Negative electrode isolation circuit, battery total voltage acquisition circuit and acquisition method

Abstract

The application discloses a negative electrode isolation circuit, a battery total voltage acquisition circuit and an acquisition method. The negative electrode isolation circuit comprises, in series, a high-voltage acquisition chip, a sampling current-limiting resistor, a high-voltage diode, a first negative electrode voltage division sampling resistor, a total negative relay and a protection resistor. The high-voltage acquisition chip is connected in parallel with the second negative electrode voltage division sampling resistor after being connected in series with the sampling current-limiting resistor. The first end of the high-voltage acquisition chip is connected with a voltage terminal, and the second end of the high-voltage acquisition chip is grounded. The total negative relay is connected with the negative electrode of a battery pack. The high-voltage acquisition chip is arranged to judge the state of the total negative relay, and the external impedance loop is cut off, so that the other total voltage acquisition circuits of the battery pack cannot form a complete voltage division circuit with the external circuit, some false fault judgments are avoided, the acquisition accuracy of the battery total voltage is improved, the reliability of the battery system is improved, and the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of circuit technology, and in particular relates to a negative electrode isolation circuit, a battery total voltage acquisition circuit and an acquisition method. Background Art

[0002] At present, battery total voltage collection is a basic function of the battery management system. It mainly collects battery voltage and monitors the status of the battery's total voltage, and can perform corresponding overvoltage and undervoltage protection. It can also collect the voltage before and after the relay to determine whether the relay is in a fault state and whether the pre-charge function is successful.

[0003] Currently, the primary method for collecting total battery voltage is to use resistor dividers to reduce the voltage to a range that can be properly acquired by the acquisition chip. When collecting multiple battery total voltages, the impedance of each total voltage acquisition circuit and the impedance of the external circuit form a voltage divider circuit, causing abnormal battery total voltage acquisition and, consequently, misjudging the battery and relay status. Summary of the Invention

[0004] Based on this, the present invention proposes a negative electrode isolation circuit, a battery total voltage acquisition circuit and an acquisition method to solve the above technical problems.

[0005] The negative electrode isolation circuit provided by the present invention includes a high-voltage acquisition chip, a sampling current-limiting resistor, a high-voltage diode, a first negative electrode voltage-dividing sampling resistor, a total negative relay and a protection resistor connected in series in sequence. The high-voltage acquisition chip is connected in series with the sampling current-limiting resistor and then connected in parallel with the second negative electrode voltage-dividing sampling resistor. The first end of the high-voltage acquisition chip is connected to the voltage end, the second end of the high-voltage acquisition chip is grounded, and the total negative relay is connected to the negative electrode of the battery pack.

[0006] As a further improvement of the present invention, the resistance value of the first negative electrode voltage-dividing sampling resistor is equal to the resistance value of the second negative electrode voltage-dividing sampling resistor.

[0007] As a further improvement of the present invention, the input voltage of the voltage terminal is 5V.

[0008] The present invention also provides a battery total voltage acquisition circuit, comprising the above-mentioned negative electrode isolation circuit and a positive electrode sampling circuit, wherein the positive electrode sampling circuit is connected to the positive electrode of the battery pack, and the positive electrode sampling circuit comprises a first positive electrode sampling circuit, a second positive electrode sampling circuit, and a third positive electrode sampling circuit connected in parallel, and a first resistor is connected in series between the positive electrode of the battery pack and the negative electrode of the battery pack.

[0009] As a further improvement of the present invention, the first positive sampling circuit includes a first positive sampling resistor and a total positive relay, the first positive sampling resistor and the total positive relay are connected in series, the first positive sampling resistor is connected to the negative electrode of the battery pack, and the total positive relay is connected to the positive electrode of the battery pack.

[0010] As a further improvement of the present invention, the second positive sampling circuit includes a second positive sampling resistor and a charging relay, the second positive sampling resistor and the charging relay are connected in series, the second positive sampling resistor is connected to the negative electrode of the battery pack, and the charging relay is connected to the positive electrode of the battery pack.

[0011] As a further improvement of the present invention, the third positive sampling circuit includes a third positive sampling resistor and a heating relay, the third positive sampling resistor and the heating relay are connected in series, the third positive sampling resistor is connected to the negative electrode of the battery pack, and the heating relay is connected to the positive electrode of the battery pack.

[0012] As a further improvement of the present invention, a pre-charging relay and a pre-charging resistor are connected in parallel at both ends of the total positive relay, and the pre-charging relay and the pre-charging resistor are connected in series.

[0013] The present invention also provides a battery total voltage acquisition method, which is implemented based on the above-mentioned battery total voltage acquisition circuit. The method includes the following steps:

[0014] Determining the working state of the total negative relay according to the voltage collected by the high-voltage collection chip;

[0015] collecting a voltage across the first resistor as a first voltage;

[0016] collecting a voltage at one end of the first positive sampling resistor connected to the total positive relay as a second voltage, and determining whether the second voltage is equal to the first voltage; if so, the total positive relay or the pre-filling relay is adhered; otherwise, the total positive relay or the pre-filling relay is normal;

[0017] collecting a voltage at one end of the second positive sampling resistor connected to the charging relay as a third voltage, and determining whether the third voltage is equal to the first voltage; if so, the charging relay is stuck; otherwise, the charging relay is normal;

[0018] The voltage of one end of the third positive sampling resistor connected to the heating relay is collected as a fourth voltage, and it is determined whether the fourth voltage is equal to the first voltage. If they are equal, the heating relay is stuck; otherwise, the heating relay is normal.

[0019] As a further improvement of the present invention, judging the working state of the total negative relay according to the voltage collected by the high-voltage collection chip specifically includes:

[0020] The working state of the total negative relay is determined based on whether the voltage collected by the high-voltage collection chip is the voltage terminal input voltage or half of the voltage terminal input voltage;

[0021] If the voltage is input to the voltage terminal, the total negative relay is normal. If it is half of the voltage input to the voltage terminal, the total negative relay is stuck.

[0022] Compared with the prior art, the present invention provides a negative electrode isolation circuit, a battery total voltage acquisition circuit, and an acquisition method. The present invention sets a high-voltage acquisition chip. The voltage collected by the high-voltage acquisition chip determines the on / off state of the total negative relay, without referring to the positive electrode voltage of the battery pack. The negative electrode total voltage acquisition is isolated from other total voltage acquisition circuits, avoiding the formation of a voltage divider circuit by multiple total voltage acquisition circuits and an external circuit, and cutting off the formation of an equivalent impedance of the external circuit. The high-voltage acquisition chip is set to determine the state of the total negative relay and cut off the external impedance circuit, ensuring that other total voltage acquisition circuits cannot form a complete voltage divider circuit with the external impedance circuit, thereby avoiding some erroneous fault judgments, improving the acquisition accuracy of the battery total voltage, and thus improving the reliability of the battery system and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only part of the embodiments of the present invention, rather than all the embodiments. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings are all within the scope of protection of this application.

[0024] Figure 1 is a circuit diagram of a negative electrode isolation circuit provided by an embodiment of the present invention;

[0025] Figure 2 This is a circuit schematic diagram of a battery total voltage acquisition circuit provided by an embodiment of the present invention;

[0026] Figure 3 This is a circuit schematic diagram of a battery total voltage acquisition circuit provided by an embodiment of the present invention;

[0027] Figure 4 This is a flow chart of a battery total voltage collection method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] In order to make the description of the present disclosure more detailed and complete, the following is an illustrative description of the implementation methods and specific examples of the present invention; however, this is not the only form of implementing or using the specific embodiments of the present invention. The implementation methods cover the features of multiple specific embodiments and the method steps and their sequence for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equal functions and step sequences. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present invention described herein can be practiced in an order other than that illustrated or described herein.

[0031] In the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is merely a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention, and the embodiments of the present application and the features in the embodiments can be combined with each other unless there is a conflict.

[0032] Please refer to Figures 1-4 , which is used to solve the problem that when collecting the total voltage of multiple batteries, the impedance of each total voltage collection circuit and the impedance of the external circuit form a voltage divider circuit, causing abnormal battery total voltage collection and thus incorrect judgment of the battery status and relay status.

[0033] For details, please refer to Figure 1This is a circuit diagram of a negative electrode isolation circuit provided by an embodiment of the present invention. The embodiment of the present invention provides a negative electrode isolation circuit, including a high-voltage acquisition chip, a sampling current-limiting resistor R2, a high-voltage diode D1, a first negative electrode voltage-dividing sampling resistor R3, a total negative relay and a protection resistor connected in series in sequence. The high-voltage acquisition chip is connected in series with the sampling current-limiting resistor R2 and then in parallel with the second negative electrode voltage-dividing sampling resistor R1. The first end of the high-voltage acquisition chip is connected to the voltage end, the second end of the high-voltage acquisition chip is grounded, and the total negative relay is connected to the negative electrode BAT- of the battery pack. By setting the high-voltage acquisition chip, the sampling current-limiting resistor R2, the high-voltage diode D1, the first negative voltage-dividing sampling resistor R3, the total negative relay and the protection resistor, the high-voltage acquisition chip is connected in series with the sampling current-limiting resistor R2 and then in parallel with the second negative voltage-dividing sampling resistor R1, the first end of the high-voltage acquisition chip is connected to the voltage end, the second end of the high-voltage acquisition chip is grounded, and the total negative relay is connected to the negative electrode BAT- of the battery pack, so as to detect the working state of the total negative relay. When the total negative relay is disconnected, the voltage collected by the high-voltage acquisition chip is the voltage end input voltage. When the total negative relay is connected, the voltage collected by the high-voltage acquisition chip is the voltage after the first negative voltage-dividing sampling resistor R3 and the second negative voltage-dividing sampling resistor R1 jointly divide the voltage. When the voltage end input When the voltage is 5V, when the total negative relay is connected, the voltage collected by the high-voltage acquisition chip is 5V*(R3 / (R1+R3)), which realizes the on-off judgment of the total negative relay by collecting the voltage through the high-voltage acquisition chip, without referring to the positive voltage BAT+ of the battery pack, avoiding the connection of the circuit where the resistor R8 is located, isolating the negative electrode total voltage collection from other total voltage collection circuits, avoiding the formation of a voltage divider circuit between multiple total voltage collection circuits and the external circuit, and cutting off the formation of the equivalent impedance Rx of the external circuit. The high-voltage acquisition chip is set to judge the state of the total negative relay and cut off the external impedance circuit, ensuring that other total voltage collection circuits cannot form a complete voltage divider circuit with the external impedance circuit, thereby avoiding some erroneous fault judgments, improving the collection accuracy of the battery total voltage, thereby improving the reliability of the battery system and reducing costs.

[0034] As a further improvement of the present invention, the resistance value of the first negative voltage-dividing sampling resistor R3 is equal to the resistance value of the second negative voltage-dividing sampling resistor R1. By setting the resistance value of the first negative voltage-dividing sampling resistor R3 and the resistance value of the second negative voltage-dividing sampling resistor R1 to be equal, since the resistance values ​​of the two resistors are equal, according to the series resistor voltage-dividing principle, they accurately divide the voltage between the high-voltage acquisition chip and the sampling current-limiting resistor into two equal parts, so that the high-voltage acquisition chip can more accurately acquire signals related to the input voltage, because the collected voltage is a stable value after precise voltage division, reducing the voltage collection error that may be caused by uneven voltage division, and improving the accuracy and reliability of voltage collection. When judging the working state of the total negative relay by the voltage collected by the high-voltage acquisition chip, when the voltage collected by the high-voltage acquisition chip is the voltage end input voltage, the total negative relay is disconnected, and when the voltage collected by the high-voltage acquisition chip is half of the voltage end input voltage, the total negative relay is connected, which simplifies the judgment of the working state of the total negative relay.

[0035] See Figure 2-Figure 3 The present invention also provides a battery total voltage acquisition circuit, comprising the aforementioned negative electrode isolation circuit and a positive electrode sampling circuit. The positive electrode sampling circuit is connected to the positive electrode BAT+ of the battery pack and comprises a first positive electrode sampling circuit, a second positive electrode sampling circuit, and a third positive electrode sampling circuit connected in parallel. A first resistor R4 is connected in series between the positive electrode BAT+ and the negative electrode BAT- of the battery pack. The negative electrode isolation circuit isolates the negative electrode total voltage acquisition from the positive electrode sampling circuit, preventing the first, second, and third positive electrode sampling circuits from forming a voltage divider circuit with external circuits. The first resistor R4 is connected in series between the positive electrode BAT+ and the negative electrode BAT- of the battery pack. The provision of the first resistor R4 facilitates acquisition of the voltages at both ends of the battery pack, namely, the positive electrode BAT+ and the negative electrode BAT-, to obtain the original voltage of the battery pack.

[0036] Furthermore, the first positive sampling circuit includes a first positive sampling resistor R5 and a total positive relay, the first positive sampling resistor R5 and the total positive relay are connected in series, the first positive sampling resistor R5 is connected to the negative electrode BAT- of the battery pack, and the total positive relay is connected to the positive electrode BAT+ of the battery pack. The first positive sampling circuit includes a first positive sampling resistor R5 and a total positive relay. The first positive sampling resistor and the total positive relay are connected in series. The first positive sampling resistor R5 is connected to the negative electrode BAT- of the battery pack, and the total positive relay is connected to the positive electrode BAT+ of the battery pack. Thus, the first positive sampling resistor R5, the total positive relay, and the battery pack form a complete loop, thereby collecting the voltage of the battery pack passing through the total positive relay and determining the state of the total positive relay. A first positive sampling point is provided between the first positive sampling resistor R5 and the total positive relay. The voltage of the battery pack passing through the total positive relay is obtained by collecting the voltage of the first positive sampling point and referencing the voltage of the negative electrode BAT- of the battery pack. Since the negative electrode isolation circuit isolates the negative electrode BAT- of the battery pack, the first positive sampling circuit and the negative electrode isolation circuit are prevented from forming a complete loop, which would affect the determination of the state of the total positive relay. This prevents the risk of electric shock at external interfaces that may be touched by humans. Isolating the negative electrode of the battery pack by the negative electrode isolation circuit reduces the possibility of accidental current loop formation and improves the safety of the entire battery total voltage collection loop.

[0037] Furthermore, the second positive sampling circuit includes a second positive sampling resistor R6 and a charging relay, the second positive sampling resistor R6 and the charging relay are connected in series, the second positive sampling resistor R6 is connected to the negative electrode BAT- of the battery pack, and the charging relay is connected to the positive electrode BAT+ of the battery pack. The second positive sampling circuit includes a second positive sampling resistor R6 and a charging relay. The second positive sampling resistor R6 and the charging relay are connected in series. The second positive sampling resistor R6 is connected to the negative electrode BAT- of the battery pack, and the charging relay is connected to the positive electrode BAT+ of the battery pack. This complete loop is formed by the second positive sampling resistor R6, the charging relay, and the battery pack. This loop design and voltage acquisition method enable the voltage of the battery pack passing through the charging relay to be acquired and the status of the charging relay to be determined. This allows the voltage of the battery pack passing through the charging relay to be accurately acquired, thereby accurately determining the operating status of the charging relay. A second positive sampling point is provided between the second positive sampling resistor R6 and the charging relay. The voltage of the battery pack passing through the charging relay is obtained by acquiring the voltage at the second positive sampling point and referencing the voltage at the negative electrode BAT- of the battery pack. Because the negative electrode isolation circuit isolates the negative electrode BAT- of the battery pack, this prevents the second positive sampling circuit and the negative electrode isolation circuit from forming a complete loop that would affect the status determination of the charging relay, thereby improving the reliability of the performance determination of the charging relay.

[0038] Furthermore, the third positive sampling circuit includes a third positive sampling resistor R7 and a heating relay, the third positive sampling resistor R7 and the heating relay are connected in series, the third positive sampling resistor R7 is connected to the negative electrode BAT- of the battery pack, and the heating relay is connected to the positive electrode BAT+ of the battery pack. By setting the third positive sampling circuit to include a third positive sampling resistor R7 and a heating relay, the third positive sampling resistor R7 and the heating relay are connected in series, the third positive sampling resistor R7 is connected to the negative electrode BAT- of the battery pack, and the heating relay is connected to the positive electrode BAT+ of the battery pack, the third positive sampling resistor R7, the heating relay and the battery pack form a complete loop, and the voltage of the battery pack passing through the heating relay is collected to determine the state of the heating relay. A third positive sampling point is set between the third positive sampling resistor R7 and the heating relay, and the voltage of the battery pack passing through the heating relay is obtained by collecting the voltage of the third positive sampling point and referring to the voltage of the negative electrode BAT- of the battery pack. Since the negative electrode isolation circuit isolates the negative electrode BAT- terminal of the battery pack, the third positive electrode sampling circuit and the negative electrode isolation circuit are prevented from forming a complete loop, which affects the status judgment of the heating relay. The negative electrode isolation circuit isolates the negative electrode BAT- terminal of the battery pack, so that the third positive electrode sampling circuit cannot form a complete loop with the negative electrode isolation circuit, ensuring that the collected voltage at the third positive electrode sampling point can accurately reflect the status of the heating relay, avoiding the formation of an external loop that interferes with voltage collection, thereby ensuring the accuracy of the collected data, ensuring the normal operation of the battery pack heating function, ensuring that the fault of the heating relay can be discovered in time, and taking prompt measures to repair it when it is not conducting normally or sticking, so as to avoid affecting the performance and service life of the battery due to abnormal heating function.

[0039] Furthermore, a pre-charge relay and a pre-charge resistor are connected in parallel at both ends of the main positive relay. The pre-charge relay and the pre-charge resistor are connected in series. A branch circuit formed by the pre-charge relay and the pre-charge resistor in series is connected in parallel at both ends of the main positive relay. Under normal operating conditions, the main positive relay is responsible for controlling the main connection between the positive electrode of the battery pack and the circuit, while the pre-charge relay and the pre-charge resistor branch exist to perform pre-charging operations on the circuit under specific circumstances.

[0040] See Figure 4 The present invention also provides a method for collecting total battery voltage, which is implemented based on the above-mentioned total battery voltage collection circuit. The method includes the following steps:

[0041] Determining the working state of the total negative relay according to the voltage collected by the high-voltage collection chip;

[0042] collecting a voltage across the first resistor as a first voltage;

[0043] collecting a voltage at one end of the first positive sampling resistor connected to the total positive relay as a second voltage, and determining whether the second voltage is equal to the first voltage; if so, the total positive relay or the pre-filling relay is adhered; otherwise, the total positive relay or the pre-filling relay is normal;

[0044] It should be noted that the judgment of whether the second voltage is equal to the first voltage, if they are equal, then the total positive relay or the pre-filling relay is adhered, otherwise the total positive relay or the pre-filling relay is normal is based on the judgment method when the total positive relay or the pre-filling relay is not closed. When the total positive relay or the pre-filling relay is closed, if the second voltage is equal to the first voltage, then the total positive relay or the pre-filling relay is normal, otherwise the total positive relay or the pre-filling relay cannot be closed. In actual application, there will be a certain voltage loss in the circuit. Therefore, if the collected second voltage is ≥90% of the first voltage, it is considered that the second voltage is equal to the first voltage.

[0045] collecting a voltage at one end of the second positive sampling resistor connected to the charging relay as a third voltage, and determining whether the third voltage is equal to the first voltage; if so, the charging relay is stuck; otherwise, the charging relay is normal;

[0046] It should be noted that determining whether the third voltage is equal to the first voltage, and if so, the charging relay is engaged; otherwise, the charging relay is normal, is based on a judgment method when the charging relay is not closed. When the charging relay is not closed, if the third voltage is equal to the first voltage, the charging relay is normal; otherwise, the charging relay cannot close. In actual applications, there will be certain voltage losses in the circuit. Therefore, if the collected third voltage is ≥ 90% of the first voltage, the third voltage is considered equal to the first voltage.

[0047] collecting a voltage at one end of the third positive sampling resistor connected to the heating relay as a fourth voltage, and determining whether the fourth voltage is equal to the first voltage; if so, the heating relay is stuck; otherwise, the heating relay is normal;

[0048] It should be noted that determining whether the fourth voltage is equal to the first voltage, and if so, the heating relay is engaged; otherwise, the heating relay is normal, is based on a determination method when the heating relay is not closed. When the heating relay is not closed, if the fourth voltage is equal to the first voltage, the heating relay is normal; otherwise, the heating relay cannot close. In actual applications, circuits may have certain voltage losses. Therefore, if the collected fourth voltage is ≥ 90% of the first voltage, the fourth voltage is considered equal to the first voltage.

[0049] Specifically, the second voltage is the voltage at the first sampling point, the third voltage is the voltage at the second sampling point, and the fourth voltage is the voltage at the third sampling point.

[0050] As a further improvement of the present invention, judging the working state of the total negative relay according to the voltage collected by the high-voltage collection chip specifically includes:

[0051] The working state of the total negative relay is determined based on whether the voltage collected by the high-voltage collection chip is the voltage terminal input voltage or half of the voltage terminal input voltage;

[0052] If the voltage is input to the voltage terminal, the total negative relay is normal. If it is half of the voltage input voltage, the total negative relay is stuck.

[0053] It should be noted that if the voltage is input to the voltage end, the total negative relay is normal; if it is half of the voltage input voltage, the total negative relay is stuck. This is a judgment method based on when the total negative relay is not closed. When the total negative relay is closed, if the voltage is input to the voltage end, the total negative relay cannot be closed; if it is half of the voltage input voltage, the total negative relay is normal.

[0054] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0055] The above embodiments merely represent preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the claims. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A negative electrode isolation circuit, characterized in that: It includes a high-voltage acquisition chip, a sampling current-limiting resistor, a high-voltage diode, a first negative-electrode voltage-dividing sampling resistor, a total negative relay, and a protection resistor connected in series. The high-voltage acquisition chip is connected in series with both ends of the sampling current-limiting resistor and then connected in parallel with the second negative-electrode voltage-dividing sampling resistor. The first end of the high-voltage acquisition chip is connected to the voltage end, the second end of the high-voltage acquisition chip is grounded, and the total negative relay is connected to the negative electrode of the battery pack. The resistance value of the first negative voltage-dividing sampling resistor is equal to the resistance value of the second negative voltage-dividing sampling resistor.

2. The negative electrode isolation circuit according to claim 1, characterized in that: The voltage input voltage of the voltage terminal is 5V.

3. A battery total voltage acquisition circuit, characterized in that: The device comprises a negative electrode isolation circuit and a positive electrode sampling circuit according to any one of claims 1 to 2, wherein the positive electrode sampling circuit is connected to the positive electrode of the battery pack, the positive electrode sampling circuit comprises a first positive electrode sampling circuit, a second positive electrode sampling circuit, and a third positive electrode sampling circuit connected in parallel, and a first resistor is connected in series between the positive electrode of the battery pack and the negative electrode of the battery pack.

4. The battery total voltage acquisition circuit according to claim 3, characterized in that: The first positive sampling circuit includes a first positive sampling resistor and a total positive relay, the first positive sampling resistor and the total positive relay are connected in series, the first positive sampling resistor is connected to the negative electrode of the battery pack, and the total positive relay is connected to the positive electrode of the battery pack.

5. The battery total voltage acquisition circuit according to claim 4, characterized in that: The second positive sampling circuit includes a second positive sampling resistor and a charging relay, the second positive sampling resistor and the charging relay are connected in series, the second positive sampling resistor is connected to the negative electrode of the battery pack, and the charging relay is connected to the positive electrode of the battery pack.

6. The battery total voltage acquisition circuit according to claim 5, characterized in that: The third positive electrode sampling circuit includes a third positive electrode sampling resistor and a heating relay, the third positive electrode sampling resistor and the heating relay are connected in series, the third positive electrode sampling resistor is connected to the negative electrode of the battery pack, and the heating relay is connected to the positive electrode of the battery pack.

7. The battery total voltage acquisition circuit according to claim 6, characterized in that: A pre-charging relay and a pre-charging resistor are connected in parallel at both ends of the total positive relay, and the pre-charging relay and the pre-charging resistor are connected in series.

8. A battery total voltage acquisition method, implemented based on the battery total voltage acquisition circuit according to claim 7, characterized in that: The method comprises the following steps: Determining the working state of the total negative relay according to the voltage collected by the high-voltage collection chip; collecting a voltage across the first resistor as a first voltage; collecting a voltage at one end of the first positive sampling resistor connected to the total positive relay as a second voltage, and determining whether the second voltage is equal to the first voltage; if so, the total positive relay or the pre-filling relay is adhered; otherwise, the total positive relay or the pre-filling relay is normal; collecting a voltage at one end of the second positive sampling resistor connected to the charging relay as a third voltage, and determining whether the third voltage is equal to the first voltage; if so, the charging relay is stuck; otherwise, the charging relay is normal; The voltage of one end of the third positive sampling resistor connected to the heating relay is collected as a fourth voltage, and it is determined whether the fourth voltage is equal to the first voltage. If they are equal, the heating relay is stuck; otherwise, the heating relay is normal.

9. The battery total voltage collection method according to claim 8, characterized in that: The determining the working state of the total negative relay according to the voltage collected by the high-voltage collection chip specifically includes: The working state of the total negative relay is determined based on whether the voltage collected by the high-voltage collection chip is the voltage terminal input voltage or half of the voltage terminal input voltage; If the voltage is input to the voltage terminal, the total negative relay is normal. If it is half of the voltage input to the voltage terminal, the total negative relay is stuck.

Images