Currently, the most commonly used power system for ships is the diesel engine ship power system, but there are many problems with the diesel engine power system. First, diesel engines use heavy oil or non-renewable energy, which puts great pressure on resources and has extremely high operating costs. Second, the noise and vibration problems generated during the operation of diesel engines are difficult to solve. Third, the exhaust gas and waste emissions of diesel engines are extremely serious, causing pollution to the environment.

With increasing attention paid to environmental pollution and resource shortages, the pollution problem in the shipping industry has also attracted more and more attention. Ships are major emitters. In recent years, the shipping industry of various countries has taken active actions to continuously promote and expand the application of green ship technology.

Although the industry is concerned about many types of new energy for ships, such as LNG, methanol, LPG, biomass fuel, solar energy, hydrogen, fuel cells, lithium batteries, etc., the only new energy power that can truly achieve zero emissions and is gradually promoted in the shipping industry and has an initial market scale is currently lithium battery electric ships. Pure battery-powered ships are mainly suitable for occasions with fixed routes, short voyages, and convenient replenishment points. For occasions with relatively long route distances, diesel-electric hybrid power can better take into account energy conservation and emission reduction and range adaptability.

1. Application of lithium batteries in pure electric ships

Compared with traditional propulsion systems, electric propulsion systems have the characteristics of good economy, flexible operation, high safety, low vibration and high reliability. Electric propulsion systems are now widely used in ferries, dredgers, tugboats and large cruise ships. With the rapid development of power electronics technology and the increasing energy crisis, electric propulsion has replaced traditional diesel engine propulsion and become an unstoppable trend.

2. Application of lithium batteries in hybrid ships

1) Power retention to prevent the ship from losing power.
2) Peak shaving and valley filling: When the load is the largest, lithium batteries can be used for short-term power supply; when the load is small, the power grid charges and supplements the lithium batteries.
3) Make up for the lack of characteristics of the generator set: the sudden load can be transferred to the battery pack to bear, effectively avoiding the risk of "stifling".
4) As electricity, it directly supplies power to the grid: the ship is not equipped with a diesel generator, and the battery system is directly used to power the equipment on board. The propulsion system uses electric motors to provide power, which can achieve "zero emissions" for ships.