Switch testing circuit and testing method for high-voltage battery packs, and electric vehicle

Abstract

The present application relates to a switch testing circuit and testing method for high-voltage battery packs, and an electric vehicle. The switch testing circuit comprises at least two measurement circuits, and each measurement circuit is arranged between a negative electrode of a high-voltage battery pack and a load or a power supply, a negative electrode switch of the high-voltage battery pack being connected in parallel with the measurement circuit, and a positive electrode switch of the high-voltage battery pack being connected in series between a positive electrode of the high-voltage battery pack and the load or the power supply. Each measurement circuit is provided with a negative electrode switch testing point and is used for measuring the test voltage of the negative electrode switch when the high-voltage battery pack is in a power-on or power-off state and, on the basis of the test voltage, determining the state of the negative electrode switch. A positive electrode switch testing point is provided between the positive electrode of each high-voltage battery pack and the load or the power supply, and is used for measuring the test voltage of the positive electrode switch when the high-voltage battery pack is in the power-on or power-off state and, on the basis of the test voltage, determining the state of the positive electrode switch. The technical solution of the present application solves the problem in the prior art of being unable to diagnose the states of high-voltage switches of multiple battery packs.

Description

High-voltage battery pack switch detection circuit, detection method, and electric vehicle

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on June 28, 2023, with application number 2023107779896 and application name “Switch detection circuit, detection method and electric vehicle for high-voltage battery pack”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of circuit detection technology, and in particular to a switch detection circuit, a detection method, and an electric vehicle for a high-voltage battery pack. Background Art

[0003] The high voltage control of the power battery is achieved by connecting the high voltage load through the closing and opening of the high voltage switch, thereby realizing charging and discharging. Therefore, it is necessary to diagnose the status of the high voltage switch.

[0004] In the related art, most of the solutions are for diagnosing the high-voltage switch status of a single battery pack, and there is a lack of solutions for diagnosing the high-voltage switch status of multiple battery packs (such as a dual battery pack) connected in parallel.

[0005] Summary of the Invention

[0006] In order to solve or partially solve the problems existing in the related art, the present application provides a switch detection circuit, a detection method and an electric vehicle for a high-voltage battery pack, so as to realize the high-voltage switch status diagnosis of multiple battery packs.

[0007] In a first aspect, the present application provides a switch detection circuit for a high-voltage battery pack, comprising at least two detection circuits, each of which is disposed between a negative electrode of a high-voltage battery pack and a load or a power source;

[0008] The negative electrode switch of the high-voltage battery pack is connected in parallel with the detection circuit, and the positive electrode switch of the high-voltage battery pack is connected in series between the positive electrode of the high-voltage battery pack and the load or power supply;

[0009] The detection circuit is provided with a negative switch detection point for detecting a detection voltage of the negative switch when the high-voltage battery pack is in a powered-on or powered-off state, and determining a state of the negative switch based on the detection voltage;

[0010] A positive switch detection point is provided between the positive electrode of the high-voltage battery pack and the load or power supply, which is used to detect the detection voltage of the positive switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the positive switch based on the detection voltage.

[0011] A second aspect of the present application provides a switch detection method for a high-voltage battery pack, comprising:

[0012] Obtaining voltage information of at least two high-voltage battery packs, the at least two high-voltage battery packs comprising a first high-voltage battery pack and a second high-voltage battery pack; wherein a detection circuit is provided between a negative electrode of each high-voltage battery pack and a load or power source, the detection circuit being provided with a negative electrode switch detection point, and a positive electrode switch detection point is provided between a positive electrode of each high-voltage battery pack and the load or power source;

[0013] determining a power-on or power-off sequence of the first high-voltage battery pack and the second high-voltage battery pack according to voltage information of the at least two high-voltage battery packs;

[0014] When the first high-voltage battery pack is powered on or off, the positive switch and the negative switch of the first high-voltage battery pack are controlled to be closed or opened according to a preset first execution sequence, the detection voltage of the negative switch is detected through the negative switch detection point, and the state of the negative switch is determined based on the detection voltage; the detection voltage of the positive switch is detected through the positive switch detection point, and the state of the positive switch is determined based on the detection voltage;

[0015] When the second high-voltage battery pack is powered on or off, the positive and negative switches of the second high-voltage battery pack are controlled to close or open according to a preset second execution sequence, the detection voltage of the negative switch is detected through the negative switch detection point, and the state of the negative switch is determined based on the detection voltage; the detection voltage of the positive switch is detected through the positive switch detection point, and the state of the positive switch is determined based on the detection voltage. A third aspect of the present application provides an electric vehicle, comprising: a processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein the computer program, when executed by the processor, implements the method described above.

[0016] A fourth aspect of the present application provides an electric vehicle comprising the switch detection circuit of the high-voltage battery pack as described above.

[0017] The technical solution provided by this application may have the following beneficial effects:

[0018] The technical solution of the present application provides a switch detection circuit for a high-voltage battery pack, comprising at least two detection circuits, each of which is arranged between the negative pole of a high-voltage battery pack and a load or power supply; wherein the negative pole switch of the high-voltage battery pack is connected in parallel with the detection circuit, and the positive pole switch of the high-voltage battery pack is connected in series between the positive pole of the high-voltage battery pack and the load or power supply; the detection circuit is provided with a negative pole switch detection point for detecting the detection voltage of the negative pole switch when the high-voltage battery pack is in a powered-on or powered-off state, and determining the state of the negative pole switch based on the detection voltage; a positive pole switch detection point is provided between the positive pole of the high-voltage battery pack and the load or power supply, for detecting the detection voltage of the positive pole switch when the high-voltage battery pack is in a powered-on or powered-off state, and determining the state of the positive pole switch based on the detection voltage. The technical solution of the present application is to set a detection circuit in parallel on each negative switch, and diagnose the status of each negative switch by detecting the detection voltage at the negative switch detection point set in the detection circuit, and diagnose the status of each positive switch by detecting the detection voltage at the positive switch detection point set on the positive switch, thereby solving the problem in related technologies that it is impossible to diagnose the status of high-voltage switches of multiple battery packs.

[0019] The present application also discloses a switch detection method for a high-voltage battery pack and an electric vehicle, which can achieve the same technical effect as the switch detection circuit for the high-voltage battery pack.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0022] FIG1 is a schematic diagram of a switch detection circuit structure of a high-voltage battery pack in the related art;

[0023] FIG2 is a schematic diagram of a switch detection circuit structure of a high-voltage battery pack according to an embodiment of the present application;

[0024] FIG3 is a schematic diagram of the specific structure of a switch detection circuit of a high-voltage battery pack shown in an embodiment of the present application;

[0025] FIG4 is a schematic diagram of another specific structure of a switch detection circuit of a high-voltage battery pack shown in an embodiment of the present application;

[0026] FIG5 is a schematic diagram of another specific structure of a switch detection circuit of a high-voltage battery pack shown in an embodiment of the present application;

[0027] FIG6 is a schematic flow chart of a switch detection method for a high-voltage battery pack according to an embodiment of the present application;

[0028] FIG7 is a schematic structural diagram of a specific embodiment of a switch detection circuit for a high-voltage battery pack shown in an embodiment of the present application. DETAILED DESCRIPTION

[0029] The following describes embodiments of the present application in more detail with reference to the accompanying drawings. Although the accompanying drawings illustrate embodiments of the present application, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0030] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0031] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] The state detection method of the high-voltage relay of a single battery pack mentioned in the related art is shown in Figure 1. The power-on sequence of a single battery pack is to close the main negative relay, then close the pre-charge relay, then close the main positive relay, and finally close the main positive relay before disconnecting the pre-charge relay; the power-off sequence of a single battery pack is to disconnect the main positive relay first and then disconnect the main negative relay. In the related art, whether the high-voltage relay is disconnected or closed, the diagnosis method is the same, that is, by closing and disconnecting the V AB and V BC The difference between the two determines the state of the main positive relay, and the V BD The voltage of the main negative relay is used to determine the status of the main negative relay.

[0033] During the research, the applicant found that in order to provide the vehicle with greater power and more energy, a multi-battery pack parallel system was proposed. However, the current high-voltage relay status diagnosis method is usually for a single battery pack. If the status diagnosis method of a single battery pack high-voltage relay is continued to be used to diagnose the status of the high-voltage relays in the multi-battery pack parallel system, when the high voltage of one battery pack circuit is powered on, the load end is in a high-voltage state. At this time, the high-voltage sampling of the other battery pack circuit will cause interference, making it impossible to diagnose the status of each high-voltage relay in the other battery pack circuit. Therefore, although this diagnostic method for a single battery pack is simple, it cannot be borrowed by a multi-battery pack parallel system. For this reason, it is necessary to find a new diagnostic method to complete the status diagnosis of each high-voltage relay in the multi-battery pack parallel system.

[0034] In response to the above problems, the present application provides a switch detection circuit, a switch detection method and an electric vehicle for a high-voltage battery pack, so as to realize the status diagnosis of high-voltage relays of multiple battery packs.

[0035] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] As shown in Figure 2, an embodiment of the present application provides a switch detection circuit for a high-voltage battery pack, including at least two detection circuits, each of which is arranged between the negative pole of a high-voltage battery pack and a load or power supply; wherein, the negative pole switch of the high-voltage battery pack is connected in parallel with the detection circuit, and the positive pole switch of the high-voltage battery pack is connected in series between the positive pole of the high-voltage battery pack and the load or power supply; the detection circuit is provided with a negative pole switch detection point, which is used to detect the detection voltage of the negative pole switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the negative pole switch based on the detection voltage; a positive pole switch detection point is provided between the positive pole of the high-voltage battery pack and the load or power supply, which is used to detect the detection voltage of the positive pole switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the positive pole switch based on the detection voltage.

[0037] The core concept of the present application includes setting a detection circuit in parallel with the negative switch of each battery pack circuit, and providing a negative switch detection point on each detection circuit. The state of the negative switch can be determined by detecting the detection voltage of the negative switch detection point; and the state of the positive switch can be determined by detecting the detection voltage of the positive switch detection point.

[0038] Referring to FIG3 , FIG3 is a schematic diagram of a switch detection circuit structure of a high-voltage battery pack according to an embodiment of the present application. As shown in FIG3 , the switch detection circuit of the high-voltage battery pack provided by the embodiment of the present application includes: two detection circuits, each of which is arranged between the negative electrode of a high-voltage battery pack and a load or power supply; wherein the negative electrode switch of the high-voltage battery pack is connected in parallel with the detection circuit, and the positive electrode switch of the high-voltage battery pack is connected in series between the positive electrode of the high-voltage battery pack and the load or power supply; the detection circuit is provided with negative electrode switch detection points (P1 and P2) for detecting the detection voltage of the negative electrode switch when the high-voltage battery pack is in a powered-on or powered-off state, and determining the state of the negative electrode switch based on the detection voltage; positive electrode switch detection points (1, 3, 4, 6) are provided between the positive electrode of the high-voltage battery pack and the load or power supply, and positive electrode switch detection points (2 and 5) are provided between the negative electrode of the high-voltage battery pack and the negative electrode switch, for detecting the detection voltage of the positive electrode switch when the high-voltage battery pack is in a powered-on or powered-off state, and determining the state of the positive electrode switch based on the detection voltage.

[0039] As shown in Figure 3, a negative pole detection point P1 is provided on the first detection circuit, a positive pole switch detection point 1 is provided between the positive output terminal (+) of the first battery pack and the first positive switch, a positive pole switch detection point 2 is provided between the negative output terminal (-) of the first battery pack and the first negative switch, and a positive pole switch detection point 3 is provided between the positive switch and the high-voltage positive terminal (P+). A negative pole detection point P2 is provided on the second detection circuit, a positive pole switch detection point 4 is provided between the positive output terminal (+) of the second battery pack and the second positive switch, a positive pole switch detection point 5 is provided between the negative output terminal (-) of the second battery pack and the second negative switch, and a positive pole switch detection point 6 is provided between the second positive switch and the high-voltage positive terminal (P+).

[0040] As shown in Figure 4, in a specific embodiment, the detection circuit includes a low-voltage power supply, a voltage divider circuit and a shunt circuit, wherein: the voltage divider circuit is connected between the low-voltage power supply and the load or power supply, and the negative pole switch detection point is set at the voltage divider point of the voltage divider circuit; the shunt circuit is connected between the negative pole switch detection point and the negative pole of the high-voltage battery pack, and the shunt circuit is a passage when the negative pole switch is closed, and the shunt circuit is an open circuit when the negative pole switch is disconnected.

[0041] In a specific embodiment, as shown in Figure 5, the voltage divider circuit includes a first resistor R1 and a second resistor R2, and the shunt circuit includes a third resistor R3 and a first switching tube MOS1; the first resistor R1 and the second resistor R2 are connected in series between the low-voltage power supply (5V) and the load or power supply, the negative pole switch detection point (P1 and P2) is set between the first resistor R1 and the second resistor R2, and the third resistor R3 and the first switching tube MOS1 are connected in series between the negative pole switch detection point (P1 and P2) and the negative pole of the high-voltage battery pack.

[0042] In a specific embodiment, as shown in Figure 5, the first end of the third resistor R3 is connected to the negative electrode of the high-voltage battery pack, and the second end of the third resistor R3 is connected in parallel to the first end of the first resistor R1 and the first end of the second resistor R2 through the first switch tube MOS1. The first end of the first resistor R1 is connected in series with the first end of the second resistor R2. The second end of the first resistor R1 is connected to the low-voltage power supply (5V), and the second end of the second resistor R2 is connected to the load or power supply. In a specific embodiment, the first resistor R1, the second resistor R2, and the third resistor R3 can be set to different values ​​as needed. In the embodiment of the present application, it is assumed that R1=R2=R3. It should be noted that the negative electrode switch and the first switch tube MOS1 are opened and closed at the same time.

[0043] In a specific embodiment, as shown in Figures 2-5, the positive switch detection points provided between the positive electrode of the high-voltage battery pack and the load or power supply include: a first positive switch detection point provided between the positive electrode of the high-voltage battery pack and the positive switch, a second positive switch detection point provided between the positive switch and the load or power supply; and a third positive switch detection point provided between the negative electrode of the high-voltage battery pack and the negative switch. The first, second, and third positive switch detection points are used to detect a detection voltage of the positive switch when the high-voltage battery pack is in a powered-on or powered-off state, and determine the state of the positive switch based on the detection voltage. A negative switch detection point is provided between the negative switch and the load or power supply, and the negative switch detection point is used to detect a detection voltage of the negative switch when the high-voltage battery pack is in a powered-on or powered-off state, and determine the state of the negative switch based on the detection voltage.

[0044] An embodiment of the present application provides a switch detection circuit for a high-voltage battery pack, comprising at least two detection circuits, each of which is arranged between the negative pole of a high-voltage battery pack and a load or power supply; wherein the negative pole switch of the high-voltage battery pack is connected in parallel with the detection circuit, and the positive pole switch of the high-voltage battery pack is connected in series between the positive pole of the high-voltage battery pack and the load or power supply; the detection circuit is provided with a negative pole switch detection point, which is used to detect the detection voltage of the negative pole switch when the high-voltage battery pack is in a powered-on or powered-off state, and determine the state of the negative pole switch based on the detection voltage; a positive pole switch detection point is provided between the positive pole of the high-voltage battery pack and the load or power supply, which is used to detect the detection voltage of the positive pole switch when the high-voltage battery pack is in a powered-on or powered-off state, and determine the state of the positive pole switch based on the detection voltage. The technical solution of the present application is to set a detection circuit in parallel on each negative switch, and diagnose the status of each negative switch by detecting the detection voltage at the negative switch detection point set in the detection circuit, and diagnose the status of each positive switch by detecting the detection voltage at the positive switch detection point set on the positive switch, thereby solving the problem in related technologies that it is impossible to diagnose the status of high-voltage switches of multiple battery packs.

[0045] 6 , an embodiment of the present application provides a switch detection method for a high-voltage battery pack, the method comprising:

[0046] S601: Obtaining voltage information of at least two high-voltage battery packs, the at least two high-voltage battery packs including a first high-voltage battery pack and a second high-voltage battery pack; wherein a detection circuit is provided between a negative electrode of each high-voltage battery pack and a load or power source, the detection circuit being provided with a negative electrode switch detection point, and a positive electrode switch detection point being provided between a positive electrode of each high-voltage battery pack and the load or power source;

[0047] S602: Determine a power-on or power-off sequence of the first high-voltage battery pack and the second high-voltage battery pack according to voltage information of the at least two high-voltage battery packs;

[0048] S603: When the first high-voltage battery pack is powered on or off, controlling the positive switch and the negative switch of the first high-voltage battery pack to be closed or opened according to a preset first execution order, detecting a detection voltage of the negative switch via the negative switch detection point, and determining a state of the negative switch based on the detection voltage; detecting a detection voltage of the positive switch via the positive switch detection point, and determining a state of the positive switch based on the detection voltage;

[0049] S604: When the second high-voltage battery pack is powered on or off, the positive switch and the negative switch of the second high-voltage battery pack are controlled to be closed or opened according to a preset second execution order, the detection voltage of the negative switch is detected through the negative switch detection point, and the state of the negative switch is determined based on the detection voltage; the detection voltage of the positive switch is detected through the positive switch detection point, and the state of the positive switch is determined based on the detection voltage.

[0050] In a specific embodiment, the first battery pack circuit and the second battery pack circuit may each include multiple high-voltage relays. For a high-voltage circuit with two battery packs connected in parallel, the high voltage generated after the first battery pack circuit is closed and powered on will cause the second battery pack circuit, which is not closed and powered on, to generate high voltage, thereby affecting the high-voltage sampling of the second battery pack circuit. When performing diagnosis based on the high-voltage sampling of the second battery pack circuit, the diagnosis of the high-voltage relay fault status will be inaccurate, making it impossible to accurately determine whether the high-voltage relays in the second battery pack circuit are effectively controlled.

[0051] In an embodiment of the present application, a detection circuit is provided in parallel with the negative electrode switches of the first battery pack circuit and the second battery pack circuit, and the state of the negative electrode switches in the first battery pack circuit and the second battery pack circuit is determined by detecting the voltage at the negative electrode switch detection point on each of the detection circuits.

[0052] The positive switch detection point provided between the positive electrode of each high-voltage battery pack and the load or power supply includes: a first positive switch detection point provided between the positive electrode of each high-voltage battery pack and the positive switch, and a second positive switch detection point provided between the positive switch and the load or power supply;

[0053] A third positive switch detection point is provided between the negative electrode of each high-voltage battery pack and the negative electrode switch;

[0054] The first positive switch detection point, the second positive switch detection point and the third positive switch detection point are used to detect the detection voltage of the positive switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the positive switch based on the detection voltage.

[0055] Those skilled in the art should understand that the above-mentioned high-voltage battery pack switch detection method applied to the switch detection circuit of the high-voltage battery pack is merely an example of the present application, and those skilled in the art can apply this method to the switch detection circuit of the high-voltage battery pack in actual applications.

[0056] The embodiment of the present application effectively, accurately and reliably determines the status of the positive switch and the negative switch in each battery pack circuit by collecting the voltage value of the negative switch detection point and the voltage value of the positive switch detection point.

[0057] Those skilled in the art should understand that the above-mentioned first battery pack circuit structure and second battery pack circuit structure are merely examples of the present application. Those skilled in the art may adopt other battery pack circuit structures, and the present application does not limit them here.

[0058] Those skilled in the art should understand that the above-mentioned detection circuit structure is only an example of the present application, and those skilled in the art may use other detection circuit structures to diagnose the status of the main negative relay, which is not limited in this field.

[0059] In a specific embodiment, when the first high-voltage battery pack and the second high-voltage battery pack are powered on, the negative switch is closed before the positive switch in the first execution sequence; and the positive switch is closed before the negative switch in the second execution sequence.

[0060] In a specific embodiment, when the first high-voltage battery pack and the second high-voltage battery pack are powered off, the negative switch is disconnected before the positive switch in the first execution sequence; and the negative switch is disconnected before the positive switch in the second execution sequence.

[0061] In a specific embodiment, determining the power-on sequence of the first high-voltage battery pack and the second high-voltage battery pack according to the voltage information of the at least two high-voltage battery packs includes:

[0062] According to the voltage information of the first high-voltage battery pack being greater than the voltage information of the second high-voltage battery pack, it is determined that the first high-voltage battery pack is powered on with priority over the second high-voltage battery pack.

[0063] In a specific embodiment, the negative switch includes a main negative relay, the detection circuit includes a first switch tube, and the positive switch includes a main positive relay and a pre-charge relay;

[0064] When the first high-voltage battery pack and the second high-voltage battery pack are powered on, controlling the positive switch and the negative switch of the first high-voltage battery pack to be closed according to a preset first execution order includes:

[0065] For the first high-voltage battery pack, first close the main negative relay and the first switch tube, then close the pre-charge relay, and finally close the main positive relay;

[0066] The controlling the positive switch and the negative switch of the second high-voltage battery pack to be closed according to a preset second execution order includes:

[0067] For the second high-voltage battery pack, the main positive relay is closed first, and then the main negative relay and the first switch tube are closed, and the pre-charge relay is not closed.

[0068] In a specific embodiment, the negative switch includes a main negative relay, the detection circuit includes a first switch tube, and the positive switch includes a main positive relay and a pre-charge relay;

[0069] When the first high-voltage battery pack and the second high-voltage battery pack are powered off, controlling the positive switch and the negative switch of the first high-voltage battery pack to be disconnected according to a preset first execution order includes:

[0070] For the first high-voltage battery pack, first disconnect the main negative relay, and then disconnect the main positive relay;

[0071] The controlling the positive switch and the negative switch of the second high-voltage battery pack to be disconnected according to a preset second execution order includes:

[0072] For the second high-voltage battery pack, the main negative relay is disconnected first, and then the main positive relay is disconnected.

[0073] It should be noted that, in a specific embodiment, as shown in FIG7 , for the first battery pack circuit, before the main negative relay K3 is closed, the voltage at the detection point 6 is 5V. After the main negative relay K3 is closed, the voltage at the first detection point P1, i.e., the detection point 6, is 1.67V. In other words, if the voltage at the detection point 6 is detected to be 5V, it can be determined that the main negative relay K3 is in the open state; if the voltage at the detection point 6 is detected to be 1.67V, it is determined that the main negative relay K3 is in the closed state. In the embodiment of the present application, the resistance values ​​of the first resistor R1, the second resistor R2, and the third resistor R3 are the same. When the main negative relay K3 is closed, the voltage at the first detection point P1 is the voltage of the second resistor R2 and the third resistor R3 in parallel to the ground, i.e., the first voltage value V1 = 5 / 3 = 1.67V, and the front end of the main negative relay K3 is equivalent to GND. It should be noted that the voltage value to be judged can be set according to the resistance in the system and is not specifically limited here.

[0074] It should be noted that in a specific embodiment, as shown in FIG7 , for the second battery pack circuit, before the main negative relay K3 is closed, the voltage at detection point 6 is 2.5V. After the main negative relay K3 is closed, the voltage at detection point 6 is 1.67V. In other words, if the voltage at detection point 6 is 2.5V, it can be determined that the main negative relay K3 is in the open state; if the voltage at detection point 6 is 1.67V, it can be determined that the main negative relay K3 is in the closed state. In this embodiment of the present application, the front end of the main negative relay K3 is equivalent to the ground. Therefore, when the main negative relay K3 of the first battery pack circuit is closed, the two packs are connected in parallel. Therefore, the second resistor R2 of the second battery pack circuit is now connected to the ground. The two identical resistors divide the 5V voltage, that is, the second voltage value V2 = 5 / 2 = 2.5V. When the main negative relay K3 is closed, the third resistor R3 is also connected to the system in parallel with the second resistor R2. The voltage across the second resistor R2 and the third resistor R3 connected in parallel and in series with the second resistor R1 is measured. The second voltage value V2 = 1.67 V. It should be noted that the voltage value to be determined can be set based on the resistors in the system and is not specifically limited here.

[0075] It should be noted that in a specific embodiment, as shown in Figure 7, for the first battery pack circuit, before the main negative relay K3 is disconnected, the voltage at detection point 6 is 1.67V. After the main negative relay K3 is disconnected, the voltage at detection point 6 is 2.5V. In other words, if the voltage at detection point 6 is 1.67V, it can be determined that the main negative relay K3 is in the closed state; if the voltage at detection point 6 is 2.5V, it can be determined that the main negative relay K3 is in the open state. It should be noted that the voltage value used for determination can be set based on the resistance in the system and is not specifically limited here.

[0076] It should be noted that in a specific embodiment, as shown in Figure 7, for the second battery pack circuit, before the main negative relay K3 is disconnected, the voltage at detection point 6 is 2.5V, and after the main negative relay K3 is disconnected, the voltage at detection point 6 is 5V. In other words, if the voltage at detection point 6 is 2.5V, it can be determined that the main negative relay K3 is in the closed state; if the voltage at detection point 6 is 5V, it can be determined that the main negative relay K3 is in the open state. It should be noted that the voltage value used for determination can be set based on the resistance in the system and is not specifically limited here.

[0077] It should be noted that in the specific embodiment, as shown in Figure 7, for the first battery pack circuit, |V25-V45| > 100V before the main positive relay K1 is closed, and |V25-V45| < 10V after the main positive relay K1 is closed. In other words, when |V25-V45| > 100V is detected, the main positive relay K1 is in the open state; when |V25-V45| < 10V is detected, the main positive relay K1 is in the closed state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

[0078] It should be noted that in the specific embodiment, as shown in Figure 7, for the second battery pack circuit, |V25-V45| > 30V before the main positive relay K1 is closed, and |V25-V45| < 10V after the main positive relay K1 is closed. In other words, when |V25-V45| > 30V is detected, the main positive relay K1 is in the open state; when |V25-V45| < 10V is detected, the main positive relay K1 is in the closed state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

[0079] It should be noted that in the specific embodiment, as shown in Figure 7, for the first battery pack circuit, |V25-V45| < 10V before the main positive relay K1 is disconnected, and |V25-V45| > 30V after the main positive relay K1 is disconnected. In other words, when |V25-V45| < 10V is detected, the main positive relay K1 is in the closed state; when |V25-V45| > 30V is detected, the main positive relay K1 is in the open state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

[0080] It should be noted that in the specific embodiment, as shown in Figure 7, for the second battery pack circuit, |V25-V45| < 10V before the main positive relay K1 is disconnected, and |V25-V45| > 100V after the K1 main positive relay is disconnected. In other words, when |V25-V45| < 10V is detected, the main positive relay K1 is in the closed state; when |V25-V45| > 100V is detected, the main positive relay K1 is in the open state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

[0081] BMS (Battery Management System) is an important link between the on-board power battery and the electric vehicle, and can collect, process and store important information during the operation of the battery pack in real time. In an embodiment of the present application, during the high-voltage power-on processing and the high-voltage power-off processing, the main control module of the BMS can determine the state of the positive switch in each battery pack circuit by detecting the voltage at the positive switch detection point on each detection circuit. The main control module of the BMS may include a high-voltage acquisition unit and a main control diagnostic unit. The high-voltage acquisition unit can be used to acquire the voltage between the switch detection points in the circuit. The main control diagnostic unit can be used to control the closing and opening of the switch, as well as to obtain the voltage collected by the high-voltage acquisition unit, and diagnose the state of the high-voltage switch based on the voltage collected by the high-voltage acquisition unit.

[0082] The first battery pack circuit may be the battery pack circuit containing a battery pack whose total voltage is greater than that of another battery pack. Before controlling the battery packs to enter the high-voltage power-up process, the total voltages of the two battery packs may be obtained and compared, so that the battery pack whose total voltage is greater than that of the other battery pack (i.e., the first battery pack) undergoes the high-voltage power-up process first. While the first battery pack enters the high-voltage power-up process, a status diagnosis may be performed on each high-voltage switch in the first battery pack circuit. After the first battery pack circuit is powered on, the second battery pack is controlled to enter the high-voltage power-up process, and a status diagnosis may be performed on each high-voltage switch in the second battery pack circuit.

[0083] In an embodiment of the present application, by controlling the battery pack with a larger total voltage to enter the high-voltage power-on process first, it is helpful to prevent the positive switch of the other battery pack circuit from being damaged due to the voltage difference when the other battery pack with a smaller total voltage enters the high-voltage power-on process.

[0084] In order to enable those skilled in the art to better understand the embodiments of the present application, the embodiments of the present application are described below using an example:

[0085] Taking FIG. 7 as an example, an embodiment of the present application provides a method for controlling a first battery pack circuit and a second battery pack circuit to perform high voltage power-up processing and status diagnosis.

[0086] Wherein, the total voltage V of the first battery pack Pack1 is determined bate1 Is it greater than the total voltage V of the second battery pack Pack2? bate2 ;

[0087] If V bate1 Greater than V bate2 , the first battery pack Pack1 enters the high voltage power-up process first.

[0088] It should be noted that if the total voltages of packs 1 and 2 are detected to be the same before the high-voltage relay is closed, the system will first power on the first battery pack Pack1 at high voltage, and then power on the first battery pack Pack2 at high voltage.

[0089] For the first battery pack Pack1, the high-voltage power-on sequence is as follows: first close the main negative relay K3 (the main negative relay K3 and MOS are opened and closed at the same time), then close the pre-charge relay K2, and finally close the main positive relay K1. When the main positive relay K1 is closed, disconnect the pre-charge relay K2.

[0090] The first battery pack Pack1 determines the state of the first main negative relay by collecting the voltage of the negative switch detection point 6 on the first detection circuit.

[0091] Among them, before the main negative relay K3 is closed, the voltage of the negative pole switch detection point 6 is 5V. After the main negative relay K3 is closed, the voltage of the negative pole switch detection point 6 is 1.67V. That is: if the voltage of the negative pole switch detection point 6 is 5V, the state of the first main negative relay K3 is determined to be disconnected; if the voltage of the negative pole switch detection point 6 is 1.67V, the state of the first main negative relay K3 is determined to be closed.

[0092] The first battery pack Pack1 collects a first voltage between the positive switch detection point 3 and the positive switch detection point 4, collects a second voltage between the positive switch detection point 4 and the positive switch detection point 5, calculates a first difference between the first voltage and the second voltage, and determines the state of the first main positive relay based on the first difference.

[0093] Among them, before the main positive relay K1 is closed, the first difference is greater than 100V, and after the main positive relay K1 is closed, the first difference is less than 10V. That is: if the collected first difference is greater than 100V, the state of the main positive relay K1 is determined to be disconnected; if the collected first difference is less than 10V, the state of the main positive relay K1 is determined to be closed.

[0094] After the first battery pack Pack1 is powered on, the system monitors the total voltage difference between the first battery pack Pack1 and the second battery pack Pack2 in real time. When the total voltage difference between the two packs is less than a certain value, such as 5V, the second battery pack Pack2 is powered on with high voltage.

[0095] The high voltage power-on sequence for the second battery pack Pack2 is: first close the main positive relay K1, and then close the main negative relay K3.

[0096] It should be noted here that when the second battery pack Pack2 is powered on at high voltage, there is no need to close the pre-charge relay K2. The reason for not closing the pre-charge relay K2 is that due to the presence of the first battery pack Pack1, the external load is already in a high-voltage state and the pressure difference between the two packs is small, which will not cause damage to the high-voltage relay in the second battery pack Pack2.

[0097] The second battery pack Pack2 collects the first voltage between the positive switch detection point 3 and the positive switch detection point 4, collects the second voltage between the positive switch detection point 4 and the positive switch detection point 5, calculates the second difference between the first voltage and the second voltage, and determines the state of the second main positive relay based on the second difference.

[0098] Among them, before the main positive relay K1 is closed, the first difference is greater than 30V, and after the main positive relay K1 is closed, the second difference is less than 10V. That is: if the collected second difference is greater than 30V, the state of the main positive relay K1 is determined to be disconnected; if the collected second difference is less than 10V, the state of the main positive relay K1 is determined to be closed.

[0099] The second battery pack Pack2 determines the state of the second main negative relay by collecting the voltage of the negative switch detection point 6 on the second detection circuit.

[0100] Among them, before the main negative relay K3 is closed, the voltage of the negative pole switch detection point 6 is 2.5V, and after the main negative relay K3 is closed, the voltage of the negative pole switch detection point 6 is 1.67V. That is: if the voltage of the negative pole switch detection point 6 is 2.5V, the state of the second main negative relay K3 is determined to be disconnected; if the voltage of the negative pole switch detection point 6 is 1.67V, the state of the second main negative relay K3 is determined to be closed.

[0101] The embodiments of the present application provide a method for controlling a first battery pack circuit and a second battery pack circuit to perform high voltage power-down processing and perform switch detection of a high voltage battery pack.

[0102] Assuming that the two packs are powered off in a certain order, the first battery pack Pack1 is powered off first, and the second battery pack Pack2 is powered off later. It should be noted that in an emergency situation of the vehicle, such as a collision, the two packs may need to be powered off at the same time. The diagnostic method for powering off the two packs at the same time is consistent with the traditional single pack power-off diagnostic method and is simple, so this application will not give a detailed introduction.

[0103] When the first battery pack Pack1 is powered off, the main negative relay K3 is disconnected first, and then the main positive relay K1 is disconnected.

[0104] The first battery pack Pack1 determines the state of the first main negative relay by collecting the voltage of the negative switch detection point 6 on the first detection circuit.

[0105] Before the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 1.67 V. After the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 2.5 V. In other words, if the voltage at the negative switch detection point 6 is 1.67 V, the state of the first main negative relay K3 is determined to be closed. If the voltage at the negative switch detection point 6 is 2.5 V, the state of the first main negative relay K3 is determined to be open.

[0106] The first battery pack Pack1 collects a first voltage between the positive switch detection point 3 and the positive switch detection point 4, collects a second voltage between the positive switch detection point 4 and the positive switch detection point 5, calculates a first difference between the first voltage and the second voltage, and determines the state of the first main positive relay based on the first difference.

[0107] Among them, before the main positive relay K1 is disconnected, the first difference is less than 10V, and after the main positive relay K1 is disconnected, the first difference is greater than 30V. That is: if the collected first difference is less than 10V, the state of the main positive relay K1 is determined to be closed; if the collected first difference is greater than 30V, the state of the main positive relay K1 is determined to be disconnected.

[0108] After the first battery pack Pack1 is powered off, the second battery pack Pack2 is powered off. When the second battery pack Pack2 is powered off, the main negative relay K3 is first disconnected, and then the main positive relay K1 is disconnected.

[0109] The second battery pack Pack2 determines the state of the second main negative relay by collecting the voltage of the negative switch detection point 6 on the second detection circuit.

[0110] Before the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 2.5V. After the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 5V. In other words, if the voltage at the negative switch detection point 6 is 2.5V, the state of the second main negative relay K3 is determined to be closed. If the voltage at the negative switch detection point 6 is 5V, the state of the second main negative relay K3 is determined to be open.

[0111] The second battery pack Pack2 collects the first voltage between the positive switch detection point 3 and the positive switch detection point 4, collects the second voltage between the positive switch detection point 4 and the positive switch detection point 5, calculates the second difference between the first voltage and the second voltage, and determines the state of the second main positive relay based on the second difference.

[0112] Among them, before the second main positive relay K1 is disconnected, the first difference is less than 10V, and after the main positive relay K1 is disconnected, the first difference is greater than 100V. That is: if the collected first difference is less than 10V, the state of the main positive relay K1 is determined to be closed; if the collected first difference is greater than 100V, the state of the main positive relay K1 is determined to be disconnected.

[0113] According to the above-mentioned dual-pack high-voltage power-on and power-off process, the specific embodiment of the present application accurately judges the status of each relay through the closing timing and high-voltage sampling characteristics of each relay, that is: through the circuit set in the embodiment of the present application and in conjunction with the different closing timings of each relay, the status of each relay in the dual-pack power-on and power-off process is accurately judged.

[0114] An embodiment of the present application also provides an electric vehicle, comprising: a processor, a memory, and a computer program stored in the memory and capable of running on the processor. When the computer program is executed by the processor, the various processes of the method embodiment described above are implemented and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0115] An embodiment of the present application further provides an electric vehicle, comprising the switch detection circuit of the high-voltage battery pack as described above.

[0116] The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also be aware that the actions and modules involved in the description are not necessarily required for this application. In addition, it is understood that the steps in the method of the embodiment of the present application can be adjusted in sequence, merged and deleted according to actual needs, and the modules in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0117] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0118] Alternatively, the present application can also be implemented as a non-transitory machine-readable storage medium (or computer-readable storage medium, or machine-readable storage medium) on which executable code (or computer program, or computer instruction code) is stored. When the executable code (or computer program, or computer instruction code) is executed by a processor of an electronic device (or electronic device, server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0119] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the application herein may be implemented as electronic hardware, computer software, or combinations of both.

[0120] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems and methods according to multiple embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or code, and the part of the module, program segment or code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0121] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A switch detection circuit for a high voltage battery pack, characterized in that: It includes at least two detection circuits, each of which is arranged between the negative electrode of a high-voltage battery pack and the load or power supply; Wherein, the negative electrode switch of the high-voltage battery pack is connected in parallel with the detection circuit, and the positive electrode switch of the high-voltage battery pack is connected in series between the positive electrode of the high-voltage battery pack and the load or power supply; The detection circuit is provided with a negative switch detection point, which is used to detect a detection voltage of the negative switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the negative switch based on the detection voltage; A positive switch detection point is provided between the positive electrode of the high-voltage battery pack and the load or power supply, which is used to detect the detection voltage of the positive switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the positive switch based on the detection voltage.

2. The switch detection circuit of the high-voltage battery pack according to claim 1 is characterized in that , the detection circuit includes a low voltage power supply, a voltage divider circuit and a current divider circuit, wherein: The voltage divider circuit is connected between the low voltage power supply and the load or power supply, and the negative switch detection point is set at the voltage divider point of the voltage divider circuit; The shunt circuit is connected between the negative pole switch detection point and the negative pole of the high-voltage battery pack. When the negative pole switch is closed, the shunt circuit is a passage, and when the negative pole switch is disconnected, the shunt circuit is an open circuit.

3. The switch detection circuit of the high-voltage battery pack according to claim 2, characterized in that: The voltage divider circuit includes a first resistor and a second resistor, and the current divider circuit includes a third resistor and a first switch tube; The first resistor and the second resistor are connected in series between the low-voltage power supply and the load or power supply, the negative switch detection point is set between the first resistor and the second resistor, and the third resistor and the first switch tube are connected in series between the negative switch detection point and the negative electrode of the high-voltage battery pack.

4. The switch detection circuit of the high-voltage battery pack according to claim 3, characterized in that: The first end of the third resistor is connected to the negative electrode of the high-voltage battery pack, the second end of the third resistor is connected in parallel to the first end of the first resistor and the first end of the second resistor through the first switch tube, the first end of the first resistor is connected in series with the first end of the second resistor, the second end of the first resistor is connected to the low-voltage power supply, and the second end of the second resistor is connected to the load or power supply.

5. The switch detection circuit of the high-voltage battery pack according to claim 1, characterized in that: The positive switch detection point provided between the positive electrode of the high-voltage battery pack and the load or power supply includes: a first positive switch detection point provided between the positive electrode of the high-voltage battery pack and the positive switch, and a second positive switch detection point provided between the positive switch and the load or power supply; A third positive switch detection point is provided between the negative electrode of the high-voltage battery pack and the negative electrode switch; The first positive switch detection point, the second positive switch detection point and the third positive switch detection point The point is used to detect a detection voltage of the positive switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the positive switch based on the detection voltage.

6. The switch detection circuit of the high-voltage battery pack according to claim 1, characterized in that: The negative switch includes a main negative relay, the detection circuit includes a first switch tube, and the positive switch includes a main positive relay and a pre-charge relay; Wherein, when the first high-voltage battery pack and the second high-voltage battery pack are powered on, the main negative relay and the first switch tube in the first high-voltage battery pack are closed first, the pre-charge relay is closed second, and the main positive relay is closed last; The main positive relay in the second high-voltage battery pack is closed first, and then the main negative relay and the first switch tube are closed, and the pre-charging relay is not closed.

7. The switch detection circuit of the high-voltage battery pack according to claim 1, characterized in that: The negative switch includes a main negative relay, the detection circuit includes a first switch tube, and the positive switch includes a main positive relay and a pre-charge relay; When the first high-voltage battery pack and the second high-voltage battery pack are powered off, the main negative relay in the first high-voltage battery pack is disconnected first, and then the main positive relay is disconnected; The main negative relay in the second high-voltage battery pack is disconnected first, and then the main positive relay is disconnected.

8. A switch detection method for a high-voltage battery pack, characterized in that: include: Acquire voltage information of at least two high-voltage battery packs, the at least two high-voltage battery packs comprising a first high-voltage battery pack and a second high-voltage battery pack; wherein a detection circuit is provided between a negative electrode of each high-voltage battery pack and a load or a power source, the detection circuit is provided with a negative electrode switch detection point, and a positive electrode switch detection point is provided between a positive electrode of each high-voltage battery pack and the load or the power source; Determining a power-on or power-off sequence of the first high-voltage battery pack and the second high-voltage battery pack according to voltage information of the at least two high-voltage battery packs; When the first high-voltage battery pack is powered on or off, the positive switch and the negative switch of the first high-voltage battery pack are controlled to be closed or opened according to a preset first execution sequence, the detection voltage of the negative switch is detected through the negative switch detection point, and the state of the negative switch is determined based on the detection voltage; the detection voltage of the positive switch is detected through the positive switch detection point, and the state of the positive switch is determined based on the detection voltage; When the second high-voltage battery pack is powered on or off, the positive switch and the negative switch of the second high-voltage battery pack are controlled to be closed or opened according to a preset second execution order, the detection voltage of the negative switch is detected by the negative switch detection point, and the state of the negative switch is determined based on the detection voltage; the detection voltage of the positive switch is detected by the positive switch detection point, and the state of the positive switch is determined based on the detection voltage.

9. The method according to claim 8, characterized in that When the first high-voltage battery pack and the second high-voltage battery pack are powered on, the negative switch is closed before the positive switch in the first execution sequence; and the positive switch is closed before the negative switch in the second execution sequence.

10. The method according to claim 8, characterized in that When the first high-voltage battery pack and the second high-voltage battery pack are powered off, the negative switch is disconnected before the positive switch in the first execution sequence; and the negative switch is disconnected before the positive switch in the second execution sequence.

11. The method according to any one of claims 8 to 10, characterized in that: The step of determining a power-on sequence of the first high-voltage battery pack and the second high-voltage battery pack according to voltage information of the at least two high-voltage battery packs includes: According to the voltage information of the first high-voltage battery pack being greater than the voltage information of the second high-voltage battery pack, it is determined that the first high-voltage battery pack has a priority in being powered on over the second high-voltage battery pack.

12. The method according to any one of claims 8 to 10, characterized in that The negative switch includes a main negative relay, the detection circuit includes a first switch tube, and the positive switch includes a main positive relay and a pre-charge relay; When the first high-voltage battery pack and the second high-voltage battery pack are powered on, controlling the positive switch and the negative switch of the first high-voltage battery pack to close according to a preset first execution sequence includes: For the first high-voltage battery pack, first close the main negative relay and the first switch tube, then close the pre-charge relay, and finally close the main positive relay; The controlling the positive switch and the negative switch of the second high-voltage battery pack to close according to a preset second execution sequence includes: For the second high-voltage battery pack, the main positive relay is closed first, and then the main negative relay and the first switch tube are closed, and the pre-charging relay is not closed.

13. The method according to any one of claims 8 to 10, characterized in that The negative switch includes a main negative relay, the detection circuit includes a first switch tube, and the positive switch includes a main positive relay and a pre-charge relay; When the first high-voltage battery pack and the second high-voltage battery pack are powered off, controlling the positive switch and the negative switch of the first high-voltage battery pack to be disconnected according to a preset first execution sequence includes: For the first high-voltage battery pack, first disconnect the main negative relay, and then disconnect the main positive relay; The controlling the positive switch and the negative switch of the second high-voltage battery pack to be disconnected according to a preset second execution sequence includes: For the second high-voltage battery pack, the main negative relay is disconnected first, and then the main positive relay is disconnected.

14. The method according to any one of claims 8 to 10, characterized in that The positive switch detection point provided between the positive electrode of each high-voltage battery pack and the load or power supply includes: a first positive switch detection point provided between the positive electrode of each high-voltage battery pack and the positive switch, and a second positive switch detection point provided between the positive switch and the load or power supply; A third positive switch detection point is provided between the negative electrode of each high-voltage battery pack and the negative electrode switch; The first positive switch detection point, the second positive switch detection point and the third positive switch detection point are used to detect the detection of the positive switch when the high-voltage battery pack is in a power-on or power-off state. A voltage is measured, and a state of the positive switch is determined based on the detected voltage.

15. An electric vehicle, characterized in that: include: A processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein the computer program implements the method according to any one of claims 8 to 14 when executed by the processor.

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