Indicadores sobre batteries Você Deve Saber
Indicadores sobre batteries Você Deve Saber
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The electrochemical reaction in a battery is carried out by moving electrons from one material to another (called electrodes) using an electric current. The first battery was invented in 1800 by Italian physicist Alessandro Volta.
That represents the versatility of energy storage systems—better known as batteries—that scientists are developing today.
While lithium-ion and sodium-ion batteries are commonly used in consumer electronics and are commercialized for use in electric vehicles, scientists are exploring an array of other chemistries that may prove to be more effective, last longer, and are cheaper than those in use today.
Battery performance is thus limited by the diffusion rates of internal chemicals as well as by capacity.
6 volts per cell cylindrical and button batteries; used in digital cameras, small appliances high energy density; supports high discharge rates; long shelf life; expensive lithium-manganese dioxide lithium anode-manganese dioxide cathode with organic electrolyte; 2.8–3.2 volts per cell cylindrical and button batteries; used in digital cameras, small appliances high energy density; supports high discharge rates; long shelf life; expensive Secondary (rechargeable) batteries type chemistry sizes and common applications features lead-acid lead anode-lead dioxide cathode with sulfuric acid electrolyte wide range of sizes; used in automobiles, wheelchairs, children's electric vehicles, emergency power supplies cheapest and heaviest battery; long life; no memory effect; wide range of discharge rates Alkaline nickel-cadmium cadmium anode-nickel dioxide cathode with potassium hydroxide electrolyte common cylindrical jackets; used in power tools, cordless telephones, biomedical equipment excellent performance under heavy discharge; nearly constant voltage; best rechargeable cycle life; memory effect in some; cadmium highly toxic and carcinogenic if improperly recycled nickel-metal hydride lanthanide or nickel alloy anode-nickel dioxide cathode with potassium hydroxide electrolyte some cylindrical jackets; used in smoke alarms, power tools, cellular telephones high energy density; good performance under heavy discharge; nearly constant 1.2-volt discharge; no memory effect; environmentally safe Lithium lithium-ion carbon anode-lithium cobalt dioxide cathode with organic electrolyte most cylindrical jackets; used in cellular telephones, portable computers higher energy density and shorter life than nickel-cadmium; expensive; pelo memory effect
In the 2000s, developments include batteries with embedded electronics such as USBCELL, which allows charging an AA battery through a USB connector, nanoball batteries that allow for a discharge rate about 100x greater than current batteries, and smart battery packs with state-of-charge monitors and battery protection circuits that prevent damage on over-discharge. Low self-discharge (LSD) allows secondary cells to be charged prior to shipping.
Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used for flashlights and a multitude of portable electronic devices.
Batteries come in many shapes and sizes, from miniature cells used to power hearing aids and wristwatches to, at the largest extreme, huge battery banks the size of rooms that provide standby or emergency power for telephone exchanges and computer data centers.
There are a large number of elements and compounds акумулатори цена from which to select potentially useful combinations for batteries. The commercial systems in common use represent the survivors of numerous tests where continued use depends on adequate voltage, high current-carrying capacity, low-cost materials, and tolerance for user neglect.
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The Electrolyte Genome at JCESR has produced a computational database with more than 26,000 molecules that can be used to calculate key electrolyte properties for new, advanced batteries.
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.
With regards to anodes, a number of chemistry changes have the potential to improve energy density (watt-hour per kilogram, or Wh/kg). For example, silicon can be used to replace all or some of the graphite in the anode in order to make it lighter and thus increase the energy density.
When a battery is recharged at an excessive rate, an explosive gas mixture of hydrogen and oxygen may be produced faster than it can escape from within the battery (e.g. through a built-in vent), leading to pressure build-up and eventual bursting of the battery case. In extreme cases, battery chemicals may spray violently from the casing and cause injury. An expert summary of the problem indicates that this type uses "liquid electrolytes to transport lithium ions between the anode and the cathode. If a battery cell is charged too quickly, it can cause a short circuit, leading to explosions and fires".