Lithium-ion battery development prospects

Lithium-ion battery development prospects


Lithium-ion Acer TravelMate 4500 Battery for its unique performance advantages in portable appliances such as laptop computers, cameras, mobile communications are universally applied. At present the development of large-capacity lithium-ion batteries in electric vehicle to start a trial, expected to become the 21st century, the power of electric vehicles, one of the main driving force, and a satellite, aerospace and energy storage aspects applied. With the energy shortage and global environmental pressures. Lithium is now widely used in electric vehicle industry, especially iron phosphate lithium battery materials, the appearance, they also promote the development of the lithium battery industry and application.

The basic performance of the battery

(1) the battery open circuit voltage

(2) The battery internal resistance

(3) The battery voltage

(4) The charging voltage

Charging voltage is the secondary Acer Aspire 1410 Battery charging, the external power added to the battery voltage at both ends. The basic method of charging Youheng current charging and constant voltage charging. Generally use the constant current charging, the characteristics of the process of charging the charge current constant. As the charging progresses, the active substance was restored, the electrode reaction area is shrinking, the electrical polarization gradually increased.

(5) Battery Capacity

Battery capacity refers to the amount of electricity from the battery to obtain, often C, said the unit, said common Ah or mAh. The electrical properties of the battery capacity is an important indicator. The battery capacity is usually divided into theoretical capacity, practical capacity and rated capacity.

The capacity of the battery capacity of the decision by the electrodes, if the electrode capacity Acer Laptop Battery varies depending on the capacity of the battery capacity that smaller electrodes, but by no means the sum of positive and negative capacities.

(6), the storage battery performance and life of

One of the main characteristics of chemical power sources is used to release electrical energy can be stored when not in power. The so-called secondary battery for storage performance is to maintain the ability to recharge your batteries.

For the secondary battery, battery performance measure of good or bad, when life is an important parameter. Following a secondary battery charge and discharge, is called a cycle (or have been in this cycle). At a certain charge and discharge system, the battery capacity reaches a certain specified value before the battery can withstand the charge and discharge times known as the secondary battery life cycle. Lithium-ion batteries have excellent storage performance and long cycle life.

The characteristics of lithium-ion Laptop Battery

A. High-energy density

Lithium-ion batteries are the same weight capacity nickel-cadmium or nickel-hydrogen batteries for half of the volume is 40-50% nickel cadmium, nickel hydrogen 20-30%.

B. High-Voltage

A lithium-ion battery voltage of the monomer 3.6V (average), equivalent to three series of nickel-cadmium or nickel metal hydride batteries.

C. pollution

Lithium-ion batteries do not contain, such as cadmium, lead, mercury, like the harmful metals.

D. non-lithium

Lithium-ion batteries contain lithium metal, which is not on the Prohibition of the transport plane carrying lithium batteries on aircraft restrictions.

E. High cycle life

Under normal conditions, the lithium-ion battery charge and discharge cycles of more than 500 times.

F. No memory effect

Memory effect refers to the nickel-cadmium battery charge-discharge cycle, the Acer Aspire 1680 Battery capacity decrease. Lithium-ion batteries do not exist this effect.

G. Fast Charge

Rated voltage of 4.2V using a constant-current constant-voltage charger can make lithium-ion batteries in one to two hours to be fully charged.

Lithium battery protection circuit

By the two FET and special protection Manifold S - 8232 composition, over and over-charge control tubes FET2 discharge control tube FET1 series in the circuit to protect IC from the battery voltage is monitored and controlled, when the battery voltage up to 4.2V When, over-charging protection tube FET1 deadline, stop charging. To prevent malfunction, generally outside the circuit plus a delay capacitor. When the battery in a discharged state, the battery voltage down to 2.55V, the excessive discharge control tube FET1 deadline to stop power to the load. Over-current protection is greater when the load current flows out of date, control FET1 to close to stop the load discharge, the purpose is to protect the battery and FET. Over-current detection is the use of FET on-resistance as a sense resistor to monitor its voltage drop, when the voltage drop exceeds a set value, to stop discharging. In the circuit there is also generally added delay circuit to distinguish between inrush current and short-circuit current. The circuit is fully Acer TravelMate 2300 Battery functional, reliable performance, but are highly specialized and dedicated Manifold difficult to buy, easy amateur imitation.

Because Li + battery overcharge or over-discharge may cause an explosion and cause personal injury, so the use of such batteries, security is a major concern. Therefore, the commercial lithium-ion batteries typically include a protection circuit such as the DS2720 (Figure 7). DS2720 provides a rechargeable Li + batteries all the necessary protection features, such as: to protect the battery during charging to prevent the circuit overcurrent, by limiting the discharge voltage of the battery to extend battery life. The circuit diagram above. .

Simple charging circuit

At present, many businesses to sell without charging a single-board lithium battery. Its superior performance, low cost, can be used for home-made products and the maintenance of substitution lithium battery pack, so well received by the electronic enthusiasts love. Interested readers can refer to Figure 2 produce a charge sheet. The principle is: use a constant voltage to the battery, ensuring that no overcharge. Input DC voltage is higher than the 3-volt rechargeable Acer TravelMate 4000 Battery can be. R1, Q1, W1, TL431 adjustable precision regulator circuits formed, Q2, W2, R2 constitute the adjustable constant current circuit, Q3, R3, R4, R5, LED charging indicator for the circuit. With the rechargeable battery voltage was increased, the charge current will gradually decrease until the battery is full after the voltage drop on R4 will be reduced, so that Q3 ended, LED will be extinguished, in order to ensure the battery can be sufficient, please continue after lights out Charge 1-2 hours. When used please Q2, Q3 fitted with a suitable heat sink. Advantage of this circuit are: production of simple, easy to purchase components, charging safety, display and intuitive, and will not damage the battery. By changing the W1 series can be multiple-rechargeable lithium battery and change the W2 can be carried out large-scale charge current regulation. The disadvantage is that: no over-discharge control circuit.

Application of single-cell lithium battery for example

1, substitution of products for battery maintenance, many batteries: such as notebook computers that used by the maintenance found that damage to the battery pack when the battery is only an isolated problem. Can be the appropriate choice of a single lithium battery replacement.

2, producing bright mini flashlight I had used a single 3.6V1.6AH lithium Acer TravelMate 290 Battery with an ultra-bright white LED made of a micro-torch, easy to use, compact appearance. And because the battery capacity, the average nightly use of half an hour, has been more than two months remain before needing to recharge.

3, instead of 3V power supply

As a single lithium battery voltage of 3.6V. Therefore, only a lithium battery can be replaced by two regular batteries, to the radio, Walkman, cameras and other small household electrical appliances power supply, not only light weight, but also a long time of continuous use.

Lithium battery saved

After the lithium batteries need to save enough electricity. In more than six months can be stored at 20 ℃, showing that lithium batteries suitable for preservation at low temperatures. It has been suggested that rechargeable battery placed in the refrigerator interior preservation, is indeed a good idea.

There is the phenomenon of self-discharge of lithium batteries for a long time to save battery depletion will lead to the destruction of the internal structure of the battery, reducing battery life. Therefore, long-term preservation of the lithium Acer BATCL50L Battery should be every 3 to 6 months make up power once, that is charged to voltage of 3.8 ~ 3.9V (Li-ion battery voltage of 3.85V the best save so) is appropriate.