Implantable Medical Batteries
With superior energy density, reliability, and safety, Quallion’s rechargeable lithium ion and non-rechargeable Li/CFx technologies are enabling medical applications that were unthinkable in the past. Today, these long life Li-ion cells are qualified to power a wide range of devices, including cochlear implants that bring hearing to the deaf, spinal-cord stimulators that bring relief to sufferers of chronic pain, glucose sensors that enables diabetics to stabilize their blood-sugar levels, and cardiac rhythm management devices that help diseased hearts beat properly or survive until a transplant is possible.
In these and many other implantable applications, our cells can be counted on to deliver longer life, ultra-high safety, and unbeatable reliability in the challenging operating conditions within the human body. In fact, Quallion’s proprietary technology used in medical batteries has been designed to last 25 years implanted in the human body and has demonstrated over 10 years of long life since its introduction in 2003. Quallion has demonstrated longer cycle life than and lower self discharge and calendar fade than any other lithium-ion cell manufacturer on the market. Such reliability is critical in the implantable device market, since power failure in these devices is literally a matter of life and death. For added safety, our medical cells also feature Quallion’s patented Zero Volt™ technology, which allows batteries to be implanted and kept in a discharged state with no permanent capacity loss.
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.
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.
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.