What kind of battery does the electric car use?

Electric car partners are basically aware of this, and it is obvious that their prospects in the electric car industry are bright. At present, many friends are basically buying electric car models! Even many middle-aged and elderly people are buying electric cars, which shows how good the prospects of electric cars are. So friends all know what batteries are used in electric cars! Today, let's briefly introduce our friends.

What batteries are used for electric vehicles? Electric car battery.

There are two kinds of batteries for automobiles, storage batteries and fuel cells. Batteries meet the objective requirements of pure electric vehicles, including lead-acid batteries, nickel-hydrogen batteries, sodium-sulfur batteries, secondary lithium batteries and air batteries.

Fuel is the special fuel for fuel cell electric vehicles, including alkaline fuel cell (AFC), phosphoric acid fuel cell (PAFC), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC), proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC).

What kind of battery is used for electric vehicles: function

Different types of electric vehicles are slightly different. In a pure electric vehicle equipped with only batteries, batteries are the only power source of the vehicle drive system. In a hybrid vehicle equipped with a traditional engine (or fuel cell) and battery, the battery can not only play the role of the key power source of the vehicle drive system, but also play the role of an auxiliary power source. It can be seen that when starting at low speed, the battery plays the role of the key power source of the automobile drive system; It acts as a power supply when full load accelerates. It can store energy during normal driving, deceleration and braking.

What batteries are used for electric vehicles: composition

The fuel cell is oxidized by fuel at the anode and reduced by oxidant at the cathode. If gas fuel (hydrogen) is continuously supplied to the anode (i.e., cathode of external circuit, also called fuel electrode) and oxygen (or air) is continuously supplied to the cathode (i.e., anode of external circuit, also called /[k0/] gas electrode), the electrochemical reaction can continuously occur on the electrode, and current can be generated. It can be seen that the fuel cell is different from the traditional battery in that its fuel and oxidant are not stored in the battery, but in the storage tank outside the battery. When it works (output current to do work), it needs to constantly replenish fuel and oxidant to the battery and discharge reaction products at the same time. Therefore, it is similar to the traditional gasoline or diesel generator in working mode. Because fuel and oxidant need to be constantly added to the fuel cell when it is working, both fuel and oxidant used in the fuel cell are fluids (gas or liquid). The most commonly used fuels are pure hydrogen, various hydrogen-rich gases (such as reformed gas) and some liquids (such as methanol aqueous solution), and the commonly used oxidants are pure oxygen, purified air gas and some liquids (such as hydrogen peroxide and nitric acid aqueous solution). ).).

The function of fuel cell anode is to provide the interface between fuel and electrolyte and catalyze the oxidation of fuel. At the same time, the electrons generated in the reaction are transmitted to the external circuit or first to the collector plate and then to the external circuit. The function of cathode (oxygen electrode) is to provide the interface between oxygen and electrolyte, catalyze the reduction of oxygen and transfer electrons from external circuit to the reaction site of oxygen electrode. Because most of the reactions on the electrode are multiphase interfacial reactions, in order to improve the reaction rate, most of the electrodes are made of porous materials and coated with electrocatalysts.

The function of electrolyte is to transport ions generated by electrode reaction between fuel electrode and oxygen electrode, and to prevent the direct transfer of electrons between electrodes. The function of diaphragm is to conduct ions, prevent electrons from transferring directly between electrodes, and isolate oxidant and reductant. Therefore, the diaphragm must be an insulating material with electrolyte corrosion resistance and good moisture resistance.

battery

The automobile battery pack consists of a plurality of batteries stacked in series. A typical battery pack has about 96 batteries. For a lithium-ion battery charged to 4.2V, such a battery pack will generate a total voltage of over 400VV. Although the automobile power supply system regards the battery pack as a single high-voltage battery and basically charges and discharges the whole battery pack at a time, the battery regulation system must consider the situation of each battery independently. If the capacity of one battery in the battery pack is slightly lower than that of other batteries, its charging state will gradually deviate from other batteries after several charging and discharging cycles. If the charging state of this battery is not regularly balanced with other batteries, it will eventually enter a deep discharge state, which will affect the damage and eventually lead to battery failure through development and change. In order to avoid this situation, it is basically necessary to monitor the voltage of each battery to determine the state of charge. In addition, there must be a device to charge or discharge the batteries separately to balance the charging state of these batteries.

A key consideration of battery monitoring system is communication interface. As far as intra-PC communication is concerned, the common options are SPI bus and I2C bus, and the communication overhead of each bus is basically low, which meets the objective requirements of low interference environment. Another option is CAN bus, which is widely used in automotive applications. CAN bus is excellent and has the characteristics of error detection and fault tolerance, but its communication overhead and material cost are high. Although the connection from the battery system to the CAN bus of the car partner is ideal, it is beneficial to use SPI or I2C communication in the battery pack.

After reading the introduction of automobile series, is it necessary for friends to know what batteries are used for electric vehicles? So, do your friends like the knowledge that Bian Xiao Auto introduced to your friends today? Bian Xiao believes that these friends still need to know more about these contents and still need to solve problems for our future life. Finally, I hope that the brief introduction of Bianxiao Automobile can solve the problem for friends.

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