Principle and characteristics of seawater battery

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Principle and characteristics of seawater battery

Principle and characteristics of seawater battery

Seawater battery generally refers to a battery with seawater as electrolyte.

It generally refers to the chemical power supply with seawater as electrolyte in the marine environment.

Electrolyte is an important part of battery. Its main function is to ensure the directional movement of ions in electrode reaction and form a stable and continuous current. There are many forms of electrolytes, such as solid, colloid and liquid. Liquid electrolytes include aqueous solution, organic solvent and molten salt. Seawater belongs to salt solution, and its composition is mainly about 3.5% NaCI, as well as a small amount of Mg2 +, Ca2 +, SO42 -, HCO3 - and a small amount of dissolved gases such as oxygen and carbon dioxide. From the perspective of composition, due to the fixed proportion of ions, Its conductivity meets the basic requirements of battery electrolyte.

According to the composition of seawater battery, the most prominent feature is that it does not need to carry electrolyte, and can use natural seawater to form electrolyte when needed. Based on such a structural feature, seawater battery has the following outstanding advantages:

(1) It does not need to carry electrolyte and special storage and control devices. Firstly, it reduces the weight of the battery and directly improves the unit energy density of the battery.

(2) A series of problems caused by carrying liquid electrolyte are avoided, such as storage container, storage stability and safety, low-temperature freezing and difficult flow of electrolyte, so that the relevant structure is simplified.

(3) The electrolyte is flowing seawater, which eliminates the polarization of reactants on the electrode to a certain extent, is conducive to the stability of electrode discharge performance, the electrode reaction is easy to reach thermodynamic equilibrium, and improves the efficiency of the electrode.

(4) The whole battery is an open system relative to seawater, which is balanced with the external pressure of seawater. The battery does not need to be placed in a special pressure vessel, and the structure is relatively simplified. Heat exchange can also be carried out through seawater flow, bringing out the heat released by electrode reaction, controlling the temperature of the battery system and significantly improving the safety.

(5) Because it is an open system, the variation of battery discharge performance with seawater depth is not obvious, so it is suitable for use in different depths.

(6) Through the selection of electrode materials, different kinds of batteries can be developed with wide adaptability and high cost performance.

However, the characteristics of seawater battery also bring some adverse factors:

(1) The temperature, salinity and flow rate of seawater have a certain impact on the discharge performance of the battery. This problem needs to be paid more attention in the research of high-power power battery.

(2) Generally, complex electrolyte control system is needed, including seawater inlet, distribution and discharge system, temperature control system and gas-liquid separation system, and the quality of this system directly affects the performance of the battery.

(3) Due to the use of dissolved oxygen as cathode materials, in order to ensure a certain current density, the cathode area is required to be large and the battery volume is huge.

【Energy network】

Principle and characteristics of seawater battery_Seawater battery