The emergence of alternative propulsion technology in vehicles is currently centred around the use of batteries to store electrical energy. Although the way in which batteries may receive electrical charging energy could change as technology matures, it is likely that battery systems will be the method of energy storage in a vehicle for many years to come. Commonality of charging systems and connectors is now progressing with most electric vehicles in Europe utilising the Combined Charging System (CCS) Standard1, which defines a standardised charging connection system, first defined by the International Electrotechnical Commission and now adopted in ISO standards.
It is noticeable that many charge points being provided at various retail locations in the UK are protected in a very limited way from very changeable weather conditions.
The vehicle and the charge point will undertake a series of handshaking checks before the electrical recharging supply is introduced, however whilst the physical connection of a vehicle to a charging system in this situation does not present significant risks to an individual, in most cases vehicle recharging following connection is undertaken unsupervised. Recent studies have concluded there is a risk that issues can occur with the batteries themselves whereby faults within the battery cell system can cause ignition2. This does not seem to relate to a particular configuration of battery - there are different types available but fundamentally lithium is the key item in all current battery designs.
A phenomenon known as “Thermal Runaway” continues to receive attention on social media and in technical journals3. This is where failure in one battery cell possibly caused by minute degradation of the insulating material used in the battery cell construction, can cause short circuits, overheating and ignition. Further combustion can then be fuelled by the insulating material itself which in some cases generates oxygen, thus accelerating its own destruction.
Failure of one cell then presents a localised heat build-up which transfers to other cells and causes a chain reaction which will result in a fire of a magnitude difficult to predict and prevent, spreading to the remaining parts of the battery system and then potentially onto the vehicle itself. In some cases, the outcome is the total destruction of the vehicle and potentially other items in the vicinity.
All vehicles and charging systems incorporate technology that monitors very carefully temperature changes in the battery systems, both when charging and discharging, and this temperature monitoring and control is vital.
In some cases, to ensure optimal temperatures are maintained battery pack systems incorporate cooling and temperature control, as it has been proven that monitoring effective temperature control of a battery system can prolong its lifespan.
High standards of manufacture of the cells themselves by high quality battery manufacturers further minimises the likelihood of a defect. This could become an important consideration as we begin to see the emergence of battery refurbishment enterprises.
We have seen recently an upsurge in enquires associated with insurance coverage of the batteries fitted to electric vehicles.
Electric vehicle technology is now becoming widespread for all sizes of vehicles and the technology is being used not just in the car industry but also for bus and rail applications. Currently battery systems are being trialled on small EMU (Electric Multiple Unit) trains.
Cost of the batteries per vehicle can be up to £150,000 or 50% of the cost of the vehicle
With large vehicles such as a bus the cost of the batteries is significant - on full electric bus (i.e. if propulsion relies solely on energy from batteries), the cost of the batteries per vehicle can be up to $150,000 or 50% of the cost of the vehicle4.
Many operators are finding it necessary to manage this additional cost by initially purchasing the batteries, selling them on to a maintainer and provider (normally the company providing the charging equipment) and then leasing the use of the batteries from the provider as part of the charging technology provision. This arrangement should be considered both in the insurance chain of liability and in establishing the true replacement cost of a vehicle.
In conclusion, we must continue to remain vigilant of risks associated with the storage of energy. Although electric vehicles provide the opportunity for cleaner, greener transportation, the battery pack is a storage of energy; and just like another energy source it’s use needs to be risk assessed, and have all elements in place on an ongoing basis to ensure the risk of an unexpected release of energy is controlled.
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1 http://tesla.o.auroraobjects.eu/Combined_Charging_System_1_0_Specification_V1_2_1.pdf
2 UCL Chemical Engineering Study - https://www.youtube.com/watch?v=uN8HcqAtDSY
3 https://www.sciencedirect.com/topics/chemistry/thermal-runaway
