What are the safety measures for lithium batteries for electric vehicles

1. Safety measure 1: Software BMS protection board, remote security monitoring. Nowadays, the domestic battery cell manufacturing level does not reach the consistency accuracy of Japan and South Korea. The battery itself has certain security risks. If only a pure hardware BMS board is used for protection, There is a probability of failure of such electronic components, and once the BMS fails, a safety accident will inevitably occur. Luyuan’s solution is to add a remote data transmission module to realize the data interconnection of key electrical components of the vehicle, including the charging and discharging data of the lithium battery. Through the data monitoring platform of the headquarters, we can predict battery failure modes, inform users in advance and provide quick services, and eliminate potential safety hazards in the bud. 2. Safety measures 2: Improve the structure and enhance the safety of lithium batteries Compared with electric bicycles, the use environment of lithium batteries for electric bicycles is more severe. The vehicle's shock absorption performance is poor; the riding conditions are complicated; the vehicle is often placed outdoors, and the battery is exposed directly to the outside, experiencing wind, sun, and rain. Lvyuan independently designed a fully sealed, breathable, dry, water-proof and moisture-proof structure. The interior is filled with high thermal conductivity silica gel. While improving the seismic level of the internal battery core and BMS board, it also further enhances the waterproof and moisture-proof performance. At the same time, it achieves the purpose of equalizing the temperature between the cells inside the battery, ensuring the consistency of the cells, and thereby improving the service life of the entire battery. 3. Safety measure 3: Two-way handshake recognition circuit to ensure that the battery is not used indiscriminately. Electric bicycles on the market are basically straight-through output methods, which facilitates the abuse of battery supply by users. If the lithium battery is used in lead-acid vehicles, that is, lead-to-lithium sales; or used as a test treasure for lead-acid vehicle trial riding; there will also be maintenance personnel using lead-acid controllers or chargers to replace faulty lithium battery control And charger. These are the bad habits left by the lead-acid battery era. Once the lithium battery is misused on a lead-acid vehicle, the lead-acid controller has EABS reverse charging and is inconsistent with the undervoltage point of the lithium battery, which will cause safety hazards to the lithium battery. Luyuan’s countermeasure is to add a two-way handshake recognition circuit between the lithium battery BMS board and the controller, and before the BMS board and the charger. As long as they do not match each other, the lithium battery will close the charging and discharging circuit, and illegal control is not allowed. Discharging the charger and charging illegal chargers to reduce safety accidents of lithium batteries caused by external factors. 4. Lithium battery safety measures 4: PGR motor guards against lithium battery reverse charging, EABS reverse charging, which is a very good point of interest for lead-acid batteries, but for lithium batteries, it has become a safety hazard. What are the hazards of reverse charging of lithium batteries? We have already analyzed the charging principle of lithium batteries, that is, lithium ions are extracted from the positive electrode and migrate to the porous graphite negative electrode through the diaphragm and electrolyte. If the lithium ion migration speed is not fast enough and the migration amount is too large, it will stay on the surface of the negative electrode to form metallic lithium dendrites, which will pierce the diaphragm to a certain extent and cause a short circuit explosion. The factors that affect the number and speed of lithium ion migration during the charging process are the environmental temperature and the charging current. Although the EABS function has been cancelled for lithium electric vehicles, reverse charging current will still occur during downhill sliding: the existing industry lithium electric bicycles generally use low-speed hub direct-drive motors, which are electric motors during riding, but downhill. When the slope slides at high speed, it becomes a generator. When the motor speed exceeds the rated speed, the back-EMF voltage will be higher than the battery voltage, and the energy will be injected back into the battery. The faster the vehicle drops, the higher the induced back-EMF, that is, the greater the back-charge current. Especially in the case of the new national standard electric bicycle with a maximum speed of 25 kilometers per hour, the glide speed on a downhill section will easily exceed the maximum speed of 25 kilometers per hour, and the reverse charging current is extremely large, especially in the cold winter, the electrolyte conducts electricity The rate of lithium ion migration decreases, and the probability of metallic lithium dendrite formation on the surface of the negative electrode is greater. Diaphragm piercing is more likely to occur. In the slightest, the battery capacity will drop sharply, the life will decline faster, and the large-area short circuit heating will occur , And eventually burned out of control and exploded. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. 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