Battery pack parallel operation method, battery management system, energy storage system and storage medium

Abstract

The invention provides a battery pack parallel operation method, a battery management system, an energy storage system and a storage medium. The battery pack parallel operation method comprises the steps that bus voltage is acquired, and whether the bus voltage is within a preset voltage range or not is judged; when the bus voltage is within a preset voltage range, acquiring a current battery pack voltage, and judging whether the current battery pack voltage is greater than the bus voltage, and if so, entering a high-voltage to low-voltage parallel operation mode; otherwise, entering a low-voltage-to-high-voltage parallel operation mode. The problem of current circulation can be solved, and system parallel operation can be completed under any working condition.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage batteries, and in particular to a battery pack parallel connection method, a battery management system, an energy storage system and a storage medium. Background Art

[0002] In energy storage systems, it is common to connect multiple battery systems in parallel to meet charging and discharging requirements. When multiple battery systems are used in parallel, there are situations where battery systems with inconsistent total voltages are used in parallel. Under this condition, there is a large current circulation between the battery systems. In severe cases, it will trigger an overcurrent fault in the battery system, affecting the life of components in the battery system or causing safety issues. Summary of the invention

[0003] In order to solve the above-mentioned technical problems, the present application provides a battery pack parallel connection method, a battery management system, an energy storage system and a storage medium that can solve the current circulation problem.

[0004] Specifically, the present application provides a battery pack parallel connection method, comprising the following steps: A bus voltage is obtained, and it is determined whether the bus voltage is within a preset voltage range.

[0005] When the bus voltage is within the preset voltage range, the current battery pack voltage is obtained, and it is determined whether the current battery pack voltage is greater than the bus voltage. If so, the high voltage access to low voltage parallel mode is entered; otherwise, the low voltage access to high voltage parallel mode is entered.

[0006] In the above technical solution, by judging the bus voltage and the battery pack voltage and selecting different parallel modes according to different situations, the circulation caused by voltage inconsistency between battery systems can be effectively avoided, thereby reducing the risk of overcurrent failure; by reasonable parallel management, unnecessary current circulation can be reduced, which can effectively reduce the loss of components in the battery system and extend the battery life.

[0007] In addition, judging whether the bus voltage is within the preset voltage range is to solve the problem that when all battery systems are not powered on for the first time, there is no voltage on the bus or the voltage is not determined, and it is impossible to enter the high voltage or low voltage judgment. At this time, the battery system with the highest total voltage is powered on, and the system bus has voltage.

[0008] Therefore, the above parallel connection method can solve the current circulation problem and can complete system parallel connection under any working conditions.

[0009] Furthermore, the high voltage connected to low voltage parallel mode includes: Obtain the current operating state of the battery system; wherein the operating state at least includes an idle state, a charging state, and a discharging state.

[0010] If the operating state is an idle state, the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than a first preset voltage value, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

[0011] If the operating state is the charging state, the discharge MOS corresponding to the current battery pack is disconnected, and the corresponding charging MOS is closed at the same time, and the internal and external pressure difference of the current battery pack is detected in real time. When the internal and external pressure difference is less than or equal to the second preset voltage value, the discharge MOS corresponding to the current battery pack is closed to complete the parallel operation.

[0012] If the operating state is the discharge state, the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than or equal to the second preset voltage value, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

[0013] In the above technical solution, by obtaining the specific operating status of the battery system (idle, charging, discharging), specific access methods can be adopted for different statuses, thereby improving the flexibility and adaptability of the parallel operation process and ensuring that operations are performed under appropriate conditions; directly closing the charging MOS and discharging MOS in the idle state avoids unnecessary frequent operations, thereby reducing the mechanical wear of the device and extending the service life of the MOS tube; through real-time monitoring of the internal and external pressure difference (voltage difference), combined with the set first and second preset voltage values, judgment is made to ensure that parallel operation is performed only under safe and appropriate conditions, significantly reducing the risk of overcurrent and failure.

[0014] Furthermore, the low voltage connected to high voltage parallel mode includes: The current internal and external pressure difference of the battery pack is obtained, and it is determined whether the internal and external pressure difference is greater than or equal to a first preset voltage value. If so, the first parallel mode is entered; otherwise, the second parallel mode is entered.

[0015] In the above technical solution, by obtaining the internal and external pressure difference of the current battery pack and setting the first preset voltage value as the judgment condition, this mode can ensure that the parallel operation is performed only when the internal and external pressure difference of the battery pack is within a safe range. This effectively avoids safety risks such as current circulation, battery overheating and even short circuit that may be caused by excessive pressure difference, thereby significantly improving the safety of the parallel process; according to the different internal and external pressure differences, this mode can intelligently choose to enter the first parallel mode or the second parallel mode. This design makes the parallel process more flexible and can make the best decision according to different situations, thereby ensuring that the battery system can operate efficiently and stably under various working conditions.

[0016] Furthermore, the first parallel mode includes: Get the current operating status of the battery system.

[0017] If the operating state is an idle state, the charging MOS corresponding to the current battery pack is disconnected, and the corresponding discharging MOS is closed.

[0018] If the operating state is the charging state, the discharge MOS and the charging current limiting module corresponding to the current battery pack are closed, and the internal and external pressure difference of the current battery pack is detected in real time. When the internal and external pressure difference is less than the first preset voltage value, the charging MOS corresponding to the current battery pack is closed, and the charging current limiting module is disconnected to complete the parallel operation.

[0019] If the operating state is the discharge state, the discharge MOS corresponding to the current battery pack is closed, and the corresponding charging MOS is disconnected at the same time, and the internal and external pressure difference and the battery pack current of the current battery pack are detected in real time. When the internal and external pressure difference is less than or equal to the second preset voltage value or the battery pack current is greater than or equal to the preset current value, the charging MOS corresponding to the current battery pack is closed to complete the parallel operation.

[0020] In the above technical solution, in the charging state, the discharge MOS and the charging current limiting module are closed to effectively control the charging current and ensure the safety and stability of the charging process. The charging MOS is closed only when the internal and external pressure difference is less than the first preset voltage value to ensure that the parallel connection is completed within a safe range. This strategy can effectively avoid overload and battery damage during charging; in the discharge state, dual monitoring (internal and external pressure difference and current) provides a more stringent safety mechanism for parallel connection, which not only ensures the stability of the battery system, but also improves the reliability of smoothly connecting the battery pack to the overall system.

[0021] Furthermore, the second parallel mode includes: Get the current operating status of the battery system.

[0022] If the operating state is an idle state or a charging state, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

[0023] If the operating state is the discharge state, the discharge MOS corresponding to the current battery pack is closed, and the internal and external pressure difference and the battery pack current of the current battery pack are detected in real time. When the internal and external pressure difference is less than the second preset voltage value or the battery pack current is greater than the preset current value, the charging MOS corresponding to the current battery pack is closed to complete the parallel operation.

[0024] In the above technical solution, for different operating states, the mode can automatically adjust to the corresponding parallel operation strategy to give full play to the battery performance. For example, in the charging state, the system can be quickly connected in parallel to further improve the battery charging efficiency. In the discharging state, the discharge MOS is closed and the internal and external pressure difference and the battery pack current are monitored in real time to ensure that the parallel operation is carried out within a safe range. Through the set conditions (monitoring of pressure difference and current), safety hazards caused by abnormal conditions are effectively avoided, thereby enhancing the safety of operation.

[0025] Further, when the bus voltage is not within a preset voltage range, the method includes: Obtain the charging MOS and discharging MOS corresponding to the battery pack with the highest bus voltage and close them.

[0026] In the above technical solution, by selecting the battery pack with the highest bus voltage for rapid parallel connection, the bus voltage can be effectively increased and returned to the preset voltage range, and the power supply status of the system can be adjusted in time to ensure the stability of the power supply.

[0027] Based on the same concept, the present application also provides a battery management system, which loads and executes the battery pack paralleling method; the battery management system at least includes: The judging module is used to obtain the bus voltage and judge whether the bus voltage is within a preset voltage range, so as to enter the first parallel module when the bus voltage is within the preset range.

[0028] The first parallel module is used to obtain the current battery pack voltage and determine whether the current battery pack voltage is greater than the bus voltage. If so, it enters a high-voltage access to low-voltage parallel mode; otherwise, it enters a low-voltage access to high-voltage parallel mode.

[0029] In the above technical solution, intelligent management of voltage is realized to ensure that the system responds quickly to voltage fluctuations, maintains voltage stability, and improves system reliability and stability; the first parallel module flexibly selects the parallel mode of high voltage access to low voltage or low voltage access to high voltage based on the comparison between the current battery pack voltage and the bus voltage. This strategy can dynamically adjust the parallel mode according to actual conditions to ensure that the system can operate efficiently under different voltage conditions; by intelligently selecting the parallel mode, the system can maximize the use of battery pack voltage differences, optimize energy transmission paths, reduce energy losses, and improve overall system efficiency.

[0030] Furthermore, the judgment module is also used to enter the second parallel module when the bus voltage is not within a preset range; the second parallel module is used to obtain the charging MOS and discharging MOS corresponding to the battery pack with the highest bus voltage and close them.

[0031] In the above technical solution, when the bus voltage exceeds the preset range, the system can quickly switch to the second parallel module, immediately obtain the battery pack with the highest voltage and close its charging MOS and discharging MOS, thereby quickly increasing the bus voltage and ensuring that the system quickly returns to normal working state; this design realizes automatic voltage adjustment and can dynamically switch according to voltage conditions without human intervention, thereby improving the intelligence level and response speed of the system.

[0032] Based on the same concept, the present application also provides an energy storage system, which includes multiple battery systems connected in parallel on an energy storage bus, and the battery packs corresponding to each battery system are connected in parallel using the battery pack parallel connection method.

[0033] Based on the same concept, the present application also provides a storage medium on which at least one computer instruction is stored, and when the at least one computer instruction is executed by a processor, the battery pack parallel connection method is implemented.

[0034] Compared with the prior art, the beneficial effects of this application are: The present application first obtains the bus voltage and determines whether the bus voltage is within the preset voltage range; when the bus voltage is within the preset voltage range, obtains the current battery pack voltage and determines whether the current battery pack voltage is greater than the bus voltage. If so, enters the high voltage access low voltage parallel mode; otherwise, enters the low voltage access high voltage parallel mode. The present application can solve the current circulation problem and complete the system parallel operation under any working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of the battery pack parallel connection method described in this application.

[0036] Figure 2 Schematic diagram of the energy storage system described in this application.

[0037] Figure 3 The electrical schematic diagram of the battery system described in this application.

[0038] Figure 4 This is a framework diagram of the battery management system described in this application. DETAILED DESCRIPTION

[0039] The following is a further detailed description of a battery pack parallel connection method, a battery management system, an energy storage system and a storage medium of the present application in conjunction with specific embodiments and drawings.

[0040] Embodiment 1: See also Figure 1 The present application provides a battery pack parallel connection method, comprising the following steps: A bus voltage is obtained, and it is determined whether the bus voltage is within a preset voltage range.

[0041] When the bus voltage is within the preset voltage range, the current battery pack voltage is obtained, and it is determined whether the current battery pack voltage is greater than the bus voltage. If so, the high voltage access to low voltage parallel mode is entered; otherwise, the low voltage access to high voltage parallel mode is entered.

[0042] In some embodiments, see Figure 2 , N battery systems are connected in parallel on the energy storage system bus; where N is greater than or equal to 1.

[0043] The electrical schematic diagram of each battery system is as follows Figure 3 As shown, the positive electrode of the battery pack is connected to the discharge MOS and the charging MOS in sequence, the negative electrode of the battery pack is connected to one end of the current detection module, and the other end of the current detection module is connected to the negative electrode of the energy storage bus; the charging MOS is also connected in parallel with a charging current limiting module, and the charging MOS is connected to the positive electrode of the energy storage bus.

[0044] In some embodiments, the external voltage of the load end of the battery system, i.e., the bus voltage V_P, is detected, and then it is determined whether the bus voltage V_P is within a preset voltage range; wherein, the preset voltage range is such as 40V≤V_P≤60V, and those skilled in the art may also set other preset voltage ranges according to actual application requirements, and is not limited thereto.

[0045] Furthermore, if the bus voltage V_P is within the preset voltage range, the voltage V_BAT at both ends of the battery pack, that is, the battery pack voltage V_BAT, is further obtained, and then it is determined whether the battery pack voltage V_BAT is greater than the bus voltage V_P. If so, the high-voltage access to low-voltage parallel mode is entered; otherwise, the low-voltage access to high-voltage parallel mode is entered.

[0046] The purpose of judging whether the bus voltage is within the preset voltage range is to solve the problem that when all battery systems are powered on for the first time, there is no voltage on the bus or the voltage is not determined, and it is impossible to enter the high voltage or low voltage judgment. At this time, the battery system with the highest total voltage is powered on, and the system bus has voltage.

[0047] Further, when the bus voltage is not within a preset voltage range, the method includes: Obtain the charging MOS and discharging MOS corresponding to the battery pack with the highest bus voltage and close them.

[0048] In other embodiments, if the bus voltage V_P is not within a preset voltage range such as 40V≤V_P≤60V, it means that there is no battery pack that has been connected in parallel in the system, and the charging MOS and discharging MOS of the battery pack with the highest total bus voltage V_P in the system are closed to complete the parallel connection.

[0049] In the above technical solution, by selecting the battery pack with the highest bus voltage for rapid parallel connection, the bus voltage can be effectively increased and returned to the preset voltage range, and the power supply status of the system can be adjusted in time to ensure the stability of the power supply.

[0050] Furthermore, the high voltage connected to low voltage parallel mode includes: Obtain the current operating state of the battery system; wherein the operating state at least includes an idle state, a charging state, and a discharging state.

[0051] If the operating state is an idle state, the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than a first preset voltage value, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

[0052] In some embodiments, the system is in an idle state and determines whether the internal and external pressure difference V_diff of the current battery pack is less than a first preset voltage value. If not, it indicates that the internal and external pressure difference of the current battery pack is large. Wait for the battery system to switch its charge and discharge state before jumping to the corresponding parallel process. If so, it indicates that the internal and external pressure difference of the current battery pack is small and meets the parallel conditions. The charging MOS and the discharging MOS are closed to complete the parallel process.

[0053] Among them, the internal and external pressure difference V_diff=|bus voltage V_P-battery pack voltage V_BAT|; the first preset voltage value is 0.8V, for example, and those skilled in the art can also set it to other values ​​according to actual application requirements, and is not limited to 0.8V.

[0054] If the operating state is the charging state, the discharge MOS corresponding to the current battery pack is disconnected, and the corresponding charging MOS is closed at the same time, and the internal and external pressure difference of the current battery pack is detected in real time. When the internal and external pressure difference is less than or equal to the second preset voltage value, the discharge MOS corresponding to the current battery pack is closed to complete the parallel operation.

[0055] In some embodiments, the system is in a charging state, the discharge MOS is disconnected, the charging MOS is closed, and the high-voltage battery pack is only allowed to charge to prevent the high-voltage battery pack from discharging into the low-voltage battery pack, causing an overcurrent fault in the low-voltage battery pack; when the internal and external pressure difference V_diff is less than or equal to the second preset voltage value, the discharge MOS is closed to complete the parallel operation.

[0056] The second preset voltage value is, for example, 0.2V, and those skilled in the art may also set it to other values ​​according to actual application requirements, and is not limited to 0.2V.

[0057] If the operating state is the discharge state, the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than or equal to the second preset voltage value, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

[0058] In some embodiments, the system is in a discharging state, and determines whether the internal and external pressure difference V_diff is less than or equal to a second preset voltage value. If not, it means that the internal and external pressure difference V_diff of the battery pack is large, and waits for the battery system to switch between charging and discharging states before jumping to the corresponding parallel process; if so, it means that the internal and external pressure difference V_diff is small and meets the parallel conditions, and the charging MOS and the discharging MOS are closed to complete the parallel operation.

[0059] In the above technical solution, by obtaining the specific operating status of the battery system (idle, charging, discharging), specific access methods can be adopted for different statuses, thereby improving the flexibility and adaptability of the parallel operation process and ensuring that operations are performed under appropriate conditions; directly closing the charging MOS and discharging MOS in the idle state avoids unnecessary frequent operations, thereby reducing the mechanical wear of the device and extending the service life of the MOS tube; through real-time monitoring of the internal and external pressure difference (voltage difference), combined with the set first and second preset voltage values, judgment is made to ensure that parallel operation is performed only under safe and appropriate conditions, significantly reducing the risk of overcurrent and failure.

[0060] Furthermore, the low voltage connected to high voltage parallel mode includes: The current internal and external pressure difference of the battery pack is obtained, and it is determined whether the internal and external pressure difference is greater than or equal to a first preset voltage value. If so, the first parallel mode is entered; otherwise, the second parallel mode is entered.

[0061] It should be noted that the first parallel mode and the second parallel mode here are only for distinguishing two different parallel modes and have no priority or other special meanings. Those skilled in the art can also set the name of the parallel mode according to needs.

[0062] In the above technical solution, by obtaining the internal and external pressure difference of the current battery pack and setting the first preset voltage value as the judgment condition, this mode can ensure that the parallel operation is performed only when the internal and external pressure difference of the battery pack is within a safe range. This effectively avoids safety risks such as current circulation, battery overheating and even short circuit that may be caused by excessive pressure difference, thereby significantly improving the safety of the parallel process; according to the different internal and external pressure differences, this mode can intelligently choose to enter the first parallel mode or the second parallel mode. This design makes the parallel process more flexible and can make the best decision according to different situations, thereby ensuring that the battery system can operate efficiently and stably under various working conditions.

[0063] Furthermore, the first parallel mode includes: Get the current operating status of the battery system.

[0064] If the operating state is an idle state, the charging MOS corresponding to the current battery pack is disconnected, and the corresponding discharging MOS is closed.

[0065] In some embodiments, the system is in an idle state, the charging MOS is disconnected, and the discharging MOS is closed; the voltage difference V_diff inside and outside the battery pack is large, and after waiting for the system charging and discharging state to switch, it jumps to the corresponding parallel process.

[0066] If the operating state is the charging state, the discharge MOS and the charging current limiting module corresponding to the current battery pack are closed, and the internal and external pressure difference of the current battery pack is detected in real time. When the internal and external pressure difference is less than the first preset voltage value, the charging MOS corresponding to the current battery pack is closed, and the charging current limiting module is disconnected to complete the parallel operation.

[0067] In some embodiments, the system is in a charging state, the discharge MOS is closed, the charging current limiting module is closed, and the charging current limiting module limits the charging current to, for example, 10A, to prevent the high-voltage battery pack on the bus from triggering a discharge overcurrent fault due to the need to discharge the low-voltage battery pack or the low-voltage battery pack from triggering a charging overcurrent fault; when the total internal and external voltage of the battery pack is less than 0.8V, the charging MOS is closed, the charging current limiting module is disconnected, and the battery pack completes parallel operation.

[0068] If the operating state is the discharge state, the discharge MOS corresponding to the current battery pack is closed, and the corresponding charging MOS is disconnected at the same time, and the internal and external pressure difference and the battery pack current of the current battery pack are detected in real time. When the internal and external pressure difference is less than or equal to the second preset voltage value or the battery pack current is greater than or equal to the preset current value, the charging MOS corresponding to the current battery pack is closed to complete the parallel operation.

[0069] In some embodiments, the system is in a discharging state, the discharging MOS is closed, the charging MOS is disconnected, and the discharging current passes through the charging MOS diode D2 to prevent the high-voltage battery pack in the system from charging the current battery pack and triggering an overcurrent fault; determine whether the pressure difference V_diff inside and outside the battery pack is less than or equal to 0.2V or whether the discharge current is greater than or equal to 2A; if not, there is still a large pressure difference inside and outside the system; if so, the pressure difference inside and outside the system is close, close the charging MOS, and complete the parallel operation.

[0070] In the above technical solution, in the charging state, the discharge MOS and the charging current limiting module are closed to effectively control the charging current and ensure the safety and stability of the charging process. The charging MOS is closed only when the internal and external pressure difference is less than the first preset voltage value to ensure that the parallel connection is completed within a safe range. This strategy can effectively avoid overload and battery damage during charging; in the discharge state, dual monitoring (internal and external pressure difference and current) provides a more stringent safety mechanism for parallel connection, which not only ensures the stability of the battery system, but also improves the reliability of smoothly connecting the battery pack to the overall system.

[0071] Furthermore, the second parallel mode includes: Get the current operating status of the battery system.

[0072] If the operating state is an idle state or a charging state, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

[0073] If the operating state is the discharge state, the discharge MOS corresponding to the current battery pack is closed, and the internal and external pressure difference and the battery pack current of the current battery pack are detected in real time. When the internal and external pressure difference is less than the second preset voltage value or the battery pack current is greater than the preset current value, the charging MOS corresponding to the current battery pack is closed to complete the parallel operation.

[0074] In some embodiments, the system is in a discharge state and the discharge MOS is closed; in the discharge state, when the internal and external pressure difference V_diff is less than a second preset voltage value such as 0.2V or the battery current I_BAT is greater than a preset current value, the current battery pack voltage is close to the system voltage, the charging MOS is closed, and the circulation between the battery packs will not trigger an overcurrent fault, and the parallel operation is completed.

[0075] The preset current value is, for example, 2A, and those skilled in the art may also set it to other values ​​according to actual application requirements, and is not limited to 2A.

[0076] In the above technical solution, for different operating states, the mode can automatically adjust to the corresponding parallel operation strategy to give full play to the battery performance. For example, in the charging state, the system can be quickly connected in parallel to further improve the battery charging efficiency. In the discharging state, the discharge MOS is closed and the internal and external pressure difference and the battery pack current are monitored in real time to ensure that the parallel operation is carried out within a safe range. Through the set conditions (monitoring of pressure difference and current), safety hazards caused by abnormal conditions are effectively avoided, thereby enhancing the safety of operation.

[0077] Embodiment 2: See also Figure 4 The present application also provides a battery management system, which loads and executes the battery pack parallel connection method described in Example 1; the battery management system at least includes: The judging module is used to obtain the bus voltage and judge whether the bus voltage is within a preset voltage range, so as to enter the first parallel module when the bus voltage is within the preset range.

[0078] The first parallel module is used to obtain the current battery pack voltage and determine whether the current battery pack voltage is greater than the bus voltage. If so, it enters a high-voltage access to low-voltage parallel mode; otherwise, it enters a low-voltage access to high-voltage parallel mode.

[0079] The relevant parallel strategies in the high voltage access to low voltage parallel mode and the low voltage access to high voltage parallel mode are as described in the first embodiment, and will not be described in detail here.

[0080] In the above technical solution, intelligent management of voltage is realized to ensure that the system responds quickly to voltage fluctuations, maintains voltage stability, and improves system reliability and stability; the first parallel module flexibly selects the parallel mode of high voltage access to low voltage or low voltage access to high voltage based on the comparison between the current battery pack voltage and the bus voltage. This strategy can dynamically adjust the parallel mode according to actual conditions to ensure that the system can operate efficiently under different voltage conditions; by intelligently selecting the parallel mode, the system can maximize the use of battery pack voltage differences, optimize energy transmission paths, reduce energy losses, and improve overall system efficiency.

[0081] Furthermore, the judgment module is also used to enter the second parallel module when the bus voltage is not within a preset range; the second parallel module is used to obtain the charging MOS and discharging MOS corresponding to the battery pack with the highest bus voltage and close them.

[0082] In the above technical solution, when the bus voltage exceeds the preset range, the system can quickly switch to the second parallel module, immediately obtain the battery pack with the highest voltage and close its charging MOS and discharging MOS, thereby quickly increasing the bus voltage and ensuring that the system quickly returns to normal working state; this design realizes automatic voltage adjustment and can dynamically switch according to voltage conditions without human intervention, thereby improving the intelligence level and response speed of the system.

[0083] Embodiment three: See also Figure 2 The present application also provides an energy storage system, which includes a plurality of battery systems connected in parallel on an energy storage bus, and the battery packs corresponding to each battery system are paralleled using the battery pack paralleling method described in Example 1.

[0084] Embodiment 4: The present application also provides a storage medium on which at least one computer instruction is stored. When the at least one computer instruction is executed by a processor, the battery pack parallel connection method described in Example 1 is implemented.

[0085] In some embodiments, the storage medium stores several computer programs for enabling the battery management system to execute all or part of the steps of the method described in various embodiments of the present application.

[0086] The storage medium may include a U disk, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk or an optical disk, and other media that can store program codes.

[0087] In summary, the present application provides a battery pack parallel method, a battery management system, an energy storage system and a storage medium; first, the bus voltage is obtained, and it is determined whether the bus voltage is within a preset voltage range; when the bus voltage is within the preset voltage range, the current battery pack voltage is obtained, and it is determined whether the current battery pack voltage is greater than the bus voltage. If it is greater, the high voltage is connected to the low voltage parallel mode; otherwise, the low voltage is connected to the high voltage parallel mode. The present application can solve the current circulation problem, and the system parallel can be completed under any working conditions.

[0088] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0089] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0090] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of the units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0091] The various component embodiments of the present application can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all functions of some modules according to the embodiments of the present application. The application can also be implemented as a device program (e.g., computer program and computer program product) for executing a part or all of the methods described herein. Such a program implementing the present application can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0092] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0093] Although the description of the present application is carried out in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes based on the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. A battery pack parallel connection method, characterized in that: The following steps are involved: Obtaining a bus voltage, and determining whether the bus voltage is within a preset voltage range; When the bus voltage is within the preset voltage range, the current battery pack voltage is obtained, and it is determined whether the current battery pack voltage is greater than the bus voltage. If so, the high voltage access to low voltage parallel mode is entered; otherwise, the low voltage access to high voltage parallel mode is entered.

2. The battery pack parallel connection method according to claim 1, characterized in that: The high voltage connected to low voltage parallel mode includes: Obtaining the current operating state of the battery system; wherein the operating state includes at least an idle state, a charging state, and a discharging state; If the operating state is an idle state, the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than a first preset voltage value, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation; If the operating state is the charging state, the discharge MOS corresponding to the current battery pack is disconnected, and the corresponding charging MOS is closed at the same time, and the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than or equal to the second preset voltage value, the discharge MOS corresponding to the current battery pack is closed to complete the parallel operation; If the operating state is the discharge state, the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than or equal to the second preset voltage value, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation.

3. The battery pack parallel connection method according to claim 2, characterized in that: The low voltage connected to high voltage parallel mode includes: The current internal and external pressure difference of the battery pack is obtained, and it is determined whether the internal and external pressure difference is greater than or equal to a first preset voltage value. If so, the first parallel mode is entered; otherwise, the second parallel mode is entered.

4. The battery pack parallel connection method according to claim 3, characterized in that: The first parallel mode includes: Get the current operating status of the battery system; If the operating state is an idle state, disconnect the charging MOS corresponding to the current battery pack, and close the corresponding discharging MOS; If the operating state is the charging state, the discharge MOS and the charging current limiting module corresponding to the current battery pack are closed, and the internal and external pressure difference of the current battery pack is detected in real time, so that when the internal and external pressure difference is less than the first preset voltage value, the charging MOS corresponding to the current battery pack is closed, and the charging current limiting module is disconnected to complete the parallel operation; If the operating state is the discharge state, the discharge MOS corresponding to the current battery pack is closed, and the corresponding charging MOS is disconnected at the same time, and the internal and external pressure difference and the battery pack current of the current battery pack are detected in real time. When the internal and external pressure difference is less than or equal to the second preset voltage value or the battery pack current is greater than or equal to the preset current value, the charging MOS corresponding to the current battery pack is closed to complete the parallel operation.

5. The battery pack parallel connection method according to claim 3, characterized in that: The second parallel mode includes: Get the current operating status of the battery system; If the operating state is an idle state or a charging state, the charging MOS and the discharging MOS corresponding to the current battery pack are closed to complete the parallel operation; If the operating state is the discharge state, the discharge MOS corresponding to the current battery pack is closed, and the internal and external pressure difference and the battery pack current of the current battery pack are detected in real time. When the internal and external pressure difference is less than the second preset voltage value or the battery pack current is greater than the preset current value, the charging MOS corresponding to the current battery pack is closed to complete the parallel operation.

6. The battery pack parallel connection method according to claim 1, characterized in that: When the bus voltage is not within a preset voltage range, the method includes: The charging MOS and discharging MOS corresponding to the battery pack with the highest bus voltage are obtained and closed.

7. A battery management system, characterized in that: The battery management system loads and executes the battery pack parallel connection method according to any one of claims 1 to 6; The battery management system at least comprises: A judgment module, used for obtaining a bus voltage and judging whether the bus voltage is within a preset voltage range, so as to enter a first parallel module when the bus voltage is within the preset range; The first parallel module is used to obtain the current battery pack voltage and determine whether the current battery pack voltage is greater than the bus voltage. If so, it enters a high-voltage access to low-voltage parallel mode; otherwise, it enters a low-voltage access to high-voltage parallel mode.

8. The battery management system according to claim 7, characterized in that: The judgment module is also used to enter the second parallel module when the bus voltage is not within a preset range; The second parallel module is used to obtain the charging MOS and discharging MOS corresponding to the battery pack with the highest bus voltage and close them.

9. An energy storage system, characterized in that: The energy storage system includes a plurality of battery systems connected in parallel on an energy storage bus, and the battery packs corresponding to each battery system are connected in parallel using the battery pack parallel connection method as described in any one of claims 1 to 6.

10. A storage medium having at least one computer instruction stored thereon, characterized in that: When the at least one computer instruction is executed by the processor, the battery pack parallel connection method as described in any one of claims 1-6 is implemented.

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