The complex challenge of keeping EV charging infrastructure safe
Various trends are converging to stimulate the rapid growth of electric vehicles (EVs). But as range and charging times continue to be an influencing factor in consumer adoption, the pressure is on to put the necessary charging infrastructure in place. Public charging stations are popping up everywhere, albeit faster in some countries than others, and the market is complex and fragmented. Moreover, the charging station itself is just the user interface for an intricate web of components and connectivity – both with the vehicle to be charged and the ‘back end’ or grid. So what is the current situation regarding the testing and certification of EV charging infrastructure, and do the existing standards go far enough? André Bergervoet is Global Technical Leader (GTL) in DEKRA’s Product Testing service division which covers, amongst other things, the company’s international certification services for EV charging infrastructure. He shares his insights here.
Particularly in such a fragmented market as charging stations for electric vehicles, it is important that standardization forms a firm foundation for ensuring that all aspects of the infrastructure are both interoperable and safe. But the huge number of different components makes the infrastructure itself very complex. As a result, the testing and certification landscape can be equally confusing.
Complexity of EV charging equipment
“To examine the various standards that apply to electric vehicle supply equipment (EVSE), it’s easiest to break the infrastructure down into its individual parts – which can mainly be summarized as the vehicle itself, the charging station and the back end, which includes the grid,” says André. “Each of these elements of the charging equipment require several kinds of testing based on different standards. The types of testing can include development, wireless, safety, functionality, interoperability, performance, validation, protocol and EMC testing, for example.”
Interoperability
First and foremost, interoperability is a key issue to ensure the continued adoption of EVs; it is very important that drivers of any makes and models of vehicles can use generic charging stations, without any problems in the field. “The CharIN initiative, for example, is aimed at establishing the Combined Charging System (CCS) as the global standard to enable interoperable charging as an important component in the ecosystem. This is supported by many European, North American and Asian car makers, and DEKRA is one of the core members. There are also other protocols and standards, such as the EV-ready initiative which is backed by the French car makers, Chademo (Japan) and GB/T (China), so there are still some challenges in terms of interoperability. As long as there is no global consensus, DEKRA will remain a testing/certification partner for all of these separate initiatives.”
When it comes to the electrical safety of EVs and charging equipment, the main standard in the EU is the IEC/EN 61851 series of standards. Its general requirements apply to all EV charging stations. However, different parts of the standard apply depending on whether it is an AC or a DC charging station. “AC is currently the most widely available type of charging,” explains André. “It can deliver less power to the EV so it takes longer – often up to several hours – but it is ideal for charging at home overnight or at work during the day. DC is used for fast charging stations and the emerging trend of high-power charging (HPC), which can provide up to 350 kW of power to EVs in a short space of time. These chargers are more suitable when people are on the road, and they’re increasingly being installed alongside major motorway networks. But the availability of high-power charging poses even higher risks to safety, so it is increasingly important that the standards adequately address these risks.”
Gap analysis
The IEC/EN 61851 standard is already on its third edition and is changing all the time to keep up with the latest technical advancements. “It includes various safety features to avoid dangerous situations, such as a control pilot signal. Amongst other things, this controls the energization and de-energization and will initiate a safe shutdown of the charging station when the signal is lost, such as in the case of a damaged cable, for example,” he adds. “There are still some gaps, such as with respect to fire safety, the requirements for components acting as a safeguard, and insulation coordination. So when manufacturers come to us for certification, we first conduct gap analysis to identify issues such as these. Until they are finally closed in the IEC/EN 61851, we test against additional standards such as the IEC 61439, which covers low-voltage switchgear and controlgear assemblies. Another example is the IEC/EN 62368-1, which is applicable to the safety of communication technology equipment and goes further than IEC/EN 61851. In terms of basic safety requirements, based on the principles of hazard-based safety engineering, this standard supports state-of-the-art technology and points towards applicable standards where functional safety comes in.”
DEKRA also applies additional environmental protection standards to make sure that the high-voltage electronic equipment inside the charging station is protected from the elements such as rain, ice, dust and sand – none of these should result in any kind of hazards, according to André. “When we provide our DEKRA or KEMA-KEUR mark to a charging station, we want to be sure it’s truly safe. We never have any problems when explaining this to our customers because they agree with us on the importance of safety. To help close the current gaps, we’re active as a participating member in various technical committees and compliance working groups to support standardization relating to charging stations.”
Connectivity
Cables – the connectivity lifeline for EVs – must comply with IEC 62893, apart from so-called ‘mode 2’ charging cables. These portable in-cable control and protection devices (IC-CPDs) that ensure safe and reliable charging of EVs directly from a household electricity outlet are covered by IEC/EN 62752. Meanwhile, plugs, socket inlets and connectors that connect an EV with a charging station are covered by IEC/EN 62196 for the conductive charging of electric vehicles. “This standard currently includes AC and DC connectors, but it will be extended to include the emerging technology of HPC connectors – which are actively cooled with cooling liquid – in the new version,” explains André. “These innovative HPC connectors with their cables are opening up opportunities for more power and faster charging, without the need for larger conductors and hence heavier cable assemblies that are difficult to handle for the general public.”
Besides connecting with the EV, a charging station also has to connect with a whole range of back-end systems to provide the right amount of electricity to the right vehicle and bill the user at the right price. “The IEC/EN 60364-722 is related to the safety requirements for the electrical installation,” states André. “In terms of electronic communications, the ISO/IEC 15118 is the ‘magic word’ for the communication between vehicle, charging station and the grid (V2G), so between charging stations and EVs and between charging stations and the grid.”
Smart charging
“Another relevant test in this area is Open Charge Point Protocol (OCPP) testing. Developed by the Open Charge Alliance, the OCPP protocol is now used worldwide to correctly exchange information between the charging station and the charging station management system operated by the charge point operators (CPOs). This is important not only for billing purposes, but also to ensure the network runs smoothly by controlling energy distribution,” he adds. “So OCPP compliance testing will become increasingly important with respect to the smart grid and smart charging.” In the context of sustainability, smart homes and renewable energy systems such as solar panels or wind stations, the smart grid is an efficient way of handling energy. The vehicle or charging station can act as a kind of buffer and help to keep the grid more stable during peaks and troughs in energy demand. “DEKRA is part of the OCPP Working Group on Compliance and, in fact, our labs in Arnhem (in the Netherlands) and Sterling (in the US) have been announced as two of just five appointed labs for OCPP certification,” says André.
Still on the topic of ‘smart’ and the Internet of Things, he explains that in the near future we can expect to see a shift to a system in which the EV will automatically identify itself to the charging station, with automatic checks of whether all the outstanding invoices and fees have been paid, and so on. “This will make the system not only easier to use but also safer with respect to data security and hacking – which is currently a concern, especially as the EV is becoming part of the smart grid. Cybersecurity is increasingly included in the ISO/IEC 15118 in terms of interconnections to other systems. We actually have significant experience in this area within DEKRA thanks to our testing activities for smart home devices, for instance.”
This is just one example of how DEKRA’s wide-ranging expertise comes in useful in the very diverse area of EV charging equipment. “Besides that, of course, our testing and certification heritage in both the automotive sector (mainly based on ISO standards) and electrical industry (mainly based on IEC standards) puts us in a unique position to be involved in the discussions to ensure optimum safety as the EV industry continues to evolve,” concludes André.