CN112865264A - Method for controlling energy storage device, power supply system and power utilization device - Google Patents
Method for controlling energy storage device, power supply system and power utilization device Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0068—Battery or charger load switching, e.g. concurrent charging and load supply
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Abstract
The embodiment of the invention relates to the technical field of energy storage, and discloses a method for controlling an energy storage device, the energy storage device, a power supply system and a power utilization device, wherein the energy storage device comprises a battery pack array, the battery pack array comprises at least two battery packs connected in parallel, when a single battery pack has a fault, only the fault battery pack is cut off when the current charge state value of the battery pack array is in the charge state range (namely the preset threshold interval) corresponding to the typical operation working condition, on one hand, the rest battery packs in the battery pack array can be continuously used, the fault influence range can be reduced, on the other hand, the charge state of the fault battery pack is in the charge state range (namely the preset threshold interval) corresponding to the typical operation working condition, and the charge state of the rest battery packs can reach the charge state of the fault battery pack again in a short time after the fault battery pack recovers to be normal, therefore, the failed battery packs after being recovered to be normal can be smoothly combined in a short time.
Description
Technical Field
The embodiment of the invention relates to the technical field of energy storage, in particular to a method for controlling an energy storage device, the energy storage device, a power supply system and a power utilization device.
Background
The energy storage device adopts a battery as an electric energy storage carrier, stores electric energy within a certain time and supplies the electric energy within a certain time, and is widely applied to application scenes that terminal users are families or individuals, such as low-voltage household storage, high-voltage household storage, small-sized industrial and commercial storage and the like. The energy storage device mainly includes a plurality of battery packs (Module/Pack/Rack), a Battery Management System (BMS), a power conversion unit (PCS), and the like, wherein the plurality of battery packs are connected to form a battery Pack array.
At present, when a single battery pack has a fault alarm, two fault processing modes exist in the industry:
(1) the BMS controls all the battery packs to be electrically disconnected with the PCS, namely all the battery packs are shut down, the battery packs are waited for the maintenance of the fault battery packs, and the battery packs are electrified and started again after the fault is cleared, however, the mode can cause a larger fault influence range;
(2) the BMS is used for controlling the fault battery pack to be electrically disconnected with the PCS, namely, the fault battery pack is only shut down, the rest battery packs normally operate, after the fault is cleared, the fault battery pack is influenced by working conditions, parallel operation environments and the like, and the risk that the parallel operation cannot be carried out again for a long time after the fault battery is recovered to be normal exists.
It can be seen that both of the above-mentioned processing methods have disadvantages, and how to overcome the disadvantages is a technical problem that needs to be solved urgently by those skilled in the art.
Disclosure of Invention
The technical problem mainly solved by the embodiments of the present invention is to provide a method for controlling an energy storage device, a power supply system and a power utilization device, which can reduce the fault influence range and enable the recovered fault batteries to be smoothly parallel when a single battery pack has a fault.
In order to solve the above technical problem, in a first aspect, an embodiment of the present invention provides a method for controlling an energy storage device, where the energy storage device includes a battery pack array and a power conversion unit, the battery pack array includes at least two battery packs connected in parallel, each battery pack is electrically connected to the power conversion unit, and the method includes:
when a fault battery pack occurs in the battery pack array, acquiring a current state of charge value of the battery pack array, wherein the fault battery pack is a battery pack with a fault in any one of the battery pack arrays;
and if the current state of charge value of the battery pack array is within a preset threshold interval, controlling the fault battery pack and the power conversion unit to be electrically disconnected.
In some embodiments, the method further comprises:
and if the current state of charge value of the battery pack array is outside the preset threshold interval, controlling the battery pack array and the power conversion unit to be electrically disconnected.
In some embodiments, the method further comprises:
and after the fault battery pack is recovered to be normal, controlling the fault battery pack and the battery pack array to be electrically connected with the power conversion unit.
In some embodiments, the method further comprises:
under the condition that only a fault battery pack is disconnected, after the fault battery pack recovers to be normal, judging whether the absolute value of the difference value between the state of charge value of the fault battery pack which recovers to be normal and the state of charge value of the current battery pack array is smaller than a preset value or not;
and if so, controlling the failed battery pack to be electrically reconnected with the power conversion unit.
In some embodiments, the method further comprises:
acquiring a plurality of historical state of charge values of the battery pack array within a preset time period before the fault battery pack breaks down, wherein the number of the historical state of charge values is at least two;
and determining the upper limit and the lower limit of the preset threshold interval according to the plurality of historical state of charge values.
In some embodiments, the determining the upper limit and the lower limit of the preset threshold interval according to the plurality of historical state of charge values includes:
dividing the plurality of historical state of charge values into a plurality of state of charge intervals according to time;
acquiring a minimum state of charge value in each state of charge interval to obtain a minimum state of charge value set, and determining a lower limit of the preset threshold interval according to the minimum state of charge value set;
and acquiring the maximum state of charge value in each state of charge interval to obtain a maximum state of charge value set, and determining the upper limit of the preset threshold interval according to the maximum state of charge value set.
In some embodiments, the determining a lower limit of the preset threshold interval according to the minimum set of state of charge values includes:
and determining the lower limit of the preset threshold interval as the secondary minimum value in the minimum state of charge value set.
In some embodiments, the determining a lower limit of the preset threshold interval according to the minimum set of state of charge values includes:
and determining the lower limit of the preset threshold interval as the average value of the charge state values in the minimum charge state value set.
In some embodiments, said determining an upper limit of said preset threshold interval according to said set of maximum state of charge values comprises:
and determining the upper limit of the preset threshold interval as the second maximum value in the maximum charge state value set.
In some embodiments, said determining an upper limit of said preset threshold interval according to said set of maximum state of charge values comprises:
and determining the upper limit of the preset threshold interval as the average value of the charge state values in the maximum charge state value set.
In some embodiments, the obtaining the current state of charge value of the battery pack array includes:
acquiring the current state of charge value of each battery pack in the battery pack array;
and determining the current state of charge value of the battery pack array according to the current state of charge value of each battery pack in the battery pack array.
In some embodiments, the determining the current state of charge value of the battery pack array according to the current state of charge value of each battery pack in the battery pack array includes:
and determining the current state of charge value of the battery pack array according to the current state of charge value of the fault battery pack and the current state of charge value of at least one normally working battery pack in the battery pack array.
In order to solve the above technical problem, in a second aspect, an embodiment of the present invention provides an energy storage device, including: the battery pack comprises a battery pack array, a power conversion unit and a control management unit, wherein the battery pack array comprises at least two battery packs connected in parallel, each battery pack is electrically connected with the power conversion unit and the control management unit respectively, and the control management unit is used for executing the method of the first aspect.
In order to solve the above technical problem, in a third aspect, an embodiment of the present invention provides a power supply system, including a power supply device and the energy storage device as described in the second aspect, where the power supply device is electrically connected to the storage device.
In order to solve the above technical problem, in a fourth aspect, an embodiment of the present invention provides an electrical device, including a load and the energy storage device according to the second aspect, where the energy storage device is configured to supply power to the load.
The embodiment of the invention has the following beneficial effects: different from the situation in the prior art, the method for controlling a storage device provided in the embodiment of the present invention includes that the storage device includes a battery pack array and a power conversion unit, the battery pack array includes at least two parallel battery packs, each battery pack is electrically connected to the power conversion unit to implement power supply and charging, when a faulty battery pack occurs in the battery pack array, the current state of charge value of the battery pack array is obtained, and if the current state of charge value of the battery pack array is within a preset threshold interval, the faulty battery pack and the power conversion unit are controlled to be electrically disconnected. Wherein the preset threshold interval reflects the range of the state of charge of the battery pack array under the typical operating condition, therefore, when a single battery pack has a fault, only the fault battery pack is cut off when the current state of charge value of the battery pack array is within the state of charge range (namely within the preset threshold interval) corresponding to the typical operation condition, on one hand, the rest battery packs in the battery pack array can be continuously used, the fault influence range can be reduced, on the other hand, the state of charge of the fault battery pack is within the state of charge range (namely within the preset threshold interval) corresponding to the typical operation condition, when the fault battery pack is recovered to be normal, the fault battery pack needs to be put into operation again, the charge states of the rest battery packs can reach the charge state of the fault battery pack again in a short time, and therefore the fault battery pack recovered to be normal can be smoothly combined in a short time.
Drawings
One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.
Fig. 1 is a schematic structural diagram of an energy storage device according to an embodiment of the present disclosure;
fig. 2 is a method for controlling an energy storage device according to an embodiment of the present application;
fig. 3 is a method for controlling an energy storage device according to another embodiment of the present application;
FIG. 4 illustrates a method for controlling an energy storage device according to another embodiment of the present disclosure;
FIG. 5 illustrates a method for controlling an energy storage device according to another embodiment of the present application;
FIG. 6 is a method for controlling an energy storage device according to another embodiment of the present application;
fig. 7 is a schematic view of a sub-flow of step S28 in the method shown in fig. 6.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It should be noted that, if not conflicted, the various features of the embodiments of the invention may be combined with each other within the scope of protection of the present application. Additionally, while functional block divisions are performed in apparatus schematics, with logical sequences shown in flowcharts, in some cases, steps shown or described may be performed in sequences other than block divisions in apparatus or flowcharts. Further, the terms "first," "second," "third," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 1, the energy storage device generally mainly includes a Power Conversion System (PCS), a Battery pack array, and a Battery Management System (BMS). The battery pack array comprises at least two battery packs connected in parallel, one battery pack is electrically connected with the power conversion unit through a high-voltage box contactor (KM), and the whole battery pack array is electrically connected with the power conversion unit through a circuit breaker. Therefore, the single battery pack can be electrically connected or disconnected with the power conversion unit through the corresponding high-voltage box contactor, and the whole battery pack array can be electrically connected or switched to be electrically connected with the power conversion unit through the circuit breaker.
The battery pack is generally formed by assembling a plurality of battery packs, and the battery packs are formed by assembling a plurality of single batteries, and it is understood that the single batteries are the most basic elements forming the battery packs and can generally provide a voltage of between 3V and 4V, so that the battery packs are formed by assembling a plurality of single batteries into a single physical module and can provide higher voltage and capacity, and the battery pack is formed by assembling a plurality of battery packs and can provide higher voltage and capacity.
The power conversion unit (PCS) mainly comprises a power conversion part and a controller and is used for realizing grid connection of a battery pack in the energy storage device. The Battery Management System (BMS) is configured to monitor in real time indicators in each battery pack related to whether the energy storage device is normal (including but not limited to various indicators such as voltage, current, and communication conditions), so that the battery pack that may affect the normal operation of the entire energy storage device can be found in real time.
The BMS includes a Master Battery Management Unit (MBMU) and a plurality of Slave Battery Management Units (SBMUs) corresponding to the number of Battery packs, each of the SBMUs is generally configured with an SBMU, each of the SBMUs is respectively connected to the MBMU, and the MBMU is generally connected to the PCS through a Controller Area Network (CAN) bus. The SBMU is used for collecting, monitoring and managing state information (voltage, temperature, current, capacity and the like) of the battery packs managed by the SBMU, reporting monitoring results to the MBMU, and the MBMU realizes real-time monitoring of states of the battery packs in the energy storage device.
Specifically, the MBMU has analysis and diagnosis functions of voltage equalization, battery pack protection, thermal management, battery performance, and the like, obtains battery parameters such as diagnosis of current capacity or remaining capacity (SOC) of a single battery pack, diagnosis of state of health (SOH) of a single battery pack, battery pack state evaluation, and estimation of sustainable discharge time in a current state during discharge from state information of each battery pack reported by each SBMU through an existing analysis and diagnosis model, and thus, the MBMU can determine whether each battery pack is faulty according to the battery parameters, that is, whether a faulty battery pack occurs in a battery pack array.
It is understood that, in some embodiments, each SBMU may also have the same function as the MBMU, that is, each SBMU may obtain corresponding battery parameters according to the state information of the corresponding battery pack through the existing analysis and diagnosis model, and then determine whether the corresponding battery pack is faulty according to the battery parameters. For example, when one of the battery parameters of a certain battery pack is not within a preset normal range, it is determined that the battery pack is out of order.
Fig. 2 is a flowchart illustrating a method for controlling an energy storage device according to an embodiment of the present invention, where the method may be specifically executed by the BMS in the above-described embodiment, and more specifically, may be executed by the SBMU. As shown in fig. 2, the method S20 includes, but is not limited to, the following steps:
s21: and when a fault battery pack occurs in the battery pack array, acquiring the current state of charge value of the battery pack array, wherein the fault battery pack is any battery pack with a fault in the battery pack array.
S22: and if the current state of charge value of the battery pack array is within a preset threshold interval, controlling the fault battery pack and the power conversion unit to be electrically disconnected.
When any battery pack 1# in the battery pack array fails, namely, a failed battery pack occurs in the battery pack array. The method comprises the steps that the SBMU based on each battery pack collects, monitors and manages state information (including but not limited to voltage, temperature, current, capacity and the like) of the battery pack managed by the SBMU, monitoring results are reported to the MBMU, and the MBMU monitors the state of each battery pack in the energy storage device in real time, so that when the state information of the battery pack 1# is monitored to be abnormal, the MBMU can analyze and diagnose that the battery pack 1# has faults according to the state information and is a fault battery pack. It can be understood that, in some embodiments, the SBMU may also determine the fault state of the battery pack according to the monitored state information, and when it is determined that the battery pack is faulty, that is, a faulty battery pack occurs, the SBMU reports the fault information of the battery pack to the MBMU in real time to notify that the battery pack is faulty.
It is understood that, for those skilled in the art, the specific implementation manner of the MBMU or the SBMU determining whether the battery pack fails according to the monitored status information of the battery packs is the prior art, and will not be described in detail herein.
And when a fault battery pack occurs, acquiring the current state of charge value of the battery pack array, wherein the current state of charge value refers to the corresponding state of charge value at the moment when the fault battery pack occurs. It is understood that the State of Charge (SOC) is a ratio reflecting the remaining capacity to the capacity at full Charge, and thus the current SOC of the battery pack array can intuitively reflect how much remaining available capacity the battery pack array has.
The battery pack array is formed by connecting at least two battery packs in parallel, so that the current state of charge value of each battery pack in the battery pack array can be acquired, and then the current state of charge value of the battery pack array is determined according to the current state of charge value of each battery pack. In some embodiments, the average of the current state of charge values of each battery pack may be used as the current state of charge value for the array of battery packs.
It can be understood that, the current state of charge value of each battery pack in the battery pack array can be obtained by acquiring parameters such as voltage, current and internal resistance of each battery pack and by combining with the existing estimation method. The existing estimation method can be an ampere-hour integral SOC calculation method, an internal resistance SOC calculation method, a fuzzy logic method or a fusion algorithm and the like.
In some embodiments, determining the current state of charge value of the battery pack array according to the current state of charge value of each battery pack in the battery pack array may specifically include:
and determining the current state of charge value of the battery pack array according to the current state of charge value of the fault battery pack and the current state of charge value of at least one normally working battery pack in the battery pack array.
In this embodiment, the current charge of the failed battery pack may be based onState value x0And the current state of charge values x of 10 normally working battery packs in the battery pack array1-x10And determining the current state of charge value of the battery pack array. For example, the current state of charge value of the battery pack array is determined to be x0-x10Average, median, weighted average, etc. Because each single battery pack used for determining the current state of charge value of the battery pack array comprises the fault battery pack, the current state of charge value of the battery pack array is specifically related to the current state of charge value of the fault battery pack. Therefore, the state of charge value of the fault battery after the normal recovery is closer to the state of charge value of the battery pack, so that mutual charging circulation caused by overlarge difference of the state of charge values of the battery pack after the normal recovery and each residual battery pack in the battery pack array can be avoided, and the battery pack array is more stable.
In step S22, after the current state of charge value of the battery pack array is obtained, the current state of charge value of the battery pack array is compared with a preset threshold interval. The preset threshold interval reflects the range of the state of charge of the battery pack array under the typical operation condition. It can be understood that the state of charge value of the battery pack array is continuously changed along with the operation of the battery pack array, the state of charge value of the battery pack array is increased when the battery pack array is in a charging state, and the state of charge value of the battery pack array is decreased when the battery pack array is in a discharging state, but generally speaking, the state of charge value of the battery pack array which is often in operation is within a range (a preset threshold interval), that is, the probability of being within the preset threshold interval is higher, which is called a typical operation condition.
If the current state of charge value of the battery pack array is within the preset threshold interval, the battery pack array is currently in the typical operation condition, and subsequently, after the fault battery pack is recovered to be normal, the battery pack array is still approximately in the typical operation condition, and the state of charge of the rest battery packs can reach the state of charge of the fault battery pack again in a short time, so that the fault battery pack recovered to be normal can be smoothly connected in a short time.
Therefore, when a single battery pack breaks down, only the broken battery pack is cut off when the battery pack array is under a typical operation condition, on one hand, the charge state of the broken battery pack is in the charge state range corresponding to the typical operation condition (namely, in a preset threshold value interval), and when the broken battery pack recovers to be normal, the battery pack needs to be put in again, and the charge states of the remaining battery packs can reach the charge state of the broken battery pack again in a short time, so that the broken battery pack which recovers to be normal can be smoothly added into the battery pack array (parallel operation), circulation current cannot be generated among the battery packs due to overlarge charge state value difference, on the other hand, only the broken battery pack is cut off, the remaining batteries in the battery pack array can be continuously used, and the fault influence range can be reduced.
In this embodiment, when a faulty battery pack occurs in the battery pack array, the current state of charge value of the battery pack array is obtained, and if the current state of charge value of the battery pack array is within a preset threshold interval, the faulty battery pack and the power conversion unit are controlled to be electrically disconnected. Wherein the preset threshold interval reflects the range of the state of charge of the battery pack array under the typical operating condition, therefore, when a single battery pack has a fault, only the fault battery pack is cut off when the current state of charge value of the battery pack array is within the state of charge range (namely within the preset threshold interval) corresponding to the typical operation condition, on one hand, the rest battery packs in the battery pack array can be continuously used, the fault influence range can be reduced, on the other hand, the state of charge of the fault battery pack is within the state of charge range (namely within the preset threshold interval) corresponding to the typical operation condition, when the fault battery pack is recovered to be normal, the fault battery pack needs to be put into operation again, the charge states of the rest battery packs can reach the charge state of the fault battery pack again in a short time, and therefore the fault battery pack recovered to be normal can be smoothly combined in a short time. .
In some embodiments, referring to fig. 3, the method S20 further includes:
s23: and if the current state of charge value of the battery pack array is outside the preset threshold interval, controlling the battery pack array and the power conversion unit to be electrically disconnected.
If the current state of charge value of the battery pack array is outside the preset threshold interval, it indicates that the battery pack array is not in the typical operation condition currently, that is, in the atypical operation condition with a low probability, and since the probability of the atypical operation condition is low, subsequently, after the failed battery pack recovers to be normal, the battery pack array is not in the atypical operation condition at a high probability, so that the difference between the state of charge values of the failed battery pack after recovering to be normal and the other battery packs in the battery pack array is high at a high probability. If the battery pack is in a normal state, the power conversion unit is connected with the battery pack in a non-normal state, and the power conversion unit is connected with the battery pack in a non-normal state.
Therefore, under the atypical operation working condition, the whole battery pack array and the power conversion unit are controlled to be disconnected, namely, the whole battery pack array is cut off, so that the problem that the normal failed battery packs cannot be normally connected due to overlarge difference of the charge state values after the normal operation is recovered is solved. That is, after the faulty battery pack is recovered to normal, it is equivalent to restart the whole battery pack array, and the difference of the state of charge between the battery packs is not large.
In this embodiment, under an atypical operation condition, the whole battery pack array and the power conversion unit are controlled to be electrically disconnected, that is, the whole battery pack array is cut off, so as to avoid the problem that the failed battery pack after being recovered to be normal cannot be normally connected due to the overlarge charge state value difference.
In some embodiments, referring to fig. 4, the method S20 further includes:
s24: and after the fault battery pack is recovered to be normal, controlling the fault battery pack and the battery pack array to be electrically connected with the power conversion unit.
Under the condition that only the fault battery pack is removed, after the fault battery pack is recovered to be normal, the SOC (state of charge) of the battery pack array is approximately in the SOC range corresponding to the typical operation condition, namely, the battery pack is in the typical operation condition, the fault battery pack is controlled to be electrically connected with the power conversion unit, and the fault battery pack recovered to be normal can be normally connected in a short time to participate in work, so that the voltage of the battery pack array can meet the requirement.
Under the condition that the battery pack array is integrally cut off, after the fault battery pack is recovered to be normal, the battery pack array is controlled to be electrically connected with the power conversion unit, namely, the battery pack array is restarted, so that the fault influence range is reduced as far as possible in time.
In some embodiments, referring to fig. 5, the method S20 further includes:
s25: under the condition that only the fault battery pack is disconnected, after the fault battery pack recovers to be normal, whether the absolute value of the difference value between the state of charge value of the fault battery pack which recovers to be normal and the state of charge value of the current battery pack array is smaller than a preset value is judged, and if yes, the step S26 is executed.
S26: and controlling the failed battery pack to be electrically reconnected with the power conversion unit.
Under the condition of only disconnecting the fault battery pack, namely under the condition of typical operation conditions, after the fault battery pack recovers to be normal, in order to further ensure that the fault battery pack can meet the parallel operation requirement, before parallel operation, firstly, the absolute value of the difference value between the state of charge value of the fault battery pack recovering to be normal and the state of charge value of the current battery pack array is determined to be smaller than a preset value, the fault battery pack is controlled to be electrically connected with the power conversion unit again, namely, the normal fault battery pack is arranged to be recovered to be parallel operated under the condition that the difference of the state of charge values between the fault battery pack and the current battery pack array is not more than the preset value, and circulation current cannot occur between the fault battery pack and other battery packs in the battery pack array due to overlarge difference of the state of charge values. When the absolute value of the difference between the two is greater than or equal to the preset value, the state of charge value of the fault battery pack after being recovered to be normal is required to be adjusted to be smaller than the preset value, and the fault battery pack after being recovered to be normal is added into the battery pack array which is in operation.
It is understood that the preset value is an empirical value set by a person, and can be set by a person skilled in the art according to actual needs.
In this embodiment, under a typical operation condition, although after a subsequent failed battery pack is recovered to be normal, the battery pack array is still approximately in the typical operation condition, and the difference between the state of charge values of the failed battery pack after being recovered to be normal and the state of charge values of other battery packs is approximately small, in order to further ensure that the failed battery pack after being recovered to be normal can meet a normal parallel operation condition, before parallel operation, the state of charge value of the failed battery pack after being recovered to be normal is evaluated, and when the state of charge value is smaller than a preset value, parallel operation is performed, so as to further avoid the problem of circulation current between the battery packs.
It will be appreciated that the predetermined threshold interval reflects a range of states of charge of the battery pack array under typical operating conditions. In some embodiments, the preset threshold interval may be an empirical value set by a person, and may be set by a person skilled in the art according to actual situations.
In order to obtain a preset threshold interval capable of accurately reflecting the operation condition of the battery pack array, so as to improve the accuracy of normal parallel operation of the failed battery packs after subsequent recovery, in some embodiments, referring to fig. 6, the method S20 further includes:
s27: and acquiring a plurality of historical state of charge values of the battery pack array within a preset time period before the fault battery pack breaks down, wherein the number of the historical state of charge values is at least two.
S28: and determining the upper limit and the lower limit of the preset threshold interval according to the plurality of historical state of charge values.
For example, when a fault battery pack fails at time T, at least two historical state of charge values of the battery pack array in a preset time period N × D are obtained, that is, at least two historical state of charge values of the battery pack array in a [ T-N × D, T ] period are obtained.
Therefore, the upper limit and the lower limit of the preset threshold interval are determined according to the plurality of historical state of charge values, for example, the plurality of historical state of charge values are sorted from small to large, the historical state of charge value corresponding to 25% percentile is determined as the lower limit, and the historical state of charge value corresponding to 75% percentile is determined as the upper limit.
In the embodiment, the upper limit and the lower limit of the preset threshold interval are determined according to a plurality of historical state of charge values of the battery pack array, so that the preset threshold interval can accurately reflect the operation condition of the battery pack array, and the accuracy of normal parallel operation of the fault battery pack after subsequent normal recovery is improved.
In some embodiments, referring to fig. 7, the step S28 specifically includes:
s281: the plurality of historical state of charge values are divided into a plurality of state of charge intervals over time.
S282: and acquiring the minimum state of charge value in each state of charge interval to obtain a minimum state of charge value set, and determining the lower limit of the preset threshold interval according to the minimum state of charge value set.
S283: and acquiring the maximum state of charge value in each state of charge interval to obtain a maximum state of charge value set, and determining the upper limit of the preset threshold interval according to the maximum state of charge value set.
The plurality of historical state of charge values are divided into a plurality of state of charge intervals over time, taking into account that the plurality of historical state of charge values are time-varying. For example, a plurality of state of charge values in the [ T-N × D, T ] period are time-divided into N intervals, and N state of charge intervals corresponding to N time intervals, such as [ T-D, T ], [ T-2D, T-D ]. the.
The minimum state of charge value in each state of charge interval is obtained, for example, the minimum value SOCmin1 of the plurality of state of charge values in the [ T-N × D, T ] time period is obtained, the minimum value SOCmin2 of the plurality of state of charge values in the [ T-2D, T-D ] time period is obtained, and the like, and the minimum value SOCmin N of the plurality of state of charge values in the [ T-N × D, T- (N-1) × D ] time period is obtained. Thus, { SOCmin1, SOCmin2.. SOCmin n } constitutes a minimum set of states of charge.
And then, determining the lower limit of the preset threshold interval according to the minimum state of charge set, so that the lower limit of the preset threshold interval is more reasonable, the interference of a small value in a special state on the lower limit of the preset threshold interval can be avoided, and the lower limit of the preset threshold interval can reflect the lowest critical value of the state of charge value under a typical operation condition.
In some embodiments, the step of determining the lower limit of the preset threshold interval according to the minimum set of state of charge values specifically includes:
and determining the lower limit of the preset threshold interval as the secondary minimum value in the minimum state of charge value set.
For example, taking N as 10 time periods before the occurrence of the fault as an example, 10 SOCmin are ordered from small to large as { SOCmin1 ', SOCmin2 ', SOCmin3 ', SOCmin4 ', SOCmin5 ', SOCmin6 ', SOCmin7 ', SOCmin8 ', SOCmin9 ', SOCmin10 ' }, where the smallest first 10%, SOCmin1 ', is infrequent. In order to make the lower limit of the preset threshold interval reflect the lowest critical value of the state of charge value under the typical operation condition, the next lowest value SOCmin 2' in the set can be used as the lower limit of the preset threshold interval.
In some embodiments, the step of determining the lower limit of the preset threshold interval according to the minimum set of state of charge values further includes:
and determining the lower limit of the preset threshold interval as the average value of the charge state values in the minimum charge state value set.
For example, taking N before occurrence of a fault as an example of 10 time periods, an average value of the state of charge values in the minimum set of state of charge values { SOCmin1, SOCmin2.... and SOCmin10} is calculated, and the average value is used as a lower limit of the preset threshold interval, so that the lower limit of the preset threshold interval can better reflect the lowest critical value of the state of charge values under the typical operating condition.
Similarly, in order to make the upper limit of the preset threshold interval more reflect the highest critical value of the soc values under the typical operating condition, in step S283, the maximum soc value in each soc interval is obtained, for example, the maximum soc cmax1 of the soc values in the [ T-N × D, T ] period is obtained, the maximum soc cmax2 of the soc values in the [ T-2D, T-D ] period is obtained, and by analogy, the maximum soc max N of the soc values in the [ T-N × D, T- (N-1) D ] period is obtained. Thus, { SOCmax1, SOCmax2.. SOCmaxN } constitutes a set of maximum states of charge.
And then, determining the upper limit of the preset threshold interval according to the maximum state of charge set, so that the upper limit of the preset threshold interval is more reasonable, the interference of a larger value in a special state to the upper limit of the preset threshold interval can be avoided, and the upper limit of the preset threshold interval can reflect the highest critical value of the state of charge value under a typical operation condition.
In some embodiments, the step of determining the upper limit of the preset threshold interval according to the maximum set of state of charge values specifically includes:
and determining the upper limit of the preset threshold interval as the second maximum value in the maximum charge state value set.
For example, taking N as 10 time periods before the occurrence of the fault as an example, 10 SOCmax are ranked from small to large as { SOCmax1 ', SOCmax2 ', SOCmax3 ', SOCmax4 ', SOCmax5 ', SOCmax6 ', SOCmax7 ', SOCmax8 ', SOCmax9 ', SOCmax10 ', where the largest last 10%, i.e., SOCmax10 ', does not occur frequently. In order to make the upper limit of the preset threshold interval reflect the highest critical value of the soc value under the typical operating condition, the sub-maximum value SOCmax 9' in the set may be used as the upper limit of the preset threshold interval.
In some embodiments, the step of determining the upper limit of the preset threshold interval according to the maximum set of state of charge values further includes:
and determining the upper limit of the preset threshold interval as the average value of the charge state values in the maximum charge state value set.
For example, taking N-10 time periods before the occurrence of the fault as an example, an average value of the state of charge values in the maximum state of charge value set { SOCmax1, SOCmax2.... and SOCmax10} is calculated, and the average value is used as an upper limit of a preset threshold interval, so that the upper limit of the preset threshold interval can better reflect the highest critical value of the state of charge values under the typical operating condition.
In the present embodiment, a plurality of historical state of charge values are divided into a plurality of state of charge intervals in time, and then, according to the plurality of state of charge intervals, a minimum state of charge value set and a maximum state of charge value set are acquired. And determining the lower limit of the preset threshold interval according to the minimum state of charge set, so that the lower limit of the preset threshold interval is more reasonable, and the interference of a small value in a special state on the lower limit of the preset threshold interval can be avoided, and the lower limit of the preset threshold interval can reflect the minimum critical value of the state of charge value under a typical operation condition. And determining the upper limit of the preset threshold interval according to the maximum state of charge set, so that the upper limit of the preset threshold interval is more reasonable, the interference of a larger value in a special state to the upper limit of the preset threshold interval can be avoided, and the upper limit of the preset threshold interval can reflect the highest critical value of the state of charge value under a typical operation condition.
To sum up, in the method for controlling an energy storage device in the embodiment of the present application, when a faulty battery pack occurs in a battery pack array, a current state of charge value of the battery pack array is obtained, and if the current state of charge value of the battery pack array is within a preset threshold interval, the faulty battery pack and a power conversion unit are controlled to be electrically disconnected. Wherein the preset threshold interval reflects the range of the state of charge of the battery pack array under the typical operating condition, therefore, when a single battery pack has a fault, only the fault battery pack is cut off when the current state of charge value of the battery pack array is within the state of charge range (namely within the preset threshold interval) corresponding to the typical operation condition, on one hand, the rest battery packs in the battery pack array can be continuously used, the fault influence range can be reduced, on the other hand, the state of charge of the fault battery pack is within the state of charge range (namely within the preset threshold interval) corresponding to the typical operation condition, when the fault battery pack is recovered to be normal, the fault battery pack needs to be put into operation again, the charge states of the rest battery packs can reach the charge state of the fault battery pack again in a short time, and therefore the fault battery pack recovered to be normal can be smoothly combined in a short time.
Another embodiment of the present application further provides an energy storage device, including a battery pack array, a power conversion unit, and a control management unit, where the battery pack array includes at least two battery packs connected in parallel, each battery pack is electrically connected to the power conversion unit and the control management unit, respectively, and the control management unit is configured to perform the method for controlling the energy storage device in any of the above method embodiments, for example, perform the method described in fig. 2 to fig. 7.
Specifically, the control management unit includes a memory and a processor, where the memory is used for storing a computer program, and the processor is used for executing the computer program stored in the memory to implement the method for controlling the energy storage device in any of the embodiments described above in the present application.
Therefore, the energy storage device can execute the method provided by the embodiment of the application, and has the corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the methods provided in the embodiments of the present application.
Another embodiment of the present application further provides a power supply system, which includes a power supply device and the energy storage device in the above embodiment, where the power supply device is electrically connected to the energy storage device. The power supply device can be a power generation device such as photovoltaic power generation. Based on the fact that the energy storage device in this embodiment has the same structure and function as the energy storage device in the above embodiment, detailed description is omitted here. Because this energy memory can reduce trouble influence scope under the condition that single battery package broke down, can also make the trouble battery after recovering normal smooth parallel operation to, make this power supply system more stable.
Another embodiment of the present application further provides an electric device, which includes a load and the energy storage device in the above embodiment, where the energy storage device is used to supply power to the load. For example, when the load is a new energy automobile, the energy storage device charges the new energy automobile. It can be understood that the energy storage device in this embodiment has the same structure and function as the energy storage device in the above embodiment, and therefore, the detailed description thereof is omitted.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a general hardware platform, and certainly can also be implemented by hardware. It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, which can be stored in a computer readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (15)
1. A method of controlling an energy storage device, the energy storage device including an array of battery packs and a power conversion unit, the array of battery packs including at least two battery packs connected in parallel, each battery pack being electrically connected to the power conversion unit, comprising:
when a fault battery pack occurs in the battery pack array, acquiring a current state of charge value of the battery pack array, wherein the fault battery pack is a battery pack with a fault in any one of the battery pack arrays;
and if the current state of charge value of the battery pack array is within a preset threshold interval, controlling the fault battery pack and the power conversion unit to be electrically disconnected.
2. The method of claim 1, further comprising:
and if the current state of charge value of the battery pack array is outside the preset threshold interval, controlling the battery pack array and the power conversion unit to be electrically disconnected.
3. The method according to claim 1 or 2, characterized in that the method further comprises:
and after the fault battery pack is recovered to be normal, controlling the fault battery pack and the battery pack array to be electrically connected with the power conversion unit.
4. The method of claim 3, further comprising:
under the condition that only a fault battery pack is disconnected, after the fault battery pack recovers to be normal, judging whether the absolute value of the difference value between the state of charge value of the fault battery pack which recovers to be normal and the state of charge value of the current battery pack array is smaller than a preset value or not;
and if so, controlling the failed battery pack to be electrically reconnected with the power conversion unit.
5. The method according to any one of claims 4, further comprising:
acquiring a plurality of historical state of charge values of the battery pack array within a preset time period before the fault battery pack breaks down, wherein the number of the historical state of charge values is at least two;
and determining the upper limit and the lower limit of the preset threshold interval according to the plurality of historical state of charge values.
6. The method of claim 5, wherein said determining an upper limit and a lower limit of said preset threshold interval from said plurality of historical state of charge values comprises:
dividing the plurality of historical state of charge values into a plurality of state of charge intervals according to time;
acquiring a minimum state of charge value in each state of charge interval to obtain a minimum state of charge value set, and determining a lower limit of the preset threshold interval according to the minimum state of charge value set;
and acquiring the maximum state of charge value in each state of charge interval to obtain a maximum state of charge value set, and determining the upper limit of the preset threshold interval according to the maximum state of charge value set.
7. The method of claim 6, wherein said determining a lower limit of said preset threshold interval from said minimum set of state of charge values comprises:
and determining the lower limit of the preset threshold interval as the secondary minimum value in the minimum state of charge value set.
8. The method of claim 6, wherein said determining a lower limit of said preset threshold interval from said minimum set of state of charge values comprises:
and determining the lower limit of the preset threshold interval as the average value of the charge state values in the minimum charge state value set.
9. The method of claim 6, wherein said determining an upper limit of said preset threshold interval from said set of maximum state of charge values comprises:
and determining the upper limit of the preset threshold interval as the second maximum value in the maximum charge state value set.
10. The method of claim 6, wherein said determining an upper limit of said preset threshold interval from said set of maximum state of charge values comprises:
and determining the upper limit of the preset threshold interval as the average value of the charge state values in the maximum charge state value set.
11. The method of claim 1 or 2, wherein said obtaining a current state of charge value of said array of battery packs comprises:
acquiring the current state of charge value of each battery pack in the battery pack array;
and determining the current state of charge value of the battery pack array according to the current state of charge value of each battery pack in the battery pack array.
12. The method of claim 11, wherein determining the current state of charge value for the array of battery packs from the current state of charge value for each battery pack in the array of battery packs comprises:
and determining the current state of charge value of the battery pack array according to the current state of charge value of the fault battery pack and the current state of charge value of at least one normally working battery pack in the battery pack array.
13. An energy storage device, comprising: the system comprises a battery pack array, a power conversion unit and a control management unit, wherein the battery pack array comprises at least two battery packs connected in parallel, each battery pack is electrically connected with the power conversion unit and the control management unit respectively, and the control management unit is used for executing the method according to any one of claims 1-12.
14. A power supply system comprising a power supply device and an energy storage device as claimed in claim 13, the power supply device being electrically connected to the storage device.
15. An electrical device comprising a load and an energy storage device as claimed in claim 13, the energy storage device being arranged to supply power to the load.
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