Voltage measuring system and method for battery

Abstract

The invention discloses a voltage measuring system and a voltage measuring method, which are applied to a battery comprising a plurality of battery units. The voltage measuring system comprises a switch matrix, a fully different amplifier and an analog-to-digital converter, wherein the switch matrix is connected with the battery unit and comprises a first group of switches and a second group of switches; the fully different amplifier is connected with the switch matrix, comprises a fully different operational amplifier and a resistor pair and is used for amplifying voltage difference between the anode and the cathode of a corresponding battery unit when a switch pair in the switch matrix is switched off; the analog-to-digital converter is connected with the fully different amplifier and comprises an output multiplexer for receiving a chopping signal; when the chopping signal is in a first value, a first switch pair in the switch matrix is switched off; and when the chopping signal is in a second value, a second switch pair in the switch matrix is switched off. By adopting the voltage measuring system and the method disclosed by the invention, offset voltage of the fully different amplifier and input offset voltage of the analog-to-digital converter can be eliminated automatically, and the voltage measuring accuracy is enhanced effectively.

Description

technical field [0001] The invention relates to a battery measuring system, in particular to a battery voltage measuring system and method. Background technique [0002] figure 1 Shown is a block diagram of a prior art voltage measurement system 100 . The voltage measurement system 100 includes a battery 110 , a switch matrix 120 , a differential amplifier 130 and an analog-to-digital converter 140 . Battery 110 includes battery cells 111-118. The switch matrix 120 includes switches 120_iA (i=1, . . . , 9), 120_iB (i=1, . . . , 8). The voltage measurement process of each battery cell is divided into an automatic zero elimination step and a measurement step. For example, when measuring the voltage of the battery cell 111 , in the auto-zeroing step, the switch 120_1B and the switch 120_2A are closed, the input voltage of the differential amplifier 130 is zero, and the measured voltage at this time is the output offset voltage of the differential amplifier 130 . In the mea...

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Problems solved by technology

Therefore, even if the automatic zero elimination step is adopted, the input offset voltage of the analog-to-digital converter 140 cannot be eliminated, which affects the measurement accuracy of the voltage

[0022] In addition, if the voltage at the positive input terminal of the operational amplifier 139 is disturbed by noise, the output voltage of the differential amplifier 130 will be disturbed, and finally the voltage measurement of the battery cell is also disturbed by noise.

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