How does the battery charge? The circuit of this device is complex or not, in order to make the device with your own hands? Is the charger for a car battery fundamentally different from that used for mobile phones? We will try to answer all the questions posed later in the article.
General information
The battery plays a very important role in the functioning of devices, assemblies and mechanisms for the operation of which electricity is required. So, in vehicles, it helps to start the engine of the machine. And in mobile phones, batteries allow us to make calls.
Charging the battery, the scheme and principles of operation of this device are considered even in the school physics course. But, alas, many of this knowledge has already been forgotten before the release. Therefore, we hasten to remind you that the principle of occurrence of the voltage (potential) difference between two plates, which are specially immersed in an electrolyte solution, is based on the battery.
The first batteries were copper-zinc. But since that time, they have significantly improved and modernized.
How is the battery
The only visible element of any device is the case. It provides a common and consistent design. It should be noted that the name "battery" can be fully applied to only one cell of the battery (they are also called banks), and there are only six of them in the same standard 12V car battery.
We return to the case. Tough demands are made on him. So, it should be:
- resistant to aggressive chemicals;
- able to tolerate significant temperature fluctuations;
- with good vibration resistance.
All these requirements are met by a modern synthetic material - polypropylene. More detailed differences should be highlighted only when working with specific samples.
Principle of operation
As an example, we consider lead-acid batteries.
When there is a load on the terminal, a chemical reaction begins, which is accompanied by the release of electricity. Over time, the battery will run out. And how is it restored? Is there a simple outline?
Charging the battery is not difficult. It is necessary to carry out the reverse process - electricity is supplied to the terminals, chemical reactions occur again (pure lead is restored), which in the future will allow the use of a battery.
Also during charging, an increase in the density of the electrolyte occurs. Thus, the battery restores its original properties. The better the technology and materials used in the manufacture, the more charge / discharge cycles the battery can withstand.
What are the battery charging circuits?
The classic device is made from a rectifier and a transformer. If we consider all the same car batteries with a voltage of 12 V, then the charges for them have a constant current of about 14 V.
Why so? This voltage is necessary so that current can flow through a discharged car battery. If he himself has 12 V, then a device of the same power cannot help him, therefore they take higher values. But in everything you need to know the measure: if the voltage is too high, this will adversely affect the life of the device.
Therefore, if you want to make a device with your own hands, it is necessary for cars to look for suitable charging schemes for car batteries. The same applies to other techniques. If you need a lithium-ion battery charging circuit , then you need a 4 V device and no more.
Recovery process
Suppose you have a circuit for charging the battery from a generator, by which the device was assembled. The battery connects and the recovery process begins immediately. As it proceeds, the internal resistance of the device will increase. With it, the charging current will drop.
When the voltage approaches the maximum possible value, then this process generally does not proceed. And this indicates that the device was successfully charged and can be turned off.
Technology recommendations
It is necessary to ensure that the battery current is only 10% of its capacity. Moreover, it is not recommended either to exceed this indicator or to reduce it. So, if you go the first way, the electrolyte will start to evaporate, which will significantly affect the maximum capacity and battery life. On the second path, the necessary processes will not occur at the required intensity, because of which the negative processes will continue, although to a slightly lesser extent.
Charging
The described device can be bought or assembled by yourself. For the second option, we need electric circuits for charging batteries. The choice of technology by which it will be made should depend on which batteries are targeted. You will need such components:
- Current limiter (designed on ballast capacitors and transformer). The larger the indicator can be achieved, the greater the current value will be. In general, this should be enough for the charging to work. But the reliability of this device is very low. So, if you break the contacts or mix something up, then both the transformer and the capacitors will fail.
- Protection in case of connecting the "wrong" poles. To do this, you can design a relay. So, the conditional tie is based on the diode. If you mix up the plus and minus, then it will not pass current. And since a relay is tied to it, it will be de-energized. Moreover, you can use this circuit with a device based on both thyristors and transistors. It is necessary to connect it to the wire break, with which the charging itself is connected to the battery.
- The automation that battery charging should have. The circuit in this case should ensure that the device will only work when there really is a need for it. For this, with the help of resistors, the response threshold of the control diode is changed. It is believed that 12 V batteries are completely when their voltage is within 12.8 V. Therefore, this indicator is desirable for this circuit.
Conclusion
So we examined what battery charging is. The circuit of this device can be performed on a single board, but it should be noted that this is rather complicated. Therefore, they are made multi-layered.
In the framework of the article, various circuit diagrams were presented to your attention, which make it clear how, in fact, the charging of batteries occurs. But you need to understand that these are only general images, and more detailed ones with indications of ongoing chemical reactions are special for each type of battery.