The development of small medical devices that have numerous features has led to a rise in demand for dependable and affordable power management solutions. Medical devices companies have turned to lithium battery technology as the solution to this need. Such as Large medical lithium battery.
What are the Lithium Batteries?
Lithium batteries are referred to as primary batteries that use metallic lithium as an anode. They range in size depending on their use. There are small and large medical lithium batteries. The batteries are used in single-use devices and also in devices that require a long battery life. This site large.net/medical presents examples of the batteries.
Lithium batteries come in different chemistries. This is because some devices need to be small and lightweight and others need to be big making them have different power needs. Some lithium chemistries are well suited to high temperatures in devices related to autoclave sterilization cycles while others are suited to devices operating in low temperatures required in the medical cold chain.
Why use lithium?
Lithium was in introduced in medicine back in the 1960s when it was used to power pacemakers. Currently, lithium batteries power all medical devices including external defibrillators, glucose monitors, infusion pumps, and blood oxygen meters among many others.
One of the reasons that lithium batteries are preferred in advanced medical devices is due to the fact that they offer the highest energy per unit weight and energy per unit volume when compared to other batteries. The lithium cells utilize a non-aqueous electrolyte. They also possess a nominal open circuit with voltages ranging from 1.7 to 3.9 volts.
Another reason is the lithium chemistries. Lithium batteries lack water, and the chemical and also its materials possess physical stability. This enables the different chemistries to offer an extended temperature range. Some cells can be modified to adapt to temperatures of below -70 ºC to support the medical cold chain. This allows the monitoring of transplant organs among other uses.
Lithium Chemistries
There is a variety of lithium chemistries in lithium batteries, and each has its benefits and shortcomings. These chemistries include:
- Lithium manganese dioxide batteries (Li/MnO2). Cells with this type of chemistry were initially built for items such as cameras. Now they have been adopted in the medical industry and specifically in devices such as glucose monitors. The cells with this chemistry are comparatively cheap and have high current-pulse capabilities. However, they are significantly affected by self-discharge and low energy density. Their temperature range is also limited to between -10 ºC and 60 ºC.
- Lithium-sulfur dioxide batteries (Li/SO2). These type of cells are commonly found in devices such as external defibrillators. Their chemistry is larger and heavier compared to the others, and it enables them to deliver high current pulses even at low temperatures. These batteries are also affected by self-discharge, and as a result, they have a limited service life.
- Lithium thionyl chloride batteries (Li/SOCl2). The chemistry in these type of cells makes them ideal in low-current applications. They are able to apply a constant low currently over a long period. These cells possess high energy density low self-discharge rate and high capacity. They have a potential operating life of over 25 years. Some of these cells can be adapted to operate in temperatures of -80 ºC and 125 ºC.
- he PulsesPlus battery. This type of cell is a hybrid of lithium thionyl chloride cell. It combines the advantages of the chemistry with a hybrid layer capacitor, and this allows it to deliver high current pulses. Due to these features, this battery is well suited for use in automatic external defibrillators since these devices operate with a low background current but need high current pulses from time to time.
This cell also has another feature that allows it to offer an indication of the end-of-life when its original capacity has been depleted by about 90% -95%. This feature is useful in some applications where the device’s readiness status needs to be assessed continually.
Applications of Lithium Chemistry
The following are some examples of how lithium chemistry is essential in various applications.
- Bone growth stimulator. This device requires a low and continuous current to produce low-intensity, pulsed ultrasound. This type of equipment uses a battery pack made up of Li/SOCl2 to deliver constant and long-term power. This battery also has a high energy density which ensures a reduced size and weight which is essential because this device needs to be worn by the patient.
- Automatic External Defibrillators (AEDs). This device needs a low background current and also very high current pulses when being used. The device is used on patients in cardiac arrest to restore normal heart rhythm.
- Automatic External Defibrillators (AEDs). This device needs a low background current and also very high current pulses when being used. The device is used on patients in cardiac arrest to restore normal heart rhythm.
PulsesPlus hybrid Li/SOCl2 batteries are used since they can deliver the required high-current pulses to stimulate the human heart. They also have a low self-discharge and an ability to operate in extreme temperatures. They are very reliable, and that’s why they operate in a situation where battery life can cause the death of a patient.
- Hand-held surgical drill. This drill needs no background current but requires very high current pulses. The device uses TLM-1150HP batteries. These batteries are made from lithium metal oxide and deliver an open circuit voltage of about 4.1 V. They also have the ability to withstand high current pulses.
The lithium metal oxide batteries provide faster drilling speeds, increased drilling time and also increased drilling torque.
- Sterilizable RFIDs. These are devices that are used to monitor the vital signs of patients and track their location through satellite. They use lithium thionyl chloride batteries that can withstand high temperatures in an autoclave and chemical sterilization cycles. This ensures continuous real-time tracking and reporting since the batteries don’t have to be removed during sterilization.
Conclusion
Continuous advancements in lithium battery technology play an essential role in the revolution of the medical industry. Evolving medical technology leads to expanding possibilities and challenges that involve long-term management solutions. This will influence the performance as well as the reliability of future medical devices.
