Laptop battery works
At present, the market almost all notebook computers use lithium-ion battery (Li-ion). Nickel-chromium batteries (Ni-cd), nickel-metal hydride batteries (Ni-MH) that the memory effect has been eliminated; fuel cell is still experimental. Therefore, we discuss mainly the use of lithium-ion batteries.
Lithium-ion battery cathode material of lithium active compounds are usually composed of negative electrode is a special molecular structure of carbon. Common cathode material for the major components of LiCoO2, charging, added to the battery positive pole of the electric potential to force the release of compounds, lithium ion, embedded negative elements arranged in lamellar structure of the carbon. Discharge, lithium-ion from the lamellar structure of carbon precipitation and re-cathode combination of compounds. Lithium-ion movement generated a current. Although the chemical reaction principle is very simple, but in the actual industrial production, the practical problems need to be considered much more: the cathode material additives required to maintain the multiple charge-discharge activity, the negative electrode material, which needs to design the molecular structure of class to accommodate more lithium-ion; fill in the electrolyte between the positive and negative electrodes, in addition to maintaining stability, but also need to have good electrical conductivity, reducing the battery internal resistance. Although the lithium-ion batteries little nickel-cadmium battery memory effect, memory effect of the principle is that crystallization, in the lithium batteries will have little reaction. However, lithium-ion battery capacity after repeated charge-discharge will continue to decline, its causes are complex and diverse. Is mainly positive and negative changes in the material itself, from the molecular level, the positive and negative electrodes of lithium ion on the hole to accommodate the structure will gradually collapse, plug; from the chemical point of view, is the active anode material is passive, there's the other side to form a stable compounds. Physics will appear on the cathode material gradually falling off, etc., in short, can ultimately reduce the battery charging and discharging process of the free movement of the number of lithium-ion. Over-charging and over-discharge, lithium-ion batteries will be positive and negative result in permanent damage, from the molecular level, intuitive understanding, excessive discharge of carbon anode will lead to excessive release of lithium-ion and makes it appear lamellar structure collapsed, over - Rechargeable lithium-ion will too hard go into the negative carbon structure, causing some of the lithium-ion can no longer be released. This is why lithium-ion batteries are usually equipped with charge-discharge control circuit causes. Not suitable for the temperature, will lead to lithium-ion battery inside the reaction of other chemical compounds that we do not want to see, so many of the lithium-ion batteries are being set up between the protective negative temperature-controlled diaphragm or electrolyte additives. In the battery temperature to a certain case, the composite membrane electrolyte membrane hole closed or degeneration, increased battery internal resistance until the circuit, the battery is no longer to heat up, to ensure that the battery charging temperature is normal. Notebook computer lithium-ion batteries are generally with the management of chip and charge control chips. Which management chip in a series of registers, there is capacity, temperature, ID, charge status, discharge frequency values. These values are in use will gradually change. I personally believe that the instructions for use in notebook computers in the "Use a month should put a full-charge" approach to a major role now is to fix these registers where the wrong values, making the battery charge control and the nominal capacity of the battery match the actual situation. Charge control the main control chip, the battery charging process. Lithium-ion battery charging process is divided into two phases, constant-current fast charge phase (when the battery indicator light yellow) and constant-voltage current decreasing phase (the battery indicator light flashes green. Constant-current fast charge phase, the battery voltage is gradually increased The standard voltage to the battery, and then transferred to constant pressure in the control phase of the next chip, the voltage will not rise in order to ensure that no over-charge, current battery, along with the rising gradually weakened to 0, and the ultimate completion of charging. Statistics chip power consumption by recording the discharge curve (voltage, current, time) can calculate the sample battery power, this is what we read in the Battery Information inside wh. value. while the lithium-ion batteries in repeated use, the discharge curve will change, If the chip has not been opportunity to once again read out a complete discharge curve, which is calculated out of electricity that is not accurate. so we need to calibrate the deep charge-discharge the battery chips.
Battery appearance and identification defined
The battery manufacturer, model, as long as regular batteries manufacturers, these two labels certainly have the.
Types of batteries (based on the internal battery of the type of points)
Common for Li-ion lithium-ion battery, Ni-MH Ni-MH battery, Li-polymer lithium-polymer battery, in addition to small to see Ni-Cd (nickel-cadmium batteries) and the latest fuel cell.
Rated Voltage (Nominal Voltage) (Figure)
Li-ion battery: Many people think that said lithium battery means that we are now commonly used in lithium-polymer battery, in fact, lithium batteries, including lithium metal-ion battery (Li-MO2) and lithium-polymer battery (Li-ion) are two. Because Li-MO2 cells to enter the market in 1989, caught fire when the explosion occurred while the die, so it will soon disappear from people's sight, replaced by a safer lithium-polymer battery. It is light weight, in the same capacity under its nickel-metal hydride battery weighs only about 1 / 2, so it is fast becoming the new darling of mobile portable devices have been used in most notebook computers, is now the backbone of notebook batteries.
Fuel Cell (Fuel Cell): Fuel cells are the future of laptop batteries star, it has many types, including proton exchange membrane fuel cell (PEM), alkaline fuel cell (AFC) and solid oxide fuel cell (SOFC) and many other However, due to the fuel cell start-up time and operating temperature and other reasons in fact suitable for notebook computer use only the fuel cell proton exchange membrane fuel cell (PEM). PEM fuel cells using methanol fuel, from the positive and negative electrodes composed of the principle of its power generation is the result of the methanol, after re-enter the negative hydrogen and oxygen enter the cathode, through the catalyst, hydrogen atoms into protons and electrons, by different paths into the cathode, e-cycle to produce electricity through an internal, proton through the electrolyte to achieve positive, combined with oxygen to produce water and electrical and heat. The experts agreed that restricting the commercial application of fuel cells, the biggest factor is the fuel cell to use the metal platinum (Pt) or platinum as catalyst to make the cost of production has been high, the current production cost of the fuel cell 500 ~ 1000 USD / kW. Research shows that only when the fuel cell production costs fell to 50 U.S. dollars / kilowatt level can be truly accepted by consumers. The high cost of fuel cells is mainly due to mass production has not been formed, once entered mass production stage, the price of fuel cells will certainly be greatly reduced. October 2003 NEC launched its latest notebook with the development of fuel cells, allegedly, when the concentration of fuel use 10% of the 300 cubic centimeters of methanol, the laptop computer can use 5 hours. NEC proposed in 2005, will launch a notebook computer allows continuous use 40 hours of fuel cell products. For now, the fuel cell size, performance and cost is not much advantage, but the fuel cell as a back-up power supply or a laptop a good choice. Think about when the notebook can be used continuously 40 hours, it is a kind of what it feels like. Little pollution, and fuel cells can be used repeatedly.
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