Conductive Hot Melt Adhesive for Battery Thermal Discharge
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Solution Overview
Problem
Existing battery technologies face challenges in preventing thermal runaway and associated fires or explosions, especially under high-load or high-temperature conditions, without compromising safety performance or increasing component count and cost.
Innovation Solution
A conductive hot melt adhesive with a Vicat softening temperature ranging from 60° C. to 130° C., composed of a matrix and conductive filler, is used between positive and negative electrode components, transitioning from a solid to a conductive state at elevated temperatures to facilitate quick discharge and reduce thermal risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an NTC component is added to the battery cell to improve safety performance, then the battery can discharge when abused in high temperature, but the battery suffers from slow discharge, capacity loss, increased component count and cost, reduced power density, and separator impedance surge
Solution Approach 1:
The patent combines the safety protection function with the existing adhesive material by incorporating conductive fillers (such as carbon black, graphite, or metal particles) into the adhesive matrix. This merging eliminates the need for separate NTC components while achieving thermal runaway protection through controlled short-circuiting at high temperatures.
Solution Approach 2:
The adhesive material serves multiple functions simultaneously: it provides mechanical bonding between battery components, electrical insulation under normal conditions, and thermal conduction for safety protection when temperature rises. This multi-functionality replaces the dedicated NTC component with a universal material that adapts its properties based on temperature.
2Reliability
If an NTC component is embedded in the separator to improve safety performance, then the battery can discharge when abused in high temperature, but the separator experiences impedance surge in normal temperature state, affecting C-rate and discharge performance
Solution Approach 1:
The conductive adhesive is applied locally at specific positions where thermal runaway short-circuiting is needed, rather than uniformly throughout the separator. This localized application ensures safety protection at critical points while maintaining the separator's insulation properties and low impedance in the bulk regions, thus preserving discharge performance.
Solution Approach 2:
The adhesive material undergoes a temperature-dependent parameter change: it remains electrically insulating at normal temperatures (maintaining low separator impedance) but becomes conductive at elevated temperatures (enabling safety discharge). This parameter change is achieved through the phase transition or resistance change of the conductive filler particles within the adhesive matrix.
3Reliability
If an NTC component is added to the battery cell to improve safety performance, then the battery can discharge when abused in high temperature, but the power density is affected due to occupied space inside the battery
Solution Approach 1:
The safety protection function is merged into the adhesive material that is already present in the battery structure. By making the adhesive conductive, the same material serves both as a structural adhesive and as a thermal safety device, eliminating the need for additional NTC components that would occupy valuable battery space and reduce power density.
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 conductive hot melt adhesive effectively prevents battery accidents by allowing safe discharge at high temperatures, enhancing safety performance without adding components or reducing power density, thus addressing the limitations of traditional NTC components.
Implementation Method 1
The conductive hot melt adhesive has two states: a solid state and a softened flow state. When a temperature is lower than the Vicat softening temperature of the conductive hot melt adhesive, the conductive hot melt adhesive is in the solid state; when the temperature is equal to or higher than the Vicat softening temperature, the conductive hot melt adhesive may soften and flow
Implementation Method 2
the conductive hot melt adhesive may soften and flow, thereby conducting the positive and negative electrode components of the battery
Implementation Method 3
the conductive filler is at least one of carbon, an elemental metal, an alloy, a metal oxide, or a conductive non-metal compound
Data Source
AI summary
Disclosed are a conductive hot melt adhesive, a conductive insulating tape, and a battery, where the conductive hot melt adhesive includes a matrix and a conductive filler. A Vicat softening temperature of the conductive hot melt adhesive ranges from 60° C. to 130° C., and the conductive hot melt adhesive is solid in a first state and may soften and flow in a second state. The conductive hot melt adhesive is disposed between a positive electrode component and a negative electrode component of a battery. When a temperature is lower than the Vicat softening temperature of the conductive hot melt adhesive, the positive and negative electrode components cannot be conducted via the conductive hot melt adhesive; when the temperature is higher than the Vicat softening temperature, the conductive hot melt adhesive softens and flows, thereby conducting the positive and negative electrode components.