Thermistor Heat-Conductive Layer for Hold Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Surface mountable PTC devices face challenges in increasing hold currents and sensitivity to ambient temperature due to device size limitations and poor heat transfer in high-density circuit designs.
Innovation Solution
Incorporating one or more heat-conductive layers on the surfaces of thermistors to enhance heat conductivity, with a thickness of 15-250 μm and heat conductivity of at least 30 W/m-K, and using heat-conductive connecting members to improve heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If device size is reduced for high-density circuit design, then area occupied is decreased, but heat transfer capability deteriorates
Solution Approach 1:
The patent applies composite materials by integrating a metal heat-conductive layer (high thermal conductivity) with the polymer-based PTC device structure. This composite construction enables small-sized devices to achieve superior heat transfer capability, resolving the contradiction between miniaturization and thermal management in high-density circuit designs.
2Area of stationary object
If device size is reduced, then area occupied is decreased, but hold current increases
Solution Approach 1:
The metal heat-conductive layer forms a composite structure with the PTC device that enhances heat dissipation efficiency. This allows miniaturized devices to maintain or improve hold current performance by effectively managing thermal energy, preventing premature tripping due to heat accumulation.
3Measurement precision
If heat insulation is improved, then temperature sensitivity is increased, but hold current decreases
Solution Approach 1:
The patent applies local quality by implementing heat-conductive layers specifically at critical interfaces (device-to-circuit board contact areas) rather than uniformly throughout the entire device. This localized thermal management maintains temperature sensitivity for detection while providing sufficient heat dissipation to sustain hold current.
4Temperature
If heat-conductive layers are added to increase heat conductivity, then heat transfer is improved, but device complexity increases
Solution Approach 1:
The metal heat-conductive layer serves multiple functions simultaneously: it acts as a thermal management component (heat dissipation), an electrical connection element (electrode), and a structural support layer. This multi-functionality reduces overall device complexity despite adding thermal management capabilities.
Solution Approach 2:
The patent merges the heat-conductive layer with existing device components (electrodes and circuit board interfaces), combining thermal management functionality with electrical connection structures. This integration approach minimizes additional complexity while achieving improved heat transfer.
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 significantly increases the hold current and sensitivity to ambient temperature, effectively protecting batteries and electronic products from over-current and temperature events.
Implementation Method 1
one or more heat-conductive layers are formed on surfaces of a thermistor to increase heat conductivity
Implementation Method 2
The polymeric material layer exhibits PTC or NTC behavior
Implementation Method 3
The polymeric material layer exhibits PTC or NTC behavior
Data Source
AI summary
A thermistor includes a resistive device, a first insulation layer, a first electrode, a second electrode and a first heat-conductive layer. The resistive device includes a first electrically conductive member, a second electrically conductive member and a polymeric material layer laminated therebetween. The polymeric material layer exhibits positive temperature coefficient (PTC) or negative temperature coefficient (NTC) behavior. The first insulation layer is disposed on the first electrically conductive member. The first electrode is electrically coupled to the first electrically conductive member, whereas the second electrode is electrically coupled to the second electrically conductive member and is insulated from the first electrode. The first heat-conductive layer is disposed on the first insulation layer, and has a heat conductivity of at least 30 W/m-K and a thickness of 15-250 μm.