Interview with Thomas Lorenz, One Mobility
“Welding aluminium requires experience and tight process controls”
Thomas Lorenz has more than 13 years of experience in advanced connection technologies, LV and HV systems, and automotive component investigation.
Thomas Lorenz
How can aluminium be used consistently in LV and HV contact systems without compromising reliability? One Mobility’s Thomas Lorenz explains where aluminium already wins – and where engineering discipline remains critical.
As vehicle electrification
accelerates at an unprecedented pace, material decisions in wiring
harnesses and contact systems are becoming increasingly strategic. Aluminium is
gaining ground in both low- and high-voltage applications, offering clear
weight and cost advantages. Yet its consistent and scalable use still raises
technical, qualification and process-related challenges.
Thomas Lorenz, Technical Specialist at One Mobility, has
more than 13 years of experience in advanced connection technologies and
automotive component investigation. Having supported OEM programmes across BMW,
Daimler, Porsche, Audi, VW and Bugatti, he brings deep practical insight into
contact systems and failure analysis.
At the Bordnetzkongress 2026 in
Ludwigsburg, he will speak on Consistent Use of Aluminium for LV and
HV Contact Systems. Ahead of the conference, we had the opportunity to
speak with him.
ADT: Looking ahead five years, what will be the single biggest
challenge for the wiring harness and EDS industry and why?
Lorenz: The biggest challenge will be keeping up in terms of speed
with some non-European OEMs. They have learned a lot from observing us but were
never slowed down by bureaucracy to the same extent, solving problems with
experience rather than paperwork.
Which material or joining decision being made today will
have the longest lasting impact on reliability and lifecycle cost?
To be honest, copper and aluminium will never fully replace
each other; it depends on the use case and often a mix is an acceptable
solution. However, the more aluminium is used for components, the higher demand
will rise. A lot of companies are working on fuses, switches and relays based
on aluminium or with a focus on connecting them to aluminium for this reason.
Aluminium is becoming far more common today than when we started using it in
2001 in the VW Phaeton as a cable, and it took until 2014 to introduce the
first aluminium terminal into series production with BMW at that time. That is
a long time and shows how difficult it can be to break established rules
regarding material selection. Even today, it is not common knowledge that these
materials can be used as reliable electrical contacts.
Where does aluminium clearly win in weight, cost or
supply chain and where does it still struggle technically?
It is a clear win in areas where cables and busbars need to
conduct high currents. Depending on the vehicle architecture, this applies to
the charging cable between the DC port and the HV battery, module connector
cables, connections inside PDUs or between inverter and e-motor. Starter generator
cables and ground cables in the LV sector are also well established. It remains
challenging in areas where different materials are mixed and where the
technologies to create reliable contacts, for example by welding, are not yet
sufficiently established. Connectors and bolted solutions are possible but
consume a significant amount of space, especially when stacked in battery or
PDU areas. Welding is therefore highly relevant, but welding aluminium and
copper requires experience and tight process controls. Staying with Cu/Cu or
Al/Al combinations makes processes much easier to control and avoids critical
intermetallic phases that can occur in Cu/Al connections when liquid state
welding is used.
What are the key joining and contact challenges such as
galvanic corrosion, fretting or contact resistance and how do you mitigate
them?
For Cu/Al, the main challenge lies in process control and
the experience required to keep it stable while ensuring it remains
cost-effective and reliable enough to sell or use. With aluminium to aluminium
connections, the primary concern is corrosion. However, inside PDUs or HV
batteries, the corrosive environment is far less relevant compared to what can
occur in certain LV scenarios. Solutions are available for these cases as well.
How do qualification and test methods need to adapt for
aluminium to be accepted broadly in HV applications?
Environmental qualification tests should remain the same. In
the best case, no one should notice that the material has changed when
comparing results. This is straightforward, with the exception of corrosion
testing.
What should engineers change in design rules if they
switch from copper to aluminium consistently?
It is less about changing design rules and more about
understanding that there are many different alloys to choose from, depending on
what you want to achieve.
Finally, what do you personally hope to take away from
the Bordnetzkongress 2026?
New contacts, inspiring conversations and the
perspectives of other companies.
