nickceo

I have been exploring ideas on getting ebike touring logistics viable.

The obvious route from what's out there today is Lithium Titanate Oxide cells - LTO.

For example Yinlong cells as well as SCib cells rave about charging a 10ah to 40ah cell in 10 mins.

My Logistics dictate that I need a 48v to 72v LTO setup that I can recharge in 10mins and keep myself on the move rather than wait the several hours I currently have to on a lifepo setup.

To keep things civilised I would need to use the EVstreet chargers infrastructure.

Question is how to charge 72v 40ah setup at 10min or less?
Battery pack when in use would be x100 10ah Yinlong cells : 25s4p for a 72v 40ah battery pack.
To charge in 10 mins I somehow need to pump in 72x40x6= 17'280 Wh
Any charger of reasonable size is well under that figure and £££$$¥¥€€
One idea was that I can rewire the cells prior to charging so that the 100 cells become a 100s1p at ~240v DC. Perhaps flipping over the "battery pack" box cover coukd make this reasonably practical(reverse of box cover(top& bottom) would be different pattern to achieve 100s1p ...)

The question is what can I do to make myself life easier and EV Street charge an LTO ebike in 10mins!

If 17kw is too much than what's the best that can be achieved with the least extra charging hardware, weight ...

Doc_Wui

Wow. These are new to me. These?
https://www.osnpower.com/super-long-...-10ah_p26.html

A 25S4p, at 510 grams per cell, is 51Kg or 112 pounds. A 20S-10P pack made out of 200 18650 cells will be 72V36AH and the cells at 49G each would weigh22 pounds, but of course, these cell have shorter life. I guess you've done all the tradeoffs. You couldn't carry two of the lighter packs anyway.

As far as charging 10 minutes to replenish 40AH requires 240A from your charger. I see your problem, Even if you had the charger, the connector is probably as big as a soccer ball.

You could build 4 separate 25S1P packs and put them in parallel to run the bike. Then you break the parallel connection and put them in series. Now you only need 60A. You need the transistors on the BMS able to withstand 4X their normal voltage. probably 400V to be safe. The other problem is you're dealing with lethal voitages when your get close to 100volt DC. This has to be done with heavy duty switches. If someone has to move straps by hand and clamp them down with a wrench, someone could easily get killed. Mayne your lid idea could do thiis safely. Anyway, all of this has been figured out for electric vehicles, where 50 pounds is nothing. You'll have a challenge making it small enough for a bicycle.

People do ebike tour with lower voltage motors and spare packs, but I guess they only go about 60-80 miles per day.

nickceo

That site has covered LTO cells pretty good and is a great point of reference.
The reason why I considered the 10ah cells instead of just going with a 30ah cells or above is so that I could
get the rewiring effect and present 100s1p at 240v DC. Thinking was that by being able to rewire close to 240 DC(higher voltage) there might be a benefit on the charger gear needed Vs charging 25s4p with a football size plug
The Type 2 AC chargers apparently most popular currently in the UK are AC 7kw max -240v.
The Rapid Street chargers (some 50kw) are DC with voltages exceeding 240v DC and perhaps 500 DC?!
30ah LTO cells have better energy density Vs volume and weight advantage over 10ah cells but I do not get the option to rearrange them in a 100s format...
Following the original idea I could go on and choose even smaller capacity cells to reach a cell count that when rewired would get 500volts DC and then get myself in the "EV street- DC Rapid chargers".
500volts /2.4v a cell ~ 210 cells
I guess 5 ah LTO cells arranged in 25s8p and rewritable before charging as 8 25s1p for a 500v DC to the charger is what I would be looking at.

My current setup is two batteries 13s4p and a 13s3p with 18650 cells so the merits and advantages over LTO cells isn't lost on me.
It's the touring aspect of Street EV charging in 10min(or as close as I can get to it) that matters more now.
12kw-17kw, 500v ... I do remember that when Edison was pitching his DC vision of the electrical grid he specifically demonstrated that DC was safe while Tesla's AC was lethal and he used some pigeons to validate his point. Not going to base myself on any of that but was just hoping to figure out the DC to DC charging option and whether it could be of benefit (weight,bulk).

I am wondering here if the idea of going with 5 ah lto cells to get to 500v DC where the rapid chargers(DC voltage) operate would give me advantages over the soccer ball size problem
The spec sheet on the lto cell says <=1mOhm resistance and I would essentially be looking at 200 cells in series hooked up to 500v DC and some 30amps. What would the cells resistance have to be capable of and is there a way to test with a lower scale version 5s1p test at 12v 30a perhaps??

and they do that with the fine knowledge that we have all the power an ebike needs available to us on a growing network of public EV Street chargers.
It's good reward worth figuring out.

We also have a healthy cycle of news about upcoming battery tech and it's some of it will no doubt start getting to customers.... that tech is going to face similar challenges too.

For here and now it's LTO's 10 min full charge that is promised but unattainable on an ebike!