Battery pack and energy storage system

Abstract

The embodiment of the invention provides a battery pack and an energy storage system. A protection assembly aiming at a battery cell is additionally introduced outside the battery cell in the battery pack, and the protection assembly is a micro conductive circuit. The micro-conduction circuit corresponding to the battery cell is connected between the positive pole of the battery cell and the cover plate, and a fixed-value resistor is arranged in the micro-conduction circuit and is used for increasing the potential of the cover plate to be equal to the potential of the positive pole. And the potential of the cover plate is relatively higher than that of the negative pole and is higher than a safety potential (such as 0.26 V), so that the cover plate of the battery cell is effectively prevented from being corroded. The energy storage system where the battery pack is located also has higher reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and in particular to a battery pack and an energy storage system. BACKGROUND

[0002] A battery cell is an energy storage unit that constitutes an energy storage system. From a battery cell to a complete energy storage system, it is a hierarchical integration process, which can include but is not limited to: multiple battery cells are connected together to form a battery module to improve voltage and capacity. The battery module and components such as a battery controller and a power converter are combined to form a battery pack with charging and discharging functions. Multiple battery packs and components such as a battery management system are combined to form an energy storage system that can realize energy storage, scheduling and management.

[0003] The battery cells in the energy storage system are arranged densely. If a battery cell has thermal runaway due to corrosion perforation or short circuit, the huge heat generated by the battery cell will be quickly transferred to the adjacent battery cells, causing the adjacent battery cells to also have thermal runaway. This can cause the battery pack in the energy storage system to catch fire and explode, resulting in disastrous consequences.

[0004] Ensuring that the battery cells can operate safely and durably and stably is an important prerequisite for maintaining the reliability of the energy storage system. In order to ensure that the battery cells can operate safely and durably and stably, protection needs to be implemented on the battery cells. SUMMARY

[0005] Embodiments of the present application provide a battery pack and an energy storage system. A micro-conductive path is connected between the positive pole of a battery cell and the cover plate of the battery cell in the battery pack. The micro-conductive path can actively raise the potential of the cover plate of the battery cell, effectively preventing the cover plate of the battery cell from being electrochemically corroded. At the same time, when the micro-conductive path has a short circuit risk, the micro-conductive path is disconnected to avoid the cover plate of the battery cell and the positive pole from generating local overcurrent and heating due to the short-circuited micro-conductive path. In addition, in the case where the micro-conductive path is disconnected, it is also possible to detect whether the insulation between the battery cells is failed and trigger protection when the insulation is failed. From the aspects of active corrosion prevention, short circuit avoidance and insulation detection, the battery cells are protected in multiple ways, thereby improving the safety of the battery pack and the energy storage system.

[0006] In a first aspect, embodiments of the present application provide a battery pack, characterized in that the battery pack includes a plurality of battery cells and a plurality of micro-conductive paths, the plurality of battery cells and the plurality of micro-conductive paths are one-to-one corresponding and connected; each battery cell includes a positive pole, a negative pole, a shell and a cover plate, the cover plate is arranged on the shell, the positive pole and the negative pole pass through the cover plate, and an insulation structure is arranged between the negative pole and the cover plate; the micro-conductive path corresponding to the battery cell is connected between the positive pole of the battery cell and the cover plate of the battery cell, and the micro-conductive path corresponding to the battery cell includes a resistor.

[0007] In the above embodiment, the positive terminal is connected to the positive tab of the battery cell, and the positive terminal can serve as the positive terminal of the battery cell to the outside. The negative terminal is connected to the negative tab of the battery cell, and the negative terminal can serve as the negative terminal of the battery cell to the outside. The cover plate can be an aluminum cover plate. The resistor is a fixed resistor. The resistor is located on a circuit board outside the battery cell.

[0008] The resistor in the micro-conductive circuit can be used to increase the potential of the cover plate, making the potential of the cover plate higher than that of the negative terminal, effectively preventing electrochemical corrosion of the cover plate of the cell and suppressing insulation failure between the negative terminal and the cover plate.

[0009] The migration of lithium ions in the electrolyte within a battery cell between the positive and negative electrodes is crucial for normal charging and discharging. When the potential of the cover plate is low (e.g., below 0.26V), the cover plate becomes attractive to lithium ions. During migration, the lithium ions are drawn to the inner surface of the cover plate (the side in contact with the electrolyte), where a reaction occurs, causing corrosion and producing corrosion products. This can lead to cover plate damage and electrolyte leakage. The negative impacts of leaked electrolyte include, but are not limited to, affecting the stability of the insulation structure between battery cells. Electrolyte is volatile; electrolyte vapor can cause thermal runaway or even deflagration when exposed to high temperatures.

[0010] The purpose of the micro-conducting circuit is to raise the potential of the cover plate to a safe range (e.g., greater than 0.26) to prevent corrosion on the inner surface of the cover plate and the generation of corrosion products.

[0011] In conjunction with the first aspect, in some embodiments, an insulating structure is provided between the positive terminal and the cover plate.

[0012] In the above embodiments, electrical isolation between the positive terminal and the cover plate is ensured, reducing the risk of short circuit between the positive terminal and the cover plate of the battery cell. The insulation structure between the positive terminal and the cover plate can be combined with the insulation structure between the negative terminal and the cover plate to form a complete double insulation barrier, further improving the insulation reliability of the battery cell and providing a stable foundation for the normal operation of the micro-conductive circuit.

[0013] In conjunction with the first aspect, in some embodiments, the micro-conducting circuit corresponding to the battery cell also includes a switch, which is connected in series with a resistor; when the switch is closed, the positive terminal of the battery cell is connected to the cover plate of the battery cell through the micro-conducting circuit, thereby increasing the potential of the cover plate. When the switch is open, the positive terminal of the battery cell and the cover plate are insulated.

[0014] In the above embodiments, the switch allows the positive terminal and the cover plate to switch to a double-insulated state. This supports disconnecting the switch in the micro-conducting circuit when it is short-circuited, preventing localized overcurrent and overheating of the cell's cover plate and positive terminal due to the connection to the short-circuited micro-conducting circuit.

[0015] In conjunction with the first aspect, in some embodiments, the battery pack further includes a battery controller, which is used to control the switches in the micro-conducting circuits corresponding to other cells to disconnect when the voltage between the cover plate and the positive terminal of one cell is greater than or equal to a first voltage threshold; the other cells include at least one cell that is adjacent to the first cell among a plurality of cells.

[0016] The battery cell involved in the above embodiments can be battery cell a in the embodiments. If the voltage between the positive terminal and the cover plate of the battery cell is greater than or equal to a first voltage threshold, it indicates that the micro-conductive circuit corresponding to that battery cell is open-circuited. This may be because an abnormal operating condition causes the resistor in the micro-conductive circuit corresponding to that battery cell to be broken down by high voltage and disconnected, or the wire in the micro-conductive circuit is broken, resulting in an open circuit. The abnormal operating condition, while affecting this battery cell, may also affect adjacent battery cells (other battery cells mentioned above, such as battery cell b in the embodiments). For example, it may cause the resistor in the micro-conductive circuit corresponding to other battery cells to be broken down by high voltage but not disconnected, forming a short circuit. Therefore, it is necessary to disconnect the switch in the micro-conductive circuit corresponding to other battery cells to defensively protect them.

[0017] In conjunction with the first aspect, in some embodiments, the other cells include all cells other than one of the plurality of cells.

[0018] In the above embodiments, when there is an open circuit in the micro-conductive circuit corresponding to a battery cell, the scope of defensive protection against other battery cells can be maximized.

[0019] In conjunction with the first aspect, in some embodiments, the plurality of battery cells includes a first battery cell and a second battery cell, and the switches in the micro-conducting circuits corresponding to the first battery cell, the second battery cell, and the battery cells between them are all open or all closed; the battery controller is used to send a first message when the voltage between the cover plate of the first battery cell and the cover plate of the second battery cell is not equal to a first voltage, the first message being used to indicate an insulation failure between the first battery cell and the second battery cell; when the plurality of battery cells are connected in series, the first voltage satisfies: V1 = V11 + V12, where V1 is the first voltage, V11 is the sum of the battery cell voltages of the battery cells connected in series between the first battery cell and the second battery cell, and V12 is the battery cell voltage of the second battery cell; the potential of the positive terminal of the second battery cell is higher than the potential of the positive terminal of the first battery cell.

[0020] In the above embodiments, comparing the voltage between the cover plates of the first and second battery cells with a first voltage is for insulation detection to determine whether there is an insulation failure between the first and second battery cells. To ensure the accuracy of the insulation detection, the switching states of the switches in the micro-conductive circuits corresponding to the battery cells participating in the insulation detection must be consistent (both open or both conducting). Insulation failure can be a consequence of partial micro-conductive circuit abnormalities (open circuit or short circuit) or a cause of partial micro-conductive circuit abnormalities. Therefore, the timing of executing the insulation failure detection can include: after detecting an open circuit in the micro-conductive circuit corresponding to a battery cell and closing the switches in the micro-conductive circuits corresponding to the adjacent battery cells. In this case, an example of the first and second battery cells can be battery cells c and d involved in the embodiments. The timing of executing the insulation failure detection can also include: even if no open circuit is detected in the micro-conductive circuit corresponding to a battery cell, insulation detection can still be performed. In this case, an example of the first and second battery cells can be battery cells e and f involved in the embodiments. In the case of insulation failure, a first message is sent. The battery controller can send a first message to the system controller to notify it of an insulation failure within the battery pack. Upon receiving the first message, the system controller allocates the power of the faulty battery pack (with insulation failure) to other battery packs with intact insulation, and instructs the battery controller to stop charging and discharging the battery packs. This ensures that the power output and power input of the energy storage system are not affected by the faulty battery pack.

[0021] In conjunction with the first aspect, in some embodiments, when the switches in the micro-conductive circuits corresponding to the first cell, the second cell, and the cell between them are all closed, and the voltage between the cover plate of the first cell and the cover plate of the second cell is not equal to the first voltage, the battery controller is further configured to control the switches in the micro-conductive circuits corresponding to the first cell, the second cell, and the cell between them to open.

[0022] In the above embodiments, insulation failure can lead to abnormalities in the micro-conducting circuits corresponding to the first battery cell, the second battery cell, and the battery cell between them. For example, it can cause the resistor in the micro-conducting circuit to be broken down by high voltage but not disconnected, forming a short circuit. Therefore, it is necessary to disconnect the switches in the micro-conducting circuits corresponding to the first battery cell, the second battery cell, and the battery cell between them to defensively protect the first battery cell, the second battery cell, and the battery cell between them.

[0023] In conjunction with the first aspect, in some embodiments, the first battery cell and the second battery cell are arranged adjacent to each other.

[0024] The above embodiment performs insulation testing on two adjacent battery cells. This allows for a more accurate location of the insulation failure area between two adjacent battery cells.

[0025] In conjunction with the first aspect, in some embodiments, multiple battery cells are arranged in multiple rows and columns, adjacent to each other, including the first battery cell and the second battery cell being in the same row, or the first battery cell and the second battery cell being in the same column.

[0026] In the above embodiments, adjacent cells can be either adjacent cells in the same row or adjacent cells in the same column. This enhances the breadth of insulation testing. It allows for more comprehensive insulation testing between adjacent cells, providing more complete protection for the cells.

[0027] In conjunction with the first aspect, in some embodiments, the battery pack further includes a voltage acquisition circuit, which includes a first terminal and a second terminal; the first terminal is used to connect to the cover plate of a battery cell; the second terminal is used to connect to the positive terminal of a battery cell to obtain the voltage between the positive terminal of a battery cell and the cover plate, or the second terminal is used to connect to the cover plate of another battery cell to obtain the voltage between the cover plates of one battery cell and the cover plates of another battery cell.

[0028] In the above embodiments, it is not necessary to configure a separate voltage sampling circuit for each battery cell. Instead, multiple battery cells can share a single voltage acquisition circuit. This voltage acquisition circuit adopts a time-sharing voltage acquisition mechanism, which can collect the voltage between the positive terminal and the cover plate of different battery cells at different times, and determine whether the micro-conductive circuit corresponding to each battery cell is open-circuited. In this way, the space occupied by the voltage acquisition circuit on the circuit board and the hardware cost can be saved. The time-sharing voltage acquisition mechanism, combined with preventive protection for the battery cells, can save space and hardware costs while taking into account the protection of the battery cells. Among them, the preventive protection for the battery cells includes: detecting the presence of multiple open-circuit micro-conductive circuits corresponding to the battery cell, and, in the event of insulation failure, preventively shutting down the switches in the micro-conductive circuits corresponding to adjacent battery cells.

[0029] Secondly, embodiments of this application provide an energy storage system, which includes a battery pack as described in any of the first aspects above; the energy storage system also includes a DC bus, and all battery packs in the energy storage system are connected to the DC bus.

[0030] In conjunction with the second aspect, in some embodiments, the energy storage system also includes a system controller;

[0031] The system controller is configured to acquire a second message indicating an insulation failure between cells in the first battery pack; the system controller is also configured to control the first battery pack to stop supplying power to the DC bus, and to control the first battery pack to stop receiving power from the DC bus.

[0032] In the above embodiments, the second message can be an example of the aforementioned first message. After receiving the second message, the system controller stops the charging and discharging of the first battery pack (which has insulation failure) to prevent further damage to the first battery pack due to insulation failure during continued charging and discharging. Attached Figure Description

[0033] Figure 1 An exemplary application of battery cells in an energy storage system is shown;

[0034] Figure 2 This illustrates a battery cell and a protective measure for the battery cell;

[0035] Figure 3 An exemplary battery pack related to an embodiment of this application is shown;

[0036] Figure 4 Another exemplary battery cell is shown;

[0037] Figure 5 A schematic diagram is shown showing how the battery controller obtains voltage through a voltage acquisition circuit;

[0038] Figure 6 A schematic diagram is shown showing the voltage of the cover plate of two battery cells acquired through a voltage acquisition circuit;

[0039] Figure 7 An exemplary energy storage system provided in an embodiment of this application is illustrated. Detailed Implementation

[0040] Firstly based on Figure 1 This describes exemplary applications of battery cells in energy storage systems. Combined with... Figure 2 This describes a protective measure for battery cells.

[0041] like Figure 1 As shown, multiple battery cells (e.g., cells 1-6) are connected in series to form a battery module. The battery module, along with components such as a battery controller and a power converter, is combined to form a battery pack with charging and discharging capabilities.

[0042] In addition to the battery pack, an energy storage system also includes a battery management system (BMS) that manages the battery pack. The controller within the BMS that manages the battery pack can be called the system controller. Figure 1 (Not shown in the image).

[0043] The system controller can be used to manage the charging and discharging of multiple battery packs in an energy storage system. This includes: the system controller issuing charging and discharging control commands to the battery controllers in each battery pack; the battery controllers generating control signals for the power converter based on these commands; and the power converter using these control signals to control the charging and discharging of the battery modules.

[0044] When the battery module discharges to provide power to external devices, the power converter converts the DC power from the battery module and transmits it to the DC bus. At this time, the DC power on the DC bus is converted to AC power by the inverter and then supplied to external devices (such as the power grid, loads, etc.). The inverter can be installed outside the energy storage system or integrated with it as a single unit.

[0045] When the battery module is charging and absorbing power from external devices, the power converter is used to convert the DC power on the DC bus and transmit it to the battery module in the battery pack. Here, the DC power on the DC bus is obtained by the inverter converting the AC power provided by the external devices.

[0046] based on Figure 1 It is evident that battery cells are the basic energy storage units that constitute an energy storage system. Ensuring the safe and stable operation of battery cells is a crucial prerequisite for maintaining the reliability of the energy storage system.

[0047] Figure 1 In the energy storage system shown, no protective components for the battery cells are installed outside the cells. Protective components for the cells are located on the cell body and are part of the cell. For a type of battery cell with protective components installed on the cell body and its protective measures, please refer to the following... Figure 2 The description.

[0048] like Figure 2 As shown, the battery cell includes a positive terminal, a negative terminal, and a casing.

[0049] The outer casing of a battery cell includes a cover plate and a housing. The housing houses the cell's electrode assembly (including the positive and negative electrodes) and electrolyte. The cover plate seals the housing and secures the positive and negative terminals. The positive terminal is connected to the positive tab of the cell and serves as the positive terminal to the outside. The negative terminal is connected to the negative tab of the cell and serves as the negative terminal to the outside.

[0050] Continue to refer to Figure 2 In some embodiments, the negative terminal is insulated from and fixed to the cover plate by an insulating structure. The positive terminal is fixed to the cover plate by a conductive structure. Furthermore, a weak conductive path is established between the positive terminal and the cover plate through this conductive structure to raise the potential of the cover plate to a safe range (e.g., greater than 0.26V) and prevent corrosion of the cover plate.

[0051] It should be noted here that the lithium ions (Li) in the electrolyte of the battery cell +The migration of lithium ions between the positive and negative electrodes is crucial for the normal charging and discharging of the battery cell. When the potential of the cover plate is low (e.g., below the corrosion threshold, 0.26V), the cover plate becomes attractive to lithium ions. During migration, the lithium ions are attracted to the inner surface of the cover plate (the side in contact with the electrolyte), where they react and corrode, producing corrosion products. This can lead to damage and perforation of the cover plate, causing electrolyte leakage. The negative impacts of leaked electrolyte include, but are not limited to: affecting the stability of the insulation structure between the cells; the electrolyte is volatile, and electrolyte vapor can cause thermal runaway or even deflagration when exposed to high temperatures.

[0052] It's also important to note that, generally speaking, the largest potential difference inside a battery exists between the highest potential positive electrode and the lowest potential negative electrode. Therefore, the starting point and high-incidence area of ​​cover corrosion is near the negative electrode (the cover around the negative electrode). These corrosion products around the negative electrode accumulate and slowly destroy the insulation structure between the negative electrode post and the cover, leading to insulation failure. After insulation failure, the negative electrode post will come into contact with the cover (this is also known as a negative short circuit; a negative short circuit is not a low-resistance high-current short circuit, but a type of contact corrosion). Contact between the negative electrode post and the cover directly pulls the cover's potential down to the negative electrode potential (0V), further exacerbating corrosion.

[0053] In this embodiment, the potential of the cover plate of the battery cell is typically based on the Li-C of the battery cell. + The / Li electrode (usually the negative electrode) is used as a zero potential reference point.

[0054] Figure 2 The battery cell shown has a conductive structure between the positive terminal and the cover plate to increase the potential of the cover plate and prevent corrosion. However, Figure 2 The forming process of the conductive structure shown includes, but is not limited to: filling the gap between the positive electrode post and the cover plate of the battery cell with a high-viscosity slurry by extrusion injection molding under high temperature and high pressure conditions, followed by cooling and shaping. The high-viscosity slurry can be prepared by mixing a certain proportion of conductive materials (such as carbon black, carbon nanotubes, etc.) with polymers such as polyphenylene sulfide (PPS) as the matrix.

[0055] However, such molding processes can also lead to uneven resistance distribution in different regions of the conductive structure. Some regions of the conductive structure have resistances as low as ohms, while others have resistances as high as tens of thousands of ohms. The reasons for this uneven resistance distribution include, but are not limited to: firstly, uneven mixing of the conductive material with the polymer in a high-viscosity slurry, resulting in uneven distribution of the conductive material in the slurry, with some areas densely packed (forming low-resistance regions) or sparsely packed (forming high-resistance regions). Secondly, even slight fluctuations in parameters such as temperature and pressure during injection molding of the high-viscosity slurry can directly affect its dispersion. Uneven dispersion of the high-viscosity slurry leads to uneven resistance values ​​in the conductive structure.

[0056] It should be noted that the molding process of the insulating structure (e.g., the insulating structure filling the gap between the negative terminal and the cover plate) involved in the embodiments of this application includes, but is not limited to: filling the gap between the positive terminal and the cover plate of the battery cell with insulating materials such as plastic and / or ceramics by extrusion injection molding under high temperature conditions, followed by cooling and shaping. Wherein, when the insulating material is plastic, the insulating structure can also be referred to as a plastic part.

[0057] The low-resistance region in the battery cell's conductive structure has insufficient withstand voltage. This low-resistance region is easily broken down by high voltage, forming a partial open circuit or short circuit. A partial open circuit occurs when the low-resistance region breaks down, generating extremely high heat that burns and melts the region, creating an open circuit. After a partial open circuit, the conductive structure cannot further increase the voltage of the cover plate, which exposes the cover plate to corrosion. A partial short circuit occurs when the low-resistance region breaks down, generating high heat, but not enough to completely melt the region, leading to a low-resistance path and a short circuit. A short circuit can trigger a large local current, easily causing thermal runaway.

[0058] The high voltage that breaks down the low-resistance region refers to the high voltage formed when the voltage between the positive terminal of the battery cell and the cover plate increases sharply. The causes of high voltage include, but are not limited to: the battery cell encountering abnormal operating conditions (such as physical damage to components other than the battery cell, or abnormal control logic), causing the potential of the positive terminal of the battery cell to rise sharply, but the conductive structure cannot raise the potential of the cover plate to the same level (equal to the potential of the positive terminal) in time, thus forming high voltage.

[0059] To avoid the aforementioned problem where low-resistance regions in the conductive structure (filling the gap between the positive terminal of the battery cell and the cover plate) are easily broken down by high voltage, embodiments of this application provide a battery pack. An additional protective component for the battery cell is introduced outside the battery cell in this battery pack; this protective component is a micro-conductive circuit. The micro-conductive circuit corresponding to the battery cell is connected between the positive terminal of the battery cell and the cover plate. A fixed resistor is provided in this micro-conductive circuit to raise the potential of the cover plate to be equal to the potential of the positive terminal. This ensures that the potential of the cover plate is higher than the potential of the negative terminal, and higher than the safe potential (e.g., 0.26V), effectively preventing corrosion of the battery cell's cover plate.

[0060] It should be noted that when A (e.g., the potential of the cover plate) is equal to B (e.g., the potential of the positive terminal) mentioned in the embodiments of this application, it does not mean that A is strictly equal to B. If the difference between A and B is within a reasonable error range, A can also be considered equal to B.

[0061] A fixed resistor (or simply resistor) is a resistor whose resistance distribution is consistent across different regions at any given time. As time changes, the resistance of a fixed resistor can remain unchanged (e.g., any value between 3kΩ and 5kΩ) regardless of external factors (such as temperature), or, if affected by external factors (such as temperature), its resistance can vary within a narrower range (e.g., 3kΩ-5kΩ). This "narrower" range is narrower than the resistance distribution range of the conductive structures mentioned earlier.

[0062] In micro-conductive circuits, the resistance values ​​are uniformly distributed, resulting in high voltage withstand capability and eliminating low-resistance regions with insufficient withstand voltage. Compared to the aforementioned conductive structures, micro-conductive circuits avoid the risk of breakdown due to insufficient localized withstand voltage. This further reduces the risk of open or short circuits in the positive terminal and cover plate of the battery cell.

[0063] The resistors in the embodiments of this application with consistent resistance distribution in different regions do not mean that the resistance values ​​in different regions must be completely equal. Within a reasonable error range, they can also be referred to as consistent.

[0064] It's important to note that the "micro" in "micro-conductor circuit" refers to the extremely weak current flowing through the circuit when it's normally conducting through the positive terminal and the cover plate. By using a high-precision fixed resistor, the current in the micro-conductor circuit is strictly limited to the microampere level, increasing the cover plate potential to prevent corrosion without causing thermal risks.

[0065] Figure 3 An exemplary battery pack related to an embodiment of this application is shown. Figure 4 An exemplary cell in a battery pack is shown.

[0066] The following is combined with Figure 3 and Figure 4The present application provides an exemplary description of the battery pack, the battery cells therein, and the protection measures for the battery cells involved in the embodiments.

[0067] like Figure 3 As shown in the embodiments of this application, the battery pack includes multiple battery cells (e.g., cell 1 to cell n) and multiple micro-conductive circuits, with each battery cell corresponding to and connected to one of the multiple micro-conductive circuits. It can also be understood that different battery cells correspond to different micro-conductive circuits.

[0068] like Figure 4 As shown, each cell in the battery pack includes a positive terminal, a negative terminal, a casing, and a cover. The positive and negative terminals pass through the cover. An insulating structure is provided between the negative terminal and the cover. Alternatively, the gap between the negative terminal and the cover can be understood as being filled with an insulating structure, and the negative terminal is insulated and fixed to the cover through this insulating structure.

[0069] The micro-conducting circuit corresponding to the battery cell is connected between the positive terminal of the battery cell and the cover plate of the battery cell. The micro-conducting circuit corresponding to the battery cell includes a resistor (denoted as R).

[0070] It should be noted that the resistor in the micro-conductive circuit can be used to increase the potential of the cover plate when there is an insulating structure between the negative terminal and the cover plate.

[0071] It's important to note that if there's no insulation between the negative terminal and the cover plate, and they are in conductive contact, then the contact area between them is larger than the contact area between the micro-circuit and the cover plate. Therefore, the negative terminal's impact on the cover plate's potential is greater than the micro-circuit's impact on the cover plate's potential. For the micro-circuit to raise the cover plate's potential, the presence of an insulation structure between the negative terminal and the cover plate is essential. This prevents the negative terminal from contacting the cover plate, which could lower the cover plate's potential and cause corrosion.

[0072] In some possible embodiments, the same as described above Figure 2 The positive terminal of the battery cell can be fixed to the cover plate through a conductive structure. In this way, the conductive structure and the micro-conductive circuit are connected in parallel between the positive terminal of the battery cell and the cover plate, jointly increasing the voltage of the cover plate. Thus, when the conductive structure is broken down by high voltage, causing an open circuit, the micro-conductive circuit can still increase the potential of the cover plate. However, the risk of a short circuit caused by the high-voltage breakdown of the conductive structure cannot be avoided.

[0073] like Figure 4 As shown, to avoid the risk of short circuits caused by high voltage breakdown of the conductive structure, in some other possible embodiments, the positive terminal of the battery cell and the cover plate are not fixed together by a conductive structure. Instead, the positive terminal of the battery cell is fixed to the cover plate by an insulating structure. This can also be understood as an insulating structure being provided between the positive terminal of the battery cell and the cover plate of the battery cell.

[0074] This ensures electrical isolation between the positive terminal and the cover plate. Compared to the aforementioned scheme that fills the gap between the positive terminal and the cover plate with a conductive structure, the scheme that fills the gap between the positive terminal and the cover plate with an insulating structure reduces the risk of short circuits between the positive terminal and the cover plate. The insulating structure between the positive terminal and the cover plate can be combined with the insulating structure between the negative terminal and the cover plate to form a complete double insulation barrier, further improving the insulation reliability of the cell and providing a more stable foundation for the normal operation of the micro-conductive circuit.

[0075] It should be noted here that... Figure 4 and Figure 2 Components with the same name have the same function. Figure 4 The positive electrode, negative electrode, and casing shown in the diagram can be referenced in the aforementioned section. Figure 2 The relevant content will not be repeated here.

[0076] Continue to refer to Figure 3 The micro-conductive circuit corresponding to the battery cell also includes a switch (such as switch S in the figure), which is connected in series with a resistor in the micro-conductive circuit. The switch in the micro-conductive circuit is used to switch the positive terminal and the cover plate of the battery cell between insulation and conduction.

[0077] When the switch in the micro-conductive circuit corresponding to the battery cell is closed, the positive terminal of the battery cell is connected to the cover plate of the battery cell through the micro-conductive circuit, thereby increasing the potential of the cover plate.

[0078] The switch in the micro-conductive circuit corresponding to the battery cell is disconnected to insulate the positive terminal and the cover plate of the battery cell.

[0079] The switch in the micro-conducting circuit allows the positive terminal and the cover plate to switch to a double-insulation state. When the micro-conducting circuit is short-circuited, disconnecting the switch prevents localized overcurrent and overheating of the cell's cover plate and positive terminal due to the connection to the short-circuited micro-conducting circuit. Double insulation means that the negative terminal and the cover plate are insulated from each other. In the double-insulation state, the potential of the cell's cover plate is floating, neither pulled up by the positive terminal nor pulled down by the negative terminal. Typically, when the potential is floating, the potential of the cover plate can be 0.6V-0.7V lower than the potential of the positive terminal, still much higher than the potential of the negative terminal, making corrosion of the cover plate less likely under normal operating conditions.

[0080] Continue to refer to Figure 3 The battery pack also includes a battery controller, which is used to determine whether there is a short circuit or open circuit in the micro-conductive circuit, and also to control the closing and opening of the switch.

[0081] Optionally, the battery controller is used to disconnect the switch in the micro-conducting circuit corresponding to cell b when an open circuit is detected in the micro-conducting circuit corresponding to cell a. Cell b includes at least one cell adjacent to cell a.

[0082] Here, since the micro-conductive circuit corresponding to cell a is open, this application embodiment does not limit whether the battery controller disconnects the switch in the micro-conductive circuit corresponding to cell a.

[0083] Among them, detecting the presence of a micro-conducting circuit open circuit corresponding to a battery cell (denoted as battery cell a) includes: determining the micro-conducting circuit open circuit corresponding to battery cell a when the voltage between the positive terminal and the cover plate of battery cell a is detected to be greater than, for example, a voltage threshold of 1 (e.g., 0.5V).

[0084] It's important to note that when the micro-conducting circuit corresponding to the battery cell is functioning normally (no short circuit or open circuit), this circuit can raise the potential of the cell's cover plate to equal the potential of the positive terminal. This means the voltage between the positive terminal and the cover plate should be 0V. If the voltage between the positive terminal and the cover plate exceeds a voltage threshold of 1 (e.g., 0.5V), it indicates an open circuit in the micro-conducting circuit, preventing it from raising the cover plate's potential to equal the positive terminal's potential. Therefore, the cover plate's potential is floating, resulting in a voltage greater than the voltage threshold of 1 (e.g., 0.5V) between it and the positive terminal.

[0085] It should be noted that the voltage threshold of 1 is a value greater than 0V; the aforementioned 0.5V is merely an example. In practice, other values ​​are possible, such as 0.3V, 0.4V, 0.6V, 0.7V, etc. This should not be construed as limiting the embodiments of this application.

[0086] Here, if an open circuit is detected in the micro-conductive circuit corresponding to cell a, the switch in the micro-conductive circuit corresponding to cell b is disconnected, for reasons including but not limited to the following two aspects.

[0087] On the one hand, the battery cells in the battery pack are densely packed. An abnormal voltage in any single cell (e.g., the voltage between the positive terminal and the cover plate of cell a exceeding the voltage threshold 1) is not an isolated event; it can affect surrounding cells through physical connections or electric field coupling, triggering a chain reaction of safety risks. Therefore, once a voltage abnormality is detected in a cell, at least its adjacent cells should be defensively protected (e.g., disconnecting the switch of the micro-conducting circuit corresponding to the adjacent cell) to prevent the fault from escalating. While micro-conducting circuits can prevent cell corrosion, they also introduce additional complexity. For example, when the battery controller detects an open circuit in the micro-conducting circuit corresponding to a cell, the micro-conducting circuits corresponding to adjacent cells may be at risk of short circuits. The safest approach is to disconnect the switch of the micro-conducting circuit corresponding to the adjacent cell, switching to a simple double-insulation state. Defensive protection is then provided for adjacent cells (e.g., cell b) of the cell with the abnormal voltage (e.g., cell a).

[0088] On the other hand, detecting an abnormal voltage in a battery cell could also be due to an abnormal operating condition causing the resistor in the micro-conducting circuit corresponding to cell a to break down under high voltage, or a wire in the micro-conducting circuit to break, resulting in an open circuit. This abnormal operating condition, while affecting cell a, may also affect cell b, which is adjacent to cell a. For example, it could cause the resistor in the micro-conducting circuit corresponding to cell b to break down under high voltage but not break down, forming a short circuit. Therefore, it is necessary to disconnect the switch in the micro-conducting circuit corresponding to cell b to defensively protect cell b.

[0089] Based on the foregoing, the battery pack also includes a battery controller.

[0090] The foregoing can also be understood as follows: the battery controller is used to, when the voltage between the cover plate and the positive terminal of one battery cell (e.g., the aforementioned battery cell a) is greater than or equal to a voltage threshold of 1, control the switch in the micro-conductive circuit corresponding to other battery cells (e.g., the aforementioned battery cell b) to be disconnected; the other battery cells include at least the battery cells adjacent to battery cell a among a plurality of battery cells. Optionally, the other battery cells here include all battery cells other than battery cell a among a plurality of battery cells.

[0091] Continue to refer to Figure 3 The battery pack also includes a voltage acquisition circuit. To save space and hardware costs associated with this circuit on the circuit board, it's not necessary to configure a separate voltage sampling circuit for each cell. Instead, multiple cells share a single voltage acquisition circuit. This circuit employs a time-sharing voltage acquisition mechanism, allowing it to collect the voltage between the positive terminal and the cover plate of different cells at different times, determining whether the micro-conductive circuit corresponding to each cell is open-circuited. For example, at time 1, the voltage acquisition circuit connects to connection points A1 and B2 corresponding to cell 1 to detect the voltage between the positive terminal and the cover plate. At time 2, the circuit connects to connection points A2 and B2 corresponding to cell 2 to detect the voltage between the positive terminal and the cover plate. Similarly, at time n, the circuit connects to connection points A(n) and B(n) corresponding to cell n to detect the voltage between the positive terminal and the cover plate. The battery controller obtains the voltage through the voltage acquisition circuit to determine if there is an open circuit in the micro-conductive circuit corresponding to any cell. If there is no open circuit in the micro-conductive circuit corresponding to the battery cell, the battery controller can control the voltage acquisition circuit to continue to collect voltage in a loop.

[0092] The battery controller is used to control the voltage sampling circuit to acquire voltage. The acquisition logic is recorded in the battery controller and used by the battery controller to control the voltage sampling circuit to acquire voltage. The following explanation uses the example of the battery controller controlling the voltage sampling circuit to acquire the voltage between the positive terminal and the cover plate of cell n.

[0093] like Figure 5As shown, the battery controller includes a microcontroller unit (MCU) and an analog front end (AFE). The voltage acquisition circuit includes an acquisition channel and two connection terminals, namely connection terminal 1 and connection terminal 2. The acquisition channel includes a filter, an analog-to-digital converter (ADC), and a level shifter.

[0094] See Figure 5 At point (1), the microcontroller in the battery controller writes control instructions to the configuration register in the analog front-end chip according to the acquisition logic. These control instructions can be used to indicate the objects to be connected at connection terminals 1 and 2. For example, selecting the positive terminal and cover plate of cell n.

[0095] After receiving the control command, the analog front-end chip drives connection terminals 1 and 2 to connect to connection points A(n) and B(n) respectively, in order to measure the voltage between the positive terminal and the cover plate of cell n. Thus, the measurement path is established.

[0096] See Figure 5 At point (2), the analog voltage signal of the cover plate and the analog voltage signal of the positive terminal are acquired through connection terminal 1 and connection terminal 2, respectively, and are first transmitted to a filter to filter out noise in the analog voltage signal. Then, the filtered analog voltage signal is transmitted to the analog-to-digital converter (ADC). The ADC is used to convert the continuous analog voltage signal into a digital voltage signal (representing the voltage between the positive terminal and the cover plate of cell n) that can be recognized and processed by the microcontroller. The level of the digital voltage signal output by the ADC may not match the level of the signal that the microcontroller's port can accept. The level converter can convert the digital voltage signal output by the ADC so that the level of the converted digital voltage signal matches the level of the signal that the microcontroller's port can accept, and can be read by the microcontroller more safely and reliably. Optionally, the level converter can write the converted digital voltage signal into a data register. Subsequently, the microcontroller can obtain the converted digital voltage signal (representing the voltage between the positive terminal and the cover plate of cell n) from the data register.

[0097] See Figure 5 As shown in (3), the microcontroller can determine whether the micro-conducting circuit corresponding to cell n is open by the voltage between the positive terminal and the cover plate of cell n. Optionally, in the case of an open circuit, the microcontroller can disconnect the switch in the micro-conducting circuit corresponding to cell 1-cell (n-1). In this case, cell n is an example of cell a mentioned above. Cell 1-cell (n-1) is an example of cell b mentioned above.

[0098] As described above, in the event of an open circuit in the micro-conducting circuit corresponding to a cell (denoted as cell a), the battery controller can control the switch in the micro-conducting circuit corresponding to cell b to disconnect. Cell b includes at least one cell adjacent to cell a. This allows for rapid isolation of potential risks and defensive protection of cell b. After isolating potential risks, the battery controller can also perform insulation detection to determine whether the insulation structure between cells has been damaged, resulting in insulation failure. Here, insulation failure can be a consequence of partial micro-conducting circuit abnormalities (open circuit or short circuit) or a cause of such abnormalities. Furthermore, when the micro-conducting circuit corresponding to a cell is disconnected and the cell is in a double-insulated state, the potential of the cell's cover plate is floating, neither pulled up by the positive terminal nor pulled down by the negative terminal. Under abnormal operating conditions such as insulation failure, the voltage of the cover plate is easily affected by external factors. For example, under abnormal operating conditions such as insulation failure, the potential of the cover plate can drop below the safe range, causing corrosion of the cover plate.

[0099] Therefore, if an open circuit exists in the micro-conducting circuit corresponding to a cell (denoted as cell a), the battery controller can perform insulation detection. If an insulation failure is detected between cells, the battery controller can report a warning message to the system controller, which can then disable the battery pack with the insulation failure to avoid a chain reaction caused by the insulation failure.

[0100] Optionally, the battery controller determines whether there is an insulation failure between two cells by measuring the cover voltage of the two cells. When the insulation between the two cells is normal, the cover voltage of the two cells equals voltage 1. When the insulation between the two cells fails, the cover voltage of the two cells is not equal to voltage 1 (it may be greater than or less than voltage 1). This voltage 1 is calculable and depends on the connection method of the cells in the battery pack. For a detailed description of voltage 1, please refer to the description of related content below; it will not be repeated here.

[0101] It should be noted that the two cells undergoing insulation testing may or may not include other cells. The switches in the corresponding micro-conductive circuits of the two cells undergoing insulation testing, as well as the cells between them, must be in the same state (e.g., both open or both closed); otherwise, the measurement results will be affected.

[0102] It should also be noted that normal insulation between two battery cells indicates that there is no insulation failure between the two cells. This can also be understood as the insulation between any two adjacent cells, and between the two cells in between, being normal. Insulation failure between two battery cells indicates that there is an insulation failure between the two cells. This can also be understood as the insulation failure between adjacent cells, and between the two cells in between.

[0103] Here, the two battery cells undergoing insulation testing are referred to as cell c and cell d. Cell c and cell d can be two of the aforementioned cells a and cell b, or they can be two cells other than cells a and cell b.

[0104] The battery controller sends a warning message 1 when the voltage between the cover plates of cells c and d is not equal to voltage 1. Warning message 1 indicates an insulation failure between cells c and d. In the case of cells connected in series in the battery pack, voltage 1 equals the sum of the cell voltages of the cells connected in series between cells c and d, plus the cell voltage of cell d. The potential of the positive terminal of cell d is higher than the potential of the positive terminal of cell c.

[0105] When the cells in the battery pack are connected in parallel, the cover plates of cell c and cell d have the same potential, so voltage 1 is 0V.

[0106] Specifically, the voltage between the cover plates of cells c and d is not equal to voltage 1, including situations where the voltage between the cover plates of cells c and d is greater than voltage 1, or the voltage between the cover plates of cells c and d is less than voltage 1. For example, when the cells in the battery pack are connected in series, if the cover plates of cells c and d short-circuit due to insulation failure, the voltage between the cover plates of cells c and d will be close to 0V. When the cells in the battery pack are connected in series or parallel, if the cover plate of cell c or d short-circuits with the battery pack casing due to insulation failure, the potential of the cover plate of cell c or d will be raised to a higher level, which may result in a voltage higher than voltage 1 between the cover plates of cells c and d.

[0107] In this embodiment of the application, A (e.g., the voltage between the cover plates of cell c and cell d) is not equal to B (e.g., voltage 1) means that the difference between A and B is large and not within a reasonable error range.

[0108] Optionally, cell c and cell d can be two adjacent cells. This allows for a more precise location of the insulation failure zone between two adjacent cells.

[0109] like Figure 6As shown, the battery controller can obtain the cover voltage of cells c and d through a voltage acquisition circuit. For example, when cells c and d are adjacent, they can be cells 1 and 2 respectively. In this case, cells c and d are in adjacent positions. The battery controller can then control the two terminals of the voltage acquisition circuit to connect to connection points A1 and A2 respectively to obtain the cover voltage of cells 1 and 2. As another example, when cells c and d are adjacent, they can also be cells 1 and 6 respectively. In this case, cells c and d are in adjacent rows. The battery controller can then control the two terminals of the voltage acquisition circuit to connect to connection points A1 and A6 respectively to obtain the cover voltage of cells 1 and 6. The process by which the battery controller obtains the cover voltage of cells c and d through the voltage acquisition circuit can be referred to the aforementioned... Figure 5 The description will not be repeated here.

[0110] Figure 6 The content herein should not be construed as limiting the embodiments of this application. For example, Figure 6 The example given uses six cells (cells 1-n), but in practice, there can be more or fewer cells. Furthermore, the arrangement of cells 1-n is not limited to... Figure 6 The diagram shows 2 rows and 3 columns.

[0111] It's important to note that when the battery cells in the battery pack are connected in series, the voltage 1 satisfies V1 = V11 + V12, taking into account the possibility of inconsistent cell voltages. If we assume that the cell voltages are uniform, then V1 = V11 + V12 can be expressed as V1 satisfying X + 1 times the cell voltage. Here, X is the number of cells connected in series between cell c and cell d, and X is greater than or equal to 0. Furthermore, if there are no other cells between cell c and cell d, then V11 equals 0.

[0112] It should also be noted that the switches in the micro-conducting circuits corresponding to each battery cell are closed by default. The aforementioned statement only closed the switches in the micro-conducting circuits corresponding to cell a and battery b. This means that when cells c and d are two cells from cell a and battery b, the switches in the micro-conducting circuits corresponding to cells c and d, as well as the cell between them, are all open. When cells c and d are two cells other than cell a and battery b, the switches in the micro-conducting circuits corresponding to cells c and d, as well as the cell between them, are all closed. This means that using the cover voltage of cells c and b to determine whether insulation has failed is reliable.

[0113] Based on the foregoing, insulation failure between battery cells can be either a consequence of partial micro-conductivity circuit abnormalities (open circuit or short circuit) or a cause of such abnormalities.

[0114] Therefore, optionally, the battery controller can also determine whether to disconnect the switches in the micro-conducting circuit through insulation detection. If an insulation failure is detected between two cells, the battery controller can disconnect the switches in the micro-conducting circuits corresponding to both cells and the cell between them. This is to prevent insulation failure from causing a short circuit in the micro-conducting circuit, resulting in localized overcurrent and overheating.

[0115] Here, the two cells undergoing insulation testing are denoted as cell e and cell f. Cell e and cell f are two cells in the battery pack.

[0116] The battery controller is also used to disconnect the switches in the micro-conducting circuits corresponding to cells e, f, and the cells between them when the voltage between the cover plates of cell e and cell f is not equal to voltage 2. When the cells in the battery pack are connected in series, voltage 2 equals the sum of the cell voltages of the cells connected in series between cells e and f, plus the cell voltage of cell f. The potential of the positive terminal of cell f is higher than the potential of the positive terminal of cell e.

[0117] When the cells in the battery pack are connected in parallel, the cover plates of cell e and cell f have the same potential, so voltage 2 is 0V.

[0118] Optionally, cell e and cell f can be two adjacent cells. This allows for a more precise location of the insulation failure zone between two adjacent cells.

[0119] Optionally, if the voltage between the cover plates of cell e and cell f is not equal to voltage 2, a warning message 2 can also be sent. Warning message 2 can be used to indicate an insulation failure between cell e and cell f.

[0120] In addition to cells e and f, the battery pack also includes cell g. When the switches in the micro-conductive circuits corresponding to cells e and f are disconnected, the battery controller is further configured to control the switches in the micro-conductive circuits corresponding to cell g to disconnect as well. Cell g includes at least one cell adjacent to cell e and / or cell f. This provides defensive protection for cell e experiencing voltage abnormalities and for cell f's adjacent cells.

[0121] The battery controller can obtain the cover voltages of cells e and f through a voltage acquisition circuit. This process can be referenced in the previous section. Figure 5 The description will not be repeated here.

[0122] Based on the foregoing, the battery pack may include a first cell and a second cell among its multiple cells. The switches in the micro-conducting circuits corresponding to the first cell, the second cell, and the cells in between are all either open or closed.

[0123] The battery controller sends a first warning message (or first message) when the voltage between the cover plates of the first and second cells is not equal to a first voltage. The first message indicates an insulation failure between the first and second cells. When multiple cells are connected in series, the first voltage satisfies: V1 = V11 + V12. Where V1 is the first voltage, V11 is the sum of the cell voltages of the cells connected in series between the first and second cells, and V12 is the cell voltage of the second cell. The potential of the positive terminal of the second cell is higher than that of the positive terminal of the first cell. When multiple cells are connected in parallel, the first voltage is 0V.

[0124] The cell controller is also used to stop charging and discharging the battery pack after sending the first message. This is to prevent further damage to the battery pack due to insulation failure during continued charging and discharging.

[0125] It's important to note that the battery controller can send a first message to the system controller to notify it of an insulation failure within the battery pack. Upon receiving this message, the system controller allocates the power of the faulty battery pack (with insulation failure) to other battery packs with intact insulation, and instructs the battery controller to stop charging and discharging the battery packs. This ensures that the power output and input of the energy storage system are not affected by the faulty battery pack.

[0126] When all switches in the micro-conductive circuits corresponding to the first cell, the second cell, and the cell between them are closed, and the voltage between the cover plate of the first cell and the cover plate of the second cell is not equal to the first voltage, the battery controller is also used to control the switches in the micro-conductive circuits corresponding to the first cell, the second cell, and the cell between them to open.

[0127] Here, an example of the first and second battery cells can be the aforementioned battery cells c and d. In this case, an example of the first message can be the aforementioned warning message 1. Another example of the first and second battery cells can be the aforementioned battery cells e and f. In this case, an example of the first message can be the aforementioned warning message 2.

[0128] Optionally, to more accurately locate cells with insulation failures, the first and second cells are arranged adjacent to each other. When multiple cells are arranged in multiple rows and columns, "adjacent" includes: the first and second cells being in the same row (e.g., the first and second cells are respectively...). Figure 6Cell 1 and Cell 2 in the battery cell, or, the first cell and the second cell are in the same column (e.g., the first cell and the second cell are respectively...). Figure 6 Cells 1 and 6 in the battery cell.

[0129] As can be seen from the foregoing, the voltage acquisition circuit in the battery pack provided in this application embodiment includes connection terminal 1 and connection terminal 2.

[0130] In this configuration, connection terminal 1 is used to connect to the cover plate of one battery cell. Connection terminal 2 is optionally used to connect to the positive terminal of that battery cell to obtain the voltage between the positive terminal of the battery cell and the cover plate; alternatively, connection terminal 2 is used to connect to the cover plate of another battery cell to obtain the voltage between the cover plates of one battery cell and the cover plate of another battery cell. The battery cell involved here can be the aforementioned battery cell a, battery cell c, or battery cell e. When one battery cell is battery c or battery e, the other battery cell can correspond to battery cell d or battery cell f.

[0131] The foregoing description uses a voltage acquisition circuit with two connection terminals as an example. In practice, a voltage acquisition circuit can have 2Y connection terminals, where Y is an integer greater than or equal to 1. When Y is greater than 1, it means that the battery acquisition circuit can simultaneously acquire voltages from more locations, thereby improving voltage detection efficiency. This application does not limit this aspect.

[0132] It should be noted here that... Figure 6 and Figure 3 The battery pack shown is compared to the aforementioned Figure 2 The battery packs shown contain components with the same names (e.g., power converters, battery modules) that have the same function, as described above. Figure 2 The description of the embodiments in this application will not be repeated here.

[0133] It should also be noted that the switch in the micro-conductive circuit can be a field-effect transistor (FET). Specifically, this FET can be a metal-oxide-semiconductor FET (MOSFET). In practical applications, besides FETs, the switch in the micro-conductive circuit can also be other switching components. For example, bipolar transistors, insulated-gate bipolar transistors, etc., are not limited to these in this application embodiment.

[0134] It should also be noted that the aforementioned integration of components such as the voltage acquisition circuit, battery controller, and micro-conducting circuit onto the same circuit board. In practice, the voltage acquisition circuit, battery controller, and micro-conducting circuit can be placed on two or more circuit boards. This application does not limit this. This application also does not limit the form of the circuit board. For example, the circuit board can be a printed circuit board (PCB). For example, it can be a flexible printed circuit board (FPCB), also known as a flexible board. It can also be a rigid printed circuit board (RPCB), also known as a rigid board.

[0135] This application also provides an energy storage system, such as... Figure 7 As shown, the energy storage system includes the battery pack provided in the embodiments of this application. The energy storage system also includes a DC bus, and the battery packs (e.g., battery pack 1 and battery pack 2) in the energy storage system are all connected to the DC bus to achieve charging and discharging through the DC bus.

[0136] Energy storage systems also include battery management systems that manage the battery pack. The controller within the battery management system that manages the battery pack can be called the system controller. Figure 7 (Not shown in the image).

[0137] The system controller is used to acquire warning messages that indicate an insulation failure between cells in the first battery pack. These warning messages can be the aforementioned warning message 1 or warning message 2.

[0138] The system controller is also used to control the first battery pack to stop supplying power to the DC bus and to control the first battery pack to stop drawing power from the DC bus.

[0139] It should be noted here that, compared to Figure 1 , Figure 7 Components with the same name (e.g., power converters, inverters, etc.) have the same function; please refer to the aforementioned section for details. Figure 1 The description will not be repeated here.

[0140] about Figure 7 For a description of the battery pack, please refer to the previous section. Figure 3 , Figure 6 The description of the relevant content will not be repeated here.

[0141] The various embodiments of this application can be combined arbitrarily to achieve different technical effects.

[0142] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0143] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

[0144] In summary, the above description is merely an embodiment of the technical solution of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made based on the disclosure of this application should be included within the scope of protection of this application.

Claims

1. A battery pack, characterized in that, The battery pack includes multiple battery cells and multiple micro-conducting circuits, with each of the multiple battery cells and the multiple micro-conducting circuits corresponding to and connected to each other. Each of the battery cells includes a positive terminal, a negative terminal, a housing, and a cover plate. The cover plate is disposed on the housing, and the positive terminal and the negative terminal pass through the cover plate. An insulating structure is provided between the negative terminal and the cover plate. The micro-conductive circuit corresponding to the battery cell is connected between the positive terminal of the battery cell and the cover plate of the battery cell, and the micro-conductive circuit corresponding to the battery cell includes a resistor.

2. The battery pack according to claim 1, characterized in that, An insulating structure is provided between the positive electrode post and the cover plate.

3. The battery pack according to claim 1 or 2, characterized in that, The micro-conducting circuit corresponding to the battery cell also includes a switch, which is connected in series with the resistor. When the switch is closed, the positive terminal of the battery cell is connected to the cover plate of the battery cell through the micro-conductive circuit, thereby increasing the potential of the cover plate. The switch is turned off to insulate the positive terminal and cover plate of the battery cell.

4. The battery pack according to claim 3, characterized in that, The battery pack also includes a battery controller. The battery controller is used to control the switches in the micro-conducting circuits corresponding to other cells to disconnect when the voltage between the cover plate and the positive terminal of one cell is greater than or equal to a first voltage threshold; the other cells include at least one cell that is adjacent to the first cell among the plurality of cells.

5. The battery pack according to claim 4, characterized in that, The other battery cells include all battery cells other than the one mentioned above.

6. The battery pack according to any one of claims 3-5, characterized in that, The plurality of battery cells includes a first battery cell and a second battery cell, and the switches in the micro-conducting circuits corresponding to the first battery cell, the second battery cell, and the battery cells between them are all either open or closed; The battery controller is configured to send a first message when the voltage between the cover plate of the first cell and the cover plate of the second cell is not equal to a first voltage. The first message indicates an insulation failure between the first cell and the second cell. When the multiple cells are connected in series, the first voltage satisfies: V1 = V11 + V12, where V1 is the first voltage, V11 is the sum of the cell voltages of the cells connected in series between the first cell and the second cell, and V12 is the cell voltage of the second cell. The potential of the positive terminal of the second cell is higher than the potential of the positive terminal of the first cell.

7. The battery pack according to claim 6, characterized in that, When all switches in the micro-conductive circuits corresponding to the first battery cell, the second battery cell, and the battery cell between them are closed, and the voltage between the cover plates of the first battery cell and the second battery cell is not equal to the first voltage, The battery controller is also used to control the switches in the micro-conducting circuits corresponding to the first cell, the second cell, and the cell between them to disconnect.

8. The battery pack according to claim 6 or 7, characterized in that, The first battery cell and the second battery cell are arranged adjacent to each other.

9. The battery pack according to claim 8, characterized in that, The plurality of battery cells are arranged in multiple rows and columns, and the adjacent arrangement includes the first battery cell and the second battery cell being in the same row, or the first battery cell and the second battery cell being in the same column.

10. The battery pack according to any one of claims 1-9, characterized in that, The battery pack also includes a voltage acquisition circuit, which includes a first terminal and a second terminal; The first end is used to connect to the cover plate of a battery cell; the second end is used to connect to the positive terminal of the battery cell to obtain the voltage between the positive terminal of the battery cell and the cover plate, or the second end is used to connect to the cover plate of another battery cell to obtain the voltage between the cover plate of one battery cell and the cover plate of another battery cell.

11. An energy storage system, characterized in that, The energy storage system includes a battery pack as described in any one of claims 1-10; the energy storage system also includes a DC bus, and all battery packs in the energy storage system are connected to the DC bus.

12. The energy storage system according to claim 11, characterized in that, The energy storage system also includes a system controller; The system controller is used to acquire a second message, the second message being used to indicate that there is an insulation failure between cells in the first battery pack; The system controller is also configured to control the first battery pack to stop supplying power to the DC bus, and to control the first battery pack to stop receiving power from the DC bus.

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