Charge control method for power lithium ion storage battery

Abstract

The invention provides a charge control method for a power lithium ion storage battery, which relates to the technical field of the storage battery. In the beginning of charging, the battery is rapidly charged by using a larger current: when a BMS detects any one of single cells in the battery reaches a set voltage, the BMS sends a control signal by a communication interface to make a charger reduce the charging current; after the storage battery is charged for a certain time, the voltage of the single cell begins to rise again and when any one of single cells reaches the set value, the BMS sends the control signal again to make the charger reduce the charging current; the steps are repeated sequentially until the current value reaches a small value; and when each cell reaches the set voltage, the charger is turned off. The charge control method can guarantee that all the cells are fully charged in shorter time without overcharging, has the function of maintaining the cells due to low current charging at the final stage, has excellent correction effect on inconsistent charge states of the cells due to inconsistent self-discharge rates and greatly prolongs the circulation life of the battery.

Description

technical field [0001] The invention relates to the technical field of storage batteries, in particular to the technical field of charging lithium-ion storage batteries. Background technique [0002] With the rise of electric vehicles, lithium-ion power batteries are also becoming larger and more complex, especially for pure electric vehicles that require a lot of power, with a capacity of hundreds of amperes and a voltage of hundreds of volts. In order to meet the above requirements, many batteries need to be connected in series, and some battery packs require thousands of batteries, and at least 60 series series are required to achieve ideal motor efficiency and power characteristics. In order to ensure the safe operation of the battery, it is necessary to install a battery management system (battery management system, referred to as BMS) to monitor the status of each battery in real time. It turned out that the battery was damaged by charging, and many battery accidents ...

AI Technical Summary

Problems solved by technology

But for the battery pack, the slight difference between the battery cells makes the battery pack produce a huge voltage difference during the constant voltage charging process, especially when the number of series connection is large, the voltage value of a single battery is covered under the terminal voltage , the charger cannot be detected at all, and overcharging is prone to occur. The traditional BMS detects and monitors the battery pack in isolation. When this happens, it will directly disconnect the charging circuit and stop charging, resulting in the battery pack not being fully charged.

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