Internal Battery Current Limiter and Interrupter for Separator Shorts
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Solution Overview
Problem
Lithium-ion batteries face safety hazards due to thermal runaway caused by internal short circuits and overcharging, leading to potential fires or explosions, as they lack effective mechanisms to limit internal discharge rates and interrupt electrical coupling in case of separator failures.
Innovation Solution
Incorporating a current limiter with resistive properties and a thermally or voltage-activatable current interrupter into the battery design, which forms an electrical coupling between electrodes and current collectors, diverting current and interrupting electrical paths when triggers are activated, thereby reducing the risk of thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is used to prevent internal discharge between electrodes, then battery safety is improved, but the separator is still subject to short circuit risks that can cause rapid internal discharge and thermal runaway
Solution Approach 1:
A current interrupter device is introduced as an intermediary component between the separator and the electrodes. This device includes a fusible element that melts at a predetermined temperature to open the circuit, preventing rapid internal discharge current from reaching dangerous levels even when the separator shorts out, thus adding a protective mediation layer against separator failure
Solution Approach 2:
The current interrupter is pre-configured with a fusible element designed to melt at a specific temperature threshold before thermal runaway occurs. This preliminary protective mechanism is already in place during normal battery operation, ready to activate automatically when abnormal temperature rise indicates separator short circuit, preventing the harmful effect before it can develop into thermal runaway
2Use of energy by moving object
If high energy density electrodes are used to increase energy storage capacity, then battery energy density is improved, but the risk of thermal runaway increases due to higher chemical energy content
Solution Approach 1:
The current interrupter serves as a safety mediator between the high energy density electrodes and the external environment. By monitoring temperature through the fusible element, it provides a protective barrier that can isolate the high-energy electrodes when abnormal conditions arise, preventing the chemical energy from being released in an uncontrolled thermal runaway event
Solution Approach 2:
The fusible element acts as a pre-prepared safety cushion against thermal runaway. Before the high energy density electrodes can cause catastrophic failure, the fusible element is ready to melt and open the circuit at a predetermined temperature, cushioning the system against the full force of potential thermal runaway by limiting current flow
3Power
If no internal current limiting mechanism is present to allow rapid discharge, then battery power output is improved, but internal short circuits can cause rapid joule heat generation leading to fire or explosion
Solution Approach 1:
The current interrupter with fusible element acts as an automatic current limiting intermediary. During normal operation, it allows full power output without restriction. When an internal short circuit causes abnormal temperature rise, the fusible element melts to open the circuit, automatically limiting the current and thereby controlling joule heat generation to prevent fire or explosion
Solution Approach 2:
The current interrupter provides self-service current limiting protection without requiring external control systems. The fusible element automatically responds to temperature rise caused by excessive current or short circuits by melting and opening the circuit, thereby self-regulating the current flow and limiting joule heat generation to safe levels
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 limits internal discharge rates and interrupts electrical coupling during separator failures, preventing thermal runaway and reducing the risk of fires or explosions by diverting current and forming nonconductive gaps, thus enhancing the safety and stability of lithium-ion batteries.
Implementation Method 1
a gas generating component for transitioning the current interrupter from the engaged to the unengaged configuration, the gas generating component having a trigger for generating a gas, the trigger being selected from the group consisting of temperature triggers and voltage triggers
Implementation Method 2
a current limiter forming an electrical coupling between one of the electrodes and its corresponding current collector, the current limiter having a resistivity for resistively impeding current therethrough and, in the event the separator forms the short circuit, for diverting current from the electrode current collector to which it is coupled
Implementation Method 3
the short circuit potentially allowing a rapid internal discharge between the two electrodes, the rapid internal discharge between the two electrodes potentially allowing a rapid production of joule heat therefrom
Data Source
Figure 1A~1G
Figure 2A~3B
Figure 4A~4D
AI summary
A high energy density rechargeable (HEDR) battery employs a current interrupter to prevent thermal runaway in the event of internal discharge or other disruption of the separator. The current interrupter is interior to the battery.