (130) to one surface of the electrode tab (120), wherein at least a part of the main welding portion (300) and the pre-welding portion (200) overlap each other
Data Source
AI summary
A battery cell according to one embodiment of the present disclosure includes a stacked body including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, an electrode tab extending from the positive electrode or the negative electrode of the stacked body, and an electrode lead coupled with the electrode tab, wherein the electrode tabs are formed with a pre-welding portion connecting respective electrode tabs and a main welding portion coupling the electrode tab and the electrode lead, wherein the pre-welding portion includes an inner side edge and an outer side edge, wherein at least one of the welding spots of the main welding portion overlaps an inner side edge of the pre-welding portion, and wherein an inner side edge of the pre-welding portion is disposed closer to the stacked body than an outer side edge of the pre-welding portion in the longitudinal direction of the electrode.