Keyword search: battery plant ,  lithium battery factory ,  power bank works ,  lifepo4 battery mill ,  Pallet Trucks LiFePO4 Battery,  LiFePO4 Pallet Trucks Battery,  Lithium Pallet Trucks Battery, 

The IEC standard cycle life test for lithium batteries is:

After discharging the battery at 0.2C to 3.0V/

Charge at 1.1C constant current and constant voltage to 4.2V with a cut-off current of 20mA, let it sit for 1 hour, and then discharge at 0.2C to 3.0V (one cycle)

After 500 cycles, the capacity should be at least 60% of the initial capacity

The national standard stipulates that the standard charge retention test for lithium batteries is (IEC has no relevant standards)

After discharging the battery at 0.2C to 3.0/unit at 25 degrees Celsius, it was charged at a constant current and voltage of 1C to 4.2V with a cut-off current of 10mA. The battery was stored at a temperature of 20+5 for 28 days and then discharged at 0.2C to 2.75V to calculate the discharge capacity

What is the self discharge rate of secondary batteries for different types of batteries?

Self discharge, also known as charge retention capability, refers to the ability of a battery to retain the stored electricity under certain environmental conditions in an open circuit state. Generally speaking, self discharge is mainly influenced by manufacturing processes, materials, and storage conditions. Self discharge is one of the main parameters for measuring battery performance. Generally speaking, the lower the storage temperature of a battery, the lower its self discharge rate. However, it should also be noted that temperatures that are too low or too high may cause battery damage and render it unusable. BYD's standard battery storage temperature range is -20~45. After the battery is fully charged and left in an open circuit for a period of time, a certain degree of self discharge is a normal phenomenon. The IEC standard stipulates that after fully charged nickel cadmium and nickel hydrogen batteries are placed in an open circuit for 28 days at a temperature of 20 degrees Celsius and a humidity of 65%, with a discharge time of 0.2C greater than 3 hours and 3 hours and 15 minutes respectively, they meet the standard.

Compared with other rechargeable battery systems, the self discharge rate of solar cells containing liquid electrolyte is significantly lower, about 10%/month at 25.

What is the internal resistance of a battery and how is it measured?

The internal resistance of a battery refers to the resistance experienced by the current flowing through the battery during operation. It is generally divided into AC internal resistance and DC internal resistance. Due to the small internal resistance of rechargeable batteries, polarization internal resistance is generated when measuring DC internal resistance due to electrode capacity polarization, making it impossible to measure its true value. However, measuring its AC internal resistance can eliminate the influence of polarization internal resistance and obtain the true internal value

The method for measuring internal resistance in communication is to use the characteristic of the battery being equivalent to an active resistor, give the battery a constant current of 1000HZ and 50mA, and perform a series of processing such as voltage sampling, rectification, and filtering to accurately measure its resistance value

What is the internal pressure of a battery? What is the normal internal pressure of a battery?

The internal pressure of a battery is formed by the gas generated during the charging and discharging process. It is mainly affected by factors such as the manufacturing process and structure of the battery material. Generally, the internal pressure of a battery is maintained at a normal level. In the case of overcharging or overdischarging, the internal pressure of the battery may increase:

If the speed of the composite reaction is lower than that of the decomposition reaction, the gas produced cannot be consumed in time, which will cause an increase in the internal pressure of the battery

What is internal pressure testing?

The internal pressure test of lithium batteries is: (UL standard)

Simulate the battery to check for leakage or bulging at an altitude of 15240m (low pressure of 11.6kPa)

Specific steps: Charge the battery 1C with constant current and voltage to 4.2V, with a cut-off current of 10mA. Then store it in a low-voltage box with a pressure of 11.6Kpa and a temperature of (20+3) for 6 hours. The battery will not explode, catch fire, crack, or leak

What is the impact of ambient temperature on battery performance?

Among all environmental factors, temperature has the greatest impact on the charging and discharging performance of batteries. The electrochemical reactions at the electrode/electrolyte interface are related to the environmental temperature, and the electrode/electrolyte interface is considered the heart of the battery. If the temperature decreases, the reaction rate of the electrode also decreases. Assuming the battery voltage remains constant and the discharge current decreases, the power output of the battery will also decrease. If the temperature rises, the opposite is true, that is, the output power of the battery will increase, and the temperature will also affect the transmission speed of the electrolyte. If the temperature rises, it will accelerate, but if the transmission temperature drops, it will slow down, and the charging and discharging performance of the battery will also be affected. But if the temperature is too high, exceeding 45 degrees, it will disrupt the chemical balance inside the battery and cause side reactions

What are the control methods for overcharging?

In order to prevent overcharging of the battery, it is necessary to control the charging endpoint. When the battery is fully charged, there will be some special information that can be used to determine whether the charging has reached the endpoint. There are generally six methods to prevent batteries from being overcharged:

1. Peak voltage control: Determine the end point of charging by detecting the peak voltage of the battery;

2. dT/dt control: Determine the end point of charging by detecting the rate of change in the peak temperature of the battery;

3. T control: When the battery is fully charged, the temperature difference between the battery and the ambient temperature will reach its maximum;

4. - V control: When the battery is fully charged and reaches a peak voltage, the voltage will drop by a certain value

5. Timing control: Control the charging endpoint by setting a certain charging time, usually by setting the time required to charge to 130% of the nominal capacity;

6. TCO control: Considering the safety and characteristics of the battery, high temperature charging should be avoided (except for high-temperature batteries), so charging should be stopped when the battery temperature rises by 60 degrees.

What is overcharging and how does it affect battery performance?

Overcharging refers to the behavior of a battery being fully charged after a certain charging process before continuing to charge.

Due to the higher capacity of the negative electrode compared to the positive electrode during design, the gas generated by the positive electrode passes through the separator paper and combines with the cadmium generated by the negative electrode. Therefore, in general, the internal pressure of the battery will not increase significantly. However, if the charging current is too high or the charging time is too long, the generated oxygen cannot be consumed in time, which may cause adverse phenomena such as internal pressure increase, battery deformation, leakage, etc. Meanwhile, its electrical performance will also significantly decrease.

What is over discharge and how does it affect battery performance?

After discharging the stored power inside the battery, if the voltage reaches a certain value, continuing to discharge will cause overdischarge. The discharge cut-off voltage is usually determined based on the discharge current. The discharge of 0.2C-2C is generally set at 1.0V/unit, while the discharge of 3C or above, such as 5C or 10C, is set at 0.8V/unit. Overdischarge of the battery may have catastrophic consequences, especially for high current or repeated overdischarging, which has a greater impact on the battery. Generally speaking, overdischarging can increase the internal pressure of the battery, damage the reversibility of the positive and negative active materials, and even if charged, only partial recovery can be achieved, resulting in a significant decrease in capacity.

What problems will occur when batteries of different capacities are used together?

If different capacities or old and new batteries are mixed together for use, there may be phenomena such as leakage and zero voltage. This is due to the difference in capacity during the charging process, which causes some batteries to be overcharged while others are not fully charged. When discharging, some batteries with higher capacity are not fully discharged, while those with lower capacity are overdischarged. This vicious cycle results in battery damage leading to leakage or low (zero) voltage.

What is a battery explosion and how to prevent it? Any solid substance in any part of the battery that is instantly discharged and pushed to a distance of more than 25cm from the battery is called an explosion. To determine whether the battery has exploded or not, conduct the following experimental conditions. Cover the experimental battery with a net, with the battery positioned in the center and 25cm away from either side of the net cover. The density of the net is 6-7 wires/cm, and the network cable uses soft aluminum wire with a diameter of 0.25mm. If there is no solid part passing through the net cover in the experiment, it proves that the battery did not explode.

The problem of lithium battery series connection

Due to the numerous processes involved in the production of batteries, from coating to becoming finished products. Even after strict testing procedures to ensure that the voltage, resistance, and capacity of each power supply are consistent, differences in one way or another can still occur after a period of use. Just like twins born to a mother, they may look exactly the same when they were born. As mothers, it is difficult to distinguish them. However, as the two children continue to grow, various differences will arise, and the same goes for lithium power batteries. After a period of use, it is difficult to apply the overall voltage control method to lithium power batteries. For example, a 36V battery stack must be connected in series with 10 batteries. The overall charging control voltage is 42V, while the discharging control voltage is 26V. By using the overall voltage control method, there may not be any issues during the initial use phase due to the excellent consistency of the battery. After a period of use, the internal resistance and voltage of the battery fluctuate, forming an inconsistent state (inconsistency is absolute, consistency is relative). Using overall voltage control at this time cannot achieve its purpose. For example, when 10 batteries are discharged, the voltage of two batteries is 2.8V, the voltage of four batteries is 3.2V, and the voltage of four batteries is only 3.4V. The overall voltage now is 32V, and we let it continue to discharge and work until 26V. In this way, the two 2.8V batteries are in an over discharge state below 2.6V. A few over discharges of a lithium battery are equivalent to being scrapped. On the contrary, charging by controlling the overall voltage can also result in overcharging. For example, charging with the voltage state of the 10 batteries mentioned above at that time. When the overall voltage reaches 42V, the two 2.8V batteries are in a "hungry" state and quickly absorb electricity, exceeding 4.2V. Overcharged batteries exceeding 4.2V not only result in scrap due to high voltage, but also pose a danger. This is the characteristic of lithium power batteries.

The rated voltage of lithium-ion batteries is 3.6V (some products have 3.7V). The termination charging voltage when fully charged is related to the anode material of the battery: 4.2V for graphite anode material; The anode material is 4.1V of coke. The internal resistance of different anode materials is also different. The internal resistance of coke anode is slightly higher, and its discharge curve is also slightly different, as shown in Figure 1. It is generally referred to as 4.1V lithium-ion battery and 4.2V lithium-ion battery. Most of the batteries currently in use are 4.2V, and the termination discharge voltage of lithium-ion batteries is between 2.5V and 2.75V (the battery factory provides the operating voltage range or termination discharge voltage, with slight differences in various parameters). Continuing to discharge below the termination discharge voltage is called overdischarging, which can damage the battery.

Portable electronic products use batteries as their power source. With the rapid development of portable products, the usage of various batteries has increased significantly, and many new types of batteries have been developed. In addition to the well-known high-performance alkaline batteries, rechargeable nickel cadmium batteries, and nickel hydrogen batteries, there are also lithium batteries developed in recent years. This article mainly introduces the basic knowledge about lithium batteries. This includes its characteristics, main parameters, significance of the model, scope of application, and precautions for use.

Lithium is a metallic element with the chemical symbol Li (its English name is lithium). It is a silver white, very soft, and chemically active metal, and is the lightest among metals. In addition to being used in the atomic energy industry, it can also manufacture special alloys, special glass (fluorescent screen glass used in televisions), and lithium batteries. It is used as the anode in lithium batteries.

Lithium batteries are also divided into two categories: non rechargeable and rechargeable. Non rechargeable batteries are called disposable batteries, which can only convert chemical energy into electrical energy at once and cannot restore electrical energy back to chemical energy (or have extremely poor reduction performance). Rechargeable batteries are called secondary batteries (also known as rechargeable batteries). It can convert electrical energy into chemical energy for storage, and then convert chemical energy into electrical energy when in use. It is reversible, as is the main characteristic of lithium-ion batteries.

Agile portable electronic products require small size and light weight, but the size and weight of the battery are often the largest and heaviest compared to other electronic components. For example, in the past, the "big brother" was quite "bulky and cumbersome", while today's mobile phones are so lightweight. The improvement of batteries has played an important role: in the past it was nickel cadmium batteries, now it is lithium-ion batteries.

The biggest feature of lithium batteries is their high specific energy. What is more than energy? Specific energy refers to the energy per unit weight or unit volume. Specific energy is expressed in Wh/kg or Wh/L. Wh is the unit of energy, W is watts, and h is hours; Kg is kilogram (weight unit), L is liter (volume unit). Here is an example to illustrate: if the rated voltage of nickel cadmium battery No. 5 is 12V and its capacity is 800mAh, then its energy is 096Wh (12V × 08Ah). The rated voltage of a No. 5 lithium manganese dioxide battery of the same size is 3V, and its capacity is 1200mAh, resulting in an energy of 36Wh. The volume of these two batteries is the same, so the specific energy of lithium manganese dioxide batteries is 375 times that of nickel cadmium batteries!

A No. 5 nickel cadmium battery weighs about 23g, while a No. 5 lithium manganese dioxide battery weighs about 18g. One lithium manganese dioxide battery is 3V, while two nickel cadmium batteries are only 24V. So when using lithium batteries, the number of batteries is small (reducing the volume and weight of portable electronic products), and the working life of the batteries is long.

In addition, lithium batteries have the advantages of stable discharge voltage, wide operating temperature range, low self discharge rate, long storage life, no memory effect, and no pollution.

Lithium Batteries ,Ensure Quality

Our lithium battery production line has a complete and scientific quality management system

Ensure the product quality of lithium batteries

Years of experience in producing lithium batteries

Focus on the production of lithium batteries

WE PROMISE TO MAKE EVERY LITHIUM BATTERY WELL

We have a comprehensive explanation of lithium batteries

QUALIFICATION CERTIFICATE

THE QUALITY OF COMPLIANCE PROVIDES GUARANTEE FOR CUSTOMERS

MULTIPLE QUALIFICATION CERTIFICATES TO ENSURE STABLE PRODUCT QUALITY

Providing customers with professional and assured products is the guarantee of our continuous progress.

Applicable brands of our products