What Is The Principle of Lithium-ion Battery, What Are The Advantages And Disadvantages of Lithium-ion Battery?

With the increasing demand for electric vehicles, the use of lithium-ion batteries has become the biggest trend in today's electric vehicle market. The lithium-ion battery is precisely the use of lithium ion movement in the dielectric to the positive and negative electrode transport between the principle of energy storage and release of energy operation.

Lithium-ion batteries, which are composed of a variety of materials, have superior characteristics such as light weight, high energy density and environmental protection, and are favoured by the majority of users. It is based on the principle of lithium-ion batteries as well as technical advantages, making lithium batteries in electric vehicles, smart phones, laptops and other fields are gradually being applied, and has greater potential to be used in storage to solve the problem of power stations accounting for more than 45 per cent of the total amount of electricity, the development of a huge.

How do lithium-ion batteries work?

With the continuous progress of science and technology, lithium-ion batteries have become one of the most commonly used batteries in modern life, whether it is mobile phones, computers, tablets or other smart devices, can not do without lithium-ion batteries. So how do lithium-ion batteries actually work? Let's explore its working principle from the following five sub-headings.

1: The structure and composition of the battery

The structure of a lithium-ion battery consists of three main parts, namely the positive electrode, negative electrode and electrolyte. The positive electrode is usually lithium cobaltate (LiCoO2), the negative electrode is made of graphite or graphite-like materials, and the electrolyte is made of organic solution or polymer film. In addition, the battery includes components such as connectors and a metal case.

When the battery is charged, lithium ions move from the positive electrode to the negative electrode while the negative electrode releases electrons, which flow into the circuit to complete the charge. When discharging, lithium ions move from the negative electrode to the positive electrode, and in the process, the battery releases energy to power the device.

2: Principle of Battery Charging

When charging, an applied electric field is applied between the positive and negative electrodes of the battery, causing lithium ions on the positive electrode to begin to flow into the electrolyte and move along the electrolyte concentration gradient towards the negative electrode. At the negative electrode, the lithium ions will again combine with electrons and become ‘lithium atoms’ embedded in the negative electrode material. During the whole charging process, the negative electrode is more stable, which is mainly reflected in the positive electrode, i.e. lithium cobalt as the positive electrode material will be in a higher valence state in the charging state.

3: Battery discharge principle

When the battery is connected to a load circuit, electrons flow out of the positive electrode of the battery, and a chemical reaction occurs in the positive electrode material, reducing the lithium cobaltate to a lower valence state and releasing lithium ions at the same time. These lithium ions leave the positive electrode and move along the concentration gradient in the electrolyte towards the negative electrode, where they combine with the lithium in the negative electrode material and form ‘lithium atoms’ embedded in the negative electrode material.

4: Internal resistance of the battery

Like other batteries, lithium-ion batteries also have internal resistance during operation, which is caused by the influence of the electrolyte, battery case and connectors on the current channel. Therefore, the actual output voltage of lithium-ion batteries will be lower than the theoretical voltage, and with the growth of the battery use time, the internal resistance of the battery will become larger and larger, thus reducing the life of the battery.

In order to adapt to different load circuits, batteries and battery packs usually need to be equipped with a circuit to match the load circuit. Specifically, the appropriate load resistance can effectively reduce the internal resistance of the battery and increase its output voltage.

5: Battery safety performance

Although lithium-ion batteries have the advantages of high energy density and long cycle life, there are corresponding safety hazards. Lithium-ion batteries may be activated under violent passivation, overcharging and discharging, short circuit, etc., and trigger gasping and hydrolysis reactions during the discharge process, and may even trigger bursting, burning and other dangerous events in serious cases.

Therefore, in order to ensure that lithium-ion batteries work in a safe and reliable environment, it is necessary to take a series of safety measures, such as increasing the protection circuit inside the battery, using high-quality materials, designing a reasonable battery casing, and adopting safe transport methods.

What are the advantages and disadvantages of lithium-ion batteries?

Lithium-ion batteries are currently one of the most commonly used batteries and are widely used because of their small size, light weight, high storage energy density and environmental protection. However, accordingly, there are also shortcomings such as high cost, short service life, and easy to overheat and catch fire. In this paper, we will discuss the advantages and disadvantages of lithium-ion batteries from various aspects, so that readers can have a more in-depth understanding of them.

1: High energy density

Compared to traditional batteries, lithium-ion batteries have a higher energy density. This means they can provide more energy storage for the same volume or weight in devices such as mobile phones, tablets, laptops and drones.

The high energy density also makes lithium-ion batteries widely applicable in electric vehicles. Electric vehicles need sufficient power reserves to travel longer distances, and lithium-ion batteries are more suitable for electric vehicles than other batteries.

2: Lightweight and easy to carry

Lithium-ion batteries are smaller and lighter than other batteries.

In today's era of people pursuing portability and lightweight, lithium-ion batteries have been widely used. Such as smart watches, smart homes, drones, etc., all need batteries that are light and portable so that they can be carried and used.

3: No memory effect

The ‘memory effect’ is the phenomenon that the charge receiving ability of the battery of electronic products decreases after being repeatedly charged and discharged. Lithium-ion batteries do not have this problem, no matter when, as long as the power is depleted, can be recharged to use.

In addition, the use of lithium-ion battery products can accurately display power information, the user can accurately predict the remaining use time and charging time, more convenient for practical use.

4: Environmentally Friendly

Compared with traditional dry batteries and nickel-metal hydride batteries, lithium-ion batteries have better environmental performance. Because they do not require the metal mercury or cadmium, it is easier to recycle and dispose of waste.

5: Fast charging speed

Compared to other batteries, lithium-ion batteries charge faster. For users, this means shorter charging times and longer usage times.

At the same time, modern technology is constantly improving the charging speed of lithium-ion batteries, and even faster charging technology is expected to come out in the future.

6: High cost

Lithium-ion batteries are more expensive compared to dry cell and nickel-metal hydride batteries due to the high cost of production. This means that costs need to be carefully assessed before any product is mass produced.

At the same time, due to the increased demand for materials used in the manufacture of lithium-ion batteries, the price of raw materials fluctuates, leading to instability in the market price of lithium-ion batteries.

7: Short Use Life

Compared to some other batteries, lithium-ion batteries have a shorter lifespan, which is shortened as the number of times they are used increases. A common phenomenon is that the storage capacity of the battery gradually decreases over time.

Therefore, at the beginning of the design of the equipment, it is necessary to avoid frequent charging and discharging as much as possible in order to extend the battery life.

8: Easy to overheat and catch fire

A serious problem with lithium-ion batteries is that they can overheat and catch fire. Although modern technology and design has been as far as possible to solve this problem, such as the use of high coolness of the battery, fire-resistant materials. However, due to the chemical characteristics of lithium-ion batteries, they are still prone to react at high temperatures, forming a large amount of heat to further aggravate the overheating situation.

In addition, if the battery is not used correctly or damaged, it will also increase the risk of overheating and fire, so the use of lithium-ion batteries should be extra careful.

Why have lithium-ion batteries become the dominant battery type?

Today, many of the devices we use in our daily lives use lithium-ion batteries, such as mobile phones and laptops. So why have lithium-ion batteries become the mainstream battery type? Next, we will elaborate this question from five aspects.

1.high energy density

Lithium-ion batteries have a higher energy density compared to other batteries. Because lithium ions in the battery discharge, free electrons in the electrolyte to move to the positive electrode, resulting in a decrease in battery potential. As the battery potential decreases, lithium ions leave from the positive electrode and are embedded in graphite at the negative electrode, thus completing the charge cycle. As a result, lithium-ion batteries have a higher energy density, which can provide longer life for portable devices.

In addition, high energy density makes lithium-ion batteries widely used in lightweight devices, such as smart watches and smart glasses.

2.low self-discharge rate

Lithium-ion batteries have a low self-discharge rate when they are not charged or used. Other battery types, on the other hand, often experience power degradation, which affects their lifespan. For example, nickel-metal hydride batteries lose about 2% of their charge every day, while the self-discharge rate of lithium-ion batteries is only 1% per month.

As a result, lithium-ion batteries are ideal for use in devices that need to be left in place for long periods of time. For example, wireless cameras and security systems.

3, environmental protection and safety

Compared with other battery types, lithium-ion batteries have less impact on the environment and are safer. Compared to other batteries, lithium-ion batteries have no mercury, lead or cadmium, and will not pollute soil and water.

In addition, although lithium-ion batteries may overheat or short-circuit, a series of measures taken in the design and production stage, such as protective circuitry and temperature control systems, can make lithium-ion batteries more safe and reliable.

4. long life

Lithium-ion batteries have a long service life, thanks to their materials and assembly methods. The positive material of lithium-ion battery is cobalt, nickel, manganese, iron or lithium iron phosphate, while the negative material is graphite. Not only do these materials provide efficient energy conversion, they also have a high cycle life, providing long-lasting use of the device.

Under normal use and storage conditions, lithium-ion batteries can last for several years. The life cycle of a lithium-ion battery is calculated by the number of charge and discharge cycles. In fact, lithium-ion battery life can be optimised by minimising the number of complete discharges and charges. Therefore, it should be used in a way that avoids too low or too high a charge.

5. Wide range of applications

In addition to consumer electronics such as smartphones and laptops, lithium-ion batteries are also widely used in drones and electric vehicles. Lithium-ion batteries are widely used in electric vehicles and other aircraft because their high energy density and lightweight design greatly reduces the weight of electric vehicles and drones. In addition, lithium-ion batteries are also suitable for use in portable power supplies as well as spacecraft.

The lithium-ion battery principle is one of the key points in the field of battery technology today, which, unlike traditional lead-acid batteries, achieves greater power density and longer cycle life. Through in-depth study of the working principle of lithium-ion batteries, we further understand its application prospects in the fields of energy conservation and environmental protection, new energy vehicles and renewable energy. We also found that lithium-ion batteries face many technical and market challenges from innovation to market implementation, and researchers in various industries around the world are continuously improving the process and optimising the cost-effectiveness of lithium-ion batteries.

In summary, lithium-ion batteries, as a hot topic in battery technology today, are widely used and enable cross-border applications in a variety of fields. Whether we are researchers or the general public, on the basis of a full understanding of its principles, more promotion and application of lithium-ion batteries will play a positive role in energy saving, emission reduction and sustainable development of mankind.