Battery module, battery pack and energy storage system

Abstract

A battery module (600), a battery pack (1), and an energy storage system. The battery module (600) comprises a first protection unit (610), a first battery cell and a second battery cell; the first protection unit (610) comprises a first breaking device (613), a first detection unit (612) and a first controller (611); the first battery cell and the second battery cell are connected in series. The first breaking device (613) is connected in series between the first battery cell and the second battery cell. The first detection unit (612) is used for detecting first state information, the first state information being used for indicating the state of the battery module (600). When the first state information indicates that the battery module (600) is abnormal, the first controller (611) is used for controlling the first breaking device (613) to be cut off.

Description

Battery modules, battery packs and energy storage systems

[0001] This application claims priority to Chinese Patent Application No. 202311683851.6, filed with the State Intellectual Property Office of China on December 8, 2023, entitled “Battery Module, Battery Pack and Energy Storage System”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to battery modules, battery packs, and energy storage systems. Background Technology

[0003] Battery packs are widely used in energy storage systems and electric vehicles. As a carrier of electrical energy, battery packs are susceptible to safety malfunctions during manufacturing, transportation, storage, installation, and operation. These malfunctions fall into two main categories: manufacturing defects leading to cell leakage or thermal runaway, and environmental abuse such as overvoltage, overcurrent, or overtemperature, ultimately posing safety risks to the battery pack. Therefore, system design must incorporate protection measures for the battery pack. Summary of the Invention

[0004] This application provides a battery module, battery pack, and energy storage system that can effectively reduce the risk of high-voltage breakdown of cell insulation between cells.

[0005] In a first aspect, this application provides a battery module, which includes a first protection unit, a first battery cell, and a second battery cell; the first protection unit includes a first disconnecting device, a first detection unit, and a first controller; the first battery cell and the second battery cell are connected in series; the first disconnecting device is connected in series between the first battery cell and the second battery cell; the first detection unit is used to detect first status information, which is used to indicate the status of the battery module; the first controller is used to control the first disconnecting device to disconnect when the first status information indicates that the battery module is abnormal.

[0006] Optionally, the first disconnecting device mentioned above can be an explosive fuse, contactor, relay, or semiconductor switch, etc., and this application does not limit it.

[0007] In this solution, by setting up a protection unit in the battery module and connecting the disconnecting device in series between the cells, the disconnecting device can be quickly disconnected when the cells in the battery module experience abnormalities (such as overcurrent, overtemperature, or leakage). This effectively reduces the risk of high voltage breakdown of the cell insulation between the cells in the battery module, thus protecting the battery module.

[0008] In one possible implementation, the aforementioned first cell and the aforementioned second cell belong to the first cell group of the aforementioned battery module; the aforementioned battery module also includes a second cell group, which includes a third cell and a fourth cell; the total voltage of the aforementioned first cell group is less than or equal to the insulation withstand voltage of the aforementioned first cell or the aforementioned second cell, and the total voltage of the aforementioned second cell group is less than or equal to the insulation withstand voltage of the aforementioned third cell or the aforementioned fourth cell; the aforementioned first status information is used to indicate the status of the aforementioned first cell group; the aforementioned first controller is used to control the aforementioned first disconnecting device to disconnect when the aforementioned first status information indicates that the aforementioned first cell group is abnormal; the aforementioned battery module also includes a second protection unit; the aforementioned second protection unit includes a second disconnecting device, a second detection unit, and a second controller; the aforementioned second disconnecting device is connected in series between the aforementioned third cell and the aforementioned fourth cell; the aforementioned second detection unit is used to detect second status information; the aforementioned second status information is used to indicate the status of the aforementioned second cell group; the aforementioned second controller is used to control the aforementioned second disconnecting device to disconnect when the aforementioned second status information indicates that the aforementioned second cell group is abnormal.

[0009] In this design, multiple protection units can be set up in the battery module, with different protection units protecting different groups of cells. Furthermore, the total voltage of each cell group does not exceed the insulation withstand voltage of the cells within that group. This grouping design ensures that the voltage applied to the cell by external pathways created by leakage or other factors within a group does not exceed the cell's insulation voltage, thus reducing the voltage applied to the cell by these external pathways. In addition, this grouping design allows for comprehensive and timely detection of anomalies; regardless of which cell in the battery module malfunctions, a corresponding protection unit can detect it and take protective measures, effectively reducing the risk of cell breakdown.

[0010] In another possible implementation, the aforementioned first cell belongs to a first cell group, and the aforementioned second cell belongs to a second cell group; the aforementioned battery module also includes a third cell group, which includes a fifth cell; the total voltage of the aforementioned first cell group is less than or equal to the insulation withstand voltage of the aforementioned first cell, the total voltage of the aforementioned second cell group is less than or equal to the insulation withstand voltage of the aforementioned second cell, and the total voltage of the aforementioned third cell group is less than or equal to the insulation withstand voltage of the aforementioned fifth cell; the aforementioned first status information is used to indicate the status of the aforementioned first cell group; the aforementioned first controller is used to control the aforementioned first disconnecting device to disconnect when the aforementioned first status information indicates that the aforementioned first cell group is abnormal; the aforementioned battery module also includes a third protection unit, which includes a third disconnecting device, a third detection unit, and a third controller; the aforementioned third disconnecting device is connected in series between the aforementioned second cell and the aforementioned fifth cell; the aforementioned third detection unit is used to detect the third status information; the aforementioned third status information is used to indicate the status of the aforementioned second cell group; the aforementioned third controller is used to control the aforementioned third disconnecting device to disconnect when the aforementioned third status information indicates that the aforementioned second cell group is abnormal.

[0011] In this design, protection units can be placed between cell groups. Similarly, this grouping design ensures that the voltage applied to the cell by external pathways created by leakage or other factors within the group does not exceed the cell's insulation voltage, thus reducing the voltage applied to the cell by these external pathways. Furthermore, this grouping design allows for comprehensive and timely detection of anomalies; regardless of which cell in the battery module malfunctions, a corresponding protection unit can detect it and take protective measures, effectively reducing the risk of cell breakdown.

[0012] In one possible implementation, the first detection unit includes a current detection unit for detecting the current between the first battery cell and the second battery cell; the first controller is used to control the first disconnecting device to disconnect when the current is different from the current at the positive or negative terminal of the battery module; or, the first controller is used to control the first disconnecting device to disconnect when the current is greater than a first threshold.

[0013] In this solution, the disconnecting device can be quickly disconnected when an abnormal current (such as overcurrent) occurs between battery cells, thus protecting the battery module. For example, when an external path forms between battery cells in the battery module due to leakage, this external path forms an additional current loop with the battery cell (referred to as cell A). The current flowing through cell A is the sum of the current in this additional current loop and the current in the main circuit of the battery module (which is also the current at the positive or negative terminal of the battery module). Therefore, by comparing the difference between the current flowing through cell A and the current in the main circuit of the battery module, or by determining whether the current flowing through cell A exceeds a preset threshold, an abnormal current can be detected, allowing for timely protective measures to protect the battery module.

[0014] In one possible implementation, the first detection unit includes a temperature detection unit for detecting the temperature of the first battery cell or the second battery cell; the first controller is used to control the first disconnecting device to disconnect when the temperature of the first battery cell or the second battery cell is greater than a second threshold.

[0015] In this solution, the disconnecting device can be quickly disconnected when an abnormal temperature occurs between battery cells (e.g., overheating), thus protecting the battery module. For example, the temperature of a battery cell is related to the current flowing through it; the higher the current, the higher the cell temperature. Therefore, the current flowing through cell A includes the sum of the current in the additional current loop and the current in the main circuit of the battery module. That is, as the current flowing through cell A increases, the temperature of cell A also increases. Therefore, determining whether the temperature of cell A exceeds a preset threshold can identify an abnormal temperature, allowing for timely protective measures to safeguard the battery module.

[0016] In one possible implementation, the aforementioned first detection unit includes a leakage current detection circuit, which is connected to the grounding wire of the aforementioned battery module and is used to detect the current flowing through the aforementioned grounding wire; the aforementioned first controller is used to control the aforementioned first disconnecting device to disconnect when the current flowing through the aforementioned grounding wire is greater than a third threshold.

[0017] In this solution, the disconnect device can be quickly disconnected when a leakage occurs in the battery module, thus protecting the battery module. For example, if an external path forms an additional current loop, and the grounding wire is connected in this current loop, the current flowing through the grounding wire will also increase. That is, the current in the current loop flows to the grounding wire with a lower potential, causing leakage. Therefore, determining whether the current in the grounding wire exceeds a preset threshold can identify an abnormal leakage, allowing for timely protective measures to protect the battery module.

[0018] In one possible implementation, the aforementioned first detection unit and the aforementioned first controller are powered by one or more cells in the aforementioned battery module. In this solution, the protection unit can be powered by the cells in the battery module to ensure uninterrupted power supply to the protection unit. Even when the battery system is not powered due to storage or transportation, abnormal detection and protection of the battery module can be effectively achieved.

[0019] Secondly, this application provides a battery pack, which includes a battery module as described in any of the first aspects above and a first battery management unit; the first battery management unit is used to collect status information of the battery pack.

[0020] Optionally, the status information of the battery pack may include parameters such as the main circuit current, temperature, or leakage current of the battery pack.

[0021] Optionally, the first battery management unit mentioned above may be a battery management unit (BMU). For example, the BMU may include a module battery management system (mBMS) and corresponding sampling control module, communication module, power supply module, drive control circuit of switch bridge arm, etc., for realizing the status detection and control of battery modules in the battery pack.

[0022] In one possible implementation, the aforementioned battery pack further includes a first auxiliary power supply, which powers the aforementioned first detection unit and the aforementioned first controller in the aforementioned battery module. In this solution, the auxiliary power supply powers the protection unit in the battery module, thereby reducing the impact of power supplied by the battery module on the battery module itself.

[0023] Thirdly, this application provides an energy storage system, which includes the battery pack and the second battery management unit described in the second aspect above; the second battery management unit is connected to the first battery management unit and to the first controller included in the battery module; the second battery management unit is used to receive the status information of the battery pack collected by the first battery management unit; the second battery management unit is also used to notify the first controller to control the first disconnect device to disconnect when the status information indicates that the battery pack is abnormal.

[0024] Optionally, the aforementioned second battery management unit can be a battery control unit (BCU). For example, the BCU can be connected to the BMU in the battery pack via a control bus, enabling real-time information exchange with the battery pack and achieving real-time, unified monitoring of the battery pack. This allows for flexible control of the energy storage system and offers strong applicability.

[0025] In one possible implementation, the aforementioned energy storage system further includes a second auxiliary power supply, which powers the first detection unit and the first controller. In this solution, the auxiliary power supply powers the protection unit in the battery module, thereby reducing the impact of power supplied by the battery module on the battery module itself.

[0026] Fourthly, this application provides a vehicle that includes a battery module as described in any of the first aspects above.

[0027] The beneficial effects of the second to fourth aspects mentioned above can be found in the relevant introduction of the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0028] Figures 1 to 3 are schematic diagrams of existing battery pack structures;

[0029] Figures 4 and 5 are schematic diagrams of the battery pack provided in the embodiments of this application;

[0030] Figures 5A, 5B and 5C show schematic diagrams of the energy storage system provided in the embodiments of this application;

[0031] Figures 6 to 9, 10A and 10B show schematic diagrams of the structure of the battery module provided in the embodiments of this application;

[0032] Figure 11 shows a schematic diagram of the connection between the battery module and the BMS provided in an embodiment of this application;

[0033] Figure 12 is a schematic diagram of the additional current loop generated in the battery module provided in the embodiment of this application;

[0034] Figure 13 is a schematic diagram of an additional current loop between battery packs provided in an embodiment of this application. Detailed Implementation

[0035] In this application embodiment, "multiple" refers to two or more. In this application embodiment, "and / or" is used to describe the association relationship of related objects, indicating three relationships that can exist independently. For example, A and / or B can mean: A exists alone, B exists alone, or A and B exist simultaneously. The description methods used in this application embodiment, such as "at least one of a1, a2, ... and an (or at least one of them)," include the case where any one of a1, a2, ... and an exists alone, as well as the case where any combination of any multiple of a1, a2, ... and an exists alone. Each case can exist alone. For example, the description method of "at least one of a, b, and c" includes the cases where a, b, c, a and b combined, a and c combined, b and c combined, or a, b, and c combined.

[0036] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items with substantially the same function. It should be understood that there is no logical or temporal dependency between "first," "second," and "nth," nor does it limit the quantity or execution order. It should also be understood that although the following description uses the terms "first," "second," etc., to describe various elements, these elements should not be limited by the terms. These terms are merely used to distinguish one element from another. The connections described in the embodiments of this application refer to electrical connections.

[0037] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between the various embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0038] The following describes the embodiments of this application with reference to the accompanying drawings.

[0039] A battery pack may include multiple battery cells. These multiple battery cells may be connected in series. For example, see Figure 1, which illustrates a schematic diagram of a battery pack. Figure 1 shows an example of a battery pack including three battery cells. As can be seen, each battery cell includes a positive (+) terminal and a negative (-) terminal. Battery cell 1, battery cell 2, and battery cell 3 are connected in series in sequence. BAT- represents the negative terminal of the battery pack, and BAT+ represents the positive terminal of the battery pack. It should be understood that Figure 1 is only an example and does not constitute a limitation on the embodiments of this application.

[0040] Battery packs are widely used, but safety risks may exist during manufacturing, transportation, storage, installation, and operation. Therefore, battery pack protection is necessary. One existing protection scheme, as shown in Figure 2, involves placing a fuse at the negative terminal of the battery pack (e.g., Figure 2(a)), a fuse at the positive terminal (e.g., Figure 2(b)), or fuses between cells in a series-connected battery pack (e.g., Figure 2(c)). In other words, the fuses are all located outside the battery pack. In the event of a main power overcurrent or short circuit causing a large current to flow through the fuse, the fuse will actively melt, thus interrupting the large current and preventing the risk of thermal runaway or fire. However, this scheme cannot prevent the risk of thermal runaway or fire caused by high voltage outside the battery pack, leakage of electrolyte within the cells leading to internal leakage, or leakage between multiple battery packs. This is because such leakage does not cause a large current to flow through the fuse, and the fuse will not melt, creating a protection blind spot.

[0041] Another existing protection scheme involves adding a disconnect device outside the battery pack. This disconnect device is controlled by the Battery Management System (BMS), as shown in Figure 3. When the BMS detects an external fault such as overvoltage, overcurrent, or overtemperature, it controls the disconnect device to disconnect, thus cutting off the battery pack's external energy path. This isolates the external fault source or energy source, ensuring the battery pack's safety. However, this scheme cannot provide protection for scenarios where high voltage breaks down the cell insulation within the battery pack, or for scenarios where the BMS is not operational, such as during storage or transportation.

[0042] For example, the aforementioned high-voltage breakdown of the cell insulation refers to a situation where the voltage applied to the cell exceeds the maximum voltage limit that the cell can withstand. In this case, the electrolyte inside the cell will break down, forming a current path through the electrolyte, i.e., the cell insulation is broken down. The maximum voltage limit that the cell can withstand can be called the insulation withstand voltage of the cell. This insulation withstand voltage can be, for example, the insulation withstand voltage between the positive and negative terminals of the cell and the outer casing. To facilitate understanding of the scenario of high-voltage breakdown of the cell insulation, the following description is illustrated with reference to Figures 4 and 5.

[0043] For example, referring to Figure 4, consider the case of a high-voltage breakdown of the cell insulation caused by an external circuit formed between the cells inside the battery pack. As shown in Figure 4, suppose that due to condensation, electrolyte leakage in the cell, coolant (such as the coolant used to heat or cool the battery in a car), or damage to the cell's insulation layer, an external circuit is formed between cell 1 and cell 3 in the battery pack. The current in this external circuit forms a loop through the positive terminal of cell 1 and the negative terminals of cells 2 and 3 in the battery pack. This external circuit is equivalent to a short circuit between cells 1 and 3, and since cell 2 is connected in series between cells 1 and 3, the voltage applied to cells 1 and 3 increases. If this applied voltage exceeds the insulation withstand voltage of cells 1 and 3, it will break down the insulation protection of cells 1 and 3, posing a risk of thermal runaway or even fire to cells 1 and 3. The BMS mainly detects abnormalities on the outside of the battery pack, but it cannot detect insulation breakdown between cells inside the battery pack in a timely manner. Therefore, it cannot cut off the energy channel in time and thus cannot effectively protect the battery pack.

[0044] For example, referring to Figure 5, consider the case of a high-voltage breakdown of the cell insulation caused by an external circuit between two series-connected battery packs. As shown in Figure 5, similarly, assume that due to condensation, electrolyte leakage in the cell, coolant (such as the coolant used to heat or cool the battery in a car), or damage to the cell's insulation layer, an external circuit is formed between cell 1 in battery pack 1 and cell 5 in battery pack 2. The current in this external circuit forms a loop through the positive terminal of cell 1, cells 2 and 3 in battery pack 1, cell 4 in battery pack 2, and the negative terminal of cell 5. This external circuit is equivalent to a short circuit between cells 1 and 5, and since cells 2, 3, and 4 are connected in series between cells 1 and 5, the voltage applied to cells 1 and 5 increases. If the applied voltage exceeds the insulation withstand voltage of cells 1 and 5, it will break down the insulation protection of cells 1 and 5, posing a risk of thermal runaway or even fire. Similarly, the BMS mainly detects anomalies on the outside of the battery pack and cannot detect insulation breakdown between cells within different battery packs in a timely manner. Therefore, it cannot cut off the energy path in time and thus cannot effectively protect the battery pack.

[0045] Based on the above description, in order to better protect the battery pack, this application provides a battery module, a battery pack, and an energy storage system. This effectively reduces the risk of high-voltage breakdown of the cell insulation between cells, thus protecting the battery module, battery pack, or energy storage system. In another possible implementation, it can also provide effective protection in scenarios such as warehousing or transportation where the BMS (Battery Management System) is not working, resulting in the inability to protect the battery module, battery pack, or energy storage system.

[0046] Exemplarily, the energy storage system provided in this application embodiment involves a multi-layer structure. The first layer is called an energy storage system or a battery energy storage system, the second layer is called a battery pack (PACK), and the third layer is called a battery module or an energy storage module. The energy storage system may include one or more battery packs, and the battery pack may include one or more battery modules. In another possible implementation, an intermediate layer may be included between the energy storage system and the battery pack, which may be, for example, an energy storage unit cluster or a battery cluster. Exemplarily, the energy storage system may include one or more battery clusters. A battery cluster may include multiple battery packs. It is understood that different names for the same layer structure have the same meaning in this application embodiment and are all used to refer to this specific layer structure; this application embodiment does not distinguish between them. Furthermore, the layering of the energy storage system described herein is merely an example and does not constitute a limitation on the embodiments of this application. In specific implementations, other layering methods may also be adopted, and this application embodiment does not limit them.

[0047] The energy storage system provided in this application is first described below by way of example. For example, please refer to FIG5A, which shows a possible structural schematic diagram of an energy storage system. As shown in FIG5A, the energy storage system may include multiple battery packs connected in series (n are used as an example in FIG5A, where n is an integer greater than 1). Each battery pack may include a battery module 600 and a first battery management unit 601.

[0048] The energy storage system also includes a second battery management unit 602. The second battery management unit 602 is connected to the first battery management unit 601 in each battery pack.

[0049] In one possible implementation, the energy storage system may also include a direct current (DC) to alternating current (AC) converter, specifically a DC / AC converter 603. This DC / AC converter 603 can be connected to a series-connected battery pack via a DC bus. The DC / AC converter 603 can convert DC power into AC power and exchange energy with the AC power grid.

[0050] For example, a detailed description of the battery module 600 can be found in the following figures 6 to 10B, which will not be elaborated here.

[0051] For example, consider battery pack 1 in an energy storage system. The first battery management unit 601 in battery pack 1 can be used to collect the status information of battery pack 1. The status information of battery pack 1 may include parameters such as the main circuit current (e.g., the current at the positive or negative terminal of battery pack 1), temperature, or leakage current.

[0052] In one implementation, the first battery management unit 601 described above may be, for example, a battery management unit (BMU). Exemplarily, the BMU may include a module battery management system (mBMS) and corresponding sampling control modules, communication modules, power supply modules, drive control circuits for switch arms, etc., to implement state detection within the battery pack.

[0053] For example, the second battery management unit 602 can be connected to the first battery management unit 601 in the battery pack via a control bus. The second battery management unit 602 can interact with the first battery management units 601 in each battery pack in real time to achieve real-time, unified monitoring of each battery pack, thereby enabling flexible control of the energy storage system and providing strong applicability. For instance, the first battery management unit 601 can send the collected battery pack status information to the second battery management unit 602. The second battery management unit 602 can be used to take corresponding protective measures when the status information indicates an abnormality in the battery pack. Specific implementation details can be found in the exemplary description in Figure 11 below, and will not be elaborated here.

[0054] For example, the second battery management unit 602 described above may be a battery control unit (BCU).

[0055] For example, the aforementioned plurality of first battery management units 601 and second battery management units 602 can be collectively referred to as the BMS of an energy storage system. It is understood that, in specific implementations, the BMS in the energy storage system can also be implemented in other ways, and is not limited to the implementation forms described in the embodiments of this application.

[0056] In one possible implementation, as exemplified in Figure 5B, the energy storage system may further include a DC / DC converter 604. The multiple series-connected battery packs can be coupled to a DC bus via the DC / DC converter 604. The DC / DC converter 604 enables flexible energy control of the multiple series-connected battery packs, offering strong applicability. For example, the DC / DC converter 604 can be a bidirectional DC / DC converter, and its circuit topology can be an isolated circuit topology or a non-isolated circuit topology, etc. The circuit topology of this bidirectional DC / DC converter can be a boost circuit, a flying capacitor boost circuit, a flying capacitor multilevel circuit, a three-level boost circuit, a four-switch buck-boost circuit, etc., and can be determined according to the actual application requirements; this application does not impose any limitations on this.

[0057] For example, as shown in FIG5B, the second battery management unit 602 can be integrated into the DC / DC converter 604 to simplify the system structure of the energy storage system. Furthermore, since the multiple series-connected battery packs are typically installed close to the DC / DC converter 604, integrating the second battery management unit 602 into the DC / DC converter 604 facilitates the connection of the control bus. Alternatively, in another possible implementation, the second battery management unit 602 and the DC / DC converter 604 can be configured independently. This application does not impose limitations on this.

[0058] In another possible implementation, for example, the multiple series-connected battery packs can be a battery cluster, as shown in Figure 5C. A cluster control box 605 can be configured for unified control of this battery cluster. The cluster control box 605 can house devices such as cluster-level fuses, cluster-level insulation resistance detectors, and cluster-level switches to achieve cluster-level management and protection. As shown in Figure 5C, the battery cluster can be coupled to the DC bus through the cluster control box 605. For example, the second battery management unit 602 can be integrated into the cluster control box 605 (as shown in Figure 5C) or can be set independently; this embodiment does not limit this.

[0059] It is understood that the structure of the energy storage system shown in Figures 5A to 5C is only an example. In specific implementation, it can be any energy storage structure including the battery module or battery pack provided in the embodiments of this application. The embodiments of this application do not limit the structure of the specific energy storage system.

[0060] In one possible implementation, see Figure 6, which shows a schematic diagram of the structure of a battery module provided in an embodiment of this application.

[0061] The battery module 600 shown in Figure 6 may include a first protection unit 610 and multiple battery cells 620 (Figure 6 shows an example of six battery cells 620). The first protection unit 610 may include a first controller 611, a first detection unit 612, and a first disconnecting device 613. It can be seen that the multiple battery cells 620 and the first disconnecting device 613 are connected in series. For example, the first disconnecting device 613 is connected in series between battery cell 3 and battery cell 4. It is understood that the first disconnecting device 613 can be connected in series between any two adjacent battery cells 620. For example, it can be connected in series between battery cell 2 and battery cell 3, or between battery cell 5 and battery cell 6, etc., and so on, not listed here.

[0062] For example, since the six battery cells 620 are connected in series, it can also be said that the first disconnecting device 613 is connected in series between any two battery cells 1 to 6. For example, the first disconnecting device 613 may be connected in series between battery cell 1 and battery cell 6. Or, the first disconnecting device 613 may be connected in series between battery cell 1 and battery cell 5. Or, the first disconnecting device 613 may be connected in series between battery cell 2 and battery cell 6. Or, the first disconnecting device 613 may be connected in series between battery cell 2 and battery cell 5, and so on.

[0063] For ease of description later, the path connecting the plurality of battery cells 620 and the first disconnecting device 613 in series will be referred to as the first series path. Exemplarily, the first series path can be connected via a power line.

[0064] Exemplary examples show that the first breaking device described above can be, for example, an explosive fuse, a contactor, a relay, or a semiconductor switch, etc., and this application embodiment does not limit this. Exemplary examples show that a semiconductor switch can include, for example, an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET). When a switch is used as the breaking device, the switch can be opened under the control of a control signal, thereby breaking the current path between the battery cells. When an explosive fuse is used as the breaking device, the explosive fuse can be opened under the control of a control signal, thereby breaking the current path between the battery cells. It should be understood that any device capable of breaking according to a control signal can be used as a controllable breaking device in this application embodiment, and the controllable breaking device can be flexibly selected according to actual needs. This application embodiment does not limit the specific implementation of the breaking device.

[0065] The first controller 611 is connected to the first detection unit 612 and the first disconnecting device 613. The first detection unit 612 can detect abnormalities in the first series path and feed the detection results back to the first controller 611. If an abnormality occurs in the first series path, the first controller 611 can control the first disconnecting device 613 to disconnect, thereby cutting off the first series path and protecting the battery module 600. For example, the first detection unit 612 can detect first status information. This first status information indicates the status of the first series path. Specifically, the first status information may include, for example, the current flowing through the cell in the first series path, the temperature of the cell, or the leakage current of the first series path, etc., which are not limited in this embodiment. The first detection unit 612 or the first controller 611 can determine that an abnormality exists in the battery module 600 through the first status information. Detailed analysis is provided later and will not be elaborated here.

[0066] In one possible implementation, the first detection unit 612 may include one or more of the following: a first current detection unit 6121, a first temperature detection unit 6122, and a first leakage current detection unit 6123. Figure 6 illustrates an example including these three units.

[0067] The aforementioned first current detection unit 6121 can be used to detect the current in the aforementioned first series path. For example, as shown in FIG6, the first current detection unit 6121 is connected to the first series path via a signal line, and the current in the first series path is fed back to the first current detection unit 6121 via the connected signal line. It is understood that the position of the first current detection unit 6121 connected to the first series path via the signal line in FIG6 is only an example and does not constitute a limitation on the embodiments of this application. In specific implementation, the first current detection unit 6121 can be connected to any position on the first series path via a signal line. Exemplarily, the first current detection unit 6121 can be any circuit or sensor capable of current detection, etc., and the embodiments of this application do not limit this.

[0068] The aforementioned first temperature detection unit 6122 can be used to detect the temperature of the aforementioned first series path. For example, as shown in FIG6, the first temperature detection unit 6122 is connected to the battery cell 2 in the first series path via a signal line, and the temperature of the battery cell 2 (which can be used to represent the temperature of the first series path) is fed back to the first temperature detection unit 6122 via the connected signal line. It is understood that the battery cell connected to the first temperature detection unit 6122 via the signal line in FIG6 is only an example and does not constitute a limitation on the embodiments of this application. In specific implementation, the first temperature detection unit 6122 can be connected to any battery cell in the first series path via a signal line. Exemplarily, the first temperature detection unit 6122 can be any circuit or sensor capable of temperature detection, etc., and the embodiments of this application do not limit this.

[0069] The aforementioned first leakage detection unit 6123 can be used to detect leakage in the first series path. For example, as shown in FIG6, the first leakage detection unit 6123 is connected to the grounding wire (see grounding 1 in FIG6) in the first series path via a signal line, and the current on the grounding wire is fed back to the first leakage detection unit 6123 via the connected signal line. It is understood that the connection position of the grounding wire in FIG6 is only an example and does not constitute a limitation on the embodiments of this application. Exemplarily, the first leakage detection unit 6123 can be any circuit or sensor that can realize battery leakage detection, and the embodiments of this application do not limit it.

[0070] In another possible implementation, the first detection unit 612 may further include other detection units such as a voltage detection unit. For example, the voltage detection unit may be used to detect the voltage between any two points in the first series path. The above description of the first detection unit 612 is merely an example; in specific implementations, the first detection unit 612 may include more or fewer detection units, and this application embodiment does not impose any limitations on this.

[0071] In one possible implementation, as shown in Figure 7, the first protection unit 610 may further include an auxiliary power supply unit 614. This auxiliary power supply unit 614 can be used to connect an auxiliary power source or battery to the first protection unit 610 to power the first controller 611 and the first detection unit 612. Exemplarily, as shown in Figure 7, the auxiliary power supply unit 614 is connected to the first controller 611, and the power signal is first input to the first controller 611, and then input to the first detection unit 612 via the first controller 611. Alternatively, exemplarily, the auxiliary power supply unit 614 can be directly connected to the first detection unit 612 without going through the first controller 611 to power the first detection unit 612. This application embodiment does not limit this connection method. Exemplarily, the auxiliary power supply unit 614 may be, for example, a power supply circuit capable of voltage regulation, current regulation, or power conversion functions, and this application embodiment does not limit the specific structure of the auxiliary power supply unit 614.

[0072] For example, the auxiliary power supply connected to the first protection unit 610 may be the auxiliary power supply in the battery pack to which the battery module 600 belongs. For example, assuming the battery module 600 is the battery module 600 in the battery pack 1 shown in FIG. 5A, then the auxiliary power supply may be the auxiliary power supply in the battery pack 1. Alternatively, for example, the auxiliary power supply may be the auxiliary power supply in the energy storage system to which the battery module 600 belongs, and the auxiliary power supply may supply power to the BMS in the energy storage system. For example, assuming the battery module 600 is any one of the battery modules 600 in the energy storage system shown in FIG. 5A, then the auxiliary power supply may be the auxiliary power supply in the energy storage system. And the auxiliary power supply may be used to supply power to the first battery management unit 601 and / or the second battery management unit 602 in the energy storage system.

[0073] For example, the battery connected to the first protection unit 610 may be one or more cells in the battery module 600.

[0074] For example, as shown in FIG7, the auxiliary power supply can be connected to the auxiliary power supply unit 614 via diode D1. The battery can be connected to the auxiliary power supply unit 614 via diode D2. The negative terminals of diode D1 and diode D2 are connected together. The auxiliary power supply can be connected from the positive terminal of diode D1. The battery can be connected from the positive terminal of diode D2.

[0075] For example, in a specific implementation, if the battery pack or energy storage system to which the battery module 600 belongs is in an active state, then the first protection unit 610 can be powered by the auxiliary power supply. If the battery pack or energy storage system to which the battery module 600 belongs is in a dormant state, then the first protection unit 610 can be powered by the battery. For example, the voltage of the positive terminal of the auxiliary power input diode D1 can be set to be higher than the voltage of the positive terminal of the battery input diode D2. Under this design, if the first battery management unit 601 is in an active state and the voltage of the positive terminal of the auxiliary power input diode D1 is higher than the voltage of the positive terminal of the battery input diode D2, then the auxiliary power supply will preferentially power the first protection unit 610. If the first battery management unit 601 is in a dormant state and the voltage of the positive terminal of the auxiliary power input diode D1 is very low or even zero, the first protection unit 610 will be powered by the connected battery.

[0076] Alternatively, in another possible implementation, if the auxiliary power supply is the auxiliary power supply in the energy storage system to which the battery module 600 belongs, a switch can be set between the auxiliary power supply unit 614 and the interface where the auxiliary power supply is connected, as well as the interface where the battery is connected. Under this design, if the energy storage system is in operation (i.e., the BMS in the energy storage system is also in operation), the BMS can control the switch to close and connect the auxiliary power supply unit 614 and the interface where the auxiliary power supply is connected, so that the auxiliary power supply supplies power to the first protection unit 610. If the BMS is in sleep mode, before going into sleep mode, the BMS can control the switch to close and connect the auxiliary power supply unit 614 and the interface where the battery is connected, so that the connected battery supplies power to the first protection unit 610. For example, in one possible implementation, based on the above description, the first protection unit 610 can determine whether the BMS is in operation or sleep mode based on the object being powered. Specifically, if the first protection unit 610 detects a power signal from the interface where the auxiliary power supply is connected, it can know that the BMS is in operation. If the first protection unit 610 detects that the power signal comes from the interface where the battery is connected, it can know that the BMS is in a sleep state.

[0077] In the above scheme, if the battery pack or energy storage system to which battery module 600 belongs is operating, the auxiliary power supply powers the protection unit in the battery pack to reduce the impact of power supply from the battery module on the battery module itself. If the battery pack or energy storage system to which battery module 600 belongs is in a dormant state, the battery module can power the first protection unit 610 to ensure that abnormal detection and protection of the battery module can be achieved even when the battery pack or energy storage system to which battery module 600 belongs is in a dormant state. In addition, reusing the power supply of the battery module to power the first protection unit 610 also saves costs.

[0078] In another possible implementation, the first protection unit 610 may also be powered by other additional auxiliary power supplies, and this application embodiment does not limit this.

[0079] In one possible implementation, as shown in Figure 8, the battery module 600 may further include a second protection unit 640 and one or more battery cells 620 (Figure 8 shows three battery cells 620, 7 to 9, as examples). The second protection unit 640 may include a second controller 641, a second detection unit 642, and a second disconnecting device 643. It can be seen that the plurality of battery cells 620 and the second disconnecting device 643 are connected in series. For example, the second disconnecting device 643 is connected in series between battery cell 6 and battery cell 7. It is understood that the second disconnecting device 643 can be connected in series between any two adjacent battery cells from 4 to 9. For example, it can be connected in series between battery cell 7 and battery cell 8, etc., which are not listed here.

[0080] For example, since the battery cells 620 in the battery module 600 are connected in series, it can also be said that the second disconnecting device 643 is connected in series between any two of the battery cells 4 to 9. For example, the second disconnecting device 643 may be connected in series between battery cells 4 and 9. Or, the second disconnecting device 643 may be connected in series between battery cells 1 and 8. Or, the second disconnecting device 643 may be connected in series between battery cells 5 and 9. Or, the second disconnecting device 643 may be connected in series between battery cells 5 and 8, and so on.

[0081] For ease of description later, the circuit in which the battery cells 4 to 9 and the second disconnecting device 643 are connected in series will be referred to as the second series circuit.

[0082] The second controller 641 is connected to the second detection unit 642 and the second disconnecting device 643. The second detection unit 642 can detect abnormalities in the second series path and feed the detection results back to the second controller 641. If an abnormality occurs in the second series path, the second controller 641 can control the second disconnecting device 643 to disconnect, thereby cutting off the second series path and protecting the battery module 600. For example, the second detection unit 642 can detect second status information. This second status information indicates the status of the second series path. Specifically, the second status information may include, for example, the current flowing through the cell in the second series path, the temperature of the cell, or the leakage current of the second series path; this embodiment does not limit this. The second detection unit 642 or the second controller 641 can determine that an abnormality exists in the second series path through this second status information. This analysis process is similar to the analysis process for determining that an abnormality exists in the first series path.

[0083] In one possible implementation, the second detection unit 642 may include one or more of the following: a second current detection unit 6421, a second temperature detection unit 6422, and a second leakage current detection unit 6423. Figure 8 illustrates an example including these three units.

[0084] The aforementioned second current detection unit 6421 can be used to detect the current in the aforementioned second series path. For example, as shown in FIG8, the second current detection unit 6421 is connected to the second series path via a signal line, and the current in the second series path is fed back to the second current detection unit 6421 through the connected signal line. It is understood that the position of the second current detection unit 6421 connected to the second series path via the signal line in FIG8 is only an example and does not constitute a limitation on the embodiments of this application. In specific implementation, the second current detection unit 6421 can be connected to any position on the second series path via a signal line. Exemplarily, the second current detection unit 6421 can be any circuit or sensor capable of current detection, etc., and the embodiments of this application do not limit this.

[0085] The aforementioned second temperature detection unit 6422 can be used to detect the temperature of the aforementioned second series path. For example, as shown in FIG8, the second temperature detection unit 6422 is connected to the battery cell 6 in the second series path via a signal line, and the temperature of the battery cell 6 (which can be used to represent the temperature of the second series path) is fed back to the second temperature detection unit 6422 via the connected signal line. It is understood that the battery cell connected to the second temperature detection unit 6422 via the signal line in FIG8 is only an example and does not constitute a limitation on the embodiments of this application. In specific implementation, the second temperature detection unit 6422 can be connected to any battery cell in the second series path via a signal line. Exemplarily, the second temperature detection unit 6422 can be any circuit or sensor capable of temperature detection, etc., and the embodiments of this application do not limit this.

[0086] The second leakage detection unit 6423 described above can be used to detect leakage in the second series path. For example, as shown in FIG8, the second leakage detection unit 6423 is connected to the grounding wire (see grounding 2) in the second series path via a signal line, and the current on the grounding wire is fed back to the second leakage detection unit 6423 through the connected signal line. It is understood that the connection position of the grounding wire in FIG8 is only an example and does not constitute a limitation on the embodiments of this application. Exemplarily, the second leakage detection unit 6423 can be any circuit or sensor that can realize battery leakage detection, and the embodiments of this application do not limit it. Exemplarily, grounding 2 can be connected together with grounding 1, or it can be separate.

[0087] In another possible implementation, the second detection unit 642 may further include other detection units such as a voltage detection unit. For example, the voltage detection unit may be used to detect the voltage between any two points in the second series path. The above description of the second detection unit 642 is merely illustrative; in specific implementations, the second detection unit 642 may include more or fewer detection units, and this application embodiment does not impose any limitations on this.

[0088] In one possible implementation, as shown in Figure 8, the second protection unit 640 may further include an auxiliary power supply unit 644. This auxiliary power supply unit 644 can be used to connect an auxiliary power source or battery to the second protection unit 640 to power the second controller 641 and the second detection unit 642. For specific implementation details, please refer to the aforementioned description of the auxiliary power supply unit 614, which will not be repeated here. Furthermore, the auxiliary power source can be connected to the auxiliary power supply unit 644 via diode D3. The battery can be connected to the auxiliary power supply unit 644 via diode D4. For specific implementation details, please refer to the aforementioned description of diodes D1 and D2, which will not be repeated here.

[0089] In one possible implementation, see Figure 9 for example. The battery module 600 may also include more cells 620 connected in series, and more protection units (e.g., the third protection unit 650, the fourth protection unit 660, and the fifth protection unit 670 exemplarily shown in Figure 9). The descriptions of the third protection unit 650 and the fifth protection unit 670 can be found in the description of the first protection unit 610 described above, and the description of the fourth protection unit 660 can be found in the description of the second protection unit 640 described above; they will not be repeated here.

[0090] For example, as shown in Figures 8 and 9 above, multiple protection units can be set in the battery module, and different protection units protect different groups of battery cells. This is equivalent to grouping (or partitioning) the multiple battery cells 620 in the battery module for protection. The battery cells 620 included in different groups may overlap or not overlap. For example, grouping can be based on the voltage between the positive and negative terminals of the battery cell 620, the voltage across the series path (e.g., the first series path or the second series path mentioned above), and the insulation withstand voltage of the battery cell 620. Specifically, the voltage across the series path cannot be greater than the insulation withstand voltage of the battery cell 620. If the voltage across the series circuit is greater than the insulation withstand voltage of the battery cell 620, then, in the case where an external battery path (e.g., see the external battery path shown in Figure 4 or Figure 5) is generated between the battery cells at both ends of the series circuit, the maximum voltage applied to the battery cells at those ends is the voltage across the series circuit. Because the voltage across the series circuit is greater than the insulation withstand voltage of cell 620, the insulation of the cells at both ends may break down, leading to thermal runaway or even fire (see the relevant descriptions in Figure 4 or Figure 5 above for examples). For ease of understanding, the first series circuit described above will be used as an example below.

[0091] For example, in the first series circuit described above, assuming the voltage of cell 620 is a volts (V) and the insulation withstand voltage of cell 620 is b volts, the number of cells in each group can be calculated by dividing b by a, i.e., b / a. Assuming b / a = 6, six cells, or cells connected in series, can be grouped into one group, as shown in the first series circuit. Alternatively, the number of cells in a group can be greater than 1 and less than 6. The voltage across the first series circuit is the voltage across cells 1 through 6 connected in series. Therefore, the voltage across the first series circuit is 6a volts. This 6a is not greater than the insulation withstand voltage b of cell 620. Thus, an external circuit is created between cells 1 and 6, and the maximum voltage applied to cells 1 and 6 is 6a. This does not exceed the insulation withstand voltage b, therefore, cell insulation breakdown will not occur. If b / a = 5, then the voltage 6a volts across the first series circuit is greater than the insulation withstand voltage b (b = 5a). In this situation, if an external circuit is created between cell 1 and cell 6, the maximum voltage applied to cell 1 and cell 6 is 6a. If this voltage exceeds the insulation withstand voltage b, the cell insulation will break down.

[0092] In another possible implementation, see Figures 10A and 10B, which exemplarily illustrate two possible implementations of the cell grouping. For example, as shown in Figure 10A, protection units are disposed between cell groups. Exemplarily, Figure 10A illustrates four cell groups. The first protection unit 610 is disposed between the first and second cell groups, meaning the first disconnecting device 613 included in the first protection unit 610 is connected in series between the first and second cell groups. The second protection unit 640 is disposed between the second and third cell groups, meaning the second disconnecting device 643 included in the second protection unit 640 is connected in series between the second and third cell groups. The placement of the remaining protection units is similar and will not be described in detail.

[0093] For example, as shown in Figure 10B, the protection unit is disposed within a cell group. Exemplarily, Figure 10B illustrates three cell groups. The first protection unit 610 is disposed within the first cell group, meaning that the first disconnecting device 613 included in the first protection unit 610 is connected in series between the cells of the first cell group. The second protection unit 640 is disposed within the second cell group, meaning that the second disconnecting device 643 included in the second protection unit 640 is connected in series between the cells of the second cell group. The placement of the remaining protection units is similar and will not be described in detail.

[0094] For example, in Figures 10A and 10B above, the first detection unit 612 in the first protection unit 610 can be used to detect the status information of the first cell group; the first controller 611 is used to control the first disconnecting device 613 to disconnect when the status information indicates that the first cell group is abnormal. The second detection unit 642 in the second protection unit 640 can be used to detect the status information of the second cell group; the second controller 641 is used to control the second disconnecting device 643 to disconnect when the status information indicates that the second cell group is abnormal.

[0095] It is understood that the above grouping method is merely an example and does not constitute a limitation on the embodiments of this application. Furthermore, the number of cells included in each cell group can be determined based on the cell voltage and the cell insulation withstand voltage, and this application does not impose any limitations on this.

[0096] In summary, the above-described cell grouping protection scheme ensures that even if a casing path is formed between two cells within a group, the maximum voltage applied to the cell will not exceed the cell's insulation withstand voltage. This reduces the risk of cell insulation breakdown and effectively protects the battery. Furthermore, grouping allows for comprehensive and timely detection of anomalies and the implementation of protective measures.

[0097] In one possible implementation, the controller included in the protection unit of the battery module 600 can also be connected to the second battery management unit 602 in the energy storage system. For example, see Figure 11, which illustrates the connection between the first controller 611 of the first protection unit 610 in the battery module 600 and the second battery management unit 602. Furthermore, the first battery management unit 601 shown in Figure 11 is the first battery management unit in the battery pack to which the battery module 600 belongs. This first battery management unit 601 can collect status information of the battery pack to which the battery module 600 belongs. Exemplarily, this status information may include information such as current, temperature, or leakage current in the battery pack.

[0098] For example, in a specific implementation, the first battery management unit 601 can send the collected status information of the battery pack to the second battery management unit 602. The second battery management unit 602 can, if the status information indicates an abnormality in the battery pack, notify the first controller 611 to control the first disconnecting device 613 to disconnect. For example, the abnormality of the battery pack may include one or more of the following: the main circuit current in the battery pack detected by the first battery management unit 601 (e.g., the current at the positive or negative terminal of the battery pack) is greater than a preset current threshold; the temperature in the battery pack detected by the first battery management unit 601 is greater than a preset temperature threshold; the leakage current in the battery pack detected by the first battery management unit 601 is greater than a preset leakage current threshold, etc. This application embodiment does not limit the abnormality of the battery pack.

[0099] For example, when the first battery management unit 601 and the second battery management unit 602 are in normal working condition, the first protection unit 610 can operate or stop operating. If the first protection unit 610 is also operating, it can detect the status information in the first series path (or the first cell group), as detailed in Figure 12 below. If the detected status information indicates an abnormality, the first controller 611 will also control the first disconnecting device 613 to disconnect.

[0100] For example, if the first battery management unit 601 and the second battery management unit 602 are in a dormant state. For instance, when the energy storage system is in storage or transportation, in order to reduce the consumption of the remaining power of the batteries in the energy storage system by the first battery management unit 601 and the second battery management unit 602, they are generally in a dormant state. The first battery management unit 601 and the second battery management unit 602 can no longer detect the status information in the battery module 600. In this case, the first protection unit 610 can normally detect the status information in the first series path (or the first cell group). If the detected status information indicates an abnormality, the first controller 611 can control the first disconnecting device 613 to disconnect.

[0101] In the above scheme, when the first battery management unit 601 and the second battery management unit 602 (collectively referred to as BMS) are working, the BMS and / or the first protection unit 610 can detect the status information of the battery module 600. When the BMS is in sleep mode, the first protection unit 610 can also detect the status information of the battery module 600. Thus, comprehensive and effective protection of the battery module 600 is achieved.

[0102] The foregoing mainly provides an exemplary description of the structure of the energy storage system, battery, and battery module provided in the embodiments of this application, as well as the relationships between them. The specific implementation process of the battery protection method provided in the embodiments of this application will be described below, taking the first protection unit 610 as an example.

[0103] For example, in a specific implementation, if the first detection unit 612 includes a current detection unit (e.g., the first current detection unit 6121), then the first current detection unit 6121 can detect current abnormalities in the first series path, or in other words, detect current abnormalities in the first cell group. For ease of understanding, please refer to Figure 12. In Figure 12, an external cell path is created between the first cell (cell 1) and the second cell (cell 6) due to condensation, electrolyte leakage, coolant leakage, or insulation failure. The existence of this external cell path creates an additional current loop between cell 1, cell 2, cell 3, the first disconnecting device 613, cell 4, cell 5, and cell 6 (see the dashed line in Figure 12). This causes a change in the current in the first series path (or the first cell group).

[0104] For example, if the energy storage system to which the battery module 600 belongs is in a powered-on state, that is, the battery module 600 and the BMS of the energy storage system are in a working state, the battery module 600 is supplying power to the load, and there is already current in the first series path (or the first cell group). If the aforementioned external cell path appears between cell 1 and cell 2, forming the aforementioned additional current loop, the current flowing through the first series path (or the first cell group) will change. The aforementioned first current detection unit 6121 can detect this change in current. For example, the first current detection unit 6121 can compare the detected current of the first series path (or the first cell group) with the current at BAT-, the current at BAT+, or the current between BAT- and BAT+. Since it is a series connection, if no other current loop appears, the current of the first series path is the same as the current at BAT-, the current at BAT+, and the current between BAT- and BAT+. Based on this, if the comparison finds that the current is different, it indicates that the current of the first series path is abnormal. The first current detection unit 6121 can then feed back the comparison result to the first controller 611. The first controller 611 can then control the first disconnecting device 613 to disconnect.

[0105] In another implementation, the current at BAT-, the current at BAT+, or the current between BAT- and BAT+ can be detected by the BMS in the energy storage system to which the battery module 600 belongs. The first current detection unit 6121 can detect the current in the first series path (or the first cell group). Then, the BMS and the first current detection unit 6121 respectively send the detected current to the first controller 611. The first controller 611 compares the received current and controls the first disconnecting device 613 to disconnect in case of current abnormality. In one possible implementation, for example, the first battery management unit 601 in the battery pack to which the battery module 600 belongs can detect the current at BAT-, the current at BAT+, or the current between BAT- and BAT+. Then, the detected current is sent to the second battery management unit 602. The second battery management unit 602 then sends the detected current to the first controller 611. It is understood that the description of the detection of current at BAT-, current at BAT+, or current between BAT- and BAT+ is merely an example and does not constitute a limitation on the embodiments of this application. For example, if the energy storage system to which the battery module 600 belongs is not powered on, the BMS is in a dormant state. Under normal circumstances, there is no current in the first series path (or the first cell group). However, if the aforementioned external cell path appears between cell 1 and cell 2, forming the aforementioned additional current loop, then current flows through the first series path. The aforementioned first current detection unit 6121 can detect this change in current and feed the detection result back to the first controller 611. The first controller 611 can control the first disconnecting device 613 to disconnect. For example, the first current detection unit 6121 detects current and determines that the detected current is greater than zero. Then, the first current detection unit 6121 can feed back the detection result that the current is greater than zero to the first controller 611. The first controller 611 can control the first disconnecting device 613 to disconnect. Alternatively, for example, the first current detection unit 6121 detects a current and feeds the detected current back to the first controller 611. The first controller 611 determines that the detected current is greater than zero, and then controls the first disconnecting device 613 to disconnect.

[0106] In another possible implementation, regardless of whether the energy storage system to which the battery module 600 belongs is powered on, and regardless of whether the abnormality is determined by the first current detection unit 6121 or the first controller 611, a current threshold can be preset. If the current detected by the first current detection unit 6121 is greater than the current threshold, it indicates that the current is abnormal, and the first controller 611 can control the first disconnecting device 613 to disconnect.

[0107] For example, in a specific implementation, if the first detection unit includes a temperature detection unit (e.g., the first temperature detection unit 6122), then the temperature anomaly of the first series path (or the first cell group) can be detected by the temperature detection unit. For example, still referring to the example description in Figure 12 above, regardless of whether the BMS is in an operating state or a sleep state, if the aforementioned external cell path appears between cell 1 and cell 6, forming the aforementioned additional current loop, then the current flowing through the first series path (or the first cell group) increases compared to when the external cell path does not appear. The increased current will cause the temperature of the cells in the first series path to rise. The first temperature detection unit 6122 can detect this temperature change and feed the detection result back to the first controller 611. The first controller 611 can control the first disconnecting device 613 to disconnect.

[0108] For example, a temperature threshold can be preset. If the temperature detected by the first temperature detection unit 6122 is greater than the temperature threshold, the first controller 611 can control the first disconnecting device 613 to disconnect. For example, the first temperature detection unit 6122 detects a temperature and determines that the detected temperature is greater than the temperature threshold. Then, the first temperature detection unit 6122 can feed back the detection result that the temperature is greater than the temperature threshold to the first controller 611. The first controller 611 can then control the first disconnecting device 613 to disconnect. Alternatively, for example, the first temperature detection unit 6122 detects a temperature and feeds back the detected temperature to the first controller 611. The first controller 611 determines that the detected temperature is greater than the temperature threshold and then controls the first disconnecting device 613 to disconnect.

[0109] Alternatively, in another possible implementation, a temperature change threshold can be preset. If the difference between the changed temperature and the original temperature is greater than the preset temperature change threshold, the first controller 611 can control the first disconnecting device 613 to disconnect. The specific implementation is the same as the temperature threshold described in the previous section, and will not be repeated here.

[0110] For example, in a specific implementation, if the first detection unit includes a leakage current detection unit (e.g., the first leakage current detection unit 6123), then the leakage current of the first series path (or the first cell group) can be detected by the temperature detection unit. If leakage occurs in the first series path (or the first cell group), the current flowing through the grounding wire will increase. The first leakage current detection unit 6123 can detect this change in current and feed the detection result back to the first controller 611. The first controller 611 can control the first disconnecting device 613 to disconnect. For example, a leakage current threshold can be preset. If the leakage current detected by the first leakage current detection unit 6123 is greater than the leakage current threshold, then the first controller 611 can control the first disconnecting device 613 to disconnect. For example, the first leakage current detection unit 6123 detects a leakage current and determines that the detected leakage current is greater than the leakage current threshold. Then, the first leakage current detection unit 6123 can feed back the detection result that the leakage current is greater than the leakage current threshold to the first controller 611. The first controller 611 can control the first disconnecting device 613 to disconnect. Alternatively, for example, the first leakage current detection unit 6123 detects leakage current and feeds the leakage current back to the first controller 611. The first controller 611 determines that the detected leakage current is greater than the leakage current threshold, and then controls the first disconnecting device 613 to disconnect.

[0111] It is understandable that the above description mainly uses the first protection unit 610 in the battery module 600 as an example. In actual implementation, other protection units in the battery module 600 can also achieve the same function, which will not be elaborated here.

[0112] In one possible implementation, embodiments of this application can also provide protection against abnormal conditions occurring between series-connected battery packs. This will be illustrated below with reference to FIG13.

[0113] Figure 13 illustrates two battery packs connected in series in a battery module. Exemplarily, Figure 13 assumes that the protection unit and the battery cells are packaged together in the battery pack. The number of battery cells connected in series and the number of protection units in the battery pack are merely examples; in a specific implementation, more or fewer battery cells and protection units may be included. As shown in Figure 13, battery pack 1 includes protection unit 11, protection unit 12, and protection unit 13, as well as multiple battery cells connected in series. Similarly, battery pack 2 includes protection unit 21, protection unit 22, and protection unit 23, as well as multiple battery cells connected in series. Protection unit 11, protection unit 13, protection unit 21, and protection unit 23 can be exemplarily referred to as the first protection unit 610 described above. Protection unit 12 and protection unit 22 can be exemplarily referred to as the second protection unit 640 described above.

[0114] For example, in Figure 13 above, it is assumed that cell a in battery pack 1 and cell b in battery pack 2 have external circuits due to condensation, electrolyte leakage, coolant leakage, or insulation failure. The existence of these external circuits creates an additional current loop (see the dashed line in Figure 13). The current in the circuits of battery packs 1 and 2 changes as this current loop passes through them. Protection units 12, 13, 21, and 22 within this circuit can detect the current anomaly and disconnect their respective tripping devices based on this anomaly. The specific implementation of each protection unit can be found in the relevant description in Figure 12 above, and will not be repeated here.

[0115] In Figure 13 above, if the aforementioned protection unit is not present in the aforementioned path, the maximum voltage applied to cells a and b after the external path to the cells is generated may exceed the insulation withstand voltage of the two cells, causing the insulation of the two cells to break down, resulting in the risk of thermal runaway or even fire. Therefore, by setting the aforementioned protection unit in the battery pack, this embodiment of the application can reduce the risk of thermal runaway or even fire caused by the generation of external paths between cells in the battery pack, thus ensuring the safety of the battery module.

[0116] In summary, this application embodiment, by setting a protection unit in the battery module and connecting disconnecting devices in series between the cells, enables the rapid disconnection of the disconnecting devices in the event of abnormalities (such as overcurrent, overtemperature, or leakage) between the cells, thereby protecting the battery module. This solution provides effective battery module protection in scenarios where high voltage breaks down the cell insulation, or in situations where the BMS system malfunctions during storage or transportation, preventing protection of the battery module.

[0117] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0118] It should also be understood that the term “comprising” (also referred to as “includes”, “including”, “comprises” and / or “comprising”) as used in this specification specifies the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0119] It should also be understood that the phrases "an embodiment," "an embodiment," and "a possible implementation" used throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment or implementation is included in at least one embodiment of this application. Therefore, the phrases "in an embodiment," "an embodiment," or "a possible implementation" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery module, characterized in that, The battery module includes a first protection unit, a first battery cell, and a second battery cell; the first protection unit includes a first disconnect device, a first detection unit, and a first controller; The first battery cell and the second battery cell are connected in series; The first disconnecting device is connected in series between the first battery cell and the second battery cell; The first detection unit is used to detect first state information, which is used to indicate the state of the battery module; The first controller is used to control the first disconnect device to disconnect when the first status information indicates that the battery module is abnormal.

2. The battery module according to claim 1, characterized in that, The first cell and the second cell belong to the first cell group of the battery module; the battery module also includes a second cell group, which includes a third cell and a fourth cell; the total voltage of the first cell group is less than or equal to the insulation withstand voltage of the first cell or the second cell, and the total voltage of the second cell group is less than or equal to the insulation withstand voltage of the third cell or the fourth cell; The first status information is used to indicate the status of the first cell group; The first controller is used to control the first disconnect device to disconnect when the first status information indicates that the first cell group is abnormal. The battery module further includes a second protection unit; the second protection unit includes a second disconnect device, a second detection unit, and a second controller. The second disconnecting device is connected in series between the third cell and the fourth cell; The second detection unit is used to detect second status information; the second status information is used to indicate the status of the second cell group. The second controller is used to control the second disconnect device to disconnect when the second status information indicates that the second cell group is abnormal.

3. The battery module according to claim 1, characterized in that, The first cell belongs to a first cell group, and the second cell belongs to a second cell group; the battery module also includes a third cell group, and the third cell group includes a fifth cell; the total voltage of the first cell group is less than or equal to the insulation withstand voltage of the first cell, the total voltage of the second cell group is less than or equal to the insulation withstand voltage of the second cell, and the total voltage of the third cell group is less than or equal to the insulation withstand voltage of the fifth cell; The first status information is used to indicate the status of the first cell group; The first controller is used to control the first disconnect device to disconnect when the first status information indicates that the first cell group is abnormal. The battery module also includes a third protection unit, which includes a third disconnect device, a third detection unit, and a third controller. The third disconnecting device is connected in series between the second battery cell and the fifth battery cell; The third detection unit is used to detect third status information; the third status information is used to indicate the status of the second cell group. The third controller is used to control the third disconnect device to disconnect when the third status information indicates that the second cell group is abnormal.

4. The battery module according to any one of claims 1-3, characterized in that, The first disconnecting device is an explosive fuse, a contactor, a relay, or a semiconductor switch.

5. The battery module according to any one of claims 1-4, characterized in that, The first detection unit includes a current detection unit, which is used to detect the current between the first battery cell and the second battery cell; The first controller is configured to control the first disconnecting device to disconnect when the current is different from the current at the positive or negative terminal of the battery module; or... The first controller is used to control the first disconnecting device to disconnect when the current is greater than a first threshold.

6. The battery module according to any one of claims 1-5, characterized in that, The first detection unit includes a temperature detection unit, which is used to detect the temperature of the first battery cell or the second battery cell; The first controller is used to control the first disconnecting device to disconnect when the temperature of the first cell or the second cell is greater than a second threshold.

7. The battery module according to any one of claims 1-6, characterized in that, The first detection unit includes a leakage current detection circuit, which is connected to the grounding wire of the battery module and is used to detect the current flowing through the grounding wire. The first controller is used to control the first disconnecting device to disconnect when the current flowing through the grounding wire is greater than a third threshold.

8. The battery module according to any one of claims 1-7, characterized in that, The first detection unit and the first controller are powered by one or more cells in the battery module.

9. A battery pack, characterized in that, The battery pack includes the battery module as described in any one of claims 1-7 and the first battery management unit; The first battery management unit is used to collect the status information of the battery pack.

10. The battery pack according to claim 9, characterized in that, The battery pack also includes a first auxiliary power supply, and the first detection unit and the first controller in the battery module are powered by the first auxiliary power supply.

11. An energy storage system, characterized in that, The energy storage system includes a battery pack as described in claim 9 and a second battery management unit; the second battery management unit is connected to the first battery management unit and to the first controller included in the battery module; The second battery management unit is used to receive the status information of the battery pack collected by the first battery management unit; The second battery management unit is also configured to notify the first controller to disconnect the first disconnect device when the status information indicates that the battery pack is abnormal.

12. The energy storage system according to claim 11, characterized in that, The energy storage system also includes a second auxiliary power supply, and the first detection unit and the first controller are powered by the second auxiliary power supply.

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