CN114563674B - A kind of insulation detection device and method applied to energy storage system - Google Patents

Abstract

The invention relates to an insulation detection device and a method applied to an energy storage system. The device comprises an energy storage module, a Y capacitor processing circuit, a battery management module and a power supply module, wherein a sequential electric power supply is arranged between the positive input and the negative input of the power module. A first capacitor branch and a second capacitor branch with the same capacitance value are connected, the battery management module is provided with a first resistance branch and a second resistance branch with the same resistance value that are electrically connected in sequence, and the first resistor The electrical connection point between the branch circuit and the second resistance branch circuit is electrically connected to one end of the Y capacitor processing circuit, and the other end of the Y capacitor processing circuit is electrically connected to the casing of the energy storage module. The Y capacitor processing circuit is used to eliminate the input current in the casing of the energy storage module during insulation detection. By setting the Y capacitor processing circuit, the current generated at the casing caused by the charging and discharging of the Y capacitor in the power module can be offset, and the accurate insulation detection of the energy storage module can be realized.

Description

A kind of insulation detection device and method applied to energy storage system

technical field

The invention relates to the technical field of insulation detection of energy storage modules, in particular to an insulation detection device and method applied to an energy storage system.

Background technique

Energy storage, as an emerging industry, is on the rise. At present, domestic energy storage technology is developing from small-scale to large-scale applications. There are battery leakage in the application of energy storage modules, aging of wiring harnesses, broken skin, and temperature sensor NTC broken skin. Problems such as insulation decline, as the resistance value continues to decline, will lead to a direct short circuit of the battery and cause a fire. Therefore, it is necessary to perform insulation testing on the energy storage module.

The battery insulation detection methods include unbalanced bridge and pulse injection. Pulse injection will affect the stability of other products in the system. Now more than 95% of the energy storage insulation detection adopts the unbalanced bridge principle. When the energy storage module is connected to the power supply (such as PCS inverter) When charging and discharging, there is a Y capacitor in the power module, and the charging and discharging current of the Y capacitor will affect the insulation resistance sampling. The insulation detection solution of the existing energy storage module is that the system is connected to the power module, and the single insulation acquisition period is lengthened, waiting for the capacitor After the charging and discharging process is completed, the insulation value of the system is collected again. The single insulation collection time is 5~10min. With the application of the 1500V energy storage system, the resistance of the internal voltage divider increases, the insulation collection period will become slower, and the accuracy will become lower. The waiting time will cause a delay in system alarms and reduce security.

Therefore, it is necessary to provide an insulation detection device that can eliminate the influence of Y capacitance on insulation detection and can accurately perform insulation detection to solve the above technical problems.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides an insulation detection device applied to an energy storage system. The technical problems of long acquisition period and low detection precision in the prior art for insulation detection of the energy storage system by using the unbalanced bridge principle are solved.

The technical effect of the present invention is achieved by the following:

An insulation detection device applied to an energy storage system, comprising an energy storage module, a Y capacitor processing circuit, a battery management module and a power supply module, wherein the energy storage module, the battery management module and the power supply module are connected in sequence, and the A first capacitor branch and a second capacitor branch with the same capacitance value are electrically connected in sequence between the positive input and the negative input of the power module, and the electrical connection between the first capacitor branch and the second capacitor branch is The connection point is electrically connected to the casing of the energy storage module, the first capacitor branch and the second capacitor branch are both composed of at least one Y capacitor unit, and the battery management module is provided with resistors that are electrically connected in sequence The first resistance branch and the second resistance branch with the same value, the first resistance branch and the second resistance branch are both composed of at least one resistance unit, and the first resistance branch and the second resistance branch are composed of at least one resistance unit. The electrical connection point between the resistance branches is electrically connected to one end of the Y capacitor processing circuit, the other end of the Y capacitor processing circuit is electrically connected to the casing of the energy storage module, and the Y capacitor processing circuit is used for When performing insulation detection on the energy storage module, the input current in the casing of the energy storage module is eliminated to accurately measure the insulation resistance value of the energy storage module. By setting the Y capacitor processing circuit, the current generated at the casing caused by the charging and discharging of the Y capacitor in the power module can be offset, and the accurate insulation detection of the energy storage module can be realized, which solves the problem of using the unbalanced bridge principle in the prior art. The system has long acquisition period for insulation detection and low detection accuracy.

Further, the Y capacitor processing circuit includes a first switch and a first diode, the anode of the first diode is electrically connected to the casing of the energy storage module through the first switch, and the first diode is electrically connected to the casing of the energy storage module. An electrical connection point between a resistance branch and the second resistance branch is electrically connected to the negative electrode of the first diode. By arranging the first switch and the first diode in the Y capacitor processing circuit, the first diode can block the input current of the casing by closing the first switch when measuring the resistance value of the casing facing the casing. Therefore, it eliminates the problem that the resistance value of the opposite case detected by the insulation is too small due to the large current formed by the charging of the Y capacitor.

Further, the Y capacitor processing circuit further includes a second switch and a second diode, the cathode of the second diode is electrically connected to the casing of the energy storage module through the second switch, and the The electrical connection point between the first resistance branch and the second resistance branch is electrically connected to the anode of the second diode. By arranging the second switch and the second diode in the Y capacitor processing circuit, the current flowing into the chassis and the Y capacitor of the second diode can be realized by closing the second switch when measuring the negative resistance of the chassis to the chassis. The neutralization of the current input to the casing by the discharge, thereby eliminating the problem that the resistance value of the negative pair of the casing detected by the insulation is too small due to the current input to the casing caused by the discharge of the Y capacitor.

Further, the first resistance branch further includes a third switch, and the third switch is connected in series with the resistance unit in the first resistance branch.

Further, the second resistance branch further includes a fourth switch, and the fourth switch is connected in series with the resistance unit in the second resistance branch.

Further, the first resistance branch is provided with a first voltage detection point, and the first voltage detection point is electrically connected to the current input end of one of the resistance units in the first resistance branch.

Further, the second resistance branch is provided with a second voltage detection point, and the second voltage detection point is electrically connected to the current input end of one of the resistance units in the second resistance branch.

Further, it also includes a total positive relay and a total negative relay, the positive input of the power module is electrically connected to one end of the battery management module through the total positive relay, and the negative input of the power module is connected through the total negative relay. is electrically connected to the other end of the battery management module.

In addition, an insulation detection method applied to an energy storage system is also provided. The method is implemented based on the above-mentioned insulation detection device applied to an energy storage system, including:

When the Y capacitor in the Y capacitor unit is charged, control the first switch to close and obtain the voltage of the first voltage detection point at the current moment;

Based on the first total circuit current and according to the voltage of the first voltage detection point, the resistance value facing the chassis corresponding to the energy storage module is obtained;

When the Y capacitor in the Y capacitor unit is charged, the second switch is controlled to be closed and the voltage of the second voltage detection point at the current moment is obtained;

Based on the second total circuit current, the negative-to-chassis resistance value corresponding to the energy storage module is obtained according to the voltage of the second voltage detection point, so as to complete the insulation detection of the energy storage module.

Further, the controlling and closing of the first switch and the acquisition of the voltage of the first voltage detection point at the current moment include:

controlling the third switch to close and combine to obtain the voltage of the first voltage detection point at the current moment;

Based on the first total circuit current and according to the voltage of the first voltage detection point, the resistance value facing the chassis corresponding to the energy storage module is obtained;

Controlling the fourth switch and combining to obtain the voltage of the second voltage detection point at the current moment;

Based on the second total circuit current, obtain the negative-to-chassis resistance value corresponding to the energy storage module according to the voltage of the second voltage detection point to complete the insulation detection of the energy storage module;

When the preset time is reached, obtain the voltage of the first voltage detection point at the current moment and the voltage of the second voltage detection point at the current moment, and obtain the storage voltage according to the voltage of the first voltage detection point based on the first bus current. The resistance value facing the casing corresponding to the energy storage module is obtained, and the resistance value facing the casing corresponding to the energy storage module is obtained based on the first total circuit current according to the voltage of the first voltage detection point;

The first change value is obtained according to the corresponding positive-to-chassis resistance value when the third switch is closed and the positive-to-chassis resistance value corresponding to the preset time, and the corresponding negative-to-chassis resistance value when the fourth switch is closed and reaches The second change value is obtained from the negative pair of chassis resistance value corresponding to the preset time;

If both the first change value and the second change value are smaller than the preset value, do not control the first switch to close and obtain the voltage of the first voltage detection point at the current moment;

Otherwise, the control of the first switch is executed and the voltage of the first voltage detection point at the current moment is obtained. Before the first switch and the second switch are closed, the detection of the positive resistance value of the casing and the negative resistance value of the casing can be directly completed according to the set time interval, so that it can be judged whether the Y capacitor has an influence on the insulation detection. In different situations, the Y capacitor processing circuit can be adaptively controlled to work or not to achieve accurate insulation detection of the energy storage system.

As mentioned above, the present invention has the following beneficial effects:

1) By setting the Y capacitor processing circuit, the current generated at the casing caused by the charging and discharging of the Y capacitor in the power module can be offset, and the accurate insulation detection of the energy storage module can be realized, which solves the problem of using the unbalanced bridge principle in the prior art. The technical problems of long acquisition period and low detection accuracy of energy storage system for insulation detection.

2) By setting the first switch and the first diode in the Y capacitor processing circuit, the input current of the first diode to the casing is realized by closing the first switch when measuring the resistance of the casing facing the casing. Blocking is performed, thereby eliminating the problem that the resistance value of the opposite case detected by the insulation is too small due to the large current formed by the charging of the Y capacitor.

3) By setting the second switch and the second diode in the Y capacitor processing circuit, the current and The neutralization of the current input to the chassis by the discharge of the Y capacitor, thus eliminating the problem that the resistance of the negative pair of the chassis detected by the insulation is too small due to the current input to the chassis caused by the discharge of the Y capacitor.

4) Before the first switch and the second switch are closed, by directly completing the detection of the positive resistance value of the chassis and the negative resistance value of the chassis according to the set time interval, it can be judged whether the Y capacitor has an influence on the insulation detection, thereby The Y capacitor processing circuit can be adaptively controlled to work or not work under different circumstances to achieve accurate insulation detection of the energy storage system.

Description of drawings

In order to illustrate the technical solutions of the present invention more clearly, the following will briefly introduce the accompanying drawings that are required to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a schematic circuit diagram of an insulation detection device applied to an energy storage system provided by an embodiment of the present specification;

FIG. 2 is a flowchart of an insulation detection method applied to an energy storage system according to an embodiment of the present specification.

Among them, the reference signs in the figure correspond to:

Energy storage module 1, Y capacitor processing circuit 2, first switch 21, first diode 22, second switch 23, second diode 24, battery management module 3, resistor 31, power module 4, Y capacitor 41 .

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

Example 1:

As shown in FIG. 1 , the embodiment of this specification provides an insulation detection device applied to an energy storage system. The insulation detection device is used to detect the insulation resistance of the casing of the energy storage system to ensure the stability of the energy storage system. The insulation detection The device includes an energy storage module 1, a Y capacitor processing circuit 2, a battery management module 3 and a power supply module 4. The energy storage module 1, the battery management module 3 and the power supply module 4 are connected in sequence, and the power supply module 4 is provided with a positive input and a negative input. The first capacitor branch and the second capacitor branch with the same capacitance value are electrically connected in sequence, and the electrical connection point between the first capacitor branch and the second capacitor branch is electrically connected to the casing of the energy storage module 1, and the first capacitor branch and the second capacitor branch are electrically connected to the casing. The capacitor branch and the second capacitor branch are both composed of at least one Y capacitor unit. The battery management module 3 is provided with a first resistance branch and a second resistance branch with the same resistance value that are electrically connected in sequence. The first resistance branch and the The second resistance branch is composed of at least one resistance unit, the electrical connection point between the first resistance branch and the second resistance branch is electrically connected to one end of the Y capacitor processing circuit 2, and the other end of the Y capacitor processing circuit 2 is connected to the storage The casing of the energy storage module 1 is electrically connected, and the Y capacitor processing circuit 2 is used to eliminate the input current in the casing of the energy storage module 1 during insulation detection of the energy storage module 1 to accurately measure the insulation resistance value of the energy storage module 1 .

Specifically, the Y capacitor unit may be one Y capacitor, or may be formed by connecting more than one Y capacitors in series, in parallel, or in combination, and the multiple Y capacitors may be the same or different. In this embodiment, the first capacitor branch and the second capacitor branch both include a Y capacitor unit, and the Y capacitor unit is a Y capacitor 41 for description. That is, in FIG. 1 , both C1 and C2 are Y capacitors 41 , the first capacitor branch is C1 , and the second capacitor branch is C2 .

Specifically, the resistance unit may be one resistance, or may be formed by connecting more than one resistance in series or in parallel or in a mixed connection, and the plurality of resistances may be the same or different. In this embodiment, both the first resistance branch and the second resistance branch include two resistance units, and the resistance unit is constituted by one resistance 31 for description. That is, R1, R2, R3, and R4 are all resistors 31. The first resistance branch is formed by R1 and R2 in series, and the second resistance branch is formed by R3 and R4 in series.

Preferably, the Y capacitor processing circuit 2 includes a first switch 21 and a first diode 22, the anode of the first diode 22 is electrically connected to the casing of the energy storage module 1 through the first switch 21, and the first resistance branch , The electrical connection point between the second resistance branches is electrically connected to the negative electrode of the first diode 22 . By arranging the first switch 21 and the first diode 22 in the Y capacitor processing circuit 2, the first diode 22 is connected to the casing by closing the first switch 21 when measuring the resistance of the casing facing the casing. The input current is blocked, thereby eliminating the problem that the Y capacitor 41 is charged to form a large current and the resistance value of the opposite case detected by the insulation is too small.

Preferably, the Y capacitor processing circuit 2 further includes a second switch 23 and a second diode 24, the cathode of the second diode 24 is electrically connected to the casing of the energy storage module 1 through the second switch 23, and the first resistor supports The electrical connection point between the circuit and the second resistance branch is electrically connected to the anode of the second diode 24 . By arranging the second switch 23 and the second diode 24 in the Y capacitor processing circuit 2, the second diode 24 can flow into the casing by closing the second switch 23 when measuring the negative resistance of the casing to the casing The neutralization of the current discharged by the Y capacitor 41 and the current input to the casing by the discharge of the Y capacitor 41 eliminates the problem that the resistance value of the negative pair of the casing detected by the insulation is too small due to the discharge of the Y capacitor 41 entering the casing.

It should be noted that in the current insulation testing methods for energy storage systems, it is common to use the unbalanced bridge principle for testing. When the energy storage module is connected to a power supply (such as a PCS inverter) for charging and discharging, Y The charging and discharging current of capacitors and Y capacitors will affect the sampling of insulation resistance. The single-shot insulation sampling period is lengthened. After the capacitor charging and discharging process is completed, the system insulation value is collected. The single-shot insulation sampling time is 5~10min. With the application of energy storage 1500V system, If the resistance of the internal voltage divider increases, the insulation acquisition cycle will become slower and the accuracy will become lower.

Therefore, by arranging the Y capacitor processing circuit 2, the current generated at the casing caused by the charging and discharging of the Y capacitor 41 in the power module 4 can be offset, so as to realize the accurate insulation detection of the energy storage module 1, and solve the problem of using different methods in the prior art. The balance bridge principle has the technical problems of long acquisition period and low detection accuracy for insulation detection of energy storage systems.

Preferably, the first resistance branch further includes a third switch Q1, and the third switch Q1 is connected in series with the resistance unit in the first resistance branch.

Preferably, the first resistance branch is provided with a first voltage detection point U2, and the first voltage detection point U2 is electrically connected to the current input end of one of the resistance units in the first resistance branch.

Specifically, as shown in FIG. 1, the total current I1 is measured in real time in the circuit, the first voltage detection point U2 is set at R2 close to the positive end of the energy storage module 1, and when the third switch Q1 is closed, the first voltage detection point is obtained by obtaining the first voltage detection point The voltage value of U2, and then according to the resistance value of R2, the current I2 of the branch where R2 is located can be calculated to obtain the voltage at both ends of the first resistance branch formed by the series connection of R1 and R2, that is, the voltage across the two ends of the chassis resistance Rx. Voltage U1, so that the resistance value of the resistance Rx facing the casing is calculated as U1/(I1-I2), the resistance Rx facing the casing can be calculated, and the insulation characteristics of the energy storage module 1 facing forward can be judged.

Preferably, the second resistance branch further includes a fourth switch Q2, and the fourth switch Q2 is connected in series with the resistance unit in the second resistance branch.

Preferably, a second voltage detection point U3 is provided on the second resistance branch, and the second voltage detection point U3 is electrically connected to the current input end of one of the resistance units in the second resistance branch.

Specifically, as shown in FIG. 1, the total current I3 is measured in real time in the circuit, the second voltage detection point U3 is set at R3 close to the negative end of the energy storage module 1, and when the fourth switch Q2 is closed, the second voltage detection point is obtained by obtaining the second voltage detection point The voltage value of U3, and then according to the resistance value of R3, the current I4 of the branch where R3 is located can be calculated, so as to obtain the voltage at both ends of the second resistance branch formed by the series connection of R3 and R4, that is, the negative pair of the two ends of the chassis resistance Rx Voltage U2, and then according to the total resistance value of R3 and R4 to get the voltage U2 across the negative case resistance Rx, so as to calculate the resistance value of the positive case resistance Rx U2/(I3-I4), you can calculate the negative For the chassis resistance Rx, the negative-pair insulation characteristics of the energy storage module 1 are judged.

Preferably, it also includes a total positive relay and a total negative relay, the positive input of the power module 4 is electrically connected to one end of the battery management module 3 through the total positive relay, and the negative input of the power module 4 is connected to the other terminal of the battery management module 3 through the total negative relay. One end is electrically connected.

In the prior art, the Y capacitor processing circuit 2 is not provided, that is, the electrical connection point between the first resistance branch and the second resistance branch is directly electrically connected with the casing of the energy storage module 1, so as to carry out the adjustment of the energy storage module 1. Insulation testing of the enclosure. For the difference between the application and the prior art, the following descriptions are made:

In the prior art, the insulation detection of the casing includes the measurement of the positive resistance value of the casing and the negative resistance value of the casing.

The test process of the resistance value of the case:

The Q1 and Q2 switches are disconnected, the total positive relay is closed, the energy storage module 1 is charging C1 and C2, and C1 and C2 are in the charging state. The current in the circuit continues to drop. At this time, when Q1 is closed, a large current will be formed at the moment of closing Q1, and current will flow into the PE of the casing, so the calculated resistance of the opposite casing will be small, resulting in poor insulation detection. precise.

After closing Q1 and disconnecting the Q2 switch, after a period of time, when the total negative charge is completed, the current of the casing pe gradually decreases and tends to zero. At this time, the current of the casing PE has no effect on the insulation detection, so there is no need to control the Y capacitor processing. Circuit 2 works.

Negative-to-chassis resistance test process:

The Q1 and Q2 switches are disconnected, the total positive relay is closed, the energy storage module 1 is charging C1 and C2, and C1 and C2 are in the charging state. The current in the circuit continues to drop. At this time, when Q2 is closed, a large current will be formed at the moment of closing Q2, and current will flow into the PE of the casing, so the calculated resistance of the negative pair of the casing will be small, resulting in poor insulation detection. precise.

When the total positive charge is completed, the current of the case PE gradually decreases and tends to zero when the total negative discharge is completed. At this time, the current of the case PE has no effect on the insulation detection, so there is no need to control the Y capacitor processing circuit 2 to work.

In this application, the resistance value test process of the casing is as follows:

Close Q1, open Q2, and control the first switch 21 of the Y capacitor processing circuit 2 to close at the same time, so that the first diode 22 connected in series with the first switch 21 blocks the current of the casing PE, thereby eliminating the problem of The influence of the current of the shell PE on the insulation detection.

Negative-to-chassis resistance test process:

Close Q1, open Q2, and control the second switch 23 of the Y capacitor processing circuit 2 to close at the same time, so that the second diode 24 connected to the second switch 23 neutralizes the current of the casing PE, thereby eliminating the problem of The influence of the current of the shell PE on the insulation detection.

As shown in FIG. 2 , an embodiment of the present specification provides an insulation detection method applied to an energy storage system. The method implemented by the insulation detection device applied to an energy storage system in Embodiment 1 includes:

S100: when the Y capacitor in the Y capacitor unit is charged, control the first switch 21 to close and obtain the voltage of the first voltage detection point U2 at the current moment;

S200: based on the first total circuit current and according to the voltage of the first voltage detection point U2, obtain the corresponding resistance value of the opposite casing of the energy storage module 1;

S300: when the Y capacitor in the Y capacitor unit is discharged, control the second switch 23 to close and obtain the voltage of the second voltage detection point U3 at the current moment;

S400: Obtaining the negative-to-chassis resistance value corresponding to the energy storage module 1 according to the voltage of the second voltage detection point U3 based on the second total circuit current to complete the insulation detection of the energy storage module 1.

In a specific implementation manner, in step S100, controlling the first switch 21 to close and obtaining the voltage of the first voltage detection point U2 at the current moment includes:

Control the third switch Q1 to close and obtain the voltage of the first voltage detection point U2 at the current moment;

Based on the first total circuit current and according to the voltage of the first voltage detection point U2, the resistance value facing the casing corresponding to the energy storage module 1 is obtained;

Control the fourth switch Q2 to close and obtain the voltage of the second voltage detection point U3 at the current moment;

Based on the second total circuit current, the negative-to-chassis resistance value corresponding to the energy storage module 1 is obtained according to the voltage of the second voltage detection point U3 to complete the insulation detection of the energy storage module 1;

When the preset time is reached, the voltage of the first voltage detection point U2 at the current moment and the voltage of the second voltage detection point U3 at the current moment are obtained, and the voltage of the first voltage detection point U2 is obtained based on the first bus current and the voltage of the first voltage detection point U2 The resistance value facing the casing corresponding to the energy storage module 1, and the resistance value facing the casing corresponding to the energy storage module 1 is obtained based on the first total circuit current according to the voltage of the first voltage detection point U2;

The first change value is obtained according to the corresponding positive-to-chassis resistance value when the third switch Q1 is closed and the positive-to-chassis resistance value corresponding to the preset time, and the corresponding negative-to-chassis resistance value when the fourth switch Q2 is closed The second change value is obtained from the negative resistance value of the chassis corresponding to the preset time;

If both the first change value and the second change value are smaller than the preset value, then do not control the first switch 21 to close and obtain the voltage of the first voltage detection point U2 at the current moment;

Otherwise, control the first switch 21 to close and obtain the voltage of the first voltage detection point U2 at the current moment.

Wherein, the preset value is set by the person in the art according to the standard of insulation detection.

Specifically, when detecting the resistance value of the positive pair of casings or the resistance value of the negative pair of casings, after a preset time interval, the resistance value of the positive pair of casings or the resistance value of the negative pair of casings is detected again. If the value changes too much, it means that the Y capacitor has an impact on the insulation detection, and the process of controlling the Y capacitor processing circuit is entered, that is, the corresponding first switch 21 or the second switch 23 is closed;

If it is detected in the subsequent sequence that the change of the resistance value tends to remain unchanged, that is, it is less than the preset value, it means that the influence of the Y capacitor has temporarily disappeared, and it is not necessary to control the Y capacitor processing circuit 2 for assistance, and then the resistance value of the opposite case can be completed. and negative detection of the casing resistance, that is, the circuit connection relationship at this time is that the electrical connection point between the first resistance branch and the second resistance branch is directly electrically connected to the casing of the energy storage module 1 .

The detection process is continuous, that is, according to the preset time set by those skilled in the art, the detection is completed every preset time interval, until the detected resistance value no longer changes, or the change is within the preset value range. The detection results at this time are accurate results.

Before the first switch 21 and the second switch 23 are closed, the detection of the positive resistance value of the casing and the negative resistance value of the casing can be directly completed according to the set time interval, so that it can be judged whether the Y capacitor has an influence on the insulation detection. The Y capacitor processing circuit 2 can be adaptively controlled to work or not to work under different circumstances, so as to achieve accurate insulation detection of the energy storage system.

Although the present invention has been described in terms of the preferred embodiments, the present invention is not limited to the embodiments described herein, and various changes and changes can be made without departing from the scope of the present invention.

The above-described embodiments and features of the embodiments herein can be combined with each other without conflict.

The above disclosure is only a preferred embodiment of the present invention, and of course, it cannot limit the scope of the rights of the present invention. Therefore, the equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims (8)

1. An insulation detection device applied to an energy storage system is characterized by comprising an energy storage module (1), a Y capacitance processing circuit (2), a battery management module (3) and a power module (4), wherein the energy storage module (1), the battery management module (3) and the power module (4) are sequentially connected, a first capacitance branch and a second capacitance branch which are sequentially and electrically connected and have the same capacitance value are arranged between the positive input and the negative input of the power module (4), the electrical connection point between the first capacitance branch and the second capacitance branch is electrically connected with a casing of the energy storage module (1), the first capacitance branch and the second capacitance branch are respectively composed of at least one Y capacitance unit, the battery management module (3) is provided with a first resistance branch and a second resistance branch which are sequentially and electrically connected and have the same resistance value, the first resistance branch circuit and the second resistance branch circuit are both composed of at least one resistance unit, an electric connection point between the first resistance branch circuit and the second resistance branch circuit is electrically connected with one end of the Y capacitance processing circuit (2), the other end of the Y capacitance processing circuit (2) is electrically connected with a machine shell of the energy storage module (1), the Y capacitance processing circuit (2) is used for eliminating input current in the machine shell of the energy storage module (1) when the energy storage module (1) is subjected to insulation detection so as to accurately measure the insulation resistance value of the energy storage module (1),

the Y capacitance processing circuit (2) comprises a first switch (21) and a first diode (22), the anode of the first diode (22) is electrically connected with the shell of the energy storage module (1) through the first switch (21), the electric connection point between the first resistance branch and the second resistance branch is electrically connected with the cathode of the first diode (22),

the Y capacitance processing circuit (2) further comprises a second switch (23) and a second diode (24), the cathode of the second diode (24) is electrically connected with the shell of the energy storage module (1) through the second switch (23), and the electrical connection point between the first resistance branch and the second resistance branch is electrically connected with the anode of the second diode (24).

2. The insulation detection device applied to the energy storage system according to claim 1, wherein the first resistive branch further comprises a third switch, and the third switch is connected in series with the resistive unit in the first resistive branch.

3. The insulation detection device applied to the energy storage system according to claim 2, wherein the second resistance branch further comprises a fourth switch, and the fourth switch is connected in series with the resistance unit in the second resistance branch.

4. The insulation detection device as recited in claim 3, wherein the first resistor branch has a first voltage detection point, and the first voltage detection point is electrically connected to a current input terminal of one of the resistor units in the first resistor branch.

5. The insulation detection device as claimed in claim 4, wherein a second voltage detection point is disposed on the second resistor branch, and the second voltage detection point is electrically connected to the current input terminal of one of the resistor units in the second resistor branch.

6. The insulation detection device applied to the energy storage system as recited in claim 1, further comprising a total positive relay and a total negative relay, wherein the positive input of the power supply module (4) is electrically connected with one end of the battery management module (3) through the total positive relay, and the negative input of the power supply module (4) is electrically connected with the other end of the battery management module (3) through the total negative relay.

7. An insulation detection method applied to an energy storage system, the method being implemented based on the insulation detection device applied to an energy storage system according to claim 6, and comprising:

when a Y capacitor in the Y capacitor unit is charged, controlling a first switch (21) to be closed and acquiring the voltage of a first voltage detection point at the current moment;

obtaining a corresponding resistance value of the energy storage module (1) opposite to the case according to the voltage of the first voltage detection point based on the first total path current;

when the Y capacitor in the Y capacitor unit discharges, controlling a second switch (23) to be closed and acquiring the voltage of a second voltage detection point at the current moment;

and obtaining the negative pair of shell resistance values corresponding to the energy storage module (1) according to the voltage of the second voltage detection point based on the second main path current so as to complete the insulation detection of the energy storage module (1).

8. The insulation detection method applied to the energy storage system as recited in claim 7, wherein the controlling the first switch (21) to be closed and acquiring the voltage of the first voltage detection point at the current time is preceded by:

controlling a third switch to be closed and acquiring the voltage of the first voltage detection point at the current moment;

obtaining a corresponding resistance value of the energy storage module (1) opposite to the case according to the voltage of the first voltage detection point based on the first total path current;

controlling the fourth switch to be switched off and acquiring the voltage of the second voltage detection point at the current moment;

obtaining a negative pair case resistance value corresponding to the energy storage module (1) according to the voltage of the second voltage detection point based on the second main path current so as to complete insulation detection of the energy storage module (1);

when the preset time is reached, acquiring the voltage of a first voltage detection point at the current moment and the voltage of a second voltage detection point at the current moment, acquiring a counter case resistance value corresponding to the energy storage module (1) according to the voltage of the first voltage detection point based on a first total path current, and acquiring a counter case resistance value corresponding to the energy storage module (1) according to the voltage of the first voltage detection point based on the first total path current;

obtaining a first change value according to the corresponding positive case resistance value when the third switch is closed and the corresponding positive case resistance value when the preset time is reached, and obtaining a second change value according to the corresponding negative case resistance value when the fourth switch is closed and the corresponding negative case resistance value when the preset time is reached;

if the first change value and the second change value are both smaller than a preset value, closing of a first switch (21) is not controlled, and the voltage of a first voltage detection point at the current moment is obtained;

otherwise, controlling the first switch (21) to be closed and acquiring the voltage of the first voltage detection point at the current moment.

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