In thermal management, metals such as copper and aluminum are often used.

Metals conduct heat well.

At the same time, however, they also conduct electricity.

That is why, around electronic components and batteries,

there are many situations where you want to release heat but do not want electricity to flow.

This is where ceramic-based materials are used.

In general, materials that conduct heat well often also conduct electricity easily.

On the other hand, resin materials that hardly conduct electricity often also conduct heat poorly.

In other words, heat dissipation and electrical insulation are difficult to achieve together.

Ceramic-based materials are important for resolving this contradiction.

The roles of ceramic-based materials can be broadly divided into three.

1. Releasing Heat While Insulating

The most important role is insulated heat dissipation.

For example, in

● Power semiconductors

● EV batteries

● Power supply circuits

● Inverters

● Around power supplies in AI servers, and so on, you want to cool heat-generating components.

At the same time, however, you want to insulate them electrically.

In such situations, ceramic-based materials are used.

2. Use in High-Temperature Environments

Many ceramic-based materials are resistant to high temperatures.

That is why they are suited to use in high-temperature environments, such as

● Power electronics

● Automotive equipment

● Around batteries

● Industrial equipment

● Semiconductor manufacturing equipment

However, heat-resistant temperature and mechanical properties differ by material, so selection according to the application is necessary.

3. Enhancing Flame Retardancy and Durability

Many ceramic-based materials have the property of being hard to burn.

That is why they are important in applications where safety is emphasized, such as EVs and ESS.

Especially around batteries, not only releasing heat, but also the perspective of making it hard for heat and flames to spread in abnormal situations is necessary.

There are many types of ceramic-based materials.

Here, we organize typical examples often used in thermal management.

Alumina

Alumina is a typical insulating ceramic material.

Its characteristics are that it

● Has high electrical insulation

● Is heat resistant

● Is relatively easy to obtain

● Has a good cost balance

Its thermal conductivity is not as high as that of metals, but because it easily combines insulation and heat resistance, it is used in a wide range of applications.

Aluminum Nitride

Aluminum nitride is a material with high thermal conductivity even among ceramic-based materials.

Its characteristics are

● High thermal conductivity

● Electrical insulation

● High-temperature capability

● Advantages in power semiconductor applications

On the other hand, care is needed regarding cost and processability.

It is high-performance, but how to make it usable in volume production processes is important.

Boron Nitride

Boron nitride is sometimes used as a material with both thermal conductivity and electrical insulation.

In particular, there are applications in which it is mixed into resin as a filler to increase thermal conductivity while maintaining insulation.

Its characteristics are

● Electrical insulation

● Thermal conductivity

● Lubricity

● Ease of use in filler applications

It is important in ceramic filler-loaded heat dissipation sheets and insulating heat dissipation materials.

Silicon Nitride

Silicon nitride is a ceramic material with excellent mechanical strength and heat resistance.

Its characteristics are

● High strength

● Heat resistance

● Wear resistance

● Electrical insulation

It is considered for applications requiring high reliability.

Mica

Mica is a layered material derived from natural minerals.

In thermal management, it is sometimes used for its insulation, heat resistance, and flame retardancy.

Especially around EV batteries and high-temperature components, it is sometimes used for the purposes of

blocking heat

insulating electricity

increasing safety in abnormal situations.

It is best to understand mica not as a heat dissipation material,

but as a heat-resistant, insulating, and heat-shielding material.

Ceramic Filler-Loaded Resins

In actual thermal management materials, ceramics are not only used as plates themselves.

There are also many materials in which ceramic fillers are mixed into resin.

For example, by adding fillers such as alumina or boron nitride to

● Silicone resin

● Epoxy resin

● Acrylic materials

and so on, thermal conductivity is increased.

This creates materials that combine softness, electrical insulation, and thermal conductivity.

The main advantages of ceramic-based materials are as follows.

● High electrical insulation

● High heat resistance

● Flame retardancy

● Chemical stability

● Ease of use in high-temperature environments

● Easily contributing to safety around batteries and power supplies

They are especially important in EVs, ESS, power semiconductors, and around power supplies in AI servers.

On the other hand, ceramic-based materials also have points to note.

● Hard

● Prone to cracking

● Weak against bending

● Difficult to process

● May shed particles

● Some materials are expensive

● May lack flexibility

In other words, ceramic-based materials are high-performance, but

they are not necessarily easy-to-handle materials.

Many ceramic-based materials are hard.

Hard materials have difficulty conforming to surface irregularities.

As a result, air layers may remain between them and components.

Then contact thermal resistance increases.

In other words, with ceramic-based materials, not only high thermal conductivity,

but also the contact state must be considered.

Depending on the type, ceramics can crack easily.

Especially when processed thin or into complex shapes, chipping and cracks can become a problem.

In volume production processes, it is important that they do not break during

● Die-cutting

● Transport

● Lamination

● Winding

● Supply to automated machines

In ceramic filler-loaded resin materials, the more filler there is, the more easily thermal conductivity increases.

However, as the amount of filler increases, the material may

● Become harder

● Become more brittle

● Lose adhesiveness

● Become harder to process

● Shed particles more easily

In other words, the more you increase thermal conductivity, the worse processability can become.

This is an extremely important point on the shop floor.

In AI servers, not only GPUs but also power supply components, insulating components, and components around liquid cooling are important.

Ceramic-based materials are considered for parts requiring

● Insulated heat dissipation

● Heat resistance

● Flame retardancy

● High reliability

Especially in areas involving high voltage and high current, materials that insulate while releasing heat are important.

In EVs and ESS, safety around batteries is important.

Ceramic-based materials are important in

● Inter-cell insulation

● Thermal runaway countermeasures

● Heat shielding

● Flame retardancy

● Insulation around busbars

● Insulation from cooling components, and so on.

In EVs and ESS, both releasing heat and

not spreading heat in abnormal situations are necessary.

In this respect, ceramic-based materials are an important option.

Power semiconductors handle high voltages and high currents.

That is why heat generation is large and insulation is also necessary.

Here, ceramic substrates and insulating heat dissipation materials are important.

In other words, in power semiconductors, the three requirements of

heat dissipation

electrical insulation

reliability must be satisfied at the same time.

In research and development, the following kinds of performance are required of ceramic-based materials.

● High thermal conductivity

● Electrical insulation

● Heat resistance

● Flame retardancy

● High reliability

● Low outgassing

● Mechanical strength

● Thinness

● Compositing with resins

In other words, ceramic-based materials are materials for considering heat and electricity separately.

Let heat through.

Stop electricity.

This is where their great value lies.

On the shop floor, not only material performance but also processability is important.

For example,

● Chipping

● Cracking

● Particle shedding

● Burrs

● Interlayer delamination

● Thickness variation

● Lamination misalignment

● Breakage during transport, and so on can become challenges.

In other words, with ceramic-based materials, not only material performance,

but also processing methods

supply format

volume production stability are important.

In volume production processes, the following kinds of problems can occur.

● Chipping during die-cutting

● Particle shedding at the edges

● Cracking of thin materials

● Stress cracking during lamination

● Cracks during transport

● Breakage during supply to automated machines

● Poor compatibility with adhesive materials

● Lamination defects with insulating layers

When these occur, they affect not only thermal performance but also insulation performance and safety.

In other words, with ceramic-based materials, handling them without breaking them in volume production is extremely important.

OTIS is not a company that develops ceramic materials themselves.

However, we may be able to contribute in the area of processing ceramic-based materials into a form that can be used in volume production processes.

What matters from OTIS’s perspective is

● Processing into the intended shape

● Suppressing cracking and chipping

● Taking particle shedding into account

● Laminating with adhesive materials

● Stacking with insulating films

● Laminating with dissimilar materials

● Making them into a form that is easy to handle in automated processes

● Suppressing variation in volume production

● Managing die durability by shot count

While ceramic-based materials offer high performance, they are difficult to handle.

That is precisely why processing that makes them usable in volume production is important.

At OTIS, through

● Evaluating the processing of ceramic-based sheet materials

● Evaluating the processing of mica-based materials

● Processing of insulating heat dissipation materials

● High-precision die-cutting

● Thin-film processing

● High-precision lamination

● Lamination with adhesive materials

● Lamination of dissimilar materials

● Reel supply

● Designing supply formats for automated processes

and more, we may be able to contribute to bringing ceramic-based materials closer to a state in which they can be used in volume production.

Especially in AI servers, EVs, ESS, and power semiconductors, insulation, heat resistance, heat dissipation, and flame retardancy must be considered at the same time.

On the other hand, OTIS is not a company that specializes in

● Development of ceramic materials themselves

● Ceramic sintering

● Powder design

● Filler formulation design

● Improving material properties themselves

● Dedicated thermal simulation analysis

However, in the area of making ceramic-based materials into a form that can be used in volume production processes, we may be able to play an important role.

★★★★★ EVs and batteries

★★★★★ ESS and energy storage systems

★★★★★ Power semiconductors

★★★★★ Around power supplies in AI servers

★★★★☆ Semiconductor manufacturing equipment

★★★★☆ Industrial equipment

★★★★☆ Communication equipment

Ceramic-based materials conduct heat and stop electricity

Ceramic-based materials are extremely important materials in thermal management.

What is particularly important is that they release heat while insulating electricity.

In AI servers, EVs, ESS, and power semiconductors, heat generation and electrical insulation must be considered at the same time.

That is why the importance of ceramic-based materials will increase further in the future.

On the other hand, ceramic-based materials also have challenges, such as being

● Hard

● Prone to cracking

● Prone to particle shedding

● Difficult to process

In other words, ceramic-based materials are high-performance, but require ingenuity to handle in volume production.

And simply choosing the material is not enough.

Process it into the intended shape, maintain its insulation, avoid breaking it, and put it into a state in which it can be used stably in volume production.

Only when all of that works does it function as a thermal management material.

 

Column Supervisor: Koji Kakumoto (President, OTIS Co., Ltd.)

After studying abroad and working in planning and development at a trading company, he joined OTIS Co., Ltd. in 2011. While primarily working in the Corporate Planning Department, he has also served concurrently in manufacturing and technical divisions, and since 2018 has served as President, working to drive business growth and strengthen the organization.

 

This article is a general technical explanation intended for educational purposes and does not refer to any specific company, product, or technology.