I have an EV which seems to keep the same charge for weeks at a time without topping it up but I hear that grid scale batteries have a lower storage duration than an EV battery. Why is this the case and what is the typical storage duration of a grid scale storage battery?
Edit/clarification:
I’ve read that grid scale storage only keeps charge for four hours, how and why is this the case if an EV battery can keep charge for weeks?
In: Engineering
Storage duration for grid storage is not how long time they can store the energy if nothing is used. It is for how long time they can provide the designed power output if they are full.
So a 4MWh battery storage facility that can output 1MW only have a storage capacity of 4/1= 4 hours. That is the time it take output all stored energy.
An electic car would if you look at it the same way have a short storage duration too. A Tesla Model Y long range all-wheel drive has a 81kWh battery and a peek power of 286 kW (384 HP) So at max power output it will drain the battery in 81/286 = 0.28 hours or if you like 17 minutes.
The car cant output max power all the time, the batteries, engine controller, and engine will likely overheat. The question is alos how to use max power for very long time, the car speed is electronically limited, and you likely need to pull a heavy trailer uphill at high speed.
A more practical value is the given 395 km highway range in mild weather. The number assumes a constant speed of 110km/h so it take 395/110 = 3.6 hours so empty the battery pack.
So an electric car has a few minutes to a few hours of storage capacity depending on how you look at it. The peek power compared to stored energy is likely higher than typical grid storage. It has nothing to do how longe time the energy would get drain from drainage inside the battery if it is not used.
a
Latest Answers