Electric bicycles and electric motorcycles have become important means of transportation for large, medium and small cities, and are generally accepted by people. Since electric vehicles are generally more expensive than conventional bicycles, the service life has become a major concern. In fact, the battery is one of the core components of the electric bicycle, and the service life of the battery largely determines the service life of the electric vehicle. Therefore, strengthening the maintenance of the battery will extend the service life of the battery. It is understood that the batteries used in electric vehicles are lead-acid batteries. For the maintenance of lead-acid batteries, a series of suggestions are given below, including a total of eight small defects.
Charging
Lead-acid batteries have no memory. The reason why the capacity is rapidly reduced is mainly due to some reasons such as battery vulcanization and "water loss" and "debt loss". The battery is most afraid of "depletion" undervoltage, and the battery is often "depleted". The board is extremely vulnerable. In reality, up to 70% of the electric vehicle battery capacity is reduced by the strong current (starting current) when the electrode plate is discharged (especially for electric motorcycles), and the electrode plate strain is a physical damage of the battery. The damage cannot be repaired. Therefore, "every day with the car, every day charging", to ensure that the battery has sufficient voltage at any time becomes inevitable.
Regularly replenish distilled water
Users generally believe that maintenance-free batteries do not need to add water, in fact, this statement is wrong. Maintenance-free batteries generate heat during charging and high-current discharge. If there is heat, water will evaporate. Although the process of water evaporation is very slow, the amount of accumulated water evaporation cannot be ignored for a long time. Therefore, the battery should be replenished once every 6 months or so, so that the service life of the battery will be prolonged.
Electric car start
The starting current of the electric vehicle is very large, especially the electric motor of the high-power motor, and the starting current is larger. The high current is very harmful to the battery plate. The best way is to start the electric car before riding, just like riding a bicycle.
Battery discharge
After the battery is used for a period of time, some active substances will inevitably sink. If the active substances are not activated in time, it will inevitably have some impact on the capacity of the battery. Therefore, when using the electric vehicle frequently, it is necessary to make the battery every season. Depth discharge once.
charger
The charging process of the new battery is generally 6-8 hours. When the battery is fully charged, the charger will light green. If the charging time is too long, check if the charger voltage protection device is damaged. If it is damaged, you need to change the charger in time. Otherwise it is easy to charge the battery. In addition, the charger should not buy a fast charger, and fast charging also has damage to the battery plate.
Not used for a long time
The purpose of this is to prevent the battery from being placed for too long and causing the battery to vulcanize and "deplete".
Prevent battery explosion
Explosive exposure will increase the battery temperature and greatly shorten the battery life.
Battery protector
The battery protector is also a pulse generator. The pulse is uninterrupted to eliminate the vulcanization of the battery, so that the plate is always kept "clean", thereby achieving the effect of prolonging the service life of the battery, but it has little effect on the damage of the battery plate by the large current.
clean
If the battery is not cleaned in time, it will easily affect the battery life and power supply. Simply put, a battery is an electrochemical device that converts chemical energy into electrical energy. Keeping the battery working properly, battery cleaning is essential. The oxidation reaction between the pole and the chuck of the battery is easy to occur, and the metal parts of the chuck portion can be severely rotted.
Ordinary lead-acid batteries, pay special attention to the usual cleaning work. Pay attention to check whether the pole and the chuck are tightly connected, if there is any corrosion and burning, and if the vent hole is blocked or not, and if the electrolyte is reduced, if it is found, it should be disposed of in time. When starting the car, the start time should not exceed 3 to 5 seconds, and the restart interval should be no less than 10 seconds. If the car is not used for a long time, the car should be fully charged. At the same time, the car will be launched once every other month and keep running at a medium speed for about 20 minutes. Otherwise, the placement time is too long and it will be difficult to start. General maintenance-free batteries should also be checked frequently, and problems should be replaced in time.
Maintenance-free batteries are now available in most cars. These batteries do not require the addition of distilled water during use. The terminals do not corrode, have less self-discharge and have a long life. However, if it is not checked in time, the battery is not clear to the owner of the scrapping period, which will also affect the normal operation of the car.
Lead acid battery in electric vehicle applicationsLead-acid batteries are used in a wide range of applications and play an important role in forklifts, electric vehicles and large uninterrupted power supply systems. Efficiently detect the current, cell voltage and overall voltage of the lead-acid battery in the electric vehicle, provide accurate parameters for estimating the charge state of the battery, improve battery safety monitoring and management, and ensure battery reliability and efficiency.
1 lead-acid battery management system overview
The lead-acid battery management system is designed by Philips' high-performance, intelligent microcontroller integrated circuit chip, which is the core material of the management system control. It is a complementary metal oxide semiconductor manufacturing process and is widely used in the electric vehicle industry. According to the characteristics of lead-acid battery, the electric vehicle battery charge and discharge current, the depth of discharge, the regenerative brake feedback current and voltage are monitored to avoid excessive loss during battery charging and discharging, and to monitor the charge and discharge state. Select the appropriate charging and discharging mode to balance the battery unit work, reduce potential constraints in battery management, and improve battery performance.
2 Lead-acid battery management system function
According to the layout and structural characteristics of the electric vehicle lead-acid battery, the management system is generally applicable to the number of single cells, and the electric vehicle lead-acid battery unit is relatively dispersed. The management system refers to the distributed battery management system. The battery information is collected by the sub-nodes. The control unit collects the parameters such as the temperature and voltage of the battery standard package, and sends the bus battery information to the management system processing center.
3 Battery management system application
3.1 Temperature collection
In the temperature management circuit, the battery management system uses a heat-conductive adhesive adhesion device. The surface temperature of the battery and the temperature of the die are different, generally in the range of 0.1 degrees Celsius. When the measured battery temperature is different from the ambient temperature, the data is transmitted to the controller for processing through the bus, and the process of converting the temperature into a digital signal is completed. By controlling the feedback from the system and automated measurements, the back and leads of the device are simultaneously isolated from the air.
3.2 Control charging and discharging
The control charging and discharging module can be used for charging and discharging management with large intelligent power. It is an advanced hybrid power device that is directly connected to the battery management system host, and is composed of a driving circuit and a protection circuit. The internal setting is overvoltage and current overheating. The fault real-time detection circuit can effectively protect the battery usage function. It is connected with the external power grid management system to realize charging and discharging of the vehicle battery, and charging the battery current of different stages according to the control circuit command or the flag bit. After the battery is full, the charging information is fed back to the management system in time to complete the automatic power-off. It is highly intelligent.
Battery circuit diagram 1:
3.3 alarm and power output indication
In the battery management system, the alarm and power output are generally composed of a module and a simple keyboard. The various detection parameters are set, and the voltage and current data of the battery cells are collected on the system display, and the data is comprehensively managed. These data values ​​are analyzed, and the charge and discharge strategy is analyzed. By transmitting a charge and discharge control instruction command to each node, the temperature and state are displayed, thereby realizing human-computer interaction management. Online input processing scheme on the management system software, continuous judgment processing and status confirmation of the simple button according to requirements, button release representative to complete this step, thereby improving the system optimization performance.
3.4 Control Single Chip Operation
After the lead-acid battery management system is started, it needs to perform the initialization operation procedure of the management system to efficiently control the operating parameters of the single-chip. After the battery is charged and discharged, the system will automatically read the sensor temperature data, use the A/D program to obtain accurate ten-bit current and voltage signal data, and then transmit the data information to the system. The system can respond to the battery to determine the operating status of the battery. Different operating states correspond to different processing procedures. The data represented by the operating status is also output on the digital display of the system. During the operation, the management system compares the data that has been input with the monitoring real-time data, so as to automatically correct the parameters, realize the intelligent adjustment of the internal parameters of the battery, and improve the efficiency of the management system.
3.5 Evaluation of battery charge status
Battery series circuit diagram 2:
When the steady current discharges the battery, the management system will automatically judge the battery charge state and perform real-time operation estimation on the battery charge to maintain the battery good effect. However, in the process of charging the battery with the actual variable current, since the linearity is relatively poor, the current varies greatly, and a serious deviation occurs. Therefore, the battery management system strictly calculates the battery state, obtains the DC internal resistance and the battery charge to determine whether to perform the throttle] shutdown (including braking and slowing down), and analyzes the battery state of charge to more accurately determine the battery performance. .
4 Conclusion
The electric vehicle lead-acid battery management system is the key point for connecting the power battery and the electric vehicle. The application of the battery management system has a great effect on improving the reliability and battery performance of the electric vehicle. It has intelligent features, accurate data measurement, timely feedback, and improved battery self-protection. It also has great advantages in improving power supply stability and helping to maintain battery efficiency and service life.
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