Fuel cell batteries operate on the same electrochemical principle as lithium-ion batteries. However, because fuel cell batteries generate electricity using electrochemical principles, they are more efficient, generally around 60% in automotive applications.
Fuel cell batteries operate in the same way as internal combustion engines, with the fuel being the only energy conversion point. The fuel is stored in tanks, making fuel cell batteries relatively safe. The energy in the fuel cell stack is minimal. Having worked with fuel cell batteries my entire life, I've never witnessed a combustion or explosion. If there's a problem with the fuel cell stack, simply cutting off the hydrogen supply makes it safe. Therefore, fuel cell batteries operate like internal combustion engines, making them safer than lithium-ion batteries.
Fuel cells are used in vehicles to replace internal combustion engines. Currently, fuel cells operate at low voltage and high current, so they are boosted by DC/DC converters to achieve hybrid electric power. This was proposed by Minister Wang Yi and Ouyang, and it is now internationally accepted.
If a range-extended electric vehicle (REEV) is to be developed, the risk of lithium-ion battery explosions cannot be prevented. Hybrid electric vehicles, using supercapacitors or nickel-metal hydride batteries, are a safer option. Compared to internal combustion engines, the fuel tank is replaced by a hydrogen cylinder, and the internal combustion engine is a fuel cell engine, with water as the only emission. Compared to electric vehicles and plug-in hybrid electric vehicles, fuel cell vehicles are suitable for high-power, long-distance transportation, making them ideal for buses and heavy-duty vehicles, where they have a clear advantage.
By 2017, my country had over 2,000 fuel cell vehicles. Yesterday's report stated that the number was expected to exceed 1,500 by 2018, meaning we now have over 2,400 fuel cell vehicles in operation, catching up with the United States. Regarding the international battery situation, on December 15, 2014, Toyota announced the start of sales and the free use of its patents, marking a significant advancement for the development of fuel cell vehicles.
Due to limitations on hydrogen refueling stations for fuel cell passenger vehicles, Toyota partnered with Hino to develop fuel cell buses, intending to use them as commuter vehicles for the Olympics. Recently, Toyota has also begun collaborating with Kenworth in the US to develop heavy-duty vehicles, planning to operate 10 in California. The California Air Resources Board provided $45 million in funding, highlighting a key direction for fuel cell vehicles to replace diesel vehicles.
Honda also developed a fuel cell vehicle in 2016, and Hyundai has ordered approximately 4,000 fuel cell vehicles in Europe. Regarding fuel cell batteries, their lifespan has largely met requirements; 13 vehicles in California and Oakland have already achieved 25,000 hours of operation. In terms of battery consumption, the international standard is 0.2 grams per kilowatt, while the domestic standard is around 0.4 grams. Europe has also conducted a second demonstration run on buses.
At the same time, consideration began to be given to establishing a production line for fuel cell stacks.
Internationally, fuel cell vehicles have entered the market introduction stage. Engine power has increased significantly, and vehicles using 70MPa gas cylinders can now travel over 500 kilometers and operate at temperatures below -30 degrees Celsius, basically meeting the requirements. The current issues are the lack of large-scale production lines, relatively high costs, and constraints imposed by hydrogen refueling stations. Therefore, from the perspective of fuel cell stacks and fuel cell technology, the most important task for the future is to reduce the amount of proton pumps (PTs) used and lower the cost of catalytic converters for fuel cell vehicles. Domestically, from the 2007 Shanghai Bibiden Race to the 2010 World Expo, we conducted extensive testing of fuel cell vehicles. After the World Expo, SAIC launched the Innovation Journey, demonstrating that electric vehicles are suitable for my country's range-extended electric vehicle environment.
This year, we established the Hydrogen Energy and Fuel Cell Power Battery Alliance, and held its first forum in Haikou in October. From a national perspective, we have already allocated 827 million yuan in funding during the 13th Five-Year Plan period for two major projects: one is the technical research and engineering development of low-cost fuel cell stacks and key materials, undertaken by Dalian Xinyuan Power, and the other is a project undertaken by Weichai. These two projects have received substantial funding.
Currently, the country has 57 companies and 86 models selected in 2018, including 23 models from Yihuatong and 20 models from Guangdong Guohong. We had over 1500 vehicles in 2018. Various cities and provinces have mobilized, with Shanghai leading the way. Shanghai plans to have 400-500 commercial vehicles for demonstration operation, establishing three platforms: a power system and component R&D platform, a hydrogen energy industry public service platform, and a fuel cell vehicle operation and maintenance center. The Shanghai Maxus V80 is the fourth light passenger vehicle in the world that can be publicly sold, priced at 300,000 yuan. Xinbin County in Liaoning Province purchased 60 vehicles and has already begun demonstration operation, with a post-subsidy price of 300,000 yuan. SAIC has also developed the Roewe 950, which can also be publicly sold. Yihuatong, in cooperation with Shenli, has developed three types of fuel cell engines, ranging from 30 kW to 60 kW, all of which are being installed in vehicles for demonstration operation.
The demonstration operation in Zhangjiakou involves 74 fuel cell vehicles, 99 Foton vehicles, and 25 Yutong 12-meter buses. The demonstration operation has already begun. Zhangjiakou is a relatively cold region in my country. The results show that, under cold conditions, fuel cell vehicles are superior to lithium-ion battery vehicles once the starting problem is solved. This is because once a fuel cell vehicle is running, its operating temperature is the set operating temperature, unlike lithium-ion batteries which are more susceptible to environmental influences.
Yutong has developed three generations of fuel cell vehicles. The most important proof is that under air-conditioning conditions, it consumes about 0.8 kg of hydrogen per 100 kilometers. Demonstration operation has begun in Zhengzhou, in addition to Zhangjiakou. Our company, Guohong, can already produce 30 kW and 80 kW fuel cell stacks. This is the P30, and this is the 85 kW stack, suitable for buses. 70 fuel cell vehicles are in operation in Yunfu City, and the first light rail vehicle has rolled off the production line in Foshan. Now Germany is developing light rail transport vehicles, which is a very good direction for development.
Currently, there are about 10 hydrogen refueling stations in operation in my country, and it is expected that there will be around 100 next year. Some people say there are 40, but yesterday I heard a report that 12 are actually in operation. The stations with the most frequent operation are Zhangjiakou, Yunfu and Shanghai, which have the highest hydrogen refueling volume.
These are some older hydrogen refueling stations, capable of conducting various hydrogen refueling experiments. There's the hydrogen refueling station built by Xinyuan Power with support from the Dalian 863 Program, and another one built by Yutong itself. The largest hydrogen refueling station is being built by Shenhua in Rugao, with a daily refueling capacity of 1,000 kilograms.
At the 2017 Shanghai Science and Technology Association Annual Meeting on Future Mobility, Wan Gang pointed out that hydrogen fuel cell power batteries have basically met the requirements for vehicle use in terms of lifespan, reliability, and applicability. my country has initially mastered the relevant core technologies and has basically established a fuel cell power system technology platform with independent intellectual property rights. In the future, it is important to strengthen collaborative innovation and accelerate the comprehensive development of the fuel cell power battery industry.
Domestically, we have mastered the core technologies of fuel cell power batteries and accumulated rich experience through extensive demonstration operations, thus possessing the conditions for large-scale demonstration operations. Our current focus is on rapidly achieving mass production of key materials, electrocatalysts, proton exchange membranes, membrane electrode assemblies (MEAs), and bipolar plates, laying the foundation for reducing stack costs and improving stack consistency. We aim to increase the specific power of the stack, reduce stack costs and PtA usage, and further improve the reliability and durability of the stack system.
Internationally, fuel cell vehicles have reached the size of four-cylinder internal combustion engines. At the last Haikou conference, Honda announced that it had reached the level of a six-cylinder internal combustion engine, with a power density of 3 kilowatts per liter. The fuel cell stacks used in domestically produced vehicles are currently around 2.0 kilowatts per liter, which is the level used in the V80, Roewe 750, and Roewe 950. Therefore, our fuel cell stacks have an output power that is about one-third lower than those abroad.
To reduce the cost of our fuel cell engines, especially the cost of the stack, we need to improve the individual cells. The first step is to study how to increase the specific power of the individual cells, which involves reducing chemical polarization, ohmic polarization, and mass transfer polarization.
To reduce chemical polarization, it is crucial to develop highly efficient electrocatalysts. Currently, the internationally accepted approach is to use platinum alloy catalysts. There are three methods for preparing core-shell catalysts. This is an ultra-small platinum-copper alloy catalyst developed by our institute; its performance is 35 times that of current carbon-platinum catalysts. This is a platinum-nickel nanowire catalyst developed by our institute, and its performance is more than three times that of carbon-platinum catalysts. With highly efficient electrocatalysts, we can increase the current density of the fuel cell stack and reduce chemical polarization. Simultaneously, we need to use platinum-reinforced hybrid films to reduce ohmic polarization. Strengthening the film reduces polarization, and using peroxides reduces chemical corrosion of the film. These are the results of our institute's work; its F release rate is significantly reduced.
This is a 1015-micron membrane made by Gore. I can reduce ohmic polarization by using thin films. Additionally, we need to adopt new flow fields to reduce mass transfer polarization. For example, Toyota, by changing a two-dimensional flow field to a three-dimensional flow field, significantly reduced mass transfer polarization, allowing us to increase the current density to several amperes per square centimeter. This is because they changed their original two-dimensional flow field to a three-dimensional flow field, achieving a current density of several amperes per square centimeter.
With the improved performance of single-cell reactors, domestic laboratory research on single-cell reactors has achieved above 0.7V at 1 ampere per square centimeter and above 0.6V at 2 amperes per square centimeter. We are now moving towards 2.5 amperes. Dual-cell reactors may achieve 1 ampere per cubic centimeter, and we aim to develop to 2 or 2.5 amperes in the future. In this way, our reactor stack technology can reach or even surpass Toyota's level.
From the perspective of the fuel cell stack, higher flow field resistance leads to better stack consistency, but it also increases the air supply force and adds internal losses to the air compressor. We need to research air compressors with low internal losses to ensure high power density output of our fuel cell stacks. Additionally, we need to improve the consistency of bipolar plate fabrication, especially flatness. Whether it's a metal plate or a graphite plate, flatness is a key factor determining stack consistency. We need to improve the consistency of MEA fabrication, particularly MEA flatness and sealing technology. After the fuel cell is assembled, the membrane expands in the common channels, severely affecting airflow distribution. Therefore, all exposed membrane in the common channels must be sealed to ensure that the assembly resistance remains unchanged during operation. Thus, the core of MEA fabrication is using thin films and solving sealing technology. Furthermore, we need to optimize the stack structure.
This is the bipolar plate used domestically. Initially, it was made of non-porous carbon plates, membrane-pressed plates, or expanded graphite plates, all of which belong to this category. There are also composite plates. Currently, Xinyuan mainly uses composite plates, which use metal for partitioning, such as 0.1 mm stainless steel plates, and carbon plates for flow field. Now, the development is towards metal plates.
Metal plates can increase the power density of fuel cell stacks. These are metal bipolar plates made of chemical compounds, which basically meet our usage requirements.
From the perspective of electrode preparation, there are now three generations. Initially, they were used for spray-painted motors, then CCM, and now the fuel cell stacks used in installations mainly use second-generation electrodes. We also need to overcome the mass production technology of second-generation electrodes because the current spray-painting technology is not suitable for the production of millions of vehicles.
This is the electrostatic spraying technology developed by the Institute of Chemical Physics.
The assembly process of fuel cell stacks needs to be improved because fuel cell stacks are assembled using a press. The key components are bipolar plates, MEA, and seals. Therefore, this assembly requires strict process and positioning technology.
This was developed by us in alkaline batteries. Because the sealing and MEA compression need to be effectively coordinated, and all components need to be consistent and have a fixed height, after I designed this stack, I knew what the final assembly height should be. With this formula, a uniform stack can be assembled.
This is a 3.0 kW/liter fuel cell stack that we assembled at our Institute of Chemistry. Currently, our operating current density is 1 ampere, and we hope to increase it to 1.5 and 2 amperes as soon as possible.
This is its improved version, which has already reached 400 watts per kilogram and 1 ampere per square centimeter, and is now being improved to 2 amperes. If we can now achieve 2 amperes per square centimeter, our PT usage will be the same as Toyota's international level, at 0.2 grams per kilowatt, while currently we are still around 0.4 grams. Our volumetric power density may reach more than 300 kilowatts per liter, which will bring us closer to the international level. Therefore, I hope that everyone involved in fuel cell technology will unite to quickly increase the operating current density and specific power of our country's fuel cell technology. If you are using graphite plates, the volumetric power density may be lower, but you also need to increase the current density. When the current density is increased, the PT usage will decrease. Because fuel cell technology is sold by kilowatt, not by the cost of the entire stack, increasing the current density and the kilowatt output of the stack will be much higher. For example, if it originally output 30 kilowatts, it can now output 50 kilowatts, thus significantly reducing my costs.
What I mean is that whether it's the mainstream domestic manufacturers producing graphite plates or those producing metal plates, we all need to increase the operating current density of the fuel cell stack to catch up with international standards; the two are essentially the same. Some people say that graphite plates don't need improvement, because future costs will squeeze us out. So I say that graphite plates also need improvement. We need to improve the consistency and uniformity of the MEA and the battery, and improve the assembly process. Once our fuel cell stack improves, the system needs to coordinate accordingly.
I think that fuel cell batteries are basically not ceramic now, but at least they are plastic, not steel. So the system plays a protective role, allowing them to survive in a suitable environment so that the lifespan of the fuel cell battery can meet the requirements.
With advancements in key materials, our protective measures can gradually be reduced, but not yet. For example, if our electrocatalysts could withstand 1.6V high voltage without oxidation, and the carbon support also remained unoxidized, then there would be no need to address open-circuit oxidation during startup and shutdown. Therefore, our materials are currently lagging behind, and even internationally, this hasn't been achieved. The lifespan of our fuel cell power batteries is the result of cooperation between the stack and the system, not just the stack's own efforts; both must be combined. Therefore, we must strengthen the research and development of key components in both the stack and the system. Therefore, I suggest:
First, we need to quickly improve the industrial chain of fuel cell batteries and establish a production line for carbon paper diffusion layers. Many people say that our industrial chain is basically complete, but I believe that we absolutely need to establish production lines for small components like carbon paper diffusion layers, which we don't have yet. Currently, we are focusing our attention on membranes and bipolar plates. Additionally, we need to develop air compressors and hydrogen circulation pumps.
Secondly, it is necessary to increase the operating current density of the fuel cell stack, improve its volumetric power-to-weight ratio, and reduce its cost, thus laying the foundation for the development of passenger vehicles. This is because passenger vehicles generally aim to place the fuel cell stack and control system at the front of the internal combustion engine.
Third, we need to conduct in-depth research on the degradation mechanism of fuel cell stacks and develop new corrosion-resistant and stable materials to significantly improve the reliability and durability of engines. Therefore, reliability and durability are determined by both the system and the fuel cell stack. If the fuel cell stack improves, we can simplify the system. Thus, the fuel cell stack and the system must work together to simplify the fuel cell stack system through advancements in key materials.
Fourth, we will conduct theoretical and applied research on ultra-low platinum and non-platinum electrocatalysts to further reduce the platinum content in batteries to less than 0.1 grams per kilowatt. This is a basic requirement for fuel cell power batteries internationally.
Fifth, we need to establish testing and rapid durability evaluation methods for key components, fuel cell stacks, and battery systems. This is something our fuel cell standards committee is currently working on. Everyone claims to be at the forefront, but to determine if we are truly number one, we need a neutral body to conduct the evaluation. Therefore, I think we should establish a neutral testing organization as soon as possible—one that doesn't develop fuel cell systems or stacks, but focuses on testing. This would be of great use in advancing our fuel cell technology and catching up with world-class standards.
I hope that our fuel cell vehicles can quickly reach the upward phase of the S-curve of commercialization, and at a certain point we can get rid of subsidies and become profitable. Some people predict that, in terms of key materials, fuel cell vehicles may be cheaper than lithium-ion batteries if the amount of platinum used is reduced, because only platinum is expensive. So if you can reduce the cost of platinum, the other components are steel and organic materials, which can completely reduce costs. Therefore, we have the foundation to compete with lithium-ion batteries and gasoline vehicles, but it depends on the joint efforts of our technical personnel.
