Why are we not already able to “instant-charge” EVs, smartphones or other batteries?
In: Physics
The only things that release lots off energy really quickly are usually explosions, flames, and sparks/arcs.
we already can. It’s called capacitor. Can instantly charge and discharge.
Among other problems, main one is that it’s too low density, so it wouldn’t drive too far.
Hi. I work at a thin film battery start up that’s an off shoot of energizer battery company.
Science is working on all of this in essence but the issues that allow a battery to “store “ a charge if you try to apply too much energy can damage the materials inside.
Its complex to execute
In China there is a brand of car that offers battery swapping stations. This an obvious solution to the charge time problem but requires a huge infrastructure investment and ideally, standard commodity batteries.
Well imagine two plastic bottles taped to each other with its necks.
Water is in one bottle at the bottom and top bottle is full of air. If you turn them around water starts flowing to the bottom bottle (imagine this as charging battery from your adapter). If you watch closely there would be exchange in air and water which means some pressure and resistance. The whole point is to do it as fast as possible so in this scenario you can spin them to help create whirlpool so water can travel on the sides and air in the middle. Simple as that.
Batteries are much complex in chemical structure but basically doing the same you need to push electrons one direction when charging and push it other direction when discharging. If you force this PHYSICAL process you create heat so you can either charge them fast with active cooling or if you overdo it and it does boom same like two bottles but one would be squeezed with hands the pressure would destroy both bottles.
So it’s physics who dosent allow us charge instantly simply because our batteries are not advanced enough yet to be charged so fast.
The battery capacity is like the weight held by a rope and a pulley.
You charge it by pulling the rope from the pulley, the higher the weight is the higher the battery capacity is.
You can pull the rope really fast and the weight on the other end of the pulley will go up pretty fast, but you may get hurt and damage the pulley and the rope and maybe your own hands, and still you will possibly never get the weight up there “instantly”, you can use technology to do it faster but not instantly
Well, if you can swap batteries, that’s an “instant charge”. For instance, if you are using a cordless drill and it’s battery has drained, you pop the dead battery out, put it on a charger and pop a fresh one in.
And this may be a surprised to you, but before “smart phones” (ie; the Apple iPhone), this is exactly what people did. If you had a cell phone, it’s likely you had more than one battery. I had a Motorola StarTac Elite and three batteries, though admittedly the batteries only lasted 8 hours. But I always had to charged batteries on the charging stand. I’d get home and swap to fresh batteries, and I carried one to work in my briefcase. When high capacity batteries capable of 12+ hours came out, it was cheaper to make non-removable batteries with the expectation that people would charge their phones over night and have enough battery power for the next day.
For EV batteries, the batteries are HUGE, heavy and dangerous, but I would love to pull up to a service station, park in some battery swap spot and have a robot swap out an auxilliary battery pack that had like 100 miles of charge on it that would take less than 5 minutes or something… similar to filling a tank with gas.
But as to why you can’t instant charge a battery, it’s because we use chemical batteries and when we charge them, we are actually forcing chemical reactions to bring the chemicals back to a state of higher potential where they can again begin to release electricity. It’s like bringing water back up a hill so you can run a watermill with the running water. You can charge up a large capacitor with power, but caps release all their energy at once.
Maybe in the future, we’ll have a different technology to instantly charge batteries, but having different batteries.
For now the best you can do is swap batteries.
As compared to other posts that already explain all of the relevant factors: it is possible to have electric vehicles that can “instantly” recharge, but not with existing systems, both in the vehicle, and the charging infrastructure. We would need even more powerful “instant discharge” charging stations that wouldn’t catch on fire, and capacitors rather than batteries.
We could, in theory, use capacitors rather than batteries to charge vehicles. Capacitors can charge up to full capacity almost instantly, but they do not have the same energy density as a battery and are meant to only hold a charge for a very small amount of time.
In a nutshell, a capacitor collects voltage, and amperage of varying charges, stores it up in a battery like device, and then outputs a known value of V and A consistently and reliably. This is generally used for electronics like computers that require relatively precise and accurate values to operate. Your wall socket in your house may output as low as 100V up to 135V at any given time. A capacitor constantly receives the incomming and variable voltage at a speed greater than it depletes, and sends out a perfect and constant 120v to the power circuit of the device it’s plugged into.
So, in theory, we could make a car that uses a capacitor as a battery, that has a very high and fast energy input, with an energy output limiter to slow and regulate the release of energy to power a car.
But, due to a very low energy density, you wouldn’t be able to fit as much energy into the physical size of the “capacitor” battery. Capacitors are also not great at storing energy, only temporarily holding it. They discharge quickly, so you would lose nearly all of your charge immediately after charging, like 25% per 10 minutes, unlike a battery that can store energy at a 5% loss per month.
This could result in being able to fully charge your vehicle’s capacitor in 5 seconds??? and could enable a driving range of 20km??? This is speculation/theory.. not real or known numbers, just pulled them out of my ass.
So, you could spend 5 seconds charging for 20km of range, or the equivalent of 25 seconds per 100km of vehicle range.
So, you would need to charge your car before leaving, and immediately drive it 20km to repeat the process. If you got out of it to go shopping and there wasn’t a charger, whatever charge you had left in it wouldxbe gone by the time you got back to the car, and you would be stranded.
The current system of charging speed vs travel distance is in place to be a reasonable balance. 20 minutes on a super charger can get someone a few hundred kilometers, and gives you a normal battery that doesn’t naturally dissipate its charge within minutes or hours.
Ideally, having a battery that can charge 80% in 3-5 minutes would be the ultimate goal of the tech, as this is how long it takes to put gas in most vehicles. It may just result in less distance than a gas vehicle can drive on a tank, and you may need to fill up 2/3x more frequently. We are already accustomed to the inconvenience and time to put gas in a car. If we can match that time to a reasonable driving distance, most people wouldn’t ever notice the difference between gas/electric.
We used to be able to carry spare batteries for our phones…
But they made them fixed for… Reasons.
Imagine you had a HUGE pile of bricks in your driveway that you wanted to move into your living room. Moving one at a time would require a little work over a long period of time – generating a little bit of heat (I.e. sweat) over a long period of time. You also probably wouldn’t scratch or damage your house in the process as you would be carefully setting each one down individually.
Now imagine moving as many bricks as you could carry at one time. Moving several bricks at a time would require a lot more work and generate more heat (sweat), but take less time. You would also cause some damage to your house in the process, by scratching walls and maybe damaging the floor when dropping them.
Now imagine trying to move ALL the bricks from your driveway into your living room instantly. It would require an enormous amount of energy to be applied in an instant and generate an enormous amount of heat, which would probably be similar to a bomb going off to move that much mass instantly. It would also destroy your house in the process.
Charging batteries is like moving electrons instead of bricks and moving them into our battery instead of your house. Maximizing the number that can be moved at a time is a delicate balance between applying the right amount of energy, dissipating the heat, and not damaging the “house” in the process.
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