EDITOR ’ S CHOICE STAYING AHEAD IN EV DESIGN
TFC
Avoiding long lead times with careful planning
According to Next Green Car , 2021 saw the largest ever annual increase in the number of electric vehicle registrations . Over 305,000 were registered , a 74 per cent increase compared with 2020 . Here Simon Ward , technical manager at TFC , shares three ways EV manufacturers can stay ahead of the demand curve .
In 2021 , the Government brought forward its ban on new petrol and diesel vehicles from 2040 to 2030 . This target has accelerated the EV market boom , creating pressure on design teams to deliver innovation , and impetus on production teams to maximise capacity . So , what can design teams do to stay ahead of consumer demand ?
COPING WITH INCREASED ROTATIONAL REQUIREMENTS
Drive systems for EVs typically have much higher rotational capacity requirements than internal combustion engine vehicles ( ICEs ) — 15,000 revolutions per minute ( rpm ) or more . These applications where high rpm is integral to a product ’ s function can pose design challenges , because traditional retaining rings fitted on rotating shafts are limited by centrifugal forces and can yield during installation due to the component ’ s heavy cross-section . Higher rpm risks the centrifugal forces becoming great enough to expand and lift the retaining ring from the groove , causing assembly failure at high speed .
Options to reduce this risk include adding wire ties through the holes of the circlip , or using an additional component to captivate the outside diameter and thus prevent ring expansion . However , these approaches can increase assembly time , weight and add significant additional costs to the finished product .
EV manufacturers can face this challenge head on by specifying technical components designed specifically for high rpm . Smalley Revolox™ Self-Locking Retaining Rings , for example , have a ‘ dimple and slot ’ design that means that after installation , the dimple is trapped in the slot and the ring locks into place . As the ring rotates it expands , engaging the dimple and slot mechanism and preventing any further expansion . Compared with non-locking alternatives , this offers a much higher rpm capacity .
DEALING WITH ADDITIONAL CONNECTORS
Another challenge is that EVs can have around double the number of fluid connectors of a traditional vehicle . EV batteries , for example , need additional cooling systems to regulate temperature , which increases connector requirements . Design engineers require connectors that can fit in tight spaces and withstand the temperature and pressure conditions .
As well as impacting the design , the requirement for additional connectors can increase time spent during assembly , making it more difficult to keep up with demand . To combat this , design engineers can specify specialised components .
32 PECM Issue 58