Battery high voltage sampling circuit and battery management system
The present disclosure provides a battery high voltage sampling circuit and a battery management system. The battery high voltage sampling circuit includes a positive relay, a negative relay, a first positive sampling unit, a first negative sampling unit and a reference voltage terminal, wherein: a first terminal of the positive relay is connected to a positive electrode of a power battery pack to be detected, a first terminal of the negative relay is connected to a negative electrode of the power battery pack to be detected, and both of the first positive sampling unit and the first negative sampling unit are connected to the reference voltage terminal.
1. A battery high voltage sampling circuit comprising a positive relay, a negative relay, a first positive sampling unit, a first negative sampling unit, a second positive sampling unit, a second negative sampling unit and a reference voltage terminal, wherein:
a first terminal of the positive relay is connected to a positive electrode of a power battery pack to be detected, a first terminal of the negative relay is connected to a negative electrode of the power battery pack to be detected, and both of the first positive sampling unit and the first negative sampling unit are connected to the reference voltage terminal;
the first positive sampling unit is configured to acquire a first positive sampled signal at the first terminal of the positive relay;
the first negative sampling unit is configured to acquire a first negative sampled signal at the first terminal of the negative relay;
both of the second positive sampling unit and the second negative sampling unit are connected to the reference voltage terminal;
the second positive sampling unit is configured to acquire a second positive sampled signal of the power battery pack at a second terminal of the positive relay; and
the second negative sampling unit is configured to acquire a second negative sampled signal of the power battery pack at a second terminal of the negative relay.
2. The battery high voltage sampling circuit of claim 1 , further comprising a first positive sampling point and a first negative sampling point, wherein:
the first positive sampling unit is further configured to provide the first positive sampled signal to the first positive sampling point; and
the first negative sampling unit is further configured to provide the first negative sampled signal to the first negative sampling point.
3. The battery high voltage sampling circuit of claim 2 , wherein:
a first terminal of the first positive sampling unit is connected to the first terminal of the positive relay and the positive electrode of the power battery pack to be detected, and a second terminal of the first positive sampling unit is connected to the first positive sampling point and the reference voltage terminal; and
a first terminal of the first negative sampling unit is connected to the first terminal of the negative relay and the negative electrode of the battery pack to be detected, and a second terminal of the first negative sampling unit is connected to the first negative sampling point and the reference voltage terminal.
4. The battery high voltage sampling circuit of claim 2 , further comprising a first voltage pull-up unit, wherein:
the first voltage pull-up unit is connected to the first negative sampling point, and the first voltage pull-up unit is configured to pull up the first negative sampled signal to be a positive voltage signal.
5. The battery high voltage sampling circuit of claim 4 , wherein:
the first voltage pull-up unit comprises a first DC voltage source and a fifth resistor network; and
a terminal of the fifth resistor network is connected to the first negative sampling point, and the other terminal of the fifth resistor network is connected to the first DC voltage source.
6. The battery high voltage sampling circuit of claim 2 , wherein:
the first positive sampling unit comprises a first resistor network and a second resistor network in series;
a terminal of the first resistor network is connected to the first terminal of the positive relay and the positive electrode of the power battery pack to be detected, and the other terminal of the first resistor network is connected to the first positive sampling point and a terminal of the second resistor network; and
the other terminal of the second resistor network is connected to the reference voltage terminal.
7. The battery high voltage sampling circuit of claim 6 , wherein:
the first positive sampling unit further comprises a first switch; and
a terminal of the first resistor network is connected, via the first switch, to the positive electrode of the power battery pack to be detected.
8. The battery high voltage sampling circuit of claim 2 , wherein:
the first negative sampling unit comprises a third resistor network and a fourth resistor network in series;
a terminal of the third resistor network is connected to the reference voltage terminal, and the other terminal of the third resistor network is connected to the first negative sampling point and a terminal of the fourth resistor network; and
the other terminal of the fourth resistor network is connected to the first terminal of the negative relay and the negative electrode of the power battery pack to be detected.
9. The battery high voltage sampling circuit of claim 8 , wherein:
the first negative sampling unit further comprises a second switch; and
a terminal of the third resistor network is connected to the reference voltage terminal via the second switch.
10. The battery high voltage sampling circuit of claim 1 , further comprising a second positive sampling point and a second negative sampling point, wherein:
the second positive sampling unit is further configured to provide the second positive sampled signal to the second positive sampling point; and
the second negative sampling unit is further configured to provide the second negative sampled signal to the second negative sampling point.
11. The battery high voltage sampling circuit of claim 10 , wherein:
a first terminal of the second positive sampling unit is connected to the second terminal of the positive relay, and a second terminal of the second positive sampling unit is connected to the second positive sampling point and the reference voltage terminal; and
a first terminal of the second negative sampling unit is connected to the second terminal of the negative relay, and a second terminal of the second negative sampling unit is connected to the second negative sampling point.
12. The battery high voltage sampling circuit of claim 10 , further comprising a second voltage pull-up unit, wherein:
the second voltage pull-up unit is connected to the second negative sampling point, and the second voltage pull-up unit is configured to pull up the second negative sampled signal to be a positive voltage signal.
13. The battery high voltage sampling circuit of claim 12 , wherein:
the second voltage pull-up unit comprises a second DC voltage source and a tenth resistor network; and
a terminal of the tenth resistor network is connected to the second negative sampling point, and the other terminal of the tenth resistor network is connected to the second DC voltage source.
14. The battery high voltage sampling circuit of claim 10 , wherein:
the second positive sampling unit comprises a sixth resistor network and a seventh resistor network in series;
a terminal of the sixth resistor network is connected to the second terminal of the positive relay, and the other terminal of the sixth resistor network is connected to the second positive sampling point and a terminal of the seventh resistor network; and
the other terminal of the seventh resistor network is connected to the reference voltage terminal.
15. The battery high voltage sampling circuit of claim 14 , wherein:
the second positive sampling unit further comprises a third switch; and
a terminal of the sixth resistor network is connected to the second terminal of the positive relay via the third switch.
16. The battery high voltage sampling circuit of claim 10 , wherein:
the second negative sampling unit comprises an eighth resistor network and a ninth resistor network in series;
a terminal of the eighth resistor network is connected to the reference voltage terminal, and the other terminal of the eighth resistor network is connected to the second negative sampling point and a terminal of the ninth resistor network; and
the other terminal of the ninth resistor network is connected to the second terminal of the negative relay.
17. The battery high voltage sampling circuit of claim 16 , wherein:
the second negative sampling unit further comprises a fourth switch; and
a terminal of the eighth resistor network is connected to the reference voltage terminal via the fourth switch.
18. A battery management system, comprising the battery high voltage sampling circuit of claim 1 and a processor connected to the battery high voltage circuit, wherein the processor is configured to:
calculate a voltage at the first terminal of the positive relay based on the first positive sampled signal;
calculate a voltage at the first terminal of the negative relay based on the first negative sampled signal; and
obtain a relay-input voltage of the power battery pack to be detected, based on the voltage at the first terminal of the positive relay and the voltage at the first terminal of the negative relay, wherein the relay-input voltage of the power battery pack to be detected is a voltage between the first terminal of the positive relay and the first terminal of the negative relay.
19. The battery management system of claim 18 , wherein the processor is further configured to:
calculate a voltage at the second terminal of the positive relay based on the second positive sampled signal;
calculate a voltage at the second terminal of the negative relay based on the second negative sampled signal; and
obtain a relay-output voltage of the power battery pack to be detected, based on the voltage at the second terminal of the positive relay and the voltage at the second terminal of the negative relay, wherein the relay-output voltage of the power battery pack to be detected is a voltage between the second terminal of the positive relay and the second terminal of the negative relay.