Low-cost BMS high-voltage cathode sampling circuit

Abstract

The utility model relates to the technical field of battery management, in particular to a low-cost BMS high-voltage cathode sampling circuit, which comprises a battery pack module PAKE, a safety switch SA, a divider resistor R3, an ADC detection port HVADC, a divider resistor R2, an anti-reverse diode D1, a current-limiting resistor R1, a high-voltage ground end HVGND, a battery pack cathode relay S3, a battery pack BDU positive relay S1 and a battery pack BDU pre-charging relay S2. The positive electrode end of the battery pack module PAKE is connected to the negative electrode end of the battery pack module PAKE; in the low-cost BMS high-voltage negative electrode sampling circuit, the structure of a divider resistor R3, an ADC detection port HVADC, a divider resistor R2, an anti-reverse diode D1, a current-limiting resistor R1 and a battery pack BDU positive relay S1 is optimally designed, so that the BMS can monitor the high-voltage state of a battery pack module PAKE in real time, and the high-voltage state of the battery pack module PAKE is monitored by analyzing a voltage signal collected by the ADC detection port HVADC. And the working state of the battery pack module PAKE and the connection state of the battery pack cathode relay S3 are detected and judged.

Description

Technical Field

[0001] This utility model relates to the field of battery management technology, specifically to a low-cost BMS high-voltage negative electrode sampling circuit. Background Technology

[0002] Battery Management System (BMS) is a battery pack management device used in applications such as electric vehicles and battery storage systems. A BMS monitors and manages battery parameters such as voltage, current, and temperature in real time to ensure the battery operates safely, reliably, and for a long lifespan. In BMS design, the sampling circuit for the high-voltage negative electrode is a crucial component, especially the detection of the high-voltage negative electrode relay's sticking. Traditionally, BMS high-voltage negative electrode detection circuits face numerous technical challenges, including the inability to diagnose relay sticking in real time, the inability to directly identify the relay's closed state, complex detection logic affected by ADC acquisition accuracy, and the need for additional auxiliary conditions for judgment.

[0003] For example, application number CN201721093098.5 discloses a battery high-voltage sampling circuit and a battery management system in which the positive and negative sampling modules are connected to the power battery pack under test at a low voltage common ground, so that the insulation detection circuit does not need to introduce an isolation module, which can avoid introducing new interference signals and improve the accuracy of the sampling signal. However, the real-time detection of the negative relay status is still difficult, and there are also defects in the high accuracy requirements of ADC acquisition and electromagnetic compatibility.

[0004] Therefore, the battery high-voltage sampling circuit disclosed in the above-mentioned utility model patent has the problems of being unable to directly identify the closed state of the high-voltage negative relay, being unable to diagnose the sticking of the negative relay in real time, having a relatively complex circuit detection logic, and being affected by the ADC acquisition accuracy. Utility Model Content

[0005] The purpose of this invention is to provide a low-cost BMS high-voltage negative sampling circuit to solve the technical problems mentioned in the background section.

[0006] To achieve the above objectives, this utility model discloses a low-cost BMS high-voltage negative sampling circuit, including a battery pack module PAKE, a safety switch SA, a voltage divider resistor R3, an ADC detection port HV_ADC, a voltage divider resistor R2, an anti-reverse diode D1, a current-limiting resistor R1, a high-voltage ground terminal HV_GND, a battery pack negative relay S3, a battery pack BDU positive relay S1, and a battery pack BDU pre-charge relay S2. The positive to negative terminals of the battery pack module PAKE are connected in series with the safety switch SA, the voltage divider resistor R3, the voltage divider resistor R2, the anti-reverse diode D1, and the battery pack negative relay S3.

[0007] The voltage divider resistor R3 and the voltage divider resistor R2 are connected in a topology to the ADC detection port HV_ADC;

[0008] The current-limiting resistor R1 is connected in a topology between the voltage divider resistor R2 and the anti-reverse diode D1, and the other end of the current-limiting resistor R1 is connected in series with the high voltage ground terminal HV_GND.

[0009] At the node between the battery pack module PAKE and the safety switch SA, the battery pack BDU positive relay S1 is connected in series. The two ends of the battery pack BDU positive relay S1 are connected in parallel with the battery pack BDU precharge relay S2. The battery pack BDU precharge relay S2 is used to precharge before the battery pack BDU positive relay S1 is closed to prevent current surge caused by direct connection to high voltage.

[0010] Optionally, the high voltage output by the battery pack module PAKE is divided by the voltage divider resistors R3 and R2, so that the ADC detection port HV_ADC detects a voltage signal that has decreased at the node between the voltage divider resistors R3 and R2, that is, the ADC detection port HV_ADC samples it.

[0011] Optionally, the current-limiting resistor R1 limits the current through the ADC detection port HV_ADC to limit the current and protect the ADC circuit from excessive current. The anti-reverse diode D1 prevents current from flowing in reverse and protects the circuit components from damage. The battery pack negative relay S3 controls the connection and disconnection of the negative terminal of the battery pack module PAKE. The battery pack BDU positive relay S1 and the battery pack BDU precharge relay S2 control the connection and disconnection of the positive terminal of the battery pack module PAKE.

[0012] Optionally, the voltage value detected by the ADC detection port HV_ADC is affected by the connection and disconnection of the battery pack BDU positive relay S1, battery pack BDU precharge relay S2, and battery pack negative relay S3. When the battery pack negative relay S3 and the battery pack BDU positive relay S1 are in the disconnected state, the calculation formula for the voltage value detected by the ADC detection port HV_ADC is as follows: In the formula, U ADC U represents the voltage value acquired by the ADC detection port HV_ADC. PAKE The voltage value is represented by the battery pack module PAKE directly acquired by the ordinary ADC acquisition method. R1, R2, and R3 represent the resistance values ​​of the voltage divider resistor R3, the voltage divider resistor R2, and the current limiting resistor R1, respectively. The voltage divider resistor R3, the voltage divider resistor R2, and the current limiting resistor R1 are used for voltage division.

[0013] When the battery pack negative relay S3 and the battery pack BDU positive relay S1 are in the closed state, the formula for calculating the voltage value detected by the ADC detection port HV_ADC is as follows: In the formula, U ADC U represents the voltage value acquired by the ADC detection port HV_ADC. PAKE This represents the voltage value acquired directly by the battery pack module PAKE using a standard ADC acquisition method. R1 and R2 represent the resistance values ​​of the voltage divider resistors R3 and R2, respectively, and these resistors are used for voltage division. Furthermore, through two different voltage division methods, U... PAKE The total voltage of the battery pack module PAKE and the voltage value U collected by the ADC detection port HV_ADC are obtained. ADC The comparison is performed to determine whether the relay status is stuck.

[0014] Optionally, the battery pack BDU positive relay S1 is model GIGAVACGX14, with a rated voltage of 300V and a rated current of 200A, to control the high-voltage positive circuit output; the battery pack BDU precharge relay S2 is model OmronG8P-1A4P, with a rated voltage of 300V and a rated current of 30A, to control the high-voltage precharge circuit output; and the battery pack negative relay S3 is model Tyco EV200AAANA, with a rated voltage of 300V DC and a rated current of 200A, to control the high-voltage negative circuit output.

[0015] Optionally, the voltage divider resistor R3 has a resistance of 990KΩ and an accuracy of 0.1%, and the voltage divider resistor R2 has a resistance of 10KΩ and an accuracy of 0.1%, to ensure the accuracy and stability of the voltage division ratio. The battery pack module PAKE has a resistance range of 1-10KΩ and an accuracy of 1%, to ensure the reliability of the current limiting.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] This low-cost BMS high-voltage negative electrode sampling circuit optimizes the structure of the voltage divider resistor R3, the ADC detection port HV_ADC, the voltage divider resistor R2, the anti-reverse diode D1, the current limiting resistor R1, and the battery pack BDU positive relay S1. This enables the BMS to monitor the high-voltage status of the battery pack module PAKE in real time. By analyzing the voltage signal acquired by the ADC detection port HV_ADC, it detects and determines the operating status of the battery pack module PAKE and the connection status of the battery pack negative electrode relay S3. It does not rely on other detection circuit resources, using a single ADC to directly detect the negative electrode voltage of the battery pack module PAKE, freeing up significant hardware resources and isolation devices. Furthermore, this optimized circuit design reduces costs while improving the accuracy and reliability of the sampling signal. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the low-cost BMS high-voltage negative electrode sampling circuit of this utility model.

[0019] The attached diagram is labeled as follows: 1. Battery pack module PAKE; 2. Safety switch SA; 3. Voltage divider resistor R3; 4. ADC detection port HV_ADC; 5. Voltage divider resistor R2; 6. Anti-reverse diode D1; 7. Current limiting resistor R1; 8. High voltage ground HV_GND; 9. Battery pack negative relay S3; 10. Battery pack BDU positive relay S1; 11. Battery pack BDU precharge relay S2. Detailed Implementation

[0020] The technical solution of this utility model will be described in detail below through specific embodiments.

[0021] Reference Figure 1 As shown, this utility model discloses a low-cost BMS high-voltage negative sampling circuit structure, including a battery pack module PAKE1, a safety switch SA2, a voltage divider resistor R33, an ADC detection port HV_ADC4, a voltage divider resistor R25, an anti-reverse diode D16, a current limiting resistor R17, a high-voltage ground terminal HV_GND8, a battery pack negative relay S39, a battery pack BDU positive relay S110, and a battery pack BDU pre-charge relay S211. The positive terminal to the negative terminal of the battery pack module PAKE1 are connected in series with the safety switch SA2, the voltage divider resistor R33, the voltage divider resistor R25, the anti-reverse diode D16, and the battery pack negative relay S39.

[0022] The topology between voltage divider resistors R33 and R25 is connected to the ADC detection port HV_ADC4.

[0023] The current-limiting resistor R17 is connected in a topology between the voltage divider resistor R25 and the anti-reverse diode D16, and the other end of the current-limiting resistor R17 is connected in series with the high voltage ground terminal HV_GND8.

[0024] At the node between battery pack module PAKE1 and safety switch SA2, a battery pack BDU positive relay S110 is connected in series. A battery pack BDU pre-charge relay S211 is connected in parallel across the two ends of the battery pack BDU positive relay S110. The battery pack BDU pre-charge relay S211 is used to pre-charge the battery pack before the battery pack BDU positive relay S110 closes, preventing current surges caused by direct high voltage connection. Battery pack module PAKE1 provides power output, and safety switch SA2 protects the battery pack and circuitry from overcurrent or other abnormal conditions. Voltage divider resistor R33... The voltage divider resistor R25 is used in the voltage divider circuit to reduce the high voltage potential to suit the detection range of the ADC. The ADC detection port HV_ADC4 is used to acquire the voltage signal after voltage division, convert the analog signal into a digital signal and supply it to the BMS for processing. The high voltage ground terminal HV_GND8 is used to provide the circuit's reference ground. The battery pack negative relay S39 is used to control the connection and disconnection of the battery pack negative terminal. The battery pack BDU positive relay S110 is used to control the connection and disconnection of the battery pack positive terminal. The battery pack BDU precharge relay S211 is used in the precharge process to prevent current surges caused by direct connection to high voltage.

[0025] Preferably, the high voltage output by the battery pack module PAKE1 is divided by voltage divider resistors R33 and R25, so that the ADC detection port HV_ADC4 detects a voltage signal that has decreased at the node between voltage divider resistors R33 and R25, that is, the ADC detection port HV_ADC4 samples it.

[0026] Preferably, the current-limiting resistor R17 limits the current through the ADC detection port HV_ADC4, thereby limiting the current and protecting the ADC circuit from excessive current. The reverse protection diode D16 prevents current from flowing in the opposite direction, thereby protecting the circuit components from damage. The battery pack negative relay S39 controls the connection and disconnection of the negative terminal of the battery pack module PAKE1. The battery pack BDU positive relay S110 and the battery pack BDU precharge relay S211 control the connection and disconnection of the positive terminal of the battery pack module PAKE1.

[0027] Preferably, the voltage value detected by the ADC detection port HV_ADC4 is affected by the connection and disconnection of the battery pack BDU positive relay S110, the battery pack BDU precharge relay S211, and the battery pack negative relay S39. When the battery pack negative relay S39 and the battery pack BDU positive relay S110 are in the disconnected state, the formula for calculating the voltage value detected by the ADC detection port HV_ADC4 is as follows: In the formula, U ADC This represents the voltage value acquired by the ADC detection port HV_ADC4, U PAKE This represents the voltage value acquired directly by the battery pack module PAKE1 using a standard ADC acquisition method. R1, R2, and R3 represent the resistance values ​​of the voltage divider resistor R33, the voltage divider resistor R25, and the current limiting resistor R17, respectively. The voltage divider resistor R33, the voltage divider resistor R25, and the current limiting resistor R17 are used for voltage division.

[0028] When the battery pack negative relay S39 and the battery pack BDU positive relay S110 are in the closed state, the formula for calculating the voltage value detected by the ADC detection port HV_ADC4 is as follows: In the formula, U ADC This represents the voltage value acquired by the ADC detection port HV_ADC4, U PAKE This represents the voltage value acquired directly by the battery pack module PAKE1 using a standard ADC acquisition method. R1 and R2 represent the resistance values ​​of voltage divider resistors R33 and R25, respectively, and these resistors are used for voltage division. Furthermore, through two different voltage division methods, U... PAKE The total voltage of the battery pack module PAKE1 and the voltage value U collected by the ADC detection port HV_ADC4 are also included. ADC The comparison is performed to determine whether the relay status is stuck.

[0029] Preferably, the battery pack BDU positive relay S110 is model GIGAVACGX14, with a rated voltage of 300V and a rated current of 200A, to control the high-voltage positive circuit output; the battery pack BDU precharge relay S211 is model OmronG8P-1A4P, with a rated voltage of 300V and a rated current of 30A, to control the high-voltage precharge circuit output; and the battery pack negative relay S39 is model TycoEV200AAANA, with a rated voltage of 300V DC and a rated current of 200A, to control the high-voltage negative circuit output.

[0030] Preferably, the voltage divider resistor R33 has a resistance of 990KΩ and an accuracy of 0.1%, and the voltage divider resistor R25 has a resistance of 10KΩ and an accuracy of 0.1%, to ensure the accuracy and stability of the voltage division ratio. The battery pack module PAKE1 has a resistance range of 1-10KΩ and an accuracy of 1%, to ensure the reliability of the current limiting.

[0031] Working principle: When the battery pack module PAKE1 provides voltage, the safety switch SA2 is closed. Through the voltage divider resistors R33 and R25, the high voltage is divided to a level suitable for ADC detection. This voltage signal is acquired through the ADC detection port HV_ADC4. The analog signal acquired by the ADC detection port HV_ADC4 is converted into a digital signal and transmitted to the BMS for processing. By connecting or disconnecting the battery pack negative relay S39 or the battery pack BDU positive relay S110, the voltage value measured by the ADC detection port HV_ADC4 will be different. This allows for the detection and judgment of the working status of the battery pack module PAKE1, as well as the detection and judgment of the sticking status of the battery pack negative relay S39. In the circuit, the current limiting resistor R17 ensures that the current is not too large, protecting the ADC detection port HV_ADC4, and the reverse protection diode D16 ensures that the current does not flow in reverse, protecting the relay components in the circuit.

[0032] The above description is only a preferred embodiment of the present utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions, improvements, etc., made within the design concept of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A low-cost BMS high-voltage negative sampling circuit, characterized in that: The battery pack module PAKE (1), safety switch SA (2), voltage divider resistor R3 (3), ADC detection port HV_ADC (4), voltage divider resistor R2 (5), anti-reverse diode D1 (6), current limiting resistor R1 (7), high voltage ground HV_GND (8), battery pack negative relay S3 (9), battery pack BDU positive relay S1 (10), and battery pack BDU precharge relay S2 (11) are connected in series from the positive terminal to the negative terminal of the battery pack module PAKE (1). The voltage divider resistor R3 (3) and the voltage divider resistor R2 (5) are connected in a topology to the ADC detection port HV_ADC (4); The voltage divider resistor R2(5) and the anti-reverse diode D1(6) are connected in a topology to one end of the current limiting resistor R1(7), and the other end of the current limiting resistor R1(7) is connected in series with the high voltage ground terminal HV_GND(8). At the node between the battery pack module PAKE (1) and the safety switch SA (2), the battery pack BDU positive relay S1 (10) is connected in series in the topology, and the two ends of the battery pack BDU positive relay S1 (10) are connected in parallel with the battery pack BDU precharge relay S2 (11).

2. The low-cost BMS high-voltage negative sampling circuit according to claim 1, characterized in that: The high voltage output by the battery pack module PAKE(1) is divided by the voltage divider resistors R3(3) and R2(5), so that the ADC detection port HV_ADC(4) detects a voltage signal that is reduced at a node between the voltage divider resistors R3(3) and R2(5), that is, the ADC detection port HV_ADC(4) samples it.

3. The low-cost BMS high-voltage negative sampling circuit according to claim 2, characterized in that: The current-limiting resistor R1 (7) limits the current through the ADC detection port HV_ADC (4), the anti-reverse diode D1 (6) prevents the current from flowing in the opposite direction, the battery pack negative relay S3 (9) controls the connection and disconnection of the negative terminal of the battery pack module PAKE (1), and the battery pack BDU positive relay S1 (10) and the battery pack BDU precharge relay S2 (11) control the connection and disconnection of the positive terminal of the battery pack module PAKE (1).

4. The low-cost BMS high-voltage negative sampling circuit according to claim 3, characterized in that: The voltage value detected by the ADC detection port HV_ADC(4) is affected by the connection and disconnection of the battery pack BDU positive relay S1(10), battery pack BDU precharge relay S2(11), and battery pack negative relay S3(9). When the battery pack negative relay S3(9) and the battery pack BDU positive relay S1(10) are in the disconnected state, the calculation formula for the voltage value detected by the ADC detection port HV_ADC(4) is as follows: In the formula, U ADC U represents the voltage value acquired by the ADC detection port HV_ADC(4). PAKE The voltage value is represented by the battery pack module PAKE(1) directly acquired by the ordinary ADC acquisition method. R1, R2, and R3 represent the resistance values ​​of the voltage divider resistor R3(3), the voltage divider resistor R2(5), and the current limiting resistor R1(7), respectively. When the battery pack negative relay S3(9) and the battery pack BDU positive relay S1(10) are in the closed state, the formula for calculating the voltage value detected by the ADC detection port HV_ADC(4) is as follows: In the formula, U ADC U represents the voltage value acquired by the ADC detection port HV_ADC(4). PAKE R1 represents the voltage value directly acquired by the battery pack module PAKE(1) using a common ADC acquisition method, and R2 represents the resistance values ​​of the voltage divider resistors R3(3) and R2(5), respectively.

5. The low-cost BMS high-voltage negative sampling circuit according to claim 3, characterized in that: The battery pack BDU positive relay S1(10) is model GIGAVAC GX14, with a rated voltage of 300V and a rated current of 200A. The battery pack BDU precharge relay S2(11) is model Omron G8P-1A4P, with a rated voltage of 300V and a rated current of 30A. The battery pack negative relay S3(9) is model Tyco EV200AAANA, with a rated voltage of 300V DC and a rated current of 200A.

6. The low-cost BMS high-voltage negative sampling circuit according to claim 3, characterized in that: The voltage divider resistor R3(3) has a resistance of 990KΩ and an accuracy of 0.1%, the voltage divider resistor R2(5) has a resistance of 10KΩ and an accuracy of 0.1%, and the battery pack module PAKE(1) has a resistance range of 1-10KΩ and an accuracy of 1%.

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