Current generation of batteries (OasisTM) are manufactured with carbon foam only in the negative plates. The next generation battery, expected in production in 2016, will incorporate the carbon foam in both plates.
The carbon foam batteries have been used under conditions of extreme vibration and impact in applications such as transit buses – carbon foam plates have a higher yield strength than lead plates and have high compressive strength.
Firefly’s carbon foam plate technology, with its advantages of low cost and high energy density, can play a role in certain classes of hybrid and electric vehicles, such as buses, golf carts, forklift trucks, wheel chairs, boats, and electric scooters.
Performance of lead acid batteries depend on the surface area of plates available for chemical reaction and the least resistant pathways for electron flow. The surface area available for chemical reaction in a Firefly microcell foam plates is 2000 times more than what is available in a conventional lead acid battery.This yields higher energy density; faster charge and discharge times, higher efficiency and greatly improved cold weather performance.
Firefly’s carbon foam electrode does not corrode. The carbon foam also dissipates heat effectively – the battery operates cooler and more consistently. Sulfation is caused by the growth of sulfate compounds that coat the plates which blocks the conductive path required for charging. Firefly’s patented foam plates are designed to be in balance with the electrolyte and are localized within a very specific area. The catalytic effects of the carbon surface directs the crystal morphology, not allowing large crystals to grow. The composition and configuration of Firefly’s plates are resistant to the effects of sulfation.
There is an existing infrastructure to recycle lead acid batteries. Because Firefly’s technology uses carbon, it actually decreases the amount of lead in the battery. Firefly’s microcell technology can be recycled through the existing lead acid infrastructure.
Firefly’s technology substitutes lightweight carbon foam for much of the lead metal plates in a conventional lead acid battery. The carbon foam also allows greater electron flow for higher efficiency, and is highly resistant to sulfation. Durability, long life, light weight and low cost.
Ni-Cd Battery Technology, The sealed nickel-cadmium (or Ni-Cad) battery was introducedto meet the need for a compact rechargeable technology. It was successfully incorporated into a wide range of consumer products, such as power tools. Ni-Cad batteries are not suitable for applications requiring a large amount of energy storage. They are:
- Expensive and heavy
- Subject to capacity loss due to “memory effect” and prone to going dead in long term storage.
- Environmentally toxic – require special handling for disposal.
Nickel-metal-hydride (NiMH) battery This is a newer technology that was introduced in the 1970s. Although they perform batterthan Ni-Cad batteries, the chemistry has limitations:
- High Cost – limited deep discharge cycle life and shelf life
- Require tightly controlled voltage and current parameters during charging.
- Degrades if not used regularly.
- Unsuited for use in temperature extremes – permanent capacity loss.
Lithium-Ion Technology Lithium-ion (Li-ion) are commonly used in consumer devices such as lap top computers, cell phones, digital cameras, etc.; they are light weight and compact. Since their mass market commercial introduction a few years ago,problems have recently surfaced. Nearly six million lithium-ion batteries were recalled they overheated and were a potential fire hazard. Similar concerns caused Boeing to ground planes.Without adequate charge control and heat management, Li ion batteries are vulnerable to thermal runaway and pose significant safety issues. Should a Li ion cell container rupture and is exposed to moisture in the air, the ensuing chemical reaction will cause the materials within the battery to ignite. Such a chemical fire cannot be extinguished with water or conventional fire extinguishers. The electrolyte is also extremely toxic, which requires a special recycling/disposal facilities.Lithium is a rare earth material with limited supply subject to a high degree of price volatility.
Lead acid batteries over the years, they still suffer from three inherent issues:
- Corrosion and deterioration.
- low energy output per unit weight and volume.
Firefly now produces its own foam. With numerous recent technology and process advances, the manufacturing cost has dropped to less than 1% of the cost just five years ago. The life cycle cost of ownership of the Firefly battery is less than conventional lead acid batteries.
The Oasis battery (Group 31 size) is commercially available in 12v and 4 v models. These batteries use carbon foam negative plates. Larger format batteries are expected to be in production by the fourth quarter of 2015. Batteries with carbon foam positive plates will become available in 2016.
The Firefly batteries have four times the life and two time the energy density of a traditional lead acid battery:
- Plate corrosion is inhibited.
- Plates are resistant to the sulfation
- The high plate porosity allows the electrolyte to react more efficiently.
It absolutely is lead-acid chemistry. But the performance is superior to conventional flooded cell, AGM or VRLA lead acid battery.
Discharge efficiency is very efficient in lead-acid batteries, but charge efficiency declines rapidly above about 85% state-of-charge. Firefly batteries do use lead acid chemistry but, because they can operate indefinitely without ever being fully charged, there are some applications that can take advantage of cycling the batteries in the higher-efficiency, lower state-of-charge conditions.
Is it that important? There is a very significant difference in how the batteries should be charged and it is extremely important for the life of the battery. Overcharging gel and AGM batteries quickly leads to overheating which then drives battery degradation. Because both of these are VRLA (valve regulated lead acid) the do charge more efficiently and higher charges are not needed. Flooded batteries take a slightly higher voltage to fully charge and also to stir the liquid electrolyte from settling out (stratification). But flooded batteries are also less inclined to overheat.
PSOC (Partial-State-of-Charge) is the term used when a battery is not fully charged. Traditional leadacid batteries are particularly susceptible to permanent damage if left in these under-charged conditions for too long. The discharged material in the battery (sulfate crystals) will grow over time and eventually become too large to recharge. Firefly batteries are not sensitive to this crystal growth and can operate indefinitely in PSOC.