Method for detecting the capacity of lithium batteries

At present, in the battery market, the application of lithium batteries is also more and more extensive. Lithium batteries have a high density, five times that of lead-acid batteries. At the same time, the life of lithium batteries is also greatly increased compared to lead-acid batteries. The number of charges and discharges of lithium batteries is 1,000 times. Theoretically, it can be used for 10 years, while lead-acid batteries can only be used for 3 years. In this way, it will save a lot from future costs.. The self-discharge of lithium batteries is still very low and there is no memory effect. :: An important element is that lithium batteries are pollution-free and conform to our standards of advocacy. I believe that many people have used lithium batteries, so when we buy lithium batteries, how do we determine its capacity?

General conventional charging is "two-phase constant current charging". This method does not waste electricity, and the charging time is short, which is beneficial for extending the service life of lithium batteries. At the same time, it is much easier to calculate the capacity of lithium batteries. Wind power is different from conventional charging.

The rational configuration of lithium battery capacity directly affects the technical and economic indexes of wind power generation. The capacity selection is small, and the excess power emitted when windy is not fully stored. The capacity selection is too large, one increases the investment; Second, lithium batteries may be in a state of long-term charging dissatisfaction, which will affect the efficiency and service life of lithium batteries. Table 1. Investment of lithium batteries in wind power generation equipment.

1. Empirical calculation

Based on the experience of our pilot, the following formula can also be used to easily estimate the required battery capacity. In the equation:

Q-The required lithium battery capacity(Anshi);

P -- Load power(watts);

T -- number of electric hours per day;

U-standard lithium battery voltage(generally 12 volts);

N-Battery reserve cycle coefficient; (According to the wind conditions, generally take 3 to 8 days)

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

The above formula takes into account: 1 The rated power of electric equipment, 2 The local meteorological conditions, that is, the average time of no wind period, 8. In order to prevent the over-discharge of lithium batteries, the discharge should be controlled to a certain extent.

For example, a 100-watt machine is installed for 3 households to use electricity. Each household is equipped with 12 volts and 15 watts of light bulbs. Two bulbs are illuminated for an average of 5 hours per day to calculate the required lithium battery capacity. (The reserve coefficient is taken 6 and the discharge control coefficient is taken 0.8) into the formula:

Select 6 L2 Volt 48 angstroms of lithium batteries with a total capacity of 288 angstroms.

2. Electric balance calculation method.

The calculation steps are as follows:

A. According to the wind speed data provided by the local meteorological department, the number of hours of wind speed from the start of fan operation to the different wind speeds within the range of the shutdown wind is measured in ten days.

B. According to the P = F(V) characteristic curve and wind speed data of the selected wind turbine, the amount of electricity that can be emitted by the station machine for each day is calculated, and the annual power generation process curve is drawn. Based on the calculation of wind speed data, the annual power generation process line of the commercial animal husbandry factory ED1 .5 ~ 100 fan is drawn. It was calculated that the annual power generation of the aircraft was 276 degrees under the local wind conditions. From the process line, it can be seen that the power generation of each generation varies greatly. * More than 19 degrees in late April and only 0.95 degrees in late February, a difference of nearly 20 times, indicating that the deployment of lithium batteries for energy storage is necessary.

C According to the power supply, calculate the power consumption for the first time, and give the process line for the annual power consumption. The figure shows the dotted line.

D. Compare the power generation and power consumption process lines to determine the required lithium battery capacity for periods of power generation that are less than the power difference *(in the slash section of the figure). The difference * was 2.3 degrees. It needs to be equipped with 2300 Volt batteries, and 12 Volt 48 Volt lithium batteries are actually used. Total capacity of 2304 Volt.

When determining the standard battery, it must be noted that the capacity of the storage oil group should be safe to accept the * current strength Imax output of the wind turbine.

Due to the frequent change in wind speed, the current output of the motor is small and small, and it is sometimes not available. This makes it difficult to determine the charging current and the required charging time of the lithium battery. In view of this situation, we use the following two calculation methods to determine the configuration of lithium battery capacity.

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