Charging and discharging balance device for lithium ion power battery group

Abstract

A charge and discharge balancing device for a power lithium battery pack comprises a charge and discharge module, a plurality of single cell lithium batteries which are connected with each other in series, a single chip, a positive ring, a negative ring, an electrical motor, a balancing battery and fixed contacts used for connecting the positive pole and the negative pole of each single cell lithium battery. The positive poles and the negative poles of each single cell lithium battery are connected with the input terminal of the single chip; the output terminal of the single chip is connected with the charge and discharge module and the electrical motor; a rotating block is fixed on the main shaft of the electrical motor, a positive moving contact electrically connected with the positive ring and a negative moving contact electrically connected with the negative ring are respectively fixed on the rotating block, and the positive moving contact and the negative moving contact are respectively and electrically connected with two adjacent fixed contacts; and the positive pole of the balancing battery is connected with the positive ring and the negative pole of the balancing battery is electrically connected with the negative ring, and the balancing battery can be replaced by an ultra capacitor. The invention has a simple circuit structure and low cost, is safe and reliable, and can prolong the service life of the power lithium battery pack.

Description

technical field [0001] The invention relates to the field of power lithium-ion batteries, in particular to a charge-discharge equalization device for a power lithium-ion battery pack. Background technique [0002] The voltage of the power lithium-ion battery pack is determined by the number of single cells connected in series, while the capacity is determined by the number of single cells connected in parallel. The voltage range of each single battery is 2V ~ 5V (related to the positive electrode material of the power lithium battery), so it is necessary to use the power lithium-ion batteries in series to obtain the required voltage. In an ideal state, the performance of each single battery should be consistent, that is, the voltage of each single battery is certain, but due to factors such as manufacturing errors, self-discharge rate, and the degree of attenuation between single batteries during use, etc. , The voltage capacity between single cells will be different. Durin...

AI Technical Summary

Problems solved by technology

The charging current can be very large. When the bypass part works, the current can be high, but it is limited by the parallel resistance (generally, the upper limit current is 100mA), so this circuit cannot be applied to electric vehicles.

Because when the vehicle brakes, the charging current generated by the brake feedback is much greater than 100mA, and it will reach several amperes (depending on the speed of the vehicle during the feedback braking). This will damage the entire circuit, and the electric vehicle brake feedback charging will lose its function and meaning.

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