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henkmol

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  • Why Batteries Are Too Valuable To Waste On Solar Power Integration And Electric Cars [View article]
    John, MRTTF, thanks - there is such a tsunami of comment on this topic that you easily miss the technically relevant data. I'll read the discourse between you and tech01x. Regards Henk
    Mar 21, 2013. 04:11 AM | Likes Like |Link to Comment
  • Why Batteries Are Too Valuable To Waste On Solar Power Integration And Electric Cars [View article]
    MRTTF, Panasonic is actually quite reasonable about this.
    http://bit.ly/H4FaIm
    75% capacity after 500 cycles, see slide 34. It then depends on how you define capacity and power rating after 5k cycles. How you make redundancy in series-parallel packs of 18650 cells to level out the probability of total system failure, that is the science of probabilistic design applied to industrial equipment. BTW your acronym suggests know-how and experience on this matter :-( why are most people not revealing their true identity anyway?? )
    Best regards, Henk Mol
    Mar 19, 2013. 04:47 PM | Likes Like |Link to Comment
  • Why Batteries Are Too Valuable To Waste On Solar Power Integration And Electric Cars [View article]
    Hi John
    Reading into the information of Panasonic the capacity is now in the order of 10-12 Wh per 18650 cell (nickel aluminium cobalt / carbon technology with a typical capacity rating of 75% at 500 cycles. This is quite far from the 5k cycles.
    http://bit.ly/H4FaIm
    Regards Henk Mol
    Mar 19, 2013. 04:38 PM | Likes Like |Link to Comment
  • New Research Dissects Lithium-Ion Battery Mythology [View article]
    Hi John and other commenters,
    Just a note on $ / kWh and the kWh/kg. To my opinion everybody is juggling gross and net numbers through each other ending up this way or that on battery cost. Just have a look at the Tesla Roadster battery. It is made up of ~6800 standard 18650 size cells originally boasting 2400 mAh capacity per cell. They can be sourced from Panasonic who have proven cells with a capacity of 2700 mAh @ 3.60 Volt level average (check their 1 C discharge curves at room temp). Then, use 10% more cells to be sure to have the capacity at lower temperatures and at higher discharge rates. You could then get away with 5880 cells (instead of 6800) to make 53 kWh gross capacity. To avoid life issues, it is not uncommon to limit the range of the battery to 80% of its gross capacity for charge/discharge. Left is now 42 kWh NET capacity. It is then costing say 30 k$ (btw what is the actual $ price?) which amounts to 714 $/kWh. BTW the net capacity of the 410 kg battery thus made (assuming a 144 kg casing, cabling, cooling, reinforced walls etc and 266 kg of cells) the net capacity is 103 Wh/kg. So, on the cell level we have a gross capacity of 220 Wh/kg but after constructing a battery with long life we are left with less than half the net Wh/kg! Note that LiFePO4 cells would not be very good as they already on the cell level have less capacity. They future may hold surprises still. The technical possibility of LiVPO4 chemistry, using vanadium instead of iron, to boost the net capacity back to over 100 Wh/kg for the total battery system while avoiding the safety (thermal runaway risks) of LiCoMn chemistries is luring. Looks like vanadium could be an interesting metal to invest in after all, not only for Vanadium Redox batteries but also for Li Ion batteries.
    Regards Henk
    Apr 6, 2012. 06:47 AM | Likes Like |Link to Comment
  • Envia Systems – When Hype Becomes Deception [View instapost]
    BTW John, checking on their internet site they now show the original picture from Lux. Regards Henk
    Mar 9, 2012. 06:52 AM | 2 Likes Like |Link to Comment
  • Envia Systems – When Hype Becomes Deception [View instapost]
    Hi John Thanks for quick reacion. So wait and see. But what is the role of the japanse investors in this company then. Are they just parking pension fees or are they part of their knowledge chain? i.e. are they supplying input like patents etc on silicon nano tube production and application?
    Regards Henk
    Mar 9, 2012. 06:16 AM | 2 Likes Like |Link to Comment
  • Envia Systems – When Hype Becomes Deception [View instapost]
    Hi John, I sent a small mail today but then I saw that you already treat the Envia story. So here's a modified version of my mail.
    In the engineering newsletters there is quite some upbeat on the claims from Envia and nobody is criticising them in these media. This made me very very wary. And it is sad that they are doing doubtful claims as you show from your evidence. What is their motivation to do so, after all investors are not uninformed neither are they stupid. So, are they trying to keep their financiers of today happy? What do they really own? Are they running on Argonne's patents, a 4M$ grant FY 2010, and investors including Asahi Glass and GM and a couple of venture capital companies?
    They claim they can reach 400 Wh/kg of gross capacity in a lithium ion battery, doubling the classical Lithium-cobalt-oxide / carbon system's peak capacity of about 200 Wh/kg. When you look through the slits of your eyes you would be tempted to believe that a battery cost which would be halved with big consequences for the battery cost in a plugin hybrid car or EV. GM is not reaching its targets with their Volt sales at all because of the cost of the battery compared to the performance offered. On our way to Utopia, the doubling the capacity of a battery without doubling the size weight and price for the consumer would greatly lighten our burden.
    When calculating the capacity of a battery you have two entities: mass normalised charge capacity expressed in mAh/g, and electrochemical potential in Volt. to multiply the electrochemical discharge voltage (V) with the discharge current capacity (mAh/g) to get the power density (mWh/g) which equates to the Wh/kg. The total battery current capacity Ct equates to Ct = 1/(1/Ca + 1/Cc + 1/Qm) where Ca is the current capacity of anode in mAh/g, Cc is that of the cathode and Qm is capacity due to the rest of the construction i.e. electrolyte, separator, current collectors, casing, and reserve active material in the battery. Typical cells for laptops and handheld gadgets are based on carbon anode / LiCoO2 cathode on aluminium and a lithium ionic fluid electrolyte, and they have capacities of 370, 135 and 130 respectively which leads to a net Ct of about 55 mAh/g. Using a electrochemical potential of 3.7 V we have ~205 Wh/kg on the cell level.
    A packaged battery with many cells, thermal control system, and charge/discharce cell balancing electronics adds weight and reduces the net capacity which then reaches then about 120 - 160 Wh/kg in laptops and smartphones and more to the area of 80 - 100 Wh/kg in the automobile systems.
    I have been reading into the silicon anode technology which is the key of the Envia story, and for as far I can understand is that they have indeed reached something which is predicted in scientific literature. Clearly, they demonstrated successfully a combination of a battery anode with silicon/carbon nano tubes in combination with a cathode in the form of "pouch" packed batteries. But, when charging a battery the lithium moves from cathode to the anode and the silicon transforms into a silicon-lithium alloy. The swell of this alloy is a staggering 4x when fully reaching its potential of Li22Si5 (allowing world record anode material though). The reacheable capacity of alloying is much less, i.e. about 1/4 of that of the ultimate value but still causing high level of swelling i.e. about 60%. The stress causes the silicon alloy to fracture and the battery loses a lot of capacity (30 - 70%) already in the first few charging cycles. From literature I understand that the swelling may be absorbed by creating silicon/carbon material where the silicon is structured in nano sized hollow tubes, and swelling seems to take place such the the material is mainly expanding inside the tubes, reducing the interior volume, without significantly expanding at the outside diameter. The tube length change which also adds to the structural stress is not clear to me yet. So, if this is their tech trick then it can we worth looking at.
    At least they seem to survive a few hundred cycles (i.e. less than 5% of the required cycling) but it starts to become technically interesting. However real batteries have more requirements. They are, I quote from a good review article of Kasavajjula et al, "constant volume devices that are constrained by non-yielding outer containers and the inside is essentially non-compressible", and swelling is therefore a big issue. So when Envia shows pouch cells it is by definition not a battery. It is a technology demonstrator for the anode/cathode combination and many years away from a product in your car, or more practically your lawn mower.
    My conclusion is that we shall follow the progress of science on the material side in particular. If the material science yields mechanically stable battery materials that allow charging, i.e. alloying, silicon with lithium without pulverising it under its own stress when doing so then we have a first step. Then looking at the technology for producing nano carbon tubes it may indeed be well possible to produce by tweaked processes from ordinary chemical industries the silicon nano tubes (why else is Asahi Glass interested?). If these conditions are met then we have the first step in the diversification of our transport fuel systems moving from the initial stage of the hype cycle into a "slope of enlightenment" as Gartner tells us.

    Regards Henk Mol

    References used: "Nano and bulk silicon based insurtion anodes for lithium ion secondary cells", U Kasavajjula et al, Journal of Power Sources 163 (2007) pp 1003-1039;
    "Silicon nanowire anode for lithium-ion batteries: fabrication, characterization and solid electrolyte interphase", Wanli Xu, PhD dissertation, Louisiana State University and Agriculture and Mechanical College, August 2011.
    Various presentations published by the Argonne lab.
    Mar 9, 2012. 03:38 AM | 3 Likes Like |Link to Comment
  • Another Reality Check For EV Investors [View article]
    John, Glenn
    HEVs and even PHEVs make economic sense depending on where the energy comes from. For a consumer, it is not clear at all what it means - and this leads to lack of confidence in statements. Car makers are not clear about that either: this week, Renault made a press release where they state 57 g/km CO2 for EVs they are introducing in 2012 - which is absurd except when you make your electricity with nuclear reactors like in France. I think they should state this boundary condition! Now they omit it and consumers will be easily confused. Omitting vital facts about how you come to this value is a serious matter, for it ultimately leads to deep distrust or even hatred against, instead of enthusiam for, new technology. The Germans for instance have decided to stop nuclear fission in the long term - it is mysterious what will replace this gap. Are they secretly relying on shale gas to replace it? So, where coal and gas is burned to make electricity the pure EV is not making any serious dent in the total use of energy. It will make a difference when you look at the local pollution in dense cities. Gas prices may indeed go to $7/gal in the US and don't forget, in EU the gas price is about 1.50 euro/liter ~ $7.66/gallon. And we are happily driving 7.2 million cars in NL with 16.5 m inhabitants, averaging 14000 km per year per car by going on holidays, going to our work, the sports club, visiting friends and relatives, take the children to school, etc etc!! But the newer and smaller cars with e.g. start-stop technology and efficient diesels in particular are relatively popular nowadays, using tax benefits that make the price of a new start-stop enabled car at par with a 2-3 year old second hand copy of this car without start-stop or hybrid drive train. Problems will come when total spending on transport fuels are starting to interfere with the family budget and style of living. It is unlikely that families will then pay even more (premium prices) for pure EVs to mitigate their life style/income/spending discrepancies, they first will cut down on use of the cars, and perhaps invest in HEV as it comes with something earning itself back in a few years.
    Regards Henk
    Oct 21, 2011. 03:16 AM | 2 Likes Like |Link to Comment
  • Another Reality Check For EV Investors [View article]
    Hi John
    I take your point of 8.4 kg metals/person per year. It is all about sharing and division wealth - part of the world has all of it and part has practically none. I can't change that I think. I own two cars, total weight about 3 tons of metals and plastics, with a family of 4. Both cars are used at least 7 years before re-selling or scrapping. That is then roughly 110 kg of metals per year which is an order of magnitude more than the 8.4 kg indeed.
    Regards Henk
    Oct 21, 2011. 02:07 AM | 1 Like Like |Link to Comment
  • Another Reality Check For EV Investors [View article]
    Hello John
    Fact is, diesels are already more efficient and a compact car has no problem to make 4 liter per 100 km if you avoid moving nervously with the foot. I.e., a good diesel nowadays can yield 120 g CO2/km. Diesels have other problems like fine soot (particulate) emission which is hard to combat without reducing the efficiency. A further development of the combustion engine like the technology shown by Ricardo will allow petrol instead of diesel fuel with similar liter/km performance while avoiding the problems of the emissions of diesels. Hybridisation will allow further efficiency boosting in the 10% or more as this recovers at least part of the energy from decelleration, while it provides peak power at acceleration without the need for much larger engineering dimensioning of the gear train and combustion engine. This trimming down reduces the total friction losses. I agree with John that this has consequences for the batteries indeed.
    Those battery makers that will survive will be the ones that 1. can make good batteries (life and performance) 2. for a good price (so not at 900 $/kWh but at least 5 times less than that), 3. high volumes (>1 M per year) with 4. a recyclable chemistry (until now only lead acid batteries, and a part of the NiMH batteries, are economically recycled). Lithium batteries until now are NOT recycled as it costs more to take them apart than replacing then with new. This is bad news for the EV fans indeed. But my worries extend to someting else on the horizon as well.
    Despite decline of oil consumption in OECD the total production of crude oil flatlines already for 6 years on 73 MBarrel/day. Including condensate, we are at about 84-85 Mbbl/day and holding steady. Until now. So, the decline in OECD demand is at present entirely absorbed by the non-OECD growth, in particular Brazil, China and India seem to be consuming more oil. What does this have to do with efficient cars?
    Half of the 85 Mbbl/day goes into refineries for diesels and petrol, i.e. cars and truck fuels. So, traditionally the effect is that if you make your entire fleet 2% more efficient by modernising the combustion engines the total effect is a 1% reduction of total crude/condensate oil consumption. Until a few years ago, this one percent had an enourmous effect on the price of oil. I saw in a study that a 1% shortage on the crude market escalated the price 3 to 5 times its equilibrium value. Reversely, when the major consuming countries in the period around 1983 were contracting the oil consumption went down with 13% which plummeted oil prices down to $10/bbl. The world seems to now deviate from this historic relationship due to the likely peaking of the total liquid fuel supply.
    From the North Sea fields it is known how the plateau of production works out: at the end of the plateau, the well output abrubtly goes into a fast turn-down, cutting the production at 4 - 6 % annually. So, when the super giant field Ghawar is starting to stall, while the non-OECD is in fast forward mode with its growth of consumption of fuels, the result can only be that oil price will shock back into such a high level that we in EU (or US for that matter) will start to feel the bite. By the time this price shock sets in, will the consumers have the financial strength to replace their cars with efficient ones? This worries me indeed, the fact that by the time this new fuel shock arrives in full force there is a delay in awareness for months or even years, and by the time the political will is supported by the public to move to high efficient cars including plug-in hybrids, the public may not be able to afford these new technology cars anymore. We always assume that consumers have a choice, but nowadays I encounter quite a lot of folks in my middle class environment that face losses in their savings, failing investments for pensions, and difficulties to pay back their mortgages. In other words, by the time the new technology is available but at premium price, quite a lot of the consumers that used to be interested may have simply run out of financial reserves due to increasing cost of living and a stalled income growth. So, will the consumption of new technology also be dominated by non-OECD areas in the world? Some questions from my side. 1. Does any reader or commenter have an idea of the delay times involved in this consumption scheme. 2. is there some quantitative reasoning how the scenario's may be unfolding for HEV and PHEVs.
    Regards
    Henk Mol.
    Oct 20, 2011. 04:12 PM | 1 Like Like |Link to Comment
  • Micro-Hybrids: The Fuel Efficiency Innovation Of The Decade [View article]
    Hi John I sent a few mails to your address for further discussion. I also stumbled into a few good presentations now published within the site of the LCV2011 conference of september 7-8 lately, see http://bit.ly/pq6DoW where also Axion talks about Li ion, and Control Power Technologies shows electrified parts that were originally belt driven. I also found that induction motors do not necessarily be much larger than high end PM motors, earlier I found ca factor of 3. AVL Powertrain ltd showed that the difference in advanced induction motors is 30% larger mass and size, similar torque, but generally lower (87-88%) efficiency than PM BLDC optimised (91-92%) at the operating work point of test rotation speed and torque. So, some of the bickering of PM costs is more about what compromises you have to make given size/mass restrictions. At very low speeds the PMBLDC and AC induction motors start to show larger size differences than at medium speeds of say 2500 - 3000 RPM. VR motors (no copper nor magnets in the rotor just steel) are also feasible, they are in the efficiency range of 89-90% but their size is clearly bigger although the total mass is not (copper is left out of the rotor, some air spaces are left over). Regards, Henk Mol
    Oct 7, 2011. 09:19 AM | 1 Like Like |Link to Comment
  • Micro-Hybrids: The Fuel Efficiency Innovation Of The Decade [View article]
    Hi John
    I think we agree indeed - I learned thus that without the right price level nothing in consumer and mass manufacturing will ever go and that was the bottom line when we discussed EVs and long distance large battery PHEVs in your previous articles and concluded that the technology is not viable for us - regardless of what wishes we have the Lithium battery is just outrageously out of bounds with respect to revenue vs cost for both the battery maker, and the consumer. The short-distance PHEV like the upgraded Prius 2012 does serve the 50% of trips that proved to be less than 10 km in average city environments. This can be handled by consumers as they may than have a car (a real one no compromise) and live in the city where local regulation will make owning and operating anything that is not electrical might be expensive. So, local air pollution and noise requirements may create then this PHEV market. Same for Start-Stop: cars moving by are less irritating than cars idling in front of their doors unnecessarily if you ask individuals in the city. Start stop kills the engine when standing still. So, the combination is unique: there is a need at the customer level + it is now technically possible + it is possible at limited individual cost + development teams are in place to bridge the gap between the R and the D. This is the product-market combination that makes sense locally and globally. We'll be in touch. Regards Henk Mol.
    Oct 7, 2011. 06:25 AM | 2 Likes Like |Link to Comment
  • Micro-Hybrids: The Fuel Efficiency Innovation Of The Decade [View article]
    Hi John and other commenters,
    Thanks helping in collecting a perspective in this field.- truthfinding and factual agreement is what is lacking today in most comment sections also in engineering blogs. The people that actually design and produce the system and know critical details do not give out any information scared as they are that competition will use the ideas. Working with this matter myself and visiting several scientific conferences has taught me something as well and the 15% fuel saving by start-stop only is overestimating with factors the net savings. But, you save this mainly by cleverly reducing friction in many many separate little things, and by replacing continuously running parts with on-demand running parts. E.g. the hydraulic units like the water pump and the power steering and brake pressure compressor can be taken off your belts, and when you run them with electric motors on demand the net energy lost in these hydraulics is saved. For one thing it can remove or at least reduce the oil cooler. The electricfication however puts tremendous extra power loads on the electrical system so your battery system has to migrate to a much more robust one too. Most Pb batteries will absolutely not fit the job now asked for - not only due to start/stop but due to the movement into less belt driven subsystems. I am quite sure that start/stop only does not save 15% fuel you have to do a lot lot more like total loss reduction and recuperation of the decelleration energy. Regards Henk Mol
    Oct 7, 2011. 04:42 AM | 1 Like Like |Link to Comment
  • Micro-Hybrids: The Fuel Efficiency Innovation Of The Decade [View article]
    Hi John, Marvelous information indeed. Thanks a lot - for me it clears the missing links I had in the start stop story. The battery problems are the real crux in the story, this is for me the icing on the cake. I am puzzled though on the claimed fuel savings. I recall that start-stop saving is in the order of 3% in fuel based on testing by Ford on delivery vans and cars in UK. And to earn itself back for a 4 year period the complete start stop belt driven unit has a cost limit of about 120 euro over the original alternator. The belt driven system is able to produce nearly 4 kW of power in a 0.5 - 1 second time range, using a step up converter delivering from 12 V the 40-60 V at most but not higher as this may lead to failures in the electrical insulation and connectors. As alternator it is roughly 1 kW @ 14 V DC converted. To get the max 15% saving you also need deceleration energy recuperation - i.e. a mild hybrid or full hybrid of some sort. Belt driven start-stop systems do not use this feature (yet) at the scale that we need but some work is under way. The brake action needs fairly large powers beyond 5 kW to actually be effective. To act as a 5 or 10 kW generator for 3 - 10 seconds is beyond the thermal limits of the typical 15 cm or so size of the current startstop electrical engine. The insulation quality degrades exponentially with temp and every 10 deg C halves your insulator's life, so very hot temps are avoided in the alternator. Yet incidentally there may be rotor temps of 150 deg C, not very nice to the rest of the stuff to be honest. IN my opinion, the way it works now is already a challenge and further cranking up the power levels does not look realistic.
    Regards Henk Mol
    Oct 6, 2011. 02:52 PM | 1 Like Like |Link to Comment
  • Energy Storage: A Bloody Q3 Creates Great Buying Opportunity [View article]
    Hi John - OK so we may be barking up the wrong tree...
    Tnx! I'll have a look at the material. My employer produces also parts for StartStop systems so I feel responsible to folluw up.
    Regards Henk Mol
    Oct 4, 2011. 04:20 AM | 2 Likes Like |Link to Comment
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