What is a power battery? What is the difference between power battery and ordinary battery?
Battery technology is a great invention with a wonderful and long history. The English "Battery" of 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 the electrolyte to solve the battery polarization problem and produced the first non-polarized zinc-copper battery that can maintain a balanced current, also known as the "Daniel battery."
In 1860, France's Plante invented a battery with lead as the electrode, which was also the predecessor of a storage battery; at the same time, France's Recrans invented the carbon-zinc battery, bringing battery technology to the field of dry batteries.
The commercial use of battery technology began with dry batteries. It was invented by the British Hellerson in 1887 and mass-produced in the United States in 1896. At the same time, Thomas Edison invented the rechargeable iron-nickel battery in 1890, which was also realized in 1910. Commercialized mass production.
Since then, thanks to commercialization, battery technology ushered in an era of rapid advancement. Thomas Edison invented alkaline batteries in 1914, Schlecht and Akermann invented sintered plates for nickel-cadmium batteries 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 was affected by the energy crisis and gradually developed in the direction of physical power. In addition to the continuous advancement of solar cell technology that appeared in 1954, lithium batteries and nickel-metal hydride batteries were gradually invented and commercialized.
What is a power battery? The difference between it and ordinary batteries
The power source of new energy vehicles is generally mainly based on power batteries. The power battery is actually a kind of power source that provides the power source for transportation. The main differences between it and ordinary batteries are:
1. Different in nature
Power battery refers to the battery that provides power for transportation, generally relative to the small battery that provides energy for portable electronic equipment; while ordinary battery is a kind of lithium metal or lithium alloy as the negative electrode material, using non-aqueous electrolyte solution The primary battery is different from the rechargeable lithium ion battery and the lithium ion polymer battery.
Two, the battery capacity is different
In the case of new batteries, use a discharge meter to test the battery capacity. Generally, the capacity of power batteries is about 1000-1500mAh; while the capacity of ordinary batteries is above 2000mAh, and some can reach 3400mAh.
Three, the discharge power is different
A 4200mAh power battery can discharge the power in just a few minutes, but ordinary batteries can't do it at all, so the discharge capacity of ordinary batteries is completely incomparable with power batteries. The biggest difference between a power battery and an ordinary battery is its large discharge power and high specific energy. Since the power battery is mainly used for vehicle energy supply, it has a higher discharge power than ordinary batteries.
Four, 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 the emerging lithium-ion power battery, which are divided into power-type power batteries (hybrid vehicles) and energy-type power batteries (Pure electric vehicles); Lithium batteries used in consumer electronic 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.
The current main types of power batteries
Lead-acid battery technology, nickel-hydrogen battery technology, fuel cell technology, and lithium battery technology are still the main mainstream technologies on the market.
Lead-acid batteries
Lead-acid battery has the longest application history and the most mature technology. It is the battery with the lowest cost and price, and it has achieved mass production. Among them, the valve-regulated sealed lead-acid battery (VRLA) once became an important vehicle power battery, which was used in the EV and HEV developed by many European and American automobile companies, such as the Saturn and EVI developed by GM in the 1980s and 1990s, respectively. Electric cars, etc.
However, lead-acid batteries have low specific energy, short battery life, high self-discharge rate, and low cycle life; their main raw material lead is heavy, and heavy metal environmental pollution may occur during production and recycling. Therefore, at present, lead-acid batteries are mainly used for ignition devices when cars are started, and small equipment such as electric bicycles.
NiMH batteries
Ni/MH batteries have good resistance to overcharge and overdischarge. There is no heavy metal pollution problem, and there will be no electrolyte increase or decrease during the working process, which can achieve a sealed design and maintenance-free. Compared with lead-acid batteries and nickel-cadmium batteries, nickel-hydrogen batteries have higher specific energy, specific power and cycle life.
The disadvantage is that the battery has a poor memory effect, and with the progress of the charge and discharge cycle, the hydrogen storage alloy gradually loses its catalytic ability, and the internal pressure of the battery will gradually increase, which affects the use of the battery. In addition, the expensive price of nickel metal also leads to higher costs.
In terms of key materials, nickel-metal hydride batteries are mainly composed of positive electrode, negative electrode, separator and electrolyte. The positive electrode is nickel electrode (Ni(OH)2); the negative electrode generally uses metal hydride (MH); the electrolyte is mainly liquid, and the main component is hydrogen. Potassium oxide (KOH). At present, the research focus of nickel-hydrogen battery is mainly on the positive and negative electrode materials, and its technology research and development is relatively mature.
Ni-MH batteries for vehicles have been mass-produced and used, and they are the most widely used type of vehicle batteries in the development of hybrid vehicles. The most typical representative is the Toyota Prius, which is currently the largest mass-produced hybrid vehicle. PEVE, a joint venture between Toyota and Panasonic, is currently the world's largest manufacturer of nickel-hydrogen power batteries.
Now that nickel-metal hydride batteries have withdrawn from the ranks of mainstream power batteries, why does Toyota stick to the nickel-metal hydride battery camp?
This has to be said that the biggest advantage of Ni-MH batteries: super durability!
Once the famous American automobile media conducted a comparative test on a first-generation Prius that had been used for ten years. The test results show that after 10 years of driving 330,000 kilometers for the first-generation Prius model with nickel-metal hydride batteries, comparing it with the data of the new car, both fuel consumption performance and power performance remain at the same level. The hybrid system and the Ni-MH battery pack are still working normally.
In addition, even after running 330,000 kilometers in ten years of use, this first-generation Prius has never had any problems with its nickel-metal hydride battery pack. Ten years ago, people questioned the situation that the degradation of battery capacity would greatly affect fuel consumption and power performance. It didn't show up either. From this point of view, the Japanese who have always been rigorous and conservative do have their own unique reasons for their love for nickel-hydrogen batteries.
The fuel cell
Fuel cell is a power generation device that directly converts chemical energy in fuel and oxidant into electrical energy. Fuel and air are fed into the fuel cell separately, and electricity is produced. From the outside, it has positive and negative electrodes and electrolytes, etc., like a battery, but in fact it cannot "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 they are usually restricted to industrial applications such as power plants and forklifts. The basic principle of a hydrogen fuel cell is the reverse reaction of the electrolysis of water. Hydrogen and oxygen are supplied to the anode and the cathode respectively. After the hydrogen diffuses out through the anode and reacts with the electrolyte, electrons are released to the cathode through an external load.
The working principle of a hydrogen fuel cell is: sending 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 cathode plate (positive electrode) of the fuel cell, and electrons cannot pass through the proton exchange membrane. This electron can only pass through the external circuit to reach the cathode plate of the fuel cell, thereby generating current in the external circuit.
After the electrons reach the cathode plate, they 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, electric energy can be continuously supplied.
The electricity generated by the fuel cell is supplied to the electric motor through inverters, controllers and other devices, and then the wheels are driven to rotate through the transmission system, drive axle, etc., so that the vehicle can drive on the road. Compared with traditional vehicles, 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, nor does it emit sulfur and particulates. Therefore, hydrogen fuel cell vehicles are truly zero-emission and zero-pollution vehicles, and hydrogen fuel is the perfect vehicle energy source!
