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Battery Day2021

RECOGNIZING THE IMPACT OF BATTERIES ON NATIONAL BATTERY DAY

Join U.S. Battery in celebrating February 18th, National Battery Day! NBD allows us to celebrate the impact batteries have in our daily lives and reminds consumers of the recycling efforts essential to allow batteries as a vital energy source.

Overall, the battery industry plays a vital role in everything from transportation, medical, aerospace and defense, communication, renewable energy, and other industries. One of the most common batteries in use is lead batteries, mainly because of their high efficiency, low cost, and the fact that they are also nearly 100 percent recyclable. U.S. Battery deep-cycle, lead battery products, for example, are used in everything from aerial lifts to off-grid housing, floor cleaning machines, and many other applications.

Economic Impact

According to the Battery Council International, the non-profit trade association for the lead battery industry, lead batteries are a proven technology with more than 160-years of unmatched resiliency and reliability. They also report that lead batteries provide more than 90-percent of the backup power required for 24/7 telecommunications and backup recovery systems that protect lives, investments, and data in an emergency. Within the transportation and motive power sectors, 12V lead batteries have a projected growth reaching more than six percent in the automotive market alone between 2015 and 2030, bringing the market value to $31.9B.

In the United States, lead batteries provide a $26.3-billion impact on the economy that involves suppliers, worker spending, transportation, and distribution. It provides an estimated $1.7-billion in annual payroll, supporting an industry that employs nearly 25,000 workers. Aside from studies that show lead-acid batteries are the safest and most reliable sources of energy, studies show they also represent some of the lowest cost-of-operation options available.

Good For The Environment

Another reason to celebrate batteries on NBD is that they are the most recycled consumer product, recognized by The U.S. Environmental Protection Agency. The recycling process breaks down the outer casings made of polypropylene, then washed, melted, and extruded into small pellets. Manufacturers use these pellets to produce new battery cases as well as other plastic products. The lead oxide and lead grids of the battery’s interior are melted in a smelting furnace to form lead ingots to make new battery components. The sulfuric acid in the battery’s electrolyte is neutralized and purified into water that meets EPA clean water standards before being recirculated. The recycling process converts the acid into sodium sulfate, a compound commonly used in laundry detergent, glass, and other textiles. The process creates a sustainable energy source that is the model of recycling in the United States.

A Sustainable Energy Source

The U.S. Department of Energy is also looking at the role lead batteries may have on the future of energy storage because of its recycling rate, strong domestic base, high safety record, and low-cost efficiency. The DOE issued a 2020 report on Grid Energy Storage Technology Cost and Performance Assessment that includes lead batteries as one of seven storage technologies receiving attention, along with lithium batteries.

While it’s great to acknowledge that batteries have provided consumers and industries with a viable energy source for more than 150 years,  NBD reminds us to be responsible consumers. As batteries become more of an important energy source, it’s reliant upon industries and consumers to familiarize themselves with the various chemistries, where your batteries come from, and how each type of battery can be properly disposed of and recycled.

One of the most important things you can do to observe NBD is to gather old or used batteries and properly recycle them. Disposing of batteries in landfills can cause chemical and fire hazards. Therefore, finding a local store, organization, or recycling facility is an essential part of the process. To do this, the Battery Council International recommends using www.call2recycle.org, a national non-profit organization, to help consumers identify the various battery types and to locate local recycling centers and disposal options.

TTBLS structure grown with additives

Improving Deep-Cycle Batteries Through Additives

Battery manufacturers have improved deep cycle battery performance through the use of additives, but not all of them result in the same benefit to customers. At the core of all deep-cycle flooded lead-acid (FLA) battery technology is a basic design that has undergone continuous improvement over more than 100 years. Lead battery chemistry is one of the most reliable and cost-effective technologies over any other type of battery used in a variety of global industries. While these batteries have historically been the most widely used and the most recycled, a variety of additives and technologies have been introduced over the last few years to improve their efficiency to an even greater extent.

Grid Alloys

Historically, the primary failure mode of deep-cycle lead-acid batteries has been positive grid corrosion. The grid alloys used to manufacture deep-cycle flooded lead-acid battery plates typically consist of lead with additions of antimony to harden the soft lead, and to improve the deep cycle characteristics of the battery. Additional metals are often added to the lead-antimony alloys to improve strength and electrical conductivity. Another additive that is used to enhance lead-antimony alloys is selenium. Selenium acts as a grain refiner in lead-antimony alloys. This fine-grain alloy provides additional strength and corrosion resistance over conventional lead-antimony alloys. The effect of these improvements is that positive grid corrosion is no longer the primary failure mode, and the cycle life of FLA deep cycle batteries has been significantly increased.

Active Materials

The starting materials for deep cycle FLA positive active materials are made from a mixture of lead oxide, sulfuric acid, and various additives. These materials improve the performance and life of the positive electrodes in a finished battery. Historically, positive electrodes have been processed using a procedure called hydroset. This procedure is designed to ‘grow’ tetrabasic lead sulfate (TTBLS) crystals in the plates to provide the strength to resist the constant expansion and contraction of the active materials during cycling. This crystal growing process has limitations in its ability to control the range of sizes of the TTBLS crystals. Through the use of crystal seeding additives, the range of crystal sizes can be controlled to the most desirable sizes. These uniform crystal sizes in the TTBLS structure result in increased initial capacity, faster cycle-up to rated capacity, higher peak capacity, and improved charging using the wide range of charger technologies used in various applications.

Concurrent with the improvements in deep cycle FLA positive active materials, improvements in the performance of deep-cycle FLA negative active materials are needed. Carbon additives have been used in the negative active materials of lead-acid batteries for many years. These additives have been used in lead-acid battery expanders to prevent the natural tendency of the negative active material to shrink or coalesce during cycling. Negative active material shrinkage can reduce the capacity and life of deep-cycle FLA batteries. Recent improvements in these carbon materials have opened up new opportunities to improve several performance limitations of lead-acid batteries. New structured carbon materials such as graphites, graphenes, and nanocarbons have been used to control sulfation and improve chargeability in a partial state of charge (PSOC) applications such as renewable energy.

Although the basic structure of an FLA battery hasn’t changed for more than 100-years, manufacturers are continually searching for ways to improve efficiency while maintaining their cost-effectiveness. Additives are one of the ways FLA batteries are becoming more efficient, and new technologies to further enhance them are on the horizon.

Renewable Energy Storage Options: AGM vs FLA Batteries

Energy-conscious businesses and homeowners who are looking to store energy from their wind or solar energy systems, often consider the differences between using a no-maintenance AGM (Absorbed Glass Mat) and an FLA (Flooded Lead-Acid) deep-cycle batteries. While each type of battery has its advantages, here are some facts that can help you make the right decision for your particular application.

 

Higher Cost, Lower Maintenance

 

If you want a low maintenance renewable energy system’s battery bank, a set of AGM batteries are the ideal choice. Deep-cycle models can be successfully used for energy storage. Because they are sealed and featured glass matt separators that retain all of the electrolyte without water, there’s no need to periodically add water.

 

The drawback, according to U.S. Battery Senior VP of Engineering Fred Wehmeyer, is the cost. “AGM batteries typically cost from 25 to 50 percent more per watt-hour compared to FLA batteries,” says Wehmeyer. “Besides, AGM batteries may also not last as long as premium FLA batteries used in these types of applications.”

 

Lower Cost, Higher Maintenance

 

When lower total operating costs are the goal, FLA batteries offer the lowest cost per watt-hour than any other type of battery storage system available. According to Wehmeyer, deep-cycle FLA batteries are robust and have been used very successfully for energy storage for several decades. “Less expensive than AGM batteries, FLA batteries offer the best cost per watt-hour than any other energy storage method available,” says Wehmeyer.

 

If you’re not opposed to routine maintenance, Wehmeyer adds that premium FLA batteries (those with higher lead content) will last longer than AGM batteries. Because FLA batteries lose water from evaporation during charging, they need to be regularly replenished, as well as cleaning and checking the terminals. Wehmeyer also recommends to occasionally performing an equalization charge on FLA battery banks used for energy storage. “Equalization charging is extremely important to optimize the life of renewable energy batteries,” he says. “It is used to both balance the individual cells in a battery pack and to mix the electrolyte through gassing to prevent electrolyte stratification.”

 

Gaining Optimum Performance From Both

 

No matter what type of batteries you choose for your renewable energy storage, deep-cycle batteries work best when the depth of discharge of your battery bank is kept to 50-percent. “For best performance and longest life, the batteries should be fully recharged regularly,” says Wehmeyer. “Depending on the source of recharge provided (solar, wind, generator, or AC power), full charging may not always be possible every day. Most batteries can operate efficiently in a partial state of charge condition as long a full charge is done at least every 30 days.”

AGM and Flooded Deep-Cycle Batteries

Understanding the Differences Between AGM And Flooded Deep-Cycle Batteries

When it comes to powering electric vehicles like golf carts, deep-cycle lead-acid batteries are the industry standard. The reason is that they are designed to provide the most cost-effective energy storage and delivery over the life of the battery.

Over the years, there have been two main types of deep-cycle lead-acid batteries that many golf car owners and fleets have used, the Flooded Lead-Acid (FLA) battery and the Absorbed Glass Mat (AGM) battery. While both provide optimum performance in a wide variety of applications, their design difference can offer various advantages depending on the application.

Engineering

The main design difference between FLA and AGM batteries is how the electrolyte is managed. In FLA batteries, the battery plates are submerged in the liquid electrolyte. During use, water in the electrolyte is broken down into oxygen and hydrogen gases and water is lost. This requires regular additions of water to be replaced to keep the battery plates fully submerged in the electrolyte.

In AGM batteries, the electrolyte is absorbed in special glass mat separators that retain all the electrolyte needed for the life of the battery.  Since there is no free electrolyte, the oxygen generated on a charge is recombined at the negative plate.  In normal operation, hydrogen is not generated and no water is lost.  This eliminates the need to add water and also allows the battery to be sealed with a one-way valve that prevents leakage of the electrolyte.

Performance Differences

FLA batteries have been used in a wide variety of applications for well over 150 years. Their popularity comes from their safety, reliability, and cost-effectiveness when compared with other types of rechargeable batteries.   According to Fred Wehmeyer, U.S. Battery Senior VP of Engineering, FLA batteries deliver the lowest cost per watt-hour both in acquisition cost and in overall cost per charge/discharge cycle.  “This is why they are the best choice for fleets of vehicles or equipment that are used heavily on a daily basis,” says Wehmeyer. “Also, both FLA and AGM batteries offer an environmental advantage over other types of batteries because they are essentially 100 percent recyclable and enjoy the highest recycling rate of any commercial product.”

AGM batteries offer the advantage of being maintenance-free. This can be significant in applications where regular maintenance is difficult or costly, such as when the batteries are located in remote or hard to access locations. Even though AGM batteries cost more per watt-hour, the elimination of maintenance costs reduces the overall battery operational costs.  Also, since the battery is sealed and does not emit gases in normal use, it can be used in sensitive areas such as food or pharmaceutical storage facilities.

Selecting between FLA or AGM deep cycle batteries ultimately depends on the type of use and the capability to provide regular maintenance in the application.

AGM = No Maintenance + Higher Cost + Susceptible to abuse like overcharging

FLA = Requires Watering + Lower Cost + Susceptible to abuse from poor maintenance

No matter what type of battery you use, it is always best to target the depth of discharge to 50 percent or less for both FLA or AGM battery types. This will optimize battery life cycle cost vs acquisition cost over the life of the battery system.