Thick Film Resistors for High Performance E-mobility Applications

Innovative products are being developed for e-mobility applications to meet specific customer requirements. The main focus is on ensuring the safe operation of electric vehicles. Custom-developed thick film resistors, for example, ensure that the DC link on DC-AC inverters in the electric powertrain is discharged quickly and safely. In this post, we take a look at the following questions:

 

  • What exactly is a thick film resistor?
  • Where is it used?
  • How is it made?
  • What are the advantages?
  • How does the production process work?
  • What do you need to watch out for when buying?

 

Learn more about power electronics for e-mobility

What is a thick film resistor?

Resistors are rated with a classification according to the manufacturing process and the materials used. Thick film technology enables very low to very high ohm values.

With a thickness of 10 µm, the thick film resistor is a thousand times thicker than a thin film resistor. Its ohmic range is 0.05 Ω to 100 GΩ. This is influenced by the geometry of the resistor. The maximum operating temperature is between +150 °C and +275°C.The voltage range is up to 200 kV, although when connected in series, this can be even higher.

Development teams in the industry are working on making resistors as small and as powerful as possible.

Are you looking for a reliable manufacturer of thick film resistors?

Sabine Kamper-Rottensteiner - Solution Team Industrie

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Where are thick film resistors used?

They can be easily integrated into a limited space. Equipped with additional temperature sensors, they ensure controlled and safe dissipation of electrical energy in the DC link.

 

Thick film resistors are used in many industries. These include:

 

  • E-mobility
  • High-speed trains
  • Aerospace
  • Medical technology
  • Energy transmission and distribution (HVDC / Smart Grid)
  • Power generation / renewable energy sources
  • Energy storage (battery management systems)
  • Charging infrastructure
  • Industrial machines and controls

 

For e-mobility they are used in the following applications, among others:

 

  • Frequency convertor (power inverter)
  • Battery management system (power distribution)
  • DC/AC converter
  • Charging infrastructure equipment
  • Onboard charger

When selecting a thick film resistor, the design and the exact parameters are custom-built to the application and requirements of the customer. This means it fits perfectly into the installation space and optimized components can be used with the highest power density.

How are thick film resistors made?

Thick film resistors are made from a layer of metal oxide paste. Due to the special composition and processing of the thick film paste, it is ideal for many applications. The thick film paste is applied to a high-quality ceramic substrate using a screen printing process. This special type of ceramic substrate efficiently dissipates thermal energy and as a result ensures a high power density.

 

Production takes place in several steps:

 

1. Prepare the raw materials, such as the thick film paste and the ceramic substrate. They are checked and cleaned to make sure they are free from contamination and damage. The resistance paste is selected in accordance with the target ohmic values.

2. The resistance layer, which can feature a specific shape and dimensions, is applied using a screen printing process. The layout, print thickness and type of resistance paste have a major influence on the ohmic value. The temperature coefficient and other technical parameters are primarily influenced by the thick film paste used and the process parameters.

3. In the next step, dry and bake the resistance layer to sinter it to the ceramic substrate. A protective layer containing glass is printed over the resistance layer and is also sintered.

4. Next comes the stabilization process, which fixes the final parameters and completes the basic manufacturing process.

5. During the quality check and testing phase, it is ensured that the thick film resistors meet the required quality and technical specifications.

 

The manufacturing process requires precision and time to ensure the quality of the final product. Stable production parameters are largely responsible for our high-quality standards.

What are the features and advantages of thick film resistors?

1. Performance

Thick film resistors are high performance components, which is why they are used in many electrical and electronic systems. Due to their high performance, they are also important components in electric vehicles.

2. Fail-safe design

Thick film resistors can be designed so that they interrupt the circuit in the event of a fault. This protects the system from major damage. One example of this is the safety components in a powertrain.

3. Temperature resilience

Another advantage is their high temperature resilience. This is very important in e-mobility applications so that the resistors continue to deliver high performance even when a lot of heat is generated.

4. Extended service life

They are also very reliable and have a long service life.

5. Space saving

The latest thick film technology offers a combination of high electrical load capacity and low space requirements. In e-mobility, they efficiently conduct, distribute, and regulate electrical currents.

6. High power density

Due to their structural design, they achieve the highest power density. A large part of the heat dissipated can be transferred to a defined cooling system by a very efficient thermal connection.

7. Built to customer specifications

Thick film resistors can be customized to meet various customer requirements.

8. Wide choice of connections

Due to a wide choice of connections, such as wire, fast-on, solder-pin connections, and cable or screw contacts, there is almost no limit to the options.

What do you need to watch out for when buying thick film resistors?

The following factors should be considered:

 

  • Before you specify your thick film resistor, you should know the required ohmic value for your system.
  • Check the required tolerance range. This will avoid unnecessary costs.
  • Consider the power capacity to prevent overheating.
  • Pulsed applications often place higher demands on thick film resistors. In this case, talk to the manufacturer.
  • Include parameters such as temperature coefficient, voltage coefficient and partial discharge, among others.
  • Decide to go for thick film resistors that you are sure meet your quality requirements. They need to match the components in your system.
  • Make sure that you purchase your resistors from approved companies with IATF 16949 certification.

Would you like more information about our resistors?

Sabine Kamper-Rottensteiner - Solution Team Industrie

Contact us now!

Higher power density in e-mobility using thick-film resistors

Miba Resistors, former EBG, is part of the Miba Group. It is a leading international manufacturer of customer-specific thick film resistors for high-performance applications. With us, you benefit from a reliable partner with industry certification. We can meet your specific performance specifications thanks to our in-depth knowledge.

For more than 50 years, we have been ensuring that energy is converted and transmitted safely and efficiently. Our development teams are working with a strength in innovation on ever smaller and more powerful resistors for our customers — true to our tagline: “Technologies for a Cleaner Planet.

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