Insulation detection circuit and electric automobile

Abstract

The embodiment of the utility model provides an insulation detection circuit and an electric vehicle, and belongs to the technical field of battery circuit detection. The insulation detection circuit is applied to at least two battery packs to be detected. The insulation detection circuit comprises an upper bridge arm test module, a lower bridge arm test module and a control module, the control module is used for adjusting a second connection state between the upper bridge arm test module and each to-be-tested battery pack based on a first connection state between at least two to-be-tested battery packs, and adjusting a third connection state between the lower bridge arm test module and each to-be-tested battery pack; the upper bridge arm test module is used for outputting an upper bridge arm test voltage according to the second connection state; the lower bridge arm test module is used for outputting a lower bridge arm test voltage according to the third connection state; the control module is also used for determining an insulation test result of each to-be-tested battery pack according to the upper bridge arm test voltage and the lower bridge arm test voltage. According to the embodiment of the invention, insulation detection of a plurality of battery packs can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery circuit detection, and particularly relates to an insulation detection circuit and an electric vehicle. BACKGROUND

[0002] In the production and use of electric vehicles, insulation detection of battery packs of the electric vehicles is an important link. However, the current insulation detection has limitations. For example, the current insulation detection circuit can only detect the insulation resistance of a single battery pack, and it is difficult to detect the insulation resistance in the case that the electric vehicle has multiple battery packs, and it is difficult to be applied to application environments in which multiple battery packs have different connection relationships, such as series connection, parallel connection or independent use of the battery packs.

[0003] Therefore, how to realize insulation detection of multiple battery packs has become a technical problem to be solved. CONTENT OF THE UTILITY MODEL

[0004] The main purpose of the embodiments of the present application is to provide an insulation detection circuit and an electric vehicle, which aims to realize insulation detection of multiple battery packs.

[0005] To achieve the above purpose, a first aspect of the embodiments of the present application provides an insulation detection circuit applied to at least two battery packs to be detected, and the insulation detection circuit comprises an upper bridge arm test module, a lower bridge arm test module and a control module.

[0006] The control module is electrically connected to the upper bridge arm test module and the lower bridge arm test module, and the upper bridge arm test module is electrically connected to the lower bridge arm test module. Each battery pack to be detected is electrically connected to the upper bridge arm test module and the lower bridge arm test module.

[0007] The control module is configured to adjust a second connection state between the upper bridge arm test module and each battery pack to be detected and adjust a third connection state between the lower bridge arm test module and each battery pack to be detected based on a first connection state between the at least two battery packs to be detected.

[0008] The upper bridge arm test module is configured to output an upper bridge arm test voltage according to the second connection state, and the lower bridge arm test module is configured to output a lower bridge arm test voltage according to the third connection state.

[0009] The control module is further configured to determine an insulation test result of each battery pack to be detected according to the upper bridge arm test voltage and the lower bridge arm test voltage.

[0010] In some embodiments, the upper bridge arm test module comprises a first test switch module and a first voltage division test module, and the lower bridge arm test module comprises a second test switch module and a second voltage division test module.

[0011] The first test switch module is electrically connected with the first voltage division test module and the second test switch module, the second test switch module is electrically connected with the second voltage division test module, the first voltage division test module is electrically connected with the second voltage division test module, and the control module is electrically connected with the first voltage division test module and the second voltage division test module;

[0012] The control module is configured to adjust a second connection state between the first test switch module and each of the battery packs to be tested and adjust a third connection state between the second test switch module and each of the battery packs to be tested based on the first connection state, the first voltage division test module is configured to output an upper bridge arm test voltage according to the second connection state, and the second voltage division test module is configured to output a lower bridge arm test voltage according to the third connection state;

[0013] The control module is further configured to calculate an insulation resistance of each of the battery packs to be tested according to the upper bridge arm test voltage and the lower bridge arm test voltage and determine an insulation test result of each of the battery packs to be tested.

[0014] In some embodiments, the insulation detection circuit further comprises a total voltage test module and a power supply module.

[0015] The total voltage test module and the power supply module are connected in parallel, the total voltage test module is connected in parallel with at least one of the battery packs to be tested, and the control module is electrically connected with the total voltage test module.

[0016] The total voltage test module is configured to collect a total test voltage, and the control module is further configured to calculate an insulation resistance of each of the battery packs to be tested based on the total test voltage, the upper bridge arm test voltage and the lower bridge arm test voltage, so as to determine an insulation test result of each of the battery packs to be tested.

[0017] In some embodiments, the first connection state is used to represent a connection state between at least two of the battery packs to be tested, and the first connection state is any one of an independent state, a parallel state or a series state; the second connection state represents a state of the first test switch module, and the second connection state is any one of an open state or a closed state; and the third connection state represents a state of the second test switch module, and the third connection state is any one of an open state or a closed state.

[0018] When the second connection state is the open state and the third connection state is the open state, the control module collects a total test voltage output by the total voltage test module and collects a first lower bridge arm test voltage output by the second voltage division test module.

[0019] In the second connection state is the closed state, and the third connection state is the disconnected state, the control module collects the second upper bridge arm test voltage output by the first voltage division test module, and collects the second lower bridge arm test voltage output by the second voltage division test module;

[0020] The control module is further configured to calculate a first upper bridge arm test voltage according to the total test voltage and the first lower bridge arm test voltage, and perform a simultaneous calculation according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the second upper bridge arm test voltage and the second lower bridge arm test voltage to obtain an insulation test result of the battery pack under test.

[0021] In some embodiments, the total voltage test module includes a first sampling resistor and a second sampling resistor; the first voltage division test module includes a fifth sampling resistor; the second voltage division test module includes a third sampling resistor and a fourth sampling resistor; the first test switch module includes a first switch and a seventh sampling resistor; the second test switch module includes a second switch and a sixth sampling resistor; and the power supply module includes a first power supply.

[0022] The first sampling resistor and the second sampling resistor are connected in series, the third sampling resistor and the fourth sampling resistor are connected in series, the first switch and the seventh sampling resistor are connected in series, and the second switch and the sixth sampling resistor are connected in series.

[0023] In some embodiments, when the first connection state is the parallel state or the series state, the total voltage test module further includes an eighth sampling resistor and a ninth sampling resistor; the first voltage division test module further includes a twelfth sampling resistor, the second voltage division test module further includes a tenth sampling resistor and an eleventh sampling resistor, the first test switch module further includes a third switch and a fourteenth sampling resistor; the second test switch module further includes a fourth switch and a thirteenth sampling resistor; and the power supply module further includes a second power supply.

[0024] The eighth sampling resistor and the ninth sampling resistor are connected in series, the tenth sampling resistor and the eleventh sampling resistor are connected in series, the third switch and the fourteenth sampling resistor are connected in series, and the fourth switch and the thirteenth sampling resistor are connected in series.

[0025] In some embodiments, when the first connection state is the parallel state, the first power supply and the second power supply are connected in parallel.

[0026] The first sampling resistor is electrically connected to the eighth sampling resistor, and the third sampling resistor is electrically connected to the tenth sampling resistor.

[0027] In some embodiments, when the first connection state is the series state, the first power supply and the second power supply are connected in series.

[0028] The sixth sampling resistor is electrically connected with the thirteenth sampling resistor, and the seventh sampling resistor is electrically connected with the fourteenth sampling resistor.

[0029] In some embodiments, when the second connection state is the open state and the third connection state is the open state, the control module collects the total test voltage output by the total voltage test module and collects the first lower bridge arm test voltage output by the second voltage division test module;

[0030] When the second connection state is the open state and the third connection state is the closed state, the control module collects the third upper bridge arm test voltage output by the first voltage division test module and collects the third lower bridge arm test voltage output by the second voltage division test module;

[0031] When the first connection state is the independent state, the control module calculates the first upper bridge arm test voltage according to the total test voltage and the first lower bridge arm test voltage, and performs simultaneous calculation according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the third upper bridge arm test voltage and the third lower bridge arm test voltage to determine the insulation test result of the battery pack to be tested.

[0032] To achieve the above-mentioned purpose, a second aspect of the embodiment of the present application provides an electric vehicle, which comprises the insulation detection circuit of the first aspect and at least two battery packs to be tested.

[0033] The insulation detection circuit is electrically connected with the at least two battery packs to be tested.

[0034] The insulation detection circuit and the electric vehicle provided by the present application can realize the insulation detection of multiple battery packs to be tested, and are suitable for application scenarios where multiple battery packs to be tested have different connection relationships, thereby improving the flexibility of the insulation detection circuit. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is a module block diagram of the insulation detection circuit provided by an embodiment of the present application;

[0036] Figure 2 is a module block diagram of the insulation detection circuit provided by another embodiment of the present application;

[0037] Figure 3 is a module block diagram of the insulation detection circuit provided by another embodiment of the application;

[0038] Figure 4 is a circuit principle diagram of the insulation detection circuit provided by an embodiment of the application;

[0039] Figure 5 is a circuit principle diagram of the insulation detection circuit provided by another embodiment of the application;

[0040] Figure 6 is a circuit principle diagram of the insulation detection circuit provided by another embodiment of the application;

[0041] Figure 7 is a module block diagram of the electric vehicle provided by an embodiment of the application.

[0042] The figure mark: the battery pack to be measured 100;The upper bridge arm test module 200;The lower bridge arm test module 300;The control module 400;The total voltage test module 500;The power module 600;The first test switch module 210;The first voltage division test module 220;The second test switch module 310;The second voltage division test module 320;The first power supply U1;The second power supply U2;The first switch S1;The second switch S2;The third switch S3;The fourth switch S4;The first sampling resistor R1;The second sampling resistor R2;The third sampling resistor R3;The fourth sampling resistor R4;The fifth sampling resistor R5;The sixth sampling resistor R6;The seventh sampling resistor R7;The eighth sampling resistor R8;The ninth sampling resistor R9;The tenth sampling resistor R10;The eleventh sampling resistor R11;The twelfth sampling resistor R12;The thirteenth sampling resistor R13;The fourteenth sampling resistor R14. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the application more clear, the application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the application, and not used to limit the application.

[0044] It should be noted that although the functional modules are divided in the device schematic diagram, and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification and claims and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to be limiting of this application.

[0046] First, the terms involved in the present application are analyzed:

[0047] Insulation resistance: refers to the resistance value between the positive electrode and the negative electrode of the battery pack and the low-voltage ground. Insulation resistance is usually used to measure the insulation performance of electrical equipment.

[0048] The insulation detection circuit and electric vehicle provided by the embodiments of the present application are specifically described through the following embodiments. First, the insulation detection circuit in the embodiments of the present application is described.

[0049] Figure 1 is an optional module block diagram of the insulation detection circuit provided by the embodiments of the present application. The insulation detection circuit is applied to at least two battery packs 100 to be tested, and the insulation detection circuit comprises an upper bridge arm test module 200, a lower bridge arm test module 300 and a control module 400;

[0050] The control module 400 is electrically connected to the upper bridge arm test module 200 and the lower bridge arm test module 300, the upper bridge arm test module 200 is electrically connected to the lower bridge arm test module 300, and each battery pack 100 to be tested is electrically connected to the upper bridge arm test module 200 and the lower bridge arm test module 300;

[0051] The control module 400 is configured to adjust a second connection state between the upper bridge arm test module 200 and each battery pack 100 to be tested, and adjust a third connection state between the lower bridge arm test module 300 and each battery pack 100 to be tested, based on a first connection state between the at least two battery packs 100 to be tested;

[0052] The upper bridge arm test module 200 is configured to output an upper bridge arm test voltage according to the second connection state; and the lower bridge arm test module 300 is configured to output a lower bridge arm test voltage according to the third connection state.

[0053] The control module 400 is further configured to determine an insulation test result of each battery pack 100 to be tested according to the upper bridge arm test voltage and the lower bridge arm test voltage.

[0054] The beneficial effects of the embodiments of the present application include but are not limited to: the control module 400 adjusts the second connection state between the upper bridge arm test module 200 and each of the battery packs 100 under test based on the first connection state between the at least two battery packs 100 under test, and adjusts the third connection state between the lower bridge arm test module 300 and each of the battery packs 100 under test; the upper bridge arm test module 200 outputs the upper bridge arm test voltage according to the second connection state; the lower bridge arm test module 300 outputs the lower bridge arm test voltage according to the third connection state; then, the control module 400 determines the insulation test result of each of the battery packs 100 under test according to the upper bridge arm test voltage and the lower bridge arm test voltage, which can realize insulation detection of multiple battery packs 100 under test, is suitable for application scenarios where multiple battery packs 100 under test exist different connection relationships, thereby improving the flexibility of the insulation detection circuit.

[0055] It should be noted that the battery pack 100 under test can refer to the battery of an electric vehicle. For example, in an electric vehicle, the battery pack 100 under test is used to power the electric vehicle. Specifically, the battery pack 100 under test can be a lithium battery.

[0056] In some embodiments, the at least two battery packs 100 under test refer to that the same electric vehicle includes at least two battery packs 100 under test. It can be understood that in the current electric vehicle, a single battery pack can be used for power supply. However, in the use process of the battery, the battery pack may be overcharged or overdischarged, resulting in damage to the battery pack, and thus causing the electric vehicle to need to be repaired and cannot continue to be used. Or, when charging the battery pack of the electric vehicle, the charging pile may not match the capacity and voltage of the battery pack, thereby affecting the use of the electric vehicle. The embodiments of the present application aim at the above problems, and use at least two battery packs 100 under test to power the electric vehicle to meet different application scenarios of the electric vehicle in use.

[0057] It should be noted that in the process of safety detection of the battery pack, insulation detection is an indispensable detection item. In the scenario where the electric vehicle includes at least two battery packs 100 under test, any two battery packs 100 under test can be connected in series, connected in parallel, or used independently (i.e. not connected), and the traditional insulation detection scheme cannot effectively detect the insulation resistance of the battery packs 100 under test in the above scenario. For this purpose, the insulation detection circuit proposed in the embodiments of the present application can be applied to the above scenario where any two battery packs 100 under test exist different connection relationships, and realizes insulation resistance detection of each of the battery packs 100 under test.

[0058] Specifically, the control module 400 can be a host computer, a controller, or the like. For example, the control module 400 can be a CPU (Central Processing Unit, CPU for short), an MCU (Microcontroller Unit, MCU for short), a PLC (Programmable Logic Controller, PLC for short), or the like.

[0059] In some embodiments, the second connection state between the upper bridge arm test module 200 and each battery pack 100 under test can also be manually adjusted, or the third connection state between the lower bridge arm test module 300 and each battery pack 100 under test can also be manually adjusted.

[0060] In some embodiments, it should be noted that the upper bridge arm test module 200 is connected in series with the lower bridge arm test module 300, the battery pack 100 under test is connected in series with the upper bridge arm test module 200, and the battery pack 100 under test is connected in series with the lower bridge arm test module 300. The control module 400 is communicatively connected to the upper bridge arm test module 200 and the lower bridge arm test module 300, which can be wired or wireless communication connection, and the embodiments of the present application do not limit this.

[0061] Please refer to Figure 2 In some embodiments, the upper bridge arm test module 200 includes a first test switch module 210 and a first voltage division test module 220, and the lower bridge arm test module 300 includes a second test switch module 310 and a second voltage division test module 320.

[0062] The first test switch module 210 is electrically connected to the first voltage division test module 220 and the second test switch module 310, the second test switch module 310 is electrically connected to the second voltage division test module 320, the first voltage division test module 220 is electrically connected to the second voltage division test module 320, and the control module 400 is electrically connected to the first voltage division test module 220 and the second voltage division test module 320.

[0063] The control module 400 is configured to adjust the second connection state between the first test switch module 210 and each battery pack 100 under test based on the first connection state, and adjust the third connection state between the second test switch module 310 and each battery pack 100 under test. The first voltage division test module 220 is configured to output an upper bridge arm test voltage according to the second connection state, and the second voltage division test module 320 is configured to output a lower bridge arm test voltage according to the third connection state.

[0064] The control module 400 is further configured to calculate the insulation resistance of each battery pack 100 under test according to the upper bridge arm test voltage and the lower bridge arm test voltage, and determine the insulation test result of each battery pack 100 under test.

[0065] The advantage of this embodiment is that, by controlling module 400, based on the first connection state, adjusting the second connection state between the first test switch module 210 and each battery pack 100 under test, and adjusting the third connection state between the second test switch module 310 and each battery pack 100 under test, the insulation test result of each battery pack 100 under test is determined, the insulation detection of multiple battery packs 100 under test can be realized, which is suitable for application scenarios where multiple battery packs 100 under test exist different connection relationships, thereby improving the flexibility of the insulation detection circuit.

[0066] It should be noted that the insulation resistance of the battery pack 100 under test refers to the resistance value between the positive electrode and the negative electrode of the battery pack 100 under test and the low-voltage ground. The insulation test result refers to the insulation test result obtained by comparing the insulation resistance of the battery pack 100 under test with the preset standard resistance threshold range. If the insulation resistance of the battery pack 100 under test belongs to the standard resistance threshold range, the insulation test result is normal; if the insulation resistance of the battery pack 100 under test does not belong to the standard resistance threshold range, the insulation test result is abnormal. In an embodiment, the standard resistance threshold range can be 178 megaohms to 284 megaohms, or the standard resistance threshold range can be set or modified according to requirements, and the present application embodiment does not limit this.

[0067] In an embodiment, it should be noted that the first test switch module 210 is connected in parallel with the first voltage division test module 220, and the second test switch module 310 is connected in parallel with the second voltage division test module 320.

[0068] Please refer to Figure 3 In some embodiments, the insulation detection circuit further comprises a total voltage test module 500 and a power supply module 600;

[0069] The total voltage test module 500 and the power supply module 600 are connected in parallel, the total voltage test module 500 and at least one battery pack 100 under test are connected in parallel, and the control module 400 is electrically connected to the total voltage test module 500.

[0070] The total voltage test module 500 is used to collect a total test voltage, and the control module 400 is further used to calculate the insulation resistance of each battery pack 100 under test based on the total test voltage, the upper bridge arm test voltage and the lower bridge arm test voltage, so as to determine the insulation test result of each battery pack 100 under test.

[0071] The embodiment has the advantages that the total test voltage is collected by the total voltage test module 500, the insulation resistance of each battery pack 100 to be tested is calculated by the control module 400 according to the total test voltage, the upper bridge arm voltage and the lower bridge arm test voltage, the insulation detection of multiple battery packs 100 to be tested can be realized, the application scenarios in which multiple battery packs 100 to be tested exist different connection relationships are applicable, and therefore the flexibility of the insulation detection circuit is improved.

[0072] In some embodiments, it should be noted that the total voltage test module 500 is connected in parallel with the power supply module 600, and the power supply module 600 is connected in parallel with the battery pack 100 to be tested. The control module 400 is in communication connection with the total voltage test module 500, which can be wired or wireless communication connection, and the application embodiments do not limit this.

[0073] In some embodiments, the first connection state is used to represent the connection state between the at least two battery packs 100 to be tested, and the first connection state is any one of the following: an independent state, a parallel state or a series state; the second connection state represents the state of the first test switch module 210, and the second connection state is any one of the following: an open state or a closed state; the third connection state represents the state of the second test switch module 310, and the third connection state is any one of the following: an open state or a closed state.

[0074] When the second connection state is the open state and the third connection state is the open state, the control module 400 collects the total test voltage output by the total voltage test module 500 and collects the first lower bridge arm test voltage output by the second voltage division test module 320;

[0075] When the second connection state is the closed state and the third connection state is the open state, the control module 400 collects the second upper bridge arm test voltage output by the first voltage division test module 220 and collects the second lower bridge arm test voltage output by the second voltage division test module 320;

[0076] The control module 400 is further configured to calculate the first upper bridge arm test voltage according to the total test voltage and the first lower bridge arm test voltage, and perform simultaneous calculation according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the second upper bridge arm test voltage and the second lower bridge arm test voltage to obtain the insulation test result of the battery pack 100 to be tested.

[0077] The embodiment has the advantages that according to the first connection state between the two battery packs 100 to be tested, such as the independent state, the parallel state or the series state, the insulation test result of the battery pack 100 to be tested is obtained by calculation according to the total voltage test module 500, the first voltage division test module 220 and the second voltage division test module 320, the insulation detection of the plurality of battery packs 100 to be tested can be realized, the application scenarios in which the plurality of battery packs 100 to be tested exist different connection relationships are suitable, and therefore the flexibility of the insulation detection circuit is improved.

[0078] Please refer to Figure 4 In some embodiments, the total voltage test module 500 includes the first sampling resistor R1 and the second sampling resistor R2; the first voltage division test module 220 includes the fifth sampling resistor R5; the second voltage division test module 320 includes the third sampling resistor R3 and the fourth sampling resistor R4; the first test switch module 210 includes the first switch S1 and the seventh sampling resistor R7; the second test switch module 310 includes the second switch S2 and the sixth sampling resistor R6; and the power supply module 600 includes the first power supply U1.

[0079] The first sampling resistor R1 and the second sampling resistor R2 are connected in series, the third sampling resistor R3 and the fourth sampling resistor R4 are connected in series, the first switch S1 and the seventh sampling resistor R7 are connected in series, and the second switch S2 and the sixth sampling resistor R6 are connected in series.

[0080] The embodiment has the advantages that the insulation detection circuit is composed of the total voltage test module 500, the first voltage division test module 220, the second voltage division test module 320, the first test switch module 210, the second test switch module 310 and the power supply module 600; and the insulation detection of each battery pack 100 to be tested can be realized by the insulation detection circuit.

[0081] In some embodiments, it should be noted that in Figure 4 In some embodiments, the first battery pack to be tested includes the first cell resistor Rp1 and the second cell resistor Rn1, and the second battery pack to be tested includes the third cell resistor Rp2 and the fourth cell resistor Rn2. One end of the fifth switch is grounded, and the other end is electrically connected between the first cell resistor Rp1 and the second cell resistor Rn1.

[0082] In some embodiments, the insulation resistance of each battery pack 100 to be tested can be calculated according to the following method: the fifth switch is closed, the resistance voltage Vu11 of the second sampling resistor R2 is detected, and the resistance voltage Vn11 of the third sampling resistor R3 is detected; and the voltage U11, the voltage Un11 and the voltage Up11 are calculated according to the following formulas (1) to (3):

[0083] U11=(R1+R2)*Vu11 / R2, equation (1);

[0084] Un11=(R3+R4)*Vn11 / R3, equation (2);

[0085] Up11=U11-Un11, equation (3);

[0086] Close the first switch S1 and open the second switch S2, equation (4) is constructed as follows:

[0087] Up11 / (Rp1 / / R5)=Un11 / (Rn1 / / R6), equation (4);

[0088] Wherein, Rp1 / / R5 represents the overall parallel resistance value of the first cell resistance Rp1 and the fifth sampling resistance R5 in parallel; Rn1 / / R6 represents the overall parallel resistance value of the second cell resistance Rn1 and the sixth sampling resistance R6 in parallel; the overall parallel resistance value can be calculated by the parallel resistance value calculation formula.

[0089] Close the first switch S1 and open the second switch S2, equation (5) is constructed as follows:

[0090] Up12 / (Rp1 / / R5 / / R7)=Un12(Rn1 / / R6), equation (5);

[0091] Wherein, Rp1 / / R5 / / R7 represents the overall parallel resistance value of the first cell resistance Rp1, the fifth sampling resistance R5 and the seventh sampling resistance R7 in parallel. It can be understood that the voltage Up12 and the voltage Un12 are the resistance voltage Vu12 of the second sampling resistance R2 and the resistance voltage Vn12 of the third sampling resistance R3 detected under the condition that the first switch S1 is closed and the second switch S2 is opened, then Vu11 in equation (1) and equation (2) is replaced by Vu12, and Vn11 is replaced by Vn12, and thus calculated.

[0092] The above equations (1) to (5) are solved simultaneously to calculate the first cell resistance Rp1 and the second cell resistance Rn1, so as to determine the insulation resistance of the first battery pack to be measured.

[0093] In another embodiment, the first switch S1 can be opened and the second switch S2 can be closed, equation (6) is constructed as follows:

[0094] Up12 / (Rp1 / / R5 / / R7)=Un12(Rn1 / / R6 / / R8), equation (6);

[0095] Wherein, Rn1 / / R6 / / R8 represents the overall parallel resistance value of the second cell resistance Rn1, the sixth sampling resistance R6 and the eighth sampling resistance R8 in parallel.

[0096] The first cell resistance Rp1 and the second cell resistance Rn1 can be calculated by simultaneously solving equations (1), (2), (3), (5) and (6), so as to determine the insulation resistance of the first battery pack to be tested.

[0097] It can be understood that the insulation resistance calculation method of the third cell resistance Rp2 and the fourth cell resistance Rn2 is basically the same as the insulation resistance calculation method of the first cell resistance Rp1 and the second cell resistance Rn1 described above, and will not be repeated here.

[0098] Please refer to Figure 5 and Figure 6 In some embodiments, when the first connection state is in parallel or series, the total voltage test module 500 further comprises an eighth sampling resistance R8 and a ninth sampling resistance R9; the first voltage division test module 220 further comprises a twelfth sampling resistance R12, the second voltage division test module 320 further comprises a tenth sampling resistance R10 and an eleventh sampling resistance R11, the first test switch module 210 further comprises a third switch S3 and a fourteenth sampling resistance R14; the second test switch module 310 further comprises a fourth switch S4 and a thirteenth sampling resistance R13; the power supply module 600 further comprises a second power supply U2.

[0099] The eighth sampling resistance R8 and the ninth sampling resistance R9 are connected in series, the tenth sampling resistance R10 and the eleventh sampling resistance R11 are connected in series, the third switch S3 and the fourteenth sampling resistance R14 are connected in series, and the fourth switch S4 and the thirteenth sampling resistance R13 are connected in series.

[0100] The advantages of this embodiment are that the insulation detection circuit is composed of the total voltage test module 500, the first voltage division test module 220, the second voltage division test module 320, the first test switch module 210, the second test switch module 310 and the power supply module 600; and the insulation detection of each battery pack to be tested 100 can be realized in the case that the first connection state between at least two battery packs to be tested 100 is in parallel or series.

[0101] Please refer to Figure 5 In some embodiments, when the first connection state is in parallel, the first power supply U1 and the second power supply U2 are connected in parallel.

[0102] The first sampling resistance R1 is electrically connected to the eighth sampling resistance R8, and the third sampling resistance R3 is electrically connected to the tenth sampling resistance R10.

[0103] The embodiment has the advantages that in the case that the first connection state between the at least two battery packs 100 to be tested is in parallel connection, the first power supply U1 and the second power supply U2 are connected in parallel, the first sampling resistor R1 is electrically connected with the eighth sampling resistor R8, and the third sampling resistor R3 is electrically connected with the tenth sampling resistor R10, so as to realize insulation detection of the two battery packs 100 connected in parallel.

[0104] Please refer to Figure 6 In some embodiments, in the case that the first connection state is in series connection, the first power supply and the second power supply are connected in series.

[0105] The sixth sampling resistor is electrically connected with the thirteenth sampling resistor, and the seventh sampling resistor is electrically connected with the fourteenth sampling resistor.

[0106] The embodiment has the advantages that in the case that the first connection state between the at least two battery packs 100 to be tested is in series connection, the first power supply U1 and the second power supply U2 are connected in series, the sixth sampling resistor R6 is electrically connected with the thirteenth sampling resistor R13, and the seventh sampling resistor R7 is electrically connected with the fourteenth sampling resistor R14, so as to realize insulation detection of the two battery packs 100 connected in series.

[0107] In some embodiments, in the case that the second connection state is in open state, and the third connection state is in open state, the control module 400 collects the total test voltage output by the total voltage test module 500, and collects the first lower bridge arm test voltage output by the second voltage division test module 320;

[0108] In the case that the second connection state is in open state, and the third connection state is in closed state, the control module 400 collects the third upper bridge arm test voltage output by the first voltage division test module 220, and collects the third lower bridge arm test voltage output by the second voltage division test module 320;

[0109] In the case that the first connection state is in independent state, the control module 400 calculates the first upper bridge arm test voltage according to the total test voltage and the first lower bridge arm test voltage, and performs simultaneous calculation according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the third upper bridge arm test voltage and the third lower bridge arm test voltage, so as to determine the insulation test result of the battery pack 100 to be tested.

[0110] The embodiment has the advantages that the simultaneous calculation according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the third upper bridge arm test voltage and the third lower bridge arm test voltage determines the insulation test result of the battery pack 100 to be tested, which can realize insulation detection of multiple battery packs 100 to be tested, is suitable for application scenarios in which multiple battery packs 100 to be tested have different connection relationships, and thus improves the flexibility of the insulation detection circuit.

[0111] Please refer toFigure 7 The embodiment of the application further provides an electric vehicle, comprising the insulation detection circuit and at least two battery packs 100 to be detected.

[0112] In some embodiments, it should be noted that the two battery packs 100 to be detected are connected in series, so that the overall voltage of the battery pack is increased. For example, when the electric vehicle is charging, the connection relationship of the two battery packs 100 to be detected can be switched between the independent state and the series state, so as to meet the voltage requirements of different chargers, so that the battery pack can be adapted to different chargers. By connecting the two battery packs 100 to be detected in series, the charging current can be reduced, so as to avoid the situation that the wire harness connected between the battery pack and the charger is overheated during charging, and the safety of the battery pack is improved.

[0113] In some embodiments, it should be noted that the two battery packs 100 to be detected are connected in parallel, so that the overall capacity of the battery pack is increased, thereby increasing the power supply time of the battery pack and improving the endurance of the electric vehicle.

[0114] In some embodiments, if one of the battery packs 100 to be detected is damaged, the connection relationship of the two battery packs 100 to be detected can be switched to the independent state, that is, the damaged battery pack 100 to be detected is disconnected from other normal battery packs 100 to be detected, and the normal battery pack 100 to be detected is independently used to supply power to the electric vehicle.

[0115] In some embodiments, in addition to the electric vehicle, the insulation detection circuit can also be applied to an energy storage system. For example, the energy storage system comprises a shell, an insulation detection circuit and a large battery. The insulation detection circuit can be arranged between the large battery and the shell (or other ground terminal), and the insulation detection circuit is electrically connected between the large battery and the shell, so as to detect the insulation resistance of the large battery. The scope of the insulation detection circuit is not limited in the embodiment of the application.

[0116] The specific embodiments of the electric vehicle are basically the same as the specific embodiments of the insulation detection circuit described above, and will not be repeated here.

[0117] The embodiments described in the embodiments of the application are used to more clearly illustrate the technical solutions of the embodiments of the application, and do not constitute a limitation on the technical solutions provided by the embodiments of the application. It is known to those skilled in the art that, with the evolution of technology and the appearance of new application scenarios, the technical solutions provided by the embodiments of the application are also applicable to similar technical problems.

[0118] The apparatus embodiments described above are merely exemplary, and the units described as separate units can or can not be physically separate, i.e., can be located in one place, or can be distributed over multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment.

[0119] Those skilled in the art can understand that all or some of the steps in the method disclosed above, the functional modules / units in the system and the device can be implemented as software, firmware, hardware and appropriate combinations thereof.

[0120] The terms "first", "second", "third", "fourth" and the like in the description of the application and in the claims of the foregoing drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of the terms so

[0121] It should be understood that in this application, "at least one" means one or more, and "multiple" means two or more. "And / or" is used to describe the relationship between the associated objects, which means that there can be three relationships, for example, "A and / or B" can mean that there are three cases: only A, only B, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally represents that the associated objects before and after are in an "or" relationship. "At least one of the following" or the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c, can mean a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0122] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can be implemented by other manners. For example, the apparatus embodiments described above are merely illustrative, for example, the division of the above units is merely a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. The coupling or direct coupling or communication connection between the units or components shown or discussed can be indirect coupling or communication connection through some interfaces, apparatuses or units, and can be electrical, mechanical or other forms.

[0123] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they can be located in one place or distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0124] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0125] If the integrated unit is realized in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part of the prior art that makes a contribution or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method of each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program storage media.

[0126] The preferred embodiments of the embodiments of the present application are described above with reference to the accompanying drawings, but this does not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the rights of the embodiments of the present application.

Claims

1. An insulation detection circuit, characterized by comprising: The insulation detection circuit is applied to at least two battery packs to be tested, and comprises an upper bridge arm test module, a lower bridge arm test module and a control module. The control module is electrically connected to the upper bridge arm test module and the lower bridge arm test module, and the upper bridge arm test module is electrically connected to the lower bridge arm test module; each battery pack to be tested is electrically connected to the upper bridge arm test module and the lower bridge arm test module. The control module is configured to adjust a second connection state between the upper bridge arm test module and each battery pack to be tested and a third connection state between the lower bridge arm test module and each battery pack to be tested based on a first connection state between the at least two battery packs to be tested. The upper bridge arm test module is configured to output an upper bridge arm test voltage according to the second connection state, and the lower bridge arm test module is configured to output a lower bridge arm test voltage according to the third connection state. The control module is further configured to determine an insulation test result of each battery pack to be tested based on the upper bridge arm test voltage and the lower bridge arm test voltage.

2. The insulation detection circuit according to claim 1, characterized by The upper bridge arm test module comprises a first test switch module and a first voltage division test module, and the lower bridge arm test module comprises a second test switch module and a second voltage division test module. The first test switch module is electrically connected to the first voltage division test module and the second test switch module, the second test switch module is electrically connected to the second voltage division test module, the first voltage division test module is electrically connected to the second voltage division test module, and the control module is electrically connected to the first voltage division test module and the second voltage division test module. The control module is configured to adjust a second connection state between the first test switch module and each battery pack to be tested and a third connection state between the second test switch module and each battery pack to be tested based on the first connection state; the first voltage division test module is configured to output an upper bridge arm test voltage according to the second connection state; and the second voltage division test module is configured to output a lower bridge arm test voltage according to the third connection state. The control module is further configured to calculate an insulation resistance of each battery pack to be tested based on the upper bridge arm test voltage and the lower bridge arm test voltage, and determine an insulation test result of each battery pack to be tested.

3. The insulation detection circuit according to claim 2, characterized in that, The insulation detection circuit further comprises a total voltage test module and a power supply module. The total voltage test module and the power supply module are connected in parallel, the total voltage test module is connected in parallel to at least one battery pack to be tested, and the control module is electrically connected to the total voltage test module. The total voltage test module is configured to collect a total test voltage, and the control module is further configured to calculate an insulation resistance of each battery pack to be tested based on the total test voltage, the upper bridge arm test voltage and the lower bridge arm test voltage, so as to determine an insulation test result of each battery pack to be tested.

4. The insulation detection circuit according to claim 3, characterized in that, The first connection state is used to represent the connection state between at least two battery packs to be tested, and the first connection state is any one of the following: an independent state, a parallel state or a series state; the second connection state represents the state of the first test switch module, and the second connection state is any one of the following: an open state or a closed state; the third connection state represents the state of the second test switch module, and the third connection state is any one of the following: an open state or a closed state; When the second connection state is the open state and the third connection state is the open state, the control module collects a total test voltage output by the total voltage test module and collects a first lower bridge arm test voltage output by the second voltage division test module; When the second connection state is the closed state and the third connection state is the open state, the control module collects a second upper bridge arm test voltage output by the first voltage division test module and collects a second lower bridge arm test voltage output by the second voltage division test module; The control module is further used to calculate a first upper bridge arm test voltage according to the total test voltage and the first lower bridge arm test voltage, and perform simultaneous calculation according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the second upper bridge arm test voltage and the second lower bridge arm test voltage, so as to obtain an insulation test result of the battery pack to be tested.

5. The insulation detection circuit according to claim 4, characterized in that, The total voltage test module comprises a first sampling resistor and a second sampling resistor; the first voltage division test module comprises a fifth sampling resistor; the second voltage division test module comprises a third sampling resistor and a fourth sampling resistor; the first test switch module comprises a first switch and a seventh sampling resistor; the second test switch module comprises a second switch and a sixth sampling resistor; and the power supply module comprises a first power supply. The first sampling resistor and the second sampling resistor are connected in series, the third sampling resistor and the fourth sampling resistor are connected in series, the first switch and the seventh sampling resistor are connected in series, and the second switch and the sixth sampling resistor are connected in series.

6. The insulation detection circuit according to claim 5, characterized in that, When the first connection state is the parallel state or the series state, the total voltage test module further comprises an eighth sampling resistor and a ninth sampling resistor; the first voltage division test module further comprises a twelfth sampling resistor; the second voltage division test module further comprises a tenth sampling resistor and an eleventh sampling resistor; the first test switch module further comprises a third switch and a fourteenth sampling resistor; the second test switch module further comprises a fourth switch and a thirteenth sampling resistor; and the power supply module further comprises a second power supply. The eighth sampling resistor and the ninth sampling resistor are connected in series, the tenth sampling resistor and the eleventh sampling resistor are connected in series, the third switch and the fourteenth sampling resistor are connected in series, and the fourth switch and the thirteenth sampling resistor are connected in series.

7. The insulation detection circuit according to claim 6, characterized in that, When the first connection state is the parallel state, the first power supply and the second power supply are connected in parallel; The first sampling resistor is electrically connected to the eighth sampling resistor, and the third sampling resistor is electrically connected to the tenth sampling resistor.

8. The insulation detection circuit according to claim 6, characterized by When the first connection state is the series state, the first power supply and the second power supply are connected in series; The sixth sampling resistor is electrically connected with the thirteenth sampling resistor, and the seventh sampling resistor is electrically connected with the fourteenth sampling resistor.

9. The insulation detection circuit according to claim 4, characterized by When the second connection state is the open state and the third connection state is the open state, the control module collects a total test voltage output by the total voltage test module and collects a first lower bridge arm test voltage output by the second voltage division test module; When the second connection state is the open state and the third connection state is the closed state, the control module collects a third upper bridge arm test voltage output by the first voltage division test module and collects a third lower bridge arm test voltage output by the second voltage division test module; When the first connection state is the independent state, the control module calculates a first upper bridge arm test voltage according to the total test voltage and the first lower bridge arm test voltage, and determines an insulation test result of the battery pack to be tested by simultaneously calculating according to the first upper bridge arm test voltage, the first lower bridge arm test voltage, the third upper bridge arm test voltage and the third lower bridge arm test voltage.

10. An electric vehicle, characterized by The insulation detection circuit comprises: The insulation detection circuit is electrically connected with the at least two battery packs to be tested. The insulation detection circuit is electrically connected with the at least two battery packs to be tested.

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