Type of power cell and its application characteristics

Lithium-powered battery is a new type of high-energy battery developed successfully in the 20th century. The negative electrode of this battery is metallic lithium, and the positive electrode is MnO2, SOCL2, (CFx) N, etc. In the 1970s, it was put into practical use. Due to its advantages of high energy, high battery voltage, wide operating temperature range, and long storage life, it has been widely used in military and civilian small appliances such as mobile phones, portable computers, cameras, cameras, etc., and has partially replaced traditional batterie. Large-capacity lithium batteries have been tested in electric vehicles and will become one of the main power sources for electric vehicles in the 21st century. They will be used inspecials,special and energy storage.

(1) The operating voltage of the single battery is as high as 3.7 V, which is 3 times that of the nickel-cadmium battery, nickel-metal hydride battery, and nearly 2 times that of the lead-acid battery. This is also an important reason why the lithium-powered battery is higher than the energy. Therefore, when forming a power battery with the same voltage, the number of series used by lithium-powered cells will be much less than that of lead-acid cells and nickel-metal hydride cells. If the number of cells in the power cell is higher, the higher the consistency requirement of the cells in the battery, the harder the life is to do. After the battery has a problem analysis during the actual use, It is generally one or two of the single cells that have problems and then cause problems with the entire group of batteries. Therefore, it is not difficult to understand why the 48V lead-acid battery has higher feedback than the 36V lead-acid battery. From this point of view, lithium electricity is more suitable for power batteries. Use. For example, 36V of lithium requires only 10 monomers, while 36V lead-acid cells require 18 monomer cells, that is, 3 12V batteries, and each 12V lead-acid cell has six single cells or six monomer cells.

Lithium power battery

Lithium power battery

(2) Light weight, larger than energy, up to 150 H/Kg, which is twice that of nickel-metal hydride batteries, and four times that of lead-acid batteries, so the weight is one third to one quarter of lead-acid batteries of the same energy. From this point of view, lithium consumes less resources. Moreover, due to the relatively large reserves of elements used in lithium manganese batteries, the cost of lithium-powered batteries may be further reduced compared to lead acid and nickel-metal hydride batteries. Lithium batteries for electric bicycles weigh 2.2-4 kg, lead-acid batteries weigh 12-20 kg, lithium electric weights are about one-fourth to one-third of lead-acid batteries, and are about 10 kg lighter than lead-acid batteries (36V, 10Ah batteries). The battery weight was reduced by 70 %, The total weight of the vehicle was reduced by at least 20 %. In addition, general lithium trams are simple electric bicycles. Because batteries and vehicles are light, batteries of the same voltage and capacity have longer mileage. Ordinary electric vehicles weigh more than 40 kilograms, while lithium-powered battery electric bicycles weigh 7 to 26 kilograms. Women and the elderly can easily move, manpower riding is also very light, sports leisure and both. (3) Small in size, up to 400 W/L, and one-half to one-third of the size of a lead-acid battery. Provides more reasonable structure and more beautiful shape of the design conditions, design space and possibilities. At this stage, due to the limitations of the volume and weight of lead-acid batteries, designers 'design ideas have been greatly constrained, resulting in the current phase of electric bicycles in the structure and appearance of "one thousand cars", similar to each other, and monotonous. The use of lithium batteries provides designers with more space and conditions to display design ideas and design styles. Of course, it also leads to various sizes of lithium-powered batteries for electric bicycles, which is not conducive to the development of lithium-powered batteries. The lithium-powered battery industry also needs to formulate national standards for lithium-ion batteries for electric bicycles as soon as possible to accelerate the replacement of lead-acid batteries by lithium-electric batteries in the field of electric bicycles. Of course, lithium batteries are different materials in the process of continuous development, and the volume of batteries in different processes is very different. How to unify is also a difficult point.

(3) The cycle life is long and the number of cycles can reach 1,000 times. In terms of capacity maintenance of 60 %, 100 % of battery batteries can be filled and discharged more than 600 times, with a useful life of up to 3-5 years, and a lifetime of about two to three times that of lead-acid cells. With the innovation of technology and the improvement of equipment, the battery life will be longer and longer, and the price will be higher and higher. (5) Low self-discharge rate, less than 5 % per month.

(4) Allow wide operating temperature range, good low-temperature performance, lithium-powered batteries can work between -20 °C and +55 °C, especially suitable for low-temperature use, while aqueous batteries (such as lead-acid batteries, nickel-metal hydride batteries) are at low temperatures, Due to the poor liquidity of electrolytes, performance will be greatly reduced.

(5) There is no memory effect, so you do not need to discharge like nickel-cadmium batteries and nickel-metal hydride batteries before each charge, and you can charge them anytime, anywhere. The depth of battery charge and discharge has little effect on the battery life and can be fully charged. Our cycle test is fully charged.

(6) It is especially suitable for power battery. In addition to the high voltage of lithium battery, the protection board of lithium battery pack can monitor each single cell with high precision, low power consumption intelligent management, perfect overcharge, Over-discharge, temperature, over-current, short-circuit protection, lock-up self-recovery, and reliable balanced charging greatly extend battery life. Other types of batteries (such as lead-acid batteries) are prone to battery overcharge and overdischarge due to battery consistency, chargers, etc. (due to cost and other reasons, lead-acid battery packs cannot Each cell is monitored and protected).

(7) Unpolluted, lithium-powered batteries do not contain toxic substances, so they are called "green batteries" and are supported by the state. With lead acid batteries and cadmium nickel batteries in the presence of harmful substances lead and cadmium, the state will inevitably strengthen supervision and management (the elimination of export tax rebates for lead acid batteries, the increase in lead resource taxes, and the restrictions on export of lead acid electric bicycles), and the corresponding enterprises. The cost will also increase. Although lithium batteries are not contaminated, they are considered from the perspective of resource conservation. Lithium-powered battery recovery, safety in recycling, and cost recovery also need to be considered. (10) There are potential security risks; Due to the high energy of lithium-powered batteries and the poor stability of materials, lithium electricity is prone to safety problems. The world-renowned manufacturers of mobile phone and notebook computer batteries (positive materials are lithium cobalt acid and ternary materials), Japanese companies such as Sanyo and Sony require that the explosion rate of batteries be controlled below 40 ppb (one-billionth of a billion). Domestic companies can reach ppm (one-millionth of a million), and the capacity of power cells is more than a hundred times the capacity of mobile phones. Therefore, the safety requirements for lithium electricity are extremely high. Although lithium cobalt acid batteries and triplex batteries have the advantages of lighter weight and smaller size, they are not suitable for use in electric vehicles.

(8) High prices; Lithium-powered batteries with the same voltage and the same capacity cost 3-4 times that of lead acid. With the expansion of the market for lithium-powered batteries, the reduction of costs, the improvement of performance, and the increase in the price of lead-acid batteries, the price of lithium-powered batteries is likely to exceed lead-acid batteries.

The material is separated between positive and negative poles. Positive poles include lithium collector consisting of lithium and cobalt dioxide and current collector consisting of aluminum thin films. The negative electrode consists of a lithium collector consisting of a sheet carbon material and a current collector consisting of a copper film. The battery is filled with an organic electrolyte solution. In addition, safety valves and PTC components are also installed to protect the battery from damage when the battery is in an abnormal state and the output short circuit.

Lithium power battery

Lithium power battery

The voltage of a single lithium battery is 3.6 V, and the capacity can not be unlimited. Therefore, a single lithium battery is often processed in series and in parallel to meet the requirements of different occasions.

With the development of Microelectronics technology in the 20th century, miniaturized equipment has been increasing, and it has put forward high requirements for power supply. Lithium-powered batteries then entered a large-scale practical phase. It was first applied to pacemakers. Due to the extremely low self-discharge rate of lithium-powered batteries, the discharge voltage is gentle. Makes it possible for pacemakers to be implanted into the human body for a long time.

Lithium-powered batteries generally have a nominal voltage of more than 3.0 volts and are more suitable for integrated circuit power supplies. Manganese dioxide batteries are widely used in computers, calculators, cameras, and watches.

Lithium-powered batteries are widely used on mobile phones and can be said to be the largest group of applications.

Examples:

1, Battery replacement There are many batteries, such as those used on laptops. After maintenance, it was found that this battery pack was damaged only by individual cells. You can use a suitable single lithium battery for replacement.

2, the production of bright miniature flashlight I used a single section 3.6 V1 .6 AH lithium battery with a white ultra-high brightness light emitting tube to make a miniature flashlight, easy to use, compact and beautiful. And because of the large battery capacity, it is used for an average of half an hour per night and it has been spent for more than two months without charging.

3, instead of 3V power supply. Since the single lithium battery voltage is 3.6 V. Therefore, only one lithium battery can replace two ordinary batteries to power small household appliances such as radios, Walkman, and cameras. They are not only light in weight but also have long continuous use.

1, polymer lithium ion battery working principle:

Lithium-ion battery positive electrode generally uses lithium cobalt acid, nickel cobalt manganese lithium, lithium iron phosphate, the negative electrode is graphite, the electrolyte is LiPF6+EC+DMC, and the outer casing is packaged in aluminum plastic film. During charging, lithium ions are separated from the lattice of the positive layered oxide, migrated to the surface of the layered negative electrode by the organic electrolyte, and then embedded in the lattice of the graphite material, while the remaining electrons reach the negative electrode from the external circuit. In contrast, the discharge is reversed and lithium ions are removed from the graphite lattice back into the positive oxide crystal lattice. In the case of normal charge and discharge, the intercalation and extraction of lithium ions between the graphite and the oxide of the layered structure generally only cause a change in the interlayer spacing without causing damage to the crystal structure, accompanied by charge and discharge, and the positive and negative materials are The chemical structure does not change substantially, so the lithium ion battery is an ideal reversible battery in terms of the reversibility of the charge and discharge reaction. The process of lithium ion entering the electrode is called embedding. The process of coming out of the electrode is called detachment. During charging and discharging, the lithium ion is inserted into and out of the positive and negative electrodes of the battery. It is shaken in the positive and negative poles like a rocking chair. Therefore, some people regard the image of a lithium-ion battery as a "rocking chair battery."

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