What is CHAdeMO and CCS? Everything you need to know about charging EVs
Shaun · Oct 22, 2021 09:51 AM
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Electrification is coming. The debate on whether electric vehicles (EV) are actually cleaner than combustion engine vehicles or hybrids will become irrelevant when regulations around the world proceed to prohibit combustion engines.
The EU, for example, has accelerated the ban of combustion-engine cars to 2035 and China aims to make all vehicles sold after 2035 to be electrified.
Let’s start with charging. EVs can be charged via alternating current (AC) or direct current (DC). But regardless of AC or DC charging, batteries can only be charged and discharge on DC. It’s only a matter of where the conversion of AC to DC happens, either at the charging station or in the vehicle's converter.
Domestic socket such as the ones in your house is always AC, but charging stations can be either AC or DC. All EVs and even hybrids will have a converter built in, called the onboard charger. It converts AC to DC and then charges the battery.
Why can't everything just be DC?
Households use AC due to its efficiency - the ease of transforming to any desired voltage with minimal energy loss. And because it exhibits less energy loss, transmitting power across longer distances is also easier. Considering the distances between power stations and households, it’s clear why AC is used.
The main difference between AC and DC charging for EVs is the charging speed. Converters in charging stations are larger and thus able to convert AC power much quicker than via the vehicle's onboard charger. This is similar to mobile devices like smartphones whereby the charging plug does the conversion.
Charging Modes
Next thing you should know is the charging modes. According to the International Electrotechnical Commission (IEC), there are 4 charging modes specified under the IEC 61851 standard – Mode 1-4.
Mode 1 is the simplest mode that does without any safety devices in between the EV and charge point. This is highly discouraged as it risks tripping the circuit breaker if power consumption exceeds the protection limit or worse, risks fire due to non-compliance of electrical installation. Because of this, this mode is prohibited in some countries.
Mode 2 also refers to charging from household outlet like Mode 1, but there’s a control and safety device called the in-cable control and protection device. This is commonly seen bundled with plug-in hybrids. It adds a layer of protection against excessive current or temperature over Mode 1. However, charging capacity is limited to the max rating of the outlet, which is up to 3.7 KW depending on region and country.
Mode 3 uses a dedicated charger, commonly referred to as a charging station (also called EV charger or EVSE - electric vehicle supply equipment) that is permanently connected to the electrical grid, with control and protection functions. Charging power is higher than Mode 2, ranging from 3.7 kW to 43 kW.
In Mode 4, the AC to DC conversion happens at the charging station, which means it’s the only mode that refers to DC charging. As mentioned earlier, it can provide a much higher power output, exceeding 150 kW. For this mode, there are two prominent charging standards – CHAdeMO and CCS combo.
Types of charging ports
Which bring us onto the types of charging ports. Since there are AC and DC charging, the charging ports are also separated by AC and DC.
For AC charging, only two you need to take note of - Type 1 (SAE J1772) and Type 2. Type 1 is used by Japanese EVs like the Nissan Leaf, but most EVs sold here, including the Porsche Taycan (and all European plug-in hybrid models), use Type 2.
There is also GB/T but that is exclusive to China, and Tesla’s proprietary connector that supports both AC and DC charging.
PHEVs also use Type 2
As for DC charging, there is CHAdeMO and CCS (Combine Charging System). The latter basically enhanced version of the Type 1 and Type 2 ports (CCS Combo 1 and CCS Combo 2), with two additional power contacts.
CHAdeMO (abbreviation for CHArge de MOve) on the other hand, is the official standard in Japan. Unlike CCS, it does not share parts with the AC connector and requires an additional, specific inlet for CHAdeMO. However, CHAdeMO is losing the race as just about every other EV maker has agreed to the CCS standard.
But really, just like mobile devices with USB-C and Lightning ports, there’s always a fight for standardisation. There’s no need to fret over it because adapters, if they aren’t already, will be available.
Single-phase vs three-phase
You may have also heard of the terms single-phase and three-phase power supplies. Without getting into the details on the sine waves with its peaks and troughs, the simplest explanation is that three-phase power provides a more consistent, steady supply that is more accommodating to higher loads.
It increases the power density of the system, which in turn increases the charging capacity, up to 22 kW (Mode 3). However, the EV will need to be able to accept 22 kW in order to utilize the fast charging.
Conclusion
To sum up, there are two types of charging – AC and DC. The four modes (Mode 1-4) specified under the IEC 61851 standard further breaks down the AC and DC charging. For AC charging, there are only two charging ports you need to know - Type 1 and Type 2.
As for DC charging, it’s CHAdeMO and CCS (CCS 1 and CCS 2), which are essentially enhanced versions of the Type 1 and Type 2 ports.
There’s more to learn about EVs such as the battery capacities or the electrical architecture, but we’ll save it for the next article. For now, this is all you need to know about charging an EV.
The quest for automotive knowledge began as soon as the earliest memories. Various sources information, even questionable ones, have been explored including video games, television, magazines, or even internet forums. Still stuck in that rabbit hole.
