Tesla Semi Battery and Charging configuration

[henderrj]

Having had some success in these forums as a prognosticator thought I'd slide out a bit further on the limb.

I believe the Tesla Semi will have multiple passenger vehicle battery packs - probably model 3 packs and certainly a minimum of four of them. Eight seems more likely. But they will be in pairs - because ...

Charging will use multiple supercharges. Diesel trucks fill from both sides, Tesla semis will likely have 2 or even 4 connectors. The driver would plug in as many as he wanted to pay for (not sure they'll charge a fee for multiple connections but they might). If a truck pulled in and used 4 superchargers configured identically to what we have today he could see 480 kW charging. It is maybe more likely that Tesla will add semi specific charging spots

Tesla would, then, have to make a BMS that can manage multiple charge inputs (likely isolating them one from another) and routing the current where it needs to go. "Pack balancing" would extend to equalizing of different packs. This is no small task but I think this would be overall a much simpler approach to the problem, just as using "a bunch of Model 3 motors" is the best way to achieve the power needed.

Okay, neck extended - anyone have a guillotine?

 

[jaguar36]

It won't use 3 packs. It will likely use the same or very similar modules, but there it doesn't make sense to use packs from a 3. The pack is a structural member, and its highly unlikely that the structure of the pack could be fully utilized in a semi. Would make far more sense to just have a unique Semi pack (or multiple ones.

Tesla Semi will have its own superchargers. I doubt they will be compatible with the cars, although maybe the much rumored 350kW ones will be, who knows. It could have multiple connectors, but it seems more likely that it would just be a single large connector. Doesn't really matter though.

 

[Haxster]

It's hard for me to imagine a semi fitting in a current passenger car supercharger station...even if it's not pulling a trailer. I guess it could if it dropped off its trailer(s) nearby while it was charging. More likely, semis will have their own chargers or battery swapping stations.

Swapping stations on long haul routes could make sense. Fast, in cheap real estate, and only limited services needed. (Large trucking companies could even have their own network of swap stations). Then the truckers could use any regular truck stop that provides services to ICE trucks.

 

[MorrisonHiker]

It's hard for me to imagine a semi fitting in a current passenger car supercharger station...even if it's not pulling a trailer. I guess it could if it dropped off its trailer(s) nearby while it was charging. More likely, semis will have their own chargers or battery swapping stations.

Sure they could fit. They would just have to park perpendicular and take up all the spots and Superchargers! Imagine this was a semi instead:

I'm kidding, of course.

 

[henderrj]

It won't use 3 packs. It will likely use the same or very similar modules, but there it doesn't make sense to use packs from a 3. The pack is a structural member, and its highly unlikely that the structure of the pack could be fully utilized in a semi. Would make far more sense to just have a unique Semi pack (or multiple ones.

Tesla Semi will have its own superchargers. I doubt they will be compatible with the cars, although maybe the much rumored 350kW ones will be, who knows. It could have multiple connectors, but it seems more likely that it would just be a single large connector. Doesn't really matter though.

Of course, we agree that it's likely to be a separate charger for the semis. I still think we'll see multiple connectors though. There are, of course, designs that can allow a thousand kilowatt throughput. I've got a patent on one myself. But it doesn't sound like Tesla is going to do that.

As far as the packs, how would they be structural in a semi? I really don't think that's going to happen and I think the existing packs would fit beautifully between the rails. But then again, I've been wrong more than a few times!

I didn't add that the battery packs could be put in the trailers themselves. There's no reason at all not to do that. This would make the range better and, of course, the need for multiple connectors greater.

 

[henderrj]

It's hard for me to imagine a semi fitting in a current passenger car supercharger station...even if it's not pulling a trailer. I guess it could if it dropped off its trailer(s) nearby while it was charging. More likely, semis will have their own chargers or battery swapping stations.

Swapping stations on long haul routes could make sense. Fast, in cheap real estate, and only limited services needed. (Large trucking companies could even have their own network of swap stations). Then the truckers could use any regular truck stop that provides services to ICE trucks.

Agreed, it would be difficult to shoehorn a semi into their. But the idea is there. Just widen them a little and they become multi-use systems.

I think battery-swapping would be wise, I just don't think it'll happen. It's just too easy to put a lot of batteries in a semi and a, especially, in its trailers.

 

[jaguar36]

As far as the packs, how would they be structural in a semi? I really don't think that's going to happen and I think the existing packs would fit beautifully between the rails. But then again, I've been wrong more than a few times!

As I said, its unlikley that it would be, which means you're wasting a fair bit of weight using a 3's pack on a Semi.

The reason you wouldn't put packs on the trailers is because the trailers are generally considered separate units from the tractor unit, frequently owned by different people and completely interchangeable. If you put packs on the trailer you'd have to track all that, they'd have to be special trailers, and so on.

 

[Haxster]

Another future concept to think about...

With small efficient electric drive motors, modern controller electronics, and powerful batteries, maybe the traditional tractor-pulling-trailer approach will make less sense.

Semis already control a trailers brakes and lighting. What about having them also control their electric drive motors and then stuff some humongous batteries on their underbelly? And think about the safety/efficiency benefits of using trailer regenerative braking.

 

[henderrj]

As I said, its unlikley that it would be, which means you're wasting a fair bit of weight using a 3's pack on a Semi.

The reason you wouldn't put packs on the trailers is because the trailers are generally considered separate units from the tractor unit, frequently owned by different people and completely interchangeable. If you put packs on the trailer you'd have to track all that, they'd have to be special trailers, and so on.

the logistics would, indeed, be horrific. But Tesla said they are talking to specific shipping companies. Perhaps some who use their own trailers. Container haulers might do that, but i'll admit i am not sure about that. Still, as Haxster says, the benefits are there!

 

[henderrj]

Another future concept to think about...

With small efficient electric drive motors, modern controller electronics, and powerful batteries, maybe the traditional tractor-pulling-trailer approach will make less sense.

Semis already control a trailers brakes and lighting. What about having them also control their electric drive motors and then stuff some humongous batteries on their underbelly? And think about the safety/efficiency benefits of using trailer regenerative braking.

i hadn't thought of putting motors in the trailers. you might have an idea there. if brakes can be controlled carefully enough why could motors? But, as with the batteries, the logistics get interesting. same solution as above would work, until EV Semis become ubiquitous.

 

[Haxster]

i hadn't thought of putting motors in the trailers. you might have an idea there. if brakes can be controlled carefully enough why could motors? But, as with the batteries, the logistics get interesting. same solution as above would work, until EV Semis become ubiquitous.

And beyond (well beyond) self-powered trailers, there could be self-driving trailers. No semis (or drivers) needed.

 

[arnis]

There are many ways to solve the puzzle.
In case of charging: either big enough battery for maximum time (full speed full load) truck driver is allowed to
drive, plus small buffer and recharge speed according to resting cycle (driver sleeps). No need for extreme high
power as charging can happen during many hours.
Or less battery on board and more charging spots. Though in case of EU truck driver must have some longer uninterrupted
cycles as well. 4h drive 1h rest non-stop is not accepted.
Or shorter run vehicles (supermarket food distribution etc) that run the same route daily: from some warehouse (with charging capability for the night) to a dozen of nearby malls during the day. Back to base to recharger. Exact amount of battery on board can be estimated for BEST results. In case of city only driving, Reduction gear can be adjusted for low-speed scenarios for better efficiency.
Tesla's SuperCharging network is flexible. Chargers and stalls are separated.
That means some excising places are fine for new, differently positioned "truck stalls" that work on those same chargers cars use. Though truck drivers have their routes and places to rest. I expect mostly truck dedicated places (with some car stalls as well, same chargers, cost savings).

First adoption step for EV trucking will likely not be trailer semis. But rather one-piece machines (easier to distribute battery mass). Electric trucks have more benefits in cities. And likely cheaper at the beginning (same was with low range EV's years ago).
After charging network matures this can extend to long-haulers.

 

[Brando]

Just like Model S start at the top of the price range and then down scale [i.e. not start at the bottom and scale up]
(and Model 3 for that matter which is why the expensive ones first, then down scale to the cheaper)

Seems clear now, right?