What is a power battery? The difference between it and ordinary battery
Battery technology is a great invention with a wonderful and long history. The battery English "Battery" first appeared in 1749. It was first used by American inventor Benjamin Franklin when he used a series of capacitors to conduct electrical experiments. . He used dilute sulfuric acid as an electrolyte to solve the problem of battery polarization, and produced the first non-polarized zinc-copper battery that can maintain a balanced current, also known as "Daniel battery".
In 1860, French Plante invented a battery using lead as an electrode, which was also the precursor of the battery; at the same time, France's Rexroth invented the carbon zinc battery, which made the battery technology move to the field of dry batteries.
Commercial use of battery technology began with dry batteries. It was invented by British Hellerson in 1887 and mass-produced in the United States in 1896. At the same time, Thomas Edison invented a rechargeable iron-nickel battery in 1890, which was also realized in 1910. Commercial mass production.
Since then, thanks to commercialization, battery technology has ushered in an era of rapid development. Thomas Edison invented alkaline batteries in 1914, Schlecht and Akermann invented sintered nickel-cadmium battery plates in 1934, and Neumann developed sealed nickel in 1947 Cadmium batteries, Lew Urry (Energizer) developed small alkaline batteries in 1949, ushering in the era of alkaline batteries.
After entering the 1970s, battery technology has gradually developed toward the physical power source due to the impact of the energy crisis. In addition to the continuous progress of solar cell technology that appeared in 1954, lithium batteries and nickel-hydrogen batteries have also been gradually invented and commercialized.
What is a power battery? It is different from ordinary batteries
The power source of new energy vehicles is generally mainly based on power batteries. A power battery is actually a kind of power source that provides a source of power for transportation vehicles. The main differences between it and ordinary batteries are:
1. Different nature
Power battery refers to a battery that provides power for transportation vehicles, and is generally relative to a small battery that provides energy for portable electronic devices; while a common battery is a lithium metal or lithium alloy as a negative electrode material, using a non-aqueous electrolyte solution The primary battery is different from the Rechargeable battery
lithium ion and lithium ion polymer battery.
2. The battery capacity is different
In the case of new batteries, use a disCharger
to test the battery capacity. The capacity of general power batteries is about 1000-1500mAh; while the capacity of ordinary batteries is above 2000mAh, and some can reach 3400mAh.
3. Different discharge power
A 4200mAh power battery can discharge the power in just a few minutes, but the ordinary battery can't do it at all, so the discharge capacity of the ordinary battery can not be compared with the power battery. The biggest difference between power batteries and ordinary batteries is that their discharge power is large and their specific energy is high. Since the main purpose of the power battery is to provide energy for vehicles, it has a higher discharge power than ordinary batteries.
4. Different applications
The batteries that provide driving power for electric vehicles are called power batteries, including traditional lead-acid batteries, nickel-metal hydride batteries, and emerging lithium-ion power lithium batteries, which are divided into power-type power batteries (hybrid vehicles) and energy-type power batteries. (Pure electric vehicles); lithium batteries used in consumer electronics products such as mobile phones and notebook computers are generally collectively referred to as lithium batteries to distinguish them from power batteries used in electric vehicles.
Main types of power batteries
At present, the mainstream technologies in the market are still mainly lead-acid battery technology, nickel-hydrogen battery technology, fuel cell technology, and lithium battery technology.
The application history of lead-acid batteries is the longest and the technology is the most mature. It is the battery with the lowest cost and the lowest price, and has achieved mass production. Among them, valve-regulated sealed lead-acid batteries (VRLA) once became important automotive power batteries, which are used in EVs and HEVs developed by many European and American automobile companies, such as GM's Saturn and EVI developed in the 1980s and 1990s, respectively. Electric vehicles, etc.
However, lead-acid batteries have low specific energy, short battery life, high self-discharge rate, and low cycle life; their main raw materials are heavy in weight, and may produce heavy metal environmental pollution during production and recycling. Therefore, at present, lead-acid batteries are mainly used for ignition devices when starting cars, and small equipment such as electric bicycles.
Nickel-metal hydride (Ni/MH) batteries have good resistance to overcharging and over-discharging, there is no problem of heavy metal pollution, and there will be no increase or decrease in electrolyte during work, which can achieve a sealed design and maintenance-free. Compared with lead-acid batteries and nickel-cadmium batteries, nickel-metal hydride batteries have higher specific energy, specific power and cycle life.
The disadvantage is that the battery has a poor memory effect, and as the charge and discharge cycle progresses, the hydrogen storage alloy gradually loses its catalytic ability, and the internal pressure of the battery will gradually increase, affecting the use of the battery. In addition, the high price of nickel metal also leads to higher costs.
In terms of key materials, nickel-metal hydride batteries are mainly composed of a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode is a nickel electrode (Ni(OH)2); the negative electrode generally uses metal hydride (MH); the electrolyte is mainly a liquid, and the main component is hydrogen Potassium oxide (KOH). At present, the research focus of nickel-metal hydride batteries is mainly on positive and negative electrode materials, and its technology research and development is relatively mature.
Automotive nickel-metal hydride batteries have achieved mass production and use, and are the most widely used vehicle battery type in the development of hybrid vehicles. The most typical representative is the Toyota Prius, which currently has the largest mass production of hybrid vehicles. PEVE, a joint venture between Toyota and Panasonic, is currently the world's largest manufacturer of nickel-metal hydride batteries.
Now that the nickel-metal hydride battery has withdrawn from the mainstream power battery at this stage, why would Toyota still insist on its camp of nickel-metal hydride batteries?
This has to talk about the biggest advantage of nickel-metal hydride batteries: super durability!
Once the famous American automobile media conducted a comparative test on a first-generation Prius after ten years of use. The test results show that the first-generation Prius model using nickel-metal hydride batteries compared with the data of the new car after 10 years of driving 330,000 kilometers, both in fuel consumption performance and power performance are kept at the same level, indicating The hybrid system and the nickel-metal hydride battery still work normally.
In addition, even after running for 330,000 kilometers in ten years, this first-generation Prius has never experienced problems with its nickel-metal hydride battery pack. People questioned ten years ago that the decline in battery capacity will greatly affect fuel consumption and power performance. Did not appear. From this point of view, the Japanese who have always been rigorous and conservative do indeed have unique reasons for their love for nickel-metal hydride batteries.
The fuel cell
A fuel cell is a power generation device that directly converts the chemical energy present in fuel and oxidant into electrical energy. Fuel and air are fed into the fuel cell separately, and electricity is produced. From the appearance, it has positive and negative electrodes and electrolyte, like a storage battery, but in essence it can not "storage" but a "power plant".
Compared with ordinary chemical batteries, fuel cells can supplement fuel, usually hydrogen. Some fuel cells can use methane and gasoline as fuel, but it is usually limited to industrial fields such as power plants and forklifts. The basic principle of a hydrogen fuel cell is the reverse reaction of electrolyzed water, which supplies hydrogen and oxygen to the anode and cathode respectively. After hydrogen diffuses outward through the anode and the electrolyte reacts, it emits electrons to the cathode through an external load.
The working principle of a hydrogen fuel cell is to send hydrogen gas to the anode plate (negative electrode) of the fuel cell. After the action of the catalyst (platinum), an electron in the hydrogen atom is separated, and the hydrogen ion (proton) that has lost the electron passes through the proton The exchange membrane reaches the fuel cell cathode plate (positive electrode), and electrons cannot pass through the proton exchange membrane. This electron can only reach the fuel cell cathode plate through an external circuit, thereby generating current in the external circuit.
After reaching the cathode plate, the electrons recombine with oxygen atoms and hydrogen ions to form water. Since the oxygen supplied to the cathode plate can be obtained from the air, as long as the anode plate is continuously supplied with hydrogen, the cathode plate is supplied with air, and the water vapor is taken away in time, electricity can be continuously provided.
The electricity generated by the fuel cell supplies power to the motor through inverters, controllers, and other devices, and then drives the wheels to rotate through the transmission system, drive axle, etc., so that the vehicle can be driven on the road. Compared with traditional cars, the energy conversion efficiency of fuel cell vehicles is as high as 60 to 80%, which is 2 to 3 times that of internal combustion engines.
The fuel of the fuel cell is hydrogen and oxygen, and the product is clean water. It does not produce carbon monoxide and carbon dioxide by itself, nor does it emit sulfur and particles. Therefore, hydrogen fuel cell vehicles are truly zero-emission and zero-pollution vehicles, and hydrogen fuel is the perfect vehicle energy!
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