纯电动汽车锂离子电池（Pure electric carlithium-ion battery）

1、纯电动汽车 3 锂离子电池（Pure electric car 3 lithium-ion battery）This article is contributed by JesusThe PPT document may not have a good browsing experience at the WAP end. It is recommended that you choose TXT, or download the source file to the native view.Chapter 2 Battery Electric Vehicles (BEV) of pure E

2、lectric Vehicles (Battery Electric car)L pure electric vehicle - lithium ion battery pure electric vehicle - lithium ion batteryWorking schematic of lithium ion batteryWhen the discharge is in the opposite direction, lithium is removed from the carbon material and goes back to the anode, which is ex

3、tremely high in the lithium. Hernia of rechargeable lithium ion from the oxide anode crystal lattice, after passing the organic electrolyte for lithium ion conduction transfer embedded in carbon negative material anode, cathode on rich lithium, lithium anode in a poor state, electronic compensation

4、of electricity at the same time Charge from the external circuit for give to carbon negative, to ensure that the negative electric charge balance; Load balance;Lithium ion battery performanceCompared with the traditional chemical power system, it has the following advantages: 1. The ratio energy of

5、li-ion battery can reach 200Wh/Kg and 300Wh/L, which is about the traditional zinc manganese, lead acid 200Wh/Kg and 300Wh/L, which is about 6 times as much as 6 and nickel-cadmium battery of traditional zinc manganese, lead acid and nickel cadmium battery. 2. Wide working temperature range. Can be

6、in - 200 C - + 750 C ring, working temperature range width. Can work at the temperature of the environment; Work in temperature; 3. Good storage performance. A lithium battery usually can be stored at 53 and storage performance is good. Lithium usually 5 to 10 years in storage batteries, lithium sec

7、ondary battery self-discharge are generally less than 15% (一10 years, lithium secondary battery self-discharge generally less than 15% (one year), about 1/10 of the conventional lead acid, nickel cadmium battery;, about 1/10 of the conventional lead acid, nickel cadmium battery;Lithium ion battery p

8、erformance4. The voltage is 3.6 volts (generally 3.0 volts or above), and the voltage is 3.6 volts or more. The electric voltage is stable; 5. Small self-discharge and long cycle life; Small self-discharge, long service life; 6. No memory effects. At present, as an application trend, li-ion power ba

9、tteries are increasingly being used in electric vehicles. Our lithium ion power battery application in electric vehicles has been included in the national high technology research and development (" 863 "project has been included in the national high technology research and development (&q

10、uot; 863" plan) and the national "tenth five-year plan.The composition of lithium-ion batteriesLithium ion battery is actually a lithium ion concentration cell, positive and negative electrode is composed of two different embedded lithium ion compound, often using lithium compounds the pos

11、itive LiXCoO2 generally USES lithium compounds, Li LiXNiO2 or LiMn2O4 cathode using lithium anode with a carbon layers of compound Li a carbon layers of compound LiXC6, electrolyte for LiPF electrolyte for LiPF6 and LiAsF6 organic solution, by Li ten in organic solvents such as is, by Li round-trip

12、embed the negatively charged electrode and embedded off form the battery charging process and electricity. When charging, Li 10 is embedded with the electrolyte into the negative terminal, which is extremely rich in lithium, and is in a very poor lithium state, which is the reverse of the discharge.

13、A mathematical model for lithium-ion batteriesThe basis of the modeling of li-ion battery is how to determine the electromotive force and internal resistance of lithium ion batteries. These feature functions are determined based on the results of a change in the relationship between the State of Cap

14、acity and the result of the State of Capacity.The charging characteristicsThe charge state value of the lithium ion batteryTwo basic characteristics of lithium ion power battery: the lithium ion power battery two basic characteristics: 1, the capacity of the battery is associated with discharge curr

15、ent, discharge current, the greater the is running down the electricity can release the less effective capacity, this feature or capacity characteristic The less, this feature or 2, the working voltage of the battery capacity characteristics associated with the depth of discharge, let the electric c

16、urrent and discharge depth, the greater the battery voltage drop, the more this feature, we referred to as voltage drop, the more this feature we voltage features for shortThe battery energy model is based on the battery equivalent circuit diagram.The capacity of the battery characteristics will dir

17、ectly affect the electric car trip range of effective, while its voltage characteristic directly undermine the electric vehicle power performance, both relate to each other, mutual influence, constitute the battery (2.7 v to 2.7 v) discharge characteristics. The interaction of the battery (2.7 v-4.2

18、 v) discharge characteristics.Discharge characteristicExperiment found that the lithium ion battery under the condition of discharging termination voltage of 2.7 V, the larger the discharge current of the battery polarization under the condition of 2.7 V, the larger the discharge current of battery

19、polarization, the greater the discharge capacity of the battery is smaller, but the static state voltage and battery discharge depth is the relationship between basic keep unchanged. In the case of a large current discharge (greater than 2C), the discharge curve of the battery appears (greater than

20、2C), and the discharge curve of the battery is reduced and then increased.The instanceUnder 25 , with no rate constant current charge battery monomer to 4.2 V to 4.2 V after, constant voltage charging, when the charging current is small in the constant current charging electric current stops chargin

21、g 10% %,The instanceFrom figure 1 a shows: from figure 1 a shows: monomer battery charging curve can be divided into constant current charge and the constant voltage charging, charging and constant voltage charging two parts, with the increasing of charging current, monomer proportion of constant-cu

22、rrent charging your battery capacity reduction, constant monomer proportion of constant-current charging your battery capacity reduction, voltage charge capacity proportion increase; The proportion of charging capacity increases; With the increase of the charging ratio, the voltage rise rate of the

23、single-cell constant current charging process accelerates, the rate is accelerated and the charging platform is raised. When the charging ratio is 7.0 C, it is not possible to see the LiMn platform when the LiMn2O4 feature is completely invisible, mainly due to the increase of electrochemical polari

24、zation due to the high multiplier charge.The instanceFrom figure 1 b: monomer battery under different ratio of discharge curve 1 b: the shape of the basic similar, early discharge and close at the end of the voltage drop quickly, middle discharge voltage change smaller, present a set level. The 1.0

25、C discharge platform of the single battery was kept at 3.85. One of the monomer batteries.When the terminal voltage of the electric pool is lower than the discharge termination voltage of the battery, the discharge of the battery should be stopped immediately.Super capacitorDue to the frequent start

26、 and stop of electric vehicles, the discharge process of the accumulator is very large. In normal driving, electric cars from battery very low average power, and is of very high peak power and when accelerating or climbing a hill, a high-performance electric cars, peak power and the ratio of average

27、 power can be up to now. The peak power and average power ratio of high-performance electric vehicles can reach 16:1. For the energy consumption when accelerating or climbing a hill account for two-thirds of the total energy consumption, in the existing used to consume energy when accelerating or cl

28、imbing a hill account for two-thirds of the total energy consumption, under the condition of the existing battery technology, storage battery must be than energy and power, and make a balance between power and cycle life, and difficult to on an energy system At the same time the pursuit of specific

29、energy, specific power and long life. In order to solve the trip range of electric cars and accelerating the contradiction between the climbing performance, can consider to use two sets of energy systems, including travel distance by the main energy provides the best, and by the auxiliary help energ

30、y in providing short auxiliary power when accelerating or climbing a hill. The energy of the auxiliary power system can be directly used for autonomous energy, or it can be used to recover the renewable kinetic energy when the electric vehicle brakes or downhill. The selection of supercapacitors for

31、 auxiliary energy has attracted wide attention.Features of supercapacitorsIn the near term, supercapacitors are so much lower than energy that it can't be used as an energy source for electric vehicles alone, but the use of ultracapacitors as a supplementary energy source has significant advanta

32、ges. The best combination used on electric vehicles is the battery & supercapacitor hybrid energy system, which separates the electric vehicle from the power and power requirements of the battery. Battery design can focus on the consideration of energy and cycle life requirements without having

33、to think much about power issues. Due to the load balancing of supercapacitors, the discharge current of the battery is reduced so that the available energy and service life of the battery can be significantly improved. And compared with batteries, supercapacitors can quickly and efficiently absorb

34、the regenerative kinetic energy generated by electric vehicle braking. Due to the load balance and energy recovery of supercapacitors, the continuous mileage of vehicles has been greatly improved. But the system response to the battery and super capacitor, motor and power inverter for comprehensive

35、control and optimization match, the power converter and its controller design should fully consider the matching between the motor and super capacitor.Ultra high speed flywheelUltra-high speed flywheel is the realization of electric vehicle energy storage requirements of an effective way, it has a specific energy, specific power, long cycle life, high energy efficiency, can fast charge, free m