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Someone please explain to me why we have built electric cars so that the battery is fixed to the car and gets recharged rather than making the batteries swappab

• toomuchtodo 7y ago
  We own two Teslas. Charging overnight at home (daily) and within ~20 minutes at Superchargers (traveling) vs battery swaps would not make a big difference in our experience, and adds significant physical (swapping a 1200 lbs battery) and accounting (value of battery) challenges. Battery swap doesn’t exist because it’s a solution looking for a problem.
• viburnum 7y ago
  I think Renault tried in Israel it but wasn’t promising. Batteries are really heavy!
• Reason077 7y ago
  In most cases, recharging is much cheaper and more convenient than battery swapping ever could be. Batteries are big, heavy, and expensive. Significant infrastructure would be required to handle and recharge them at swapping stations. Standard sizes/formats for batteries would need to be established, restricting the design and innovation of vehicles that use them. While I'm sure someone facing a 30+ minute wait in line for a charger would be happy to pay $50 for a 10-minute battery swap instead, this situation only happens once or twice a year at times of exceptional demand (like Thanksgiving). The rest of the time, those swap stations would just sit unused, losing money.
• nickbauman 7y ago
  The batteries are huge. The Tesla Model S's 85 kWh battery pack weighs 1200 lbs.
• timwaagh 7y ago
  possible but expensive. you'd need something like robotic arms swapping the battery to do it quickly. would also require the vehicles to have their batteries at the exact same spot, in the same format and precludes using the frame of the car as a battery.
• Lendal 7y ago
  They tried that. I don't know the details, but Tesla did build a few battery swap centers. They ended up not going that route. I don't know the exact reasons why it didn't work out. My guess is the batteries are too heavy to move around with reliability, efficiency and speed.
• ajb 7y ago
  Actually for a while there vehicles were designed to swap out the entire motive unit as well as the energy supply. You could even use different motive units for different purposes, such as long distance, larger loads, small journey etc. This technology was called the 'horse and carriage'. :-) But joking aside I do wonder whether exactly this would be practical with non-living motive units. With modern tech it wouldn't be hard to control a separate traction unit, with its own wheels, at the front of your vehicle, and you could swap an electric one for a fossil fuel (or rented larger battery one) for long journeys in exactly the same way. I guess it would just be hard to design in such a way that it fulfilled all the things we expect from a modern vehicle, such as high stability, low drag, maneuverability, etc.
  • Reason077 7y ago
    > "With modern tech it wouldn't be hard to control a separate traction unit, with its own wheels, at the front of your vehicle" What you are describing is the tractor-trailer (aka semi-trailer) truck. It would indeed make practical sense to swap tractor units when moving important cargo over long distances where fast charging facilities are unavailable. It's already done today with fossil-fuelled trucks for various reasons. But for private automobiles, the advantages are very niche/narrow and wouldn't be enough to outweigh the impracticalities and disadvantages that you mention.
• tenpies 7y ago
  I think the problem is the business models. EV manufacturers rely on the gas savings to make their product financially enticing. The battery is the crappiest part of the vehicle. It will be the costliest and fastest major component to wear out. It will be the most toxic for the environment. If it can be recycled at all, it will not be economically effective to do so. If it cannot, safe disposal will be very expensive. Any "swap the batteries" model would expose that EOL cost of EVs because the battery swap company would have to deal with those dead batteries. An EV also becomes a much less appealing financial proposition when the cost is upfront vehicle cost + lifetime monthly cost for battery swap service.
  • justin66 7y ago
    > If it can be recycled at all, it will not be economically effective to do so. That's quite ridiculous.
• roland35 7y ago
  There are a few reasons I think: Battery packs are often now integrated into to structure of the car as well to save space, weight, and help with crash ratings. EV batteries also require more than just an electrical connection. Most EVs (besides the Nissan leaf) have liquid cooling/heating so you'd have to manage those connections as well. Many EVs have different size battery packs as well. It would be hard enough to manage all the inventory swapping one type of battery, let alone 50!
• justin66 7y ago
  Initially, the Tesla Model 3 was capable of swapping its battery quickly. IIRC it had the assistance of some sort of hydraulic lift (there's a Musk demo on youtube, I'm sure). The car lost this capability when they added the armored skidpad needed to protect against road debris puncturing the battery.
  • Reason077 7y ago
    It's the Model S which had/has quick-swap capabilities. Tesla even built a couple of public swap stations in California at one point to test it out. The Model 3 has a different battery design that was never designed for swapping.
    • justin66 7y ago
      You're right, my typo, too late to correct. I was not aware there were ever public swap stations, I'd be super interested in reading about that. (in particular how the economics of battery swapping were predicted to work)
    • toomuchtodo 7y ago
      The public swap stations were a requirement to max out ZEV credit values. Once that was no longer a requirement, the capability was deprecated.
      • Reason077 7y ago
        True. But while CARB rules may have provided the impetus for Tesla's battery swapping experiment, I don't think it changed the outcome of it.