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CN-224216832-U - Negative electrode relay detection circuit and battery management system

CN224216832UCN 224216832 UCN224216832 UCN 224216832UCN-224216832-U

Abstract

The application discloses a negative electrode relay detection circuit and a battery management system, wherein the negative electrode relay detection circuit comprises a power supply, a first resistor, a second resistor, a third resistor, a first transistor, a second transistor and a negative electrode relay, wherein the first end of the first resistor is connected with the positive electrode of the power supply, the second end of the first resistor is connected with the first end of the second resistor, the second end of the second resistor is connected with the negative electrode of the power supply, a test point is arranged between the first resistor and the second resistor and is used for detecting abnormality of the negative electrode relay, the first end of the third resistor is connected with the test point, the second end of the third resistor is connected with the positive electrode of the first transistor, the negative electrode of the first transistor is connected with the first end of the negative electrode relay, the positive electrode of the second transistor is connected with the second end of the second resistor, and the negative electrode of the second transistor is connected with the negative electrode of the power supply.

Inventors

  • XU TONGHUI
  • Li Peijiong

Assignees

  • 欣旺达动力科技股份有限公司

Dates

Publication Date
20260508
Application Date
20250509

Claims (10)

  1. 1. The negative electrode relay detection circuit is characterized by comprising a power supply (10), a first resistor (1), a second resistor (2), a third resistor (3), a first transistor (8), a second transistor (9) and a negative electrode relay (5); The first end of the first resistor (1) is connected with the positive electrode of the power supply (10), the second end of the first resistor (1) is connected with the first end of the second resistor (2), the second end of the second resistor (2) is connected with the negative electrode of the power supply (10), a test point (7) is arranged between the first resistor (1) and the second resistor (2), and the test point (7) is used for detecting the abnormality of the negative relay (5); The first end of the third resistor (3) is connected with the test point (7), the second end of the third resistor (3) is connected with the positive electrode end of the first transistor (8), and the negative electrode end of the first transistor (8) is connected with the first end of the negative electrode relay (5); The positive terminal of the second transistor (9) is connected with the second terminal of the second resistor (2), the negative terminal of the second transistor (9) is connected with the negative terminal of the first transistor (8), and the second terminal of the negative relay (5) is connected with the negative terminal of the power supply (10).
  2. 2. The negative relay detection circuit according to claim 1, wherein at least one of the first transistor (8) and the second transistor (9) is a clamp diode.
  3. 3. The negative relay detection circuit according to claim 2, wherein, in the case where the first transistor (8) and the second transistor (9) are both the clamp diodes, a difference between the clamp voltage of the first transistor (8) and the clamp voltage of the second transistor (9) is smaller than a voltage value of the power supply (10).
  4. 4. A negative relay detection circuit according to claim 3, characterized in that the clamping voltage of the first transistor (8) and the clamping voltage of the second transistor (9) are equal.
  5. 5. The negative electrode relay detection circuit according to claim 1, wherein a ratio between a resistance value of the first resistor (1) and a resistance value of the third resistor (3) is B, satisfying 1.7≤b≤33; And/or the ratio between the resistance value of the first resistor (1) and the resistance value of the second resistor (2) is C, and C is more than or equal to 0.5 and less than or equal to 33.
  6. 6. The negative relay detection circuit according to claim 1, further comprising a fourth resistor (4), wherein a first terminal of the fourth resistor (4) is connected to the negative terminal of the first transistor (8), and a second terminal of the fourth resistor (4) is connected to the first terminal of the negative relay (5).
  7. 7. The negative relay detection circuit according to claim 6, wherein the fourth resistor (4) includes a plurality of sub resistors (41); A plurality of sub resistors (41) are connected in series to form a resistor string, a first end of the resistor string is connected with the negative electrode end of the first transistor (8), and a second end of the resistor string is connected with the first end of the negative electrode relay (5).
  8. 8. The negative relay detection circuit according to claim 7, wherein the resistance value of each of the sub-resistors (41) is equal.
  9. 9. The negative relay detection circuit according to claim 1, further comprising a collection member electrically connected to the detection point (7), the collection member being configured to detect a voltage at the detection point (7).
  10. 10. A battery management system, characterized by comprising the negative electrode relay detection circuit according to any one of claims 1 to 9, a battery pack (6), and a negative electrode sampling module (11); The negative electrode of the battery pack (6) is connected with the second end of the negative electrode relay (5), the positive electrode of the battery pack (6) is connected with the first end of the negative electrode sampling module (11), and the second end of the negative electrode sampling module (11) is connected with the first end of the negative electrode relay (5).

Description

Negative electrode relay detection circuit and battery management system Technical Field The application belongs to the technical field of circuit detection, and particularly relates to a negative electrode relay detection circuit and a battery management system. Background Along with the higher requirements of the new energy automobile industry on the safety, stability and reliability of a Battery management system (Battery MANAGEMENT SYSTEM, BMS), the accuracy of a high-voltage loop detection function has become a core element affecting the overall performance of the system, and the state diagnosis of key components such as a relay is particularly important. In the switching process or the circuit state conversion process between the battery pack and the negative electrode relay, the transient voltage disturbance phenomenon of the negative electrode relay is caused due to the time lag effect existing in charge redistribution of the vehicle body distributed capacitance. However, the problem of negative pressure fluctuation capturing failure commonly exists in the prior art, so that negative pressure faults of the negative electrode relay cannot be identified, and the system safety of the high-voltage battery is further affected. Disclosure of utility model The application aims to provide a negative electrode relay detection circuit and a battery management system, which can solve the problem that the negative voltage fault of a negative electrode relay cannot be identified in the prior art. In order to solve the technical problems, the application is realized as follows: According to the embodiment of the application, the negative relay detection circuit comprises a power supply, a first resistor, a second resistor, a third resistor, a first transistor, a second transistor and a negative relay, wherein the first end of the first resistor is connected with the positive electrode of the power supply, the second end of the first resistor is connected with the first end of the second resistor, the second end of the second resistor is connected with the negative electrode of the power supply, a test point is arranged between the first resistor and the second resistor and used for detecting abnormality of the negative relay, the first end of the third resistor is connected with the test point, the second end of the third resistor is connected with the positive electrode end of the first transistor, the negative electrode end of the first transistor is connected with the first end of the negative relay, the positive electrode end of the second transistor is connected with the second end of the second resistor, and the negative electrode end of the second transistor is connected with the negative electrode end of the first transistor. Optionally, at least one of the first transistor and the second transistor is a clamp diode. Optionally, in the case where the first transistor and the second transistor are both the clamp diode, a difference between the clamp voltage of the first transistor and the clamp voltage of the second transistor is smaller than a voltage value of the power supply. Optionally, the clamping voltage of the first transistor is equal to the clamping voltage of the second transistor. Optionally, the ratio between the resistance value of the first resistor and the resistance value of the third resistor is B, which is 1.7-33, and/or the ratio between the resistance value of the first resistor and the resistance value of the second resistor is C, which is 0.5-33. Optionally, the circuit further comprises a fourth resistor, wherein the first end of the fourth resistor is connected with the negative electrode end of the first transistor, and the second end of the fourth resistor is connected with the first end of the negative electrode relay. Optionally, the fourth resistor comprises a plurality of sub-resistors, the plurality of sub-resistors are connected in series to form a resistor string, a first end of the resistor string is electrically connected with the negative electrode end of the first transistor, and a second end of the resistor string is connected with the first end of the negative electrode relay. Optionally, the resistance value of each of the sub-resistors is equal. Optionally, the device further comprises a collection piece, wherein the collection piece is electrically connected with the detection point and is used for detecting the voltage of the detection point. In a second aspect, an embodiment of the present application provides a battery management system, including the negative electrode relay detection circuit, the battery pack and the negative electrode sampling module described in the foregoing embodiments, where a negative electrode of the battery pack is connected to a second end of the negative electrode relay, and a positive electrode of the battery pack is connected to a first end of the negative electrode sampling module, and a second end of the negative electrode sampl