Cathode isolation circuit, battery total voltage acquisition circuit and acquisition method

Abstract

The invention discloses a cathode isolation circuit, a battery total voltage acquisition circuit and an acquisition method, and the cathode isolation circuit comprises a high-voltage acquisition chip, a sampling current-limiting resistor, a high-voltage diode, a first cathode voltage-dividing sampling resistor, a total negative relay and a protection resistor which are sequentially connected in series, the high-voltage acquisition chip is connected in series with two ends of the sampling current-limiting resistor and then is connected in parallel with the second cathode voltage-dividing sampling resistor, a first end of the high-voltage acquisition chip is connected with a voltage end, a second end of the high-voltage acquisition chip is grounded, and the total negative relay is connected with a cathode of the battery pack. The state of the total negative relay is judged by arranging the high-voltage acquisition chip, the external impedance loop is cut off, and it is ensured that other total voltage acquisition loops of the battery pack cannot form a complete voltage division loop with an external circuit, so that some wrong fault judgment is avoided, the acquisition accuracy of the total voltage of the battery is improved, and the service life of the battery pack is prolonged. Therefore, the reliability of the battery system is improved and the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuits, and in particular relates to a negative electrode isolation circuit, a battery total voltage collection circuit and a collection 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. It 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 faulty state and whether the pre-charging function is successful.

[0003] The current method for collecting the total voltage of the battery is mainly to reduce the voltage to the voltage range that the acquisition chip can normally collect through resistor voltage division, so as to achieve the effect of collecting the battery voltage. When there are multiple battery total voltage collections, the impedance of each total voltage collection circuit and the impedance of the external circuit form a voltage division circuit, causing abnormal battery total voltage collection, resulting in incorrect judgment of the battery status and the status of the relay. Summary of the invention

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

[0005] The negative electrode isolation circuit provided by the present invention comprises 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 which are sequentially connected in series. 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 voltage 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 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 collection method, which is implemented based on the above-mentioned battery total voltage collection circuit, and the method comprises the following steps:

[0014] Determine 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 the voltage of one end of the first positive sampling resistor connected to the total positive relay as a second voltage, and judging whether the second voltage is equal to the first voltage, if they are equal, 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 they are equal, the charging relay is stuck; otherwise, the charging relay is normal;

[0018] The voltage of one end of the heating relay connected to the third positive sampling resistor 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 adhered, 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 according to the voltage collected by the high-voltage collection chip being the voltage input voltage at the voltage end or half of the voltage input voltage at the voltage end;

[0021] If the voltage is input to the voltage terminal, the total negative relay is normal. If the voltage is input to half of 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 collection circuit and a collection method. The present invention sets a high-voltage collection chip to collect voltage to judge the on-off of the total negative relay, without referring to the positive voltage of the battery pack, and isolates the negative electrode total voltage collection from other total voltage collection circuits, thereby avoiding the formation of a voltage-dividing circuit by multiple total voltage collection circuits and an external circuit, and cutting off the formation of an equivalent impedance of the external circuit. The high-voltage collection chip is set to judge the state of the total negative relay, and the external impedance circuit is cut off, ensuring that other total voltage collection circuits cannot form a complete voltage-dividing 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. 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only part of the embodiments of the present invention, rather than all of the embodiments. For ordinary technicians in this field, without paying creative work, other drawings obtained based on these drawings all fall 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 is a circuit schematic diagram of a battery total voltage acquisition circuit provided by an embodiment of the present invention;

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

[0027] Figure 4 The present invention provides a flowchart of a method for collecting total battery voltage. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 used to limit the present invention.

[0029] In order to make the description of the disclosed content more detailed and complete, the following is an illustrative description of the implementation mode and specific examples of the present invention; however, this is not the only form of implementing or applying the specific embodiments of the present invention. The implementation mode covers 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", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those 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 three relationships may exist, 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 may be combined with each other without conflict.

[0032] Please refer to Figure 1-Figure 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-dividing circuit, causing abnormal collection of the total voltage of the battery, thereby causing incorrect judgment of the battery status and the status of the relay.

[0033] For details, please refer to Figure 1A circuit diagram of a negative electrode isolation circuit provided in an embodiment of the present invention. An 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 connected 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 connected 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)), so that the on and off of the total negative relay can be judged by the voltage collected by 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 pole total voltage collection from other total voltage collection circuits, avoiding the formation of a voltage-dividing circuit between multiple total voltage collection circuits and external circuits, 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 the external impedance circuit is cut off, ensuring that other total voltage collection circuits cannot form a complete voltage-dividing 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 voltage-dividing principle of series resistors, 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 accurate voltage division, which reduces the voltage collection error that may be caused by uneven voltage division, improves the accuracy and reliability of voltage collection, and 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 also Figure 2-Figure 3 The present invention also provides a battery total voltage collection circuit, including the above-mentioned negative electrode isolation circuit and positive electrode sampling circuit, the positive electrode sampling circuit is connected to the positive electrode BAT+ of the battery pack, the positive electrode sampling circuit includes 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 R4 is connected in series between the positive electrode BAT+ of the battery pack and the negative electrode BAT- of the battery pack. By setting the negative electrode isolation circuit, the negative electrode total voltage collection is isolated from the positive electrode sampling circuit, so that the first positive electrode sampling circuit, the second positive electrode sampling circuit and the third positive electrode sampling circuit are prevented from forming a voltage dividing loop with the external circuit, and the first resistor R4 is connected in series between the positive electrode BAT+ of the battery pack and the negative electrode BAT- of the battery pack. By setting the first resistor R4, it is convenient to collect the voltages of the two ends of the battery pack, i.e., the positive electrode BAT+ of the battery pack and the negative electrode BAT- of the battery pack 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. By setting the first positive sampling circuit to include 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, so that the first positive sampling resistor R5, the total positive relay and the battery pack form a complete loop, and the voltage of the battery pack passing through the total positive relay is collected, and the state of the total positive relay is judged. A first positive sampling point is set between the first positive sampling resistor R5 and the total positive relay, and 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 referring to 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, it is avoided that the first positive sampling circuit and the negative electrode isolation circuit form a complete loop, which affects the state judgment of the total positive relay, and prevents the risk of electric shock at some external interfaces that people may touch. The negative electrode of the battery pack is isolated by the negative electrode isolation circuit, which reduces the possibility of accidental formation of a current loop 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. The charging relay is connected to the positive electrode BAT+ of the battery pack. The second positive sampling resistor R6, the charging relay and the battery pack form a complete loop. Through this loop design and voltage acquisition method, the voltage of the battery pack passing through the charging relay is acquired to judge the state of the charging relay. The voltage of the battery pack passing through the charging relay can be accurately acquired, and the working state of the charging relay can be accurately judged. A second positive sampling point is set between the second positive sampling resistor R6 and the charging relay. By acquiring the voltage of the second positive sampling point and referring to the voltage of the negative electrode BAT- of the battery pack, the voltage of the battery pack passing through the charging relay is obtained. Since the negative electrode isolation circuit isolates the negative electrode BAT- of the battery pack, the second positive sampling circuit and the negative electrode isolation circuit are prevented from forming a complete loop, which affects the state judgment of the charging relay and improves the reliability of the performance judgment 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, the voltage of the battery pack passing through the heating relay is collected, the state of the heating relay is judged, and 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-end of the battery pack, the third positive electrode sampling circuit is prevented from forming a complete loop with the negative electrode isolation circuit, which affects the state judgment of the heating relay. The negative electrode isolation circuit isolates the negative electrode BAT-end 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 state of the heating relay, avoiding the formation of an external loop to interfere 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 measures to repair it quickly when it is not normally conducted or sticking, so as to avoid affecting the performance and service life of the battery due to abnormal heating function.

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

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

[0041] Determine 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 the voltage of one end of the first positive sampling resistor connected to the total positive relay as a second voltage, and judging whether the second voltage is equal to the first voltage, if they are equal, 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, 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, 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, the collected second voltage ≥ 90% of the first voltage is regarded as the second voltage being 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 they are equal, the charging relay is stuck; otherwise, the charging relay is normal;

[0046] It should be noted that the judgment of whether the third voltage is equal to the first voltage, if the third voltage is equal to the first voltage, the charging relay is adhered, otherwise the charging relay is normal is based on the 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 be closed. In actual application, there will be a certain voltage loss in the circuit. Therefore, the collected third voltage ≥ 90% of the first voltage is regarded as the third voltage being equal to the first voltage.

[0047] collecting a voltage of one end of the third positive sampling resistor connected to the heating relay as a fourth voltage, and judging whether the fourth voltage is equal to the first voltage; if they are equal, the heating relay is adhered; otherwise, the heating relay is normal;

[0048] It should be noted that the judgment of whether the fourth voltage is equal to the first voltage, if the fourth voltage is equal to the first voltage, the heating relay is stuck, otherwise the heating relay is normal is based on the judgment 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 be closed. In actual application, there will be a certain voltage loss in the circuit. Therefore, the collected fourth voltage ≥ 90% of the first voltage is regarded as the fourth voltage being 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 according to the voltage collected by the high-voltage collection chip being the voltage input voltage at the voltage end or half of the voltage input voltage at the voltage end;

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

[0054] The technical features of the above embodiments may 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 only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached 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 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 both ends of the sampling current-limiting resistor and then connected in parallel with the second negative 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.

2. The negative electrode isolation circuit according to claim 1, characterized in that: 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.

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

4. A battery total voltage acquisition circuit, characterized in that: It includes the negative electrode isolation circuit and the positive electrode sampling circuit as described in any one of claims 1 to 3, the positive electrode sampling circuit is connected to the positive electrode of the battery pack, the positive electrode sampling circuit includes 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.

5. The battery total voltage acquisition circuit according to claim 4, 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.

6. 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.

7. 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.

8. The battery total voltage acquisition circuit according to claim 5, 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.

9. A battery total voltage collection method, implemented based on the battery total voltage collection circuit according to any one of claims 4 to 8, characterized in that: The method comprises the following steps: Determine 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 the voltage of one end of the first positive sampling resistor connected to the total positive relay as a second voltage, and judging whether the second voltage is equal to the first voltage, if they are equal, 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 they are equal, the charging relay is stuck; otherwise, the charging relay is normal; The voltage of one end of the heating relay connected to the third positive sampling resistor 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 adhered, otherwise the heating relay is normal.

10. The battery total pressure collection method according to claim 9, characterized in that: The step of judging 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 according to the voltage collected by the high-voltage collection chip being the voltage input voltage at the voltage end or half of the voltage input voltage at the voltage end; If the voltage is input to the voltage terminal, the total negative relay is normal. If the voltage is input to half of the voltage terminal, the total negative relay is stuck.

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