Insulation detection device and detection method for energy storage system

Abstract

The invention relates to the technical field of battery energy storage, and discloses an insulation detection device and detection method for an energy storage system. The insulation detection device comprises a first parallel branch, a second parallel branch, a third detection resistor, a first sampling module, a second sampling module and a controller, the parallel branches are connected between the positive electrode and the negative electrode of an energy storage unit battery cluster in parallel, and the first parallel branch comprises a positive insulation resistor and a negative insulation resistor which are connected in series. The second parallel branch comprises a first switch bridge arm loop and a second switch bridge arm loop which are connected in series, and the intermediate nodes are connected through a third detection resistor. According to the insulation detection device, the circuit topology structure of the second parallel branch is changed by controlling the on-off states of the two electromagnetic switches during detection. The controller obtains the voltage value of the insulation impedance under the corresponding structure, the resistance value of the insulation impedance is obtained to judge whether the insulation of the energy storage system is safe or not, the measured resistance value is not a negative value, and the accuracy and reliability of detection are improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of energy storage systems, and specifically to an insulation detection device and a detection method for an energy storage system. Background Art

[0002] The battery energy storage system (BESS) consists of a large number of batteries connected in series and parallel to form a battery cluster. The voltage is high when the system is running, and the insulation level of the system directly affects the reliable operation of the equipment. After long-term operation, the insulation level of the battery energy storage system will decrease due to factors such as environmental influences, aging of system equipment, damage to the insulation layer of the wiring harness, and wear of the battery insulation layer.

[0003] Therefore, corresponding devices are needed to carry out necessary monitoring of the insulation level of the energy storage system to improve the reliability and stability of the system operation.

[0004] For insulation detection of energy storage systems, an unbalanced bridge is a commonly used detection device. The Chinese patent with publication number CN11893299A discloses "an insulation detection device and insulation detection method for energy storage systems", which includes a first parallel branch and a second parallel branch connected between the positive and negative electrodes of the energy storage unit. The first parallel branch includes a switch bridge arm and a second resistor R2 connected in series, and the second parallel branch includes a positive insulation resistor R connected in series. x and negative insulation resistance R y The nodes between the first and second parallel branches are connected through a third resistor R3, and the node between the second parallel branch is connected to a ground wire. By controlling the switch state of the switch bridge arm K1, the circuit topology of the first parallel branch is changed to obtain a positive insulation impedance R x The corresponding different voltage information V completes the alignment of the insulation resistance R x and negative insulation resistance R y resistance detection, or to obtain negative insulation resistance R y The corresponding different voltage information is completed to align the insulation resistance R x and negative insulation resistance R y Resistance detection is performed to determine whether the insulation of the energy storage system meets the requirements.

[0005] The inventor of the present application has found that in the technical solution of the above patent, when the positive insulation impedance (or negative insulation impedance) is abnormal, the voltage (V pe and V pe* ) will be related to the total voltage V batThe sampling voltage output by the sampling circuit is also very close. According to the calculation formula of insulation impedance, the sampling voltage in the closed and open states of the switch bridge arm is calculated as the difference (V ba tV pe 、V bat -V pe* or V pe -V pe* ). Since the sampling circuit will have errors, when one of the two sampling voltages deviates to the positive direction and the other deviates to the negative direction, the calculated value will be negative, causing it to be inconsistent with the actual insulation impedance, resulting in failure of the insulation detection device. Even if the accuracy of the sampling circuit components is improved, the phenomenon of negative values ​​cannot be completely eliminated. Summary of the invention

[0006] The object of the present invention is to provide an insulation detection device and a detection method for an energy storage system to solve the problems in the above-mentioned background technology.

[0007] An embodiment of the present invention provides an insulation detection device for an energy storage system, comprising: a first parallel branch, a second parallel branch, a third detection resistor, a first sampling module, a second sampling module and a controller;

[0008] The first parallel branch and the second parallel branch are connected in parallel between the positive electrode and the negative electrode of the energy storage unit battery cluster;

[0009] The first parallel branch includes a positive insulation impedance and a negative insulation impedance connected in series, the second parallel branch includes a first switch bridge arm loop and a second switch bridge arm loop connected in series, and the positive insulation impedance and the first switch bridge arm loop are connected to the positive electrode of the energy storage unit battery cluster;

[0010] The connection point between the positive insulation impedance and the negative insulation impedance is connected to the ground line, and is connected to the connection point between the first switch bridge arm loop and the second switch bridge arm loop through the third detection resistor;

[0011] The two ends of the positive insulation impedance are respectively connected to the input end of the first sampling module, the two ends of the negative insulation impedance are respectively connected to the input end of the second sampling module, the output ends of the first sampling module and the second sampling module are respectively connected to the controller, and the first sampling module and the second sampling module are respectively used to collect the voltage of the positive insulation impedance and the negative insulation impedance;

[0012] By controlling the switching states of the first switch bridge arm loop and the second switch bridge arm loop to change the circuit topology of the second parallel branch, and obtaining different voltage values ​​corresponding to the positive insulation impedance and the negative insulation impedance, resistance detection of the positive insulation impedance and the negative insulation impedance is achieved.

[0013] Based on the above scheme, it can be known that the insulation detection device for energy storage system of the present invention is provided by setting a first parallel branch, a second parallel branch, a third detection resistor, a first sampling module, a second sampling module and a controller. The first parallel branch and the second parallel branch are connected in parallel between the positive electrode and the negative electrode of the energy storage unit battery cluster. The first parallel branch includes a positive insulation impedance and a negative insulation impedance connected in series. The second parallel branch includes a first switch bridge arm loop and a second switch bridge arm loop connected in series. The connection point of the positive insulation impedance and the negative insulation impedance is grounded, and is connected to the connection point of the first switch bridge arm loop and the second switch bridge arm loop through the third detection resistor. The two ends of the positive insulation impedance are connected to the input end of the first sampling module, and the two ends of the negative insulation impedance are connected to the input end of the second sampling module. The output ends of the first sampling module and the second sampling module are respectively connected to the controller. The insulation detection device for energy storage system of the present invention controls the switch states of the first switch bridge arm loop and the second switch bridge arm loop during detection to change the circuit topology of the second parallel branch. The controller obtains different voltage values ​​under corresponding structures on positive insulation impedance and negative insulation impedance through the first sampling module and the second sampling module, and realizes resistance detection of positive insulation impedance and negative insulation impedance through Kirchhoff's current law. Through the difference between the measured resistance values ​​of positive insulation impedance and negative insulation impedance and the standard resistance values ​​of positive insulation impedance and negative insulation impedance, it is judged whether the insulation of the unit battery cluster of the energy storage system meets the requirements. If the difference is within the allowable range, the insulation of the battery cluster of the energy storage system is in a safe state and the system runs normally; if the difference exceeds the allowable range, the insulation of the battery cluster of the energy storage system is unsafe, and an abnormal insulation impedance fault is reported. The phenomenon of negative resistance value of insulation impedance will not appear at all during detection, which improves the accuracy and reliability of insulation detection and has good application prospects.

[0014] In a feasible solution, the first switch bridge arm circuit includes: a first detection resistor and a first electromagnetic switch, wherein the first detection resistor is connected in parallel with the first electromagnetic switch;

[0015] The second switch bridge arm loop includes: a second detection resistor and a second electromagnetic switch, and the second detection resistor is connected in parallel with the second electromagnetic switch.

[0016] In a feasible solution, the first switch bridge arm loop further includes: a fourth detection resistor;

[0017] The fourth detection resistor is connected in series with the first electromagnetic switch to form a first switch branch, and the first switch branch is connected in parallel with the first detection resistor;

[0018] The second switch bridge arm loop further includes: a fifth detection resistor;

[0019] The fifth detection resistor and the second electromagnetic switch are connected in series to form a second switch branch, and the second switch branch is connected in parallel to the second detection resistor.

[0020] In a feasible solution, the first switch bridge arm loop further includes: a sixth detection resistor;

[0021] The first detection resistor is connected in parallel with the first electromagnetic switch and then connected in series with the sixth detection resistor;

[0022] The second switch bridge arm loop further includes: a seventh detection resistor;

[0023] The second detection resistor is connected in parallel with the second electromagnetic switch and then connected in series with the seventh detection resistor.

[0024] In a feasible solution, the first switch bridge arm loop further includes: a fourth detection resistor and a sixth detection resistor;

[0025] The fourth detection resistor is connected in series with the first electromagnetic switch to form a first switch branch, the first switch branch is connected in parallel with the first detection resistor and then connected in series with the sixth detection resistor;

[0026] The second switch bridge arm loop further includes: a fifth detection resistor and a seventh detection resistor;

[0027] The fifth detection resistor and the second electromagnetic switch are connected in series to form a second switch branch. The second switch branch is connected in parallel with the second detection resistor and then connected in series with the seventh detection resistor.

[0028] In a feasible solution, the first switch bridge arm circuit includes: a first electromagnetic switch;

[0029] The second switch bridge arm circuit includes: a second electromagnetic switch and a second detection resistor;

[0030] The second electromagnetic switch is connected in parallel with the second detection resistor.

[0031] In a feasible solution, the first switch bridge arm circuit includes: a first electromagnetic switch and a first detection resistor;

[0032] The first electromagnetic switch is connected in parallel with the first detection resistor;

[0033] The second switch bridge arm circuit includes: a second electromagnetic switch.

[0034] An embodiment of the present invention further provides an insulation detection device for an energy storage system, comprising: a first parallel branch, a second parallel branch, a first sampling module, a second sampling module and a controller;

[0035] The first parallel branch and the second parallel branch are connected in parallel between the positive electrode and the negative electrode of the energy storage unit battery cluster;

[0036] The first parallel branch includes a positive insulation impedance and a negative insulation impedance connected in series with each other;

[0037] The second parallel circuit includes: a first detection resistor, a sixth detection resistor, a second detection resistor, a seventh detection resistor, a first electromagnetic switch and a second electromagnetic switch;

[0038] The first detection resistor, the sixth detection resistor, the second detection resistor and the seventh detection resistor are connected in series in sequence;

[0039] The positive insulation impedance and the first detection resistor are connected to the positive electrode of the energy storage unit battery cluster;

[0040] The connection point between the positive insulation impedance and the negative insulation impedance is connected to a ground wire, and the connection point between the positive insulation impedance and the negative insulation impedance and the connection point between the sixth detection resistor and the second detection resistor are connected;

[0041] One end of the first electromagnetic switch is connected to the connection point of the second detection resistor and the seventh detection resistor, and the other end is connected to the positive electrode of the energy storage unit battery cluster;

[0042] One end of the second electromagnetic switch is connected to the connection point of the first detection resistor and the sixth detection resistor, and the other end is connected to the negative electrode of the energy storage unit battery cluster;

[0043] The two ends of the positive insulation impedance are respectively connected to the input end of the first sampling module, the two ends of the negative insulation impedance are respectively connected to the input end of the second sampling module, the output ends of the first sampling module and the second sampling module are respectively connected to the controller, and the first sampling module and the second sampling module are respectively used to collect the voltage of the positive insulation impedance and the negative insulation impedance;

[0044] By controlling the switching states of the first electromagnetic switch and the second electromagnetic switch to change the circuit topology of the second parallel branch, and obtaining different voltage values ​​corresponding to the positive insulation impedance and the negative insulation impedance, resistance detection of the positive insulation impedance and the negative insulation impedance is achieved.

[0045] In a feasible solution, it further includes: a fourth detection resistor and a fifth detection resistor;

[0046] One end of the fourth detection resistor is connected to the first electromagnetic switch, and the other end is connected to a connection point between the second detection resistor and the seventh detection resistor;

[0047] One end of the fifth detection resistor is connected to the second electromagnetic switch, and the other end is connected to the negative electrode of the energy storage unit battery cluster.

[0048] An embodiment of the present invention further provides an insulation detection method for an energy storage system, including the insulation detection device for an energy storage system in any one of the above designs, and the insulation detection method includes the following steps:

[0049] S1 disconnects the first electromagnetic switch and the second electromagnetic switch, and establishes a node current relationship according to Kirchhoff's current law;

[0050] The S2 controller collects the voltages on the positive insulation impedance and the negative insulation impedance respectively through the first sampling module and the second sampling module, compares the voltage values ​​on the positive insulation impedance and the negative insulation impedance, and performs the following operations according to the comparison results;

[0051] S3: If the voltage value of the positive insulation impedance is greater than the voltage value of the negative insulation impedance, the first electromagnetic switch is closed and the second electromagnetic switch remains in an open state; the controller collects the closed voltage on the positive insulation impedance through the first sampling module, and establishes a relationship corresponding to the node current according to Kirchhoff's current law;

[0052] S4 combines the relationship equations in step S1 and S3 to obtain the resistance values ​​of the positive insulation resistance and the negative insulation resistance;

[0053] S5: If the voltage value of the positive insulation impedance is not greater than the voltage value of the negative insulation impedance, the second electromagnetic switch is closed, and the first electromagnetic switch remains in an open state; the controller collects the closed voltage on the negative insulation impedance through the second sampling module, and establishes a relationship corresponding to the node current according to Kirchhoff's current law;

[0054] S6 combines the relationship in step S1 and step S5 to obtain the resistance values ​​of the positive insulation resistance and the negative insulation resistance;

[0055] S7 determines whether the insulation of the battery pack of the energy storage system meets the requirements according to the difference between the obtained resistance values ​​of the positive insulation impedance and the negative insulation impedance and the standard resistance value.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. The insulation detection device and detection method of the present invention will not cause the insulation impedance to be negative during detection, completely eliminating the hidden danger of the insulation impedance to be negative, and improving the accuracy and reliability of insulation detection.

[0058] 2. The present invention optimizes the design of the insulation detection device, improves circuit reliability, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in 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 labor.

[0060] Figure 1 This is a schematic diagram of an insulation detection device for an energy storage system in Embodiment 1 of the present invention;

[0061] Figure 2 Schematic diagram of an insulation detection device for an energy storage system in Embodiment 2 of the present invention;

[0062] Figure 3 Schematic diagram of an insulation detection device for an energy storage system in Embodiment 3 of the present invention;

[0063] Figure 4 Schematic diagram of an insulation detection device for an energy storage system in a fourth embodiment of the present invention;

[0064] Figure 5 This is a schematic diagram of an insulation detection device for an energy storage system in a fifth embodiment of the present invention;

[0065] Figure 6 Schematic diagram of an insulation detection device for an energy storage system in a sixth embodiment of the present invention;

[0066] Figure 7 Schematic diagram of an insulation detection device for an energy storage system in Embodiment 7 of the present invention;

[0067] Figure 8 Schematic diagram of an insulation detection device for an energy storage system in Embodiment 8 of the present invention;

[0068] Fig. 9 It is a flowchart of the insulation detection method for an energy storage system in Embodiment 9 of the present invention. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments 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.

[0070] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0071] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0073] As described in the background technology of this application, the voltage of the battery energy storage system is relatively high during operation, and the insulation level of the system directly affects the reliable operation of the equipment. After long-term operation, the insulation level of the battery energy storage system will decrease due to factors such as environmental influences, aging of system equipment, damage to the wiring harness insulation layer, and wear of the battery insulation layer. Therefore, corresponding devices are required to perform necessary monitoring of the insulation level of the energy storage system to improve the reliability and stability of the system operation.

[0074] Regarding the insulation detection of energy storage systems, the Chinese patent with publication number CN11893299A discloses "an insulation detection device and insulation detection method for energy storage systems", which includes a first parallel branch and a second parallel branch connected between the positive and negative electrodes of the energy storage unit, the first parallel branch includes a switch bridge arm and a second resistor R2 connected in series, and the second parallel branch includes a positive insulation resistor R connected in series. x and negative insulation resistance R y The nodes between the first and second parallel branches are connected through a third resistor R3, and the node between the second parallel branch is connected to a ground wire. By controlling the switch state of the switch bridge arm K1, the circuit topology of the first parallel branch is changed to obtain a positive insulation impedance R xThe corresponding different voltage information V completes the alignment of the insulation resistance R x and negative insulation resistance R y resistance detection, or to obtain negative insulation resistance R y The corresponding different voltage information is completed to align the insulation resistance R x and negative insulation resistance R y Resistance detection is performed to determine whether the insulation of the energy storage system meets the requirements.

[0075] The inventor of the present application has found that in the technical solution of the above patent, when the positive insulation impedance (or negative insulation impedance) is abnormal, the voltage (V pe and V pe* ) will be related to the total voltage V bat The sampling voltage output by the sampling circuit is also very close. According to the calculation formula of insulation impedance, the sampling voltage in the closed and open states of the switch bridge arm is calculated as the difference (V ba tV pe 、V bat -V pe* or V pe -V pe* ). Since the sampling circuit may have errors, when one of the two sampling voltages deviates to the positive direction and the other deviates to the negative direction, the calculated value will be negative, resulting in a discrepancy with the actual insulation impedance, causing the insulation detection device to fail. Even if the accuracy of the sampling circuit components is improved, the phenomenon of negative values ​​cannot be completely eliminated.

[0076] In order to solve the above problems, the inventor of the present application proposed the technical solution of the present application, and the specific embodiments are as follows:

[0077] The insulation detection device for an energy storage system of this embodiment includes: a first parallel branch, a second parallel branch, a third detection resistor R3, a first sampling module, a second sampling module and a controller.

[0078] The first parallel branch and the second parallel branch are connected in parallel between the positive electrode BAT+ and the negative electrode BAT- of the energy storage unit battery cluster.

[0079] The first parallel branch includes: positive insulation resistance R + And negative insulation resistance R-, positive insulation resistance R + In series with the negative insulation resistance R-, the positive insulation resistance R + The other end of the negative insulation resistance R- is respectively connected to the positive electrode BAT+ and the negative electrode BAT- of the energy storage unit battery cluster.

[0080] The second parallel branch includes: a first switch bridge arm loop and a second switch bridge arm loop.

[0081] The first switch bridge arm loop and the second switch bridge arm loop are connected in series, and the other ends of the first switch bridge arm loop and the second switch bridge arm loop are respectively connected to the positive electrode BAT+ and the negative electrode BAT- of the energy storage unit battery cluster.

[0082] Positive insulation resistance R + The connection point N with the negative insulation impedance R- is grounded, and the connection point M of the first switch bridge arm loop and the second switch bridge arm loop, the positive insulation impedance R + A connection point N with the negative insulation resistance R- is connected via a third detection resistor R3.

[0083] Positive insulation resistance R + The two ends of are respectively connected to the input end of the first sampling module, the two ends of the negative insulation resistance R- are respectively connected to the input end of the second sampling module, and the output ends of the first sampling module and the second sampling module are respectively connected to the controller. The first sampling module and the second sampling module can be any one of an AD sampling circuit, an integrated sampling chip or a module, respectively used to collect the positive insulation resistance R + and the voltage across the negative insulation resistance R-.

[0084] In this embodiment, the circuit topology of the second parallel branch is changed by controlling the on / off state of the first switch bridge arm loop and the second switch bridge arm loop. The controller obtains the positive insulation impedance R + The voltage value of the negative insulation resistance R- in the corresponding state is realized by Kirchhoff's current law to realize the positive insulation resistance R + And the resistance detection of negative insulation resistance R-. Through the positive insulation resistance R + The difference between the measured resistance value and the standard resistance value, as well as the difference between the measured resistance value and the standard resistance value of the negative insulation impedance R-, are used to determine whether the insulation performance of the energy storage unit battery cluster meets the requirements.

[0085] It is not difficult to find from the above content that the insulation detection device for energy storage system of this embodiment is provided with a first parallel branch, a second parallel branch, a third detection resistor, a first sampling module, a second sampling module and a controller. The first parallel branch and the second parallel branch are connected in parallel between the positive electrode and the negative electrode of the energy storage unit battery cluster. The first parallel branch includes a positive insulation impedance and a negative insulation impedance connected in series with each other. The second parallel branch includes a first switch bridge arm loop and a second switch bridge arm loop connected in series with each other. The connection point of the positive insulation impedance and the negative insulation impedance is grounded, and is connected to the connection point of the first switch bridge arm loop and the second switch bridge arm loop through the third detection resistor. The two ends of the positive insulation impedance are connected to the input end of the first sampling module, and the two ends of the negative insulation impedance are connected to the input end of the second sampling module. The output ends of the first sampling module and the second sampling module are respectively connected to the controller. The insulation detection device for energy storage system of this embodiment controls the switch states of the first switch bridge arm loop and the second switch bridge arm loop during detection to change the circuit topology of the second parallel branch. The controller obtains different voltage values ​​of positive insulation impedance and negative insulation impedance under corresponding structures through the first sampling module and the second sampling module, and realizes resistance detection of positive insulation impedance and negative insulation impedance through Kirchhoff's current law. Through the difference between the measured resistance values ​​of positive insulation impedance and negative insulation impedance and the standard resistance values ​​of positive insulation impedance and negative insulation impedance, it is judged whether the insulation of the unit battery cluster of the energy storage system meets the requirements. If the difference is within the allowable range, the insulation of the battery cluster of the energy storage system is in a safe state and the system runs normally; if the difference exceeds the allowable range, the insulation of the battery cluster of the energy storage system is unsafe, and an abnormal insulation impedance fault is reported. The phenomenon of negative insulation impedance resistance will not occur at all during detection, which improves the accuracy and reliability of insulation detection and has good application prospects.

[0086] Embodiment 1

[0087] Figure 1 Schematic diagram of an insulation detection device for an energy storage system in Embodiment 1 of the present invention.

[0088] like Figure 1 As shown, in the insulation detection device for the energy storage system in this embodiment, the first switch bridge arm circuit includes: a first detection resistor R1 and a first electromagnetic switch K1.

[0089] The second switch bridge arm loop includes: a second detection resistor R2 and a second electromagnetic switch K2.

[0090] The first detection resistor R1 and the first electromagnetic switch K1 are connected in parallel to form a first switch bridge arm loop, the second detection resistor R2 and the second electromagnetic switch K2 are connected in parallel to form a second switch bridge arm loop, and then the two are connected in series to form a second parallel branch.

[0091] The first electromagnetic switch K1 and the second electromagnetic switch K2 can be any one of an electromagnetic relay, a controllable switch tube or an optical coupler.

[0092] In this embodiment, the first detection resistor R1, the second detection resistor R2, the third detection resistor R3, the positive insulation resistance R + The positive insulation impedance R- and the negative insulation impedance R- form a balanced bridge. By changing the switching state of the first electromagnetic switch K1 and the second electromagnetic switch K2, the circuit topology of the balanced bridge is changed, and the controller obtains the positive insulation impedance R + And the voltage value of negative insulation resistance R- in the corresponding state, so as to realize the detection and monitoring of the insulation performance of the energy storage unit battery cluster.

[0093] Embodiment 2

[0094] Figure 2 This is a schematic diagram of an insulation detection device for an energy storage system in a second embodiment of the present invention. The second embodiment is an alternative to the first embodiment.

[0095] like Figure 2 As shown, in the insulation detection device for the energy storage system of this embodiment, the first switch bridge arm circuit includes: a first detection resistor R1, a first electromagnetic switch K1 and a fourth detection resistor R4.

[0096] The fourth detection resistor R4 is connected in series with the first electromagnetic switch K1 to form a first switch branch, and then the first switch branch is connected in parallel with the first detection resistor R1 to form a first switch bridge arm loop.

[0097] The second switch bridge arm loop includes: a second detection resistor R2, a second electromagnetic switch K2 and a fifth detection resistor R5.

[0098] The fifth detection resistor R5 is connected in series with the second electromagnetic switch K2 to form a second switch branch, and then the second switch branch is connected in parallel with the second detection resistor R2 to form a second switch bridge arm loop.

[0099] Then, the first switch bridge arm loop is connected in series with the second switch bridge arm loop to form a second parallel branch.

[0100] Embodiment 3

[0101] Figure 3 This is a schematic diagram of an insulation detection device for an energy storage system in Embodiment 3 of the present invention. Embodiment 3 is an alternative to Embodiment 1.

[0102] like Figure 3 As shown, in the insulation detection device for the energy storage system of this embodiment, the first switch bridge arm circuit includes: a first detection resistor R1, a first electromagnetic switch K1 and a sixth detection resistor R6.

[0103] The first detection resistor R1 is connected in parallel with the first electromagnetic switch K1 . The first detection resistor R1 and the first electromagnetic switch K1 are connected in parallel and then connected in series with the sixth detection resistor R6 to form a first switch bridge arm loop.

[0104] The second switch bridge arm loop includes: a second detection resistor R2, a second electromagnetic switch K2 and a seventh detection resistor R7.

[0105] The second detection resistor R2 is connected in parallel with the second electromagnetic switch K2. The second detection resistor R2 is connected in parallel with the second electromagnetic switch K2 and then connected in series with the seventh detection resistor R7 to form a second switch bridge arm loop.

[0106] Embodiment 4

[0107] Figure 4 This is a schematic diagram of an insulation detection device for an energy storage system in a fourth embodiment of the present invention. The fourth embodiment is an alternative to the first embodiment.

[0108] like Figure 4 As shown, in the insulation detection device for the energy storage system of this embodiment, the first switch bridge arm circuit includes: a first detection resistor R1, a first electromagnetic switch K1, a fourth detection resistor R4 and a sixth detection resistor R6.

[0109] The first electromagnetic switch K1 is connected in series with the fourth detection resistor R4 to form a first switch branch. The first switch branch is connected in parallel with the first detection resistor R1 and then in series with the sixth detection resistor R6 to form a first switch bridge arm loop.

[0110] The second switch bridge arm loop includes: a second detection resistor R2, a second electromagnetic switch K2, a fifth detection resistor R5 and a seventh detection resistor R7.

[0111] The second electromagnetic switch K2 is connected in series with the fifth detection resistor R5 to form a second switch branch. The second switch branch is connected in parallel with the second detection resistor R2, and then connected in series with the seventh detection resistor R7 to form a second switch bridge arm loop.

[0112] Embodiment 5

[0113] Figure 5 This is a schematic diagram of an insulation detection device for an energy storage system in a fifth embodiment of the present invention. The fifth embodiment is an alternative to the first embodiment.

[0114] like Figure 5 As shown, in the insulation detection device for the energy storage system of this embodiment, the first switch bridge arm circuit includes: a first electromagnetic switch K1, that is, the first switch bridge arm circuit only has the first electromagnetic switch K1, and no detection resistor is provided.

[0115] The second switch bridge arm loop includes: a second electromagnetic switch K2 and a second detection resistor R2.

[0116] The second electromagnetic switch K2 is connected in parallel with the second detection resistor R2 to form a second switch bridge arm loop, and then connected in series with the first electromagnetic switch K1 to form a second parallel branch.

[0117] Embodiment 6

[0118] Figure 6 This is a schematic diagram of an insulation detection device for an energy storage system in Embodiment 6 of the present invention. Embodiment 6 is an alternative to Embodiment 1.

[0119] like Figure 6 As shown, in the insulation detection device for the energy storage system of this embodiment, the first switch bridge arm circuit includes: a first electromagnetic switch K1 and a first detection resistor R1.

[0120] The second switch bridge arm loop includes: a second electromagnetic switch K2, that is, the second switch bridge arm loop only has the second electromagnetic switch K2, and no detection resistor is provided.

[0121] The first electromagnetic switch K1 is connected in parallel with the first detection resistor R1 to form a first switch bridge arm loop, and then connected in series with the second electromagnetic switch K2 to form a second parallel branch.

[0122] Embodiment 7

[0123] Figure 7 This is a schematic diagram of an insulation detection device for an energy storage system in Embodiment 7 of the present invention.

[0124] like Figure 7 As shown, the insulation detection device for an energy storage system of this embodiment includes: a first parallel branch, a second parallel branch, a first sampling module, a second sampling module and a controller.

[0125] The first parallel branch and the second parallel branch are connected in parallel between the positive electrode BAT+ and the negative electrode BAT- of the energy storage unit battery cluster.

[0126] The first parallel branch includes: positive insulation resistance R + And negative insulation resistance R-, positive insulation resistance R + In series with the negative insulation resistance R-, the positive insulation resistance R + The other end of the negative insulation resistance R- is respectively connected to the positive electrode BAT+ and the negative electrode BAT- of the energy storage unit battery cluster.

[0127] The second parallel circuit includes: a first detection resistor R1, a sixth detection resistor R6, a second detection resistor R2, a seventh detection resistor R7, a first electromagnetic switch K1 and a second electromagnetic switch K2.

[0128] The first detection resistor R1, the sixth detection resistor R6, the second detection resistor R2 and the seventh detection resistor R7 are connected in series in sequence, and the other end of the first detection resistor R1 is connected to the positive electrode BAT+ of the energy storage unit battery cluster, and the other end of the seventh detection resistor R7 is connected to the negative electrode BAT- of the energy storage unit battery cluster.

[0129] Positive insulation resistance R + A connection point N with the negative insulation resistance R− is grounded, and the connection point N is directly connected to a connection point M between the sixth detection resistor R6 and the second detection resistor R2 .

[0130] One end of the first electromagnetic switch K1 is connected to the connection point between the second detection resistor R2 and the seventh detection resistor R7 , and the other end of the first electromagnetic switch K1 is connected to the positive electrode BAT+ of the energy storage unit battery cluster.

[0131] One end of the second electromagnetic switch K2 is connected to the connection point of the first detection resistor R1 and the sixth detection resistor R6 , and the other end of the second electromagnetic switch K2 is connected to the negative electrode BAT− of the energy storage unit battery cluster.

[0132] Positive insulation resistance R + The two ends of are respectively connected to the input end of the first sampling module, the two ends of the negative insulation resistance R- are respectively connected to the input end of the second sampling module, and the output ends of the first sampling module and the second sampling module are respectively connected to the controller. The output ends of the first sampling module and the second sampling module are respectively connected to the controller. The first sampling module and the second sampling module can be any one of an AD sampling circuit, an integrated sampling chip or a module, respectively used to collect the positive insulation resistance R + and the voltage across the negative insulation resistance R-.

[0133] It should be noted that: in the insulation detection device of this embodiment, when K1 is closed and K2 is disconnected, the second detection resistor "R2" is equivalent to the third detection resistor "R3" in Example 1; when K2 is closed and K1 is disconnected, the sixth detection resistor "R6" is equivalent to the third detection resistor "R3" in Example 1; when K1 and K2 are both disconnected, "R1+R6" is equivalent to "R1" in Example 1, and "R2+R7" is equivalent to "R2" in Example 1.

[0134] In this embodiment, the positive insulation resistance R + , negative insulation resistance R-, first detection resistor R1, sixth detection resistor R6, second detection resistor R2, seventh detection resistor R7, first electromagnetic switch K1 and second electromagnetic switch K2 constitute an unbalanced bridge. By controlling the switching state of the first electromagnetic switch K1 and the second electromagnetic switch K2, the circuit topology of the unbalanced bridge is changed. The controller obtains the positive insulation resistance R through the sampling module +The voltage value of the negative insulation resistance R- in the corresponding state is realized by Kirchhoff's current law to realize the positive insulation resistance R + And the resistance detection of negative insulation resistance R-. Through the positive insulation resistance R + The difference between the measured resistance value and the standard resistance value, and the difference between the measured resistance value and the standard resistance value of the negative insulation resistance R- can be used to judge whether the insulation performance of the energy storage unit battery cluster meets the requirements.

[0135] Embodiment 8

[0136] Figure 8 This is a schematic diagram of an insulation detection device for an energy storage system in Embodiment 8 of the present invention. Embodiment 8 is an alternative to Embodiment 7.

[0137] like Figure 8 As shown, the insulation detection device for the energy storage system of this embodiment further includes: a fourth detection resistor R4 and a fifth detection resistor R5.

[0138] The connection point of the first detection resistor R1 and the sixth detection resistor R6 is connected to one end of the second electromagnetic switch K2, the other end of the second electromagnetic switch K2 is connected to one end of the fifth detection resistor R5, and the other end of the fifth detection resistor R5 is connected to the negative electrode BAT- of the energy storage unit battery cluster.

[0139] The connection point between the second detection resistor R2 and the seventh detection resistor R7 is connected to one end of the fourth detection resistor R4, the other end of the fourth detection resistor R4 is connected to one end of the first electromagnetic switch K1, and the other end of the first electromagnetic switch K1 is connected to the positive electrode BAT+ of the energy storage unit battery cluster.

[0140] Embodiment 9

[0141] Fig. 9 It is a flowchart of the insulation detection method for an energy storage system in Embodiment 9 of the present invention.

[0142] The invention also provides an insulation detection method for an energy storage system.

[0143] like Fig. 9 As shown, the insulation detection method for the energy storage system of this embodiment includes all the insulation detection devices for the energy storage system in all the above embodiments, and the insulation detection method includes the following steps:

[0144] S1 disconnects the first electromagnetic switch K1 and the second electromagnetic switch K2, so that the first electromagnetic switch K1 and the second electromagnetic switch K2 are both in the disconnected state. According to Kirchhoff's current law (KCL), the node current relationship between the connection point M and the connection point N in this structural state is established, that is, the initial voltage V M and the initial voltage V at the connection point N PEThe relationship between:

[0145]

[0146] Among them, V BAT Represents the total voltage V of the energy storage system battery cluster 总 , V PE Represents the initial voltage at the connection point N, V M represents the initial voltage at the connection point M, R + represents the resistance value of positive insulation resistance, R- represents the resistance value of negative insulation resistance, R1 represents the resistance value of the first detection resistor, R2 represents the resistance value of the second detection resistor, and R3 represents the resistance value of the third detection resistor.

[0147] It should be noted that: in the structures of the seventh and eighth embodiments, since the connection point M is directly connected to the connection point N, V M =V PE , where “V M -V PE ” is 0; and when K1 and K2 are both disconnected, “R1” in the formula is “R1+R6”, and “R2” in the formula is “R2+R7”.

[0148] The S2 controller collects the positive insulation resistance R through the first sampling module + The first initial voltage V + The second sampling module collects the second initial voltage V- of the negative insulation impedance R-, and then the controller compares the positive insulation impedance R + The first initial voltage V + The voltage value of the second initial voltage V- of the negative insulation resistance R- is compared, and the following operations are performed according to the comparison result:

[0149] S3 If the positive insulation resistance R + The first initial voltage V + The value is greater than the value of the second initial voltage V- of the negative insulation resistance R-, that is, if V + >V-, the first electromagnetic switch K1 is closed, and the second electromagnetic switch K2 remains open. At this time, the voltage value of the connection point M becomes V BAT .

[0150] The controller collects the positive insulation resistance R under this structure through the first sampling module + The first closing voltage V +* According to Kirchhoff's current law (KCL), the relationship corresponding to the node current in this structural state is established:

[0151]

[0152] Among them, V BATRepresents the total voltage V of the energy storage system battery cluster 总 , R + represents the resistance value of positive insulation resistance, R- represents the resistance value of negative insulation resistance, R3 represents the resistance value of the third detection resistor, V +* Indicates the positive insulation resistance R after closing the first electromagnetic switch K1 + Closing voltage of

[0153] It should be noted that in the structures of the seventh and eighth embodiments, "R3" in the formula is "R2".

[0154] S4 combines the equations (1), (2) and (3) in steps S1 and S3 to obtain the positive insulation resistance R + The resistance value of the negative insulation resistance R-.

[0155] S5 If the positive insulation resistance R + The first initial voltage V + The value is not greater than the second initial voltage V-value of the negative insulation resistance R-, that is, if V + ≤V-, the second electromagnetic switch K2 is closed, and the first electromagnetic switch K1 remains in the open state. At this time, the voltage value of the connection point M becomes 0.

[0156] The controller collects the second closed voltage V of the negative insulation impedance R- under this structure through the second sampling module. -* According to Kirchhoff's current law (KCL), the relationship corresponding to the node current in this structural state is established:

[0157]

[0158] Among them, V BAT Represents the total voltage V of the energy storage system battery cluster 总 , V -* Represents the closing voltage of the negative insulation impedance R- after closing the second electromagnetic switch K2, R + represents the resistance value of positive insulation impedance, R- represents the resistance value of negative insulation impedance, and R3 represents the resistance value of the third detection resistor.

[0159] It should be noted that in the structures of the seventh and eighth embodiments, "R3" in the formula is "R6".

[0160] S6 combines the equations (1), (2) and (4) in steps S1 and S5 to obtain the positive insulation resistance R + The resistance value of the negative insulation resistance R-.

[0161] S7 determines whether the insulation of the energy storage system battery cluster meets the safety requirements based on the difference between the resistance values ​​of the positive insulation impedance R+ and the negative insulation impedance R- measured in step S4 or step S6 and the standard resistance values ​​of the positive insulation impedance R+ and the negative insulation impedance R-. If the difference is within the allowable range, the insulation of the energy storage system battery cluster meets the safety requirements and the system operates normally; if the difference exceeds the allowable range, the insulation of the energy storage system battery cluster is unsafe, and the controller reports an abnormal insulation impedance fault.

[0162] In the present invention, unless otherwise clearly specified and limited, a first feature being “on” or “under” a second feature may mean that the first feature and the second feature are in direct contact, or the first feature and the second feature are in indirect contact via an intermediate medium.

[0163] Moreover, the first feature being “above”, “above”, and “above” the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being “below”, “below”, and “below” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0164] 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, without contradiction.

[0165] 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 replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An insulation detection device for an energy storage system, characterized in that: include: A first parallel branch, a second parallel branch, a third detection resistor, a first sampling module, a second sampling module and a controller; The first parallel branch and the second parallel branch are connected in parallel between the positive electrode and the negative electrode of the energy storage unit battery cluster; The first parallel branch includes a positive insulation impedance and a negative insulation impedance connected in series, and the second parallel branch includes a first switch bridge arm loop and a second switch bridge arm loop connected in series, and the positive insulation impedance and the first switch bridge arm loop are respectively connected to the positive electrode of the energy storage unit battery cluster; The connection point between the positive insulation impedance and the negative insulation impedance is connected to the ground line, and is connected to the connection point between the first switch bridge arm loop and the second switch bridge arm loop through the third detection resistor; The two ends of the positive insulation impedance are respectively connected to the input end of the first sampling module, the two ends of the negative insulation impedance are respectively connected to the input end of the second sampling module, the output ends of the first sampling module and the second sampling module are respectively connected to the controller, and the first sampling module and the second sampling module are respectively used to collect the voltage of the positive insulation impedance and the negative insulation impedance; By controlling the switching states of the first switch bridge arm loop and the second switch bridge arm loop to change the circuit topology of the second parallel branch, and obtaining different voltage values ​​corresponding to the positive insulation impedance and the negative insulation impedance, resistance detection of the positive insulation impedance and the negative insulation impedance is achieved.

2. The insulation detection device for an energy storage system according to claim 1, characterized in that: The first switch bridge arm circuit includes: a first detection resistor and a first electromagnetic switch, wherein the first detection resistor is connected in parallel with the first electromagnetic switch; The second switch bridge arm loop includes: a second detection resistor and a second electromagnetic switch, and the second detection resistor is connected in parallel with the second electromagnetic switch.

3. The insulation detection device for an energy storage system according to claim 2, characterized in that: The first switch bridge arm loop further includes: a fourth detection resistor; The fourth detection resistor is connected in series with the first electromagnetic switch to form a first switch branch, and the first switch branch is connected in parallel with the first detection resistor; The second switch bridge arm loop further includes: a fifth detection resistor; The fifth detection resistor and the second electromagnetic switch are connected in series to form a second switch branch, and the second switch branch is connected in parallel to the second detection resistor.

4. The insulation detection device for an energy storage system according to claim 2, characterized in that: The first switch bridge arm loop further includes: a sixth detection resistor; The first detection resistor is connected in parallel with the first electromagnetic switch and then connected in series with the sixth detection resistor; The second switch bridge arm loop further includes: a seventh detection resistor; The second detection resistor is connected in parallel with the second electromagnetic switch and then connected in series with the seventh detection resistor.

5. The insulation detection device for an energy storage system according to claim 2, characterized in that: The first switch bridge arm loop further includes: a fourth detection resistor and a sixth detection resistor; The fourth detection resistor is connected in series with the first electromagnetic switch to form a first switch branch, the first switch branch is connected in parallel with the first detection resistor and then connected in series with the sixth detection resistor; The second switch bridge arm loop further includes: a fifth detection resistor and a seventh detection resistor; The fifth detection resistor and the second electromagnetic switch are connected in series to form a second switch branch. The second switch branch is connected in parallel with the second detection resistor and then connected in series with the seventh detection resistor.

6. The insulation detection device for an energy storage system according to claim 1, characterized in that: The first switch bridge arm circuit includes: a first electromagnetic switch; The second switch bridge arm circuit includes: a second electromagnetic switch and a second detection resistor; The second electromagnetic switch is connected in parallel with the second detection resistor.

7. The insulation detection device for an energy storage system according to claim 1, characterized in that: The first switch bridge arm circuit includes: a first electromagnetic switch and a first detection resistor; The first electromagnetic switch is connected in parallel with the first detection resistor; The second switch bridge arm circuit includes: a second electromagnetic switch.

8. An insulation detection device for an energy storage system, characterized in that: include: A first parallel branch, a second parallel branch, a first sampling module, a second sampling module and a controller; The first parallel branch and the second parallel branch are connected in parallel between the positive electrode and the negative electrode of the energy storage unit battery cluster; The first parallel branch includes a positive insulation impedance and a negative insulation impedance connected in series with each other; The second parallel circuit includes: a first detection resistor, a sixth detection resistor, a second detection resistor, a seventh detection resistor, a first electromagnetic switch and a second electromagnetic switch; The first detection resistor, the sixth detection resistor, the second detection resistor and the seventh detection resistor are connected in series in sequence; The positive insulation impedance and the first detection resistor are connected to the positive electrode of the energy storage unit battery cluster; A connection point between the positive insulation impedance and the negative insulation impedance is connected to a ground line, and the connection point is connected to a connection point between the sixth detection resistor and the second detection resistor; One end of the first electromagnetic switch is connected to the connection point of the second detection resistor and the seventh detection resistor, and the other end is connected to the positive electrode of the energy storage unit battery cluster; One end of the second electromagnetic switch is connected to the connection point of the first detection resistor and the sixth detection resistor, and the other end is connected to the negative electrode of the energy storage unit battery cluster; The two ends of the positive insulation impedance are respectively connected to the input end of the first sampling module, the two ends of the negative insulation impedance are respectively connected to the input end of the second sampling module, the output ends of the first sampling module and the second sampling module are respectively connected to the controller, and the first sampling module and the second sampling module are respectively used to collect the voltage of the positive insulation impedance and the negative insulation impedance; By controlling the switching states of the first electromagnetic switch and the second electromagnetic switch to change the circuit topology of the second parallel branch, and obtaining different voltage values ​​corresponding to the positive insulation impedance and the negative insulation impedance, resistance detection of the positive insulation impedance and the negative insulation impedance is achieved.

9. The insulation detection device for an energy storage system according to claim 8, characterized in that: Also includes: a fourth detection resistor and a fifth detection resistor; One end of the fourth detection resistor is connected to the first electromagnetic switch, and the other end is connected to a connection point between the second detection resistor and the seventh detection resistor; One end of the fifth detection resistor is connected to the second electromagnetic switch, and the other end is connected to the negative electrode of the energy storage unit battery cluster.

10. An insulation detection method for an energy storage system, characterized in that: The insulation detection device for an energy storage system according to any one of claims 1 to 9, wherein the insulation detection method comprises the following steps: S1 disconnects the first electromagnetic switch and the second electromagnetic switch, and establishes a node current relationship according to Kirchhoff's current law; The S2 controller collects the voltages on the positive insulation impedance and the negative insulation impedance respectively through the first sampling module and the second sampling module, compares the voltage values ​​on the positive insulation impedance and the negative insulation impedance, and performs the following operations according to the comparison results; S3: If the voltage value of the positive insulation impedance is greater than the voltage value of the negative insulation impedance, the first electromagnetic switch is closed and the second electromagnetic switch remains in an open state; the controller collects the closed voltage on the positive insulation impedance through the first sampling module, and establishes a relationship corresponding to the node current according to Kirchhoff's current law; S4 combines the relationship equations in step S1 and S3 to obtain the resistance values ​​of the positive insulation resistance and the negative insulation resistance; S5: If the voltage value of the positive insulation impedance is not greater than the voltage value of the negative insulation impedance, the second electromagnetic switch is closed, and the first electromagnetic switch remains in an open state; the controller collects the closed voltage on the negative insulation impedance through the second sampling module, and establishes a relationship corresponding to the node current according to Kirchhoff's current law; S6 combines the relationship in step S1 and step S5 to obtain the resistance values ​​of the positive insulation resistance and the negative insulation resistance; S7 determines whether the insulation of the battery pack of the energy storage system meets the requirements according to the difference between the resistance values ​​of the obtained positive insulation resistance and the negative insulation resistance and the standard resistance value.

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