Divided Electrode Tab Safety Device for Pouch Battery
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Solution Overview
Problem
Conventional pouch type lithium ion secondary batteries for vehicles lack physical strength and cell-level safety devices, making it difficult to achieve high energy storage capacity while ensuring safety, as they are prone to thermal runaway and abnormal voltage issues during overcharging.
Innovation Solution
A high voltage battery design featuring a pouch type current interruptive device (CID) with a divided electrode tab and a cushion mechanism that separates and locks extensions to physically open the circuit when internal pressure exceeds a reference level, providing cell-level safety and preventing overcharge-induced reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a pouch type battery structure is used to increase energy storage capacity, then the energy density and energy storage capacity are improved, but the physical strength of the sheath is insufficient and cell-level safety cannot be ensured
Solution Approach 1:
The electrode tab is divided into a first part and a second part that can be separated from each other. The first part is connected to the positive electrode and the second part is connected to the negative electrode. This segmentation allows the battery to maintain high energy density while incorporating a safety mechanism that can physically separate the electrodes to prevent thermal runaway.
Solution Approach 2:
A current interruptive device (CID) is introduced as an intermediary component between the electrodes. The CID includes a first extension part and a second extension part that can be separated to interrupt current flow. This intermediary mechanism provides cell-level safety without compromising the pouch battery's energy storage capacity.
2Device complexity
If no cell level safety device is provided to maintain simple structure, then the device complexity is reduced, but the battery is prone to thermal runaway and abnormal voltage issues during overcharging
Solution Approach 1:
The safety function is merged with the existing electrode tab structure. The first and second extension parts of the electrode tab are integrated into the battery's current collection system, allowing the safety mechanism to perform both its protective function and electrical connection function, thereby maintaining structural simplicity while ensuring reliability.
Solution Approach 2:
The battery structure itself provides safety through the separable electrode tab design. When abnormal conditions occur such as overcharging or thermal runaway, the first and second extension parts automatically separate to interrupt current flow, making the system self-protecting without requiring external safety devices.
3Reliability
If a separable electrode tab structure with cushion is added to achieve cell-level safety, then the safety and reliability are improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
A cushion made of flexible material is placed between the first and second extension parts. This cushion allows for easy assembly and disassembly during manufacturing while providing the necessary mechanical force to separate the extension parts when safety conditions are triggered. The flexible nature of the cushion simplifies the manufacturing process compared to rigid mechanical components.
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 realizes cell-level safety and pack voltage safety by interrupting external current and preventing abnormal cell reactions, enhancing the safety and marketability of vehicle batteries.
Implementation Method 1
A cushion is inserted in the housing and compresses the first part extension and the second part extension such that the first part extension and the second part extension come into close contact with each other
Implementation Method 2
When an internal pressure of the pouch is increased higher than an internal pressure of the cushion, the first part extension and the second part extension may be separated from each other
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 pouch packages the battery cell therein. A housing is packaged in an interior of the pouch together with the battery cell and has an opening. A first part extension and a second part extension extend from the first part and the second part, respectively, that are inserted into the housing through the opening, and that come into contact with each other in the housing. A cushion is inserted in the housing and compresses the first part extension and the second part extension such that the first part extension and the second part extension come into close contact with each other.