Safety of lithium-ion batteries

1、 Pay attention to short circuit Please pay attention to the safety of lithium-ion batteries. Lithium ion batteries are prone to short circuit during charging. Although most lithium-ion batteries now have short-circuit protection circuits and explosion-proof wires. But in many cases, this circuit may not work under various circumstances. Explosion-proof wire can also play a limited role. 2、 Do not overcharge All lithium-ion batteries, whether developed in the past or polymer lithium-ion batteries and lithium-iron batteries developed in recent years, are very afraid of overcharging. If the charging time of lithium-ion battery is too long, the possibility of explosion will increase. Lithium has very active chemical properties and is easy to burn. When the battery is charged and discharged, the internal temperature of the battery continues to rise, and the gas generated in the activation process expands, which increases the internal pressure of the battery. When the pressure reaches a certain level, if the shell is scarred, it will break, causing liquid leakage, fire and even explosion. Therefore, you should pay great attention to safety when using lithium-ion batteries.

Nine advantages of lithium battery

The nine advantages of lithium battery are as follows: 1. The energy is relatively high. It has a high storage energy density, which has reached 460-600Wh, about 6-7 times that of lead-acid batteries; 2. The service life is long, and the service life can reach more than 6 years. The battery with lithium ferrous phosphate as the positive electrode 1C (100% DOD) can be charged and discharged with a record of 10000 times; 3. The rated voltage is high (the single working voltage is 3.7V or 3.2V), which is about equal to the series voltage of three nickel-cadmium or nickel-hydrogen batteries, which is convenient to form the battery power pack; 4. It has high power bearing capacity, among which the lithium ferrous phosphate lithium ion battery for electric vehicles can reach the capacity of 15-30C charging and discharging, which is convenient for high-intensity starting acceleration; 5. The self-discharge rate is very low, which is one of the most prominent advantages of the battery. At present, it can generally achieve less than 1%/month, less than 1/20 of the nickel hydrogen battery; 6. Light weight, about 1/5-6 of lead acid product in the same volume; 7. High and low temperature adaptability, can be used at - 20 ℃ - 60 ℃, and can be used at - 45 ℃ after process treatment; 8. Green environmental protection, no matter how it is produced, used or scrapped, it does not contain or produce any toxic and harmful heavy metal elements and substances such as lead, mercury and cadmium. 9. Production basically does not consume water, which is very beneficial to China, which is short of water. Specific energy refers to the energy per unit weight or volume. Specific energy is expressed in Wh or Wh/L. Wh is the unit of energy, W is the watt and h is the hour; Kg is the kilogram (weight unit) and L is the liter (volume unit).

Positive and negative pole composition of lithium battery

Lithium batteries usually have two types of appearance: cylindrical and square. The inside of the battery is spiral wound structure, which is made of a very fine and highly permeable polyethylene film isolation material between the positive and negative electrodes. The positive electrode includes a current collector composed of lithium cobaltate (or nickel cobalt lithium manganate, lithium manganate, lithium ferrous phosphate, etc.) and aluminum foil. The negative electrode is composed of a current collector composed of graphitized carbon material and copper foil. The battery is filled with organic electrolyte solution. In addition, there are safety valves and PTC elements (some cylindrical elements are used) to protect the battery from damage in case of abnormal state and output short circuit. The voltage of a single lithium battery is 3.7V (3.2V for lithium ferrous phosphate anode), and the battery capacity cannot be unlimited. Therefore, a single lithium battery is often processed in series and parallel to meet the requirements of different occasions.

Main characteristics of lithium ion battery

A. The weight of high energy density lithium ion battery is half of that of nickel cadmium or nickel hydrogen battery with the same capacity, and the volume is 20-30% of nickel cadmium and 35-50% of nickel hydrogen. B. High voltage The working voltage of a single lithium-ion battery is 3.7V (average), which is equivalent to three nickel-cadmium or nickel-hydrogen batteries in series. C. Non-polluting lithium-ion batteries do not contain harmful metal substances such as cadmium, lead and mercury. D. The lithium-ion battery without metal lithium does not contain metal lithium, so it is not subject to the provisions of aircraft transportation on the prohibition of carrying lithium batteries in passenger aircraft. E. High cycle life Under normal conditions, the charge and discharge cycle of lithium ion battery can exceed 500 times, and the lithium ferrous phosphate (hereinafter referred to as ferrophosphate) can reach 1000 times. F. Memory effect without memory effect refers to the phenomenon that the capacity of Ni-Cd battery decreases during the charge-discharge cycle. Lithium ion batteries do not have this effect. G. The constant current and constant voltage charger with rated voltage of 4.2V is used for fast charging, which can make the lithium ion battery fully charged within 1.5-2.5 hours; The newly developed lithium phosphate battery can be fully charged in 35 minutes.

Long-term storage method of disposable lithium battery and rechargeable lithium battery

As lithium batteries are more and more widely used in our lives, how much do you know about the long-term storage methods of disposable lithium batteries and rechargeable lithium batteries? Let whirlpool battery briefly introduce you! 1. Lithium primary battery Also called primary lithium battery. It can discharge continuously or intermittently. Once the power is exhausted, it can not be used again. It is widely used in cameras and other electronic products with low power consumption. The lithium primary battery has low self-discharge and can be stored for 3 years. The effect will be better if it is stored in cold storage. It is a good way to store the lithium primary battery in a low temperature place. Note: Unlike lithium-ion batteries, lithium-ion batteries cannot be recharged. Charging is very dangerous! 2. Lithium ion battery is also called secondary lithium battery. It can be stored for more than half a year at 20 ℃ because of its low self-discharge rate and most of its capacity can be recovered. There is self-discharge phenomenon in lithium batteries. If the battery voltage is kept below 3.6V for a long time, it will lead to battery over-discharge, damage the internal structure of the battery and reduce the battery life. Therefore, lithium batteries stored for a long time should be recharged every 3~6 months, that is, charged to a voltage of 3.8~3.9V (the best storage voltage of lithium batteries is about 3.85V), kept at a discharge depth of 40% - 60%, and should not be fully charged. The battery shall be stored in a dry environment of 4 ℃~35 ℃ or in a moisture-proof package. Keep away from heat sources, and do not place it in direct sunlight. Lithium battery has a wide range of application temperatures. It can still be used outdoors in winter in the north, but its capacity will be much lower. If it returns to room temperature, its capacity can be restored.

Do you know the regulations on carrying lithium batteries in aircraft?

With the pace of people's life getting faster and faster, lithium batteries are widely used in our daily life today. Do you know the rules of carrying lithium batteries by plane? In order to ensure flight safety and avoid unsafe events caused by passengers carrying lithium batteries (lithium metal batteries are easy to ignite when the temperature inside the aircraft is high), in August 2008, the Civil Aviation Administration of China made clear provisions for passengers carrying lithium batteries on board: First, passengers are not allowed to carry lithium batteries in checked baggage. Second, passengers can carry lithium-ion battery cells or consumer electronic devices (watches, calculators, cameras, mobile phones, laptops, camcorders, etc.) for personal use. The backup battery must be individually protected against short circuit and can only be carried in hand luggage. In addition, each spare battery shall not exceed the following quantities: for lithium metal or lithium alloy batteries, the lithium content shall not exceed 2 grams; For lithium-ion batteries, the total lithium content of the same mass shall not exceed 8 grams. Third, passengers can carry lithium-ion batteries with a total lithium content of more than 8g but not more than 25g. If a single battery can be protected from short circuit, it can be carried in hand luggage. Spare batteries are limited to 2 per person. Fourth, other types of standby dry batteries, such as nickel-metal hydride batteries, can also be carried with you if short circuit protection measures are taken. Fifthly, lithium-ion batteries with total lithium content of more than 25 grams of equivalent quality shall be shipped in the form of goods in accordance with the standard of the Specification for Air Transport of Lithium Batteries (MH/T1020-2007).