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Battery tech

Hello all.

Just read from autobloggreen about some new battery manufacturer called "Planar Energy". (http://green.autoblog.com/2010/07/27/planar-energy-to-begin-small-scale-...)

They seem to have tech for pretty good Wh/kg batteries. From one of their pdf (http://www.planarenergy.com/Press%20Releases/Technology%20Review_%20Safe...)

"One of them combines lithium manganese oxide with other ions, and operates at about three to five volts with a charge capacity of 200 milliamp hours per gram."

Calculating that as 3.5V * 200mAh/g you get 700mWh/g or 700Wh/kg. to put that in right context: Roadster battery: 450kg. Drop 30% off as supporting structure: 315kg battery * 700 = 220.500kWh battery. Nearly four times as much as current tech is. That would allow roadster to go 200 * 4 = 800 miles with one charge.

@DanAderhold; electric motors already have 95%+ efficiency, which is one of the highest energy transformation efficiencies humankind have managed to make. It can be made even better, but you wouldn't get much improvement no matter what you do because you can't get over 100% efficiency. So keeping the cost (and complexity) down is priority there.

Now if someone could invent an electric motor that doesn't lose torque with RPM increase _that_ would be real invention. You would get the real "Horsepower" out of the engine (IE. max torque at any RPM would stop you from accelerating only when car losses exceeds torque output and you would get the HP at max torque).

I don't see any physical reason why such engine cannot be made. Horsepower is not real power because RPM is not a force just angular speed measurement, it doesn't really tell you anything, not even top speed because that depends of the car losses. Torque is a real power, and that determines the force that accelerates the car.

Timo,
I would disagree, your assumption is generators are the same, and require electrical power to drive at all times, and is wrong, only require forward motion. The generator would not turn “ON” and “OFF”, and would always rotate when vehicle is in motion. With correct generator configuration, magnetic shear would be quite minimal. You maybe assuming there would be frictional lose and that isn’t true either. There are configurations that have “NO” frictional components. Your suggesting there’s no way of regenerating power while vehicles in motion, that’s simply not true. Smaller battery units can be charged using vehicle forward motion, with generator and solar cells.

Load is depleted faster through higher current demand, you know this. It is not proportional.

Dan;
You're saying you want free energy, whether you know it or not. There Ain't No Such Thing As A Free Lunch. (TANSTAAFL) Or free erg.

Magnetic or no magnetic, if you extract energy from kinetic energy (movement) you slow down that movement at the equal amount of the power you drain from it + losses. There is no escape from that law of physics. Motor turned to generator is a brake. Even zero-weight, frictionless generator would be a brake. Even if there is no losses in that generator, only that brake-part, you have the main engine losses to deal with.

Adding an generator you add an brake to the system and you same time add all the losses that transformation includes. It is much better to use battery directly.

Tesla - No need to be concerned that am former GM Engineer, I have watched your company grow for some time. I am a big supporter, one that would assist you, whether paid or not.

Timo,
Yes torque is a problem with increased RPM. I have interest in ferrofluids, superconductive materials, and several motors technologies not to discuss here. I understand the concerns and especially cost per unit toward production. You probably gathered am a former GM Engineer, and worked with all Big-3 in MI.

I don’t like talking too much about technology in these forums. I understand the need to keep cost low, and make steady steps moving forward.

And Electric Cars were introduced over 100 years ago, about 25 mph and 100 miles per charge (1909 Baker Electric). They also had charging stations.

Let’s make sure the word gets out for all associated technologies.

http://vodpod.com/watch/967762-1909-baker-electric-car

Brian H,

I am not talking about Free Energy, that's a catch phrase. I’ve been around too long, try energy distribution with respect to loads. I know Tesla Advanced Technology is impressive, I admire this company more then you think. I have worked with engineering teams for many years, my job was to take, “What many believed wasn’t possible, and make it possible”. And well aware this is what Tesla accomplished. I worked in Asia for a number of years, vision systems using laser and HS camera technology. One task was to improve 95% detection to 100%, many believed this wasn’t possible, but it was systematically accomplished with advanced thinking and new theories.

I am not going to discuss technical detail in these sections. Free Energy, don’t make me laugh, nothing is free!

Timo,
There are other factors besides kinetic energy, and you’re aware. In terms of systems and so forth, this isn’t the appropriate format to discuss engineering concepts. I prefer to promote these technologies, and good CRM always helps.

Brian H,

Sorry I don’t believe in “Free Energy”,
Timo and I were discussing loading versus chemical decomposition. And of course am joking, good luck to all.

Regenerative power is created when motion or energy loses generated by the vehicle are converted into reusable power. As someone stated, “By extracting kinetic energy you slow down movement by the equal amount of power you drain” and true, but power and efficiency must be considered. In an idea application there are no loses, but in real applications there’s always loses. An example, a person pushes the accelerator and consumes power, and thereafter pushes the brake. The reason, too much kinetic energy was created, so driver slowed down the vehicle. This action resulted in power lose; because brake energy was used to absorb kinetic energy created by the motor. The indicator of this inefficiency was the intermediate braking used to reduce the kinetic energy and slow the vehicle. Regenerative power is realized when this response is sensed as a potential energy lose, and system applied to collect this energy and convert to power and store for use on demand. A vehicle applying regenerative sensing and energy collecting is complex, but feasible.

The ideal transportation system can start, accelerate, travel at constant speed, decelerate, and stop when traveling from location (A) to destination (B). However automobiles often continuously stop, start, accelerate, and decelerate at various locations from (A) to destination (B). In some cases a constant speed can be maintained from location (A) to destination (B), but in rare cases. So it’s important to increase vehicle efficiency when possible, because infrastructure isn’t that efficient. And it’s not uncommon to examine various possibilities of converting inefficient energy use to efficient use.

One method is accomplished by applying traction control technology, and improving efficiency by regulating the power used to achieve forward or reverse motion with minimal slippage. Other research is performed for other applications, to increase driving distance, and for extending the life span of batteries.

A power factor can be measured from the distance traveled (start to stop), because power isn’t constantly consumed to maintain forward motion. This power factor is related to the efficiency of energy consumption to achieve the motion, versus the energy consumed to reduce or counter the motion. One method of increasing the vehicles efficiency is to convert some forward motions (kinetic energy) into regenerative power, or some energy will be depleted through counter motion (braking energy loses). In some cases when vehicle is accelerating with minimal or no current load to motor, the acceleration component (kinetic energy) can be converted into electrical energy using a generator. Regenerative power is achieved by first detecting “potential energy loses” and then converting this energy into electrical. An example, the driver pushes the accelerator and thereafter releases and taps on brake, at this moment the generator coil is engaged to collect energy, and disengaged when accelerator is depressed again. When the driver releases the accelerator, and taps on brake, this indicates too much kinetic energy was created. And for those concerned with continuous magnetic braking, the coil is extended or retracted depending on controller and sensing of regenerative power potential. This application is feasible by using a permanent magnetic generator inside one or more wheels of the vehicle. With the purpose of charging a smaller battery source used to supply power to the standard systems located on the vehicle. Like lighting, both interior and exterior, radio, power seating, wipers, air, amongst other.

Regenerative power systems can be developed with intelligent algorithms, to sense potential energy sources, and engage, collect, and disengage. As stated above, by extending and retracting the coil, the program logic would measure the power applied versus forward motion, with ability to engage and disengage. A solar roof would also be used to charge smaller battery as well, so there are several sources for recharging. The solar cell is feasible when the power source (battery) is smaller. If the smaller battery had insufficient charge, the secondary systems can be electrically connected back to primary power source.

The affects of current loading on battery are, (1) Higher load currents create thermal energy that requires battery cooling. (2) As current increases, more energy is required to cool battery, and therefore more power. If the thermal energy is not converted into power, it’s an energy lose. (3) Higher load currents increase the rate of discharge and shorten drive time. (4) Higher load currents increase the rate of chemical decomposition, and thus shorten life span of battery.

Therefore adding a generator and small battery that’s configured correctly will add value to the system, in many ways. The added weight isn’t significant, less then 50 lbs at most, versus each passenger at about 150-175.

@Dan

1) generator placing in tires is a safety hazard, unless you counter its braking effect by braking other tires as well (car balance), therefore losing energy.

2) I very much doubt that adding extra battery with extra generator with associated electronics would be any more efficient than motor used as generator even when used only when vehicle is slowing down.

Also that cannot be used when traveling far, because in that case you are either doubling the losses for those ancillaries or you lose them. In those conditions car needs to use energy to sustain movement and you can't use generator without doubling the losses.

In any case even if you could get something out of this the difference would be so minimal that added weight, complexity and cost would probably be better used to just install a bit bigger battery instead.

@Timo,

1) Yes, the best solution is using two generators to balance vehicle, even though magnetic shear would be minimal. These generators should be in phase with drive motor, due to regenerative braking from drive motor.

2) As you know some motors can be used as generators, however most are not designed for this use. The reason for various motor and generator designs is due to application versus efficiency. A motor can have high efficiency rating when used as motor, but low efficiency when used as generator.

3) The efficiency of system is observed by use of power, and whether or not potential loses can be converted into energy for regenerative power. Regenerative power relates to generators in wheels, used when potential energy loses are detected, the use of thermal energy TE Technology, and alternative sources such as solar roof. So idea is to evaluate potential loses and ways and means of compensating to increase power efficiency.

Brian H and Timo,

Farewell, and good luck..

The microbial fuel cell part seems very similar to what I did back in college. There are alot of issues with microbial fuel cells.
Typically, you use something like yeast, methylene blue (electron stripper), and ferrous II cyanide separated by a naphion membrane. Biological fuel cells are a good idea, but in practice, getting them to work long term is rather difficult.

1. They are VERY sensitive to temperature (rule of thumb is for every 10 degree C, double the microbes biological rate)
2. If it's a photosynthetic bacteria, you need sunlight and water, if not, you need another fuel source (typically polysaccharides along with other materials)
3. I know when I was working on them about 8 years ago, the cell life expectancy was on the order of a 1 week or less, either the microbes ran out of food, the yeast clogged up the cell, the anode degraded, or the yeast died due to the fuel cell "stealing their energy"

It seems that currently the biggest drawback to EV is range/recharging. Sounds crazy but the addition of a gas generator onboard could extend the range considerably. A 27 lb generator,converted to Liquid Propane Gas (LPG) could produce 1,000 watts/120 volts for hours depending on the size of the LPG tank. The tank and generator could be placed underneath and in the middle of the vehicle for safety.I know this is not ideal, but until battery technology/life improves, this technology is here today. LPG is very low in carbon emissions, is more prevalent than E-85 or electric outlets. At 20 feet away, the generator emits 47-57 decibels, which could be greatly reduced with an exhaust system.

gmackin: A 1kW generator would be useless, just like charging from 120V is mostly useless unless you can leave the car to charge over a day or two. It takes about 15kW for highway cruising.

"It seems that currently the biggest drawback to EV is range/recharging."

Only to non-EVers. My EV charges while I sleep and I start every day with a 'full tank'. My present EV, 2000 model Th!nk City, has sufficient range - 60 miles - for a day's driving.

I remember Elon once talking about riding the wave of battery development. Here comes the next wave: A Li-Ni battery with a massive energy density, which would bump the range to 700 miles. Is this what you were referring to in your original post, Timo? It's Still in the development phase, so probably not out in time for the first S, but maybe by 2014 or so... Tesla, are you working on this new battery tech at all? Here's the article:

http://gas2.org/2009/10/06/new-nickel-lithium-battery-has-ultrahigh-ener...

If the fragile glass membrane is the issue, could it be reinforced with carbon, or a membrane like safety glass? Industrial ceramic?

Here's another interesting Technology - using nanoparticles to generate electricity from waste heat. Still very experimental.

http://www.physorg.com/news204552797.html

No, that's not the one.

http://pubs.acs.org/doi/full/10.1021/ja906529g full text has this:

"Then a practical energy density near 428 Wh/kg can be expected for this cell chemistry."

That battery I was referring to is was Planar Energy battery with more traditional chemistry.

What I referred was guessed Wh/kg from chemistry alone. Someone from Planar energy mentioned this in comment section of Technology Review -page:

quote:
"The design point for the prototype Planar cell, fully packaged, with a capacity of 5 Ah, is a specific energy of a little over 400 Wh/kg. The energy density of this cell is a little over 1200 Wh/l. Larger cells will yield numbers that are improved a bit. "

http://www.technologyreview.com/energy/25825/

So, not quite that good, but thing is that this is already in prototype-phase and that volumetric energy density is really good. 90+kWh battery would be only 75L in size. Small size helps to position it easily into BEV. Also it would weight (without supporting structures) only 225kg, which is about half of what Roadster battery weights now. Less weight = better performance + less rolling resistance = bigger range/kwh.

i am interested in the model s but my only concern is the problem that i am having with my golf cart. that is the batteries that run the cart die and i have to buy new ones which cost \$\$ so i was wondering how ofter or if at all would you have to replace your batteries and if so does waranty cover it?

When I remember right the expected lifetime of the battery pack is expected to be between 7 and 10 years. At that time you will note that will not be able to drive as far as you used to.

To buy a new battery pack right now it seems to be 30'000\$ and you have can buy a replace battery option and then it will cost 12'000\$

If battery technology will continue to develop like in the past few years, at the time you need a new battery it will be already better and cheaper... also if you have your car for around 8 years you will consider buying a new one anyway.

That's just what I read here, didn't heard anything about the warrenty yet.

SOLAR POWER. Wouldn't it be neat to add a solar panel somewhere on the body of a Tesla vehicle so that you can have continuous charging even away from an outlet? It would be a supplement to the outlet charging and would even allow your vehicle to go miles farther between outlet charging.

With a one square meter solar panel you might gain one to three miles if you get 10 hours of sunlight during a day. A good day. 1.5% or less increase in range. Probably less. Pretty much not worth the cost.

Here is what I want to know and really it is THE Question when it comes to BEV's, what is the current AER for Tesla and how does it compare with other BEV's? I see precious little details on that here or anywhere, lots of claims, but no detail. Help a brotha out.

The Rick,

By "AER" I assume you mean All-Electric Range? And by "Tesla" I assume you mean the Tesla Roadster?

It's published at 245 miles. It's not a claim. The car's been on the roads and has accumulated, I believe, over 6 million miles now. Thousands of people have logged anywhere in the 200s to over 300 miles in the car...hardly a claim. (Range of course varies dramatically by the hundreds of variables that come into play).

Go to www.teslamotorsclub.com if you want to directly ask Roadster drivers. That forum is crawling with them.

Other BEVs? Well, there's the Leaf at around 100 miles...and the iMiev at around 100 miles...and...

Well, currently, there's no comparison.

All other BEV manufacturers are making basically city cars with ranges varying in little over 100 to 75 miles. Tesla seem to be the only one that has realized _from the beginning_ that this is not enough. Not even with fast chargers in every corner. If you need to charge every 80 or so miles in long road trip it would become really annoying really fast.

Timo:

RE: 428 Wh/kg battery- Yeah, great density! So is Tesla working on this? When can we see these batteries in normal production and installed in a Model S?
(You seem to be a Tesla insider ...?)

I'm not Tesla insider. Just REALLY enthusiast "Tesla enthusiast". I have read these blogs pretty near from the beginning and I read all other sources I find that have any bits of information about Tesla. So, no I have no idea about what battery tech Tesla will be using in near future.

The immediate future is quite clear: http://is.gd/fNFfh
This is likely to push e.g. the roadster's range to a solid 500km. Beyond 5 years from now predictions are difficult to make. Martin Eberhard has stated that he expects ranges to reach 800 km within a decade: http://is.gd/fNFbA with similar technology, using essentially the current Tesla setup with just newer cells. What other cell types will be able to keep up is very uncertain. The mass-production advantage of 18650's is proving hard to match.

Alfred

http://web.me.com/alfredar/Alfreds_Pages/Electric_Cars.html