Powering the Future: How Batteries Are Revolutionizing Energy Storage

1. Technical Principles of Different Types of Energy Storage Batteries

        Lithium-ion batteries are primarily composed of a positive electrode, a negative electrode, an electrolyte, and a separator. During charging, lithium ions in the positive electrode are deintercalated, passing through the electrolyte and the separator to be embedded in the negative electrode, while electrons travel through an external circuit to the negative electrode. During discharge, lithium ions are deintercalated from the negative electrode, returning to the positive electrode through the electrolyte, while electrons flow through an external circuit to the positive electrode, generating an electric current. Sodium-ion batteries have a similar structure to lithium-ion batteries. During charging, sodium ions are deintercalated from the positive electrode and embedded in the negative electrode, while during discharge, sodium ions return from the negative electrode to the positive electrode. Lead-acid batteries use lead dioxide as the positive electrode, spongy lead as the negative electrode, and sulfuric acid as the electrolyte. During charging, the lead dioxide in the positive electrode and the spongy lead in the negative electrode are converted to lead sulfate, respectively, while the reverse occurs during discharge.

2. Performance Characteristics, Advantages, and Disadvantages of Various Energy Storage Batteries

        Lithium-ion batteries offer high energy density and a long cycle life of 300-500 cycles (lithium iron phosphate batteries offer over 1500 cycles), but they are relatively expensive and pose safety risks such as overcharging and over-discharging. Lead-acid batteries are mature technology, offer good safety and environmental performance, and are relatively low in cost. However, they have low energy density and a short cycle life, typically less than 200 cycles, and are contaminated by heavy metals. Sodium-ion batteries are abundant and inexpensive, and using aluminum sheets as current collectors can further reduce costs. They also have high specific capacity, strong diffusion capacity, and low desolvation energy. However, their energy density and cycle life currently lag behind those of lithium-ion batteries.

3. Energy Storage Battery Applications

    In grid energy storage, lithium iron phosphate batteries, due to their low cost and high safety, are often used for peak shaving and valley filling. For example, they charge during low-demand periods and discharge during peak periods, alleviating pressure on the grid. For new energy vehicles, lithium-ion batteries, with their high energy density and long lifespan, have become the mainstream choice, providing long-lasting power. In renewable energy grid integration scenarios, energy storage batteries can smooth out fluctuations in intermittent power sources like wind and solar, reducing impact on the grid and increasing renewable energy utilization. Both lead-acid and lithium-ion batteries are used in behind-the-meter energy storage, allowing users to charge when electricity prices are low and discharge when prices are high, saving electricity costs.