Tesla's Battery Cell Technology Acquisition: Maxwell

Cosmacelf

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This morning, Tesla announced it was acquiring Maxwell, a super capacitor manufacturer for about $200M in an all stock deal. I've already seen some reporting of this getting it all wrong, so here's my take.

This isn't about the super capacitors. This isn't about acquiring talented research scientists. It is all about the battery cell manufacturing technology that Maxwell has successfully transferred from their super capacitor manufacturing. This manufacturing technology (note, no new battery cell chemistry breakthroughs are here at all) allows any lithium ion cell to significantly increase:
  • Energy density
  • Power output at high energy capacities
  • Longevity
And it can do all three of the above simultaneously while being significantly cheaper to manufacture. Here's the Maxwell paper that describes the results.

A lithium ion battery is simple in concept. You start with an aluminum sheet that acts as the cathode current collector. You create the cathode by mixing a bunch of elements together (nickle, magnesium, cobalt, etc.) along with a liquid solvent to form a slurry paste. You then compress this slurry onto the aluminum sheet through high pressure rollers. You then dry the new composite sheet in an oven and drive off the liquid solvent. You do this process again, this time with a copper sheet and your anode material (typically graphite with some silicon these days), and then you combine these two composite sheets together along with a polymer separator and you've got a battery cell (view this for a really quick overview).

The liquid solvent adds challenges in that it interacts with the cathode and anode chemistries in undesirable ways. And it is expensive since you have to heat the composite in giant ovens and recover the driven off solvent vapor (can't vent into the air!).

What Maxwell claims to have is a process to mix and bond the cathode and anode ingredients WITHOUT needing a wet solvent. They use some kind of proprietary polymer binder and a dry process. So the end result is a better performing cell, in every which way possible (energy density, power density and longevity), AND it reduces manufacturing cost since you don't need high energy drying ovens and solvent recapture systems.

So, what's this mean? I think this means Tesla got a bargain for $200M in stock. Gotta scoot, more later.
 
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Cosmacelf

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Time for speculation. What does this mean for Tesla, Rivian and the EV industry?

Does Maxwell have a patent on their process? Probably. This is something they developed a while ago for manufacture of their proprietary super capacitors (Maxwell is a super cap industry leader). This means Tesla has a lock on this technology for a while.

Is this a game changer? Kinda. First, this is just one of many possible battery cell improvements that the entire industry is working on. I’m sure LG Chem has good new stuff too. Second, this changes a fair bit of the cell manufacturing process. It is unlikely you’d want to retrofit an existing line with the tech until you’ve amortized the capital costs of the giant dryers, solvent recapture and wet mixers. But you’d want to use this on new lines. But maybe after you had built and proved a demo line first! So maybe this tech would see the first production cell exit a factory in 2 years? Maybe 1.5 years?

What does this mean for Panasonic as a battery cell supplier for Tesla? I think it’s time to read those Panasonic supplier agreements squirreled away in the Tesla 8-K statements. Tesla is well known for ditching suppliers and doing stuff in house if it sees a good reason to do so. If Panasonic doesn’t give Tesla a good reason to stick with them, Tesla may end up being the world’s biggest battery cell manufacturer in 5 years.

What does this mean for Rivian and other EV manufacturers? I think they had better hope that Panasonic, LG Chem and Samsung continue to innovate because Tesla is chasing them down. Tesla is unlikely to sell cells to the industry for the foreseeable future if they start making cells in-house.
 

Cosmacelf

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BTW, some people are wondering if the ultra cap part of Maxwell is of use to Tesla, especially since Maxwell recently inked a supply agreement to Geely for their hybrid cars. Ultra caps ARE useful for hybrids that have small (or non-existent) batteries. They are used to store braking energy and release it back upon acceleration. But if you have a big battery, ultra caps are useless since you'd just store the braking energy into the big battery. Essentially, the small batteries of a hybrid can't accept much power (can't stuff too much energy at once), so you need an ultra cap. Tesla will never need this.

And as far as ultra caps replacing batteries are concerned - well, right now, ultra caps can store about 1/70 the amount of energy as a battery in the same volume. At much higher cost. And the energy leaks out much faster than a battery (self discharge). So, yeah, that's not going to happen anytime soon.
 

azjohn

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My guess Tesla is most interested in the dry electrode technology for the time being and later maybe a battery/cap hybrid energy storage. This could be huge for Tesla who is already ahead of everybody else when it comes to batteries
 

azjohn

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you are right it was a good video. Sean Mitchell is one my my favorite Tesla You Tubers. I have been watching some videos on Maxwell's you tube channel to get acquainted with the capacitor technology and a lot of good info
 
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