Lithium battery vs hydrogen fuel cell
view one
Elon Musk: Hydrogen fuel cells are "incredibly stupid"!
As early as 2015, he claimed: "If you want to choose an energy storage mechanism, you should choose methane or propane, because they are easier to produce." Musk said: "I just think (hydrogen fuel cell) is very stupid... .... It is very difficult to make hydrogen, store it and use it in a car.", "If you take a solar panel to directly charge the battery pack, compared with electrolysis, hydrogen is taken, oxygen is separated, and hydrogen is compressed... .. This is about half of its efficiency."
In fact, Musk's words are not unreasonable. Compared with batteries, the energy conversion efficiency of hydrogen fuel cells is always lower than that of batteries. Compared with Tesla’s BEV efficiency, the best FCV currently on the market is still less than half of the BEV in efficiency; in addition, the development of the industrial chain In terms of infrastructure (hydrogen refueling station) construction, the gap between hydrogen fuel cells and lithium batteries is still decades away.
The development of fuel cells continues, but the charging infrastructure, the mass production of hydrogen, and its inventory are lagging behind. The use of hydrogen requires a lot of infrastructure construction, high quality, and large pressure accumulators. The production of fuel cells, pressure tanks (carbon fiber), the price of hydrogen for refueling, the infrastructure of hydrogen refueling stations, and the construction of H2 production facilities are all too expensive. In addition, at present, thermochemical processes using fossil energy as raw materials are widely used in industry, mainly including hydrogen production methods such as hydrocarbon steam reforming, heavy oil partial oxidation, coal gasification, and water electrolysis. In the mainstream hydrogen production process, there are also problems of pollution and low efficiency.
View Two:
"The future market belongs to fuel cells"
For many years, Toyota has been betting hydrogen fuel cells on battery electric vehicles to achieve its zero-emission vehicle strategy. Toyota's fuel hydrogen battery is an advanced technology used by Toyota in Mirai's new energy vehicles. Toyota hydrogen fuel cell is like a power station. It produces electricity through the chemical reaction of oxygen and hydrogen. It does not need to be charged like ordinary storage batteries. Only need to add hydrogen to produce electricity through chemical reactions.
The battery life advantage of the hydrogen fuel cells is also obvious compared with lithium batteries. It also has a battery life of 500 kilometers. It takes a long time for an ordinary lithium battery to charge, super fast charge also takes one and a half hours, and hydrogen dye battery can be filled with hydrogen in only 3 minutes. . In addition, hydrogen far surpasses lithium-ion in energy density, and the two are not even on the same order of magnitude.
Hydrogen fuel cell vehicles also have the following advantages:
1. Hydrogenation is like refueling, usually only 3~5 minutes. The charging of electric vehicles is a slow process. Even if Tesla launches a supercharging station, it usually takes more than an hour.
2. The main component of a hydrogen fuel cell is hydrogen. We know that the chemical formula of water is oxygen dihydrogen. The hydrogen fuel cell will not pollute the environment after the end of its service life. Lithium-ion batteries contain a lot of heavy metals. If they are not recycled properly, they will cause greater pollution to the environment.
3. Hydrogen fuel cells have high energy storage density, lightweight, and generally longer cruising range. Usually, more than 500 kilometers and pure electric vehicles are based on the size of the battery capacity. At present, most pure electric vehicles have a cruising range of about 300 kilometers, and a few models can reach 400 to 500 kilometers.
Fuel cell vs lithium-ion battery
Currently, the global energy and environmental systems are facing huge challenges. Among them, the automobile industry, which is a major consumer of oil and carbon dioxide, is also facing a revolutionary change. The use of pure electric drive including pure electric and fuel cell technology as the main technical direction of new energy vehicles has become the world Consensus formed by various countries. Fuel cell vehicles are another important direction of electric vehicle batteries. Compared with lithium-ion batteries, it can be clearly seen that there are obvious advantages and disadvantages between the two.
First of all, it is from the perspective of security.
Safety hazards of fuel cells: Leakage and control of hydrogen is the main source of safety hazards in fuel cell systems, which belong to the physical level, while the safety hazards of lithium-ion batteries mainly come from chain reactions that are not easy to control, which belong to the chemical level. Because the chain reaction speed is extremely short. In terms of controllability, the control difficulty of lithium-ion batteries is higher than that of fuel cells. However, in the case of extreme violent collisions, the degree of harm to fuel cells is even greater. Of course, this is only in theory. The hydrogen itself has a short leakage time due to its fast escape. In addition, the high-pressure hydrogen cylinder is resistant to impacts, drops, gunshots, and other unconventional properties that also provide security.
Secondly, from the perspective of low-temperature performance.
Because the viscosity of the electrolyte increases at low temperatures, the conductivity decreases, which will lead to a sharp increase in the internal polarization of the battery. Generally, manufacturers do not recommend sub-zero discharge behavior. Therefore, lithium batteries need external heating to solve the low-temperature problem. The low-temperature start performance of the fuel cell is poor, but with the increase of its own heat release after startup, the temperature of the stack will quickly stabilize in the normal operating temperature range of 80-90°C. However, how to achieve low-temperature startup of fuel cells, especially low-temperature startup under the premise of not using external auxiliary power, is an important research topic.
Third, it is from the perspective of cost.
On the whole, whether it is a fuel cell or a lithium-ion battery, the price is higher than that of traditional energy sources. In particular, the complexity and harsh conditions of the source, storage, and safe use of hydrogen have resulted in high costs for hydrogen fuel cells, making it difficult to gain advantages in the short term. Judging from the mass production data, the cost of fuel cells is still very high, and it is expected that the price of internal combustion engines may be close to the current price of internal combustion engines under the premise of long-term mass realization.
Fourth, the time it takes to charge.
Long charging time is always an indelible pain point for lithium-ion batteries. In the normal charging mode, a car equipped with a lithium-ion battery takes 3 to 8 hours to fully charge. In contrast, fuel cells are much more convenient and fast. Taking hydrogen fuel cells as an example, it only takes 3 to 5 minutes to directly add hydrogen to resurrect with full blood.
Fifth, the cruising range.
This may be the biggest pain point for pure electric vehicles, especially lithium-ion battery vehicles. It is difficult for traditional lithium-ion batteries to exceed 500km in endurance. In contrast, fuel cells with high energy density and lighter weight can reach farther in endurance.
Sixth: Temperature influence.
Fuel cell vehicles can maintain the same long cruising range as in summer through the integrated thermal management of the entire vehicle. This is something that lithium-ion batteries cannot do. Lithium-ion batteries consume power regardless of whether it is PTC heating or air conditioning heating. The fuel cell consumes electricity to power the air conditioner in the summer, while in the winter it only uses waste heat to keep the passenger compartment warm. So theoretically, the mileage in winter should be longer than in summer. At present, there are institutions that are carrying out research on waste heat power generation based on the Rankine cycle. If it can be realized, it will further improve the efficiency of fuel cells.
Seventh: Cost balance.
Fuel cell and pure electric vehicles have different cost balance points. Passenger cars are about 500 kilometers away, and commercial vehicles are about 100 kilometers
Reference:
1].https://www.fz-juelich.de/portal/DE/Forschung/EnergieUmwelt/energiewende.html
[2].https://www.chemie.de/news/1153224/batterie-oder-brennstoffzelle.html
This is a good summary of the relative advantages of batteries and fuel cells as energy sources for automobiles. This is a topic of considerable interest to everyone since the industry is turning almost completely to electric vehicles over the next few years. Your title is straightforward and appropriate. Opening with Elon Musk and his provocative statement is effective and engaging. The use of the two views format is also effective. It reads like a debate and clarifies the various points in favor of the two technologies. Your English is generally quite good, remarkably so. There are some difficulties in a few places. The first sentence in the section headed "The future market belongs to fuel cells" is confusing. I would rewrite it as "For many years Toyota has been betting on hydrogen fuel cells in electrical vehicles to achieve its zero emissions strategy." There is some repetition in your points making the post a little long for a typical blog reader. Your sources seem to be from Chinese web sites that in turn cite German sources. Although I don't know much about these sources, I think it is great to get some international material in the blog. It is perhaps worth noting that both technologies are advancing quite rapidly. Perhaps that's why one source says the fuel cells have only half the efficiency of batteries and another say fuel cells are 60% efficient and batteries are 80% efficient. The difference may also result from different definitions of efficiency. Your figure makes the definitions used in your cited source quite clear. Development of both technologies are going to be interesting to watch over the next few years. And, of course, chemistry plays a central role in both technologies. The post therefore provides good support for the importance and usefulness of chemistry and chemists. Solid effort.
ReplyDelete