PTC Heat Exchanger Structure for High-Voltage Shock Isolation
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Solution Overview
Problem
Motor vehicle air conditioning systems with electric or hybrid drives require high-voltage electrical heating, posing a safety risk due to the potential for electrical shock when high-voltage components are exposed.
Innovation Solution
A heat exchanger design incorporating PTC elements with printed circuit boards, insulated by a molded seal within a closed tube structure, which is easy to manufacture and ensures electrical insulation and efficient heat transfer without the need for joints, using a shrink tube and corrugated fins for enhanced thermal conductivity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage is used to operate PTC elements for heating, then the heating performance is sufficient for electric and hybrid vehicles, but the safety risk of electrical shock increases
Solution Approach 1:
The patent introduces an insulating element as an intermediary between the high-voltage PTC heating elements and the surrounding environment. This insulating element physically separates the high-voltage components from accessible areas, allowing the system to operate at high voltage (50-600V) for sufficient heating power while preventing direct contact that would cause electrical shock. The insulating element acts as a mediator that enables high-voltage operation without exposing dangerous voltage levels to users.
2Object-affected harmful factors
If traditional contact plates with insulating layers are used, then electrical insulation is provided, but the manufacturing complexity increases due to multiple components and assembly steps
Solution Approach 1:
The patent combines the insulating function with the structural support function into a single integrated insulating element. Instead of using separate contact plates and insulating layers as in traditional designs, the insulating element simultaneously provides electrical insulation and mechanical support for the PTC heating elements. This merging of functions reduces the number of components and simplifies the assembly process while maintaining adequate electrical insulation to prevent shock hazards.
3Reliability
If multiple separate components are used for insulation and support, then functional requirements are met, but the manufacturing cost and assembly time increase
Solution Approach 1:
The insulating element is designed to perform multiple functions simultaneously: it provides electrical insulation for high-voltage safety, mechanical support for the PTC heating elements, and structural integration within the heat exchanger assembly. This multi-functional design ensures functional reliability (electrical insulation and structural support) while improving manufacturing efficiency by reducing the total number of parts that need to be produced, inventoried, and assembled.
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 design allows for safe operation at high voltages by ensuring electrical insulation and effective heat transfer, reducing the risk of electrical shock and maintaining reliability and cost-effectiveness.
Implementation Method 1
PTC elements are current-conducting materials that have an electrical resistance and can conduct current better at lower temperatures than at higher temperatures. Their electrical resistance thus increases with increasing temperature.
Implementation Method 2
heat-conducting elements, in particular fins or corrugated fins, by means of which the surface area for heating the air is increased
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The heat exchanger (1) has an electrical resistance heating element (2), particularly positive temperature coefficient element. A conducting element (11) is provided for transferring heat from the electrical resistance heating element to a fluid. An electrical insulating element (22) is provided with two conductors (4). An independent claim is also included for a method for manufacturing a heat exchanger.