Lithium battery research and development of solar street lamps

; Lithium batteries; , is a kind of lithium metal or lithium alloy anode materials, the use of water electrolyte solution of the battery. Due to the lithium chemistry is very lively, making lithium metal processing, storage, use, very high demand on the environment. So, lithium battery long

; Lithium batteries; Is a use lithium metal or lithium alloy as the cathode material and nonaqueous electrolyte solution of the battery. Due to the chemical properties of lithium is very active, lithium metal processing, preservation and use has a high requirement to the environment. As a result, the lithium battery has a very long time no use. With the development of science and technology, the lithium battery has become the mainstream. Overcharge protection

lithium battery core to above 4. 2 v voltage, side effects will start to appear. Excessive charging pressure, the greater the risk is higher. In lithium core voltage is higher than 4. After 2 v, the rest of the anode material of lithium atom the number of less than half. At this point, the battery will collapse, often lead to battery capacity permanent decline. If continue to recharge, then the lithium metal will accumulate on the surface of the negative electrode materials, because of the negative electrode of the battery is full of lithium atom. The lithium atoms from the cathode surface to lithium ion direction dendrite growth. The lithium metal crystal will through the diaphragm paper, make the positive and negative electrode short circuit. Sometimes in short circuit batteries before the explosion. This is because in the process of charging, electrolyte materials such as gas burst, causing the battery shell or pressure valve inflation and burst, and accumulated in oxygen into the lithium atoms on the surface of the cathode reaction, to explode. Therefore, when for lithium battery, you must set up the voltage limit, so that you can consider the battery life, capacity and security. The most ideal charging voltage limit is 4. 2 v。 。 Lithium battery discharge should also have a lower voltage limit. When the battery voltage is lower than 2. 4 v, some material will begin to be destroyed. Because the battery will discharge themselves, the longer the discharge time, the lower voltage. Therefore, discharge when had better not stop in 2. 4V。 From 3. Discharge to 2 0 v. 4 v during discharge, the release of energy accounted for only about 3% of battery capacity. Therefore, 3. 0 v is the ideal discharge cut-off voltage. Charging and discharging, in addition to the voltage limit and current limit is necessary. When the current is too large, lithium ion can't get into the battery, and will accumulate on the surface material. These acquired electronic lithium ion, lithium atom crystal will be generated in the material surface, it's like overcharge, can cause dangerous. If the battery box is broken, and it will explode. Therefore, lithium ion battery protection shall include at least three: charging voltage upper limit and lower limit discharge voltage and current limit. In general, in addition to the lithium battery core in lithium battery pack, there is a protection board, mainly provide three kinds of protection. These three, however, the protection of the protection board is obviously not enough, the lithium battery explosion still frequently around the world. In order to ensure the safety of the battery system, must be more carefully analyse the causes of battery explosion. The explosion reason

1. Large internal polarization; 2, pole piece suction and reaction with electrolyte formed gas reservoir; 3. The quality and performance of the electrolyte itself; 4. Injection liquid, the injection of the liquid quantity can not meet the requirement of the process; 5. Laser welding of poor sealing performance in the assembly process, detect the leakage in the process of gas leakage. 6, dust, dust sheet first cause micro short circuit; 7. Positive plate and negative plate thicker than the range of technology, hard into the shell. 8. Liquid injection and sealing problem is ball sealed performance is poor, leading to the pump. 9. Due to the incoming material shell, shell wall thickness is too thick, the thickness of shell deformation effect; 10, the environment temperature is the main reason for the explosion.