Lead-Free Ceramic PTC Heating Element for Vehicle Interiors

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Solution Overview

Problem

Existing heating elements, particularly those with ceramic PTC resistors, contribute to environmental pollution due to the disposal of heavy metals, necessitating a lead-free and environmentally friendly alternative.

Innovation Solution

A lead-free ceramic heating element with PTC properties is developed, featuring a sintered ceramic body made from lead-free raw materials like BaTiO3 and optionally SrTiO3, and electrodes produced through metal deposition processes or metal pastes without glass additives, ensuring effective environmental sustainability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If lead-free ceramic raw materials are used, then environmental pollution is avoided, but the ceramic composition and manufacturing process become more complex

Engineering Contradiction:
Improveenvironmental pollutionVSAvoidceramic composition
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the chemical composition parameters of the ceramic body by using lead-free raw materials (BaTiO3, SrTiO3, CaTiO3, SiO2) with specific percentage ranges instead of traditional lead-containing materials. This parameter change eliminates environmental pollution while maintaining the required PTC properties and functional performance through optimized compositional ratios.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite ceramic material system consisting of multiple lead-free oxides (barium titanate, strontium titanate, calcium titanate, and silica) combined in specific proportions. This composite approach allows the material to achieve the desired electrical and thermal properties without relying on lead, thus resolving the contradiction between environmental friendliness and material functionality.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If electrodes are produced without glass additives, then environmental sustainability is improved, but electrode production complexity increases

Engineering Contradiction:
Improveenvironmental sustainabilityVSAvoidelectrode production process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts and removes glass additives from the electrode composition and production process. By eliminating this potentially harmful component, the electrode production becomes more environmentally sustainable. The process complexity increases but is managed through alternative deposition methods such as sputtering, vapor deposition, or galvanic deposition that do not require glass-containing pastes.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If multiple identical heating elements are arranged on a common carrier, then heating efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveheating efficiencyVSAvoidheating arrangement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple identical heating elements onto a single common carrier structure, merging their functions into one integrated assembly. This arrangement improves heating efficiency by enabling simultaneous or coordinated operation of multiple elements, while the common carrier simplifies installation and electrical connections, partially offsetting the increased structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively avoids environmental pollution from heavy metal disposal and is suitable for motor vehicle applications, providing a reliable and sustainable heating solution for vehicle interiors across various voltage operations.

Implementation Method 1

Heating elements with ceramic PTC resistors are known... The ceramic body has PTC properties. PTC stands for Positive Temperature Coefficient.

Methodology Applied
Scientific EffectPositive Temperature Coefficient (PTC): Electrical Resistance

Implementation Method 2

The ceramic body has PTC properties... Both the ceramic body and the electrodes are lead-free... The specific resistance of the heating element can be set, for example, between 10 and 500 ohm cm.

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

The ceramic body is sintered. Ceramic raw materials without lead additives are used to manufacture the ceramic body.

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 4

The electrodes or their partial layers are preferably produced in a metal deposition process. Examples of this are sputtering, vapor deposition, galvanic deposition, chemical deposition.

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 5

The electrodes or their partial layers are preferably produced in a metal deposition process. Examples of this are sputtering, vapor deposition, galvanic deposition, chemical deposition.

Methodology Applied
Scientific EffectVapor deposition: Physical Vapour Deposition

Implementation Method 6

The base material of the electrodes can be enriched with glass flux. The proportion of glass flux is preferably about 5%. The thickness of an electrode comprising Al as a base material and a glass flux as an additive is preferably 20 μm.

Methodology Applied
Scientific EffectGlass flux:

Data Source

PatentEP2057864B9Heating element
Publication Date: 2018.02.21 TDK ELECTRONICS AG
  • EP2057864B9 patent drawingFigure 1~2

AI summary

A heating element is disclosed, comprising a ceramic body (1) which has PTC properties. The heating element comprises electrodes (2, 3), arranged on the ceramic body (1). The ceramic body and the electrodes are lead-free.