The difference between those batteries in series and in parallel

Parallel: Several batteries, positive and negative, negative and negative are connected side by side, the voltage is constant, the capacity increases, and the corresponding current also increases. Tandem: Several battery heads are stringed together with positive and negative, the first section is negatively connected to the second section, and so on. The voltage increases and the capacity does not change. That is to say, if they are connected in series, the electromotive force is the sum of the electromotive forces of the two batteries. If they are connected in parallel, the voltage they provide to the electrical appliances is as large as the electromotive force of only one battery. I hope my answer can help you! I am also learning this part of the knowledge, it is difficult,

When connected in series, the voltage is the sum of the two battery voltages. When connected in parallel, the voltage is equal to the voltage of the two batteries

Increase the voltage in series and increase the capacity in parallel. For example, if you have two 1.5 volt, 2000 mAh batteries, you will get a 3 volt, 2000 mAh battery in series, and a 1.5 volt, 4000 mAh battery in parallel.

1. When the batteries are connected in parallel, the voltages are equal everywhere, that is, Ua=Ub=Uc=Uo; the current is the sum of the currents of the respective batteries, that is, Io=Ia+Ib+Ic. (See Figure 1 for the parallel circuit of the battery)

The battery is connected in parallel for the case where the voltage is constant and the current needs to be increased.

2. When the batteries are connected in series, the currents are equal everywhere, that is, Io=Ia=Ib=Ic; the voltage is the sum of the voltages of the respective batteries, that is, Uo=Ua+Ub+Uc. (See Figure 2 for the series circuit of the battery)

The battery is used in series for applications where the current is constant and the voltage needs to be increased.

Whether in series or in parallel, the output power of the battery pack increases.

1, in series, the current is constant, the voltage is added; in parallel, the voltage is constant, the current is added

2, although the voltage has not changed, the two 12v batteries are connected in series in order to obtain higher voltage to adapt to the electrical appliances. It is necessary to have a current of 10A above 100w, such as an inverter with a design value of 12v input, which is for switches and wires. The requirements are extremely high, so reducing the current is the main reason, it is necessary to connect two parallels, but the normal discharge current is allowed to double, if the current is only 5A when using 24v. Therefore, many places use high-voltage electrical appliances (such as electric vehicles). But some appliances are originally 12v. When their power (current) is large, the electric motor, in order to improve the working time of the battery or the current of a single battery is not enough to drive, the battery is only 12v, and some appliances have relatively large power.

The two 6V batteries are connected in series at 12V. The two 12V batteries are only 12V in parallel. The so-called parallel connection is to connect the positive pole to the positive pole and the negative pole to the negative pole.

The two 12v batteries are connected in series in order to obtain higher voltage to adapt to the electrical appliances. The battery is only 12v, and some of the electrical appliances have relatively large power. The current of 10A is more than 100w, which is extremely demanding for switches and wires. If the current is only 5A when using 24v, the current is the main reason, so many places use high-voltage electrical appliances (such as electric vehicles). This is also the case. However, some appliances are originally 12v, for example, the design value is 12v input. Inverters, motors... When their power (current) is large, in order to increase the working time of the battery or the current of a single battery is not enough to drive, two parallel connections are required, although the voltage does not change, but the normal discharge is allowed. The current has doubled.

The difference between battery parallel and series is mainly the difference in voltage and capacity. Take the voltage of 3.7V, the capacity is 3000mAh lithium battery, the same is two batteries, if it is two strings, then the battery model is: 7.4V /3000mAh, if it is two, the model will become: 3.7V/6000mAh. When connected in series, the voltage will increase and the capacity will not change. When connected in parallel, the capacity will increase and the voltage will not change. But the batteries we often use are all connected in series and parallel, such as: three strings and four. I hope I can help you.

The battery parallel voltage does not change, which can increase the supply current.

The battery can be connected in series to increase the supply voltage and the current is constant.

In the battery pack, batteries are connected in series to obtain a required operating voltage. If you need higher capacity and more current, you should connect the batteries in parallel. There are also some battery packs that combine the two methods of series and parallel. The battery of a laptop computer may be connected in series with four 3.6V lithium-ion batteries, the total voltage reaches 14.4V; then, the two batteries connected in series are connected in parallel, so that the total power of the battery pack can be Increased from 2000 mAh to 4000 mAh. This connection is called "four-string two-in-one", which means that two sets of battery packs connected in series by four batteries are connected in parallel.

A battery is generally used in watches, backup memories, and cellular phones. The nominal voltage of a nickel-based battery is 1.2V, the alkaline battery is 1.5V, the silver oxide battery is 1.6V, the lead acid battery is 2V, the lithium battery is 3V, and the lithium-ion battery has a nominal voltage of 3.6. V. Using lithium ion polymers and other types of lithium batteries, its rated voltage is generally 3.7V. If you want to get an unusual voltage like 11.1V, you have to connect three batteries in series. With the development of modern microelectronics technology, we have been able to power a cellular phone and low-power portable communication products with a 3.6V lithium-ion battery. In the 1960s, mercury batteries, which were widely used in illuminance meters, have now completely withdrawn from the market due to environmental concerns.

Nickel-based batteries have a nominal voltage of 1.2V or 1.25V. There is no difference between them except for market preferences. Most commercial batteries have a voltage of 1.2V per cell. For industrial,special and military batteries , the voltage of each cell is still 1.25V.

In parallel

In order to get more power, you can connect two or more batteries in parallel. In addition to paralleling the batteries, another option is to use a larger battery. This approach does not apply to all situations due to the limitations of the battery that can be used. In addition, large-sized batteries are not suitable for the form factor required for a dedicated battery. Most chemical batteries can be used in parallel, while lithium-ion batteries are best suited for parallel use. The battery pack consisting of four cells in parallel maintains a voltage of 1.2V while the current and run time are increased by a factor of four.

Examples of battery packs have a lower impact on high-impedance or "open-circuit" batteries in battery parallel circuits compared to battery series, but parallel battery packs reduce load capacity and reduce run time. This is like an engine that only starts three cylinders. The damage caused by the short circuit of the circuit is greater because, in the event of a short circuit, the faulty battery will quickly deplete the power of other batteries and cause a fire.

Tandem

Portable devices that require high power are typically powered by a battery pack in which two or more cells are connected in series. If a high voltage battery is used, the size of the conductors and switches can be made small. Mid-priced industrial power tools typically use batteries powered from 12V to 19.2V, while advanced power tools use batteries from 24V to 36V for greater power. The automotive industry eventually increased the ignition cell voltage of the starter from 12V (actually 14V) to 36V, or even 42V. These battery packs consist of 18 series lead acid batteries. In the early hybrid cars, the battery pack used for power supply had a voltage of 148 V. The battery pack used in the newer models had voltages of up to 450 V to 500 V, mostly nickel-based chemical batteries. A nickel-metal hydride battery pack with a voltage of 480V is made up of 400 nickel-metal hydride batteries in series. Some hybrid cars have also been tested with lead acid batteries.

The 42V car battery is expensive, and it produces more arc on the switch than the 12V battery . Another problem with using a high-voltage battery pack is that it is possible to experience a failure of a certain battery in the battery pack. It's like a chain, the more batteries are connected in series, the higher the chance of this happening. As long as there is a problem with one of the batteries, its voltage will decrease. At the end of the day, a “disconnected” battery may interrupt the delivery of current. It is not easy to replace the "bad" battery, because the old and new batteries do not match each other. In general, the capacity of new batteries is much higher than that of older batteries.

Let's look at an example of a battery pack. The third battery produces only 0.6V instead of the normal 1.2V (Figure 1). As the operating voltage drops, it reaches the critical point of discharge end faster than the normal battery pack, and its use time is also drastically shortened. Once the device is powered off due to low voltage, the remaining three good batteries will not be able to send the stored power. At this time, the third battery also exhibits a large internal resistance. If the load is also present at this time, the output voltage of the entire battery chain will be greatly reduced. In a set of serial batteries, a poorly performing battery, like a plug that blocks a water pipe, creates a huge amount of resistance that prevents current from flowing. The third cell will also be shorted, which will reduce the terminal voltage to 3.6V, or disconnect the battery pack link and cut off the current. The performance of a battery pack depends on the performance of the worst battery in the battery pack.