why the new electric Volkswagen car will be able to charge within 15 minutes but phones can still take hours to fully charge



why the new electric Volkswagen car will be able to charge within 15 minutes but phones can still take hours to fully charge

In: Technology

Not sure about actual numbers here but here’s an example

Phone cord transfers 100w per whatever time
Phone battery holds 3000w, takes a bit to charge

Car charger transfers 10000w per whatever time
Battery holds say 30000w, charges much faster.

Probably has something to do with battery materials. Car batteries can be charged much faster, as you have much more power coming from the charger and the batteries can handle more w/t than your phone can.

Your phone needs to be handheld, portable and small. Your car doesn’t. Your car can have active fans cooling, liquid coolant. Your phone can’t. Your car charger can have access to a 100kw power supply, your phone is limited to the 1500 watt circuit in your house.

Many years ago I listened to a podcast (Scientific American maybe) where they interviewed an MIT scientist who worked on battery research. He claimed there is something about the molecular structure of a normal lithium ion battery that limits how fast a battery can be charged. In his research he had found a way to change the battery’s molecular structure. He claimed to have produced a phone battery that could fully charge in 10 seconds. According to his estimates, with a powerful enough electric source (higher voltage than household current) you could fully charge a car battery made this way in about the same time it takes to fill a gas tank. Supposedly the technology was patented and the only thing left was to work out the technical issues with mass production. After listening to that podcast I thought that fast charging batteries would have been the norm long ago.

They are probably using different battery chemistries, not all li-ion batteries are the same.

Phones don’t draw much power, which allows a battery chemistry to be chosen for maximum capacity. Typically these high capacity batteries have higher internal resistance and get hot when charged quickly.

A car battery needs to be able to deliver a significant amount of power, so a different chemistry will be chosen with a lower capacity per cell but a lower internal resistance for high power delivery. Generally chemistries designed for high drain can be charged faster too. In addition as someone else mentioned the car can have a cooling system to keep the battery cool while charging.

Finally if you look carefully at the wording it doesn’t say “15 minutes to fully charge”, it says 15 minutes to 300 mile range. These are very different statements, the last 10-20% of battery capacity takes much longer to charge (can often be significantly longer than the charge from 0-80%). With plenty of phones they say things like “a days use from a 15 minute charge” – again this isn’t charging the battery fully.

* Excessive heat destroys batteries.
* Electricity moving through wires produces heat (when the electrons smash into other things inside the wire.)
* Car batteries can be hooked up to thick cables that
* Heat is an unavoidable part of using electricity for anything (charger batteries included).
* Have a very low resistance
* Can handle larger amounts of heat than the tiny wires used for phone charging.
* Also Car sized battery chargers can be hooked up to special high power connections in your house that phone chargers cannot. (Same as electric stove/oven and electric clothes dryers).

I haven’t seen this mentioned yet: your phone uses one or just a few cells, and you can only charge a cell at a limited speed. A car uses hundreds of cells and even tough they are grouped, those groups (called ‘modules’) can be charged in parallel, thereby bringing down the required time tremendously.

But btw even the new ID.3 (if that’s what you mean) can’t charge *fully* in 15 minutes, it still needs an hour or more for that. As mentioned in [this article](https://www.motor1.com/news/369662/vw-id-3-unveiled-frankfurt/)

> A 100-kW quick charger should provide juice for about 180 miles (290 km) in 30 minutes.

So that’s 30 minutes for the fastest segment (the common 20-80% part), so with 290 km is not even the full range, so how you came to the conclusion that it charges in 15 is not clear to me.

A lot of electric cars can be hooked directly to the power grid at charging stations which provides a lot more juice. Combine this with an air conditioning unit that cools the battery to keep it from being damaged as you heat it from charging so fast and you can get pretty fast charging. (You are still damaging your battery by charging it this fast)

It’s also important to note that you are only getting 80% charge in 15 minutes. Charging the last 20% of a battery takes longer than the first 80%.

Charging an electric car with a smallish battery looks something like this:

Normal wall outlet (phase 1): 20 hours

Dryer outlet (phase 2): 7 hours

Quickcharge outlet that houses don’t have access to in the US (phase 3): 45 minutes