Battery Housing Heat Isolation Using a Frangible Bulb Switch
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Solution Overview
Problem
Lithium-ion batteries pose safety hazards due to their flammable electrolyte and potential for thermal runaway, which can lead to fires and are exacerbated by increased temperature, posing risks in critical functions.
Innovation Solution
A safety battery apparatus with a heat detection system that includes a frangible bulb and a biasing element, which isolates the electrical circuit or activates an alarm when a predetermined temperature is exceeded, and a fire suppression system with a heat-activated mechanical element that introduces fire suppressant material to prevent thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal expansion of liquid or gas in the frangible bulb is used to detect temperature, then temperature detection precision is improved, but device complexity increases due to the mechanical switch and biasing element mechanism
Solution Approach 1:
The frangible bulb contains liquid or gas that undergoes thermal expansion when temperature increases. This phase transition-based mechanism provides precise temperature detection by shattering the bulb at a predetermined temperature threshold, triggering the safety switch without requiring complex electronic sensors.
Solution Approach 2:
The patent replaces complex electronic temperature sensing and control systems with a simple mechanical thermal expansion mechanism. The frangible bulb's physical expansion and subsequent shattering directly actuates the switch through mechanical force, eliminating the need for electronic circuitry while maintaining detection precision.
2Reliability
If a frangible bulb with biasing element is used to isolate the electrical circuit, then safety reliability is improved, but device complexity increases due to the mechanical components
Solution Approach 1:
The biasing element is pre-loaded to exert force on the switch in the isolated position before any thermal event occurs. This preliminary anti-action ensures that when the frangible bulb shatters, the switch is already predisposed to move to the isolated position, providing immediate and reliable circuit disconnection without requiring complex control logic.
Solution Approach 2:
The mechanical system is designed to be self-actuating through thermal expansion. The frangible bulb's own thermal expansion provides the triggering force, and the biasing element's stored mechanical energy provides the actuating force, eliminating the need for external power sources, sensors, or control systems.
3Object-affected harmful factors
If the switch isolates the electrical circuit upon temperature threshold exceedance, then fire risk is reduced, but loss of time occurs during circuit isolation
Solution Approach 1:
The biasing element is pre-loaded to exert force on the switch in the isolated position before any thermal event occurs. This preliminary action ensures that when the frangible bulb shatters, the switch is already predisposed to move to the isolated position, providing immediate and reliable circuit disconnection without requiring complex control logic.
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 system effectively prevents thermal runaway and minimizes fire risk by isolating the electrical circuit and introducing fire suppressant, ensuring safer operation of lithium-ion batteries.
Implementation Method 1
a frangible bulb filled with a liquid or gas that is configured to shatter or break at a pre-determined temperature as a result of thermal expansion of the liquid or gas within the bulb
Implementation Method 2
a biasing element; the heat detection apparatus is operatively coupled to the electrical switch; the biasing element exerts a biasing force which urges the heat detection apparatus to configure the switch in its isolation configuration
Data Source
AI summary
A safety battery apparatus comprising a battery housing within which is located one or more rechargeable electrochemical cells, and a heat safety apparatus associated with the battery housing, wherein the heat safety apparatus includes a heat detection apparatus and an electrical switch that forms part of an electrical circuit to which the electrochemical cell(s) are connected and/or forms part of an alarm circuit; the heat detection apparatus comprises a frangible bulb filled with a liquid or gas that is configured to shatter or break at a pre-determined temperature as a result of thermal expansion of the liquid or gas within the bulb, and a biasing element; the heat detection apparatus is operatively coupled to the electrical switch; the switch has an isolation configuration in which the switch isolates the electrical circuit from the electrochemical cells and/or activates the alarm circuit if a pre-determined threshold temperature within the battery housing is exceeded; the biasing element exerts a biasing force which urges the heat detection apparatus to configure the switch in its isolation configuration; the frangible bulb exerts a counterbalance force against the biasing force; and wherein the counterbalance force is removed when the frangible bulb shatters or breaks.