16340 battery

Research and application of 16340 battery in photovoltaic power generation systems

In early photovoltaic power generation systems, open-type lead-acid batteries were generally used as energy storage devices. However, open-type lead-acid batteries require the addition of acid and water for maintenance, and the acid easily pollutes the environment. This is not conducive to unattended use and environmental protection. In recent years, valve-regulated sealed lead-acid batteries (VRLA) have become very popular because they are sealed and do not leak acid and do not corrode equipment and pollute the environment. They are widely used in my country's telecommunications, electric power, railway and other industries. The batteries used in current photovoltaic systems are almost all 16340 battery. The main functions of 16340 battery are twofold: (1) At night or when it is cloudy and when the photovoltaic array production capacity and load power consumption are inconsistent, the battery can store excess energy or provide energy to the load; (2) Due to the working characteristics of solar cell components Affected greatly by solar irradiance, temperature, etc., the load is often not near the optimal operating point. The battery has a clamping effect on the operating voltage of the solar cell, which can ensure that the load is near the optimal operating point.

The composition of photovoltaic power generation system

Photovoltaic power generation system is a power generation system that uses the principle of photoelectric effect to convert solar energy into electrical energy. It usually consists of solar cell components, controllers, battery packs, DC/AC inverters, etc.

The function of the solar cell module is to convert solar energy into electrical energy, supply the load or charge the battery bank; the function of the controller is to protect the charging and discharging of the battery bank; the battery bank is used to store electrical energy; the function of the inverter is to convert DC power Convert to alternating current. At night or on rainy days, when the solar cell module cannot work, the battery pack supplies power to the load. It can be seen that the battery pack plays a very important role in the photovoltaic power generation system.

Characteristics of 16340 battery for photovoltaic power generation systems

1How the battery used in photovoltaic power generation system works

The working mode of the battery can be divided into two types: recycling use and float charging use. If the battery is often in a state of frequent charging and discharging, that is, it is used cyclically; if it is often in a charging state, it is used in float charge, which can make up for the capacity loss caused by the battery's self-discharge. 16340 battery used in photovoltaic power generation systems are recycled.

2Charging and discharging characteristics of batteries used in photovoltaic systems

The charging and discharging characteristics of batteries used in photovoltaic power generation systems generally have four points: (1) charging during the day and discharging at night and on cloudy and rainy days; (2) low charging rate, the average charging current is generally 0.01~0.02C, rarely reaching 0.1~0.2C ; (3) The discharge current is small, and the discharge rate is usually 0.004~0.05C; (4) One charging time is short, even if it is long, it is only about 10 hours. Photovoltaic systems rarely charge batteries completely and quickly, and batteries often remain undercharged.

3 Performance requirements of 16340 battery for photovoltaic power generation systems

Photovoltaic power generation systems are mostly built in remote mountainous areas, plateaus, and Gobi. The natural environment is very harsh, and the working environment temperature varies widely. Therefore, the following requirements are required for batteries in photovoltaic power generation systems: (1) Deep cycle discharge performance and long charge and discharge cycle life; (2) Strong overcharge resistance; (3) Strong capacity recovery ability after overdischarge; (4) ) Good charging acceptance ability; (5) When the battery is used in a static environment, the electrolyte is not easy to stratify; (6) It has maintenance-free or low-maintenance performance; (7) It should have good high and low temperature charge and discharge characteristics; (8) It can adapt to the use environment in high-altitude areas; (9) Each battery in the battery pack has good consistency.

In early photovoltaic power generation systems, open-type lead-acid batteries were generally used as energy storage devices. However, open-type lead-acid batteries require the addition of acid and water for maintenance, and the acid easily pollutes the environment. This is not conducive to unattended use and environmental protection. In recent years, valve-regulated sealed lead-acid batteries (VRLA) have become very popular because they are sealed and do not leak acid and do not corrode equipment and pollute the environment. They are widely used in my country's telecommunications, electric power, railway and other industries. The batteries used in current photovoltaic systems are almost all 16340 battery. The main functions of 16340 battery are twofold: (1) At night or when it is cloudy and when the photovoltaic array production capacity and load power consumption are inconsistent, the battery can store excess energy or provide energy to the load; (2) Due to the working characteristics of solar cell components Affected greatly by solar irradiance, temperature, etc., the load is often not near the optimal operating point. The battery has a clamping effect on the operating voltage of the solar cell, which can ensure that the load is near the optimal operating point.

The composition of photovoltaic power generation system

The function of the solar cell module is to convert solar energy into electrical energy, supply the load or charge the battery bank; the function of the controller is to protect the charging and discharging of the battery bank; the battery bank is used to store electrical energy; the function of the inverter is to convert DC power Convert to alternating current. At night or on rainy days, when the solar cell module cannot work, the battery pack supplies power to the load. It can be seen that the battery pack plays a very important role in the photovoltaic power generation system.

Characteristics of 16340 battery for photovoltaic power generation systems

1How the battery used in photovoltaic power generation system works

The working mode of the battery can be divided into two types: recycling use and float charging use. If the battery is often in a state of frequent charging and discharging, that is, it is used cyclically; if it is often in a charging state, it is used in float charge, which can make up for the capacity loss caused by the battery's self-discharge. 16340 battery used in photovoltaic power generation systems are recycled.

2Charging and discharging characteristics of batteries used in photovoltaic systems

The charging and discharging characteristics of batteries used in photovoltaic power generation systems generally have four points: (1) charging during the day and discharging at night and on cloudy and rainy days; (2) low charging rate, the average charging current is generally 0.01~0.02C, rarely reaching 0.1~0.2C ; (3) The discharge current is small, and the discharge rate is usually 0.004~0.05C; (4) One charging time is short, even if it is long, it is only about 10 hours. Photovoltaic systems rarely charge batteries completely and quickly, and batteries often remain undercharged.

3 Performance requirements of 16340 battery for photovoltaic power generation systems

Photovoltaic power generation systems are mostly built in remote mountainous areas, plateaus, and Gobi. The natural environment is very harsh, and the working environment temperature varies widely. Therefore, the following requirements are required for batteries in photovoltaic power generation systems: (1) Deep cycle discharge performance and long charge and discharge cycle life; (2) Strong overcharge resistance; (3) Strong capacity recovery ability after overdischarge; (4) ) Good charging acceptance ability; (5) When the battery is used in a static environment, the electrolyte is not easy to stratify; (6) It has maintenance-free or low-maintenance performance; (7) It should have good high and low temperature charge and discharge characteristics; (8) It can adapt to the use environment in high-altitude areas; (9) Each battery in the battery pack has good consistency.

Design method of lead-acid battery capacity for photovoltaic power generation system

To determine the battery capacity, you must first determine how much power the load connected to the system requires every day; secondly, how many days of power the battery needs to store based on climate conditions. When determining the battery capacity, the larger the capacity, the better. Excessive battery capacity will also cause problems. This is because when there is insufficient sunlight, the battery pack may remain in a partially charged state. This undercharged state will lead to increased sulfation of the battery, reduced capacity, and shortened life. The general calculation formula for battery capacity is C=E·t/(D·η0·η1)(1)

In the formula, C is the capacity of the battery; E is the average daily power consumption of the load; t is the longest number of hours without sunshine; D is the allowable discharge depth of the VRLA battery; eta0 is the charging and discharging efficiency of the VRLA battery; eta1 is the inverter conversion efficiency.

Performance improvement of 16340 battery for photovoltaic power generation systems

Battery failure and short life are one of the reasons that hinder the promotion of photovoltaic power generation systems. The life of 16340 battery will gradually shorten after being used in photovoltaic systems. The main factors that affect its life include: limited charging time, long-term undercharging; low current discharge; overcharging; temperature, etc. According to the special requirements of the photovoltaic power generation system for battery performance, combined with the above-mentioned factors affecting battery life, a series of performance improvements were made on the basis of the original VRLA battery. Specific improvement measures include the following aspects: (1) Improve cycle service life. In order to extend the cycle life of 16340 battery, the corrosion layer formed by the grid alloy at the interface between the grid and the active material should have good conductivity, and the grid should have creep resistance. The battery design adopts tight assembly and appropriately increases the assembly pressure.

(2) Improve battery charging acceptance capability. For 16340 battery, undercharging is more harmful to the battery than overcharging, so it is particularly important to improve the charging acceptance of 16340 battery. High-stability expansion agents and conductive additives are added to the negative electrode paste formula to improve charge acceptance.

(3) Improve over-discharge performance. Reducing the specific gravity of the sulfuric acid electrolyte and adding special electrolyte additives can reduce corrosion of the plates, reduce the occurrence of electrolyte stratification, and improve the battery's charge acceptance and over-discharge performance.

(4) Use a special safety valve. For plateau areas, due to the low atmospheric pressure, the safety valve pressure value is specially adjusted.

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