Key difference between lead acid battery and lithium battery

Lead acid and lithium batteries are two major rechargeable battery solutions used extensively in various applications today. Understanding the key differences between the two battery chemistries is important when selecting optimal solutions for energy storage needs. This article analyzes and compares lead acid batteries versus lithium batteries across aspects like working principles, performance metrics, applications, and environmental impacts to give you a comprehensive perspective.

First looking at the working principles. There exists some difference between lead acid battery and lithium battery in terms of their fundamental operating mechanisms for storing and discharging electricity.

Lead acid batteries use lead-based compounds for the electrodes and sulfuric acid for the electrolyte. In the charge process, electric current drives a reversible chemical reaction causing the positive lead dioxide electrode to lose oxygen while the negative lead electrode gains oxygen. This oxidation-reduction reaction creates a potential difference, while also converting electrical energy into stored chemical energy. In the discharge process, the reaction reverses direction internally, converting lead sulfate back into lead electrodes while generating electron flow as electric current to power devices.

In contrast, lithium ion batteries utilize electrochemistries based on movement or intercalation of lightweight lithium ions between cathode and anode. Common lithium cathode materials like lithium cobalt oxide provide redox reaction sites for the lithium ions moving in/out upon charging/discharging. Graphite or silicon carbon composites act as the negative node accepting the migrating ions. Non-aqueous organic electrolytes provide the ion transport medium. Overall the back-and-forth intercalation process creates electron flow externally while storing energy internally, without changing electrodes’ crystalline molecular structures.

In terms of performance and lifespan, lithium batteries are far superior over traditional lead acid ones. Lithium batteries weigh much lower at equivalent capacities thanks to its lightweight cathode and anode materials. For example, a 48V 100Ah lithium battery would weigh just around 20kg, versus over 100kg for a similar lead acid battery. This significant weight difference gives lithium batteries substantial advantage in applications where low mass and high mobility are critical like electric vehicles and mobile devices.

Further, the lithium battery and lead acid battery differ considerably in energy density - a key performance parameter. Lithium batteries can reach energy densities between 120-265 Wh/kg or 250-620 Wh/L, about 3 to 5 times higher than lead acid batteries which normally deliver 30-50 Wh/kg or 60-120 Wh/L. The higher energy storage capacity packed into the same battery volume/weight enables lithium chemistry to power longer device runtimes or travel distances per charge.

On the sustainability aspect, a noticeable difference between lead acid battery and lithium battery is that lithium batteries also face more production and recycling issues compared to the crude but established lead acid technology. Raw material mining and battery manufacturing of lithium batteries consume significant non-renewable resources and energy. Expired lithium battery units contain persistent organic electrolytes and chemicals requiring sophisticated recycling methods not broadly available yet. At the same time, lead pollution remains a major concern for the lead acid industry, despite over a century of recycling experience. In essence both battery chemistries result in environmental issues which technology solutions must prioritize and address.

In summary, while lithium batteries deliver superior power performance especially for mobility uses, lead acid battery retain cost, safety and simplicity merits for basic electrical systems. Rather than claiming one chemistry clearly better, both lead acid battery and lithium battery technologies will likely continue evolving in complementary roles across various use cases.