What are the reasons for the bulging of lithium iron phosphate battery packs and batteries?

The reason for the bulging of lithium iron phosphate battery: 1. Overcharge of the lithium battery caused by overcharging will cause all the lithium atoms in the positive electrode material to run into the negative electrode material, causing the original full grid of the positive electrode to deform and collapse. This is also a lithium iron phosphate battery An important reason for the decrease in group power. In this process, there are more and more lithium ions in the negative electrode, and the excessive accumulation makes the lithium atoms grow out of the tree stump crystals, which makes the lithium battery pack swell. 2. Bulging caused by over-discharge During the first charge and discharge of a liquid lithium battery, the electrode material and the electrolyte react at the solid-liquid interface to form a passivation layer covering the surface of the electrode material. The formed passivation film can effectively prevent the passage of electrolyte molecules, but Li+ can be freely inserted and extracted through the passivation layer, which has the characteristics of a solid electrolyte, so this passivation film is called SEI. The SEI film is not static, there will be a little change during the charge and discharge process, the important thing is that some organic matter will undergo reversible changes. The over-discharge of the lithium iron phosphate battery causes the SEI film to be reversibly broken, and the destruction of the SEI protecting the negative electrode material causes the negative electrode material to collapse, thereby forming a bulging phenomenon. 3. The problem of manufacturing level Lithium battery bulge may be a problem of the manufacturing level of lithium iron phosphate battery pack, the electrode coating is not uniform, and the processing technology is relatively rough. Four. The bulging phenomenon of the lithium iron phosphate battery pack will also occur if it is not used for a long time, because the air is conductive to a certain extent, so if the battery is left for too long, it is equivalent to the direct contact of the positive and negative electrodes of the battery and a chronic short circuit . How to deal with the bulging of iron-lithium battery? 1. Please do not continue to use the bulging battery, if bulging occurs, try to replace the new lithium battery pack in time. Try not to rely on some methods taught online to continue using the battery. 2. In normal times, don't charge while playing with your mobile phone. Regularly adhere to the battery condition to avoid dangerous situations. 3. In normal times, when charging, pay attention to the choice of charger. For example, the rated charging voltage of the battery is 3.7V, and the limit voltage is 4.2V. Try not to choose a charger that exceeds this voltage. It is best to maintain a constant current. 4. Choose lithium iron phosphate battery packs processed by large manufacturers, so the quality is relatively reliable. It is important that you should pay more attention to the damage to the battery caused by your usual usage habits. 5. If the mobile phone battery has been charged up, use your fingers to find the gap in the battery (the back of the mobile phone battery is close to the charging electrode of the mobile phone, press down to a soft place), and poke a small hole with the pointer to make the inside Just run out of air. 6. If you have multiple lithium iron phosphate battery packs that are swollen, it should be that the cut-off voltage of the charger you are using does not match the battery, and it is recommended to replace it. Reasons for battery bulge: 1. Safety valve pressure is too high. Valve-regulated lead-acid batteries are equipped with a row of safety valves to ensure safe use. When the pressure in the battery rises, the safety valve will automatically open to release the pressure. Ensure that the air pressure inside and outside the battery is balanced. And if the safety valve cannot be opened normally when the pressure in the battery rises, over time, due to the high pressure in the battery and the imbalance of the internal and external air pressure, bulging will occur. 2. Overcharge and overdischarge Battery engineers have repeatedly emphasized that the battery should try to prevent overcharge and overdischarge. Overcharge and overdischarge will cause poor gas recombination in the battery, and a violent reaction similar to a short circuit will occur inside the battery, resulting in a large amount of heat, which will lead to electrolyte Decompose and vaporize, and the battery swells up. 3. The charging current is too large. Normally, according to the battery instruction manual, the charging current of the battery BT-HSE12V battery should not exceed 0.25C. Normal use is recommended to be 0.1C (10A), and the charging current is greater than this reasonable current value during charging, it is easy As a result, the precipitation on the electrode plate is too fast, which in turn leads to insufficient chemical reaction. At this time, the temperature inside the battery will rise rapidly, and the battery will bulge if the exhaust is not timely. 4. The float charge voltage is set too high. The float charge voltage of the battery is set too high and the charging current is large, which causes the precipitation of O2 on the positive plate to accelerate, and it is too late to recombine in the negative electrode. At the same time, the temperature in the battery rises quickly, and the exhaust is too late. , When the pressure reaches a button, the VRLA battery will be bulged and deformed. Reasons for the bulging of lithium batteries for electric vehicles: 1. The quality of the charger is inferior. The current price warfare, the quality of the charger has been declining. The use of inferior materials, refurbished or inferior components, heat generation, inaccurate parameter drift, makes the charging voltage limit out of control, resulting in lithium The squeezing of the gas inside the battery pack causes the battery shell to deform, crack, or even explode. 2. The charging time is too long. Some users don’t have the concept of time when charging. They think that they will stop when they are fully charged. Some even charge for two days and two nights. Only after using it, they think about it. After charging for a long time, lithium batteries for electric vehicles. The battery life will be threatened. If overcharging will cause a large amount of gas to wash the plates, cause the active material inside the battery to fall off, shorten the battery life, make the battery lose water faster, affect the decomposition of the electrolyte, increase the battery temperature, and make it charge. drum! 3. Internal failure of the battery The internal battery plate group has quality problems, micro short circuit, lack of acid leakage, lack of water, causing thermal runaway, increasing the internal pressure of the lithium battery, the safety valve can not release the pressure, and the exhaust valve hole is blocked. The increase of internal gas pressure causes deformation of the battery shell, cracking and swelling. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to maintain large-capacity lithium battery packs at low temperatures