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Sunday, 10 September 2017

Smartphone Batteries Round-up: Technology, Charging & Recycling

Back in 2013, I spoke about Smart Batteries. Still waiting for someone to deliver on that. In the meantime I noticed that you can use an Android phone to charge another phone, via cable though. See the pic below:


You are probably all aware of the Samsung Galaxy Note 7 catching fires. In case you are interested in knowing the reasons, Guardian has a good summary here. You can also see the pic below that summarises the issue.


Lithium-ion batteries have always been criticized for its abilities to catch fire (see here and here) but researchers have been working on ways to reduce the risk of fire. There are some promising developments.


The electrochemical masterminds at Stanford University have created a lithium-ion battery with built-in flame suppression. When the battery reaches a critical temperature (160 degrees Celsius in this case), an integrated flame retardant is released, extinguishing any flames within 0.4 seconds. Importantly, the addition of an integrated flame retardant doesn't reduce the performance of the battery.

Researchers at the University of Maryland and the US Army Research Laboratory have developed a safe lithium-ion battery that uses a water-salt solution as its electrolyte. Lithium-ion batteries used in smartphones and other devices are typically non-aqueous, as they can reach higher energy levels. Aqueous lithium-ion batteries are safer as the water-based electrolytes are inflammable compared to the highly flammable organic solvents used in their non-aqueous counterparts. The scientists have created a special gel, which keeps water from reacting with graphite or lithium metal and setting off a dangerous chain reaction.


Bloomberg has a good report as to why we’re going to need more Lithium.

Starting about two years ago, fears of a lithium shortage almost tripled prices for the metal, to more than $20,000 a ton, in just 10 months. The cause was a spike in the market for electric vehicles, which were suddenly competing with laptops and smartphones for lithium ion batteries. Demand for the metal won’t slacken anytime soon—on the contrary, electric car production is expected to increase more than thirtyfold by 2030, according to Bloomberg New Energy Finance.

Even if the price of lithium soars 300 percent, battery pack costs would rise only by about 2 percent.

University of Washington researchers recently demonstrated the world's first battery-free cellphone, created with funding from the U.S. National Science Foundation (NSF) and a Google Faculty Research Award for mobile research.

The battery-free technology harvests energy from the signal received from the cellular base station (for reception) and the voice of the user (for transmission) using a technique called backscattering. Backscattering for battery-free operation is best known for its use in radio frequency identification (RFID) tags, typically utilized for applications such as locating products in a warehouse and keeping track of high-value equipment. An RFID base station (called a reader) "pings" the tag with an RF pulse, which allows the tag to harvest microwatts of energy from it—enough to return a backscattered RF signal modulated with the identity of the item.



Unfortunately, harvesting generates very little energy; so little, that you really need a new standard. For instance, Wi-Fi signals transmit continuously, but harvesting that energy constantly will only enable transmissions of about 10 feet today. Range will be the big challenge for making this technology successful.

So we wont be seeing them anytime soon unfortunately.

Recycling of materials is always a concern, especially now that the use of Lithium-ion is increasing. Financial Times (FT) recently did a good summary of all the companies trying to recycle Lithium, Cobalt, etc.

Mr Kochhar estimates over 11m tonnes of spent lithium-ion batteries will be discarded by 2030. The company is looking to process 5,000 tonnes a year to start with and eventually 250,000 tonnes — a similar amount to a processing plant for mined lithium, he said.

The battery industry currently uses 42 percent of global cobalt production, a critical metal for Lithium-ion cells. The remaining 58 percent is used in diverse industrial and military applications (super alloys, catalysts, magnets, pigments…) that rely exclusively on the material.

According to Wikipedia, The purpose of the Cobalt (Co) within the LIBs is to act as a sort of bridge for the lithium ions to travel on between the cathode (positive end of the battery) and the anode (the negative end). During the charging of the battery, the cobalt is oxidized from Coᶾ⁺ to Co⁴⁺. This means that the transition metal, cobalt, has lost an electron. During the discharge of the battery the cobalt is reduced from Co⁴⁺ to Coᶾ⁺. Reduction is the opposite of oxidation. It is the gaining of an electron and decreases the overall oxidation state of the compound. Oxidation and reduction reactions are usually coupled together in a series of reactions known as red-ox (reduction-oxidation) reactions. This chemistry was utilized by Sony in 1990 to produce lithium ion cells.

From Treehugger: An excellent investigative piece by the Washington Post called “The cobalt pipeline: From dangerous tunnels in Congo to consumers’ mobile tech” explores the source of this valuable mineral that everyone relies on, yet knows little about.
“Lithium-ion batteries were supposed to be different from the dirty, toxic technologies of the past. Lighter and packing more energy than conventional lead-acid batteries, these cobalt-rich batteries are seen as ‘green.’ They are essential to plans for one day moving beyond smog-belching gasoline engines. Already these batteries have defined the world’s tech devices.
“Smartphones would not fit in pockets without them. Laptops would not fit on laps. Electric vehicles would be impractical. In many ways, the current Silicon Valley gold rush — from mobile devices to driverless cars — is built on the power of lithium-ion batteries.”
What The Post found is an industry that’s heavily reliant on ‘artisanal miners’ or creuseurs, as they’re called in French. These men do not work for industrial mining firms, but rather dig independently, anywhere they may find minerals, under roads and railways, in backyards, sometimes under their own homes. It is dangerous work that often results in injury, collapsed tunnels, and fires. The miners earn between $2 and $3 per day by selling their haul at a local minerals market.

There is a big potential for reducing waste and improving lives, hopefully we will see some developments on this front soon.

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