• • • ELECTRIC VEHICLES • • • Batteries vs fuel cells for


zero emission vehicles Marcus Sampson, business line manager for transport at TÜV SÜD, says the UK Government’s 10-point plan sets out its approach to accelerate net zero goals


P


art of the UK Government’s 10-point plan will see the sale of new fossil fuel cars and vans banned after 2030. Vehicle


manufacturers are therefore investing heavily in electric vehicle (EV) R&D to radically transform the way we drive, and battery development is at the heart of this process. However, while consumers are familiar with the traditional combustion engine, and therefore accept the well-known risks associated with fossil fuel powered cars, there is still an element of distrust relating to relatively new and unfamiliar EV technologies.


Comparatively lightweight and long lasting with good performance, Lithium-ion (Li-ion) batteries have proven invaluable in EV development, and improvements in design, materials, construction, and manufacturing processes means their safety has dramatically improved. However, these batteries still present many electrical hazards, such as electric shock, arc flash burn, heatwave/fire burns and explosion, which could include shrapnel and hot molten metal. Of course, because of the energy requirements to power EVs, high voltage / high-capacity battery packs are needed, therefore presenting an electric shock and energy hazard.


It is therefore essential that people working with and using high voltage systems are aware of the potential dangers and protective measures. As the global demand for innovation in EVs increases, so the need for qualified testing of lithium-ion batteries, and education about their use and care, will also continue to grow.


Global regulation The World Forum for the Harmonisation on Vehicles is responsible for harmonizing global technical requirements and protocols for the homologation of all types of vehicles and components.


R100 is a United Nations Economic Commission for Europe (UNECE) regulation that addresses the safety requirements specific to the electric power train of road vehicles, as well as high voltage components and systems. The second revision of R100 introduced significant changes in the overall type approval process for RESS such as EV batteries.


International standards organisations set the mandatory regulations, such as the Economic Commission for Europe (ECE) in the EU, with BSI setting national standards in the UK. Three key safety standards apply to battery requirements – E/V’s: UN38.3 for the safe transport of batteries,


34 ELECTRICAL ENGINEERING • MARCH 2023


with BS EN IEC 62660 -1/2/3 and ISO 12405 -1/2/3 covering performance, abuse & safety requirements


Safety testing


Ensuring the safety and reliability of Li-ion batteries requires thorough and accurate testing. EUCAR (European Council for Automotive R & D) has developed a scale to define the level of danger associated with handling batteries for automotive applications. This methodology and risk profile can help define the test programme, which includes:


• Life cycle testing – verifies how long a battery lasts and demonstrates the quality of the battery. These tests include environmental cycle testing and calendar life testing.


• Performance testing – demonstrates the efficiency of batteries, such as performance testing under various climatic conditions.


• Environmental and durability testing – demonstrates the quality and reliability of a battery through tests including vibration, shock, EMC, thermal cycling, corrosion, dust, salt and humidity.


• Abuse testing – simulates extreme environmental conditions and scenarios to test batteries beyond limits.


• Dynamic impact tests – simulates a real vehicle accident to determine the true safety performance of the battery when the car body is deformed.


• Transportation tests – UN 38.3 is a series of tests to verify the robustness of batteries against conditions encountered in shipment.


Safety tips for battery module and pack designs include:


• Use physical partitions and fire breaks to minimise fire propagation;


• Employ good thermal management;


• Use pressure vents / relief mechanisms to safely deal with excessive pressures;


• Utilise sensors and a battery management system to identify abnormal behaviours;


• Use materials appropriate for foreseeable temperatures; and


• Use constructions with adequate mechanical strength appropriate for the real world.


There’s no doubt that EV battery technology has developed at pace but nonetheless the requirements of industry to deliver this transition effectively and on time will require significant effort from all involved. There are still major challenges faced by battery manufacturers, and by the entire EV industry, but there are countless innovation opportunities. Of course, battery safety and testing must be a key consideration, with the need for longer range, reduced charging times and minimised battery degradation driving innovative designs and developments. This will make EV battery specifications and compliance ever more critical.


Batteries and fuel cells As battery electric vehicles (BEVs) are recharged from the electricity grid, overall carbon dioxide emissions will be reduced if the method of electricity generation emits less carbon dioxide per charged vehicle than those which use hydrocarbons as a fuel. Likewise, hydrogen fuel cell electric vehicles (FCEVs) have no tailpipe emissions, so provided that either green or blue hydrogen is used, overall carbon dioxide emissions will also be reduced.


One aspect that is commonly overlooked for FCEVs is the ability to effectively trade hydrogen. To achieve net zero, a substantial portion of vehicles will need to be hydrogen powered, but consumers will not buy such vehicles until they can easily refuel them. That will require accurate measurement of the fuel delivered, so they pay for what they get, and a widely available refuelling infrastructure, so they can get to their destination reliably.


It is therefore no surprise that globally there are currently significantly more BEVs than FCEVs, as the capital costs associated with building a hydrogen refuelling station (HRS) mean that they are less common than the relatively low-cost BEV charging points. In the UK, only a handful of hydrogen refuelling stations exist, compared to nearly 100 in Germany - which has set out clear milestones to increase this significantly further. However, FCEVs do have several advantages, such as a larger range of 400 km and above, compared to a range of around 250 km for BEVs. This is because, when compared with fuel cells and petrol/diesel engines, battery packs store much less energy by weight. On range alone, hydrogen seems to have the upper hand. In addition, FCEVs can be refuelled in a few minutes, whereas BEVs can take several hours to


electricalengineeringmagazine.co.uk


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48