How to test the capacity of lithium battery

At present, in battery market, the lithium battery application is more extensive. Lithium battery has high density, which is five times that of lead-acid batteries. At the same time, compared to lead-acid battery, the lithium battery cycle life increase greatly. Lithium battery charge and discharge times are over 1000. In theory, it can use for ten years, while the lead-acid battery can only use for 3 years, so the later cost becomes less. Lithium battery self-discharge is still very low, and it has no memory effect. The most important part is that it has no pollution. Lithium-ion batteries comply with promoting standards in our country. It is believed that many people use lithium battery, but when we buy lithium battery, how do we check its capacity?

Conventional charging is "two-stage constant current charging, this method does not waste electricity, charging time is short, good for extending the service life of the lithium battery, also it is much easier to calculate the lithium battery capacity. Wind power, is the conventional charging.

The lithium battery capacity configuration is reasonable, directly affect the technical and economic indicators of wind power. Capacity is small, windy when the surplus electricity cannot get full storage. Chosen too large capacity, an increase investment; Second lithium battery charging may be prolonged dissatisfaction status, will affect the efficiency and service life of lithium-ion batteries. Table 1 is for lithium-ion batteries in the situation of wind power equipment investment.

1. The experience calculation method

Pilot according to our experience, under the wind should examine, also can use the following simple formula to estimate the required battery capacity .Which type of:

Q - configuration needed for lithium battery capacity (Ann);

P - load power (watts);

T - daily electricity hours;

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

N - battery reserve cycle coefficient; As to (according to the wind and 3 ~ 8 days)

K - discharge control coefficient, (0.75 ~ 0.8)

On type considered: (1) rated power of electrical equipment, (2) local meteorological condition, namely calm period average time, was to prevent the lithium battery over discharge, discharge should be controlled in a certain degree.

Example, install a 100 - watt machine for 3 household electricity, household furnish 12 v 15 watt bulb 2 only five hours a day on average lighting, calculate the lithium battery capacity configuration required. Control (6 reserve coefficient and discharge coefficient 0.8) generation into the formula:

When choosing six pieces of l2 voltage 48 lithium-ion batteries, the total capacity of 288 ampere hour.

2. The power balance calculation method.

Calculation steps are as follows:

A. according to local meteorological department, the wind speed data provided in ten days for a degree, ten-day respectively by statistical fan wind speed to stop the wind from starting work hours occurred within the scope of the different wind speed.

B. the wind turbines according to choose P = f (V) characteristic curve and wind speed data, computing - machine by ten-day can's electricity, and draw the annual output process curve. Drawn according to wind speed data computing are grazing factory ED1.5-100 type fan power generating capacity of the process line. Calculated the machine under the local wind conditions, power generating capacity is 276 degrees. Capacity change a lot from the process line to see the ten-day, * more in late April 19 degrees, * less in late February, nearly 20 times of only 0.95 degrees, configure lithium battery for energy storage adjustment is necessary.

According to use C telecom conditions, calculated by ten-day electricity consumption, and annual power consumption process line is given. The appended drawings of a dotted line.

D. compare capacity and power consumption process line, for power generation is less than the power difference * time (slash) to determine the required lithium battery capacity. The difference between * power of 2.3 degrees. Need to configure 2300 volt ampere hour battery, 48 Ann when actual use 12 v lithium battery 4 pieces. The total capacity is 2304 volt ampere hour.

Determine the standard cell, must pay attention to: the capacity of the battery oil group should be able to safely accept * current strength of the wind turbine output Imax.

Because of the wind speed change frequently, the motor output current age is small, when, so it is difficult for lithium battery charging current and charging time needed for sure. Aimed at the actual situation, we adopt the following two kinds of calculation method to determine the configuration of lithium battery capacity.

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