Why don’t Electric Cars need oil?


I understand they use different drive trains and that the entire system is built differently, but aren’t there still moving parts that should be lubricated and maintained?

Thanks in advance.

In: 6

No. Oil is used to lubricate the moving engine parts in an ICE. None of those parts exist in an electric vehicle and thus oil isn’t needed. There is cooling fluid around the battery pack to help cool it down but it’s not oil.

Those moving parts do still need lubrication.

But with an EV you can completely cover the moving bits and then that area wont get contaminated for a long time and therefore doesn’t need maintenance as much. That maintenance cycle can be decades long, to the point that something else goes wrong long because those do.

ICE cars need their oil changes pretty frequently because the very fact of using them means they get filthy with all the soot and stuff. Which ends up getting in the oil (I don’t know enough about cars to know if that’s on purpose and the oil is specifically *supposed* to soak that stuff up or if it’s just inevitable).

The parts *do* still need lubrication, but since they are exposed to the high temperatures and frequent temperature fluctuations of combustion the lubricants don’t break down like ICE oil does. To put it in perspective, an EV motor can get up to around 140 C with normal operations, while the temperatures in the combustion chamber of an ICE can reach around 2,500 C. Granted, the ICE as a whole doesn’t get anywhere near that high (and the chamber doesn’t maintain that temperature), but exposure to those temperatures whenever a cylinder fires is what causes engine oil to breakdown over time. Well, that and the resultant residue from the engine operation and internal combustion, itself.

Yes, over time the lubrication of EV moving parts *is* going to break down, but the vehicle itself will reach an end-of-life cycle long before that.

Engine oil in a normal car is pumped around the engine to lube all the moving parts.
Electric cars don’t have an engine so they don’t need engine oil.

Transmission fluid in a normal car is used to lubricate the gears and to act as hydraulic fluid to actuate the moving parts in the transmission.
Electric cars are usually a single fixed gear ratio so they don’t have a transmission.

The one oil that electric cars DO have is usually gear oil in the drive unit. The fixed gears still need lubrication and for single-motor axles the differential needs lubrication too. Typically this oil will last the life of the vehicle because it’s not exposed to extreme heat, combustion products or friction material from a transmission, but you could technically change it if you wanted to.