CN114415055A - Energy storage system and SOC estimation method thereof - Google Patents

Energy storage system and SOC estimation method thereof Download PDF

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Publication number
CN114415055A
CN114415055A CN202210308600.9A CN202210308600A CN114415055A CN 114415055 A CN114415055 A CN 114415055A CN 202210308600 A CN202210308600 A CN 202210308600A CN 114415055 A CN114415055 A CN 114415055A
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energy storage
storage battery
battery pack
type
soc
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CN114415055B (en
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周俭节
许二超
徐清清
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Sungrow Power Supply Co Ltd
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Sungrow Power Supply Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/378—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H01M10/482—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for several batteries or cells simultaneously or sequentially
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Secondary Cells (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The application provides an energy storage system and an SOC estimation method thereof. In the SOC estimation method, because the open-circuit voltage of the first type of energy storage battery pack and the SOC are in a linear relation, the SOC of the first type of energy storage battery pack is utilized to determine the working state change of the first type of energy storage battery pack, so that the working state change of the first type of energy storage battery pack is closer to the actual change, the working state change of the second type of energy storage battery pack determined according to the working state change of the first type of energy storage battery pack and the current SOC of the second type of energy storage battery pack estimated according to the working state change of the second type of energy storage battery pack is also closer to the actual value, and therefore, the estimation method can improve the SOC estimation precision of the second type of energy storage battery pack; because the lithium iron phosphate battery is contained in the second type of energy storage battery pack, the SOC estimation method of the energy storage system can improve the SOC estimation precision of the lithium iron phosphate battery.

Description

Energy storage system and SOC estimation method thereof
Technical Field
The invention relates to the technical field of secondary energy storage, in particular to an energy storage system and an SOC estimation method thereof.
Background
Since the invention of the japanese SONY corporation developed and commercialized the lithium ion secondary battery in 1991, the lithium ion battery has been rapidly developed, its application range has been increasingly expanded, market share has been increasingly improved, and particularly, with the arrival of energy crisis and the increasing environmental pressure, the market demand for the lithium ion battery has been further expanded.
At present, lithium iron phosphate batteries are widely applied to large-scale grid-connected energy storage systems. However, in practical application, the SOC of the lithium iron phosphate battery is easy to jump, so that the estimation accuracy of the SOC of the lithium iron phosphate battery is poor.
Therefore, how to improve the estimation accuracy of the SOC of the lithium iron phosphate battery is an urgent technical problem to be solved.
Disclosure of Invention
In view of this, the invention provides an energy storage system and an SOC estimation method thereof, so as to improve the estimation accuracy of the SOC of the lithium iron phosphate battery.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
one aspect of the present application provides a method for estimating SOC of an energy storage system, where a battery system in the energy storage system includes: the system comprises a first-class energy storage battery pack with an open-circuit voltage and SOC in a linear relation and a second-class energy storage battery pack with an open-circuit voltage and SOC in a nonlinear relation; the SOC estimation method is applied to any upper-level controller of the energy storage battery pack; the SOC estimation method comprises the following steps:
when two types of energy storage battery packs work simultaneously, determining the change of the working state of one type of energy storage battery pack by using the SOC of the one type of energy storage battery pack;
determining the working state change of the second type of energy storage battery pack according to the determined working state change of the first type of energy storage battery pack based on the current of each path of energy storage battery pack;
and determining the current SOC of the corresponding secondary energy storage battery pack according to the determined working state change of the secondary energy storage battery pack.
Optionally, the operating state changes, including: any one of SOC variation, remaining capacity variation, and discharge amount variation.
Optionally, when the operating state changes to SOC changes, determining a process of the operating state change of the two types of energy storage battery packs specifically includes:
determining the change of the residual capacity of the first type of energy storage battery pack according to the determined change of the SOC of the first type of energy storage battery pack;
determining the residual capacity change of the second type of energy storage battery pack according to the current of the second type of energy storage battery pack based on the mapping relation between the current of the first type of energy storage battery pack and the residual capacity change of the second type of energy storage battery pack;
and determining the SOC change of the second type of energy storage battery pack according to the residual capacity change of the second type of energy storage battery pack.
Optionally, if the number of the first type of energy storage battery pack determined by the working state change is 1 and the number of the second type of energy storage battery pack determined by the working state change is greater than 1, determining the working state change of the second type of energy storage battery pack according to the determined working state change of the first type of energy storage battery pack, including:
and respectively determining the working state changes of the two types of energy storage battery packs of different paths according to the determined working state change of the one type of energy storage battery pack.
Optionally, if the number of the first type of energy storage battery pack determined by the change of the working state is greater than 1 and the number of the second type of energy storage battery pack determined by the change of the working state is greater than 1, determining the change of the working state of the second type of energy storage battery pack according to the determined change of the working state of the first type of energy storage battery pack, including:
and respectively determining the working state change of the corresponding second type of energy storage battery pack according to the determined working state change of the first type of energy storage battery pack of each path.
Another aspect of the present application provides an energy storage system, including: a battery system, a power conversion unit, a local controller, and an energy management system; wherein:
the battery system is connected to the first side of the power conversion unit, and the second side of the power conversion unit is connected with a power grid;
the local controller is connected with the battery system, and the local controller is connected with or disconnected from the power conversion unit;
the energy management system is respectively connected with the local controller, the power conversion unit, the power grid dispatching center and the battery cell data center;
the battery system comprises an energy storage battery pack, and any superior controller of the energy storage battery pack is used for executing the SOC estimation method of the energy storage system according to any one aspect of the application.
Optionally, the battery system includes: the system comprises a battery system controller BSC, at least one path of first-class energy storage battery pack, at least one path of second-class energy storage battery pack and at least one pack level management unit; wherein:
the first sides of the group level management units are connected with the energy storage battery packs in one-to-one correspondence, and the second sides of the group level management units are used as corresponding electric power connecting ends of the battery system;
and the battery system controller is respectively connected with each group level management unit and the local controller.
Optionally, the local controller is configured to perform current distribution on each energy storage battery pack through the battery system controller; the current distribution aims to ensure that the first-class energy storage battery pack is in a working state all the time in the working process of the second-class energy storage battery pack.
Optionally, the group level management unit is a DCDC converter, and the power conversion unit includes: an energy storage converter and a transformer; wherein:
the direct current side of the energy storage converter is connected with the corresponding power connection end of the battery system, the alternating current side of the energy storage converter is connected with the primary side of the transformer, and the secondary side of the transformer is connected with the power grid.
Optionally, the local controller is further connected to the energy storage converter, and the local controller is configured to distribute current to each energy storage battery pack through the energy storage converter; the current distribution aims to ensure that the first-class energy storage battery pack is in a working state all the time in the working process of the second-class energy storage battery pack.
Optionally, the group level management unit is a DCAC converter, and the power conversion unit includes: a low voltage combiner and transformer; wherein:
the first side of the low-voltage confluence cabinet is respectively connected with the corresponding power connecting end of the battery system, the second side of the low-voltage confluence cabinet is connected with the primary side of the transformer, and the secondary side of the transformer is connected with the power grid;
each DCAC converter is connected with the local controller.
Optionally, the local controller is configured to distribute current to each energy storage battery pack through each DCAC converter; the current distribution aims to ensure that the first-class energy storage battery pack is in a working state all the time in the working process of the second-class energy storage battery pack.
Optionally, the energy storage battery pack and the pack-level management unit are respectively installed in different independent chambers;
all the energy storage battery packs are arranged in the same independent cavity, or the first type of energy storage battery pack and the second type of energy storage battery pack are respectively arranged in different independent cavities.
Optionally, the battery system further includes: the battery fire control management unit and the battery thermal management unit; wherein:
all the battery fire-fighting management units and all the battery thermal management units are connected with the battery system controller;
all the energy storage battery packs share the battery fire protection management unit and the battery thermal management unit.
Optionally, any upper controller of the energy storage battery pack is further configured to:
when the two types of energy storage battery packs work simultaneously, the first type of energy storage battery pack is used for carrying out capacity calibration and health degree identification on the second type of energy storage battery pack.
Optionally, any upper controller of the energy storage battery pack is further configured to:
and controlling the second-class energy storage battery pack to start to work after the first-class energy storage battery pack works for a preset time.
According to the technical scheme, the invention provides the SOC estimation method of the energy storage system. In the SOC estimation method, because the open-circuit voltage of the first type of energy storage battery pack and the SOC are in a linear relation, the SOC of the first type of energy storage battery pack is utilized to determine the working state change of the first type of energy storage battery pack, so that the working state change of the first type of energy storage battery pack is closer to the actual change, the working state change of the second type of energy storage battery pack determined according to the working state change of the first type of energy storage battery pack and the current SOC of the second type of energy storage battery pack estimated according to the working state change of the second type of energy storage battery pack is also closer to the actual value, and therefore, the estimation method can improve the SOC estimation precision of the second type of energy storage battery pack; because the lithium iron phosphate battery is contained in the second type of energy storage battery pack, the SOC estimation method of the energy storage system can improve the SOC estimation precision of the lithium iron phosphate battery.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a SOC estimation method of an energy storage system according to an embodiment of the present disclosure;
FIG. 2 is a schematic flow chart illustrating the process of determining the change of the operating state of the second-type energy storage battery pack when the operating state changes to SOC change;
fig. 3 and fig. 4 are schematic flow diagrams of two other implementations of a method for estimating SOC of an energy storage system according to an embodiment of the present disclosure, respectively;
fig. 5 is a schematic structural diagram of an embodiment of an energy storage system provided in an embodiment of the present application;
fig. 6 and fig. 7 are schematic structural diagrams of two embodiments of a battery system provided in an example of the present application;
fig. 8 and fig. 9 are schematic structural diagrams of two other embodiments of the energy storage system provided in the embodiment of the present application, respectively;
fig. 10 a-10 c are three schematic diagrams of the actual capacity of each energy storage battery pack in the battery system respectively;
FIG. 11a is an OCV curve of each energy storage battery pack in the battery system during charging;
fig. 11b is an OCV curve during discharge of each energy storage battery pack in the battery system.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In this application, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In order to improve estimation accuracy of the SOC of the lithium iron phosphate battery, an embodiment of the present application provides an SOC estimation method for an energy storage system, where the battery system of an energy storage unit includes: one type of energy storage battery pack in which OCV (Open Circuit Voltage) is linearly related to SOC, as shown in fig. 11a and 11b at 01 and 02, and a second type of energy storage battery pack in which OCV is non-linearly related to SOC, as shown in fig. 11a and 11b at 03.
It should be noted that fig. 11a illustrates a charging process of each energy storage battery pack, in which the SOC is shown as a horizontal axis; FIG. 11b is a diagram showing the discharging process of each energy storage battery pack, with DOD (Depth of Discharge) instead of SOC as the horizontal axis; wherein DOD is the proportion of the discharge capacity of the energy storage battery pack occupying the rated capacity of the energy storage battery pack, namely DOD =100% -SOC.
Optionally, the battery monomer in the first type of energy storage battery pack may be a ternary lithium battery, may also be a sodium ion battery, may also be a nickel-hydrogen lithium battery; in practical applications, including but not limited to, this, it is determined according to specific situations, and it is not limited herein specifically, and it is within the scope of the present application.
It should be noted that, preferably, the battery cells of one type of energy storage battery pack are ternary lithium batteries, so as to utilize the high energy density characteristic of the ternary lithium batteries to improve the energy density of the whole battery system, thereby reducing the overall volume of the battery system.
Preferably, the battery monomer in the second type of energy storage battery pack is a lithium iron phosphate battery; in practical applications, including but not limited to, this, it is determined according to specific situations, and it is not limited herein specifically, and it is within the scope of the present application.
It should be noted that, in practical application, each energy storage battery pack includes a plurality of identical battery cells, and the battery cells may be connected in series or in parallel, where the battery cells are not specifically limited and may be determined according to specific situations, and both of them are within the protection scope of the present application; moreover, how to combine a plurality of battery cells into an energy storage battery pack is a mature technology in the prior art, and is not described herein again.
The SOC estimation method is applied to any superior controller of the energy storage battery pack, the specific flow of the SOC estimation method is shown in figure 1, and the SOC estimation method specifically comprises the following steps:
and S110, when the two types of energy storage battery packs work simultaneously, determining the working state change of one type of energy storage battery pack by using the SOC of the one type of energy storage battery pack.
Optionally, the working state change may be an SOC change, a remaining capacity change, or a discharge amount change, and is not specifically limited herein and is within the protection scope of the present application.
When the operating state changes to SOC changes, an example of determining the operating state changes of one type of energy storage battery pack is:
and determining the SOC change of the first type of energy storage battery pack by using the current SOC and the last SOC of the first type of energy storage battery pack.
Specifically, the SOC change of one type of energy storage battery pack Δ SOC1= SOC12-SOC11, where SOC12 is the current SOC of one type of energy storage battery pack and SOC11 is the last SOC of one type of energy storage battery pack.
The SOC of one type of energy storage battery pack is any higher-level controller of the energy storage battery pack, and is directly obtained from a corresponding group-level management unit in the battery system, and how the group-level management unit obtains the SOC of the one type of energy storage battery pack will be described in detail below, and will not be described herein again.
The above is only one embodiment of determining the operating state change of one type of energy storage battery pack when the operating state change is the SOC change, and in practical applications, including but not limited to this, this is not specifically limited herein, and it is considered that the present invention is within the protection scope of the present application.
And S120, determining the working state change of the second type of energy storage battery pack according to the determined working state change of the first type of energy storage battery pack based on the current of each path of energy storage battery pack.
When the operating state change is the SOC change, as shown in fig. 2, one example of determining the operating state change of the two types of energy storage battery packs is:
s210, determining the change of the residual capacity of the first type of energy storage battery pack according to the determined change of the SOC of the first type of energy storage battery pack.
Specifically, the remaining capacity change Δ C1= C1 × (SOC 12-SOC 11) for one type of energy storage battery pack, where C1 is the actual capacity of one type of energy storage battery pack.
S220, determining the residual capacity change of the second type of energy storage battery pack on the basis of the current of the second type of energy storage battery pack by utilizing the mapping relation between the current of the first type of energy storage battery pack and the residual capacity change of the first type of energy storage battery pack.
Specifically, the residual capacity change Δ C2= I2 × (Δ C1/I1) of the second type of energy storage battery pack, wherein I1 is the current of the first type of energy storage battery pack, I2 is the current of the second type of energy storage battery pack, and Δ C1/I1 represents the mapping relation between the current of the first type of energy storage battery pack and the residual capacity change of the battery pack.
And S230, determining the SOC change of the secondary energy storage battery pack according to the residual capacity change of the secondary energy storage battery pack.
Specifically, the SOC change of the class ii energy storage battery pack is Δ SOC2= Δ C2/C2, where C2 is the actual capacity of the class ii energy storage battery pack.
In practical applications, the actual capacity of each energy storage battery pack (for example, one-way first-class energy storage battery pack and multiple-way second-class energy storage battery packs) may be any one of the following situations:
(1) as shown in fig. 10a, the actual capacity of each of the two types of energy storage battery packs is aligned and equal to the actual capacity of one type of energy storage battery pack.
(2) As shown in fig. 10b, the actual capacity of each of the two types of energy storage battery packs is not aligned and is smaller than that of the one type of energy storage battery pack.
(3) As shown in fig. 10c, the actual capacity of each of the two types of energy storage battery packs is not aligned and is larger than that of the one type of energy storage battery pack.
As can be seen from steps S210 to S230, the above-described embodiment of step S120 can be applied to any of the cases shown in fig. 10a to 10 c.
The above is only one embodiment of determining the operating state change of the two types of energy storage battery packs when the operating state change is the SOC change, and in practical applications, including but not limited to this, this is not specifically limited herein, and it is considered that the present invention is within the protection scope of the present application.
And S130, determining the current SOC of the corresponding secondary energy storage battery pack according to the determined working state change of the secondary energy storage battery pack.
When the operating state changes to SOC changes, one example of determining the current SOC of the corresponding two types of energy storage battery packs is:
and determining the current SOC of the secondary energy storage battery pack according to the SOC change of the secondary energy storage battery pack and the last SOC.
Specifically, if the current SOC of the two types of energy storage battery packs is SOC22, SOC22= Δ SOC2+ SOC21, where SOC21 is the last SOC of the two types of energy storage battery packs.
The above is only one embodiment of determining the current SOC of the corresponding two types of energy storage battery packs when the operating state change is the SOC change, and in practical applications, including but not limited to this, this is not specifically limited herein, and it is considered that the present invention is within the protection scope of the present application.
Because the open-circuit voltage of the first type of energy storage battery pack and the SOC are in a linear relation, the change of the working state of the first type of energy storage battery pack is determined by utilizing the SOC of the first type of energy storage battery pack, so that the change of the working state of the first type of energy storage battery pack is closer to the actual change, the change of the working state of the second type of energy storage battery pack determined according to the change of the working state of the second type of energy storage battery pack and the current SOC of the second type of energy storage battery pack estimated according to the change of the working state of the second type of energy storage battery pack is also closer to the actual value, and therefore, the estimation method can improve the estimation accuracy of the SOC of the second type of energy storage battery pack; because the lithium iron phosphate battery is contained in the second type of energy storage battery pack, the SOC estimation method of the energy storage system can improve the SOC estimation precision of the lithium iron phosphate battery.
Another embodiment of the present application provides a specific implementation manner of step S120, which is applicable to the following cases: in step S110, the working state change of only one path of the first-class energy storage battery pack is determined, and in step S120, the working state change of at least two paths of the second-class energy storage battery packs is determined; the specific flow of this embodiment of step S120 is shown in fig. 3, and specifically includes the following steps:
and S310, respectively determining the working state changes of the two types of energy storage battery packs of different paths according to the working state changes of the one type of energy storage battery pack of one path determined based on the current of each path of energy storage battery pack.
For example, if the working state change of the first path of first-class energy storage battery pack is determined in step S110, and the working state change of the first path of second-class energy storage battery pack and the working state change of the second path of second-class energy storage battery pack are respectively determined in step S120, the working state changes of the first path of first-class energy storage battery pack and the second path of second-class energy storage battery pack may both be determined according to the working state change of the first path of first-class energy storage battery pack.
The determination process of the working state change of each path of the two types of energy storage battery packs is the same as the above process, and is not described herein again.
The present embodiment further provides a specific implementation manner of step S120, and this implementation manner is applicable to the following cases: in step S110, determining the working state change of at least two first-type energy storage battery packs, and in step S120, determining the working state change of at least two second-type energy storage battery packs; the specific flow of this embodiment of step S120 is shown in fig. 4, and specifically includes the following steps:
and S410, respectively determining the working state change of the corresponding second-class energy storage battery pack according to the determined working state change of the first-class energy storage battery pack of each path based on the current of each path of energy storage battery pack.
For example, if the working state change of the first-path first-type energy storage battery pack and the working state change of the second-path first-type energy storage battery pack are respectively determined in step S110, and the working state change of the first-path second-type energy storage battery pack and the working state change of the second-path second-type energy storage battery pack are respectively determined in step S120, the working state change of the first-path second-type energy storage battery pack may be determined according to the working state change of the first-path first-type energy storage battery pack, and the working state change of the second-path second-type energy storage battery pack may be determined according to the working state change of the second-path first-type energy storage battery pack.
The determination process of the working state change of each path of the two types of energy storage battery packs is the same as the above process, and is not described herein again.
Another embodiment of the present application provides an energy storage system, which has a specific structure as shown in fig. 5, and specifically includes: a power conversion unit 100, an LC 200 (Local controller), a battery System 300, and an EMS 500 (Energy Management System); the specific connection relationship is as follows:
the battery system 300 is connected to a first side of the power conversion unit 100, and a second side of the power conversion unit 100 is connected to the grid 400; LC 200 is connected to battery system 300, and LC 200 is connected (as shown in fig. 5) or disconnected to power conversion unit 100; the EMS 500 is connected to the LC 200, the power conversion unit 100, the grid dispatching center 700, and the BDC 600 (Cell Data center), respectively.
In this embodiment, the operating principle of the energy storage system is different from that of the energy storage system in the prior art in that: in this embodiment, any upper controller of the energy storage battery packs may execute the SOC estimation method of the energy storage system provided in the above embodiment, that is, the SOC of the two types of energy storage battery packs in the battery system 300 may be calibrated, so that the SOC estimation accuracy of the two types of energy storage battery packs may be improved, and the operating state of the battery system 300 may be adjusted more accurately.
It should be noted that other working principles of the energy storage system provided in this embodiment are the same as those in the prior art, and are not described herein again.
In this embodiment, when two types of energy storage battery packs simultaneously operate, any higher controller of the energy storage battery packs performs capacity calibration and health recognition on the two types of energy storage battery packs by using the first type of energy storage battery pack.
The actual capacity of the second-class energy storage battery pack is calibrated, so that the accumulated error can be eliminated; and the health state of each two types of energy storage battery packs can be mastered in time through the identification of the health degree.
In this embodiment, any upper controller of the energy storage battery pack further controls the second type of energy storage battery pack to start to operate after the first type of energy storage battery pack operates for a preset time.
In practical application, before the second-class energy storage battery pack works, the corresponding first-class energy storage battery pack can be controlled to work by one-way first-class energy storage battery pack, and can also be controlled by all the first-class energy storage battery packs to work.
The preset time is set according to the actual situation, and is not specifically limited herein; generally, after the corresponding type of energy storage battery pack works for a preset time, the cooling liquid of the battery system 300 is heated to a certain temperature, and lithium precipitation is not easy to occur in the type two energy storage battery pack 332 at the certain temperature.
In this embodiment, the embodiment of the battery system 300 can avoid safety accidents, so as to improve safety of the battery system and reduce the life cycle cost of the battery system.
Another embodiment of the present application further provides a specific implementation of the battery system 300, which is specifically configured as shown in fig. 6, and includes: BSC 310 (Battery system controller), at least one first-type energy storage Battery pack 331, at least one second-type energy storage Battery pack 332, and at least one pack-level management unit 320; the specific connection relationship is as follows:
a first side of the group level management unit 320 is connected to the energy storage battery packs corresponding to one another, and a second side of the group level management unit 320 is used as a corresponding power connection end of the battery system 300; BSC 310 is connected to each group level management unit 320, and BSC 310 is connected to LC 200 (not shown in fig. 6).
It should be noted that, in general, as shown in fig. 6, a switch is provided between the energy storage battery pack and the corresponding group level management unit 320, and a switch is also provided between the group level management unit 320 and the corresponding power connection end of the battery system 300; the above two points are already common means in the prior art, and therefore are not described in detail here.
Optionally, the group level management unit 320 may be a DCAC converter 322 (as shown in fig. 9) or a DCDC converter 321 (as shown in fig. 8), which is not specifically limited herein as the case may be, and is within the protection scope of the present application.
It should be noted that, when the group level management unit 320 is the DCAC converter 322, the number of the battery cells included in each energy storage battery group is determined by the dc voltage range of the DCAC converter 322; when the group level management unit 320 is the DCDC converter 321, the number of the battery units included in each energy storage battery group is determined by the mapping relationship between the direct-current voltage range of the DCDC converter 321 and the SOC of each energy storage battery group.
The number of the energy storage battery packs and the number of the pack level management units 320 may be determined according to specific situations, and are not specifically limited herein, and are within the protection scope of the present application.
During operation, each energy storage battery pack may exchange electric energy with the power grid 400, or each energy storage battery pack may exchange electric energy, and a specific control process is the same as that in the prior art, and is not described herein again.
In the working process of each energy storage battery pack, the pack-level management unit 320 measures and calculates the SOC of the corresponding energy storage battery pack in real time and uploads the SOC to the BSC 310.
Specifically, since the OCV and the SOC of the first-class energy storage battery pack 331 are in a linear relationship, the SOC of the first-class energy storage battery pack 331 can be measured and calculated by an open-circuit voltage method or an ampere-hour integration method within the full-capacity range of the first-class energy storage battery pack 331; in addition, since the OCV and the SOC of the class ii energy storage battery pack 332 are in a nonlinear relationship, specifically, when the SOC of the class ii energy storage battery pack 332 is between 10% and 90%, the OCV and the SOC are in a nonlinear relationship, the SOC can be measured and calculated by an open-circuit voltage ampere-hour integration method within a specific range of the class ii energy storage battery pack 332.
It should be noted that both the open circuit voltage method and the ampere-hour integration method are well established techniques in the prior art, and are not described in detail here.
In another embodiment of the present application, all the energy storage battery packs may be installed in the same independent chamber; or the first-type energy storage battery pack 331 and the second-type energy storage battery pack 332 are respectively arranged in different independent chambers; in practical applications, including but not limited to, this, can be determined according to specific situations and is within the protection scope of the present application.
It should be noted that, the second embodiment can ensure that thermal accidents of each energy storage battery pack do not mutually affect, thereby reducing the influence caused by the thermal accidents and improving the safety of the battery system 300.
In another embodiment of the present application, the energy storage battery pack and the pack-level management unit 320 are each installed in different independent chambers; therefore, the insecurity of the battery system 300 can be reduced, and the influence of the thermal accident of the group level management unit 320 on the energy storage battery pack can be avoided.
In another embodiment of the present application, as shown in fig. 7, the battery system 300 further includes: battery fire management unit 340 and battery thermal management unit 350; wherein, the battery fire management unit 340 and the battery thermal management unit 350 are both connected with the BSC 310; all energy storage battery packs share a battery fire management unit 340 and a battery thermal management unit 350.
It should be noted that the functions of the battery fire management unit 340 and the battery thermal management unit 350 are the same as those of the prior art, and are not described herein again.
Another embodiment of the present application provides a specific implementation manner of the power conversion unit 100, which is applicable to a case where the group level management unit 320 in the battery system 300 is a DCDC converter 321, and the specific structure thereof is shown in fig. 8 (not shown in the figures, the EMS 500, the BDC 600, and the grid dispatching center 700), including: PCS 110 (Power Conversion System, energy storage converter) and transformer 120; the specific connection relationship is as follows:
the dc side of the PCS 110 is connected to the corresponding power connection terminal of the battery system 300, the ac side of the PCS 110 is connected to the primary side of the transformer 120, the secondary side of the transformer 120 is connected to the grid 400, and the PCS 110 is connected to the LC 200.
It should be noted that, in general, as shown in fig. 8, the corresponding power connection terminals of the battery system 300 are connected to the dc side of the PCS 110 through switches, and this is a common means in the prior art, and therefore, it is not described here.
The present embodiment further provides another specific implementation of the power conversion unit 100, which is suitable for a case where the group level management unit 320 in the battery system 300 is a DCAC converter 322, and the specific structure thereof is shown in fig. 9 (the EMS 500, the BDC 600, and the grid dispatching center 700 are not shown in the figure), including: a transformer 120 and a low voltage combiner cabinet 130; the specific connection relationship is as follows:
the first side of the low voltage combiner cabinet 130 is connected to the corresponding power connection terminal of the battery system 300, the second side of the low voltage combiner cabinet 130 is connected to the primary side of the transformer 120, and the secondary side of the transformer 120 is connected to the grid 400; each DCAC inverter 322 in the battery system 300 is connected to the LC 200 (only the LC 200 and one DCAC inverter 322 are shown in fig. 9 as an example).
The above two embodiments of the power conversion unit 100 in the two embodiments of the battery system 300 are only two embodiments, and in practical applications, including but not limited to this, the embodiments are not limited to this, and the invention is within the protection scope of the present application.
In the above embodiment, only when two types of energy storage battery packs simultaneously operate, the SOC of the two types of energy storage battery packs 332 can be calibrated, and in order to calibrate the SOC of the two types of energy storage battery packs 332 in the operating process, another embodiment of the present application provides another three embodiments of the energy storage system.
The first embodiment is applicable to both the case where the group level management unit 320 is the DCDC converter 321 and the case where the group level management unit 320 is the DCAC converter 322, and the embodiment is different from the embodiment provided in the above embodiment in that: in this embodiment, the LC 200 distributes the current of each energy storage battery pack through the BSC 310, so that the first type energy storage battery pack 331 is always in an operating state during the operation of the second type energy storage battery pack 332.
The second embodiment is applicable to the case where the group level management unit 320 is a DCDC converter 321, and the embodiment is different from the embodiments provided in the above embodiments in that: in this embodiment, the LC 200 distributes the current to each energy storage battery pack through the PCS, so that the first type energy storage battery pack 331 is always in the working state during the working process of the second type energy storage battery pack 332.
The third embodiment is applicable to the case where the group level management unit 320 is a DCAC converter 322, and the embodiment is different from the embodiment provided in the above embodiment in that: in this embodiment, LC 200 distributes the current to each energy storage battery pack via each DCAC inverter 322.
Optionally, in the working process of the second-type energy storage battery pack 332, a certain path of the first-type energy storage battery pack 331 may be kept in a working state all the time, or may be divided into different stages, and different types of energy storage battery packs 331 are kept in a working state in each stage, or both of the above two cases may exist, which are not specifically limited herein, and are within the protection scope of the present application, and may be determined according to specific situations.
Since the first-type energy storage battery pack 331 is always in the working state in the working process of the second-type energy storage battery pack 332 through current distribution, in this embodiment, the SOC of the second-type energy storage battery pack 332 can be calibrated in the working process of the second-type energy storage battery pack 332.
When the second-type energy storage battery pack 332 is in a working state within the full-capacity range of the second-type energy storage battery pack 332, the SOC of the second-type energy storage battery pack 332 can be calibrated within the full-capacity range of the second-type energy storage battery pack 332 by the three implementation modes in the embodiment, so that the SOC estimation accuracy of the second-type energy storage battery pack 332 can be improved within the full-capacity range of the second-type energy storage battery pack 332.
In the above description of the disclosed embodiments, features described in various embodiments in this specification can be substituted for or combined with each other to enable those skilled in the art to make or use the present application. The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.

Claims (16)

1. A method for estimating SOC of an energy storage system, wherein a battery system in the energy storage system includes: the system comprises a first-class energy storage battery pack with an open-circuit voltage and SOC in a linear relation and a second-class energy storage battery pack with an open-circuit voltage and SOC in a nonlinear relation; the SOC estimation method is applied to any upper-level controller of the energy storage battery pack; the SOC estimation method comprises the following steps:
when two types of energy storage battery packs work simultaneously, determining the change of the working state of one type of energy storage battery pack by using the SOC of the one type of energy storage battery pack;
determining the working state change of the second type of energy storage battery pack according to the determined working state change of the first type of energy storage battery pack based on the current of each path of energy storage battery pack;
and determining the current SOC of the corresponding secondary energy storage battery pack according to the determined working state change of the secondary energy storage battery pack.
2. The SOC estimation method of the energy storage system according to claim 1, wherein the operating state change includes: any one of SOC variation, remaining capacity variation, and discharge amount variation.
3. The SOC estimation method of the energy storage system according to claim 2, wherein when the operating state change is an SOC change, the process of determining the operating state change of the two types of energy storage battery packs specifically includes:
determining the change of the residual capacity of the first type of energy storage battery pack according to the determined change of the SOC of the first type of energy storage battery pack;
determining the residual capacity change of the second type of energy storage battery pack according to the current of the second type of energy storage battery pack based on the mapping relation between the current of the first type of energy storage battery pack and the residual capacity change of the second type of energy storage battery pack;
and determining the SOC change of the second type of energy storage battery pack according to the residual capacity change of the second type of energy storage battery pack.
4. The method for estimating SOC of an energy storage system according to any one of claims 1 to 3, wherein if the number of the first type of energy storage battery pack determined to undergo a change in operating state is 1 and the number of the second type of energy storage battery pack determined to undergo a change in operating state is greater than 1, determining a change in operating state of the second type of energy storage battery pack according to the determined change in operating state of the first type of energy storage battery pack, includes:
and respectively determining the working state changes of the two types of energy storage battery packs of different paths according to the determined working state change of the one type of energy storage battery pack.
5. The method for estimating SOC of an energy storage system according to any one of claims 1 to 3, wherein if the number of the first type of energy storage battery pack determined to undergo a change in operating state is greater than 1 and the number of the second type of energy storage battery pack determined to undergo a change in operating state is greater than 1, determining a change in operating state of the second type of energy storage battery pack according to the determined change in operating state of the first type of energy storage battery pack, includes:
and respectively determining the working state change of the corresponding second type of energy storage battery pack according to the determined working state change of the first type of energy storage battery pack of each path.
6. An energy storage system, comprising: a battery system, a power conversion unit, a local controller, and an energy management system; wherein:
the battery system is connected to the first side of the power conversion unit, and the second side of the power conversion unit is connected with a power grid;
the local controller is connected with the battery system, and the local controller is connected with or disconnected from the power conversion unit;
the energy management system is respectively connected with the local controller, the power conversion unit, the power grid dispatching center and the battery cell data center;
the battery system comprises an energy storage battery pack, and any superior controller of the energy storage battery pack is used for executing the SOC estimation method of the energy storage system according to any one of claims 1-5.
7. The energy storage system of claim 6, wherein the battery system comprises: the system comprises a battery system controller BSC, at least one path of first-class energy storage battery pack, at least one path of second-class energy storage battery pack and at least one pack level management unit; wherein:
the first sides of the group level management units are connected with the energy storage battery packs in one-to-one correspondence, and the second sides of the group level management units are used as corresponding electric power connecting ends of the battery system;
and the battery system controller is respectively connected with each group level management unit and the local controller.
8. The energy storage system of claim 7, wherein the local controller is configured to distribute current to each energy storage battery pack through the battery system controller; the current distribution aims to ensure that the first-class energy storage battery pack is in a working state all the time in the working process of the second-class energy storage battery pack.
9. The energy storage system of claim 7, wherein the group level management unit is a DCDC converter, and the power conversion unit comprises: an energy storage converter and a transformer; wherein:
the direct current side of the energy storage converter is connected with the corresponding power connection end of the battery system, the alternating current side of the energy storage converter is connected with the primary side of the transformer, and the secondary side of the transformer is connected with the power grid.
10. The energy storage system of claim 9, wherein the local controller is further connected to the energy storage converter, and the local controller is configured to distribute current to each energy storage battery pack through the energy storage converter; the current distribution aims to ensure that the first-class energy storage battery pack is in a working state all the time in the working process of the second-class energy storage battery pack.
11. The energy storage system of claim 7, wherein the group level management unit is a DCAC converter, and the power conversion unit comprises: a low voltage combiner and transformer; wherein:
the first side of the low-voltage confluence cabinet is respectively connected with the corresponding power connecting end of the battery system, the second side of the low-voltage confluence cabinet is connected with the primary side of the transformer, and the secondary side of the transformer is connected with the power grid;
each DCAC converter is connected with the local controller.
12. The energy storage system of claim 11, wherein the local controller is configured to distribute current to each energy storage battery pack via each DCAC converter; the current distribution aims to ensure that the first-class energy storage battery pack is in a working state all the time in the working process of the second-class energy storage battery pack.
13. The energy storage system of claim 7, wherein the energy storage battery pack and the pack-level management unit are each mounted in different independent chambers;
all the energy storage battery packs are arranged in the same independent cavity, or the first type of energy storage battery pack and the second type of energy storage battery pack are respectively arranged in different independent cavities.
14. The energy storage system of claim 7, wherein the battery system further comprises: the battery fire control management unit and the battery thermal management unit; wherein:
all the battery fire-fighting management units and all the battery thermal management units are connected with the battery system controller;
all the energy storage battery packs share the battery fire protection management unit and the battery thermal management unit.
15. The energy storage system according to any one of claims 6 to 14, wherein any upper controller of the energy storage battery pack is further configured to:
when the two types of energy storage battery packs work simultaneously, the first type of energy storage battery pack is used for carrying out capacity calibration and health degree identification on the second type of energy storage battery pack.
16. The energy storage system according to any one of claims 6 to 14, wherein any upper controller of the energy storage battery pack is further configured to:
and controlling the second-class energy storage battery pack to start to work after the first-class energy storage battery pack works for a preset time.
CN202210308600.9A 2022-03-28 2022-03-28 Energy storage system and SOC estimation method thereof Active CN114415055B (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29521212U1 (en) * 1995-05-22 1996-10-17 Mentzer Electronic GmbH, 61200 Wölfersheim Device for measuring partial voltages
CN104965179A (en) * 2015-07-06 2015-10-07 首都师范大学 Lithium ion storage battery temperature combinational circuit model and parameter identification method thereof
US20160084913A1 (en) * 2013-05-29 2016-03-24 Freescale Semiconductor, Inc. Cell monitoring apparatus, battery monitoring apparatus, integrated circuit and method of monitoring a rechargeable cell
CN109669134A (en) * 2019-02-27 2019-04-23 浙江科技学院 A kind of evaluation method of the SOC based on Kalman filtering method
CN110133505A (en) * 2018-02-05 2019-08-16 南京湛研能源科技有限公司 A kind of power battery charging and discharging state observation method based on variable parameter model
US20200124675A1 (en) * 2018-10-23 2020-04-23 Samsung Electronics Co., Ltd. Method and system for direct estimation of exact power in real-time

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29521212U1 (en) * 1995-05-22 1996-10-17 Mentzer Electronic GmbH, 61200 Wölfersheim Device for measuring partial voltages
US20160084913A1 (en) * 2013-05-29 2016-03-24 Freescale Semiconductor, Inc. Cell monitoring apparatus, battery monitoring apparatus, integrated circuit and method of monitoring a rechargeable cell
CN104965179A (en) * 2015-07-06 2015-10-07 首都师范大学 Lithium ion storage battery temperature combinational circuit model and parameter identification method thereof
CN110133505A (en) * 2018-02-05 2019-08-16 南京湛研能源科技有限公司 A kind of power battery charging and discharging state observation method based on variable parameter model
US20200124675A1 (en) * 2018-10-23 2020-04-23 Samsung Electronics Co., Ltd. Method and system for direct estimation of exact power in real-time
CN109669134A (en) * 2019-02-27 2019-04-23 浙江科技学院 A kind of evaluation method of the SOC based on Kalman filtering method

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