Important factors and precautions affecting the service life of  lead-acid battery

Important factors and precautions affecting the service life of lead-acid battery

Lead-acid battery is an important part of UPS system. Its quality is directly related to the reliability of the whole UPS system. No matter how advanced the ups design is and how complete the functions are. Once the lead-acid battery fails, the best UPS cannot supply uninterrupted power. Do not choose low-quality lead-acid batteries for the sake of cheapness, which will affect the reliability of the whole UPS system and cause greater losses.

 

The lead-acid battery is the part with the shortest mean time between failures in the whole UPS system. If it can be used and maintained correctly, its service life can be prolonged, on the contrary, its service life will be greatly shortened.

Important factors affecting the service life of lead-acid battery

 

Ambient temperature

If the ambient temperature is too high, the lead-acid battery will be overcharged and gas will appear. If the ambient temperature is too low, the lead-acid battery will be under charged, which will affect the service life of the lead-acid battery.

 

Discharge depth

The deeper the discharge depth of the lead-acid battery, the less the number of cycles. Therefore, deep discharge shall be prevented during use.

 

Self discharge

During storage, transportation and installation, the lead-acid battery will lose part of its capacity due to self discharge. Therefore, after installation and before putting into use, the remaining capacity of the lead-acid battery should be judged according to the open circuit voltage of the lead-acid battery. Then, different methods are used to recharge the lead-acid battery. The standby storage lead-acid battery shall be recharged every 3 months. The quality of the lead-acid battery can be judged by measuring the open circuit voltage of the lead-acid battery.

 

Charging voltage

Because UPS lead-acid battery belongs to standby working mode. Under normal conditions, it is in the charging state, and it will discharge only when the power is cut off. In order to prolong the service life of the lead-acid battery, the charger of UPS is generally controlled by constant voltage and current limiting. After the lead-acid battery is full, it will turn to floating charge. If the charging voltage is too high, the lead-acid battery will be overcharged, otherwise the lead-acid battery will be undercharged.

 

Lead-acid battery overcharge

The lead-acid battery will not appear any gas during normal use, but if the user uses it improperly, resulting in overcharging of the lead-acid battery, gas will appear. At this time, the internal pressure of the lead-acid battery will increase, and the pressure valve on the lead-acid battery will be pushed open, which will seriously burst the lead-acid battery. During the operation of UPS, pay attention to monitor the terminal voltage value of lead-acid battery pack, floating charge current value, voltage value of each lead-acid battery, ground resistance and insulation state of lead-acid battery pack and DC bus.

 

Storage location

The lead-acid battery shall be installed in a clean, cool, ventilated and dry place as far as possible, and shall be protected from the influence of sunlight, heater or other radiant heat sources. The lead-acid battery shall be placed upright without inclination. The terminal connection between each lead-acid battery shall be firm.

 

Regular maintenance

The lead-acid battery shall be checked regularly after one press. For example, observe whether the appearance is abnormal, measure whether the voltage of each lead-acid battery is average, etc. If there is no power failure for a long time, the lead-acid battery will always be in the charged state, which will make the lead-acid battery activity worse. Therefore, even if there is no power failure, UPS shall conduct discharge test regularly to keep the lead-acid battery active. The discharge test can generally be carried out once every three months. The method is to load the ups, preferably more than 50%, and then disconnect the mains power to make the ups in the lead-acid battery discharge state. The discharge duration is generally several ms to tens of MS depending on the lead-acid battery capacity. After discharge, restore the mains power supply and continue to charge the lead-acid battery.

 

Precautions affecting the use of lead-acid battery

 

Ambient temperature

Generally, the ambient temperature is about 25 ℃, and the ups floating charge voltage is set according to this temperature. In practical application, the lead-acid battery is generally charged in the range of 5 ℃ ~ 35 ℃. If it is lower than 5 ℃ or higher than 35 ℃, the capacity of the lead-acid battery will be greatly reduced and the service life of the lead-acid battery will be shortened.

 

Discharge depth

Although UPS has lead-acid battery low potential protection function, generally, when a single lead-acid battery is discharged to about 10.5V, ups will shut down automatically. However, if the UPS is under light load discharge or no-load discharge, it will also cause deep discharge of the lead-acid battery.

 

Charging current too large or too small

The discharge current is generally required to be between 0.05c ~ 3C. UPS can meet this requirement in normal use, but it is also necessary to prevent accidents, such as lead-acid battery short circuit, etc.

 

Charging voltage

Abnormal charging voltage may be caused by lead-acid battery configuration error or charger failure. Therefore, when installing batteries, we must pay attention to the correctness of the specifications and quantities of batteries, and do not mix batteries of different specifications and batches. Do not use inferior chargers for additional chargers, and consider heat dissipation during installation.

 

Do not add or reduce several single batteries in the lead-acid battery pack

This will cause the imbalance of single lead-acid battery capacity and uneven charging, and reduce the service life of the lead-acid battery.

Understanding and clarifying the important factors affecting the service life of lead-acid battery and the matters needing attention in the use process is very helpful for us to correctly use and maintain lead-acid  battery in UPS system. I hope you can correctly use and maintain lead-acid batteries in your daily work so that they can be used more reasonably.

Factors affecting and restricting the low-temperature performance of lithium ion battery

Factors affecting and restricting the low-temperature performance of lithium ion battery

Since entering the market, lithium-ion battery has been widely used because of its long service life, large specific capacity and no memory effect. There are some problems in the low-temperature use of lithium-ion batteries, such as low capacity, serious attenuation, poor cycle rate performance and so on.

It is reported that the discharge capacity of lithium-ion battery at – 20 ℃ is only about 31.5% of that at room temperature. The working temperature of traditional lithium ion battery is – 20 – + 55 ℃. However, in aerospace, electric vehicles and other fields, the battery is required to work normally at – 40 ℃. Therefore, it is of great significance to improve the low-temperature properties of lithium-ion batteries.

Factors restricting the low temperature performance of lithium ion batteries

 

The viscosity of electrolyte increases

At low temperature, the electrolyte partially solidifies, resulting in the decrease of conductivity of lithium-ion battery. The compatibility between electrolyte, negative electrode and diaphragm becomes poor.

The negative electrode of lithium ion battery precipitates lithium seriously

The precipitated metal lithium reacts with the electrolyte, and the product deposition leads to the increase of the interface thickness of the solid electrolyte.

Reduction of internal diffusion system of active substances

At low temperature, the charge transfer impedance of lithium-ion battery increases significantly.

 

Factors affecting low temperature performance of lithium ion battery

 

Electrolyte

Electrolyte has the greatest influence on the low temperature performance of lithium ion battery. The composition and physicochemical properties of electrolyte have an important impact on the low temperature performance of battery. The problem of battery cycling at low temperature is that the electrolyte viscosity will increase and the ion conduction velocity will slow down. The electron migration velocity of the external circuit does not match. Therefore, the battery appears serious polarization and the charge discharge capacity decreases sharply. Especially when charging at low temperature, lithium ions are easy to form lithium dendrites on the surface of the negative electrode, resulting in battery failure.

 

How to treat lithium battery correctly in winter

 

Do not use lithium batteries at low temperatures

Temperature has a great impact on lithium batteries. The lower the temperature, the lower the activity of lithium battery, which directly reduces the charge discharge efficiency. Generally speaking, the operating temperature of lithium battery is – 20 ° C – 60 ° C.

When the temperature is lower than 0 ℃, pay attention not to charge outdoors. We can take the battery indoors for charging. When the temperature is lower than – 20 ℃, the battery will automatically enter the sleep state and cannot be used normally. Therefore, users in particularly cold places in the north, who really do not have indoor charging conditions, should make full use of the waste heat during battery discharge and charge in the sun immediately after parking, so as to increase the charging capacity and avoid lithium precipitation.

Develop the habit of filling as you use

In winter, when the battery power is too low, we should charge in time and form the good habit of charging with use. Remember, never estimate the battery power in winter according to the normal battery life. In winter, the activity of lithium battery decreases, which is very easy to cause over discharge and overcharge. At least, it will affect the service life of the battery, and at worst, it will cause combustion accidents. Therefore, pay more attention to charging in the way of shallow discharge and shallow charge in winter. In particular, do not park the vehicle for a long time by charging all the time to avoid overcharging.

Do not charge for a long time

Do not charge for a long time for convenience. Just pull it out when it is full. The charging environment in winter shall not be lower than 0 ℃. During charging, do not leave too far to prevent emergencies and deal with them in time.

When charging, use a special charger for lithium battery

The market is full of a large number of inferior chargers. The use of inferior chargers will cause battery damage and even fire. Don’t be greedy for cheap, buy low-cost and unprotected products, and don’t use lead-acid battery chargers. If your charger doesn’t work properly, stop using it immediately. Don’t lose money for small things.

Pay attention to the battery life and replace it in time

Lithium batteries have a service life, and the service life of batteries of different specifications and models is different. Coupled with improper daily use, the service life of the battery ranges from a few months to three years.

Leave enough electricity for the winter

If the battery is not used for a long time, remember to charge 50% – 80% of the power, remove it from the vehicle for storage, and charge it regularly, about once a month. Note: the battery must be stored in a dry environment.

Place the battery correctly

Do not immerse the battery in water or wet the battery.

Advantages, cycle life, influencing factors and battery recovery of lifepo4 battery

Advantages, cycle life, influencing factors and battery recovery of lifepo4 battery

Advantages of lifepo4 battery

Good safety performance

Safety comes from the stability of cathode materials and reliable safety design. lifepo4 battery pack has passed strict safety test and will not explode even in severe collision.

Long cycle life

The 1C cycle life of lifepo4 battery generally reaches 2000 times, or even more than 3500 times. The energy storage market requires more than 4000-5000 times, which is higher than other types of lithium batteries.

Good high temperature performance

The thermal peak of lifepo4 battery can reach 350 ~ 500 ℃. The working temperature range is wide, and 100% capacity can still be released under high temperature.

Fast charging

Using a special charger, the battery can be fully charged after charging at 1.5C for 40 minutes.

Green environmental protection

Lifepo4 battery is green, non-toxic, pollution-free, with a wide range of raw materials and low price.

 

Cycle life of lifepo4 battery

 

Lifepo4 battery is used at room temperature

Basically, the cycle life is more than 2000 times. Small lithium battery manufacturers with slightly inferior quality also have a cycle life of more than 1000 times.

Lifepo4 battery used in high temperature environment

At present, the high temperature performance of lifepo4 battery is not very mature, and the operating temperature is – 20 ℃ to 125 ℃. This temperature range is the theoretical value, and the actual application temperature range is smaller.

Lifepo4 battery used in low temperature environment

The effect of low temperature on the performance of lifepo4 battery is greater than that of high temperature. According to the current market situation, the service life of lifepo4 battery is significantly reduced when it works below – 20 ℃ to – 40 ℃, and the cycle service life is about 300 times.

 

Factors affecting cycle life of lifepo4 battery

 

Charge discharge

When selecting a charger, it is best to use a charger with a proper termination charging device. In order to avoid shortening the service life of lifepo4 battery due to overcharge. Generally speaking, slow charging can prolong the service life of the battery better than fast charging.

Discharge depth

The depth of discharge is the main factor affecting the service life of lifepo4 battery. The higher the depth of discharge, the shorter the life of lifepo4 battery. In other words, as long as the discharge depth is reduced, the service life of lifepo4 battery can be greatly prolonged. Therefore, we should avoid over discharging the lithium battery ups to a very low voltage.

Work environment

If lifepo4 battery is used at high temperature for a long time, its electrode activity will be attenuated and its service life will be shortened. Therefore, it is a good way to prolong the service life of lifepo4 battery to keep it at an appropriate operating temperature.

 

Recovery of lifepo4 battery

 

Fire recovery process

The traditional fire recovery method is generally to burn the electrode pieces at high temperature to burn the carbon and organic matter in the electrode fragments. The remaining ash that cannot be burned is finally screened to obtain fine powder materials containing metals and metal oxides.

Wet recovery process

Wet recovery mainly dissolves metal ions in lifepo4 battery through acid-base solution. Further, the dissolved metal ions are extracted in the form of oxides and salts by precipitation and adsorption. Reagents such as H2SO4, NaOH and H2O2 are mostly used in the reaction process.

Factors affecting the price and safety of lithium batteries

Factors affecting the price and safety of lithium batteries

Lithium battery energy storage is an inevitable trend of the development of the times. The application and development of lithium battery is very rapid. It has the advantages of high energy density, long service life, green and environmental protection.

Lithium battery is a kind of battery with lithium metal or lithium alloy as cathode material and non-aqueous electrolyte solution. Because the chemical properties of lithium metal are very active, the processing, preservation and use of lithium metal have very high requirements for the environment. Lithium battery is widely used in electric vehicle industry, especially the emergence of lithium iron phosphate battery, which promotes the development and application of lithium battery industry.

 

Price composition of lithium battery


The price of lithium battery is mainly composed of three parts: cell, protective plate and shell. At the same time, due to the power consumption and current of the electrical appliances, the material selection of the connecting piece between the electric cores will affect the cost. Different connectors may also have a great impact on the cost, and different pack processes may also affect the cost.

 

Factors affecting the price of lithium battery

 

Selection of cell

The selection of cells with different material systems will affect the price of the whole lithium battery. According to different cathode materials, lithium battery pack will have lithium manganate (3.6V), lithium cobaltate (3.7V / 3.8V), nickel cobalt lithium manganate (commonly known as ternary, 3.6V), lithium iron phosphate (3.2V), lithium titanate (2.3V / 2.4V) and other material systems. The voltage platform, safety factor, cycle times, energy density ratio and working temperature of cells with different material systems are different.
The prices of different brands of batteries will also vary greatly. The total price gradient can be divided into: the price difference of different brands of cells with the same material system will also be very large. Moreover, the quality of each brand of electric core through the survival of the fittest in the market is basically proportional to the price.

Demand and design of lithium battery PCM

PCM design can be divided into: basic protection, communication and BMS.
Basic protection: basic protection includes overcharge, over discharge, over-current and short circuit protection, and over-temperature protection can be added according to product requirements.

Communication: the communication protocol can be divided into I2C, RS485, RS232, CANbus, HDQ, SMBus, etc. there is also a simple power display, which can be indicated by power meter and led.

BMS: battery management system is mainly used to intelligently manage and maintain each battery unit, prevent overcharge and overdischarge of the battery, prolong the service life of the battery and monitor the state of the battery. Its main functions include real-time monitoring of battery physical parameters, battery state estimation, online diagnosis and early warning, charge, discharge and precharge control, balance management and thermal management.

Demand and design of lithium battery shell

Lithium battery shell design can be divided into: PVC heat seal, plastic and metal
PVC heat seal: what kind of shell packaging form is used outside the battery pack, mainly depends on the specific needs of customers. For the packaging form of PVC heat seal, it is generally applicable to the case that the number of series and parallel cells is small and the overall weight is light. However, for the battery pack with an overall weight of ≥ 1kg, it is necessary to add a fixed support between the cells, add glass fiber board on the periphery for protection, and then use PVC heat sealing.

Plastic: plastic shell is adopted, mainly after different battery packs are finalized, the shell involved may need to be opened. Mold cost is not a small expense. For example, in the early stage of development, if the product is not finalized, the hand board shell can be used for proofing. The different material and process requirements of the shell will also affect the cost.
Metal: the metal shell is the same as the plastic shell. Before the product is finalized or the quantity demand is not much. It is recommended to use sheet metal for sample preparation, which is mainly because the sample preparation delivery time is short. If the batch is large, it is also recommended to open the mold. For the metal shell with waterproof grade requirements, it will also greatly affect the cost. There are also requirements for special material metal shell, and the cost will be higher.

The cost of lithium battery is mainly composed of battery cell, PCM and structural parts. In addition, the pack cost, aging cost and management cost of the enterprise need to be added. At the same time, due to the different requirements of product technical difficulty, purchase amount and defect rate, the price of lithium battery will also vary greatly.

 

Factors affecting the safety of lithium batteries

 

1. The ambient temperature should not be too high or too low. It is best to work at normal temperature.
2. If you receive a violent impact or puncture, it will immediately cause fire.
3. Excessive discharge greatly reduces the service life of lithium battery.
4. Poor circuit insulation, water inflow, resulting in short circuit, etc.

Difference between colloidal battery and lead-acid battery

Difference between colloidal battery and lead-acid battery

Colloidal battery and lead-acid battery have the same performance. But the electrolyte in the battery is a semi solidified emulsion state and a liquid state. Liquid lead-acid batteries need to be maintained by adding distilled water irregularly during use, and colloidal batteries do not need to be maintained by adding distilled water.

Lead acid battery: the electrode is mainly made of lead and its oxide. The electrolyte is a battery of sulfuric acid solution. In the discharge state, the main component of the positive electrode is lead dioxide and the main component of the negative electrode is lead. Under the charging state, the main components of the positive and negative electrodes are lead sulfate.

 

Performance characteristics of lead-acid battery

 

Safety seal

During normal operation, the electrolyte will not leak from the terminal or housing of the battery.

No free acid

A special suction baffle keeps the acid inside. There is no free acid inside the battery, so the battery can be placed in any position.

Venting system

When the internal pressure of the battery exceeds the normal level, the VRLA battery will release excess gas and automatically reseal. Ensure that there is no excess gas in the battery.

Simple maintenance

Due to the unique gas composite system, the generated gas is converted into water. There is no need to add water during the use of the battery.

Long service life

Lead calcium alloy breast board with anti-corrosion structure is adopted, and the battery can be used for floating charge for 10-15 years.

Stable quality and high reliability

With advanced production technology and strict quality control system, the battery has stable quality and reliable performance. Voltage, capacity and sealing shall be 100% inspected on the line.

 

Application scope of lead-acid battery

 

Emergency power supply

1. Telecommunications.
2. Solar system.
3. Electronic switch system.
4. Communication equipment: base station, PBX, CATV, wll, ONU, STB, cordless telephone, etc.
5. Backup power supply: UPS, ECR, computer backup system, sequence, etc.
6. Emergency equipment: emergency light, flashlight, fire alarm, burglary alarm, fire damper.

Main power supply

1. Communication equipment: transceiver,
2. Electric control locomotive: collection vehicle, automatic transport vehicle, electric wheelchair, cleaning robot, electric vehicle, etc,
3. Mechanical tool Starters: lawn mowers, hedgetrimmers, cordless electric drills, electric drivers, electric sledges, etc,
4. Industrial equipment / instruments,
5. Camera: flash, VTR / VCR, movie light, etc,

Colloidal battery is an improvement of ordinary lead-acid battery with liquid electrolyte. Colloidal electrolyte is used to replace sulfuric acid electrolyte. Compared with ordinary batteries, it has improved in safety, power storage, discharge performance and service life.

 

Working principle of colloidal battery

 

The performance of colloidal lead-acid battery is better than that of valve regulated lead-acid battery. Colloidal lead-acid battery has stable performance and high reliability. Long service life, strong adaptability to ambient temperature, long-time discharge capacity, cyclic discharge capacity, strong deep discharge and high current discharge capacity, and has the advantages of overcharge and over discharge self-protection.

Colloidal lead-acid batteries began to crack and shrink after being used for a period of time. Cracks are generated, and oxygen is directly sent to the negative plate through the cracks for oxygen circulation. The exhaust valve is no longer often opened, and the colloidal lead-acid battery is close to sealing, with little water loss. Therefore, for the electric bicycle battery, the main failure is the water loss mechanism, and the colloidal battery can achieve very good results. Colloidal electrolyte is made by adding gel into the electrolyte to solidify the sulfuric acid electrolyte into a colloidal substance. Generally, colloidal stabilizer and compatibilizer are added to colloidal electrolyte, and retarding colloidal solidification and retarding agent are added to some colloidal formulas to facilitate colloidal filling.

 

Performance characteristics of colloidal battery

Preparation of high quality colloid with fumed silica

The electrolyte is evenly distributed and there is no acid stratification.

The electrolyte is gel fixed.

No flow, no liquid leakage and uniform reaction of all parts of the electrode plate.

Tight fitting technology is adopted

Excellent high rate discharge performance.

Excess electrolyte

The battery has large thermal capacity, strong heat dissipation capacity and wide working temperature range.

All high-purity raw materials are used

The self discharge electrode of the battery is small.

Using gas recombination technology

The battery has high sealing reaction efficiency, no acid mist precipitation, safety, environmental protection and no pollution.

Adopt special design

Reliable sealing technology ensures that the battery is sealed and safe and reliable.

 

Application scope of colloidal battery

 

1. Communication system: switch, microwave station, mobile base station, data center, radio and broadcasting station.
2. Power plant and power transmission and transformation system;
3. Solar and wind power systems
4. Signal system and emergency lighting system
5. EPS and UPS system