By Kyle Proffitt
July 10, 2019 | As the world market is flooded with higher-density, cheaper batteries powering your phone, laptop, car, even your child’s electric hoverboard, concerns abound. How can we maximize battery life? How can we charge faster? But perhaps the greatest concern is safety; how can we eliminate the infamous accounts of exploding batteries? Rachid Yazami, battery pioneer and inventor of the graphite anode, believes he has the best solution to this problem and wants to see his technology incorporated into every battery on the planet. As a bonus, he says he can increase the life of your battery and charge it faster too.
Yazami recently spoke at the International Battery Seminar in Fort Lauderdale, Fla. He has a vision of improving the entire landscape of battery life, from inception to inevitable death, even hoping to improve the recycling of batteries.
Yazami believes we are reaching a plateau of battery improvements: “We cannot improve constantly the energy density, as we’ve seen for the last 20 years or so. We need to use the existing technology today and do the best that we can do. The most important [improvement] for me is safety,” he told Battery Power Online.
Safety is a major concern because so many batteries are made and in use. Yazami estimates: “in 2018 close to 8 billion cells worldwide, 90% produced in China, Japan, and Korea.” He goes on to say that “some of these companies don’t care much about quality and safety.” The safety issue is primarily related to a thermal runaway event, which can start as a small short circuit between cathode and anode that increases the local temperature, melts the separator, and initiates additional reactions that further elevate temperature and result in catastrophic, flaming failure.
“The problem is, if you go ask any battery expert: ‘Is there any way to detect at an early stage a short circuit in the battery?’ they will tell you we have no clue,” Yazami says. He continues, “If we have an internal short, and that short has a current below one microamp…there is no way to measure an internal leak of that level, because you cannot see a big change in the voltage.” However, Yazami says, “I think we have at least one solution today, where we are measuring the thermodynamics of the battery—entropy and enthalpy. From that data, if you have an internal short, you can see it at a very early stage; a < 1 microamp leak can be measured.”
To measure the thermodynamics of batteries, Yazami has an elegant and simple solution—an integrated circuit, much like those already incorporated into battery packs, that carefully measures temperature, voltage, and current. “The chip that we have developed, attached to the battery, measures the entropy and enthalpy of the battery. If you do the derivative of voltage vs. temperature, you have entropy. This is textbook.” Enthalpy is calculated by a similar equation. The chip is licensed out of Singapore by Yazami’s startup, KVI PTE LTD.
Thermodynamics Tell All
It turns out performing this calculation has many additional benefits. The thermodynamic profiles are specific for each battery chemistry, and they change as the battery ages. This means that the current health of a battery can be known. Now, when a passenger boards an airplane carrying his laptop computer, there is no way to predict the likelihood that this will be the rare battery that experiences failure mid-flight. The airline cannot assess battery health. But Yazami’s chips can.
Of less incendiary importance, the thermodynamics can also tell you precisely how long you can go before finding a power outlet. Having accurate battery energy readings is crucial, “especially if you are driving a car. You don’t want to have the state of charge, the mileage that you can drive, incorrectly calculated by a computer, and then it says ‘oh, sorry, you have 2 or 3 miles left. You cannot go back home’,” Yazami says. Currently, state of charge is calculated by a computer through coulometry, but as Yazami says, “Everyone knows the state of charge reading is totally wrong.” Luckily, it turns out that “there is only one entropy and one enthalpy for each state of charge…There is a linear arithmetic function between state of charge (SOC), entropy, and enthalpy.” A simple equation defines this relationship, with variables that depend on the battery chemistry and state of health. All can be determined with this simple chip. Natural temperature fluctuations of less than one degree are sufficient to generate the profiles.
Yazami would like to see battery companies integrate his chips into their battery designs.
“I don’t think this will be a hard sell to use our IC (integrated circuit) rather than the IC they are using.” “The chip we are using now can be only 2 mm x 2 mm in size.” Yazami foresees the need for safety dictating new regulations. As an example, he says, “For the aviation industry, if they know that there is a technology that enables people to detect a short circuit in a battery, and it has proven enhancement of battery safety, I think this will become mandatory, like seat belts in cars.”
Keeping Batteries Happy
Additional benefits of these measurements come with changing the way batteries are charged. At present, chargers deliver current to batteries with little regard of age or health. Yazami has developed new methods of charging that incorporate real-time battery information. In addition to the IC for the battery pack, Yazami says, “There is another chip which is actually going inside the battery charger. As soon as you connect a battery to the charger, the two chips will communicate. The charger knows exactly the initial state of charge, which is basic knowledge. You have to know battery percentage accurately. Chip #1 communicates state of health to the charger. The charger will apply a protocol according to the initial state of charge and the state of health of the battery.”
Yazami also says he can charge cells faster. “We have developed protocols like the cascade charge. The shortest time we have achieved for fully charging is 9.5 minutes. It’s possible to charge a battery in less than 10 minutes using some of our protocols.” However, Yazami believes this fast charging should not be used regularly. Instead, a protocol called non-linear voltammetry will, “let the battery respond naturally to an increase in voltage. We increase the voltage and leave the battery to take the energy that it can take at any time.”
In the long run, your battery will thank you. “We show that when you use NLV for the charging, slow charging, you can extend the life by 2x or 3x.” Yazami says “we can get more than 1300 cycles without losing much of the initial capacity—between 5-8% of the original capacity.”
Calling All Investors
Despite having worked on this technology for over a decade, it has not been licensed by any battery manufacturers. Yazami says, “we are in the process of fundraising, and hopefully next month we will have investors coming with a big check.
