Cell sampling circuit, circuit fault early warning method, and battery management system
View Patent ↗A cell sampling circuit includes a plurality of target units sequentially connected in a series connection in a daisy-chain communication manner and one or more transformer units each connected between two successive target units of the plurality of target units. Each of the target units is configured to acquire an impedance of at least one transformer unit connected to the target unit, and judge, based on the acquired impedance, whether to perform circuit abnormality early warning.
1. A cell sampling circuit, comprising:
a plurality of target units sequentially connected in a series connection in a daisy-chain communication manner, one of the plurality of target units arranged at a first place in the series connection being a main control unit, and the other of the plurality of target units being cell sampling units; and
one or more transformer units each connected between two successive target units of the plurality of target units;
wherein each of the target units is configured to:
acquire an impedance of at least one transformer unit connected to the target unit; and
judge, based on the acquired impedance, whether to perform circuit abnormality early warning.
2. The cell sampling circuit according to claim 1 , wherein:
for two successive target units connected to one transformer unit, an upstream one of the two successive target units is connected to a transformer input module of the one transformer unit, and a downstream one of the two successive target units is connected to a transformer output module of the transformer unit; and
each of the target units is configured to:
acquire an impedance of a target module connected to the target unit, the target module being determined based on a connection relationship between the target unit and the at least one transformer unit connected to the target unit; and
judge, based on the acquired impedance, whether to perform circuit abnormality early warning.
3. The cell sampling circuit according to claim 2 , wherein for one of the cell sampling units, the target module comprises a transformer output module connected to the one of the cell sampling units and a transformer input module connected to the one of the cell sampling units, and the acquired impedance comprises an impedance of the transformer output module and an impedance of the transformer input module.
4. The cell sampling circuit according to claim 2 , wherein for the main control unit, the target module comprises a transformer input module connected to the main control unit, and the acquired impedance comprises an impedance of the transformer input module.
5. The cell sampling circuit according to claim 2 , wherein each of the target units is configured to perform circuit abnormality early warning in response to determining that the acquired impedance of the target module reaches an impedance threshold corresponding to the target module.
6. The cell sampling circuit according to claim 5 , wherein each of the target units is configured to determine an abnormal transformer unit, and issue a circuit abnormality early warning for the abnormal transformer unit, the abnormal transformer unit being a transformer unit to which the target module having the impedance reaching the corresponding impedance threshold belongs.
7. The cell sampling circuit according to claim 2 , wherein:
the transformer output module comprises: a winding, a first switch element, a second switch element, a first connection circuit, and a second connection circuit;
a first end of the winding is connected to a first end of the first switch element through the first connection circuit, and a second end of the winding is connected to a first end of the second switch element through the second connection circuit; and
a second end of the first switch element and a second end of the second switch element are connected to one target unit of the plurality of target units.
8. The cell sampling circuit according to claim 7 , wherein:
the one target unit comprises: a first voltage sampling circuit, a second voltage sampling circuit, a voltage adjustment circuit, and a control chip;
a first end of the voltage adjustment circuit is connected to a first node, and a second end of the voltage adjustment circuit is connected to a ground wire;
a first end of the first voltage sampling circuit is connected to the first node, and a second end of the first voltage sampling circuit is connected to a first pin of the control chip;
a first end of the second voltage sampling circuit is connected to a second node, and a second end of the second voltage sampling circuit is connected to a second pin of the control chip;
the first node is connected to the second end of the first switch element, and is connected to a third pin of the control chip; and
the second node is connected to the second end of the second switch element, and is connected to a fourth pin of the control chip.
9. The cell sampling circuit according to claim 8 , wherein the control chip is configured to collect a first sampling voltage corresponding to the first voltage sampling circuit and a second sampling voltage corresponding to the second voltage sampling circuit, and determine an impedance of the transformer output module connected to the one target unit based on the first sampling voltage, the second sampling voltage, and a resistance of the voltage adjustment circuit.
10. The cell sampling circuit according to claim 8 , wherein:
the voltage adjustment circuit is a first voltage adjustment circuit;
the one target unit further comprises: a second voltage adjustment circuit and a third voltage sampling circuit;
a first end of the second voltage adjustment circuit is connected to the second node, and a second end of the second voltage adjustment circuit is connected to a first end of the third voltage sampling circuit; and
a second end of the third voltage sampling circuit is connected to a fifth pin of the control chip.
11. The cell sampling circuit according to claim 10 , wherein:
the first voltage sampling circuit is configured to output a first sampling voltage, the second voltage sampling circuit is configured to output a second sampling voltage, and the third voltage sampling circuit is configured to output a third sampling voltage; and
the control chip is configured to:
collect the second sampling voltage corresponding to the second voltage sampling circuit and the third sampling voltage corresponding to the third voltage sampling circuit, and determine the impedance of the transformer output module connected to the one target unit based on the second sampling voltage, the third sampling voltage, a first resistance of the first voltage adjustment circuit, and a second resistance of the second voltage adjustment circuit; or
collect the first sampling voltage corresponding to the first voltage sampling circuit and the third sampling voltage corresponding to the third voltage sampling circuit, and determine the impedance of the transformer output module connected to the one target unit based on the first sampling voltage, the third sampling voltage, the first resistance of the first voltage adjustment circuit, and the second resistance of the second voltage adjustment circuit.
12. The cell sampling circuit according to claim 7 , wherein an impedance of the transformer output module is a sum of an impedance of the winding, an impedance of the first switch element, an impedance of the second switch element, an impedance of the first connection circuit, and an impedance of the second connection circuit of the transformer output module under daisy-chain communication.
13. The cell sampling circuit according to claim 2 , wherein:
the transformer input module comprises: a winding, a first switch element, and a second switch element;
a first end of the winding is connected to a first end of the first switch element, and a second end of the winding is connected to a first end of the second switch element; and
a second end of the first switch element and a second end of the second switch element are connected to one target unit of the plurality of target units.
14. The cell sampling circuit according to claim 13 , wherein:
the one target unit comprises: a first voltage sampling circuit, a second voltage sampling circuit, a voltage adjustment circuit, and a control chip;
a first end of the voltage adjustment circuit is connected to a first node, and a second end of the voltage adjustment circuit is connected to a ground wire;
a first end of the first voltage sampling circuit is connected to the first node, and a second end of the first voltage sampling circuit is connected to a first pin of the control chip;
a first end of the second voltage sampling circuit is connected to a second node, and a second end of the second voltage sampling circuit is connected to a second pin of the control chip;
the first node is connected to the second end of the first switch element, and is connected to a third pin of the control chip; and
the second node is connected to the second end of the second switch element, and is connected to a fourth pin of the control chip.
15. The cell sampling circuit according to claim 14 , wherein the control chip is configured to collect a first sampling voltage corresponding to the first voltage sampling circuit and a second sampling voltage corresponding to the second voltage sampling circuit, and determine an impedance of the transformer input module connected to the one target unit based on the first sampling voltage, the second sampling voltage, and a resistance of the voltage adjustment circuit.
16. The cell sampling circuit according to claim 14 , wherein:
the voltage adjustment circuit is a first voltage adjustment circuit;
the target unit further comprises: a second voltage adjustment circuit and a third voltage sampling circuit;
a first end of the second voltage adjustment circuit is connected to the second node, and a second end of the second voltage adjustment circuit is connected to a first end of the third voltage sampling circuit; and
a second end of the third voltage sampling circuit is connected to a fifth pin of the control chip.
17. The cell sampling circuit according to claim 16 , wherein:
the first voltage sampling circuit is configured to output a first sampling voltage, the second voltage sampling circuit is configured to output a second sampling voltage, and the third voltage sampling circuit is configured to output a third sampling voltage; and
the control chip is configured to:
collect the third sampling voltage and one of the first sampling voltage and the second sampling voltage, and determine an impedance of the transformer input module connected to the one target unit based on the third sampling voltage, a first resistance of the first voltage adjustment circuit, a second resistance corresponding to the second voltage adjustment circuit, and the one of the first sampling voltage and the second sampling voltage.
18. The cell sampling circuit according to claim 13 , wherein an impedance of the transformer input module is a sum of an impedance of the winding, an impedance of the first switch element, and an impedance of the second switch element of the transformer input module under daisy-chain communication.
19. A circuit fault early warning method, applied to a cell sampling circuit, wherein the cell sampling circuit comprises a plurality of target units sequentially connected in a series connection in a daisy-chain communication manner, one or more transformer units each connected between every two successive target units of the plurality of target units, and one of the plurality of target units arranged at a first place in the series connection being a main control unit, and the other of the plurality of target units being cell sampling units, the method comprising, for one target unit of the plurality of target units:
acquiring an impedance of at least one transformer unit connected to the target unit; and
judging, based on the acquired impedance, whether to perform circuit abnormality early warning.
20. A battery management system, comprising a cell sampling circuit comprising:
a plurality of target units sequentially connected in a series connection in a daisy-chain communication manner, one of the plurality of target units arranged at a first place in the series connection being a main control unit, and the other of the plurality of target units being cell sampling units; and
one or more transformer units each connected between two successive target units of the plurality of target units;
wherein each of the target units is configured to:
acquire an impedance of at least one transformer unit connected to the target unit; and
judge, based on the acquired impedance, whether to perform circuit abnormality early warning.