Showing posts with label grid storage. Show all posts
Showing posts with label grid storage. Show all posts

Tuesday, November 17, 2015

A step-by-step guide to battery breakthroughs

It’s often said that breakthroughs cannot be scheduled.  I’m here to tell you that this is 20th century thinking.  The statement assumes that the word “breakthrough” is unambiguously defined.   This blog post questions that assumption and provides a step-by-step guide to achieving a breakthrough.  My focus is on batteries, but with a few tweaks, one could adapt this for other areas also. 

Let me begin by saying that in the last century there was a feeling that a breakthrough was thought to be when, for example, you discover a new material for a battery that has, say, higher energy or is safer or something.  Those sorts of breakthroughs then go through the traditional rigmarole of publications, licensing, technology transfer, peer appreciation, awards, products and the rest of the boring stuff that takes 20 years to get settled.  In the age of Twitter, Facebook, Uber, and, Snapchat, this kind of time frame is for the folks unwilling to look to new ways of achieving breakthroughs.  If you belong to this “old” club, I suggest you move on.  This guide will be of no use to you.  

But what is a breakthrough anyway?  As far as I know there is no body that proclaims something a breakthrough (a Pope for science?).  And is there really such a thing as an eureka moment?  Even if you have one, it will be a year before you can reproduce the experiment and get all the techniques in place to prove it.  And if the breakthrough is supposed to be a product, it will take you 10 more years to scale it and make it.

But what if there were a reputable publication that actually called something a breakthrough.  And then this was validated and verified by other publications saying the same thing?  That appears to be in line with the scientific method, does it not?

So, for the purposes of moving forward, let us define a breakthrough as just that: It is proclaimed as such by more than one publication.  Also to help us move forward, publications will be broadly classified as a peer reviewed journal article, or a newspaper, or a blog, or a tweet etc.  i.e., as long as the word breakthrough and your work appear on the World Wide Web somewhere, you are golden.  This guide will help you get there.

A disclaimer:  The results are only guaranteed if you follow each and every step.

Step 1:  Before you begin the research, try not to read the literature.  The peer-reviewed literature is full of things that have been tried before.  If you read them carefully, then what you are doing will not be new.  Remember this mantra (courtesy of NBC when they were promoting reruns in the 90s):  “If you haven’t seen it before, its new to you”. 

Step 2:  As you start the research, remember that facts just get in the way.  The literature is full of facts (hence Step 1).   In 1492 everyone thought the world was flat; until Columbus took to the seas.1  Then we all thought it was round, until Tom Friedman proved it was flat.  Until The Matrix came out, we thought gravity was forever binding us to the earth.  Breakthroughs happen when these laws are broken and it takes a bold person to go where no person has gone before.  To paraphrase Marsellus Wallace from Pulp Fiction, you may feel a slight sting every once in a while when it seems like you are violating faraday’s law.  Those are the facts f*ing with you.   f* facts.

Step 3:  Now that you have done your due diligence and ignored everything, it is time to focus.  Try to work on a newly-discovered material, or atleast one that has been forgotten for a while.  This is an important step.  As much as you can go after Steps 1 and 2, the more studied the material, the harder it is to prove to yourself that you are violating all the well-known laws because you are charting a new path rather than screwing up.  It’s so much easier to believe this if it’s a brand new material.  Graphene is good (not as a battery material, but remember Step 2). So are fullerenes  (granted they are old, but it seems like its time to revisit them).  Graphite, on the other hand, could be bad; unless you plan to use it in a new way; in which case it can be good.  Lithium metal is ALWAYS good; but if you go this route you really need to get religion on Steps 1 and 2.  

Step 4:  As you start getting data on the new invention, revisit Step 2.  Revisit it often, especially when you feel down. 

Step 5:  Time to start writing the paper.  Always state that your invention is better than Li-ion.  The only way to get anyone excited is to say that.  This may sound hard, but it is not.  There are many metrics that need to be satisfied for a battery, including, energy, power, charge time, cost, life, safety, low temperature and high temperature stability.  If you think that you have something that looks better in any one of these, you are doing better than Li-ion.  Cost is the easy one if all else fails.  You can always safely say something like “our preliminary cost estimates suggest that the battery will cost less than something-small/kWh”.  Other end of the spectrum is energy, which is the hardest.  If you go down this path you really need Step 6. 

Step 6:  Always confuse energy with power.  It’s completely appropriate to say “Our pixie dust battery can discharge a factor of 10 faster than Li-ion, therefore EVs based on pixie dust have a longer driving range comparable to Li-ion EVs”  or “our batteries can be charged in 5 minutes, providing more energy than any battery known to man or aliens. On a separate note, we only seem to get one cycle from our battery; we think this has something to do with aliens” 

Step 7:  The paper is ready and it is time to submit.  Never send the paper to a journal that specializes in publishing papers in batteries.  This will get your paper into the hands of traditional battery-types who remember past history, know what works and what does not, and have a strong scientific foundation in the field.  Such knowledge can be an impediment to your out-of-the-box thinking.  Remember Step 2.  Always choose a journal that is disconnected from the battery field. 

Step 8:  With the paper coming out, it is time to prepare for a press release.  Remember that the press wants to hear that this is a breakthrough.   So despite what the peer-reviewed paper proves, make sure you call it a breakthrough at the press release.  Remember that Steve Jobs did not really have a working iPhone when he announced it to the world, and declared that they would ship in 6 months.  If it is good enough for Steve, I’m sure it is good enough for you.  So don’t be shy in telling the press how great your battery will be.  Make sure that you give interviews to numerous publications.  Remember our definition of a breakthrough:  you need multiple publications to say it is one.  So target many outlets. 

Step 9:  The day has arrived; the publications are out; and you have spend the better part of the day googling yourself to see how far the word has spread.  This is the day when you may hear skepticism (some contained within the articles and others in emails addressed to you).  Remember Step 2.  Remind yourself that the iPhone had many critics (e.g, the proximity sensor will not work.  Who would want to surf the web on a phone anyway? Atleast they got the first problem right!).  If it worked out for Steve Jobs, then it could work out for you too.   

Step 10: Remember “Practice makes perfect”.  So go back to Step 1 and repeat. 


All the best. 

Venkat



1.  Now, you may search Wikipedia, or read some articles that claim that the earth was known to be round since before the Common Era.  But that is because you are reading the literature.  Did we not drill into you in Step 1 that this was bad!   Now stop looking up stuff and get with the program.    

Sunday, November 7, 2010

This week in sulfation

First off, I have to apologize to all 7 of my regular readers for not making a post in a while. I have been busy and hence the hiatus. Between watching reruns of Curb your Enthusiasm, election ads, and the Giants world series games, I need more time in a day. But all good things have to come to an end. I hope to resume regular postings starting now.


This week, I was rudely reminded that just because you know how batteries work does not mean that you can deal with a battery problem. But first some background.


Subaru's are excellent cars and I would highly recommend buying one. They are well made, they run great, and they hardly give you any problems (touch wood). But Subaru's also have small quirks that can be bewildering and a bit infuriating. Like not having a remote trunk opener or having only 3 wiper speeds. Or having this one light that does not turn off when the ignition is off and is so hidden that you can't tell that its on in the first place.


The light serves no real purpose, except to make sure to keep the battery industry thriving. Long story short, "someone" left that light on on Sunday (and I'm not saying who).


A bit more background: My car is 7 years old. My battery is (or was as of yesterday, but I'm getting ahead of myself) the original battery.


Monday morning at 7 AM I get to my car to start driving to San Francisco Intl. to catch a flight to Washington DC to be at the center of the action during election day (Tuesday). I was using a meeting on energy storage for grid applications (think storing solar and wind electricity) as an excuse to get someone else to pay for the trip. I was going to be gone all week.


Except my grand plan was crumbling because my car appeared to have a dead battery. I quickly realized what had happened.


When professionals are thrown into a crisis, they do not think, they react. Think Jason Bourne coming across an assassin or Neo coming across Agent Smith (in the Matrix).


Just so there is no confusion: I consider myself to be a professional.


In a matter of seconds the pieces started to fall into place in my brain without any real thinking. I knew my battery was probably pretty sulfated (and corroded with lots of shedding, for that matter). I opened the hood, took one look at the battery and I could literally see the sulfation on the plates (through the grime that covered the hard polypropylene battery shell). I knew that if I jumped the car right away I had a chance of saving the battery. I also knew that if I left it in the discharged state all week, I would probably sulfate it more and maybe end up killing the battery altogether.


To remind you, when you discharge a lead-acid battery you form lead sulfate. Lead sulfate is pretty insulating. But it has a bit of solubility in the electrolyte (sulfuric acid). This leads to some Pb2+ ions in solution. When you charge, these Pb2+ ions allow you to get back to the charged compound. As you react the Pb2+, more lead sulfate dissolves.


Sulfation is a process by which the lead sulfate starts to agglomerate together to form large crystals. This leads to a loss of surface area. What this means is that you don't have enough area for the electrolyte to dissolve the lead sulfate to form Pb2+. So charging the battery gets harder. Sulfation takes a while; maybe in the order or days. Not hours.


Sulfation is reversible. But you have to charge the battery very very (very) slowly so that you slowly dissolve the large crystals of lead sulfate to Pb2+ and convert them back to the charged state. But, who has the patience to wait all week to charge a battery!


What this means is that discharged lead-acid batteries are bad news. You need to avoid them like the plague.


So the path was clear: Get a jump start, drive the car for the next hour and half to SFO and hope that the battery gets its life back. Like I said, a professional does not think. He/she reacts.


But a professional also recognizes his/her limitations. In my case, my limitation was that I was really cheap and had not invested in jumper cables or AAA insurance. A professional also typically has no real friends. I knew that none of my "friends" would be willing to stop by to give me a jump at 7 AM.


So I reacted to this problem by taking BART (i.e., public transport) to the airport.


I dont know if you guys encounter this, but sometimes when you have something on your mind it seems like the whole world is starting to think about the same thing. So here I was thinking about sulfation of lead-acid batteries and at this conference on grid storage, there was all this talk about the UltraBattery (this is a trade name) as a means of preventing sulfation. There were actually two talks completely dedicated to it.


I spoke about this advance a little while ago. The concept is to add some carbon into the negative plate when you make the electrodes. Everything else stays exactly the same. But for some magical reason the sulfation decreases significantly.


The talks were showing data where the battery was being cycled a little bit (like a Prius battery does) where the battery without the carbon tanks after a few hundred cycles but the one with the carbon works much better (thousands of cycles). Apparently, the carbon solves the sulfation issue.


There is a variant of this idea which involves connecting the negative plate in parallel to an electrode made of activated carbon. Activated carbon by itself is used to store energy in the double layer (i.e., a double layer capacitor). So essentially you are connecting a battery electrode in parallel to a capacitor electrode in both these configurations.


What was amazing was that they really had no idea why this was happening (although its been a few years since this first came out). DOE is actually funding a project to try to get to the bottom of this advance. Its sad but true- there is a fundamental change in a 150 year old technology but we have no idea why this change occurred.


Some things in life are really hard to reconcile (e.g., is there a God? why does EVERYBODY make more money than Scientists?) but this problem is not in the same class. I believe that this lack of understanding comes down to limited funding for research combined with the "herding" of research topics.


Lead-acid batteries are cheap. The one that I ultimately replaced my car with cost me $165/Kwh. Assuming I got ripped off (is that even an assumption for things car related?) it stresses the point that these batteries are cheap. Adding a few percent of activated carbon to the paste is not going to break the bank. All through the conference I kept wondering why lead-acid's are not being made with a bit of activate carbon to ensure that sulfation is not a problem.


As an aside, the cheapest battery we know of is the lead-acid battery. For grid applications, the thought is that we need batteries that cost less than $100/kWh. Something pretty radical has to happen for us to make these cost numbers. Making batteries the way we have made them in the past will not allow us to get there. But this is for another post.


So would adding a bit of carbon result in the battery lasting the life of the car (say 15 years)? The company that is commercializing this says it could last 7 or maybe 15. Meaning: they have no idea! Problem with not knowing why something works- there is no way to predict how long it will work. Moreover, the data they show is based on Prius-like cycling. My car does not have the same cycling profile. Unless we understand what is going on, we have no way to knowing how changing conditions will change performance.


In time, this data will show up and we will know if we will can make a better lead-acid car battery. But wouldn't it be better if we understood what was going on?


Truth be told, I'm not at all convinced that my battery was sulfated and could have been saved with a timely jump start. It lasted 7 years! That's a long time. Plates corrode and they shed. Maybe I ought not to expect more from my energy storage devices.


But being able control failure modes in batteries is crucial in ensuring that we can move to electric drive. And they will be crucial if we ever want to store the electricity from the sun. Solar panels last 25 years; do you really want to change your batteries every 5 or 7 years?


But to control the failure, you first need to understand them. And in many cases, we don't quite have life of batteries pinned down. They change with chemistry, multiple failure modes occur at the same time, and in some newer chemistries we just haven't had the time to collect the data to see what the failure mode is.


So we have clues and hypothesis for failure, but we can't quite predict failure rates with cycling conditions. There is no cycle/calendar life simulator for batteries.


Actually that is not true. There are many many life simulation tools for batteries. But none of them actually work!


To me this incident highlights the importance of fundamental research to understand real-world problems. There is quite a bit of fundamental research; and there is no dearth of real world-problems. What we don't do enough of is linking the two (The Program at Berkeley is unique in that its the only one that does this in the whole field of batteries).


It also highlights the fact that I really ought to stop being so cheap, spend some money, and get jumper cables.


Venkat