Electric vehicle charging cables

With the positive, predicted growth of electric vehicle consumption, suitable and reliable charging infrastructures go hand in hand. Safe cabling systems underpin charging networks of all shapes and sizes. Equipment manufacturers, charging station owners and governments - all play significant roles in helping to provide a sustainability future for electric vehicles becoming one of the main modes of transport.

Electric vehicles (EVs) have been recognised as a viable, clean and cost-effective solution to reducing greenhouse gas emissions. Industry standards such as IEC 62893 series and EN 50620, have been introduced to ensure that all EV cable can be assessed to a high quality and only safe product is installed in the market.

Electric vehicle charging cable challenges

1.Fast electric charging infrastructures

The rate at which an EV can be charged is becoming a key hurdle to overcome when trying to develop the market and meet government incentives to help the environment prosper. It is clear to see that charging an EV’s battery is currently, a lot slower than refilling a tank with petrol to go the same distance. This displays the fact that at present, EVs are a lot less convenient when compared to their fossil fuel, diesel and petrol counter parts.

The time it takes to charge an electric vehicle can be as little as 30 minutes or more than 12 hours. This depends on the size of the battery and the speed of the electric cable charging point. An EV is only able to charge at the maximum charging rate that the charging point can provide. For example, regardless of the kW, the rate at which an engine can turn energy into movement, the car will only charge at 7kW if it is connected to a 7kW charging cable point. The charging rate of a vehicle can also be impacted by the temperature within which it operates, meaning it could take slightly longer in colder climates.

Fast-charging EV stations are prone to high temperatures and high resistance. This results from the high level of electrical charge being transmitted down the charging cable, designed to do so in the shortest possible times allowed for that cable or charge point type. For this reason, it is crucial that the highest charging cable quality, for each charging mode, is used in all infrastructures. An efficient conductor will allow maximum current and a protective sheath will help towards temperature control.

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2. Vehicle-to-grid charging systems

Vehicle-to-grid is a technology that enables energy to be pushed back to the power grid from the battery of an electric vehicle or electric car with the intention of smart charging. Smart charging enables the balancing of electricity demand and reduces any unnecessary costs for constructing new power generation plants. Smart systems also help to overcome underlying issues and the question as to whether or not national grids, in their current setups, can meet electrical demand during peak charging times.

With the adoption of such systems, users are able track peak charging times and, in the future, will be able to benefit from selling any surplus energy supplies back to the grid. However, the EV user will need to opt for 2-way charging to allow data to be transmitted to and from the vehicle. Smart systems can communicate when the vehicle needs to be unplugged and how full the battery should be, in order for smart charging to work effectively.

These smart charging infrastructures must be equipped to transmit both power and data. Therefore, charging cables need to have efficient transmission capabilities, whilst being able to deliver fast charging current and withstand external environmental factors, such as temperature which could compromise the performance of the charge. Within both EN 50620 and the IEC 62893 series there are several tests to simulate scenarios that a charging cable will go through, during installation, use and to measure the performance of these cables. Some examples include:

  • Pressure testing at high temperatures to measure the performance of cables when they could potentially heat up in service and soften the insulation or sheath
  • Electrical testing such as insulation resistance or surface resistance is used to measure the performance from both a transmission and safety perspective, as higher resistance fits is common in faster charging modes
  • Water immersion testing to ensure the cable is water resistant, a requirement which is specified by EV cable standards. EV charging cables in outdoor environments may be expected to charge for long periods of time and likely to be exposed to rain or weathering

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3. Public vs private electric vehicle charging

Due to a lack of public charging infrastructure some EV users are forced to charge dangerously, for example, attaching multiple extension leads to one another from a private source despite knowing such systems should not be used outside. Many government incentives have been developed with a commitment to improving the infrastructure of public charging points. The UK government has introduced a grant scheme for charging point manufacturers to encourage installation of safer public charging. Similar to this, in the Middle East, Dubai previously reached their aim of 100 charging points by 2015. These initiatives all attempt to close the gap between the number of EVs in use vs the availability of charging points.

There are many factors governments needs to consider when expanding charging infrastructures, and therefore the importance of using approved charging cable. For example:

  • Charging points tend to be installed by private manufacturers with no incentive to maintain cabling systems once installed
  • Public charging points tend to be located outdoors, in carparks or docking stations, and are therefore exposed to extreme weather conditions, leading to premature aging of components including the cables
  • Fast charging points involve transmission of a higher currents, this increases operation temperatures

A sustainable infrastructure must be built to last, highlighting the importance of cable testing. For example, thermal aging and chemical testing will indicate the cables ability to stand the test of time in all weather conditions. If the charging points are not being regularly audited using approved cable gives piece of mind and performance guarantee when initially installed.

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The need for more and reliable electric vehicle charging points is globally recognised as electrification takes a stronghold, and diversification from traditional energy sources continues to change and grow. BASECs holistic approach to charging cable testing and certification ensures any approved cables holding the BASEC mark of quality, evidence the highest levels of safety and can accommodate the required charging speeds and rates. All whilst standing the test of time for continued operational reliability in remote, public or private charging locations.

Download the EV charging cable testing and certification guide or contact the team experts to discuss further.

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