53. HOW YOUR BATTERY DETERMINES YOUR PHONE'S FASHION           

Most of us recall the days of the flip phone, a mere decade ago, when the battery was small, a puny 800 mAh, yet it lasted days. Over these past several years, our phones got smarter, they got sophisticated, and the battery took the brunt of this evolution. While nearly every component inside the smartphone can boast of the power of Moore's Law (doubling power every about 18 months), the battery is the only outlier that has been progressing at a snail's pace. The result is that the battery is now the bottleneck in the evolution of mobile devices -- hence the incessant complaints from end users.

So let's look at the evolution of the battery in the last two years, and how it has impacted the design and functionality of the modern smartphone. The following chart shows the energy density in Watt-hours per liter (energy per unit of volume) plotted against the charge capacity (in A.h) for a survey of smartphones released in 2013 (red squares) and 2014 (blue dots). 

We observe two trends. The first trend is the migration of battery charge capacity to the right, in other words, the charge capacity increasing from about 2.5 Ah to about 3.0 Ah, or an increase of about 20%. This trend clearly gives the end user more battery life and hours of use per day. The second trend is that the energy density also has increased, from a range of 530 - 550 Wh/l to now a range of 560 - 600 Wh/l, or an increase of about 10%. 

Now let's give this a bit more thought. The capacity went up by nearly 20%, but the energy density went up by only 10%, so the difference had to be accounted for by an increase in the volume of the battery. In other words, the battery had to either get longer/wider or thicker. However, the fashionable trend is now for high-end smartphones to get thinner. Many smartphones are now dipping below the 7-mm thickness mark. For these thin devices, the battery had to grow in length and width, in other words, only large screen phones (greater than 5-in) can now accommodate these larger battery capacities, especially 3.0 Ah or more.

So in summary, the battery trends have had a huge impact on the form factor of the modern smartphone and its fashionable looks. In particular, because energy density is not keeping up with the rise in required charge capacity, the smartphones essentially got bigger. We witnessed in 2014 a rise in the number of smartphones that sport 5.5-in and even 6-in screens. 

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

52. YOUR MOBILE FAST CHARGING OFFICE AT YOUR FINGERTIPS    

You are mobile. You travel. You own a smartphone, a tablet, and a laptop. You are always on the lookout for a power outlet that is not used by a competitor, i.e., another mobile traveler like you. You hate compromise. You need fast charging in each of your mobile devices but until now, all you had were promises. 

You can now travel with a fully powered office in a backpack. One that can hold your mobile devices and charge them multiple times. And if your office runs out of battery juice, refill it in minutes with Qnovo's fast charging technology + never compromise your battery's longevity. This is quality that you should expect! No compromise, no lies, no cheating.

So if you want one of these neat backpacks and like to support innovation, get it here at Indiegogo.  You can get this entire backpack from AMPL and take your office with you for only $225. Or you can get a kick-ass charging booster for only $49 with 5,000 mAh of battery capacity enough to charge your iPhone three times in a row. And when you need to charge your booster, you won't need to wait for long. This booster charges at a phenomenal 1C charge rate, which means you will go from a low battery level (20% charge) to a high charge level of 75% in less than 30 minutes. That's 2X or 3X faster than what you will see anywhere today. That also means you can get enough charge in your booster to recharge an iPhone 6 battery in less than 20 minutes! This is mobility that totally frees you from the wall socket!

And if you are ever in doubt about the charge time and the longevity of your battery, here's some real measured data on its performance. Unlike others, we are straightforward about the high quality that we deliver. No tricks, no cheating! You get what you are promised and what you expected when you purchased the product. 

This first curve shows the actual charge time for the battery. Zero to 50% in 30 minutes. Zero to 80% in a little over 45 minutes. At the 80% charge level (or state of charge), the booster battery holds 4,000 mAh, enough to recharge an iPhone 6 twice and more.

This second graph shows the longevity (or cycle life) of the battery. You will charge your battery over 500 hundred times (cycles) before the battery loses a mere 10% of its available charge capacity (the blue curve). If you were to do the same fast charging using conventional CCCV charging, then the result would be disastrous: Only 100 cycles, or a couple of months of operation before you declare your battery wasted and needing replacement (that's the green curve in this chart).

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

51. THE RISE AND FALL OF A123 SYSTEMS                                              

On 24 September 2009, A123 Systems become a public company trading under the ticker symbol of AONE on the NASDAQ. Its shares soared on the first day of trading closing the day at $20.29 per share, making the company valued at nearly $1.2 Billion. It had posted revenues of $36 million during the first six months of 2009, mostly in service revenues. Its marquee investors included names like GE, Qualcomm, and others who, along with the US Department of Energy, had collectively invested over several years in excess of $500 million into the company.

Nearly 3 years later, on 16 October 2012, the company filed for bankruptcy after missing a $2.7 million dollar in interest payment on its outstanding debt. In December of that same year, a bankruptcy judge approved its sale to Wanxiang Group, China's largest auto parts company, for $257 million. Why would a darling company of the CleanTech industry and Wall Street fall so fast and so hard, and what lessons should the industry heed?

Let's start with a quick recap of the company's history. It was formed in 2001 as a spin out from MIT to commercialize a new material system, called nano phosphate, upon which lithium-ion batteries could be built. The background to this new material lied with the safety and reliability issues that plagued the lithium-ion battery industry in the previous decade. The too-frequent fires at battery factories in Asia and product recalls on laptop batteries made the lithium-cobalt-oxide (LCO) material system unsafe at least by reputation, and certainly unsuited for the envisioned electric vehicles of the future.  By 2006, the company had collaboration agreements with the US Advanced Battery Consortium (USABC), an automotive consortium bringing together Detroit's Big Three, along with the US Department of Energy, and was already building battery packs using its proprietary lithium-iron-phoshpate as its primary cathode material. The new batteries were supposedly safer, had very long cycle life (upwards of 2,000 cycles) that was suitable for automotive warranties, and were capable of handling large current spikes -- in battery parlance, it is known as power capabilities. But as time would prove, LFP, as this new nano phosphate material system was known, suffered from lower energy densities compared to the material system it was trying to displace. 

But any shortcoming on energy density was not sufficient to detract the company from focusing on electric vehicles (EV). By 2008, it had signed agreements with TH!NK to supply batteries to this Norwegian electric-vehicle maker. The next year, it had inked deals with Chrysler, Shanghai Automotive Industry Corp., and Fisker. The future was bright and the potential was enormous. It was time for an IPO.

Underlying this exuberant optimism, especially in 2009 when gas prices hit nearly $5 per gallon and electrification of cars was the future, were some weak fundamentals. Yet, they were either unknown or ignored by many...ultimately, these weak fundamentals led to the demise of the company and its sale. Leaving execution out, these weak fundamentals boil down to choice of technology, product and market.

First, there was and still is a mismatch between the technology of choice, LFP, and the requirements of the EV market. Electric vehicles required a long driving range, which in turn dictated a high-energy density battery technology. LFP has a substantially lower energy density that the LCO material system, and it was doubtful that LFP would improve in time to shrink this gap. In other words, LFP was not suitable to build batteries capable of reaching a 200-mile driving range. For comparison purposes, the energy density of the A123 material system was nearly ⅓ that of the batteries used in the Tesla Roadster -- the first model of Tesla Motors. A123, and its list of partner EV manufacturers, were willing to compromise driving range for better reliability and safety. Tesla in contrast, made driving range a key priority for its cars, and elected to improve the safety of the battery through clever engineering designs of its battery pack, i..e, in the mechanical design as well as how the electronic systems safely manage the lithium-ion cells. Nearly a decade later, experience shows that driving range is of paramount importance to drivers of electric cars, and that LCO-based battery packs can be made very safe.

Comparison of select battery properties used in electric vehicles.

Second, A123 Systems was fundamentally a battery materials company. That's where its innovation lied. As such, it focused primarily on improving the design and manufacturing of its battery materials. Yet, the battery pack in an electric vehicle was a complex integrated system that brought together both the battery and its materials along with a sophisticated battery management system (BMS), i.e., the electronics and software that control the battery's performance and reliability. A123 Systems largely left the design of the BMS to its customers. That meant that the overall battery pack system could not be fully optimized as long as its key ingredient subsystems were designed by different parties. In contrast, Tesla elected to design and build the entire battery pack themselves, using a battery cell design (18650) that had been around for at least a decade. In other words, in the complex balance of battery materials vs. system design, where does a company put its emphasis? History now shows us that the system-emphasis proved to be more optimal. Materials in general take a long time -- upwards of a decade -- and large investment capital to reach commercial maturity. Systems development tend to reach maturity at a faster pace.

Third, or perhaps it should have been first, is cost. The 18650 used in the Tesla models was already being used in millions of laptop computers. It was relatively inexpensive to manufacture. It made sense for, at the time, a nascent electric vehicle company to leverage the scale that the PC industry brought to batteries. In contrast, A123 Systems and all the supporters of LFP had to start from scratch: Build a manufacturing infrastructure, develop an efficient supply chain, establish scalability and ensure reliability. None of these are easy tasks, and they tend to take time and a lot more money. Ultimately, these delays and investments show up as losses in the company's financial statements.

Lastly, it was about the initial choice by A123 and its partner customers of targeting electric vehicles for the mass market, which meant pushing for affordable car pricing thus introducing serious cost pressures on the supply chain. The electric vehicle market is still in its infancy, even after several years of government incentives and increasing regulation. Therefore targeting electric vehicles for the mass market was a tall order, especially when performance and overall cost were not matching those for traditional vehicles with an internal combustion engine. It greatly increased the challenges that the customers of A123 Systems had to overcome. Over the past several years, we saw both TH!NK and Fisker go bankrupt (Fisker was too acquired by Wanxiang).  GM and Ford ultimately chose batteries from LG Chem, a large industrial giant that was willing to underwrite the necessary capital to penetrate Detroit...a luxury that a comparatively small company like A123 could not undertake. Once again, Tesla made a different choice of targeting niche markets, first with an expensive sports car, then going after the high-end luxury market. Both of these choices relaxed the cost constraint and allowed the design and manufacture of an electric vehicle with few if any compromises compared to their combustion-engine counterparts.

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

50.  MOBILE USERS: REBEL AT THE BATTERY COMPROMISES      

Our Silicon Valley newspaper, the San Jose Mercury News, published this morning an article on the all-known battery blues. We have heard this story before. Your battery runs out before your day is out. The paper quotes Prof. K.M. Abraham, from the Center for Renewable Energy Technology at Northeastern University in Boston, saying that the present battery material system is reaching a dead end and that a new material paradigm is needed. The paper continues to describe how users are now lugging with them battery bricks; this is jargon for these extra heavy battery chargers that you can carry with you in case your phone battery dies in mid-flight. 

But these bricks are incredibly impractical. You pay hundreds of dollars for your thin and slim smartphone, yet you are willing to compromise by carrying these heavy battery bricks. The inexpensive versions from China (retailing somewhere near $20) don't last much. Ones with higher quality can be quite expensive, with some even breaking the $100 mark. This is the definition of a poor compromise. Consumers deserve better!

The battery materials and chemistry are not evolving fast, their energy density is not increasing at a rapid rate, and they are falling short of providing higher capacity batteries. For the time being, smartphones seem to be limited to around 3,000 mAh as a maximum capacity. At this capacity, the energy density is state-of-the-art at more than 600 Wh/l, but the batteries seem to last a full day at this capacity. The iPhone 6 Plus and the Sony Xperia Z3 are examples of devices with approximately 3,000 mAh of capacity, and they are receiving rave reviews.

So what solutions can be acceptable to consumers and involve no compromise? 

First, make 3,000 mAh batteries the standard across smartphones. Yes, that also means using the highest possible energy density, presently around 600 Wh/l. 

Second, make fast charging ubiquitous. If consumers can fast charge their mobile devices, then their anxiety about battery life is greatly diminished, if not eliminated. What is fast charging? Fast enough that you can charge your phone in about 30 minutes; if not all the way to 100%, then at least to 80%. This is the level when consumers viscerally feel that they have plenty of charge in their battery. 

Third, give the consumers a great sense of satisfaction that their batteries will have ample longevity and warranty, in other words, give them 800 cycles or more.  Don't cheat them with 500 cycles. These three elements can already be delivered to consumers today -- the technology already exists.

That's the definition of no compromise. As a consumer, let your carrier know. Demand a battery with no compromise. Let your device manufacturer know. Vote with your wallet and rebel against the lousy battery choices that the industry keeps entertaining.

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

49. THE BATTERY COMPROMISES OF MOBILE DEVICE MAKERS            

We have seen time and time again: the consumers' #1 priority is the battery. That's right, not 4K video, not 40Mpixel cameras, or a power button to operate with your middle finger...it's the battery. So let's see how the leading models of 2014 fared on battery life.

I put side by side the iPhone 6 Plus against the major Android phones, namely the Galaxy S5, Sony Xperia Z3, LG G3, Moto X, HTC M8 and a newcomer, the OnePlus One. Let's plot for each of these smartphones the measured use time, specifically, the numbers of hours each device lasted in web viewing over LTE. This is a fairly good estimate of the battery life. On the horizontal axis, I show the battery capacity in mAh. So what observations can we make?

First and foremost, what is plainly obvious to all mobile device users: The bigger the battery capacity, i.e., the more mAh, the longer your device will last. The Moto X has the smallest capacity, and the Xperia Z3 has the largest capacity. Yes, you guessed it, the Z3 outlasts the Moto X by nearly 5 hours!

Second, we see that there is a kind of linear relationship between capacity and hours. This is math lingo that says that if we increase the battery capacity by a factor of two, then the hours of use will also increase by the same proportion, in this example, also a factor of two. There are some small exceptions but in general, this says that there are no games one can play: it's a one for one relationship between battery capacity and hours.

So given that all of these phones offer nearly the same screen size (5 to 5.5 inches), why is it that these different manufacturers have such disparities in their batteries? Why don't they standardize? After all, they all use the same radio chips and processor chips...why do they tinker so much with the battery with so little to show for?

There are several reasons. One, engineers like to customize if they are allowed to customize. So first thing they do is customize the size of the battery to fit the desired phone look and feel. Second, they need to balance a number of competing specifications. For the battery, these competing specifications include capacity, but also how fast they can charge the battery, and how long the battery will lasts (also known as cycle life).

Unfortunately, for these engineers, it's a game of whack-a-mole. If they increase the capacity, as Sony  did with their Xperia Z3, then they need to drop the charge rate. The Sony Xperia Z3 has one of the slowest charge times in the industry. Motorola engineers went in the opposite direction. They decided to charge faster than their competition, but to do so, they had to drop the capacity to a measly 2300 mAh, making the Moto X the phone with the worst battery life.

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

48. THE LITTLE COMPANIES THAT COULD                                            

Imagine a world where your device, whatever it may be, has a source of energy -- may be a battery, may be not -- that lasts, I mean lasts to the point you don't think about the period. It lasts in its operation and lasts in its longevity. If you ever find yourself with a low energy level, and I mean ever, then it's only minutes before your device is recharged. And yes, the energy source is so tiny that you can't even point at it. I know, this is in a distant universe, but why is it so distant? After all, a drop of gasoline has enough energy to power a mobile device for days or weeks, and one can replenish this source of energy in no time. And you don't have to worry about it going bad. So will we ever get there? Yes, with time, patience and lots of effort, in other words, dollars, sweat and time. You have got to believe that StarTrek will happen in this distant future, and we will have dilithium fuel to power everything.

But who's participating in this effort? Is there hope? This blog sheds some light on the numerous companies, many of which are innovative startups, that are trying to change the world on this front. Two types of energy storage seem to garner interest and development effort: Fuel cells and batteries. I will focus here on batteries, especially lithium-ion batteries that are applicable to mobile devices.  Innovation and development are loosely broken into five categories as shown in the figure below.

Developing new anode materials is one of the prime focus areas for several startup companies. This is aimed at raising the energy density beyond the wall that is now towering over the industry.  Companies such as Amprius, Enevate, SiNANOde are examples of startups focused on silicon-based anodes. Quantumscape, a spinout from Stanford University, is focused on a entirely new structure and material system with high dielectric constants. Envia seeks to develop higher voltage cathodes -- by raising the voltage, one also raises the energy density. Lab demonstrations have been very promising at many laboratories but scaling to real-world production remains a tall task for these companies.

Electrolytes is another fertile area of investigation. Plenty of effort is aimed at replacing the liquid or gel-like electrolyte medium by a solid-state material with conductive properties for the ions. SEEO, Sakti3 and several other companies are working on launching batteries with solid-state electrolyte. It's a promising area but serious limits still remain including scaling to cost-effective volume production.

Improving the design and manufacturing of batteries is also another area of great interest. Enovix is combining newer materials that can be deposited and manufactured using semiconductor-like processes. Imprint Energy seeks to screen print batteries in what should be a cost-effective and repeatable process.We, at Qnovo, are focused on clever control systems and software to open up the operating envelope of batteries.

There are tens of startups working on new battery technologies. Inevitably, I have missed in my brief list several others that are also leaving their mark on this field. Collectively, the contributions of all these companies will ultimately elevate energy storage to an entirely new dimension. It will take time but the goal is achievable.

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

47. THINNER IS NOT BETTER                                                             

What does the new iPhone 6, Samsung Galaxy A7, Huawei Ascend P6 have in common? First, they are amongst the thinnest mobile smartphones ever made. The iPhone is 6.9 mm. The A7 is a mere 6.3 mm and the P6 comes in at a paper-thin 6.2 mm. Thickness, or lack thereof, does make these devices quite elegant. 

The second thing they share: They have amongst the smallest battery capacities, and consequently struggle in delivering a long battery life. In comparison, the smartphones with the best battery lives, for example, the Sony Xperia Z3, clocks in at 7.3 mm, a whole millimeter thicker than the Samsung device.

Naturally, a thicker phone allows the use of a thicker battery. That extra millimeter may not sound a lot, but it adds an extra 15-20% of capacity to the battery. That translates to about 350 - 500 mAh more in capacity, or 2 to 4 hours of additional use time.

But the impact is more meaningful than that. A thin battery suffers from a dramatic drop in energy density. Let's look at the chart below that shows a survey of several batteries from one of the leading manufacturer. It shows how steeply the energy density drops with every millimeter of thickness that is removed.

Let's take the Sony Xperia Z3 as an example. It is 7.3 mm thick. Its battery is about 4.5 mm thick. Its energy density is nearly 600 Wh/l. Shaving one millimeter from the battery thickness yields a serious loss of energy density, down to about 500 - 525 Wh/l, or about 15%. This is in addition to the volumetric loss of ~20% that I mentioned earlier. In other words, the total loss of capacity is now approaching 35%, or more than 750 mAh, corresponding to several hours of use time that the end consumer no longer gets to have. Put a little differently, the cost of shaving one, just one, millimeter of thickness from your elegant smartphone device is equal to 5 or more hours of lost use time to you. So, next time you go shopping for a smartphone, ask yourself a simple question: Elegance vs. Practicality? If you favor elegance, then go thin, but now you can't complain about your battery.

But why is the effect so dramatic? If you recall from an earlier post, a lithium-ion battery is made of alternating layers of cathode-anodes separated with a "separator" material. The active material, i.e., the stuff that is actually responsible for storing the electrical charge constitutes only a fraction of this layered arrangement. In other words, there is an "overhead" of extra material that needs to be there, but does not really contribute to storing energy. When the battery becomes thin, the contribution of this "overhead" becomes much more prominent, thereby reducing the amount of active material available per unit volume, and hence reducing the energy density. It's pure geometry. 

Of course, one can try to increase the amount of active material in this small volume. For example, one can "compress" more of the graphite material in the anode. But these come at a cost: the charge rate and the cycle life of the battery drop very rapidly. So once again, this goes to illustrate how the battery manufacturers are hitting the wall!

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

46. ...AND THE SURVEY SAYS:                                                 

This year's Consumer Electronics Show (CES) in Las Vegas, which is just ending, has given us, consumers, a lot of new gadgets to ponder. We saw a gamut of new toys from larger TVs, 4K video, curved screens and curved smartphones, to wearable devices and IoT -- a new acronym for Internet of Things, or perhaps better said as "connecting all things", but that would be a CAT; we wouldn't like that!

But what do consumers really, really care about? We no longer have Steve Jobs to presciently guide the consumer flock to where they should spend their dollars. So, marketing experts resort to surveys, of all kinds. So what are these surveys telling them.

Fortune and SurveyMonkey released a poll at the 2015 CES show. They asked "what new or improved smartphone feature are you most excited about?". The #1 answer was, yes, you guessed it right, "improved battery life." By a 2:1 margin, it led the next best wanted feature: faster processor. The same survey also showed that nearly ¾ of all respondents were not likely to buy a fitness band or smart watch in 2015. So if surveys are such a guide, why are the consumer electronics manufacturers spending huge development dollars on smart watches and so little on making their batteries perform better? 

A 2014 survey by The Guardian in the UK shows that consumers are asking for better batteries ahead of all other features

The Guardian in the UK published earlier in 2014 another survey asking consumers to rank a number of features in smartphones. It also found that a better battery came in as the #1 desired feature. So I ask again, why aren't the electronics manufacturers seeking the best innovations and technologies to make batteries better? I will offer a few suggestions.

First, the battery problem is not easy to solve. Electronics manufacturers have plenty of smart electronics and software engineers, yet, more often than not, they lack in the critical skill of battery chemistry. It was not until the last decade that engineers and scientists wanted to work on batteries. So, these large consumer electronics manufacturers have to seek solutions elsewhere. They are not finding the answers with the large battery manufacturers in Asia who themselves are struggling with making better batteries. Many electronics manufacturers are not organized nor well suited to efficiently work with innovative startups that have creative solutions for this problem. So they are stuck and keep iterating around silly solutions.

Second, there is a lot of NIH in the industry -- that's an acronym for Not Invented Here. Engineers are an amazing creature. I can say that because I am one of them. On one hand, they have an imaginative mind and are great at what they do, but on the other hand, their ego can stand in their way and that prevents them from seeking solutions that may not have been invented by them. I am, of course, crudely generalizing and there are lots of exceptions. But the degree of NIH is climbing in the industry especially as the mobile industry is rapidly commoditizing placing enormous pricing pressures on the manufacturers.

The net result is that the rate of innovations is beginning to slow down, and the industry is beginning to fall into a vicious circle of introducing silly features that consumers do not care about, and that's precisely what the surveys are saying. Time will be a judge of the new wearable products. But one thing I can tell the manufacturers now: Let us help you fix the battery problem!

© Qnovo, Inc. 2015 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

45. LITHIUM IS GOLD                                                                        

You have got to be saying, "Wait!", this is non sense. That perennial Periodic Table that we all took in high-school chemistry said that Lithium had an atomic number of 3, yes three, and Gold had an atomic number of 79. Gold is 28 times heavier than Lithium...are we preaching alchemy?

First, let me just say that this not a metaphor for lithium bringing financial rewards. Lithium is fairly abundant in the Earth's crust in the form of lithium salt deposits, and second, I have yet to see a battery manufacturer that is reaping huge financial profits. Financial margins in battery manufacturing are dismally challenged, and the financial markets have not rewarded such performers. Dare I say A123, an old and no-more darling of Wall Street?

This is much simpler. You see, graphite turns into a pretty golden color when lithium diffuses and intercalates inside its carbon matrix. Think of the graphite as swiss cheese. Naturally, this is not evident to most of us since the battery is actually sealed and we don't see what happens inside. But should you develop a transparent battery, then its colors shine. This is precisely what researchers from Michigan did, and while they were at it, they took some nice photographs of the graphite as it turned from black to gold.

Source: S. J. Harris et al., Chemical Physics Letters, 2010 (pages 265 - 274)

The first photograph in the sequence on the far left shows half of a small battery as we look through a transparent window. The battery is discharged, in other words, the graphite is empty of lithium ions. As the battery is slowly charged, lithium ions move from the cathode, the other electrode, with the direction of motion upwards in the screen. The lithium ions are physically intercalating themselves inside the carbon matrix. In the process, the graphite electrode swells to accommodate the physical presence of these lithium ions. This and the chemical bonds that the lithium forms with the carbon change the nature of the material, and consequently its optical properties. The graphite slowly turns from black to reddish and ultimately to gold color. Adding more lithium ions to the carbon ultimately results in the lithium depositing on the surface of the carbon as metallic lithium which has a silver-like appearance.

Now, take a deep look at the third photograph from the left. The bottom of the graphite electrode is red, indicating that it is beginning to fill up with lithium ions, yet the top of the electrode is still black.   This is called diffusion: Put a little red dye in a glass of water and see how it slowly diffuses into the surrounding water. The diffusion of lithium ions creates a steep gradient across the thin electrode (only 0.8 mm thick). Consequently, this puts enormous mechanical stresses across the graphite and is one of several causes of battery failure. This gradient, and consequent battery degradation, is the result of how you charge the battery, and in particular CCCV and its variants such as step charging.  You see, CCCV has no idea what may be the diffusion characteristics of the lithium ions. Charging at faster rates only makes this situation worse unless more clever charging algorithms are incorporated to mitigate this and other degradation effects.

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

44. YOUR BATTERY IS FINE, YOUR APPS ARE NOT!                               

It is nearly guaranteed that every consumer has looked at least once at their mobile device in total bewilderment, wondering how their battery came to be depleted. If it happens more than once, they begin to suspect that they battery is defective or has gone bad. In reality, before suspecting that the battery is defective, they should inspect their power usage, examine whether an app has gone rogue and is responsible for the battery drain. Naturally if you battery is old, say one or two years, then you should suspect that the battery may need replacement. So let's do a couple of debugging checks.

1. Has your battery gone bad? 

A few Android phones are capable of reporting the capacity of the battery. For example, dialing the following sequence *#*#7378423#*#* on your Sony Xperia Z device gives you access to a host of tests including reading the actual battery capacity in mAh. But if your mobile device does not have this feature, then one simple trick is to measure the charge time of your mobile device and compare it to the charge time when it was new. Yes, I know, it is not ideal but it gives a good indication of lost capacity. Make sure your screen is off, all of your apps are shut down, and you use the same AC adapter rating. If your measured charge time is 20% shorter than what you measured for a new phone, you can suspect a bad battery.

2. Do you have a rogue app?

Unfortunately, some apps especially in the Android universe are improperly designed and can be suspect of excessive power usage, and consequently faster battery drain. Additionally, the consumer behavior has a big impact on battery drain. If your app is using the radio or GPS (location services) continuously, your battery will drain fast. The good news is you can now detect this in both Android as well as iOS 8.1.

In Android, go to Settings>Battery. In iOS, go to Settings>General>Usage>Battery Usage. You will see screens like the ones shown below.

Both screens will list the approximate usage pattern as well as the apps or processes that are consuming power. I say approximate because each operating system will add its own interpretation on top of inexact measured battery numbers, but the screens do offer a reasonable guidance on what is draining your battery charge. In the case of Android, you will notice that "Screen" seems to top the charts. That's because it does take a lot of power to maintain the lighting of the LCD screen. Scroll through your list and identify what is potentially a rogue app. Then either delete it and reinstall it, or if you can live without it, then do so. In some cases, your rogue app may be operating constantly in the background, so be sure to turn off background services.

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

43. ARE LITHIUM ION BATTERIES BECOMING UNSAFE?                             

I just returned from travel in China. The Chinese airport authorities take very seriously the transport of lithium ion batteries on board of commercial airliners. If a passenger is carrying an unknown or unlabeled or improperly marked lithium ion battery in any form, the authorities will confiscate the battery. I saw a disposal bin past the security check point at Beijing Airport that was full of confiscated battery packs.

Why are the authorities so seriously concerned about the safety of lithium ion batteries? I am not suggesting that all lithium ion batteries are unsafe but under some conditions, from both perspectives of battery design and battery operation, a lithium ion battery can become a fire hazard. That's the topic of today's blog.

1. Can the design of the lithium ion battery make it inherently unsafe?

Absolutely! There are countless stories of battery factories that have caught fire in the past decades. The fundamental reason is that lithium metal (not as ions, but as lithium metal in the form of Li2) is highly flammable in the presence of oxygen or water vapor, both abundantly present in air. Therefore, it comes down to assessing whether the design of the battery can allow the formation of lithium metal inside the battery. Unfortunately, as energy density increases, battery manufacturers are forced to pack more material into the electrodes and compress the battery into smaller volumes. One of  unintended consequences of this trend is increased risk of lithium plating. 

For readers who are technically inclined, lithium plating occurs when the voltage of the carbon anode relative to a fictitious lithium reference electrode approaches zero. I explained in an earlier blog the potential contribution of each electrode. Let's re-examine this graph once more. The voltage of the anode is shown in red. Lithium plating happens to the right side of the chart when the graphite is getting filled with lithium ions. Inherently robust designs adjust the geometry of the cathode relative to the anode so that full battery capacity never coincides with an x = 1.0. In other words, the battery is full of charge (i.e., 100% of charge) but the graphite anode is actually at x < 1.0, thereby ensuring that the lithium plating threshold is never reached. The trick, from a battery design standpoint, is to also not sacrifice energy density. This dilemma, avoiding lithium plating vs. increasing energy density, is where battery designs tend to trip and become sensitive to lithium plating.

2. Can one operate the battery unsafely and cause the battery to catch fire?

Absolutely! Even a well-designed battery, in other words, one that is designed to be safe within some given parameters, can be operated in an unsafe manner. Three examples of bad operation come to mind:

i) Charging the battery to voltages above its rated maximum, often 4.35 V: When this happens, the cathode voltage increases above 4.35V and the anode voltage drops below zero, thereby causing lithium plating.

ii) Charging at high charge rates using CCCV or some derivative of CCCV: The high charging current, if not applied properly with the right control algorithms, can also cause the anode voltage to dip below zero and result in lithium plating.

iii) Charging at low temperatures: As the battery temperature drops below 10 °C, the electrolyte becomes viscous, think of gummed up, and consequently, the ions have difficulty in making their journey from the cathode to the anode. This also creates the conditions necessary for lithium plating. 

Fortunately, modern battery protection systems are there to ensure that these unsafe operations are not allowed -- that is if they are well-designed; hence I suspect the origin of the caution by the Chinese airport authorities.

Lastly, one might ask: If the lithium plating happens inside the sealed battery and is never exposed to air, why is it a hazard? The answer is quite simple. Lithium metal plating will grow in time as the battery is used. Once this metal deposit or dendrite grows sufficiently long, it will form an electrical short between the anode and the cathode....and boom, catastrophic failure ensues.

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

42.  WHY STEP CHARGING IS MISLEADING                                              

You are now asking, what is "step charging?" The standard charging methodology for lithium ion batteries has been something called CCCV, which stands for constant-current-constant-voltage. As the name implies, the charging starts with a phase of constant charging current into the battery, until the battery terminal voltage reaches 4.35 V, at which point the charging circuitry switch to maintaining a constant voltage at the battery terminals. This ensures that no excessive and unsafe voltages are applied. As I indicated in an earlier blog, CCCV has proven to be a major source of headaches for the battery. Over the past 20 years, a variation on CCCV called step charging, continues to come in and out of consideration.  The figure below illustrates how step charging introduces an additional charging step where the constant current value is reduced so that the charging is gentle on the battery.

But step charging is very misleading and does not solve the problem in fast charging. Instead, it forces the manufacturers to create more compromises that are covered up with marketing gimmicks. Here are a couple of reasons.

1. IT REALLY IS NOT FAST CHARGING:

 Step charging includes an initial phase of increased charging current, then drops into a second phase of much reduced charging current to be gentle on the battery. Therefore the fast charging is only limited to the first phase of charging. But this phase tends to be relatively short, typically taking the battery to only about 30 or 40% of charge. The overall charge time for the battery remains very long.  In other words, once the battery reaches 30 or 40%, the charge time slows down and your anxiety takes off. In fact, the overall charge time for step charging ends up being worse than that of CCCV. And users notice this very quickly. Browsing the comment sections on the Moto X (one of very few phones that use step charging) illustrate how users notice that the fast charging is really limited. Considering that very few consumers will wait to charge when the battery is below 20%, the benefit of step charging becomes very small.

2. CHARGE TIME GETS WORSE WITH USE:

One of the hidden secrets of step charging is that its charge time grows with battery age. If we look in greater detail at the current profile of step charging in the figure above, the duration of "fast charging" is directly related to the duration of the first constant current phase, i.e., when the charging current is high. The onset of the "step" is when the current drops in value, at which point the charging really slows down. Well, the hidden secret is that as the battery ages, the onset of this step moves to the left. In other words, the duration of the fast charging phase shrinks as the battery ages. So instead of reaching 40%, now this step happens near 20%. So it is a double whammy: as the battery ages and its amount of charge dwindles, and the user loses battery life, it now takes far longer to charge the battery. How much longer? The figure below shows after 500 cycles, the charge time from 0 to 50% of the battery, CCCV and Qnovo charging is about 32 minutes, whereas step charging has grown to 50 minutes! This is not acceptable!

So how can you tell whether your mobile device is using step charging. For now, the only devices on the North American market that are using step charging are made by Motorola. In particular, the Moto X makes an additional and very serious compromise: it reduces the capacity of the battery in order to use step charging. The Moto X has a battery capacity of 2,300 mAh, greatly insufficient for a full day of use, especially for this 5.2-in giant.  In other words, step charging creates more reasons for more compromising. This is not innovation!

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

41. LCO, LFP, NMC...CRYPTIC LIVES OF THE CATHODE                              

What flavors does the lithium ion battery come with? The answer is: quite a few. They represent the various combinations of materials that are used for the two electrodes, the anode and the cathode.

It turns out the available choices for the anode are quite limited. Different forms of carbon, in particular graphite, are the common choice in all commercial applications. Silicon and silicon-carbon composites as well as tin are candidates for future anode materials but they are not presently in wide commercial use.

But the cathode has enjoyed a longer list of candidate materials, typically known by their acronyms.  All of these materials are lithium metal composite alloys, with many them using heavy metals such as cobalt and nickel.Each material seems to fit a particular application. Lithium-cobalt-oxide (LCO) is most commonly used in applications where high energy density and high capacity are needed, in particular mobile devices. Lithium-iron-phosphate (LFP) is of particular interest to the automotive industry especially in China. Its safety, long cycle life and low cost make it attractive to electric vehicles. Nickel and manganese composites have been rather limited in their utilization primarily due to cost considerations. For example, the Tesla Model S uses 18650 cells made by Panasonic with nickel-cobalt-aluminum (NCA) alloy for the cathode material.

Another salient difference between these materials is their open circuit voltage; in other words, how their terminal voltage varies with the amount of charge stored in the cell (the state of charge or SOC). The graph below shows that dependence during charging. As more charge is added to the battery, its terminal voltage rises.

One will quickly notice that LFP has the lowest average voltage, near 3.2V, considerably lower than the voltage for NMC or LCO, both hovering near 3.7V. In fact, modern cells made with LCO have a maximum voltage of 4.35V, up from 4.2V, thus raising the average voltage to 3.8V. This higher voltage, and consequently higher energy, makes LCO an attractive material for use in mobile devices.

Additionally, the voltage behavior near empty (below 15% SOC) plays a big role in the utility of the material. LCO can sustain a useful voltage above 3.6V down to about 5% remaining charge, whereas NMC drops below 3.5V when the SOC is at 10%. This is yet another reason why the mobile industry continues to choose LCO.

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

40. WHAT ARE THE REAL  0% AND 100% POINTS?                                                      

Your fuel gauge indicator, whether it is in your smartphone, tablet or even electric vehicle, gives an indication of remaining charge in your battery. That indicator is universally given in percentage. It is assumed that at 100%, the battery is full, and at 0%, the battery is empty. But what is the definition of full and what is the definition of empty. That's the topic of today's post.

In an earlier post, I showed how the voltage across the terminals of an individual battery cell is really the composite voltage contributions of both electrodes, the anode as well as the cathode. The voltage contribution for each electrode varies with the fraction of lithium ions that are embedded inside the electrode. A user can only measure the composite voltage sum of the two electrodes when he or she measures the terminal voltage of the cell.

The first point to understand is the relationship between the fraction of lithium ions inside the electrode material vs. the notion of empty or full. When the graphite or carbon anode is completely devoid of lithium ions, the cell is truly empty. In other words, there are no available lithium ions and consequently, no "stored" charge. From that earlier post, one can see that the composite cell voltage can be very low, somewhere near 1V or even less. Cells never operate near that low voltage point. A truly empty battery cell has most likely incurred serious damage to its internal structure. If any of your lithium ion cells measure less than 2V, it is time to discard them. As a result, most battery cells consider a safe lowest operating voltage to be between 2.5V and 3.0V. This is the definition that one may get from the battery manufacturer. In practice, however, a smartphone will display 0% when the cell voltage is near 3.3V. This is because several electronics components, most notably the power amplifier for the radio, will not operate efficiently below 3.3V. Consequently, your mobile device shuts off at that low voltage threshold. This is the definition of zero as made by the mobile device maker. In either case, you will observe that the definition of empty is usually related to a low operating voltage threshold, and less so about being "empty."

The chart below illustrates the dependence of voltage on the amount of charge taken out of the cell during discharge. When the battery is fully charged -- to the far left of the chart -- the voltage is at its maximum. As charge is slowly removed from the cell, the voltage declines. At some point near 3.6V, it begins to drop precipitously; in other words, one needs to take out only a small amount of charge before the voltage drops rapidly. The rate at which the voltage declines depends on the choice of material. The chart below shows the voltage dependence for a battery that is made with a carbon anode and a lithium-cobalt-oxide (LCO) alloy cathode. The battery nominally stores 3,000 mAh.

If you think about this chart for a brief moment, you will quickly realize that the area under the curve is the amount of energy stored in the battery -- after all, energy is the product of charge and voltage.  So let's compare this to NiMH batteries that have a nominal cell voltage of 1.2V. Which one has a higher energy density? Naturally, lithium-ion: by at least a factor of 3X.

What about the definition of the 100% point? Is the battery full and hence cannot accept more charge? Not really. The definition of 100% is simple: the terminal voltage of the battery has reached 4.35V (sometimes, it is 4.2V but more often in consumer devices, it is 4.35V). This voltage threshold is strictly due to safety. Above 4.35V, three unsafe mechanisms begin to take place. First, lithium plating occurs in lithium ion batteries that use a carbon-based anode. These lithium metal deposits can short the cell and cause a fire. Second, the electrolyte, being liquid or gel-based, deteriorates rapidly and decomposes. The electrolyte is the medium through which the lithium ions can travel from one electrode to the other. And finally, the structure of the cathode itself begins to change its material phase and it becomes unstable. 

So there you have it, empty is really not empty, and full is really not full. Both limits are defined primarily on the basis of safety and practical utilization of the battery.

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com

39. THE BATTERY SCANDAL OF THE BOEING 787                            

The National Transportation Safety Board (NTSB) released today its incident report on the battery fire that led to the grounding of the Boeing 787 fleet for many months. It is a thorough report, nearly 100 pages long, that examines in great detail all aspects of the lithium ion battery and its systems. The result is shared responsibilities for the battery fire, with blame targeting GS Yuasa, the Japanese manufacturer of the lithium ion individual battery cells, and Thales, the French system integrator responsible for the power conversion subsystem, as well as Boeing. Even the FAA shared some of the blame in how it managed the certification process.

The report reserved special blame on the poor design, test and manufacturing practices at GS Yuasa. In essence, the NTSB reports that defects in the assembly and manufacturing of the cells led to internal shorts in the battery. Inadequate testing during certification throughout the chain did not catch these problems. Specifically, these defects led to shorts and consequently thermal runaway in cells 5 and 6. The battery contained a stack of 8 cells connected in series for a nominal voltage of 29.6 Volts.  CT scans and disassembly of defective batteries showed the failure points -- defects in the form of protrusions or wrinkling in the cathode-separator-anode winding that effectively created minute electric shorts between the cell's terminals.

The first figure below shows a schematic from the NTSB report of the design of an individual cell. It consists of a sandwich of the lithium cobalt oxide (LCO) cathode layer, the separator layer, and the carbon anode layer. Aluminum and copper foils act as the electrical conducting planes for each of the cathode and anode, respectively. This material construction is nearly identical to the ones used in the consumer industry. These layers are then folded together to form the cell windings.

The next photograph shows how the cell windings are flattened before insertion into the metal packaging can. The NTSB pointed to this winding formation and flattening process as one of the culprits in the origination of the defects and shorts. This manufacturing process created wrinklings; this is a highly technical term referring to the buckling of the electrode foils, thus compromising their integrity right during the cell manufacturing steps. Additionally, the NTSB found that the electrolyte filling process was inconsistent with the practices used in the industry and possibly led to the incomplete formation of the SEI layer (it is a thin layer that forms between the anode and the electrolyte). In other words, the NTSB pointed a clear finger at the poor cell manufacturing at GS Yuasa.

So why weren't these defects caught during the test and certification phases? Well, apparently the battery that made it on the actual B787 airplanes was different in design and properties from the batteries that underwent the tests. It seems that lots of heads at GS Yuasa and up the food chain to Boeing will be rolling -- if they have not already. Shame on the engineers and the managers who supervised and led this process.

© Qnovo, Inc. 2014 / @QNOVOcorp @nadimmaluf #QNOVOCorp    http://www.qnovo.com