Batteries that operate in partial state of charge (PSOC) environments can suffer from reduced charge acceptance that can lead to progressive capacity loss.
Using Carbon Additives to Improve Performance of AGM Batteries
Q&A with Fred Wehmeyer, VP of Engineering | US Battery
Tell us about yourself and your role with US Battery.
I am the Senior Vice President of Engineering for US Battery Manufacturing Company, Inc. I have been in the rechargeable battery industry for 48 years and have experience in FLA, AGM, GEL, NiCd, NiMH, Lithium Ion and Lithium Polymer rechargeable batteries. I have a Bachelor of Science Degree in Electrochemistry and have done graduate work in Engineering Management and Six Sigma/Lean Engineering.
To refresh everyone, what is the difference of an AGM battery versus a flooded lead acid and Lithium battery?
Flooded lead acid (FLA) batteries contain free liquid electrolyte that can spill out if the battery is tipped more than ~45⁰. There are both deep cycle versions and non-deep cycle versions of FLA batteries. Non-deep cycle versions are used in SLI (engine start) applications and should not be used in deep cycle applications. Deep cycle FLA batteries require regular water addition while maintenance-free SLI batteries normally do not. Absorbed Glass Mat (AGM) batteries are a type of sealed valve regulated lead acid (VRLA) batteries.
The other type of sealed VRLA battery is the gelled electrolyte (GEL) battery. VRLA batteries are essentially non-spillable and can be used in any geometry except upside-down. VRLA batteries do not require water addition and are usually sealed except for a one-way valve.
Lithium batteries are available in both rechargeable (secondary) and non-rechargeable (primary) versions. Rechargeable lithium batteries are available as lithium ion, lithium metal and lithium polymer versions. The most popular are lithium ion batteries that are available in a variety of lithium chemistries. Some examples are lithium cobalt oxide, lithium nickel cobalt oxide, lithium manganese oxide, lithium nickel manganese cobalt oxide and lithium iron phosphate.
What, if any are some of the performance differences between an AGM and a FLA battery?
FLA batteries have higher energy density than AGM batteries but AGM batteries have higher power density. Consequently, AGM batteries are often found in applications requiring high current discharges such as engine start or UPS systems. Since AGM batteries do not require water addition, they are typically found in applications where maintenance is difficult or costly such as on a mountain top. Since AGM batteries are sealed, they can be used in office environments, in food or drug storage environments or other clean room applications.
AGM batteries have a higher acquisition cost per watt-hour but often have a lower operational cost because of the need for maintenance of FLA batteries.
U.S. Battery Manufacturing’s new AGM Deep Cycle battery line is “advanced.” What does that mean?
U.S. Battery’s advanced AGM deep cycle battery line features improved cycle life and higher charge acceptance to more closely match lithium ion battery performance. This is achieved through the use of thick positive plates, high density positive active material, advanced glass mat separator technology and advanced carbon technology.
We’ve heard of carbon additives in batteries before, but what exactly does this do to improve performance?
Batteries that operate in partial state of charge (PSOC) environments can suffer from reduced charge acceptance that can lead to progressive capacity loss. This is often referred to as a decrease in Dynamic Charge Acceptance (DCA). Advance carbon additives can be use in both FLA batteries to improve DCA in Enhanced Flooded Batteries (EFB) for start/stop vehicles and in AGM batteries to improve DCA.
When used for energy storage, what makes these new AGM Deep Cycle batteries more advantageous?
U.S. Battery’s advanced AGM deep cycle batteries offer significant advantages in energy storage including higher charge acceptance to accept higher charge rates for faster charging. They also offer improved Dynamic Charge Acceptance to resist the deleterious effects of PSOC operation often encountered in solar, wind and micro-hydro energy storage applications.
What types of industries utilize lead AGM batteries and why?
As discussed above, AGM batteries offer higher power density and are often found in engine start, uninterruptible power systems, and high power energy storage applications.
Since they are sealed, they can be used in offices, food and drug storage and clean room applications.They are also less likely to freeze in cold temperature applications such as cold food and drug storage.
Can AGM Batteries also be 100 percent recycled and if so what impact does that have on the environment and on companies that are using recyclable batteries?
All lead batteries are both 100% recyclable and essentially 100% recycled in the US and most of the developed world. In addition, they are truly cradle-to-cradle recyclable, i.e. 100% of the recycled lead is used to make new lead batteries. This prevents hundreds of millions of pounds of lead from entering landfills and other deleterious waste streams.
In all 50 US states, it is a misdemeanor to dispose of a lead battery in municipal waste streams.
In addition, lead batteries have a significant value in the recycling process and ‘pay their own way’ when recycled.
The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag
U.S. Battery Manufacturing Company
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