When looking for a solar energy solution for your home or commercial building, the type of battery counts. Lithium-ion and lead-acid batteries have been a topic of discussion, making homeowners and business people wonder which battery is best for them. Every battery type has advantages and disadvantages and suitable for certain uses.
Knowledge of these differences enables you to make decisions that affect your energy storage system's efficiency, durability, and cost. Lithium-ion and lead-acid batteries are two of the most common types of batteries used in today’s technology, and this article outlines their differences in price, durability, efficiency, and more. After reading this article, you can determine the battery type to choose.
Lithium-Ion vs. Lead Acid Batteries Overview
The rechargeable battery market has long been dominated by two primary types of batteries, lithium-ion and lead-acid. These batteries meet different requirements and are suitable for various uses, each with pros and cons. Therefore, it is essential for homeowners or businesspeople looking for energy storage systems to understand the fundamental differences between these two types of batteries.
Overview of Lead Acid Batteries
Lead-acid batteries have been the industry pioneers for many decades. They remain the preferred choice for many conventional uses, including standby power, transportation, and some renewable power systems.
These batteries use lead dioxide and sulfuric acid to store energy, making them among the most reliable and long-lasting batteries. Their two main strengths are low price and durability, making them preferred by most people, especially those with a tight budget.
Overview of Lithium-Ion Batteries
Lithium-ion batteries are relatively new in the market compared to other battery types. These batteries have received much attention due to their better performance and flexibility.
Lithium-ion batteries store energy by transferring lithium ions between the anode and the cathode, which leads to higher energy density and efficiency. Therefore, they are ideal for modern applications requiring high energy density and long cycle life. They are used in electric vehicles, portable electronics, and new solar power systems.
The decision between these battery types concerns power or money and finding the best fit for you.
How Do Lithium-Ion and Lead-Acid Batteries Work?
Both lithium-ion and lead-acid batteries convert energy through chemical reactions in their basic functioning. These processes are different and include the following:
How Lead-Acid Batteries Work
Lead-acid batteries are popular because they work on a relatively simple chemical process. Inside each lead-acid battery cell are two plates: one made of lead dioxide and the other of sponge lead. These plates are immersed in a sulfuric acid solution, the battery's electrolyte. The sulfuric acid combines with the plates during discharge to form lead sulfate and water.
This chemical process releases electrons, which flow through an external circuit, supplying power to connected electrical appliances. This process is reversed when the battery is charged: the lead sulfate turns into lead and lead dioxide, and the sulfuric acid concentration is restored. Lead-acid batteries are reliable and have been used for more than 100 years, but they are not the most efficient or longest-lasting batteries on the market today.
How Lithium-Ion Batteries Work
On the other hand, lithium-ion batteries use a slightly more complicated mechanism that results in greater efficiency and energy density. Lithium ions are shuttled between an anode and a cathode through an electrolyte in a lithium-ion battery.
The anode is usually graphite and donates lithium ions during discharge, while the cathode is typically a lithium compound and collects lithium ions during discharge. This movement produces an electric current that supplies the connected appliances. When the battery is being charged, this process is reversed; lithium ions flow from the cathode to the anode to store energy for later use.
The control of this ion movement allows lithium-ion batteries to release more power with less physical substance than lead-acid batteries; hence, they are lighter and more compact.
How Do Lithium-Ion and Lead-Acid Batteries Compare?
The following are factors in which lithium-ion and lead-acid batteries compare:
Cost
Many homeowners and business owners consider the price of a battery first. Regarding the initial cost, lead-acid batteries have been cheaper for a long time, which may be why many people prefer them.
These batteries are usually more affordable and have a standardized market chain, so their cost is typically low. People operating under a small budget opt for lead-acid batteries. However, this can be deceptive, especially in the initial stages of a business or the commencement of a project.
Lithium-ion batteries have a higher initial cost but are cheaper in the long run. This is because of the advanced technology and materials required for their production. Lithium-ion batteries also have a much longer life expectancy than any lead-acid battery, meaning the user will not need to replace them as often. Considering all the possible costs of the battery, such as repair, durability, and energy consumption, lithium-ion batteries are more economical in the long run.
Capacity
Battery capacity is the ability of a battery to hold a charge, which determines how long it will take to power your gadgets or home. In this regard, lithium-ion batteries are much better than lead-acid batteries in terms of energy density. Lithium-ion batteries have a higher energy density, meaning they can store more energy in a given volume. This is especially the case where space is a constraint, such as for electric vehicles or portable electronics.
However, lead-acid batteries have lower energy density and, as such, need larger volumes to store the same energy as the other battery types. This may be a disadvantage in cases where the size and mass of the device are crucial factors in the design.
The Materials Used
Lead-acid batteries use lead plates and sulfuric acid as the main electrical current components. Lead, a heavy and cheap metal, has been part of battery technology for more than a century because of its high energy density and low cost of energy storage. However, lead is a toxic heavy metal. Proper management and disposal of lead-acid batteries are required since improper disposal or recycling can be hazardous to the environment.
Also, the sulfuric acid electrolyte is hazardous and may cause damage if it leaks. Lead-acid batteries are generally recyclable, though the process involves several controls to avoid polluting the environment.
Lithium-ion batteries are known to use more complex materials. The cathode of a lithium-ion battery is usually constructed from a lithium compound, for instance, lithium cobalt oxide or lithium iron phosphate. Similarly, it is common for the anode to be made of graphite simultaneously. Lithium is a soft, silvery metal that reacts easily with other elements. Because of this, these batteries can pack a great deal of energy into a small volume.
Battery Type
The type of battery is critical to its use, effectiveness, and overall performance. Lead-acid batteries come in two primary types: flooded and sealed with valve-regulated lead-acid batteries (VRLA). There are two types of flooded lead-acid batteries, namely the traditional one, where the electrolyte moves freely around the plates. These batteries need occasional maintenance, including periodic addition of distilled water to the electrolyte and adequate ventilation to avoid the buildup of the resulting gases.
Sealed lead-acid (SLA) or VRLA batteries, such as absorbent glass mats (AGM) or gel cell batteries, are completely non-maintenance. They have the electrolyte fixed in a gel or glass mat to avoid leakage and are relatively low-maintenance. Yet, sealed lead-acid batteries are not immune to problems such as sulfation if not charged and maintained properly.
In contrast, lithium-ion batteries have types that depend on the chemistry involved. Some types are lithium cobalt oxide (LCO), which has high energy density, and lithium iron phosphate (LFP), widely regarded for safety and endless cycling.
Energy Density
Energy density becomes important when comparing lithium-ion and lead-acid batteries, especially considering space and weight. Energy density is also known as energy per unit mass or volume, which means the amount of energy that can be stored in the battery compared to its size or weight.
In layperson's terms, a higher energy density means that a battery can store power that is even greater than required without occupying a lot of space or weighing a lot.
Lithium-ion batteries possess the highest energy density among battery types. This characteristic enables them to store a large amount of energy in a small volume, making them suitable for use in places where size and mass are of the essence.
For example, lithium-ion batteries stand out in electric vehicles or portable electronic devices, where every pound and square inch matters. The figure also shows that the high energy density leads to the long run time of these batteries, implying that they can be used for long periods before being recharged. This efficiency is partly why lithium-ion batteries have become the reference system in today’s technologies, from portable electronics to renewable energy systems.
However, lead-acid batteries have a significantly lower energy density than lithium-ion batteries. These batteries are larger and denser for the same energy storage capacity level, making them less ideal where space and mass are an issue. While they are still present in automotive and industrial applications, their low energy density prevents their use in areas that require density and size.
For example, if you intend to use the battery for off-grid solar applications, you need more space to accommodate the lead-acid battery than the lithium-ion battery.
Operating Temperature
Operating temperature is another critical factor to consider if your battery system will work in extreme conditions. The temperature at which the battery is used usually influences its performance, safety, and durability.
Lithium-ion batteries are characterized by their ability to deliver high performance under a wide temperature range. However, they are highly vulnerable to heat and can easily generate what is termed as thermal runaway, whereby the battery catches fire. Lithium-ion batteries are usually equipped with complicated thermal regulation systems to minimize this risk and keep the batteries at the right temperature.
On the other extreme, low temperatures in the lithium-ion battery system decrease the rate of lithium-ion batteries and thus discharge faster. However, battery technology still enhances the thermal stability of lithium-ion batteries, making them safer and more reliable across all climates.
Lead-acid batteries are slightly more tolerant to heat than lithium-ion batteries, but their performance decreases under high temperatures like the latter. High temperatures also cause corrosion of the battery components, reducing the battery’s life cycle. However, lead-acid batteries are known to be relatively more effective in cold climates than lithium-ion batteries.
While they do not suffer as much from cold-induced discharge problems, the disadvantage is that the system's efficiency reduces with falling temperatures. Hence, if you are using your equipment in a region where the climate is consistently hot, lead-acid batteries may need some form of cooling. They may do better in some areas in a cooler climate than lithium-ion batteries.
Depth of Discharge (DOD)
The Depth of Discharge (DOD) refers to the discharge level of a battery to the point where it has to be recharged. It is critical in defining the battery's life span and efficiency. The higher the DOD, the more the battery is discharged to obtain energy, reducing battery cycle life.
Lithium-ion batteries are perfect for DOD. They can frequently cope with 80% or more discharge rates without significantly declining efficiency and durability. This means that in each cycle of charging and discharging, one could utilize a greater percentage of the battery capacity, which is useful in applications where a battery undergoes extended power drain, such as solar energy storage or electric vehicles.
Lithium-ion batteries have a higher DOD, which means that they can be used more effectively with less charging required, and their full capacity can be used to their full advantage. Moreover, lithium-ion batteries can accept deep discharges without degrading significantly.
However, lead-acid batteries have a lower DOD, estimated to be between 40 and 50 percent. To ensure that they remain healthy and have a longer life span, it is recommended that you refrain from frequently discharging them up to fifty percent of their total capacity. Even though it is possible to discharge a lead-acid battery to a greater extent, its frequent deep discharge negatively affects its durability. It increases the number of replacements and total costs in the long run.
This limitation of lead-acid batteries means they are not ideal for use in applications where deep discharging is frequent since you are likely to charge the battery more often to avoid straining it. Nonetheless, suppose the energy demand is not high, and one can cope with the charging cycles. In that case, lead-acid batteries can be dependable and cheap, especially in cases where the lower DOD is not such a drawback, for example, in stationary applications.
Contact a Solar Energy Expert Near Me
Choosing between lithium-ion and lead-acid batteries means considering cost, efficiency, lifespan, and overall performance. Each battery type serves different purposes and meets varying energy needs. The ideal option depends on your specific requirements.
At Sun Solar Electric, we offer energy storage solutions and are here to guide you through the decision-making process. Whether you are powering your home with renewable energy or looking for an efficient storage solution for your business, we can help you determine the battery system that meets your goals. Call us at 707-658-2157 for expert advice and a custom solution tailored to your energy storage needs in the Bay Area and Northern California.
