Elastic Tab Current Interrupter for Vehicle Battery Safety
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Solution Overview
Problem
Conventional pouch type lithium ion secondary batteries for vehicles lack a cell-level safety device, leading to safety concerns such as thermal runaway and abnormal voltage induction during overcharging, which compromises driving safety and energy storage capacity.
Innovation Solution
A high voltage battery design incorporating a pouch type current interruptive device (CID) with an electrode tab divided into two parts, where a first part extension is fixed to a lower pouch and a second part extension with elasticity is fixed to an upper pouch, featuring a hook part and elastic legs to physically open the circuit when abnormal cell expansion occurs, thereby interrupting external electric current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a pouch type lithium ion secondary battery is designed with high energy storage capacity, then the energy density and energy storage capacity increase, but the battery lacks cell-level safety devices and physical strength, making it vulnerable to thermal runaway and abnormal voltage induction
Solution Approach 1:
The electrode tab is segmented into two separate parts: a first part fixed to the lower pouch and a second part fixed to the upper pouch. These parts are connected through elastic legs that can be elastically deformed and separated when abnormal expansion occurs, enabling cell-level safety interruption without compromising the high energy storage capacity design
Solution Approach 2:
Elastic legs serve as an intermediary mechanism between the upper and lower pouches. Under normal conditions, they maintain electrical connection through contact. When abnormal expansion occurs, they elastically deform and separate, physically opening the circuit and interrupting current flow, thus providing safety without affecting the battery's energy storage function
2Device complexity
If the battery operates without a cell level safety device, then the device complexity is reduced, but thermal runaway and abnormal voltage induction can occur during overcharging, compromising driving safety
Solution Approach 1:
The battery structure itself provides safety functionality through the elastic legs and two-part electrode tab design. When abnormal expansion occurs, the elastic legs automatically deform and separate, causing the electrode tab to physically open and interrupt the circuit. This self-activating mechanism provides cell-level safety without requiring external safety devices or increasing overall structural complexity
Solution Approach 2:
The elastic legs are designed with specific elastic properties that allow them to maintain contact under normal operating conditions but deform and separate when subjected to abnormal expansion forces. This parameter-based design enables the safety mechanism to activate only when needed, maintaining simplicity while preventing thermal runaway
3Reliability
If the electrode tab is divided into two parts with elastic legs, then cell-level safety is achieved through physical circuit opening, but the device complexity increases
Solution Approach 1:
The safety mechanism is merged with the existing electrode tab structure rather than being added as a separate component. The elastic legs and two-part tab design integrate the safety function into the current collection system, achieving cell-level safety while minimizing increases in overall device complexity
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 realizes cell-level safety and pack voltage safety by interrupting the circuit at a predetermined pressure level, preventing overcharge and abnormal reactions within individual cells, enhancing safety and marketability of vehicle batteries.
Implementation Method 1
a second part extension extends from the second part, comes into contact with the first part extension, has elasticity, and is fixed at an upper end thereof to an upper pouch
Data Source
AI summary
A high voltage battery for vehicles includes an electrode tab that is divided into a first part placed near a battery cell, and a second part placed near a terminal. A first part extension extends from the first part and is fixed to a lower pouch. A second part extension extends from the second part, comes into contact with the first part extension, has elasticity, and is fixed at an upper end thereof to an upper pouch. A hook part extends from the first part extension and holds the second part extension by grasping an edge of the second part extension.