A battery insulation resistance fast measurement circuit, device and measurement method

Abstract

The present invention provides a battery insulation resistance rapid measurement circuit, equipment and measurement method, which relates to the technical field of electric vehicle insulation resistance detection, and the circuit includes: a battery voltage detection module; a first voltage detection module; a second voltage detection module; a first discharge module connected in parallel with the first voltage detection module; a second discharge module connected in parallel with the second voltage detection module; a switching module connected with the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module; a control processing module connected with the battery voltage detection module, the first voltage detection module, the second voltage detection module and the switching module respectively. The first discharge module and the second discharge module can shorten the time taken for the equivalent capacitance to reach a steady state, and realize rapid measurement. At the same time, considering the battery voltage fluctuation, the equation is constructed to solve the positive electrode insulation resistance value and the negative electrode insulation resistance value, so as to avoid the measurement error caused by the battery voltage fluctuation and improve the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle insulation resistance detection, and in particular to a battery insulation resistance rapid measurement circuit, equipment and measurement method. Background Art

[0002] There is insulation resistance between the power battery and the ground in electric vehicles. Testing the insulation resistance is an important process to ensure the insulation safety of electric vehicles. The performance of insulation resistance is directly related to the life safety of passengers. The insulation resistance testing methods used by various automobile manufacturers are different, and the insulation resistance testing accuracy is also different.

[0003] In the existing insulation resistance measurement process, due to the equivalent capacitance between the positive and negative electrodes of the battery and the ground, the insulation resistance can only be accurately measured after the equivalent capacitance is charged and discharged to a steady state. At the same time, the insulation resistance also affects the charging and discharging time of the equivalent capacitance. When the insulation resistance is uncertain, the charging and discharging time of the equivalent capacitance is also uncertain. The existing method generally ensures that the steady state is reached by waiting for a long time, resulting in a long measurement time. Moreover, if the waiting time is insufficient, measurement deviation is very likely to occur, resulting in a decrease in the measurement accuracy of the insulation resistance. Summary of the invention

[0004] The present invention provides a battery insulation resistance rapid measurement circuit, equipment and measurement method, which are used to solve the defect of long insulation resistance measurement time of batteries in electric vehicles in the prior art and realize rapid insulation resistance measurement.

[0005] The present invention provides a battery insulation resistance fast measurement circuit, comprising:

[0006] A battery voltage detection module, used to connect to the positive and negative electrodes of the battery;

[0007] A first voltage detection module, used to be connected to the negative electrode of the battery and the ground;

[0008] A second voltage detection module, used to be connected to the positive electrode of the battery and the ground;

[0009] A first discharge module, connected in parallel with the first voltage detection module;

[0010] A second discharge module, connected in parallel with the second voltage detection module;

[0011] a switching module connected to the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module;

[0012] a control processing module, connected to the battery voltage detection module, the first voltage detection module, the second voltage detection module and the switching module respectively;

[0013] The switching module includes a first state and a second state, the first state turns on the first voltage detection module and the second discharge module and turns off the second voltage detection module and the first discharge module, and the second state turns on the second voltage detection module and the first discharge module and turns off the first voltage detection module and the second discharge module.

[0014] According to a battery insulation resistance rapid measurement circuit provided by the present invention, the switching module includes a first switch component, a second switch component, a third switch component and a fourth switch component, the first switch component is connected to the first voltage detection module, the second switch component is connected to the second voltage detection module, the third switch component is connected to the first discharge module, and the fourth switch component is connected to the second discharge module, the control processing module is connected to the controlled end of the first switch component, the controlled end of the second switch component, the controlled end of the third switch component and the controlled end of the fourth switch component, and the control processing module controls the first switch component and the fourth switch component to close and the second switch component and the third switch component to open, or controls the second switch component and the third switch component to close and the first switch component and the fourth switch component to open.

[0015] According to a battery insulation resistance fast measurement circuit provided by the present invention, the first voltage detection module includes a first voltage-dividing resistor, a second voltage-dividing resistor and a first voltage detection element, one end of the first voltage-dividing resistor is used to be connected to the negative electrode of the battery, the other end of the first voltage-dividing resistor is connected to one end of the second voltage-dividing resistor through the first switch element, the other end of the second voltage-dividing resistor is grounded, the first voltage detection element is connected to the first voltage-dividing resistor or the second voltage-dividing resistor, and the control processing module is connected to the first voltage detection element.

[0016] According to a battery insulation resistance fast measurement circuit provided by the present invention, the second voltage detection module includes a third voltage-dividing resistor, a fourth voltage-dividing resistor and a second voltage detection component, one end of the third voltage-dividing resistor is used to be connected to the positive electrode of the battery, the other end of the third voltage-dividing resistor is connected to one end of the fourth voltage-dividing resistor through the second switch component, the other end of the fourth voltage-dividing resistor is grounded, the second voltage detection component is connected to the third voltage-dividing resistor or the fourth voltage-dividing resistor, and the control processing module is connected to the second voltage detection component.

[0017] According to a battery insulation resistance fast measurement circuit provided by the present invention, the first discharge module includes a first discharge resistor, one end of the first discharge resistor is connected to the negative electrode of the battery through the third switch, and the other end of the first discharge resistor is grounded.

[0018] According to a battery insulation resistance fast measurement circuit provided by the present invention, the second discharge module includes a second discharge resistor, one end of the second discharge resistor is connected to the positive electrode of the battery through the fourth switch, and the other end of the second discharge resistor is grounded.

[0019] According to a battery insulation resistance fast measurement circuit provided by the present invention, the battery voltage detection module includes a fifth voltage-dividing resistor, a sixth voltage-dividing resistor and a third voltage detection component, one end of the fifth voltage-dividing resistor is connected to the negative electrode of the battery, the other end of the fifth voltage-dividing resistor is connected to one end of the sixth voltage-dividing resistor, one end of the sixth voltage-dividing resistor is connected to the positive electrode of the battery, the third voltage detection component is connected to the fifth voltage-dividing resistor or the sixth voltage-dividing resistor, and the control processing module is connected to the third voltage detection component.

[0020] A battery insulation resistance rapid measurement circuit provided according to the present invention further includes a grounding switch, the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module are all grounded through the grounding switch, and the control processing module is connected to the controlled end of the grounding switch.

[0021] The present invention also provides a measuring device, comprising the above-mentioned battery insulation resistance rapid measurement circuit, and also comprising a warning module, and the control processing module is connected to the warning module.

[0022] The present invention also provides a measurement method, which is applied to the above-mentioned battery insulation resistance fast measurement circuit or the above-mentioned measurement device, comprising:

[0023] The control processing module controls the switching module to switch to a first state, obtains a first detection voltage of the first voltage detection module and a first battery voltage of the battery voltage detection module, and establishes a first equation about the positive electrode insulation resistance and the negative electrode insulation resistance according to the first detection voltage, a preset first resistance parameter group corresponding to the first voltage detection module, the first battery voltage, a preset second resistance parameter group corresponding to the battery voltage detection module, and a preset second discharge resistance parameter corresponding to the second discharge module;

[0024] The control processing module controls the switching module to switch to the second state, obtains the second detection voltage of the second voltage detection module and the second battery voltage of the battery voltage detection module, and establishes a second equation about the positive electrode insulation resistance and the negative electrode insulation resistance according to the second detection voltage, the preset second resistance parameter group, the preset third resistance parameter group corresponding to the second voltage detection module, and the preset first discharge resistance parameter corresponding to the first discharge module;

[0025] The control processing module solves the first equation and the second equation to obtain a positive electrode insulation resistance value and a negative electrode insulation resistance value.

[0026] A battery insulation resistance rapid measurement circuit, device and measurement method provided by the present invention have at least the following beneficial effects: the state of the switching module is controlled by the control processing module, in the first state, the second discharge module is turned on, allowing the positive electrode equivalent capacitance of the battery positive electrode to the ground to discharge the stored energy to quickly reach a steady state, and the control processing module constructs a first equation according to the first voltage detection module detecting the first detection voltage of the battery negative electrode and the battery voltage detection module detecting the first battery voltage; in the second state, the first discharge module is turned on, allowing the negative electrode equivalent capacitance of the battery negative electrode to the ground to discharge the stored energy to quickly reach a steady state, and the control processing module constructs a second equation according to the second voltage detection module detecting the second detection voltage of the battery positive electrode and the battery voltage detection module detecting the second battery voltage, and the first equation and the second equation are combined to solve the positive electrode insulation resistance value and the negative electrode insulation resistance value. In this way, the time taken for the equivalent capacitance to reach a steady state is shortened through the first discharge module and the second discharge module, thereby achieving the purpose of fast measurement. At the same time, when obtaining the first detection voltage and the second detection voltage, the first battery voltage and the second battery voltage are obtained respectively, that is, the influence of battery voltage fluctuations is considered, and the positive electrode insulation resistance value and the negative electrode insulation resistance value are obtained by solving the equation based on this, which can avoid measurement errors caused by battery voltage fluctuations and improve the accuracy of insulation resistance measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The present invention provides a circuit diagram of one embodiment of a battery insulation resistance rapid measurement circuit. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Combine the following Figure 1A battery insulation resistance fast measurement circuit of the present invention is described, comprising:

[0031] A battery voltage detection module, used to connect to the positive and negative electrodes of the battery;

[0032] A first voltage detection module, used to be connected to the negative electrode of the battery and the ground;

[0033] A second voltage detection module, used to be connected to the positive electrode of the battery and the ground;

[0034] A first discharge module, connected in parallel with the first voltage detection module;

[0035] A second discharge module, connected in parallel with the second voltage detection module;

[0036] a switching module connected to the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module;

[0037] a control processing module, connected to the battery voltage detection module, the first voltage detection module, the second voltage detection module and the switching module respectively;

[0038] The switching module includes a first state and a second state, the first state turns on the first voltage detection module and the second discharge module and turns off the second voltage detection module and the first discharge module, and the second state turns on the second voltage detection module and the first discharge module and turns off the first voltage detection module and the second discharge module.

[0039] The state of the switching module is controlled by the control processing module. In the first state, the second discharge module is turned on, allowing the positive equivalent capacitance of the battery positive electrode to the ground to discharge the stored energy to quickly reach a steady state. The control processing module constructs a first equation based on the first detection voltage of the battery negative electrode detected by the first voltage detection module and the first battery voltage of the battery detected by the battery voltage detection module; in the second state, the first discharge module is turned on, allowing the negative equivalent capacitance of the battery negative electrode to the ground to discharge the stored energy to quickly reach a steady state. The control processing module constructs a second equation based on the second detection voltage of the battery positive electrode detected by the second voltage detection module and the second battery voltage of the battery detected by the battery voltage detection module. The first equation and the second equation can be solved to obtain the positive electrode insulation resistance value and the negative electrode insulation resistance value. In this way, the time taken for the equivalent capacitance to reach a steady state is shortened through the first discharge module and the second discharge module, thereby achieving the purpose of fast measurement. At the same time, when obtaining the first detection voltage and the second detection voltage, the first battery voltage and the second battery voltage are obtained respectively, that is, the influence of battery voltage fluctuations is considered, and the positive electrode insulation resistance value and the negative electrode insulation resistance value are obtained by solving the equation based on this, which can avoid measurement errors caused by battery voltage fluctuations and improve the accuracy of insulation resistance measurement.

[0040] refer to Figure 1 The positive and negative electrodes of the battery have positive electrode insulation resistance R p And the positive equivalent capacitance C in parallel p , Negative insulation resistance R n And the negative electrode equivalent capacitance C in parallel n , due to the positive insulation resistance R p Resistance value, negative insulation resistance R n The resistance value is relatively large, and the positive equivalent capacitance C p , Negative electrode equivalent capacitance C n The rate of discharging stored energy is relatively slow, and by providing a branch for discharging stored energy through the second discharge module and the first discharge module, the rate of discharging stored energy can be increased, thereby shortening the time taken for the equivalent capacitor to reach a steady state.

[0041] The insulation resistance measurement involves two unknown quantities, the positive electrode insulation resistance value and the negative electrode insulation resistance value, which require two equations to be solved. The first equation and the second equation are established according to the first state and the second state of the switching module, and then the positive electrode insulation resistance value and the negative electrode insulation resistance value are obtained by simultaneous solution. When switching between the first state and the second state, considering that the battery voltage may fluctuate, the first equation is constructed based on the first detection voltage and the first battery voltage obtained at the same time, and the second equation is constructed based on the second detection voltage and the second battery voltage obtained at the same time, which can avoid the influence caused by voltage fluctuations and make the final positive electrode insulation resistance value and negative electrode insulation resistance value more accurate.

[0042] It can be understood that, in addition to the first state and the second state, the switching module may also include a stop measurement state, that is, the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module are all disconnected.

[0043] In some embodiments of the present invention, the control processing module may include implementation methods of devices such as a single-chip microcomputer and an embedded chip.

[0044] refer to Figure 1 In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the switching module includes a first switch element 110, a second switch element 120, a third switch element 130 and a fourth switch element 140, the first switch element 110 is connected to the first voltage detection module, the second switch element 120 is connected to the second voltage detection module, the third switch element 130 is connected to the first discharge module, and the fourth switch element 140 is connected to the second discharge module, the control processing module is connected to the controlled end of the first switch element 110, the controlled end of the second switch element 120, the controlled end of the third switch element 130 and the controlled end of the fourth switch element 140, and the control processing module controls the first switch element 110 and the fourth switch element 140 to close and the second switch element 120 and the third switch element 130 to open, or controls the second switch element 120 and the third switch element 130 to close and the first switch element 110 and the fourth switch element 140 to open.

[0045] In the first state, the first switch 110 and the fourth switch 140 are closed and the second switch 120 and the third switch 130 are disconnected, so that the negative electrode of the battery is connected to the first voltage detection module and disconnected from the first discharge module, and the positive electrode of the battery is connected to the second discharge module and disconnected from the second detection module; in the second state, the second switch 120 and the third switch 130 are closed and the first switch 110 and the fourth switch 140 are disconnected, so that the positive electrode of the battery is connected to the second voltage detection module and disconnected from the second discharge module, and the negative electrode of the battery is connected to the first discharge module and disconnected from the first voltage detection module. In this way, the state of the first switch 110 and the fourth switch 140 are synchronized, the state of the second switch 120 and the third switch 130 are synchronized, and the two groups of states are mutually exclusive, so as to realize the switching detection state.

[0046] The first switch element 110 , the second switch element 120 , the third switch element 130 , and the fourth switch element 140 may be devices capable of realizing a switching function, such as a photocoupler and a field effect transistor.

[0047] It can be understood that, in addition to the first state and the second state, a stop measurement state may also be included, in which the first switch element 110 , the second switch element 120 , the third switch element 130 and the fourth switch element 140 are all disconnected.

[0048] refer to Figure 1 In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the first voltage detection module includes a first voltage-dividing resistor 210, a second voltage-dividing resistor 220 and a first voltage detection element, one end of the first voltage-dividing resistor 210 is used to be connected to the negative electrode of the battery, the other end of the first voltage-dividing resistor 210 is connected to one end of the second voltage-dividing resistor 220 through the first switch element 110, the other end of the second voltage-dividing resistor 220 is grounded, the first voltage detection element is connected to the first voltage-dividing resistor 210 or the second voltage-dividing resistor 220, and the control processing module is connected to the first voltage detection element.

[0049] In the first state, the first switch 110 is closed, the negative pole of the battery is grounded through the first voltage-dividing resistor 210 and the second voltage-dividing resistor 220 to form a discharge branch, and the first voltage detection element detects the voltage of the first voltage-dividing resistor 210 or the second voltage-dividing resistor 220 as the first detection voltage value. Combined with the first resistance value of the first voltage-dividing resistor 210 and the second resistance value of the second voltage-dividing resistor 220, the state of voltage and current can be characterized, which is convenient for the subsequent establishment of the first equation.

[0050] The first voltage detection component can be an implementation method including a proportional step-down circuit, which reduces the voltage according to a set ratio and inputs it to the terminal of the control processing module to achieve the effect of voltage detection; it can also be an implementation method including devices such as a step-down resistor and a voltage transformer.

[0051] In some embodiments of the present invention, the first switch element 110 may be connected in series between the first voltage-dividing resistor 210 and the second voltage-dividing resistor 220 , or between the first voltage-dividing resistor 210 and the negative electrode of the battery or between the second voltage-dividing resistor 220 and ground.

[0052] The first resistance value of the first voltage-dividing resistor 210 and the second resistance value of the second voltage-dividing resistor 220 can be stored in the control processing module as a preset first resistance parameter group to facilitate the control processing module to subsequently solve and calculate the insulation resistance value.

[0053] refer to Figure 1In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the second voltage detection module includes a third voltage-dividing resistor 310, a fourth voltage-dividing resistor 320 and a second voltage detection element, one end of the third voltage-dividing resistor 310 is used to be connected to the positive electrode of the battery, the other end of the third voltage-dividing resistor 310 is connected to one end of the fourth voltage-dividing resistor 320 through the second switch element 120, the other end of the fourth voltage-dividing resistor 320 is grounded, the second voltage detection element is connected to the third voltage-dividing resistor 310 or the fourth voltage-dividing resistor 320, and the control processing module is connected to the second voltage detection element.

[0054] In the second state, the second switch 120 is closed, the positive pole of the battery is grounded via the third voltage-dividing resistor 310 and the fourth voltage-dividing resistor 320 to form a discharge branch, and the second detection component detects the voltage of the third voltage-dividing resistor 310 or the fourth voltage-dividing resistor 320 as the second detection voltage value, which, combined with the third resistance value of the third voltage-dividing resistor 310 and the fourth resistance value of the fourth voltage-dividing resistor 320, can characterize the state of voltage and current, facilitating the subsequent establishment of the second equation.

[0055] The second voltage detection component can be an implementation method including a proportional step-down circuit, which reduces the voltage according to a set ratio and inputs it to the terminal of the control processing module to achieve the effect of voltage detection; it can also be an implementation method including devices such as a step-down resistor and a voltage transformer.

[0056] In some embodiments of the present invention, the second switch 120 may be connected in series between the third voltage-dividing resistor 310 and the fourth voltage-dividing resistor 320 , or between the third voltage-dividing resistor 310 and the positive electrode of the battery or between the fourth voltage-dividing resistor 320 and ground.

[0057] The third resistance value of the third voltage-dividing resistor 310 and the fourth resistance value of the fourth voltage-dividing resistor 320 can be stored in the control processing module as a preset second resistance parameter group to facilitate the control processing module to subsequently solve and calculate the insulation resistance value.

[0058] In some embodiments of the present invention, the first voltage detection module and the second detection module may include, in addition to the implementation of the voltage divider circuit, other balanced bridges, unbalanced bridges and other circuits for detecting resistance values.

[0059] refer to Figure 1 In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the first discharge module includes a first discharge resistor 410, one end of the first discharge resistor 410 is connected to the negative electrode of the battery through the third switch 130, and the other end of the first discharge resistor 410 is grounded.

[0060] In the second state, the third switch is closed, so that the first discharge resistor 410 is connected to the negative electrode of the battery. At the same time, the negative electrode equivalent capacitance of the negative electrode of the battery to the ground is equivalent to being connected in parallel with the negative electrode insulation resistance and the first discharge resistor 410 respectively. Compared with being connected in parallel with the negative electrode insulation resistance only, the first discharge resistor 410 can provide a low-resistance discharge branch, so that the negative electrode equivalent capacitance can quickly discharge the stored energy through the first discharge resistor 410, thereby shortening the time for the negative electrode equivalent capacitance to reach a steady state.

[0061] refer to Figure 1 In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the second discharge module includes a second discharge resistor 420, one end of the second discharge resistor 420 is connected to the positive electrode of the battery through the fourth switch 140, and the other end of the second discharge resistor 420 is grounded.

[0062] In the first state, the fourth switch is closed, so that the second discharge resistor 420 is connected to the positive electrode of the battery. At the same time, the positive electrode equivalent capacitance of the battery positive electrode to the ground is equivalent to being connected in parallel with the positive electrode insulation resistance and the second discharge resistor 420 respectively. Compared with being connected in parallel only with the positive electrode insulation resistance, the second discharge resistor 420 can provide a low-resistance discharge branch, so that the positive electrode equivalent capacitance can quickly discharge the stored energy through the second discharge resistor 420, thereby shortening the time for the positive electrode equivalent capacitance to reach a steady state.

[0063] From the perspective of equivalent resistance after parallel connection, the resistance values ​​of the negative electrode insulation resistance and the positive electrode insulation resistance are relatively large. After the first discharge resistor 410 and the second discharge resistor 420 are connected in parallel, the equivalent resistance value of the whole parallel connection is smaller than the resistance value of the first discharge resistor 410 and the second discharge resistor 420. Therefore, the discharge equivalent resistance value corresponding to the negative electrode equivalent capacitance and the positive electrode equivalent capacitance becomes smaller, which reduces the time consumption for the discharge energy storage to reach a steady state. At the same time, because the overall equivalent resistance value is smaller than the resistance value of the first discharge resistor 410 and the second discharge resistor 420, that is, the overall equivalent resistance value is determined to be within a certain range, and the upper limit time to reach a steady state can be grasped.

[0064] The first discharge module and the second discharge module may also be implemented as a discharge circuit including a plurality of resistors connected in parallel.

[0065] refer to Figure 1In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the battery voltage detection module includes a fifth voltage-dividing resistor 510, a sixth voltage-dividing resistor 520 and a third voltage detection component, one end of the fifth voltage-dividing resistor 510 is connected to the negative electrode of the battery, the other end of the fifth voltage-dividing resistor 510 is connected to one end of the sixth voltage-dividing resistor 520, one end of the sixth voltage-dividing resistor 520 is connected to the positive electrode of the battery, the third voltage detection component is connected to the fifth voltage-dividing resistor 510 or the sixth voltage-dividing resistor 520, and the control processing module is connected to the third voltage detection component.

[0066] The fifth voltage-dividing resistor 510 and the sixth voltage-dividing resistor 520 are connected in series and then connected in parallel with the battery. The voltage of the fifth voltage-dividing resistor 510 or the sixth voltage-dividing resistor 520 is detected by the third voltage detection component. The voltage of the battery can be calculated by combining the fifth resistance value of the fifth voltage-dividing resistor 510 and the sixth resistance value of the sixth resistor.

[0067] In some embodiments of the present invention, the third voltage detection component may be an implementation method including a proportional step-down circuit, which reduces the voltage according to a set ratio and inputs it to the terminal of the control processing module to achieve the effect of voltage detection; it may also be an implementation method including devices such as a step-down resistor and a voltage transformer.

[0068] refer to Figure 1 In some embodiments of a battery insulation resistance rapid measurement circuit of the present invention, a grounding switch 600 is further included, and the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module are all grounded through the grounding switch 600, and the control processing module is connected to the controlled end of the grounding switch 600.

[0069] By providing the grounding switch 600, the grounding state of the entire detection circuit can be controlled, making the control more convenient and improving the reliability of the measurement.

[0070] In some embodiments of the present invention, the grounding switch 600 can be an electric switch, such as a relay or other device; the grounding switch 600 can also be a mechanical switch, which switches its state by manual opening and closing. In the embodiment of the in-place mechanical switch, the control processing module may not be connected to the mechanical switch.

[0071] The ground in the circuit may specifically be the frame of an electric car. The insulation resistance represents the insulation performance between the battery and the frame, which can reflect the safety of the car.

[0072] refer to Figure 1 In some embodiments of a battery insulation resistance fast measurement circuit of the present invention, the first equation is:

[0073]

[0074] The second equation is:

[0075]

[0076] Among them, R n1 is the first resistance value of the first voltage-dividing resistor 210; R n2 is the second resistance value of the second voltage-dividing resistor 220; V n is the voltage of the second voltage-dividing resistor 220; U1 is the first battery voltage; R n is the negative electrode insulation resistance; R p is the positive electrode insulation resistance; R p3 is the resistance value of the second discharge resistor 420; R p1 is the third resistance value of the third voltage-dividing resistor 310; R p2 is the fourth resistance value of the fourth voltage-dividing resistor 320; V p is the voltage of the fourth voltage-dividing resistor 320; U2 is the second battery voltage; R n3 is the resistance value of the first discharge resistor 410; “||” is the resistor parallel calculation symbol, and the specific calculation method is:

[0077] U1 and U2 can be based on the resistance value R of the fifth voltage dividing resistor 510. bat1 The resistance value R of the sixth voltage-dividing resistor 520 is bat2 , combined with the voltage V detected by the third voltage detection element bat Calculate and obtain, the specific calculation formula is:

[0078]

[0079]

[0080] Among them, V bat1 is the voltage of the sixth voltage-dividing resistor 520 in the first state; V bat2 is the voltage of the sixth voltage-dividing resistor 520 in the second state.

[0081] By combining the first and second equations, we can solve the negative electrode insulation resistance R n Insulation resistance R p The specific value of insulation resistance can be measured.

[0082] The present invention also provides a measuring device, comprising the above-mentioned battery insulation resistance fast measuring circuit.

[0083] The measuring device can be arranged on the electric vehicle, and the switching module is controlled by the periodic control processing module to switch the first state and the second state, and then the positive electrode insulation resistance value and the negative electrode insulation resistance value are obtained regularly, so as to achieve the effect of monitoring whether the insulation resistance is abnormal. When the insulation resistance value is less than the preset lower limit value, the control processing module controls the warning module to work and give a warning, so as to improve safety in case of faults.

[0084] The measuring device can also be a device independent of the electric vehicle, used to measure the insulation resistance of the battery in the electric vehicle during maintenance and inspection of the electric vehicle. When the insulation resistance is less than a preset lower limit threshold, the control processing module controls the warning module to work and issue a warning, so as to facilitate the timely detection of faults and improve safety.

[0085] The measuring device of the present invention can correspond to and refer to the above-mentioned battery insulation resistance rapid measurement circuit, and will not be described in detail.

[0086] The present invention also provides a measurement method, which is applied to the above-mentioned battery insulation resistance fast measurement circuit or the above-mentioned measurement device, comprising:

[0087] The control processing module controls the switching module to switch to a first state, obtains a first detection voltage of the first voltage detection module and a first battery voltage of the battery voltage detection module, and establishes a first equation about the positive electrode insulation resistance and the negative electrode insulation resistance according to the first detection voltage, a preset first resistance parameter group corresponding to the first voltage detection module, the first battery voltage, a preset second resistance parameter group corresponding to the battery voltage detection module, and a preset second discharge resistance parameter corresponding to the second discharge module;

[0088] The control processing module controls the switching module to switch to the second state, obtains the second detection voltage of the second voltage detection module and the second battery voltage of the battery voltage detection module, and establishes a second equation about the positive electrode insulation resistance and the negative electrode insulation resistance according to the second detection voltage, the preset second resistance parameter group, the preset third resistance parameter group corresponding to the second voltage detection module, and the preset first discharge resistance parameter corresponding to the first discharge module;

[0089] The control processing module solves the first equation and the second equation to obtain a positive electrode insulation resistance value and a negative electrode insulation resistance value.

[0090] refer to Figure 1, the control processing module controls the switching module to switch to the first state, specifically, controls the first switch 110 (Sn1) and the fourth switch 140 (Sp2) to close and the second switch 120 (Sp1) and the third switch 130 (Sn2) to open, and waits for the preset first time. After the preset first time, the second voltage divider resistor 220 (R n2 ) voltage V n As the first detection voltage and obtain the sixth voltage dividing resistor 520 (R bat2 ) voltage V bat1 Calculate the first battery voltage U1, and then combine the preset first resistance parameter group (including the first resistance value R of the first voltage dividing resistor 210) n1 The second resistance value R of the second voltage dividing resistor 220 n2 ), preset a second resistance parameter group (including the fifth resistance value R of the fifth voltage-dividing resistor 510 bat1 The sixth resistance value R of the sixth voltage dividing resistor 520 bat2 ) and preset parameters of the second discharge resistor 420 (including the resistance value R of the second discharge resistor 420 p3 ), construct the first equation.

[0091] The control processing module controls the control switching module to switch to the second state, specifically controlling the second switch 120 (Sp1) and the third switch 130 (Sn2) to close and the first switch 110 (Sn1) and the fourth switch 140 (Sp2) to disconnect, and wait for the preset second time. After the preset second time, the fourth voltage divider resistor 320 (R p2 ) voltage V p As the second detection voltage and obtaining the sixth voltage dividing resistor 520 (R bat2 ) voltage V bat2 The second battery voltage U2 is calculated, and then combined with the preset third resistance parameter group (including the third resistance value R of the third voltage dividing resistor 310) p1 The fourth resistance value R of the fourth voltage dividing resistor 320 p2 ), preset a second resistance parameter group (including the fifth resistance value R of the fifth voltage-dividing resistor 510 bat1 The sixth resistance value R of the sixth voltage dividing resistor 520 bat2 ) and preset parameters of the first discharge resistor 410 (including the resistance value R of the first discharge resistor 410 n3 ), construct the second equation.

[0092] Solve the first and second equations together to obtain the positive electrode insulation resistance value R p Insulation resistance value R n. Insulation resistance measurement is achieved in this way, and during the measurement process, the negative electrode equivalent capacitance of the battery negative electrode to the ground and the positive electrode equivalent capacitance of the battery positive electrode to the ground can quickly reach a steady state through the first discharge module and the second discharge module, which is conducive to shortening the measurement time. At the same time, in the first state and the second state, the detection voltage and the battery voltage are obtained synchronously, that is, the first battery voltage U1 and the second battery voltage U2 are obtained respectively, which can avoid the measurement error caused by battery voltage fluctuations and improve the accuracy of insulation resistance measurement.

[0093] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0094] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. 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 this specification, 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. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery insulation resistance fast measurement circuit, characterized in that: include: A battery voltage detection module, used to connect to the positive and negative electrodes of the battery; A first voltage detection module, used to be connected to the negative electrode of the battery and the ground; A second voltage detection module, used to be connected to the positive electrode of the battery and the ground; A first discharge module, connected in parallel with the first voltage detection module; A second discharge module, connected in parallel with the second voltage detection module; a switching module connected to the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module, the switching module including a first state and a second state; a control processing module, connected to the battery voltage detection module, the first voltage detection module, the second voltage detection module and the switching module respectively; The switching module comprises a first switch element (110), a second switch element (120), a third switch element (130) and a fourth switch element (140); the first switch element (110) is connected to the first voltage detection module, the second switch element (120) is connected to the second voltage detection module, the third switch element (130) is connected to the first discharge module, the fourth switch element (140) is connected to the second discharge module, and the control processing module is connected to a controlled end of the first switch element (110), a controlled end of the second switch element (120), a controlled end of the third switch element (130) and a controlled end of the fourth switch element (140); In a first state, the control processing module controls the first switch element (110) and the fourth switch element (140) to be closed and the second switch element (120) and the third switch element (130) to be opened, and the control processing module synchronously acquires a first detection voltage of the first voltage detection module and a first battery voltage of the battery voltage detection module; In the second state, the control processing module controls the second switch component (120) and the third switch component (130) to be closed and the first switch component (110) and the fourth switch component (140) to be opened, and the control processing module synchronously obtains the second detection voltage of the second voltage detection module and the second battery voltage of the battery voltage detection module; wherein the first detection voltage, the first battery voltage, the second detection voltage and the second battery voltage are used to construct equations to solve simultaneously to obtain the positive electrode insulation resistance value and the negative electrode insulation resistance value.

2. A battery insulation resistance fast measurement circuit according to claim 1, characterized in that: The first voltage detection module comprises a first voltage-dividing resistor (210), a second voltage-dividing resistor (220) and a first voltage detection element, one end of the first voltage-dividing resistor (210) is used to be connected to the negative electrode of the battery, the other end of the first voltage-dividing resistor (210) is connected to one end of the second voltage-dividing resistor (220) through the first switch element (110), the other end of the second voltage-dividing resistor (220) is grounded, the first voltage detection element is connected to the first voltage-dividing resistor (210) or the second voltage-dividing resistor (220), and the control processing module is connected to the first voltage detection element.

3. A battery insulation resistance fast measurement circuit according to claim 1, characterized in that: The second voltage detection module comprises a third voltage-dividing resistor (310), a fourth voltage-dividing resistor (320) and a second voltage detection element, one end of the third voltage-dividing resistor (310) is used to be connected to the positive electrode of the battery, the other end of the third voltage-dividing resistor (310) is connected to one end of the fourth voltage-dividing resistor (320) through the second switch element (120), the other end of the fourth voltage-dividing resistor (320) is grounded, the second voltage detection element is connected to the third voltage-dividing resistor (310) or the fourth voltage-dividing resistor (320), and the control processing module is connected to the second voltage detection element.

4. A battery insulation resistance fast measurement circuit according to claim 1, characterized in that: The first discharge module comprises a first discharge resistor (410), one end of the first discharge resistor (410) is connected to the negative electrode of the battery through the third switch (130), and the other end of the first discharge resistor (410) is grounded.

5. A battery insulation resistance fast measurement circuit according to claim 1, characterized in that: The second discharge module comprises a second discharge resistor (420), one end of the second discharge resistor (420) is connected to the positive electrode of the battery through the fourth switch (140), and the other end of the second discharge resistor (420) is grounded.

6. A battery insulation resistance fast measurement circuit according to claim 1, characterized in that: The battery voltage detection module comprises a fifth voltage-dividing resistor (510), a sixth voltage-dividing resistor (520) and a third voltage detection component, one end of the fifth voltage-dividing resistor (510) is connected to the negative electrode of the battery, the other end of the fifth voltage-dividing resistor (510) is connected to one end of the sixth voltage-dividing resistor (520), one end of the sixth voltage-dividing resistor (520) is connected to the positive electrode of the battery, the third voltage detection component is connected to the fifth voltage-dividing resistor (510) or the sixth voltage-dividing resistor (520), and the control processing module is connected to the third voltage detection component.

7. A battery insulation resistance fast measurement circuit according to any one of claims 1 to 6, characterized in that: It also includes a grounding switch (600), through which the first voltage detection module, the second voltage detection module, the first discharge module and the second discharge module are all grounded, and the control processing module is connected to the controlled end of the grounding switch (600).

8. A measuring device, characterized in that It comprises a battery insulation resistance rapid measurement circuit as claimed in any one of claims 1 to 7, and also comprises a warning module, and the control processing module is connected to the warning module.

9. A measuring method, characterized in that A battery insulation resistance fast measurement circuit as claimed in any one of claims 1 to 7 or a measurement device as claimed in claim 8, comprising: The control processing module controls the switching module to switch to a first state, obtains a first detection voltage of the first voltage detection module and a first battery voltage of the battery voltage detection module, and establishes a first equation about the positive electrode insulation resistance and the negative electrode insulation resistance according to the first detection voltage, a preset first resistance parameter group corresponding to the first voltage detection module, the first battery voltage, a preset second resistance parameter group corresponding to the battery voltage detection module, and a preset second discharge resistance parameter corresponding to the second discharge module; The control processing module controls the switching module to switch to the second state, obtains the second detection voltage of the second voltage detection module and the second battery voltage of the battery voltage detection module, and establishes a second equation about the positive electrode insulation resistance and the negative electrode insulation resistance according to the second detection voltage, the preset second resistance parameter group, the preset third resistance parameter group corresponding to the second voltage detection module, and the preset first discharge resistance parameter corresponding to the first discharge module; The control processing module solves the first equation and the second equation to obtain a positive electrode insulation resistance value and a negative electrode insulation resistance value.

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