Battery Pneumatically Actuated Switch for Overpressure Safety
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Solution Overview
Problem
Lithium-ion batteries with prismatic metal housings face safety risks due to potential overcharging, which can lead to decomposition of the electrolyte, gassing, and explosive combustion, necessitating effective safety measures to prevent damage and ensure consumer safety.
Innovation Solution
A battery with a pneumatically actuable electrical switch that changes its state from 'closed' to 'open' when internal pressure exceeds a threshold, disconnecting the pole bolts from the electrodes, utilizing a bistable spring element and a gas-impermeable membrane to detect and transmit pressure, ensuring safe disconnection and preventing further electrical connection upon pressure normalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pneumatically actuated switch is used to disconnect electrical connections upon pressure increase, then safety is improved, but device complexity increases
Solution Approach 1:
The patent combines the pressure-sensing function and the electrical switching function into a single integrated component. The bistable spring element serves both as the pressure-responsive actuator and as the electrical contact mechanism, eliminating the need for separate pressure sensors and switches. This merging reduces overall device complexity while maintaining the safety function.
Solution Approach 2:
The bistable spring element automatically responds to pressure changes by transitioning between closed and open states without requiring external control systems. The element self-actuates based on the pressure differential across the membrane, providing autonomous safety protection. This self-service mechanism eliminates complex control electronics and simplifies the overall system.
2Measurement precision
If a bistable spring element with membrane is used to detect pressure, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The gas-impermeable membrane acts as an intermediary that transmits pressure information from the battery interior to the bistable spring element. The membrane converts internal pressure changes into mechanical displacement of the spring element, enabling precise pressure detection without direct exposure of the switching mechanism to the battery environment. This intermediary approach simplifies the overall structure while maintaining detection precision.
Solution Approach 2:
The bistable spring element detects pressure changes by transitioning between two stable mechanical states (compressed and extended positions). This parameter change from one stable state to another provides clear, discrete pressure threshold detection. The element's mechanical state change directly correlates with pressure levels, providing precise measurement without complex sensing electronics.
3Ease of operation
If the switch automatically returns to closed state upon pressure normalization, then ease of operation is improved, but reliability may worsen due to potential repeated activation
Solution Approach 1:
The bistable spring element provides periodic action by automatically transitioning between open and closed states based on pressure conditions. When pressure exceeds the threshold, the element switches to the open state; when pressure normalizes, it returns to the closed state. This periodic on-off action ensures the safety mechanism responds dynamically to changing conditions without requiring manual intervention, balancing ease of operation with reliable safety protection.
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 provides a reliable and simple safety mechanism that effectively disconnects electrical connections upon increased pressure, preventing further damage and ensuring safety by automatically returning to the closed state once pressure returns to normal, thus mitigating the risks associated with overcharging and potential combustion.
Implementation Method 1
when internal pressure exceeds a threshold
Implementation Method 2
a gas-impermeable membrane to detect and transmit pressure
Implementation Method 3
utilizing a bistable spring element
Implementation Method 4
a bistable, electrically conductive connecting element that connects the two contact elements in a first switching state and can be switched to a second switching state by a pressure increase
Implementation Method 5
disconnecting the pole bolts from the electrodes
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
A battery (100) is described, comprising a housing, at least one single cell with at least one positive and at least one negative electrode arranged in an interior space within the housing, a positive terminal bolt (103) passing through a wall (101) of the housing and electrically connected to the at least one positive electrode, and/or a negative terminal bolt passing through a wall of the housing and electrically connected to the at least one negative electrode, and at least one pneumatically actuated electrical switch which, upon a pressure increase occurring in the interior space of the housing exceeding a pressure threshold, changes its switching state from "closed" to "open" and thereby interrupts the electrical connection between at least one of the terminal bolts and the at least one electrode connected thereto.The switch comprises an electrically conductive spring element (106; 206) designed in the form of a cup, and a diaphragm (105) with the help of which the increasing pressure can be detected and transferred to the spring element (106; 206).