Invention: Battery electrodes, batteries for implantable defibrillators
Millions of heart patients with implantable cardiac defibrillators (ICDs) have benefited from the battery technologies pioneered by US materials scientist and chemical engineer Esther Sans Takeuchi. Her lithium/silver vanadium oxide (Li/SVO) batteries paved the way for smaller ICDs with significantly longer battery life, resulting in less surgery for ICD replacements.
Before Takeuchi's invention, ICDs were overly large devices
with a battery life of 12 to 18 months at best. The first ICD, implanted
in 1980, was placed into the patient's abdominal region due to its size; today, they are fitted underneath the collarbone
in the same location as pacemakers.
Because ICD replacement requires major surgery, and takes place every time the batteries are about to expire, the quest for better and smaller devices was primarily a search for better batteries. The main challenge: ICDs "shock" the heart back to normal function and require an electrical current of around two to three amperes to charge their capacitor. This charge is over one million times greater than the electric current powering cardiac pacemakers, typically about only 10 microamperes.
Enter Esther Sans Takeuchi. Perfected in the mid-1980s, her compact Li/SVO batteries, in conjunction with several key patents for the technology, resulted in the first defibrillator equipped with a powerful yet small battery that had significantly greater longevity than its predecessors.
First implanted in a patient in 1987 and commercialised by medical device manufacturer Greatbatch Inc., Takeuchi's patented principle is the most commonly found technology in ICD batteries today and offers battery life of up to five years.
Societal benefit
The inventor's battery technology has powered the widespread adoption of ICDs that started in the late 1980s and continues today. About 10 000 people in the United States receive an ICD implant every month. The cost of the device is between EUR 25 000 and EUR 43 000 per patient.
ICDs are especially effective in regulating cardiac arrests due to ventricular arrhythmias. These complications cause about 7% of all heart attacks, of which ICDs have rendered them one of the more preventable causes. In the US alone, between 200 000 and 400 000 people die suddenly every year as a result of heart rhythm abnormalities. The number of adults living with heart failure rose to 6.5 million between 2011 and 2014, and the numbers are projected to rise by 46% by 2030.
Economic benefit
Takeuchi developed the Li/SVO battery with funding from technology firm Greatbatch Inc. (renamed Integer Holdings Corporation in 2016), where she worked for 22 years. Since its initial implementation in 1987, the Li/SVO system has been improved through materials synthesis, electrolyte modifications, electrolyte additives and cell design. Updates include the Q Series battery, based on two patented innovations developed by Takeuchi and released in 2005.
US-based Integer Holdings Corporation reported sales of EUR 1.2 billion in 2016, with almost 30% generated by cardiac and neuromodulation systems. Sales revenues from such devices have been increasing in recent years, with an 8% increase from 2014 to 2015, and 9% the following year.
According to Transparency Market Research, global sales in the battery market for cardiac rhythm management devices are expected to rise from EUR 338 million in 2015 to EUR 441 million by 2024. The research group identified the Asia-Pacific region as the greatest focus for growth, due to an increase in various health ailments such as hypertension and diabetes, which result in a higher prevalence of cardiovascular diseases.
