~ Overcoming challenges related to EV connector compatibility ~
We don’t need to worry about compatibility when it comes to most electrical devices because we use standardised connectors and a nationwide standard mains voltage. However, things are not so simple when it comes to electrical vehicle (EV) connectors, which are regularly made to different specifications depending on the manufacturer. Here Dawn Robinson, European Product Manager Industrial at electrical connector specialist PEI-Genesis, discusses the ever-changing landscape of EV connectors.
It is generally accepted that the widespread adoption of EVs will play a key role in reaching net-zero carbon emissions. According to National Grid ESO’s Future Energy Scenarios 2021 report, there will be over 37 million EVs on Great Britain’s roads by 2050. To accommodate this, the engineering industry must continue to innovate to overcome challenges related to EV connector compatibility.
Often, problems around connector compatibility are caused by EV manufacturers prioritising different charging options in their designs: mode 1 for slow charging from typical home outlets, mode 2 for faster charging from specially designed home outlets, mode 3 for commercial street-side charging points and mode 4 for rapid, direct current charging.
Types of EV connector
Currently, EV manufacturers typically use one of four types of EV connector: type 1, type 2 including the Tesla supercharger, CHAdeMO and CCS.
Type 1 connectors were among the first to be used on EVs. These circular connectors have five separate pins for delivering single-phase AC power between 3 kW and 7 kW, as well as signalling and earthing. Type 1 connectors are typically used in Asian markets and have been replaced by type 2 connectors in most western applications.
The type 2 connector features an additional two pins and can carry either three-phase AC or high current DC depending on the configuration. These are the go-to connectors for most European manufacturers.
Tesla uses a modified version of the type 2 connector that currently only fits Tesla EVs. However, Elon Musk recently confirmed that, by the end of 2021, Tesla will open up its global network of EV superchargers to other manufacturers providing they either use Tesla’s connectors or have an adaptor to connect to its equipment.
CHAdeMO connectors, designed in 2010 by a Japanese consortium, provide purely DC power at high currents and voltages and are known for the short time it takes to charge an EV using them. Finally, a CCS, or Combined Charging System connector, is simply a type 1 or 2 connector with an additional two DC pins that facilitate rapid DC charging.
The perfect plug
EV connectors must combine several design features. They must be ergonomic and easy to use, be space efficient, include built-in safety features and be able to provide both AC and DC power. CCS connectors already combine all these design features, so the problem is solved, right? Not quite.
They fulfil the customer requirements of an EV connector, but from an electrical engineering perspective there’s more to be done. For instance, the high voltages and currents present when an EV is charging forms the perfect environment for arcing between the contacts. Only a second of high voltage arc between contacts would be enough to score and scorch them. If this damage occurs on a charging station it would mean replacing the connector, but if the damage occurs onboard the EV it could mean that people are left stranded with a dead car.
A little extra effort in the design of the contacts can pay dividends in mitigating against this. An ideal example is the RADSOK® technology from Amphenol, which use specialised hyperbolic geometry to provide robust, high-density mating between contacts in their EV connectors. Instead of passively mating, these connectors are designed to push against the respective contact to ensure a complete and reliable connection.
So, while it seems like the EV charging conundrum might have found an answer in the CCS, a little bit more effort and consideration of the subtleties means an ideal, future-proof design could be just around the corner.
To find out more about the challenges related to EV connectors, visit www.peigenesis.com or give us a call on +44 (0)2380 621260.
