Are lead-acid batteries still competitive today?

9 月.04,2023

Yes, it is the answer. The earliest type of rechargeable battery is lead acid. Lead-acid batteries were the first commercially available rechargeable batteries, and they were created by French physician Gaston Planté in 1859. We still lack affordable alternatives to automobiles, wheelchairs, scooters, golf carts, and UPS systems 150 years later. To avoid sulfation, full saturation charging must be performed frequently, and the battery must always be charged. Sulfation will develop if the battery is kept drained and could prevent it from charging.

It’s crucial to determine the appropriate charging voltage limit. Positive plate grid corrosion brought on by high voltage (over 2.40V/cell) can limit battery lifetime while still producing good battery performance. The negative plate may sulfate as a result of low voltage restrictions. It won’t harm the battery if you keep it on float charge for a long time.

Deep cycling is not conducive to lead acid. A full discharge puts the battery under additional strain and reduces its lifespan with each cycle. Use of a bigger battery is advised to avoid the battery being overworked by frequent deep discharges. Although lead-acid batteries are less expensive than nickel-based systems, their operational costs can rise if repeated full cycles are needed.

Positive grid corrosion

Positive grid corrosion, active material depletion, and positive plate swelling are the main causes of its relatively low cycle life. Higher operating temperatures are where these effects are most noticeable. This trend will not be halted or reversed by cycling.

Additionally, performance is constrained at low temperatures. One of the best self-discharge rates among rechargeable batteries is 40% per year. Nickel-cadmium, however, self-discharges by that amount in just three months. Lead acid is not environmentally friendly due to its high lead content.

Plate thickness

The thickness of the positive plate can help determine a lead-acid battery’s service life. The lifespan increases with board thickness. The precipitates fall to the bottom as the lead on the plate gradually erodes during charging and discharging. A battery’s weight is a reliable measure of its lead concentration and lifespan.

A normal golf cart battery has a plate thickness of 0.07-0.11 inches (1.8-2.8 mm), but a car starter battery has a plate thickness of about 0.040 inches (1 mm). Batteries for forklifts may have plates that are larger than 0.250 inches (6 mm). Lead antimony plates are used in most industrial flooded deep cycle batteries. While increasing outgassing and water loss, this extends plate life.

Sealed lead acid

Researchers created a portable, maintenance-free lead-acid battery in the middle of the 1970s. The wetted separator is filled with the gelled liquid electrolyte, and the enclosure is then closed. Ventilation is made possible via safety valves during charging, discharging, and variations in ambient pressure.

Small sealed lead-acid systems (SLA), also known as Gelcell, and bigger valve-regulated lead-acid systems (VRLA), have both become popular due to varying market demands. The two batteries are comparable. The term “sealed lead-acid” may be regarded by engineers as misleading because no rechargeable battery can be totally sealed.

Because overcharging can result in gassing and water starvation, SLA and VRLA batteries are made with low overvoltage potential, unlike flooded lead-acid batteries. This prevents the battery from reaching its gassing potential during charging. Lead-calcium, rather than lead-antimony, is used in sealed lead-acid batteries to lessen dry-up.

Temperature

At 25°C (77°F), lead-acid batteries perform at their best. The lifespan will be shortened by rising temperatures. According to general rules, battery life is reduced by 50% for every 8°C (15°F) rise in temperature. When run at 25°C (77°F), VRLA lasts 10 years, but only 5 years when operated at 33°C (92°F). The same battery will stop working after 2.5 years if you put it in a constant desert temperature of 41°C (106°F).

The maximum discharge times for sealed lead-acid batteries are 5 hours (0.2C) and 20 hours (0.05C). Due to fewer losses, longer discharge periods will result in greater capacity measurements. High load currents are no match for lead acid’s performance.

(AGM) Absorbed Glass Mat Battery

AGM batteries feature absorbent glass mats between the plates and are a new breed of sealed lead-acid battery. It is sealed, requires no maintenance, and has rigidly attached plates that can bear a variety of shock and vibration. Almost no moisture is lost.

Like other lead-acid batteries, this one has the same charging voltage. Hydrogen emissions are below the 4% limit for aircraft and enclosed areas even in the case of severe overcharging. Long-term storage without recharging is possible because to the low self-discharge rate of 1-3% per month. Compared to flooded counterparts of the same capacity, AGMs are twice as expensive. AGM batteries, which are more durable than flooded batteries, are used in German performance vehicles.

Advantage

Cost-effective and easy to manufacture.
Proven, trustworthy, and well-recognized technology – Lead-acid batteries are incredibly robust and offer dependable service when used properly.
Among rechargeable battery systems, the self-discharge rate is the lowest.
High rate of discharge.

Limitation

Low energy density – Its employment is restricted to fixed and wheeled applications due to a poor weight-to-energy ratio.
Avoid storing the battery in a discharged state; the voltage must not go below 2.10V.
Limits the amount of complete discharges cycles allowed; this feature is perfect for standby applications that only sometimes need deep discharges.
The battery is not eco-friendly because of its electrolyte and lead concentration.
Submerged lead acid shipping limitations because spills pose a risk to the environment.
If charged incorrectly, thermal runaway could happen.

Conclusion

Although Lead acid batteries have many limitations, due to their price and stability, they still have a certain share in modern market. I just want to remind everyone that when purchasing batteries, you must choose a reliable lead-acid battery supplier.

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