If you haven’t already, the likelihood of your shop performing a repair on an Electric Vehicle (EV) has never been stronger, with approximately 115 new EV models expected to hit the road over the next 12 months. More critical for the Transmission repairers are the already existing Hybrid vehicles that are equipped with High Voltage systems and an electric Motor in the Bellhousing of the Transmission.
In fact, scores of shops are already in the throes of this “electrifying shift,” converting space and training technical staff to take advantage of this exciting era of Transmission repair.
To be fully ready for this transformative time, I cannot overemphasize the critical importance of key safety considerations that must be in place before any such repair can be performed on these high-voltage vehicles. And this begins with some safety basics, including Personal Protective Equipment (PPE).
EV Safety Tool Box
Let’s start with the best tool in your possession: Observation, Knowledge, and Assessment
EVs share many similarities and operational principles, but they are not all the same. Take time to become familiar with the overall vehicle, from understanding the location of all the HV systems and their parts to cables and how these elements are routed. Assess if any of these items are damaged.
I can’t overstate that the inspection process starts when the customer drives the vehicle in or the flatbed drops it off in the lot outside. There are aspects of BEV/HEV repairs that are different from conventional petroleum-fueled vehicles, thus, you should be aware of everything from the HV battery’s state of health to its cooling system and HV systems, in addition to all of the usual mechanical and body inspection points.
Unplug The Charging Port
While it may sound like common sense, it’s very important to understand that anytime you work on an EV to, completely unplug from the charging port. When the charger cable is connected, the high-voltage contacts will be closed, which is dangerous to anyone working on the vehicle. I appreciate the desire to have a fully charged battery, which is good for the customer. But when we’re working on an EV, we’re working on a high-voltage system. The first rule is to unplug this cable! Have that basic consideration memorized, as this is easily forgotten.
Pre-Scan Verification
Pre-scanning the EV will allow you to verify the absence of any faults in the vehicle and gain confidence in the overall electrical integrity of the high-voltage system. Scanning an EV needs to be comprehensive diagnostic with checking the State of Health of the Battery. For example, looking up Live Data and verifying Cell Balancing is extremely important to understand if the Vehicle or Battery is in danger of a thermal runaway. Proper diagnostic tools that give you access to this Data are needed to work on EVs.
Lock Away the Key
Again, this may sound like a no-brainer, but I suggest physically moving an EV vehicle’s key/key fob to an external area – even a lock box – to avoid the possibility of triggering a “live,” high-voltage system.
High Voltage Safety Gear
Look, I recognize that PPE can feel cumbersome when you’re wearing it, but it truly is your best defense. Additionally, some may outfit themselves with PPE, but not correctly wear this critical safety gear. Please wear the PPE, and wear it properly. It can save your life!
To that end, welding gloves are not appropriate PPE! Nitrile gloves, those green, black, and blue ones, are NOT high-voltage safety gloves. They’re great for working with chemicals and other things, but you do not want to trust your life to those when working on a high-voltage system.
Instead, you need “Class 0” gloves, sometimes called lineman gloves. These are the gloves you need whenever you are working with an active EV. In the event of a high voltage exposure risk, they provide an additional safety redundancy for you. In the event of some unknown fault or compromise, it’s your last line of defense.
Leather protectors are to be worn over top of lineman’s gloves and should not be used for any other type of work so they don’t end up picking up any metal splinters or anything like that. They are there to protect the lineman’s gloves from getting punctured or damaged whenever you’re doing work (Figure 1).
Keep those gloves on when you pull the battery service disconnect. This is often the time when the temptation to take the gloves off becomes real, but please fight through those thoughts and leave the gloves on.
Shop Preparation
There is absolutely zero room for error, which is why EV safety preparedness begins well before a Hybrid or EV vehicle rolls into your bay. – Specifically:
Designated Room for Repair – That EV repair section needs a clear 16 ft. radius surrounding it roped off with proper EV safety signage/no trespassing. A clean work environment is extremely important for the repair. When high-voltage connections are open during repair, please always cover them and protect them from any dirt or dust. This is important, especially when removing transmissions on hybrid vehicles. Contamination could be the root cause of battery fires, and unfortunately, there’s a reality and you want to eliminate any possible “fuel to the fire” for scenarios like this
- Tagging – Using a color-coded labeling system to tag each EV serves to alert all staff members to the status of a vehicle before the battery has been officially disengaged (Figure 2).
- Green = all clear
- Yellow = active, but current state unknown
- Red = high voltage and/or battery cell damage detected
- Lock Out – Once an EV/Hybrid rolls inside, it’s very important to commit the designated space within your shop where BEV/ HEV vehicles are being repaired and access can be limited to those authorized to work in the space. Yellow and black tape and caution/danger signage are all important elements to reinforce the importance of this dedicated environment while ensuring that each and every staff member understands the seriousness of these life and death boundaries.
- Disconnect – Once inside the shop in the designated space, it’s critical to engage the vehicle’s parking brake to prohibit any tire rotation that could create a charge. Then it can be put on the lift for further inspection and the disconnecting procedure of the High Voltage System. Especially when you work on a hybrid transmission, the battery must be disconnected from the vehicle system and verified for the absence of voltage to eliminate any risk of electrocution (Figure 3). Please follow the Vehicle specific OEM’s Disconnecting Procedure.
Another great source is looking into OEM’s Emergency Response Guides (ERG). Each BEV/HEV OEM has devised an ERG or called “rescue sheet.” These free materials are available online from every manufacturer, and there is a great app (EV Rescue app) available for free where you can look up every vehicle. This will help you to identify at a glance where the High Voltage architecture and components are located.
OEM Repair Procedures – Before Pulling Service Disconnect
Please ensure you have the OEM procedures available before you start pulling the service disconnect. Not just read them beforehand but have them with you at the vehicle. That way, if you’re having difficulty getting that disconnect out, you can look at the procedures and understand all the interlocks and disengagement steps needed before you attempt to get that disconnect out. Disconnecting the High Voltage Service disconnect and verifying the absence of Voltage is most important when you are performing work on and around Hybrid Transmission Technology (Figure 4).
No Place for Complacency
There is a tendency to view an EV repair like “any other.” There is absolutely no substitute for pulling OEM repair procedures. I would certainly encourage any shop exploring EV work to follow OEM recommendations for certifications and training around High Voltage Technology.
