Rotating Cover Switch for Battery Swelling Safety
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Solution Overview
Problem
Secondary battery packs face safety risks due to potential ignition from internal short circuits caused by swelling during overcharge, which existing technologies fail to adequately prevent.
Innovation Solution
A secondary battery pack design featuring a Power Relay Assembly (PRA) and Battery Management System (BMS) with a rotating cover and switch mechanism that shuts off power to the cells when swelling occurs, preventing overcharge-induced short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a secondary battery pack uses a pouch-type battery cell with high integration degree, then the battery pack achieves smaller size and weight, but the battery pack becomes vulnerable to swelling and internal short circuits during overcharge
Solution Approach 1:
A switch mechanism is introduced as an intermediary component between the battery cells and the power source. The switch includes a movable contact that can be displaced by swelling pressure to open the circuit, preventing current flow. This intermediary device allows the lightweight pouch battery design to maintain safety by automatically interrupting power when swelling occurs.
Solution Approach 2:
The battery pack design enables self-protection through the swelling-actuated switch mechanism. When the battery cells swell due to overcharge, the swelling pressure automatically displaces the movable contact to open the circuit, shutting off power without requiring external intervention. This self-service mechanism prevents internal short circuits and ignition while maintaining the lightweight pouch battery configuration.
2Device complexity
If a battery pack lacks an automatic shutdown mechanism, then the device complexity is reduced, but the battery pack cannot prevent ignition from internal short circuits during overcharge
Solution Approach 1:
The patent replaces complex electronic monitoring and control systems with a simple mechanical switch mechanism. The movable contact is directly actuated by swelling pressure from the battery cells, using mechanical force to open the circuit. This mechanical substitution achieves automatic shutdown functionality with minimal complexity, avoiding the need for sophisticated sensors, microcontrollers, or power electronics while effectively preventing ignition from short circuits.
3Reliability
If a switch mechanism is added to shut off power during swelling, then safety is improved, but the device complexity increases
Solution Approach 1:
The switch mechanism serves multiple functions simultaneously: it acts as a circuit interrupter to prevent short circuits, a pressure sensor to detect swelling, and a shutdown actuator. The movable contact is positioned to be directly actuated by swelling pressure from the battery cells, combining detection and response functions in a single component. This multi-functionality minimizes the number of separate components needed, reducing overall device complexity while maintaining high safety performance.
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
Effectively prevents ignition by interrupting power supply to the secondary battery cells during swelling, ensuring safety by automatically switching off charging power when swelling is detected.
Implementation Method 1
one side and the other side in the horizontal direction of the cover are capable of rotating up and down around the support member as a rotation axis
Data Source
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AI summary
Provided is a secondary battery pack including a plurality of secondary battery modules including a plurality of secondary battery cells stacked in parallel to each other in a vertical direction, a cover for covering an uppermost surface of the secondary battery cells and with one side and the other side in a horizontal direction being rotatable around a central portion in a horizontal direction as a rotation axis, and a switch installed at an upper side of the one end in the horizontal direction of the cover, a housing for accommodating the secondary battery modules therein, a PRA including a relay electrically connected to the secondary battery cells and switches, for transmitting charging power supplied from the outside to the secondary battery cells when the relay is in a close state and changing the relay to an open state when the switch is pushed according to pressure applied to an upper side from a lower surface of the cover, and a BMS for controlling the PRA.