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116-469: The Sinclair Zike is a portable bicycle with a small electric motor driving the rear wheel and with batteries built into its frame. It weighs 11 kg (24 lb). The batteries fit inside the central shaft together with the motor. The two-wheeler utilizes nickel–cadmium batteries , which weigh half as much as the typical lead–acid batteries used in 20th-century electric vehicles and can withstand 2000 recharging cycles. A three-position throttle placed under

232-512: A " memory effect " if they are discharged and recharged to the same state of charge hundreds of times. The apparent symptom is that the battery "remembers" the point in its discharge cycle where recharging began and during subsequent use suffers a sudden drop in voltage at that point, as if the battery had been discharged. The capacity of the battery is not actually reduced substantially. Some electronics designed to be powered by Ni–Cd batteries are able to withstand this reduced voltage long enough for

348-419: A 4C or 6C charge rate, but this is very uncommon. It also greatly increases the risk of the cells overheating and venting due to an internal over-pressure condition: the cell's rate of temperature rise is governed by its internal resistance and the square of the charging rate. At a 4C rate, the amount of heat generated in the cell is sixteen times higher than the heat at the 1C rate. The downside to faster charging

464-404: A battery is constant current charged at 1 CA rate until all the cells have reached at least 1.55   V. Another charge cycle follows at 0.1 CA rate, again until all cells have reached 1.55   V. The charge is finished with an equalizing or top-up charge, typically for not less than 4 hours at 0.1 CA rate. The purpose of the over-charge is to expel as much (if not all) of the gases collected on

580-459: 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,

696-461: A charge current is flowing). 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. The lead–acid cell can be demonstrated using sheet lead plates for

812-401: A cool, dry environment. Sealed Ni–Cd cells consist of a pressure vessel that is supposed to contain any generation of oxygen and hydrogen gases until they can recombine back to water. Such generation typically occurs during rapid charge and discharge, and exceedingly at overcharge condition. If the pressure exceeds the limit of the safety valve, water in the form of gas is lost. Since the vessel

928-510: A current equal to one tenth the ampere-hour rating (C/10) for 14–16 hours; that is, a 100 mAh battery takes 10 mA for 14 hours, for a total of 140 mAh to charge at this rate. At the rapid-charge rate, done at 100% of the rated capacity of the battery in 1 hour (1C), the battery holds roughly 80% of the charge, so a 100 mAh battery takes 125 mAh to charge (that is, approximately 1 hour and fifteen minutes). Some specialized batteries can be charged in as little as 10–15 minutes at

1044-429: 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. taking advantage of the metallic conductivity of PbO 2 . The net energy released per mole (207 g) of Pb(s) converted to PbSO 4 (s) is approximately 400 kJ, corresponding to the formation of 36 g of water. The sum of

1160-596: A fair capacity but their significant advantage is the ability to deliver practically their full rated capacity at high discharge rates (discharging in one hour or less). However, the materials are more costly than that of the lead–acid battery , and the cells have high self-discharge rates. Sealed Ni–Cd cells were at one time widely used in portable power tools, photography equipment, flashlights , emergency lighting, hobby RC , and portable electronic devices. The superior capacity of nickel–metal hydride batteries , and recent lower cost, has largely supplanted Ni–Cd use. Further,

1276-441: A favourable choice for remote-controlled electric model airplanes, boats, and cars, as well as cordless power tools and camera flash units. Advances in battery-manufacturing technologies throughout the second half of the twentieth century have made batteries increasingly cheaper to produce. Battery-powered devices in general have increased in popularity. As of 2000, about 1.5 billion Ni–Cd batteries were produced annually. Up until

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1392-573: A floating battery electrical system the regulator voltage is set to charge the battery at constant potential charge (typically 14 or 28   V). If this voltage is set too high it will result in rapid electrolyte loss. A failed charge regulator may allow the charge voltage to rise well above this value, causing a massive overcharge with boiling over of the electrolyte. Most of the uses described below are shown for historical purposes, as sealed (portable) Ni-Cd batteries have progressively been displaced by higher performance Li-ion cells, and their placing on

1508-420: 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. During

1624-427: A high rate or recharged at a higher than nominal rate. This also means the electrolyte lost during venting must be periodically replaced through routine maintenance. Depending on the charge–discharge cycles and type of battery this can mean a maintenance period of anything from a few months to a year. Vented-cell voltage rises rapidly at the end of charge allowing for very simple charger circuitry to be used. Typically

1740-503: A hundred amps or so from specially constructed Ni–Cd batteries, which are used to drive main motors. 5–6 minutes of model operation is easily achievable from quite small batteries, so a reasonably high power-to-weight figure is achieved, comparable to internal combustion motors, though of lesser duration. In this, however, they have been largely superseded by lithium polymer (LiPo) and lithium iron phosphate (LiFe) batteries, which can provide even higher energy densities. Ni–Cd cells have

1856-569: A lesser degree liquid metal and molten-salt batteries such as the Ca–Sb and Sn–Bi also use this effect. 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. 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

1972-493: A long period and then used and recharged. The mat significantly prevents this stratification, eliminating the need to periodically shake the batteries, boil them, or run an equalization charge through them to mix the electrolyte. Stratification also causes the upper layers of the battery to become almost completely water, which can freeze in cold weather; AGMs are significantly less susceptible to damage due to low-temperature use. While AGM cells do not permit watering (typically it

2088-421: 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

2204-416: 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

2320-555: A nominal cell potential of 1.2 volts (V). This is lower than the 1.5 V of alkaline and zinc–carbon primary cells, and consequently they are not appropriate as a replacement in all applications. However, the 1.5 V of a primary alkaline cell refers to its initial, rather than average, voltage. Unlike alkaline and zinc–carbon primary cells, a Ni–Cd cell's terminal voltage only changes a little as it discharges. Because many electronic devices are designed to work with primary cells that may discharge to as low as 0.90 to 1.0 V per cell,

2436-496: A porous nickel-plated electrode and fifteen years later work began on a sealed nickel–cadmium battery. The first production in the United States began in 1946. Up to this point, the batteries were "pocket type," constructed of nickel-plated steel pockets containing nickel and cadmium active materials. Around the middle of the twentieth century, sintered -plate Ni–Cd batteries became increasingly popular. Fusing nickel powder at

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2552-400: A sealing plate equipped with a self-sealing safety valve . The positive and negative electrode plates, isolated from each other by the separator, are rolled in a spiral shape inside the case. This is known as the jelly-roll design and allows a Ni–Cd cell to deliver a much higher maximum current than an equivalent size alkaline cell. Alkaline cells have a bobbin construction where the cell casing

2668-403: 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 (only until

2784-491: 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. 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

2900-406: A small amount of secondary current after the main battery had been disconnected. 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. His batteries were first used to power the lights in train carriages while stopped at

3016-467: 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 . 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

3132-425: A temperature well below its melting point using high pressures creates sintered plates. The plates thus formed are highly porous, about 80 percent by volume. Positive and negative plates are produced by soaking the nickel plates in nickel- and cadmium-active materials, respectively. Sintered plates are usually much thinner than the pocket type, resulting in greater surface area per volume and higher currents. In general,

3248-508: A terminal voltage during discharge of around 1.2 volts which decreases little until nearly the end of discharge. The maximum electromotive force offered by a Ni–Cd cell is 1.3   V. Ni–Cd batteries are made in a wide range of sizes and capacities, from portable sealed types interchangeable with carbon–zinc dry cells, to large ventilated cells used for standby power and motive power. Compared with other types of rechargeable cells they offer good cycle life and performance at low temperatures with

3364-419: 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

3480-808: A vent or low pressure release valve that releases any generated oxygen and hydrogen gases when overcharged or discharged rapidly. Since the battery is not a pressure vessel , it is safer, weighs less, and has a simpler and more economical structure. This also means the battery is not normally damaged by excessive rates of overcharge, discharge or even negative charge. They are used in aviation, rail and mass transit, backup power for telecoms, engine starting for backup turbines etc. Using vented-cell Ni–Cd batteries results in reduction in size, weight and maintenance requirements over other types of batteries. Vented-cell Ni–Cd batteries have long lives (up to 20 years or more, depending on type) and operate at extreme temperatures (from −40 to 70 °C). A steel battery box contains

3596-401: 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

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3712-603: Is a toxic heavy metal and therefore requires special care during battery disposal. In the United States , the expected battery recycling cost (to be used for proper disposal at the end of the service lifetime) is rolled into the battery purchase price. Under the so-called "batteries directive" ( 2006/66/EC ), the sale of consumer Ni–Cd batteries has now been banned within the European Union except for medical use; alarm systems; emergency lighting; and portable power tools. This last category has been banned effective 2016. Under

3828-437: Is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes . The abbreviation Ni–Cd is derived from the chemical symbols of nickel (Ni) and cadmium (Cd): the abbreviation NiCad is a registered trademark of SAFT Corporation , although this brand name is commonly used to describe all Ni–Cd batteries. Wet-cell nickel–cadmium batteries were invented in 1899. A Ni–Cd battery has

3944-425: Is also known as the antimony free effect. Modern-day paste contains carbon black , blanc fixe ( barium sulfate ), and lignosulfonate . The blanc fixe acts as a seed crystal for the lead–to– lead-sulfate reaction. The blanc fixe must be fully dispersed in the paste in order for it to be effective. The lignosulfonate prevents the negative plate from forming a solid mass during the discharge cycle, instead enabling

4060-411: Is designed to contain an exact amount of electrolyte this loss will rapidly affect the capacity of the cell and its ability to receive and deliver current. To detect all conditions of overcharge demands great sophistication from the charging circuit and a cheap charger will eventually damage even the best quality cells. A fully charged Ni–Cd cell contains: Ni–Cd batteries usually have a metal case with

4176-431: Is filled with electrolyte and contains a graphite rod which acts as the positive electrode. As a relatively small area of the electrode is in contact with the electrolyte (as opposed to the jelly-roll design), the internal resistance for an equivalent sized alkaline cell is higher which limits the maximum current that can be delivered. The chemical reactions at the cadmium electrode during discharge are: The reactions at

4292-401: 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. 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

4408-494: Is important, Ni–Cd batteries are now at a disadvantage compared with nickel–metal hydride and lithium-ion batteries. However, the Ni–Cd battery is still very useful in applications requiring very high discharge rates because it can endure such discharge with no damage or loss of capacity. When compared to other forms of rechargeable battery, the Ni–Cd battery has a number of distinct advantages: The primary trade-off with Ni–Cd batteries

4524-473: 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

4640-409: 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. For example, there are approximately 8.7 kilograms (19 lb) of lead in a typical 14.5-kilogram (32 lb) battery. Separators between

4756-455: Is lost. The design of some types of lead–acid battery (eg "flooded", but not VRLA (AGM or gel) ) allows the electrolyte level to be inspected and topped up with pure water to replace any that has been lost this way. 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. During discharge, H produced at

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4872-458: Is mostly used in automotive and heavy-duty industrial applications. For portable applications, the number of cells is normally below 18 cells (24 V). Industrial-sized flooded batteries are available with capacities ranging from 12.5 Ah up to several hundred Ah. Recently, nickel–metal hydride and lithium-ion batteries have become commercially available and cheaper, the former type now rivaling Ni–Cd batteries in cost. Where energy density

4988-583: Is possible. Gel cells also have lower freezing and higher boiling points than the liquid electrolytes used in conventional wet cells and AGMs, which makes them suitable for use in extreme conditions. 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. Both gel and AGM designs are sealed, do not require watering, can be used in any orientation, and use

5104-455: Is required. Maintenance procedures have recently been developed allowing rehydration, often restoring significant amounts of lost capacity. VRLA types became popular on motorcycles around 1983, because the separator improves resistance to vibration and prevents the acid electrolyte from spilling. They are also popular in stationary applications such as telecommunications sites, due to their small footprint and installation flexibility. Most of

5220-645: Is the addition of lithium hydroxide to the potassium hydroxide electrolyte. This was believed to prolong the service life by making the cell more resistant to electrical abuse. The Ni–Cd battery in its modern form is extremely resistant to electrical abuse anyway, so this practice has been discontinued. Larger flooded cells are used for aircraft starting batteries , standby power and marginally in electric vehicles , Vented-cell ( wet cell , flooded cell ) Ni–Cd batteries are used when large capacities and high discharge rates are required. Unlike typical Ni–Cd cells, which are sealed (see next section), vented cells have

5336-422: Is the higher risk of overcharging , which can damage the battery. and the increased temperatures the cell has to endure (which potentially shortens its life). The safe temperature range when in use is between −20 °C and 45 °C. During charging, the battery temperature typically stays low, around the same as the ambient temperature (the charging reaction absorbs energy), but as the battery nears full charge

5452-479: Is their higher cost and the use of cadmium. This heavy metal is an environmental hazard, and is highly toxic to all higher forms of life. They are also more costly than lead–acid batteries because nickel and cadmium cost more. One of the biggest disadvantages is that the battery exhibits a very marked negative temperature coefficient. This means that as the cell temperature rises, the internal resistance falls. This can pose considerable charging problems, particularly with

5568-577: The electric motors in diesel–electric (conventional) submarines when submerged, and are used as emergency power on nuclear submarines as well. Valve-regulated lead–acid batteries cannot spill their electrolyte. They are used in back-up power supplies for alarm and smaller computer systems (particularly in uninterruptible power supplies ) and for electric scooters , electric wheelchairs , electrified bicycles , marine applications, battery electric vehicles or micro hybrid vehicles , and motorcycles. Many electric forklifts use lead–acid batteries, where

5684-426: The electrodes disintegrate due to mechanical stresses that arise from cycling. Starting batteries kept on a continuous float charge will suffer corrosion of the electrodes which will also result in premature failure. Starting batteries should therefore be kept open circuit but charged regularly (at least once every two weeks) to prevent sulfation . Starting batteries are lighter than deep-cycle batteries of

5800-460: 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. The battery's open-circuit voltage can also be used to gauge

5916-538: The 1970s, researchers developed the sealed version or gel battery , which mixes a silica gelling agent into the electrolyte ( silica-gel -based lead–acid batteries used in portable radios from the early 1930s were not fully sealed). This converts the formerly liquid interior of the cells into a semi-stiff paste, providing many of the same advantages of the AGM. Such designs are even less susceptible to evaporation and are often used in situations where little or no periodic maintenance

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6032-420: The AGM design is that the electrolyte becomes the separator material and is 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

6148-473: The EU market has, for the most part, been prohibited since 2006 by the 2006/66/EC EU Batteries Directive. Sealed Ni–Cd cells were used individually, or assembled into battery packs containing two or more cells. Small cells are used for portable electronics and toys (such as solar garden lights), often using cells manufactured in the same sizes as primary cells . When Ni–Cd batteries are substituted for primary cells,

6264-448: The Earth over a period of several years. After this time, it was found that the capacities of the batteries had declined significantly, but were still fit for use. It is unlikely that this precise repetitive charging (for example, 1,000 charges/discharges with less than 2% variability) could ever be reproduced by individuals using electrical goods. The original paper describing the memory effect

6380-538: The NiCad batteries have substantially lower self-discharge, on the order of 1% or 2% per month. It is possible to perform a trickle charge at current levels just high enough to offset this discharge rate; to keep a battery fully charged. However, if the battery is going to be stored unused for a long period of time, it should be discharged down to at most 40% of capacity (some manufacturers recommend fully discharging and even short-circuiting once fully discharged ), and stored in

6496-719: The Zike and that had reasonable success but it hit a snag because the company that was making it for us, on a sub-contract basis, turned out to be a subsidiary of a German company and the German owners came in and closed the whole thing down. Very, very sad.” The reviews for the Zike in the British press were somewhat negative (possibly in part due to memories of the C5 which preceded it). Susan Watts for The Independent called it "an impressive feat of miniaturisation" but stated that "a quick test ride suggested

6612-459: The Zike is too unstable and lacking in power to make a cyclist feel secure on the nightmarish roads of London." Similarly Nik Berg for Auto Express noted that the Zike was lightweight and portable, but expressed concern about the lack of power and stated that "potholes should be avoided at all costs—the tiny wheels just get swallowed." Nickel%E2%80%93cadmium battery The nickel–cadmium battery ( Ni–Cd battery or NiCad battery )

6728-432: The batteries are regularly discharged, such as photovoltaic systems, electric vehicles ( forklift , golf cart , electric cars , and others), and uninterruptible power supplies . These batteries have thicker plates that cannot deliver as much peak current but can withstand frequent discharging. Some batteries are designed as a compromise between starter (high-current) and deep cycle. They are able to be discharged to

6844-555: 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

6960-509: The battery can be installed in any orientation, though if it is installed upside down, then acid may be blown out through the overpressure vent. 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 ( VRLA ) designs. Another advantage to

7076-418: The battery is punctured, the electrolyte will not flow out of the mats. The principal purpose of replacing liquid electrolyte in a flooded battery with a semi-saturated fiberglass mat is to substantially increase the gas transport through the separator; hydrogen or oxygen gas produced during overcharge or charge (if the charge current is excessive) is able to freely pass through the glass mat and reduce or oxidize

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7192-592: The cadmium in varying quantities, but found the iron formulations to be wanting. Jungner's work was largely unknown in the United States. Thomas Edison patented a nickel– or cobalt–cadmium battery in 1902, and adapted the battery design when he introduced the nickel–iron battery to the US two years after Jungner had built one. In 1906, Jungner established a factory close to Oskarshamn, Sweden, to produce flooded design Ni–Cd batteries. In 1932, active materials were deposited inside

7308-430: The cell was manufactured. The charge rate is measured based on the percentage of the amp-hour capacity the battery is fed as a steady current over the duration of the charge. Regardless of the charge speed, more energy must be supplied to the battery than its actual capacity, to account for energy loss during charging, with faster charges being more efficient. For example, an "overnight" charge, might consist of supplying

7424-476: The cells connected in series to gain the desired voltage (1.2 V per cell nominal). Cells are usually made of a light and durable polyamide ( nylon ), with multiple nickel–cadmium plates welded together for each electrode inside. A separator or liner made of silicone rubber acts as an insulator and a gas barrier between the electrodes. Cells are flooded with an electrolyte of 30% aqueous solution of potassium hydroxide ( KOH ). The specific gravity of

7540-406: 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

7656-494: The electrodes, hydrogen on the negative and oxygen on the positive, and some of these gases recombine to form water which in turn will raise the electrolyte level to its highest level after which it is safe to adjust the electrolyte levels. During the over-charge or top-up charge, the cell voltages will go beyond 1.6 V and then slowly start to drop. No cell should rise above 1.71   V (dry cell) or drop below 1.55   V (gas barrier broken). In an aircraft installation with

7772-420: The electrolyte does not indicate if the battery is discharged or fully charged but changes mainly with evaporation of water. The top of the cell contains a space for excess electrolyte and a pressure release vent. Large nickel-plated copper studs and thick interconnecting links assure minimum equivalent series resistance for the battery. The venting of gases means that the battery is either being discharged at

7888-438: 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 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 cylinders have less active material in

8004-463: The environmental impact of the disposal of the toxic metal cadmium has contributed considerably to the reduction in their use. Within the European Union, Ni–Cd batteries can now only be supplied for replacement purposes or for certain types of new equipment such as medical devices. Larger ventilated wet cell Ni–Cd batteries are used in emergency lighting, standby power, and uninterruptible power supplies and other applications. The first Ni–Cd battery

8120-425: The formation of long needle–like dendrites . The long crystals have more surface area and are easily converted back to the original state on charging. Carbon black counteracts the effect of inhibiting formation caused by the lignosulfonates. Sulfonated naphthalene condensate dispersant is a more effective expander than lignosulfonate and speeds up formation. This dispersant improves the dispersion of barium sulfate in

8236-500: The greater amount of reactive material surface area in a battery, the lower its internal resistance . Since the 2000s, all consumer Ni–Cd batteries use the jelly-roll configuration. The maximum discharge rate for a Ni–Cd battery varies by size. For a common AA-size cell, the maximum discharge rate is approximately 1.8 amperes; for a D size battery the discharge rate can be as high as 3.5 amperes. Model-aircraft or -boat builders often take much larger currents of up to

8352-507: The high current required by starter motors . Lead–acid batteries suffer from relatively short cycle lifespan (usually less than 500 deep cycles) and overall lifespan (due to the double sulfation in the discharged state), as well as long charging times. As they are not expensive 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

8468-463: 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. In the 1970s, the valve-regulated lead–acid ( VRLA ), or sealed , battery was developed, including modern absorbed glass mat ( AGM ) types, allowing operation in any position. It was discovered early in 2011 that lead–acid batteries do in fact use some aspects of relativity to function, and to

8584-485: The lower terminal voltage and smaller ampere-hour capacity may reduce performance as compared to primary cells. Miniature button cells are sometimes used in photographic equipment, hand-held lamps (flashlight or torch), computer-memory standby, toys, and novelties. Specialty Ni–Cd batteries were used in cordless and wireless telephones, emergency lighting, and other applications. With a relatively low internal resistance , they can supply high surge currents . This makes them

8700-414: The mass of the water and other constituent parts. 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. Overcharging with high charging voltages generates oxygen and hydrogen gas by electrolysis of water , which bubbles out and

8816-425: The memory effect is the so-called voltage depression or lazy battery effect . This results from repeated overcharging; the symptom is that the battery appears to be fully charged but discharges quickly after only a brief period of operation. In rare cases, much of the lost capacity can be recovered by a few deep-discharge cycles, a function often provided by automatic battery chargers. However, this process may reduce

8932-580: The mid-1990s, Ni–Cd batteries had an overwhelming majority of the market share for rechargeable batteries in home electronics. At one point, Ni–Cd batteries accounted for 8% of all portable secondary (rechargeable) battery sales in the EU, and in the UK for 9.2% (disposal) and in Switzerland for 1.3% of all portable battery sales. In the EU the 2006 Battery Directive restricted sales of Ni–Cd batteries to consumers for portable devices. Ni–Cd cells are available in

9048-428: The molecular masses of the reactants is 642.6 g/mole, so theoretically a cell can produce two faradays of charge (192,971 coulombs ) from 642.6 g of reactants, or 83.4 ampere-hours per kilogram for a 2-volt cell (or 13.9 ampere-hours per kilogram for a 12-volt battery). This comes to 167 watt-hours per kilogram of reactants, but in practice, a lead–acid cell gives only 30–40 watt-hours per kilogram of battery, due to

9164-481: 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

9280-408: The negative. It was not until later that pure cadmium metal and nickel hydroxide were used. Until about 1960, the chemical reaction was not completely understood. There were several speculations as to the reaction products. The debate was finally resolved by infrared spectroscopy , which revealed cadmium hydroxide and nickel hydroxide. Another historically important variation on the basic Ni–Cd cell

9396-439: The nickel oxide electrode are: The net reaction during discharge is During recharge, the reactions go from right to left. The alkaline electrolyte (commonly KOH) is not consumed in this reaction and therefore its specific gravity , unlike in lead–acid batteries, is not a guide to its state of charge. When Jungner built the first Ni–Cd batteries, he used nickel oxide in the positive electrode, and iron and cadmium materials in

9512-566: 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

9628-448: The opposing plate, respectively. In a flooded cell, the bubbles of gas float to the top of the battery and are lost to the atmosphere. This mechanism for the gas produced to recombine and the additional benefit of a semi-saturated cell providing no substantial leakage of electrolyte upon physical puncture of the battery case allows the battery to be completely sealed, which makes them useful in portable devices and similar roles. Additionally,

9744-440: The original choice, but it deteriorates in the acid electrolyte. An effective separator must possess a number of mechanical properties, including permeability , porosity, pore size distribution, specific surface area , mechanical design and strength, electrical resistance , ionic conductivity , and chemical compatibility with the electrolyte. In service, the separator must have good resistance to acid and oxidation . The area of

9860-411: The over-current cut-out operated or the battery destroyed itself. This is the principal factor that prevents its use as engine-starting batteries. Today with alternator-based charging systems with solid-state regulators, the construction of a suitable charging system would be relatively simple, but the car manufacturers are reluctant to abandon tried-and-tested technology. Ni–Cd batteries may suffer from

9976-428: The paste, reduces hydroset time, produces a more breakage-resistant plate, reduces fine lead particles, and thereby improves handling and pasting characteristics. It extends battery life by increasing end-of-charge voltage. Sulfonated naphthalene requires about one-third to one-half the amount of lignosulfonate and is stable to higher temperatures. Once dry, the plates are stacked with suitable separators and inserted in

10092-459: 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

10208-399: 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. 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

10324-401: The positive and negative plates prevent short circuits through physical contact, mostly through dendrites ( treeing ), but also through shedding of the active material. Separators allow the flow of ions between the plates of an electrochemical cell to form a closed circuit. Wood, rubber, glass fiber mat, cellulose , and PVC or polyethylene plastic have been used to make separators. Wood was

10440-399: 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

10556-519: 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 resistance , conductance , or impedance measurements. Regular testing reveals whether more involved testing and maintenance

10672-405: The relatively simple charging systems employed for lead–acid type batteries. Whilst lead–acid batteries can be charged by simply connecting a dynamo to them, with a simple electromagnetic cut-out system for when the dynamo is stationary or an over-current occurs, the Ni–Cd battery under a similar charging scheme would exhibit thermal runaway, where the charging current would continue to rise until

10788-587: The relatively steady 1.2 V of a Ni–Cd cell is enough to allow operation. Some would consider the near-constant voltage a drawback as it makes it difficult to detect when the battery charge is low. Ni–Cd batteries used to replace 9 V batteries usually only have six cells, for a terminal voltage of 7.2 volts. While most pocket radios will operate satisfactorily at this voltage, some manufacturers such as Varta made 8.4 volt batteries with seven cells for more critical applications. Ni–Cd batteries can be charged at several different rates, depending on how

10904-489: The right handlebar varies the electric power and thus the amount of pedaling required to keep going, although the Zike has only one gear. Battery life is said to be between 30 minutes and three hours depending on which of the three running speeds are used. The batteries can be fully recharged by plugging them into the mains for just one hour, and they are also recharged regeneratively using the energy from pedalling, freewheeling, and braking. The bicycle's maximum self-powered speed

11020-619: The same EU directive, used industrial Ni–Cd batteries must be collected by their producers in order to be recycled in dedicated facilities. Lead%E2%80%93acid battery The lead–acid battery is a type of rechargeable battery first invented in 1859 by French physicist Gaston Planté . It is the first type of rechargeable battery ever created. Compared to modern rechargeable batteries, lead–acid batteries have relatively low energy density . Despite this, they are able to supply high surge currents . These features, along with their low cost, make them attractive for use in motor vehicles to provide

11136-409: 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

11252-560: 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. Specially-designed deep-cycle cells are much less susceptible to degradation due to cycling, and are required for applications where

11368-676: The same sizes as alkaline batteries , from AAA through D, as well as several multi-cell sizes, including the equivalent of a 9-volt battery. A fully charged single Ni–Cd cell, under no load, carries a potential difference of between 1.25 and 1.35 volts, which stays relatively constant as the battery is discharged. Since an alkaline battery near fully discharged may see its voltage drop to as low as 0.9 volts, Ni–Cd cells and alkaline cells are typically interchangeable for most applications. In addition to single cells, batteries exist that contain up to 300 cells (nominally 360 volts, actual voltage under no load between 380 and 420 volts). This multi-cell design

11484-486: The same volume, they also have lower energy densities than otherwise comparable flat-plate cells, and less active material at the electrode also means they have less material available to shed before the cells become unusable. 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 cylindrical batteries are meaningful to situations where there

11600-437: 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

11716-405: The separator must be a little larger than the area of the plates to prevent material shorting between the plates. The separators must remain stable over the battery's operating temperature range. In the absorbent glass mat ( AGM ) design, the separators between the plates are replaced by a glass fibre mat soaked in electrolyte. There is only enough electrolyte in the mat to keep it wet, and if

11832-411: The shelf life of the battery. If treated well, a Ni–Cd battery can last for 1,000 cycles or more before its capacity drops below half its original capacity. Many home chargers claim to be "smart chargers" which will shut down and not damage the battery, but this seems to be a common problem. Ni–Cd batteries contain between 6% (for industrial batteries) and 18% (for commercial batteries) cadmium , which

11948-547: 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 valve-regulated lead–acid ( VRLA ) batteries . When charged, the battery's chemical energy is stored in the potential difference between metallic lead at the negative side and PbO 2 on the positive side. The French scientist Nicolas Gautherot observed in 1801 that wires that had been used for electrolysis experiments would themselves provide

12064-429: The state of charge. 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. 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

12180-505: The temperature will rise to 45–50 °C. Some battery chargers detect this temperature increase to cut off charging and prevent over-charging. When not under load or charge, a Ni–Cd battery will self-discharge approximately 10% per month at 20 °C, ranging up to 20% per month at higher temperatures. Note; year 2022, the preceding sentence was certainly true when NiCad was introduced and even 50 years ago. However continued improvements seen around 40 years ago lead to 5% per month and today

12296-402: 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

12412-417: The value from batteries sold worldwide (excluding China and Russia), equivalent to a manufacturing market value of about US$ 15 billion . Large-format lead–acid designs are widely used for storage in backup power supplies in telecommunications networks such as for cell sites , high-availability emergency power systems as used in hospitals, and stand-alone power systems . For these roles, modified versions of

12528-458: The vertical motion of the electrolyte within the battery. When a normal wet cell is stored in a discharged state, the heavier acid molecules tend to settle to the bottom of the battery, causing the electrolyte to stratify. When the battery is then used, the majority of the current flows only in this area, and the bottom of the plates tends to wear out rapidly. This is one of the reasons a conventional car battery can be ruined by leaving it stored for

12644-418: The voltage to return to normal. However, if the device is unable to operate through this period of decreased voltage, it will be unable to get enough energy out of the battery, and for all practical purposes, the battery appears "dead" earlier than normal. There is evidence that the memory effect story originated from orbiting satellites, where they were similarly charging and discharging with every orbit around

12760-626: The weight is used as part of a counterweight. Lead–acid batteries were used to supply the filament (heater) voltage, with 2 V common in early vacuum tube (valve) radio receivers. Portable batteries for miners' cap headlamps typically have two or three cells. 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

12876-712: The world's lead–acid batteries are automobile starting, lighting, and ignition (SLI) batteries, with an estimated 320 million units shipped in 1999. In 1992 about 3 million tons of lead were used in the manufacture of batteries. Wet cell stand-by (stationary) batteries designed for deep discharge are commonly used in large backup power supplies for telephone and computer centres, grid energy storage , and off-grid household electric power systems. Lead–acid batteries are used in emergency lighting and to power sump pumps in case of power failure . Traction (propulsion) batteries are used in golf carts and other battery electric vehicles . Large lead–acid batteries are also used to power

12992-399: Was created by Waldemar Jungner of Sweden in 1899. At that time, the only direct competitor was the lead–acid battery , which was less physically and chemically robust. With minor improvements to the first prototypes, energy density rapidly increased to about half of that of primary batteries, and significantly greater than lead–acid batteries. Jungner experimented with substituting iron for

13108-516: Was launched on 5 March 1992 at the Cyclex exhibition in Olympia, London , when a prototype was demonstrated to both press and public. The price (mail order) was £499, comparable with a top of the range tourer or mountain bike at that time. The initial production target was 10,000 Zikes a month. In May 1993 press reports stated that Tudor Webasto had terminated production because of low sales and that Sinclair

13224-477: Was limited to 15 miles per hour (mph) to avoid classification as a motorcycle under UK law. The Sinclair Zike was developed by Sir Clive Sinclair following the commercial failure of the Sinclair C5 in 1985. Electric vehicles were one of his long-term research ambitions. The Zike was financed largely with his own money, and the manufacture was subcontracted to Tudor Webasto, a Birmingham -based company. The Zike

13340-462: Was seeking a new manufacturer. In the end only around 2,000 units were sold. Sinclair himself moved on to the development of the Sinclair ZETA (Zero Emission Transport Accessory)—a detachable powerpack intended to sit on the wheel of any bicycle to help power it along. Sinclair put the failure of the Zike down to the business structure of the company manufacturing the bicycle. “We brought out

13456-489: Was written by GE scientists at their Battery Business Department in Gainesville, Florida, and later retracted by them, but the damage was done. The battery survives thousands of charges/discharges cycles. Also it is possible to lower the memory effect by discharging the battery completely about once a month. This way apparently the battery does not "remember" the point in its charge cycle. An effect with similar symptoms to

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