Parallel battery management method and system

Abstract

The invention belongs to the technical field of battery management, and particularly relates to a parallel battery management method and system, and the method comprises the steps: S1, enabling a plurality of battery packs to be connected in parallel, and then connecting the battery packs to a load; s2, each battery pack periodically receives data of other battery packs through a BMS of the battery pack and periodically sends the data of the battery pack of the battery pack, and then analyzes the data to obtain an analysis result; s3, judging whether one SOC of each battery pack is higher than a first threshold value or not according to an analysis result; if yes, selecting a high-capacity priority mode; and if not, selecting a parallel power supply mode. According to the invention, through interaction of the data among the battery packs, the battery packs can switch different power supply modes, so that the cruising ability of the battery packs is improved, and the service life of the battery packs is guaranteed.

Description

Technical Field

[0001] This invention belongs to the technical field of battery management, specifically relating to a parallel battery management method and system. Background Technology

[0002] In battery swapping applications for two-wheeled or three-wheeled vehicles, each replaceable battery pack must not be too heavy. Therefore, to meet the requirements for range and power output, two, three, or even more battery packs are often used on a single vehicle in parallel or series. However, each battery pack may have different remaining capacity and voltage during charging and discharging. Direct parallel connection cannot increase capacity, especially for lithium battery packs. Direct parallel connection would cause current to flow from the higher-voltage battery pack to the lower-voltage battery pack, which could severely burn out the battery pack's circuitry or the battery pack itself.

[0003] Currently, the market mainly uses the following four methods to improve the range and power of two-wheeled or three-wheeled vehicles by using multiple lithium battery packs: 1) Series Connection: This method connects two battery packs in series, significantly increasing the voltage and thus the overall capacity, as seen in Gogoro's battery swapping system. This method requires both battery packs to be swapped and used simultaneously; if one pack is depleted, the vehicle's operation will be affected. For this series connection method, due to the significantly increased voltage, other electrical systems in the vehicle need to be adjusted accordingly. Furthermore, this method requires the full capacity of the batteries and cannot operate with a single pack. It also places a burden on battery swapping stations, as all battery packs need to be replaced simultaneously during a swap.

[0004] 2) Manual switching: Switching between different battery packs to increase range via an air switch or by plugging and unplugging the battery pack's power bus. Manual switching is a relatively primitive method, requiring the vehicle to be stopped, which is obviously inconvenient.

[0005] 3) Switching method: A switch (or power divider) is added directly between the battery pack and the load. This device determines how the battery packs are connected to the load. A safer and more reliable design is to add a switch between multiple battery packs and the load, automatically switching one or more battery packs to the load according to a certain strategy. However, this method requires the installation of a switch, increasing the operating cost.

[0006] 4) Simple parallel connection method: A diode-like unidirectional conduction circuit is implemented using dual MOSFETs connected back-to-back in the BMS (Battery Management System). This allows multiple battery packs to be directly connected in parallel and prevents backflow. However, this method does not consider SOC (State of Charge) or battery characteristics at different SOC levels, and cannot intelligently handle battery swapping scenarios or protect the batteries.

[0007] Therefore, there is an urgent need to propose a new technical solution to address the above problems. Summary of the Invention

[0008] One of the objectives of this invention is to provide a parallel battery management method to address the shortcomings of existing technologies. This method enables each battery pack to switch between different power supply modes by exchanging data between the battery packs, thereby improving the battery pack's range and ensuring its lifespan.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A parallel battery management method includes the following steps: S1. Connect multiple battery packs in parallel to the load; S2. Each battery pack receives data from other battery packs and sends its own data to its own battery pack at regular intervals through its own BMS, and then analyzes the data to obtain the analysis results. S3. Based on the analysis results, determine whether the SOC of each battery pack is higher than the first threshold; if so, select the high capacity priority mode. If not, then select the parallel power supply mode.

[0010] Preferably, the method further includes step S4, whereby when a new battery pack is connected, its BMS first detects whether there is voltage on the power bus. If there is voltage, it obtains the data of each battery pack through the communication bus and sends its own battery pack data at regular intervals.

[0011] Preferably, in step S4, if there is no voltage on the power bus, the pre-amplifier circuit is turned on, and power is supplied to the power bus, and data of its own battery pack is sent periodically.

[0012] Preferably, in step S4, the BMS of the first connected battery pack will determine whether the type of the current battery pack is the same as the type of other battery packs based on the data of each battery pack. If not, it will not participate in parallel power supply.

[0013] Preferably, in step S4, if a battery pack that is currently supplying power is disconnected, each BMS will select a new battery pack to supply power based on the data of each battery pack within n time intervals, where 2≤n≤5.

[0014] Preferably, in step S4, if the SOC of the newly connected battery pack is higher than the SOC of the battery pack currently supplying power by a certain value, then the newly connected battery pack is selected for power supply.

[0015] Preferably, in step S4, if the battery pack is replaced for power supply, the current value of the previously powered battery pack needs to be detected. If the current value exceeds the backflow threshold, the power supply of the previously powered battery pack is cut off.

[0016] Preferably, in the high-capacity priority mode, if the SOC of the battery pack with the second highest SOC is higher than the SOC of the battery pack in power supply by a certain value, then the system switches to the battery pack with the second highest SOC.

[0017] Preferably, in step S1, after connecting to the load, power shortage monitoring is started. Each BMS monitors the total number of battery packs and the status of each battery pack. If the SOC of each battery pack is lower than the first threshold, it switches to parallel power supply mode. If the current BMS detects that the SOC of its own battery pack is lower than the second threshold, it stops supplying power to this battery pack.

[0018] The second objective of this invention is to provide a parallel battery management system, comprising: multiple battery packs connected in parallel to each other via a power bus and connected in parallel to a load; each battery pack includes a battery cell and a battery management system (BMS); the battery cell and the BMS are electrically connected; the battery cells of each battery pack are electrically connected to the power bus; the BMS of each battery pack are electrically connected to a communication bus; the BMS periodically receives data from other battery packs and periodically sends data from its own battery pack via the communication bus; and the BMS is equipped with a pre-amplification circuit.

[0019] The beneficial effects of this invention are as follows: This invention includes the following steps: S1, connecting multiple battery packs in parallel to a load; S2, each battery pack periodically receiving data from other battery packs and periodically sending its own data via its own BMS, then analyzing the data to obtain analysis results; S3, determining whether the SOC of each battery pack exceeds a first threshold based on the analysis results; if so, selecting a high-capacity priority mode; otherwise, selecting a parallel power supply mode. This invention uses a communication bus to exchange data between battery packs, enabling each battery pack to switch between different power supply modes, thereby improving the battery pack's endurance and ensuring its lifespan. Attached Figure Description

[0020] Figure 1 This is a flowchart of the parallel battery management method in Embodiment 1 of the present invention.

[0021] Figure 2 This is a schematic diagram of the overall structure of the parallel battery management system in Embodiment 2 of the present invention.

[0022] The components are: 1. Battery pack; 11. Battery cell; 12. BMS; 121. Pre-discharge circuit; 122. Pre-discharge MOSFET; 123. Power supply MOSFET; 2. Power bus; 3. Load; 4. Communication bus. Detailed Implementation

[0023] Where certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components by differences in name, but rather by differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." In this invention, unless otherwise explicitly specified and limited, terms such as "installed," "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] The following is in conjunction with the appendix Figures 1-2 The present invention will be further described in detail with reference to specific embodiments, but this is not intended to limit the present invention.

[0025] Parameter definitions of this invention: 1) CAN-ID base The base address of the CAN ID used for communication between the various battery packs is defined as a constant parameter by the program. 2) CAN-ID offet The offset of the CAN ID, dynamically obtained by each BMS. A complete CAN ID includes the CAN-ID. base +CAN-ID offet For a standard frame, the CAN address is 11 bits, the base address is 8 bits, and the offset is 3 bits, while the extended frame address is 29 bits long, the base address uses 26 bits, and the offset uses 3 bits. 3) SOC: Remaining capacity of the battery pack, ranging from 0% to 100%; 4) I bmax Battery pack reverse current threshold, usually a negative number; if a battery pack detects that the current has reached this threshold, the output needs to be shut off. 5) SOC low This refers to a lower level of remaining power threshold. At this level, the internal resistance of the battery pack will be relatively high, and the amplification current will be insufficient. However, it also allows for the direct parallel connection of several battery packs with similar SOC to increase the output current. 6) SOC vlowThis refers to an extremely low remaining power threshold. At this point, to protect the battery pack, the battery pack is no longer allowed to participate in discharging if its power level is below this value. 7) T pint The CAN ID packet transmission interval can generally be set to 1 second, meaning that each battery pack on the bus must periodically send a data packet containing the current parameters at this time.

[0026] Example 1 A parallel battery management method, comprising: Multiple battery packs are connected in parallel to each other via a power bus and are also connected in parallel to the load. Each battery pack includes battery cells and a BMS. The battery cells and BMS are electrically connected. The battery cells of each battery pack are electrically connected to the power bus, and the BMS of each battery pack is electrically connected to the communication bus. The BMS receives data from other battery packs and sends data from its own battery pack at regular intervals via the communication bus. The communication bus is a CAN bus, and the BMS is equipped with a pre-amplifier circuit. The battery pack connectors are equipped with B+ power lines, B- power lines, and a CAN bus. The B+ power line indicates the positive output of the battery pack, and the B- power line indicates the negative output. The power lines and CAN buses of each battery pack are connected one-to-one. The input of the pre-discharge circuit is connected to the battery cell via a pre-discharge MOSFET, and the output is connected to the load. The pre-discharge circuit is a current-limiting circuit to prevent arcing and damage to the connectors when the load has capacitance. The BMS is electrically connected to the switch of the pre-discharge MOSFET, controlling its switching. A power supply MOSFET is located between the battery cell and the load. The input of the power supply MOSFET is connected to the battery cell. The core is electrically connected, with the output of the power supply MOSFET connected to the load. The circuit consisting of the pre-discharge circuit and the pre-discharge MOSFET is connected in parallel with the power supply MOSFET. The BMS and the power supply MOSFET are connected via a switch. Both the pre-discharge MOSFET and the power supply MOSFET are integrated into the BMS. When a load is connected, the pre-discharge MOSFET is turned on first. This way, even if the load has a large capacitance, a small current will initially charge the capacitor, and the voltage will gradually increase. Then, the power supply MOSFET is turned on, and there is no voltage difference, thus preventing arcing. The data refers to a data packet containing parameters such as battery pack voltage, current, and SOC. The data packet is 8 bytes (64 bits in total) and contains the following information: A) Connection status: Size: 1 bit, 0: disconnected, 1: powered; B) SOC: Size: 7 bits, current battery pack capacity, unit: %, range: 0%~100%; C) Current voltage: Size: 12 bits, Unit: V, Range: +0.1V~+400.0V; D) Current: Size: 10 bits, Unit: A, Range: -255A~+255A; E) Cell type: Size: 2 bits, 01: ternary lithium, 10: lithium iron phosphate, 11: sodium battery; F) Battery pack model: Size: 8 bits, representing a combination code of serial number and capacity, defined uniformly by the manufacturer; G) Current temperature: Size: 8 bits, Unit: degrees Celsius, Range: -127℃~+127℃; H) BMS serial number: Size: 16 bits, factory unique code.

[0027] The method includes the following steps: S1. Connect multiple battery packs in parallel to the load; S2. Each battery pack periodically receives data from other battery packs and periodically sends its own data through its own BMS. Then, it analyzes the data, which refers to the data from other battery packs and its own battery pack, and obtains the analysis results. S3. Based on the analysis results, determine whether the SOC of each battery pack is higher than the first threshold; if so, select the high capacity priority mode; if not, select the parallel power supply mode. S4. When a new battery pack is connected, its BMS will first check whether there is voltage on the power bus. If there is voltage, it will return to step S2, that is, obtain the data of each battery pack through the communication bus, decide when to start the battery pack to provide power based on the data, and send its own battery pack data through the communication bus at regular intervals. If there is no voltage on the power bus, the pre-amplifier circuit will be turned on, and the communication bus will be powered, and its own battery pack data will be sent through the communication bus at regular intervals.

[0028] Define each BMS using CAN-ID base +CAN-ID offet CAN-ID sends data packets to the communication bus using its own address. base The offset CAN-ID is hardcoded in the program, so all BMSs are the same. offet It is automatically generated. The offset generation rule is: the offset of the first battery pack on the communication bus is 0, the second is 1, and so on, up to a maximum of the 8th. When a BMS connects to the communication bus, it first listens for CAN-ID on the communication bus. base All data packets are monitored to determine how many battery packs are connected on the communication bus, and the listening interval exceeds 3 times the T. pint Time. After monitoring data from all battery packs, determine the current BMS CAN-ID. offset Then, it periodically sends data packets with its own ID, with an interval of T. pint T pintThe data packet sending interval is set to 1 second, meaning that each battery pack on the bus must periodically send a data packet containing the current battery pack parameters at this time.

[0029] In this embodiment, when a battery pack is connected for the first time, its own BMS will determine whether the type of the current battery pack is consistent with the types of other battery packs based on the data of each battery pack. If not, it will not participate in parallel power supply. Connection refers to electrically connecting the power lines of the newly connected battery pack to the power bus composed of the power lines of other battery packs, and electrically connecting its own CAN bus to the communication bus composed of the CAN buses of other battery packs. The comparison type compares the battery pack type and battery pack model. If the comparison fails, the new battery pack is not allowed to connect to the power bus, that is, the new battery pack is not allowed to supply power, which can avoid parallel connection of different types of battery packs and cause circuit failure.

[0030] In this embodiment, if a currently powered battery pack is disconnected, each BMS will select a new battery pack to power the device based on data from each battery pack within n time intervals, where 2 ≤ n ≤ 5. For example, n can be 2, 3, 4, or 5. While powered on, it is permissible to insert or remove the battery pack connector. For battery packs not currently powered, operation is not affected. Only disconnecting the connector of the currently outputting battery pack will affect the device's operation, but this will only be temporary (nT) after a short period. pint If the power supply is interrupted after a certain period of time (i.e., when the user removes the battery pack that is currently providing power), power can be restored. This setting prevents power supply from being interrupted when the user removes the battery pack, thus improving power supply efficiency.

[0031] In this embodiment, if the SOC of a newly connected battery pack is higher than the SOC of the currently powered battery pack by a certain threshold, the newly connected battery pack is selected for power supply. Priority is given to battery packs with higher SOC and voltage. After a battery pack with a higher SOC is connected to the power bus and communication bus, if it is found that the current battery pack has the highest SOC and is 5% higher than the SOC of the currently powered battery pack, then power is immediately supplied to the power bus. The specific threshold can be set according to actual conditions, for example, it can also be 6%, 7%, or 8%.

[0032] In this embodiment, if the battery pack is replaced for power supply, the current value passing through the previously powered battery pack needs to be detected. If the current value exceeds the reverse current threshold, the power supply to the previous battery pack is cut off. If multiple battery packs were previously powered, the current value passing through each of them needs to be detected. If the current value of any battery pack exceeds the reverse current threshold, the power supply to that battery pack is cut off. After replacing the power supply battery pack, the battery pack that previously supplied power to the power bus may experience reverse current. In this case, if the current exceeds the reverse current threshold, the external power supply is cut off, and the new battery pack with the highest SOC provides power, while the battery pack itself withdraws from power supply. Battery pack reverse current threshold I bmax If set to a negative number, the battery pack will detect that the current has reached this threshold and will need to shut down the output.

[0033] In this embodiment, in the high-capacity priority mode, if the SOC of the battery pack with the second-highest SOC is higher than the SOC of the battery pack currently supplying power by a certain threshold, then the power supply is switched to the battery pack with the second-highest SOC. As the battery pack with the highest SOC begins to consume power, its SOC gradually decreases, and the battery pack with the second-highest SOC prepares to take over the current power supply. When the SOC of the second-highest battery pack is higher than the SOC of the battery pack currently supplying power by a certain threshold, it is connected to the bus power supply. Similarly, if there is backflow of current, the battery pack currently supplying power will disconnect from the power supply. The threshold is 5%, and the specific threshold can be set according to the actual situation, for example, it can also be 6%, 7%, or 8%. This setting can effectively balance the SOC of each battery pack, avoid excessively high voltage in a single battery pack, and improve the power supply efficiency.

[0034] In this embodiment, in the high-capacity priority mode, if the SOC of each battery pack is lower than the first threshold, the system switches to parallel power supply mode. When the SOC of each battery pack is lower than the first threshold, multiple battery packs are allowed to supply power in parallel if their SOCs are not significantly different. For example, if the difference between two battery packs is less than a certain value (5%), these two battery packs can be allowed to supply power in parallel, thereby ensuring a larger output current.

[0035] In this embodiment, power shortage monitoring is initiated after connection to the load. Power shortage monitoring is continuously activated during the power supply process. Each BMS monitors the total number of battery packs and the status of each battery pack. If the SOC of all battery packs is lower than a first threshold, the system switches to parallel power supply mode. If the current BMS detects that the SOC of its own battery pack is lower than a second threshold, it stops supplying power to that battery pack. The first threshold is SOC. low This refers to a lower remaining charge threshold, at which point the battery pack's internal resistance is higher, resulting in insufficient amplification current. The first threshold is the State of Charge (SOC). low It can be set according to the actual situation, for example, it can be set to 30%; the second threshold SOC vlowThe first threshold refers to an extremely low remaining battery capacity. At this threshold, to protect the battery pack, the battery pack is no longer allowed to discharge below this value. The second threshold is the State of Charge (SOC). vlow It can be set according to the actual situation; for example, it can be set to 5%.

[0036] This invention, through careful design of the BMS's external interface and operating logic, enables the direct parallel output of multiple (up to eight) battery packs of the same specifications without increasing BMS hardware costs or altering other vehicle electrical architectures. This allows for intelligent power allocation among the multiple battery packs, thereby meeting the vehicle's range and power output requirements. Simultaneously, because it uses the battery packs' CAN bus for communication, other devices on the vehicle's connected bus (merging the communication bus and power bus into a single bus), such as instrument clusters, motor controllers, and ECU / VCUs, can receive status information from each battery pack and take appropriate actions. For example, the instrument cluster can display the charge level of each battery pack, and the motor control system can obtain battery pack information to adjust the power strategy, improving the battery pack's power supply efficiency.

[0037] This invention coordinates the status of each battery pack through CAN bus and voltage monitoring, achieving power conversion and avoiding current backflow caused by directly connecting battery packs in parallel. It allows battery packs in different operating states to be used simultaneously, including replacing one battery pack during battery swapping, and allowing multiple battery packs with different voltages and SOCs to operate normally in a single vehicle. It supports situations where the vehicle's battery packs are not fully configured; for example, a vehicle requiring three battery packs may only have two installed, or vice versa. The carefully designed CAN bus communication protocol and hardware detection specifications enable the BMS to intelligently handle these switching scenarios and meet usage requirements. Other components in the vehicle are connected to the CAN bus and can also obtain the status of each battery pack to perform actions such as display, control, and alarms. All battery packs periodically send their own status data packets, allowing other vehicle components to obtain the status information of each battery pack and take appropriate actions.

[0038] Example 2 A parallel battery management system, based on the parallel battery management method of Embodiment 1, includes: multiple battery packs 1 connected in parallel to each other via a power bus 2 and connected in parallel to a load 3. Each battery pack 1 includes a cell 11 and a battery management system (BMS) 12, which are electrically connected. The cells 11 of each battery pack 1 are electrically connected to the power bus 2, and the BMS 12 of each battery pack 1 is electrically connected to a communication bus 4. The BMS 12 periodically receives data from other battery packs 1 and periodically sends data from its own battery pack 1 via the communication bus 4. The communication bus 4 is a CAN bus. The BMS 12 is equipped with a pre-discharge circuit 121. The input terminal of the pre-discharge circuit 121 is connected to the cell 11 via a pre-discharge MOSFET 122, and the output terminal of the pre-discharge circuit 121 is connected to the load 3. The pre-discharge circuit 121 is a current-limiting circuit to prevent arcing and damage to connectors when the load 3 has capacitors. The BMS12 and the pre-discharge MOSFET 122 are electrically connected. The BMS12 controls the switching of the pre-discharge MOSFET 122. A power supply MOSFET 123 is provided between the battery cell 11 and the load 3. The input terminal of the power supply MOSFET 123 is electrically connected to the battery cell 11, and the output terminal of the power supply MOSFET 123 is electrically connected to the load 3. The circuit composed of the pre-discharge circuit 121 and the pre-discharge MOSFET 122 is connected in parallel with the power supply MOSFET 123. The BMS12 and the power supply MOSFET 123 are electrically connected. Both the pre-discharge MOSFET 122 and the power supply MOSFET 123 are MOSFETs that are integrated into the BMS12. When the load 3 is connected, the pre-discharge MOSFET 122 is turned on first. In this way, even if the load 3 has a large capacitor, a small current will charge the capacitor in the early stage, and the voltage will gradually increase. Then the power supply MOSFET 123 is turned on, and there is no voltage difference, so there will be no arcing. Each BMS12 is equipped with a processor, which can be a microcontroller chip. Each processor is configured to execute a management program, which includes: Handshake state: The newly connected battery pack 1 obtains voltage data through the power bus 2, and determines whether other battery packs 1 are supplying power based on the voltage data. If there is voltage, it obtains the data of each battery pack 1 through the communication bus 4, and periodically sends its own battery pack 1 data; if there is no voltage, it turns on the preamplifier circuit 121, supplies power to the power bus 2, and periodically sends its own battery pack 1 data. When a battery pack 1 is connected to the vehicle's cable, it first needs to know if other battery packs 1 exist and whether the connection conditions are met. The newly connected battery pack 1 needs to monitor the voltage of the B+ power line to see if other battery packs 1 are supplying power, listen to the data on the communication bus 4 to determine if other devices are on the communication bus 4, and decide whether to supply power externally, which power supply mode to switch to, and send the current battery pack 1's data to the communication bus 4 based on the data analysis results. If there is no voltage on the B+ power line and no information about other battery packs 1 on the communication bus 4, it considers itself to be the first connected battery pack 1, and at this time, the pre-amplifier circuit 121 is turned on to supply power to the power bus 2. High capacity priority mode: When a battery pack 1 is connected to the communication bus 4, if it finds that it is the battery pack 1 with the highest SOC, it will prioritize power supply and output power. If there is only one battery pack 1 at this time, it will directly prioritize power supply. After the current battery pack 1 has been used for a period of time and the SOC decreases, it will switch to other battery packs with higher SOC or switch to parallel power supply mode. Parallel power supply mode: Multiple battery packs 1 are connected to the power bus 2 and communication bus 4. Currently, one high-SOC battery pack 1 is supplying power. At this time, low-SOC battery packs 1 cannot be connected in parallel to output power, otherwise current backflow will occur. However, as the high-SOC battery pack 1's power is consumed, and the SOC of all battery packs 1 falls below the first threshold, battery packs 1 with similar SOCs are allowed to supply power in parallel. Because the voltages are similar and the SOCs are essentially the same, current backflow will not occur.

[0039] Low power monitoring: Each BMS12 monitors the number of battery packs 1 connected to the communication bus 4 and the status of each battery pack 1. It protects the battery packs 1 by setting a second threshold. When the SOC of one battery pack 1 falls below the second threshold, that battery pack 1 is disconnected from power supply. This ensures that the vehicle's normal operation is not affected by situations such as battery shortage or battery replacement. If the low power monitoring detects that the output current or voltage is insufficient to meet the demand, even if the current mode is high-capacity priority, battery packs 1 with similar SOCs will be allowed to supply power in parallel.

[0040] Obviously, this invention includes the following steps: S1, connecting multiple battery packs in parallel to a load; S2, each battery pack periodically receiving data from other battery packs and periodically sending its own data via its own BMS, then analyzing the data to obtain analysis results; S3, determining whether the SOC of each battery pack exceeds a first threshold based on the analysis results; if so, selecting a high-capacity priority mode; otherwise, selecting a parallel power supply mode. This invention uses a communication bus to exchange data between battery packs, enabling each battery pack to switch between different power supply modes, thereby improving the battery pack's endurance and ensuring its lifespan.

[0041] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the invention is not limited to the specific embodiments described above, and any obvious improvements, substitutions, or modifications made by those skilled in the art based on this invention are within the scope of protection of this invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the invention.

Claims

1. A parallel battery management method, characterized in that, Includes the following steps: S1. Connect multiple battery packs in parallel to the load; S2. Each battery pack receives data from other battery packs and sends its own data to its own battery pack at regular intervals through its own BMS, and then analyzes the data to obtain the analysis results. S3. Based on the analysis results, determine whether the SOC of each battery pack is higher than the first threshold; if so, select the high capacity priority mode. If not, then select the parallel power supply mode.

2. The parallel battery management method as described in claim 1, characterized in that, It also includes step S4, where when a new battery pack is connected, its BMS will first detect whether there is voltage on the power bus. If there is voltage, it will obtain the data of each battery pack through the communication bus and send its own battery pack data at regular intervals.

3. The parallel battery management method as described in claim 2, characterized in that, In step S4, if there is no voltage on the power bus, the pre-amplifier circuit is turned on, and power is supplied to the power bus, and data of its own battery pack is sent periodically.

4. The parallel battery management method as described in claim 3, characterized in that, In step S4, for the first battery pack connected, its own BMS will determine whether the type of the current battery pack is the same as the type of other battery packs based on the data of each battery pack. If not, it will not participate in parallel power supply.

5. The parallel battery management method as described in claim 3, characterized in that, In step S4, if the battery pack that is currently supplying power is disconnected, each BMS will select a new battery pack to supply power based on the data of each battery pack within n time intervals, where 2≤n≤5.

6. The parallel battery management method as described in claim 3, characterized in that, In step S4, if the SOC of the newly connected battery pack is higher than the SOC of the battery pack currently supplying power by a certain value, then the newly connected battery pack is selected for power supply.

7. The parallel battery management method as described in claim 3, characterized in that, In step S4, if the battery pack is replaced for power supply, the current value of the previously powered battery pack needs to be detected. If the current value exceeds the backflow threshold, the power supply of the previous battery pack is cut off.

8. The parallel battery management method as described in claim 1, characterized in that, In the high-capacity priority mode, if the SOC of the battery pack with the second highest SOC is higher than the SOC of the battery pack in power supply by a certain value, then the system switches to the battery pack with the second highest SOC.

9. The parallel battery management method as described in claim 1, characterized in that, In step S1, after connecting to the load, power shortage monitoring is started. Each BMS monitors the total number of battery packs and the status of each battery pack. If the SOC of each battery pack is lower than the first threshold, it switches to parallel power supply mode. If the current BMS detects that the SOC of its own battery pack is lower than the second threshold, it stops supplying power to this battery pack.

10. A parallel battery management system, based on the parallel battery management method according to any one of claims 1 to 9, characterized in that, include: Multiple battery packs are connected in parallel to each other via a power bus and are also connected in parallel to a load. Each battery pack includes battery cells and a battery management system (BMS). The battery cells and the BMS are electrically connected. The battery cells of each battery pack are electrically connected to the power bus, and the BMS of each battery pack is electrically connected to a communication bus. The BMS periodically sends data from its own battery pack and periodically receives data from other battery packs via the communication bus. The BMS is equipped with a pre-amplification circuit.

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