Technology

Technology

Lithium Phosphate Battery TechnologyThe processes and materials used in developing lithium iron magnesium phosphate (LiFeMgPO4) as the core of Valence U Charge® technology make for a technologically advanced, intrinsically safe cathode material for lithium powered applications in the market today.

Because this material has a high resistance to the liberation of oxygen, no significant exothermic event occurs upon heating. The redox voltage is low enough that no electrolyte decomposition occurs, thereby affording long cell life.

Valence Cathode Materials are prepared using a unique and versatile preparative method called Carbothermal Reduction (CTR), a process to develop lithium iron magnesium phosphate cathode powder in a very efficient, cost effective, stable and scalable way.

CTR makes Valence lithium iron magnesium phosphate powder longer-lasting, with more sustained conductivity, enhanced performance and ultimately a better cathode material that is more easily manufactured into cells.

CTR also enables Valence to efficiently convert Fe3+ into Fe2+ which can then be used in Valence Lithium Iron Magnesium Phosphate cathode powder. It uses carbon oxidation reactions to reduce iron oxides to a lower oxidation state. When carbon is used to reduce the iron oxide, a bond is formed between the remaining carbon and the iron. The stronger this bond, the greater the conductivity and overall performance of the cathode powder in any energy storage solution.

Testing has verified lithium iron magnesium phosphate technology (LiFeMgPO4) as one of the most inherently safe type of lithium batteries available.

LiFeMgPO4 cells under puncture or short circuit conditions are much less likely to experience thermal runaway than (for example) Lithium metal oxide. The Exponent testing report, which compares selected lithium-ion battery chemistries, is available here.



Punctured or short circuited lithium metal oxide cells will cause heating, making the oxygen bonds prone to breaking resulting in the release of oxygen and thermal runaway. This causes a fire with temperatures reaching up to 1000 degrees and self perpetuated by released oxygen from within the metal oxide cathode materials. 

With lithium metal oxide cells the bond with oxygen is much weaker than the oxygen bond with phosphorous in a phosphate permitting thermal runaway at much lower temperatures.

In terms of cycling performance Valence lithium iron magnesium phosphate cathode materials display excellent characteristics. Current cycling demonstrates minimal linear fade reaching over two thousand eight hundred full one hundred percent charge and discharge cycles to eighty percent depth of discharge.

 

Valence Technology currently use cylindrical steel case cells for all U Charge® technology products.

Cells are manufactured to exacting standards and to standard dimensions: 18650 (18mm diameter, 65mm long) In fully charged cells, no lithium is left in the cathode compared to Lithium Cobalt Oxide (LiCoO2) where 50% still remains, thereby maximizing use of available lithium.