batteries Opções

batteries Opções

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For instance, energy can be stored in Zn or Li, which are high-energy metals because they are not stabilized by d-electron bonding, unlike transition metals. Batteries are designed so that the energetically favorable redox reaction can occur only when electrons move through the external part of the circuit.

Nickel-cadmium battery is also a type of rechargeable battery that uses nickel oxide hydroxide and the metal cadmium as electrodes. One of the main advantages of Ni-Cd batteries is that they can maintain voltage and hold a charge when not in use.

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.

If the temperature is raised deliberately, faster discharge can be sustained, but this is not generally advisable, because the battery chemicals may evaporate or react spontaneously with one another, leading to early failure.

Charged batteries (rechargeable or disposable) lose charge by internal self-discharge over time although not discharged, due to the presence of generally irreversible side reactions that consume charge carriers without producing current. The rate of self-discharge depends upon battery chemistry and construction, typically from months to years for significant loss. When batteries are recharged, additional side reactions reduce capacity for subsequent discharges. After enough recharges, in essence all capacity is lost and the battery stops producing power.

A battery's capacity is the amount of electric charge it can deliver at a voltage that does not drop below the specified terminal voltage. The more electrode material contained in the cell the greater its capacity. A small cell has less capacity than a larger cell with the same chemistry, although they develop the same open-circuit voltage.[49] Capacity is usually stated in ampere-hours (A·h) (mAh for small batteries). The rated capacity of a battery is usually expressed as the product of 20 hours multiplied by the current that a new battery can consistently supply for 20 hours at 20 °C (68 °F), while remaining above a specified terminal voltage per cell.

The positive and negative terminals of a battery are made of metal, usually lead or copper. The terminals are connected to the battery’s electrodes, which are made of materials that can conduct electricity.

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.

Overcharging (attempting to charge a battery beyond its electrical capacity) can also lead to a battery explosion, in addition to leakage or irreversible damage. It may also cause damage to the charger or device in which the overcharged battery is later used.

Secondary batteries, also known as secondary cells, or rechargeable batteries, must be charged before first use; they are usually assembled with active materials in the discharged state. Rechargeable batteries are (re)charged by applying electric current, which reverses the chemical reactions that occur during discharge/use. Devices to supply the appropriate current are called chargers. The oldest form of rechargeable battery is the lead–acid battery, which are widely used in automotive and boating applications.

PNNL’s Battery Reliability Test Laboratory is part of its world-class battery development capability. The laboratory was established to accelerate the development of grid energy storage technologies that will help modernize the power grid.

An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections[1] for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode.[2] The terminal marked negative is the source of electrons that will flow through an акумулатори бургас external electric circuit to the positive terminal.

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.

Batteries supply DC current which can only flow one way – negative to positive. A battery is made up of three main components: