What is the difference between lead acid and lithium batteries

As technical engineers specializing in the design of lead-acid battery recycling plants, GME’s team would like to provide a detailed and informative comparison between lead-acid and lithium-ion batteries. Both types of batteries serve as power storage devices with distinct advantages and disadvantages, depending on the application.

Chemistry and Components Lead-acid batteries

The lead-acid battery comprises a set of electrochemical cells, each consisting of a lead (Pb) anode, a lead dioxide (PbO2) cathode, and a sulfuric acid (H2SO4) electrolyte solution. The electrochemical reactions within the cells involve the conversion of lead and lead dioxide to lead sulfate (PbSO4) upon discharging, and the reverse process during charging.

Chemistry and Components Lithium-ion batteries

In contrast, lithium-ion batteries consist of an anode typically made of graphite, a cathode made of lithium metal oxide (such as LiCoO2, LiFePO4, or LiNiMnCoO2), and an electrolyte composed of lithium salts dissolved in a solvent (usually a mixture of organic carbonates). The fundamental electrochemical process in these batteries involves the reversible intercalation and deintercalation of lithium ions between the anode and cathode materials.

Energy Density and Specific Energy:

Lead-acid batteries have a lower energy density (30-50 Wh/kg) and specific energy (20-50 Wh/L) compared to lithium-ion batteries (150-200 Wh/kg and 250-670 Wh/L, respectively). This implies that lithium-ion batteries can store more energy per unit of weight and volume, making them more suitable for portable and lightweight applications.

Top 5 disadvantages of lithium-ion batteries

While lithium-ion batteries offer several advantages over lead-acid batteries, they also have some disadvantages:

1. Cost: Lithium-ion batteries are generally more expensive to manufacture and purchase due to the higher costs of raw materials, such as lithium and cobalt, and the more complex manufacturing processes involved. This may make them less attractive for certain applications, particularly when budget constraints are a significant factor.
2. Safety concerns: Lithium-ion batteries can pose safety risks if not properly managed. Thermal runaway, a process where a rise in temperature causes a further increase in temperature, can occur due to short-circuiting, overcharging, or physical damage. This may result in fires or explosions. Therefore, strict safety measures and protection circuits are required to prevent such incidents.
3. Sensitivity to high temperatures: Lithium-ion batteries are more sensitive to high temperatures compared to lead-acid batteries. Exposure to elevated temperatures can result in accelerated capacity loss, reduced cycle life, and potential safety hazards.
4. Aging and capacity loss: Lithium-ion batteries exhibit capacity loss over time, even when not in use. This aging effect is influenced by various factors, such as temperature, state of charge, and cycling patterns. Although lead-acid batteries also experience aging, the rate of capacity loss in lithium-ion batteries can be higher.
5. Recycling and environmental concerns: While recycling technologies for lithium-ion batteries are continuously improving, their recycling rate remains relatively low compared to lead-acid batteries. This is due to the complex chemistries involved and the lack of established recycling infrastructure for lithium-ion batteries. Additionally, the extraction of raw materials, such as lithium and cobalt, can have significant environmental and social impacts.

Which battery lasts longer lead-acid or lithium-ion? Why?

In terms of cycle life and overall service life, lithium-ion batteries generally last longer than lead-acid batteries. The reasons for this difference can be attributed to several factors:

• Depth of Discharge (DoD): Lead-acid batteries have a limited depth of discharge, typically around 50%, to maintain a reasonable cycle life. Discharging them beyond this point can result in a significant reduction in the number of charge-discharge cycles. Lithium-ion batteries, on the other hand, can be discharged to a much greater extent (up to 80-90% DoD) without compromising their cycle life.
• Cycle life: Lithium-ion batteries usually have a higher cycle life compared to lead-acid batteries. A lithium-ion battery can offer between 1,000 to 5,000 cycles, depending on the specific chemistry and use conditions. In contrast, a typical lead-acid battery may provide 300 to 1,000 cycles, depending on the battery type (flooded, AGM, or gel) and the depth of discharge.
• Self-discharge: Lead-acid batteries tend to have a higher self-discharge rate, meaning they lose charge even when not in use. This can contribute to a reduced service life, particularly in situations where the battery is not maintained at an optimal state of charge. Lithium-ion batteries have a much lower self-discharge rate, typically less than 5% per month, which enables them to maintain their charge for longer periods.
• Resistance to sulfation: One of the primary causes of capacity loss and reduced service life in lead-acid batteries is sulfation, a process where lead sulfate crystals form on the electrodes and hinder the electrochemical reactions.