Electric cars: why not removable batteries?

The main problems with electric cars seem to be limited range and lengthy recharge times. Both of these would be solved if you could easily swap out the batteries at the equivalent of a gas station. This would also solve the problem for city dwellers, those for whom electric cars arguably make most sense, of plugging in when you don’t have off-street parking. I imagine a charging system where you get charged for the (electrical) charge on the batteries you take away, and credited for the charge that remains on the ones you swap out. Failing batteries can be sent for recycling by the battery company and not render an otherwise serviceable vehicle defunct. It would probably take a consortium of car manufacturers to standardize batteries and replacement method and equipment, but surely where there’s a will…

This seems such an obvious idea to me that I am surprised it isn’t at least talked about more. Is there some huge downside I am missing?

The Tesla Model S has a battery pack that weighs 1200 lbs. You need a pretty hefty piece of machinery to remove/replace/store that.

It was attempted.

Spoiler alert: it didn’t work. To the sum of $850 million.

to get any appreciable range you basically need to build the car around the battery. a vehicle designed for easy battery swap would likely be rather ungainly looking and extremely oddly proportioned.

I thought Tesla already had this, but apparently they are still working on it.

There would also need to be a way to account for (and counter) the impulse to “top-up” your car. Battery memory may be less of a concern today than it was then NiCads were first introduced, but it’s still a thing.

The Tesla Model S can swap batteries, but there doesn’t seem to be enough demand to incent the building of many swap stations.

The Model S’s battery pack is affixed to the underside of the car; as I recall, the swap involves driving the car onto a swapping machine that unbolts the battery pack, lowers it underground, and whisks it away to a charging rack, installing a fully charged battery in its place.

I think part of it is that no one wants to give up their battery pack, until it is not good anymore, in hopes of getting a better one. Much like the propane canister exchange services, If you have a new one you tend to get it refilled, till it is old then exchange it to get a better one, then repeat. It would tend to leave these exchange places with lots of bad batteries.

There’s always the Mercedes AA Class.

The Tesla battery swap process, if it is ever implemented, will account for that. If you don’t pick up your original battery from the charging station within a set period of time your account will be charged for the difference in battery life. With a replacement cost of $10,000+ that could be a hefty charge.

So that negates the whole swapping batteries so you can drive cross-country strategy? Unless you specifically stop at the same station on your way back. Seems like that kills at least 50% of the reason to swap.

Unless you are moving cross-country, your first battery swap should be within 200 miles of your home. They would charge the battery for you while you are away, so returning to pick it up shouldn’t be too much of a hassle.

The biggest users around here would be those travelling from SoCal to Las Vegas for the weekend. Drop off your battery in Baker or Barstow on your way up and pick it up on the return trip.

Packaging and industrial design. Batteries have to fit into all of the nooks and crannies (packaging) of something the the general public considers “car-looking” (industrial design). This is a tall order.

Maybe leasing is the answer, but rather than leasing the batteries, you should lease the chassis, i.e., we revert to a type of body-on-frame design whereby the drivetrain (including the batteries) is, as a whole, a separate component from the tophat. Lift the body off the chassis, and put it on a freshly-charged chassis.

Obviously, things such as custom rims and preferred tyres complicates this.

Until batteries are small enough to not require custom fitting into available space, there’s not really much that can be done. And, trust me! Your thought isn’t an original idea; it’s just that packaging and design don’t make it possible right now.

Tractors (as in tractor trailer) are a different matter, though. Industrial design is much less a consideration.

but gross vehicle weight is even more critical. every lb of battery is one less lb of cargo the truck can carry.

There may be a place for swap-able batteries but it’s a financially dangerous idea. Every battery maker is pushing hard for rapid charge batteries because the demand is already there for a variety of products. It would take billions of dollars in investments and infrastructure to make swap-able batteries work and the nano-second a fast charge battery hits the market that investment is destroyed.

I think another consideration is the sheer amperage that has to be pulled through the connector. You have to have a tight physical connection over a fair amount of surface to keep things from turning extra crispy. That’s why a lot of electrical component failures occur at the terminals.

Why not a membraneless flow battery?

Removable batteries won’t be very useful if the battery isn’t standardized. Laptops used to have removable batteries, but there weren’t any shops where you could drop off a spent battery and pick up a fully charged one.

And you can’t have standardized car batteries for the same reason we don’t have standard laptop batteries : different designs need batteries with different shapes and sizes.

do they exist outside of a laboratory?

A valid point. Commercializing flow batteries for vehicles might be obstacular, primarily with respect to profitability. But in terms of delivering gas-station plus home-charging convenience for the end user, I could see a lot of potential. It would solve some major issues with electric vehicles, if the technology were to catch on, and if they could develop an efficient reaction that does not use fucking hydrogen.