GM’s New BT1 Electric Vehicle Platform Is Not Unibody Or Body-On-Frame43
GM’s transition to an all-electric lineup is bringing a wealth of new technology and engineering to the fore, including the development of new vehicle platforms to underpin a deluge of new GM EV models. Among these is the GM BT1 platform, which, according to GM is considered neither a unibody platform, nor a body-on-frame platform.
During a recent interview regarding the new Chevy Silverado EV between GM Authority Executive Editor Alex Luft and GM Chief Engineer, Battery Electric Trucks, Nichole Kraatz, Kraatz was asked about the Silverado EV’s underlying architecture, which was confirmed to be the BT1 platform. When asked whether BT1 was considered body-on-frame, rather than a unibody architecture, Kraatz responded by saying:
“It is not a unibody and it is not a body-on-frame. We’ve designed a different type of architecture where we have a body that has a floor, but also, the Ultium battery structure is actually a good portion of the structure and those two are connected after the body exits the body shaft. So we’ve defined kind of a new category of vehicle that doesn’t have that traditional body-and-frame approach.”
When asked if there was a specific term to describe the BT1 architecture, Kraatz said that she “actually used the term UltiBody to my team the other day because we have yet to assign one.”
To note, the “Ulti” prefix is a reference to GM’s Ultium brand, which includes the GM Ultium battery and the GM Ultium drive motor tech.
The GM BT1 architecture underpins GM’s battery-powered pickup trucks and SUVs, including the Chevy Silverado EV, GMC Sierra EV, GMC Hummer EV, and the forthcoming all-electric variant of the Cadillac Escalade.
Conversely, GM’s new BEV3 platform is used to underpin the automaker’s all-electric crossovers and sedans, including the Cadillac Lyriq, Cadillac Celestiq, Chevy Blazer EV, and Chevy Equinox EV.
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Lol it’s body on frame. Can name brand it whatever you want.
Only that it’s not.
I had extensive talks with GMC Hummer EV engineers earlier this month about this. The battery slides into the bottom part of the body. That’s a significant distinction from body on frame, when the two are joined together top to bottom.
Neither of the BT1-based vehicles available currently drive like a body-on-frame vehicle, but like something very different.
It’s unibody. Can the body move independently of the frame???? That’s the key. No? Ok, their one-uni-body. End of discussion. If the Ultium platform isn’t unibody, than neither is the traverse, as it has additional “framing” on its floor for towing rigidity.
Is it space frame? That’s a whole new question. Can you remove all the body panels (including the floor) and it drive all by itself? (Not leagally of course) the corvette and camaro are space frame and are still functional “naked.”
BOF vehicles are considered superior off road and hauling simply because the frame can bend independently from the body. Can the ultium chassis twist without damaging the body? If no there’s your answer.
“can the body move independently of the frame”… Are you under the belief that a pickup truck cab, or Tahoe cabin can move around on their frames?
Body-on-frame, literally means body on frame. The EV skateboard platform is like a conventional truck ladder frame, and the vehicle body sits on the skateboard. Much like a truck bed and cab, or SUV cabin, is bolted to the ladder frame.
Too many people believe because the bed of a truck is seperate from the cabin that this means body in frame. That is not what it means. Once again: it is literally in the name.
The construction of the Hummer is closer to a defined unibody vehicle than a Silverado. But it is still a BOF.
Yes. FYI, the frame on a BOF SUV like the suburban, pickups and jeeps allow several degrees of frame flex without the body moving or sustaining damage.
Go under a Silverado, you’ll see the cab isn’t bolted directly to the frame but rather is suspended on rubber isolation mounts, and in some cases, hydraulic mounts.
Research the ford unibody truck and you’ll see whyBOF is superior for haul vehicles.
Back to the hummer EV, does the frame allow for several degrees of flex? Is the body isolated from the frame? No? Unibody.
A very accurate description of present BOF.
Remove the body from 99% of front wheel drive cars, CUVs and the engine and rear wheels fall down and are not connected(4wd drive shaft excluded) that is unibody. Most of the BEVs use the battery as a “skateboard” to rest the body on. In many ways this eliminates the labor end in the factory by allowing the skate to be preassembled before shipping.
Not the BT1 platform.
But even with a “skateboard” is the body an independent member???? That’s the critical questIon with EV trucks. Most EV’s that even are skateboard are unibody in an attempt to save every ounce to keep their colossal weight down.
Funny cause Andy Oury, Lead Engineer for the team that developed GM’s Ultium battery pack platform called it a BFI or Body Frame Integral platform.
Wow gm is so innovating what a time to be alive.
Ok, from the horses mouth, united body and frame, unibody…. Thier just to scared to admit it.
The battery tray is a very heavy load. This EV concept is a total game changer. I would love to see some videos of Hummer impact testing and crash crunch areas. We are in very interesting times.
This thing ONLY weighs in at a “claimed” 9000 lbs. That’s around 2000 lbs. more than a Diesel-powered, long-bed, crew-cab, 4WD Dually 1 ton pickup ! Wonder how many older lifts in car repair shops can handle that weight ? Accessing that battery pack for the eventual needed replacement should be fun…..
The GM battery packs should run close to 500k miles before needing replacement so at that point the vehicles will be obsolete.
Have never seen this 500k stated anywhere
What’s your source??
I’ve not seen that number, but here is what I’ve found
“Tim Grewe, GM’s Global Electrification and Battery Systems Director, told Car and Driver that the Ultium pack does not suffer capacity loss from excessive DC fast charging, so GM will not advise users to charge the pack to less than 100 percent. He also promises that the Ultium pack will last longer than that used in the Bolt EV—between 150,000 and 250,000 miles in real-world usage.”
Thank you ma7mgte:
My next question is what is the cost for a removal and install of an Ultium pack if life is estimated at between 150K and 250K miles.
As an example, I have a Suburban currently with 539,296 miles on the clock, a 6.5 iron block and iron heads diesel with piston underspray for cooling, cleaning and lubrication. Original block, engine heads and internal guts.
So, given a hypothetical analysis if I had a GM EV with Ultium battery tray, I would be replacing it 3 X’s now. What is the battery tray and R & I cost?
With Ultium they don’t need to replace the whole pack or tray. You can go by module.
Also by the time these packs need replacement you will likely have more energy dense and cheaper packs/modules available.
We can’t really guestimate the prices now as Ultium is just coming to market.
GM also has an 8 year 100k Mile warranty.
Terrible idea. Replacing just 1 pack or module will strain and cause early failure of the remaining modules. You need balenced charge-discharge.
Each module of the Ultium pack has it’s own wireless BMS makes it much easier to balance.
So we have two GM engineers who can’t come together to decide what to actually call BT1 from Andy Oury & Nichole Kraatz? Sounds like certain things are left out of the meetings that is essential before the media catch them off guard.
They probably think micro fiber should be on mirror covers also.
There is an engineer named Andy Oury and you know that I was not talking about you right? And do you recall that I don’t want to have anything to do with you so why are you replying to me when I stated that I did not want to consult with anyone who does not know the difference between “your” and “you’re”. Obviously you are very forgetful and hardheaded.
I’m forgetful says the guy who believes micro fiber mirror caps would help Cadillac sell cars lol. Also I’m waiting on my apology from when you falsely accused me of using your name. It would be nice for you to admit you were wrong but of course you can’t do that.
And you still replying to me still? I know you like to stalk me Andy because you have no morals, integrity and defame anyone who show you up.
Hmm I believe the correct term is I’m the one living rent free in your head. After all you wrote a whole page worth of how I supposedly used your name blah blah. I’ve begun to notice a pattern with you lately, you say something then get downvoted to hell then say something else and what a surprise the same thing happens again.
You are a perfect definition how a stalker behaves. You know nothing how I post and you can’t form proper sentences and don’t know the differences between two words. You are the biggest joke and a hypocrite on here. I still say that you are a sociopath who loves stalking people who is far more advance and intelligent than you are, loser.
And you still replying to me still. Lol who can’t form a sentence? Pretty cool to learn you are a psychologist.
You are right. It is cool to be a psychologist as a profession while it is not cool being a stalker loser like you? How many people had committed suicide because you?
That’s really the best you could come up with? You disappoint me. I know you heard that a lot growing up so I’m sorry to bring up old memories but it’s true I just expected more from you. Also it’s you’re right.
It is a hybrid set up using a bit of each former tech for a new platform that contains a battery.
Are there not enough politics to argue about already?
Yeah, why is this even being discussed? GM will call it whatever it wants and just another J Lo filler article! It’s amazing what one will write about when their is nothing to write about, I guess it’s better than car wrecks?
GM has no business trying to make consumer vehicles…
Who Killed The Electric Car? GM.
Who Killed so many Americans? GM.
What is the average life of these batteries and the cost of each, disposal, etc.?
Everyday the posts on this site reach new lows, like the one above me.
Who spent 1 billion developing an EV that was ground breaking and ahead of it’s time; GM
Who absolutely did not care, (minus 800 passionate leasee’s): consumers, including the Seriera Club where not one member leased an EV-1.
The more you know…
No need to fret, we can’t even define what a man or a woman is anymore, that makes the structure of an automobile seem less important.
Best comment I’ve read on this site…
So the logical conclusion appears to be that the Hummer is a unibody truck trapped in a body-on-frame body…shame on GM for assigning chassis-phobic names…
I guess I’m just as guilty, calling it a truck just now…I apologize to all Hummers and any others in the EV community that I may have offended…I need to work to become a better automotive enthusiast. I hope that additional dealer markups will help in the healing process.
Hummer can identify as an European sports car (or anything else it wants)…
The average battery life of a new (2020 on-) is over 300,000 miles, for these reasons;Larger battery range 250milesx 1000 cycles minimum = 250,000 mile battery. Then after that the battery is still working just that range has decreased to 200 miles range. By then the battery is still valuable as a second life storage for home or grid use. Then it is a gold mine of recycled nickel, cobalt and lithium that will be reused in future batteries.
Unless it’s a Bolt battery.
There really should be a limit of 2 comments. I enjoy reading GM-related news. But their are a bunch of children on this site. Really if you’re not a gm consumer troll somewhere else.
Who is speaking this time? Is it why we’re trump and epstein such close friends, or andy, gurt, ken, the fake k4cksaw, shane, shawn, or one of your many many other trump names? Which personality did you choose for this comment?