Lithium-ion battery cathode material
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 apple-laptop-battery-c-69_110.html” target=”_blank”>powerbook batterymajor 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 vgp-bps13 , vgp-bps13/s , vgp-bps13a/b vgp-bps13b/bdischarge 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.
And deep charge-discharge lithium-ion batteries can improve the actual capacity? Experts clearly told me that this is meaningless. They even said that the so-called three full charge-discharge prior to use of “activation” in the knowledge of both of them, Dr. Lane, do not understand this as a need. Why do so many people, however, after the deep charge-discharge capacity of Battery Information label will occur where a change? Will be mentioned later.
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 easy battery 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. 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 deep charge-discharge to calibrate the battery chips.