Lead-acid battery
cycles[6] | |
Nominal cell voltage | 2.1 V[7] |
---|---|
Charge temperature interval | Min. −35°C, max. 45°C |
The lead-acid battery is a type of
As they are inexpensive compared to newer technologies, lead-acid batteries are widely used even when surge current is not important and other designs could provide higher energy densities. In 1999, lead-acid battery sales accounted for 40–50% of the value from batteries sold worldwide (excluding China and Russia), equivalent to a manufacturing market value of about US$15 billion.[8] Large-format lead-acid designs are widely used for storage in backup power supplies in cell phone towers, high-availability emergency power systems like hospitals, and stand-alone power systems. For these roles, modified versions of the standard cell may be used to improve storage times and reduce maintenance requirements. Gel-cells and absorbed glass-mat batteries are common in these roles, collectively known as VRLA (valve-regulated lead-acid) batteries.
In the charged state, the chemical energy of the battery is stored in the potential difference between metallic lead at the negative side and PbO2 on the positive side.
History
The French scientist Nicolas Gautherot observed in 1801 that wires that had been used for electrolysis experiments would themselves provide a small amount of "secondary" current after the main battery had been disconnected.[9] In 1859, Gaston Planté's lead-acid battery was the first battery that could be recharged by passing a reverse current through it. Planté's first model consisted of two lead sheets separated by rubber strips and rolled into a spiral.[10] His batteries were first used to power the lights in train carriages while stopped at a station. In 1881, Camille Alphonse Faure invented an improved version that consisted of a lead grid lattice, into which a lead oxide paste was pressed, forming a plate. This design was easier to mass-produce. An early manufacturer (from 1886) of lead-acid batteries was Henri Tudor.[citation needed]
Using a gel electrolyte instead of a liquid allows the battery to be used in different positions without leaking. Gel electrolyte batteries for any position were first used in the late 1920s, and in the 1930s, portable suitcase radio sets allowed the cell to be mounted vertically or horizontally (but not inverted) due to valve design.[11] In the 1970s, the valve-regulated lead-acid battery (VRLA, or "sealed") was developed, including modern absorbed glass mat (AGM) types, allowing operation in any position.
It was discovered early in 2011 that lead-acid batteries did in fact use some aspects of relativity to function, and to a lesser degree liquid metal and molten-salt batteries such as the Ca–Sb and Sn–Bi also use this effect.[12][13]
Electrochemistry
Discharge
In the discharged state, both the positive and negative plates become lead(II) sulfate (PbSO
4), and the electrolyte loses much of its dissolved sulfuric acid and becomes primarily water.
- Negative plate reaction
- Pb(s) + HSO−
4(aq) → PbSO
4(s) + H+
(aq) + 2e−
The release of two conduction electrons gives the lead electrode a negative charge.
As electrons accumulate, they create an electric field which attracts hydrogen ions and repels sulfate ions, leading to a double-layer near the surface. The hydrogen ions screen the charged electrode from the solution, which limits further reaction, unless charge is allowed to flow out of the electrode.
- Positive plate reaction
- PbO
2(s) + HSO−
4(aq) + 3H+
(aq) + 2e− → PbSO
4(s) + 2H
2O(l)
taking advantage of the metallic conductivity of PbO
2.
- The total reaction can be written as
- Pb(s) + PbO
2(s) + 2H
2SO
4(aq) → 2PbSO
4(s) + 2H
2O(l)
The net energy released per
Charging
In the fully-charged state, the negative plate consists of lead, and the positive plate is lead dioxide. The electrolyte solution has a higher concentration of aqueous sulfuric acid, which stores most of the chemical energy.
, which bubbles out and is lost. The design of some types of lead-acid battery allows the electrolyte level to be inspected and topped up with pure water to replace any that has been lost this way.Effect of charge level on freezing point
Because of freezing-point depression, the electrolyte is more likely to freeze in a cold environment when the battery has a low charge and a correspondingly low sulfuric acid concentration.
Ion motion
During discharge, H+
produced at the negative plates moves into the electrolyte solution and is then consumed at the positive plates, while HSO−
4 is consumed at both plates. The reverse occurs during the charge. This motion can be electrically-driven proton flow (the Grotthuss mechanism), or by diffusion through the medium, or by the flow of a liquid electrolyte medium. Since the electrolyte density is greater when the sulfuric acid concentration is higher, the liquid will tend to circulate by convection. Therefore, a liquid-medium cell tends to rapidly discharge and rapidly charge more efficiently than an otherwise-similar gel cell.
Measuring the charge level
Because the electrolyte takes part in the charge-discharge reaction, this battery has one major advantage over other chemistries: it is relatively simple to determine the state of charge by merely measuring the specific gravity of the electrolyte; the specific gravity falls as the battery discharges. Some battery designs include a simple hydrometer using colored floating balls of differing density. When used in diesel-electric submarines, the specific gravity was regularly measured and written on a blackboard in the control room to indicate how much longer the boat could remain submerged.[14]
The battery's open-circuit voltage can also be used to gauge the state of charge.[15] If the connections to the individual cells are accessible, then the state of charge of each cell can be determined which can provide a guide as to the state of health of the battery as a whole; otherwise, the overall battery voltage may be assessed.
Voltages for common usage
IUoU battery charging is a three-stage charging procedure for lead-acid batteries. A lead-acid battery's nominal voltage is 2.2 V for each cell. For a single cell, the voltage can range from 1.8 V loaded at full discharge, to 2.10 V in an open circuit at full charge.
Float voltage varies depending on battery type (flooded cells, gelled electrolyte, absorbed glass mat), and ranges from 1.8 V to 2.27 V. Equalization voltage, and charging voltage for sulfated cells, can range from 2.67 V to almost 3 V[16] (only until a charge current is flowing).[17][18] Specific values for a given battery depend on the design and manufacturer recommendations, and are usually given at a baseline temperature of 20 °C (68 °F), requiring adjustment for ambient conditions. IEEE Standard 485-2020 (first published in 1997) is the industry's recommended practice for sizing lead-acid batteries in stationary applications. [19]
Construction
Plates
The lead-acid cell can be demonstrated using sheet lead plates for the two electrodes. However, such a construction produces only around one ampere for roughly postcard-sized plates, and for only a few minutes.
Gaston Planté found a way to provide a much larger effective surface area. In Planté's design, the positive and negative plates were formed of two spirals of lead foil, separated with a sheet of cloth and coiled up. The cells initially had low capacity, so a slow process of "forming" was required to corrode the lead foils, creating lead dioxide on the plates and roughening them to increase surface area. Initially, this process used electricity from primary batteries; when generators became available after 1870, the cost of producing batteries greatly declined.[8] Planté plates are still used in some stationary applications, where the plates are mechanically grooved to increase their surface area.
In 1880, Camille Alphonse Faure patented a method of coating a lead grid (which serves as the current conductor) with a paste of lead oxides, sulfuric acid, and water, followed by curing phase in which the plates were exposed to gentle heat in a high-humidity environment. The curing process changed the paste into a mixture of lead sulfates which adhered to the lead plate. Then, during the battery's initial charge (called "formation"), the cured paste on the plates was converted into electrochemically active material (the "active mass"). Faure's process significantly reduced the time and cost to manufacture lead-acid batteries, and gave a substantial increase in capacity compared with Planté's battery.[20] Faure's method is still in use today, with only incremental improvements to paste composition, curing (which is still done with steam, but is now a very tightly controlled process), and structure and composition of the grid to which the paste is applied.
The grid developed by Faure was of pure lead with connecting rods of lead at right angles. In contrast, present-day grids are structured for improved mechanical strength and improved current flow. In addition to different grid patterns (ideally, all points on the plate are equidistant from the power conductor), modern-day processes also apply one or two thin fiberglass mats over the grid to distribute the weight more evenly. And while Faure had used pure lead for his grids, within a year (1881) these had been superseded by lead–antimony (8–12%) alloys to give the structures additional rigidity. However, high-antimony grids have higher hydrogen evolution (which also accelerates as the battery ages), and thus greater outgassing and higher maintenance costs. These issues were identified by U. B. Thomas and W. E. Haring at Bell Labs in the 1930s and eventually led to the development of lead–calcium grid alloys in 1935 for standby power batteries on the U.S. telephone network. Related research led to the development of lead–selenium grid alloys in Europe a few years later. Both lead–calcium and lead–selenium grid alloys still add antimony, albeit in much smaller quantities than the older high-antimony grids: lead–calcium grids have 4–6% antimony while lead–selenium grids have 1–2%. These metallurgical improvements give the grid more strength, which allows it to carry more weight, and therefore more active material, and so the plates can be thicker, which in turn contributes to battery lifespan since there is more material available to shed before the battery becomes unusable. High-antimony alloy grids are still used in batteries intended for frequent cycling, e.g. in motor-starting applications where frequent expansion/contraction of the plates need to be compensated for, but where outgassing is not significant since charge currents remain low. Since the 1950s, batteries designed for infrequent cycling applications (e.g., standby power batteries) increasingly have lead–calcium or lead–selenium alloy grids since these have less hydrogen evolution and thus lower maintenance overhead. Lead–calcium alloy grids are cheaper to manufacture (the cells thus have lower up-front costs), and have a lower self-discharge rate, and lower watering requirements, but have slightly poorer conductivity, are mechanically weaker (and thus require more antimony to compensate), and are more strongly subject to corrosion (and thus a shorter lifespan) than cells with lead–selenium alloy grids.
The open-circuit effect is a dramatic loss of battery cycle life, which was observed when calcium was substituted for antimony. It is also known as the antimony free effect.[21]
Modern approach
Modern-day paste contains
Once dry, the plates are stacked with suitable separators and inserted in a cell container. The alternate plates then constitute alternating positive and negative electrodes, and within the cell are later connected to one another (negative to negative, positive to positive) in parallel. The separators inhibit the plates from touching each other, which would otherwise constitute a short circuit. In flooded and gel cells, the separators are insulating rails or studs, formerly of glass or ceramic, and now of plastic. In AGM cells, the separator is the glass mat itself, and the rack of plates with separators are squeezed together before insertion into the cell; once in the cell, the glass mats expand slightly, effectively locking the plates in place. In multi-cell batteries, the cells are then connected to one another in series, either through connectors through the cell walls, or by a bridge over the cell walls. All intra-cell and inter-cell connections are of the same lead alloy as that used in the grids. This is necessary to prevent galvanic corrosion.
Deep-cycle batteries have a different geometry for their positive electrodes. The positive electrode is not a flat plate but a row of lead–oxide cylinders or tubes strung side by side, so their geometry is called tubular or cylindrical. The advantage of this is an increased surface area in contact with the electrolyte, with higher discharge and charge currents than a flat-plate cell of the same volume and depth-of-charge. Tubular-electrode cells have a higher power density than flat-plate cells. This makes tubular/cylindrical geometry plates especially suitable for high-current applications with weight or space limitations, such as for forklifts or for starting marine diesel engines. However, because tubes/cylinders have less active material in the same volume, they also have a lower energy density than flat-plate cells, and less active material at the electrode also means they have less material available to shed before the cell becomes unusable. Tubular/cylindrical electrodes are also more complicated to manufacture uniformly, which tends to make them more expensive than flat-plate cells. These trade-offs limit the range of applications in which tubular/cylindrical batteries are meaningful to situations where there is insufficient space to install higher-capacity (and thus larger) flat-plate units.
About 60% of the weight of an automotive-type lead-acid battery rated around 60 A·h is lead or internal parts made of lead; the balance is electrolyte, separators, and the case.[8] For example, there are approximately 8.7 kg (19 lb) of lead in a typical 14.5-kg (32 lb) battery.
Separators
An effective separator must possess a number of mechanical properties, including
Absorbent glass mat
In the absorbent glass mat (AGM) design, the separators between the plates are replaced by a
To reduce the water loss rate, calcium is alloyed with the plates; however, gas build-up remains a problem when the battery is deeply or rapidly charged or discharged. To prevent over-pressurization of the battery casing, AGM batteries include a one-way blow-off valve, and are often known as "valve-regulated lead-acid", or VRLA, designs.
Another advantage to the AGM design is that the electrolyte becomes the separator material and mechanically strong. This allows the plate stack to be compressed together in the battery shell, slightly increasing energy density compared to liquid or gel versions. AGM batteries often show a characteristic "bulging" in their shells when built in common rectangular shapes, due to the expansion of the positive plates.
The mat also prevents the vertical motion of the electrolyte within the battery. When a normal
While AGM cells do not permit watering (typically it is impossible to add water without drilling a hole in the battery), their recombination process is fundamentally limited by the usual chemical processes. Hydrogen gas will even diffuse right through the plastic case itself. Some have found that it is profitable to add water to an AGM battery, but this must be done slowly to allow for the water to mix throughout the battery via diffusion. When a lead-acid battery loses water, its acid concentration increases, increasing the corrosion rate of the plates significantly. AGM cells already have a high acid content in an attempt to lower the water loss rate and increase standby voltage, and this brings about shorter life compared to a lead–antimony flooded battery. If the open circuit voltage of AGM cells is significantly higher than 2.093 volts, or 12.56 V for a 12 V battery, then it has a higher acid content than a flooded cell; while this is normal for an AGM battery, it is not desirable for long life.
AGM cells that are intentionally or accidentally overcharged will show a higher open-circuit voltage according to the water lost (and acid concentration increased). One amp-hour of overcharge will electrolyse 0.335 grams of water per cell; some of this liberated hydrogen and oxygen will recombine, but not all of it.
Gelled electrolytes
During the 1970s, researchers developed the sealed version or
The only downside to the gel design is that the gel prevents rapid motion of the ions in the electrolyte, which reduces carrier mobility and thus surge current capability. For this reason, gel cells are most commonly found in energy storage applications like off-grid systems.
"Maintenance-free", "sealed", and "VRLA" (valve regulated lead acid)
Both gel and AGM designs are sealed, do not require watering, can be used in any orientation, and use a valve for gas blowoff. For this reason, both designs can be called maintenance-free, sealed, and VRLA. However, it is quite common to find resources stating that these terms refer to one or another of these designs, specifically.
In a valve regulated lead-acid (VRLA) battery, the hydrogen and oxygen produced in the cells largely recombine into water. Leakage is minimal, although some electrolyte still escapes if the recombination cannot keep up with gas evolution. Since VRLA batteries do not require (and make impossible) regular checking of the electrolyte level, they have been called maintenance-free batteries. However, this is somewhat of a misnomer: VRLA cells do require maintenance. As electrolyte is lost, VRLA cells "dry out" and lose capacity. This can be detected by taking regular internal
VRLA types became popular on motorcycles around 1983,[23] because the acid electrolyte is absorbed into the separator, so it cannot spill.[24] The separator also helps them better withstand vibration. They are also popular in stationary applications such as telecommunications sites, due to their small footprint and installation flexibility.[25]
Applications
Most of the world's lead-acid batteries are
Wet cell stand-by (stationary) batteries designed for deep discharge are commonly used in large backup power supplies for telephone and computer centres,
Portable batteries for miners' cap headlamps typically have two or three cells.[27]
Cycles
Starting batteries
Lead-acid batteries designed for starting automotive engines are not designed for deep discharge. They have a large number of thin plates designed for maximum surface area, and therefore maximum current output, which can easily be damaged by deep discharge. Repeated deep discharges will result in capacity loss and ultimately in premature failure, as the
Starting batteries are lighter than deep-cycle batteries of the same size, because the thinner and lighter cell plates do not extend all the way to the bottom of the battery case. This allows loose, disintegrated material to fall off the plates and collect at the bottom of the cell, prolonging the service life of the battery. If this loose debris rises enough, then it may touch the bottom of the plates and cause failure of a cell, resulting in loss of battery voltage and capacity.
Deep-cycle batteries
Specially-designed deep-cycle cells are much less susceptible to degradation due to cycling, and are required for applications where the batteries are regularly discharged, such as
Some batteries are designed as a compromise between starter (high-current) and deep cycle. They are able to be discharged to a greater degree than automotive batteries, but less so than deep-cycle batteries. They may be referred to as "marine/motorhome" batteries, or "leisure batteries".
Fast and slow charge and discharge
The capacity of a lead-acid battery is not a fixed quantity but varies according to how quickly it is discharged. The empirical relationship between discharge rate and capacity is known as Peukert's law.
When a battery is charged or discharged, only the reacting chemicals, which are at the interface between the electrodes and the electrolyte, are initially affected. With time, the charge stored in the chemicals at the interface, often called "interface charge" or "surface charge", spreads by diffusion of these chemicals throughout the volume of the active material.
Consider a battery that has been completely discharged (such as occurs when leaving the car lights on overnight, a current draw of about 6 amps). If it then is given a fast charge for only a few minutes, the battery plates charge only near the interface between the plates and the electrolyte. In this case the battery voltage might rise to a value near that of the charger voltage; this causes the charging current to decrease significantly. After a few hours this interface charge will spread to the volume of the electrode and electrolyte; this leads to an interface charge so low that it may be insufficient to start the car.[29] As long as the charging voltage stays below the gassing voltage (about 14.4 volts in a normal lead-acid battery), battery damage is unlikely, and in time the battery should return to a nominally charged state.
Sulfation and desulfation
This section needs additional citations for verification. (December 2013) |
Lead-acid batteries lose the ability to accept a charge when discharged for too long due to sulfation, the crystallization of
Sulfation occurs in lead-acid batteries when they are subjected to insufficient charging during normal operation. It impedes recharging; sulfate deposits ultimately expand, cracking the plates and destroying the battery. Eventually, so much of the battery plate area is unable to supply current that the battery capacity is greatly reduced. In addition, the sulfate portion (of the lead sulfate) is not returned to the electrolyte as sulfuric acid. It is believed that large crystals physically block the electrolyte from entering the pores of the plates. A white coating on the plates may be visible in batteries with clear cases or after dismantling the battery. Batteries that are sulfated show a high internal resistance and can deliver only a small fraction of normal discharge current. Sulfation also affects the charging cycle, resulting in longer charging times, less-efficient and incomplete charging, and higher battery temperatures.
SLI batteries (starting, lighting, ignition; e.g., car batteries) suffer the most deterioration because vehicles normally stand unused for relatively long periods of time. Deep-cycle and motive power batteries are subjected to regular controlled overcharging, eventually failing due to corrosion of the positive plate grids rather than sulfation.
Sulfation can be avoided if the battery is fully recharged immediately after a discharge cycle.[31] There are no known independently-verified ways to reverse sulfation.[8][32] There are commercial products claiming to achieve desulfation through various techniques such as pulse charging, but there are no peer-reviewed publications verifying their claims. Sulfation prevention remains the best course of action, by periodically fully charging the lead-acid batteries.
Stratification
A typical lead-acid battery contains a mixture with varying concentrations of water and acid. Sulfuric acid has a higher density than water, which causes the acid formed at the plates during charging to flow downward and collect at the bottom of the battery. Eventually the mixture will again reach uniform composition by diffusion, but this is a very slow process. Repeated cycles of partial charging and discharging will increase stratification of the electrolyte, reducing the capacity and performance of the battery because the lack of acid on top limits plate activation. The stratification also promotes corrosion on the upper half of the plates and sulfation at the bottom.[33]
Periodic overcharging creates gaseous reaction products at the plate, causing convection currents which mix the electrolyte and resolve the stratification. Mechanical stirring of the electrolyte would have the same effect. Batteries in moving vehicles are also subject to sloshing and splashing in the cells, as the vehicle accelerates, brakes, and turns.
Risk of explosion
Excessive charging causes electrolysis, emitting hydrogen and oxygen. This process is known as "gassing". Wet cells have open vents to release any gas produced, and VRLA batteries rely on valves fitted to each cell. Catalytic caps are available for flooded cells to recombine hydrogen and oxygen. A VRLA cell normally recombines any hydrogen and oxygen produced inside the cell, but malfunction or overheating may cause gas to build up. If this happens (for example, on overcharging), then the valve vents the gas and normalizes the pressure, producing a characteristic acidic smell. However, valves can fail, such as if dirt and debris accumulate, allowing pressure to build up.
Accumulated hydrogen and oxygen sometimes ignite in an internal explosion. The force of the explosion can cause the battery's casing to burst, or cause its top to fly off, spraying acid and casing fragments. An explosion in one cell may ignite any combustible gas mixture in the remaining cells. Similarly, in a poorly ventilated area, connecting or disconnecting a closed circuit (such as a load or a charger) to the battery terminals can also cause sparks and an explosion, if any gas was vented from the cells.
Individual cells within a battery can also short circuit, causing an explosion.
The cells of VRLA batteries typically swell when the internal pressure rises, thereby giving a warning to users and mechanics. The deformation varies from cell to cell, and is greatest at the ends where the walls are unsupported by other cells. Such over-pressurized batteries should be carefully isolated and discarded. Personnel working near batteries at risk of explosion should protect their eyes and exposed skin from burns due to spraying acid and fire by wearing a
Environment
Environmental concerns
According to a 2003 report entitled "Getting the Lead Out", by
Attempts are being made to develop alternatives (particularly for automotive use) because of concerns about the environmental consequences of improper disposal and of lead smelting operations, among other reasons. Alternatives are unlikely to displace them for applications such as engine starting or backup power systems, since the batteries, although heavy, are low-cost.
Recycling
According to the Battery Council, an industry group, lead-acid
Lead is highly toxic to humans, and recycling it can result in pollution and contamination of people, resulting in numerous and lasting health problems.[39][40] One ranking identifies lead-acid battery recycling as the world's most deadly industrial process, in terms of disability-adjusted life years lost—resulting in 2,000,000 to 4,800,000 estimated years of individual human life lost, globally.[41]
Lead-acid battery-recycling sites have themselves become a source of lead pollution, and by 1992, the EPA had selected 29 such sites for its Superfund clean-up, with 22 on its National Priority List.[38]
An effective pollution control system is a necessity to prevent lead emission. Continuous improvement in battery
Additives
Chemical additives have been used ever since the lead-acid battery became a commercial item, to reduce lead sulfate buildup on plates and improve battery condition when added to the electrolyte of a vented lead-acid battery. Such treatments are rarely, if ever, effective.[42]
Two compounds used for such purposes are
The active materials change physical form during charge/discharge, resulting in growth and distortion of the electrodes, and shedding of electrodes into the electrolyte. Once the active material has fallen out of the plates, it cannot be restored into position by any chemical treatment. Similarly, internal physical problems such as cracked plates, corroded connectors, or damaged separators cannot be restored chemically.
Corrosion problems
Corrosion of the external metal parts of the lead-acid battery results from a chemical reaction of the battery terminals, plugs, and connectors.
Corrosion on the positive terminal is caused by electrolysis, due to a mismatch of metal alloys used in the manufacture of the battery terminal and cable connector. White corrosion is usually lead or
If the battery is overfilled with water and electrolyte, then thermal expansion can force some of the liquid out of the battery vents onto the top of the battery. This solution can then react with the lead and other metals in the battery connector and cause corrosion.
The electrolyte can seep from the plastic-to-lead seal where the battery terminals penetrate the plastic case.
Acid fumes that vaporize through the vent caps, often caused by overcharging, and insufficient battery box ventilation can allow the sulfuric acid fumes to build up and react with the exposed metals.
See also
References
- ^ .
- ^ "Product Specification Guide" (PDF). Trojan Battery Company. 2008. Archived from the original (PDF) on 2013-06-04. Retrieved 2014-01-09.
- ^ Technical Manual: Sealed Lead Acid Batteries (PDF), Power-Sonic Corporation, 2018-12-17, p. 19, retrieved 2014-01-09
- ^ Cowie, Ivan (13 January 2014). "All About Batteries, Part 3: Lead-acid Batteries". UBM Canon. Retrieved 3 November 2015.
- ^ PS and PSG General Purpose Battery Specifications
- ^ PS Series - VRLA, AGM Battery, Valve Regulated
- ISBN 07506-4625-X.
- ^ ISBN 978-0-07-135978-8.
- ^ "Lead Acid Battery History".
- ^ "Gaston Planté (1834-1889)", Corrosion-doctors.org; Last accessed on Jan 3, 2007,
- ^ Camm, Frederick James. "Lead-acid battery". Wireless Constructor's Encyclopaedia (third ed.).
- ^ Schirber, Michael (2011-01-14). "Focus: Relativity Powers Your Car Battery". Physics. 27. American Physical Society. Retrieved 2019-12-25.
- ^ "Liquid Tin Bismuth Battery for Grid-Scale Energy Storage". InternationalTin.org. International Tin Association. 2018-01-09. Retrieved 2019-12-25.
- ISBN 978-1-57488-028-1.
- ^ "Deep Cycle Battery FAQ". WindSun.com. sec. "Battery voltages". Archived from the original on 2010-07-22. Retrieved 2010-06-30.
- ^ "Handbook for stationary lead-acid batteries Part 1: basics, design, operation modes and applications" (PDF). Edition 6. GNB Industrial Power, Exide Technologies. February 2012. Archived from the original (PDF) on January 18, 2020.
- ^ "Recommended voltage settings for 3 phase charging of flooded lead acid batteries.", Rolls Battery, Retrieved on 17 April 2015.
- ISBN 3-939359-11-4
- ^ "IEEE 485-2020 Standard".
- ISBN 978-0-85404-605-8.
- ^ "LABD". www.labatscience.com. Archived from the original on 2008-08-20.
- ^ United States Patent 5,948,567
- ]
- ^ Paper on recent VRLA developments from the Japanese Technical Center (SLI), Yuasa Corporation
- ^ EU Aviation News website Archived 2009-08-13 at the Wayback Machine tells about history, usage and recent developments for VRLA.
- ^ Introduction to Deep-Cycle Batteries in RE Systems
- ^ Cowlishaw, M.F. (December 1974). "The Characteristics and Use of Lead-acid Cap Lamps" (PDF). Trans. British Cave Research Association. 1 (4): 199–214.
- ^ ""Battery FAQ" at Northern Arizona Wind & Sun, visited 2006-07-23". Archived from the original on 2010-07-22. Retrieved 2006-07-23.
- ISBN 978-0-12-619455-5.
- ^ J W Simms. The Boy Electrician. George G Haerrap & Co. p. 65.
- ^
Equalize charging can prevent sulfation if performed prior to the lead sulfate forming crystals.
Broussely, Michel; Pistoia, Gianfranco, eds. (2007). Industrial applications of batteries: from cars to aerospace and energy storage. Elsevier. pp. 502–3. ISBN 978-0-444-52160-6.
- ^ "Sulfation Remedies Demystified". Batteryvitamin.net. Retrieved August 29, 2020.
- .
- ^
"2.3 LEAD DOSE-RESPONSE RELATIONSHIPS" (PDF), TOXICOLOGICAL PROFILE FOR LEAD, USA: CDC Agency for Toxic Substances and Disease Registry, August 2007, p. 31, retrieved 2013-09-26,
These data suggest that certain subtle neurobehavioral effects in children may occur at very low PbBs. (PbB means lead blood level)
- ISBN 978-0-918249-45-6.
- ^ "Battery Council International" (PDF). Battery Council. Retrieved 25 August 2020.
- Environmental Protection Agency, by Putnam, Hayes & Bartlett, Inc., Cambridge, Massachusetts, (also at nepis.epa.gov) retrieved May 15, 2021
- ^ Environmental Protection Agency, (also at: nepis.epa.gov) retrieved May 15, 2021
- The Lancet Planetary Health, of The Lancet, DOI:https://doi.org/10.1016/S2542-5196(20)30278-3•, as cited in "Pure Earth, USC and Macquarie University Publish Landmark Lead Study in The Lancet Planetary Health Journal," The Pollution Blog, Pure Earth, retrieved May 15, 2021
- ^ Pearce, Fred: "Getting the Lead Out: Why Battery Recycling Is a Global Health Hazard," November 2, 2020, Yale Environment 360, Yale School of the Environment, Yale University, retrieved May 15, 2021
- PMID 29892351.
- ^ http://museum.nist.gov/exhibits/adx2/partii.htm Archived 2016-03-14 at the Wayback Machine A dispute on battery additives when Dr. Vinal of the National Bureau of Standards reported on this for the National Better Business Bureau.
- ISBN 0-8376-0333-1.
External links
General
- magnalabs.com, battery plate sulfation
- reuk.co.uk, battery desulfation
- reuk.co.uk, lead acid batteries
- cbcdesign.co.uk, DC supply (April 2002)
- comcast.net, sme technical details on lead acid batteries
- btterycouncil.org (BCI), lead-acid battery manufacturers' trade organization.
- batteryfaq.org, car and deep-cycle battery FAQ
- atsdr.cdc.gov, lead (Pb) toxicity: key concepts | ATSDR - environmental medicine & environmental health education - CSEM case studies in environmental medicine (CSEM), agency for toxic substances and disease registry
- alton-moore.net, lead acid battery desulfator (Home Power #77 June/July 2000)]