Battery Pack Terminal Solder-Bonding to Prevent Welding Heat Damage
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Solution Overview
Problem
The direct welding of a negative electrode lead plate to the negative electrode terminal in coin-type lithium batteries can cause damage due to heat during the welding process.
Innovation Solution
A battery pack configuration featuring a secondary battery with a metal exterior and a circuit board, where the connection portions on the circuit board are solder-bonded to the external terminals, allowing for effective joining of the output tab to either the positive or negative electrode terminal without direct welding, thereby preventing heat damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct welding is used to join the negative electrode lead plate to the negative electrode terminal, then electrical connection is achieved, but the battery may be damaged by heat during welding
Solution Approach 1:
The patent introduces a tab as an intermediary component between the negative electrode lead plate and the negative electrode terminal. This tab serves as a mediator that receives the lead plate through adhesive bonding (avoiding direct welding heat) and provides a soldering surface for electrical connection, thus protecting the battery from welding heat while maintaining electrical connectivity.
Solution Approach 2:
The patent segments the connection process into two distinct stages: first, adhesive bonding of the lead plate to the tab (avoiding heat); second, soldering of the terminal to the tab (controlled heat application only where needed). This segmentation separates the heat-generating welding step from the battery structure, protecting it from thermal damage.
2Strength
If solder-bonding is used to join the connection portion to the external terminal, then mechanical bonding strength is enhanced and thermal damage is minimized, but the joining process becomes more complex
Solution Approach 1:
The tab acts as an intermediary that provides a dedicated soldering surface, concentrating the complex soldering process at a specific location rather than requiring direct soldering between the terminal and battery components. This simplifies the overall process by localizing the complexity to a manageable interface.
Solution Approach 2:
The tab is pre-formed with a specific geometry that includes a soldering surface, preparing the connection interface in advance. This preliminary preparation of the connection geometry simplifies the subsequent soldering process and ensures proper bonding strength without requiring complex real-time adjustments.
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 configuration enhances mechanical bonding strength, reduces total resistance, minimizes thermal damage, and prevents short-circuiting, while allowing for a compact design and improved assembly efficiency.
Implementation Method 1
the connection portion having the first opening is solder-bonded to the first external terminal or the second external terminal
Data Source
AI summary
Disclosed is a battery pack including a secondary battery and a circuit board, in which the secondary battery includes a metal exterior portion, a first external terminal, and a second external terminal, the circuit board has a plurality of connection portions connected to the first external terminal or the second external terminal, at least one of the connection portions has a first opening, and the connection portion having the first opening is solder-bonded to the first external terminal or the second external terminal.