Ni-MH battery pack

　　Ni-MH battery pack manufacturers interpret the consequences of BMS failure modes of Ni-MH battery pack management systems

　　Ni-MH battery pack manufacturers interpret the consequences of BMS failure modes of Ni-MH battery pack management systems. Studying the failure mode of the power BMS Ni-MH battery pack management system is of vital significance to improving battery life, safety and reliability of electric vehicles, and reducing the cost of using electric vehicles. Power battery system failure modes can be divided into three different levels of failure modes, namely battery cell failure mode, battery management system failure mode, and Pack system integration failure mode.

　　Ni-MH battery pack manufacturers interpret the consequences of BMS failure modes of Ni-MH battery pack management systems

　　The failure of a Ni-MH battery pack cell is not only related to the battery itself, but also to the failure of the Ni-MH battery pack management system BMS. The following Ni-MH battery pack manufacturers explain that BMS battery management system failure modes can also cause serious accidents:

　　1. BMS voltage detection failure causes battery overcharge or overdischarge:

　　The voltage detection line fails due to connection, crimping process or poor contact. The BMS has no voltage information and does not stop when charging. Overcharged batteries will catch fire and explode. Lithium iron phosphate will mostly just smoke when overcharged to above 5V, but ternary batteries will explode once overcharged.

　　Moreover, overcharging can easily cause the electrolyte in the Ni-MH battery pack to decompose and release gas, causing the battery to bulge, or even smoke and catch fire in severe cases; overdischarging of the battery can cause damage to the molecular structure of the positive electrode material of the battery, resulting in inability to charge.

　　2. BMS current detection failure

　　The Hall sensor fails, the BMS Ni-MH battery pack management system cannot collect current, the SOC cannot be calculated, and the deviation is large. Failure of current detection may result in excessive charging current. The charging current is large, the internal heat of the battery cell is large, and the temperature exceeds a certain temperature, which will cause the curing capacity of the separator to attenuate, seriously affecting the life of the Ni-MH battery pack.

　　3. BMS temperature detection failure

　　Temperature detection failure causes the operating temperature of lithium batteries to be too high, causing irreversible reactions in the battery, which has a great impact on battery capacity and internal resistance. The calendar life of the battery cell is directly related to the temperature. The number of cycles at 45 degrees is half that at 25 degrees. In addition, the battery is prone to bulging, leakage, explosion and other problems if the temperature is too high.

　　4. Insulation monitoring failure

　　Insulation failure will occur when the power Ni-MH battery pack system is deformed or leaks. If the BMS Ni-MH battery pack management system is not detected, electric shock may occur. Therefore, the BMS system should have the highest requirements for monitoring sensors. Avoiding monitoring system failure can greatly improve the safety of power lithium batteries.

　　5. Communication failure due to electromagnetic compatibility issues

　　For the BMS system, electromagnetic compatibility mainly assesses its ability to resist electromagnetic interference. Electromagnetic interference will cause BMS communication failure and cause the above problems.

　　The role of BMS battery management system

　　The importance of the battery management system BMS is self-evident. Many new energy vehicle companies at home and abroad regard the battery management system as the core technology of the company. The most famous example is the well-known Tesla. The battery management system is Tesla's independently developed core technologies, and most of the core intellectual property rights applied for by Tesla between 2008 and 2017 are related to battery management systems. This shows the importance of battery management systems for new energy vehicles.

　　With long-term use, aging and other factors, the inconsistency between batteries will become more obvious, which may affect battery efficiency and life at least, or cause spontaneous fires that threaten life and property safety. At this time, the BMS Ni-MH battery pack management system is required to intervene. .

　　The BMS collects, processes, and stores important information during the operation of the Ni-MH battery pack pack in real time, exchanges information with external devices such as vehicle controllers, and solves key issues such as safety, availability, ease of use, and service life in the Ni-MH battery pack system.

　　Summary: Based on the various failure modes of the power battery system mentioned above, scientific researchers and Ni-MH battery pack manufacturers need to improve the safety of Ni-MH battery pack cells through continuous improvement of processes and technologies. BMS system manufacturers must fully understand the performance of the battery and based on the safety of the power battery Design principles to design a safe and reliable battery system.

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