WO2025000883A1 - Switch testing circuit and testing method for high-voltage battery packs, and electric vehicle - Google Patents

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

Switch detection circuit, detection method and electric vehicle of high voltage battery pack

This application claims the priority of 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”, all contents of which are incorporated by reference in this application.

Technical Field

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

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.

In the related art, most of them are solutions 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 dual battery packs) connected in parallel.

Summary of the invention

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.

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

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.

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

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. A third aspect of the present application provides an electric vehicle, including: 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 described above when executed by the processor.

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

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

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

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.

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

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.

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

FIG2 is a schematic diagram of the structure of a switch detection circuit of a high-voltage battery pack shown in an embodiment of the present application;

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

FIG4 is another specific structural diagram of a switch detection circuit of a high-voltage battery pack shown in an embodiment of the present application;

FIG5 is another specific structural diagram of a switch detection circuit of a high-voltage battery pack shown in an embodiment of the present application;

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;

FIG. 7 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

The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, 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.

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

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 the same type of information 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, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

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 and then the pre-charge relay, and then the main positive relay, and finally the pre-charge relay is disconnected after the main positive relay is closed; the power-off sequence of a single battery pack is to disconnect the main positive relay first and then the main negative relay. In the related art, regardless of whether the high-voltage relay is disconnected or closed, the diagnostic method is consistent, that is: the state of the main positive relay is judged by the difference between V _AB and V _BC before and after closing and disconnecting, and the state of the main negative relay is judged by the voltage of V _BD before and after closing and disconnecting.

The applicant found in the research that in order to provide more power and more energy to the vehicle, 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 used to diagnose the status of the high-voltage relay in a system of multiple battery packs in parallel, when a battery pack circuit is powered on, the negative The load end is in a high voltage state at this time, and the high voltage sampling of another 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 a multi-battery pack parallel system.

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.

The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

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

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, so that 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.

Referring to FIG3, FIG3 is a schematic diagram of the switch detection circuit structure of the high-voltage battery pack shown in an embodiment of the present application. As shown in FIG3, the switch detection circuit of the high-voltage battery pack provided in 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 a negative electrode switch detection point (P1 and P2), which is used to detect the detection voltage of the negative electrode switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the negative electrode switch based on the detection voltage; a positive electrode switch detection point (1, 3 and 4, 6) is provided between the positive electrode of the high-voltage battery pack and the load or power supply, and a positive electrode switch detection point (2 and 5) is provided between the negative electrode of the high-voltage battery pack and the negative electrode switch, which is used to detect the detection voltage of the positive electrode switch when the high-voltage battery pack is in a power-on or power-off state, and determine the state of the positive electrode switch based on the detection voltage.

As shown in FIG3 , 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 pole output terminal (+) of the first battery pack and the first positive pole switch, a positive pole switch detection point 2 is provided between the negative pole output terminal (-) of the first battery pack and the first negative pole switch, and a positive pole switch detection point 3 is provided between the positive pole 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 pole output terminal (+) of the second battery pack and the second positive pole switch, and a positive pole switch detection point 5 is provided between the positive pole output terminal (-) of the second battery pack and the second positive pole switch. A positive switch detection point 5 is set between the negative output terminal (-) of the second battery pack and the second negative switch, and a positive switch detection point 6 is set between the second positive switch and the high voltage positive terminal (P+).

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.

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 switch 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 switch 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.

In a specific embodiment, as shown in FIG5 , the first end of the third resistor R3 is connected to the negative electrode of the high-voltage battery pack, 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 switch and the first switch tube MOS1 are opened and closed at the same time.

In a specific embodiment, as shown in FIGS. 2-5 , 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 provided between the negative electrode of the high-voltage battery pack and the negative 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 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. 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 the 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.

An embodiment of the present application provides a switch detection circuit of a high-voltage battery pack, comprising at least two detection circuits, each of which is arranged between a negative electrode of a high-voltage battery pack and a load or a power source; 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 the power source; the detection circuit is provided with a negative electrode switch detection point for detecting a detection voltage of the negative electrode switch when the high-voltage battery pack is in a power-on or power-off state, and determining the state of the negative electrode switch based on the detection voltage; a positive electrode switch detection point is provided between the positive electrode of the high-voltage battery pack and the load or the power source, for The detection voltage of the positive switch when the high-voltage battery pack is in a power-on or power-off state is detected, and the state of the positive switch is determined based on the detection voltage. The technical solution of the present application is provided with a detection circuit in parallel on each negative switch, and the state of each negative switch is diagnosed by detecting the detection voltage of the negative switch detection point provided in the detection circuit, and the state of each positive switch is diagnosed by detecting the detection voltage of the positive switch detection point provided on the positive switch, which solves the problem that the state of high-voltage switches of multiple battery packs cannot be diagnosed in the related art.

Referring to FIG. 6 , an embodiment of the present application provides a switch detection method for a high-voltage battery pack, the method comprising:

S601: Acquire voltage information of at least two high-voltage battery packs, wherein the at least two high-voltage battery packs include 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;

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;

S603: 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;

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.

In a specific embodiment, the first battery pack circuit and the second battery pack circuit may include a plurality of high-voltage relays, respectively. For a high-voltage circuit with two battery packs connected in parallel, after the first battery pack circuit is closed and powered on, the high voltage generated will cause the second battery pack circuit that is not closed and powered on to generate high voltage, thereby affecting the high-voltage sampling of the second battery pack circuit; when diagnosing based on the high-voltage sampling of the second battery pack circuit, the diagnosis result of the high-voltage relay fault state will be inaccurate, and it will be impossible to accurately determine whether each high-voltage relay of the second battery pack circuit is effectively controlled.

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.

Wherein, 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 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.

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 may apply the method to the switch detection circuit of the high-voltage battery pack in actual applications.

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.

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, and those skilled in the art may adopt other battery pack circuit structures, which are not limited in the present application.

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.

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.

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.

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:

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.

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;

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.

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;

When the first high-voltage battery pack and the second high-voltage battery pack are powered off, The 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.

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 of the detection point 6 is 5V, and after the main negative relay K3 is closed, the voltage of the first detection point P1, i.e., the detection point 6, is 1.67V. In other words, if the voltage of the detection point 6 is detected to be 5V, it can be determined that the main negative relay K3 is in an open state; if the voltage of the detection point 6 is detected to be 1.67V, it means that the main negative relay K3 is in a 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 of 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.

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 the detection point 6 is 2.5V, and after the main negative relay K3 is closed, the voltage at the detection point 6 is 1.67V. In other words, if the voltage at the detection point 6 is detected to be 2.5V, it can be determined that the main negative relay K3 is in an open state; if the voltage at the detection point 6 is detected to be 1.67V, it means that the main negative relay K3 is in a closed state. In the embodiment of the present application, the front end of the main negative relay K3 is equivalent to the earth, so when the main negative relay K3 of the first battery pack circuit is closed, the two packs are connected in parallel, so the second resistor R2 of the second battery pack circuit is now connected to the earth, and the two identical resistors divide the 5V, 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, and the voltage of the second resistor R2 and the third resistor R3 in parallel and in series with the second resistor R1 is measured, so the second voltage value V2 = 1.67 V. 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.

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 disconnected, the voltage at the detection point 6 is 1.67V, and after the main negative relay K3 is disconnected, the voltage at the detection point 6 is 2.5V. In other words, if the voltage at the detection point 6 is detected to be 1.67V, it can be determined that the main negative relay K3 is in a closed state; if the voltage at the detection point 6 is detected to be 2.5V, it means that the main negative relay K3 is in an open state. 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.

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 disconnected, the voltage at the detection point 6 is 2.5V, and after the main negative relay K3 is disconnected, the voltage at the detection point 6 is 5V. That is, if the voltage at the detection point 6 is detected to be 2.5V, If the voltage at the detection point 6 is 5V, it means that the main negative relay K3 is in the open state. It should be noted that the voltage value to be determined can be set according to the resistance in the system, which is not specifically limited here.

It should be noted that, in a specific embodiment, as shown in FIG7 , 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, it means that the main positive relay K1 is in an open state; when |V25-V45|<10V is detected, it means that the main positive relay K1 is in a closed state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

It should be noted that, in a specific embodiment, as shown in FIG7 , 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, it means that the main positive relay K1 is in an open state; when |V25-V45|<10V is detected, it means that the main positive relay K1 is in a closed state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

It should be noted that, in a specific embodiment, as shown in FIG7 , 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, it means that the main positive relay K1 is in a closed state; when |V25-V45|>30V is detected, it means that the main positive relay K1 is in a disconnected state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

It should be noted that, in a specific embodiment, as shown in FIG7 , for the second battery pack circuit, before the main positive relay K1 is disconnected, |V25-V45|<10V, and after the K1 main positive relay is disconnected, |V25-V45|>100V. In other words, when |V25-V45|<10V is detected, it means that the main positive relay K1 is in a closed state; when |V25-V45|>100V is detected, it means that the main positive relay K1 is in a disconnected state. It should be noted that the judgment threshold can be set according to the system and is not specifically limited here.

BMS (Battery Management System) is an important link between on-board power batteries and electric vehicles, 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.

The first battery pack circuit may be a battery pack circuit where a battery pack having a total voltage greater than that of another battery pack is located. Before controlling the battery pack to enter the high voltage power-on process, the total voltages of the two battery packs may be obtained for comparison, so that the battery pack having a total voltage greater than that of the other battery pack (i.e. When the first battery pack enters the high-voltage power-on process, the status of each high-voltage switch in the first battery pack circuit can be diagnosed. When the first battery pack circuit is powered on, the second battery pack is controlled to enter the high-voltage power-on process, and the status of each high-voltage switch in the second battery pack circuit is diagnosed.

In the 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.

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 by using an example:

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.

Wherein, determining whether the total voltage V _bate1 of the first battery pack Pack1 is greater than the total voltage V _bate2 of the second battery pack Pack2;

If V _bate1 is greater than V _bate2 , the first battery pack Pack1 enters the high voltage power-up process first.

It should be noted that if the total voltages of pack 1 and pack 2 are detected to be consistent before the high-voltage relay is closed, the system preferentially powers up the first battery pack Pack1 with high voltage, and then powers up the first battery pack Pack2 with high voltage.

The high-voltage power-on sequence for the first battery pack Pack1 is: 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.

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.

Among them, before the main negative relay K3 is closed, the voltage of the negative switch detection point 6 is 5V, and after the main negative relay K3 is closed, the voltage of the negative switch detection point 6 is 1.67V, that is: if the voltage of the negative switch detection point 6 is 5V, the state of the first main negative relay K3 is determined to be disconnected, and if the voltage of the negative switch detection point 6 is 1.67V, the state of the first main negative relay K3 is determined to be closed.

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 according to the first difference.

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, and if the collected first difference is less than 10V, the state of the main positive relay K1 is determined to be closed.

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.

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.

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 existence 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.

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 according to the second difference.

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, and if the collected second difference is less than 10V, the state of the main positive relay K1 is determined to be closed.

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.

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

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.

Assuming that there is a sequence for powering off the two packs, 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, etc., both packs may need to be powered off at the same time. The diagnostic method for powering off both packs at the same time is consistent with the traditional single-pack power-off diagnostic method and is simple, and this application will not give a detailed introduction.

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.

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.

Before the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 1.67 V, and after the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 2.5 V. That is, 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, and 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.

The first battery pack Pack1 collects a first voltage between the positive switch detection point 3 and the positive switch detection point 4, and collects a second voltage between the positive switch detection point 4 and the positive switch detection point 5. voltage, calculating a first difference between the first voltage and the second voltage, and determining a state of the first main positive relay according to the first difference.

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, and if the collected first difference is greater than 30V, the state of the main positive relay K1 is determined to be disconnected.

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 disconnected first, and then the main positive relay K1 is disconnected.

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.

Before the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 2.5 V, and after the main negative relay K3 is disconnected, the voltage at the negative switch detection point 6 is 5 V. That is, if the voltage at the negative switch detection point 6 is 2.5 V, the state of the second main negative relay K3 is determined to be closed, and if the voltage at the negative switch detection point 6 is 5 V, the state of the second main negative relay K3 is determined to be open.

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 according to the second difference.

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, and if the collected first difference is greater than 100V, the state of the main positive relay K1 is determined to be disconnected.

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 state 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 state of each relay in the dual-pack power-on and power-off process is accurately judged.

An embodiment of the present application also provides an electric vehicle, including: 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 described here.

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

The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the description of each embodiment has its own emphasis. For the part that is not described in detail in a certain embodiment, refer to the relevant description of other embodiments. Those skilled in the art should also know that the actions and modules involved in the description are not necessarily required for the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application can be adjusted in order, 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.

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.

Alternatively, the present application can also be implemented as a non-temporary 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.

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.

The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system and method according to multiple embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a part of a module, a program segment or a code, and the part of the module, the program segment or the 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 square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square 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 square box in the block diagram and/or the flow chart, and the combination of the square boxes in the block diagram and/or the 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.

The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (15)

A switch detection circuit of a high-voltage battery pack, characterized in that it comprises at least two detection circuits, each of which is arranged between a negative electrode of a high-voltage battery pack and a load or a power source; 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. The switch detection circuit of the high-voltage battery pack according to claim 1 is characterized in that the detection circuit comprises a low-voltage power supply, a voltage divider circuit and a current shunt 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. The switch detection circuit of the high-voltage battery pack according to claim 2 is characterized in that the voltage divider circuit includes a first resistor and a second resistor, and the current shunt 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. The switch detection circuit of the high-voltage battery pack according to claim 3 is 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. The switch detection circuit of the high-voltage battery pack according to claim 1 is 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. The switch detection circuit of the high-voltage battery pack according to claim 1 is 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. The switch detection circuit of the high-voltage battery pack according to claim 1 is 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. A switch detection method for a high-voltage battery pack, characterized by comprising: 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. The method according to claim 8 is 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. The method according to claim 8 is characterized in that, when the first high-voltage battery pack and the second high-voltage battery pack are powered off, the negative electrode in the first execution sequence The switch is disconnected before the positive switch; in the second execution sequence, the negative switch is disconnected before the positive switch. The method according to any one of claims 8 to 10, characterized in that 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 comprises: 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. 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. 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. 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. An electric vehicle, characterized in that it comprises: a processor, a memory, and a computer program stored in the memory and capable of running on the processor, wherein when the computer program is executed by the processor, the method according to any one of claims 8 to 14 is implemented.