12v lithium battery protection circuit design requirements and functions. 12V lithium batteries are widely used in various fields such as digital products, power tools, electric bicycles, electric vehicles, double power supplies and energy storage. The design of lithium battery protection circuit is very important. We require the 12v lithium battery power protection chip to achieve the following most basic functions: overcharge protection, over-discharge protection, over-current protection and short-circuit protection. Improve the service life of lithium batteries and ensure the safe use of batteries.

　　What is a 12v lithium battery?

　　12v lithium battery is made of 3 or 4 lithium batteries connected in series. The capacity of the combined battery pack is determined based on the capacity of a single cell or the capacity of batteries connected in parallel. It is a new type of battery that is safe and environmentally friendly.

　　12v lithium battery parameters

　　Combination method: ICR18500-3S2P

　　Nominal voltage: 11.1V

　　Discharge voltage: 11.1V-12.6V

　　Conventional discharge current is: 0-2A, large capacity is 3-4A

　　Nominal capacity: in MahA, available in various sizes

　　Standard continuous discharge current: 0.2C

　　Maximum continuous discharge current: 1C

　　Working temperature: Charging: 0~45℃

　　Discharge: -20~60℃

　　12v lithium battery protection circuit design requirements

　　Due to the high energy density of 12v lithium batteries, in the overcharged state, the energy will be excess after the battery temperature rises, so the electrolyte decomposes to produce gas, which can easily increase the internal pressure and cause the risk of spontaneous combustion or rupture; conversely, in the overdischarged state, , the decomposition of the electrolyte leads to the deterioration of battery characteristics and durability, reduces the number of recharges, and shortens the service life of the battery. Therefore, the protection of 12v lithium batteries is very important. 12v lithium battery applications must have a battery protection chip to prevent overcharge, overdischarge and overcurrent of the battery.

　　The 12v lithium battery protection circuit will increase the additional loss of battery energy and reduce the battery's application time. This requires the lithium battery protection circuit to achieve low power consumption with high precision. In addition to completing basic functions such as overcharge protection, over-discharge protection and over-current protection, a lithium battery protection chip must also meet the following requirements:

　　(1) Ultra-low power consumption. When the lithium battery protection circuit is working, the power consumption it consumes is the loss of the battery. Therefore, we need to minimize the power consumption of the lithium battery protection circuit.

　　(2) Highly accurate voltage detection. In order for the lithium battery protection circuit to respond correctly to different working states of the battery, the protection circuit must be able to accurately detect voltage parameters such as overcharge protection voltage and over-discharge protection voltage.

　　(3) Works correctly under a wide voltage range. Since the power supply voltage of the lithium battery protection circuit is the battery voltage, and the battery voltage can float within a wide range, the lithium battery protection circuit is required to work correctly within this voltage range.

　　The 12v lithium battery protection circuit needs to have the following functions

　　(1) If the charging voltage exceeds the maximum allowed value of the battery, a battery discharge circuit can be provided.

　　(2) If the discharge voltage is lower than the minimum allowed value of the battery, a battery charging circuit can be provided. then disconnect the battery from the external circuit, and then disconnect the battery from the external circuit, and

　　(3) If the charging and discharging current of the 12v lithium battery is greater than the limit value, cut off the connection between the battery and the external circuit.

　　(4) When the 12v lithium battery returns to normal state, the protection circuit should be able to release the protection state accordingly so that the battery can continue to work normally.

　　What are the main cathode materials of 12v lithium battery?

　　At present, my country's 12v lithium battery cathode materials mainly include lithium cobalt oxide and ternary materials.

　　Lithium manganate and lithium iron phosphate. The application fields of cathode materials are clearly differentiated. At present, lithium cobalt oxide is still the main cathode material in the field of small lithium batteries and is mainly used in traditional 3C fields. Ternary materials and lithium manganate are mainly used in small lithium batteries and are used in Japan and South Korea. The technology of power batteries is relatively mature and is mainly used in fields such as power tools, electric bicycles and electric vehicles. Iron phosphate 12V lithium batteries are used in the field of power batteries in China and are the direction of future energy storage battery development. They are mainly used in base stations and data Central energy storage, home energy storage, wind and photovoltaic energy storage and other fields.

　　The ternary material combines the advantages of lithium cobalt oxide, lithium nickel oxide and lithium manganate and has a price advantage. However, its application is affected by the price of cobalt. When the cobalt price is at a high level, the price of the ternary material is higher than that of lithium cobalt oxide. Low, it has strong market competitiveness; but when the price of cobalt is at a low level, the advantages of ternary materials compared to lithium cobalt oxide are greatly reduced. At present, there is a general development trend of lithium cobalt oxide materials being replaced by ternary materials.

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