The Plastic Protecting the First UL-Approved Lithium Autoclavable Surgical Battery
ConMed Corp., a leading global supplier of arthroscopic devices, multi-specialty endoscopic medical video systems, and powered surgical instruments, faced several stiff challenges when it embarked on the development of the industry’s first UL-approved lithium autoclavable battery. Previous nickel-cadmium systems for battery-operated medical devices were more costly and could only survive three minutes in the autoclave. Moreover, as hospitals raised their autoclave requirements, there was growing market demand for battery systems that could handle up to 18 minutes of sterilization and 30 plus minutes of dry time.
“We set the bar higher so we could deliver a battery not with just incremental change but revolutionary impact,” said Michael Lackey, director of research and development for ConMed Corp. “Our focus was to leap frog the competition in terms of technology and materials so we could manufacture a high-performance, long-life battery.”
The recently introduced L3000LG version of the Hall Lithium Battery System, which is made of a high-performance medical-grade polymer from Solvay Specialty Polymers, represents the latest in battery technology for powered medical instruments. Its lithium-powered performance provides nearly twice the power of standard batteries¹ for uninterrupted use during demanding procedures. The novel battery system also provides significantly longer life than standard batteries¹, resulting in greater cost savings. It is also a much simpler and cost effective solution compared to previously used sterile transfer technology systems that require the battery pack to be stored in an autoclavable case. Previously, the burden was placed on the hospital facility to use a three-piece sterilization system that was inherently cumbersome because of the need to meet proper handling requirements.
The Hall Lithium Battery System is 25% lighter than standard batteries¹ and designed with environmentally acceptable materials for recyclability. The lithium battery system, which powers surgical tools for reconstructive orthopedic procedures, features a battery housing made of AvaSpire polyaryletherketone (PAEK) resin from Solvay.
The two-year development involved a cross-functional team from ConMed Corp., including personnel from engineering, operations, quality assurance, and regulatory. The medical device maker adopted unique lithium chemistry for the battery and also teamed up with leading high-performance thermoplastics supplier Solvay to identify a material that could withstand vibration, high temperature, and hundreds of steam sterilization cycles.
Lackey noted that competitive thermoplastics failed to hold up to the strong vibration, extreme temperatures, and harsh cleaning chemicals of the autoclave and some even decrease in strength. The battery has the ability to be autoclaved with other instruments in a single tray, unlike standard nickel-cadmium batteries¹. AvaSpire PAEK is used to injection mold the black rectangular enclosures, which measure 3.5-in. (8.9 cm) high, 3.25-in. (8.25 cm) long, and 2.5-in. (6.35 cm) wide. AvaSpire PAEK is capable of withstanding an autoclave temperature of 134°C (275°F) and is chemically compatible with aggressive hospital disinfectants and cleansers. Solvay’s 30% glass-filled grade of AvaSpire PAEK provides high strength, ductility, and impact resistance, along with a UL 94 V0 flammability rating at 0.8 mm.
“While AvaSpire PAEK provides high performance in this innovative new battery system, it is the product’s unique combination of properties that sets it apart from competitive materials,” said Mike DeCesare, R&D engineer for ConMed Corp.
The battery pack consists of a lever and two enclosures made of AvaSpire PAEK that are welded together. A key part of the development project focused on the welding technology and the ability to complete a hermetic seal. The battery pack has undergone three years of accelerated end-use testing with no degradation. The battery charger takes just 30 min. to charge without the need to discharge first. The charge indicator displays charging progress to indicate battery readiness at a glance. Meanwhile, advanced diagnostics show temperature exposure and cycle count to help manage battery use. A wall mount option saves space and a wraparound cord reduces clutter.
ConMed Corp. expects to use AvaSpire PAEK in similar lithium battery designs, including the L3000SM model that is scheduled to be launched early next year.
AvaSpire is a versatile family of polyaryletherketone (PAEK) resins that provide new and unique combinations of performance and value. The AV-600 Series delivers a range of distinctive performance attributes with some grades offering more attractive economics when compared to PEEK. The AV-700 Series offers comparable performance to PEEK at up to a 30% lower cost.
¹ Compared to Linvatec’s Standard Large Nicad Battery PRO3011