A voltage acquisition circuit for battery management system

Abstract

The invention provides a voltage acquisition circuit for a battery management system, which comprises n acquisition units and a controller; the acquisition units comprise batteries Ci, control switches Qi1 and loop switches Qi2; the batteries Ci of the adjacent acquisition units are connected in series in sequence through positive poles and negative poles; the negative poles of the batteries Ci are connected with common terminals GND; the positive poles of the batteries Ci are connected with one ends of resistors R0 through resistor Ri1s; the other ends of the resistors R0 are connected with the common terminals GND; the loop switches Qi2 are connected in series in loops formed by the batteries Ci, the resistors Ri1 and the resistors R0; the control switches Qi1 are connected in parallel between the control ends of the loop switches Qi2 and the common terminals; control ends of the control switches Qi1 are connected with output ends KZi of the controllers; input ends of the controllers are connected with one ends, connected with the resistors Ri1, of the resistors R0; and n is a positive integer larger than or equal to 1; and i is a positive integer less than or equal to n. The voltage acquisition circuit provided by the invention is provided with the control switches Qi1 and the loop switches Qi2, so that the power consumption of the voltage acquisition circuit is reduced, and the discharging speeds of the batteries are basically consistent.

Description

technical field [0001] The invention relates to the field of battery management systems, in particular to a voltage acquisition circuit used in a voltage management system. Background technique [0002] Lithium batteries are more and more used in various industries and fields due to their high energy density, good high and low temperature performance, long cycle life, and no pollution. Since the voltage of a single lithium battery is only 2.8V ~ 4.2V , To obtain a battery with higher voltage and capacity, multiple batteries must be connected in series or in parallel to form a battery pack. Therefore, in order to prevent overcharge or overdischarge of each battery in the battery pack, maintain the voltage of each single battery within a reasonable range, thereby prolonging the service life of the battery pack, and knowing the working status of the battery pack at any time, it is necessary to configure the battery pack A battery management system (BMS). [0003] figure 1 It...

AI Technical Summary

Problems solved by technology

[0019] From the above analysis, we can see that, figure 1 The voltage acquisition circuit in the battery makes the discharge current of each battery different, that is, the discharge speed of each battery is inconsistent, causing the voltage imbalance between the batteries in the battery pack, which becomes more and more obvious as time goes on.

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