Thermal Interlock for Battery Pack Using Heat-Sensitive Polymer
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Solution Overview
Problem
Existing methods for detecting faulty batteries in electric vehicles are slow and insensitive, posing a significant danger due to the potential for high heat generation and explosion, especially since hundreds of battery cells are involved, and current smoke detection technologies are inadequate.
Innovation Solution
A heat-triggered electricity halt system using a sensing member with heat-sensitive materials and polymers that electrically isolate and reconnect conductive wires in response to excessive heat, allowing for rapid detection and disconnection of faulty batteries, incorporating heat-sensitive members that change conductivity in response to temperature thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If smoke detectors are used to detect faulty batteries, then the detection system is simple to implement, but the response time is slow and sensitivity is low
Solution Approach 1:
The patent replaces the mechanical/optical smoke detection system with an electrical sensing system. The sensing member with heat-sensitive materials and polymer insulation detects thermal changes through electrical resistance variations, substituting the slow optical smoke detection with rapid electrical measurement that responds directly to temperature changes at the battery cell level.
Solution Approach 2:
The patent introduces a polymer material as an intermediary between the conductive wires and the heat source. This polymer serves as a thermal conductor that transfers heat from the faulty battery to the sensing member, while also providing electrical insulation. The intermediary enables sensitive thermal detection without direct electrical contact with the battery, achieving high sensitivity without increased system complexity.
2Speed
If thermal sensing members with polymers are used to detect faulty batteries, then the response time and sensitivity are improved, but the device structure becomes more complex
Solution Approach 1:
The patent merges multiple functions into a single sensing member structure. The polymer-insulated conductive wires simultaneously provide electrical conduction, thermal sensing, and electrical insulation functions. The heat-sensitive material integrated within the polymer matrix combines thermal detection with structural support, achieving rapid response without requiring separate components for each function.
Solution Approach 2:
The sensing member utilizes composite materials combining conductive wires, polymer insulation, and heat-sensitive materials. This composite structure integrates thermal conductivity, electrical insulation, and temperature-dependent resistance properties into a single element, enabling rapid thermal response while maintaining structural integrity and electrical safety without increasing overall device complexity.
3Measurement precision
If heat-sensitive materials are used to rapidly detect temperature changes, then the detection accuracy is improved, but the system complexity increases due to multiple components
Solution Approach 1:
The heat-sensitive material within the sensing member provides self-service by automatically changing its electrical resistance in response to temperature changes. This intrinsic property eliminates the need for external temperature sensors, amplifiers, or complex signal processing circuits. The sensing member self-generates the detection signal through its temperature-dependent resistance, achieving high detection accuracy with minimal additional system components.
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
Enables quick and reliable detection of faulty batteries, preventing malfunctions and explosions by rapidly disconnecting faulty cells from the power supply, thereby ensuring safety and preventing damage to neighboring cells.
Implementation Method 1
the polymer electrically isolates the first and the second electrically conductive wires from each other
Implementation Method 2
the polymer is fabricated to melt when exposed to heat at the predetermined threshold, thereby electrically coupling the first and second wires
Implementation Method 3
the at least one heat sensitive members is in thermal contact with a battery
Implementation Method 4
having a heat-dependent conductivity... the conductivity comprises electrical conductivity
Implementation Method 5
the PTC material is capable of changing a value of electrical conductivity when exposed to heat above the predetermined threshold
Implementation Method 6
the NTC material is capable of changing a value of electrical conductivity in response to a fault occurring in the battery
Data Source
AI summary
Faulty battery detecting and locating devices and methods are able to detect and locate a faulty battery cell. The device applies an energy to a sensing member, such as a polymeric tube containing at least two polymer-coated and twisted electric wires. Heat that is generated by a faulty battery triggers an electric communication between the two electric wires by melting at least a portion of the polymer. The resulting change in resistance between the two electric wires is used to detect and locate a faulty battery.