Date of post: 22nd July 2025
Introduction
The evolution of electric vehicles has arguably become the single most important mile stone development in motor vehicle design and function for the last hundred years, and certainly since the beginning of the 21st century.
At the heart of these developments has been electric vehicle battery technology. This has been so constant and rapidly advancing as to have seen electric vehicle driving ranges and battery cycle life increase dramatically in the last ten to fifteen years.
The most significant engineering challenges for electric vehicles remain focused upon increasing the vehicle’s driving range per full battery charge, reducing the time it takes to charge the vehicle’s battery and improving battery longevity with regards to minimising degradation and increasing the battery’s cycle life.
Advances in materials composition technology for battery cell electrodes is one of the key factors in addressing these engineering challenges. Such technologies are enabling higher battery energy densities and improved thermal and structural stability of battery cell components to be achieved.
Battery chemistry
Electric vehicle battery chemistry is at the forefront of these developments. At the time of writing, the two most dominant battery chemistries are lithium-ion, abbreviated Li-ion and lithium iron, abbreviated LiFePO4 or more simply LFP.
Other battery chemistries exist or are under development but Li-ion and LFP remain the two dominant technologies at this time.
Battery energy density is a particularly important factor when it comes to improving battery performance characteristics. The higher the energy density, the more energy can be stored and released by the battery for a given weight.
For comparison, in 2015 the average electric vehicle battery energy density was around 140 Wh / kg. Ten years on in 2025, this is now an average of around 300 Wh / kg or more in some batteries.
Battery chemistry is defined by the combination and percentage ratios of the raw materials used in constructing the battery cell components, specifically the cell’s positive electrode (cathode) but also its negative electrode (anode).
In a lithium-ion battery, the active materials used to make the cathode and anode electrodes are chosen for their ability to easily absorb lithium ions – a process referred to as intercalation.
A fully charged lithium-ion cell has a high concentration of intercalated lithium atoms at its anode.
Many automotive lithium-ion batteries are of so-called ternary type. This is where the cell cathode is made from a combination of three different metal materials.
The most common combination is Nickel, Manganese and Cobalt, abbreviated NMC. Alternatively, nickel cobalt aluminium oxide is used, abbreviated NCA.
Different ratios of these materials give different operating characteristics and energy densities. From around year 2020, a common ratio for NMC batteries has been NMC811. Broken down, this figure represents a combination of around 80% nickel, with 10% each of manganese and cobalt.
Nickel has a high electrical conductivity. When refined and alloyed with other materials, nickel increases the cathode’s energy density and capacity to give a longer driving range. It is less sensitive to low temperature so the battery can accept a charge more quickly in colder environments.
Manganese acts as a stabiliser to improve the structural and thermal stability of the cathode materials. It reduces the combustibility of cell components which enhances the safety of the battery. Manganese also contributes to increasing the cathode’s energy density to improve the vehicle’s driving range.
Cobalt has the following attributes when used in the construction of the cathode:
i) Enhances the battery’s energy density, particularly when combined with nickel.
ii) Has a high stability and long cycle life which increases the number of charge and
discharge cycles possible throughout the battery’s life span.
iii) Enables the battery to maintain a stable voltage output throughout its life span.
iv) Has a high thermal stability and heat capacity with a melting point of 1495 degrees
celsius. This makes the cathode less susceptible to overheating and catching fire.
v) Enables the battery to handle higher charging rates and accept a charge more quickly.
Another chemistry technology being used in new vehicle batteries in 2025 to enhance battery energy density are silicon-carbon composite anodes.
This composition of materials enables storage of more lithium ions at the anode which increases energy density but without increasing battery weight – the weight being a major factor in electric vehicle batteries.
Electric vehicle driving ranges
In 2025, the average latest model electric vehicles are capable of achieving between 250 and 375 miles depending upon the size of the vehicle’s battery. Some high end vehicles are able to achieve over 400 miles driving range.
Whilst these driving ranges are still lower than can be obtained from a full tank of fuel for the average internal combustion engine vehicle, the constant advancements being made in battery technologies mean that achievable driving ranges continue to rise. It will likely very soon be possible to achieve average driving ranges in excess of 500 and then 600 miles.
These mileages will bring electric vehicle driving ranges more into line with what is achievable from a petrol or diesel powered vehicle, making electric vehicle ownership more attractive.
Battery charging & charging infrastructure
There have been massive advances in electric vehicle charging infrastructure throughout the UK, particularly from around 2022 / 2023. Many motorway and main A road service areas now have rows of charging stations set aside as dedicated charging ranks in service parking areas.
With all the travelling that I do around the country, I have seen for myself how charging infrastructure has evolved in the last two to three years, and not just at motorway service areas either.
Ranks of electric vehicle charging stations have also appeared around towns, in retail park car parks, at hotels and restaurant car parks, fuel filling stations and many other public areas.
There are a wide range of phone APPs now available for motorists to download that show the nearest available charging station at any one time and also whether the charger is in use or available. Range anxiety is slowly becoming less of a problem for motorists.
Of course, there are still challenges to be addressed in terms of charging infrastructure availability in many inner city areas and some more remote rural areas.
Many modern electric vehicles now accept an Ultra-Rapid DC charge to recharge their high voltage battery from 20% up to 80% state of charge in as little as between 10 – 30 minutes.
These charging speeds enable motorists to do a short charge at service areas to top up their vehicle batteries and then move on, charging the vehicle when they arrive home or at their destination.
The way we refuel an electric vehicle mainly requires a change in habit compared to our expectations when it comes to refilling a petrol or diesel fuel tank.
Another benefit of advancements in battery materials technology has been reduced levels of natural degradation occurring in batteries over time. Electric vehicle high voltage batteries are now showing much lower levels of percentage reduction in capacity over time resulting from degradation.
Modern high voltage batteries are now capable of lasting from 20 – 25 years or more. It is very likely now the case that the average electric vehicle’s high voltage battery will outlast the life of the vehicle.
Battery voltage architecture
The importance of battery chemistry cannot be under stated as it determines the battery’s operating and performance characteristics. However, chemistry is not the only area of technical development. Other key areas are the battery’s rated voltage and its thermal management system.
The average high voltage battery is rated at around 400 volts, but some vehicle manufacturers are now using a battery rated at 800 volts in some of their vehicles. High voltage system operating voltages are defined using the term ‘voltage architecture’.
800 volt architecture in electric vehicles has several benefits. From the motorist’s point of view, the immediately noticeable benefits are reduced charging times and increased driving range.
From a technical stand point, using 800 volt architecture means that less current is consumed by the vehicle’s high energy systems for a given Wattage power output.
Using a higher voltage increases the efficiency with which the power can be transported to the vehicle’s high energy drivetrain components, i.e. the motor / generator. For a given power output, less current is consumed.
Less current allows use of thinner and lighter high voltage cables. This reduces manufacturing costs and vehicle weight which contributes towards increasing the vehicle’s driving range.
Also, less current means less excess heat is produced particularly during charging. This enables the battery to be charged more quickly and at a higher charge rate. Less heat reduces battery degradation and improves the battery’s durability and cycle life.
The components of an 800 volt architecture system need to be matched to the higher voltage in terms of their internal resistance and current carrying capabilities. It would not be possible for example to just hook up a 2012 model year Nissan Leaf to an 800 volt battery.
To summarise, 800 volt architecture has the following main advantages:
i) Less current flow and reduced current consumption of high voltage components
ii) Less residual heat generated as a result of reduced current flow
iii) Lower energy losses in conductors due to less heat and less build-up of resistance
iv) Less battery degradation
v) Thinner and lighter wiring and conductors can be used
vi) Reduced manufacturing costs due to less raw materials used
vii) Lower rates of degradation and longer service life
viii) Faster battery charging times
ix) Lighter vehicle weight contributes to longer driving range
Battery thermal management
It is well known that lithium-ion high voltage batteries are sensitive to extremes of hot and cold temperature. Over-charging and excessive discharging cause permanent damage and degradation to the battery.
Sophisticated on-board-vehicle battery thermal management systems have resolved many of the temperature related issues surrounding electric vehicle high voltage lithium-ion batteries.
This has been achieved using pre-heating and cooling systems that interact with the vehicle’s air conditioning and refrigeration system which in turn has been adapted for electric vehicles.
Most full electric vehicle high voltage batteries are now liquid cooled. Heat pump technology is a standard feature of most electric vehicle air conditioning heating and ventilation systems.
Battery management systems in electric vehicles maintain the high voltage battery’s cell voltages and temperature within safe working limits. An inbuilt battery buffer safeguards the battery against it being over charged and also becoming excessively discharged.
Battery pre-conditioning is a function of the battery’s thermal management system that allows the battery temperature to be brought within a pre-determined temperature, for example prior to driving or charging the vehicle battery depending upon the circumstances.
Some of the thermal management system pre conditioning functionality can be controlled via a phone APP. This allows the motorist for example to programme the thermal management system to pre-warm the battery prior to starting a journey on a frosty morning.
Electric vehicles – here, now and the future
I have often been asked whether I think electric vehicles are the future. My answer to that question is no, I don’t. And the reason why is because electric vehicles are the here and now and have been for the best part of almost the last two decades.
There are many positives of owning and driving an electric vehicle. Equally, there are still many detractors and those who are wary of electric vehicle technology, or just plainly don’t like them.
With respect to the question of whether or not electric vehicles are ‘the way forward’, one point to consider is this: at this time, there are now quite a lot of electric vehicles in existence that are known to have accumulated significantly high mileages – in one or two cases in excess of 400,000 mainly trouble-free miles.
Time is a proving factor. As we start to see electric vehicle technologies standing up to the test of time, this will be a major deciding factor in establishing the credibility of electric vehicles as a true replacement for the internal combustion engine.
Want to know more?
AK Automotive offer a two day on-site Electric & Hybrid Electric Vehicle Systems course for motor industry customers.
We also offer the IMI Level 2.2 and Level 3 electric and hybrid vehicle award qualifications.
Contact AK Automotive
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Alternatively, for further information, to discuss your training requirements and enquire about an on-site vehicle electrics training course, please contact Tony Kitchen at AK Automotive directly.
Contact: Tony Kitchen (AK Automotive)
Telephone: 07484 831 015
E-mail: tony@akautomotiveservices.co.uk
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Page last updated: Tuesday 22nd July 2025