Tag Archives: Lithium ion

Researchers Developed Low Cost Battery From Graphite Waste

Lithium-ion batteries are flammable and the price of the raw material is increasing. Scientists and engineers have been trying to find out a safe yet efficient alternative to the Lithium-ion technology. The researchers of Empa and ETH Zürich have discovered promising approaches as to how we might produce powerful batteries out of waste graphite and scrap metal.

Kostiantyn Kravchyk and Maksym Kovalenko, the two chief researchers of the Empa’s Laboratory for Thin Films and Photovoltaics, led the research group. Their ambitious goal is to make a battery out of the most common elements in the Earth’s crust – such as graphite or aluminum. These metals offer a high degree of safety, even if the anode is made of pure metal. This also enables the assembly of the batteries in a very simple and inexpensive way.

In typical lithium-ion battery design, the negative electrode or anode is made from graphite. This new design, however, uses graphite as the positive electrode or cathode. In order to make such batteries run, the liquid electrolyte needs to consist of special ions that form a kind of melt and do not crystallize at room temperature. The metal ions move back and forth between the cathode and the anode in this “cold melt”, encased in a thick covering of chloride ions.

Alternatively, large but lightweight and metal-free organic anions could be used. But, this raises some questions which cannot be solved easily – where are these “large” ions supposed to go when the battery is charged? What could be a suited cathode material? In comparison, the cathode of the lithium-ion battery is made of a metal oxide which can easily absorb the small lithium cations during charging. This does not work for such large organic ions.

To solve the problem, Kovalenko’s team came up with a unique and tricky solution: the researchers turned the principle of the lithium-ion battery upside down. In Kovalenko’s battery, the graphite is used as a cathode; i.e., the positive pole. The thick anions are deposited in the intermediate spaces in the graphite. While searching for the “right” graphite, they found that waste graphite produced in steel production (known as kish graphite) works the best as a cathode material. Natural graphite is suitable when it is in the form of coarse flakes and not too finely ground.

LC709501F – Li-ion, intelligent charge controller for next-generation power banks

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by Graham Prophet @ edn-europe.com:

ON Semiconductor has introduced a highly integrated single chip power bank charge controller for the development of next generation Li-Ion powered products. The LC709501F provides broad power and voltage/current output range of 5V, 9V and 12V operation, with a maximum charge/discharge capability of up to 30W through FET selection.

LC709501F – Li-ion, intelligent charge controller for next-generation power banks – [Link]

Printable battery paves the way for custom-shape power sources

A new type of batteries called “Printable Solid-State (PRISS) Lithium-Ion Batteries” was designed by a group of researchers from the Ulsan National Institute of Science and Technology (UNIST, South Korea). The new battery is created from consecutive layers of printed composite materials.

Representation of the PRISS Battery production process
Representation of the PRISS Battery production process

With a simple stencil printing process followed by ultraviolet cross-linking, a solid-state composite electrolyte (SCE) layer and SCE matrix-embedded electrodes are consecutively printed on arbitrary objects of complex geometries, eventually leading to fully integrated PRISS batteries. Then the rheological properties of SCE paste and electrode slurry adjusted to get thixotropic fluid characteristics, along with well-designed core elements.

This technology yields many positive features, it eliminates the need for conventional microporous separator membranes and the extra processing steps of solvent drying and liquid-electrolyte injection.

With this new type of batteries, unlimited forms and sizes of batteries will be available for our various projects.

Source: Elektormagazine

Using A Bench Power Supply To Charge Lithium Ion Batteries

David Jones has another useful video tutorial about how to safely charge Lithium Ion and Lithium Polymer batteries with a bench power supply. The purpose of this tutorial is to learn how to use your lab power supply to charge your Lithium Ion battery when you don’t have a special charger circuit to do so.

NCR18650BBattery

He used NCR18650B in his tutorial, a 3.6V 3400mAh Lithium Ion battery from Panasonic.
David warned us that charging this type of battery is quite dangerous if we didn’t do it in the correct way. Even with the presence of protection circuit in Lithium Ion battery.

LiionProtec

You can find the charging diagram in NCR18650B battery datasheet.

NCR18650BChargingdiag

According to the datasheet, the charging current is 1625mA and the charging voltage is 4.2V. Charging consists of two stages, first one is the constant current stage where you must supply a 1625mA constant current and when the battery voltage reaches 4.20V, the second stage starts, which is the constant voltage stage. In this stage, the current will naturally drop down, and the cutoff is typically about 10% of charging current so it’s about 170mA.
This tutorial applies to all Lithium Ion and Lithium Polymer batteries not only NCR18650B.

LiIonBatteries

You can perform this 2-stage charging using your power supply, but it must supports CC(Constant Current) and CV(Constant Voltage) modes. You can read the following Q&A in electronics.stackexchange to learn what constant current and voltage modes mean. You can build a power supply with CC and CV modes for yourself if you don’t have a budget to buy a ready made one.

David’s Power Supply Setting With 4.2V CV and 1700mA CC
David’s Power Supply Setting With 4.2V CV and 1700mA CC
The Battery Charges in The First CC Stage Sinking 1698mA
The Battery Charges in The First CC Stage Sinking 1698mA

David said that using this type of float charging/trickle charging is not recommended, because it will build-up or plate the metallic parts inside the battery. So It’s better to use dedicated ICs designed for the float charging.

David mentioned in his video that a complete tutorial is available for whom who want to know in details how to charge lithium ion battery.

 

Lithium-Ion Battery Warms Up, Operates In Subzero Temperatures

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Charles Q. Choi @ spectrum.ieee.org discuss about a new type of li-ion battery able to work in low temperatures.

A new “all-climate” lithium-ion battery can rapidly heat itself to overcome freezing temperatures with little sacrifice in energy storage capacity and power, researchers say.

This advance might enable applications for which high-performance batteries are needed in extremely cold temperatures, such as electric cars in cold climates, high-altitude drones, and space exploration. EC Power is now creating all-climate battery cells in pilot-production volumes that can be put directly in vehicles, says study lead author Chao-Yang Wang, a mechanical and electrochemical engineer at Pennsylvania State University.

Lithium-Ion Battery Warms Up, Operates In Subzero Temperatures – [Link]