Battery system and forced charging and discharging method thereof

Abstract

The invention discloses a battery system and a forced charging and discharging method thereof, and belongs to the technical field of batteries. The method is executed by a control assembly. The method comprises the steps that when a forced control instruction issued by an energy storage converter is received and the alarm level of a voltage fault in a battery assembly is within a preset alarm level range, fault protection operation corresponding to the voltage fault within the preset alarm level range is closed, and forced charging and discharging operation is started; the fault protection operation corresponding to the voltage fault in the preset alarm grade range comprises the following steps: controlling the switch assembly to be switched off; the forced charging and discharging operation comprises the steps that the switch assembly is controlled to be switched on, so that the energy storage converter can execute preset actions on the battery assembly through the total positive end and the total negative end. According to the embodiment of the invention, on the basis of ensuring the reliability of the battery system, the forced charging and discharging efficiency of the battery system is improved, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery system and a forced charging and discharging method thereof. Background Art

[0002] At present, for a battery system composed of at least one battery pack, overcharge / over-discharge of the battery pack is inevitable during its actual use or testing. In common protection strategies, in order to protect the system, the charge and discharge circuit of the battery system is usually cut off when the alarm protection is triggered. At this time, if the battery system needs to be charged and discharged, the original charge and discharge circuit cannot be used, and the battery pack needs to be disassembled and each battery pack needs to be charged and discharged with the help of an external charger or load. However, the charge and discharge efficiency of charging and discharging after disassembling the battery pack is low, the cost is high, and it affects the reliability of the system. Summary of the invention

[0003] The present invention provides a battery system and a forced charging and discharging method thereof, so as to improve the efficiency of forced charging and discharging of the battery system and reduce the cost while ensuring the reliability of the battery system.

[0004] In a first aspect, an embodiment of the present invention provides a forced charging and discharging method for a battery system, the battery system comprising: a battery assembly, a switch assembly, a control assembly and an energy storage converter; the battery assembly and the switch assembly are connected in series between a total positive terminal and a total negative terminal of the battery system, the control assembly is respectively connected to the battery assembly, the switch assembly and the energy storage converter; the energy storage converter is also respectively connected to the total positive terminal and the total negative terminal; the forced charging and discharging method for the battery system is executed by the control assembly; the forced charging and discharging method for the battery system comprises:

[0005] When receiving the forced control instruction sent by the energy storage converter, and the alarm level of the voltage fault in the battery assembly is within the preset alarm level range, the fault protection operation corresponding to the voltage fault within the preset alarm level range is turned off, and the forced charge and discharge operation is turned on; wherein the fault protection operation corresponding to the voltage fault within the preset alarm level range includes: controlling the switch assembly to be disconnected; the forced charge and discharge operation includes: controlling the switch assembly to be turned on, so that the energy storage converter can perform a preset action on the battery assembly through the total positive terminal and the total negative terminal;

[0006] Among them, when the forced control instruction is a forced charging instruction, the voltage fault is an undervoltage fault, and the preset action is charging; when the forced control instruction is a forced discharging instruction, the voltage fault is an overvoltage fault, and the preset action is discharging.

[0007] Optionally, after turning off the fault protection operation corresponding to the voltage fault within the preset alarm level range and turning on the forced charge and discharge operation, the method further includes:

[0008] Counting the action duration corresponding to the preset action;

[0009] When the duration of the action exceeds the preset duration, judging whether the preset action actually occurs according to the electrical parameters of the battery assembly;

[0010] When the action duration does not exceed the preset duration, continuing to perform the forced charge and discharge operation;

[0011] Wherein, if the preset action has actually occurred, the forced charging and discharging method of the battery system further includes: starting a fault protection operation corresponding to a voltage fault within the preset alarm level range, and waiting to receive a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter;

[0012] If the preset action does not actually occur, the forced charging and discharging method of the battery system further includes: starting a fault protection operation corresponding to a voltage fault within the preset alarm level range, and waiting to receive a next forced control instruction issued by the energy storage converter.

[0013] Optionally, the battery assembly includes a plurality of cells connected in series between a positive electrode and a negative electrode of the battery assembly, and the electrical parameters of the battery assembly include: a maximum voltage among the single cell voltages of each of the cells, and an operating current flowing through the battery assembly;

[0014] Determining whether the preset action actually occurs according to the electrical parameters of the battery assembly includes:

[0015] When the maximum voltage satisfies a preset voltage condition, and / or the action current satisfies a preset current condition, it is determined that the preset action has actually occurred;

[0016] When the maximum voltage does not satisfy the preset voltage condition, and the action current does not satisfy the preset current condition, it is determined that the preset action does not actually occur.

[0017] Optionally, when the forced control instruction is a forced charging instruction, the maximum voltage is the lowest voltage among the single cell voltages of the battery cells, and the action current is the charging current; the voltage preset condition is: the lowest voltage is greater than a first voltage threshold; the current preset condition is: the charging current is greater than a first current value and the duration of the charging current is greater than a first preset time;

[0018] When the forced control instruction is a forced discharge instruction, the maximum voltage is the highest voltage among the single cell voltages of each of the battery cells, and the action current is the discharge current; the voltage preset condition is: the highest voltage is less than the second voltage threshold; the current preset condition is: the discharge current is greater than the second current value and the duration of the discharge current is greater than the second preset time; wherein, the second voltage threshold is greater than the first voltage threshold.

[0019] Optionally, before starting the forced charge and discharge operation, the method further includes:

[0020] Determining whether a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter is received;

[0021] If yes, stop the forced charge and discharge operation, and start the fault protection operation corresponding to the voltage fault within the preset alarm level range;

[0022] If not, start the forced charge and discharge operation, and count the action duration corresponding to the preset action;

[0023] Correspondingly, when the action duration does not exceed the preset duration, the process returns to the step of determining whether a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter is received.

[0024] Optionally, the battery assembly includes a plurality of battery cells connected in series between a positive electrode and a negative electrode of the battery assembly;

[0025] The undervoltage fault includes: a single cell undervoltage fault and a battery assembly total voltage undervoltage fault;

[0026] The overvoltage fault includes: battery cell single voltage fault and battery assembly total voltage overvoltage fault;

[0027] and / or,

[0028] The alarm level of the voltage fault in the battery assembly includes at least three alarm levels; wherein the number of the alarm levels is positively correlated with the severity of the voltage fault;

[0029] The preset alarm level range includes: other alarm levels except the first and last alarm levels.

[0030] In a second aspect, an embodiment of the present invention further provides a forced charging and discharging method for a battery system, the battery system comprising: a battery assembly, a switch assembly, a control assembly and an energy storage converter; the battery assembly and the switch assembly are connected in series between the total positive terminal and the total negative terminal of the battery system, the control assembly is respectively connected to the battery assembly, the switch assembly and the energy storage converter; the energy storage converter is also respectively connected to the total positive terminal and the total negative terminal; the forced charging and discharging method for the battery system is executed by the energy storage converter; the forced charging and discharging method for the battery system comprises:

[0031] When the operation information of the battery assembly uploaded by the control component meets the forced charge and discharge conditions, a forced control instruction is issued to the control component, and a preset action is performed on the battery assembly through the total positive terminal and the total negative terminal;

[0032] Among them, when the forced charge and discharge condition is a forced charge condition, the forced control instruction is a forced charge instruction, and the preset action is charging; when the forced charge and discharge condition is a forced discharge condition, the forced control instruction is a forced discharge instruction, and the preset action is discharging.

[0033] Optionally, after issuing a forced control instruction to the control component and performing a preset action on the battery component through the total positive terminal and the total negative terminal, the method further includes:

[0034] When the operation information of the battery assembly uploaded by the control component meets the forced control stop condition corresponding to the preset action currently being executed, a forced control end instruction is sent to the control component, and the preset action is stopped;

[0035] Among them, when the currently executed preset action is charging, the forced control stop condition is the forced charging end condition, and the forced control end instruction is the forced charging end instruction; when the currently executed preset action is discharging, the forced charging and discharging stop condition is the forced discharging end condition, and the forced control end instruction is the forced discharging end instruction.

[0036] Optionally, the energy storage converter is also connected to a power grid;

[0037] When the preset action is charging, the energy storage inverter uses the power grid as the power source of the battery assembly; when the preset action is discharging, the energy storage inverter uses the power grid as the load of the battery assembly.

[0038] In a third aspect, an embodiment of the present invention further provides a battery system, comprising: a battery assembly, a switch assembly, a control assembly and an energy storage converter; the battery assembly and the switch assembly are connected in series between a total positive terminal and a total negative terminal of the battery system, the control assembly is respectively connected to the battery assembly, the switch assembly and the energy storage converter; the energy storage converter is also respectively connected to the total positive terminal and the total negative terminal;

[0039] The control component is used to execute the forced charging and discharging method of the battery system provided by any embodiment of the present invention; the energy storage inverter is used to execute the forced charging and discharging method of the battery system provided by any embodiment of the present invention.

[0040] In the forced charging and discharging method of the battery system provided by the embodiment of the present invention, the control component determines whether to start the forced charging and discharging operation based on the received forced control instruction and the actual voltage fault alarm level, which is equivalent to preliminarily identifying the correctness of the forced control instruction, and can avoid misoperation to a certain extent. In addition, when forced charging and discharging is required, there is no need to disassemble the battery component and connect an external charger or load, but to force the control switch component to conduct, and use the original charging and discharging circuit of the battery system for charging and discharging. In this way, firstly, forced charging and discharging can be achieved based on the original hardware conditions, without adjusting the wiring, saving manpower and time, improving charging and discharging efficiency, and reducing disassembly and assembly losses and risks; secondly, the original charging and discharging circuit is used to directly force the entire battery component to charge and discharge, without disassembling it into multiple blocks and then charging and discharging separately, which can avoid the problem of unbalanced charging and discharging and ensure system reliability and safety; thirdly, there is no need to purchase / independently develop the equipment required for forced charging and discharging, which can effectively reduce costs, and the code modification is flexible, the portability is strong, and the existing functional modules of the control component are not destroyed, and other fault detection and protection functions of the system are not affected. In summary, the embodiments of the present invention can improve the efficiency of forced charging and discharging of the battery system and reduce the cost while ensuring the reliability of the battery system.

[0041] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 is a structural schematic diagram of a battery system provided by an embodiment of the present invention;

[0044] Figure 2 is a schematic flow chart of a forced charging and discharging method for a battery system provided by an embodiment of the present invention;

[0045] Figure 3 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention;

[0046] Figure 4 This is a flowchart of determining whether a preset action actually occurs, provided by an embodiment of the present invention;

[0047] Figure 5 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention;

[0048] Figure 6 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention;

[0049] Figure 7 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention;

[0050] Figure 8 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention;

[0051] Fig. 9 It is a structural schematic diagram of another battery system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 field without creative work should fall within the scope of protection of the present invention.

[0053] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0054] As mentioned in the background technology, currently after the protection is triggered to cut off the charging and discharging circuit of the battery system, the battery pack needs to be disassembled before charging and discharging. The main disadvantages of this solution include:

[0055] 1. The actual operation process is time-consuming and labor-intensive. In large cabinets, multiple battery packs are often connected in series, and a large number of circuit boards and battery packs need to be disassembled. The reinstallation process may also involve rewiring, which will increase the risk of the system and affect the system reliability.

[0056] 2. Increase the purchase cost / development cost. Whether purchasing or independently developing a charger requires time and money costs. At the same time, newly purchased external equipment also brings problems such as maintenance and after-sales.

[0057] 3. The charging efficiency of the external charger is low, especially for cabinets with multiple battery packs. When the system as a whole is undervoltage or overvoltage, a large number of battery packs need to be charged and discharged, and the disassembly and charging and discharging process is cumbersome. In addition, if charging and discharging are not performed with the help of the system platform, charging voltage imbalance is prone to occur, affecting system reliability and life.

[0058] 4. Large-scale battery overvoltage and undervoltage is not a common phenomenon. This situation mostly occurs when the battery pack is left for a long time or used improperly. Purchasing related charging and discharging equipment or investing in development plans for this purpose alone will result in a waste of resources.

[0059] In summary, in the related art, the charging and discharging efficiency of disassembling the battery pack for charging and discharging is low, the cost is high, and the system reliability is affected.

[0060] To solve the above problems, an embodiment of the present invention provides a forced charging and discharging method for a battery system, which utilizes the original charging and discharging circuit of the battery system to perform forced charging and discharging after undervoltage / overvoltage, thereby improving the efficiency of forced charging and discharging of the battery system and reducing costs while ensuring the reliability of the battery system. To facilitate the explanation of the method, the basic structure of the battery system is briefly described below.

[0061] Figure 1 is a schematic diagram of the structure of a battery system provided by an embodiment of the present invention. Figure 1 , exemplarily, the battery system may include: a battery assembly 10, a switch assembly 20, a control assembly 30 and a power conversion system (PCS) 40. The battery assembly 10 and the switch assembly 20 are connected in series between the total positive terminal P1 and the total negative terminal P2 of the battery system, and the control assembly 30 is respectively connected to the battery assembly 10, the switch assembly 20 and the power conversion system 40; the power conversion system 40 is also respectively connected to the total positive terminal P1 and the total negative terminal P2.

[0062] Specifically, the battery assembly 10 may include a plurality of battery packs connected in series between the positive electrode BAT1 and the negative electrode BAT2 of the battery assembly 10, and each battery pack may include a plurality of battery cells connected in series. The switch assembly 20 may include: a first switch unit 210 connected between the positive electrode BAT1 of the battery assembly 10 and the total positive terminal P1, and a second switch unit 220 connected between the negative electrode BAT2 of the battery assembly 10 and the total negative terminal P2. The first switch unit 210, the battery assembly 10, and the second switch unit 220 are sequentially connected in series between the total positive terminal P1 and the total negative terminal P2 to form a charge and discharge circuit (or a high-voltage circuit) of the battery assembly 10, and the on and off of the switch assembly 20 determines the on and off of the charge and discharge circuit. In the switch assembly 20, when at least one switch unit is disconnected, the switch assembly 20 is disconnected; when both switch units are turned on, the switch assembly 20 is turned on. Exemplarily, the first switch unit 210 and the second switch unit 220 can be turned on or off synchronously.

[0063] As a control component, the control component 30 can collect the operating parameters of the battery assembly 10 in real time, such as collecting the current, voltage and temperature of each battery cell, and collecting the total voltage and electrode temperature of the battery assembly 10, and can control the operating state of the battery assembly 10, such as performing charge balancing and discharge balancing. The control part of the energy storage inverter 40 can be connected to the control component 30, and exchange data with the control component 30, such as receiving the operating information uploaded by the control component 30, and sending control instructions to the control component 30; the energy conversion part of the energy storage inverter 40 can be connected to the total positive terminal P1 and the total negative terminal P2, and connected to the power grid; the control part of the energy storage inverter 40 can control the working state of its energy conversion part; when the switch component 20 is turned on, based on the control of the energy storage inverter 40, the power grid can be used as a power source to charge the battery assembly 10, or the power grid can be used as a load to discharge the battery assembly 10 to the power grid.

[0064] The following describes the implementation of the forced charging and discharging method of the battery system from the perspectives of the control component 30 and the energy storage converter 40 .

[0065] An embodiment of the present invention provides a forced charging and discharging method for a battery system, which is executed by a control component. The forced charging and discharging method for the battery system includes: when a forced control instruction issued by an energy storage inverter is received and the alarm level of a voltage fault in the battery component is within a preset alarm level range, closing the fault protection operation corresponding to the voltage fault within the preset alarm level range, and starting the forced charging and discharging operation.

[0066] Among them, the fault protection operation corresponding to the voltage fault within the preset alarm level range includes: controlling the switch component to be disconnected. The forced charge and discharge operation includes: controlling the switch component to be turned on so that the energy storage converter can perform the preset action on the battery component through the total positive terminal and the total negative terminal. When the forced control instruction is a forced charging instruction, the voltage fault is an undervoltage fault, and the preset action is charging; when the forced control instruction is a forced discharging instruction, the voltage fault is an overvoltage fault, and the preset action is discharging.

[0067] Specifically, voltage stability / balance is an important indicator for the battery system to maintain safe operation. When a voltage fault occurs in a battery component, excessive or low voltage will cause the internal pressure of the battery component to increase, affecting the charging and discharging efficiency of the battery component, accelerating the aging process of the battery component, shortening the service life of the battery component, and easily leading to safety problems such as short circuit, leakage and thermal runaway. Therefore, during the operation of the battery system, the control component will detect the voltage condition and SOC (State Of Charge) and other operating information of the battery component in real time, and upload it to the energy storage inverter in real time. It is understandable that the operation process of the system can be in actual use and during testing, and the specific scenario is not limited here.

[0068] Usually, in the control component, multi-level alarm protection is provided according to the severity of the voltage fault, a series of alarm levels are set, and the corresponding fault protection operations under each alarm level are specified. Among them, the fault protection operation corresponding to the voltage fault under at least some alarm levels includes disconnecting the switch component. Exemplarily, when the severity of the fault is low, such as slight overvoltage / undervoltage, the fault protection operation may be only an alarm without disconnecting the switch component, such as an alarm in the form of sound, light, vibration, etc. to remind relevant personnel to pay attention to the voltage situation; when the fault is more serious, that is, the actual voltage caused by overvoltage / undervoltage deviates from the voltage allowable range by a large amount, the fault protection operation may be to disconnect the switch component while the alarm is issued, and stop the charging and discharging of the battery component to avoid further expansion of the fault. Then, the preset alarm level range includes: at least some voltage fault alarm levels including the operation of disconnecting the switch component in the fault protection operation; disconnecting the switch component may be to disconnect at least one of the first switch unit and the second switch unit. It is understandable that the first switch unit and the second switch unit may include one or more of a relay, a circuit breaker and a contactor; at different alarm levels of voltage fault, the specific operation of disconnecting the switch assembly may be different, such as different types of disconnected switch devices and / or different disconnection sequences of switch devices, which are not specifically limited here. The control assembly may store the judgment conditions of voltage faults at various levels and the corresponding fault protection operations. The control assembly may determine whether a voltage fault occurs in the battery assembly according to the voltage condition of the battery assembly, and determine the alarm level of the voltage fault when a voltage fault occurs.

[0069] The energy storage converter determines whether the battery assembly needs to be forced to charge and discharge based on the operating information of the battery assembly; and sends a forced control instruction to the control assembly when forced charging and discharging is required. For example, when the total voltage / cell voltage / SOC of the battery assembly is lower than the corresponding preset limit, a forced charging instruction is issued; when the total voltage / cell voltage / SOC of the battery assembly is higher than the corresponding preset limit, a forced discharging instruction is issued.

[0070] See also Figure 2 The forced charging and discharging method of the battery system may specifically include the following steps:

[0071] S110, determining whether a mandatory control instruction issued by the energy storage converter is received; if so, executing S120, if not, terminating this control.

[0072] Among them, when the energy storage converter does not issue a forced control instruction, the control component can perform corresponding fault protection operations according to the voltage fault alarm level determined by monitoring, for example, when the alarm level of the voltage fault is within the preset alarm level range, the control switch component is disconnected.

[0073] It is understandable that the "end" in each of the drawings of the embodiments of the present invention refers to the end of this forced charge and discharge control process. Since the control component monitors the operating information of the battery component in real time and uploads it to the energy storage inverter, the energy storage inverter also determines in real time whether forced charge and discharge are required. Therefore, after each forced charge and discharge control process ends, the next forced charge and discharge control process can be entered. The execution frequency of the forced charge and discharge control process can be set according to actual needs and is not limited here.

[0074] S120, determining whether the alarm level of the voltage fault in the battery assembly is within a preset alarm level range; if so, executing S130; if not, terminating this control.

[0075] Among them, when the energy storage converter has issued a forced control instruction, the judgment of step S120 is equivalent to further determining whether there is indeed a need for forced charging / discharging according to the actual voltage of the battery assembly. When the energy storage converter issues a forced control instruction and the alarm level of the corresponding voltage fault in the battery assembly is within the preset alarm level range, the operation corresponding to forced charging and discharging is performed, which can effectively avoid misoperation.

[0076] S130: Turn off the fault protection operation corresponding to the voltage fault within the preset alarm level range, and turn on the forced charge and discharge operation.

[0077] Specifically, turning off the fault protection operation corresponding to the voltage fault within the preset alarm level range is equivalent to shielding all the fault protection operations corresponding to the voltage faults of each alarm level within the preset alarm level range, thereby preventing the control component from disconnecting the switch component in response to the fault protection operation requirement during the forced charging / discharging process. Then, turning on the forced charging / discharging operation is equivalent to forcibly controlling the switch component to turn on, and using the energy storage inverter to force the battery component to charge / discharge using the original charging and discharging circuit in the battery system. Specifically, the battery component needs to be forced to charge under an undervoltage fault, and the battery component needs to be forced to discharge under an overvoltage fault.

[0078] In the forced charging and discharging method of the battery system provided by the embodiment of the present invention, the control component determines whether to start the forced charging and discharging operation based on the received forced control instruction and the actual voltage fault alarm level, which is equivalent to preliminarily identifying the correctness of the forced control instruction, and can avoid misoperation to a certain extent. In addition, when forced charging and discharging is required, there is no need to disassemble the battery component and connect an external charger or load, but to force the control switch component to conduct, and use the original charging and discharging circuit of the battery system for charging and discharging. In this way, firstly, forced charging and discharging can be achieved based on the original hardware conditions, without adjusting the wiring, saving manpower and time, improving charging and discharging efficiency, and reducing disassembly and assembly losses and risks; secondly, the original charging and discharging circuit is used to directly force the entire battery component to charge and discharge, without disassembling it into multiple blocks and then charging and discharging separately, which can avoid the problem of unbalanced charging and discharging and ensure system reliability and safety; thirdly, there is no need to purchase / independently develop the equipment required for forced charging and discharging, which can effectively reduce costs, and the code modification is flexible, the portability is strong, and the existing functional modules of the control component are not destroyed, and other fault detection and protection functions of the system are not affected. In summary, the embodiments of the present invention can improve the efficiency of forced charging and discharging of the battery system and reduce the cost while ensuring the reliability of the battery system.

[0079] On the basis of the above embodiments, optionally, the battery assembly includes a plurality of battery cells connected in series between the positive electrode and the negative electrode of the battery assembly, and the plurality of battery cells may belong to one or more battery packs. Specifically, the undervoltage fault in the voltage fault may include: a single battery cell undervoltage fault and a battery assembly total voltage undervoltage fault. The overvoltage fault in the voltage fault may include: a single battery cell overvoltage fault and a battery assembly total voltage overvoltage fault.

[0080] Among them, the cell voltage is the voltage at both ends of a single cell. If the cell voltage is too high or too low, the voltage difference between the cells in the battery pack will be too large, affecting the charging and discharging efficiency of the battery pack, resulting in insufficient charging or incomplete discharging, thereby affecting the battery pack's endurance. The total voltage of the battery assembly is the voltage between the positive and negative poles of the battery assembly; total voltage overvoltage can easily lead to problems such as overheating and electrolyte rupture inside the battery assembly, and total voltage undervoltage can easily lead to a significant reduction in battery capacity, affecting the normal operation of the system. Therefore, whether it is an undervoltage or overvoltage fault, the cell voltage and the total voltage of the battery assembly are taken into account. As long as the alarm level of one of the faults is within the corresponding preset alarm level range, it is considered that there is a need for charging / discharging.

[0081] On the basis of the above embodiments, optionally, the alarm level of the voltage fault in the battery assembly includes at least three alarm levels. Among them, the number of alarm levels is positively correlated with the severity of the voltage fault, that is, the higher the alarm level, the farther the voltage deviates from the normal range and the more serious the fault. For undervoltage faults, the control logic is that the alarm voltage threshold decreases step by step from the first level to the last level, and the corresponding fault protection operation is enhanced step by step, for example, the switching speed of the switch assembly is getting faster and faster and / or the degree of cutting off the switch assembly is getting higher and higher. Taking the undervoltage fault of the battery cell as an example, the lowest voltage of all the battery cell voltages can be compared with the alarm voltage thresholds of each alarm level set to determine the alarm level of the current voltage fault. For overvoltage faults, the control logic is that the alarm voltage threshold increases step by step from the first level to the last level, and the corresponding fault protection operation is enhanced step by step. It can be understood that the fault protection operation intensity corresponding to the single cell undervoltage fault, the battery assembly total voltage undervoltage fault, the battery cell overvoltage fault and the battery assembly total voltage overvoltage fault is the same at the same level.

[0082] Exemplarily, the preset alarm level range includes: other alarm levels except the first and last alarm levels. The first alarm level is the first alarm level. For the fault of this level is minor, the fault protection operation can be set to only alarm but not disconnect the switch component. Therefore, there is no need to shield the fault protection operation of this alarm level during the forced charging and discharging process; when the system has a second-level alarm or above, the fault protection operation can be set to disconnect the switch component to achieve the purpose of not being able to charge and discharge the battery component through the high-voltage circuit, and to achieve fault protection; the tail alarm level is the last alarm level. At this level, the fault is serious, and the risk of the switch component turning on again is too great, and the switch component is not allowed to turn on again. Therefore, the preset alarm level range provided in this embodiment is equivalent to comprehensively considering the specific fault protection operations under each alarm level and the risk of shutting down the fault protection operation under each alarm level, which can make the forced charging and discharging strategy more scientific and reliable. Exemplarily, there are four alarm levels for voltage faults in total, and the preset alarm level range includes: the second and third alarm levels.

[0083] It should be noted that, in the process of forced charging and discharging, the embodiment of the present invention only turns off (or shields) the fault protection operations corresponding to each voltage fault within the preset alarm level range, and does not turn off other fault voltage alarm levels, and fault protection operations under other fault types. For example, if a fault type such as overcurrent or overtemperature that requires the switch component to be disconnected occurs during the forced charging and discharging process, the control component can still perform the fault protection operation corresponding to the fault type and normally control the switch component to be disconnected to ensure system safety.

[0084] Figure 3 FIG. 1 is a flow chart of another method for forcing a battery system to charge and discharge according to an embodiment of the present invention. Figure 3 The forced charging and discharging method of the battery system specifically includes the following steps:

[0085] S210, determining whether a mandatory control instruction issued by the energy storage converter is received; if so, executing S220; if not, terminating this control.

[0086] S220, determining whether the alarm level of the voltage fault in the battery assembly is within a preset alarm level range; if so, executing S230; if not, terminating this control.

[0087] If there is no voltage fault within the preset alarm level range, it may be the following:

[0088] 1) There is no voltage fault alarm or the alarm level is lower than the lower limit of the preset alarm level range. This indicates that the forced control command sent by the energy storage converter is wrong. At this time, the command can be ignored to control the normal operation of the system. Among them, the reasons for the error of the forced control command are: 1. To prevent the battery system from over-discharging, the energy storage converter will immediately issue a forced charging command when the SOC is lower than 2%, but there is no undervoltage fault in the system at this time, or the undervoltage fault alarm level does not reach the corresponding preset alarm level range; 2. Communication errors will cause the forced control command to be sent incorrectly.

[0089] 2) The alarm level of the voltage fault is higher than the upper limit of the preset alarm level range. This indicates that the voltage fault is serious and the switch component can no longer be controlled to conduct. Forced charging and discharging through the original charging and discharging circuit is not supported and timely fault inspection and repair are required.

[0090] S230: Turn off the fault protection operation corresponding to the voltage fault within the preset alarm level range, and turn on the forced charge and discharge operation.

[0091] S240: Count the action durations corresponding to the preset actions.

[0092] This step is performed after the forced charge and discharge operation is turned on. When the preset action is charging, the charging time is counted, and when the preset action is discharging, the discharging time is counted.

[0093] S250, determine whether the action duration exceeds the preset duration; if so, execute S270; if not, execute S260.

[0094] The preset duration may be set according to the performance of the battery assembly, for example, it may be set according to actual calculation or based on an empirical value. The preset duration is, for example, a preset charging / discharging duration for charging / discharging the battery assembly from an undervoltage / overvoltage state to a normal voltage range. The preset charging duration and the preset discharging duration may be the same or different. Exemplarily, the preset charging duration and the preset discharging duration are the same preset duration, for example, 5 minutes.

[0095] S260: Continue to perform the forced charge and discharge operation.

[0096] Among them, when the action duration does not exceed the preset duration, the fault protection operation corresponding to the voltage fault within the preset alarm level range can continue to be closed, and the forced charge and discharge operation can be performed to continue charging / discharging the battery assembly.

[0097] S270, judging whether the preset action actually occurs according to the electrical parameters of the battery assembly; if so, executing S280; if not, executing S290.

[0098] Among them, when the action duration exceeds the preset duration, the battery assembly has been successfully charged and discharged according to the expected charging and discharging progress. At this time, it is possible to determine whether the preset action actually occurs based on the current electrical parameters of the battery assembly, such as voltage or current, and then confirm whether the forced control instruction is an instruction sent by the energy storage converter in error, so as to confirm the subsequent processing flow.

[0099] S280: Start the fault protection operation corresponding to the voltage fault within the preset alarm level range, and wait for receiving the forced control end instruction corresponding to the forced control instruction issued by the energy storage converter.

[0100] Among them, when the preset action has occurred, the energy storage inverter will further determine whether the preset action is completed based on the operating parameters of the battery component uploaded by the control component, and send the corresponding forced control end instruction to the control component when the preset action is completed as the end mark of this forced charging and discharging. Then, when the control component determines that the preset action has occurred, it can first turn on the fault protection operation corresponding to the voltage fault within the preset alarm level range, which is equivalent to unshielding the fault protection operation corresponding to the voltage fault within the preset alarm level range, returning to normal voltage fault protection, and then waiting for the forced control end instruction to complete this forced charging and discharging control. Among them, the end mark corresponding to the forced charging instruction is the forced charging end instruction, and the end mark corresponding to the forced discharging instruction is the forced discharging end instruction.

[0101] S290: Start the fault protection operation corresponding to the voltage fault within the preset alarm level range, and wait for receiving the next forced control instruction issued by the energy storage converter.

[0102] Among them, when the preset action does not occur, the energy storage converter does not actually perform the operations related to forced charging and discharging, so there is no forced control end instruction as the end mark of this forced charging and discharging. In this case, the control component directly resumes the fault protection operation corresponding to the voltage fault within the preset alarm level range, which is equivalent to completing this forced charging and discharging control, and can enter the state of waiting to receive the next forced control instruction, that is, it can enter S210 in the next charging and discharging control process.

[0103] The embodiment of the present invention provides a forced charging and discharging method for a battery system through S210-S290. After the forced charging and discharging operation is turned on, after a preset time, it is determined whether the preset action occurs according to the electrical parameters of the battery assembly. It is mainly to judge the situation that the forced control instruction is issued but the energy storage converter does not actually charge and discharge the battery assembly. At the same time, the effect of forced charging and discharging can be determined, so as to restore the original voltage fault protection in time and enter the next forced charging and discharging control, so as to avoid the strategy staying in the state of forced control switch component conduction, so that when there is no forced charging / discharging, the switch component is controlled to be disconnected in time through the original voltage fault protection strategy to ensure the safety of the system. For example, it can avoid the system from self-consuming electricity in the undervoltage mode and causing irreversible losses. Exemplarily, during the timing period, the control component can continuously obtain the forced control instruction, and the energy storage converter can, for example, send the forced control instruction once every 100ms.

[0104] On the basis of the above embodiments, optionally, the battery assembly includes a plurality of cells connected in series between the positive electrode and the negative electrode of the battery assembly, and the electrical parameters of the battery assembly include: the maximum voltage of the single cell voltage of each cell, and the operating current flowing through the battery assembly. Then, the above S270 specifically includes:

[0105] When the maximum voltage satisfies the preset voltage condition, and / or the action current satisfies the preset current condition, it is determined that the preset action has actually occurred.

[0106] That is, when at least one of the voltage preset condition and the current preset condition is met, it can be considered that the preset action has actually occurred, and the instruction issued by the energy storage converter is consistent with the executed action. It can be understood that the two judgment conditions are in a parallel relationship, and satisfying any one of them can determine that the system has entered the state of forced charging / discharging, and only needs to wait for the forced control end instruction corresponding to the forced control instruction to determine that the forced charging / discharging has been completed. And, when it is determined that the preset action has occurred, the original fault protection operation is restored, which can achieve the purpose of protecting the battery system.

[0107] When the maximum voltage does not satisfy the voltage preset condition, and the action current does not satisfy the current preset condition, it is determined that the preset action does not actually occur.

[0108] That is, when both the voltage preset condition and the current preset condition are not met, it can be considered that the preset action has not actually occurred, and the instruction issued by the energy storage converter is inconsistent with the executed action.

[0109] Among them, when the forced control instruction is a forced charging instruction, the maximum voltage is the lowest voltage among the single cell voltages of each battery cell, and the action current is the charging current; the voltage preset condition is: the lowest voltage is greater than the first voltage threshold; the current preset condition is: the charging current is greater than the first current value and the duration of the charging current is greater than the first preset time. The first voltage threshold can be determined according to the actual working characteristics of the battery cell, for example, it can be set to a smaller value within the normal working voltage range, specifically 3.2V; the first current value and the first preset time can be determined according to the actual working characteristics of the battery assembly, for example, the first current value is 1A, and the first preset time is 5s.

[0110] When the forced control instruction is a forced discharge instruction, the maximum voltage is the highest voltage among the single cell voltages of each battery cell, and the action current is the discharge current; the voltage preset condition is: the highest voltage is less than the second voltage threshold; the current preset condition is: the discharge current is greater than the second current value and the duration of the discharge current is greater than the second preset time; wherein the second voltage threshold is greater than the first voltage threshold. The second voltage threshold can be determined according to the actual working characteristics of the battery cell, for example, it can be set to a larger value within the normal working voltage range, specifically 3.45V; the second current value and the second preset time can be determined according to the actual working characteristics of the battery assembly, the first current value and the second current value can be the same or different, and the first preset time and the second preset time can be the same or different; for example, the second current value is 1A, and the second preset time is 5s.

[0111] Figure 4is a flowchart of determining whether a preset action actually occurs, provided by an embodiment of the present invention. Figure 4 In a specific implementation manner, optionally, the specific steps of the above S270 include:

[0112] S310, obtaining the maximum voltage and the operating current.

[0113] S320, determining whether the maximum voltage meets a preset voltage condition; if so, executing S330; if not, executing S340.

[0114] S330: Determine whether the preset action has actually occurred.

[0115] S340, determine whether the action current meets the current preset condition; if so, execute S330; if not, execute S350.

[0116] S350: Determine whether the preset action actually does not occur.

[0117] This embodiment provides a specific judgment process of whether the preset action actually occurs through S310-S350, but it is not intended to limit the present invention. In other embodiments, S320 and S340 may be adjusted in sequence, for example, the judgment of S340 is performed first, and then the judgment of S320 is performed, or the judgment of S320 and S340 may be performed simultaneously.

[0118] On the basis of the above-mentioned embodiments, optionally, before starting the forced charge and discharge operation, it further includes: judging whether a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter is received; if so, stopping the forced charge and discharge operation, and starting the fault protection operation corresponding to the voltage fault within the preset alarm level range; if not, starting the forced charge and discharge operation, and counting the action duration corresponding to the preset action. Accordingly, when the action duration does not exceed the preset duration, return to the step of judging whether a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter is received.

[0119] This embodiment is set up in this way, which is equivalent to judging in real time whether the energy storage converter has issued a forced control end instruction during the timing process. The energy storage converter also judges in real time whether the preset action is completed during the execution of the preset action. In actual application, it is very likely that the charging and discharging will be completed in advance. This embodiment adds the judgment of whether the forced control end instruction is received, which is conducive to jumping out of the cycle in time when the preset action is completed, stopping the forced charging and discharging and turning on the original overvoltage fault protection, avoiding new overvoltage / undervoltage problems caused by forced charging / discharging, and ensuring the reliability of forced charging and discharging of the system.

[0120] For details, see Figure 5 The forced charging and discharging method of the battery system comprises the following steps:

[0121] S401, determine whether a mandatory control instruction issued by the energy storage converter is received; if so, execute S402; if not, end this control.

[0122] S402, determining whether the alarm level of the voltage fault in the battery assembly is within a preset alarm level range; if so, executing S403; if not, terminating this control.

[0123] S403: Turn off the fault protection operation corresponding to the voltage fault within the preset alarm level range.

[0124] Among them, this step can be regarded as a forced charge and discharge preparation step.

[0125] S404, determine whether a forced control end instruction is received; if so, execute S405; if not, execute S406.

[0126] S405: Stop the forced charge and discharge operation, and start the fault protection operation corresponding to the voltage fault within the preset alarm level range.

[0127] S406, start the forced charge and discharge operation.

[0128] S407: Count the action durations corresponding to the preset actions.

[0129] S408, determine whether the action duration exceeds the preset duration; if so, execute S409; if not, return to execute S404.

[0130] S409, obtaining the maximum voltage and operating current.

[0131] S410, judging whether at least one of the following is satisfied: the maximum voltage satisfies the voltage preset condition, and the operating current satisfies the current preset condition; if so, executing S411; if not, executing S412.

[0132] S411, start the fault protection operation corresponding to the voltage fault within the preset alarm level range, and wait for receiving the forced control end instruction corresponding to the forced control instruction issued by the energy storage converter

[0133] S412: Start the fault protection operation corresponding to the voltage fault within the preset alarm level range, and wait for receiving the next forced control instruction issued by the energy storage converter.

[0134] This embodiment provides specific steps of a method for forced charging and discharging of a battery system through S401-S412, which can safely and reliably implement forced charging and discharging of the system under a voltage fault state, and is conducive to maintaining system stability.

[0135] The control strategies for forced charging and discharging are given as examples in the above-mentioned implementation modes. The following takes the voltage fault as divided into four levels, namely, level 1, level 2, level 3 and level 4, and the preset alarm level range includes two alarm levels, level 2 and level 3, as an example to explain the specific control processes of forced charging and forced discharging respectively.

[0136] Figure 6 FIG. 1 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention. Figure 6 In one implementation, the specific process of forced charging control includes:

[0137] S501, determine whether a forced charging instruction is received; if so, execute S502; if not, end this control.

[0138] S502, determine whether there is an undervoltage fault with an alarm level of more than level 1 and less than level 4; if so, execute S503; if not, end this control.

[0139] S503: Disable the fault protection operation corresponding to the undervoltage fault at the second and third alarm levels.

[0140] S504, determining whether a forced charging end instruction is received; if so, executing S505; if not, executing S506.

[0141] S505: end forced charging, and start fault protection operations corresponding to undervoltage faults at level 2 and level 3 warning levels.

[0142] Among them, ending the forced charging means stopping the forced charging and discharging operations and restoring normal voltage fault protection related operations.

[0143] S506: Perform forced charging and count the charging time.

[0144] Among them, the forced charging is to start the forced charging and discharging operation and control the switch component to be turned on.

[0145] S507, determine whether the charging time exceeds the preset time; if so, execute S508; if not, return to execute S504.

[0146] S508: Obtain the minimum voltage and charging current.

[0147] S509, determine whether at least one of the following is satisfied: the lowest voltage is greater than a first voltage threshold, the charging current is greater than a first current value and the duration is greater than a first preset time; if so, execute S510; if not, execute S511.

[0148] S510: Start the fault protection operation corresponding to the undervoltage fault at the second and third warning levels, and wait for the forced charging end instruction.

[0149] S511 . Start the fault protection operation corresponding to the undervoltage fault at the second and third warning levels, and wait for the next forced charging instruction.

[0150] This embodiment provides a specific process of forced charging control through S501-S511.

[0151] Figure 7 FIG. 1 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention. Figure 7 In another embodiment, the specific process of forced discharge control includes:

[0152] S601, determine whether a forced discharge instruction is received; if so, execute S602; if not, end this control.

[0153] S602, determine whether there is an overvoltage fault with an alarm level of more than level 1 and less than level 4; if so, execute S603; if not, end this control.

[0154] S603: Disable the fault protection operation corresponding to the overvoltage fault at the second and third alarm levels.

[0155] S604, determine whether a forced discharge end instruction is received; if so, execute S605; if not, execute S606.

[0156] S605: end the forced discharge, and start the fault protection operation corresponding to the overvoltage fault at the second and third warning levels.

[0157] Among them, ending the forced discharge means stopping the forced charge and discharge operation and restoring normal voltage fault protection related operations.

[0158] S606: Perform forced discharge and count the discharge duration.

[0159] Among them, performing forced discharge is to start the forced charge and discharge operation and control the switch component to be turned on.

[0160] S607, determine whether the discharge time exceeds the preset time; if so, execute S608; if not, return to execute S604.

[0161] S608: Obtain the highest voltage and discharge current.

[0162] S609, determine whether at least one of the following is satisfied: the highest voltage is less than the second voltage threshold, the discharge current is greater than the second current value and the duration is greater than the second preset time; if so, execute S610; if not, execute S611.

[0163] S610: Start the fault protection operation corresponding to the overvoltage fault at the second and third alarm levels, and wait for the forced discharge end instruction.

[0164] S611 . Start the fault protection operation corresponding to the overvoltage fault under the second and third alarm levels, and wait for the next forced discharge instruction.

[0165] This embodiment provides a specific process of forced discharge control through S601-S611.

[0166] The embodiment of the present invention also provides a forced charging and discharging method of a battery system, which is applied to an energy storage converter. The forced charging and discharging method of the battery system comprises: when the operation information of the battery assembly uploaded by the control assembly meets the forced charging and discharging conditions, a forced control instruction is sent to the control assembly, and a preset action is performed on the battery assembly through the total positive terminal and the total negative terminal.

[0167] Among them, when the forced charge and discharge condition is a forced charge condition, the forced control instruction is a forced charge instruction, and the preset action is charging; when the forced charge and discharge condition is a forced discharge condition, the forced control instruction is a forced discharge instruction, and the preset action is discharging.

[0168] Understandably, the battery system can still be seen Figure 1 The structure shown in . During the operation of the battery system, the control component 30 will detect the operation information of the battery assembly 10 in real time and upload it to the energy storage inverter 40 in real time. The operation information of the battery assembly 10 includes, for example, the voltage condition, current condition, temperature condition and SOC of the battery assembly 10. The voltage condition may include the total voltage of the battery assembly 10 and the single cell voltage of each battery cell in the battery assembly 10. The control component 10 can collect and upload the operation information of the battery assembly 10 at a certain frequency, and the frequency is not limited here.

[0169] The energy storage converter 40 determines whether it is necessary to force charge and discharge the battery assembly 10 according to the operation information of the battery assembly 10. When forced charge and discharge are required, the energy storage converter 40 sends a forced control instruction to the control assembly 30, and at the same time, the energy storage converter 40 controls the energy flow to realize the charging / discharging of the battery assembly 10.

[0170] Specifically, the energy storage converter can also be connected to the power grid. When the preset action is charging, the energy storage converter uses the power grid as the power source of the battery assembly and controls the power grid to charge the battery assembly; when the preset action is discharging, the energy storage converter uses the power grid as the load of the battery assembly and controls the battery assembly to discharge to the power grid.

[0171] In the forced charging and discharging method of the battery system provided by the embodiment of the present invention, the energy storage converter determines whether it is necessary to force the battery assembly to be charged and discharged according to the operation information of the battery assembly uploaded by the control component; when forced charging and discharging is required, a forced control instruction is issued, and the preset action is performed on the battery assembly through the total positive terminal and the total negative terminal, without disassembling the battery assembly and connecting an external charger or load, but forcibly controlling the switch assembly to be turned on, and charging and discharging using the original charging and discharging circuit of the battery system. In this way, firstly, forced charging and discharging can be achieved based on the original hardware conditions, without adjusting the wiring, saving manpower and time, improving charging and discharging efficiency, and reducing disassembly and assembly losses and risks; secondly, the original charging and discharging circuit is used to directly force the entire battery assembly to be charged and discharged, without disassembling it into multiple blocks and then charging and discharging separately, which can avoid the problem of unbalanced charging and discharging and ensure the reliability and safety of the system; thirdly, there is no need to purchase / independently develop the equipment required for forced charging and discharging, which can effectively reduce costs, and the code modification is flexible, with strong portability, without destroying the existing functional modules of the control component, and without affecting other fault detection and protection functions of the system. In summary, the embodiments of the present invention can improve the efficiency of forced charging and discharging of the battery system and reduce the cost while ensuring the reliability of the battery system.

[0172] Figure 8 FIG. 1 is a flow chart of another method for forced charging and discharging of a battery system provided by an embodiment of the present invention. Figure 8 , the forced charging and discharging method of the battery system includes:

[0173] S710: When the operation information of the battery assembly uploaded by the control assembly meets the forced charge and discharge conditions, a forced control instruction is sent to the control assembly, and a preset action is performed on the battery assembly through the total positive terminal and the total negative terminal.

[0174] Among them, when the forced charge and discharge condition is a forced charge condition, the forced control instruction is a forced charge instruction, and the preset action is charging; when the forced charge and discharge condition is a forced discharge condition, the forced control instruction is a forced discharge instruction, and the preset action is discharging.

[0175] S720: When the operation information of the battery assembly uploaded by the control assembly meets the forced control stop condition corresponding to the currently executed preset action, a forced control end instruction is sent to the control assembly, and the preset action is stopped.

[0176] Among them, when the currently executed preset action is charging, the forced control stop condition is the forced charging end condition, and the forced control end instruction is the forced charging end instruction; when the currently executed preset action is discharging, the forced charging and discharging stop condition is the forced discharging end condition, and the forced control end instruction is the forced discharging end instruction.

[0177] The embodiment of the present invention provides a complete forced charge and discharge control process on the energy storage converter side, and can achieve safe and reliable forced charge and discharge based on the original structure and connection relationship of the battery system.

[0178] The embodiment of the present invention further provides a battery system, which can apply the forced charging and discharging method of the battery system provided by any of the above embodiments, and has corresponding beneficial effects. Figure 1 , the battery system may include: a battery assembly 10, a switch assembly 20, a control assembly 30 and an energy storage inverter 440. The battery assembly 10 and the switch assembly 20 are connected in series between the total positive terminal P1 and the total negative terminal P2 of the battery system, and the control assembly 30 is respectively connected to the battery assembly 10, the switch assembly 20 and the energy storage inverter 40; the energy storage inverter 40 is also respectively connected to the total positive terminal P1 and the total negative terminal P2. Among them, the control assembly 30 is used to execute the forced charging and discharging method of the battery system on the control assembly side provided in any embodiment of the present invention; the energy storage inverter 40 is used to execute the forced charging and discharging method of the battery system on the energy storage inverter side provided in any embodiment of the present invention.

[0179] Fig. 9 FIG. 1 is a schematic diagram of another battery system provided by an embodiment of the present invention. Fig. 9 In a specific embodiment, optionally, the battery assembly 10 may include a plurality of battery packs 110 connected in series between the positive electrode BAT1 and the negative electrode BAT2 of the battery assembly 10, the battery pack 110 may include a battery module 111 and a battery management unit BMU, the battery module 111 includes a plurality of battery cells E connected in series, and the battery management unit BMU is used to collect operating parameters such as voltage and temperature of each battery cell E in the battery module 111, and to perform balanced management of the battery module 111.

[0180] The switch assembly 20 may include a first switch unit 210 and a second switch unit 220. The first switch unit 210 is connected between the positive electrode BAT1 of the battery assembly 10 and the total positive terminal P1, and the second switch unit 220 is connected between the negative electrode BAT2 of the battery assembly 10 and the total negative terminal P2.

[0181] The control component 30 may include a slave battery management unit SBMU and a master battery management unit MBMU, wherein the slave battery management unit SBMU is connected to the battery management unit BMU in each battery pack 110 and is connected to the master battery management unit MBMU, and the master battery management unit MBMU is connected to the energy storage converter 40. Exemplarily, the master battery management unit MBMU communicates with the slave battery management unit SBMU and the energy storage converter 40 via a CAN (Controller Area Network) protocol.

[0182] The energy storage converter 40 is also connected to the power grid 50 to control the power grid 50 as a power source or load of the battery assembly 10 during the forced charging and discharging process.

[0183] Among them, the control component 30 and each battery management unit BMU can be used as a component of the battery management system (BMS). The battery assembly 10, and at least part of the control component 30 can be integrated in the battery cabinet 1000; for example, the battery assembly 10 and the slave battery management unit SBMU are integrated in the battery cabinet 1000, and the slave battery management unit SBMU is the control board in the battery cabinet 1000; the master battery management unit MBMU is a cabinet control board, which connects the slave battery management units SBMU in each battery cabinet 1000. Each battery cabinet 1000 can share the same master battery management unit MBMU and the same energy storage inverter 40, and the battery assembly 10 in any battery cabinet 1000 can be forced to charge and discharge using the forced charge and discharge method of the battery system provided in any of the above embodiments. The battery cabinet 1000 can specifically be a production cabinet or a test cabinet, which is not specifically limited here.

[0184] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0185] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A forced charging and discharging method for a battery system, characterized in that: The battery system comprises: a battery assembly, a switch assembly, a control assembly and an energy storage converter; the battery assembly and the switch assembly are connected in series between the total positive terminal and the total negative terminal of the battery system, the control assembly is respectively connected to the battery assembly, the switch assembly and the energy storage converter; the energy storage converter is also respectively connected to the total positive terminal and the total negative terminal; the forced charging and discharging method of the battery system is executed by the control assembly; the forced charging and discharging method of the battery system comprises: When receiving the forced control instruction sent by the energy storage converter, and the alarm level of the voltage fault in the battery assembly is within the preset alarm level range, the fault protection operation corresponding to the voltage fault within the preset alarm level range is turned off, and the forced charge and discharge operation is turned on; wherein the fault protection operation corresponding to the voltage fault within the preset alarm level range includes: controlling the switch assembly to be disconnected; the forced charge and discharge operation includes: controlling the switch assembly to be turned on, so that the energy storage converter can perform a preset action on the battery assembly through the total positive terminal and the total negative terminal; Among them, when the forced control instruction is a forced charging instruction, the voltage fault is an undervoltage fault, and the preset action is charging; when the forced control instruction is a forced discharging instruction, the voltage fault is an overvoltage fault, and the preset action is discharging.

2. The forced charge and discharge method of the battery system according to claim 1, characterized in that: After the fault protection operation corresponding to the voltage fault within the preset alarm level range is turned off and the forced charge and discharge operation is turned on, the method further includes: Counting the action duration corresponding to the preset action; When the duration of the action exceeds the preset duration, judging whether the preset action actually occurs according to the electrical parameters of the battery assembly; When the action duration does not exceed the preset duration, continuing to perform the forced charge and discharge operation; Wherein, if the preset action has actually occurred, the forced charging and discharging method of the battery system further includes: starting a fault protection operation corresponding to a voltage fault within the preset alarm level range, and waiting to receive a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter; If the preset action does not actually occur, the forced charging and discharging method of the battery system further includes: starting a fault protection operation corresponding to a voltage fault within the preset alarm level range, and waiting to receive a next forced control instruction issued by the energy storage converter.

3. The forced charge and discharge method of the battery system according to claim 2, characterized in that: The battery assembly comprises a plurality of cells connected in series between a positive electrode and a negative electrode of the battery assembly, and the electrical parameters of the battery assembly comprise: a maximum voltage among the single cell voltages of each of the cells, and an operating current flowing through the battery assembly; Determining whether the preset action actually occurs according to the electrical parameters of the battery assembly includes: When the maximum voltage satisfies a preset voltage condition, and / or the action current satisfies a preset current condition, it is determined that the preset action has actually occurred; When the maximum voltage does not satisfy the preset voltage condition, and the action current does not satisfy the preset current condition, it is determined that the preset action does not actually occur.

4. The forced charge and discharge method of the battery system according to claim 3, characterized in that: When the forced control instruction is a forced charging instruction, the maximum voltage is the lowest voltage among the single cell voltages of the battery cells, and the action current is the charging current; the voltage preset condition is: the lowest voltage is greater than a first voltage threshold; the current preset condition is: the charging current is greater than a first current value and the duration of the charging current is greater than a first preset time; When the forced control instruction is a forced discharge instruction, the maximum voltage is the highest voltage among the single cell voltages of each of the battery cells, and the action current is the discharge current; the voltage preset condition is: the highest voltage is less than the second voltage threshold; the current preset condition is: the discharge current is greater than the second current value and the duration of the discharge current is greater than the second preset time; wherein, the second voltage threshold is greater than the first voltage threshold.

5. The forced charge and discharge method for a battery system according to any one of claims 2 to 4, characterized in that: Before starting the forced charge and discharge operation, the method further includes: Determining whether a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter is received; If yes, stop the forced charge and discharge operation, and start the fault protection operation corresponding to the voltage fault within the preset alarm level range; If not, start the forced charge and discharge operation, and count the action duration corresponding to the preset action; Correspondingly, when the action duration does not exceed the preset duration, the process returns to the step of determining whether a forced control end instruction corresponding to the forced control instruction issued by the energy storage converter is received.

6. The forced charge and discharge method of a battery system according to claim 1, characterized in that: The battery assembly includes a plurality of battery cells connected in series between a positive electrode and a negative electrode of the battery assembly; The undervoltage fault includes: a single cell undervoltage fault and a battery assembly total voltage undervoltage fault; The overvoltage fault includes: battery cell single voltage fault and battery assembly total voltage overvoltage fault; and / or, The alarm level of the voltage fault in the battery assembly includes at least three alarm levels; wherein the number of the alarm levels is positively correlated with the severity of the voltage fault; The preset alarm level range includes: other alarm levels except the first and last alarm levels.

7. A forced charging and discharging method for a battery system, characterized in that: The battery system comprises: a battery assembly, a switch assembly, a control assembly and an energy storage converter; the battery assembly and the switch assembly are connected in series between the total positive terminal and the total negative terminal of the battery system, the control assembly is respectively connected to the battery assembly, the switch assembly and the energy storage converter; the energy storage converter is also respectively connected to the total positive terminal and the total negative terminal; the forced charging and discharging method of the battery system is executed by the energy storage converter; the forced charging and discharging method of the battery system comprises: When the operation information of the battery assembly uploaded by the control component meets the forced charge and discharge conditions, a forced control instruction is issued to the control component, and a preset action is performed on the battery assembly through the total positive terminal and the total negative terminal; Among them, when the forced charge and discharge condition is a forced charge condition, the forced control instruction is a forced charge instruction, and the preset action is charging; when the forced charge and discharge condition is a forced discharge condition, the forced control instruction is a forced discharge instruction, and the preset action is discharging.

8. The forced charge and discharge method of the battery system according to claim 7, characterized in that: After issuing a forced control instruction to the control component and performing a preset action on the battery component through the total positive terminal and the total negative terminal, the method further includes: When the operation information of the battery assembly uploaded by the control component meets the forced control stop condition corresponding to the preset action currently being executed, a forced control end instruction is sent to the control component, and the preset action is stopped; Among them, when the currently executed preset action is charging, the forced control stop condition is the forced charging end condition, and the forced control end instruction is the forced charging end instruction; when the currently executed preset action is discharging, the forced charging and discharging stop condition is the forced discharging end condition, and the forced control end instruction is the forced discharging end instruction.

9. The forced charge and discharge method of the battery system according to claim 8, characterized in that: The energy storage converter is also connected to the power grid; When the preset action is charging, the energy storage inverter uses the power grid as the power source of the battery assembly; when the preset action is discharging, the energy storage inverter uses the power grid as the load of the battery assembly.

10. A battery system, characterized in that: include: A battery assembly, a switch assembly, a control assembly and an energy storage converter; the battery assembly and the switch assembly are connected in series between the total positive terminal and the total negative terminal of the battery system, the control assembly is respectively connected to the battery assembly, the switch assembly and the energy storage converter; the energy storage converter is also respectively connected to the total positive terminal and the total negative terminal; The control component is used to execute the forced charging and discharging method of the battery system described in any one of claims 1-6; the energy storage inverter is used to execute the forced charging and discharging method of the battery system described in any one of claims 7-9.

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