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Tesla to Buy Energy Storage Firm Maxwell Tech at $4.75 a Share
- stcredzero 8y agoHere's my first thought: Put both supercapacitors and batteries in an electric car. The supercapacitors can help greatly in a couple of ways. When doing a fast charge, the supercapacitor bank can absorb the energy super fast, much faster than a bank of batteries could. Then a microcontroller could control the transfer of that power more gradually over to the battery. (Unfortunately, super capacitors, when I last read something about it, could only hold their charge for 4 days or so, so they couldn't replace batteries themselves.) Perhaps this could be the key to the 5 minute recharge for cars? Second, supercapacitors could also save some wear and tear on the batteries during rapid acceleration and regenerative charging.
- kevin_b_er 8y agoFor this to work you'd need as much capacity in supercaps as in batteries. In that case you'd want to use that capacity, except it self-drains. The UX would be strange and difficult to manage. EDIT: The above comment was meant about supercharging, not regenerative braking.
- throwaway5752 8y agoNo it wouldn't! You could preferentially store the regenerative braking energy into the ultracapacitors (and discharge from them from a stop, instead of the main battery). You're not talking a huge number of them (order of magnitude of ~100) for a cycle brake cycle at Model 3 mass, highway speed, and normal braking.
- LeifCarrotson 8y agoYou wouldn't need an equivalent capacity in supercaps as batteries, only as much as the vehicle can use or create in a short amount of time. The UX would be invisible: If demand is greater than the supply available from the battery pack, drain some energy from the supercapacitors. If it's less, gradually shift some energy into them. If the driver is not in the vehicle, drain it all out, when they come back, recharge the supercaps. The problem is that these capacitors and transfers add cost money, space, weight, energy, and complexity. Looking at some numbers, batteries are ~20x more energy dense in both volume and weight. Batteries have 1/10th the power density, but efficiency drops significantly with discharge rate and they have fewer lifetime charge cycles and poorer temperature response. Batteries also have much, much lower self-discharge, and cost a lot less per kilowatt-hour. Right now, lithium-ion batteries are simply good enough and supercapacitors are not that much better, so it's the cost-benefit analysis says it's better to take the costs you would have spent on supercaps and just put in a few more batteries. That balance could shift, though, with improvements in supercap technology, or - paradoxically - with improvements in battery chemistry. If a battery with much better energy density and/or lower cost was found, with a reduced discharge rate that was sufficient to cruise but insufficient to accelerate or do regenerative braking, you could add supercaps to make a vehicle based on that battery feasible. It's similar to the electric grid - the base load would be handled by the slow batteries, similar to coal or nuclear power plants, while peaking loads would be handled by the supercapacitors, like a gas turbine.
- kevin_b_er 8y agoI agree this could work with regen, but not for "supercharging".
- spectrum1234 8y agoThis is an interesting idea. Is this really possible though? Is it just a cost challenge? I admittedly haven't read up a ton on fast charging options but I also don't think I've seen super-capacitors mentioned as an intermediary source in any discussions. Given the article mentions Maxwell wanting to get into the automotive industry, a fast charging use is probably still a long ways out at this point.
- flexie 8y agoHow much space would sufficient supercapacitors require and would they be heavy? Would it add significantly to the cost of a car?
- joseflavio 8y agoIt seems they are quite light, at least according to this guy who built a home-made hybrid car battery using super capacitors: https://www.youtube.com/watch?v=VJhJ5TfQ6DU https://www.youtube.com/watch?v=VJhJ5TfQ6DU
- Scoundreller 8y agoOr could they even be structural and offset some other components’ weight.
- toomuchtodo 8y agoTesla just filed a patent for a new battery chemistry out of their Nova Scotia R&D facility that supports faster charging and superior longevity. I expect batteries to become supercapacitors faster than supercapacitors become batteries. If supercapacitors have any role, it’s at EV charge stations to reduce demand charges from utilities. VW just agreed to buy a whole lot of Tesla batteries for this purpose at their Electrify America charge stations. Space is not an issue, as you can bury your storage under the charger stalls.
- solarkraft 8y ago> If supercapacitors have any role, it’s at EV charge stations to reduce demand charges from utilities Especially here I'd expect batteries to win out as transfer capacity is roughly proportional to storage capacity with batteries.
- Symmetry 8y agoFor a capacitor to be used in charging that way it would have to have something like the same capacity as the car's battery. Supercapacitors tend to have lower specific energy density than batteries do so this would require reducing the car's range by something like a factor of 5. A capacitor much smaller than the batteries acting as a buffer for rapid acceleration and braking might make sense, though.
- briffle 8y agoI could see it used for the superChargers, so they could have more chargers feeding off a smaller power connection. (especially for the ones needed for the semi).
- newnewpdro 8y agoThis is far more plausible, where space is abundant outside the vehicle to keep a cache of supercaps to charge from. Especially if the usage pattern tends to be very bursty. But if the superchargers are (or will be) continuously near 100% utilization it's pointless, they'll need the current at the mains.
- extrapickles 8y agoI doubt they will be used for either side of charging. Super/Ultra capacitors cost a lot more than batteries per watt hour.
- hinkley 8y agoWhy not in the charge control circuitry in the supercharger? Don’t those use some pretty big caps?
- jws 8y agoIn the context of a Supercharger the critical metric would probably be cost per charge/discharge cycle for a given capacity bank. While a car probable averages a fraction of a charge cycle per day, a busy supercharger might be on the order 10 cycles per day. Super capacitors degrade more slowly than batteries with cycles. The use which might make sense is to use the capacitors to supplement the grid supplied power during the initial fast charge phase, then in the slower final charging phases or idle time recharge the capacitors from the grid for the next customer. This levels out the demands on the grid and can result in a lower electricity rate from the power company. It all depends on the constants if it makes sense. Or maybe it doesn't make sense and Tesla needed something out of Maxwell's patent portfolio.
- agent86 8y agoThe trouble spot with Superchargers is usually the end of the charge, not the beginning. The batteries can usually absorb energy rather quickly when at a low rate of charge. What is really painful is the last 10% where the charge rate drops line a stone. What would be an interesting use of this idea would be to have 10% capacity onboard in capacitors. Once you get within 10% of the desired charge level in the batteries, you quickly charge the capacitors, which then trickles into the battery over time. This might allow you to increase the overall charge rate for the car which would help reduce wait times at Superchargers.
- tedsanders 8y agoFar better would be to add 10% battery capacity, which would have the same net effect for cheaper. If you're not going to be using the high power of a supercapacitor, there's zero reason to pay a premium.
- agent86 8y agoThe trouble with that is to a certain extent we're just kicking the can down the road. Modern Tesla vehicles have more range than older ones, yet people still charge modern ones to 100% for various reasons. The idea here is to leverage their incredibly fast rate of charge and short term nature to reduce time spent Supercharging. Very roughly speaking, you can charge from 0-90% in an hour, but to go from 90-100% can take almost another hour. If you could get the car to 90% and then very rapidly charge the capacitors with the remaining 10% that trickles in, you get the car off the charger faster. In theory you could almost double the number of cars you could serve at that station.
- toomuchtodo 8y agoTesla is rolling out a firmware update that will prevent you from charging above 90% at high contention Superchargers. Simple solution.
- Dylan16807 8y agoThat's just lying to yourself about what "100%" is, by excluding the caps. It's again easier to add more battery and pretend it doesn't exist for reaching 'full charge'. That will also give you better battery longevity.
- agumonkey 8y agoI think car brands are already designing hybrid power circuits. The benefits of low resistance caps as small bursts / buffer, and avoiding wearing the usual li-ion banks is too good to pass on.
- throwaway5752 8y agoIt's interesting. Maxwell has been around for decades. Publicly they were known for ultracapacitors (non-expert opinion is that this would be a sweet spot for regenerative breaking capture in Teslas). But seems like nothing worth acquiring the company over - there are other vendors and they could just set up a multi-year supplier contract. There are some articles/rumors out there about dry electrode battery tech Maxwell was working on.
- newnewpdro 8y ago> There are some articles/rumors out there about dry electrode battery tech Maxwell was working on. If this acquisition included any breakthrough-level battery technology, it'd be for far more than $218M as it probably would have involved a bidding war considering the stated electrification plans from all major auto manufacturers.
- throwaway5752 8y agoWhy do you think Tesla acquired Maxwell, then? Why did Maxwell sell existing lines of business several months ago to focus on the dry battery tech and ultracapacitors? I don't know enough about dry battery electrode tech to know how much progress there is, how much an of an improvement they are above existing commercial technology, or who else has IP in the space. Your response seems a bit high on the cynicism/information ratio, but I would be genuinely grateful for more information about this.
- newnewpdro 8y agoI persume it's to bolster their battery tech and R&D dept. It just doesn't seem like anything obviously game-changing from where I'm sitting.
- sidcool 8y agoIn my opinion this is also a talent acquisition. Maxwell's decades of experience would be helpful to Tesla's battery ambitions.
- carlivar 8y agoCertainly more fuel for the fire with Tesla bears, given that Maxwell has been in trouble with the SEC on multiple occasions for financial shenanigans: https://www.sec.gov/news/press-release/2018-48 https://www.sec.gov/news/press-release/2018-48 https://www.sec.gov/news/press/2011/2011-31.htm https://www.sec.gov/news/press/2011/2011-31.htm
- throwaway5752 8y agoOne broken link and one article from 8 years ago about a settled FICA case? It's a $50B company acquiring a small, technically related company for $200M. I don't think even TSLA bears would care. edit: perhaps you meant https://www.sec.gov/news/press-release/2018-48 https://www.sec.gov/news/press-release/2018-48 (without the 'x')? It's never good news when there's an SEC investigation, but this seems relatively minor (channel stuffing under a Sales executive, and then a < $3M settlement by the company that it should have caught it).
- carlivar 8y agoFixed the link. I just think with all the conspiracy theories out there (which I'm also skeptical about) it is kind of amusing.
- inscionent 8y agoTry harder
- martinald 8y agoIs Musk pulling this to try and distract attention from the sales estimates in Jan 19? It's looking like an enormous, enormous plunge.
- erikpukinskis 8y agoWhat is a sales estimate? Are you talking about production targets from the shareholder letter?
- sidcool 8y ago
- zaroth 8y agoI miss the full power regenerative braking when using my Tesla in the cold. Like, I really miss it and don’t like driving the car as much when it just coasts when I lift the accelerator. I actively dislike pressing the brake pedal anymore, and feel cheated whenever I have to touch it except to activate Hold at a stop. If supercaps could give me full regenerative braking at 0°F then I’d pay an extra $1-2k for the feature absolutely. In warm climates I can absolutely see brake pads never being replaced. The only time I use the brake pads to slow down is in sub-freezing temps and once in an emergency. For those who haven’t driven an EV with strong regen braking, you drive with a single pedal. “Neutral” is the accelerator slightly depressed. Lift your foot to slow down, fully lifting your foot is a strong braking down to about 10 mph. I should look up how fast you get 60-10 with a warm Tesla on regen alone. You drive with a single pedal, and you can dart in and out of traffic very nimbly because over-accelerating for a lane change and then regen’ing back to cruising speed is very efficient and fun and you don’t have to move your foot to another pedal. But regen degrades as the battery cools. A frozen battery will barely regenerate at all, at 0°F it’s actually disconcerting when you lift your foot and the car just... coasts. The display does have a gauge showing how much regen is available, so it’s not a surprise but it literally feels weird.
- castratikron 8y agoWhy not use resistive braking to warm up the battery pack? This is how locomotives implement braking; the drive motor operates in regen and the current goes to massive grid resistors. There are no brake pads.
- toomuchtodo 8y agoThe Model S and X have a dedicated battery warmer, the Model 3 does not as a cost cutting measure (it uses the motor windings to heat the coolant loop, but it appears this solution, while clever, is inadequate).
- Scoundreller 8y agoWhy not resistively heat that cooling loop? Or release it to the cabin? Turn on the de-frost? I kinda wish my ICE car would crank everything up while engine-braking down a hill to reduce brake and fuel use. It shouldn’t be that expensive...
- jmpman 8y agoThis seems to make more sense for optimizing 0-60mph acceleration metrics than just about anything else. Using SuperCaps, a base Model 3 could have the 0-60 times of a P100D for much less than the cost of the required batteries. 4WD off road vehicles could also have much higher torque for brief periods of time.
- jseutter 8y agoWhile true, I think cold temperatures might be the more applicable scenario. When the batteries are cold, the amount of power you can extract is limited, as is the amount of power you can inject by regen braking. This is one factor that leads to crappy range in cold climates. Capacitors can smooth out the power curve - need 1000 amps of current for 4 seconds? No problem, that comes from the capacitors and the battery only sees a draw of 200 amps. Need to regen 600 amps for 15 seconds? No problem, dump that into the capacitors and recharge the batteries at 50 amps for the next minute. Knowing Tesla, they will use capacitors to offer both; a super-plaid mode that can supply 1800 amps momentarily, as well as better cold weather performance.
- jmpman 8y agoCan you market the cold temp regen? Maybe? Can you market 0-60 numbers or 4wd capability? Absolutely. Which one is sexier? I think Elon would say the performance numbers.
- HeadsUpHigh 8y agoThere is literally no reason why they have to pick between the 2. It's one system that can do both depending on the situation. Some countries/areas will care more about the cold temp regen and some other markets will care more about 4wd or the 0-60 performance. The great thing about EVs is that you can just redirect power to whatever you need at any given time.
- pdq 8y agoWhy is this newsworthy, other than Tesla is acquiring a micro cap company in an all stock offer? There's not even a blog post on Tesla.com or a tweet by Elon regarding Maxwell.
- smileysteve 8y agoBecause Maxwell is a fairly popular name in the field; and this is interesting for hackers...
- Gravityloss 8y agoThe cars already have heat pumps in the form of air conditioners. They could be designed with minor modifications to also be used for heating, improving the energy efficiency of cold vehicles a lot.
- ChuckMcM 8y agoThis is a smart move by Tesla, Maxwell's supercap technology is a really good way to moderate power needs and to extend range. It also seems like the first step in the "Okay, we have the basic system that works, lets start knocking off the biggest problems with it." mode that internal combustion cars have been doing for the last 100 years.
- robertAngst 8y agoWas Maxwell a sinking ship? I wonder what life is like for the new employees of elon. I heard it will not be good.
- leggomylibro 8y agoI dunno, I could be using them wrong but I have not been impressed with their (or any) supercapacitors. At the 1000s of Farads, they seem to bleed charge like crazy, and it gets a lot worse when they need to deal with mechanical shocks and vibrations, even the "durablue" ones. Their low voltage also makes them hard to use; you need to balance them, and their capacitances vary considerably. Most range from -20/+80% to -10/+20%, but I guess big customers have options to deal with that. Still, if your battery pack is 300+V, and your supercapacitors can only charge to 3V...that seems difficult. I used to be really bullish on them for regenerative braking - I think some kinds of buses do use them for that - but having tried to use them, I can't see them being robust enough for consumer, and especially consumer automotive, requirements in the immediate future. Also, it's on the order of 10x the cost for similar capacity to lithium chemistries, and that comes in a package that weighs on the order of 10x as much as a similar battery. But hey, I'm just a layman. It sounds like you probably know more.
- maxxxxx 8y agoWhy do journalists always change units? Usually they report a sale by valuation but with price per share I first have to look up the company and find the number of outstanding shares.
- alanwong 8y agoIt's journalists' job to highlight what's noteworthy, and in an acquisition it's not always the valuation of a company. In this case, the price per share is headlined to highlight the premium (55%) Tesla is paying for Maxwell Tech's shares.
- sitkack 8y agoI hope this doesn't affect the supply of Maxwell supercaps in the overall market. It really is star trek level technology.
- nisten 8y agoOk we know that ultra-capacitors carry about 10x less energy/kg than current li-ion batteries. This means they have limited use in small consumer cars, other than maybe helping the brakes or conditioning power. What they lack in weight, they make up in charge/discharge times. Being that a truck weighs multiple times more than a sedan, it's batteries are unlikely to absorb regen braking. So a small capacitor bank makes sense. A large capacitor bank would be useful if the truck was using overhead charging cables for a small section of the road. Or if a public transport bus was quickly charging between every few stations, it could then function all day. The large weight of the capacitor bank isn't a problem if it's used in a charging station, where 3-phase 400+ volt power may not be available. This means that any level 1,2 charger can be upgraded to a level 3 without needing to dig any trenches, further improving the user experience of the car owner and reducing range anxiety to a minimum.
- kumarvvr 8y agoCan these capacitors be used in any way for faster charging of the car? Like have a capacitor bank pre-charged and then unload it into a car for much faster charging.