Battery: important equipment in wind power generation

In the small wind power generation equipment, the battery is one of the important auxiliary equipment. Accumulator plays an important role in storing electric energy and stabilizing voltage in dc power supply system.

I. determination of battery capacity

Whether the battery capacity configuration is reasonable or not directly affects the technical and economic indicators of wind power generation. Capacity selection of small, when the wind sent by the surplus power can not be fully stored. If the capacity is too large, the first is to increase investment. The second battery may be in a state of long-term charging dissatisfaction, will affect the efficiency of the battery and service life. Table 1 shows the investment of batteries in wind power generation equipment.

General conventional charging is "two-stage constant-current charging", this method neither wastes power, short charging time, prolonging the service life of the battery, but also much easier to calculate the battery capacity. Wind power, on the other hand, is different from conventional charging.

Because the wind speed often changes, the output current of the motor is sometimes large, sometimes small, sometimes not, so that the battery charging current and required charging time is difficult to determine. In view of this practical situation, we use the following two calculation methods to determine the configuration of battery capacity.

1. Electric quantity balance calculation method.

The calculation steps are as follows:

A. According to the wind speed data provided by the local meteorological department, the wind speed within 10 days is taken as one degree, and the number of hours from the starting wind speed of the fan to the stopping wind speed within the range is calculated on a 10-day basis.

B. According to the P=f(V) characteristic curve and wind speed data of the selected wind generator, calculate the amount of electricity that can be generated by each machine, and draw the process curve of its annual power generation. Figure -- is the annual power generation process line of the ed1.5-100 type fans in shangdu mu machine factory calculated and drawn based on the wind speed data of the right rear banner of Inner Mongolia. It is calculated that the machine in the local wind conditions, the annual power generation is 276 degrees. It can be seen from the process line that the generation capacity of each ten-day period varies greatly, the most is 19 degrees in late April, and the least is only 0.95 degrees in late February, with a difference of nearly 20 times, indicating that it is necessary to configure batteries for energy storage adjustment.

C calculates the electricity consumption by ten days according to the situation of telecommunication, and gives the process line of annual electricity consumption. The dotted line is shown in the attached figure.

D. Compare the process line of power generation and electricity consumption, and determine the required battery capacity by the electricity amount in the period when the power generation is less than the maximum power difference (the oblique part in the figure). The maximum power difference in the figure is 2. 3 degrees. It needs to be equipped with 2300 volt-ampere-hour battery, and 4 batteries of 12 volts and 48 ampere-hours are actually selected. Total capacity 2304 voltampere hours.

2. Empirical calculation method

Based on our pilot experience, the following formula can also be used to easily estimate the required battery capacity under the wind conditions in youhou banner and shangdu area. Q -- required capacity of battery (ampere hour);

P -- load power (watt);

T -- daily hours of electricity;

U -- standard battery voltage (generally 12 v);

N -- battery reserve cycle coefficient; (determined according to wind conditions, generally 3 to 8 days)

K -- discharge control coefficient, (0.75~0.8)

The formula is considered: (1) the rated power of the electrical equipment, (2) the local meteorological situation, is the average time of no wind period, in order to prevent the battery has been discharged, the discharge should be controlled in a certain degree.

Take the example of chayu back banner, a 100-watt machine is installed to provide electricity for 3 households. Each household is equipped with 12 volt and 15 watt light bulbs, 2 of which light for 5 hours per day on average. The required battery capacity is calculated. (reserve coefficient is set at 6, discharge control coefficient is set at 0.8).

Six l2-volt 48 ampere-hour batteries with a total capacity of 288 ampere-hours were selected.

When determining a standard battery, it is important to note that the capacity of the storage oil group should be safe enough to accept the maximum current intensity Imax of the wind turbine output.

Second, the operation of the battery

1. Full charge and full release. Namely fan centralized installation, centralized charging, battery scattered to households, each household two battery rotation.

Wind power generation is subject to wind constraints, especially for small wind turbines. In the small wind in the village, the fan must be installed in the village, line and difficult rural, hot, suitable for this way. Wind turbines can be set up in a better wind site, to make full use of wind energy. Battery rotation ensures full and full discharge. The disadvantage is that:

More battery required, increase the investment and electricity cost.

Battery efficiency is low (about 40%).

(3) the battery charge and discharge rotation frequently, the service life is short.

(4) often back and forth to carry the battery to cause trouble to the user, and easy to damage the battery; Careless handling, easy leakage of electrolyte,

Can cause battery drain or burn clothing.

2. Semi-floating charging operation mode. Is the fan (dc power generation) and battery parallel power supply mode. When not in use (during the day), the fan generates electricity to charge the storage battery; When there is no wind, the battery supplies power to the load; When there is wind, the fan is used to generate floating storage battery and supply power. This method is mostly used for single 1-3 households, the configuration of the blackberry battery capacity is less, the investment is also reduced. The life of the semi-floating battery is generally longer. The service efficiency of the battery is about 50%.

3. Full floating charging system. The battery is centrally installed in the charging room, and the battery pack and the wind generator are connected to the load circuit, so that the battery is usually charged at a low current. When the fan supplies power to the load, the voltage fluctuation caused by the wind speed fluctuation plays a stabilizing role through the battery, ensuring the normal power supply. This mode of operation of the battery life than the above two ways are long, and the required battery capacity is greatly reduced, energy efficiency, simplified battery maintenance, the efficiency of the entire power supply equipment can reach 60-70%. This is how the wind farm at hanbeila, on the right, works.

Three, the battery type selection

There are many types of batteries, wind power generation commonly used in lead-acid charged batteries. After the battery priming, after 30 minutes, stay liquid temperature for l5 ℃ can be used, do not need to undertake initial charge. For the remote places that have just installed wind turbines but do not have the conditions for initial charging, it is very advantageous to use electricity immediately. The disadvantage of this kind of battery is that it is large in size and weight and inconvenient to carry. The market sales of alumina acid battery is a motor vehicle starting battery, its plate structure and manufacturing characteristics, the use of wind power generation in the charging and discharging operation conditions, is not suitable, short life, generally only about 2 to 3 years. In a large wind farm capacity, had better use fixed type flame-proof type lead acid storage battery, the battery has a large capacity, electro-hydraulic proportion is low (around 15 ℃ about 1.21), reduce the corrosion to the plate and baffle plate, can prolong the evaporation time, and seepage prevention measures, reduce the discharge to the ground.

Alkaline batteries are small in size. Light weight, service life up to 15 years or so, there are a small amount of use in our district. Alkaline battery life than acid battery 5-7 times, but its price is 10 times higher than acid battery. In terms of economy, we think it is more advantageous to use lead-acid batteries in small wind power generation.

Four, the impact of battery life reasons

1. In the charging process, with the increase of charging time, the battery electromotive force E increases correspondingly. At the end of charging, if the terminal voltage V remains unchanged and the battery electromotive force E reaches the same value as V, that is, the battery internal resistance Y pool also drops to a very small level, so the I charge should also be very small. This is the correct way to charge the battery itself.

And wind power in charge, is not stable for a long time continuous charging current, charging cannot be carried out in accordance with the certain charge rate, but by the size of the wind to dominate the discretion of the charging voltage, electric current is too large, even in the presence of charging will eventually period, not only to loss of electric energy by generators, and because the electro-hydraulic strong boiling, steaming ranks, electro-hydraulic temperature is too high, can make battery plate active substances hit and accelerate loss, thereby reducing the service life of battery.

2. Due to the user's lack of relevant knowledge, the correct use and maintenance of the battery is poor, the degree of charge and discharge is not well mastered, often occur over charge and over discharge phenomenon, and add distilled water is not timely, resulting in partial plate vulcanization. Or do not pay attention to the liquid temperature when adding liquid (when filling a new battery), make the battery liquid temperature rise very high, produce excessive bubble boiling, speed up the movement, increase the kinetic energy, will seal adhesive burst, lead to premature loss of the active material polar plate, these are the main reasons affecting the life.

3. The battery manufacturing quality is poor, its structure and electrical performance is not suitable for the requirements of wind power generation conditions, but also to reduce the service life.

Five, the correct use and maintenance of the battery

In the small wind power generation, the battery cost accounted for the total cost of 24~46%, annual depreciation cost accounted for more than 50% of the total cost, this is due to the high price of the battery, short service life. Therefore, to strengthen the use of battery maintenance, prolong its life, is a very important issue. The calculation shows that the cost per KWH can be reduced by more than 0.13 yuan by extending the battery life by one year.

In order to improve the service efficiency of the battery and extend its life, the following must be done in the use:

1. To understand the characteristics of lead-acid batteries, use and maintain them in strict accordance with the product manual

2. The electro-hydraulic must be prepared with chemical pure sulfuric acid and qualified distilled water, in a cold place, when the liquid temperature 15 ℃ in proportion should be 1.285.

3. The battery liquid level shall be 10-15mm higher than the plate. When using, it is necessary to add distilled water if the liquid level is too low.

4. Before wiring, strictly check whether the positive and negative sign of the battery is correct and whether the single cell battery has negative phenomenon.

5. It is better to charge the battery for 3 to 4 hours after the first liquid injection before use, which will be more beneficial to its performance. Non-dry charge batteries must be charged before use.

6. Electro-hydraulic temperature should be kept at 20 ℃ or so, even if the fluid temperature electricity in the charging process is no more than 35 ℃. Especially in the winter to pay attention to frost. According to information, when the change of the electric liquid temperature 35 ℃ in 10 a range, every raise or lower 1 ℃, the capacity of the battery about corresponding increase or decrease 0.8% of the rated capacity.

7. If the liquid is not used within 12 hours after being filled, or it is idle for a long time after being used, it shall be recharged according to the regulations before being put back into use. Source: tede. Cn

8. Always screw on the glue plug of the liquid injection port, but make the vent hole unblocked so that the vapor can escape. To keep the battery dry and clean, avoid self-discharge battery.

9. Electro-hydraulic specific gravity drops to 1. At 175, stop using and charge immediately.

10. Wire clips made of the same material as the battery pole note shall be used. If copper material clips are used, a thin layer of vaseline or butter shall be applied to prevent corrosion.

11. Metal objects and tools shall not be placed on the battery to prevent short-circuit between electrodes.

12. No open fire or electrical equipment that can generate electric spark is allowed in the charging room to prevent fire.

Reduce the power efficiency, improve the power efficiency, simplify the battery maintenance, the efficiency of the whole power supply equipment can reach 60-70%. This is how the wind farm at hanbeila, on the right, works.

Six, the battery type selection

There are many types of batteries, wind power generation commonly used in lead-acid charged batteries. After the battery priming, after 30 minutes, stay liquid temperature for l5 ℃ can be used, do not need to undertake initial charge.

The page contains the contents of the machine translation.