Zero Volt Batteries and SaFE-LYTE Batteries

Performance Enhancements

Thanks to an unmatched expertise in lithium ion chemistry, Quallion has built an intellectual portfolio of patented technologies that give our batteries—and thus our customers—a competitive advantage. These enabling enhancements give our Li-ion batteries unrivaled safety and performance.

Calendar Fade/Self Discharge
Long life chemistry
Wide Operating Temp

Calendar Fade/Self Discharge
Two critical performance criteria for Li-ion cells are calendar fade and self discharge.  Quallion’s 5A2 chemistry has demonstrated unrivaled performance in both circumstances.

Aerospace: Quallion’s 15 Ahr LEO and GEO satellite cells have demonstrated 95% calendar life retention capacity after 500 days at room temperature storage. Notably, these cells were charged to 4.1V each time they were returned to storage.

Medical: After 10 years of storage at an elevated temperature mimicking conditions inside the human body, Quallion cells showed minimal degradation in terms of calendar fade and self discharge.

In 2003, Quallion placed 15 fully charged (4.1V) 200mAh implantable lithium ion cells into storage at a controlled temperature of 37OC.  Quallion performed testing on 6 of the cells after 4 years and most recently tested another 2 cells after 10 years in storage.  The most recent results show less than 7% calendar fade (irreversible loss of storage capacity over time) and less than 18% self discharge (loss of stored energy which could be recovered by a subsequent charge cycle).  Quallion will keep the remaining 7 cells in controlled storage for testing in future years.

Calendar fade and self discharge are unavoidable processes in a lithium ion cell that occur as the cell’s anode and cathode materials degrade over time.  These processes are exacerbated by elevated temperatures, such as the 37OC condition inside the human body, and by a high state of charge, as found in a fully charged cell.  Quallion’s tests confirm the long life of the cell even under these stressful conditions.  Coupled with proprietary Zero-VoltTM capability to withstand deep discharges and unrivaled cycle life, these data further bolster Quallion’s industry leading lithium ion cell chemistry. 

The long life of Quallion’s batteries can help extend the useful life of implantable medical devices, improving patient outcomes and reducing healthcare system costs.  By avoiding additional surgeries to replace batteries, Quallion’s technology reduces patient risks and hospital admissions.
The operational life of a Li ion battery is determined by its cycle life, self discharge and calendar life performance. Quallion's chemistry, a LiNiCoAlO2 cathode and graphite anode have demonstrated over 30,000 DOD cycles at depths as deep as 60% DOD . Quallion’s patented long life chemistry optimizes this positive/negative chemsry to achieve an effective balance between cycle life and energy density. To date, Quallion’s cycle life performance has been demonstrated in various types of test and production cells that include a variety of shapes and case materials.

Quallion’s patented Zero Volt™ technology allows long storage periods in a deep discharged state with no permanent capacity loss due to low voltage. The ability to discharge a battery to zero volts offers a number of important advantages in many medical, space, and military applications. Most importantly, it means that batteries can be stored for long periods of time without maintenance. In addition, the charge can be completely removed when connecting batteries to volatile systems or implanting cells inside the human body. In all applications, batteries are guaranteed to function at peak capacity levels, even after long storage periods without any maintenance. This benefit is particularly valuable in some military and satellite applications, where even infrequent maintenance is not possible in some situations, and obviously offers advantages over conventional Li-ion batteries that cannot survive a deep discharge.
. With our proprietary SaFE-LYTE technology, Quallion has successfully found a way to enhance battery safety without any compromise in electrochemical performance. It is well known that lithium ion batteries are intrinsically less safe than other battery chemistries such as Ni-MH and lead acid, because Li-ion batteries contain a flammable non-aqueous electrolyte. For that reason, piercing and compression may cause a battery to ignite and catch fire. In recent years, hundreds of catastrophic cell phone battery failures have occurred. Concerns about this problem—and calls for innovative solutions—have grown as the energy densities and cell capacities in these batteries have increased. Quallion’s SaFE-LYTE technology integrates into the battery a liquid halogen compound that is flame-retardant and immiscible in the electrolyte. This solution significantly lowers the risk of combustion, and allows Quallion to produce batteries that are far safer than conventional Li-ion options.
.A major contribution to the deterioration of discharge performance at low temperature is the high percentage (30–50%) of ethylene carbonate (EC) used electrolyte solutions. With its high melting point (36.4°C), EC is primarily to blame for the poor power capabilities observed at low temperatures. However, the use of EC is necessary for formation of the solid electrolyte interface (SEI) on the anode electrode, which has been shown to contribute to the long life characteristics of lithium-ion cells. To combat this problem, Quallion has evaluated alternative co-solvents to improve low temperature performance. For example, one Li-ion chemistry developed at Quallion shows excellent capabilities at lower temperatures, showing >75% capacity when discharged at a .5C rate at -40°C to 2.0V.