Parallel battery pack protection method and device and storage medium

Abstract

The invention discloses a parallel battery pack protection method and device and a storage medium, and the method comprises the steps: obtaining the state information of all battery packs in a battery pack, and determining an abnormal battery pack; wherein the abnormal battery pack is in a self-protection state; the battery pack comprises a main battery pack and a plurality of slave battery packs; based on the protection type of the self-protection state, determining an enabled protection level; wherein the protection level comprises system-level protection and non-system-level protection; controlling the working authority of the battery pack required by the protection level, and executing a corresponding monitoring protection mode; wherein the work authority comprises a charging work authority and a discharging work authority. According to the invention, the work of each battery pack in the battery pack is autonomously coordinated through the main battery pack, and system-level protection can be provided under the condition of not increasing extra hardware equipment and cost.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method and device for protecting a parallel battery pack and a computer-readable storage medium. Background Art

[0002] Traditional multi-battery pack parallel systems usually rely on additional mechanical equipment or external control boards to manage and switch between packs, but this method has the following shortcomings:

[0003] (1) Additional hardware equipment is required, which increases the implementation cost of the multi-battery pack parallel system;

[0004] (2) Each battery pack is equipped with an independent battery management system (BMS), but it can only protect the battery pack itself and cannot comprehensively monitor and coordinate all battery packs in the entire multi-battery pack parallel system, and thus cannot achieve system-level protection. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a parallel battery pack protection method, device and computer-readable storage medium, which can provide system-level protection without adding additional hardware equipment and costs by autonomously coordinating the operation of each battery pack in the battery group through the main battery pack.

[0006] A first aspect of the present invention provides a method for protecting a parallel battery pack, which is performed by a main battery pack. The method includes:

[0007] Acquire status information of all battery packs in the battery pack, and determine abnormal battery packs; wherein the abnormal battery packs are in a self-protection state; the battery pack includes: the master battery pack and a plurality of slave battery packs;

[0008] Determine the enabled protection level based on the protection type of the self-protection state; wherein the protection level includes: system-level protection and non-system-level protection;

[0009] Control the working permissions of the battery pack required for the protection level and execute the corresponding monitoring protection mode; wherein the working permissions include: charging working permissions and discharging working permissions.

[0010] Optionally, controlling the working permissions of the battery pack required for the protection level and executing the corresponding monitoring protection mode include:

[0011] When the protection level is the system-level protection, removing the working permissions of all the battery packs;

[0012] After the system-level protection is released, the working authority of each battery pack in the battery group is reallocated according to the current charge and discharge strategy.

[0013] Optionally, controlling the working permissions of the battery pack required for the protection level and executing the corresponding monitoring protection mode include:

[0014] When the protection level is the non-system level protection, assigning work permissions to the remaining battery packs in the battery pack except the abnormal battery pack;

[0015] After the work authority allocation is completed and the work change of the remaining battery packs is completed, the work authority of the abnormal battery pack is removed.

[0016] Optionally, controlling the working permissions of the battery pack required for the protection level and executing the corresponding monitoring protection mode include:

[0017] When the protection level is the non-system level protection and the battery pack is discharging, determining whether all the battery packs currently being discharged are the abnormal battery packs, and whether there are any waiting battery packs in the battery pack;

[0018] If all of them are abnormal battery packs and there are waiting battery packs, then all of the abnormal battery packs are replaced with the waiting battery packs;

[0019] Otherwise, remove the working permissions of all abnormal battery packs.

[0020] Optionally, the method further comprises:

[0021] Based on all the state information, determining the operating state of the battery pack; wherein the operating state includes: a working state and an idle state;

[0022] When the battery pack is in the working state and the charging and discharging strategy is running, a charging and discharging protection mode is executed;

[0023] When the battery pack is in the idle state, a sleep protection mode is executed.

[0024] Optionally, when the battery pack is in the working state and the charge and discharge strategy is executed, the charge and discharge protection mode is executed, including:

[0025] Obtaining a first working battery pack queue currently running on the battery pack; wherein the first working battery pack queue includes N battery packs; N≥1;

[0026] Based on the charging and discharging strategy, obtaining a second working battery pack queue to be operated;

[0027] Compare the first working battery pack queue and the second working battery pack queue to determine a battery pack set to be changed;

[0028] Change the working permissions of each battery pack in the changed battery pack set.

[0029] Optionally, the changing the working permission of each battery pack in the battery pack set includes:

[0030] When the changed battery pack set includes only at least one battery pack to be added, assigning work permissions to the battery pack to be added;

[0031] When the changed battery pack set contains only M1 battery packs to be removed, the working permissions of the battery packs to be removed are removed; wherein M1 <N;

[0032] When the changed battery pack set includes at least one battery pack to be added and M2 battery packs to be removed, the work permissions of the battery pack to be removed are preferentially removed, and then the work permissions of the battery pack to be added are allocated; wherein M2 <N;

[0033] When the changed battery pack set includes at least one battery pack to be added and N battery packs to be removed, the charging switches of all the changed battery packs are turned off, and the discharging switch of at least one of the changed battery packs is turned on.

[0034] Optionally, turning off charging switches of all changed battery packs and turning on a discharging switch of at least one changed battery pack includes:

[0035] Turn off the charging switch of the battery pack to be removed and maintain the corresponding discharging switch state;

[0036] respectively starting a first timer for the battery pack to be removed and a second timer for the battery pack to be added;

[0037] After the second timer starts, assigning work permissions to the battery pack to be added, turning on the discharge switch of the battery pack to be added, and prohibiting turning on the corresponding charging switch;

[0038] When the first timer exceeds a first preset time, removing the working permission of the battery pack to be removed;

[0039] When the second timer counts more than a second preset time, the charging switch restriction of the battery pack to be added is released; wherein the second preset time is greater than the first preset time.

[0040] Optionally, when the battery pack is in the idle state, executing the sleep protection mode includes:

[0041] After notifying all the slave battery packs to enter sleep mode through internal communication, controlling the master battery pack to enter sleep mode; or

[0042] A battery pack is designated from the battery packs participating in the discharge operation to maintain the discharge operation, and the remaining battery packs in the battery group are controlled to enter dormancy.

[0043] A second aspect of the present invention provides a parallel battery pack protection device, comprising:

[0044] An information acquisition module, used to acquire status information of all battery packs in the battery pack and determine abnormal battery packs; wherein the abnormal battery packs are in a self-protection state; the battery pack includes: the master battery pack and a plurality of slave battery packs;

[0045] A protection level determination module, configured to determine an enabled protection level based on the protection type of the self-protection state; wherein the protection level includes: system-level protection and non-system-level protection;

[0046] The monitoring and protection execution module is used to control the working permissions of the battery pack required by the protection level and execute the corresponding monitoring and protection mode; wherein the working permissions include: charging working permissions and discharging working permissions.

[0047] An embodiment of the third aspect of the present invention provides a computer-readable storage medium, which includes a stored computer program; wherein, when the computer program is running, it controls the device where the computer-readable storage medium is located to execute the parallel battery pack protection method described in any one of the first aspects above.

[0048] Compared with the prior art, the embodiments of the present invention provide a parallel battery pack protection method, device and computer-readable storage medium, the method comprising: obtaining status information of all battery packs in a battery pack, and determining abnormal battery packs; wherein the abnormal battery packs are in a self-protection state; the battery pack comprises: a main battery pack and several slave battery packs; based on the protection type of the self-protection state, determining the enabled protection level; wherein the protection level comprises: system-level protection and non-system-level protection; controlling the working permissions of the battery packs required for the protection level, and executing the corresponding monitoring protection mode; wherein the working permissions comprise: charging working permissions and discharging working permissions. The present invention can provide system-level protection without adding additional hardware equipment and costs by autonomously coordinating the work of each battery pack in the battery pack through the main battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a flow chart of an embodiment of a parallel battery pack protection method provided by the present invention;

[0050] Figure 2is a schematic diagram of an embodiment of a battery pack provided by the present invention;

[0051] Figure 3 It is a schematic diagram of an embodiment of information aggregation and external coordination of a main battery pack provided by the present invention;

[0052] Figure 4 It is a flow chart of an embodiment of a monitoring protection mode corresponding to the system-level / non-system-level protection provided by the present invention;

[0053] Figure 5 It is a schematic diagram of an embodiment of performing system-level protection processing when overcurrent protection occurs in a battery pack provided by the present invention;

[0054] Figure 6 is a schematic diagram of an embodiment of a system state machine provided by the present invention;

[0055] Figure 7 It is a schematic diagram of an embodiment of performing non-system level protection processing when over-temperature protection occurs in a battery pack provided by the present invention;

[0056] Figure 8 is a schematic diagram of an embodiment of discharging a parallel battery pack provided by the present invention under different discharging strategies;

[0057] Fig. 9 is a schematic diagram of an embodiment of charging a parallel battery pack provided by the present invention under different charging strategies;

[0058] Fig.10 It is a flow chart of an embodiment of a charge-discharge protection mode corresponding to the operation of the charge-discharge strategy provided by the present invention;

[0059] Fig.11 is a flow chart of an embodiment of the present invention in which a battery pack to be removed is completely replaced;

[0060] Fig.12 is a schematic diagram of another embodiment of the present invention in which the battery pack to be removed is completely replaced;

[0061] Fig.13 is a flow chart of an embodiment of a battery pack provided by the present invention entering a dormant state;

[0062] Fig.14 It is a structural schematic diagram of a parallel battery pack protection device provided by the present invention. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this technical field without creative work are within the scope of protection of the present invention.

[0064] See also Figure 1 , is a flow chart of an embodiment of the parallel battery pack protection method provided by the present invention.

[0065] The first aspect of the present invention provides a parallel battery pack protection method, which is performed by a main battery pack. The method includes steps S1 to S3, which are as follows:

[0066] Step S1: obtaining status information of all battery packs in a battery pack, and determining an abnormal battery pack; wherein the abnormal battery pack is in a self-protection state; the battery pack comprises: the master battery pack and a plurality of slave battery packs;

[0067] Step S2: determining the enabled protection level based on the protection type of the self-protection state; wherein the protection level includes: system-level protection and non-system-level protection;

[0068] Step S3: Based on the working authority of the battery pack required to control the protection level, execute the corresponding monitoring protection mode; wherein the working authority includes: charging working authority and discharging working authority.

[0069] It should be noted that the embodiment of the present invention adopts a "one master and multiple slaves" working mode, so in a multi-battery pack parallel system, the battery pack includes a master battery pack and several slave battery packs. Before starting the multi-battery pack parallel system, it is necessary to assign roles to all battery packs, and select a master battery pack and multiple slave battery packs. Each battery pack has three functions: master role, slave role, and unconfigured role. The role type of each battery pack started is determined by the preset role allocation strategy; and at the factory, each battery pack defaults to an unconfigured role.

[0070] The battery pack is a whole formed by combining the battery cells in series and parallel, and then combined with the control board. The control board inside the battery pack has both BMS management functions (such as over-current, over-voltage and over-temperature protection for the battery pack itself) and parallel management functions, which can handle the management or collaborative work between parallel battery packs, such as Figure 2 shown.

[0071] In other words, any battery pack in the battery pack may be defined as the main battery pack. Once a battery pack is determined to be the main control role (i.e., the main battery pack), it not only has an independent BMS to monitor its own status, but can also participate in the parallel management of the entire multi-battery pack parallel system and coordinate the work of all battery packs in the battery pack. Therefore, when an abnormal battery pack appears, if the protection type corresponding to its self-protection state needs to be upgraded to system-level protection, the main battery pack will execute the corresponding monitoring and protection mode by controlling the working permissions of all battery packs (such as removing the working permissions of all battery packs in the battery pack in a preset order); if the protection type corresponding to its self-protection state only requires non-system-level protection, the main battery pack will execute the corresponding monitoring and protection mode by controlling the working permissions of some battery packs (such as changing the working permissions of some battery packs in the battery pack).

[0072] Specifically, the protection types corresponding to the system level include but are not limited to: main battery pack low power protection, device loss protection, system discharge overcurrent protection, system discharge overcurrent protection lock, system charge overcurrent protection, system charge overcurrent protection lock, system fault protection, and smart charger control fault protection. The protection types corresponding to the non-system level include: overtemperature protection. The status information of the battery pack includes but is not limited to: the self-protection status of each battery pack, alarm information (protection alarm notification), external communication status, voltage, current, charge (State of Charge, SOC), temperature, and charge and discharge function status.

[0073] It is worth noting that the main battery pack in the embodiment of the present invention is equivalent to the commander of the multi-battery pack parallel system and is unique in the entire system. Figure 3 As shown. On the one hand, the main battery pack can summarize the status information of all battery packs in the battery pack, coordinate and control the parallel operation of each battery pack from a global perspective, including but not limited to: executing charging and discharging strategies, executing corresponding protection modes, and managing the sleep and wake-up of battery packs; on the other hand, the main battery pack can be responsible for the working interaction with external devices, including: Electronic Control Unit (ECU), motor, instrument and smart charging gun.

[0074] See also Figure 4 , is a schematic diagram of an embodiment of a monitoring protection mode corresponding to system-level / non-system-level protection provided by the present invention.

[0075] In an optional embodiment, the control of the working permissions of the battery pack required for the protection level in the above step S3 and the execution of the corresponding monitoring protection mode include:

[0076] When the protection level is the system-level protection, removing the working permissions of all the battery packs;

[0077] After the system-level protection is released, the working authority of each battery pack in the battery group is reallocated according to the current charge and discharge strategy.

[0078] It should be noted that each battery pack is equipped with an independent BMS to ensure the safe operation of the battery pack itself. However, when multiple battery packs work in parallel, relying solely on the BMS inside each battery pack is not enough to ensure the safe operation of the entire multi-battery pack parallel system. In this case, the main battery pack manages and controls the operation of each battery pack in the battery pack to introduce system-level protection.

[0079] In order to more clearly describe the technical solution provided by the embodiments of the present invention, some specific embodiments are provided below for reference:

[0080] Example 1: Figure 4 As shown in the figure, when the slave 1 battery pack is abnormal, the slave 1 battery pack will be protected through its own BMS and enter the self-protection state. For example, when the output current of the slave 1 battery pack increases, the overcurrent protection is triggered. When protection occurs, the slave 1 battery pack sends a protection alarm notification through internal communication and reports it to the master battery pack. The master battery pack will obtain the status information of all battery packs in the battery pack in real time. Once the master battery pack receives the alarm information (protection alarm notification) and self-protection status information of the slave 1 battery pack (abnormal battery pack), the master battery pack will enter the system-level protection mechanism after determining that the protection type corresponding to the self-protection state of the abnormal battery pack needs to be upgraded to system-level protection. The master battery pack will remove the working permissions of all battery packs in the battery pack (i.e., charging working permissions and discharging working permissions); among them, the master battery pack will still maintain communication after removing the working permissions and obtain the status information of all battery packs in real time; after all slave battery packs remove the working permissions and stop charging and discharging, they need to wait for the master battery pack to assign working permissions again before they can participate in the work. In other words, after the working authority (i.e., charging and discharging working authority) is removed from the battery pack, its charging switch and discharging switch are both turned off, but the communication function is still retained within the slave battery pack to receive instructions from the master battery pack, such as receiving working authority instructions assigned by the master battery pack; similarly, after the working authority is removed from the master battery pack, its charging switch and discharging switch are both turned off, but the master battery pack still retains the parallel control function to control and manage the slave battery pack, such as controlling the removal of working authority from the slave battery pack or assigning working authority to the slave battery pack through internal communication.

[0081] The system-level protection can be released (restored) by releasing the self-protection state of the abnormal battery pack (such as delayed recovery) or removing the abnormal battery pack from the battery pack. After that, when the multi-battery pack parallel system is running again, the main battery pack will reallocate the working permissions of each battery pack in the battery pack according to the current charge and discharge strategy; it should be noted that not all battery packs in the battery pack will be assigned working permissions to participate in the operation of the charge and discharge strategy. Only the working battery pack queue determined by the charge and discharge strategy will be assigned working permissions.

[0082] Similarly, when the abnormal battery pack is the main battery pack, the main battery pack also enters the self-protection state and determines whether to enable system-level protection based on the protection type of the self-protection state; if so, the main battery pack's own working permissions (i.e., charging and discharging working permissions) are removed, the charging switch and the discharging switch are turned off, the parallel control function is retained, and all working permissions are removed from the battery pack through internal communication.

[0083] Example 2: Discharge overcurrent protection is usually triggered externally. Once the battery pack has overcurrent protection, all working battery packs in the battery pack must stop discharging. Figure 5 As shown in the figure, in a multi-battery pack parallel system, two battery packs in the battery pack are discharging. When the output current increases, one of the battery packs triggers overcurrent protection (enters self-protection state). Since this overcurrent protection type needs to be upgraded to system-level protection, under the control of the main battery pack, the discharge of all working battery packs in the battery pack is stopped, that is, the discharge switches of these battery packs are turned off (discharge work permission is removed).

[0084] It is worth noting that the protection types corresponding to the system-level protection include but are not limited to: main battery pack low power protection, device loss protection, system discharge overcurrent protection, system discharge overcurrent protection lock, system charging overcurrent protection, system charging overcurrent protection lock, system fault protection, and intelligent charger control fault protection; the corresponding monitoring protection modes include: main battery pack low power protection mode, device loss protection mode, system discharge overcurrent protection mode, system discharge overcurrent protection lock mode, system charging overcurrent protection mode, system charging overcurrent protection lock mode, system fault protection mode, and intelligent charger control fault protection mode, such as Figure 6 The protection types corresponding to system-level protection are as follows:

[0085] (1) Main battery pack low power protection:

[0086] Trigger: The main control battery pack is under-voltage and is insufficient to support the management of the parallel system;

[0087] Action: The system enters the main control low voltage protection mode and stops the overall discharge work;

[0088] Recovery: System charging allows the main controller to replenish power.

[0089] (2) Device loss protection:

[0090] Trigger: Offline from the battery pack;

[0091] Action: The system enters the device loss protection mode and stops the overall discharge and charging work;

[0092] Recovery: The system goes back online from the battery pack or the system reallocates roles.

[0093] (3) System discharge overcurrent protection:

[0094] Trigger: A battery pack has discharge overcurrent protection;

[0095] Action: The system enters the discharge overcurrent protection mode and stops the overall discharge operation;

[0096] Recovery: The discharge overcurrent protection of the battery pack is restored (delayed recovery).

[0097] (4) System discharge overcurrent protection lock:

[0098] Trigger: System-level discharge overcurrent protection occurs multiple times in succession;

[0099] Action: The system enters the discharge overcurrent protection lock mode, stops the overall discharge work, and cannot be restored with delay;

[0100] Recovery: Manual unlock or charging unlock.

[0101] (5) System charging overcurrent protection:

[0102] Trigger: A battery pack has overcurrent protection.

[0103] Action: The system enters the charging overcurrent protection mode and stops the overall charging operation;

[0104] Recovery: The battery pack’s charging overcurrent protection is restored (delayed recovery).

[0105] (6) System charging overcurrent protection lock:

[0106] Trigger: System-level charging overcurrent protection occurs multiple times in succession;

[0107] Action: The system enters the charging overcurrent protection lock mode, stops the overall charging work, and cannot be restored with delay;

[0108] Recovery: Manually unlock or remove the charger.

[0109] (7) System Fault Protection:

[0110] Trigger: A battery pack failure alarm occurs in the system;

[0111] Action: The system enters fault protection mode and stops discharging and charging;

[0112] Recovery: Remove the faulty battery pack and reassign the roles.

[0113] (8) Intelligent charger control fault protection:

[0114] Trigger: When the smart charger cannot control the current drop, such as when the working battery pack cannot adjust the current;

[0115] Action: The system enters the intelligent charger control fault protection mode, stops charging, and turns on the discharge function;

[0116] Resume: Delay recovery or remove charger.

[0117] In another optional embodiment, the control of the working permissions of the battery pack required for the protection level in the above step S3 and the execution of the corresponding monitoring protection mode include:

[0118] When the protection level is the non-system level protection, assigning work permissions to the remaining battery packs in the battery pack except the abnormal battery pack;

[0119] After the work authority allocation is completed and the work change of the remaining battery packs is completed, the work authority of the abnormal battery pack is removed.

[0120] It should be noted that if Figure 4 As shown in the figure, when the protection type corresponding to the self-protection state of the abnormal battery pack (such as over-temperature protection) only requires non-system-level protection, the main battery pack triggers the permission allocation operation after receiving the alarm of the abnormal battery pack, that is, the remaining battery packs in the battery pack except the abnormal battery pack are re-allocated with the work permissions, so that the remaining battery packs can perform corresponding operations (i.e., work changes) according to the latest assigned work permissions. The abnormal battery pack will not participate in this work permission allocation. It will turn off the charge and discharge switch after an alarm occurs and after a specified time (such as 5 seconds). During this period of time, if the main control removes the work permission of the abnormal battery pack, it will immediately turn off the charge and discharge switch.

[0121] In an optional embodiment, the control of the working permissions of the battery pack required for the protection level in the above step S3 and the execution of the corresponding monitoring protection mode include:

[0122] When the protection level is the non-system level protection and the battery pack is discharging, determining whether all the battery packs currently being discharged are the abnormal battery packs, and whether there are any waiting battery packs in the battery pack;

[0123] If all of them are abnormal battery packs and there are waiting battery packs, then all of the abnormal battery packs are replaced with the waiting battery packs;

[0124] Otherwise, remove the working permissions of all abnormal battery packs.

[0125] It should be noted that when the protection type corresponding to the self-protection state of the abnormal battery pack (such as over-temperature protection) only requires non-system-level protection, the main battery pack will execute the corresponding monitoring protection mode by controlling the working permissions of some battery packs (such as changing the working permissions of some battery packs in the battery pack). During the discharge process, when a battery pack discharges at a high temperature, the multi-battery pack parallel system (i.e., the main battery pack) will make the high-temperature battery pack quit working (remove the discharge working permission) and wait for the temperature to drop before joining the work again.

[0126] For example, if two battery packs in the battery pack are discharging (e.g. Figure 7 As shown in (a), when the BMS of a battery pack detects that the temperature is too high and triggers the over-temperature protection, since there are other normally functioning battery packs in the battery pack, the overall current of the multi-battery pack parallel system will not be cut off. The main battery pack will remove the working permissions of all abnormal battery packs, that is, turn off the charging switch and the discharging switch.

[0127] If only one battery pack in the battery pack is discharging (such as Figure 7 (b) shows that after the over-temperature protection is triggered, it will maintain output for a short time. During this time, the multi-battery pack parallel system (i.e., the main battery pack) will look for a battery pack to take over the discharge. If a battery pack to take over the discharge (the original waiting battery pack) can be found, the waiting battery pack will take over the discharge of the over-temperature protected battery pack to ensure that the system as a whole continues to flow. If there is no battery pack to take over, the system stops discharging and waits for the high-temperature battery pack to recover.

[0128] In an optional embodiment, the method further includes:

[0129] Step S4: determining the operating state of the battery pack based on all the state information; wherein the operating state includes: a working state and an idle state;

[0130] Step S5: When the battery pack is in the working state and the charge and discharge strategy is running, a charge and discharge protection mode is executed;

[0131] Step S6: When the battery pack is in the idle state, executing the sleep protection mode.

[0132] It should be noted that the main battery pack can not only monitor in real time whether there are abnormal battery packs in the battery pack and execute the corresponding monitoring protection mode, but also execute the charge and discharge protection mode when the battery pack runs the charge and discharge strategy to prevent large current hedging between battery packs. In addition, when the battery pack is in an idle state, the main battery pack will also execute the sleep protection mode, and conduct a comprehensive check on the status information of the system (battery pack) (such as the total bus current, the self-protection status of each battery pack, and external communication, etc.) to ensure that the battery pack enters sleep safely and stably, and avoid damage to the battery pack due to incorrect operation.

[0133] It is worth noting that there are 6 charging and discharging strategies in the embodiment of the present invention. The charging and discharging strategies adopted by the multi-battery pack parallel system can be switched at any time, such as switching through the system external APP or instrument UI; among them, there are 3 discharge strategies, namely, simultaneous discharge strategy, alternating discharge strategy, and mixed discharge (alternating + simultaneous) strategy, such as Figure 8 As shown:

[0134] (1) Simultaneous discharge strategy: By comparing the voltages of the battery packs, the battery pack with the highest voltage is used as the reference value, and all battery packs with voltage differences within a safe range are discharged together. This strategy can reduce the temperature rise of the battery pack and increase output performance;

[0135] (2) Rotating discharge strategy: By comparing the SOC values ​​of the battery packs, the battery pack with the highest (or lowest) SOC is discharged first. When one battery pack is empty, the next battery pack is discharged. This strategy can give priority to replacing the battery pack with a low SOC when replacing the battery.

[0136] (3) Hybrid discharge (alternating + simultaneous) strategy: First, each battery pack is discharged to a lower state of charge (SOC), and then all battery packs are discharged simultaneously. This strategy can take into account the advantages of the above two discharge strategies while ensuring the output performance of the terminal discharge.

[0137] There are also three charging strategies, namely, simultaneous charging strategy, alternating charging strategy, and mixed charging (alternating + simultaneous) strategy. Fig. 9 As shown:

[0138] (1) Simultaneous charging strategy: By comparing the voltages of the battery packs, the battery pack with the lowest voltage is used as the reference value, and all battery packs with voltage differences within a safe range are charged together. This discharge strategy can reduce the temperature rise of the battery pack and can also reduce the overall charging time by adjusting the charging current in real time when using a high-power smart charger.

[0139] (2) Alternate charging strategy: By comparing the SOC values ​​of the battery packs, the battery pack with the highest (or lowest) SOC is charged first. When one battery pack is fully charged, the next battery pack is charged. This strategy can concentrate the charging current on a single battery pack when using a low-power charger, allowing it to be fully charged quickly.

[0140] (3) Hybrid charging (alternating + simultaneous) strategy: First, charge each battery pack individually to a higher state of charge (SOC), and then charge all battery packs simultaneously, that is, first charge the battery packs in turn within the SOC range (20%-80%) where the battery packs charge the fastest, and then charge them simultaneously at the end of the charging process. This strategy can take into account the advantages of the above two charging strategies.

[0141] In an optional embodiment, in the above step S5, when the battery pack is in the working state and the charging and discharging strategy is executed, the charging and discharging protection mode is executed, including:

[0142] Obtaining a first working battery pack queue currently running on the battery pack; wherein the first working battery pack queue includes N battery packs; N≥1;

[0143] Based on the charging and discharging strategy, obtaining a second working battery pack queue to be operated;

[0144] Compare the first working battery pack queue and the second working battery pack queue to determine a battery pack set to be changed;

[0145] Change the working permissions of each battery pack in the changed battery pack set.

[0146] It should be noted that when the multi-battery pack parallel system is working, the main battery pack summarizes the status information of all battery packs in the battery group, and calculates the latest working battery pack queue (i.e. the second working battery pack queue to be operated) according to the current charge and discharge strategy mode, and compares it with the currently operating first working battery pack queue to obtain the changed battery pack set. There are four situations for changing the battery pack set:

[0147] The first case: only the newly added battery pack works;

[0148] The second situation: there are currently multiple working battery packs and some battery packs need to be removed;

[0149] The third situation: there are new battery packs added, removed, or maintained;

[0150] The fourth situation: complete replacement (the newly added battery pack completely replaces the currently working battery pack).

[0151] See also Fig.10, is a flow chart of an embodiment of a charge and discharge protection mode corresponding to the operation of the charge and discharge strategy provided by the present invention.

[0152] Specifically, the changing the working authority of each battery pack in the battery pack set includes:

[0153] In the implementation of the first case, when the changed battery pack set includes only at least one battery pack to be added, work authority is allocated to the battery pack to be added;

[0154] In the implementation of the second case, when the changed battery pack set includes only M1 battery packs to be removed, the work permissions of the battery packs to be removed are removed; wherein M1 <N;

[0155] In the implementation of the third situation, when the changed battery pack set includes at least one battery pack to be added and M2 battery packs to be removed, the work permissions of the battery pack to be removed are preferentially removed, and then the work permissions of the battery pack to be added are allocated; wherein, M2 <N;

[0156] In an implementation of the fourth situation, when the changed battery pack set includes at least one battery pack to be added and N battery packs to be removed, the charging switches of all the changed battery packs are turned off, and the discharging switch of at least one of the changed battery packs is turned on.

[0157] It should be noted that when a multi-battery pack parallel system is working, there will be a scenario where a high (low) voltage is switched to a low (high) voltage battery pack (corresponding to the fourth case of complete replacement mentioned above), especially in the alternating discharge or charging strategy. During the switching process, it is necessary to ensure that the system discharge does not interrupt the current, and at the same time, it does not cause a large current hedging between the high-voltage battery pack and the low-voltage battery pack, thereby triggering overcurrent protection. Therefore, during the switching process (replacement process), it is necessary to ensure that the charging MOS of the battery pack involved in the switching work is turned off at any time, and at least one of the discharge MOS is turned on. This can effectively avoid the interruption of the discharge current during the switching process and the triggering of overcurrent protection.

[0158] See also Fig.11 , is a flow chart of an embodiment of the present invention in which a battery pack to be removed is completely replaced.

[0159] In an optional embodiment, turning off the charging switches of all the changed battery packs and turning on the discharging switch of at least one of the changed battery packs includes:

[0160] Turn off the charging switch of the battery pack to be removed and maintain the corresponding discharging switch state;

[0161] respectively starting a first timer for the battery pack to be removed and a second timer for the battery pack to be added;

[0162] After the second timer starts, assigning work permissions to the battery pack to be added, turning on the discharge switch of the battery pack to be added, and prohibiting turning on the corresponding charging switch;

[0163] When the first timer exceeds a first preset time, removing the working permission of the battery pack to be removed;

[0164] When the second timer counts more than a second preset time, the charging switch restriction of the battery pack to be added is released; wherein the second preset time is greater than the first preset time.

[0165] like Fig.11 As shown, the successor is a battery pack that needs to exit the working state (battery pack to be removed), and the successor is a battery pack that needs to start the working state (battery pack to be added). During the succession process, the successor will start the timed removal permission mode, and the successor will also start the timed restriction charging MOS mode simultaneously. Among them, when the successor starts the timed removal permission mode, the working battery pack will turn off the charging MOS, while the discharging MOS will remain on, and after the first timer times out, its own working permission will be removed, and at this time both the charging and discharging MOS will be turned off; when the successor starts the timed restriction charging MOS mode, it will only turn on the discharging MOS when allocating the working permission of the battery pack to be added within the restricted time (the second preset duration), and the charging MOS will be in a closed state due to being restricted. After the second timer times out, the charging switch restriction will be cancelled; wherein, the timing time is set as the timed restriction charging MOS mode>timed removal permission mode>normal switching time, that is, the second preset duration>the first preset duration>normal switching time.

[0166] It is worth noting that since the multi-battery pack parallel system uses communication for control and management, if a sudden communication failure occurs during the switching process and the main control cannot control other battery packs, the above timing mechanism can avoid long-term discharge through the body diode in the charging MOS, thereby protecting the MOS from being burned.

[0167] To better describe the complete takeover switching process, a specific implementation example is provided below for reference:

[0168] like Fig.12As shown in the figure, in a multi-battery pack parallel system, there is a battery pack to be removed (the successor) and a battery pack to be added (the successor) in the battery pack. The successor sets the timed removal permission mode, that is, the discharge MOS is turned on, the charging MOS is turned off, and the discharge current passes through the body diode of the charging MOS; at the same time, the successor sets the timed restricted charging MOS mode. When the successor is assigned permissions, the discharge MOS is turned on, and the charging MOS is closed due to restrictions, and the discharge current passes through the body diode of the charging MOS. After the successor times out or is controlled by the main battery pack, the working permission is removed, and both the charging and discharging MOS are turned off; then, the successor times out and cancels the restriction on the charging MOS.

[0169] In an optional embodiment, in the above step S6, when the battery pack is in the idle state, executing the sleep protection mode includes:

[0170] After notifying all the slave battery packs to enter sleep mode through internal communication, controlling the master battery pack to enter sleep mode; or

[0171] A battery pack is designated from the battery packs participating in the discharge operation to maintain the discharge operation, and the remaining battery packs in the battery group are controlled to enter dormancy.

[0172] It should be noted that a single battery pack enters sleep mode when it is in a long-term idle state (no charging or discharging, external communication, key operation, no protection, etc.). When multiple battery packs are connected in parallel, there will be mutual charging current and internal communication between the battery packs, making it impossible for the original battery pack to enter sleep mode by itself.

[0173] The embodiment of the present invention uses the main battery pack to check whether the multi-battery pack parallel system is in an idle state, that is, to determine whether the battery pack meets the sleep condition; wherein the sleep condition is that the total bus current is less than the preset current threshold, no battery pack is in a self-protection state, and there is no communication request from the outside. If the above sleep conditions are met, the main control battery pack can determine that the multi-battery pack parallel system is in an idle state and allow the battery pack to enter sleep. The embodiment of the present invention specifically has the following two ways to put the battery pack into sleep:

[0174] (1) If the system does not need to start discharging in the sleep state, the master battery pack will make all the slave battery packs enter sleep mode through communication, and finally control itself to enter sleep mode;

[0175] (2) If the system needs to start discharging in the sleep state (such as continuing to power a low-power device or the system needs to wake up when a large current flows), before the sleep operation, select one of the battery packs that are turned on for discharging to maintain the discharge function (the main battery pack (main control) is selected first, followed by the battery pack with high power), and the other battery packs are shut down to prevent mutual charging during sleep. After the main battery pack (main control) notifies the slave battery pack to enter sleep, the main battery pack itself enters sleep, such as Fig.13 It is worth noting that the battery with the discharge function turned on will also enter a dormant state. When there is current, it will wake itself up and then wake up other battery packs through communication.

[0176] See also Fig.14 , is a structural schematic diagram of a parallel battery pack protection device provided by the present invention.

[0177] A second aspect of the present invention provides a parallel battery pack protection device, which is used to implement the parallel battery pack protection method described in any embodiment of the first aspect, and the device includes:

[0178] The information acquisition module 11 is used to obtain the status information of all battery packs in the battery pack and determine the abnormal battery pack; wherein the abnormal battery pack is in a self-protection state; the battery pack includes: the master battery pack and a plurality of slave battery packs;

[0179] A protection level determination module 12, configured to determine an enabled protection level based on the protection type of the self-protection state; wherein the protection level includes: system-level protection and non-system-level protection;

[0180] The monitoring and protection execution module 13 is used to control the working authority of the battery pack required by the protection level and execute the corresponding monitoring and protection mode; wherein the working authority includes: charging working authority and discharging working authority.

[0181] Optionally, the monitoring protection execution module 13 includes:

[0182] A first removing unit, configured to remove working permissions of all the battery packs when the protection level is the system-level protection;

[0183] The first allocation unit is used to reallocate the working rights of each battery pack in the battery group according to the current charge and discharge strategy after the system-level protection is released.

[0184] Optionally, the monitoring protection execution module 13 includes:

[0185] A second allocation unit, configured to allocate work permissions to the remaining battery packs in the battery pack except the abnormal battery pack when the protection level is the non-system level protection;

[0186] The second removing unit is used to remove the working authority of the abnormal battery pack after the working authority allocation is completed and the working change of the remaining battery packs is completed.

[0187] Optionally, the monitoring protection execution module 13 includes:

[0188] a second judgment unit, configured to judge whether all the battery packs currently being discharged are the abnormal battery packs, and whether there are any waiting battery packs in the battery pack when the protection level is the non-system level protection and the battery pack is being discharged;

[0189] A first replacement unit, configured to replace all the abnormal battery packs with the waiting battery packs if all of them are abnormal battery packs and there are waiting battery packs;

[0190] The fourth removing unit is used to remove the working authority of all the abnormal battery packs otherwise.

[0191] Optionally, the method further comprises:

[0192] An operating state acquisition module, used to determine the operating state of the battery pack based on all the state information; wherein the operating state includes: a working state and an idle state;

[0193] A charge and discharge protection mode execution module, used for executing a charge and discharge protection mode when the battery pack is in the working state and the charge and discharge strategy is running;

[0194] The sleep protection mode execution module is used to execute the sleep protection mode when the battery pack is in the idle state.

[0195] Optionally, the charge and discharge protection mode execution module includes:

[0196] A first queue acquisition unit is used to acquire a first working battery pack queue currently running on the battery pack; wherein the first working battery pack queue includes N battery packs; N≥1;

[0197] A second queue acquisition unit, used for acquiring a second working battery pack queue to be operated based on the charging and discharging strategy;

[0198] A comparison unit, configured to compare the first working battery pack queue with the second working battery pack queue to determine a changed battery pack set;

[0199] The authority changing unit is used to change the working authority of each battery pack in the changed battery pack set.

[0200] Optionally, the permission changing unit includes:

[0201] A first permission changing subunit is used for allocating work permissions to the battery pack to be added when the changed battery pack set only includes at least one battery pack to be added;

[0202] The second permission changing subunit is used to remove the working permission of the battery pack to be removed when the changed battery pack set only includes M1 battery packs to be removed; wherein M1 <N;

[0203] The third permission changing subunit is used to assign working permissions to the battery packs to be added after preferentially removing the working permissions of the battery packs to be removed when the changed battery pack set includes at least one battery pack to be added and M2 battery packs to be removed; wherein M2 <N;

[0204] The fourth permission changing subunit is used to turn off the charging switches of all changed battery packs and turn on the discharging switch of at least one changed battery pack when the changed battery pack set includes at least one battery pack to be added and N battery packs to be removed.

[0205] Optionally, the step of turning off charging switches of all changed battery packs and turning on at least one discharging switch of the changed battery pack in the fourth permission changing subunit includes:

[0206] Turn off the charging switch of the battery pack to be removed and maintain the corresponding discharging switch state;

[0207] respectively starting a first timer for the battery pack to be removed and a second timer for the battery pack to be added;

[0208] After the second timer starts, assigning work permissions to the battery pack to be added, turning on the discharge switch of the battery pack to be added, and prohibiting turning on the corresponding charging switch;

[0209] When the first timer exceeds a first preset time, removing the working permission of the battery pack to be removed;

[0210] When the second timer counts more than a second preset time, the charging switch restriction of the battery pack to be added is released; wherein the second preset time is greater than the first preset time.

[0211] Optionally, the sleep protection mode execution module includes:

[0212] a sleep unit, configured to control the master battery pack to enter sleep mode after notifying all the slave battery packs to enter sleep mode through internal communication; or

[0213] A battery pack is designated from the battery packs participating in the discharge operation to maintain the discharge operation, and the remaining battery packs in the battery group are controlled to enter dormancy.

[0214] It should be noted that the parallel battery pack protection device provided in the second aspect of the present invention can implement all processes of the parallel battery pack protection method described in the first aspect of the present invention. The functions of each module in the device and the technical effects achieved are respectively the same as the functions and technical effects achieved by the parallel battery pack protection method described in the first aspect of the present invention, and will not be repeated here.

[0215] An embodiment of the third aspect of the present invention provides a computer-readable storage medium, which includes a stored computer program; wherein, when the computer program is running, it controls the device where the computer-readable storage medium is located to execute the parallel battery pack protection method described in any embodiment of the first aspect above.

[0216] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for protecting a parallel battery pack, characterized in that: The method is performed by a main battery pack and includes: Acquire status information of all battery packs in the battery pack, and determine abnormal battery packs; wherein the abnormal battery packs are in a self-protection state; the battery pack includes: the master battery pack and a plurality of slave battery packs; Determine the enabled protection level based on the protection type of the self-protection state; wherein the protection level includes: system-level protection and non-system-level protection; Control the working permissions of the battery pack required for the protection level and execute the corresponding monitoring protection mode; wherein the working permissions include: charging working permissions and discharging working permissions.

2. The parallel battery pack protection method according to claim 1, characterized in that: The control of the protection level required by the battery pack's working permissions and the execution of the corresponding monitoring protection mode include: When the protection level is the system-level protection, removing the working permissions of all the battery packs; After the system-level protection is released, the working authority of each battery pack in the battery group is reallocated according to the current charge and discharge strategy.

3. The parallel battery pack protection method according to claim 1, characterized in that: The control of the protection level required by the battery pack's working permissions and the execution of the corresponding monitoring protection mode include: When the protection level is the non-system level protection, assigning work permissions to the remaining battery packs in the battery pack except the abnormal battery pack; After the work authority allocation is completed and the work change of the remaining battery packs is completed, the work authority of the abnormal battery pack is removed.

4. The parallel battery pack protection method according to claim 1, characterized in that: The control of the protection level required by the battery pack's working permissions and the execution of the corresponding monitoring protection mode include: When the protection level is the non-system level protection and the battery pack is discharging, determining whether all the battery packs currently being discharged are the abnormal battery packs, and whether there are any waiting battery packs in the battery pack; If all of them are abnormal battery packs and there are waiting battery packs, then all of the abnormal battery packs are replaced with the waiting battery packs; Otherwise, remove the working permissions of all abnormal battery packs.

5. The parallel battery pack protection method according to claim 1, characterized in that: The method further comprises: Based on all the state information, determining the operating state of the battery pack; wherein the operating state includes: a working state and an idle state; When the battery pack is in the working state and the charging and discharging strategy is running, a charging and discharging protection mode is executed; When the battery pack is in the idle state, a sleep protection mode is executed.

6. The parallel battery pack protection method according to claim 5, characterized in that: When the battery pack is in the working state and the charge and discharge strategy is executed, the charge and discharge protection mode is executed, including: Obtaining a first working battery pack queue currently running on the battery pack; wherein the first working battery pack queue includes N battery packs; N≥1; Based on the charging and discharging strategy, obtaining a second working battery pack queue to be operated; Compare the first working battery pack queue and the second working battery pack queue to determine a battery pack set to be changed; Change the working permissions of each battery pack in the changed battery pack set.

7. The parallel battery pack protection method according to claim 6, characterized in that: The changing the working permissions of each battery pack in the battery pack set includes: When the changed battery pack set includes only at least one battery pack to be added, assigning work permissions to the battery pack to be added; When the changed battery pack set contains only M1 battery packs to be removed, the working permissions of the battery packs to be removed are removed; wherein M1 <N; When the changed battery pack set includes at least one battery pack to be added and M2 battery packs to be removed, the work permissions of the battery pack to be removed are preferentially removed, and then the work permissions of the battery pack to be added are allocated; wherein M2 <N; When the changed battery pack set includes at least one battery pack to be added and N battery packs to be removed, the charging switches of all the changed battery packs are turned off, and the discharging switch of at least one of the changed battery packs is turned on.

8. The parallel battery pack protection method according to claim 7, characterized in that: The step of turning off the charging switches of all the changed battery packs and turning on the discharging switch of at least one of the changed battery packs comprises: Turn off the charging switch of the battery pack to be removed and maintain the corresponding discharging switch state; respectively starting a first timer for the battery pack to be removed and a second timer for the battery pack to be added; After the second timer starts, assigning work permissions to the battery pack to be added, turning on the discharge switch of the battery pack to be added, and prohibiting turning on the corresponding charging switch; When the first timer exceeds a first preset time, removing the working permission of the battery pack to be removed; When the second timer counts more than a second preset time, the charging switch restriction of the battery pack to be added is released; wherein the second preset time is greater than the first preset time.

9. The parallel battery pack protection method according to claim 5, characterized in that: When the battery pack is in the idle state, executing the sleep protection mode includes: After notifying all the slave battery packs to enter sleep mode through internal communication, controlling the master battery pack to enter sleep mode; or A battery pack is designated from the battery packs participating in the discharge operation to maintain the discharge operation, and the remaining battery packs in the battery group are controlled to enter dormancy.

10. A parallel battery pack protection device, characterized in that: include: An information acquisition module, used to acquire status information of all battery packs in the battery pack and determine abnormal battery packs; wherein the abnormal battery packs are in a self-protection state; the battery pack includes: the master battery pack and a plurality of slave battery packs; A protection level determination module, configured to determine an enabled protection level based on the protection type of the self-protection state; wherein the protection level includes: system-level protection and non-system-level protection; The monitoring and protection execution module is used to control the working permissions of the battery pack required by the protection level and execute the corresponding monitoring and protection mode; wherein the working permissions include: charging working permissions and discharging working permissions.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program; wherein, when the computer program is run, it controls the device where the computer-readable storage medium is located to execute the parallel battery pack protection method according to any one of claims 1 to 9.

Images