Chemical energy storage refers to various secondary battery energy storage methods that utilize chemical elements as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage media. Currently, chemical energy storage batteries mainly include lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, and flow batteries.
1. Lithium-ion batteries
Lithium-ion batteries are batteries that use lithium metal or lithium alloys as the negative electrode material and employ a non-aqueous electrolyte solution. Due to their high energy density, long lifespan, and wide operating temperature range, they have taken a leading position in electrochemical energy storage installations in recent years. However, lithium-ion batteries also have some inherent disadvantages when used for energy storage, such as short lifespan, high cost, and potential safety hazards.
2. Lead-acid batteries
Lead-acid batteries are rechargeable batteries whose electrodes are primarily made of lead and its oxides, and whose electrolyte is a sulfuric acid solution. Lead-acid batteries have widely available materials and low cost, but their disadvantages include a low cycle life, short lifespan, and the potential for environmental pollution if not properly handled during production and recycling.
Today, lead-acid batteries are widely used internationally, with a cycle life of up to 1,000 cycles and power efficiency of 80%-90%. They are cost-effective and are often used as emergency power or backup power in power systems.
3. Sodium-sulfur batteries
Sodium-sulfur batteries are secondary batteries that use metallic sodium as the negative electrode, sulfide as the positive electrode, and a ceramic tube as the electrolyte membrane. Sodium-sulfur batteries have advantages such as small size, large capacity, long lifespan, and high efficiency. They are widely used in power storage applications such as peak shaving and valley filling, emergency power supplies, and wind power generation.
4. Flow battery
Flow batteries, generally known as redox flow batteries, are a new type of large-scale electrochemical energy storage device. Those using vanadium salt solutions for both positive and negative electrodes are called vanadium redox flow batteries, or simply vanadium batteries. Vanadium redox flow batteries are a novel type of energy storage equipment that can be used not only as energy storage devices in conjunction with solar and wind power generation processes, but also for grid peak shaving, improving grid stability, and ensuring grid security.
Compared with other energy storage batteries, flow batteries have advantages such as flexible design, fast charge and discharge response, good performance, long battery life, easy regeneration and recycling of electrolyte solution, high degree of site selection freedom, high safety, environmental friendliness, high energy efficiency, and fast start-up speed.
