A battery pack dynamic parallel connection method

Abstract

The application discloses a kind of battery pack dynamic parallel connection methods.The method includes determining first battery pack according to the voltage and state of charge of each battery pack in energy storage equipment;Determine the second battery pack;Wherein, the second battery pack is the remaining battery pack except the first battery pack in the energy storage equipment;The difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than the maximum state of charge threshold value set in advance;Parallel connection strategy is executed to the first battery pack and the second battery pack, to realize the dynamic parallel connection of the first battery pack and the second battery pack;Wherein, the parallel connection strategy is on-off control to battery pack charging switch and discharging switch.This technical solution can realize the dynamic parallel connection of battery pack, effectively avoid circulating current and current impact, ensure the uninterrupted operation of energy storage equipment power supply, significantly improve the product use flexibility and intelligent experience.

Description

Technical Field

[0001] This invention relates to the field of battery pack parallel operation technology, and more particularly to a method for dynamic parallel operation of battery packs. Background Technology

[0002] With the rapid popularization of portable energy storage devices, the demand for large-capacity expansion continues to increase while meeting portability requirements. As a result, the technical solution of expanding capacity by connecting multiple battery packs in parallel with cables has been widely adopted.

[0003] The existing parallel expansion scheme adopts a static parallel mode, which can only connect the new expansion battery pack in the standby state when the charging input is disconnected and the discharge output is turned off, so as to suppress the circulating current generated in the parallel branch and ensure the stable operation of the system.

[0004] This solution is limited by the control architecture and does not support hot-swapping and parallel operation. If a user plugs in an additional capacity battery pack while the device is charging or discharging, the additional battery pack cannot be connected to the charging / discharging circuit to participate in the operation. This not only necessitates power outages for capacity expansion during emergency power supply, preventing uninterrupted battery life, but also misleads users into believing the device has malfunctioned, significantly reducing the product experience. Summary of the Invention

[0005] This invention provides a method for dynamic parallel operation of battery packs, which can realize dynamic parallel operation of battery packs, effectively avoid circulating current and current surges, ensure uninterrupted power supply to energy storage devices, and significantly improve the flexibility and intelligent experience of product use.

[0006] According to one aspect of the present invention, a method for dynamic parallel operation of a battery pack is provided, the method comprising: The first battery pack is determined based on the voltage and state of charge of each battery pack in the energy storage device; A second battery pack is identified; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold. A parallel operation strategy is implemented for the first battery pack and the second battery pack to achieve dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the charging switch and the discharging switch of the battery pack.

[0007] According to another aspect of the present invention, a battery pack dynamic parallel operation device is provided, the device comprising: The first battery pack determination module is used to determine the first battery pack based on the voltage and state of charge of each battery pack in the energy storage device. The second battery pack determination module is used to determine the second battery pack; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold. A dynamic parallel operation module is used to execute a parallel operation strategy on the first battery pack and the second battery pack to achieve dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the battery pack charging switch and discharging switch.

[0008] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform a battery pack dynamic parallel operation method according to any embodiment of the present invention.

[0009] According to another aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing computer instructions for causing a processor to execute and implement a battery pack dynamic parallel operation method according to any embodiment of the present invention.

[0010] According to another aspect of the present invention, an energy storage device is provided, including an energy storage device program, which, when executed by a processor, implements a dynamic parallel operation method for a battery pack as described in any embodiment of the present invention.

[0011] The technical solution of this invention determines a first battery pack based on the voltage and state of charge of each battery pack in the energy storage device; then determines a second battery pack; and executes a parallel operation strategy on the first and second battery packs to achieve dynamic parallel operation of the first and second battery packs. This technical solution enables dynamic parallel operation of battery packs, effectively avoids circulating current and current surges, ensures uninterrupted power supply to the energy storage device, and significantly improves product flexibility and intelligent experience. It solves the pain point of existing static parallel operation solutions that only allow for capacity expansion during shutdown and cannot perform online hot-swappable capacity expansion.

[0012] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a flowchart of a dynamic parallel operation method for a battery pack according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a dynamic parallel operation method for a battery pack provided in Embodiment 2 of the present invention; Figure 3 This is a flowchart of the first strategy provided in Embodiment 2 of this application; Figure 4 This is a flowchart of a dynamic parallel operation process for a battery pack provided in Embodiment 3 of the present invention; Figure 5 This is a flowchart of the second strategy provided in Embodiment 3 of this application; Figure 6 This is a schematic diagram of a dynamic parallel operation process of a battery pack provided in Embodiment 4 of the present invention; Figure 7 This is a flowchart of the parallel control provided in Embodiment 4 of this application; Figure 8 This is a flowchart of the discharge process provided in Embodiment 4 of this application; Figure 9 This is a flowchart of the charging process provided in Embodiment 4 of this application; Figure 10 This is a flowchart of the power flow discharge processing provided in Embodiment 4 of this application; Figure 11 This is a flowchart of the power charging process provided in Embodiment 4 of this application; Figure 12 This is a schematic diagram of another dynamic parallel operation process of a battery pack provided in Embodiment 5 of the present invention; Figure 13 This is a schematic diagram of another dynamic parallel operation process of a battery pack provided in Embodiment Six of the present invention; Figure 14 This is a structural diagram of the energy storage device provided in Embodiment Six of this application; Figure 15 This is a schematic diagram of the parallel cable interface provided in Embodiment Six of this application; Figure 16 This is a schematic diagram of a battery pack dynamic parallel operation device provided in Embodiment 7 of the present invention; Figure 17 This is a schematic diagram of the structure of an electronic device that implements a dynamic parallel operation method for a battery pack according to an embodiment of the present invention. Detailed Implementation

[0015] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0016] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0017] Example 1 Figure 1 This is a flowchart of a dynamic parallel operation method for battery packs according to Embodiment 1 of the present invention. This embodiment is applicable to situations involving dynamic parallel operation of battery packs. The method can be executed by a dynamic parallel operation device for battery packs, which can be implemented in hardware and / or software and can be configured in a device. For example, the device can be a backend server or other device with communication and computing capabilities. Figure 1 As shown, the method includes: S110. Determine the first battery pack based on the voltage and state of charge of each battery pack in the energy storage device.

[0018] In this embodiment, the energy storage device refers to a device that efficiently stores external electrical energy in an internal energy unit through batteries, capacitors, or other means, and outputs stable power when needed through inverters, power management, and other technical units. This device features high energy density, portability, and multi-interface compatibility, providing reliable power support for various scenarios such as camping, emergency rescue, mobile operations, and field photography, thus addressing temporary power supply needs in environments without or without electricity.

[0019] In this scheme, the energy storage device is composed of multiple battery packs; a single battery pack is configured as the main control battery pack (main pack), which undertakes the functions of overall control and core power supply; the remaining battery packs are expansion battery packs (power-up packs), and all expansion battery packs work in parallel with the main control battery pack.

[0020] The main control battery pack is composed of core components such as a main control board, a BMS (Battery Management System) board, energy storage batteries, and an inverter. The main control board is the overall control unit of the entire system, coordinating the entire process control logic, including charging and discharging strategy management, human-machine interaction, and cloud platform communication. The BMS board is responsible for battery status monitoring and operation data acquisition, is controlled by the main control board, and has independent priority battery safety protection permissions. The energy storage battery is the core energy carrier of the energy storage device, relying on the charging and discharging MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) integrated on the BMS board to complete the charging and discharging of electrical energy. The inverter is used to execute the control commands issued by the main control board to realize AC charging and AC external discharge. Existing models of inverters generally integrate photovoltaic (PV) charging functions.

[0021] In this embodiment, the expanded battery pack cannot complete charging and discharging independently. It needs to rely on the main control battery pack to achieve energy charging and discharging, and it also has independent safety protection permissions.

[0022] Furthermore, in two scenarios—power-on initialization of the expanded battery pack and disconnection from the main control battery pack—the charging and discharging MOSFETs will quickly cut off the circuit. The main control battery pack's main control board can issue control commands to orderly manage the on / off state of the expanded battery pack's charging and discharging MOSFETs, thereby completing the unified management of the charging and discharging of each expanded battery pack.

[0023] In this scheme, voltage refers to the total voltage output across the positive and negative terminals of the battery pack.

[0024] In this embodiment, the state of charge refers to the percentage of the battery's current remaining usable capacity relative to its rated total capacity.

[0025] Specifically, each battery pack BMS collects the voltage of the battery pack through a voltage divider sampling circuit and uploads the voltage to the main control battery pack main control board.

[0026] Furthermore, each battery pack BMS calculates the state of charge in real time based on multi-dimensional parameters such as voltage, charging and discharging current, cell temperature, and cumulative charging and discharging amount, combined with the built-in power algorithm, and uploads the state of charge to the main control battery pack main control board.

[0027] In this embodiment, the first battery pack can be either the main control battery pack or the expansion battery pack.

[0028] Specifically, the main control board compares the voltage and state of charge of all battery packs in the energy storage device to select the first battery pack from multiple battery packs. The selection logic includes the following: The battery pack with the lowest voltage is selected as the first battery pack; or the battery pack with the lowest state of charge is selected as the first battery pack; or the state of charge difference between the battery pack with the lowest voltage and the battery pack with the lowest state of charge is compared, and one of the two is selected as the first battery pack.

[0029] The battery pack with the highest voltage is selected as the first battery pack; or the battery pack with the largest state of charge is selected as the first battery pack; or the state of charge difference between the battery pack with the highest voltage and the battery pack with the largest state of charge is compared, and one of the two is selected as the first battery pack.

[0030] S120. Determine the second battery pack; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold.

[0031] In this embodiment, the maximum state of charge threshold is a preset parameter. For example, the maximum state of charge threshold can be set to 50%. The value of this threshold is directly related to the battery specifications, cell internal resistance, and parallel line impedance. It needs to be determined by theoretical calculation and actual measurement calibration of the whole machine, in conjunction with the cell characteristic parameters and matching parallel cable impedance parameters provided by the battery manufacturer.

[0032] The maximum state of charge (SOC) threshold is used to limit the maximum permissible SOC difference between synchronously charging and discharging battery packs. When the SOC difference is within this threshold, the circulating current generated in parallel will not damage the cells and power distribution lines. This rule is the SOC difference control principle for parallel battery packs in this scheme. The energy storage device constrains the SOC difference between all synchronously charging and discharging battery packs to not exceed this maximum SOC threshold. If it exceeds the maximum SOC threshold, the charging and discharging MOSFETs of the corresponding battery pack are turned off, temporarily removing it from the charging and discharging circuit.

[0033] In this scheme, after the main control board selects the first battery pack, it selects the second battery pack from the remaining battery packs based on the state of charge of the first battery pack and the state of charge of the remaining battery packs in the energy storage device.

[0034] Specifically, battery packs whose state of charge (SOC) difference from that of the first battery pack is less than the maximum SOC threshold are identified as the second battery pack.

[0035] S130. Execute a parallel operation strategy on the first battery pack and the second battery pack to achieve dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the battery pack charging switch and discharging switch.

[0036] In this embodiment, the charging switch uses a charging MOSFET to control the on / off state of the charging circuit, and the discharging switch uses a discharging MOSFET to control the on / off state of the discharging circuit.

[0037] In this solution, the parallel operation strategy involves controlling the on / off state of the battery pack's charging and discharging switches. Exemplary parallel operation strategies fall into two categories: controlling the charging switch of the first battery pack to be open and the discharging switch to be closed; controlling the charging switch of the second battery pack to be closed and the discharging switch to be open; controlling the charging switch of the first battery pack to be closed; and controlling the discharging switch of the second battery pack to be closed when charging current is detected. Alternatively, controlling the charging switch of the second battery pack to be open and the discharging switch to be closed; controlling the charging switch of the first battery pack to be closed and the discharging switch to be closed; and controlling the charging switch of the second battery pack to be closed when discharging current is detected.

[0038] Specifically, the main control board executes a preset parallel operation strategy for the selected first and second battery packs. By time-sharing control of the on / off states of the charging and discharging switches of the first and second battery packs, it balances the voltage and state of charge differences between the battery packs, suppresses the circulating current impact of the parallel circuit, and smoothly completes the dynamic connection between the first and second battery packs, realizing the online parallel operation of multiple battery packs.

[0039] The technical solution of this invention determines a first battery pack based on the voltage and state of charge of each battery pack in the energy storage device; then determines a second battery pack; and executes a parallel operation strategy on the first and second battery packs to achieve dynamic parallel operation of the first and second battery packs. By implementing this technical solution, dynamic parallel operation of battery packs can be achieved, effectively avoiding circulating current and current surges, ensuring uninterrupted power supply to the energy storage device, and significantly improving the flexibility and intelligent experience of product use.

[0040] Example 2 Figure 2 This is a schematic diagram of a dynamic parallel operation method for a battery pack according to Embodiment 2 of the present invention. The relationship between this embodiment and the above embodiments is a detailed description of the dynamic parallel operation process of the battery pack under charging conditions. Figure 2 As shown, the method includes: S210. Obtain the third battery pack and the fourth battery pack; wherein the third battery pack is the battery pack with the lowest voltage in the energy storage device; and the fourth battery pack is the battery pack with the lowest state of charge in the energy storage device.

[0041] In this scheme, during the dynamic parallel operation of the battery pack under charging conditions, all charging and discharging path switching is carried out in an orderly step-by-step manner under the control of the main control board. This control method avoids the circulation current generated by the parallel branches.

[0042] Among them, the third battery pack has the lowest voltage in the energy storage device; the fourth battery pack has the lowest state of charge in the energy storage device.

[0043] In this embodiment, the main control board collects the voltage and state of charge of all battery packs, and selects the third and fourth battery packs from multiple battery packs based on the collected voltage and state of charge.

[0044] S220. Determine whether the state of charge of the third battery pack is greater than the state of charge of the fourth battery pack, and whether the difference between the state of charge of the third battery pack and the state of charge of the fourth battery pack is greater than a preset maximum state of charge threshold.

[0045] Specifically, Figure 3 The first strategy flowchart provided for Embodiment 2 of this application is as follows: Figure 3 As shown, the device address of the priority charging battery pack is first determined. The core selection principle is that the battery pack with the lowest voltage has charging priority, which is the basic constraint for orderly charging. By first charging the low-voltage battery pack and then sequentially charging the other battery packs after its voltage rises, circulating current in parallel branches can be effectively suppressed. The main control board traverses all battery packs and selects the battery pack with the lowest total voltage that is allowed to be charged as the third battery pack, marking its device address as... And set this address as the priority charging address for the battery pack.

[0046] In this embodiment, as Figure 3 As shown, the address of the priority charging battery pack is corrected and verified. The system checks if the corresponding battery pack is indeed low on charge. The main control board iterates through all battery packs, selecting the one with the lowest state of charge that meets the charging permission conditions as the fourth battery pack, and marks its device address as [address missing]. .

[0047] Furthermore, such as Figure 3 As shown, the main control board will The corresponding state of charge of the third battery pack and The state of charge (SOC) of the third battery pack is compared with that of the fourth battery pack. It is determined whether the SOC of the third battery pack is greater than that of the fourth battery pack, and whether the difference between the SOC of the third battery pack and the SOC of the fourth battery pack is greater than a preset maximum SOC threshold.

[0048] S230. If so, the fourth battery pack is identified as the first battery pack.

[0049] In this plan, such as Figure 3 As shown, if the state of charge (SOC) of the third battery pack is greater than that of the fourth battery pack, and the difference between the SOCs of the third and fourth battery packs is greater than a preset maximum SOC threshold, then the address of the priority charging battery pack will be updated to [the specified value]. The fourth battery pack will be designated as the first battery pack.

[0050] S240. If not, then the third battery pack is identified as the first battery pack.

[0051] In this embodiment, as Figure 3 As shown, if the state of charge of the third battery pack is less than or equal to the state of charge of the fourth battery pack, and / or the difference between the state of charge of the third battery pack and the state of charge of the fourth battery pack is less than or equal to the preset maximum state of charge threshold, then the third battery pack is determined as the first battery pack.

[0052] In this scheme, relying solely on voltage to prioritize charging the battery pack has significant drawbacks. A low battery voltage does not necessarily indicate a low state of charge (SOC). When the battery pack is undergoing or has just completed a high-current discharge, the terminal voltage will temporarily drop due to the voltage drop caused by internal resistance. The actual SOC may still be at a relatively high level, a situation typical of photovoltaic energy storage scenarios. When the photovoltaic input power is weak and the battery pack is continuously discharging at a high current, a new battery pack is immediately connected after the discharge is cut off to perform dynamic parallel operation, and the energy storage device will activate its parallel operation strategy. The battery pack that previously underwent discharge has a high SOC, but its voltage is temporarily low due to the high-current voltage drop; the newly connected battery pack has an even lower SOC, and its open-circuit voltage is actually higher due to the lack of load voltage drop after long-term idling.

[0053] If the priority charging battery pack address correction step is omitted, the energy storage device will directly select the battery pack with the lowest voltage as the priority charging target. When there is a battery pack with a lower state of charge (SOC), and the difference between the two SOCs exceeds the preset maximum SOC threshold, the low-SOC battery pack will be blocked from charging according to the parallel SOC difference control rules. As the initially selected battery pack continues to charge, the SOC difference between the two continues to widen until the low-SOC battery pack is fully charged. The low-SOC battery pack will never be able to participate in charging, causing the equalization logic to fail.

[0054] After adding a priority charging battery pack address correction process, the energy storage device will prioritize charging the battery pack with the lowest state of charge (SOC). Battery packs with the lowest voltage but higher SOC will temporarily stop charging due to an excessive SOC difference. Once the priority charging battery pack has been charging for a period and its SOC has increased, the SOC difference between the two will fall back below the threshold. The main control board will then reactivate the charging switch of that battery pack, integrating it into the charging circuit. Ultimately, all battery packs can be fully charged, ensuring balanced charging performance for multi-pack energy storage devices.

[0055] S250. Determine the second battery pack; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold.

[0056] S260. A parallel operation strategy is executed on the first battery pack and the second battery pack to achieve dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the battery pack charging switch and discharging switch.

[0057] Optionally, the parallel operation strategy includes a first strategy; executing the first strategy on the first battery pack and the second battery pack includes: Control the charging switch of the first battery pack to open and the discharging switch to close; Controls the closing of the charging switch and the opening of the discharging switch of the second battery pack; Control the charging switch of the first battery pack to close; When the charging current of the second battery pack is detected, the discharge switch of the second battery pack is controlled to close.

[0058] In this scheme, the first strategy is to control the on / off state of the battery pack charging switch and discharging switch during charging.

[0059] In this embodiment, the differential voltage signal of the sampling resistor in the charging and discharging circuit of the second battery pack is collected in real time by the BMS, and the polarized circuit current is calculated. When the current polarity is the charging direction flowing from the bus to the second battery pack, and the current amplitude is greater than a preset minimum charging current threshold, it is determined that the charging current of the second battery pack has been detected. Specifically, as shown... Figure 3 As shown, the control flow of the first strategy is as follows: The main control board controls the charging switch of the first battery pack to be turned off; if the first battery pack has a discharging function, its discharging switch is turned on simultaneously.

[0060] For the second battery pack, if the battery pack meets the charging permission conditions, the main control board turns on its charging switch and turns off its discharging switch, putting it into a standby charging state; if the charging permission conditions are not met, the charging switch and the discharging switch are turned off simultaneously.

[0061] The main control board then turns on the charging switch of the first battery pack, keeping the terminal voltage of the first battery pack at the same potential as the bus voltage, and performs priority charging on the first battery pack.

[0062] As the first battery pack continues to charge, its state of charge gradually increases, and its terminal voltage rises synchronously. The second battery pack, which is in a standby state, is isolated by the voltage difference of its body diode and does not participate in charging in the initial stage. When the voltage of the first battery pack rises, driving up the bus voltage, and the bus voltage can output an effective charging current to the second battery pack, the BMS built into the second battery pack automatically turns on its own discharge switch, completing parallel operation and charging and discharging synchronously with the first battery pack. The branch current no longer passes through the body diode.

[0063] If any battery pack other than the first and second battery packs meets the charging permission conditions, but its own state of charge (SOC) is too high and the difference between its SOC and that of the first battery pack exceeds the preset maximum SOC threshold, then both the charging switch and the discharging switch will remain open. Once the SOC difference between the battery pack and the first battery pack falls back to within the threshold range, the main control board will turn on its charging switch, allowing it to connect to the charging circuit while keeping the discharging switch open. When the bus voltage rises to a level sufficient to generate charging current, the battery pack's own BMS will automatically turn on its discharging switch to complete parallel operation, and it will charge and discharge synchronously with the first and second battery packs.

[0064] Among them, the charging permission conditions refer to the criteria for determining whether the various state parameters of the battery pack meet the safe charging standards and allow the closed charging MOSFET to perform charging.

[0065] By controlling the charging and discharging switch conduction sequence of the priority charging battery pack and the battery pack to be charged in stages, and connecting the remaining battery packs in batches according to the maximum state of charge threshold, dynamic parallel operation of multiple battery packs can be achieved. This can significantly suppress the inrush circulating current during parallel connection, protect power switching devices and cells, and naturally form a charging circuit based on the bus voltage difference, eliminating the need for additional pre-charging hardware and reducing the overall cost. At the same time, the parallel operation is completed by the local BMS of each battery pack automatically controlling the on and off switches, achieving balanced and orderly charging of multiple battery packs, reducing the voltage difference and capacity difference between battery packs, and reducing the heat loss caused by continuous current in the body diode. This improves the charging efficiency and operational reliability of the energy storage equipment and extends the service life of the entire energy storage equipment.

[0066] The technical solution of this invention involves acquiring a third battery pack and a fourth battery pack; determining whether the state of charge (SOC) of the third battery pack is greater than that of the fourth battery pack, and whether the difference between the SOCs of the third and fourth battery packs is greater than a preset maximum SOC threshold; if so, the fourth battery pack is designated as the first battery pack; if not, the third battery pack is designated as the first battery pack; then, a second battery pack is determined; and a parallel operation strategy is implemented for the first and second battery packs to achieve dynamic parallel operation. By implementing this technical solution, a dual verification mechanism of voltage and SOC is used to correct charging priority, effectively avoiding the defects caused by relying solely on terminal voltage to select the priority charging battery pack, which leads to a continuous widening of the SOC difference between battery packs and the inability of low-capacity battery packs to access the charging circuit for a long time. This ensures that charging resources are continuously tilted towards the low-capacity battery packs, improving the balanced charging performance and operational stability of the energy storage device.

[0067] Example 3 Figure 4 This is a flowchart illustrating a dynamic parallel operation process of a battery pack according to Embodiment 3 of the present invention. The relationship between this embodiment and the previous embodiments is a detailed description of the dynamic parallel operation process of the battery pack under discharge conditions. Figure 4 As shown, the method includes: S410. Obtain the fifth battery pack and the sixth battery pack; wherein, the fifth battery pack is the battery pack with the highest voltage in the energy storage device; and the sixth battery pack is the battery pack with the largest state of charge in the energy storage device.

[0068] In this scheme, during the dynamic parallel operation of the battery pack under discharge conditions, all charging and discharging path switching is carried out in an orderly step-by-step manner under the control of the main control board. This control method avoids the circulation current generated in the parallel branches.

[0069] Among them, the fifth battery pack has the highest voltage in the energy storage device; the sixth battery pack has the largest state of charge in the energy storage device.

[0070] In this embodiment, the main control board collects the voltage and state of charge of all battery packs in the energy storage device, and selects the fifth and sixth battery packs from multiple battery packs based on the collected voltage and state of charge.

[0071] S420. Determine whether the state of charge of the fifth battery pack is less than the state of charge of the sixth battery pack, and whether the difference between the state of charge of the fifth battery pack and the state of charge of the sixth battery pack is greater than a preset maximum state of charge threshold.

[0072] In this plan, Figure 5 The second strategy flowchart provided in Embodiment 3 of this application is as follows: Figure 5As shown, the address of the priority discharge battery pack is first determined. The basic control principle of orderly discharge is to select the battery pack with the highest voltage for priority discharge. By discharging the high-voltage battery pack first to reduce its own voltage, the remaining battery packs are then connected in sequence to participate in the discharge, thereby avoiding parallel circulating current. The main control board traverses all battery packs and selects the battery pack with the highest voltage that meets the discharge permission conditions as the fifth battery pack, marking its address as [address missing]. This address will be temporarily designated as the priority discharge address for the battery pack.

[0073] In this embodiment, as Figure 5 As shown, the address of the priority discharge battery pack is corrected and verified. Check if the corresponding battery pack is the one with the highest actual capacity. The main control board then iterates through all battery packs again, selecting the battery pack with the highest state of charge and allowed to discharge as the sixth battery pack, and marking its address as [address missing]. .

[0074] Furthermore, such as Figure 5 As shown, The corresponding state of charge of the fifth battery pack and The state of charge (SOC) of the sixth battery pack is compared. It is determined whether the SOC of the fifth battery pack is less than that of the sixth battery pack, and whether the difference between the SOCs of the fifth and sixth battery packs is greater than a preset maximum SOC threshold.

[0075] S430. If so, the sixth battery pack is identified as the first battery pack.

[0076] In this plan, such as Figure 5 As shown, if the state of charge (SOC) of the fifth battery pack is less than that of the sixth battery pack, and the difference between the SOCs of the fifth and sixth battery packs is greater than a preset maximum SOC threshold, then the address of the battery pack to be discharged first will be updated. The sixth battery pack will be designated as the first battery pack.

[0077] S440. If not, then the fifth battery pack is identified as the first battery pack.

[0078] In this embodiment, as Figure 5 As shown, if the state of charge of the fifth battery pack is greater than or equal to the state of charge of the sixth battery pack, and / or the difference between the state of charge of the fifth battery pack and the state of charge of the sixth battery pack is less than or equal to the preset maximum state of charge threshold, then the fifth battery pack is determined as the first battery pack.

[0079] In this scheme, relying solely on battery terminal voltage to determine discharge priority has significant drawbacks; a higher battery terminal voltage does not necessarily indicate a higher state of charge (SOC). When the battery pack is undergoing high-current charging or has just finished high-current charging, the terminal voltage may appear artificially high due to charging polarization effects, but the actual SOC remains in a low range. This condition is particularly prominent in high-power energy storage scenarios. Under high-power charging conditions, the battery pack continuously charges with a high current. If a new battery pack is immediately connected after disconnecting the charging equipment to perform dynamic parallel operation, the energy storage equipment will trigger the parallel operation strategy. The battery pack that was previously charging has a low SOC, and its voltage is temporarily raised due to charging polarization; the newly connected battery pack has a higher SOC, and because it has been idle for a long time without polarization voltage drop, its open-circuit voltage is actually lower.

[0080] If the priority discharge battery pack address correction step is omitted, the energy storage device will directly select the battery pack with the highest terminal voltage as the priority discharge target. When there is a battery pack with a higher state of charge (SOC) value, and the difference between the two SOC values ​​exceeds the preset maximum SOC threshold, the high SOC battery pack will be blocked from discharging according to the parallel SOC difference constraint rule. As the initially selected battery pack continues to discharge, the SOC difference between the two continues to widen until the battery pack is completely discharged. The high SOC battery pack will never be able to connect to the discharge circuit, causing the discharge equalization logic to fail.

[0081] After adding a priority discharge battery pack address correction process, the energy storage device will update the battery pack with the highest state of charge as the priority discharge target. The battery pack with the highest original voltage but a low state of charge will temporarily stop discharging because the state of charge difference exceeds the limit. After the priority discharge battery pack discharges for a period of time and the state of charge drops, the state of charge difference between the two will be reduced to within the threshold range. The main control board will then re-turn on the discharge switch of the battery pack to rejoin the discharge circuit. In the end, all battery packs can be completely discharged, ensuring the balanced discharge performance of multi-battery pack energy storage devices.

[0082] S450. Determine the second battery pack; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold.

[0083] S460. Execute a parallel operation strategy on the first battery pack and the second battery pack to achieve dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the battery pack charging switch and discharging switch.

[0084] Optionally, the parallel operation strategy includes a second strategy, which is executed on the first battery pack and the second battery pack, including: Controls the charging switch of the second battery pack to open and the discharging switch to close; Control the closing of the charging switch and the discharging switch of the first battery pack; When the discharge current of the second battery pack is detected, the charging switch of the second battery pack is closed.

[0085] In this scheme, the second strategy is to control the on / off state of the battery pack charging switch and discharging switch under discharge conditions.

[0086] In this embodiment, the differential voltage signal of the sampling resistor of the charging and discharging circuit of the second battery pack is collected in real time by the BMS, and the polarized circuit current is calculated. When the current polarity is the discharge direction of the second battery pack flowing out of the bus, and the current amplitude is greater than the preset minimum discharge current threshold, it is determined that the discharge current of the second battery pack is detected.

[0087] Specifically, such as Figure 5 As shown, the control flow of the second strategy is as follows: The main control board disconnects the charging switches of all battery packs except the first battery pack; for the second battery pack that meets the discharge permission conditions and whose state of charge difference with the first battery pack is less than the preset maximum state of charge threshold, its discharge switch is turned on to put it into the standby state; for the other battery packs that do not meet the conditions, the charging switch and discharge switch remain off.

[0088] The main control board turns on the charging and discharging switches of the first battery pack, so that the terminal voltage of the battery pack is at the same potential as the bus voltage, and performs priority discharge on the first battery pack.

[0089] During the continuous discharge of the first battery pack, its state of charge gradually decreases, and its terminal voltage decreases synchronously. The second battery pack, due to the body diode voltage difference between its own terminal voltage and the bus voltage, will not initially participate in preferential discharge. Once the voltage of the first battery pack decreases, causing the bus voltage to decrease synchronously, and the bus voltage difference allows the second battery pack to generate an effective discharge current, the corresponding BMS built into the second battery pack automatically turns on its own charging switch, completing parallel operation and synchronously charging and discharging with the first battery pack. The branch current no longer flows through the body diode.

[0090] For battery packs that meet the discharge permit conditions but have a low state of charge (SOC) and whose SOC difference with the first battery pack exceeds the maximum SOC threshold, resulting in all charge / discharge switches being disconnected, the main control board will turn on its discharge switch once the SOC difference with the first battery pack is reduced to within the threshold range, allowing it to connect to the discharge circuit while keeping the charging switch disconnected. Subsequently, when the bus voltage drops to a level that can form an effective discharge current, the battery pack's built-in BMS will automatically turn on the charging switch to complete parallel operation, allowing it to charge and discharge synchronously with other battery packs already connected to the bus.

[0091] Among them, the discharge permission condition is that the battery pack voltage, temperature, protection status and other parameters meet the safe discharge standard before the discharge MOSFET can be turned on to output electrical energy.

[0092] By selecting priority discharge battery packs through a dual verification mechanism combining voltage and state of charge, and then controlling the charging and discharging switching sequence of each battery pack in stages, each battery pack is put into the discharge circuit in batches according to the state of charge difference threshold. The buffer transition is achieved by relying on the voltage difference of the bus body diode and the local BMS of the battery pack to complete the parallel operation autonomously. This can effectively suppress the impact circulating current generated by the instantaneous discharge of multiple battery packs in parallel, avoid the problem of the continuous widening of the state of charge difference between battery packs and the inability of low-charge batteries to participate in discharge for a long time due to the selection of packs based solely on terminal voltage, reduce the heat loss caused by the long-term flow of branch current through the body diode, improve the discharge efficiency and operational stability of the energy storage equipment, achieve balanced discharge of all battery packs, and extend the service life of the entire energy storage equipment cells.

[0093] The technical solution of this invention involves acquiring a fifth battery pack and a sixth battery pack; determining whether the state of charge (SOC) of the fifth battery pack is less than that of the sixth battery pack, and whether the difference between the SOCs of the fifth and sixth battery packs is greater than a preset maximum SOC threshold; if so, the sixth battery pack is designated as the first battery pack; otherwise, the fifth battery pack is designated as the first battery pack. Then, a second battery pack is determined; a parallel operation strategy is implemented for the first and second battery packs to achieve dynamic parallel operation. By implementing this technical solution, a dual verification mechanism of voltage and SOC is used to correct the discharge priority, avoiding the polarization voltage misjudgment problem caused by relying solely on battery terminal voltage to select the discharge battery pack. This effectively prevents the continuous widening of the SOC difference between battery packs and the long-term inability of high-capacity batteries to connect to the discharge circuit, thus improving the balanced discharge capability and overall operational stability of the energy storage device.

[0094] Example 4 Figure 6 This is a schematic diagram of a dynamic parallel operation process for a battery pack according to Embodiment 4 of the present invention. The relationship between this embodiment and the above embodiments is a detailed description of the execution process of the battery pack parallel operation strategy. Figure 6 As shown, the method includes: S610. Determine the first battery pack based on the voltage and state of charge of each battery pack in the energy storage device.

[0095] S620. Determine the second battery pack; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold.

[0096] S630. If no power input is detected, the second strategy is executed for the first battery pack and the second battery pack.

[0097] In this scheme, the core objective of the parallel operation strategy is to connect a new battery pack during the charging and discharging operation of the energy storage device, so that the new battery pack can be smoothly connected to the charging and discharging circuit without generating impact circulating current and avoiding damage to the devices and cells.

[0098] Specifically, Figure 7 The parallel control flowchart provided in Embodiment 4 of this application is as follows: Figure 7 As shown, the main control board detects whether a new battery pack has been connected. If a new battery pack is detected, it first completes the addressing operation for the new battery pack. During the addressing process, the existing parallel operation status remains unchanged, and no switch on / off switching is performed. Only after the addressing is completed can the next process be entered. If no new battery pack is detected, the subsequent steps are executed directly.

[0099] Furthermore, such as Figure 7 As shown, the main control board determines whether the total number of currently connected battery packs has changed; if the number of battery packs has not changed, it proceeds directly to the next step; if the number of battery packs has changed, it initiates either the first strategy or the second strategy.

[0100] Specifically, such as Figure 7 As shown, the main control board detects whether there is a power input to the energy storage device. If there is no power input, the second strategy is executed for the first and second battery packs. Here, power input refers to the external charging power supply providing electrical energy to the energy storage device.

[0101] S640. If a power input is detected, then based on the current state of the energy storage device, execute a first strategy or a second strategy on the first battery pack and the second battery pack; wherein, the current state is the real-time operating power state of the energy storage device.

[0102] In this scheme, the current state is the real-time operating power state of the energy storage device, which is divided into five categories: standby state, charging state, discharging state, power flow charging state, and power flow discharging state.

[0103] Among them, the standby state is the operating state when the whole machine has completed power-on initialization or when no battery pack is connected; the charging state is when the energy storage device's discharge circuit is off, an external charging source is connected, and the battery pack is in charging condition; the discharging state is when the energy storage device has no external charging source connected and only outputs electrical energy; the power flow charging state is when the energy storage device is connected to a charging source and the discharge circuit is conducting, the battery pack is charging and discharging simultaneously, and the charging power is greater than the discharging power; the power flow discharging state is when the energy storage device is connected to a charging source and the discharge circuit is conducting, the battery pack is charging and discharging simultaneously, and the charging power is less than the discharging power.

[0104] Furthermore, when the energy storage device is in a charging state, discharging state, power flow charging state, or power flow discharging state and meets the corresponding judgment conditions, the main control board will trigger the battery pack to execute the first strategy or the second strategy to complete the device parallel operation status update.

[0105] Specifically, the main control board collects external charging input voltage, charging and discharging current of each battery pack, charging and discharging switch on / off signals, and state of charge and voltage data uploaded by each battery pack BMS in real time, and comprehensively determines the current status of the energy storage device by combining the number of online battery packs.

[0106] In this embodiment, if the main control board detects a power input, it obtains the current state of the energy storage device and, based on the current state, executes either a first strategy or a second strategy on the first and second battery packs. For example, if the current state is charging, the first strategy is executed on the first and second battery packs; if the current state is discharging, the second strategy is executed on the first and second battery packs.

[0107] Optionally, based on the current state of the energy storage device, a first strategy or a second strategy may be implemented for the first battery pack and the second battery pack, including: If the current state is a charging state, then the first strategy is executed for the first battery pack and the second battery pack; If the current state is a discharge state, then the second strategy is executed for the first battery pack and the second battery pack; If the current state is a power flow discharge state, then the second strategy is executed on the first battery pack and the second battery pack; wherein the discharge power corresponding to the power flow discharge state is greater than the charging power; If the current state is a power flow charging state, it is determined whether the third battery pack has the conditions for discharging; if yes, the first strategy is executed for the first battery pack and the second battery pack; if no, the second strategy is executed for the first battery pack and the second battery pack; wherein, the charging power corresponding to the power flow charging state is greater than the discharging power; the third battery pack is the battery pack with the lowest voltage in the energy storage device.

[0108] In this plan, such as Figure 7 As shown, if the current state is charging, the first strategy is executed for the first and second battery packs; after the first strategy is executed, the system continues to detect whether a new battery pack has been added to the energy storage device.

[0109] In this embodiment, as Figure 7 As shown, if the current state is a discharge state, the second strategy is executed on the first and second battery packs; after the second strategy is executed, the system continues to detect whether there is a new battery pack connected to the energy storage device.

[0110] Among them, such as Figure 7 As shown, if the current state is a power flow discharge state, the second strategy is executed on the first battery pack and the second battery pack; after the second strategy is executed, the system continues to detect whether there is a new battery pack connected to the energy storage device.

[0111] Furthermore, such as Figure 7 As shown, if the current state is a power flow charging state, it means that the charging and discharging circuits of the energy storage device are simultaneously conducting, and the total charging power is greater than the total discharging power. At this time, the third battery pack with the lowest voltage is used as the criterion: if this battery pack meets the discharge permitting conditions, the first strategy is executed for the first and second battery packs, allowing the newly added battery pack to participate in charging; if this battery pack does not meet the discharge permitting conditions, the second strategy is executed for the first and second battery packs. After all strategies are executed, the system continues to detect whether any new battery packs have been connected to the energy storage device.

[0112] In this scheme, for the current charging state, the third battery pack with the lowest voltage is selected as the logical judgment benchmark. If the low-voltage third battery pack does not meet the discharge permission conditions but still executes the first strategy, it will cause a power outage fault in the energy storage device: After executing the first strategy, the energy storage device prioritizes charging the low-voltage battery pack, and the other original battery packs either close the charging switch and open the discharging switch to wait for charging, or both the charging and discharging switches are turned off, and there are no usable discharging battery packs in the energy storage device; the main control board will directly cut off the discharge output for safety protection logic, and the power supply to the load will be forced to stop.

[0113] For example: The original main control battery pack and the No. 1 expansion battery pack in the energy storage device both have a state of charge (SOC) higher than 90%, and the device maintains a power flow charging state where the charging power is greater than the discharging power. At this time, the No. 2 expansion battery pack is hot-swapped in. This battery pack is severely undervoltage, with an SOC close to 0, and does not meet the discharge permit conditions. If the first strategy is directly activated, the SOC difference between the two original high-charge battery packs and the undervoltage No. 2 battery pack exceeds the preset maximum SOC threshold, causing both original battery packs' charge / discharge switches to disconnect. Furthermore, since the No. 2 battery pack itself is undervoltage and cannot discharge, and there is uncertainty regarding random load surges, the main control board will forcibly shut down the discharge circuit to avoid deep over-discharge and permanent damage to the undervoltage cells caused by a sudden high-power load. In actual use, this will result in a significant defect: the device, which was originally operating stably under load while charging, will, although it can charge the new undervoltage battery pack after connection, directly disconnect the load, violating the product design principle of prioritizing discharge in energy storage devices.

[0114] Conversely, when the low-voltage battery pack does not support discharge, the second strategy is executed, which can solve the above problem with the BMS's built-in power replenishment mechanism: the power replenishment device will restore the undervoltage battery pack with a state of charge of 0 to a state of charge of 1; after the energy storage device maintains a charging power greater than the discharging power, the first strategy is executed again. At this time, the low-voltage battery pack has stored a basic amount of energy, and the main control board has sufficient adjustment buffer space to cope with instantaneous load fluctuations, eliminating the risk of damage to undervoltage cells due to over-discharge from the bottom layer. After the entire switching logic is completed, the energy storage device returns to the initial cycle detection step.

[0115] Based on the different operating conditions of energy storage devices, a parallel operation strategy is selected. Under the power flow charging state, the discharge capacity of the battery pack with the lowest voltage is used as the subdivision judgment criterion, taking into account both the continuous power supply requirements of the load and the safety protection of the battery cells, so as to realize the dynamic parallel operation of multiple battery packs.

[0116] Optionally, after implementing the parallel operation strategy for the first battery pack and the second battery pack, the method further includes: Obtain the operating status information of the energy storage device; Based on the current state and the operating condition information, the current state is switched.

[0117] Among them, the operating condition information is the real-time operating status of the energy storage device determined by the main control board after collecting charging input, charging and discharging power, switch status, state of charge of each battery pack and voltage.

[0118] In this solution, the main control board combines the operating condition information and current operating status of the energy storage device to complete the switching logic control of the energy storage device's operating conditions.

[0119] Specifically, the current state is standby: if a power input is detected and there is a normally rechargeable battery pack in the energy storage device, the main control board executes the first strategy to switch the current state to charging state; if the above conditions are not met, the second strategy is executed to switch the current state to discharging state, and then returns to the initial loop detection step.

[0120] In this embodiment, Figure 8 This is a flowchart of the discharge processing provided in Embodiment 4 of this application, as follows: Figure 8 As shown, the current state is the discharge state, and the control logic is as follows: If the priority discharge battery pack experiences a discharge failure, the main control board will re-run the second strategy, reselect the priority discharge battery pack, and return to the initial loop detection step after processing is complete.

[0121] For the remaining battery packs without discharge faults, if the difference in state of charge between them and the priority discharge battery pack previously exceeded the maximum state of charge threshold and the charge / discharge switch remained off, when the current difference falls back to within the threshold, the main control board turns on its discharge switch, allowing the battery pack to participate in the discharge and continue to execute subsequent judgments. If all discharge circuits of the device are turned off, an external charging power supply is connected, and a rechargeable battery pack is available, the main control board executes the first strategy, switches the current state to the charging state, and returns to the initial loop detection step after processing is completed. If the device's discharge circuit is on, an external charging power supply is connected and the charging power is greater than the discharge power, and the battery pack with the lowest overall voltage meets the discharge permit conditions, the main control board executes the first strategy, switches the current state to power flow charging state, and returns to the initial loop detection step after processing.

[0122] Furthermore, Figure 9 This is a flowchart of the charging process provided in Embodiment 4 of this application, as follows: Figure 9 As shown, the current state is charging, and the control logic is as follows: If the priority charging battery pack fails to charge, the main control board will re-run the first strategy, reselect the priority charging battery pack, and return to the initial loop detection step after processing is completed. For the remaining battery packs without charging faults, if the difference in state of charge between them and the priority charging battery pack previously exceeded the maximum state of charge threshold and the charge / discharge switch remained off, when the current difference falls back to within the threshold, the main control board turns on its charging switch, allowing the battery pack to participate in charging, and continues to execute subsequent judgments. If the external charging power is disconnected, or if no battery pack in the device meets the charging permission conditions, the main control board executes the second strategy, switches the current state to the discharge state, and returns to the initial loop detection step after the processing is completed. If the device discharge circuit is open and the discharge power is greater than the charging power, the main control board executes the second strategy, switches the current state to power flow discharge state, and returns to the initial loop detection step after processing.

[0123] In this embodiment, Figure 10 This is a flowchart of the power flow discharge processing provided in Embodiment 4 of this application, as follows: Figure 10 As shown, the current state is power flow discharge state, and the control logic is as follows: If the priority discharge battery pack fails to discharge, the main control board will re-run the second strategy, reselect the priority discharge battery pack, and return to the initial loop detection step after processing is completed. For the remaining battery packs without discharge faults, if the difference in state of charge between them and the priority discharge battery pack previously exceeded the maximum state of charge threshold and the charge / discharge switch remained off, when the current difference falls back to within the threshold, the main control board turns on its discharge switch, allowing the battery pack to participate in the discharge and continue to execute subsequent judgments. If the external charging power is disconnected, or if no battery pack in the device meets the charging permission conditions, the current state will be directly switched to the discharge state without the need to execute the second strategy. After the process is completed, the device will return to the initial loop detection step. If all discharge circuits of the device are turned off, an external charging power supply is connected, and a rechargeable battery pack is available, the main control board executes the first strategy, switches the current state to the charging state, and returns to the initial loop detection step after processing is completed. If the device's discharge circuit is on, an external charging power supply is connected and the charging power is greater than the discharge power, and the battery pack with the lowest overall voltage meets the discharge permit conditions, the main control board executes the first strategy, switches the current state to power flow charging state, and returns to the initial loop detection step after processing.

[0124] Furthermore, Figure 11 The power flow charging flowchart provided in Embodiment 4 of this application is as follows: Figure 11 As shown, the current state is the current charging state, and the control logic is as follows: If the priority charging battery pack fails to charge, the main control board will re-run the first strategy, reselect the priority charging battery pack, and return to the initial loop detection step after processing is completed. For the remaining battery packs without charging faults, if the difference in state of charge between them and the priority charging battery pack previously exceeded the maximum state of charge threshold and the charge / discharge switch remained off, when the current difference falls back to within the threshold, the main control board turns on its charging switch, allowing the battery pack to participate in charging, and continues to execute subsequent judgments. If all discharge circuits of the device are turned off, the current state is directly switched to the charging state without the need to execute the first strategy. After the process is completed, the device returns to the initial loop detection step. If the external charging power is disconnected, or if no battery pack in the device meets the charging permission conditions, the main control board executes the second strategy, switches the current state to the discharge state, and returns to the initial loop detection step after the processing is completed. If the device discharge circuit is open and the discharge power is greater than the charging power, the main control board executes the second strategy, switches the current state to power flow discharge state, and returns to the initial loop detection step after processing.

[0125] Based on the above-mentioned multi-condition hierarchical control logic, dynamic parallel operation is realized, supporting hot-swappable battery packs for plug-and-play use; the energy storage device can fully charge and completely discharge all battery packs, and there is no impact circulating current damaging the cells and circuits during the parallel connection process, while avoiding power interruption to the load, taking into account both equipment operation safety and user experience.

[0126] The technical solution of this invention determines a first battery pack based on the voltage and state of charge of each battery pack in the energy storage device; then determines a second battery pack; if no power input is detected, a second strategy is executed for the first and second battery packs; if power input is detected, a first strategy or a second strategy is executed for the first and second battery packs based on the current state of the energy storage device. By implementing this technical solution, through parallel operation strategy and maximum state of charge difference control, circulating current impacts caused by mutual charging of battery packs with large voltage differences are prevented, effectively protecting the circuit and various power components, and extending the service life of the entire device; at the same time, relying on dynamic parallel operation capability, the expansion battery pack can be hot-swapped and used immediately, without the user having to shut down the charging and discharging load in advance to add an expansion battery pack, adapting to use scenarios such as emergency continuous power supply where discharge cannot be interrupted, greatly improving the product's flexibility, user experience, and level of intelligence.

[0127] Example 5 Figure 12 This is a schematic diagram of another dynamic parallel operation process of a battery pack provided in Embodiment 5 of the present invention. The relationship between this embodiment and the above embodiments is a detailed description of the battery pack charging process. Figure 12 As shown, the method includes: S1210. Each of the battery packs is recharged using a recharging device; wherein the recharging device is integrated into the battery management system corresponding to each of the battery packs.

[0128] In this scheme, in order to optimize the dynamic parallel switching performance of energy storage equipment and ensure the continuous and stable operation of the original discharge circuit, a power replenishment device is added to the BMS.

[0129] Specifically, the working logic of the charging device is as follows: When the state of charge of the battery pack drops to 0, the BMS can draw a small current from the DC bus to precharge the cells through an independent charging device until the state of charge rises to 1% or a higher preset threshold. The charging circuit path is independent of the main power circuit. The small charging current does not pass through the main bus line and the charge / discharge switch. The charging time can be flexibly configured according to the overall design requirements.

[0130] The technical solution of this invention uses a power replenishment device to replenish the power of each battery pack. By implementing this technical solution, permanent cell damage caused by continuous deep undervoltage of the discharged battery pack can be avoided when the energy storage device has not been connected to an external charging power source for a long time. When the energy storage device switches from power flow discharge state to power flow charging state, it can solve the pain points of the lowest voltage battery pack having no discharge capacity and the switching strategy triggering load discharge interruption, thus ensuring the priority of discharge for the energy storage device.

[0131] Example 6 Figure 13This is a schematic diagram of another dynamic parallel operation process of a battery pack provided in Embodiment Six of the present invention. The relationship between this embodiment and the above embodiments is a detailed description of the battery pack connection process. The charging switch and discharging switch of the battery pack have independent on / off functions; the battery pack is connected via a parallel operation cable; the parallel operation cable includes a host presence signal line; as shown... Figure 13 As shown, the method includes: S1310. The connection status of the battery pack is identified by the signal transmitted through the host in-situ signal line.

[0132] In this solution, the charging switch and discharging switch of the battery pack on the BMS motherboard have independent on / off functions.

[0133] Specifically, a dedicated driver chip is used that can independently control the charging and discharging switches of the battery pack, completely eliminating the inherent constraint of forced linkage of charging and discharging switches in traditional solutions. This avoids operational defects such as short-term power supply vacuum on the bus and sharp drop in DC bus voltage during state switching from the hardware level. At the same time, it avoids the generation of huge surge currents in various capacitive loads on the bus side at the moment of power-on, effectively preventing the whole machine from being falsely triggered by overcurrent protection shutdown. It also eliminates the safety hazards of long-term impact of large surge currents causing damage to power switches, bus sampling devices, and load modules, ensuring continuous and stable power supply to the bus during dynamic switching of charging and discharging conditions and hot-swapping and parallel operation of multiple battery packs, thereby improving the overall operational stability and the service life of the components.

[0134] In this plan, Figure 14 This is a structural diagram of the energy storage device provided in Embodiment Six of this application, as shown below. Figure 14 As shown, the expanded capacity battery pack is connected to the main control battery pack via a parallel cable.

[0135] Specifically, the parallel cable integrates the host presence signal line, which is a 5V hardware level signal output by the main control board, maintaining a high level under normal operating conditions. All expansion battery packs connected to the bus can acquire this level signal in real time. Once the level drops to a low level, it can be determined that the corresponding expansion battery pack has disconnected from the main control battery pack. Relying on hardware level for presence identification results in fast signal response, high reliability, and is unaffected by the software program's operating status.

[0136] Furthermore, hardware level signals are transmitted via the host in-situ signal line to identify the physical connection status between each expanded capacity battery pack and the main control battery pack in real time.

[0137] S1320. When the connection state is not connected, the charging switch and discharging switch of the battery pack are disconnected.

[0138] Furthermore, if the battery pack connection status is detected as not connected, it is determined that the battery pack circuit is disconnected, and a control command is immediately output to turn off its charging switch and discharging switch.

[0139] Specifically, the BMS software accompanying the expanded battery pack can complete connectivity detection and logic determination within 100ms, then quickly shut off the charging / discharging switch, clear the device communication address, and exit the parallel operation state. This rapid hardware detection and protection logic is the core key to achieving safe dynamic parallel operation. After the expanded battery pack is disconnected from the main control battery pack link, the power circuit must be cut off extremely quickly. The faster the response speed, the better the protection effect, effectively preventing users from quickly reinserting the removed battery pack into the host, which could cause excessive circulating current and burn out circuits and power devices.

[0140] For example: The main control battery pack has only 1% charge remaining, while the expansion battery pack is fully charged. Under normal conditions, the fully charged expansion battery pack prioritizes discharging the load, and its charge / discharge switch remains on. In the low-charge state, the main control battery pack's charge / discharge switch is off. If the expansion battery pack is removed at this time, the main control battery pack will turn on its own power switch to maintain power supply to the load. If the removed expansion battery pack fails to turn off its switch in time and is immediately reinserted into the main control battery pack, the high and low voltage differential battery packs will be directly connected in parallel, instantly generating a high-amplitude inrush circulating current, which can easily cause irreversible damage to cables and MOSFETs.

[0141] This solution achieves millisecond-level presence status identification through an independent hardware host presence signal line, without occupying the device's communication bandwidth, and the status determination is stable and highly reliable.

[0142] Furthermore, the parallel cable also integrates two types of hardware signal lines: the expansion battery pack access signal line and the expansion battery pack addressing enable signal line. The expansion battery pack access signal line is used for hardware identification to determine whether the expansion battery pack has completed its physical connection with the main control battery pack; the expansion battery pack addressing enable signal line is used to send addressing trigger signals to achieve independent address allocation for each expansion battery pack.

[0143] In this embodiment, the parallel cable also integrates power lines and communication lines. The power lines carry the large current of charging and discharging, while the communication lines realize the command control and status interaction between the main control battery pack and the expansion battery pack.

[0144] In this embodiment, Figure 15 This is a schematic diagram of the parallel cable interface provided in Embodiment Six of this application, as shown below. Figure 15As shown, the areas marked with "+" and "-" on the interface are the positive and negative terminals of the main circuit bus that carries current transmission. The functional definitions of pins 1 to 8 on the interface are as follows: pin 1 is ground (GND), pin 2 is the host presence signal, pin 3 is the expansion battery pack access signal, pin 4 is the expansion battery pack addressing enable signal, pins 5 and 8 are reserved for backup, pin 6 is the CAN communication high line (CAN-H), and pin 7 is the CAN communication low line (CAN-L).

[0145] The technical solution of this invention identifies the connectivity status of the battery pack through signals transmitted via the host presence signal line. When the connectivity status is not connected, the charging and discharging switches of the battery pack are disconnected. By implementing this technical solution, the risk of bus power supply vacuum and high-current surges during state switching is eliminated by independently controllable charging and discharging switches. Combined with a dedicated parallel cable integrating the host presence signal line, hardware-level rapid online identification is achieved. The charging and discharging circuit can be immediately cut off when the battery pack goes offline, effectively avoiding the large circulating current generated by the parallel connection of high and low voltage differences when plugging and unplugging the battery pack, protecting power devices and circuit safety. It eliminates the need to rely on high-frequency communication messages to determine the offline status, reducing the bus communication load and improving the response speed, operational stability, and overall safety of dynamic parallel operation of multiple battery packs during hot-swapping.

[0146] Example 7 Figure 16 This is a schematic diagram of a battery pack dynamic parallel operation device provided in Embodiment 7 of the present invention. Figure 16 As shown, the device includes: The first battery pack determination module 1610 is used to determine the first battery pack based on the voltage and state of charge of each battery pack in the energy storage device. The second battery pack determination module 1620 is used to determine the second battery pack; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold. The dynamic parallel operation module 1630 is used to execute a parallel operation strategy on the first battery pack and the second battery pack to realize dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the battery pack charging switch and discharging switch.

[0147] Optionally, the first battery pack determination module 1610 is specifically used for: Obtain a third battery pack and a fourth battery pack; wherein the third battery pack is the battery pack with the lowest voltage in the energy storage device; and the fourth battery pack is the battery pack with the lowest state of charge in the energy storage device. Determine whether the state of charge of the third battery pack is greater than the state of charge of the fourth battery pack, and whether the difference between the state of charge of the third battery pack and the state of charge of the fourth battery pack is greater than a preset maximum state of charge threshold. If so, then the fourth battery pack is identified as the first battery pack; If not, then the third battery pack is identified as the first battery pack.

[0148] Optionally, the parallel operation strategy includes a first strategy; the dynamic parallel operation module 1630 is specifically used for: Control the charging switch of the first battery pack to open and the discharging switch to close; Controls the closing of the charging switch and the opening of the discharging switch of the second battery pack; Control the charging switch of the first battery pack to close; When the charging current of the second battery pack is detected, the discharge switch of the second battery pack is controlled to close.

[0149] Optionally, the first battery pack determination module 1610 is also used for: Obtain a fifth battery pack and a sixth battery pack; wherein the fifth battery pack is the battery pack with the highest voltage in the energy storage device; and the sixth battery pack is the battery pack with the largest state of charge in the energy storage device. Determine whether the state of charge of the fifth battery pack is less than the state of charge of the sixth battery pack, and whether the difference between the state of charge of the fifth battery pack and the state of charge of the sixth battery pack is greater than a preset maximum state of charge threshold. If so, then the sixth battery pack is identified as the first battery pack; If not, then the fifth battery pack is identified as the first battery pack.

[0150] Optionally, the parallel operation strategy includes a second strategy, and the dynamic parallel operation module 1630 is further used for: Controls the charging switch of the second battery pack to open and the discharging switch to close; Control the closing of the charging switch and the discharging switch of the first battery pack; When the discharge current of the second battery pack is detected, the charging switch of the second battery pack is closed.

[0151] Optional, the dynamic parallel module 1630 includes: The second strategy execution submodule is used to execute the second strategy on the first battery pack and the second battery pack if no power input is detected. The strategy execution submodule is used to execute a first strategy or a second strategy on the first battery pack and the second battery pack according to the current state of the energy storage device if a power input is detected; wherein the current state is the real-time operating power state of the energy storage device.

[0152] Optional, the policy execution submodule, specifically used for: If the current state is a charging state, then the first strategy is executed for the first battery pack and the second battery pack; If the current state is a discharge state, then the second strategy is executed for the first battery pack and the second battery pack; If the current state is a power flow discharge state, then the second strategy is executed on the first battery pack and the second battery pack; wherein the discharge power corresponding to the power flow discharge state is greater than the charging power; If the current state is a power flow charging state, it is determined whether the third battery pack has the conditions for discharging; if yes, the first strategy is executed for the first battery pack and the second battery pack; if no, the second strategy is executed for the first battery pack and the second battery pack; wherein, the charging power corresponding to the power flow charging state is greater than the discharging power; the third battery pack is the battery pack with the lowest voltage in the energy storage device.

[0153] Optionally, the device further includes: Operating condition information acquisition module, used to acquire operating condition information of the energy storage device; The current state switching module is used to control the switching of the current state based on the current state and the operating condition information.

[0154] Optionally, the device further includes: A charging module is used to charge each of the battery packs via a charging device; wherein the charging device is integrated into the battery management system corresponding to each of the battery packs.

[0155] Optionally, the charging switch and discharging switch of the battery pack have independent on / off functions; the battery pack is connected via a parallel cable; the parallel cable includes a host presence signal line; the device further includes: A connectivity identification module is used to identify the connectivity status of the battery pack through signals transmitted by the host in-situ signal line; The switch control module is used to control the charging switch and discharging switch of the battery pack to disconnect when the connection state is not connected.

[0156] The battery pack dynamic parallel operation device provided in this embodiment of the invention can execute the battery pack dynamic parallel operation method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0157] Example 8 Figure 17 A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0158] like Figure 17 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0159] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0160] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as a dynamic parallel operation method for a battery pack.

[0161] In some embodiments, a battery pack dynamic parallel operation method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the battery pack dynamic parallel operation method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform a battery pack dynamic parallel operation method by any other suitable means (e.g., by means of firmware).

[0162] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transferring data and instructions to the storage system, the at least one input device, and the at least one output device.

[0163] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0164] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0165] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0166] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0167] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0168] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include an energy storage device comprising an energy storage device program carried on a non-transitory computer-readable medium, the energy storage device program containing program code for performing the methods shown in the flowcharts. In such embodiments, the energy storage device program can be downloaded and installed from a network via communication unit 19, or installed from storage unit 18, or installed from ROM 12. When the energy storage device program is executed by processor 11, it performs the functions defined in the methods of the embodiments of the present invention.

[0169] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0170] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for dynamic parallel operation of a battery pack, characterized in that, include: The first battery pack is determined based on the voltage and state of charge of each battery pack in the energy storage device; A second battery pack is identified; wherein the second battery pack is the remaining battery packs in the energy storage device other than the first battery pack; the difference between the state of charge of the second battery pack and the state of charge of the first battery pack is less than a preset maximum state of charge threshold. A parallel operation strategy is implemented for the first battery pack and the second battery pack to achieve dynamic parallel operation of the first battery pack and the second battery pack; wherein, the parallel operation strategy is to control the on / off state of the charging switch and the discharging switch of the battery pack.

2. The method according to claim 1, characterized in that, Based on the voltage and state of charge of each battery pack in the energy storage device, the first battery pack is determined, including: Obtain a third battery pack and a fourth battery pack; wherein the third battery pack is the battery pack with the lowest voltage in the energy storage device; and the fourth battery pack is the battery pack with the lowest state of charge in the energy storage device. Determine whether the state of charge of the third battery pack is greater than the state of charge of the fourth battery pack, and whether the difference between the state of charge of the third battery pack and the state of charge of the fourth battery pack is greater than a preset maximum state of charge threshold. If so, then the fourth battery pack is identified as the first battery pack; If not, then the third battery pack is identified as the first battery pack.

3. The method according to claim 2, characterized in that, The parallel operation strategy includes a first strategy; executing the first strategy on the first battery pack and the second battery pack includes: Control the charging switch of the first battery pack to open and the discharging switch to close; Controls the closing of the charging switch and the opening of the discharging switch of the second battery pack; Control the charging switch of the first battery pack to close; When the charging current of the second battery pack is detected, the discharge switch of the second battery pack is controlled to close.

4. The method according to claim 1, characterized in that, Based on the voltage and state of charge of each battery pack in the energy storage device, the first battery pack is determined, including: Obtain a fifth battery pack and a sixth battery pack; wherein the fifth battery pack is the battery pack with the highest voltage in the energy storage device; and the sixth battery pack is the battery pack with the largest state of charge in the energy storage device. Determine whether the state of charge of the fifth battery pack is less than the state of charge of the sixth battery pack, and whether the difference between the state of charge of the fifth battery pack and the state of charge of the sixth battery pack is greater than a preset maximum state of charge threshold. If so, then the sixth battery pack is identified as the first battery pack; If not, then the fifth battery pack is identified as the first battery pack.

5. The method according to claim 4, characterized in that, The parallel operation strategy includes a second strategy, which is executed on both the first battery pack and the second battery pack, including: Controls the charging switch of the second battery pack to open and the discharging switch to close; Control the closing of the charging switch and the discharging switch of the first battery pack; When the discharge current of the second battery pack is detected, the charging switch of the second battery pack is closed.

6. The method according to claim 1, characterized in that, Executing a parallel operation strategy for the first battery pack and the second battery pack includes: If no power input is detected, the second strategy is executed for both the first and second battery packs; If a power input is detected, a first strategy or a second strategy is executed on the first battery pack and the second battery pack according to the current state of the energy storage device; wherein the current state is the real-time operating power state of the energy storage device.

7. The method according to claim 6, characterized in that, Based on the current state of the energy storage device, a first strategy or a second strategy is executed on the first battery pack and the second battery pack, including: If the current state is a charging state, then the first strategy is executed for the first battery pack and the second battery pack; If the current state is a discharge state, then the second strategy is executed for the first battery pack and the second battery pack; If the current state is a power flow discharge state, then the second strategy is executed on the first battery pack and the second battery pack; wherein the discharge power corresponding to the power flow discharge state is greater than the charging power; If the current state is a power flow charging state, it is determined whether the third battery pack has the conditions for discharging; if yes, the first strategy is executed for the first battery pack and the second battery pack; if no, the second strategy is executed for the first battery pack and the second battery pack; wherein, the charging power corresponding to the power flow charging state is greater than the discharging power; the third battery pack is the battery pack with the lowest voltage in the energy storage device.

8. The method according to claim 7, characterized in that, After implementing the parallel operation strategy for the first battery pack and the second battery pack, the method further includes: Obtain the operating status information of the energy storage device; Based on the current state and the operating condition information, the current state is switched.

9. The method according to any one of claims 1-8, characterized in that, The method further includes: Each of the battery packs is recharged using a recharging device; wherein the recharging device is integrated into the battery management system corresponding to each of the battery packs.

10. The method according to any one of claims 1-8, characterized in that, The charging switch and discharging switch of the battery pack have independent on / off functions; The battery pack is connected via a parallel cable; the parallel cable includes a host presence signal line; the method further includes: The connectivity status of the battery pack is identified by the signal transmitted through the host in-situ signal line; When the connection state is not connected, the charging switch and discharging switch of the battery pack are disconnected.

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