Every healthcare facility relies on medical batteries for reliable functioning. Electronic medical devices are crucial equipment that sustains vital health functions. Therefore, understanding the basics and types of batteries used in the medical industry is of prime importance.
There are many different options when it comes to batteries for medical devices. There are also certain regulations that healthcare organisations need to meet regarding batteries in the medical industry. This article will explore all the information related to batteries in medical devices. You will also learn many tips to store, dispose of, maintain, and troubleshoot medical device batteries.
What is a Medical Battery?
A medical battery is a type of rechargeable batteries that supplies power to medical devices in a clinic or a hospital. Medical batteries provide electricity to various equipment such as X-rays, CT scans, MRIs, blood analyzers, surgical tools, lab diagnostics, and more.
Medical equipment requires constant operation without any disruption. Additionally, there is also a vast presence of portable medical devices. Therefore, relying solely on the electrical grid is not sufficient. Medical batteries solve this issue by providing consistent power even when the grid power is unavailable.
What are the Different Types of Medical Batteries?
There are many different design options in which one can use medical batteries. These different types of medical battery designs are:
A built-in battery is an integral part of the medical device. These batteries are charged from the grid connection of the medical devices. These batteries are not removed and charged separately. Generally, battery maintenance requires disassembling medical devices. These batteries are generally connected to stationary devices, such as vitals monitors and defibrillators.
A removable battery is not an integral part of medical devices. These batteries are present in a dedicated battery compartment of the equipment. The maintenance personnel or nurses can conveniently open the compartment and remove the battery to charge it. There are dedicated charging stations for this purpose. Battery maintenance is also easy since the battery can be taken out quickly. Common applications of these batteries is diabetic monitors, blood pressure monitors, and surgical tools.
A standby battery is kept as an emergency backup option for powering medical devices. The devices are generally portable in nature, such as medical equipment on wheels or in an ambulance. Standby batteries are kept in a fully-charged state as they may be required at any time without notice.
External Battery Packs
External battery packs are separate units that do not go inside the medical devices. The devices are connected to the external battery pack with connection cables when they require power. This makes the device lightweight and easy to move around. Additionally, the external battery packs can power multiple devices. These batteries are also commonly kept on medical carts.
Different Types of Battery Chemistry Used In the Healthcare Industry
There are many different options for battery chemistry in the medical industry. These different types of battery chemistry are:
Lithium Ion Batteries
A lithium-ion battery has one electrode made out of a lithium-based compound. The other electrode is made of a carbon material like graphite. These batteries store and generate power through the movement of lithium ions created by internal battery reactions. Lithium-ion batteries are the most popular battery technology used in the medical industry. In fact, lithium-based batteries have been the most applied technology for many decades.
There are many different types of lithium-ion batteries used in the healthcare sector. Let us go through these different types along with their pros and cons:
Lithium-Manganese Dioxide [LiMnO2] Battery
Lithium-Manganese Dioxide battery has lithium metal anodes and a Manganese Dioxide (MnO2) cathode. These batteries come in many shape forms, such as cylindrical, thin cells, and rectangular. LiMnO2 battery is a non-rechargeable lithium-ion battery.
- Availability of different shapes
- Low self-discharge rate (around 1% to 5% per year)
- Non-corrosive electrolyte
- Long shelf life
- High energy density
- Less cost-effective
The most common application of LiMnO2 in medical devices is for powering defibrillators such as the Philips HeartStart.
Lithium-Carbon Fluorides [Li-(CFx)] Battery
A Lithium-Carbon Fluorides battery has a lithium anode and a fluorinated carbon cathode. These batteries are also known as CFx batteries. CFx batteries are generally available in non-rechargeable options. However, the rechargeable alternative is also under research.
- Long shelf life
- Wide operating temperature
- High specific energy
- Low operational voltage
- High heat generation
- Voltage delay
- Poor low-temperature performance
The most common applications of CFx batteries are in interventional medical devices. It is also sometimes used in implantable medical devices such as cardiac pacemakers.
Lithium Iron Phosphate (LiFePO4) Battery
A Lithium Iron Phosphate battery has a Lithium Iron Phosphate cathode and a graphite anode. It is one of the most innovative and advantageous forms of lithium iron phosphate battery. It is also known as LiFePO4 or LFP battery. LFP batteries are commonly available as a rechargeable lithium-ion battery option.
- High depth of discharge
- High energy density
- Low self-discharge rate
- High safety standard
- Long service life
- Operation in sub-zero temperature
The deep-cycle nature of LFP batteries finds applications in portable medical devices, surgical tools, and many other types of life-sustaining devices.
Nickel Metal Hydride Battery
A nickel metal hydride battery is a type of rechargeable battery with a positive terminal made of nickel oxide hydroxide. The negative electrode is made of a hydrogen-absorbing alloy.
- Significantly higher capacity than Nickel Cadmium batteries
- High energy density compared to NiCd
- Fast charged
- Very low cycle life
- High heat dissipation
- Prone to overcharging damages
- High self-discharge (10% in one day)
- Low capacity and energy density than a rechargeable lithium-ion battery
Nickel Metal Hydride batteries make rechargeable cells for powering small devices. There are various form factors, such as prismatic, button, and cylindrical cells.
Nickel Cadmium Battery
A Nickel-cadmium battery is a type of rechargeable battery with a positive terminal of nickel oxide hydroxide, similar to Nickel Metal Hydride batteries. However, the negative terminal is made of a cadmium metal electrode.
- Fast recharge
- Presence of toxic materials
- Lower capacity and energy density
Nickel Cadmium batteries make rechargeable cells for smaller medical devices such as blood pressure monitors and diabetic monitors. Small scale portable medical devices also use nickel cadmium batteries.
An alkaline battery is a type of non-rechargeable batteries developed in smaller cylindrical sizes. Instead of using an acidic electrolyte, these batteries rely on an alkaline electrolyte solution with pH of over 7. These batteries are generally made of zinc and manganese oxide. The reactions between these materials drive the currents in the battery. There are a few rechargeable alternatives of these batteries available in the market.
- Good shelf life
- Safe and easy to transport
- Good low-temperature operation
- Very low capacity
- Requires frequent replacement
- Not environmentally friendly
- Low capacity
Commonly used areas for alkaline batteries are BP monitors, pulse oximeters, and infusion pumps.
Zinc Air Batteries
A zinc air battery is a type of non-rechargeable battery that generates current with the oxidation of zinc. The oxygen for oxidation is received from the air. In medical applications, zinc air batteries are used for making smaller button cells.
- Easy to store and transport
- Very high volumetric energy density
- Limited service lifetime
- Varying performance depending on ambient conditions
- Flooding potential
- Low capacity
Zinc air batteries are used where the medical devices’ size prohibits using other battery alternatives. The most common medical application of a zinc-air battery is for powering hearing aids.
Important Parameters for Medical Batteries
Focusing on some basic parameters of medical batteries can help optimise their performance. These parameters are:
- Cycle Life: Longer cycle life means that a battery can last longer. This provides a better return on the investment. Additionally, it also reduces the number of battery replacements required, saving precious time.
- Shelf Life: Shelf life indicates how long the battery can be stored without using it. Longer shelf life is useful because medical applications require storage of spare options.
- Safety: Batteries with good safety standards ensure that no equipment malfunction occurs. For instance, nickel metal hydride batteries are susceptible to overcharging, which can damage the battery and the medical devices using it.
- Environment Effect: Rechargeable lithium-ion battery is the most environmentally friendly option, especially when compared to alternatives like the lead acid battery.
- Regulatory Compliance: The battery you use must meet the regulatory compliances for the healthcare sector. These compliances will be discussed in the sections to come.
- Self-discharge Rate: Self-discharge rate is an essential parameter for implantable medical devices or devices that undergo long storage periods.
Safety Standard for a Medical Battery
Medical batteries require several safety measures to protect the battery, equipment, and the user. The various safety standards for medical batteries are:
- Short-circuit Protection
- Overcharge Protection
- Thermal Protection
- Cell Balancing
- Reverse Polarity Protection
- Venting Mechanism
- Regulatory Compliance
What is the Lifespan of Medical Batteries?
Medical batteries can last anywhere from a few weeks to over 15 years. The exact lifespan varies depending on the type of battery being used. For instance, alkaline batteries may require replacement after a few weeks of regular usage. On the other hand, lithium-ion batteries last for over five years. Quality LFP batteries push this limit with a lifespan of 15 years and more.
Regulatory Requirements for Medical Batteries
Several regulations are set in place to ensure the medical batteries you use have a certified safe operation. These regulations are:
- FDA Regulations: The US Food and Drug Administration regulates the use of medical devices and their components, including medical batteries. For medical applications in the US, batteries must have FDA approval. An FDA approval means the battery has a high safety and quality standard.
- ISO 13485: The International Organization for Standardization (ISO) also has specific regulations to ensure medical battery safety. The ISO 13485 section, in particular, details the design and development of all medical devices and their batteries.
- IEC 60601-1: IEC 60601-1 is an international standard that regulates the performance of a medical device using electricity. This section mainly refers to primary batteries for medical use. Besides the design and quality, this standard also details the construction requirements for the battery.
- UL 1642: The UL 1642 is a safety regulatory standard specifically for lithium-ion batteries. Compliance with the UL 1642 regulation means that the lithium battery is safe from a thermal, chemical, mechanical, and electrical standpoint.
- IEC 62133: IEC 62133 is an international regulatory standard for secondary medical batteries. The equipment under this purview is portable medical devices. A battery that complies with IEC 62133 is a good fit for portable medical devices.
- RoHS Directive: RoHS stands for Restriction of Hazardous Standards. It regulates the use of hazardous materials in batteries and aims to reduce such materials. Commonly used hazardous materials in batteries are cadmium, mercury, and lead.
What Factors Determine Medical Device Battery Performance?
Several factors influence the performance of medical device batteries. These factors are:
- Power: The battery’s power is the primary criterion that determines battery performance. A higher-power battery will provide a longer life. For rechargeable batteries, high battery power means a longer running time on a single charge.
- Battery Chemistry: Lithium ion chemistry is the top performer in medical batteries. These batteries are rechargeable in nature and provide a very long service life. Therefore, external lithium-ion battery packs perform better than internal battery cells of alkaline or nickel-based battery chemistries.
- Operating Environment: Factors like temperature and humidity can influence the health and performance of the battery. Many batteries struggle in providing adequate performance in low-temperature currents. Furthermore, a humid operating environment can corrode the battery terminals, reducing performance.
- Load Profiles: The load variation with time also plays a vital role in battery performance. Increasing the load will reduce the working time of the battery.
- Discharge Rate: Every battery comes with a limit on the discharge rate. Discharging the battery at a higher rate will significantly degrade its performance.
- Battery Age and Usage: Every battery degrades with age and usage. As the battery approaches the end of its lifespan, it is common to see a significant reduction in performance. However, the rate of performance degradation varies depending on the battery chemistry. Lithium battery chemistries show performance degradation after many years. On the other hand, lead acid batteries can show signs of degradation after a few months.
- Charging System: It is essential to charge the battery systems with the charger recommended by the manufacturers. Not using the appropriate charging system can lead to underperforming battery systems.
- Quality and Reliability: A high-quality battery from a reliable manufacturer means an optimally performing product. Inferior batteries can save some money but last for only a fraction of the lifespan, and that too at reduced performance. This leads to poor cost-effectiveness in comparison to branded batteries.
- Maintenance and Handling: The battery handling and maintenance protocol can be the difference between a battery failing mid-operation and one lasting way over its expected lifespan. In general, lithium-ion battery technology is the easiest to maintain.
Are There Any Specific Disposal or Recycling Requirements for Medical Batteries?
Yes, medical batteries require a specific disposal and recycling process. The exact steps for disposal depend on the type of battery being used. Batteries containing hazardous materials like cobalt or cadmium may require additional disposal precautions. Generally, any medical battery should not be disposed of in the generic rubbish container.
How to Prevent Medical Device Battery Leakage and Contamination?
Battery leakage is a common phenomenon. However, it can create additional complications in the medical areas, leading to contamination risks. Therefore, preventing the leakage of battery systems is crucial. Here are some tips in this regard:
- Using the Right Chemistry: Leakage is present only in specific battery chemistries, like the lead acid battery. Opting for a leakage-free option like the LFP battery can solve your worries.
- Protective Casing: It is common for leakage to occur when the battery receives damage due to physical bumps and shocks. A protective casing can prevent it from happening. The protective casing also ensures that any leakage that occurs is contained.
- Battery Monitoring: Overcharging the battery can damage it permanently and cause battery leakage. Monitoring the battery can avoid this problem. Eco Tree Lithium’s LFP batteries have an inbuilt Battery Management System (BMS) to solve this issue.
- Proper Installation: Any shortcomings in battery installations that lead to wobbly batteries can cause battery leakage in the future. Therefore, ensure proper installation steps as recommended by the manufacturer.
- Regular Maintenance: Follow a regular maintenance cycle to keep your battery in the optimal state. For instance, it is essential to lubricate the terminals regularly in case of external battery packs.
Which Medical Devices Require Batteries?
Most electronic devices in the medical industry rely on batteries for operating functions. Some of these devices are:
- Portable X-ray Machine
- Electrocardiogram (ECG) Machine
- Hearing Aids
- Portable Nebulizers
- Patient Monitors
- Hearing Aids
- Electronic Stethoscope
- Insulin Pump
- Foetal Doppler
- Infusion Pumps
- Ventricular Fibrillation
- Blood Glucose Metres
- Portable Suction Units
- Wearable Continuous Glucose Monitoring Systems
How Do Medical Batteries Differ From Consumer Grade Batteries?
The primary difference between consumer-grade and medical batteries is that the latter must adhere to multiple regulations. The purpose of medical devices is to sustain vital life functions. Therefore, medical batteries are designed with particular emphasis on safety. There are added precautions and safeguards mechanically, electrically, and chemically.
The proper functioning of medical devices directly improves the quality of healthcare service. With the information provided above, you can now make the right decision when choosing between different types of medical batteries. Whether using lithium-ion cells or any other alternative, remember to use a quality supplier such as Eco Tree Lithium for the best performance.
Frequently Asked Questions (FAQs)
Here are the answers to some common questions regarding batteries for medical devices:
What advancements have been made recently in battery technology for medical devices?
Recent medical device battery technology advances have been towards eliminating toxic or hazardous materials. In this direction, batteries containing harmful elements like lead and cadmium are actively replaced by primary lithium batteries.
What are some common signs that a medical battery needs to be replaced?
Battery leakage is a common sign that a medical battery requires replacement. Other common signs are swollen battery, pungent smell, or reduced battery capacity.
How does the energy demand of a medical device affect the choice of battery?
The energy demand of a medical device significantly affects the choice of the battery. When the energy demand increases, batteries of larger capacity are required. Another option is to increase the number of batteries.
What are the most commonly used battery types in the medical industry?
Lithium batteries are the most common battery types in the medical industry. Lithium batteries provide several benefits over other alternatives, such as a long life. Among the various types of lithium batteries, LFP batteries are the most preferable option for medical applications.