Megawatt-tec

Battery bible

Information about old and new batteries.

Courtesy of Megawatt-tec.

Alkaline battery

Alkaline battery

Most alkaline batteries are primairy batteries and can be used only once. There is a development to make alkaline batteries rechageable.
As in a Zinc carbon battery the ingredients are similar; zinc, manganese-oxide in carbon.
But not in an acid environment like ammonium chloride (pH=5) but in a caustic environment with potassium hydroxide (pH>8 )
Compared with the Zinc carbon battery the alkaline battery has a longer shelf life and a higher energy density.
Energy density is the amount of energy per mass of the battery. Because there are different sizes of a battery like AAA size, the energy density per chemistry type, in this case alkaline battery is the same.
But if you compare with other electro-chemistry type like Zinc-carbon vs Alkaline the energy density is different

Alkaline batteries are not as prone to leak as the Zinc carbon battery but when not used for a long tie they will leak.
The disadvantage of an alkaline battery is its high internal resistance.

Advantages of alkaline batteries

Long battery life with a fantastic shelf life.

There are few types of batteries on the market today that have both the shelf life and the battery life of alkaline batteries -- especially when it comes to the devices they are powering. A long shelf life means that an alkaline battery will hold its charge even if you don't use it for years after its manufacturing. This is a big difference from other types of batteries which are recommended to be opened and used or charged at least once within the first year of purchase. The average alkaline battery can last upwards of seven years, sometimes even more without ever being used, and will only lose five percent of its energy by doing so. And then when you do use them, the alkaline battery will power your devices for months on end even with regular use. Don't believe us on this? Just consider when the last time was that you changed your remote's batteries.

Safe to handle and use.

Many batteries are dangerous and must be handled with extreme care. Take lead and acid-based batteries, which can have severe health repercussions if they are destroyed and those materials are touched. In contrast, alkaline batteries, while it obviously isn't recommended to open them up, their hazardous materials are much harder to reach with a much lower susceptibility to leakage. This makes them much safer to handle and use.

High energy density.

One of the primary competitors of the alkaline battery is the zinc-carbon battery, but alkaline batteries far and away outperform them thanks to their high energy density. In fact, the average alkaline battery will have double the energy density of a similarly sized zinc-carbon battery. This high density enables the alkaline battery to produce the same amount of energy for twice the period of time. Ability to operate across temperatures. Another frustrating thing about other types of batteries is that they often don't work well or will even outright fail in extreme temperatures. Alkaline batteries are not like this. The alkaline battery will operate well both in hot and cold temperatures without users noticing any type of impact in its performance. This is why alkaline batteries are the most recommended type of battery to use in outdoor equipment like flashlights, walkie talkies, mosquito repellant devices, and more.
Leaks Over time, alkaline batteries are prone to leaking potassium hydroxide, a caustic agent that can cause respiratory, eye and skin irritation. This can be avoided by not mixing different battery types in the same device, replacing all of the batteries at the same time, storing in a dry place, and removing batteries from devices for storage.

Battery anatomy

Alkaline cutout
Source:cdn.britannica.com

Structure of an Alkaline Battery To generate electricity, a typical battery requires three components: Anode: High purity zinc powder Cathode:Electrolytical produced manganese dioxide An electrolyte: Concentrated potassium hydroxide Components of Alkaline Battery Steel shell Other important accessories: Negative component- primarily made up of a sealing ring, a copper needle, and a base. Steel can Separator paper Conductive graphite Cathode mix Conductive graphite Cathode mix Collector nail Sealing plug Sealant Negative cap

Development of the alkaline battery (history)


Development of Alkaline Batteries Alkaline batteries were invented in the early twentieth century. Important people associated with the creation, development, and spread of the alkaline battery include: Ernst Waldemar Jungner: In March 1899, he created the first patent for alkaline batteries. He envisioned that they would be used mainly in circumstances that required a large amount of consistent energy. This patent was given in Sweden. Georg Neumann: Neumann was a French scientist who created the first alkaline sealed cell in 1947 in Paris during his work for the Bureau Technique Gautrat. Alred Landau: He created the first iterations of the Rayovac batteries in 1906. Rayovac lithium batteries were first marketed in 1949. Lewis Urry: In 1949, this inventor created the Eveready alkaline battery. Although this battery was not immediately accepted by consumers, after several years he became successful. Thirty years after its invention, the battery and the company that made it changed their names to Energizer.
Capacity Unlike NiMH rechargeable batteries, alkaline batteries are normally not sold with a nominal capacity. Alkalines have a high internal resistance, and a high thermal coefficient of resistivity - the faster an alkaline battery is drained, the higher percentage of the load it dissipates as heat. Therefore, the capacity of an alkaline battery is strongly dependent on the load, even at moderate loads. A AA-sized alkaline battery might have an effective capacity of 3000 mAh at low power, but at a load of 1000 mA, which is common for digital cameras, the capacity could be as little as 700 mAh.[2] Current The amount of current an alkaline battery can deliver is roughly proportional to its physical size. This is a result of decreasing internal resistance as the internal surface area of the cell increases. A general rule of thumb is that an AA alkaline battery can deliver 1000mA without any significant heating. Larger cells, such as C and D cells, can deliver more current. Applications requiring high currents of several amps, such as high powered flashlights and boom-boxes, will require D sized cells to handle the increased load. Volume for volume, alkaline batteries have inferior current handling capacity when compared to other chemistries like NiCd and NiMH. However, alkaline batteries cost significantly less.
5.4 Effect of Temperature The alkaline-manganese dioxide system is best suited for use over a temperature range of -4°F to 130°F (-20°C to 54°C). At lighter loads, some output can be obtained at temperatures as low as -20°F( 30°C). Actual service depends on cell size and current drain. For most cells, up to 75 percent of the rated capacity at room temperature can be delivered at 32°F(0°C). The graph in Figure 8 illustrates how cell size and current drain affect performance over a range of temperatures. As current drain increases, temperature impact becomes more dramatic. Low temperature 5.5 Internal Resistance Alkaline cells, because of their compact construc tion and highly conductive electrolyte, have low internal resistance, usually less than 1 ohm. The low internal resistance characteristic is a benefit in applications - involving high current pulses. Unlike regular zinc-carbon cells, alkaline cells do not require rest periods between pulses and maintain their low internal resistance, increasing only at the very end of useful life.

Electrochemistry



The half-reactions are:

Zn(s) + 2OH−(aq) ⇌ ZnO(s) + H2O(l) + 2e−       [E oxidation° = +1.28 V]
2MnO2(s) + H2O(l) + 2e− ⇌ Mn2O3(s) + 2OH−(aq)     [E reduction° = +0.15 V]

Overall reaction:

Zn(s) + 2MnO2(s) ⇌ ZnO(s) + Mn2O3(s)      [e° = +1.43 V]

Primary batteries like the alkaline battery are very popular. On a yearly base about 10 billion are sold.

Size

The alkaline batteries have different sizes ranging from AAA to AA, C, D, 9 V and others sizes. AAA and AA are suited for low-drain applications like clocks and flash lights. But the same AA size is made, and used for high-drain applications. C, D and 9 V are suited for high-drain applications. Others include micro alkaline button cells, coin cells, AAAA and the like. AA is the most widely used alkaline battery cell size, while the AAA size is the fastest growing. Size C, D and 9 V are used for specific applications which have steady demand. However, other sizes such as micro alkaline coin cells and button cells are used in few industrial and medical applications.

Environment

Alkaline batteries are not to bad for the environment. They can be disposed as trash and do not require active collection and recycling. Currently all alkaline are mercury-free and do not pose any environmental pollution or hazard on disposal. "Disposal Unlike other types of batteries, Alkaline batteries can be disposed of in the regular trash in most locations. [3], [4] The state of California, however, has made it illegal to throw alkaline batteries in the trash. In Europe the battery disposal is controlled by the WEEE regulations, and as such alkaline batteries must not be thrown in with domestic waste. They should be disposed through local recycling stations / waste dumps." This creates a positive demand for these batteries, since other rechargeable consumer batteries needs to be properly collected and recycled. Additionally, the environment-friendly feature makes a consumer feel good while using these batteries as they do not pollute the environment. Moreover, they will likely favor the easy disposal, which is expected to influence them to use alkaline batteries.

Future developments

Secondary Alkaline Batteries Rechargeable alkaline battery is a niche market, which is almost replaced by other rechargeable battery chemistries. Although these batteries are likely to maintain charge for years, they are still at a nascent stage. These batteries are available at the most widely used sizes of AAA, AA, C and D. The usage of these batteries is limited to specific applications. However, one of the major advantages of rechargeable alkaline batteries is that it is likely to find usage in all applications that need primary alkaline batteries. These batteries are manufactured through a small variation in chemical composition of alkaline batteries. This makes these batteries leak-proof even during the recharging process. Some of the key features of rechargeable alkaline batteries include: • These batteries are likely to be rechargeable for nearly 500 charges. However, it needs be recharged at proper intervals. • Compared with the cost involved per charge, alkaline batteries offer low-cost rechargeable batteries, in comparison to the other chemistries. • Rechargeable alkaline batteries also offer a voltage output of 1.5 volts, while other rechargeable chemistries offer an output voltage of 1.2 volts. • These batteries are environment-friendly and therefore are likely to be disposed of easily after complete discharge. However, proper recycling operation is needed for other rechargeable chemistries. • These batteries are ready-to-use and are expected to power the device immediately after purchase.

Recharging of alkaline batteries Recharging of alkaline batteries is uncommon, but possible. When recharging an alkaline cell one must take into account 3 factors: Charging current, termination voltage and cell temperature. An alkaline cell can be safely charged with a constant current source of 100mA or more. The termination voltage should not exceed 1.5 Volts per cell. An ideal charging circuit will supervise cell temperature while charging. Alkaline batteries can typically be charged several dozen times without losing significant capacity.

Conclusion

Conclusion Alkaline batteries remain the most frequently consumed battery chemistry due to wide availability, the range of suitable applications, and reliability in many different environments and climates. This trend is expected to remain steady in the short- and medium-terms due to limited options for equal performance battery chemistries at a similar price point. In the long term, as lithium batteries become more affordable and more widely available, a noticeable shift will occur from alkaline to lithium batteries. The level of alkaline battery production will remain quite consistent as it will likely acquire market share that the heavy-duty segment will be relinquishing. Alkaline batteries will become the new affordable standard as heavy-duty batteries become less capable of powering the needs of an increasing number of consumer gadgets. Prices: AA size battery costs about $1 and has up to 3000 mAh of charge capacity. Energy density: 100 Wh/kg 5.7 Shelf Life Using the MN1300 data from Table 1 the previous equations can be used to determine energy density for this cell. Gravimetric Energy Density: 59.2 130.4 15.00 Ampere-Hours x 1.2 Volts = Watt-Hours or Watt-Hours 0.304 Pounds (0.138 Kilograms) Pound Kilogram Volumetric Energy Density: 5.23 320 15.00 Ampere-Hours x 1.2 Volts = Watt-Hours or Watt-Hours 3.44 Cubic Inches (0.563 Liters) Cubic Inch Liter Alkaline cells have long shelf storage life. After one year of storage at room temperature, cells will pro vide 93 to 96 percent of initial capacity. When stored for four years at 70°F (21°C), service of about 85 percent is still attainable. Storage at high temperatures and high humidity will accelerate degradation of chemical cells. At low temperature storage, the chemical activity is retarded and capacity is not greatly affected. Recommended storage conditions are 50°F (10°C) to 77°F (25°C) with no more than 65 percent relative humidity. ­ Figure 11 compares various DURACELL® zinc anode systems and the effect of temperature on capacity retention. At room temperature, the alkaline system loses approximately 5 percent capacity after one year of stor age. Subsequent capacity loss is approximately 2 percent per year. By comparison, zinc-carbon cells lose nearly 15 percent capacity per year at room temperature. As the temperature elevates, capacity losses increase. At temperatures above 113°F (45°C), the regular zinc-car bon cells will be completely discharged within one year, whereas the alkaline system will still retain approximately 80 percent of its original capacity.