Battery Terminal Connection Plate with Intermetallic Bonding
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Solution Overview
Problem
The connection structure of lithium secondary cells is prone to detachment due to thermal expansion, causing the inner diameter of the Al member's hole to exceed the outer diameter of the annular Cu member, leading to potential disconnection.
Innovation Solution
A connection plate with a plate-like base featuring a first hole for a first metal battery terminal and a second hole for a second metal terminal, incorporating a flange portion and a multi-layered battery terminal connection portion made of different metals to enhance bonding and prevent detachment, with an intermetallic compound layer formed to improve bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an annular Cu member is arranged on the inner peripheral surface of the hole of the Al member by interference fit, then the bonding strength between Cu member and Al member is improved, but thermal expansion causes the inner diameter of the Al member's hole to become larger than the outer diameter of the Cu member, leading to detachment
Solution Approach 1:
A connection plate made of Cu is introduced as an intermediary component between the Al member and the Cu member. The connection plate includes a fitting portion that fits into the hole of the Al member and a connection portion that connects to the Cu member. This intermediary Cu connection plate prevents direct thermal expansion conflicts between Al and Cu, as the Cu connection plate expands with the Cu member while providing a stable interface with the Al member, thereby preventing detachment while maintaining bonding strength.
2Reliability
If different metals (Al and Cu) are directly bonded together, then the electrical conductivity is improved, but galvanic corrosion and metal reaction occur at the bonding interface
Solution Approach 1:
The connection plate made of Cu serves as a mediator between the Al member and the Cu member, preventing direct contact between dissimilar metals. This eliminates the galvanic corrosion issue while maintaining excellent electrical conductivity through the Cu connection plate, which has high electrical conductivity and is compatible with both Al and Cu components.
3Strength
If a multi-layered structure with flange portion is used to prevent detachment, then the bonding strength is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The connection plate integrates multiple functions into a single component: the fitting portion for connecting to the Al member, the connection portion for bonding to the Cu member, and the flange portion for preventing detachment. By merging these functions into one Cu piece rather than using separate components, the overall assembly is simplified while maintaining strong bonding and preventing detachment.
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 inhibits detachment of the battery terminal connection portion from the base by reducing electric resistance and preventing reaction between metals, while also enhancing corrosion resistance and facilitating easy manufacturing and laser welding.
Implementation Method 1
the flange portion can be retained on at least one of the upper surface and the lower surface of the base, and hence detachment of the battery terminal connection portion from the base can be inhibited
Implementation Method 2
an intermetallic compound layer containing alloy made of the first metal constituting the base and the third metal constituting the second layer is formed on an interface between the base and the second layer of the battery terminal connection portion
Implementation Method 3
the first battery terminal and the base, both of which are made of the identical first metal, can be bonded to each other, and the second battery terminal and the first layer of the battery terminal connection portion, both of which are made of the identical second metal, can be bonded to each other
Data Source
AI summary
A connection plate for battery terminals capable of inhibiting a base and a battery terminal connection portion from being detached from each other is provided. This connection plate for battery terminals (2) includes a battery terminal connection portion (4) fitted into a second hole (31) of a base (3) made of first metal, including a hole for connection (42) into which a second battery terminal (1b) is inserted and a flange portion (4b), while the battery terminal connection portion is constituted by at least a first layer (40) made of second metal, arranged on a side opposite to the base and a second layer (41) made of third metal, arranged between the base and the first layer.