A lithium-ion battery is a type of rechargeable battery that makes use of charged particles of lithium to convert chemical energy into electrical energy. M. Stanley Whittingham, a British-American chemist is known as the founding father of lithium-ion batteries. He developed the concept of rechargeable batteries during the late 1970s. In 2019, M. Stanley Whittingham, John Goodenough, and Akira Yoshino were awarded the Nobel prize in chemistry for their work. On the basis of the ability of recharging, lithium-ion batteries can be classified into two broad categories, namely, primary and secondary. Primary lithium-ion batteries are non-rechargeable, while secondary lithium-ion batteries are rechargeable.
Working Principle of Lithium-ion Battery
Lithium-ion batteries work on the rocking chair principle. Here, the conversion of chemical energy into electrical energy takes place with the help of redox reactions. Typically, a lithium-ion battery consists of two or more electrically connected electrochemical cells. When the battery is charged, the ions tend to move towards the negative electrode or the anode. When the battery gets completely discharged, the lithium ions return back to the positive electrode, i.e., the cathode. This means that during the charging and discharging process, the lithium ions move back and forth between the two electrodes of the battery, which is why the working principle of a lithium-ion battery is called the rocking chair principle.
Working of Lithium-ion Battery
A battery typically consists of two electrodes, namely, anode and cathode. Cathode forms the positive terminal of the battery and anode is dedicated as the negative terminal. The cathode of a lithium-ion battery is mainly composed of a lithium compound, while the prime element of the anode is graphite. When the battery is plugged in with an electric supply, the lithium ions tend to move from the cathode to the anode, i.e., from the positive electrode to the negative electrode. This is known as charging the battery. During the discharge phase of the battery, the movement of the lithium ions gets reversed from anode to cathode, i.e., from negative electrode to positive electrode, and the electrical energy gets transmitted to the attached load.
Uses of Lithium-ion Battery
Cellular Devices
Almost all cellular devices such as mobile phones, laptops, cordless phones, etc., make use of lithium-ion batteries. This is because lithium-ion batteries are compact, lightweight and reusable. Hence, they are perfectly fit for handheld devices. Also, such types of batteries provide a quick charging rate, thereby allowing the user to access the devices frequently without disturbance.
Power Banks
A power bank is a portable gadget that helps the user to conveniently charge electronic devices such as mobile phones, smartwatches, etc., anywhere and anytime. For this purpose, a power bank typically makes use of lithium-ion and lithium-polymer batteries.
Electric Vehicles
A number of electric vehicles such as electric cars, electric bikes, electric scooters, electric cycles, etc., employ lithium-ion batteries for their operation. This is because lithium-ion batteries have a high power-to-weight ratio, greater tolerance to temperature and pressure variation, and a higher energy density than lead-acid batteries. Also, they are light in weight, portable, efficient, and safer than traditional batteries.
Medical Devices
Medical devices such as hearing aids, surgical tools, diagnostic machines, pacemakers, defibrillators, Medical assistant robots, infusion pumps, heart and pulse rate monitors, etc., employ lithium-ion batteries for various diagnostic and treatment purposes. The advantages of using lithium-ion batteries in medical gadgets include high responsiveness, quick charging rate, lightweight, and non-hazardous nature, etc.
Cameras
Lithium-ion batteries are highly used in digital SLR cameras because they are able to provide high power for a comparatively longer duration than traditional batteries. Also, lithium-ion batteries are preferred because they are light in weight, hence do not make the gadget bulky. Some of the cameras also make use of rechargeable lithium-ion batteries that enables the user to reuse them and improve reliability.
UPS
A UPS (uninterrupted power supply system) is a device that provides a power backup for a certain time period in case of a power cut or failure. Such devices typically make use of a combination of lithium-ion batteries. This is because the use of lithium-ion batteries in UPS devices reduces the floor space by 50-80%. Also, a lithium-ion battery-based UPS system weighs 60-80% less than a generic lead-acid-based UPS device.
Robots
Lithium-ion batteries are highly preferred in the robotics and automation field of science. They are used to power humanoid robots as well as industrial robots.
Advantages of Lithium-ion Battery
1. Lithium-ion batteries have a significantly low self-discharge rate as compared to the other type of batteries.
2. They have a high energy density.
3. There exists no memory effect in lithium-ion batteries.
4. The average life span of lithium-ion batteries is ten times more than the traditional lead-acid batteries.
5. The charging rate of lithium-ion batteries is high.
6. Lithium-ion batteries work efficiently under extreme conditions such as high pressure and temperature fluctuations.
7. Lithium-ion batteries are lightweight and compact in size. Typically, the weight of lithium-ion batteries is roughly 50-60% less than the standard lead-acid batteries.
8. Installation of lithium-ion batteries is comparatively easy.
9. These types of batteries are flexible, less bulky, and safe to use.
10. Lithium-ion batteries are available in a variety of shapes and sizes.
11. The voltage level of a lithium-ion battery does not drop and is maintained constantly throughout the use.
12. The capacity of a lithium-ion battery is approximately 25-50% more than the lead-acid battery.
13. They require low maintenance.
14. Lithium-ion batteries are non-hazardous as they do not emit any toxic gas.
Disadvantages of Lithium-ion Battery
1. The charging capacity of a lithium-ion battery gets reduced over time because of the loss of lithium ions in the solid electrolyte interphase and cathode-electrolyte interphase.
2. If the separator of the lithium-ion batteries gets damaged, they are susceptible to fire hazards.
3. They are relatively expensive.
4. If the battery runs out of lithium ions, it can not be replaced. Thus, the battery cannot be used after the tentative life span.