Tesla's "Secret" Battery

They do have plug-in hybrids and I think those are the real solution to pure electric for now or until we find a way to make portable fusion generators. A small, efficient diesel or gas engine or flex fuel like E85 or E100, LPG etc. with a electric motor. As Lexel said, there’s no way we can ever get away from fossil fuels without innovation in alternative energy.

There are some localities that seem like they dont want you to own a car. They either tax you to death on it with registration fees, inspections, or charge high insurance. Since the feds took away the tax credit for buying an EV, there’s not much incentive to owning one other than…quiet, no engine maintenance (oil changes, coolant, filters, etc), cheap to refill (about $6 for a full charge at night), instant startup, and feeling good you’re (somewhat) reducing your carbon footprint. Downsides? Slow charging (unless you install a 240 or 408 volt service in your house), about 1/2 to 1/3 the range of a gas/diesel car, more expensive to buy (upwards of $10,000 to $15,000 or more), use the heater amd ac sparingly, expensive battery packs when they wear out. Regen brakes and software updates along with better batteries helps, but EVs are still a ways off from beating dinosaur burners.

I agree with this. An example is the Chevy Volt, which they discontinued.

Like you say the battery pack could be much smaller (so much less resources needed per car) than a pure EV’s while still using purely electric to power ~90% of our trips. Gas would only be used for longer trips. This seems like it would go a long way towards reducing gas consumption and would be a lot cheaper in terms of battery costs than pure EVs.

I know about traditional plug-in hybrids and agree they are the best option currently on the market for the mainstream consumer. The part that I don’t understand is why auto-manufactures still use a complex and difficult-to-design hybrid drive-train. The only thing that should be driving the wheels is electric motors. When the IC starts up, it’s simply turning a generator that’s directly charging the pack and/or powering the motor>>wheels. Total thermal efficiency for the steady-state genset could be as high as 45. Comparing that to ~25 efficiency of a typical variable load IC engine/transmission powering the wheels mechanically is enough to garner attention. But to think of the packaging freedom that could result from not having a mechanical driveline really takes it to another level…

I just think of how clean a steady-state, lean-mixture, SPCCI/HCCI petrol engine could run. Then to consider alt fuels like ethanol or LPG and I can only imagine figures flirting with 100g CO2 / mile

Musk thrives on exaggeration and unachievable expectations. His fanfare over the Mars Colonial Transporter was followed up by quietly downscaling and significantly revising the design, in contradiction with the way he implied the design was nearly complete. Several years later, they’ve now reached the developmental prototype stage, where they’re batting 1 for 4 at even passing ground tests. Hyperloop, meanwhile, is now looking like it might be better compared to the space ladder or the Moller Skycar.

But Musk does also usually have substance behind the hyperbole. SpaceX did ultimately develop a disruptively low cost rocket, and improved it significantly beyond the original design specifications, while also making it resuable. Tesla has the leading electric car on the market, bordering on profitable sales volumes despite the fact that their production cost appears to be significantly higher than originally planned.

I’m sure there is something to this battery announcement, too. Reading between the lines, I get the sense it is more related to cycle life and production cost than capacity. Regardless, there’s a lot of money flowing into battery R&D over the last few years, so we should expect at least gradual improvements.

There are 168,000 gas stations in the USA, with about 10 pumps per station, so you have 1,680,000 refueling points, so what you are saying is that ev’s will need 12 times the amount of refueling points, even though most charging will be done at home/work ?

As far as the grid is concerned have you any idea how much electric power is consumed by refineries, how much oil is consumed just getting that gas to you (boats/trucks etc) all that will stop :sunglasses:

As far as people not wanting things “in their back yard” that is always the case, try to build a new coal fired power plant or a nuclear one, no one wants those any where near them, but they will happily use the power generated in someone else’s back yard.

Please look around the net and get the facts before posting :student:

Cheers David

All around the US, electric grids are already strained. A heat wave brings about exploding transformers as ACs increase peak usage well beyond their rather conservative ratings.

I can imagine a spike in EV usage and charging bringing the grid to its knees.

Oh, and I just love the idea of using EVs as local batteries to supplement the grid. Put that many more cycles on the EVs’ batteries… No thanks.

We get this question all the time, nearly every week somebody (usually not an EV driver) comes up with this “range extender” idea on the EV forums. The problem is that you can’t charge a battery while it is being used to drive the car—the duty cycle of driving an EV with both motoring and regen modes, results in varying voltage and currents in and out of the pack.

Imagine the complexity of a Charger that would be required to compensate in real time for these currents; as it is now no chargers exist that will sink current, they expect to provide either a constant current or a constant voltage for a lithium ion battery pack. (CC/CV)

The conversion losses would be huge: convert fuel to run an IC engine and turn a loaded generator, then to extract electrical power from generator, rectify the generator output (AC) to create a high voltage DC buss with PFC, chop this DC thru boost transformers and rectify to create the DC voltage and current to recharge the pack. Now add some non-existent protection control stage to account for the acceleration and deceleration of the driver’s foot.

That is why the hybrids have both electric and IC engines, it is an easier cat to skin.

Most commutes are 50 miles or less, the newer EVs have 100 miles or more of range. You don’t need a range extender for commuting, but for the several times a year when you need to make a long trip, then go rent a car. Keeps it all simple.

It’s true that power is lost through mechanical drivetrains. This is why electric motors are so efficient-direct drive, no transmission, clutch, torque converters or solenoids and valves to actuate. Also no drive shaft. Not to mention the power delivery of an electric motor (100% power available immediately). As far as a hybrid drive train, the best ones are a diesel electric configuration. For those to be most efficient, they need to be run at a constant speed.

I think understand your logic and it sounds right.
Could the car not have 2 separate packs though?
One to power the car now while it is in motion and another that is powered by the IC when range or excessive current demands are obvious (heat, AC, Mountains) so the reserve pack is always topped up, the packs would alternate usage as needed. Then you do not need fancy charging logic?
Still have the home charging deal, just talking about in motion charging usage with the dual pack.
Just a thought from a dummy.

The only EV with unlimited driving range is Tesla, due to (1) their network of fast supercharging stations and (2) the thermal control system of their packs. Nobody else even comes close. Look up their 0-60 times compared with exotic supercars.

The Prius Prime does Toyota’s complex, but also kind of simple Power Split Device transaxle. And the latest Prius engine is over 40% efficient.
I think one of the issues with the steady-state-genset methodology is on-demand power and charge/discharge efficiency. Yes the generator/motor is efficient either way, but charging energy into a battery pack and getting it back out has a bunch of loss. The next issue is hard driving - If the genset is designed only to run at optimal efficiency, you’re probably looking at something like 20 horsepower (a guess based on optimal Prius engine range). If your driver is on the freeway driving a bit aggressive, or doing other not-recommended activities like towing (you should see what has been towed by a Prius…), that could be continually exceeded until the pack was depleted. With Prius Prime, when in Hybrid mode, the engine responds to demand and then takes a % off the top for charging - generally, depending on battery state of charge and current power demand level. If the pack’s low enough it won’t add any electric boost, it will only take take take… a bit higher and it will allow net 0 charging for the highest power demands, but still not give any charge up… and higher yet it will allow some electric boost to the drivetrain.

There’s been some other very interesting points about the viability of home charging for EVs/plug-in hybrids. Super valid! Not everywhere is suburbs. Yes, this model works very well for traditional American suburban living, but fails most elsewhere. Rural electricity grids may not be up to handling a fast charger at every location - and the same goes for stressed, dense urban grids. Even more for urban locations, is Space and Charger Access (as has been mentioned already in this thread). Almost everyone in a condo or apartment will not have charger access. The last time I went to some EV company’s website (I’m not even sure if it was Tesla or another), they had a survey that included questions about if you owned your home and if you had a garage (and detached/attached) to try to determine if EVs were “right” for you, in addition to other questions about daily miles driven.

A last point: I see a lot of arguments online about cost of ownership and cost of entry for EVs, but I rarely actually see “home charger installation” mentioned. If I fully drain the range on my hypothetical Tesla, how do I charge that overnight if I don’t have some kind of fast charger installed? A standard outlet/circuit in US residential is 120VAC*/15A, so 1800W. Wouldn’t the “base” of ~65kWh for a model S take 36 hours to charge that way? Okay, so you install a second Dryer outlet… pay the electrician… you get 240/30. That’s still a nine hour charge, and I’m assuming there’s no charging losses here. Or let’s say the 54kWh pack, current lowest for a model 3 (at least that I saw on Wikipedia). Still 30 hours for 120/15 and a work-night possible 7.5 for 240/30.

I don’t have time to fully respond at the moment but a few half baked thoughts here. First off, I don’t think I agree with the “you can’t charge while pulling a variable load from a battery” statement. I’ve worked in battery research and development for many years now and definitely have different experience. Next, I get a sense that there are Tesla fans among us. While it’s fine, the bias in this discussion won’t get us far. In terms of the complexity to convert an AC generator to DC… I say why are we not using a DC generator in the first place? I think an AC generator example creates a more complicated than necessary image of the system. I don’t agree either that renting a car every weekend is the most cost effective, practical, nor simple solution to having car that meets all of our needs.

Regarding the Prius system and IC efficiency, realize that the 40% thermal efficiency is a peak value under ideal load/rpm. To the wheels and in a real world driving cycle, low 30s is a more accurate figure. Toyota’s hybrid integration is definitely top notch and I respect it highly.

As for people misusing and overtaxing their car and potentially becoming depleted of pack power, I ask what would happen in a pure EV in that scenario? Also, if you were forced to pull over after such an event and allow the on-board system to recharge for a while, how is this different/worse than running out of gas or needing to plug-in?

Range extended HEVs aren’t the answer for everything, but I do believe they’d dominate a market share if effort was put in to creating one that functioned well.

PS: When bringing up charge/discharge round trip efficiency as a draw-back of a RE-EV, is this not also happening in every other EV/Hybrid that uses batteries?

Also, a split-pack design would be one way to get around any variable load situation. Also can be a way to do thermal management. Dual chemistry opportunities could also come into play here…

Sorry folks,
I’ll see myself out :beer:

Old-timey cars used to use generators, in fact. Simply a motor run backwards. The problem is that generated (haha) voltage was a function of rpm. Run the engine too slowly for too long, and the battery would discharge. Run it too fast for too long, and the battery would overcharge.

Also, the brushes would have to handle the full current being supplied. Sparking, electrically noisy, wearing very quickly, lots of drawbacks.

In contrast, alternators have the stators handling the bulk current. The rotor, connected via slip-rings, would handle much less current, and would be used to control the output (separate or integrated regulator).

So even at low rpm, you could overtickle the rotor so that maximum current/voltage could be supplied (within reason). And at high rpm, instead of frying the battery, you would scale back the tickle-current and still maintain a constant voltage.

“Converting AC to DC” was as simple as a diode-pack. 3 phases would have lot of overlap to appear as almost-DC (lots of ripple, though).

Last advantage is that the heavy-current windings of an alternator were on the outside, and could be press-fit to the case for good heat-transfer, and even have open vents to help cool the windings. A generator would have the windings buried inside, far from any good heat-path.

Nope, I’ll stick with alternators any day.

Don’t leave us hangin bro, you can’t throw out juicy tidbits like that and not follow up with some basic non-proprietary details.

I once conversed with a couple who had a Tesla and were towing a small, molded-fiberglass travel trailer. Besides planning their route to hit charging stations, they were staying in campgrounds with 50A service and using that to recharge overnight.

Exactly. And also cities will be so much quieter and with far less air pollution. But we also need a battery technology that is not toxic and limited.

Plus, there needs to be a way to cleanly recycle degraded cells.

Selling them to flashlight nuts on ebay is not a viable solution.

:+1:

There’s money to be made in recycling lithium batteries if done right, you know. It’s not really environmentally friendly and pretty expensive at the moment.