Batteries such as in-body radios, tape recorders, cameras, electronic clocks, toys, etc. are commonly classified as dry batteries. The electrolyte in a dry battery is a non-flowable paste, which is called a dry battery (see Figure 1), which is relative to a battery with a flowable electrolyte.

　　The shell is a cylindrical container made of zinc. A carbon rod stands in the center of the zinc cylinder, and a copper cap is fixed on the top of the carbon rod. Carbon rods and zinc cylinders are called dry battery electrodes. The carbon rod that accumulates positive charge is called the positive electrode (symbol +, represents the positive electrode of the battery), and the zinc cylinder that accumulates negative charge is called the negative electrode (the symbol-represents the negative electrode of the battery). Dry batteries do not have recharging characteristics for users and are disposable batteries.

　　The power battery must be a rechargeable battery

　　(1) The biggest difference between dry battery and current power battery is:

　　a) Dry battery electrolyte is a non-flowable paste and does not have recharging characteristics;

　　b) Power battery is an electrolyte in which electrolyte lithium ions can flow, and can be charged thousands of times.

　　(2) The basic similarities between dry batteries and current power batteries:

　　a) There is a positive electrode, a negative electrode, a shell, and an electrochemical reaction;

　　b) Dry batteries and power batteries have basically the same physical characteristics on a single cell, with cylindrical and square shapes.

　　What does power battery pack mean?

　　To the engineers of the main engine manufacturer, the fuel tank is a fuel tank, which is a liquid volume. However, I saw that there are power battery packs one after another on the electric car. Open the battery pack, there are many countless batteries. The power battery began to call a battery a single cell, and a group connected in parallel was called a module, the modules were connected in series, called a battery pack, and the battery packs were connected in series called a battery system. One dry battery can only do 1.5V. People want a 3V power supply and must use 2 dry batteries in series. The capacity of a single cell cannot be very high. People want a power source with a large capacity, and a single battery must be connected in parallel.

　　The vehicle power supply is generally above 300V and 200A. The current basic method is to connect single batteries in parallel to form a module, modular batteries in series to form a battery pack, and battery packs in series to form a power system.