Detection circuit for energy storage battery and energy storage equipment

Abstract

The invention provides a detection circuit for an energy storage battery and energy storage equipment. The detection circuit for the energy storage battery comprises a first resistor; the first end of the second resistor is connected with the second end of the first resistor, and the second end of the second resistor is connected with the reference ground; the voltage division circuit is located between the second end of the second resistor and the negative electrode of the energy storage battery; the first end of the first switch is connected with the positive electrode of the energy storage battery, and the second end of the first switch is connected with the first end of the first resistor; the first end of the second switch is connected with the second end of the first resistor; the third resistor is located between the second end of the second switch and the negative electrode of the energy storage battery; and the micro-control unit is connected with the output end of the voltage division circuit and is used for determining a first insulation resistance value of the energy storage battery according to voltage values output by the output end of the voltage division circuit when the first switch and the second switch are in different conduction states. In the process, the detection precision of the insulation resistance value of the energy storage battery is improved.

Description

Technical Field

[0001] The present invention relates to the field of detection technology, and in particular to a detection circuit and energy storage device for an energy storage battery. Background Art

[0002] Insulation testing is to detect the insulation resistance between the positive and negative poles of the energy storage battery and the casing. Current energy storage battery products need to add insulation testing functions to diagnose whether the energy storage battery has leakage risks.

[0003] In the related art, insulation detection is divided into two methods: a balanced bridge method and an unbalanced bridge method. Figure 1 The detection circuit using the balanced bridge method is shown in FIG. Figure 1 As shown, the detection circuit includes a first resistor R1', a second resistor R2', a third resistor R3', a fourth resistor R4', a first switch S1', a second switch S2', a first virtual resistor R + and the second virtual resistor R - , wherein the energy storage battery outputs power through the positive output terminal PACK+, the first end of the first resistor R1' is connected to the positive electrode BAT+ of the energy storage battery, the second end of the fourth resistor R4' is connected to the negative electrode BAT- of the energy storage battery, the second end of the second resistor R2' is connected to the reference ground PE', and the insulation resistance R between the positive electrode of the energy storage battery and the reference ground is estimated by using the output signal of the first end of the fourth resistor R4' + And the insulation resistance R between the negative electrode of the energy storage battery and the reference ground - .

[0004] Figure 2 The detection circuit using the unbalanced bridge method is shown in FIG. Figure 2 As shown, the detection circuit includes a first resistor R1', a second resistor R2', a third resistor R3', a fourth resistor R4', a fifth resistor R5', a first switch S1', a second switch S2', a first virtual resistor R + and the second virtual resistor R - The first end of the first resistor R1' is connected to the positive electrode of the energy storage battery, the second end of the fourth resistor R4' is connected to the negative electrode BAT- of the energy storage battery, the second end of the second resistor R2' is connected to the reference ground PE', and the first end of the fourth resistor R4' outputs a signal to estimate the insulation resistance R between the positive electrode BAT+ of the energy storage battery and the reference ground PE'. + And the insulation resistance R between the negative electrode BAT- of the energy storage battery and the reference ground PE' - .

[0005] Although the balanced bridge method has a fast detection speed and high efficiency, it is generally costly and cannot detect defects with instantaneous changes. The existing detection circuit using the unbalanced bridge method cannot accurately estimate the insulation resistance of the energy storage battery. Summary of the invention

[0006] The present invention aims to at least solve the technical problems existing in the prior art or related art that, although the balanced bridge method has a fast detection speed and high efficiency, it is generally costly and cannot detect defects with instantaneous changes, while the existing detection circuit using the unbalanced bridge method cannot accurately estimate the insulation resistance of the energy storage battery.

[0007] To this end, a first aspect of the present invention is to provide a detection circuit for an energy storage battery.

[0008] A second aspect of the present invention provides an energy storage device.

[0009] In view of this, according to a first aspect of the present invention, the present invention provides a detection circuit for an energy storage battery, comprising: a first resistor; a second resistor, wherein a first end of the second resistor is connected to a second end of the first resistor, and a second end of the second resistor is connected to a reference ground; a voltage divider circuit, wherein a first end of the voltage divider circuit is connected to a second end of the second resistor, and a second end of the voltage divider circuit is connected to a negative electrode of the energy storage battery; a first switch, wherein a first end of the first switch is connected to a positive electrode of the energy storage battery, and a second end of the first switch is connected to a first end of the first resistor; a second switch, wherein a first end of the second switch is connected to a second end of the first resistor; a third resistor, wherein a first end of the third resistor is connected to a second end of the second switch, and a second end of the third resistor is connected to a negative electrode of the energy storage battery; and a microcontroller unit connected to an output end of the voltage divider circuit, and used to determine a first insulation resistance value of the energy storage battery according to a voltage value outputted by the output end of the voltage divider circuit when the first switch and the second switch are in different conduction states.

[0010] The technical solution of the present invention proposes a detection circuit for an energy storage battery, the detection circuit includes a first resistor, a second resistor, a third resistor, a voltage divider circuit, a first switch, a second switch and a micro control unit. After the first resistor, the second resistor and the voltage divider circuit are connected, the first switch is used to connect to the positive electrode of the energy storage battery, and at the same time, the second end of the first resistor is connected to the negative electrode of the energy storage battery through the third resistor and the second switch. Since the second end of the second resistor is connected to the reference ground, when the first switch and the second switch are in different conduction states, the resistor connected between the positive electrode of the energy storage battery and the reference ground, and the resistor connected between the negative electrode of the energy storage battery and the reference ground are different. Therefore, the voltage value output by the output end of the voltage divider circuit when the first switch and the second switch are in different conduction states can be detected to obtain the insulation resistance of the energy storage battery compared to the reference ground, that is, the first insulation resistance determined by the present application.

[0011] In the above technical solution, when the first switch and the second switch are in different conduction states, more resistors can be connected between the positive electrode of the energy storage battery and the reference ground, and more resistors can be connected between the negative electrode of the energy storage battery and the reference ground, so that the calculated first insulation resistance value is more accurate. Therefore, when the detection circuit for the energy storage battery proposed in the present invention measures the insulation resistance value of the energy storage battery, the accuracy of the measured insulation resistance value can be improved.

[0012] In addition, the detection circuit for the energy storage battery proposed by the present invention also has the following additional technical features.

[0013] In some technical solutions, optionally, the micro control unit is specifically used to: obtain a first voltage value output by the output end of the voltage divider circuit in a first state, in which the first switch is in an on state and the second switch is in an off state; obtain a second voltage value output by the output end of the voltage divider circuit in a second state, in which the first switch is in an off state and the second switch is in an on state; determine a first insulation resistance of the energy storage battery based on the first voltage value and the second voltage value.

[0014] In this technical solution, in the first state, the first switch is in the on state, and the second switch is in the off state. At this time, the first resistor, the second resistor, and the resistor on the voltage divider circuit can be connected to the positive electrode of the energy storage battery and the negative electrode of the energy storage battery. At this time, a first virtual resistor between the positive electrode of the energy storage battery and the reference ground and a second virtual resistor between the negative electrode of the energy storage battery and the reference ground are fictitious, wherein the resistance values ​​of the first virtual resistor and the second virtual resistor are also the first insulation resistance values ​​required to be measured in this application.

[0015] Among them, after the first resistor and the second resistor are connected in series, they will be connected in parallel with the first virtual resistor and serve as the upper bridge arm, and the voltage divider circuit is connected in parallel with the second virtual resistor as the lower bridge arm. At this time, the current of the upper bridge arm and the lower bridge arm are equal. The voltage value output by the output end of the voltage divider circuit can be used to reversely calculate the voltage value at the second end of the second resistor in the first state, and based on the voltage value at the second end of the second resistor, the first formula between the first virtual resistor and the second virtual resistor is constructed.

[0016] Similarly, in the second state, the first switch is in the off state and the second switch is in the on state. At this time, the second resistor and the third resistor are connected in series and in parallel with the voltage divider circuit, and at the same time, they are also connected in parallel with the second virtual resistor. The first virtual resistor serves as the upper bridge arm, and the second resistor, the third resistor, the voltage divider circuit and the second virtual resistor serve as the lower bridge arm. At this time, the currents of the upper bridge arm and the lower bridge arm are equal, and the voltage value at the second end of the second resistor in the second state can be reversely calculated based on the voltage value output by the output end of the voltage divider circuit, and a second formula between the first virtual resistor and the second virtual resistor is constructed based on the voltage value at the second end of the second resistor.

[0017] A set of linear equations of two variables can be constructed according to the first formula and the second formula, and the resistance values ​​of the first virtual resistor and the second virtual resistor can be obtained by solving the set of linear equations of two variables, thereby obtaining the first insulation resistance of the energy storage battery.

[0018] In some technical solutions, optionally, the micro control unit is also used to: output first abnormality information based on the first insulation resistance being less than a first threshold value; output no abnormality information based on the first insulation resistance being greater than or equal to the first threshold value; wherein the first abnormality information is used to indicate that the insulation resistance of the energy storage battery is abnormal, and the no abnormality information is used to indicate that the insulation resistance of the energy storage battery is normal.

[0019] In this technical solution, in order to meet safety requirements, the insulation resistance of the energy storage battery needs to be greater than the first threshold, that is, the first insulation resistance is greater than the first threshold.

[0020] In the technical solution of the present invention, when the first insulation resistance is less than the first threshold, it is considered that the insulation resistance of the energy storage battery does not meet the safety requirements, and the first abnormal information is output to remind the user that the insulation resistance of the energy storage battery is abnormal and maintenance is required.

[0021] During this process, the user can perform timely maintenance on the energy storage battery according to the first abnormal information so as to improve the safety of using the energy storage battery.

[0022] In the above technical solution, when the first insulation resistance is greater than or equal to the first threshold, it is considered that the insulation resistance of the energy storage battery meets the safety requirements, and the insulation resistance of the energy storage battery is notified to the user by outputting no abnormality information. In this process, it is convenient for the user to grasp the status of the energy storage battery in a timely manner.

[0023] In some technical schemes, optionally, the voltage divider circuit includes: a fourth resistor, a first end of the fourth resistor is connected to the second end of the second resistor; a fifth resistor, a first end of the fifth resistor is connected to the second end of the fourth resistor, and the second end of the fifth resistor is connected to the negative electrode of the energy storage battery; wherein the first end of the fifth resistor is the output end of the voltage divider circuit.

[0024] In this technical solution, the fourth resistor and the fifth resistor constitute a voltage divider circuit, wherein the first end of the fifth resistor is the output end of the voltage divider circuit. When the resistance values ​​of the first resistor, the second resistor, and the third resistor and the conduction conditions of the first switch and the second switch are known, the voltage at the first end of the fifth resistor can be used to reversely calculate the voltage at the second end of the second resistor to estimate the insulation resistance.

[0025] In addition, when a larger voltage is input, the microcontroller unit may be damaged. By selecting reasonable resistance values ​​for the fourth resistor and the fifth resistor, the voltage input to the microcontroller unit can be limited, thereby reducing the probability of damage to the microcontroller unit. Obviously, in this process, the reliability of the detection circuit of the user's energy storage battery can be improved.

[0026] In some technical solutions, optionally, the detection circuit for the energy storage battery also includes: a processing chip, a first end of the processing chip is connected to the first end of the fifth resistor, a second end of the processing chip is connected to the second end of the fifth resistor, and an output end of the processing chip is connected to a micro control unit; the micro control unit is also used to: obtain a first differential voltage output by the processing chip in a first state and a second differential voltage output by the processing chip in a second state; determine a second insulation resistance value of the energy storage battery based on the first differential voltage and the second differential voltage.

[0027] In this technical solution, a processing chip is set up to connect the first end of the fifth resistor, the second end of the fifth resistor and the micro control unit, and in the first state, the processing chip outputs a first differential voltage, and in the second state, the processing chip outputs a second differential voltage. At this time, the micro control unit can calculate the second insulation resistance of the energy storage battery based on the first differential voltage and the second differential voltage.

[0028] In this process, two methods can be used to synchronously measure the insulation resistance of the energy storage battery, and then obtain the first insulation resistance and the second insulation resistance. At this time, the insulation resistances measured by the two methods can be used as backup for each other, and when the port connection between the microcontroller unit and the output end of the voltage divider circuit is abnormal, the processing chip is used to measure the insulation resistance of the energy storage battery.

[0029] Obviously, the detection circuit for the energy storage battery proposed in the present invention can still measure the insulation resistance of the energy storage battery when the port connection between the micro control unit and the output end of the voltage divider circuit is abnormal, thereby ensuring accurate measurement of the insulation condition of the energy storage battery.

[0030] In some technical solutions, the first differential voltage can be understood as the voltage difference between the two ends of the fifth resistor in the first state. Similarly, the second differential voltage can be understood as the voltage difference between the two ends of the fifth resistor in the second state.

[0031] In some technical solutions, optionally, the micro control unit is also used to: obtain the insulation resistance difference between the first insulation resistance and the second insulation resistance; determine that the first insulation resistance and the second insulation resistance are valid detection results based on the insulation resistance difference being less than or equal to the second threshold; output first abnormality information based on the first insulation resistance and / or the second insulation resistance being less than the first threshold; output no abnormality information based on the first insulation resistance and / or the second insulation resistance being greater than or equal to the first threshold; wherein the first abnormality information is used to indicate that the insulation resistance of the energy storage battery is abnormal, and the no abnormality information is used to indicate that the insulation resistance of the energy storage battery is normal.

[0032] In this technical solution, the insulation resistance difference between the first insulation resistance and the second insulation resistance is calculated, and the insulation resistance difference is compared with the second threshold value, so as to use the comparison result of the insulation resistance difference with the second threshold value to verify whether the first insulation resistance and the second insulation resistance are valid detection results.

[0033] Specifically, if the insulation resistance difference is less than or equal to the second threshold, the first insulation resistance and the second insulation resistance are determined to be valid detection results.

[0034] When the first insulation resistance and the second insulation resistance are valid detection results, the first insulation resistance and the second insulation resistance are compared with the first threshold value, and corresponding information is output according to the comparison result. In this process, when the insulation resistance of the energy storage battery does not meet the safety requirements, the first abnormal information can be output to remind the user that the insulation resistance of the energy storage battery is abnormal, so as to perform maintenance in time.

[0035] In some technical solutions, optionally, the micro control unit is also used to: determine that the first insulation resistance is an invalid detection result based on the insulation resistance difference being greater than a second threshold; and output second abnormal information when the first insulation resistance is an invalid detection result; wherein the second abnormal information is used to indicate that the first port is abnormal, and the first port is a port where the micro control unit is connected to the output end of the voltage divider circuit.

[0036] In this technical solution, when the insulation resistance difference is greater than the second threshold, the first insulation resistance is considered to be an invalid detection result. At this time, the second abnormal information is output to remind the user to maintain the abnormal first port in time.

[0037] In this process, the influence of the abnormality of the first port on the insulation resistance determination of the energy storage battery can be reduced, so as to ensure the safe use of the energy storage battery.

[0038] In some technical solutions, optionally, the detection circuit for the energy storage battery also includes: a third switch, connected in series between the second end of the second resistor and the reference ground; in the first state and the second state, the third switch is in an on state.

[0039] In this technical solution, the third switch is set to control the third switch to be turned on when the insulation resistance of the energy storage battery is measured, and to control the third switch to be turned off after the insulation resistance of the energy storage battery is measured.

[0040] When the third switch is turned off, the connection between the second resistor, the voltage divider circuit and the reference ground can be cut off to avoid a leakage circuit between the energy storage battery and the reference ground, thereby improving the safety of the energy storage battery.

[0041] In some technical solutions, optionally, the first switch, the second switch and the third switch are optocoupler relays.

[0042] In this technical solution, the optocoupler relay has a voltage isolation effect. Therefore, when the optocoupler relay is used, the reliability of the detection circuit for the energy storage battery can be improved.

[0043] According to a second aspect of the present invention, the present invention provides an energy storage device, comprising: an energy storage battery; and a detection circuit for the energy storage battery as described in any one of the first aspects.

[0044] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0046] Figure 1 One of the topological schematic diagrams of the detection circuit for the energy storage battery in the related art is shown;

[0047] Figure 2 One of the topological schematic diagrams of the detection circuit for the energy storage battery in the related art is shown;

[0048] Figure 3 One of the topological schematic diagrams of the detection circuit for the energy storage battery in the embodiment of the present invention is shown;

[0049] Figure 4 The second topological schematic diagram of the detection circuit for the energy storage battery in the embodiment of the present invention is shown;

[0050] Figure 5 The third topological schematic diagram of the detection circuit for the energy storage battery in the embodiment of the present invention is shown;

[0051] Figure 6 A fourth topological schematic diagram of a detection circuit for an energy storage battery in an embodiment of the present invention is shown;

[0052] Figure 7 One of the flow charts of the control method of the detection circuit for the energy storage battery in the embodiment of the present invention is shown;

[0053] Figure 8 The second flowchart of the control method of the detection circuit for the energy storage battery in the embodiment of the present invention is shown.

[0054] in, Figure 1 and Figure 2 The corresponding relationship between the reference numerals and the component names is as follows:

[0055] R1' first resistor, R2' second resistor, R3' third resistor, R4' fourth resistor, R5' fifth resistor, S1' first switch, S2' second switch, BAT+ positive electrode, BAT- negative electrode, PACK+ positive output terminal, R + The first virtual resistor, R - The second virtual resistor, PE', is referenced to ground.

[0056] in, Figures 3 to 6 The corresponding relationship between the reference numerals and the component names is as follows:

[0057] 100 detection circuit for energy storage battery, R1 first resistor, R2 second resistor, R3 third resistor, R4 fourth resistor, R5 fifth resistor, 102 voltage divider circuit, 104 micro control unit, 106 processing chip, S1 first switch, S2 second switch, S3 third switch, 202 energy storage battery, BAT+ positive electrode, BAT- negative electrode, PACK+ positive output terminal, PE reference ground, R + The first virtual resistor, R - The second virtual resistor is 200 energy storage devices. DETAILED DESCRIPTION

[0058] In order to more clearly understand the above aspects, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0059] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0060] In one embodiment of the present application, Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, a detection circuit 100 for an energy storage battery 202 is provided, comprising: a first resistor R1; a second resistor R2, wherein a first end of the second resistor R2 is connected to a second end of the first resistor R1, and a second end of the second resistor R2 is connected to a reference ground PE; a voltage divider circuit 102, wherein a first end of the voltage divider circuit 102 is connected to a second end of the second resistor R2, and a second end of the voltage divider circuit 102 is connected to a negative electrode BAT- of the energy storage battery 202; a first switch S1, wherein a first end of the first switch S1 is connected to a positive electrode BAT+ of the energy storage battery 202, and a second end of the first switch S1 is connected to a positive electrode BAT+ of the energy storage battery 202. The two ends are connected to the first end of the first resistor R1; the second switch S2, the first end of the second switch S2 is connected to the second end of the first resistor R1; the third resistor R3, the first end of the third resistor R3 is connected to the second end of the second switch S2, and the second end of the third resistor R3 is connected to the negative electrode BAT- of the energy storage battery 202; the micro control unit 104 is connected to the output end of the voltage divider circuit 102, and is used to determine the first insulation resistance of the energy storage battery 202 according to the voltage value output by the output end of the voltage divider circuit 102 when the first switch S1 and the second switch S2 are in different conduction states.

[0061] In some embodiments, optionally, the reference ground PE may be a casing of an energy storage device where the energy storage battery 202 is located.

[0062] The embodiment of the present invention provides a detection circuit 100 for an energy storage battery 202, the detection circuit comprising a first resistor R1, a second resistor R2, a third resistor R3, a voltage divider circuit 102, a first switch S1, a second switch S2 and a micro control unit 104. After the first resistor R1, the second resistor R2 and the voltage divider circuit 102 are connected, the first switch S1 is used to connect to the positive electrode BAT+ of the energy storage battery 202, and at the same time, the second end of the first resistor R1 is connected to the negative electrode BAT- of the energy storage battery 202 through the third resistor R3 and the second switch S2. Since the second end of the second resistor R2 is connected to the reference ground PE, when the first switch S1 and the second switch S2 are in different conduction states, the resistance connected between the positive electrode BAT+ of the energy storage battery 202 and the reference ground PE, and the resistance connected between the negative electrode BAT- of the energy storage battery 202 and the reference ground PE are different. Therefore, the voltage value output by the output end of the voltage divider circuit 102 when the first switch S1 and the second switch S2 are in different conduction states can be detected to obtain the insulation resistance between the energy storage battery 202 and the reference ground PE, that is, the first insulation resistance determined in the present application.

[0063] In the above embodiment, when the first switch S1 and the second switch S2 are in different conduction states, more resistors can be connected between the positive electrode BAT+ of the energy storage battery 202 and the reference ground PE, and more resistors can be connected between the negative electrode BAT- of the energy storage battery 202 and the reference ground PE, so that the calculated first insulation resistance value is more accurate. Therefore, when the detection circuit 100 for the energy storage battery 202 proposed by the present invention measures the insulation resistance value of the energy storage battery 202, the accuracy of the measured insulation resistance value can be improved.

[0064] In some embodiments, optionally, the microcontroller unit 104 is specifically used to: obtain a first voltage value outputted by the output terminal of the voltage divider circuit 102 in a first state, in which the first switch S1 is in an on state and the second switch S2 is in an off state; obtain a second voltage value outputted by the output terminal of the voltage divider circuit 102 in a second state, in which the first switch S1 is in an off state and the second switch S2 is in an on state; determine a first insulation resistance of the energy storage battery 202 based on the first voltage value and the second voltage value.

[0065] In this embodiment, in the first state, the first switch S1 is in the on state, and the second switch S2 is in the off state. At this time, the first resistor R1, the second resistor R2 and the resistor on the voltage divider circuit 102 can be connected to the positive electrode BAT+ of the energy storage battery 202 and the negative electrode BAT- of the energy storage battery 202. At this time, a first virtual resistor R1 is created between the positive electrode BAT+ of the energy storage battery 202 and the reference ground PE. + and a second virtual resistor R between the negative electrode BAT- of the energy storage battery 202 and the reference ground PE - , where the first virtual resistor R + and the second virtual resistor R - The resistance value is the first insulation resistance value that needs to be measured in this application.

[0066] The first resistor R1 and the second resistor R2 are connected in series to form a first virtual resistor R + The voltage divider circuit 102 and the second virtual resistor R - The upper bridge arm and the lower bridge arm are connected in parallel as the lower bridge arm. At this time, the currents of the upper bridge arm and the lower bridge arm are equal. The voltage value outputted by the output end of the voltage divider circuit 102 can be used to reversely infer the voltage value at the second end of the second resistor R2 in the first state, and the voltage value at the second end of the second resistor R2 can be used to construct the first virtual resistor R + and the second virtual resistor R - The first formula between .

[0067] Similarly, in the second state, the first switch S1 is in the off state, and the second switch S2 is in the on state. At this time, the second resistor R2 and the third resistor R3 are connected in series and in parallel with the voltage divider circuit 102, and at the same time, the second virtual resistor R - In parallel, the first virtual resistor R + As the upper bridge arm, the second resistor R2, the third resistor R3, the voltage divider circuit 102 and the second virtual resistor R - At this time, the currents of the upper bridge arm and the lower bridge arm are equal, and the voltage value at the second end of the second resistor R2 in the second state can be reversely calculated according to the voltage value output by the output end of the voltage divider circuit 102, and the voltage value at the second end of the second resistor R2 can be constructed based on the voltage value at the second end of the second resistor R2. + and the second virtual resistor R - The second formula between .

[0068] A set of two-variable linear equations can be constructed based on the first formula and the second formula, and the first virtual resistance R can be obtained by solving the set of two-variable linear equations. + and the second virtual resistor R - The resistance value of the energy storage battery 202 is obtained.

[0069] In some embodiments, optionally, the micro control unit 104 is further used to: output first abnormality information based on the first insulation resistance being less than a first threshold; output no abnormality information based on the first insulation resistance being greater than or equal to the first threshold; wherein the first abnormality information is used to indicate that the insulation resistance of the energy storage battery 202 is abnormal, and the no abnormality information is used to indicate that the insulation resistance of the energy storage battery 202 is normal.

[0070] In this embodiment, in order to meet the safety requirements, the insulation resistance of the energy storage battery 202 needs to be greater than the first threshold, that is, the first insulation resistance is greater than the first threshold.

[0071] In an embodiment of the present invention, when the first insulation resistance is less than the first threshold, it is considered that the insulation resistance of the energy storage battery 202 does not meet the safety requirements, and the first abnormal information is output to remind the user that the insulation resistance of the energy storage battery 202 is abnormal and maintenance is required.

[0072] During this process, the user can perform timely maintenance on the energy storage battery 202 according to the first abnormal information, so as to improve the safety of using the energy storage battery 202 .

[0073] In the above embodiment, when the first insulation resistance is greater than or equal to the first threshold, it is considered that the insulation resistance of the energy storage battery 202 meets the safety requirements, and the insulation resistance of the energy storage battery 202 is notified to the user by outputting the no abnormality information. In this process, it is convenient for the user to grasp the status of the energy storage battery 202 in a timely manner.

[0074] In some embodiments, optionally, the voltage divider circuit 102 includes: a fourth resistor R4, a first end of the fourth resistor R4 is connected to the second end of the second resistor R2; a fifth resistor R5, a first end of the fifth resistor R5 is connected to the second end of the fourth resistor R4, and a second end of the fifth resistor R5 is connected to the negative electrode BAT- of the energy storage battery 202; wherein the first end of the fifth resistor R5 is the output end of the voltage divider circuit 102.

[0075] In this embodiment, the fourth resistor R4 and the fifth resistor R5 constitute a voltage divider circuit 102, wherein the first end of the fifth resistor R5 is the output end of the voltage divider circuit 102. When the resistance values ​​of the first resistor R1, the second resistor R2, and the third resistor R3 and the conduction conditions of the first switch S1 and the second switch S2 are known, the voltage at the first end of the fifth resistor R5 can be used to reversely calculate the voltage at the second end of the second resistor R2 to estimate the insulation resistance.

[0076] In addition, when a larger voltage is input, the microcontroller unit 104 may be damaged. By selecting reasonable resistance values ​​for the fourth resistor R4 and the fifth resistor R5, the magnitude of the voltage input to the microcontroller unit 104 can be limited, thereby reducing the probability of damage to the microcontroller unit 104. Obviously, in this process, the reliability of the detection circuit of the user energy storage battery 202 can be improved.

[0077] In some embodiments, optionally, the detection circuit 100 for the energy storage battery 202 also includes: a processing chip 106, a first end of the processing chip 106 is connected to the first end of the fifth resistor R5, a second end of the processing chip 106 is connected to the second end of the fifth resistor R5, and an output end of the processing chip 106 is connected to the micro control unit 104; the micro control unit 104 is also used to: obtain a first differential voltage output by the processing chip 106 in the first state and a second differential voltage output by the processing chip 106 in the second state; determine a second insulation resistance value of the energy storage battery 202 based on the first differential voltage and the second differential voltage.

[0078] In this embodiment, the processing chip 106 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 and the micro control unit 104, and in the first state, the processing chip 106 outputs a first differential voltage, and in the second state, the processing chip 106 outputs a second differential voltage. At this time, the micro control unit 104 can calculate the second insulation resistance of the energy storage battery 202 according to the first differential voltage and the second differential voltage.

[0079] In this process, two methods can be used to synchronously measure the insulation resistance of the energy storage battery 202, thereby obtaining a first insulation resistance and a second insulation resistance. At this time, the insulation resistances obtained by the two methods can be used as a backup for each other, and when the connection between the microcontroller unit 104 and the output end of the voltage divider circuit 102 is abnormal, the processing chip 106 is used to measure the insulation resistance of the energy storage battery 202.

[0080] Obviously, the detection circuit 100 for the energy storage battery 202 proposed by the present invention can still measure the insulation resistance of the energy storage battery 202 when the connection between the port connecting the micro control unit 104 and the output end of the voltage divider circuit 102 is abnormal, thereby ensuring accurate measurement of the insulation condition of the energy storage battery 202.

[0081] In some embodiments, the processing chip 106 includes an analog-to-digital converter, wherein the analog-to-digital converter acquires an AD value through differential sampling.

[0082] In some embodiments, the first differential voltage may be understood as the voltage difference between the two ends of the fifth resistor R5 in the first state. Similarly, the second differential voltage may be understood as the voltage difference between the two ends of the fifth resistor R5 in the second state.

[0083] In some embodiments, optionally, the micro control unit 104 is further used to: obtain the insulation resistance difference between the first insulation resistance and the second insulation resistance; determine that the first insulation resistance and the second insulation resistance are valid detection results based on the insulation resistance difference being less than or equal to the second threshold; output first abnormality information based on the first insulation resistance and / or the second insulation resistance being less than the first threshold; output no abnormality information based on the first insulation resistance and / or the second insulation resistance being greater than or equal to the first threshold; wherein the first abnormality information is used to indicate that the insulation resistance of the energy storage battery 202 is abnormal, and the no abnormality information is used to indicate that the insulation resistance of the energy storage battery 202 is normal.

[0084] In this embodiment, the insulation resistance difference between the first insulation resistance and the second insulation resistance is calculated, and the insulation resistance difference is compared with the second threshold value, so as to verify whether the first insulation resistance and the second insulation resistance are valid detection results based on the comparison result of the insulation resistance difference and the second threshold value.

[0085] Specifically, if the insulation resistance difference is less than or equal to the second threshold, the first insulation resistance and the second insulation resistance are determined to be valid detection results.

[0086] When the first insulation resistance and the second insulation resistance are valid detection results, the first insulation resistance and the second insulation resistance are compared with the first threshold value, and corresponding information is output according to the comparison result. In this process, when the insulation resistance of the energy storage battery 202 does not meet the safety requirements, the first abnormal information can be output to remind the user that the insulation resistance of the energy storage battery 202 is abnormal, so as to perform maintenance in time.

[0087] In some embodiments, optionally, the micro control unit 104 is also used to: determine that the first insulation resistance is an invalid detection result based on the insulation resistance difference being greater than a second threshold; and output second abnormal information when the first insulation resistance is an invalid detection result; wherein the second abnormal information is used to indicate that the first port is abnormal, and the first port is the port where the micro control unit 104 is connected to the output end of the voltage divider circuit 102.

[0088] In this embodiment, when the insulation resistance difference is greater than the second threshold, the first insulation resistance is considered to be an invalid detection result. At this time, the second abnormal information is output to remind the user to maintain the abnormal first port in time.

[0089] In this process, the influence of the abnormality of the first port on the insulation resistance determination of the energy storage battery 202 can be reduced, so as to ensure the safe use of the energy storage battery 202.

[0090] In some embodiments, optionally, the detection circuit 100 for the energy storage battery 202 further includes: a third switch S3 connected in series between the second end of the second resistor R2 and the reference ground PE; in the first state and the second state, the third switch S3 is in an on state.

[0091] In this embodiment, the third switch S3 is set to control the third switch S3 to be turned on when the insulation resistance of the energy storage battery 202 is measured, and to control the third switch S3 to be turned off after the insulation resistance of the energy storage battery 202 is measured.

[0092] When the third switch S3 is turned off, the connection between the second resistor R2, the voltage divider circuit 102 and the reference ground PE can be cut off to avoid a leakage circuit between the energy storage battery 202 and the reference ground PE, thereby improving the safety of the energy storage battery 202.

[0093] like Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, in the first state, Figure 4 The topology changes to Figure 5 In the second state, Figure 5 The topology changes to Figure 6 Topological diagram of .

[0094] In some embodiments, Figure 7 As shown, the method for detecting the first insulation resistance of the energy storage battery includes:

[0095] Step 702, the micro control unit is initialized. If the judgment result is yes, step 704 is executed. If the judgment result is no, step 702 is executed.

[0096] Step 704: the first switch and the third switch are closed, and the second switch is opened.

[0097] Step 706: The micro control unit detects the AD value for the first time.

[0098] Step 708: the second switch and the third switch are closed, and the first switch is opened.

[0099] Step 710: The micro control unit detects the AD value for the second time.

[0100] Step 712, calculate whether the insulation resistance is abnormal, if the judgment result is yes, execute step 714, if the judgment result is no, execute step 716.

[0101] Step 714, reporting insulation abnormality.

[0102] Step 716, insulation detection ends.

[0103] Step 718, close the relay.

[0104] In some embodiments, Figure 8 As shown, the detection method of the first insulation resistance and the second insulation resistance of the energy storage battery includes:

[0105] Step 802, the micro control unit is initialized. If the judgment result is yes, step 804 is executed. If the judgment result is no, step 802 is executed.

[0106] Step 804: the first switch and the third switch are closed, and the second switch is opened.

[0107] Step 8062, the microcontroller unit detects the first AD value through IIC acquisition.

[0108] Step 8064, the micro control unit detects the first AD value through IO acquisition.

[0109] Step 808: the second switch and the third switch are closed, and the first switch is opened.

[0110] Step 8102, the microcontroller unit detects the second AD value through IIC acquisition.

[0111] Step 8104, through IO acquisition, the micro control unit detects the second AD value.

[0112] Step 812, calculate whether the insulation resistance is abnormal, if the judgment result is yes, execute step 814, if the judgment result is no, execute step 816.

[0113] Step 814, reporting insulation abnormality.

[0114] Step 816, insulation detection ends.

[0115] Step 818, close the relay.

[0116] Among them, the IIC acquisition is the signal acquired by the processing chip, the IO acquisition is the signal acquired by the first disconnection, and the AD value is the voltage value acquired by the acquisition.

[0117] Specifically, in the first state, let the total voltage of the energy storage battery be U0, the voltage at the second end of the second resistor be U1, and the voltage at the first end of the fifth resistor be u1, then:

[0118]

[0119] Among them, I1 is the current value of the upper bridge arm, and I2 is the current value of the lower bridge arm, then:

[0120]

[0121] Among them, the first formula is expressed as follows:

[0122]

[0123] In the first state, let the total voltage of the energy storage battery be U, the voltage at the second end of the second resistor be U2, and the voltage at the first end of the fifth resistor be u2, then:

[0124]

[0125] Among them, I3 is the current value of the upper bridge arm, and I4 is the current value of the lower bridge arm, then:

[0126]

[0127] Among them, the second formula is expressed as follows:

[0128]

[0129] R can be calculated based on the first and second formulas - and R + .

[0130] Wherein, let R2+R3 / / R4+R5=A, wherein R2+R3 / / R4+R5 represents that the second resistor and the third resistor are connected in series, and the fifth resistor and the fifth resistor connected in series are connected in parallel, and the resistance value after parallel connection is represented by A, then R + and R - It is expressed as follows:

[0131]

[0132] The microcontroller unit also obtains u1 and u2 by processing the chip to calculate another set of R + and R - , and the detected resistance should be no less than 1000Ω / V. The two sets of data are backed up to ensure the reliability of the insulation resistance.

[0133] In this embodiment, if the energy storage battery leaks electricity and the leakage cannot be identified, there is a risk that the energy storage battery will discharge to the human body, which can easily cause a serious accident that threatens life safety.

[0134] In the embodiment of the present invention, a new unbalanced bridge test method is proposed, which can more reliably calculate the insulation resistance of the positive and negative electrodes of the energy storage battery to the reference ground. At the same time, a redundant acquisition circuit is designed to calculate the insulation resistance, and the insulation resistance of the energy storage battery is backed up. Even if one of the insulation detection fails, it can ensure that the microcontroller unit obtains the insulation resistance of the energy storage battery by processing the acquisition value of the chip to ensure the safety of the energy storage device.

[0135] In some embodiments, optionally, the first switch S1 , the second switch S2 , and the third switch S3 are optocoupler relays.

[0136] In this embodiment, the optocoupler relay has a voltage isolation effect. Therefore, when the optocoupler relay is used, the reliability of the detection circuit 100 for the energy storage battery can be improved.

[0137] In one embodiment, if Figure 4 As shown, the present invention provides an energy storage device 200, including: an energy storage battery 202; and a detection circuit 100 for an energy storage battery as described in any one of the above.

[0138] In this embodiment, the energy storage device 200 supplies power or charges the energy storage battery 202 via the positive output terminal PACK+.

[0139] The term "first" or "second" in the specification and claims of the present application may include one or more of the features explicitly or implicitly. In the textual description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0140] In the text description of the present invention, it is understood that, except for explicit provisions and limitations, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be fixed connection, detachable connection, or integral connection; it can be mechanical structure connection or electrical connection; it can be direct connection between the two, or indirect connection between the two through an intermediate medium, or it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0141] In the claims, specification and drawings of the present invention, the description of the terms "one embodiment", "some embodiments", "specific embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In the claims, specification and drawings of the present invention, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0142] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A detection circuit for an energy storage battery, characterized in that: include: a first resistor; a second resistor, wherein a first end of the second resistor is connected to a second end of the first resistor, and a second end of the second resistor is connected to a reference ground; a voltage divider circuit, wherein a first end of the voltage divider circuit is connected to a second end of the second resistor, and a second end of the voltage divider circuit is connected to a negative electrode of an energy storage battery; a first switch, wherein a first end of the first switch is connected to the positive electrode of the energy storage battery, and a second end of the first switch is connected to the first end of the first resistor; a second switch, wherein a first end of the second switch is connected to a second end of the first resistor; a third resistor, wherein a first end of the third resistor is connected to a second end of the second switch, and a second end of the third resistor is connected to a negative electrode of the energy storage battery; A micro control unit is connected to the output end of the voltage divider circuit and is used to determine the first insulation resistance of the energy storage battery according to the voltage value output by the output end of the voltage divider circuit when the first switch and the second switch are in different conduction states.

2. The detection circuit for energy storage battery according to claim 1, characterized in that: The micro control unit is specifically used for: Acquire a first voltage value outputted by an output terminal of the voltage divider circuit in a first state, wherein in the first state, the first switch is in an on state and the second switch is in an off state; Acquire a second voltage value outputted by the output terminal of the voltage divider circuit in a second state, wherein in the second state, the first switch is in an off state and the second switch is in an on state; A first insulation resistance of the energy storage battery is determined based on the first voltage value and the second voltage value.

3. The detection circuit for energy storage battery according to claim 1, characterized in that: The micro control unit is also used for: Based on the first insulation resistance being less than a first threshold, outputting first abnormal information; Based on the first insulation resistance being greater than or equal to a first threshold, outputting no abnormality information; The first abnormality information is used to indicate that the insulation resistance of the energy storage battery is abnormal, and the non-abnormality information is used to indicate that the insulation resistance of the energy storage battery is normal.

4. The detection circuit for energy storage battery according to claim 2, characterized in that: The voltage divider circuit comprises: a fourth resistor, a first end of the fourth resistor being connected to a second end of the second resistor; a fifth resistor, wherein a first end of the fifth resistor is connected to a second end of the fourth resistor, and a second end of the fifth resistor is connected to a negative electrode of the energy storage battery; Wherein, the first end of the fifth resistor is the output end of the voltage divider circuit.

5. The detection circuit for energy storage battery according to claim 4, characterized in that: The detection circuit for the energy storage battery also includes: a processing chip, wherein a first end of the processing chip is connected to a first end of the fifth resistor, a second end of the processing chip is connected to a second end of the fifth resistor, and an output end of the processing chip is connected to the micro control unit; The micro control unit is also used for: Acquire a first differential voltage output by the processing chip in the first state and a second differential voltage output by the processing chip in the second state; A second insulation resistance of the energy storage battery is determined based on the first differential voltage and the second differential voltage.

6. The detection circuit for energy storage battery according to claim 5, characterized in that: The micro control unit is also used for: Obtaining an insulation resistance difference between the first insulation resistance and the second insulation resistance; Based on the insulation resistance difference being less than or equal to a second threshold, determining that the first insulation resistance and the second insulation resistance are valid detection results; Outputting first abnormal information based on that the first insulation resistance value and / or the second insulation resistance value is less than a first threshold value; Outputting no abnormality information based on that the first insulation resistance value and / or the second insulation resistance value is greater than or equal to a first threshold value; The first abnormality information is used to indicate that the insulation resistance of the energy storage battery is abnormal, and the non-abnormality information is used to indicate that the insulation resistance of the energy storage battery is normal.

7. The detection circuit for energy storage battery according to claim 6, characterized in that: The micro control unit is also used for: Determining that the first insulation resistance is an invalid detection result based on the insulation resistance difference being greater than a second threshold; and When the first insulation resistance is an invalid detection result, outputting second abnormal information; The second abnormal information is used to indicate that a first port is abnormal, and the first port is a port where the micro control unit is connected to an output end of the voltage divider circuit.

8. The detection circuit for energy storage battery according to claim 2, characterized in that: The detection circuit for the energy storage battery also includes: a third switch connected in series between the second end of the second resistor and the reference ground; In the first state and the second state, the third switch is in an on state.

9. The detection circuit for energy storage battery according to claim 8, characterized in that: The first switch, the second switch and the third switch are optocoupler relays.

10. An energy storage device, characterized in that: include: Energy storage batteries; A detection circuit for an energy storage battery as claimed in any one of claims 1 to 9.

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