Pouch Battery Electrode Lead Cutoff Using Shape Memory Alloy
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Solution Overview
Problem
Pouch-type batteries face safety issues due to excessive heat generation leading to thermal runaway, necessitating a mechanism to interrupt current flow and ensure user safety.
Innovation Solution
A protective member made of shape memory alloy (SMA) is positioned on the electrode lead, which expands or contracts based on temperature to physically interrupt current flow by forming a cutting line on the electrode lead when excessive heat is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective member is added to interrupt current flow, then safety is improved, but device complexity increases
Solution Approach 1:
The protective member utilizes temperature parameter changes to trigger its protective function. When the electrode lead temperature reaches a specific threshold, the protective member's physical properties change (expansion, phase transition, or resistance increase), automatically interrupting current flow without requiring external control systems or complex circuitry.
Solution Approach 2:
The protective member operates autonomously based on temperature conditions, eliminating the need for external monitoring systems, control circuits, or manual intervention. The member self-activates when thermal conditions indicate danger, providing a simple yet effective safety mechanism that doesn't add significant complexity to the battery cell structure.
2Reliability
If the protective member responds quickly to temperature changes, then safety is improved, but manufacturing precision requirements increase
Solution Approach 1:
The protective member employs phase transition phenomena (such as melting, vaporization, or structural transformation) at specific temperatures to rapidly change its electrical properties. This phase transition occurs naturally and predictably at well-defined temperature thresholds, providing quick response times without requiring complex manufacturing tolerances or precision control systems.
Solution Approach 2:
The protective member utilizes thermal expansion characteristics where dimensional changes occur predictably with temperature increases. This physical phenomenon provides a straightforward, temperature-dependent mechanism for triggering protective action that relies on natural material properties rather than precision-engineered components requiring tight manufacturing tolerances.
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 SMA-based protective member effectively interrupts current flow at high temperatures, enhancing safety by preventing thermal runaway and maintaining normal operation of non-defective cells within a battery module.
Implementation Method 1
the protective member is made of a shape memory alloy (SMA) and is reduced at a first temperature
Data Source
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AI summary
A battery cell according to one embodiment of the present disclosure includes a battery case that has an electrode assembly mounted therein and includes a sealing part having a structure in which the outer peripheral side is sealed by heat fusion; an electrode lead that is electrically connected to the electrode tab included in the electrode assembly and protrudes outward from the battery case via the sealing part; a lead film that is located between the electrode lead and the sealing part; and a protective member in contact with at least a part of an outer surface of the electrode lead, wherein the size of the protective member differs depending on the temperature of the electrode lead.