In recent years, in the context of global carbon reduction, the green development path of the shipping industry has gradually pointed to new energy ships, and the development of low-carbon and zero-carbon emission ships has become a trend. Among them, battery-powered ships have become one of the focuses of the marine power industry. At present, inland shipping has the basic conditions for electrification, but the development of electric ships in my country is still in the early stage, and many bottlenecks remain to be solved. There is still a long way to go for the mature development and large-scale popularization of ship electrification.

 Electric boats are the trend

 In July 2018, the State Council issued the "Three-Year Action Plan for Winning the Blue Sky Defense War", proposing to adjust and expand the scope of ship emission control areas, promote the transformation of inland ships, promote the use of shore power for ships at ports, and speed up the upgrading of oil product quality. The "Ship Emission Control Area Adjustment Plan" issued by the Ministry of Transport proposes that from January 1, 2020, ships sailing in the coastal control area should use marine fuel with a sulfur content of not more than 0.5%, and not more than 0.1 during the berthing period. %, the inland water control area shall use compliant fuel oil in accordance with the requirements of the "Air Pollution Prevention and Control Law", and ships can adopt alternative measures such as exhaust after-treatment, clean energy, and shore power. The intensive introduction of environmental protection policies has brought a lot of pressure on the shipping industry to reduce emissions, and ship emission reduction has transformed inland shipbuilding into green.

 At present, the improvement of environmental protection requirements for ships has made the development momentum of electric ships stronger. Dr. Huang Zhaoxia, an expert from China Classification Society (CCS) Wuhan Institute of Standards, said in an interview with reporters, "Following the implementation of the 'dual carbon' policy by the state, the industry generally believes that the carbon reduction effect of pure battery-powered ships with zero carbon emissions is immediate. Up to now, there are nearly 300 electric ships in China, including more than 250 pure battery-powered ships, most of which are mainly inland river cruise ships.”

 It is reported that the current inland battery-powered ships include passenger ships, ferries, official ships, dry bulk carriers, etc. Electric ships have become the "green trend" of inland shipping. In 2020, the first thousand-ton electric cargo ship "Zhongtian Dianyun 001" in the Yangtze River was launched in Changzhou, and the first domestic large-scale all-electric commercial tourist ship "Junlv" shuttled over the Yangtze River in Wuhan; in 2021, "Jinlongyu" "Pearl River Princess" and "Pearl River Prince" three pure electric cruise ships were put into operation on the Pearl River; in 2022, the largest deadweight tonnage electric cargo ship in the Yangtze River basin, "Ship Link No. 1", made its maiden voyage in Nanjing, which filled my country's large-tonnage fuel oil. The blank in the field of all-electric transformation of cargo ships... In addition, pure electric salvage boats, tugboats, law enforcement vessels, etc. are also quickly put into the field of water transportation, providing strong kinetic energy for the green development of water transportation.

 "Reducing ship energy consumption, reducing environmental pollution, and improving shipping capacity have become the development trends in the field of inland shipping." At the 5th China Ship Power Technology Summit-Inland River Pure Electric Ship Technology Development and Application Summit Forum, July 12 Research Gui Wenbin, director of the institute, said that pure electric ships with the characteristics of "zero noise and zero emissions" will be the focus of the future development of the inland ship industry. In the future, the development and popularization of ship electrification presents an "imperative" trend.

 Overcoming problems is a long way to go

 As one of the frontier developments in the shipping industry, electric ships have obvious advantages. First of all, electric ships have excellent energy-saving and emission-reduction effects and have the characteristics of low energy consumption. Due to the high energy efficiency of DC propulsion, the energy efficiency conversion rate can basically reach more than 95%; secondly, the fuel cost of the diesel power system is high and the emission pollution problem is serious. Compared with other situations, the use of electric ships can greatly save fuel consumption. Pure electric ships also have the characteristics of low noise and high comfort, which are of great benefit to the development of inland river ecological construction.

 At present, electric ships, as the mainstream ships with zero carbon emissions, still have "two sides". On the one hand, due to the limitations of battery energy density technology, the current application of battery-powered ships is basically concentrated in short- and medium-distance inland waters and offshore ports. Due to the limited energy density of batteries and the limited storage space of ships, the "endangered" caused by the limited storage space can only be charged immediately. However, at present, most electric ships are equipped with their own charging devices and operate at fixed routes and terminals. The shore power system provided by the port has not been used on a large scale, and there are still insufficient coverage, insufficient energy storage capacity and incompatible equipment, etc. question.

 On the other hand, battery systems for electric ships are not intrinsically safe. Huang Zhaoxia said that the most critical issue facing electric ships at present is the safety risk of thermal runaway of lithium electronics. "Analogizing the analysis of many electric vehicle spontaneous combustion accidents at present, once a lithium-ion battery catches fire, there is no effective means to control the spread of the fire, and there is no choice but to escape. For ships sailing on water, the escape environment is worse than that of electric vehicles." The system is the only energy source for ship power. Once a problem occurs, the entire ship will lose power and power, and the consequences will be disastrous. It can be seen that the battery power system directly determines and affects the safety of the ship's navigation.

 In addition to the limitations of ship technology and safety, the cost and cost of electric ships and the optimization and improvement of the industrial chain are also important factors restricting the popularization and development of electric ships. Huang Zhaoxia believes that the cost of electric ships is affected by the cost of power batteries, and the cost of lithium batteries is relatively high. The battery life is generally 5-8 years, but the life cycle of the ship is 30 years, and the replacement cost is relatively high. Although from the perspective of electricity consumption, There are certain advantages in ship operation in the later stage, but the capital investment required in the early stage will bring a lot of economic pressure to ship owners.

 In addition, the supporting facilities and industrial chain of electric ships also need more sound construction. "Compared with other types of ships, electric ships belong to the 'new generation'. It is still in the early stage of development, and its product supporting facilities, including the standardization of its marine and power products, have yet to be developed, and industry chain enterprises are also required to cooperate." The chain's complete and orderly operation line. At the same time, the green development of the electric ship industry chain is equally important, and the green development of the whole process of ship design, production process and battery recycling and disposal is the goal to be achieved in the future." Huang Zhaoxia Say.

 Multi-faceted development is required

 Today, the trend of ship electrification is "rising tide", the output of electric ships is growing rapidly, and the market scale will gradually expand in the future. However, the development of electric ships is still in its infancy, and the large-scale promotion of ship electrification is still subject to various factors such as technology, infrastructure, and enterprise model. How to develop? In this regard, Huang Zhaoxia suggested steady progress from three aspects.

 First of all, it needs the support of policies and regulations at the national level. "The development of electric ships should follow the 'top-down' rule, and the formulation of policies and ship specifications is an absolute factor affecting development. Industrial development requires the country's overall layout and financial support, and corresponding policy support can better promote electric ships. At the same time, the standardization of ship supporting batteries, ship inspection regulations and construction specifications still need to be further improved by relevant departments." Huang Zhaoxia said.

 Second, encourage the innovative development of core technologies for electric ships. The CCS "Shipping Low-Carbon Development Outlook 2021" report pointed out that the current lithium-ion batteries mainly include lithium cobalt oxide batteries, ternary lithium batteries (nickel-cobalt-manganese), lithium manganate batteries, lithium iron phosphate batteries and lithium titanate batteries. The lithium-ion batteries have different battery performance. Energy density and safety are two aspects of performance that are of particular concern. At present, lithium iron phosphate batteries have the advantages of high temperature resistance, strong safety and stability, and better cycle performance in practical use. For ships, the priority of safety performance is higher than the cruising range. At this stage, lithium iron phosphate batteries are more in line with the needs of ship safety development. At the same time, Huang Zhaoxia said, "In the future, solid-state lithium batteries have better safety performance and higher energy density than traditional lithium electronic batteries, and can become a new choice for the development of ship batteries. Lithium electronic batteries are intrinsically safe, and ships are electrified. The road to popularization and development will be stable and far-reaching.”

 Finally, establish a comprehensive supervision platform system. "Considering that during the life of the battery application, the first element of being able to reasonably control the safety risks brought by the battery is to strictly control the performance and process of battery products in the early development. It is as important as supervision." Huang Zhaoxia pointed out that electric ships are in the early stage of development, and "industry rules" should be formulated from the beginning to maintain a good development environment for electric ships, so that the safe operation of ships can be further ensured in the future. "In addition, I suggest that the electric ship industry establish a third-end ship monitoring platform, which can use the real-time monitoring of big data to predict and control accidents in advance, and conduct safety hazard screening and condition-based maintenance for battery-powered ships, so as to ensure battery-powered ships. Ships are developing in a relatively healthy, safe and orderly direction."