PTC Ceramic Composition for High-Voltage EV Heating

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Solution Overview

Problem

PTC semiconductor ceramics used in electric vehicles face challenges in achieving high breakdown voltage and efficient thermal regulation at high on-board voltages, requiring thicker components and complex safety technologies to operate safely.

Innovation Solution

A semiconductor ceramic composition based on BaTiOs with specific doping and co-doping of elements like Y, La, Ce, and Nb, along with the addition of silicon dioxide, which enhances breakdown voltage and self-regulation, allowing operation at high voltages without excessive component thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PTC semiconductor ceramic is used for high-voltage operation in electric vehicles, then breakdown voltage increases, but component thickness must be significantly increased

Engineering Contradiction:
Improvebreakdown voltageVSAvoidcomponent thickness
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent changes the chemical composition parameters of the PTC semiconductor ceramic by incorporating specific dopants (lanthanum, cerium, praseodymium, neodym) and adjusting the BaTiO3-based compound formulation. This modifies the electrical properties to achieve high breakdown voltage (≥600 V) while maintaining thin component geometry, resolving the contradiction between voltage handling and thickness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ceramic material system combining BaTiO3-based compound with multiple dopant elements (rare earth elements like La, Ce, Pr, Nd and transition metals like Mn, Nb, Ta). This composite approach enables simultaneous optimization of breakdown voltage and self-regulation properties without requiring increased component thickness

Inventive Principle:
Principle #40Composite materials

2Reliability

If complex safety technologies are added for high-voltage operation, then reliability improves, but device complexity increases

Engineering Contradiction:
Improvesafety for high-voltage operationVSAvoidcomplexity of safety technologies
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The PTC semiconductor ceramic exhibits intrinsic self-regulation properties where resistance automatically increases at elevated temperatures, providing built-in thermal protection. This self-service mechanism eliminates the need for external complex safety systems, fuses, or control circuits, achieving high-voltage safety through the material's inherent physical properties

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts the safety function from separate external safety devices and integrates it directly into the PTC ceramic material itself. The material's intrinsic properties (breakdown voltage ≥600 V and self-regulation) provide the safety function that would otherwise require additional components, simplifying the overall device architecture

Inventive Principle:
Principle #2Taking out (Extraction)

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 the use of PTC heating elements in electric vehicles at high voltages up to 800 volts without the need for complex safety technologies, reducing component weight, energy requirements, and increasing battery lifespan and vehicle range.

Implementation Method 1

Semiconductor ceramics, whose electrical conductivity decreases with increasing temperature due to increasing resistance, exhibit thermal self-regulation, which can be used as heating elements. This effect is also known as the PTC effect (Positive Temperature Coefficient).

Methodology Applied
Scientific EffectPTC effect (Positive Temperature Coefficient): Thermo-resistive Effect

Implementation Method 2

PTC ceramics also have the unique feature that their resistance increases abruptly at a certain temperature. This enables self-regulation, since an increasing current also leads to a higher temperature, whereupon the resistance of the material increases and the current flow decreases.

Methodology Applied
Scientific EffectPhase transition: Phase Change

Data Source

PatentEP4491599A1PTC semiconductor ceramic composition, method for producing the semiconductor ceramic, and heating device and use thereof
Publication Date: 2025.01.15 MAHLE INT GMBH
  • EP4491599A1 patent drawingFigure 1
  • EP4491599A1 patent drawingFigure 2a~4
  • EP4491599A1 patent drawingFigure 5

AI summary

The invention relates to a semiconductor ceramic composition, wherein the semiconductor ceramic composition comprises a BaTiOs-based compound according to the following formula [BabCacSrsPbpRx][TitAaMnm]O3+z as the main component, wherein R represents at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and wherein A represents at least one element selected from the group consisting of V, Nb and Ta and wherein the variables b, c, s, p, x, t, a, m and z are defined as follows: b=1−c−s−p−x 0 <c+s+p<0,51 0,490<b<0,999 0,0<c<0,5 0,0<s<0,5 0,05<p<0,5 0,001<x<0,01 1,000,<t+a+m<1,011575 0,9889<t<1,000375 0,00010<a<0,0012 0,0001<m<0,01 0,0001<z<0,01. sowie ein Verfahren zur Herstellung der entsprechenden PTC-Halbleiterkeramik, die Verwendung der PTC- Halbleiterkeramik sowie eine Heizvorrichtung, welche die PTC-Halbleiterkeramik aufweist.