Non-polluting green battery - lithium battery

In 1860, the French scientist Lechranche invented dry batteries to unveil a new era of chemical power. The positive electrode material of the dry battery is manganese dioxide, and the carbon rod is used as the positive electrode conductor, and the negative electrode is the zinc tube, which is both a negative electrode and a container. The electrolyte is a mixture of zinc chloride and ammonium chloride. The terminal voltage of the dry battery is 1.5 volts. For more than 100 years, dry batteries have benefited humans in radios, lighting, flashlights, calculators and home appliances, and today it is an indispensable chemical power source for everyday use. However, since the dry battery is a primary battery, it cannot be charged, and it is discarded when it is used up, causing environmental pollution. The invention of the lithium battery overcomes the shortcomings of the dry battery and is a rising star of the battery.

I ask what kind of battery is installed in the laptop. What is the power supply of the mobile phone? What is the chemical power supply installed in the digital camera? The answer is one: it is a lithium battery. The earliest invention of lithium batteries was the great inventor Edison, but due to the technical limitations of the time (100 years ago), and because metal lithium was the most active chemical element, Edison could not make a battery with practical value. It was not until 1973 that the world's first lithium battery with practical value was produced. Initially, lithium batteries were only used in cardiac pacemakers. Because the self-discharge rate of lithium batteries is extremely low, the discharge voltage is stable, so that the heart pacemaker can be used for a long time after being implanted into the human body by means of a knife. For example, the battery has not been replaced for more than 10 years. Due to the invention of the lithium battery, thousands of heart disease patients have been saved, and they have returned to life and prolong their life.

Since the first cardiac pacemaker was introduced in 1966, it has been more than 40 years old. Hundreds of thousands of cardiac pacing have been implanted into the human body through surgery, prolonging the lives of heart patients, and being safe and reliable. Welcome. The power source of the cardiac pacemaker was originally a zinc-mercury battery. This battery is small in size and long in life, but it has mercury. In 1980, a cardiac pacemaker made of lithium-iodine battery in foreign countries has a working life of more than ten years. It is used as a power source for heart pacemakers. It is mercury-free, pollution-free, safe and reliable. It is the gospel of heart patients.

In 1973, the advent and application of lithium batteries unveiled another new era of chemical power. Lithium batteries have high energy density, light weight and good electrical conductivity, and are characterized as no pollution to the environment. It has been used in large quantities since its inception, and it is an emerging chemical power source. In order to develop a variety of lithium battery products with better performance, various materials have been studied. So that it creating an unprecedented product. For example: lithium sulfur dioxide (Li-SO2) batteries and lithium thionyl chloride (Li-SOCl2) batteries. Its positive active material is also a solvent for the electrolyte. This structure only occurs in electrolytes that are not aqueous. So, why does a lithium battery have such a great power, what kind of material is it made of, and how is it constructed? Why does it have those excellent characteristics compared with other batteries? The main difference between the original lithium battery and other batteries is that it Metal lithium or lithium alloy is used as the negative electrode material, and lithium battery is named because it uses lithium metal or lithium alloy as the negative electrode. Why do people choose metallic lithium as the negative electrode? The reason is that lithium is located in the first main group of the second cycle of the chemical periodic table. The chemical element symbol of lithium in the paper format template essay is Li, the electronegativity of lithium is 0.97, and the standard electrode potential is -3.02 volts. Among all metals, the standard electrode potential of lithium is the most negative, so lithium and other substances are applied. The battery is composed of the highest voltage among all metals, that is, up to 3.6 volts. The ordinary battery (such as ordinary dry battery-zinc-manganese battery) has a voltage of only 1.5 volts. That is to say, the voltage of a lithium battery is more than twice that of a normal battery.

In 1992 AD Sony successfully developed lithium-ion batteries and successfully applied to mobile phones and notebook computers. The weight and volume of these portable electronic devices are greatly reduced, and the use time is greatly extended. Since the lithium battery does not contain heavy metal chromium, it does not cause pollution to the environment. Is a veritable green battery

Green battery without pollution

Lithium battery characteristics

The lithium battery does not contain heavy metals such as cadmium, chromium, lead, mercury, etc. It is a green battery without pollution. In addition, lithium batteries have the following characteristics:

1. Has a high weight-to-energy ratio and volume-to-energy ratio: meaning that the lithium battery is small in weight and volume, but emits a large amount of electrical energy. Use electric energy as the numerator, weight or volume as the denominator. Due to the large size of the molecule, the denominator is small and the ratio is large. For example, a lithium battery with the same energy compared to a lead-acid battery has a weight and a volume of only one quarter of that of a lead-acid battery. Therefore, lithium batteries are both lightweight and high in power, and will inevitably replace bulky lead-acid batteries in the future. 2. Self-discharge is small and can be stored for a long time, which is the most outstanding advantage of the battery;

3. No memory effect. Lithium batteries do not have the so-called memory effect of nickel-cadmium batteries, so lithium batteries do not need to be discharged when charging;

4. Long life. Under normal working conditions, the number of cycles of charge and discharge of a lithium battery is much greater than 500 times;

5. Can be charged quickly. Lithium batteries can usually be charged with a current of 0.5 to 1 times, which shortens the charging time to 1-2 hours;

6. Can be used in parallel;

7. Because the battery does not contain heavy metal elements such as cadmium, pencil and mercury, it is environmentally friendly and is the most advanced green battery in the world.

8. Wide operating temperature range. Can work from -55C to +75C.

9. The cost is high. Compared with other rechargeable batteries, lithium batteries are more expensive.

The chemical reaction mechanism of lithium battery:

There are many types of lithium batteries. The more practical lithium batteries are: lithium polyfluorinated graphite batteries, lithium manganese dioxide batteries, lithium sulfur dioxide batteries and lithium thionyl chloride batteries, and lithium ion batteries developed by Sony in 1992. Now with lithium - A polyfluorinated graphite battery is taken as an example to illustrate the electrochemical reaction mechanism of a lithium battery:

Positive reaction:

(CF)n+ne-=nC+nF

Negative reaction:

nLi→nLi—+ne

Total battery response:

(CF)n+nLi→nC+nLiF

Lithium manganese dioxide batteries are the most widely used and the cheapest lithium batteries. It uses inexpensive γ-MnO2 as a positive electrode active material dissolved in a mixed solvent of propylene carbonate (PC) and dimethyloxyethylene (DMF) at a concentration of 1M. The ratio of the two is: PC: DMF=1: 1.

The battery response of a lithium manganese battery is:

Negative reaction: Li→Li++e

Positive electrode reaction: MnO2+Li+e→MnO2(Li+)

Total battery reaction: Li+MnO2→MnO2(Li+)

Simple structure and more types

Lithium battery construction

The shape of the lithium battery is coin type, bottle type, button type and cylinder type. The inside of the battery adopts a spiral wound structure, and a very fine and highly permeable polyethylene film insulation material is spaced between the positive and negative electrodes. The positive electrode includes a lithium ion collector composed of lithium and cobalt dioxide and a current collector composed of an aluminum film. The negative electrode is composed of a lithium ion collector composed of a sheet-like carbon material and a current collector composed of a copper film. The inside of the battery is filled with an organic electrolyte solution. Safety valves and PTC components are also included to protect the battery from damage during abnormal conditions and output short circuits.

The figure below shows the structure of a cylindrical lithium battery. The battery is a lithium thionyl chloride battery.

Structure diagram of lithium-thionyl chloride battery

Ion battery is powerful

Characteristics of lithium ion batteries

In 1992, Sony (SONY) successfully opened a lithium-ion battery and applied it as a power source for notebook computers and mobile phones to unveil a new page of chemical power. Lithium-ion batteries are available in liquid lithium-ion batteries and polymer lithium-ion batteries. Among them, the positive electrode of the liquid lithium ion battery is a lithium compound LiCoO2 or LiMn204, and the negative electrode is a lithium-carbon intercalation compound. Lithium-ion battery has the advantages of high working voltage, small volume, light weight, high energy, no memory effect, small self-discharge and long cycle life. It is an ideal power source for the development of the 21st century. To sum up, lithium-ion batteries have the following characteristics:

1. The high energy density lithium ion battery weighs half of the same capacity nickel-cadmium or nickel-hydrogen battery, and the volume is 40% to 50% of nickel cadmium and 20% to 30% of nickel hydrogen.

2. High-voltage A lithium-ion battery operates at a voltage of 3.7 volts (average), which is equivalent to three nickel-cadmium or nickel-hydrogen batteries connected in series.

3. Non-polluting lithium batteries do not contain harmful metal substances such as cadmium, lead, and mercury.

4. Lithium-free lithium-ion batteries do not contain metal lithium, so they are not subject to the restrictions imposed by aircraft transportation on passenger aircraft carrying lithium batteries.

5. High cycle life under normal conditions, the charge and discharge cycle of lithium ions can exceed 500 times.

6. Fast charging uses a constant current and constant voltage charger with a rated voltage of 4.2V to fully charge a lithium-ion battery in one to two hours.

7. Long-life lithium batteries need to be fully charged and stored, and can be stored for more than half a year at 20C.

The dry battery is a primary battery. The paper will be discarded when it is used once. For the secondary battery, the service life is an important indicator to measure the performance of the battery. The secondary battery is charged and discharged once, and is called a cycle. Under a certain charge and discharge system, the number of times the battery is subjected to charge and discharge before the battery capacity reaches a certain value is called the use cycle of the secondary battery. Lithium-ion batteries have excellent storage properties and a long cycle. One of the main features of the chemical power supply is that it can discharge electricity when it is used, and it can store electricity when not in use. The so-called storage performance for secondary batteries (rechargeable batteries, called secondary batteries, for example, lead batteries and lithium batteries. The battery that cannot be charged is a primary battery, such as a three-turn battery produced by Xiamen Battery Factory). Promising prospects

The development prospect of lithium ion battery

Lithium-ion batteries have been widely used in portable appliances such as laptops, camcorders, and mobile communications due to their unique performance advantages.

At present, the developed large-capacity lithium-ion battery has been tested in electric vehicles and is expected to become the main driving force for electric vehicles in the 21st century, and will be widely used inspecial,special and energy storage.

Two conditions for the development of chemical power sources are: (1) the specific energy density of the battery is high; (2) long storage period: Leak proof, and the self-discharge rate is extremely low. Since lithium batteries have these two conditions, the prospects for development are infinite. Due to the development ofspecial,specials, laptops, mobile communications (mobile phones) and electric vehicles, new lithium batteries have sprung up.

One top two is widely used

Single-cell lithium battery application

The single-cell lithium battery has a voltage of 3.6 volts, which can replace the 3 volt power supply. Therefore, only one battery can replace the ordinary two-cell battery, and it can supply power to small household appliances such as radios, computers and digital cameras, electronic watches, etc., not only light weight, but also It takes a long time to use.

Prospects for lithium battery electric vehicles

With the development of lithium batteries, lithium battery electric vehicles and lithium battery vehicles are about to come out. At present, the electric vehicles on the road are equipped with lead storage batteries, and the service life and number of charging and discharging are far less than lithium batteries. Once a lithium battery is installed in an electric vehicle, its Mercedes speed will greatly exceed that of a lead battery electric vehicle. And the weight of the battery can be reduced by more than half. The problem of environmental pollution caused by waste batteries is extremely important. For example, the power of electric vehicles uses lead-acid batteries, which are composed of lead, sulfuric acid, and other metals and plastics. The body is bulky and contains a large amount of lead inside. Inorganic salts, which are arbitrarily discharged, will seriously pollute the soil and water sources and produce lead vapor; seriously damage the environment.

In view of this, it is imperative to develop a new practical, green and environmentally friendly power battery to replace lead-acid batteries. In this context, lithium-ion electric vehicle power batteries stand out. Because it free of cadmium, lead, mercury. No pollutants are produced during use and production to ensure good health. Electric vehicles loaded with lithium batteries also have many advantages and become an indispensable means of transportation for the family. The most important advantage is the light weight. Many consumers complain that lead-acid batteries are too bulky. A group of batteries has 20-30 kg, which is difficult for the elderly and children to carry. Lithium batteries are generally up and down seven kilograms, which is the former 1M4, and the service life is 3-4 times that of ordinary lead-acid batteries. Old people and children will move.

Lithium battery identification

Identification of secondary lithium batteries according to IEC61960 standard:

1. The battery logo consists of 3 letters followed by 5 digits (cylindrical) or a number (square)

2. The first letter indicates the negative electrode material of the battery.

3. The second letter indicates the positive electrode material of the battery.

4. The third letter indicates the shape of the battery

5. The digital cylindrical battery has five numbers representing the diameter and height of the battery, respectively.

For example, CIRI8650 indicates that the positive electrode material of a cylindrical secondary lithium battery is cobalt, having a diameter of 18 mm and a height of 65 mm.

ICP883448 indicates that the positive electrode material of a square secondary lithium ion battery is cobalt, which has a thickness of 8 mm, a width of 34 mm, and a height of 48 mm.

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