Cathode relay detection circuit and battery management system

Abstract

The utility model discloses a cathode relay detection circuit and a battery management system, the cathode relay detection circuit comprises a power supply, a first resistor, a second resistor, a third resistor, a first transistor, a second transistor and a cathode relay; the first end of the first resistor is connected with the anode 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 cathode of the power supply, and a test point is arranged between the first resistor and the second resistor and used for detecting the abnormity of the cathode 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 anode end of the first transistor, and the cathode end of the first transistor is connected with the first end of the cathode relay; the anode end of the second transistor is connected with the second end of the second resistor, the cathode end of the second transistor is connected with the cathode end of the first transistor, and the second end of the cathode relay is connected with the cathode of the power supply.

Description

Technical Field

[0001] This application belongs to the field of circuit testing technology, specifically relating to a negative electrode relay detection circuit and a battery management system. Background Technology

[0002] As the new energy vehicle industry places higher demands on the safety, stability, and reliability of battery management systems (BMS), the accuracy of high-voltage circuit detection has become a core factor affecting the overall performance of the system, with condition diagnosis of key components such as relays being particularly important.

[0003] During the switching or circuit state transition between the battery pack and the negative relay, the time lag effect of charge redistribution due to the distributed capacitance of the vehicle body causes transient voltage disturbances in the negative relay. However, existing technical solutions generally suffer from the problem of failing to capture negative voltage fluctuations, resulting in the inability to identify negative voltage faults in the negative relay, thus affecting the system safety of the high-voltage battery. Utility Model Content

[0004] This application aims to provide a negative electrode relay detection circuit and a battery management system that can solve the problem of the inability to identify negative voltage faults in the negative electrode relay in the prior art.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, embodiments of this application propose a negative relay detection circuit, comprising: a negative relay detection circuit including: a power supply, a first resistor, a second resistor, a third resistor, a first transistor, a second transistor, and a negative relay; a first end of the first resistor is connected to the positive terminal of the power supply, a second end of the first resistor is connected to the first end of the second resistor, and a second end of the second resistor is connected to the negative terminal of the power supply; a test point is provided between the first resistor and the second resistor, the test point being used to detect abnormalities in the negative relay; a first end of the third resistor is connected to the test point, and a second end of the third resistor is connected to the positive terminal of the first transistor, the negative terminal of the first transistor being connected to the first end of the negative relay; the positive terminal of the second transistor is connected to the second end of the second resistor, the negative terminal of the second transistor is connected to the negative terminal of the first transistor, and the second end of the negative relay is connected to the negative terminal of the power supply.

[0007] Optionally, at least one of the first transistor and the second transistor is a clamping diode.

[0008] Optionally, when both the first transistor and the second transistor are clamping diodes, the difference between the clamping voltage of the first transistor and the clamping voltage of the second transistor is less than the voltage value of the power supply.

[0009] Optionally, the clamping voltage of the first transistor and the clamping voltage of the second transistor are equal.

[0010] Optionally, the ratio of the resistance value of the first resistor to the resistance value of the third resistor is B, satisfying: 1.7≤B≤33; and / or, the ratio of the resistance value of the first resistor to the resistance value of the second resistor is C, satisfying: 0.5≤C≤33.

[0011] Optionally, it further includes a fourth resistor; the first end of the fourth resistor is connected to the negative terminal of the first transistor, and the second end of the fourth resistor is connected to the first terminal of the negative relay.

[0012] Optionally, the fourth resistor includes a plurality of sub-resistors; the plurality of sub-resistors are connected in series to form a resistor string, the first end of the resistor string is electrically connected to the negative terminal of the first transistor, and the second end of the resistor string is connected to the first terminal of the negative relay.

[0013] Optionally, the resistance value of each of the sub-resistors is equal.

[0014] Optionally, it also includes a data acquisition device; the data acquisition device is electrically connected to the detection point, and the data acquisition device is used to detect the voltage of the detection point.

[0015] Secondly, this application provides a battery management system, including the negative electrode relay detection circuit, battery pack, and negative electrode sampling module described in the above embodiments; the negative electrode of the battery pack is connected to the second terminal of the negative electrode relay, and the positive electrode of the battery pack is connected to the first terminal of the negative electrode sampling module, and the second terminal of the negative electrode sampling module is connected to the first terminal of the negative electrode relay.

[0016] In the embodiments of this application, by connecting the first end of the first resistor to the positive terminal of the power supply, the second end of the first resistor to the first end of the second resistor, and the second end of the second resistor to the negative terminal of the power supply, a test point is provided between the first and second resistors to detect abnormalities in the negative relay; the first end of the third resistor is connected to the test point, the second end of the third resistor is connected to the positive terminal of the first transistor, and the negative terminal of the first transistor is connected to the first end of the negative relay; the positive terminal of the second transistor is connected to the second end of the second resistor, the negative terminal of the second transistor is connected to the negative terminal of the first transistor, and the second terminal of the negative relay is connected to the negative terminal of the power supply. This allows the negative terminal of the second transistor to be clamped to a suitable negative voltage value, the positive terminal of the first transistor to be clamped to a suitable voltage value, and, in conjunction with the power supply, ensures that the total voltage between the first and third resistors is within a suitable range. This ensures that the test point can always detect a suitable voltage signal, effectively identifying whether the negative relay has a negative voltage fault, thereby improving the system safety of the battery.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of a prior art negative relay detection circuit;

[0020] Figure 2 This is a schematic diagram of a negative relay detection circuit according to an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of another negative relay detection circuit according to an embodiment of this application;

[0022] Figure 4 This is a schematic diagram of the detection circuit of the battery management system according to an embodiment of this application.

[0023] Figure label:

[0024] 1-First resistor; 2-Second resistor; 3-Third resistor; 4-Fourth resistor; 41-Sub-resistor; 5-Negative relay; 6-Battery pack; 7-Test point; 8-First transistor; 9-Second transistor; 10-Power supply; 11-Negative sampling module; 12-Positive relay; 13-Third transistor. Detailed Implementation

[0025] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0026] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0027] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0028] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] Existing negative relay detection circuit, such as Figure 1As shown, the device includes a first resistor 1, a second resistor 2, a third resistor 3, a first transistor 8, and a third transistor 13. The first end of the first resistor 1 is connected to the positive terminal of the power supply 10. The second end of the first resistor 1 is connected to the first end of the second resistor 2. The second end of the second resistor 2 is connected to the positive terminal of the third transistor 13. The negative terminal of the third transistor 13 is connected to the negative terminal of the power supply 10. A test point 7 is provided between the first resistor 1 and the second resistor 2. The test point 7 is used to detect abnormalities in the negative relay 5. The second end of the third resistor 3 is connected to the test point 7. The first end of the third resistor 3 is connected to the positive terminal of the first transistor 8. The negative terminal of the first transistor 8 is connected to the negative relay 5. In the prior art, the function of the first transistor 8 and the second transistor 9 is solely to prevent reverse current flow.

[0030] As can be seen from the above, if a negative voltage occurs in the negative relay 5, for example, the negative voltage value of the negative relay 5 is -400V, and the value of the power supply 10 is 5V, since the first resistor 1 and the third resistor 3 are connected in series between the power supply 10 and the negative relay 5, according to the voltage division principle of the circuit, the third resistor 3 and the first resistor 1 will divide the voltage proportionally. The voltage value detected at the test point 7 is equal to the voltage division value of the third resistor 3. Since the total voltage between the power supply 10 and the negative relay 5 is negative, the detection point will always collect a negative voltage signal. Since the effective range of most existing acquisition chips is 0V to 5V, the negative voltage signal is outside the effective range of the chip. This makes the chip unable to correctly identify the negative voltage signal, and thus unable to effectively identify the negative voltage fault, thereby affecting the system safety of the high-voltage battery.

[0031] The negative electrode relay detection circuit and battery management system provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0032] like Figure 2 As shown in the figure, this application embodiment proposes a negative relay detection circuit, including: 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 relay 5; the first end of the first resistor 1 is connected to the positive terminal of the power supply 10, the second end of the first resistor 1 is connected to the first end of the second resistor 2, the second end of the second resistor 2 is connected to the negative terminal of the power supply 10, a test point 7 is provided between the first resistor 1 and the second resistor 2, the test point 7 is used to detect abnormalities in the negative relay 5; the first end of the third resistor 3 is connected to the test point 7, the second end of the third resistor 3 is connected to the positive terminal of the first transistor 8, the negative terminal of the first transistor 8 is connected to the first end of the negative relay 5; the positive terminal of the second transistor 9 is connected to the second end of the second resistor 2, the negative terminal of the second transistor 9 is connected to the negative terminal of the first transistor 8, and the second end of the negative relay 5 is connected to the negative terminal of the power supply.

[0033] In the embodiments of this application, by connecting the first end of the first resistor 1 to the positive terminal of the power supply 10, the second end of the first resistor 1 to the first end of the second resistor 2, and the second end of the second resistor 2 to the negative terminal of the power supply 10, a test point 7 is provided between the first resistor 1 and the second resistor 2. The test point 7 is used to detect abnormalities in the negative relay 5. The first end of the third resistor 3 is connected to the test point 7, the second end of the third resistor 3 is connected to the positive terminal of the first transistor 8, and the negative terminal of the first transistor 8 is connected to the first end of the negative relay 5. The positive terminal of the third resistor 3 is connected to the second end of the second resistor 2, the negative terminal of the second transistor 9 is connected to the negative terminal of the first transistor 8, and the second end of the negative relay 5 is connected to the negative terminal of the power supply. In this way, the negative terminal of the second transistor 9 is clamped to a suitable negative voltage value, the positive terminal of the first transistor 8 is clamped to a suitable voltage value, and in conjunction with the power supply 10, the total voltage value between the first resistor 1 and the third resistor 3 is within a suitable range. This ensures that the test point 7 can always detect a suitable voltage signal, thereby effectively identifying whether the negative relay 5 has a negative voltage fault, thus improving the system safety of the battery.

[0034] The technical solution of this application can not only identify whether the negative relay 5 has a negative voltage fault, but also diagnose faults such as the negative relay 5 being open-circuited. The diagnostic principle of the negative relay 5 being open-circuited and closed is as follows: If the negative relay 5 is closed, the current of the power supply 10 flows through the first resistor 1, the second resistor 2, and the third resistor 3. At this time, the second resistor 2 and the third resistor 3 are connected in parallel and then in parallel with the first resistor 1. The test point 7 collects the voltage after the second resistor 2 and the third resistor 3 are connected in parallel. In this way, the test point 7 can detect the voltage within a fixed range. The negative relay 5 can be judged by the voltage value. If the negative relay 5 is open, the current of the power supply 10 flows through the first resistor 1 and the second resistor 2, but does not flow through the third resistor 3. The test point 7 can collect the voltage within another fixed range. The negative relay 5 can be judged by the voltage value.

[0035] It should be noted that the function of power supply 10 is to provide a stable reference voltage when the battery voltage fluctuates or becomes disordered.

[0036] Optionally, such as Figure 2 As shown, at least one of the first transistor 8 and the second transistor 9 is a clamping diode.

[0037] In this embodiment, at least one of the first transistor 8 and the second transistor 9 is configured as a clamping diode. This allows the clamping characteristics of the clamping diode to clamp its own voltage to a specific value, thereby maintaining the total voltage between the power supply 10 and the first transistor 8 within a suitable range, thus providing a test basis for test point 7.

[0038] Specifically, the principle of a clamping diode is as follows: A clamping diode has unidirectional conductivity, which means that when the voltage at the negative terminal of the clamping diode is greater than the voltage at the positive terminal, the diode is cut off; and when the voltage at the positive terminal is greater than the voltage at the negative terminal and conduction occurs, the voltage across the clamping diode is limited to its diode voltage drop.

[0039] It should be noted that the clamping diode can be a general-purpose diode, a bidirectional trigger diode, a fast recovery diode, a Schottky diode, a Zener diode, or a transient suppression diode, etc. Those skilled in the art can choose according to actual needs, and the embodiments of this application are not limited herein.

[0040] Optionally, such as Figure 2 As shown, when both the first transistor 8 and the second transistor 9 are clamping diodes, the difference between the clamping voltage of the first transistor 8 and the clamping voltage of the second transistor 9 is less than the voltage value of the power supply 10.

[0041] In this embodiment, when both the first transistor 8 and the second transistor 9 are clamping diodes, the difference between the clamping voltage of the first transistor 8 and the clamping voltage of the second transistor 9 is set to be less than the voltage value of the power supply 10. This ensures that the total voltage between the positive terminal of the first transistor 8 and the positive terminal of the power supply 10 is positive.

[0042] It is understandable that when the clamping diode is a silicon diode, the voltage drop across the silicon diode is 0.7V. The positive terminal of the second transistor 9 in this application is connected to the negative terminal of the power supply 10, which is equivalent to the positive terminal of the second transistor 9 being grounded. Therefore, the voltage at the negative terminal of the second transistor 9 is 0V-0.7V=-0.7V, that is, the voltage at the positive terminal of the second transistor 9 is 0V and the voltage at the negative terminal is -0.7V.

[0043] In some embodiments, the voltage of power supply 10 is generally set to 5V, the clamping voltage of the first transistor 8 is 0.7V, and the clamping voltage of the second transistor 9 is 3.5V. Since the positive terminal of the second transistor 9 is grounded, the negative terminal of the second transistor 9 is clamped to -3.5V. Since the negative terminal of the second transistor 9 is connected to the negative terminal of the first transistor 8, the voltage of the negative terminal of the first transistor 8 is equal to the voltage of the negative terminal of the second transistor 9. The voltage of the positive terminal of the first transistor 8 is -2.8V. The voltage between the positive terminal of the first transistor 8 and power supply 10 is -2.8V + 5V = 2.2V. Therefore, a positive voltage signal can always be detected at test point 7, thereby effectively identifying whether the negative relay 5 has a negative voltage fault and improving the system safety of the battery.

[0044] In some embodiments, the clamping voltage of the first transistor 8 and the clamping voltage of the second transistor 9 are set in the range of 0.7V to 1.4V. This ensures that the clamping voltage of the first transistor 8 and the clamping voltage of the second transistor 9 are within the clamping voltage range of a general-purpose diode, thereby replacing a dedicated voltage detection integrated circuit (IC), i.e., reducing material costs while maintaining the same detection accuracy.

[0045] Optionally, such as Figure 2 As shown, the clamping voltage of the first transistor 8 is equal to the clamping voltage of the second transistor 9.

[0046] In this embodiment, the clamping voltage of the first transistor 8 and the clamping voltage of the second transistor 9 are set to be equal. This ensures that the first transistor 8 and the second transistor 9 enter the clamping state under the same voltage conditions, avoiding signal amplitude fluctuations caused by different clamping voltages, thereby guaranteeing the stability of the entire circuit operation.

[0047] In some embodiments, the clamping voltage of the first transistor 8 can be set to 0.7V, and the clamping voltage of the second transistor 9 can also be set to 0.7V; of course, the clamping voltage of the first transistor 8 can be set to 1.4V, and the clamping voltage of the second transistor 9 can be set to 0.7V.

[0048] Optionally, the ratio of the resistance value of the first resistor 1 to the resistance value of the third resistor 3 is B, which satisfies: 1.7≤B≤33.

[0049] In this embodiment, the ratio B between the resistance values ​​of the first resistor 1 and the third resistor 3 is set within a certain range. By reasonably setting the resistance values ​​B of the first resistor 1 and the third resistor 3, the voltage division ratio of the circuit can be optimized, making the voltage change at test point 7 more sensitive to abnormal conditions of the negative relay 5, thereby improving the detection accuracy. Furthermore, when B is within this range, the voltage change at test point 7 caused by an abnormality in the negative relay 5 can be amplified to the maximum extent while ensuring normal circuit operation, facilitating a more accurate identification of whether the negative relay 5 has a negative voltage fault.

[0050] For example, the value of B can be set to any number of 5, 6, 7, 8, 9, 10 and any range between any two numbers.

[0051] For example, the resistance value of the first resistor 1 can be set to one megohm, and the resistance value of the third resistor 3 can be set to one hundred kilohms.

[0052] In some embodiments, based on Figure 4 The circuit structure shown was tested using non-standard first resistor 1 and third resistor 3. The power supply was 5V, the resistance of second resistor 2 was 2000kΩ, and a -400V voltage was applied to the first terminal of the negative relay. The clamping voltage of first transistor 8 was the same as that of second transistor 9. A data acquisition chip with a range of 0V-5V was then used to detect the voltage at test point 7. The detection results are shown in Table 1 below.

[0053] Table 1: Test results for test point 7 at different ratios B

[0054]

[0055] It should be noted that the negative relay detection circuit also includes a voltage judgment chip, which is electrically connected to the acquisition chip. The effective range of the voltage judgment chip is 0V-1.5V. The voltage judgment chip can determine whether the negative relay 5 has a negative voltage fault based on the acquisition voltage of the acquisition chip (i.e., the detection voltage at test point 7). If the detection voltage at test point 7 is within the range of 0V-1.5V, then the negative relay 5 is determined to have a negative voltage fault; if the detection voltage at test point 7 is not within the range of 0V-1.5V, then the negative relay 5 is determined not to have a negative voltage fault.

[0056] As can be seen from the above embodiments, as shown in Embodiment 1, when the ratio B is less than 1.7, the detection voltage at test point 7 is 3.5V, which exceeds the effective range of the voltage judgment chip, and the voltage judgment chip determines that the negative relay 5 has not experienced a negative voltage fault; as shown in Embodiment 5, when the ratio B is greater than 33, the detection voltage at test point 7 is negative, which exceeds the effective range of the voltage judgment chip, and the voltage judgment chip determines that the negative relay 5 has not experienced a negative voltage fault; as shown in Embodiments 2 to 4, when the ratio B is between 1.7 and 33, the detection voltage at test point 7 is between 0V and 1.5V, which is within the effective range of the voltage judgment chip, and the voltage judgment chip determines that the negative relay 5 has experienced a negative voltage fault.

[0057] Optionally, the ratio of the resistance value of the first resistor 1 to the resistance value of the second resistor 2 is C, which satisfies: 0.5≤C≤33.

[0058] In this embodiment, the ratio C between the resistance values ​​of the first resistor 1 and the second resistor 2 is kept within a certain range. This allows test point 7 to optimize the voltage division ratio of the circuit based on the ratio C between the resistance values ​​of the first resistor 1 and the second resistor 2, making the voltage change at test point 7 more sensitive to abnormal conditions of the negative relay 5, thereby improving the detection accuracy.

[0059] For example, the ratio C between the resistance value of the first resistor 1 and the resistance value of the second resistor 2 is 1. In this way, the voltages obtained by the first resistor 1 and the second resistor 2 are the same, that is, the voltage detected by the test point 7 is about 2.5V. When the voltage detected by the test point 7 is about 2.5V, it can be determined that the negative relay 5 is disconnected.

[0060] For example, the value of C can be set to any value among 0.5, 0.6, 0.7, 0.8, 0.9, and 1, as well as any range between any two values.

[0061] In some embodiments, based on Figure 4 The circuit structure shown was tested using non-standard first resistor 1 and second resistor 2. The power supply was 5V. The resistance of the third resistor 3 was 600kΩ. A -400V voltage was applied to the first terminal of the negative relay. The clamping voltage of the first transistor 8 was the same as that of the second transistor 9. A data acquisition chip with a range of 0-5V was used to detect the voltage at test point 7. The detection results are shown in Table 2 below.

[0062] Table 2: Test results for test point 7 at different ratios C

[0063]

[0064] As can be seen from the above embodiments, as shown in Embodiment 6, when the ratio C is less than 0.5, the detection voltage at test point 7 is 1.6V, which exceeds the effective range of the voltage judgment chip, and the voltage judgment chip determines that the negative relay 5 has not experienced a negative voltage fault; as shown in Embodiments 10 and 11, when the ratio C is greater than 33, the detection voltage at test point 7 is negative, which exceeds the effective range of the voltage judgment chip, and the voltage judgment chip determines that the negative relay 5 has not experienced a negative voltage fault; as shown in Embodiments 7 to 9, when the ratio B is between 0.5 and 33, the detection voltage at test point 7 is between 0V and 1.5V, which is within the effective range of the voltage judgment chip, and the voltage judgment chip determines that the negative relay 5 has experienced a negative voltage fault.

[0065] Optionally, such as Figure 2 and Figure 3 As shown, it also includes a fourth resistor 4; the first end of the fourth resistor 4 is connected to the negative terminal of the first transistor 8, and the second end of the fourth resistor 4 is connected to the first end of the negative relay 5.

[0066] In this embodiment, the first end of the fourth resistor 4 is connected to the negative terminal of the first transistor 8, and the second end of the fourth resistor 4 is connected to the first end of the negative relay 5. Thus, when an abnormal situation occurs in the circuit, such as excessive current, the fourth resistor 4 can limit the current flowing to the negative terminal of the first transistor 8, preventing excessive current from damaging components such as the first transistor 8, thereby improving the reliability and stability of the circuit.

[0067] Furthermore, in some complex electromagnetic environments, the circuit may be affected by various interference signals. The fourth resistor 4 can be combined with other components to form part of a filter circuit or other anti-interference circuit structure to attenuate or suppress interference signals, reduce the impact of interference signals on the normal operation of the circuit, improve the anti-interference capability of the circuit, and enable the detection circuit to more accurately detect the state of the negative relay 5, avoiding misjudgments caused by interference.

[0068] Optionally, such as Figure 3 As shown, the fourth resistor 4 includes multiple sub-resistors 41; the multiple sub-resistors 41 are connected in series to form a resistor string, the first end of the resistor string is electrically connected to the negative terminal of the first transistor 8, and the second end of the resistor string is electrically connected to the first end of the negative relay 5.

[0069] In this embodiment, multiple sub-resistors 41 are connected in series to form a resistor string. The first end of the resistor string is electrically connected to the negative terminal of the first transistor 8, and the second end of the resistor string is connected to the first terminal of the negative relay 5. This allows for flexible selection of the resistance value and number of sub-resistors 41 according to specific circuit design requirements, thereby accurately achieving the desired total resistance value. For example, by adjusting the combination of sub-resistors 41, the resistance value can be precisely adjusted to a suitable range to ensure that the voltage at test point 7 accurately reflects the operating state of the negative relay 5.

[0070] Furthermore, the stability requirements for resistance values ​​vary depending on the operating environment, such as different temperatures and humidity levels. Connecting multiple sub-resistors 41 in series allows for convenient adjustment of resistance values ​​to adapt to different operating conditions. For example, in high-temperature environments, the resistance values ​​of some resistors may change. By adjusting the combination of sub-resistors 41, this resistance change can be compensated for, ensuring circuit stability and detection accuracy.

[0071] Optionally, the resistance value of each sub-resistor 41 is equal.

[0072] In this embodiment, the resistance value of each sub-resistor 41 is set to be equal. This makes it easier to ensure consistency of sub-resistors 41 with the same resistance value during production, and the performance parameters of each sub-resistor 41 are closer, thus making the performance of the entire resistor string more stable and reliable.

[0073] For example, there may be four sub-resistors 41, and the resistance value of each sub-resistor 41 may be set to 100 kiloohms. Those skilled in the art can choose according to actual needs, and the embodiments of this application are not limited here.

[0074] In some embodiments, the resistance values ​​of each sub-resistor 41 may also be set to be unequal. Those skilled in the art can choose according to actual needs, and the embodiments of this application do not impose any limitations here.

[0075] Optionally, such as Figure 2 and Figure 3 As shown, it also includes a data acquisition unit; the data acquisition unit is electrically connected to the detection point and is used to detect the voltage of the detection point.

[0076] In this embodiment, by electrically connecting the acquisition unit to the detection point, the acquisition unit detects the voltage at the detection point. This allows the acquisition unit to obtain the voltage value at the detection point in real time and accurately. Through precise detection of this voltage, abnormal conditions such as negative voltage faults in the negative relay 5 can be detected promptly. For example, when a fault in the negative relay 5 causes the voltage at the detection point to deviate from the normal range, the acquisition unit can quickly detect this change, providing a reliable basis for subsequent fault diagnosis and handling, greatly improving the accuracy and timeliness of fault detection.

[0077] Furthermore, the collected voltage data from the detection points can be transmitted to the control unit (such as a microprocessor) for further analysis and processing. The control unit can judge and make decisions based on preset thresholds and algorithms, achieving intelligent monitoring and management of the negative relay's state. For example, when an abnormal voltage is detected, the control unit can automatically trigger an alarm mechanism to remind the user to check and maintain the device, or take corresponding protective measures to prevent further escalation of the fault, thus improving the intelligence and reliability of the battery management system.

[0078] Optionally, such as Figure 2 and Figure 3 As shown, the acquisition device is set as an acquisition chip, and the effective range of the acquisition chip is D, which satisfies: 0V<D≤5V.

[0079] In the embodiments of this application, many common electronic components and systems have a power supply voltage and signal transmission range mostly between 0V and 5V. This application sets the effective range D of the acquisition chip between 0V and 5V. This facilitates adaptation to these components and systems, eliminating the need to design additional complex level conversion circuits and reducing the complexity and cost of circuit design.

[0080] For example, the input and output signals of a microcontroller are typically in the range of 0V-5V, and the voltage signal output by the acquisition chip can be directly read and processed by the microcontroller.

[0081] Optionally, such as Figure 4 As shown in the figure, this application embodiment proposes a battery management system, including the negative electrode relay detection circuit, battery pack 6 and negative electrode sampling module 11 in the above embodiment; the negative electrode of battery pack 6 is connected to the negative electrode of power supply 10, the positive electrode of battery pack 6 is connected to the first end of negative electrode sampling module 11, and the second end of negative electrode sampling module 11 is connected to the first end of negative electrode relay 5.

[0082] In the embodiments of this application, the negative terminal of the battery pack 6 is connected to the negative terminal of the power supply 10, the positive terminal of the battery pack 6 is connected to the first terminal of the negative terminal sampling module 11, and the second terminal of the negative terminal sampling module 11 is connected to the first terminal of the negative terminal relay 5. This allows the negative terminal sampling module 11 to collect electrical parameters of the battery pack 6 in the negative terminal circuit, such as voltage and current. Combined with information from the negative terminal relay detection circuit, key information such as the charging / discharging state and remaining capacity of the battery pack 6 can be accurately understood, providing data support for the effective management and protection of the battery.

[0083] In some embodiments, a battery management system further includes a positive relay 12, with its first terminal connected to the positive terminal of the battery pack 6 and its second terminal connected to the first terminal of the negative sampling module 11. Thus, by controlling the closing and opening of the positive relay 12, the circuit connection between the battery pack 6 and the negative sampling module 11 can be easily connected or disconnected. When the battery pack 6 needs to be charged or discharged, the positive relay 12 is closed to allow current to flow normally; when the system detects an abnormality (such as overcharge, over-discharge, short circuit, etc.) or needs maintenance, the positive relay 12 is opened to quickly disconnect the circuit, preventing danger or damage to the equipment.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A negative relay detection circuit, characterized in that, include: Power supply (10), first resistor (1), second resistor (2), third resistor (3), first transistor (8), second transistor (9) and negative relay (5); The first end of the first resistor (1) is connected to the positive terminal of the power supply (10), the second end of the first resistor (1) is connected to the first end of the second resistor (2), the second end of the second resistor (2) is connected to the negative terminal of the power supply (10), and a test point (7) is provided between the first resistor (1) and the second resistor (2). The test point (7) is used to detect the abnormality of the negative relay (5). The first end of the third resistor (3) is connected to the test point (7), the second end of the third resistor (3) is connected to the positive terminal of the first transistor (8), and the negative terminal of the first transistor (8) is connected to the first end of the negative relay (5). The positive terminal of the second transistor (9) is connected to the second terminal of the second resistor (2), the negative terminal of the second transistor (9) is connected to the negative terminal of the first transistor (8), and the second terminal of the negative relay (5) is connected to the negative terminal of the power supply (10).

2. The negative relay detection circuit according to claim 1, characterized in that, At least one of the first transistor (8) and the second transistor (9) is a clamping diode.

3. The negative relay detection circuit according to claim 2, characterized in that, When both the first transistor (8) and the second transistor (9) are clamping diodes, the difference between the clamping voltage of the first transistor (8) and the clamping voltage of the second transistor (9) is less than the voltage value of the power supply (10).

4. The negative relay detection circuit according to claim 3, characterized in that, The clamping voltage of the first transistor (8) is equal to the clamping voltage of the second transistor (9).

5. The negative relay detection circuit according to claim 1, characterized in that, The ratio between the resistance value of the first resistor (1) and the resistance value of the third resistor (3) is B, which satisfies: 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, which satisfies: 0.5≤C≤33.

6. The negative relay detection circuit according to claim 1, characterized in that, It also includes a fourth resistor (4); the first end of the fourth resistor (4) is connected to the negative terminal of the first transistor (8), and the second end of the fourth resistor (4) is connected to the first end of the negative relay (5).

7. The negative relay detection circuit according to claim 6, characterized in that, The fourth resistor (4) includes multiple sub-resistors (41); Multiple sub-resistors (41) are connected in series to form a resistor string. The first end of the resistor string is connected to the negative terminal of the first transistor (8), and the second end of the resistor string is connected to the first end of the negative relay (5).

8. The negative relay detection circuit according to claim 7, characterized in that, The resistance value of each of the sub-resistors (41) is equal.

9. The negative relay detection circuit according to claim 1, characterized in that, It also includes a data acquisition device; the data acquisition device is electrically connected to the detection point (7), and the data acquisition device is used to detect the voltage of the detection point (7).

10. A battery management system, characterized in that, include: The negative electrode relay detection circuit, battery pack (6), and negative electrode sampling module (11) according to any one of claims 1-9; The negative terminal of the battery pack (6) is connected to the second terminal of the negative relay (5), the positive terminal of the battery pack (6) is connected to the first terminal of the negative sampling module (11), and the second terminal of the negative sampling module (11) is connected to the first terminal of the negative relay (5).

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