Truck & Off-Highway Engineering - December 2020 - 8

TECHNICAL INNOVATIONS

currently available to us, " he said. " At the moment, the
change in powertrain technologies is driven primarily by political objectives. The current one-dimensional debate focused
on a single drive is not productive. We want a dialog that has
a basis in technology. "

'Intelligently electrified'

New hydrogen storage

A key aspect of hydrogen adoption will be on-vehicle storage
of the fuel, and during the presentation, Mahle revealed a project involving a new hydrogen fuel tank. The type-IV design
consists of a liner made of plastic and an outer casing made of
carbon fiber. Mahle is creating a new production process for
this tank that will increase its hydrogen storage density and

A new Mahle condenser helps ensure EV batteries are optimally cooled
during fast charging, while providing the necessary power for cabin
temperature control.
8 December 2020

Electric drives tested under real conditions on the electric motor test
bench in Fellbach, Germany.
make it less expensive to produce at the same time.
" This construction gives the pressure vessel a weight advantage over other designs, " explained Martin Berger, Mahle's head
of corporate research and advanced engineering. " We want to
optimize and speed up the carbon fiber winding process. This
is where we can apply our expertise in the field of plastics and
our broad experience with complex production technologies.
We are aiming for a 10-15% increase in storage density, [and]
we want to reduce costs by 10% [as] we need fewer materials
and can thus reduce machining expenses. "

Battery immersion cooling

" Fuel " storage is also an issue for EVs, particularly when it
comes to fast charging, which the Mahle execs pointed to as a
key roadblock to swifter adoption. " Instead of relying on ever
larger batteries, we need to improve the fast-charging capability, " Berger said. " This is the only way we can offer vehicles that
meet market requirements. A smaller, fast-charging battery
makes the vehicle cheaper and lighter, reduces its carbon footprint and conserves finite resources. "
To accelerate fast charging capabilities, Mahle announced
that it is working on immersive battery cooling. The setup
permits a dielectric coolant to flow directly around the cells.
Since the fluid is not electrically conductive but is thermally,
maximum battery temperatures are decreased and the fluid
improves battery pack temperature homogeneity. According
to Berger, immersion cooling will pave the way for a whole
new generation of battery systems.
" The key challenge when it comes to fast charging is thermal
management, because the charging power is limited by the
maximum temperature of the battery and by the temperature
differences in and between the cells, " Berger said. With immersion cooling, he noted: " Charging can take place in just a few
minutes - and thus makes batteries cheaper, lighter and much
more durable. This is because of the lower maximum temperature at high battery loads, and the higher temperature homogeneity significantly improves the durability of the cells. "
Paul Seredynski

TRUCK & OFF-HIGHWAY ENGINEERING

BOTH IMAGES: MAHLE

Based on Mahle's projections, full electric vehicles (EVs) will gain
their largest market-share footholds in personal transportation.
Larger commercial applications will feature longer adoption timelines requiring bridge technologies, including hydrogen as a lowemission combustion fuel and infrastructure primer before fuel
cells see wider adoption. According to its projections, full electrification is not viable in the near term for larger vehicles, with total
global adoption rates by 2030 for hybrid/EVs for personal and
commercial vehicles projected at 36% and 18% respectively.
According to Stratmann, the debate on future propulsion
technologies currently is skewed toward electric vehicles (EVs).
" There will not - and cannot - be one single powertrain of the
future, " he stressed. " Market conditions, vehicle classes and driving profiles are too diverse for this to be the outcome. "
" Road traffic accounts for a considerable share of greenhouse-gas emissions due to the use of fossil fuels. But that
doesn't mean we should restrict ourselves to battery-electric
mobility, " he added. " That's why Mahle is continuing to follow
its dual strategy: electrification, development of the fuel cell;
and the use of hydrogen and alternative fuels in an intelligently electrified combustion engine. "

Truck & Off-Highway Engineering - December 2020

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - December 2020