Note lithium battery of series and parallel
The power lithium battery in series and in parallel use, which sounds like a very simple, but to follow a few simple rules, you can avoid unnecessary problems. Lithium battery pack contains two parts: the lithium battery and lithium battery protection circuit.
In the lithium group is more than a lithium battery in series, to get the required operating voltage. If you need a higher capacity and higher current, it should put lithium batteries in parallel. There are also a number of battery packs in series and in parallel with the combination of these two methods. A laptop battery may be the four 3.6V lithium-ion batteries in series, the total voltage reaches 14.4V; then, then strung together two batteries in parallel, so that the total power consumption of the battery pack can be from 2000 up to 4000 mA when mA. This connection is called "two-and four-string," which means: put in parallel two by four batteries in series with the battery pack. Lithium-ion battery nominal voltage is 3.6V. Lithium ion polymer batteries, and other types of lithium, its rated voltage is typically 3.7V. If you want to get like this are not common 11.1V voltage, you have to put three such batteries connected in series. Series portable devices that require high power, usually by two or more batteries in series battery pack. Another problem with the use of high-voltage battery pack brings is likely to encounter situations where a section of the battery pack battery failure. It's like a chain, the more series with the battery, there is higher probability of this situation. As long as a battery problem, its voltage is reduced. In the end, an "off" the battery may interrupt current delivery. And to replace the "bad" batteries is no easy task, because the new and old batteries are not mutually matched. In general, the capacity of a new battery is much higher than the old cell. With the decline of the operating voltage, it reaches the discharge end of the critical point faster than a normal battery pack, while its time dramatically shortened. Once the device is cut off due to the power supply voltage is too low, the rest of the cells remained intact as the battery is not able to send out the stored charge. At this time, the bad battery cell that also presents a great resistance, but also with the load at this time, if, then, will cause the entire chain of the battery output voltage will fall significantly. In one set of batteries in series, one section of the poor performance of the battery, like a blocked pipe plug, will have a huge resistance to prevent current flow in the past. Other batteries will short-circuit, which will reduce the terminal voltage to 3.6V, or disconnect the battery pack and cut off the current link. Performance of a battery depends on the battery group is the worst performance of the battery piece. In parallel in order to get more power, you can put two or more cells connected in parallel. In addition to the battery in parallel, another approach is to use larger size battery. Due to limited battery can be chosen, this approach does not apply to all situations. In addition, the large size of the battery is not suitable to make special batteries required form factor. Most of the chemical batteries can be used in parallel, while the lithium-ion battery most suitable parallel. Connected in parallel by four
battery cells, the voltage is held 3.6V, and the current and the operating time is increased to four times. Compared with the cells in series, the parallel circuit in the battery, a high impedance or "open" Impact of the battery is small, however, will reduce the load in parallel to the battery capacity and shortening the operation time. This is like a three-cylinder engine is only started. Damage caused by a short circuit will be even greater, because, in the short circuit, faulty battery will quickly run out of other batteries in the battery and cause a fire. When using such a series-parallel connection method, the design is very flexible, you can use a standard battery size to the rated voltage and current needs. It should be noted: the total power of the battery will not be because of the different connection method is changed. Power is equal to the voltage multiplied by current. For lithium-ion batteries, the series-parallel connection method is very common. The most common kind of battery pack is a 18650 (diameter 18mm, length 650mm), which is protected with the protection circuit board lithium battery, lithium battery protection board can monitor each cell connected together in series, so that its maximum The actual voltage is 14.4V. The lithium battery protection circuit (ie, lithium protection board) can also be used to monitor series with each section of the battery. When the number of cells in series, you must comply with the following basic requirements: to keep clean the battery connection point. When to use four batteries in series, a total of eight connection points (the battery to the connection point of the battery compartment, the battery compartment to the connection point of the next section of the battery). Each connection point is there is a certain resistance, if you increase the connection point, which may affect the performance of the entire battery pack. Do not mix battery, select the consistent performance of the battery. When the battery is low, replace all the batteries. When used in tandem, to use the same type of battery. Pay attention to the battery polarity. If there is a polarity of the battery installed backwards, it will reduce the whole string of battery voltage, rather than increasing voltage. General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.