Battery Cell Venting With Meltable Adhesive Film
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Solution Overview
Problem
Current battery cells with steel-shell designs require large valve spaces for pressure relief, compromising safety and increasing manufacturing costs due to laser notching, which also has low thermal sensitivity.
Innovation Solution
A battery cell design featuring a housing with through-holes and a pressure relief mechanism using an adhesive film that melts at a threshold temperature to release pressure, integrated with a channel on an insulator for efficient pressure relief, reducing the need for additional space and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laser notch is created on the steel shell cover for pressure relief, then pressure relief function is achieved, but thermal sensitivity is poor and manufacturing cost increases
Solution Approach 1:
The patent replaces the mechanical laser notching process with a thermal-mechanical pressure relief mechanism. Instead of using laser energy to create a permanent notch, the invention uses a cap with a through-hole that is sealed by an adhesive film. The adhesive film is designed to melt at a specific temperature threshold, automatically opening the pressure relief path without requiring laser processing. This substitution eliminates the high manufacturing cost and poor thermal sensitivity associated with laser notching.
Solution Approach 2:
The patent changes the physical state of the adhesive film from solid to liquid by changing temperature parameters. The adhesive film is selected to have a melting point below the battery's maximum operating temperature but above normal operating conditions. When the battery temperature reaches the threshold, the adhesive film melts and flows through the through-hole, creating an automatic temperature-responsive pressure relief mechanism with high thermal sensitivity.
2Reliability
If a laser notch is created on the steel shell cover, then pressure relief is achieved, but the valve space is large and space utilization decreases
Solution Approach 1:
The patent implements nesting by placing the pressure relief mechanism inside the existing electrode post structure. The cap with the through-hole is positioned at the end of the electrode post, and the adhesive film seals this through-hole. This nested design allows the pressure relief function to be integrated within the existing battery structure without requiring additional external valve space, thereby improving space utilization while maintaining pressure relief reliability.
Solution Approach 2:
The electrode post serves multiple functions: it provides electrical connection, structural support, and now also houses the pressure relief mechanism. By integrating the pressure relief function into the electrode post structure, the patent eliminates the need for separate valve components and reduces the overall space required for pressure relief operations.
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 design enhances safety and reliability of pressure relief, reduces space occupation, and lowers manufacturing costs by using a thermally sensitive adhesive film to create a compact structure.
Implementation Method 1
the adhesive film is able to melt when a temperature of the battery cell reaches a threshold, so as to release pressure inside the housing through the second through-hole
Data Source
AI summary
A battery cell includes a housing, an electrode post, and a pressure relief mechanism. The housing includes a bottom wall and a plurality of sidewalls disposed around the bottom wall. A first through-hole and a second through-hole are created on a first sidewall of the plurality of sidewalls. The electrode post is threaded through the first through-hole. A pressure relief mechanism covers the second through-hole. The pressure relief mechanism includes a adhesive film. The adhesive film is able to melt when a temperature of the battery cell reaches a threshold, so as to release pressure inside the housing through the second through-hole.