Energy storage system and battery pack charging and discharging control method

Abstract

The invention provides an energy storage system and a battery pack charging and discharging control method, and is applied to the technical field of energy storage. The energy storage system comprises a battery pack and a controller, the controller is used for controlling charging and discharging of the battery pack, and the controller is specifically used for controlling charging and discharging of the battery pack when the voltage change rate of the battery pack within a preset time period is smaller than a preset change rate or the battery pack is in a standby power mode in the operation process of the battery pack. And if the maximum charge-discharge capacity allowed by the battery pack is less than or equal to the first preset charge-discharge capacity, controlling the maximum charge-discharge capacity allowed by the battery pack to be increased to a second preset charge-discharge capacity greater than the first preset charge-discharge capacity, and controlling the charge-discharge capacity of the battery pack to be less than or equal to the second preset charge-discharge capacity. Therefore, the operation range of the battery pack is expanded, so that the battery pack can charge and release more electric quantity, the electricity demand of a user is met, the charge and discharge availability of the battery pack is improved, and the user experience is improved.

Description

Technical Field

[0001] This application relates to the technical field of energy storage, and in particular, to an energy storage system and a control method for charging and discharging a battery pack. Background Art

[0002] In energy storage technology, accurately detecting the State of Charge (SOC) of a battery pack is crucial. Currently, most of the batteries used in energy storage systems are non-linear complex electrochemical systems. For example, lithium iron phosphate batteries have many influencing factors for their characteristics, and it is difficult to accurately calculate the SOC of the battery pack during the operation of the battery pack. Inaccurate SOC will lead to inaccurate estimation of the battery pack's power, thereby reducing the availability of the battery pack and affecting the user experience. For example, inaccurate SOC during charging will cause premature determination that the battery is fully charged when it is actually not, affecting the protection mechanism of the battery pack. Another example is that inaccurate SOC during discharging will cause premature triggering of protection, etc. Summary of the Invention

[0003] Embodiments of this application provide an energy storage system and a control method for charging and discharging a battery pack to improve the availability of the battery pack and improve the user experience.

[0004] In a first aspect, embodiments of this application provide an energy storage system. The energy storage system includes a battery pack and a controller, and the controller is used to control the charging and discharging of the battery pack. Specifically, the controller is configured to: during the operation of the battery pack, when the voltage change rate of the battery pack within a preset time period is less than a preset change rate or the battery pack is in a standby power mode, and the maximum allowable charge and discharge amount of the battery pack is less than or equal to a first preset charge and discharge amount, control the maximum allowable charge and discharge amount of the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount.

[0005] Wherein, the maximum allowable charge and discharge amount of the battery pack refers to the maximum amount of electricity that the battery pack can actually allow to be charged and discharged. The maximum allowable charge and discharge amount of the battery pack is less than the rated charge and discharge amount of the battery pack. The rated charge and discharge amount refers to the maximum amount of electricity that the battery pack can be charged and discharged under standard charge and discharge conditions.

[0006] In this embodiment, by setting a first preset charge and discharge amount, the maximum charge and discharge amount allowed when the battery pack starts to operate is limited to ensure the safe use and service life of the battery pack. When it is detected that the voltage change rate of the battery pack within a preset time period is less than a preset change rate or the battery pack is in the standby power mode, and the maximum charge and discharge amount allowed by the battery pack is less than or equal to the first preset charge and discharge amount, the controller controls the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and controls the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount, releasing the operating range of the battery pack, so that the battery pack can charge and discharge more power, meet the user's power consumption needs, improve the charge and discharge availability of the battery pack, and improve the user experience.

[0007] In an embodiment of the first aspect, the controller is further configured to: when the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate and the battery pack is in the non-standby power mode, and the maximum charge and discharge amount allowed by the battery pack is greater than or equal to the first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the third preset charge and discharge amount.

[0008] In this embodiment, when the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate or the battery pack is in the non-standby power mode, and the maximum charge and discharge amount allowed by the battery pack is greater than or equal to the first preset charge and discharge amount, the controller controls the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, and controls the charge and discharge amount of the battery pack to be less than or equal to the third preset charge and discharge amount, so that the relationship between the SOC and the charge and discharge amount during the operation of the battery pack is closer to linear, and the change of the SOC can accurately match the charged / discharged power, further improving the user experience. At the same time, the maximum charge and discharge amount allowed by the battery pack is reduced, which can improve the charge and discharge efficiency of the battery pack and protect the service life of the battery pack.

[0009] In an embodiment of the first aspect, the controller is specifically configured to: control the upper SOC cut-off value allowed for the battery pack to increase, and / or control the lower SOC cut-off value allowed for the battery pack to decrease.

[0010] In this embodiment, by controlling the upper SOC cut-off value allowed for the battery pack to increase, and / or controlling the lower SOC cut-off value allowed for the battery pack to decrease, the controller can accurately control the maximum charge and discharge amount allowed by the battery pack to increase to the second preset charge and discharge amount, release the operating range of the battery pack, so that the battery pack can charge and discharge more power, meet the user's power consumption needs, improve the charge and discharge availability of the battery pack, and improve the user experience.

[0011] In an embodiment of the first aspect, the controller is specifically configured to: control the upper SOC cut-off value allowed for use by the battery pack to decrease, and / or control the lower SOC cut-off value allowed for use by the battery pack to increase.

[0012] In this embodiment, by controlling the upper SOC cut-off value allowed for use by the battery pack to decrease, and / or controlling the lower SOC cut-off value allowed for use by the battery pack to increase, the controller can accurately control the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount, so that the relationship between SOC and the battery level during the operation of the battery pack is closer to linear, and the change in SOC can accurately match the charged / discharged battery level, further improving the user experience. At the same time, the decrease in the maximum charge and discharge amount allowed by the battery pack can improve the charge and discharge efficiency of the battery pack and protect the service life of the battery pack.

[0013] In an embodiment of the first aspect, the controller is specifically configured to: control the upper SOC cut-off value allowed for use by the battery pack to change at a first rate, and / or control the lower SOC cut-off value allowed for use by the battery pack to change at a second rate, where both the first rate and the second rate are less than a rate threshold.

[0014] In this embodiment, by setting the rate threshold, the first rate, and the second rate, the controller controls the upper SOC cut-off value allowed for use by the battery pack to change at a first rate less than the rate threshold, and / or the lower SOC cut-off value to change at a second rate less than the rate threshold, solving the problem that the current SOC displayed on the display screen jumps due to the jump of the lower SOC cut-off value and the upper SOC cut-off value, enabling the adjustment of the maximum charge and discharge amount allowed by the battery pack without the user's awareness and improving the user experience.

[0015] In an embodiment of the first aspect, the controller is specifically configured to: calculate the first rate according to the change amount of the upper SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen of the energy storage system, and the charge and discharge current of the battery pack; calculate the second rate according to the change amount of the lower SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen of the energy storage system, and the charge and discharge current of the battery pack.

[0016] In this embodiment, when calculating the first rate and the second rate, the controller comprehensively considers the change amount of the SOC upper limit cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen, and the current of the battery pack charging and discharging, so that the SOC upper limit cut-off value changes at the calculated first rate and / or the SOC lower limit cut-off value changes at the calculated second rate to adapt to the current working condition of the battery pack and the change of the current SOC displayed on the display screen, solving the problem that the jump of the SOC lower limit cut-off value and the SOC upper limit cut-off value causes the jump of the current SOC displayed on the display screen, enabling the maximum charge and discharge amount allowed by the battery pack to be adjusted without the user's awareness and improving the user experience.

[0017] In an embodiment of the first aspect, the controller is specifically configured to: during the process of controlling the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount or controlling the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, the current SOC of the battery pack displayed on the display screen of the energy storage system changes at a third rate.

[0018] In this embodiment, during the process of controlling the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount or controlling the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, the controller controls the current SOC of the battery pack displayed on the display screen to change at a third rate, so that the current SOC displayed on the display screen changes with the change of the maximum charge and discharge amount allowed by the battery pack, and the user can directly obtain the SOC after the change of the maximum charge and discharge amount allowed by the battery pack from the display screen. At the same time, the current SOC changes at a third rate, avoiding the occurrence of the jump phenomenon of the current SOC displayed on the display screen and improving the user experience.

[0019] In an embodiment of the first aspect, the controller is specifically configured to: in response to a user configuration operation, control the SOC lower limit cut-off value allowed to be used by the battery pack to be the SOC lower limit cut-off value indicated by the user configuration operation and the SOC upper limit cut-off value allowed to be used by the battery pack to be the SOC upper limit cut-off value indicated by the user configuration operation.

[0020] In this embodiment, the user can set the SOC lower limit cut-off value and the SOC upper limit cut-off value allowed to be used by the battery pack through a user configuration operation, so that the maximum charge and discharge amount allowed by the battery pack can meet the user's charge and discharge requirements, improving the user experience.

[0021] Second aspect, an embodiment of the present application provides a control method for charging and discharging a battery pack, which is used for an energy storage system. The energy storage system includes a battery pack and a controller, and the control method is executed by the controller. During the operation of the battery pack, when the voltage change rate of the battery pack within a preset time period is less than a preset change rate or in a standby power mode, and the maximum charge and discharge amount allowed by the battery pack is less than or equal to a first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount.

[0022] In an embodiment of the second aspect, when the voltage change rate of the battery pack within a preset time period is greater than or equal to the preset change rate or in a non-standby power mode, and the maximum charge and discharge amount allowed by the battery pack is greater than or equal to the first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the third preset charge and discharge amount.

[0023] For the supplement and technical effects of the solution provided in the second aspect above, reference may be made to the corresponding description in the first aspect, which will not be repeated here. Description of the Drawings

[0024] Figure 1 Shows a schematic diagram of an energy storage system provided by an embodiment of the present application;

[0025] Figure 2 Shows a timing diagram of the control process of a controller provided by an embodiment of the present application;

[0026] Figure 3 Shows a schematic diagram of the maximum charge and discharge amount of a battery pack provided by an embodiment of the present application;

[0027] Figure 4 Shows a timing diagram of the control process of another controller provided by an embodiment of the present application;

[0028] Figure 5 Shows a schematic diagram of the maximum charge and discharge amount of another battery pack provided by an embodiment of the present application;

[0029] Figure 6 Shows a flowchart of the internal logic of a controller provided by an embodiment of the present application;

[0030] Figure 7 Shows a schematic diagram of a controller provided by an embodiment of the present application;

[0031] Figure 8 Shows a flowchart of the internal logic of another controller provided by an embodiment of the present application. Detailed Embodiments

[0032] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0033] The prefixes such as "first" and "second" used in the embodiments of the present application are only used to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers used to distinguish description objects in the embodiments of the present application does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and the use of such prefixes should not constitute an unnecessary limitation.

[0034] In energy storage technology, it is crucial to accurately detect the state of charge (SOC) of the battery pack. Currently, the batteries used in most energy storage systems are nonlinear and complex electrochemical systems, such as lithium iron phosphate batteries. There are many factors that affect their characteristics, and it is difficult to accurately calculate the SOC of the battery pack during the operation of the battery pack. Inaccurate SOC will lead to inaccurate estimation of the battery pack's power, thereby reducing the availability of the battery pack and affecting the user experience. For example, inaccurate SOC during charging will lead to premature judgment that the battery is fully charged when it is not, etc., affecting the protection mechanism of the battery pack. For another example, inaccurate SOC during discharge will cause protection to be triggered prematurely, etc.

[0035] In order to ensure the service life and safety of the battery pack, the maximum charge and discharge amount allowed by the battery pack is usually limited, that is, the battery pack will not be frequently fully charged and discharged during operation. The maximum charge and discharge amount allowed by the battery pack can be limited by voltage locking, that is, when discharging, the voltage of the battery pack reaches a specified voltage (for example, 2.5V), and the battery management system locks the battery pack, and the battery no longer discharges. The same is true when charging. For battery packs such as lithium iron phosphate batteries that have a voltage plateau period, due to the existence of the lock function, the battery pack cannot be calibrated for SOC, and the SOC accuracy is low. In this case, there will also be problems such as inaccurate battery pack power estimation and impact on the protection mechanism of the battery pack, which will reduce the availability of the battery pack and affect the user experience. At the same time, since the voltage change amplitude is small in the voltage platform area, voltage locking is not applicable.

[0036] In view of this, an embodiment of the present application provides a control method for an energy storage system and battery pack charging and discharging. When it is detected that the voltage change rate of the battery pack within a preset time period is less than a preset change rate or the battery pack is in a standby power mode, and the maximum allowable charge and discharge amount of the battery pack is less than or equal to a first preset charge and discharge amount, the maximum allowable charge and discharge amount of the battery pack is controlled to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and the charge and discharge amount of the battery pack is controlled to be less than or equal to the second preset charge and discharge amount, thereby releasing the operating range of the battery pack, enabling the battery pack to charge and discharge more electricity, meeting the user's power consumption requirements, improving the charge and discharge availability of the battery pack, and enhancing the user experience.

[0037] Please refer to Figure 1 , Figure 1 which shows a schematic diagram of an energy storage system 100. Among them, the energy storage system 100 includes a battery pack 101 and a controller 102. The energy storage system 100 can be applied to devices such as electric vehicles and 5G base stations. The battery pack 101 is used to output electrical energy to a load (such as an electric vehicle, industrial equipment, etc.) or receive electrical energy input from a power generation system (such as a photovoltaic system, a wind power generation system, etc.). The controller 102 is used to adjust the maximum allowable charge and discharge amount of the battery pack and to control the charge and discharge amount of the battery pack to be less than or equal to the maximum allowable charge and discharge amount.

[0038] Among them, there can be multiple battery packs 101 in the energy storage system. The battery pack 101 can be a single battery or a battery cluster composed of multiple batteries. Among them, the batteries in the battery pack can also be a combination of one or more of lead-carbon batteries, lithium iron phosphate batteries, ternary lithium batteries, sodium-sulfur batteries, and flow batteries, which is not specifically limited in the embodiments of the present application.

[0039] Among them, the controller 102 can be a general-purpose central processing unit (CPU), a general-purpose processor, a digital signal processing (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of the present application. The above processor can also be a combination that realizes computing functions, such as a combination of one or more microprocessors, a combination of DSP and a microprocessor, and so on.

[0040] In one embodiment, the controller 102 may further include a battery management system (BMS), which can obtain the current status of the battery pack (such as basic battery information such as the voltage, current, and temperature of the battery pack) by performing online monitoring on the battery pack.

[0041] Specifically, the BMS includes a Battery Management Unit (BMU) and a Battery Control Unit (BCU). The BMU is used to monitor the battery pack and perform local balancing control, etc.; the BCU is used to manage the charging and discharging, safety protection, etc. of the battery pack according to the data provided by the BMU.

[0042] The architecture of the embodiments of the present application has been described above. Next, the energy storage system provided by the present application will be described in conjunction with specific embodiments.

[0043] In the embodiments of the present application, a controller 102 is provided. The controller 102 is specifically configured to: during the operation of the battery pack, when the voltage change rate of the battery pack within a preset time period is less than a preset change rate or in the standby power mode, and the maximum charge and discharge amount allowed by the battery pack is less than or equal to a first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount.

[0044] Among them, the maximum charge and discharge amount allowed by the battery pack refers to the maximum amount of electricity that the battery pack can actually charge and discharge. The maximum charge and discharge amount allowed by the battery pack is less than the rated charge and discharge amount of the battery pack. The rated charge and discharge amount refers to the maximum amount of electricity that the battery pack can charge and discharge under standard charge and discharge conditions. For example, if the rated charge and discharge amount is 100 ampere-hours, the maximum charge and discharge amount allowed by the battery pack can be 80 ampere-hours.

[0045] In the embodiments of the present application, the specific values of the first preset charge and discharge amount and the second preset charge and discharge amount are not limited. The purpose of setting the first preset charge and discharge amount is to limit the maximum charge and discharge amount allowed when the battery pack starts to operate, and ensure the use safety and service life of the battery pack. It can be, for example, 100 ampere-hours, 150 ampere-hours, 200 ampere-hours, etc. The first preset charge and discharge amount is less than the second charge and discharge amount.

[0046] In the embodiments of the present application, the specific values of the preset change rate and the preset time period are not limited.

[0047] It can be known that when the battery pack is operating in the voltage plateau region, the voltage change is relatively gentle, that is, the voltage change rate is small, and the state of charge (SOC) of the battery pack cannot be calibrated through the corresponding relationship between the voltage and the SOC, and the SOC accuracy of the battery pack is low.

[0048] Among them, the voltage plateau region refers to the region where the voltage changes relatively gently during the charging and discharging process of the battery pack. For example, the voltage plateau region of a lithium iron phosphate battery corresponds to a SOC range of approximately 15 - 95%. SOC is the State of Charge, which refers to the ratio of the remaining power of the battery pack to the rated power of the battery pack, usually expressed as a percentage.

[0049] If the voltage change rate of the battery pack within a preset time period is less than the preset change rate, it is considered that the battery pack is in the voltage plateau region, and there is no deep charging and discharging within the preset time period. The SOC accuracy of the battery pack is relatively low, and the charging and discharging of the battery pack cannot be accurately controlled based on SOC, resulting in a relatively low charging and discharging availability of the battery pack.

[0050] In this case, by controlling the maximum allowable charge and discharge amount of the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, the operating range of the battery pack is expanded, enabling the battery pack to charge and release more power, meeting the user's power consumption needs, improving the charging and discharging availability of the battery pack, and enhancing the user experience.

[0051] Among them, the backup power mode refers to the operating mode in which the battery pack provides power support as a backup power source when the main power supply fails or needs to be suspended. Correspondingly, the non - backup power mode refers to the operating mode in which the battery pack provides power support for the daily operation of the device.

[0052] When the battery pack is in the backup power mode, the battery pack needs to be prepared to provide power support for the load when needed. In this case, by controlling the maximum allowable charge and discharge amount of the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, the operating range of the battery pack is expanded, enabling the battery pack to charge more power, effectively coping with the scenario of insufficient backup power due to insufficient SOC accuracy, ensuring that the user's power consumption needs can be met when needed, improving the charging and discharging availability of the battery pack, and enhancing the user experience.

[0053] When it is detected that the voltage change rate of the battery pack within a preset time period is less than the preset change rate or the battery pack is in the backup power mode, if the maximum allowable charge and discharge amount of the battery pack is greater than the second preset charge and discharge amount greater than the first preset charge and discharge amount, it is considered that the battery pack can charge and release more power, meeting the user's power consumption needs, and there is no need to further control the increase of the maximum allowable charge and discharge amount of the battery pack.

[0054] For the sake of easy understanding, taking the maximum allowable charge and discharge amount of the battery pack being equal to the first preset charge and discharge amount as an example, please refer to Figure 2 , Figure 2 which shows a timing diagram of the control process of a controller.

[0055] As Figure 2As shown, at the first moment t1, the maximum charge and discharge amount allowed by the battery pack is equal to the first preset charge and discharge amount Q1. At the second moment t2, when the voltage change rate of the battery pack within the preset time period is less than the preset change rate or the battery pack is in the standby power mode, the maximum charge and discharge amount allowed by the battery pack is controlled to increase to be greater than Q1.

[0056] In this embodiment, when it is detected that the voltage change rate of the battery pack within the preset time period is less than the preset change rate or the battery pack is in the standby power mode, and the maximum charge and discharge amount allowed by the battery pack is less than or equal to the first preset charge and discharge amount, the controller controls the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and controls the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount, thereby expanding the operating range of the battery pack, enabling the battery pack to charge and discharge more electricity, meeting the user's power consumption requirements, improving the charge and discharge availability of the battery pack, and enhancing the user experience.

[0057] In one implementation, controlling the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount may include: controlling the upper SOC cut-off value allowed for the battery pack to increase, and / or controlling the lower SOC cut-off value allowed for the battery pack to decrease.

[0058] Among them, the upper SOC cut-off value is a percentage, which means that during the charging process of the battery pack, when the SOC reaches the set percentage, charging automatically stops to prevent overcharging of the battery pack. The lower SOC cut-off value is also a percentage, which means that during the discharging process of the battery pack, when the SOC drops to the set percentage, discharging automatically stops or the output power of the battery pack is restricted to prevent over-discharging of the battery pack.

[0059] Controlling the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount means controlling the SOC range corresponding to the maximum charge and discharge amount allowed by the battery pack to increase, that is, the difference between the upper SOC cut-off value and the lower SOC cut-off value becomes larger, increasing to the SOC range corresponding to the second preset charge and discharge amount.

[0060] For easy understanding, please refer to Figure 3 , Figure 3 shows a schematic diagram of the maximum charge and discharge amount of a battery pack. Among them, Figure 3 the shaded part in indicates the maximum charge and discharge amount allowed by the battery pack.

[0061] As Figure 3 shown in (a) of, the SOC range corresponding to the rated charge and discharge amount of the battery pack is [0, 100%].

[0062] As Figure 3As shown in (b) therein, the SOC range corresponding to the first preset charge-discharge amount is [SOC2', SOC1'], for example, [SOC2', SOC1'] = [20%, 80%].

[0063] As Figure 3 As shown in (c) therein, after the controller controls the upper SOC cut-off value allowed for the battery pack to increase and the lower SOC cut-off value allowed for the battery pack to decrease, the SOC range corresponding to the maximum charge-discharge amount allowed for the battery pack is [SOC2, SOC1], for example, [SOC2, SOC1] = [10%, 90%].

[0064] In this embodiment, the controller can accurately control the maximum charge-discharge amount allowed for the battery pack to increase to the second preset charge-discharge amount by controlling the upper SOC cut-off value allowed for the battery pack to increase and / or controlling the lower SOC cut-off value allowed for the battery pack to decrease, and release the operating range of the battery pack, so that the battery pack can charge and discharge more electricity, meet the user's power consumption needs, improve the charge-discharge availability of the battery pack, and improve the user experience.

[0065] In another embodiment, the controller is further configured to: when the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate or the battery pack is in a non-backup power mode, and the maximum charge-discharge amount allowed for the battery pack is greater than or equal to the first preset charge-discharge amount, control the maximum charge-discharge amount allowed for the battery pack to decrease to a third preset charge-discharge amount less than the first preset charge-discharge amount, and control the charge-discharge amount of the battery pack to be less than or equal to the third preset charge-discharge amount.

[0066] If the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate, it is considered that deep charge-discharge has occurred within the preset time period, the SOC accuracy of the battery pack is relatively high, and the charge-discharge availability of the battery pack is relatively high.

[0067] When the battery pack is in a non-backup power mode, the battery pack needs to provide power support for the daily operation of the load, that is, the battery pack usually charges and discharges frequently.

[0068] In this case, by controlling the maximum charge-discharge amount allowed for the battery pack to decrease to a third preset charge-discharge amount less than the first preset charge-discharge amount, the relationship between SOC and the amount of electricity during the operation of the battery pack is closer to linear, and the change in SOC can accurately match the charged / discharged amount of electricity, further improving the user experience. At the same time, the decrease in the maximum charge-discharge amount allowed for the battery pack can improve the charge-discharge efficiency of the battery pack and protect the service life of the battery pack.

[0069] When the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate or the battery pack is in a non-backup power mode, and the maximum charge-discharge amount allowed by the battery pack is less than a third preset charge-discharge amount that is less than the first preset charge-discharge amount, it is considered that the change in the SOC of the battery pack can accurately match the charged / discharged amount, and the user experience is better, and there is no need to further control the reduction of the maximum charge-discharge amount allowed by the battery pack.

[0070] For ease of understanding, taking the maximum charge-discharge amount allowed by the battery pack being equal to the first preset charge-discharge amount as an example, please refer to Figure 4 , Figure 4 which shows a timing diagram of the control process of another controller.

[0071] As Figure 4 shown, at the first moment t1, the maximum charge-discharge amount allowed by the battery pack is equal to the first preset charge-discharge amount Q1. At the second moment t2, the voltage change rate of the battery pack within the preset time period is greater than or equal to the preset change rate or the battery pack is in a non-backup power mode, and the maximum charge-discharge amount allowed by the battery pack is controlled to decrease to less than Q1.

[0072] In this embodiment, when the voltage change rate of the battery pack within the preset time period is greater than or equal to the preset change rate or the battery pack is in a non-backup power mode, and the maximum charge-discharge amount allowed by the battery pack is greater than or equal to the first preset charge-discharge amount, the controller controls the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount that is less than the first preset charge-discharge amount, and controls the charge-discharge amount of the battery pack to be less than or equal to the third preset charge-discharge amount, so that the relationship between the SOC and the charge-discharge amount during the operation of the battery pack is closer to linear, and the change in the SOC can accurately match the charged / discharged amount, further improving the user experience. At the same time, the reduction of the maximum charge-discharge amount allowed by the battery pack can improve the charge-discharge efficiency of the battery pack and protect the service life of the battery pack.

[0073] In one implementation manner, controlling the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount that is less than the first preset charge-discharge amount may include: controlling the upper SOC cut-off value allowed for the battery pack to decrease, and / or controlling the lower SOC cut-off value allowed for the battery pack to increase.

[0074] Controlling the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount that is less than the first preset charge-discharge amount means controlling the SOC range corresponding to the maximum charge-discharge amount allowed by the battery pack to decrease, that is, the difference between the upper SOC cut-off value and the lower SOC cut-off value decreases, and decreases to the SOC range corresponding to the third preset charge-discharge amount.

[0075] For ease of understanding, please refer to Figure 5 , Figure 5 which shows a schematic diagram of the maximum charge-discharge amount of another battery pack. Among them,Figure 5 The shaded part in it indicates the maximum charge and discharge amount allowed for the battery pack.

[0076] As Figure 5 shown in (a) therein, the SOC range corresponding to the rated charge and discharge amount of the battery pack is [0, 100%].

[0077] As Figure 5 shown in (b) therein, the SOC range corresponding to the first preset charge and discharge amount is [SOC2', SOC1'], for example, [SOC2', SOC1'] = [20%, 80%].

[0078] As Figure 5 shown in (c) therein, after the controller controls the reduction of the upper cut-off value of the SOC allowed for the battery pack to be used and the increase of the lower cut-off value of the SOC allowed for the battery pack to be used, the SOC range corresponding to the maximum charge and discharge amount allowed for the battery pack is [SOC2, SOC1], for example, [SOC2, SOC1] = [30%, 70%].

[0079] In this embodiment, the controller can accurately control the maximum charge and discharge amount allowed for the battery pack to be reduced to the third preset charge and discharge amount by controlling the reduction of the upper cut-off value of the SOC allowed for the battery pack to be used and / or controlling the increase of the lower cut-off value of the SOC allowed for the battery pack to be used, so that the relationship between the SOC and the electric quantity during the operation of the battery pack is closer to linear, and the change of the SOC can accurately match the charged / discharged electric quantity, further improving the user experience. At the same time, the reduction of the maximum charge and discharge amount allowed for the battery pack can improve the charge and discharge efficiency of the battery pack and protect the service life of the battery pack.

[0080] In order to facilitate the user to directly obtain the available SOC of the battery pack, a display screen associated with the battery pack is usually set in the energy storage system. The user can directly read the current SOC of the battery pack from the display screen. The current SOC displayed on the display screen refers to the ratio of the remaining electric quantity of the battery pack at a certain moment to the maximum charge and discharge amount allowed for the battery pack. Among them, the maximum value of the current SOC is 100%, the minimum value is 0, and the maximum and minimum values do not change with the change of the maximum charge and discharge amount allowed for the battery pack.

[0081] The specific value of the current SOC is related to the upper cut-off value of the SOC and the lower cut-off value of the SOC. In one embodiment, the process of calculating the current SOC includes: calculating the difference between the internal SOC and the lower cut-off value of the SOC as the first value; calculating the ratio of the difference between the upper cut-off value of the SOC and the lower cut-off value of the SOC to the state of health of the battery SOH as the second value; calculating the ratio of the second value to the first value as the current SOC.

[0082] The calculation formula of the current SOC is:

[0083]

[0084] Among them, the internal SOC refers to the ratio of the remaining power of the battery pack at a certain moment to the rated charge and discharge capacity. SOC1 refers to the upper cut-off value of the SOC of the battery pack, and SOC2 refers to the lower cut-off value of the SOC of the battery pack.

[0085] According to the above calculation formula (1), the current SOC can be dynamically calculated when the maximum charge and discharge capacity allowed by the battery pack is different, that is, when the SOC range allowed for the battery pack to use is different.

[0086] Similarly, it can be known from the above calculation formula (1) that: during the process of controlling the change of the upper cut-off value and / or the lower cut-off value of the SOC allowed for the battery pack, if the upper cut-off value and / or the lower cut-off value of the SOC jumps, the value of the current SOC displayed on the display screen will also jump, affecting the user experience.

[0087] Thus, in one embodiment, the controller is specifically configured to: control the upper cut-off value of the SOC allowed for the battery pack to change at a first rate, and / or control the lower cut-off value of the SOC allowed for the battery pack to change at a second rate, and both the first rate and the second rate are less than the rate threshold.

[0088] In one implementation manner, controlling the upper cut-off value of the SOC allowed for the battery pack to increase, and / or controlling the lower cut-off value of the SOC allowed for the battery pack to decrease, may include: controlling the upper cut-off value of the SOC allowed for the battery pack to increase at a first rate, and / or controlling the lower cut-off value of the SOC allowed for the battery pack to decrease at a second rate. And controlling the upper cut-off value of the SOC allowed for the battery pack to decrease, and / or controlling the lower cut-off value of the SOC allowed for the battery pack to increase, may include: controlling the upper cut-off value of the SOC allowed for the battery pack to decrease at a first rate, and / or controlling the lower cut-off value of the SOC allowed for the battery pack to increase at a second rate.

[0089] In the embodiments of the present application, the specific values of the first rate, the second rate, and the rate threshold are not limited. They can be set to fixed values or can be set according to specific working conditions. The first rate and the second rate can be the same or different. Since both the first rate and the second rate are less than the rate threshold, it is considered that the upper cut-off value and / or the lower cut-off value of the SOC will not jump, nor will it cause the value of the current SOC displayed on the display screen to jump.

[0090] In this embodiment, by setting a rate threshold, a first rate, and a second rate, the controller controls the upper SOC cut-off value allowed for the battery pack to change at the first rate less than the rate threshold, and / or the lower SOC cut-off value to change at the second rate less than the rate threshold, solving the problem that the jump of the lower SOC cut-off value and the upper SOC cut-off value causes the current SOC displayed on the display screen to jump, enabling the maximum charge and discharge amount allowed for the battery pack to be adjusted without the user's awareness and improving the user experience.

[0091] In one embodiment, the method for obtaining the first rate and the second rate includes: calculating the first rate according to the change amount of the upper SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen of the energy storage system, and the current of the battery pack charge and discharge; calculating the second rate according to the change amount of the lower SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen of the energy storage system, and the current of the battery pack charge and discharge.

[0092] Wherein, the change amount δSOC1 of the upper SOC cut-off value is the difference between the upper SOC cut-off value SOC1 after the adjustment of the maximum charge and discharge amount allowed for the battery pack and the upper SOC cut-off value SOC1' before the adjustment of the maximum charge and discharge amount allowed for the battery pack; the change amount δSOC1 of the lower SOC cut-off value is the difference between the lower SOC cut-off value SOC2 after the adjustment of the maximum charge and discharge amount allowed for the battery pack and the lower SOC cut-off value SOC2' before the adjustment of the maximum charge and discharge amount allowed for the battery pack; the change amount δSOC3 of the current SOC of the battery pack displayed on the display screen is the difference between the current SOC3 displayed on the display screen after the adjustment of the maximum charge and discharge amount allowed for the battery pack and the current SOC3' displayed on the display screen before the adjustment of the maximum charge and discharge amount allowed for the battery pack.

[0093] For ease of understanding, Figure 6 a flowchart showing the internal logic of a controller is shown.

[0094] As Figure 6 shown, first, calculate δSOC3 = SOC3 - SOC3' in real time, calculate δSOC1 = SOC1 - SOC1' and δSOC2 = SOC2 - SOC2' in real time. Then, identify the current I of the battery pack charge and discharge, and calculate the first rate v1 according to the pre-established mapping relationship v1 = f(SOC1, SOC3, I) between the first rate v1, δSOC1, δSOC3, and the current I. Similarly, the second rate v2 can be calculated according to the pre-established mapping relationship v2 = f(SOC2, SOC3, I) between the second rate v2, δSOC2, δSOC3, and the current I.

[0095] After that, control the upper SOC cut-off value allowed for the battery pack to increase / decrease at the first rate v1, and / or control the lower SOC cut-off value allowed for the battery pack to decrease / increase at the second rate v2.

[0096] In this embodiment, when calculating the first rate and the second rate, the controller comprehensively considers the change amount of the upper SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen, and the current charge and discharge current of the battery pack, so that the upper SOC cut-off value changes at the calculated first rate and / or the lower SOC cut-off value changes at the calculated second rate to adapt to the current working condition of the battery pack and the change of the current SOC displayed on the display screen, solving the problem that the current SOC displayed on the display screen jumps due to the jump of the lower SOC cut-off value and the upper SOC cut-off value, enabling the maximum charge and discharge amount allowed for the battery pack to be adjusted without the user's perception and improving the user experience.

[0097] In one embodiment, the controller is specifically configured to: during the process of controlling the maximum charge and discharge amount allowed for the battery pack to increase to be greater than the first preset charge and discharge amount or controlling the maximum charge and discharge amount allowed for the battery pack to decrease to be less than the first preset charge and discharge amount, the current SOC of the battery pack displayed on the display screen of the energy storage system changes at the third rate.

[0098] It can be seen from the above calculation formula (1) that: as the upper SOC cut-off value changes at the first rate and / or the lower SOC cut-off value changes at the second rate, the current SOC displayed on the display screen changes at the third rate, and the third rate can be determined according to the first rate and the second rate.

[0099] During the process of controlling the maximum charge and discharge amount allowed for the battery pack to increase to be greater than the second preset charge and discharge amount of the first preset charge and discharge amount, the SOC range allowed for the battery pack becomes larger, and the value of the current SOC displayed on the display screen when the internal SOC of the battery pack is at the second preset charge and discharge amount is less than the value of the current SOC displayed on the display screen when the internal SOC is at the first preset charge and discharge amount. In this case, the current SOC displayed on the display screen decreases at the third rate.

[0100] In one embodiment, the change mode of the current SOC displayed on the display screen is also related to the actual scenario where the battery pack is located (including the actual charging scenario and the actual discharging scenario), and it is determined according to the actual scenario whether the current SOC displayed on the display screen decreases or increases at the third rate.

[0101] In the actual discharging scenario, the internal SOC of the battery pack will continuously decrease, and the current SOC displayed on the display screen decreases at the third rate as the internal SOC decreases.

[0102] In this case, the third rate can be a relatively large value, and the current SOC decreases at a relatively large value. The third rate is greater than the rate at which the internal SOC of the battery pack decreases during discharge, and the value of the current SOC displayed on the display screen is less than the value before the maximum charge-discharge amount allowed by the battery pack increases.

[0103] Through the above settings, in the actual discharge scenario, during the process of controlling the maximum charge-discharge amount allowed by the battery pack to increase to a second preset charge-discharge amount greater than the first preset charge-discharge amount, the current SOC displayed on the display screen can quickly indicate the available SOC after the maximum charge-discharge amount allowed by the battery pack increases. Thus, the user can obtain accurate remaining power information from the display screen, improving the user experience.

[0104] In the actual charging scenario, the internal SOC of the battery pack continuously increases, and the current SOC displayed on the display screen increases at a third rate as the internal SOC increases.

[0105] In this case, the third rate can be a relatively small value, and the current SOC increases at a relatively small value. The third rate is less than the rate at which the internal SOC of the battery pack increases during charging, and the value of the current SOC displayed on the display screen is greater than or equal to the value before the maximum charge-discharge amount allowed by the battery pack increases.

[0106] Through the above settings, in the actual charging scenario, during the process of controlling the maximum charge-discharge amount allowed by the battery pack to increase to a second preset charge-discharge amount greater than the first preset charge-discharge amount, the change in the current SOC displayed on the display screen conforms to the actual charging scenario, improving the user experience.

[0107] During the process of controlling the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount less than the first preset charge-discharge amount, the range of SOC available for the battery pack decreases. The value of the current SOC displayed on the display screen when the internal SOC is at the maximum charge-discharge amount allowed by the battery pack being the third preset charge-discharge amount is greater than the value of the current SOC displayed on the display screen when the internal SOC is at the maximum charge-discharge amount allowed by the battery pack being the first preset charge-discharge amount. In this case, the current SOC displayed on the display screen increases at a third rate.

[0108] Similarly, the current SOC displayed on the display screen decreases or increases at a third rate according to the actual scenario as follows.

[0109] In the actual charging scenario, the internal SOC of the battery pack continuously increases, and the current SOC displayed on the display screen should also increase at a third rate as the internal SOC increases.

[0110] In this case, the third rate can be a relatively large value, and the current SOC increases at a relatively large value. The third rate is greater than the rate at which the internal SOC of the battery pack increases during discharge. The value of the current SOC displayed on the display screen is greater than the value before the maximum charge-discharge amount allowed by the battery pack decreases.

[0111] Through the above settings, in an actual charging scenario, during the process of controlling the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount less than the first preset charge-discharge amount, the current SOC displayed on the display screen can quickly indicate the available SOC after the maximum charge-discharge amount allowed by the battery pack decreases. Thus, the user can obtain accurate remaining power information from the display screen, improving the user experience.

[0112] In an actual discharge scenario, the internal SOC of the battery pack continuously decreases, and the current SOC displayed on the display screen decreases at the third rate as the internal SOC decreases.

[0113] In this case, the third rate can be a relatively small value, and the current SOC decreases at a relatively small value. The third rate is less than the rate at which the internal SOC of the battery pack decreases during discharge. The value of the current SOC displayed on the display screen is less than or equal to the value before the maximum charge-discharge amount allowed by the battery pack increases.

[0114] Through the above settings, in an actual discharge scenario, during the process of controlling the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount less than the first preset charge-discharge amount, the change in the current SOC displayed on the display screen conforms to the actual charging scenario, improving the user experience.

[0115] In this embodiment, during the process of controlling the maximum charge-discharge amount allowed by the battery pack to increase to a second preset charge-discharge amount greater than the first preset charge-discharge amount or controlling the maximum charge-discharge amount allowed by the battery pack to decrease to a third preset charge-discharge amount less than the first preset charge-discharge amount, the controller controls the current SOC of the battery pack displayed on the display screen to change at the third rate, so that the current SOC displayed on the display screen changes with the change of the maximum charge-discharge amount allowed by the battery pack. The user can directly obtain the SOC after the change of the maximum charge-discharge amount allowed by the battery pack from the display screen. At the same time, the current SOC changes at the third rate, avoiding the occurrence of the phenomenon of the current SOC jumping on the display screen, improving the user experience.

[0116] In one embodiment, the controller is specifically configured to: in response to a user configuration operation, control the lower SOC cut-off value allowed for the battery pack to be the lower SOC cut-off value indicated by the user configuration operation and the upper SOC cut-off value allowed for the battery pack to be the upper SOC cut-off value indicated by the user configuration operation.

[0117] In the embodiments of the present application, the specific content of the user configuration operation is not limited. For example, it can be that the user inputs an instruction, or it can be the SOC upper limit cut-off value and the SOC lower limit cut-off value input by the user by clicking on the corresponding position in the display screen, etc.

[0118] In some embodiments, the SOC upper limit cut-off value and the SOC lower limit cut-off value configured by the user configuration operation can be the SOC upper limit cut-off value and the SOC lower limit cut-off value corresponding to the first preset charge and discharge amount, or can be the SOC upper limit cut-off value and the SOC lower limit cut-off value corresponding to the charge and discharge amount after adjusting the maximum charge and discharge amount allowed by the battery pack.

[0119] In this embodiment, the user can set the SOC lower limit cut-off value and the SOC upper limit cut-off value allowed for the battery pack through the user configuration operation, so that the maximum charge and discharge amount allowed by the battery pack can meet the user's charge and discharge requirements, improving the user experience.

[0120] To facilitate understanding of the technical solution provided by the embodiments of the present application, please refer to Figure 7 , Figure 7 which shows a schematic diagram of a controller 102. The controller 102 includes a current SOC dynamic calculation module, a calibration recognition module, an SOC range dynamic switching module, and an SOC range switching slow change strategy module.

[0121] The current SOC dynamic calculation module is used to calculate the current SOC displayed on the display screen within the SOC range allowed for the current battery pack.

[0122] The calibration recognition module is used to continuously judge whether the voltage change rate of the battery pack within a preset time period is less than a preset change rate and whether it is in a non-backup power mode.

[0123] The SOC range dynamic switching module is used to dynamically adjust the SOC upper limit cut-off value and the SOC lower limit cut-off value according to the detection result of the calibration recognition module.

[0124] The SOC range switching slow change strategy module is used to control the change of the SOC upper limit cut-off value and the SOC lower limit cut-off value according to the slow change strategy, that is, calculate the first rate and the second rate, and control the change of the SOC upper limit cut-off value and the SOC lower limit cut-off value according to the first rate and the second rate.

[0125] Please refer to Figure 8 , Figure 8 which shows a flowchart of the internal logic of another controller.

[0126] As Figure 8 shown, first, execute S801, and judge whether the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate.

[0127] If the voltage change rate of the battery pack within a preset time period is less than a preset change rate, execute S802 to determine whether the SOC range of the battery pack is within a wide SOC range.

[0128] Among them, the wide SOC range indicates that the maximum charge and discharge amount allowed by the battery pack is a second preset charge and discharge amount greater than the first preset charge and discharge amount.

[0129] If the SOC range of the battery pack is within the wide SOC range, execute S803 to calculate the current SOC.

[0130] If the SOC range of the battery pack is not within the wide SOC range, execute S804 to adjust the SOC range to the wide SOC range according to the slow change strategy, and then execute S803.

[0131] If the voltage change rate of the battery pack within a preset time period is greater than or equal to the preset change rate, execute S805 to determine whether the battery pack is in a non-backup power mode.

[0132] If the battery pack is not in the non-backup power mode, execute S802.

[0133] If the battery pack is in the non-backup power mode, execute S806 to determine whether the SOC range of the battery pack is within a narrow SOC range.

[0134] Among them, the narrow SOC range indicates that the maximum charge and discharge amount allowed by the battery pack is a third preset charge and discharge amount less than the first preset charge and discharge amount.

[0135] If the SOC range of the battery pack is within the narrow SOC range, execute S803.

[0136] If the SOC range of the battery pack is not within the narrow SOC range, execute S807 to adjust the SOC range to the narrow SOC range according to the slow change strategy, and then execute S803.

[0137] In another embodiment of the embodiments of the present application, a control method for charging and discharging a battery pack is further provided for an energy storage system. The energy storage system includes a battery pack and a controller, and the control method is executed by the controller.

[0138] Among them, during the operation of the battery pack, when the voltage change rate of the battery pack within a preset time period is less than the preset change rate or in the backup power mode, and the maximum charge and discharge amount allowed by the battery pack is less than or equal to the first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to increase to be greater than the first preset charge and discharge amount.

[0139] In one embodiment, when the voltage change rate of the battery pack within a preset time period is greater than or equal to a preset change rate or the battery pack is in a non-backup power mode, and the maximum charge-discharge amount allowed by the battery pack is greater than or equal to a first preset charge-discharge amount, control the maximum charge-discharge amount allowed by the battery pack to decrease to be less than the first preset charge-discharge amount.

[0140] It can be understood that all relevant contents involved in the above method embodiments can be cited in the embodiments of this control method, and the embodiments of this application will not be elaborated herein.

[0141] Finally, it should be noted that the above are only specific embodiments of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

1. An energy storage system, characterized in that, The energy storage system includes a battery pack and a controller, and the controller is used to control the charge and discharge of the battery pack. Specifically, the controller is configured to: During the operation of the battery pack, when the voltage change rate of the battery pack within a preset time period is less than a preset change rate or the battery pack is in the standby power mode, and the maximum allowable charge and discharge amount of the battery pack is less than or equal to a first preset charge and discharge amount, control the maximum allowable charge and discharge amount of the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount.

2. The energy storage system according to claim 1, characterized in that, The controller is further configured to: When the voltage change rate of the battery pack within a preset time period is greater than or equal to the preset change rate and the battery pack is not in the standby power mode, and the maximum allowable charge and discharge amount of the battery pack is greater than or equal to the first preset charge and discharge amount, control the maximum allowable charge and discharge amount of the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the third preset charge and discharge amount.

3. The energy storage system according to claim 1 or 2, characterized in that, The control of increasing the maximum allowable charge and discharge amount of the battery pack to a second preset charge and discharge amount greater than the first preset charge and discharge amount includes: Controlling the upper SOC cut-off value allowed to be used by the battery pack to increase, and / or controlling the lower SOC cut-off value allowed to be used by the battery pack to decrease.

4. The energy storage system according to claim 3, wherein The control of decreasing the maximum allowable charge and discharge amount of the battery pack to a third preset charge and discharge amount less than the first preset charge and discharge amount includes: Controlling the upper SOC cut-off value allowed to be used by the battery pack to decrease, and / or controlling the lower SOC cut-off value allowed to be used by the battery pack to increase.

5. The energy storage system according to claim 3 or 4, characterized in that, Specifically, the controller is configured to: Control the upper SOC cut-off value allowed to be used by the battery pack to change at a first rate, and / or control the lower SOC cut-off value allowed to be used by the battery pack to change at a second rate, where both the first rate and the second rate are less than a rate threshold.

6. The energy storage system according to claim 5, characterized in that Specifically, the controller is configured to: Calculate the first rate based on the change amount of the upper SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen of the energy storage system, and the current of the battery pack's charge and discharge. Calculate the second rate based on the change amount of the lower SOC cut-off value, the change amount of the current SOC of the battery pack displayed on the display screen of the energy storage system, and the current of the battery pack's charge and discharge.

7. The energy storage system according to any one of claims 1-6, characterized in that Specifically, the controller is configured to: During the process of controlling the maximum allowable charge and discharge amount of the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount or controlling the maximum allowable charge and discharge amount of the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, the current SOC of the battery pack displayed on the display screen of the energy storage system changes at a third rate.

8. The energy storage system according to claim 3 or 4, characterized in that, Specifically, the controller is configured to: In response to a user configuration operation, control the lower SOC cut-off value allowed for use by the battery pack to be the lower SOC cut-off value indicated by the user configuration operation and the upper SOC cut-off value allowed for use by the battery pack to be the upper SOC cut-off value indicated by the user configuration operation.

9. A control method for charging and discharging a battery pack, characterized in that, For an energy storage system, the energy storage system includes a battery pack and a controller, and the control method is executed by the controller, and includes: During the operation of the battery pack, when the voltage change rate of the battery pack within a preset time period is less than a preset change rate or in a standby power mode, and the maximum charge and discharge amount allowed by the battery pack is less than or equal to a first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to increase to a second preset charge and discharge amount greater than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the second preset charge and discharge amount.

10. The control method according to claim 9, characterized in that, The method further includes: When the voltage change rate of the battery pack within a preset time period is greater than or equal to the preset change rate or in a non-standby power mode, and the maximum charge and discharge amount allowed by the battery pack is greater than or equal to the first preset charge and discharge amount, control the maximum charge and discharge amount allowed by the battery pack to decrease to a third preset charge and discharge amount less than the first preset charge and discharge amount, and control the charge and discharge amount of the battery pack to be less than or equal to the third preset charge and discharge amount.

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