Fast charging is a revolutionary invention that has changed the world. It has changed the way people use their devices. A non-intuitive problem to the average person, but let’s dive deep to this fascinating stream of technology.
Phones
The premise is simple, charging, but faster, without blowing up your phone.
A few years ago, your average smartphone would typically come with a 5W charging cable, which would usually charge your phone from 0 percent to 100 percent in about two or two and a half hours. Today, 40-65W fast charging is available on most smartphones, and some even support 80W. The OnePlus 10R & the Realme GT Neo 3 150W edition support 150W charging, which can fully recharge a 5000mAh battery in nearly 17 minutes. Now that’s impressive. So how does it happen without blowing up your phone?
Not all phones are created equal.
Now, different manufacturers use different fast-charging protocols. Apple and Google phones use USB-PD, whereas most Android phones use the latest Qualcomm standard or, as with Realme and OnePlus, their proprietary charging protocols. Most of these protocols function similarly. The difference arises in the power allowed to pass between the charging brick and the device itself. A controller chip is used to perform this function. The ports on the device are calibrated to operate only with a specific type of charger to reach their maximum capacity. A certain fast charger from OnePlus, for example, might not work on a Samsung phone.
A touch of chemistry
In any given battery, there is a positive terminal and a negatively charged terminal. Most phones use a lithium-ion or a lithium polymer battery. When a battery is powering a device, the lithium ions flow from the negative side to the positive side, through a liquid electrolyte solution. This flow is what powers the device. When there are insufficient lithium ions on the negative side, i.e., the flow becomes weak or stops altogether, the battery runs out of charge.
Charging the battery again makes the ions flow from the positive side, back to the negative side, again, through the liquid electrolyte solution. The wattage of the charger, and the charging protocols, determine the speed with which this flow takes place. The higher the wattage, the faster the flow of the ions at the peak.
Dealing with heat During the charging process, it is this electrolyte solution that heats up. Sometimes, this heating up of the solution may even cause the battery to explode, especially if it isn’t managed properly. That is why you will see that as a battery starts reaching its maximum storage while charging, say, 75 percent or so, the charging speed slows down. This is done to reduce the heat output, and extend the battery’s life. Another thing that causes the battery to heat up, is that after a certain number of charging cycles, these ions lose their capacity to hold a positive charge. This means they cannot flow through the solution. This is why, after a few months or years of usage, the capacity of the battery also dips. The more “dead” ions in a battery, the quicker it heats up. This also leads to batteries expanding. Basically, with fast charging, the wear and tear on a device’s battery are significantly higher.
Expanding batteries Now, the cells inside a lithium-ion battery will expand a small amount when it is being charged. This is because of the heat and is a completely normal process. It returns to its original form when the electrolyte solution cools down, provided it is not loaded with dead ions. To counter this and to give devices and their batteries a longer life, manufacturers have now started using split batteries. Instead of one huge battery with a capacity of, say, 5000mAh, some manufacturers are using two batteries of 2500mAh each.
Fast charging is a double-edged sword for most manufacturers and users. That is the reason why, most of the research and development around batteries now, is around managing the time taken to charge and ways to optimize battery health. With 240W fast charging on its way, it will be interesting to see how manufacturers improve ways to make batteries last longer, and how to maximize battery health.
A summary of how fast charging works - new charging structure | MTW battery technology | Mi-FC technology | Liquid Cool technology | Graphene application on Li-ion battery.
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Cars
Introduction
Petrol and diesel-engine cars have historically had one major advantage over electric vehicles: fuel efficiency. But that looks set to change with the release of a new fast-charging battery. Electric vehicles are gaining popularity fast, but some prospective buyers remain hesitant due to current day charging speeds. While drivers today are accustomed to filling their gas tank in less than five minutes, EVs, depending on the size and specifications of the battery, typically take at least 30 minutes to get 80 percent charged at the fastest charging stations out there.
A touch of science
The batteries inside today’s EVs are composed of thousands of lithium-ion cells that store and release energy thousands of times. Each of those cells consists of two electrodes—a metal cathode and a graphite anode—separated by a liquid electrolyte. While the battery is charging, lithium ions flow through the liquid from the cathode to the anode. They fill up spaces between the graphite layers like wooden blocks fitting into a Jenga tower.
The speed at which lithium ions move from the cathode into the anode dictates how quickly the battery charges. But just as placing blocks in a Jenga tower too rapidly can cause the structure to become unstable, if lithium is forced into the anode too fast, problems start to arise.
So, at high charging speeds, lithium batteries can overheat, causing them to degrade over time. More problematically, lithium can start to build up on the surface of the anode instead of entering it, a phenomenon known as lithium plating. Not only can that drastically reduce the battery’s capacity, the lithium deposits eventually form filament-like structures known as dendrites. Once they start forming, those dendrites can grow across the electrolyte, touch the cathode and create a short circuit, causing the battery to catch fire or explode. That’s not particularly encouraging from a safety point of view.
Companies are developing new lithium-ion battery materials and “solid-state” batteries, which are more stable at faster-charging speeds. They could offer recharge rates of 20 minutes or less within reach. Israeli firm StoreDot unveiled its next-generation lithium-ion car battery, which it claims can be fully recharged from empty in just five minutes, a development that could eliminate range anxiety. Said to be the main hurdle stopping more drivers from adopting electric vehicles, range anxiety is the fear of running low on power before reaching your destination. This is the fear of having to sit around for a long time waiting for the battery to charge.
Positive
Another way to make a lithium-ion battery that can safely charge even more quickly is to use alternative anode materials. For instance, a U.K.-based start-up Echion technologies have developed a niobium anode that doesn’t promote lithium plating or dendrite formation. Batteries made with this material can be charged “as fast as you want,” says CEO. His prototype EV battery cells can be powered in six minutes “without impacting the safety or life of the battery. “
However, that quick charge comes with a price: Niobium anodes store less energy per unit mass than conventional graphite ones. Because EV makers tend to prioritize energy-dense batteries (which can be driven longer on a single charge) over ultra-fast charging ones, Echion is currently targeting other markets for its batteries, like grid storage and power tools. Eventually, they envision that a version of these batteries might be used in vehicle fleets where any downtime to recharge costs the company money.
For individual drivers looking for a bigger jolt of kilowatts, emerging solid-state battery designs offer promise. In such batteries, the lithium ions flow through a solid electrolyte, often a ceramic, rather than a liquid one. Because liquid electrolytes are flammable, this makes the battery safer. It also opens up the possibility of using different anode materials that are more resistant to lithium plating and can therefore be charged faster.
Solid Power, a company that is developing solid-state batteries with funding from BMW Group and Ford, is working on a silicon anode battery cell that chief technology officer Joshua Buettner-Garrett says can be charged halfway in 15 minutes, and it’s targeting 20-minute full recharge rates for a commercial version. It’s also developing batteries with lithium metal anodes, which can store ten times more energy per unit mass than graphite. In a solid-state design, lithium metal batteries should theoretically be able to charge up very quickly. In practice, though, they too are prone to forming dendrites, causing them to fail quickly, especially at high charge speeds. Fast-charging lithium metal batteries would be the Holy Grail of high-performance EV batteries, says CEO of Solid Power.
New research may be pushing these super batteries closer to reality. Recently, a team led by Harvard University materials scientist Xin Li designed a solid-state lithium metal battery cell that uses several different layers of materials in the electrode to arrest lithium dendrite growth. In the journal Nature, the team described a prototype battery that could be charged in just three minutes. It could also retain more than 80 percent of its capacity after 10,000 cycles. (Typical EV batteries degrade by a similar amount after 1,000 to 2,000 cycles.) The team is in the process of demonstrates that the battery, currently the size of a coin, can be scaled up and mass-produced for automobiles. A commercial version of this battery may be possible in about five years “if everything goes right.” If the advantages of lithium metal can be harnessed, says Venkat Viswanathan, an engineer at Carnegie Mellon University whose lab also develops next-generation batteries, “a lot of the assumptions that you have made in terms of fast charging go out the window.”
Re-engineered lithium-ion battery could let you fill up electric cars almost as fast as those that run on fossil fuels. The recharging speed of StoreDot’s ‘extreme-fast-charging’ lithium-ion battery technology has previously been demonstrated in mobile phones, drones, and electric scooters but the company has now adapted it for use in cars.
The batteries differ in construction from conventional lithium-ion batteries in several ways, most notably by substituting graphite components for germanium. Germanium has a lower resistance than graphite, allowing faster rates of charge with less heat generation. It also reduces the gradual degradation of a lithium-ion battery – a process known as ‘plating’ – that fast charging would otherwise accelerate.
StoreDot hopes to make further improvements by switching germanium for silicon, a cheaper alternative, in its second-generation battery, prototypes of which are expected to see the light of day later in 2021.
Faster charging batteries are a welcome development, but they aren’t the only barrier to the widespread adoption of electric vehicles. Considering the switch, motorists also have concerns about the charging infrastructure.
It may take longer, however, before we see manufacturers adopt upgraded technology in their cars. A review published in the transportation journal, by Anna Tomaszewska and colleagues, suggested that longer, real-world testing would
There was needed to ensure the next-generation fast-charging batteries could perform well over long timescales. There are many variables to consider. Roughly speaking, in the UK, an electric car charged from the mains currently emits roughly 80g of CO2 per mile. This is compared to 216g CO2 per mile for the average petrol car. An electric car’s emissions depend on what proportion of its electricity is derived from burning fossil fuels. Therefore, they vary from country to country, and according to the time of day. As we generate more energy from renewable sources, the carbon emissions of electric cars will drop further.
Let’s talk about innovation in the Chargers themselves, ABB’s new Terra 360 is only charger designed explicitly to charge up to four vehicles at once. Ideal for refuelling stations, urban charging stations, retail parking, and fleet applications. ABB is today launching an innovative all-in-one Electric Vehicle (EV) charger, which provides the fastest charging experience on the market. ABB’s new Terra 360 is a modular charger that can simultaneously supply power to up to four vehicles with dynamic power distribution. This means that drivers will not have to wait if somebody else is already charging ahead of them. They simply plug into another plug. The newly developed charger has a maximum output of 360 kW and is capable of fully charging an electric car in 15 minutes or less. This meets the needs of a variety of EV users, whether they need a fast charge or to top their battery up while grocery shopping.
“It’s an exciting day for ABB, who as the global leader in electric vehicle fast charging, is playing a key role in enabling a low carbon society,” said Theodor Swedjemark, Chief Communications and Sustainability Officer at ABB. “With road transport accounting for nearly a fifth of global CO2 emissions, e-mobility is critical to achieving the Paris climate goal. We will also lead by example by switching our entire fleet of more than 10,000 vehicles to non-emitting vehicles.”
Available in Europe from the end of 2021, and in the USA, Latin America, and the Asia Pacific regions in 2022, Terra 360 is designed with the daily needs and expectations of EV drivers in mind. Leveraging the rich field experience gained by ABB E-mobility’s large installed base, the Terra 360 delivers speed and convenience along with comfort, ease of use, and a sense of familiarity.
Its innovative lighting system guides the user through the charging process and shows the State of Charge (SoC) of the EV battery and the residual time before the end of an optimal charge session. The world’s fastest EV charger is also wheelchair accessible and features an ergonomic cable management system that helps drivers plug in quickly with minimal effort. As well as serving the needs of private EV drivers at fuelling stations, convenience stores, and retail locations, Terra 360 chargers can also be installed on an organization’s commercial premises to charge electric fleet cars, vans, and trucks. This gives owners the flexibility to charge up to four vehicles overnight or to give a quick refill to their EVs during the day. Because Terra 360 chargers have a small footprint, they can be installed in small depots or parking lots where space is at a premium.
Negative
Because of the problems with fast charging, all EV batteries have built-in charging speed limits, set by the car’s onboard charge ports. A 350-kilowatt fast-charging station—the most powerful public charger available in the U.S. today—might, in theory, be able to fuel an Audi E-Tron SUV’s 95-kilowatt-hour battery in about 16 minutes. But the battery itself can only accept about 150 kilowatts of power at most, placing its actual discharge speed limit closer to 40 minutes.
Exactly how fast a battery will recharge in the real world depends not only on the charger or how many kilowatts of power the battery was designed to accept. It also depends on the battery’s size, how charged it is, and even the weather. Still, state-of-the-art fast-recharging stations can often get an EV battery 80 percent full, potentially adding hundreds of miles of range, in about 30 minutes. (Once a battery is 80 percent full, the charging speed slows down to prevent the battery from being damaged.) Tesla owners can visit a supercharging station that will add up to 200 miles of range in 15 minutes. While adding 200 miles of range in 15 minutes is fast, it’s a far cry from gassing up for a road trip in five minutes flat. Those hoping for an EV charging experience like that might want to hold out for the next generation of battery technologies.
Even if EV batteries that can charge in less than 10 minutes are technically possible, it’s not clear that ultra-fast charging will ever be practical. At 400 volts and higher, today’s fast-charging stations already draw much more power from the electric grid than the 120- and 240-volt outlets many EV owners use at home. If all Americans were driving EVs and everyone expected ever-faster charging to be available all the time, that could place some serious strain on the grid.
“The infrastructure needs to be considered as well,” Li says. “We have to see how much current the entire system can support.”
Jenny Baker, a battery storage expert at Swansea University in the U.K., isn’t sure ultra-fast charging is the right goal. Charging up at home overnight when demand is lower, she notes, is more affordable and environmentally friendly. This is because grid operators have to draw less on backup power plants, which tend to burn dirtier fuels. Many EV owners, Baker included, also find that more convenient than stopping to recharge during the day.
“Charging at home, if you have the ability, is the most efficient option for the environment,” Baker says. “I would be very disappointed if electric vehicles become just like gas cars because that won’t fulfil all of their potentials.”
Conclusion
Experts question whether EVs that can be charged so quickly are the future we want—at least with the electric grid we have now. Despite concerns about charging infrastructure, 2020 was the best year ever for sales of electric vehicles, with battery and plug-in hybrid cars accounting for 1 in 10 registrations, according to figures from the Society of Motor Manufacturers and Traders (SMMT). In 2019, that figure was 1 in 30. With all the ongoing innovation on fast-charging battery technology, it’s a bright and positive future to look forward to.
