By Yvonne Paige-Stimson, Hexagon Design & Engineering Applied
Solutions
[email protected]
While most vehicle manufacturers know they need to transform their
business with electric vehicle product lines to remain competitive,
the
reality is that most organisations are cautious by nature and are
not racing to adopt new and emerging technologies that can deliver
a competitive
advantage. Instead, they are looking for ways to tweak their
business models with minimal risk. This is exactly why Hexagon is
committed
to accelerating electrification and the pursuit of 100% EV.
Volume XII - Winter 2020 | mscsoftware.com | 53
2020 is a landmark year for the Automotive industry – not just
because of COVID-19, but rather for an altogether more important
sustainability milestone. As a global industry, we now have only 30
years left until the Paris climate “net zero carbon emissions” by
2050 deadline arrives. Policy adoption by, at latest count, 126
countries around the world shows international alignment on a
common objective to implement policies, pledges and pursue
individual country goals for decarbonization. The scale of change
needed transcends transportation, production of goods, buildings
and infrastructure, requiring all engineers and businesses
everywhere to support the common purpose.
Globally, the big 3 (Europe, China and USA) together account for
51% of the World’s CO2 emissions from all sources, while the
transport sector globally accounts for 14% of all Green House Gas
(GHG) emissions. Emissions from the transport sector are determined
in three ways:
• Activity levels (how many people and how much cargo gets
transported how far)
• Modal share (how many private vehicles versus shared or public
transport)
• Emission intensity levels of the fuel used (how much carbon
dioxide and other pollutants are emitted per kilometer
driven).
While a number of major countries have set ambitious fuel economy
and emission standards that can substantially reduce emissions, the
science shows the needed trajectories in support of the Paris
Climate Agreement can only be reached by a massive global scale-up
of pure EVs to around 80% by 2050.
Hexagon’s focus on eMobility therefore means supporting our
customers to achieve a market proliferated with electric vehicles
offerings. By developing the product development and manufacturing
ecosystem for co-simulation tools we are putting the tools and the
know-how into the hands of people who need them to achieve the
mission for safe, performance-optimized and cost-equivalent BEVs
and CAVs. Together we will drive a faster, more integrated,
sustainable approach to the design, development and production of
electric vehicles.
There are a number of key challenges to be overcome and this is
where we focus our efforts to ensure we are enabling transformative
solutions in these areas.
54 | Engineering Reality Magazine
more integrated, sustainable approach to the design,
development and production of
Batteries
A big topic at the heart of every EV development is the battery, so
where to start? Implementation of the battery, the one vehicle
system which new energy car buyers are the most aware about, is
pivotal to success. Apart from feeling and fearing range anxiety,
the electrical energy system represents the highest contributing
cost of ownership over the electric vehicle lifetime total cost.
The challenge of integrating the battery into the platform
architecture is forever changing the previous styling conventions
and occupant packaging options of the vehicle body design studio.
An immediate impression forms when faced with one’s first EV based
on the changes around the physical structure of the vehicle with
the disappearance of the engine bay, creation of more roomy
interiors and changes in ingress and egress height, often at the
luggage compartment.
Battery safety and the risk of thermal runaway is the number one
critical engineering risk, with some recent high profile recalls
globally attributed to manufacturing defects. Mobile phone and
micro-electronics industries have had significantly more time over
a number of years to evolve quality assurance strategies to control
cleanliness, humidity and avoidance of contamination in Li-ion
battery cells. This know-how is rapidly being assimilated in car
battery plants to see off critical-to-quality battery defects
arising from raw materials, human factors, processing or the
production environment. Phone batteries have an advantage of being
significantly smaller, so can readily adopt 100% end of line
inspection methods such as CT scanning non-destructively within the
factory QC process.
China is dominating the world in deployment of electric vehicles
but domestically has suffered an outcry of consumer opinion over
much publicised thermal runaway battery fires claiming lives. In
China it will be mandatory from January 2021 that all EVs can
demonstrate compliance to a new battery safety performance standard
with defined requirements for thermal diffusion, external fire,
mechanical shock, simulated collision, thermal, ingress protection
and humidity cycling, external short circuit, overcharge and
over-temperature. Another important consideration is ensuring the
vehicle notifies both driver and passengers of an incident (that’s
one flashing hazard light you would ignore at your peril!) and the
need to incorporate an active safety method of extinguishing a
battery pack fire into the design. China is the first to define
such a performance standard and the requirements will likely funnel
concept selection decisions for the thermal management system
earlier in the design process. It remains to be seen if other
countries will also follow
Standards for the performance and durability assessment of electric
vehicle batteries JRC Technical Report published April 2019
Volume XII - Winter 2020 | mscsoftware.com | 55
with legislation as currently battery design architecture and
safety performance requirements rely on a vehicle manufacturer to
voluntarily define their own standard and deploy through APQP and
Functional Safety. Until there is a world- wide harmonised set of
EV regulations consumers will be putting their faith almost
entirely in the brand.
Battery initial performance deteriorates over its lifetime due to
usage effects of electrochemical ageing and time–calendar ageing.
This process is influenced by multiple simultaneous factors in the
chemistry, material properties, thermal and electro-mechanical
interactions. To develop a full understanding of battery ageing and
cell degradation processes is challenging. Ageing phenomena are
extremely complicated to characterise and ageing tests during the
development process to validate model predictions are both time
consuming and costly. Extension of the battery life is often
achieved by over-sizing the battery ensuring a reserved capacity in
hand. A growing technology area is to use Machine Learning and AI
algorithms to apply monitoring, diagnostics and prognostics to
optimise the state of battery charge via the Battery Management
System, overseeing the cell and battery health, all to facilitate
the prediction and optimisation of remaining useful life.
The high cost of Li-ion batteries is due to the high-cost material
contents in the cell chemistry being nickel, cobalt, aluminium,
lithium, copper, insulation and thermal interface materials and
subject to global geo-politics. Battery chemistry is evolving
rapidly due to intense research activities accompanied by huge
industrial efforts to improve performance and reduce their cost.
Vehicle companies are increasingly developing specific strategies
to maximise the first life of the electric vehicle with some having
the ability to carry out replacement of degraded battery cells,
incorporated in their overall warranty and service cost of
ownership. Meanwhile retired EV battery cells can be repurposed and
an increasing number of schemes are emerging with second use
applications such as standby power in the energy storage market.
Safe dismantling, handling and storage of after-market battery
cells remain a valid concern which shall challenge the recycling
market to ensure consistent safe-practice everywhere.
Lightweighting
Since electric vehicles have traded a 50L fuel tank for a 300kg
battery pack and added miles of copper wiring and controls
hardware, the need for the complete vehicle to overcome a
significant weight gain is a real issue. While lightweighting has
been a topic for a great many years, EV adoption requires more
substantial solutions than just saving a few kilograms here and
there to achieve the next emission band. The discerning BEV
customer will see the total range and efficiency of the vehicle as
the omni- present issue that dominates the entire buying
decision.
Engineers therefore have a real need for solutions that provide the
same functional capacity, performance and perceived quality within
the vehicle but at a much reduced and lighter weight. A 10% weight
reduction can equate to a 5-6% efficiency improvement. The
conventional principle of lightweight design is to use either less
material or materials with lower density whilst ensuring the same
or enhanced technical performance.
56 | Engineering Reality Magazine
Structural optimization is another effective way to achieve
lightweighting, by distributing material to reduce material
consumption, enhanced structural performance such as higher
strength and stiffness, and better vibration performance. Selection
of premium materials, especially aluminium alloys, metal matrix
composites (MMC) and metal foams, previously commonplace in
Aerospace, are becoming increasingly popular in BEV applications.
Aluminium with alloying agents such as lithium targets improvement
of fatigue crack and corrosion resistance, as well as enhanced
specific strength and stiffness. Scandium alloy use is being
explored for improved tensile strength and improved strength of
welds.
Traditionally the domain of motorbikes and super-cars, carbon fibre
usage is quickly gaining in popularity around the vehicle as
manufacturing methods find high volume solutions to these erstwhile
low-volume processing methods. Some of the most exciting advances
consider door frames and closure systems and even the hood
(bonnet), typically seeing 40% weight reduction compared with
aluminium equivalents while still achieving leading performance in
crash safety, durability, strength, fit, finish, NVH and weather
sealing.
An entire branch of sustainable materials development is gaining
pace to explore Automotive uses for naturally occurring plant
fibres and bio-polymers. This is targeted to avoid the
contradiction that arises if we decarbonise the fuel source of the
vehicle only to proliferate lightweight plastics, derived from
petrochemicals. The challenge is to achieve flame retardant,
durable, scratch resistant, easily formed parts that are
lightweight, sustainable, inexpensive and most importantly promote
the A-surface styled appearance. Bio- polymers and bio composites
are already gaining in favour and are certainly growing in
applications especially for cockpit interiors, bumpers and external
trims.
Powertrain
After the battery, the next highest cost items in the BEV are the
electric propulsion units, which are wide-ranging in solutions to
answer the specific needs of a given platform. Much depends on
whether the designers have had design freedom to architect the
platform and battery for the underbody before the top hat is
conceived or whether a package envelope is already quite
constrained. The energy efficiency of the powertrain and cost to
the consumer of the end vehicle still varies greatly at the point
of use.
Some electric drivetrain configurations favour the multi-electrical
motor FWD/ RWD/ AWD approach. However more motors also mean more
rare earth magnet content e.g. neodymium and being subject to
market pricing volatility as recently seen during the disruption of
China supply chains due to COVID-19. Such vehicles are typically
calling the higher price point in the vehicle showroom offerings.
If the strategy is to avoid a gearbox development being perceived
as difficult and motor- only solutions being easier, then it is the
end consumer who pays.
Where the drive units are packaged is critical for vehicle driving
dynamic and performance feel, as BEV customers will still want
great vehicles that handle well. If we follow Automotive design
conventions, we perhaps avoid powertrains on the un-sprung mass
where it can be harder to mitigate noise, harshness, and vibration
(NVH) issues. However, saving on other drivetrain hardware and
freeing space between the wheels for more battery will mean this
concept architecture will still be explored and certainly find
favour in commercial vehicles and other applications where driver
refinement is less of a critical issue.
Mainstream electric drivetrains from the larger OEMs are evolving,
making use of motors coupled to a gearbox, and enjoy the most
efficient and power-dense applications with down-sized motors and
compact eDrive packaging with integrated power electronics and
cooling circuits. Such applications benefit typically by an over
10% increase in battery range as the motor and power electronics
can be optimised to the most efficient region of the efficiency
map. Overall, they can be approximately 30% lighter, cheaper and
smaller to package than an equivalent direct drive or eAxle unit so
offer much to alleviate the overall vehicle weight target.
Volume XII - Winter 2020 | mscsoftware.com | 57
Autonomous driving
Cities of the future will need to have a market mix of electrified
mass transit and CAVs to support the net zero carbon targets. If
the vehicle can complete more journeys instead of doing ‘carpark
durability’ with standing time while the owner is in the office or
at home, then we can significantly reduce numbers of vehicles on
the roads.
The greatest challenge to autonomy is that we have not yet achieved
basic road safety to consistent high standards across the globe. A
number of countries have seen success in reducing road traffic
deaths over the last few years, but progress varies significantly
between the different regions and countries. There continues to be
a strong association between the risk of a road traffic death and
the income level of countries. Before Covid-19, road traffic
accidents represented the eighth highest global cause of deaths
with human error accounting for over 85% of all incidents. Managing
road infrastructure, vehicle roadworthiness, driver speed,
eliminating drunk driving, mandating use of helmets, airbags, seat
belts and child restraints, all remain the basic principles of
vehicle road safety to be incorporated consistently everywhere to
ensure accidents are avoided and the outcomes are not
life-changing.
Into this context we have car companies deploying AI and Machine
Learning technology with the ambition to eliminate the driver
completely so the higher decision making of the vehicle can be made
autonomously. We can see immediately how an AI can be programmed
for a given country’s infrastructure and mitigate for driver human
factors. Assuming all cars are connected and sharing decision
making to each other then we can develop solutions for all
motorised vehicle incidents. The greatest challenge to autonomous
solutions are other road users, especially cyclists and
pedestrians, and preventing their unexpected actions having a
negative consequence.
There is a consumer expectation that the vehicle should through the
vision systems be able to ‘see’ all and not to suffer human issues
of tiredness, visual distraction, colour contrast, depth of field
or reflex response delay. Equipping the vehicle with LIDAR
geospatial sensors surpasses the optical capability of a mere
driver. As the driving task becomes more automated, the role of the
driver is being changed, and one wonders what the driving test of
the future shall consist of? Investigations and analyses of crashes
involving automated features or autonomous vehicles will require a
human factors analysis and investigation to determine whether the
driver’s actions (or inactions) were a factor in the collision and
whether the system was designed in a manner that is consistent with
the known capabilities and limitations of drivers operating these
systems.
Distribution of deaths by road user type- WHO 2018
