Relay adhesion detection circuit and battery management system

Abstract

The utility model relates to a relay adhesion detection circuit and a battery management system, which are used for detecting a first relay to be detected, one end of the first relay is used for being connected with a battery module, and the other end of the first relay is used for being connected with a high-voltage power supply. The detection circuit comprises a detection power supply and a detection resistor which are connected in series with the first relay, and a voltage acquisition circuit which is connected in parallel with the detection resistor, and the target voltage values at the two ends of the detection resistor are acquired through the voltage acquisition circuit, so that adhesion detection of the first relay is realized. The detection circuit is simple in structure, low in cost and easy to implement. The circuit connection is simple, and the relay adhesion detection efficiency can be improved while the cost of the relay adhesion detection circuit and the battery management system is reduced.

Description

Technical Field

[0001] This application relates to the technical field of relay adhesion detection, and particularly to a relay adhesion detection circuit and a battery management system. Background Art

[0002] In new energy vehicles, relays control their states according to the instructions of the battery management system. When in use, due to interference, contamination, damage or faults, relays may exhibit the phenomenon of being unable to separate properly during operation, which is called relay adhesion.

[0003] Relay adhesion is one of the main reasons for relay failure. To improve the working stability of relays and enhance the safety of vehicles, it is necessary to detect relay adhesion. However, traditional relay adhesion detection circuits are complex and costly. Utility Model Content

[0004] Based on this, it is necessary to provide a relay adhesion detection circuit and a battery management system with a simple circuit and low cost.

[0005] In a first aspect, this application provides a relay adhesion detection circuit, including:

[0006] A detection power supply, connected in series with a first relay to be detected;

[0007] A detection resistor, connected in series with the detection power supply and the first relay respectively;

[0008] A voltage acquisition circuit, connected in parallel with the detection resistor, for acquiring the target voltage value of the detection resistor to determine whether the first relay is adhered according to the target voltage value; where:

[0009] One end of the first relay is used to connect to a battery module, and the other end is used to connect to a high-voltage power supply; the detection power supply, the detection resistor and the first relay form a detection loop.

[0010] In one embodiment, the detection power supply is a low-voltage power supply.

[0011] In one embodiment, the detection power supply includes a 12V power supply or a 24V power supply.

[0012] In one embodiment, the first relay includes one or more of a main negative relay, a main positive relay, a pre-charge relay, a fast charge relay and a heating relay.

[0013] In one embodiment, the detection resistor includes a resistor with a resistance value range of 1kΩ - 100kΩ.

[0014] In a second aspect, the present application provides a battery management system, including the relay adhesion detection circuit as described above. The battery management system further includes an MCU module, which is connected to the first relay and is used to control the opening or closing of the first relay.

[0015] In one embodiment, the MCU module is further connected to the detection circuit and is used to receive the target voltage value collected by the detection circuit, so as to determine whether the first relay is adhered according to the target voltage value and the state of the first relay.

[0016] In one embodiment, the detection power supply is connected to the battery management system and is used to supply power to the battery management system.

[0017] In one embodiment, the first relay is a main positive and negative relay.

[0018] In one embodiment, the battery management system is further connected to a second relay and is used to control the opening or closing of the second relay; wherein: the second relay is one or more of a main positive relay, a pre-charge relay, a fast charge relay, and a heating relay.

[0019] The above relay adhesion detection circuit and battery management system are used to realize the detection of the first relay to be detected. One end of the first relay is used to be connected to the battery module, and the other end is used to be connected to the high-voltage power supply. The detection circuit provided by the present application includes a detection power supply and a detection resistor connected in series with the first relay, and a voltage acquisition circuit connected in parallel with the detection resistor. The adhesion detection of the first relay is realized through the target voltage value of the detection resistor collected by the voltage acquisition circuit. The detection circuit of the present application has a simple structure, low cost and is easy to implement. The circuit connection of the present application is simple. While reducing the cost of the relay adhesion detection circuit and the battery management system, it can also improve the detection efficiency of relay adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 It is a circuit connection schematic diagram of a relay adhesion detection circuit in an embodiment;

[0022] Figure 2 It is a connection schematic diagram of a battery management system in an embodiment;

[0023] Figure 3Schematic connection diagram of a battery management system according to another embodiment;

[0024] Figure 4 Schematic connection diagram of a battery management system according to another embodiment;

[0025] Figure 5 Schematic connection diagram of a battery management system according to another embodiment.

[0026] Description of reference numerals:

[0027] 100, first relay; 210, detection power supply; 220, detection resistor; 230, voltage acquisition circuit; 310, MCU module; 400, second relay; 510, pre-charge relay; 520, pre-charge resistor. Detailed implementation manners

[0028] To make the above objects, features, and advantages of the present application more apparent and understandable, the following describes the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0029] In the description of the present application, it should be understood that if there appear these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present application.

[0030] In addition, if there appear these terms "first", "second", these terms are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one of such features. In the description of the present application, if there appears the term "plurality", the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0031] In this application, unless otherwise clearly specified and defined, if terms such as "installed", "connected", "linked", "fixed", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In this application, unless otherwise clearly specified and defined, if there is a description such as a first feature being "on" or "under" a second feature, its meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher horizontal level than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower horizontal level than the second feature.

[0033] It should be noted that if an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0034] First, a brief description is given to the application scenarios involved in the present utility model. In new energy vehicles, the vehicle power is provided by a battery. The battery pack PACK represents a lithium-ion battery pack, which is a common energy supply device in new energy batteries. PACK can be understood as a product formed by combining devices such as battery cells, connection sheets, protection boards, relays, etc. through the battery PACK process and forming a specific shape according to preset requirements.

[0035] With the rapid development of new energy vehicle technology, the use of lithium batteries is increasing, and the failure judgment of the internal relay of PACK is becoming more and more important. Relay adhesion is one of the main reasons for relay failure. The reasons for relay adhesion can be electrical interference, mechanical vibration, capacitive effect, relay aging, overloading of the relay, such as excessive load current, poor internal contact of the relay, loose or poor contact of the relay contact spring, the relay has not been used for a long time, or the working environment of the relay is harsh, such as extreme ambient temperature, etc.

[0036] In view of the above problems, the present utility model provides a relay adhesion detection circuit with a simple structure and low cost. As Figure 1 shown, a relay adhesion detection circuit according to an embodiment is used to detect a first relay 100 to be detected. The detection circuit includes a detection power supply 210 and a detection resistor 220 connected in series with the first relay 100; it also includes a voltage acquisition circuit 230 connected in parallel with the detection resistor 220. The voltage acquisition circuit 230 is used to acquire the target voltage value of the detection resistor 220 to determine whether the first relay 100 is adhered according to the target voltage value. One end of the first relay 100 is used to connect to a battery module, and the other end is used to connect to a high-voltage power supply; the detection power supply 210, the detection resistor 220 and the first relay 100 form a detection loop.

[0037] In this embodiment, the detection power supply 210 and the detection resistor 220 are set to form a detection loop with the first relay 100, and the voltage acquisition circuit 230 is connected in parallel on the detection resistor 220. The target voltage value of the detection resistor 220 is acquired through the voltage acquisition circuit 230 to realize the adhesion detection of the first relay 100. The relay adhesion detection circuit of this embodiment has a simple structure and is easy to implement. By using this relay adhesion detection circuit to detect the adhesion of the relay in the battery pack PACK, there is no need to additionally set up a circuit and data acquisition on the load, and the adhesion detection of the relay can be realized only by acquiring the voltage value at both ends of the detection resistor 220, reducing the hardware cost. Since the detection method of the detection circuit in this application is simple, the detection efficiency of the relay can also be improved.

[0038] In an exemplary embodiment, the detection power supply 210 is a low-voltage power supply.

[0039] The low-voltage power supply in this embodiment is obtained based on the safety of the power supply to the human body. Specifically, a power supply of 36V or less is defined as a low-voltage power supply, and a power supply of more than 36V is defined as a high-voltage power supply. In this embodiment, a low-voltage power supply is used as the detection power supply 210, which improves the safety of the detection personnel during the relay adhesion detection and avoids potential safety hazards during high-voltage detection, with good reliability. Further, when the detection power supply 210 is a low-voltage power supply, the voltage acquired by the voltage acquisition circuit 230 is also a low-voltage, so the device requirements for the voltage acquisition circuit 230 are not high, and the hardware cost of the voltage acquisition circuit 230 is also saved.

[0040] It can be understood that the above detection power supply 210 can also adopt other forms, not limited to the forms already mentioned in the above embodiments, as long as it can form a current passing through the detection resistor 220, generate a voltage difference across the detection resistor 220, and enable the voltage acquisition circuit 230 to acquire the voltage across the detection resistor 220.

[0041] In a specific embodiment, the detection power supply 210 includes a 12V power supply or a 24V power supply.

[0042] Among them, the 12V power supply is a relatively common low-voltage power supply, which can meet the detection requirements under low-power conditions. For high-power detection requirements, a 24V power supply can be set as the low-voltage power supply. In practical applications, a specific low-voltage power supply can be selected according to different circuit components and application scenarios.

[0043] In another exemplary embodiment, the first relay 100 includes one or more of a main negative relay, a main positive relay, a pre-charge relay, a fast charge relay, and a heating relay.

[0044] Among them, the relay is a device used to connect the battery module to the high-voltage power supply. By controlling the closing or opening of the relay, the connection or disconnection between the battery module and the high-voltage power supply is achieved. That is, if the relay is closed, the battery module is connected to the high-voltage power supply, and the high-voltage power supply starts to charge the battery module, and the charging starts. If the relay is opened, the battery module is disconnected from the high-voltage power supply, and the high-voltage power supply stops charging the battery module, and the charging ends.

[0045] Specifically, the positive electrode of the battery module and the negative electrode of the battery module are respectively connected to different relays. In addition, according to different application requirements, the relay connected to the positive electrode of the battery module may also include a main positive relay, a pre-charge relay, a fast charge relay, a heating relay, and so on.

[0046] Exemplarily, the main negative relay is a relay connected to the negative electrode of the battery module, which is used to conduct or disconnect the connection with the negative electrode of the battery module. The main positive relay is a relay connected to the positive electrode of the battery module, which is used to conduct or disconnect the connection with the positive electrode of the battery module. The pre-charge relay is a relay used to pre-charge the battery module, which is used to conduct or disconnect the connection with the pre-charge terminal of the battery module. The fast charge relay is used to conduct or disconnect the connection with the fast charge terminal of the battery module. The heating relay is used to control the heating of the battery module, and is applicable to lithium iron phosphate batteries with certain requirements for the battery operating temperature.

[0047] This embodiment can be used for detecting the adhesion of various types of relays. Therefore, there is no limitation on the type of the first relay 100 in this embodiment, and it can be any relay in the battery pack PACK, or any number of different types of relays.

[0048] In another specific embodiment, the detection resistor 220 includes a resistor with a resistance value range of 1kΩ - 100kΩ.

[0049] Among them, when the detection power supply 210 is a low-voltage power supply, the resistance value of the detection resistor 220 is related to the voltage magnitude that can be collected by the voltage acquisition circuit 230. Limiting the resistance value range of the detection resistor 220 to 1 kΩ - 100 kΩ can avoid excessive current in the detection circuit and prevent the excessive current in the detection circuit from affecting other circuits. Preferably, to better balance the current in the relay detection circuit, the detection resistor 220 is a resistor with a resistance value of 10 kΩ.

[0050] As Figure 2 shown, in one embodiment, a battery management system is provided. The battery management system includes the relay adhesion detection circuit proposed in the foregoing embodiments, and further includes an MCU module 310; wherein, the MCU module 310 is connected to the first relay 100 and is used to control the opening or closing of the first relay 100.

[0051] A battery management system (abbreviated as BMS, Battery Management System) is a device used to monitor the battery state. Through the monitoring of the battery state, the battery management system realizes the intelligentization of battery management, prevents the battery from overcharging and over-discharging, and prolongs the service life of the battery.

[0052] The MCU module 310 is a control unit set in the battery management system. The battery management system controls the first relay 100 through the MCU module 310 and controls the opening or closing of the first relay 100 according to different charging states. When the first relay 100 is multiple relays, the MCU module 310 correspondingly controls multiple relays.

[0053] In another embodiment, as Figure 3 shown, in the battery management system of an embodiment, the MCU module 310 is further connected to the above relay adhesion detection circuit and is used to receive the target voltage value collected by the relay adhesion detection circuit, so as to judge whether the first relay 100 is adhered according to the target voltage value and the state of the first relay 100.

[0054] When the MCU module 310 is connected to the relay adhesion detection circuit, it can be connected to the voltage acquisition circuit 230 in the relay adhesion detection circuit to obtain the target voltage value collected by the voltage acquisition circuit 230. And judge whether the first relay 100 is adhered according to the obtained target voltage value and the obtained working state of the first relay 100.

[0055] Exemplarily, taking the disconnection control of the first relay 100 as an example. The initial voltage value across the detection resistor 220 collected by the voltage acquisition circuit 230 and obtained by the MCU module 310 is denoted as V1. The MCU module 310 sends a power-off instruction to the first relay 100, and the first relay 100 disconnects according to the received power-off instruction. After a preset time period (e.g., after 300 ms), the voltage value across the detection resistor 220 collected by the voltage acquisition circuit 230 is obtained again through the MCU module 310, and this voltage value is denoted as V2. The voltage value V1 and the voltage value V2 are compared. V1 should be close to the voltage value provided by the detection power supply 210, and V2 should be zero. If the obtained V1 and V2 are equal or close, it indicates that the first relay 100 is stuck.

[0056] Similarly, the detection method for whether the first relay 100 is stuck when it is closed is similar and will not be elaborated here.

[0057] In this embodiment, the voltage value collected by the voltage acquisition circuit 230 and obtained by the MCU module 310 in the battery management system is associated with the working state of the first relay 100 obtained by the MCU module 310. Combining the voltage value across the detection resistor 220 with the working state of the first relay 100, the stuck detection of the first relay 100 is realized, and the operation is simple and easy to implement.

[0058] In an exemplary embodiment, as Figure 4 shown, the detection power supply 210 is connected to the battery management system and is used to supply power to the battery management system.

[0059] The working power supply of the battery management system can be an external power supply. In some cases, the battery management system can also be powered by a battery module or a backup battery. As in this embodiment Figure 4 shown, the detection power supply 210 in the relay stuck detection circuit is used as the power module of the battery association system to supply power to the battery management system. In this embodiment, the power supply of the battery management system is used as the detection power supply 210 for relay stuck detection, which reduces the complexity of circuit connection and also reduces the hardware cost of the relay stuck detection circuit.

[0060] In a specific embodiment, as Figure 5 shown, the first relay 100 in the battery management system is the main negative relay.

[0061] As Figure 5 shown, since there is only a main negative relay between the negative electrode of the battery module and the negative electrode of the high-voltage power supply. Therefore, the main negative relay is a relatively important relay in the battery pack PACK, and the effectiveness detection of the main negative relay is particularly important.

[0062] In this embodiment, the main negative relay in the battery PACK is used as the first relay 100, and the above-mentioned relay adhesion detection circuit is arranged in the battery management system and connected to the main negative relay for detecting the adhesion of the main negative relay.

[0063] In another embodiment, the battery management system is also connected to a second relay 400 for controlling the opening or closing of the second relay 400; where: the second relay 400 is one or more of a main positive relay, a pre-charge relay, a fast charge relay, and a heating relay.

[0064] As Figure 5 shown, the battery module includes two connection terminals, namely the battery total positive and the battery total negative. The battery total positive connection terminal leads out the positive connection terminal of the battery module for connecting to the positive extreme of the high-voltage power supply main circuit; the battery total negative connection terminal leads out the negative connection terminal of the battery module for connecting to the negative extreme of the high-voltage power supply main circuit. As Figure 5 shown, between the positive connection terminal of the battery module and the positive extreme of the high-voltage power supply main circuit, there are a main positive relay and a pre-charge relay 510 connected in parallel, and the pre-charge relay 510 is also connected in series with a pre-charge resistor 520. Between the negative connection terminal of the battery module and the negative extreme of the high-voltage power supply main circuit, there is a main negative relay.

[0065] Taking the charging of the Figure 5 shown battery module as an example, the closing sequence of each relay is to first close the pre-charge relay 510, then close the main negative relay, and finally close the main positive relay. By closing the pre-charge relay, a small current is allowed to pass through the pre-charge resistor 520 to balance the voltage between the high-voltage power supply and the battery module, which helps to reduce the current impact caused by the voltage difference across the relay at the beginning of charging and avoid the adhesion and damage of the main positive and main negative relays due to overcurrent or overheating. The pre-charge resistor 520 is used to limit the current passing through the pre-charge relay 510, while balancing the voltage and preventing overcurrent from damaging the battery and the circuit.

[0066] After the pre-charge relay 510 is closed for a period of time, the main negative relay is closed to connect the negative connection terminal of the battery module to the negative pole of the high-voltage power supply charging circuit. Finally, the main positive relay is closed to connect the positive connection terminal of the battery module to the positive pole of the high-voltage power supply charging circuit, realizing the connection between the battery module and the high-voltage power supply for normal charging operation.

[0067] When it is necessary to stop charging the charging module, the disconnection sequence of each relay is opposite to the closing sequence, that is, first disconnect the main positive relay, then disconnect the main negative relay, and finally disconnect the pre-charge relay to ensure the safety of the battery system and protect the circuit.

[0068] As Figure 5As shown, the battery management system is respectively connected to the main positive relay, the main negative relay, and the pre-charge relay, and is used to control the closing and opening of the main positive relay, the main negative relay, and the pre-charge relay. In the battery management system, there is an MCU module 310, a power supply module for powering the battery management system, and a relay adhesion detection circuit for detecting the adhesion of the main negative relay.

[0069] As described above, the relay adhesion detection circuit includes a detection power supply 210 and a detection resistor 220 connected in series with the main negative relay, and a voltage acquisition circuit 230 connected in parallel with the detection resistor 220. Specifically, the relay adhesion detection circuit reuses the power supply module of the battery management system as the detection power supply 210. The relay adhesion detection circuit realizes the adhesion detection of the main negative relay through the target voltage value collected by the voltage acquisition circuit 230 and the judgment of the working state of the main negative relay. The reuse of the detection power supply 210 reduces the hardware cost of the relay adhesion detection circuit and improves the detection efficiency of the main negative relay.

[0070] The above relay adhesion detection circuit can be applied to electronic devices or similar devices such as new energy vehicle charging devices.

[0071] In the description of this specification, the descriptions referring to terms such as "some embodiments", "other embodiments", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0072] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0073] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A relay adhesion detection circuit, characterized in that: include: A detection power supply is connected in series with the first relay to be detected; a detection resistor, connected in series with the detection power supply and the first relay respectively; A voltage acquisition circuit is connected in parallel with the detection resistor and is used to acquire a target voltage value of the detection resistor, so as to determine whether the first relay is stuck according to the target voltage value; wherein: One end of the first relay is used to connect to the battery module, and the other end is used to connect to the high-voltage power supply; the detection power supply, the detection resistor and the first relay form a detection loop.

2. The relay adhesion detection circuit according to claim 1, characterized in that: The detection power supply is a low voltage power supply.

3. The relay adhesion detection circuit according to claim 2, characterized in that: The detection power supply includes a 12V power supply or a 24V power supply.

4. The relay adhesion detection circuit according to claim 1, characterized in that: The first relay includes one or more of a main negative relay, a main positive relay, a pre-charge relay, a fast charge relay and a heating relay.

5. The relay adhesion detection circuit according to claim 1, characterized in that: The detection resistor includes a resistor with a resistance range of 1 kΩ-100 kΩ.

6. A battery management system, characterized in that: Including the relay adhesion detection circuit as described in any one of claims 1-5, the battery management system also includes an MCU module, the MCU module is connected to the first relay, and is used to control the opening or closing of the first relay.

7. The battery management system according to claim 6, characterized in that: The MCU module is also connected to the detection circuit, and is used to receive the target voltage value collected by the detection circuit, so as to determine whether the first relay is stuck according to the target voltage value and the state of the first relay.

8. The battery management system according to claim 6, characterized in that: The detection power supply is connected to the battery management system and is used to supply power to the battery management system.

9. The battery management system according to any one of claims 6 to 8, characterized in that: The first relay is a main negative relay.

10. The battery management system according to claim 9, characterized in that: The battery management system is also connected to a second relay for controlling the opening or closing of the second relay; wherein: the second relay is one or more of a main positive relay, a pre-charge relay, a fast charge relay and a heating relay.

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