The Assessor Winter 2026 PDF - Flipbook - Page 29
CELLS BURIED DEEP INSIDE THE
BATTERY
Here’s a tale from Geely to illustrate
the above problem does not only exist
for collision.
Porsche Cayenne BEV for 2026 uses the Volkswagen Group
PPE platform. The 800V architecture features a 113 kWh
lithium-ion battery with 96 cell pouches 昀椀tted inside six
modules. The anode is made from graphite-silicon and the
cathode is made from nickel-manganese-cobalt-aluminium;
there is 86% nickel.
Porsche Cayenne BEV for 2026 battery cooling system
has manifolds running the length of pack. There are
heat transfer plates above and below the cells – usually
they are only on the lower face. This is done to 昀氀atter
the recharge rate and to help manage optimal battery
cell temperature during operation.
Add into the mix the growing pains of
bringing a brand-new industrial process
to commercial scale, and we get the
‘solid state’ battery. Although there is
a race between Sony (with Honda) and
at least two China manufacturers to be
昀椀rst to market, the appearance is often
announced and rarely delivered. Work
in progress.
So, one way or another, batteries
will be with us for some time. The
prevailing ‘fashion’ (pouches to cells,
modules to direct integration) / cost
pressures / latest developments will
happen year by year….
THE VEHICLE IN USE
For the largest traction batteries found
on BEVs, the underside of the pack is
frequently on the ground clearance
line. Even if the battery is protected
by the body from impact damage,
secondary damage can occur as the
vehicle with the driver as a passenger,
skids to a rest.
Geely has a traction battery assembly
subsidiary Viridi E-Mobility Technology
(‘Vremt’), who allege cells supplied
by Sunwoda EVB between June 2021
and December 2023 were defective.
These were built into various vehicles
for the Zeekr brand and sold in China.
Geely Group are suing for around $323
million as of December 2025. In this
case Sunwoda EVB owned 30% of the
Vremt joint venture with Geely.
Geely claims that the affected battery
cells supplied by Sunwoda had
“serious quality defects” including
allegedly led to slower charging
speeds, inaccurate range displays, and
abnormal battery capacity degradation
in several Geely-af昀椀liated brands. The
claim amount nearly equals Sunwoda’s
total net pro昀椀t for the previous two
years (2023–2024).
At this very time Volvo Car (a Geely
owned company) announced the
EX60 reveal, which is one of their most
important new cars ever.
As this was happening, in December
2025, Volvo Car initiated a series of
actions leading to a notice for the
33,777 EX30 vehicles worldwide,
including 10,440 in the UK. The EX30
is built in China on the Geely SEA2
platform. The alleged defective cells
can build up lithium deposits inside
the cells which in 0.02% of all units,
which eventually shorts and can induce
thermal runaway.
The suspect cells were made between
6 September and 25 October 2025,
and were involved in an incident in
Brazil which severely damaged a
dealership. Remember, just 0.02 of
cells were suspect out of 33,777 cars.
Right now, there is no standardised or
easy way to quickly establish:
1. Is the traction battery cooling
system intact, including the heat
transfer plates inside the pack?
2. Is the battery control module,
which takes at least one internal
thermocouple input along with
monitoring energy 昀氀ow across
clusters of cells / pouches (so, not
cell level monitoring) controlling the
cooling system?
3. What is the scale of the damage to
the case, and what is the allowable
deformation before internal damage
becomes catastrophic?
www.iaea-online.org/news/the-assessor | WINTER 2026 | THE ASSESSORS JOURNAL
This time the Geely traction battery
assembly subsidiary Vremt was
supplied with cells from several
companies including….. Sunwoda EVB.
The supplier counter-claimed stating
the pack construction, cooling strategy
and BMS were all the property of
Vremt, so the fault was not theirs.
The advice was:
• Do not park in closed spaces or
under cover.
• Do not charge more than 70% of
maximum.
Not all of the cells made during this
period are defective, but a few are not
in balance with the rest inside a given
pack. As each of the imbalanced cells
is exposed to in effect over charging,
the problem can occur. The defective
cells were also used to build battery
packs for Zeekr 001, Zeekr X and smart
#3, although these affected vehicles
seem to have been only sold in China.
THE BIG QUESTIONS
The story above shows the practical
limits to triage of a BEV with suspected
battery damage. We can see the
battery cell supplier (seventh largest in
China) made a critical part which relied
on quality assembly and well-designed
thermal management systems to work.
Due to the ‘averaged’ cell performance
monitoring, it is essential to have all
cells performing in the same way.
When a problem is raised, the ‘old’
route of simply replacing the entire
pack raises issues around handling
damaged battery packs (special
packaging requirements and of昀椀cially
hazardous waste) as well as the logistics
of shipping assemblies weighing
anywhere from 200 to 700 kg.
ln turn, using the full retail price of
the battery knowing a BEV without a
battery is in effect scrap, is likely to end
up as salvage. A more interesting route
is to repair the battery, which of course
requires removal, opening it up and
investigating the internals.
A point long discussed here is the very
valuation and write-off thresholds used
by motor insurance companies. Given
this is a hugely valuable business,
change may only be possible with the
in昀氀uence of policy, to ensure more
vehicles remain on the road for longer.
Perhaps damage assessment of BEV
batteries and routing them through
specialists for refurbishment is the start
of that process.
JOURNAL
Andrew Marsh (Hon Fellow of IAEA,
FIMI) is Technical Director of AutoBody
Bible: https://autobodybible.com.
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