What are the differences between lithium batteries and lead-acid batteries?

Although both are types of batteries, their primary differences lie in the materials used for manufacturing and their discharge performance, which in turn leads to differences in their application fields.

1. Material Differences

(1) Lithium Battery Manufacturing Materials

Lithium batteries include polymer lithium batteries, lithium cobalt oxide batteries, ternary lithium batteries, and lithium iron phosphate batteries. The main materials used in their manufacture are:

Cathode Materials: Commonly used materials include lithium cobalt oxide, manganese oxide, lithium iron phosphate, and ternary materials (nickel-cobalt-manganese polymer). The cathode material significantly affects the performance and cost of lithium-ion batteries, with a mass ratio of 3:1 to 4:1 to the anode material.

Anode Materials: Currently, the primary anode materials are natural graphite and artificial graphite. Other materials under exploration include nitrides, PAS, tin-based oxides, tin alloys, nano-anode materials, and other metal intercompounds. Anode materials play a crucial role in enhancing battery capacity and cycle performance, making them a core component in the midstream of the lithium battery industry.

Separator Materials: Marketized separators are primarily made of polyethylene (PE) and polypropylene (PP). The separator is a critical internal component that affects the battery’s interface structure, and internal resistance, and directly impacts capacity, cycle performance, and safety. High-performance separators are essential for improving the overall performance of the battery.

Electrolyte: Typically composed of high-purity organic solvents, electrolyte lithium salts, and necessary additives, the electrolyte facilitates ion conduction between the cathode and anode, ensuring the high voltage and high energy density advantages of lithium-ion batteries.

(2) Lead-Acid Battery Manufacturing Materials

The composition of lead-acid batteries includes plates, separators, casing, electrolytes, lead connectors, and terminals.

Plates: Comprising a positive plate (lead dioxide, PbO2, dark brown) and a negative plate (spongy pure lead, Pb, gray), both plates have a grid structure filled with active material. The plates facilitate the conversion of electrical energy to chemical energy and vice versa during charging and discharging.

Separator: To reduce internal resistance and size, the positive and negative plates are placed as close as possible, with separators to prevent short circuits. Separator materials include wood, microporous rubber, microporous plastic, glass fiber, and cardboard, which must be porous, permeable, and chemically stable.

Casing: Made of acid-resistant, heat-resistant, shock-resistant, and insulating materials, the casing holds the electrolyte and plate group. The casing features ribs at the bottom to support the plates and collect shed active material, preventing short circuits.

Electrolyte: Composed of pure sulfuric acid and distilled water, with a typical density of 1.24 to 1.30 g/ml, the electrolyte facilitates ion conduction during the electrochemical reactions of charging and discharging. The purity of the electrolyte is crucial for battery performance and longevity.

2. Discharge Performance Differences

  1. Low-Temperature Performance: Lithium batteries perform better than lead-acid batteries in low-temperature environments.
  2. Cycle Life: Lithium batteries have roughly double the cycle life of lead-acid batteries.
  3. Working Voltage: Lithium batteries have a working voltage of 3.7V compared to 2.0V for lead-acid batteries, with a higher discharge platform.
  4. Energy Density: Lithium batteries have a much higher energy density than lead-acid batteries.
  5. Weight and Flexibility: Lithium batteries are lighter and offer more flexible sizing and shapes compared to lead-acid batteries with the same capacity and voltage.

Despite these advantages, lead-acid batteries maintain a strong position in traditional and some emerging fields due to their high current discharge performance, stable voltage characteristics, wide temperature range applicability, large single-cell capacity, high safety, abundant and recyclable raw materials, and low cost.

3. Application Field Differences

Due to their higher energy density, flexibility in size and shape, lithium batteries are preferred for lightweight smart devices, such as wearable electronics, portable power banks, etc. Conversely, lead-acid batteries, with their uniform shape and larger, heavier design, are commonly used in energy storage devices and equipment that cannot rely continuously on AC power sources.