Energy storage system

Abstract

The embodiment of the invention provides an energy storage system. The energy storage system comprises an insulation detection circuit and a battery pack composed of at least one battery module, the battery module comprises a battery cell, a metal plate, a first insulating sheet and a metal shell, the battery cell is arranged in the metal plate, the metal plate is arranged on the first insulating sheet, and the first insulating sheet is arranged on the metal shell; the insulation detection circuit is connected with the metal plate and used for detecting insulation resistance of the positive electrode and / or the negative electrode of the battery pack to the metal plate. Due to the fact that the battery cell is arranged in the metal plate, when the battery cell leaks liquid, the electrolyte can naturally flow to a gap between the battery cell and the metal plate, and the insulation resistance between the battery cell and the metal plate which leak the liquid can be obviously reduced. On the basis, the positive electrode and the negative electrode of the battery pack are connected with the battery core, so that whether the battery core leaks liquid or not can be judged by detecting the insulation resistance of the positive electrode and / or the negative electrode of the battery pack to the metal plate.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage, and in particular to an energy storage system. Background Art

[0002] In energy storage systems, inverters are key devices that connect battery packs to power grids or loads. Currently, non-isolated inverters are gradually being used in energy storage systems due to their simplified structure and low cost.

[0003] However, the non-isolated inverter eliminates the electrical isolation elements between the DC side (battery pack) and the AC side (grid or load), which means that electrical changes on the AC side may be transmitted to the DC side, causing leakage in the battery pack cells, thereby affecting the safety of the energy storage system. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide an energy storage system to detect battery cell leakage and ensure the safety of the energy storage system. The specific technical solution is as follows:

[0005] An embodiment of the present application provides an energy storage system, comprising: an insulation detection circuit and a battery pack consisting of at least one battery module;

[0006] The battery module comprises: a battery cell, a metal plate, a first insulating sheet and a metal shell, wherein the battery cell is arranged in the metal plate, the metal plate is arranged on the first insulating sheet, and the first insulating sheet is arranged on the metal shell;

[0007] The insulation detection circuit is connected to the metal plate and is used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate, wherein the insulation impedance is used to detect whether the battery cell is leaking.

[0008] Optionally, the insulation detection circuit includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, a second switch, a third switch and a control unit;

[0009] The first end of the first resistor is connected to the positive electrode of the battery pack, the second end of the first resistor is connected to the first end of the first switch, and the second end of the first switch is connected to the first end of the third switch;

[0010] A first end of the second resistor is connected to the positive electrode of the battery pack, and a second end of the second resistor is connected to the first end of the third switch;

[0011] The first end of the third resistor is connected to the negative electrode of the battery pack, the second end of the third resistor is connected to the first end of the second switch, and the second end of the second switch is connected to the first end of the third switch;

[0012] A first end of the fourth resistor is connected to the negative electrode of the battery pack, and a second end of the fourth resistor is connected to the first end of the third switch;

[0013] The second end of the third switch is connected to the metal plate;

[0014] The control unit is used to detect the voltage of the fourth resistor, and determine the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate according to the voltage of the fourth resistor;

[0015] The control unit is further configured to detect the total voltage of the battery pack when the first switch, the second switch and the third switch are all disconnected.

[0016] Optionally, the control unit is specifically used to detect the voltage of the fourth resistor to obtain a first voltage when the first switch and the third switch are closed and the second switch is open, and to detect the voltage of the fourth resistor to obtain a second voltage when the second switch and the third switch are closed and the first switch is open, and to calculate the first insulation impedance of the positive electrode of the battery pack to the metal plate and / or the second insulation impedance of the negative electrode of the battery pack to the metal plate based on the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the second resistor, the resistance value of the third resistor, the resistance value of the fourth resistor and the total voltage of the battery pack.

[0017] Optionally, the insulation detection circuit includes: a first resistor, a third resistor, a fourth resistor, a first switch, a second switch and a control unit, and the energy storage system further includes: a voltage detection device;

[0018] A first end of the first resistor is connected to the positive electrode of the battery pack, a second end of the first resistor is connected to a first end of the first switch, and a second end of the first switch is connected to the metal plate;

[0019] A first end of the third resistor is connected to the negative electrode of the battery pack, a second end of the third resistor is connected to a first end of the second switch, and a second end of the second switch is connected to the metal plate;

[0020] A first end of the fourth resistor is connected to the negative electrode of the battery pack, and a second end of the fourth resistor is connected to the metal plate;

[0021] The control unit is used to detect the voltage of the fourth resistor, and determine the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate according to the voltage of the fourth resistor;

[0022] The voltage detection device is used to detect the total voltage of the battery pack.

[0023] Optionally, the control unit is specifically used to detect the voltage of the fourth resistor to obtain a first voltage when the first switch is closed and the second switch is open, and to detect the voltage of the fourth resistor to obtain a second voltage when the second switch is closed and the first switch is open, and calculate the first insulation impedance of the positive electrode of the battery pack to the metal plate and / or the second insulation impedance of the negative electrode of the battery pack to the metal plate based on the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the third resistor, the resistance value of the fourth resistor and the total voltage of the battery pack.

[0024] Optionally, the battery pack includes: a plurality of battery modules connected in series, the metal plates of each battery module are connected by a wiring harness, and the metal plates of each battery module are connected to the insulation detection circuit through the wiring harness;

[0025] The insulation detection circuit is specifically used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate of each battery module.

[0026] Optionally, the battery pack includes: a plurality of battery modules connected in series, and the insulation detection circuit includes: respective third switches corresponding to respective battery modules, and the metal plate of each battery module is connected to the third switch corresponding to the battery module;

[0027] The insulation detection circuit is specifically used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate of each battery module when the third switch corresponding to the battery module is closed and the third switches corresponding to other battery modules are opened.

[0028] Optionally, the battery cell is arranged on the metal plate;

[0029] or,

[0030] The battery module further includes: a second insulating sheet; the battery cell is arranged on the second insulating sheet, and the second insulating sheet is arranged on the metal plate.

[0031] Optionally, the energy storage system further includes: a main circuit switch, an isolated communication integrated circuit and a micro control unit, wherein the main circuit switch is arranged on a DC bus of the battery pack, and the insulation detection circuit is communicatively connected with the micro control unit via the isolated communication integrated circuit;

[0032] The insulation detection circuit is further used to send the insulation impedance to the micro control unit;

[0033] The micro control unit is used to determine whether the insulation impedance is less than a preset threshold value, and when the determination result is yes, determine that the battery cell has leaked, and control the main circuit switch to be disconnected.

[0034] Optionally, the energy storage system further comprises: a main circuit switch, wherein the main circuit switch is arranged on a DC bus of the battery pack;

[0035] The insulation detection circuit is also used to determine whether the insulation impedance is less than a preset threshold value, and when the determination result is yes, determine that the battery cell has leaked, and control the main circuit switch to disconnect.

[0036] Beneficial effects of the embodiments of the present invention:

[0037] In the solution provided by the embodiment of the present invention, the energy storage system includes: an insulation detection circuit and a battery pack composed of at least one battery module; the battery module includes: a battery cell, a metal plate, a first insulating sheet and a metal shell, wherein the battery cell is arranged in the metal plate, the metal plate is arranged on the first insulating sheet, and the first insulating sheet is arranged on the metal shell; the insulation detection circuit is connected to the metal plate, and is used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate, wherein the insulation impedance is used to detect whether the battery cell is leaking. Because the battery cell is arranged inside the metal plate, when the battery cell leaks, the electrolyte will naturally flow to the gap between the battery cell and the metal plate, which will cause the insulation impedance between the leaking battery cell and the metal plate to decrease significantly. On this basis, considering that the positive and negative electrodes of the battery pack are connected to the battery cell, therefore, by detecting the insulation impedance of the positive and / or negative electrodes of the battery pack to the metal plate, it can be determined whether the battery cell is leaking, thereby achieving effective detection of battery cell leakage and ensuring the safety of the energy storage system.

[0038] Of course, it is not necessary to achieve all of the advantages described above at the same time to implement any product or method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0040] Figure 1 A schematic diagram of an energy storage system provided in an embodiment of the present application;

[0041] Figure 2 Based on Figure 1 A schematic diagram of a battery module of the illustrated embodiment;

[0042] Figure 3 Based on Figure 1 A schematic diagram of an insulation detection circuit of the illustrated embodiment;

[0043] Figure 4 Based on Figure 3 A schematic diagram of a circuit structure in an energy storage system of the illustrated embodiment;

[0044] Figure 5a Based on Figure 4 A schematic diagram of the current flow of the illustrated embodiment;

[0045] Figure 5b Based on Figure 4 Another schematic diagram of the current flow of the illustrated embodiment;

[0046] Figure 5c Based on Figure 4 Another schematic diagram of the current flow of the illustrated embodiment;

[0047] Figure 6 Based on Figure 1 A schematic diagram of another insulation detection circuit of the illustrated embodiment;

[0048] Figure 7 Based on Figure 6 A schematic diagram of a circuit structure in an energy storage system of the illustrated embodiment;

[0049] Figure 8a Based on Figure 7 A schematic diagram of the current flow of the illustrated embodiment;

[0050] Figure 8b Based on Figure 7 Another schematic diagram of the current flow of the illustrated embodiment;

[0051] Figure 9a Based on Figure 3 A specific schematic diagram of the energy storage system of the illustrated embodiment;

[0052] Figure 9b Based on Figure 6 A specific schematic diagram of the energy storage system of the illustrated embodiment;

[0053] Fig.10a Based on Figure 3 Another specific schematic diagram of the energy storage system of the illustrated embodiment;

[0054] Fig.10b Based on Figure 6 Another specific schematic diagram of the energy storage system of the illustrated embodiment;

[0055] Fig.11 Based on Figure 1A specific schematic diagram of the energy storage system of the illustrated embodiment;

[0056] Fig.12 Based on Figure 1 Another specific schematic diagram of the energy storage system of the illustrated embodiment. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field based on this application belong to the scope of protection of the present invention.

[0058] In order to detect battery cell leakage and ensure the safety of the energy storage system, an embodiment of the present application provides an energy storage system including an insulation detection circuit and a battery pack composed of at least one battery module. The energy storage system provided in the embodiment of the present application is introduced below.

[0059] refer to Figure 1 , Figure 1 A schematic diagram of an energy storage system provided in an embodiment of the present application, the energy storage system may include an insulation detection circuit 10 and a battery pack composed of at least one battery module 20. It should be noted that: Figure 1 The bold line segment in the figure represents the DC bus of the battery pack. Figure 1 Only the case where the battery module 20 includes one battery module 20 is shown. In addition, the battery module 20 may also include multiple battery modules. The present application does not limit the specific number of the battery modules 20.

[0060] For the battery module 20:

[0061] The battery module 20 may include: a battery cell 201, a metal plate 202, a first insulating sheet 203 and a metal shell 204. It should be noted that: Figure 1 The battery cell 201 , metal plate 202 , first insulating sheet 203 and metal shell 204 shown in the figure are only for illustrating the composition of the battery module 20 , and do not constitute a specific limitation on the arrangement method and positional relationship between the battery cell 201 , metal plate 202 , first insulating sheet 203 and metal shell 204 .

[0062] The battery cell 201 can be disposed in the metal plate 202 in the following two ways but is not limited thereto.

[0063] In the first method, the battery cell 201 can be directly set on the metal plate 202. In this way, when the battery cell 201 leaks, the electrolyte will flow directly to the metal plate 202, so that a conductive path is formed between the battery cell 201 and the metal plate 202, thereby reducing the insulation resistance between the battery cell 201 and the metal plate 202.

[0064] In the second method, if Figure 2 As shown, the battery module 20 may further include a second insulating sheet 205, on which the battery cell 201 is disposed, and the second insulating sheet 205 is disposed on the metal plate 202. In this way, when leakage occurs in the battery cell 201, the electrolyte will flow onto the second insulating sheet 205, and the insulation resistance of the second insulating sheet 205 will gradually decrease due to being soaked in the electrolyte, thereby also causing the insulation resistance between the battery cell 201 and the metal plate 202 to decrease. At the same time, the second insulating sheet 205, as a barrier between the battery cell 201 and the metal plate 202, can also prevent or delay the electrolyte from directly contacting the metal plate 202, thereby preventing corrosion of the metal plate 202 or avoiding problems such as short circuits.

[0065] Among them, the above-mentioned “battery cell 201 is arranged in the metal plate 202” can be that the metal plate 202 wraps the entire battery cell 201, or the metal plate 202 is only arranged under the battery cell 201. No specific limitation is made here. It only needs to ensure that when the battery cell 201 leaks, the electrolyte can naturally flow to the gap between the battery cell 201 and the metal plate 202.

[0066] Furthermore, because the metal shell 204 of the battery module 20 is often exposed to the external environment and is a part that can be directly touched by personnel, once it is charged, there is a great safety hazard. Based on this, the metal plate 202 can be further set on the first insulating sheet 203, and then the first insulating sheet 203 can be set on the metal shell 204. In this way, even if the battery cell 201 leaks and makes the metal plate 202 charged, the metal shell 204 of the battery module 20 can remain uncharged by virtue of the insulating isolation effect of the first insulating sheet 203, effectively avoiding the safety hazards that may be caused by the charged metal shell 204, and greatly improving the overall safety and reliability of the battery module 20.

[0067] For the insulation detection circuit 10:

[0068] When the battery cell 201 is normal and does not leak, the electrolyte is sealed inside the battery cell 201 because the battery cell 201 has a complete structure, and no conductive path is formed between the battery cell 201 and the metal plate 202. In this state, the insulation impedance between the positive and negative electrodes of the battery pack and the metal plate 202 mainly depends on the insulation impedance between the battery cell 201 and the metal plate 202, and the insulation impedance at this time is within the normal range. When the battery cell 201 leaks, the leaked electrolyte will flow into the gap between the battery cell 201 and the metal plate 202, and the electrolyte is conductive, which breaks the relatively stable insulation state between the metal plate 202 and the positive and negative electrodes of the battery pack.

[0069] Therefore, the insulation detection circuit 10 can be connected to the metal plate 202, and it can also be connected to the positive and negative electrodes of the battery pack. In this way, the insulation detection circuit 10 can detect the insulation impedance of the positive and / or negative electrodes of the battery pack to the metal plate 202 based on the above connection relationship, and the insulation impedance can be used to reflect whether the battery cell 201 has leakage. The specific structure of the insulation detection circuit 10 and the specific method of detecting the insulation impedance will be described in detail in the subsequent embodiments, and will not be repeated here.

[0070] In the solution provided by the embodiment of the present application, because the battery cell is arranged inside the metal plate, when the battery cell leaks, the electrolyte will naturally flow to the gap between the battery cell and the metal plate, which will cause the insulation impedance between the leaking battery cell and the metal plate to drop significantly. On this basis, considering that the positive and negative electrodes of the battery pack are connected to the battery cell, therefore, by detecting the insulation impedance of the positive and / or negative electrodes of the battery pack to the metal plate, it is possible to determine whether the battery cell is leaking, thereby achieving effective detection of battery cell leakage and ensuring the safety of the energy storage system.

[0071] As an implementation method of the present application, Figure 3 As shown, the insulation detection circuit 10 may include: a first resistor 101, a second resistor 102, a third resistor 103, a fourth resistor 104, a first switch 105, a second switch 106, a third switch 107 and a control unit 108, wherein the connection relationship between each resistor, switch and a battery pack composed of at least one battery module 20 is as follows:

[0072] A first end of the first resistor 101 is connected to the positive electrode of the battery pack, a second end of the first resistor 101 is connected to the first end of the first switch 105, and a second end of the first switch 105 is connected to a first end of the third switch 107; a first end of the second resistor 102 is connected to the positive electrode of the battery pack, and a second end of the second resistor 102 is connected to a first end of the third switch 107; a first end of the third resistor 103 is connected to the negative electrode of the battery pack, a second end of the third resistor 103 is connected to a first end of the second switch 106, and a second end of the second switch 106 is connected to a first end of the third switch 107; a first end of the fourth resistor 104 is connected to the negative electrode of the battery pack, a second end of the fourth resistor 104 is connected to a first end of the third switch 107; a second end of the third switch 107 is connected to the metal plate 202.

[0073] Based on the above connection relationship, assuming Figure 3 The upper part of the battery pack is the positive electrode, and the lower part is the negative electrode. The first insulation impedance of the positive electrode of the battery pack to the metal plate 202 is represented by the fifth resistor 401, and the second insulation impedance of the negative electrode of the battery pack to the metal plate 202 is represented by the sixth resistor 402. At this time, the circuit structure in the energy storage system can be as follows: Figure 4 It should be noted that the fifth resistor 401 and the sixth resistor 402 are not connected.

[0074] Based on the above circuit structure, the following can be controlled in sequence: "the first switch 105 and the third switch 107 are closed, and the second switch 106 is opened", "the second switch 106 and the third switch 107 are closed, and the first switch 105 is opened", and "the first switch 105, the second switch 106, and the third switch 107 are all opened". Then, based on the voltage change in the circuit under the above three switch control modes, the insulation impedance of the positive electrode and / or the negative electrode of the battery pack to the metal plate 202 is determined. Specifically:

[0075] When the first switch 105, the second switch 106 and the third switch 107 are all disconnected, the direction of the current flowing from the positive electrode of the battery pack to the negative electrode of the battery pack in the energy storage system is as follows: Figure 5a As shown, at this time, because the resistance values ​​of the second resistor 102 and the fourth resistor 104 are both known, the control unit 108 can determine the total voltage of the battery pack by detecting the voltage of the fourth resistor 104 .

[0076] When the first switch 105 and the third switch 107 are closed and the second switch 106 is open, the direction of the current flowing from the positive electrode of the battery pack to the negative electrode of the battery pack in the energy storage system is as follows: Figure 5bAs shown, at this time, a voltage or current equation can be established according to the voltage of the fourth resistor 104, the total voltage of the battery pack and the parallel and series relationship between the various circuits. In the established equation, the resistance values ​​of the first resistor 101, the second resistor 102, the fourth resistor 104 and the total voltage of the battery pack are all known, and only the fifth resistor 401 and the sixth resistor 402 are unknown.

[0077] When the second switch 106 and the third switch 107 are closed and the first switch 105 is open, the direction of the current flowing from the positive electrode of the battery pack to the negative electrode of the battery pack in the energy storage system is as follows: Figure 5c As shown, at this time, a voltage or current equation can be established according to the voltage of the fourth resistor 104, the total voltage of the battery pack and the parallel and series relationship between the various circuits. In the established equation, the resistance values ​​of the second resistor 102, the third resistor 103, the fourth resistor 104 and the total voltage of the battery pack are all known, and only the fifth resistor 401 and the sixth resistor 402 are unknown.

[0078] By combining the equation established when "the first switch 105 and the third switch 107 are closed, and the second switch 106 is open" with the equation established when "the second switch 106 and the third switch 107 are closed, and the first switch 105 is open", the resistance values ​​of the fifth resistor 401 and the sixth resistor 402 can be solved, that is, the insulation impedance of the positive and negative electrodes of the battery pack to the metal plate 202 can be determined.

[0079] It should be noted here that when detecting whether there is a leakage, the control unit 108 can only calculate the insulation resistance of the positive electrode of the battery pack to the metal plate 202, or only calculate the insulation resistance of the negative electrode of the battery pack to the metal plate 202, or calculate the insulation resistance of both the positive and negative electrodes of the battery pack to the metal plate 202, without specific limitation here.

[0080] In the solution provided by the embodiment of the present application, on the one hand, different switches are controlled to be closed or opened in sequence, and voltage or current equations are established based on the current flow direction and the corresponding parallel-series relationship under different circumstances, thereby determining the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate. On the other hand, in the above circuit structure, when all switches are opened, the control unit can also determine the total voltage of the battery pack through the voltage of the third resistor, thereby realizing effective detection of the total voltage of the battery pack.

[0081] As an implementation method of the present application, Figure 6As shown, the insulation detection circuit 10 may include: a first resistor 101, a third resistor 103, a fourth resistor 104, a first switch 105, a second switch 106 and a control unit 108, and the energy storage system may also include: a voltage detection device 30, wherein the connection relationship between each resistor, switch, voltage detection device 30 and a battery pack composed of at least one battery module 20 is as follows:

[0082] A first end of the first resistor 101 is connected to the positive electrode of the battery pack, a second end of the first resistor 101 is connected to the first end of the first switch 105, and a second end of the first switch 105 is connected to the metal plate 202; a first end of the third resistor 103 is connected to the negative electrode of the battery pack, a second end of the third resistor 103 is connected to the first end of the second switch 106, and a second end of the second switch 106 is connected to the metal plate 202; a first end of the fourth resistor 104 is connected to the negative electrode of the battery pack, and a second end of the fourth resistor 104 is connected to the metal plate 202; a voltage detection device 30 is connected to the positive and negative electrodes of the battery pack for detecting the total voltage of the battery pack.

[0083] Based on the above connection relationship, assuming Figure 6 The upper part of the battery pack is the positive electrode, and the lower part is the negative electrode. The first insulation impedance of the positive electrode of the battery pack to the metal plate 202 is represented by the fifth resistor 701, and the second insulation impedance of the negative electrode of the battery pack to the metal plate 202 is represented by the sixth resistor 702. At this time, the circuit structure in the energy storage system can be as follows: Figure 7 It should be noted that the fifth resistor 701 and the sixth resistor 702 are not connected.

[0084] Based on the above circuit structure, the "first switch 105 is closed, the second switch 106 is opened" and "the second switch 106 is closed, the first switch 105 is opened" can be controlled in sequence. Then, based on the voltage change in the circuit under the above two switch control modes and the total voltage of the battery pack detected by the voltage detection device 30, the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate 202 is determined. Specifically:

[0085] When the first switch 105 is closed and the second switch 106 is open, the direction of the current flowing from the positive electrode of the battery pack to the negative electrode of the battery pack in the energy storage system is as follows: Figure 8a As shown, at this time, a voltage or current equation can be established based on the voltage of the fourth resistor 104, the total voltage of the battery pack and the parallel and series relationship between the various circuits. In the established equation, the resistance values ​​of the first resistor 101 and the fourth resistor 104 and the total voltage of the battery pack are all known, and only the fifth resistor 701 and the sixth resistor 702 are unknown.

[0086] When the second switch 106 is closed and the first switch 105 is open, the direction of the current flowing from the positive electrode of the battery pack to the negative electrode of the battery pack in the energy storage system is as follows: Figure 8b As shown, at this time, a voltage or current equation can be established based on the voltage of the fourth resistor 104, the total voltage of the battery pack and the parallel and series relationship between the various circuits. In the established equation, the resistance values ​​of the third resistor 103, the fourth resistor 104 and the total voltage of the battery pack are all known, and only the fifth resistor 701 and the sixth resistor 702 are unknown.

[0087] By combining the equation established when "the first switch 105 is closed and the second switch 106 is open" with the equation established when "the second switch 106 is closed and the first switch 105 is open", the resistance values ​​of the fifth resistor 701 and the sixth resistor 702 can be solved, that is, the insulation impedance of the positive and negative electrodes of the battery pack to the metal plate 202 can be determined.

[0088] It should be noted here that when detecting whether there is a leakage, the control unit 108 can only calculate the insulation resistance of the positive electrode of the battery pack to the metal plate 202, or only calculate the insulation resistance of the negative electrode of the battery pack to the metal plate 202, or calculate the insulation resistance of both the positive and negative electrodes of the battery pack to the metal plate 202, without specific limitation here.

[0089] In the solution provided in the embodiment of the present application, on the one hand, different switches are controlled to be closed or opened in sequence, and voltage or current equations are established based on the current flow direction and the corresponding parallel-series relationship under different circumstances, so as to determine the insulation resistance of the positive electrode and / or negative electrode of the battery pack to the metal plate. Figure 3 The insulation detection circuit shown reduces the third switch and the second resistor, further simplifying the structure of the insulation detection circuit.

[0090] As an implementation of an embodiment of the present application, the above-mentioned insulation detection circuit 10 may also include a seventh resistor, the first end of the fourth resistor 104 is connected to the first end of the seventh resistor, and the second end of the seventh resistor is connected to the negative electrode of the battery pack, so that the fourth resistor 104 can be voltage-divided by the seventh resistor to avoid the voltage of the fourth resistor 104 being too high.

[0091] As an implementation of an embodiment of the present application, when the battery pack includes multiple battery modules 20 connected in series, the metal plates 202 of each battery module 20 can be connected by a wiring harness, and the metal plates 202 of each battery module 20 are connected to the insulation detection circuit 10 through the wiring harness.

[0092] The specific structure of the insulation detection circuit 10 is as follows Figure 3 As shown, the connection relationship between the metal plate 202 and the insulation detection circuit 10 can be as follows Figure 9ashown.

[0093] The specific structure of the insulation detection circuit 10 is as follows Figure 6 As shown, the connection relationship between the metal plate 202 and the insulation detection circuit 10 can be as follows: Figure 9b shown.

[0094] Based on the connection method between the metal plate 202 and the insulation detection circuit 10 , the insulation detection circuit 10 can perform overall detection on each electromagnetic module, that is, detect the insulation impedance of the positive and / or negative poles of the battery pack to the metal plate 202 of each battery module 20 .

[0095] In the solution provided in the embodiment of the present application, by connecting the metal plates of each battery module with a wiring harness and connecting them as a whole to the insulation detection circuit, multiple series-connected battery modules can be detected for leakage at one time, without the need to perform tedious leakage detection operations on each battery module separately, thereby greatly reducing the detection time and the complexity of the detection process, and significantly improving the efficiency of leakage detection. Especially in the application scenario of large-scale battery packs, it can effectively improve the operating efficiency and economy of the entire energy storage system.

[0096] As an implementation of an embodiment of the present application, when the battery pack includes multiple battery modules 20 connected in series, the insulation detection circuit 10 may include: each third switch 107 corresponding to each battery module 20, and the metal plate 202 of each battery module 20 is connected to the third switch 107 corresponding to the battery module 20.

[0097] The specific structure of the insulation detection circuit 10 is as follows: Figure 3 When multiple third switches 107 are added to the insulation detection circuit shown in FIG. 1 , the connection relationship between the metal plate 202 and the insulation detection circuit 10 can be as follows: Fig.10a shown.

[0098] The specific structure of the insulation detection circuit 10 is as follows: Figure 6 When multiple third switches 107 are added to the insulation detection circuit shown in FIG. 1 , the connection relationship between the metal plate 202 and the insulation detection circuit 10 can be as follows: Fig.10b shown.

[0099] Based on the connection method between the above-mentioned metal plate 202 and the insulation detection circuit 10, the insulation detection circuit 10 can detect each electromagnetic module separately, that is, for each battery module 20, the insulation detection circuit 10 can detect the insulation impedance of the positive and / or negative electrodes of the battery pack to the metal plate 202 of the battery module 20 when the third switch 107 corresponding to the battery module 20 is closed and the third switches 107 corresponding to other battery modules 20 are disconnected.

[0100] In the solution provided in the embodiment of the present application, by setting a corresponding third switch for each battery module, each battery module can be specifically tested for leakage. The interference of other normal battery modules on the test results is effectively avoided, and the battery module that may leak is accurately located, which greatly improves the accuracy and flexibility of the test. In terms of troubleshooting, because each battery module can be tested separately, it is possible to quickly determine which battery module is leaking, which greatly shortens the scope and time of troubleshooting, is conducive to quickly taking repair measures, reduces the downtime of the entire battery pack due to the faulty module, and improves the overall availability and reliability of the battery pack.

[0101] As an implementation method of the present application, Fig.11 As shown, the energy storage system may further include: a main circuit switch 40, an isolated communication integrated circuit 50 and a micro control unit 60. The main circuit switch 40 is arranged on the DC bus of the battery pack, and the insulation detection circuit 10 is connected to the micro control unit 60 through the isolated communication integrated circuit 50.

[0102] After detecting the insulation impedance of the positive electrode and / or the negative electrode of the battery pack to the metal plate 202 , the insulation detection circuit 10 can send the insulation impedance to the micro control unit 60 through the isolated communication integrated circuit 50 .

[0103] After receiving the insulation impedance sent by the insulation detection circuit 10, the micro control unit 60 can determine whether the insulation impedance is less than a preset threshold value. If the determination result is yes, it means that the battery cell 201 has leaked, and at this time, the micro control unit 60 can control the main circuit switch 40 to be disconnected. If the determination result is no, it means that the battery cell 201 is normal, and at this time, the micro control unit 60 may not perform any operation.

[0104] In the solution provided by the embodiment of the present application, on the one hand, when the microcontroller unit determines that the insulation impedance is less than the preset threshold, it can control the main circuit switch set on the DC bus of the battery pack to disconnect, realizing an automated fault detection and emergency handling mechanism, thereby effectively preventing the battery pack fault from further expanding and ensuring the basic safe operation of the entire energy storage system. On the other hand, the insulation detection circuit and the microcontroller unit are connected for communication through an isolated communication integrated circuit. This isolated communication method can avoid electrical interference from being transmitted between the two, ensure the accuracy and stability of data transmission, and enable the insulation impedance data obtained by the insulation detection circuit to be accurately and correctly delivered to the microcontroller unit.

[0105] As an implementation method of the present application, Fig.12 As shown, the energy storage system may further include: a main circuit switch 40, which is arranged on the DC bus of the battery pack.

[0106] After detecting the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate 202, the insulation detection circuit 10 can determine by itself whether the insulation impedance is less than a preset threshold value. If the judgment result is yes, it means that the battery cell 201 has leaked, and at this time, the insulation detection circuit 10 can control the main circuit switch 40 to be disconnected. If the judgment result is no, it means that the battery cell 201 is normal, and at this time, the insulation detection circuit 10 may not perform any operation.

[0107] In the solution provided in the embodiment of the present application, when the insulation detection circuit determines that the insulation impedance is less than a preset threshold, it can control the main circuit switch set on the DC bus of the battery pack to disconnect, thereby realizing an automated fault detection and emergency handling mechanism, thereby effectively preventing the battery pack fault from further expanding and ensuring the basic safe operation of the entire energy storage system.

[0108] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive Solid State Disk (SSD)), etc.

[0109] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0110] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. An energy storage system, characterized in that: The energy storage system comprises: an insulation detection circuit and a battery pack consisting of at least one battery module; The battery module comprises: a battery cell, a metal plate, a first insulating sheet and a metal shell, wherein the battery cell is arranged in the metal plate, the metal plate is arranged on the first insulating sheet, and the first insulating sheet is arranged on the metal shell; The insulation detection circuit is connected to the metal plate and is used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate, wherein the insulation impedance is used to detect whether the battery cell is leaking.

2. The system according to claim 1, characterized in that The insulation detection circuit comprises: a first resistor, a second resistor, a third resistor, a fourth resistor, a first switch, a second switch, a third switch and a control unit; The first end of the first resistor is connected to the positive electrode of the battery pack, the second end of the first resistor is connected to the first end of the first switch, and the second end of the first switch is connected to the first end of the third switch; A first end of the second resistor is connected to the positive electrode of the battery pack, and a second end of the second resistor is connected to the first end of the third switch; The first end of the third resistor is connected to the negative electrode of the battery pack, the second end of the third resistor is connected to the first end of the second switch, and the second end of the second switch is connected to the first end of the third switch; A first end of the fourth resistor is connected to the negative electrode of the battery pack, and a second end of the fourth resistor is connected to the first end of the third switch; The second end of the third switch is connected to the metal plate; The control unit is used to detect the voltage of the fourth resistor, and determine the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate according to the voltage of the fourth resistor; The control unit is further configured to detect the total voltage of the battery pack when the first switch, the second switch and the third switch are all disconnected.

3. The system according to claim 2, characterized in that The control unit is specifically used to detect the voltage of the fourth resistor to obtain a first voltage when the first switch and the third switch are closed and the second switch is opened, and to detect the voltage of the fourth resistor to obtain a second voltage when the second switch and the third switch are closed and the first switch is opened, and to calculate the first insulation impedance of the positive electrode of the battery pack to the metal plate and / or the second insulation impedance of the negative electrode of the battery pack to the metal plate based on the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the second resistor, the resistance value of the third resistor, the resistance value of the fourth resistor and the total voltage of the battery pack.

4. The system according to claim 1, characterized in that The insulation detection circuit includes: a first resistor, a third resistor, a fourth resistor, a first switch, a second switch and a control unit, and the energy storage system also includes: a voltage detection device; A first end of the first resistor is connected to the positive electrode of the battery pack, a second end of the first resistor is connected to a first end of the first switch, and a second end of the first switch is connected to the metal plate; A first end of the third resistor is connected to the negative electrode of the battery pack, a second end of the third resistor is connected to a first end of the second switch, and a second end of the second switch is connected to the metal plate; A first end of the fourth resistor is connected to the negative electrode of the battery pack, and a second end of the fourth resistor is connected to the metal plate; The control unit is used to detect the voltage of the fourth resistor, and determine the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate according to the voltage of the fourth resistor; The voltage detection device is used to detect the total voltage of the battery pack.

5. The system according to claim 4, characterized in that The control unit is specifically used to detect the voltage of the fourth resistor to obtain a first voltage when the first switch is closed and the second switch is opened, and to detect the voltage of the fourth resistor to obtain a second voltage when the second switch is closed and the first switch is opened, and to calculate the first insulation impedance of the positive electrode of the battery pack to the metal plate and / or the second insulation impedance of the negative electrode of the battery pack to the metal plate based on the first voltage, the second voltage, the resistance value of the first resistor, the resistance value of the third resistor, the resistance value of the fourth resistor and the total voltage of the battery pack.

6. The system according to any one of claims 1 to 5, characterized in that: The battery pack comprises: a plurality of battery modules connected in series, wherein the metal plates of the battery modules are connected by a wiring harness, and the metal plates of the battery modules are connected to the insulation detection circuit through the wiring harness; The insulation detection circuit is specifically used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate of each battery module.

7. The system according to any one of claims 1 to 5, characterized in that: The battery pack includes: a plurality of battery modules connected in series, the insulation detection circuit includes: respective third switches corresponding to respective battery modules, the metal plate of each battery module being connected to the third switch corresponding to the battery module; The insulation detection circuit is specifically used to detect the insulation impedance of the positive electrode and / or negative electrode of the battery pack to the metal plate of each battery module when the third switch corresponding to the battery module is closed and the third switches corresponding to other battery modules are opened.

8. The system according to any one of claims 1 to 5, characterized in that: The battery cell is arranged on the metal plate; or, The battery module further includes: a second insulating sheet; the battery cell is arranged on the second insulating sheet, and the second insulating sheet is arranged on the metal plate.

9. The system according to any one of claims 1 to 5, characterized in that: The energy storage system further comprises: a main circuit switch, an isolated communication integrated circuit and a micro control unit, wherein the main circuit switch is arranged on the DC bus of the battery pack, and the insulation detection circuit is connected to the micro control unit through the isolated communication integrated circuit; The insulation detection circuit is further used to send the insulation impedance to the micro control unit; The micro control unit is used to determine whether the insulation impedance is less than a preset threshold value, and when the determination result is yes, determine that the battery cell has leaked, and control the main circuit switch to be disconnected.

10. The system according to any one of claims 1 to 5, characterized in that: The energy storage system further comprises: a main circuit switch, wherein the main circuit switch is arranged on a DC bus of the battery pack; The insulation detection circuit is also used to determine whether the insulation impedance is less than a preset threshold value, and when the determination result is yes, determine that the battery cell has leaked, and control the main circuit switch to disconnect.

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