Square Battery Tab-to-Pole Welding Without Connection Sheets
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Solution Overview
Problem
The existing connection methods for square batteries, which use auxiliary welding sheets and connection sheets, increase the weight and reduce the internal space utilization and mass specific energy of the battery, leading to energy loss and a risk of thermal runaway during long-term use.
Innovation Solution
A square battery design where the tab of the core is directly connected to the cover plate via laser welding, eliminating the need for auxiliary and connection sheets, and utilizing ultrasonic pre-welding to improve the firmness and efficiency of the connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary welding sheet and connection sheet are used to connect core and cover plate, then connection reliability is improved, but battery weight increases and internal space utilization decreases
Solution Approach 1:
The patent removes the auxiliary welding sheet and connection sheet from the battery structure, achieving direct welding between the core tab and cover plate pole. This extraction of unnecessary components reduces battery weight while maintaining connection reliability through direct metal-to-metal welding.
Solution Approach 2:
The patent merges the functions of the auxiliary welding sheet, connection sheet, and tab into a single integrated structure where the tab is directly welded to the pole. This consolidation eliminates intermediate components and reduces overall weight while improving electrical conductivity.
2Reliability
If auxiliary welding sheet and connection sheet are used to connect core and cover plate, then connection reliability is improved, but internal space utilization rate decreases
Solution Approach 1:
The patent extracts and removes the auxiliary welding sheet and connection sheet from the battery internal structure. This elimination of intermediate components frees up internal space that was previously occupied by these sheets, improving space utilization rate while maintaining reliable connections through direct welding.
3Reliability
If auxiliary welding sheet and connection sheet are used for energy transmission, then connection stability is improved, but energy loss increases and temperature rises
Solution Approach 1:
The patent removes the auxiliary welding sheet and connection sheet that caused energy loss through multiple interfaces. By achieving direct welding between the tab and pole, the number of contact interfaces is reduced, minimizing resistance and energy loss while maintaining connection stability.
Solution Approach 2:
The patent merges the energy transmission path into a single direct weld joint, eliminating the multi-layer structure of auxiliary sheet-connection sheet-tab-pole. This streamlined path reduces interfacial resistance and energy loss, lowering operating temperature while maintaining stable energy transmission.
4Device complexity
If direct laser welding is used to connect tab and pole, then manufacturing simplicity is improved, but welding precision requirements increase
Solution Approach 1:
The patent employs ultrasonic pre-welding before laser welding to preliminarily position and bond the tab to the pole. This preliminary action creates a stable base that facilitates subsequent laser welding, reducing precision requirements for the final laser welding step while maintaining overall manufacturing simplicity.
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 enhances internal space utilization, mass specific energy, and reduces the risk of thermal runaway by creating a direct energy transmission path, improving the firmness of the weld and reducing energy loss.
Implementation Method 1
the tab is connected directly to the pole through laser welding
Implementation Method 2
perform ultrasonic pre-welding for a tab of a core according to a first solder printing area to form the ultrasonic pre-welded tab
Data Source
AI summary
The present disclosure provides a square battery and a welding method. The square battery includes: a cover plate provided with a pole; and a core provided with a tab, where the tab is directly connected to the pole by laser welding, so that construction of an energy transmission path of the battery is realized, and a charging and discharging function of the core is realized. Additionally, since the tab of the core of the square battery is directly connected to the cover plate of the square battery, an auxiliary welding sheet and a connection sheet are removed, thereby improving the internal space utilization rate and the mass specific energy of the square battery.