■ EVs Run Carrying Huge Batteries
The biggest difference between gasoline cars and EVs is that EVs carry a huge battery.
Moreover, EVs are required to deliver
● High output
● Long range
● Fast charging
In other words, they are evolving toward packing a large amount of energy into a small space.
This is thermally very demanding.
■ Battery Performance Changes with Heat
Battery performance changes greatly with temperature.
For example,
● Low temperature → reduced output
● High temperature → accelerated degradation
● Extremely high temperature → thermal runaway
In other words, a battery is not just a device that stores electricity;
it is also a device that keeps fighting heat.
■ Fast Charging Is a Battle Against Heat
What is important in EVs today is fast charging.
However, passing a large amount of electricity in a short time generates a large amount of heat.
In other words, problems arise such as:
● Wanting to charge quickly
↓
● Passing a large current
↓
● Increased heat generation
↓
● Degradation and reduced safety
In other words, the fast-charging race is also a thermal control race.
■ The Greatest Fear for EVs Is Thermal Runaway
The most dangerous thing in batteries is thermal runaway.
Thermal runaway is a phenomenon in which some cells generate abnormal heat, that heat spreads to the surroundings, and temperatures rise in a chain reaction.
In other words, it becomes a state in which heat begets heat.
This can lead to
● Smoke
● Fire
● Explosion
That is why, in EVs, what is extremely important is not only how high-performance they are,
but how safely heat can be controlled.
■ Heat Problems Do Not Disappear Even with All-Solid-State Batteries
What is currently expected as the next-generation battery is
the all-solid-state battery.
It is expected to offer
● High safety
● High capacity
● High output
In reality, however, the heat problem does not disappear.
Rather, due to
● Higher density
● Higher output
● Faster charging
the difficulty of thermal management may increase even further.
■ The EV Era Fights the Contradiction Between Heat and Weight Reduction
EVs require, at the same time,
● Being lighter
● Longer range
● Being safer
● Being cooler
However, adding more cooling mechanisms means
● More weight
● Larger size
● Higher cost
● Higher power consumption
In other words, an EV is a huge complex problem of
heat × light weight × safety × cost.
■ Onboard AI Increases Heat Even Further
In addition, future EVs will advance in
● Autonomous driving
● AI control
● More sensors
● High-speed communication
In other words, future EVs will become closer to computers on wheels.
Then
● Battery heat
● Motor heat
● AI computation heat
will all exist at the same time.
In other words, future EVs may become a moving space of heat density.
■ The Researcher's Perspective
Toward technology that safely contains heat
Current research includes
● Next-generation cooling
● High thermal conductivity materials
● Inter-cell thermal insulation
● Heat dissipation structures
● Phase change materials
● Thermal simulation
● Battery control AI
From now on, not only high-performance batteries
but batteries that can safely control heat will become important.
■ The Shop-Floor Perspective
Things do not cool as theory predicts
On the shop floor, however, many problems occur, such as
● Cell-to-cell variation
● Poor contact
● Uneven heat dissipation
● Assembly errors
● Thermal expansion
● Vibration
● Long-term degradation
In other words, “safe in theory” and
“safe in volume production” are completely different.
■ In EVs, Contact Is Extremely Important
In EVs, various functional components are used, such as
● Heat dissipation materials
● Insulating materials
● Cushioning materials
● Adhesive materials
However, thermal performance changes greatly depending on how closely they adhere.
In other words, in future EVs, the final contact conditions for heat will be extremely important.
■ A Slightly Frightening Future: In the AI Era, Even the Way Things Break Will Become Visible
Furthermore, large amounts of AI and sensors will be built into EVs and robots from now on.
As a result, in the future, it is highly likely that enormous amounts of data, such as
● Temperature history
● Charge/discharge history
● Vibration
● Degradation
● Current changes
● Pressure changes
● Failure timing
will be able to be analyzed.
In other words, the future will be an era in which why it broke is visualized with extremely high precision.
This is a very big change.
Until now, problems that remained vague, attributed to
● Usage environment
● Individual differences
● Lack of reproducibility
● Unknown causes
may, through AI analysis, be identified quite clearly as
● Insufficient heat dissipation design
● Poor contact
● Heat concentration
● Material degradation
● Assembly misalignment
● Structural problems
To put it in extreme terms, in the future, it may become possible to visualize not broken products
but the design that will break itself.
In other words, in the future, just doing thermal management will not be enough.
It will be an era in which you are asked whether things truly work, including
● Long-term durability
● Temperature distribution
● Contact stability
● Volume production variation
● Performance after degradation
As a result, in some cases, it is even possible that structural design problems are discovered in large numbers, and recalls increase.
That is precisely why, from now on,
making heat work in volume production may become increasingly important.
(If a global failure-cause investigation service company emerges separately from manufacturers, the scope of manufacturing warranties and the insurance industry will likely change significantly as well.)
■ What Matters from OTIS's Perspective
From OTIS’s perspective, what matters for EV heat problems includes
● Microfabrication
● High-precision die-cutting
● Thin-film processing
● High-precision lamination
● Processing of insulating materials
● Processing of heat dissipation materials
● Contact between dissimilar materials
● Automated supply
● Volume production stability
In particular, making heat work safely in volume production is important.
■ What OTIS Can Do
At OTIS, through
● Processing of thermal management materials (heat dissipation, thermal conduction, thermal insulation)
● Processing of insulating materials
● High-precision die-cutting
● Microfabrication
● High-precision lamination
● Stacking of irregular shapes
● Support for reel supply
we may be able to contribute to making functional components for EVs and batteries work in volume production.
■ Outside OTIS's Expertise
On the other hand, OTIS is not a company that specializes in
● Battery cell development
● EV design
● BMS development
● Motor development
● Vehicle control development
However, in the area of making heat solutions work in volume production processes, we may be able to play an important role.
■ Summary
The future of EVs will be decided by thermal management
Future EVs will become
● Higher-performance
● Higher-output
● Longer-range
● More AI-driven
Behind the scenes, however, heat will become a major constraint.
In other words, future mobility competition may be decided not only by how high-performance they are,
but by how safely heat can be made to work.
And behind the scenes, technologies that support the final 1mm of heat will become increasingly important.
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.
