Dummy Electrode Short Circuit for Battery Thermal Runaway Prevention
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Solution Overview
Problem
Conventional electrochemical devices, such as lithium-ion batteries, are prone to explosion and ignition due to internal pressure buildup and thermal runaway, which existing safety valves do not always effectively mitigate, leading to potential explosions or ignitions.
Innovation Solution
The introduction of a multilayer structure with dummy electrodes and resistance control layers, where the dummy electrodes are electrically connected to the main electrodes and have a resistance value that allows for a controlled internal short circuit at a lower temperature than the main electrodes, preventing thermal runaway and explosion by generating a moderate self-discharge and shifting active materials to more thermostable regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If safety valves are installed to release gases when internal pressure rises, then gas release function is improved, but the device still risks thermal runaway and explosion because safety valves do not prevent internal short circuits before they occur
Solution Approach 1:
The dummy electrodes are designed to short-circuit at a lower temperature than the main electrodes, performing a preliminary protective action before thermal runaway occurs. This preliminary short circuit diverts current and prevents the main electrodes from reaching dangerous temperatures, thereby preventing explosion without requiring complex safety valves
Solution Approach 2:
The invention converts the harmful effect of internal short circuits into a beneficial protective mechanism. By designing dummy electrodes that short-circuit first at lower temperatures, the harmful short circuit phenomenon is harnessed to protect the main electrodes from thermal runaway, transforming a potential failure mode into a safety feature
2Reliability
If dummy electrodes with resistance control layers are added to enable controlled short circuits, then safety is improved, but device complexity increases
Solution Approach 1:
The resistance control layers on the dummy electrodes have specifically engineered resistance values that enable them to short-circuit at lower temperatures than the main electrodes. By changing the resistance parameter of the dummy electrodes, the invention creates a temperature-dependent protection mechanism that activates before thermal runaway occurs, improving safety without requiring complex control systems
Solution Approach 2:
The dummy electrodes are constructed with composite structures including resistance control layers combined with conductive materials. This composite design enables the dummy electrodes to exhibit specific electrical and thermal properties that allow them to short-circuit preferentially at lower temperatures, providing safety protection while maintaining structural integration
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
This design significantly enhances the safety of electrochemical devices by preventing explosions and ignitions through controlled internal short circuits, thereby improving safety in high-temperature environments.
Implementation Method 1
the resistance control layer has a resistance value as a total resistance value of the first and second dummy electrodes falling in such a range that an estimated internal short circuit current between the first and second dummy electrodes is equivalent to 0.09 C to 1.00 C
Implementation Method 2
the first and second dummy electrodes have respective opposing parts opposing each other through a second separator at an outer peripheral part of the electrode matrix
Data Source
AI summary
An electrochemical device comprises an electrode matrix including a multilayer structure composed of a positive electrode, a negative electrode, and a first separator, and first and second dummy electrodes electrically connected to the positive and negative electrodes, respectively. The first and second dummy electrodes have respective opposing parts opposing each other through a second separator at an outer peripheral part of the electrode matrix. One or each of the first and second dummy electrodes has a resistance control layer at least on a side where the opposing parts oppose each other. The resistance control layer has such a resistance value that an estimated internal short circuit current between the first and second dummy electrodes is equivalent to 0.09 C to 1.00 C. The first and second dummy electrodes are adapted to short-circuit each other at a lower temperature than the positive and negative electrodes do.