Energy density comparison
As a battery type, the lithium battery is a closed system. The battery is just a carrier of energy and must be charged in advance to function. density of the electrode material. Since the current energy density of negative electrode materials is much higher than that of positive electrodes, increasing the energy density requires continuous upgrading of positive electrode materials, for example from lead-acid to nickel, and then to lithium batteries. However, lithium is already the metallic element with the smallest atomic weight. In theory, the only cathode material better than lithium ions is pure lithium electrode, but the energy density is actually only a quarter of that of gasoline and its commercialization is extremely difficult. in a few decades there is no hope of a breakthrough. Therefore, improving the densThe energy efficiency of lithium batteries is subject to theoretical bottlenecks, and the space is very limited, at most it can be increased from the current 160 Wh/KG to 300 Wh/KG. 1/120 of that of fuel cells, which we can say is lost on the starting line.
Comparison of volume energy density
The main disadvantage of hydrogen, the raw material of fuel cells, is that the volume energy density is not high. Nowadays, pressurization is mainly used to solve this problem. issue. According to the current pressurization mode of 700 atmospheres, its volumetric energy density is 1/3 that of gasoline. For the same 300 kilometers journey, the volume of the fuel cell hydrogen storage tank is 100 L and the weight is 30 KG. The corresponding fuel tank of a gasoline vehicle is 30 L. However, the volume of the electric motor is 80L smaller than that of a gasoline vehicle. the internal combustion engine, and the total volume is not much different. Lithium battery vehicles are divided into two main technical paths: ternary and lithium iron phosphate. The representative companies are Tesla and BYD. The ternary energy density is higher, but the safety is poor and requires auxiliary safety protection equipment. The two batteries needed to travel 300 kilometers have a volume of 140 L and 220 L and a weight of 0.4 tonnes and 0.6 tonnes, which is a lot. higher than that of fuel cells. In the future, if hydrogen storage alloy and low-temperature liquid hydrogen storage technologies can achieve breakthroughs, the volumetric energy density of fuel cells will increase by 1.5 times and 2 times respectively, and the benefits will be more obvious.
Power density comparison
A fuel cell can essentially be understood as a chemical power generation system using hydrogen as a feedstock, so that the power output is relatively stable in order to maximize discharge. power, a power battery system must be added. For example, the Toyota Mirai is equipped with nickel metal hydride batteries. However, as an open power system, its energy comes from an external supply. The additional nickel-metal hydride battery does not need to consider the issue of energy storage. It only needs 5-8 degrees to meet battery life requirements. are not high. In actual work, there are very few usage restrictions. Although the theoretical discharge efficiency of lithium batteries is very high, there are many restrictions on their use so as not to harm the life of the battery.battery. When fully charged, it cannot be discharged at a high rate, and fast discharge is only applicable in the range of 0-80%. Even so, with a discharge rate of 5C, the battery life in the laboratory will be reduced to only 600 times, and it will be further reduced to 400 times in real working conditions, for example, even if the maximum power of Telsa can do it. reached 310KW, the actual discharge rate is only 4C. In addition, as a closed energy storage system with low energy density, lithium batteries are fundamentally difficult to be compatible with high-power discharge and high battery life unless the weight of the battery is significantly increased. Even though Tesla uses the ternary battery with the best energy density at present, and the weight of its battery components is
Operating principles and usage knowledge oflithium batteries, solar cells and fuel cells
< p>Hydrogen fuel cells are more promising, lithium batteries are polluting, while hydrogen fuel cells generate kinetic energy thanks to the combination of hydrogen and oxygen, which is non-polluting. Lithium batteries and hydrogen fuel cells each have their advantages and disadvantages. In summary, both have their own advantages in terms of charging/refueling times, pollution levels, cruising range, charging station costs and battery costs. For example, hydrogen fuel cells can be recharged in just a few minutes, but lithium batteries typically take more than an hour, even when overcharged. For example, the Tesla V3 Supercharger, although it may have extremely fast charging speed, it does not represent the general situation.ral.
As for the level of pollution and cruising range, it goes without saying that these are the advantages of hydrogen fuel cells. Lithium-ion batteries have always been difficult to break the cruising range bottleneck, and they are also sources of pollution. However, because lithium batteries are more mature, the costs of their charging stations and batteries are much lower than hydrogen fuel cells. According to research, the cost of building one hydrogen refueling station is approximately equal to the cost of building five lithium battery charging stations (excluding subsequent maintenance).
Let me say that these two types of batteries have great prospects, but their future development directions will be different. Lithium batteries are more suitable for passenger cars, while hydrogen fuel cellsHydrogen is more suitable for utility vehicles. In a similar conclusion, Professor Ouyang Minggao of Tsinghua University (Academician of the Chinese Academy of Sciences) mentioned at the 2018 Hydrogen Energy Industry Innovation and Development Forum: "Through various practical, lithium-ion battery systems are more suitable for replacing gasoline engines, and hydrogen fuel cell systems are more suitable for replacing diesel engines. Therefore, current technical research focuses on fuel cell commercial vehicles. "
Whether the energy supply system of future vehicles will carry energy from the battery. or from the battery? Fuel cells generate electricity? We are currently living in an era where fierce battles are being waged around this issue
Currently, the core power system technology at.hydrogen fuel cell is less mature than that of electric vehicles. With the continued advancement of fuel cells and hydrogen storage and other related technologies, fuel cell vehicles. are even less mature than electric vehicles. The field of automobile use could also gradually catch up with electric vehicles and experience development on a larger scale.
Is a hydrogen fuel cell a battery? Maybe you really thought wrong.
Lithium batteries are a type of battery that uses lithium metal or lithium alloy as the negative electrode material and uses a non-aqueous electrolyte solution . Use the following reaction: Li+MnO2=LiMnO2 This reaction is a redox, discharge reaction. Since the chemical properties of lithium metal are very active, the processing, storage and use of lithium metal are sosubjected to very high environmental requirements.
A fuel cell is an electricity production device that directly converts the chemical energy present in fuel and oxidizer into electrical energy. It directly converts the chemical energy of the fuel into electrical energy without going through the combustion process.
Solar cells are made of monocrystalline silicon, polycrystalline silicon, thin-film semiconductors and other materials by diffusion to form a PN junction. Photoelectric PN junctionThe photochemical effect directly converts light energy into electrical energy.
The difference between lithium-ion batteries, supercapacitors and fuel cells
As we all know, pure electric vehicles are a type of energy vehicles new. Batteries used in this field. The models are mainly lithium batteriesm ternary batteries and some are lithium iron phosphate batteries. These two batteries are lithium. In addition to pure electric vehicles, hydrogen fuel cell vehicles are also new energy vehicles. So, is a hydrogen fuel cell a battery?
To answer this question, we first need to understand the difference between hydrogen fuel cells and lithium batteries. A hydrogen fuel cell, as its name suggests, is a device that converts hydrogen and oxygen into electrical energy through a chemical reaction. Its basic principle is actually the reverse reaction of the electrolysis of water, providing hydrogen and oxygen to the anode and cathode, respectively. After the hydrogen diffuses outward through the anode and reacts with the electrolyte, the electrons are released and reach the cathode via an external charge, forming a current.nt electric intended for the vehicle.
For the lithium battery carried in pure electric vehicles, it is an energy storage device. For example, ternary lithium batteries store electrical energy by charging them and release it when needed. The hydrogen fuel cell is a power generation device that converts chemical energy into electrical energy. From this point of view, hydrogen fuel cells cannot be called batteries.
However, compared to hydrogen fuel cells and lithium batteries, each has its own advantages and disadvantages. Hydrogen fuel cells only require a replenishment of hydrogen energy during use and are relatively fast, while lithium batteries are relatively slow to replenish energy. For example, even if a purely electric vehicle is recCharged using a fast charging station, it typically takes around three hours to fully charge.
However, hydrogen energy resupply generally relies on hydrogenation stations, and building hydrogenation bombs is relatively expensive. For example, it would cost around 10 million yuan to build a hydrogen refueling station capable of refueling 200 kilograms of hydrogen. For lithium batteries, the price of building charging piles is relatively cheap. So, for now, the field of new energy vehicles is still dominated by purely electric vehicles, and hydrogen fuel cell vehicles are relatively rare.
This article is from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.
Lithium battery is a kind of battery, and supercapacitorr is a capacitor. The battery and the capacitor are two completely different electronic components, and there is no comparison. A fuel cell is a special type of battery. The energy storage material in a regular battery is stored inside the battery, while the energy storage material in a fuel cell is provided externally. Compared to ordinary batteries, a fuel cell does not need to be. loaded, as long as it is fueled, it can work.