INDUSTRY FOCUS AUTOMOTIVE


If electric vehicles (EVs) are to run at maximum efficiency, the components they rely on, such as power connectors, must be made using the most accurate and economical production processes. Jeff Kiernan, commercial director at Dawson Shanahan, explains


E


lectric vehicles (EVs) are the future. According to a recent report from Deloitte, electric cars


will reach a tipping point by 2022. The cost of owning an EV is likely to reach equivalence with that of a ‘conventional’ car powered by an internal combustion engine. In terms of volume, China has set a target of two million annual sales by 2020, while EVs may account for more than half of all new car sales by 2040. However, meeting the need for zero tailpipe emissions at an affordable price is not easy. Before it can happen, the cost of the underlying technologies – from motors and batteries, to bearings and connectors – has to fall. While EVs often look identical to conventional


Boosting EV efficiency with


cold-formed connectors


cars, there are many differences under the chassis. In particular, the design of the powertrain will be almost unrecognisable, with one example being the typical linkage connecting the engine and wheels. In some cases, an EV will rely on four electric motors, one for each wheel, so ‘traditional’ powertrain designs will not work. Designers of EVs are therefore having to use completely new components that have less to do with traditional car design and more to do with the electrical and electronics sectors. Even though emissions of an EV are zero, designers must still strive for maximum efficiency. In a conventional car, inefficiency raises fuel consumption, meaning higher emissions. With EVs, higher efficiency is key to enabling them to travel further on a single charge. This will require development across the board – from futuristic technologies such as ultracapacitors (which may surpass the performance of lithium ion batteries) or ‘humble’ power connectors that ensure minimal power losses within these new designs of powertrain.


COMPONENT IMPORTANCE With EVs, one area of development is to specify bearings that work at higher speeds, while withstanding electric arcing. Another area is power connector technology, which helps designers reap higher efficiency from motors and powertrains. Power connectors are widely used in the charging


units and motors of electric vehicles. The focus for manufacturers is to improve their efficiency while reducing weight and cost. One option is to engineer the connectors using precision cold forming, which enhances part quality while significantly cutting metal waste. While EVs improve environmental performance,


by slashing tailpipe emissions to zero, cold forming can generate around 80% less scrap than other machining processes. Other advantages, such as faster lead times, superior surface finish and improved mechanical characteristics, make it a technique worth considering for connector manufacture. Cold forming is performed at ambient


temperatures and offers the ability to make components to order in short lead times.


As well as delivering cost savings, cold forming produces higher quality parts because it plasticises metals along their grain boundaries rather than cutting across them, resulting in parts with low stress deformation and high mechanical integrity. Components made this way undergo work hardening, which further


improves their machinability and durability. It also reforms the structure of metal in a way that prevents further dislocations, resulting in a stronger component. The ability to make precision parts is important as it will have a


significant effect on the performance of the final component, or the system of which it is a part. There is almost no limit to the shape, size or complexity of components that can be made using cold forming, and it is capable of making everything from simple to highly complex components. If we are to meet Deloitte’s prediction of price parity by 2022, EV


designers will have to embrace every possible production technology in order to produce cars that can perform as well as existing models, at a price that the consumer can afford.


Dawson Shanahan www.dawson-shanahan.co.uk


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