In the past few days, when I was sorting out toy airplanes and cars with my son, I was suddenly asked why some batteries are 15V, some charge is 3What about 7V?
I was really stunned and didn't know how to answer.
So I hurriedly worked overtime to systematically understand the battery and give you a science popularization.
There are so many batteries on the market, why are the voltages different?
The voltage of a lead-acid battery is not 12V
Lead-acid battery (VRLA) is a battery in which the electrode is mainly made of lead and its oxide, and the electrolyte is a sulfuric acid solution. In the discharged state of lead-acid battery, the main component of the positive electrode is lead dioxide, and the main component of the negative electrode is lead; In the charging state, the main components of the positive and negative electrodes are lead sulfate.
The nominal voltage of a single-cell lead-acid battery is 20V, can discharge to 15V, I can charge it to 24v；In the application, 6 single-cell lead-acid batteries are often connected in series to form a lead-acid battery with a nominal 12V, as well as 24V, 36V, 48V, etc.
The 9V battery used in our multimeter is not really 9V, and this kind of battery is collectively called a multilayer battery.
Multilayer batteries are used to power meters and measuring instruments. The battery has a small capacity, high voltage, and slow internal chemical reaction, and the discharge current is small, and it can be used for a long time.
Insert teardown**.
Moreover, there is this 12V cylindrical battery, which looks the same as an alkaline battery, but in fact it is not 12V, he is 8 1s5V alkaline batteries are strung together.
In fact, so far, in the materials found by mankind, the potential of lithium batteries is very high, and no matter how high it is, it is unstable, so at present, the highest voltage of a single battery, or galvanic battery, is 3V of lithium battery, and this voltage here is called electrode potential.
The electrode potential refers to the ability of a substance to gain and lose electrons, and because a metal substance is a single substance, it can be divided into strength and weakness according to the arrangement of the periodic table.
However, when we use complex materials such as metal oxides as electrodes, it is not so easy to distinguish their ability to gain and lose electrons, so many scientists have done experiments and developed a ** to record the electrode potential of different materials, which can be as follows