How do we make the Volt cheaper?

Two quick notes on things that happened this week. The first represents the present; the second (hopefully) the future.

Chevy Volt pricing:

Its $41,000. No surprise there. There is a tax rebate that gets this down to $33,500. The leasing option seems cheaper, but seems limited to 12,000 miles a year. I drive 18,000 a year and I rent (which means no charging at home for me). I will not be in line for one anytime soon.

The Nissan Leaf is $33,000 before rebates and $25,500 after. This seems so much more manageable, but its only a 100 miles range. You win some, you lose some. What we need is a cheaper battery.

Which leads me to�

A discussion of the future of the battery:

Those who follow this blog know that most of us at LBNL work as part of a large program called the Batteries For Advanced Transportation Technologies. The Program is funded by the US DOE and has researchers from all over North America. It�s the top battery people from Universities, National Labs, and companies. The team reads like the who�s who of the battery world. The goal of the Program is to perform the research needed to discover and make the next-generation batteries.

This week on Tuesday, all of us met for a day at LBNL to discuss the future of batteries. We discussed ways to make higher energy, lower-cost materials, methods to make the battery last longer, and the challenges with moving to new batteries that promise significantly higher energy density compared to today�s batteries. Below is a photograph that we took at lunch.

I will try to tag the picture at some point.

Venkat

If you build it, will they come?

Many of you have probably come across the piece by Andy Grove titled �How to Make an American Job Before It's Too Late� that was published in Bloomberg. In the article, the former president of Intel argues that losing low-end commodity jobs from the US is a long-term problem. He uses batteries as an example.

In the battery space, all manufacturing of lithium-ion batteries happens in China, Korea, and Japan. Since the mid 90�s when it was becoming clear that lithium-ion was going to be a dominant force in the rechargeable battery market, several US companies have tried to enter the market by setting up plants in the US. None made it big. Some went under; others went back to their core business; still others survived (and continue to do so) on small government projects.

An article written by Ralph Brodd examines this issue in detail. The article is a bit dated, but is interesting reading. Ralph concludes that there are many complicated factors that come into play. Some of these involve the difficulty in penetrating OEM markets (that were all in Japan) for US companies and the fact that lower profit margins were sustainable in East Asia. Interesting he also notes that labor costs are not as significant in this �outsourcing� trend as some claim. I suppose if you automate you can depend on robots not to ask for a minimal wage irrespective of the geography!

Long story short, by the turn of the century, the battery community had accepted the fact that there was no real Li-ion manufacturing in the US. However, most of the community also believed that innovation in batteries happens in the US, and manufacturing (read �low end jobs�) was dominated by Asia.

There are very good reasons to believe that. The materials that power your laptop and cell phone batteries were discovered in the US. Some of the materials that may end up powering your plug-in hybrids and your electric cars were discovered in the US. Ergo... the US leads in the �high value� innovation; Asia does all the �low end� manufacturing.

Andy Grove had come to LBNL last Fall and during a discussion on battery research, he asked what the rest of the world was doing. I answered (echoing the popular belief) to the effect that Asia (read China, but also Korea and Japan) leads manufacturing and the US leads innovation. He cautioned that this was exactly what the semiconductor folks thought, but in time, they started to realize that Asia was starting to do more than just low-end stuff. And he cautioned that the realization might come too late.

What he was talking about was already happening in batteries; it�s just that I was not paying attention. Japan was always a powerhouse in battery R&D (with the Korean�s not far behind), but the last few years are showing that the Chinese are doing just fine, thank you. The number of papers coming from China is increasing and there is a lot more research activity than even a decade ago.

In effect, it is possible to outsource not just �low-end� jobs, but even �high value� R&D. Certainly the last decade has shown that industries ranging from software to pharma are outsourcing their research to China and India.

One could argue that quantity does not imply quality, and impact of papers from the US tends to high compared to most of the world, especially the developing world. But I would argue that as each year goes by, you can expect to see the quality and the impact improve. With money comes equipment, personnel to hire, ability to travel to conferences, and the ability to collaborate with the best and the brightest the world over. And despite the recession, China has continued to grow. If you are looking for money, China is the place to be.

If the manufacturing is in Asia, the talent is in Asia, and the funding is in Asia one can logically assume that future breakthroughs will happen in Asia.

The question then becomes: How does the US get back on the driver seat?

The US DOE decided that one way to do that was to bootstrap the development of a battery industry in the US by providing stimulus money to build factories. A few different companies got funded as part of this effort. These companies will be ramping up manufacturing of vehicle batteries in the coming years and slowly but steadily, the US will ramp up battery manufacturing for next-gen cars. Over the last week, the government issued a report on the impact of all this funding and their expectation of battery performance and cost over the next 5 years. The report, predictably, paints a rather optimistic future.

However, there a couple of problems to worry about. For one, the batteries that are being made have to be sold (Sounds obvious, but I think its worth reminding ourselves of this). For this to happen, there has to be a market for plug-in and electric cars. And as we pointed out these cars will be expensive because of the battery cost. Mass manufacturing will decrease the cost, but for mass manufacturing you need someone to buy these batteries and so you have a chicken and egg problem. And even the decreased cost will still make these cars expensive.

Moreover, most (if not all) of these companies are essentially using the money to build a building, and buying equipment from China, Japan, and Korea to make batteries pretty much exactly as they have been made in Asia except that they are doing it on US soil. Even the chemistry for the anode, cathode, and electrolyte that are being used for are not really unique.

Its not clear is there will be any unique intellectual property that will come out of this. Maybe in time, IP will come, but in the short term there will be little that is different from the batteries made in Asia. These will be expensive batteries with no clear technology advantage over the Asian rivals, but made in the US of A.

But the funding will create jobs, reduce battery costs, allow us to start the process of innovation and IP generation, and provide a pathway for the wonderful research in the Universities and National Labs to reach the marketplace. In the long run, all this can only help.

But in the short run, it is not clear which markets these companies will sell their batteries to and how they will stay in business long enough for all these benefits to occur. I believe that a vibrant PHEV or EV marketplace is key, but it�s not clear how one should enable this. None of the solutions are easy (e.g., a gas tax). But does appear that without incentives, it will hard to jumpstart an electric economy. We may be forced to make these hard choices.

This would be the �If you build it, they will come� route.

Instead of going this route, one could try to do something radically different; generate IP; use this IP to manufacture in the US, and leapfrog Asia. Leapfrogging in batteries is not easy (I suppose by its very definition leapfrogging is not easy!) and as I have noted, Moore�s law is like Murphy�s law for battery folks (we cringe at the mention of both). But one can imagine a new material or a new way of assembling a battery coming along that makes the existing methods obsolete and makes the US the leader in manufacturing as well as research.

There are a few governmental programs that are aiming to do just that. And certainly the whole of Sand Hill Road (which would be the street in Menlo Park that houses many of the Venture Capital firms in the SF Bay Area) is looking to see if they can find the next big startup with the winning idea. Only time will tell if the numerous startups and projects that are attempting to do something radical will end up being truly disruptive. And as I mentioned in my post on David vs. Goliath (or Tesla vs. Toyota), succeeding in the battery space can be hard.

In the meantime, all of you can do your part to keep the battery economy moving. Pay the $40K or $100K (depending on your affordability) and buy a Chevy Volt or a Tesla Roadster. This may mean selling your home, but, as the last few years has taught us, home ownership is overrated anyway.

Venkat

Have Solar Panel. Need Batteries.

I'm on vacation in the east coast of the US for the week and the sun has been relentless. I can only hope to have clouds and maybe a shower or two to cool things down.

But mention clouds and the solar photovoltaic folks start to go berserk. Apparently solar panels have a hard time being of any use when there is no sun! An hour of clouds and your power generation tanks. Two days of rain can make dependance on renewable electricity seem like a return to the dark ages.

Enter batteries. Why not store the electricity during the times we generate it and use it in the night/when there are clouds etc? Sounds like a great idea, but the problem is... you guessed it... those batteries!

Anyway, long story short there are some batteries (different from vehicle batteries) that have the hope of being very useful for these sort of renewable storage applications. We are talking about MWh of storage (the M is for mega, so... big). There are a lot of batteries that are needed for this application, but the cost of these batteries is a problem and so is the lifetime. A third problem is that the energy efficiency of these batteries is not that great (maybe 50-70%). When someone tells you that the energy efficiency is 50% it means that you use twice the energy to charge the battery than you get on discharge. So 50% of your solar panels are a waste (great for the solar panel maker. Bad for the customer).

ARPA-E, the new kid on the DOE block, came up with a solicitation looking for ideas to fix these problems. This week, they announced a bunch of awards for some interesting new technologies that promise to solve these problems. One of the awards went to your faithfully (that would be me) along with two of my colleagues from LBNL- Vince Battaglia and Adam Weber. For the project we assembled a team consisting of Robert Bosch, DuPont, and 3M. We also had Proton Energy has a partner to help with some designs. Its an amazing team that beings together knowledge of electrochemistry, catalysts, membranes, and balance of plants to work on a battery called a "flow battery".

I will try to expand on what we proposed in the near future. If we (and any of the others funded) are successful, then we can get a step closer to having a more efficient grid. Click here for the list of awardees.

Till now, my blog has concentrated on vehicle batteries. I think its time I expanded into grid electricity. This is another big problem and something that needs attention.

In the meantime, for all your solar enthusiasts that complain about your batteries. Hold on... hold on. Give us a few years and we hope to have something for you.

Venkat

A 200 mile EV or a 13 mile PHEV? You choose.

The big news of the week (after Brazil loss in the World Cup and the iPhone 4 antenna issues, I suppose) is the IPO of Tesla . With a IPO price set at $17 per share, Tesla saw its shares increase to $30 at some point. On Friday, it was back down to $19.2 a share, but I think we can all conclude that this was a successful IPO. The company got some much-needed cash and the early investors cashed out. The 1st week run reminds me of another greentech "success" story- A123 Systems.

A lot has been said by various analysts on the problems with Tesla (e.g., They have not yet made money and have no chance of making money for the next 3 years), but I think the IPO shows that its possible for a small company to compete with existing players. The same can be said for A123.

Just because a company has a successful IPO does not mean that it is really successful. Tesla has a lot of problems to deal with, chief among them the fact that their cars are a tad bit expensive. Similarly, A123 continues to bleed cash and competition is increasing. Its not clear when one should consider a startup to be successful. Is it when they start becoming profitable, or is it enough if the investors, founders, and early employees make money?

Anyone who has worked at a startup knows that its a roller-coaster ride. Its not the proverbial "two steps forward, one step back". Its more like "ten steps forward, nine steps back". Everything seems magnified. A million things have to come together to be successful. Often times one has to change direction (remember that A123 was not a LiFePO4 company when they began) and this can be hard to do. Suffice to say, start-ups are not for the faint of heart. For all the guys who went through this ride, getting to an IPO will probably be considered an amazing success (well... I suppose 6 months from IPO would be a more accurate date because that is when you can sell).

For the rest, being profitable may be the criteria for success. Obviously this is no easy task. A lot has been said about the ability of a Tesla to take on, say, a Toyota (or a Tata, depending on the market) or a A123 to take on, say, a Sanyo (or a BYD). All these are valid questions and make for interesting speculation. But I think the approach taken by Tesla and that by Toyota exemplify the differences between a start-up versus a traditional giant.

We all know Tesla's approach well. They want to commercialize a pure EV with a 200 mile range. They buy laptop batteries with energy approaching 180 Wh/kg and make battery packs with energy approaching 150 Wh/kg with a total energy of 56 kWh for the pack. Assuming that their car design gets them ~250 Wh for every mile*, they are pretty much using all the energy of the battery with very little guard-banding (meaning, they use close to 90-100% of the battery capacity).

Contrast this with the news that Toyota is coming out with a Prius PHEV using a Li-ion battery. Total driving range on the battery-13 miles! Toyota argues that most commutes are less than 10 miles, but a look at the battery specs is revealing.

It appears that the Toyota battery pack is ~330 pounds and has a energy of 5.2 kWh which means that the gravimetric energy of the pack is ~35 Wh/kg! I can only assume that this is useable energy (meaning the battery will have more energy but only 35 Wh/kg is used)

Granted that Toyota would want a battery that lasts 7-10 years and so unlike Tesla, they probably are using a battery that has a lower energy than 150 Wh/kg for the pack. But one would have to think that they are atleast using something that should be greater than 100 Wh/kg. Which means that Toyota is really only using 35% of the total battery capacity (at best). Talk about guard banding!

Just so we are all on the same page, you can get 35 Wh/kg from a Ni-MH battery. One is left wondering why Toyota would want to use a Li-ion battery with such a low State Of Charge (SOC) range of operation. One can only speculate, but it would logical to think that this is one way to get the life to be better. They will operate at a lower voltage and not allow the SOC to swing too much (remember the battery rules: don't charge them too high, don't swing them too wide...).

Moreover, if the battery is only charged to a partial SOC, then if there is a safety incident (leading to, what is referred to in the industry, as a spontaneous disassembly. For the normal person, this could be called an explosion) then the lower state of charge helps decrease the impact of the incident.

All this makes sense, but what is telling is that Toyota is being very very safe in their move to a Li-ion from a Ni-MH cell (by starting with a battery that is comparable). One wonders if this is more a PR move to tell the world that Toyota is moving to the latest and greatest battery, rather than using these batteries to actually get more performance.

Compare this to Tesla which is buying laptop Li-ion batteries (which are typically the highest energy density battery you can get your hands on) and trying to squeeze as much from them as possible. One is going for incremental, the other revolutionary, one prefers an appliance-like vehicle, the other a "sexy" ride, one could be considered boring, while the other could be considered a bit brash. No prizes for guessing which one is which.

Its easy to see Toyota's point of view. All you have to do is open the newspaper (I use "open" to mean clicking on a web link) to see their recent trouble with, this time, the Lexus brand. Toyota is got to be thinking that the last thing they need is a battery-related issue. Better to be safe and boring than sexy and sorry, I suppose. They cannot afford another recall.

This difference between a startup and an established player probably resonates across all areas, not just batteries. Remember Amazon in the late 90's taking on the big box retailers, or any of the open source softwares (Firefox or Linux) taking on Microsoft.

The only difference: If you screw up your internet software all that happens if your browser crashes or worse, you are infected with a virus. If you screw up your car, things can be a little bit dicey!

Time (next 3-5 years) will tell if these newer kids on the block will succeed in being profitable. Personally, I'm keeping my fingers crossed.

Venkat

Disclaimer: I don't own shares in Tesla, A123, or Toyota (as far as I know. My retirement plan is a complete mystery to me). As a matter of fact I make it a policy of not investing in greentech. My instincts tells me that they are a good buy, but I have a policy of doing the opposite of my instincts so...

* The previous version read "250 miles for each Wh". Its actually 250 Wh for each mile.

In batteries, 2+2=1. Actually more like 1/2. Well... maybe a bit less.

This is a blog post I've wanted to write for a decade. The reason I haven't (other than the obvious problem that a decade ago, I did not know what a blog was!), is because its a tough post to write. But, folks tell me that I have a gift for explaining things (I use the world "folks" is a generic sense to indicate a number greater than 0), so I shall try.

Everyone wants to make a better battery. What they mean when they say "better" is a battery that has more energy. This is what many (not all) battery researchers are trying to do, and this is what every user wants. If you read my post titled "A Moore's law for batteries? Maybe not", you will know that the game is to find new materials that make up the anode and cathode of a battery.

The idea here is to find a new material that has more capacity than the existing material and/or find one that operates at a higher voltage. Capacity is a measure of the amount of charge (electrons) you can get per gram. More is obviously better. Capacity times the voltage is energy; for real-world applications what matters is the energy. Typical numbers for capacity for lithium-ion batteries would be 140 mAh/g for the cathode and 330 mAh/g for the anode. The typical voltage of a lithium-ion battery is 3.7 V.

A lot of research in lithium-ion batteries is focussed on increasing the capacity. There is also an active area of interest in increasing the voltage to above 3.7 V. Increasing the voltage is going to be hard (very hard), so increasing the capacity appears to be the way batteries will improve, atleast in the short-term.

Simple enough.

Those of you who are paying attention have probably noticed that for every gram of material, you only have ~1/2 the capacity in the cathode compared to the anode. If you want to make a battery with a capacity of, say 330 mAh, then you have to take 1 gram of the anode, but you need 2.35 g of the cathode (330/140). What this means is that you have a total weight of 3.35 g to get a capacity of 330 mAh. So the capacity of your battery is actually 98 mAh/g (330/3.35). So you started with a anode at 330 mAh/g, a cathode at 140 mAh/g and you get 98 mAh/g for the battery. A 2 mAh/g cathode with a 2 mAh/g anode give you a 1 mAh/g battery. 2+2 is actually only 1. Certainly not 4. Not even 2! Welcome to batteries.

If you have a new anode with say 10 times the capacity (so 3300 mAh/g) you can do the same math and you will get a cell capacity of 134 mAh/g (for a battery of capacity 3300 mAh the weight is 24.5 g). You go to all this effort to make something 10 times better and you get to use your iPhone for an extra 30% talk time. A bit disappointing! On the other hand, if you had an cathode that was, say, twice as good, at 280 mAh/g (with an anode at 330 mAh/g), then your cell capacity goes up to 151 mAh/g. Much better. 50% better. This is why most researchers want to find a better cathode. Its more bang for the buck.

All this is pretty simple. All battery folks know this. 2+2=1. End of story.

Or is it? There is another small factor that even battery researchers sometimes miss. This factor is the dead weight in a battery.

If you really want to use the anode and cathode, you need some extra real estate. Things like separators to keep the electrodes apart, current collectors to collect the current, and packaging to make sure you contain it in a neat little package. All these add weight and volume. It doesn't matter if you have 10 times the capacity in a new anode, you still have to carry this dead weight.

This is a lot like a gasoline-powered car. Only the gasoline has any useful energy in the car. But to use the gasoline, you need a tank, an engine, the wheels, the drivetrain.... you get the point.

Obviously, if you can make the weight of the rest of car as light as you can (no seats?), it helps you get more from your tank of gas. Similarly, if you can minimize the amount of unwanted weight, it helps a lot in the battery. What this means is that you try to increase the ratio of the active materials (the anode and cathode) to that of the inactive material (the separators, current collectors etc).

But there is a catch. Turns out that you can't increase the amount of the active material willy-nilly. It has to do with losses in a battery. If you put extra active material in, you have to add a bit of the inactive with it. And increasing the amount of active materials involves making the anode and cathode thicker and there is a limit to how thick these can be made before losses become prohibitive. One needs to account for these factors.

*Geek meter on*

Remember the example above where we calculated 98 mAh/g using a battery of capacity 330 mAh with a weight of 3.35 g? If you do the math on the extra weight for the inactive material, you have to add an extra ~3.35 g. You can do the math to convince yourself of this number or you can trust me. I would suggest doing the latter. So you actually only get a capacity of 49 mAh/g (1/2 of 98)! 2+2=1/2!

For you battery geeks, you can verify these numbers by calculating the theoretical energy of the battery using the 98 mAh/g and multiplying by 3.7 V to get 360 Wh/kg (the theoretical capacity of a graphite/LiCoO2 cell). You can calculate the practical capacity by multiple 49 mAh/g by 3.7 V to get ~180 Wh/kg (A typical value for a 18650 cell using cobalt oxide). Well well well... the math works, does it not?

Here is the rub. Remember the example where we had an anode that has 10x the capacity. We had a cell capacity of 134 mAh/g. If you do the calculation for the extra weight and recalculate the capacity you get only 55 mAh/g.

You have to think about this a little bit, but it turns out that if you have more capacity you will need less of the anode, so now the inactive weight becomes a larger fraction of the total weight of the battery. You could have compensated for this by taking the same weight of the anode and just talking a lot more cathode, but like I was saying, this is impossible because it increases the losses in the battery to a point where it would be useless.

So we have an anode with 10x the capacity and we gain 12% in cell capacity (and don't get me started on the voltage! That is for another post).

If you don't believe me, do the math. If you don't know how to do the math; I guess you have to believe me! It would be embarrassing if someone spots an error; but then again I'm assuming that no one has actually made it this far.

If you do the same math on the battery where instead of the anode being better, the cathode is twice the capacity, where we calculated a cell capacity of 151 mAh/g without the inactive weight you will calculate a cell capacity of 68 mAh/g with the inactive material. So you made a cathode of twice the capacity and your cell capacity actually went up by 38% (remember we calculated this to be 50% better before).

Turns out that even if you make a battery with 3300 mAh/g for the anode (in a sense, this is close to the best Li-ion anode we know of) and a cathode of 280 mAh/g (the best Li-ion cathode we know of) we get a cell capacity of 110 mAh/g. 2.2x the present-day battery. But this assumes the voltage of the two are the same. In reality the materials that have this capacity have a lower voltage, which means that the energy is not really that high. Turns out that this best base scenario battery is better by maybe a factor of 1.8 to 1.9. Meaning, this battery will approach 340 Wh/kg.

*Geek meter off*

As a matter of fact, everything else being equal (i.e., amount of inactive material), the best Li-ion battery we can dream of making in the future, based on what we know as of late June 2010, will have a energy density of ~340 Wh/kg. If you want something better, you pretty much have to work on the inactive material. All these are for cell-level numbers. If you go to a battery pack, things get even worse, but that is for another post. If someone tells you that they can make a battery where the energy is greater than this, you better dig.

Most people, including battery researchers, don't think about this extra weight. Its actually a very important factor in a battery. There is such a great focus on new materials that folks forget that reality may be as good as your simple math leads you to believe. In addition to new materials, we have to think about ways to decrease the inactive materials in a battery. There is far too little research on this and a lot to be gained from doing something about it.

So next time you hear about a new material with more capacity, ask not how much more theoretical capacity you can get, instead ask how much practical energy you actually get. Remember that you can't just divide theory by 2 to get practical; it could be less (a lot less). And don't forget the voltage. Its also critical.

To help you, here is a link to a excel spreadsheet that has a battery simulator specifically for a lithium-ion battery. I hope the mac version of excel is compatible with a PC. The sheet that has the calculations is protected. Contact me to unprotect. Let me know if you catch errors. The simulator makes a LOT of assumptions. If you want them all relaxed, contact me.

Venkat

You say potato, I say...battery?

Saw something interesting in the news on a potato battery. Its a Zn-Cu battery with the two rods inserted into a potato. Why is this new? The authors say that they boiled the potato and were able to get less resistance and more power! I swear I'm not making this up.

Check out http://jrse.aip.org/jrsebh/v2/i3/p033103_s1 for the abstract. They say its cheaper than a AA battery and can be used to power a low-power LED light. I have not dug into the numbers to see if the cost claims are right. It would seem that with the low power that one gets from each cell you will need a lot of potatoes; the authors say they need 5.

My dad is visiting us from India and is sitting across from me. He tells me that 5 potatoes in India costs Rupees 15 (~30 cents). He tells me that a AA battery is either a bit cheaper or comparable! And I still need to buy some zinc and copper (and a pot to boil the potatoes, and spend some money heating it)

I get the impression that this is sort of a cute press release of something we already know and I wonder if it solves anything. I have to boil the potato and so need energy; I gain a means of making electricity, but I lose food to do that. And we really need someone from countries in the developing world to tell us if the cost numbers are what my dad tells me they are in India.

Anyway... could not resist.

Venkat

Made in Afghanistan

Many of you have probably heard the criticism against lithium batteries in that we are now dependent on a single resource for our energy storage needs. The trouble being that we substitute from one imported reserve for our transportation needs to another. And lithium is abundant in Bolivia and China (on the Tibetan plateau)- Two countries where US influence is weak. Now comes a report in the New York Times that the US has found vast reserves on lithium in Afghanistan. See http://www.nytimes.com/2010/06/14/world/asia/14minerals.html?hp

They also found copper, cobalt, etc., but its the lithium part that is intriguing to me. Apparently the reports coming out are that there is "potential for lithium deposits as large of those of Bolivia".

Now, in the short-term (i.e., a few lithium-based batteries in cars) there is no reason for any concern or interest in this story. There is more lithium than we need. If (and this is a big if), there is a significant conversion of the automotive fleet to batteries, lithium-based ones make the most sense. In this scenario, we can get lithium limited. But we are not talking about just running out of the metal (which could happen if we convert all our cars), its more the question of: can we mine the metal at the rate we will consume it. Obviously, just because we find deposits, this does not mean we can exploit it.

We shall have to wait and see what this means to the USGS estimates of lithium reserves. And I wonder if proximity of resources will play into which countries will take a lead in battery manufacturing. In the mean time, I'm sure all you conspiracy theorists will have a field day speculating on the cause for the war in Afghanistan.

Venkat