Battery Cutting Unit in Seating Groove for Safety
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to potential ignition or explosion in abnormal operation states like over-charging, over-discharging, or high temperatures, which existing safety mechanisms like fuses and BMS struggle to manage effectively, especially in large battery packs where pressure increases rapidly, and previous solutions like rupture mechanisms can damage the battery case during assembly or in normal operation.
Innovation Solution
A battery design featuring a cutting unit integrated into a seating groove within the battery module case, where the cutting unit is positioned to avoid contact with the sub battery module in normal operation but can engage and cut the pouch in abnormal states, preventing ignition or explosion by maintaining stability and manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rupture mechanism is formed in the space where the secondary battery is received, then gas discharge capability is improved, but the case may be damaged during assembly or in normal operation due to vibration
Solution Approach 1:
The patent introduces a pouch as an intermediary element between the cutting unit and the battery cell. The pouch serves as a sacrificial component that can be cut by the cutting unit to release gas, while the case structure remains intact. This mediator approach allows the safety function to be achieved without directly compromising the case structure during normal operation or assembly.
Solution Approach 2:
The patent divides the safety mechanism into separate functional components: the cutting unit integrated into the case, the pouch containing the battery cell, and the gas discharge path. By segmenting the system, the cutting unit can be positioned in a seating groove without directly contacting the battery cell during assembly, preventing damage while maintaining the ability to cut the pouch in emergency situations.
2Reliability
If the cutting unit is positioned to contact the pouch in normal operation, then gas discharge is enabled, but the battery operation stability deteriorates due to unnecessary contact
Solution Approach 1:
The patent creates a dynamic safety mechanism where the cutting unit's interaction with the pouch is conditional rather than static. During normal operation, the pouch remains intact and the cutting unit does not contact it. Only when the pouch expands abnormally does it contact the cutting unit, triggering the gas discharge function. This dynamic approach ensures stability during normal operation while maintaining safety capability.
Solution Approach 2:
The cutting unit is pre-positioned in the seating groove during manufacturing, ready to act if needed. The pouch is designed with sufficient initial strength to resist the cutting unit during normal operation. This preliminary configuration allows the system to maintain stability during normal use while being prepared for emergency gas discharge when the pouch abnormally expands and contacts the cutting unit.
3Measurement precision
If traditional safety mechanisms (fuse, bimetal, BMS) are used, then electrical fault detection is improved, but sufficient safety cannot be secured when BMS fails to operate
Solution Approach 1:
The patent implements a passive safety mechanism that does not require external control systems like BMS to function. The cutting unit automatically activates when the pouch abnormally expands and contacts it, triggering gas discharge without needing electrical sensing or control. This self-service approach provides a backup safety layer that operates independently of electronic control systems, ensuring safety even when BMS fails.
Solution Approach 2:
The patent converts the harmful effect of pouch expansion during abnormal operation into a beneficial safety trigger. When the pouch abnormally expands due to overheating or other failures, this expansion itself becomes the signal to activate the cutting unit and initiate gas discharge. The harmful symptom (pouch expansion) is transformed into the activation mechanism for the safety response.
Data Source
AI summary
Provided is a battery, and more particularly, a battery in which a cutting unit is formed in a seating groove so that the cutting unit and a sub battery module do not contact each other in a normal operation state, such that the battery may be stably driven, and a pouch of the sub battery module may be cut by the cutting unit only in an abnormal operation state such as over-charging, over-discharging, exposure to a high temperature, an electric short circuit, or the like, to prevent ignition or explosion in advance, such that safety may be improved.