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Hummer Battery Pack Breakdown (Munro)

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Check out this channel's breakdown of the HUMMER EV Battery. These two seem to know what they are talking about and they say "inefficient", no "cost-effective", "unusual" so many times. The battery pack has a significantly high number of welds and a very interesting layout in terms of cooling. At the end of the day, no of this matters since the battery has a long warranty but I couldn't wonder but think if this product was rushed to market.
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Check out this channel's breakdown of the HUMMER EV Battery. These two seem to know what they are talking about and they say "inefficient", no "cost-effective", "unusual" so many times. The battery pack has a significantly high number of welds and a very interesting layout in terms of cooling. At the end of the day, no of this matters since the battery has a long warranty but I couldn't wonder but think if this product was rushed to market.
They probably have a version one pack... not version three with refinements... also it was built for strength in mind and it may be unusually built it in a way that is cheap in the long run... some items may not seem it. Also merging with my thread.
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They probably have a version one pack... not version three with refinements... also it was built for strength in mind and it may be unusually built it in a way that is cheap in the long run... some items may not seem it. Also merging with my thread.
Yes that does make sense. The people in the video didn't talk about fire resistance. I remember early Tesla's catching fire so easily. I'm sure GM wanted to avoid such negative publicity, the type Elon seems to thrive on unfortunately.
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Holy packs, Battman! A lot to 鈥漸npack鈥 from this video! They missed some critical aspects for why things are as they are, but also revealed a few surprises. I have other commitments the next two days, but will get back soon with my own insights. One for sure. Yes, definitely a gen 1 pack w/ the flawed pack lid sealing design.
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Comparing the materials used in the Lightning versus the Hummer, aluminum versus steel, is apples to oranges. Lightning is body on frame, so does not need as rigid a battery pack, also not really an off road beast. Do you really want to be rock crawling with an aluminum pack?

Good to see they are cooling the contactors, this was a failure for Ford on the Mach E.
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Negative from the start.

Throw in a passive aggressive comment about target audience.
"Tactical"... Surprised there was no political comments in there.

Shows there true fan boy colors.
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Yes that does make sense. The people in the video didn't talk about fire resistance. I remember early Tesla's catching fire so easily. I'm sure GM wanted to avoid such negative publicity, the type Elon seems to thrive on unfortunately.
LOL, Tesla is always talking about the fuses in the batteries for fire resistance, then look at what happens:


Maybe that low cost/low weight aluminum battery housing took a road debris hit.
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Well, this video is amazing visually, as it provides - to those "with ordinary skill in the art" - incredible insight on the Hummer pack case design, along with the Ultium module design.

Just turn off the audio and captions. I'm working on a comprehensive review this video to highlight of all the innovative engineering features incorporated into GM's new pack and module architecture, but that will take some time. Here are a few nuggets in the meantime:

re: the pack case: My summary from a previous thread still rings true - Hummer pack tech summary

re: the cooling lines: Munro's team noted correctly they are jacketed in Aramid fiber. One engineer incorrectly hypothesized the possibility it was to deal with protecting the tubing when slicing hte sealant to open the case. The other - with a thinly-vailed cut to every Hummer owner or future customer - suggested it fit the Hummer for "tactical" reasons.

The truth is very different:

This is an excerpt from the Hummer Emergency Response Guide, provided to all emergency responders to guide them on how to deal with crashes, fires, etc. Note the following text:

" The vehicle is equiped with a battery management system with internal fault protection, including thermal runaway mitigation. In the event of a "Battery Danger Detected" notification, DO NOT cut or disable the low voltage system unless you need to disable the air bags for occupant extrication....

"....Automatic safety systems are enabled when low voltage power is available, including a battery thermal runaway mitigation system that internally cools the High Voltage battery when a thermal event is detected; this feature is available in non-crashed, static situations."

So what is that cooling system? The glycol cooling loops. Therefore, the glycol cooling loops inside the pack case must be protected at all costs from extreme high temperature thermal damage during a thermal event. What is Aramid's most famous product? Nomex

I'm betting this thermal runaway mitigation feature will likely be standard and appear in every Ultium pack ever torn down, from Equinox through Hummer and Brightdrop.

One last nugget: The module cell-group separator: The teardown revealed an unusual separator between each three-parallel-cell group, that contained multiple foam pads and stainless steel plates all encased in a plastic jacket. As well, the module case edges were lined with it. One engineer described the foam as a "talced polypropylene" and puzzled about using stainless plates.

The truth is very different:

Pyrothin

Starting at only 2mm thickness, our thermal runaway barriers can be tailored to perform in critical applications, including:

PyroThin庐 is a thin, lightweight, high-temperature thermal insulation and fire barrier engineered to mitigate thermal runaway propagation at cell-to-cell, module, and pack barrier level. PyroThin鈥檚 aerogel technology evolved from two decades of thermal protection development in energy infrastructure, chemical processing, and transportation applications, including internal combustion engine (ICE) and electric vehicle (EV) platforms.
  • Cell-to-cell thermal runaway propagation
  • Battery pack and module barriers
Using just lightweight aerogel foam pads + thin stainless backing plates, GM created 1000 deg. C-rated fire walls between every three- cell group. And that foam serves double-duty as the compression pads required to be place between cells in every pouch-cell-based module. Plus the 1,100 deg. C-rated stainless plates (aluminum would fail at 400 deg C) provide rigid support for the high-temp gaskets GM uses at the top and ends to isolate and seal fire-encapsulated cell groups from each other, directing TRE-generated hot gas vents out that cell-groups mica-sealed top ports preventing hot-gas migration to adjacent cell groups.

FYI, Aspen presented Pyrothin at a session at last fall's ChargedEV's free and online EV Engineering conference, and it was specifically noted then that it had been selected by GM for use their Ultium modules. This application was no "secret".

With a quantum leap from their disastrous experience with the Bolt, GM has gone all-in on providing state-of-the-art best-practices for thermal runaway management within their Ultium packs. Safer NMCA chemistry. Better BMS, emergency situation glycol cooling. Cell group firewall isolation and sealing. Mica venting for each cell group. Case venting for each module. High strength steel module cases. All to turn an increasingly-unlikely TRE occurrence into an error-message and a pack replacement situation, not atotally-involved pack fire and vehicle replacement or worse.
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The truth is very different:
So it IS tactical.
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With a quantum leap from their disastrous experience with the Bolt, GM has gone all-in on providing state-of-the-art best-practices for thermal runaway management within their Ultium packs. Safer NMCA chemistry. Better BMS, emergency situation glycol cooling. Cell group firewall isolation and sealing. Mica venting for each cell group. Case venting for each module. High strength steel module cases. All to turn an increasingly-unlikely TRE occurrence into an error-message and a pack replacement situation, not atotally-involved pack fire and vehicle replacement or worse.
I would love to know if GM actually tested this by shorting a set of 3 parallel cells in a complete battery housing, just to see how effective it is. I assume they did this, would be interesting to see a video of the result.
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I would love to know if GM actually tested this by shorting a set of 3 parallel cells in a complete battery housing, just to see how effective it is. I assume they did this, would be interesting to see a video of the result.
I'd bet on it. This is a primary life-safety issue that deserves at least same level of real-life testing simulations as the various crash testing. Probably set up a separate section of their lab specifically for first testing small prototype cell/containment sub-assemblies, then expanding to full modules and packs with real-life induced TRE events during the development process. At the pack level, there are special pressure vents that also have to work, plus test that the pack cases adequately maintain their integrity under TRE conditions.

And yeah, that would make a great video.
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I would love to know if GM actually tested this by shorting a set of 3 parallel cells in a complete battery housing, just to see how effective it is. I assume they did this, would be interesting to see a video of the result.
IIRC they do stab testing as well. Batteries are supposed to handle a puncture without having a thermal event.
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IIRC they do stab testing as well. Batteries are supposed to handle a puncture without having a thermal event.
I have done pellet gun tests with old RC batteries, but forgot to video it.
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IIRC they do stab testing as well. Batteries are supposed to handle a puncture without having a thermal event.
Well, for LFP cells, I've seen nail puncture demonstrations to show how inherently safe they are as compared to NCA, NMC and many other LiON cells. One common way of intentionally triggering a TRE in high-nickel cells during lab tests is to fire is sharp metallic object into the cell electrodes. There are even research papers on the "optimized" nail for triggering a TRE when testing cells. A nail puncture creates a cathode/anode dead-short, which guarantees a short-term major heat event from the ohmic heat of the dead- short amps. It is only with a more-stable cell chemistry that the anode/cathode/electrolyte's don't hit ignition point and take off when subjected to that heat event.
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Well, for LFP cells, I've seen nail puncture demonstrations to show how inherently safe they are as compared to NCA, NMC and many other LiON cells. One common way of intentionally triggering a TRE in high-nickel cells during lab tests is to fire is sharp metallic object into the cell electrodes. There are even research papers on the "optimized" nail for triggering a TRE when testing cells. A nail puncture creates a cathode/anode dead-short, which guarantees a short-term major heat event from the ohmic heat of the dead- short amps. It is only with a more-stable cell chemistry that the anode/cathode/electrolyte's don't hit ignition point and take off when subjected to that heat event.
I know from experience that LiPOs ignite when punctured, had a screw puncture one in an RC plane, only ashes left. The pellet gun test results in the same thing, once exposed to oxygen, up it goes.
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Maybe GM hired some ex-Boeing engineers to help with this. If you remeber the 787 LiON fire, it was all contained within the stainless steel container. The aircraft survived the event, which is what is supposed to happen.
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