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
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.
Quallion also reached a milestone in producing its 100,000th implantable lithium ion cell. The same 200mAh cell used in the storage tests has been in production at Quallion for over 10 years, and it has never had a safety event or recall. Used to power neurostimulation devices for pain management and other medical devices, Quallion’s implantable lithium ion batteries have helped tens of thousands of patients to lead healthier and more productive lives.
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.