Method, system and device for improving reconfigurable battery network and medium

Abstract

The invention provides a method, a system, equipment and a medium for improving a reconfigurable battery network, and the method comprises the steps: determining the number of series and parallel battery units in the reconfigurable battery network according to a load demand, and building a reconfigurable battery network model by taking an output voltage during given operation and the output power of the system as constraint conditions; based on the basic information of the battery units in the reconfigurable battery network model, the equalization requirements of the battery units are evaluated, an equalization strategy of each battery unit is established, and the equalization strategy comprises an equalization mode of each battery unit and the priority of the equalization mode; giving a corresponding switch driving signal to the reconfigurable battery network model, and reconfiguring the connection between the battery units based on an equalization strategy; monitoring the voltage, the state of charge (SOC) and the temperature of the battery unit, and evaluating and adjusting the current equalization strategy according to the real-time data; and if the equalization strategy reaches the constraint condition, equalization monitoring is stopped, and the optimized reconfigurable battery network model is obtained.

Description

Technical Field

[0001] The present invention belongs to the field of energy storage technology, and in particular relates to a method and device for improving the topology and mode control of a reconfigurable battery. Background Art

[0002] In the era of energy internet, battery energy storage systems are widely used in various industrial, commercial and residential scenarios as key technologies. Therefore, the main performance indicators of battery energy storage systems, such as efficiency, reliability and safety, are crucial to the successful commercial deployment of energy storage systems. These indicators not only affect the direct application effect of the system, but also are related to the global optimization of energy management and the popularization and promotion of renewable energy.

[0003] Due to differences in manufacturing processes and usage environments, traditional battery energy storage systems have inconsistencies in parameters such as capacity and internal resistance of each single cell in the battery pack, resulting in mutual constraints between cells during use. This will not only reduce the available capacity of the battery and shorten the cycle life, but also greatly limit the energy utilization efficiency of the battery pack. In order to address the problem that the fixed topology of traditional batteries causes poor consistency in battery packs, active balancing and passive balancing are currently the most commonly used. However, passive balancing is to dissipate high-energy batteries through resistive discharge, which will cause energy loss in the energy storage system and put higher requirements on the thermal management of the system. Although active balancing can improve battery consistency and improve battery pack efficiency, its balancing system is highly complex and expensive.

[0004] Reconfigurable battery networks provide a new approach to solving the above problems. This network introduces power electronic switching devices based on traditional battery topology, and optimizes energy utilization and performance by dynamically adjusting the battery configuration and connection method within the battery pack. This structure can change the series or parallel connection mode of battery modules according to specific application scenarios and actual needs, thereby achieving higher efficiency, flexibility and reliability. Although the introduction of power electronic switches can improve the consistency of battery energy storage systems, frequent state switching also poses a hidden danger to the safety of the system. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method, system, device and medium for improving a reconfigurable battery network, so as to solve the technical problem of potential safety hazards caused by frequent switching of switches in a reconfigurable battery network in the prior related technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for improving a reconfigurable battery network, comprising: According to the load demand, determine the number of series-parallel battery cells in the reconfigurable battery network, take the output voltage and system output power at a given runtime as constraints, and build a reconfigurable battery network model; Based on the basic information of the battery cells in the reconfigurable battery network model, the balancing demand of each battery cell is evaluated to obtain an evaluation result; according to the evaluation result, different balancing strategies are established by using balancing indicators, that is, by using the values ​​of the SOC standard deviation and the range of the battery; the balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode; the balancing modes include two balancing modes: single cell balancing and battery pack balancing; Giving corresponding switch drive signals to the reconfigurable battery network model, and reconfiguring the connections between the battery cells based on a balancing strategy; The voltage, state of charge (SOC) and temperature of the battery cells are monitored, and the current balancing strategy is evaluated and adjusted according to the real-time data; if the balancing strategy reaches the constraint conditions, the balancing monitoring is stopped to obtain an optimized reconfigurable battery network model.

[0007] Preferably, based on the basic information of the battery cells in the reconfigurable battery network model, the process of evaluating the balancing requirement of each battery cell is as follows: Testing the open circuit voltage and state of charge SOC reference relationship of the battery unit to obtain the open circuit voltage and state of charge SOC reference relationship curve; Based on the open circuit voltage and state of charge SOC reference relationship curve, the initial voltage and state of charge SOC of all batteries are obtained to obtain the sample standard deviation and range of the state of charge SOC of the battery cells; Compare the sample standard deviation and range of the state of charge (SOC) of the battery cell with a preset threshold value to evaluate the balancing requirement of each battery cell; The reconfigurable battery network adopts a cross-type configuration. The reconfigurable battery network includes a plurality of battery cells arranged in an array. Each of the battery cells is connected in parallel with a bypass switch. A series switch is connected in series between adjacent battery cells in the lateral direction, and a parallel switch is also connected in parallel between adjacent battery cells; Parallel switches are connected in parallel between the adjacent battery cells in the longitudinal direction.

[0008] Furthermore, the sample standard deviation and range of the state of charge SOC of the battery cell are compared with a preset threshold value, and the process of evaluating the balancing requirement of each battery cell is as follows:

[0009] In the formula, , is the set standard deviation threshold, , is the set extreme value threshold, is the sample standard deviation, The sample is extremely poor; It is a balancing mode when the battery consistency is good. This is a balancing mode when battery consistency is poor.

[0010] Preferably, the balancing mode includes a multi-battery series-first-parallel-later balancing mode and a single-battery balancing mode; The multi-battery series-first-parallel-later balancing mode is to perform a balancing operation in a series-first-parallel-later manner when the battery consistency is good. The balancing operation is energy transfer between battery groups. The single cell balancing mode is that when the battery consistency is poor, each battery cell performs a balancing operation individually, and a switch device is used to switch between the battery cells multiple times to achieve energy transfer. At this time, the series connection first and then parallel connection changes to parallel connection first and then series connection; The priorities of the balancing modes are: The priority of the balancing mode is selected according to the state of charge of the battery cells. When charging, the battery cells with low power are selected to be charged first, and when discharging, the battery cells with high power are selected to be discharged first; The battery cells are disconnected one by one when they are fully charged or discharged.

[0011] Preferably, according to the load demand, the process of determining the number of battery cells connected in series and parallel in the reconfigurable battery network is as follows: Calculate the number of series:

[0012] Calculate the number of parallel connections:

[0013] In the formula, is the load voltage, is the load current is the voltage of each battery cell, is the current of each battery cell, is the number of batteries connected in series, is the number of batteries connected in parallel.

[0014] Preferably, the total output voltage and current of the reconfigurable battery network model and the load required voltage and current satisfy:

[0015] In the formula, , To select the total output voltage and current on the path, , For the load voltage and current that need to be met, the values ​​of v and i are usually very small; The output power constraint of the system is: the output power of the reconfigurable battery network under the selected path must meet the normal operating power of the load:

[0016] In the formula, is the total power output by the battery topology, Pmin is the minimum power required by the system load, and Pmax is the maximum power that the battery topology can output.

[0017] Preferably, if the balancing strategy reaches the constraint condition, each battery unit of the reconfigurable battery network model is cut off when it is charged to the state of charge SOC=1; When each battery cell of the reconfigurable battery network model is discharged to a state of charge SOC=0, the battery cell is cut off; When all battery cells are charged or discharged, the normal battery pack connection state is restored.

[0018] In a second aspect, the present invention further provides a system for improving a reconfigurable battery network, based on the above-mentioned method for improving a reconfigurable battery network, comprising: Initialization unit, configured as: It is used to determine the number of series-parallel battery cells in the reconfigurable battery network according to the load demand, and to build a reconfigurable battery network model by taking the output voltage and the output power of the system as constraints when given operation; The balancing unit is configured as: Used to evaluate the balancing demand of each battery cell based on the basic information of the battery cell in the reconfigurable battery network model to obtain an evaluation result; according to the evaluation result, using the balancing index, that is, through the SOC standard deviation and range value of the battery, establish different balancing strategies; the balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode; the balancing mode includes two balancing modes: single cell balancing and battery pack balancing; The optimization unit is configured as: Used to give a corresponding switch drive signal to the reconfigurable battery network model, and reconfigure the connection between the battery cells based on the balancing strategy; Output unit, configured as: It is used to monitor the voltage, state of charge (SOC) and temperature of the battery cells, and evaluate and adjust the current balancing strategy according to the real-time data; if the balancing strategy reaches the constraint conditions, the balancing monitoring is stopped to obtain an optimized reconfigurable battery network model.

[0019] In a third aspect, the present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for improving a reconfigurable battery network as described above when executing the computer program.

[0020] In a fourth aspect, the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for improving a reconfigurable battery network as described above are implemented.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a method, system, device and medium for improving a reconfigurable battery network. The network topology is designed to have high flexibility and can be connected in series, in parallel, in series first and then in parallel, and in parallel first and then in series. According to load demand, the number of battery cells connected in series and in parallel in the reconfigurable battery network is determined, and a reconfigurable battery network model is constructed by taking the output voltage and the output power of the system at a given operation as constraints. Based on the basic information of the battery cells in the reconfigurable battery network model, the balancing demand of each battery cell is evaluated, and a balancing strategy for each battery cell is established, wherein the balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode. A corresponding switch driving signal is given to the reconfigurable battery network model, and the battery is reconfigured based on the balancing strategy. The present invention relates to a battery network comprising a plurality of battery cells, a plurality of battery cells, and a plurality of battery cells. The plurality of battery cells are connected to each other; the voltage, state of charge (SOC) and temperature of the battery cells are monitored, and the current balancing strategy is evaluated and adjusted according to the real-time data; if the balancing strategy reaches the constraint condition, the balancing monitoring is stopped to obtain an optimized reconfigurable battery network model; the present application takes advantage of the reconfigurable battery network, fully considers the impact of the frequent switching of the switching devices on the safety of the energy storage system, and proposes a sub-mode balancing strategy, which can improve the battery balancing consistency while improving the safety. Specifically, the present application calculates the SOC standard deviation and the range of the battery at a certain moment, sets the balancing mode priority, and uses the selection of the balancing mode to effectively improve the inconsistency of the battery pack. At the same time, the number of switch switching times can be reduced during the charging and discharging process, thereby improving the system safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of a method for improving a reconfigurable battery network according to an embodiment of the present disclosure is shown; Figure 2 A reference SOC-OCV curve at room temperature 25° C. of an embodiment of the present disclosure is shown; Figure 3 A reconfigurable battery network topology diagram according to an embodiment of the present disclosure is shown; Figure 4A schematic diagram of switching of a reconfigurable battery network mode according to an embodiment of the present disclosure is shown; Figure 5 The figure shows the discharge SOC result of the traditional battery network in the prior art; Figure 6 The diagram shows the discharge SOC result when the SOC consistency of the reconfigurable battery network in the embodiment of the present disclosure is very good, with different modes of balancing; Figure 7 The diagram shows the discharge SOC result when the reconfigurable battery network is balanced in different modes and the SOC consistency is good according to the embodiment of the present disclosure; Figure 8 The diagram shows the discharge SOC result when the SOC consistency is poor for the reconstructed battery network mode balancing according to the embodiment of the present disclosure; Fig. 9 A comparison chart of the number of switching actions at different frequencies before and after the split mode of an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0023] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0027] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0028] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0029] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0030] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] Figure 3 A reconfigurable battery network topology diagram according to an embodiment of the present disclosure is shown. Figure 3 As shown, The reconfigurable battery network adopts a cross-type configuration. The reconfigurable battery network includes a plurality of battery cells arranged in an array. Each of the battery cells is connected in parallel with a bypass switch. A series switch is connected in series between adjacent battery cells in the lateral direction, and a parallel switch is also connected in parallel between adjacent battery cells; A parallel switch is connected in parallel between the adjacent battery cells in the longitudinal direction; specifically, Figure 2 As shown: S ip is the bypass switch, S iq , S ir , S is All switches are connected in series, S i,j It is a parallel switch (i=1, 2, 3…n, j=1, 2, 3…n).

[0032] If the series switch S iq Closed, and the parallel switch S i,j Disconnect, then battery unit B 11 , B 12 , B 13 , B 14 , B 15 Series connection; If the series switch S 1q , S 1r , S 1s , and the parallel switch S 1,2 and S 1,3 Closed, the battery cell B 11 , B 21 , B 31 in parallel; If the series switch S 1q , S 2q , S 1r , S 2r Close, parallel switch S 1,2 Disconnect, then battery unit B 11 , B 12 Series connection, battery unit B 21 , B 22 In series, then in parallel; If the series switch S 1q , S 2q , S 1r , S 2r Closed, and the parallel switch S 1,2 Closed, the battery cell B 11 , B 21 Parallel connection, battery unit B 12 , B 22 Connect in parallel, then connect in series; If the series switch S 1p Closed, the battery cell B 11 , B 21 , B 31 Bypassed; This topology is highly flexible and can be connected in series, in parallel, in series first and then in parallel, or in parallel first and then in series. The number of batteries connected in series and in parallel is determined by the power requirements of the load.

[0033] Figure 1 A method for improving a reconfigurable battery network according to an embodiment of the present disclosure is shown. Figure 1 As shown, the following steps are included: Step S1: Determine the number of series-parallel battery cells in the reconfigurable battery network according to the load demand, take the output voltage and the output power of the system during the given operation as constraints, and build the reconfigurable battery network topology; Preferably, in the embodiment of the present disclosure, the process of evaluating the balancing requirement of each battery cell based on the basic information of the battery cells in the reconfigurable battery network topology is: Testing the open circuit voltage and state of charge SOC reference relationship of the battery unit to obtain the open circuit voltage and state of charge SOC reference relationship curve; Based on the open circuit voltage and state of charge SOC reference relationship curve, the initial voltage and state of charge SOC of all batteries are obtained to obtain the sample standard deviation and range of the state of charge SOC of the battery cells; The sample standard deviation and range of the state of charge (SOC) of the battery cell are compared with a preset threshold value to evaluate the balancing requirement of each battery cell.

[0034] Specifically, in the embodiment of the present disclosure, the process of testing the reference relationship between the open circuit voltage and the state of charge SOC of the battery cell and obtaining the reference relationship curve between the open circuit voltage OCV and the state of charge SOC is as follows: The open circuit voltage and state of charge (SOC) benchmark relationship of the battery is tested on the experimental platform, the corresponding curve is obtained, and the state of charge (SOC) value is fitted with the open circuit voltage (OCV) value. The fitting formula used in the fitting is as follows:

[0035] In the formula, k 0 , k 1 , k 2 , k 3 , k 4 is the coefficient.

[0036] The process of obtaining the initial voltage and the state of charge SOC of all batteries based on the open circuit voltage and the state of charge SOC reference relationship curve, and obtaining the sample standard deviation and range of the state of charge SOC of the battery cells is as follows: Build a reconfigurable battery network model, obtain the initial voltage, temperature, and state of charge (SOC) of all battery cells, and calculate the sample standard deviation εsoc and range εp of the battery state of charge (SOC) at that moment; The calculation formulas for sample standard deviation εsoc and range εp are:

[0037] Where n is the total number of battery cells, It represents the state of charge SOC of the ith battery cell at the end of discharge, It represents the average value of the state of charge (SOC) of all batteries at the end of discharge. , They respectively represent the maximum and minimum state of charge (SOC) of the single cell at the end of discharge.

[0038] Preferably, in the embodiment of the present disclosure, the sample standard deviation and range of the state of charge SOC of the battery cell are compared with a preset threshold value, and the process of evaluating the balancing requirement of each battery cell is as follows:

[0039] In the formula, , is the set standard deviation threshold, , is the set extreme value threshold, is the sample standard deviation, The sample is extremely poor; It is a balancing mode when the battery consistency is good. This is a balancing mode when battery consistency is poor.

[0040] Step S2: Based on the basic information of the battery cells in the reconfigurable battery network model, the balancing requirement of each battery cell is evaluated to obtain an evaluation result; according to the evaluation result, different balancing strategies are established by using balancing indicators, that is, by using the values ​​of the battery SOC standard deviation and range; the balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode; the balancing modes include two balancing modes: single cell balancing and battery pack balancing; Preferably, in the embodiment of the present disclosure, the balancing mode includes a multi-battery series-first and then parallel balancing mode and a single-battery balancing mode; The multi-battery series-first-parallel-later balancing mode is to perform a balancing operation in a series-first-parallel-later manner when the battery consistency is good. The balancing operation is energy transfer between battery groups. The single cell balancing mode is that when the battery consistency is poor, each battery cell performs a balancing operation individually, and a switch device is used to switch between the battery cells multiple times to achieve energy transfer. At this time, the series connection first and then parallel connection changes to parallel connection first and then series connection; The priorities of the balancing modes are: The priority of the balancing mode is selected according to the state of charge of the battery cells. When charging, the battery cells with low power are selected to be charged first, and when discharging, the battery cells with high power are selected to be discharged first; The battery cells are disconnected one by one when they are fully charged or discharged.

[0041] Preferably, in the embodiment of the present disclosure, the process of determining the number of series-parallel battery units in the reconfigurable battery network according to the load demand is: Calculate the number of series:

[0042] Calculate the number of parallel connections:

[0043] In the formula, is the load voltage, is the load current is the voltage of each battery cell, is the current of each battery cell, is the number of batteries connected in series, is the number of batteries connected in parallel.

[0044] Preferably, in the disclosed embodiment, the total output voltage and current of the reconfigurable battery network model satisfy the following relationship with the load demand voltage and current:

[0045] In the formula, , To select the total output voltage and current on the path, , For the load voltage and current that need to be met, the values ​​of v and i are usually very small; The output power constraint of the system is: the output power of the reconfigurable battery network under the selected path must meet the normal operating power of the load:

[0046] In the formula, is the total power output by the battery topology, Pmin is the minimum power required by the system load, and Pmax is the maximum power that the battery topology can output.

[0047] Step S3: giving a corresponding switch drive signal to the reconfigurable battery network topology, and reconfiguring the connection between the battery cells based on the balancing strategy; Step S4: monitor the voltage, state of charge SOC and temperature of the battery cells, and evaluate and adjust the current balancing strategy according to the real-time data; if the balancing strategy reaches the constraint condition, stop the balancing monitoring and obtain the optimized reconfigurable battery network topology.

[0048] Preferably, in the embodiment of the present disclosure, if the balancing strategy reaches the constraint condition, each battery unit of the reconfigurable battery network model is cut off when it is charged to the state of charge SOC=1; When each battery cell of the reconfigurable battery network model is discharged to a state of charge SOC=0, the battery cell is cut off; When all battery cells are charged or discharged, the normal battery pack connection state is restored.

[0049] Example This embodiment adopts Figure 3The vertical and horizontal reconfigurable battery network topology shown; The open circuit voltage and SOC benchmark data values ​​of the battery tested on the experimental platform are shown in Table 1, and the corresponding curves are obtained; Table 1 SOC 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 OCV 3.4666 3.5265 3.5683 3.6138 3.6695 3.7387 3.8230 3.9236 4.0418 The SOC value is fitted with the open circuit voltage OCV value to obtain the fitting curve as shown in Figure 1 As shown. The fitting formula is as follows:

[0050] The OCV-SOC relationship expression is as follows:

[0051] The comparison of mode balancing and switching times under different initial conditions of the overall SOC standard deviation and extreme difference of the energy storage system is mainly divided into three cases: very good consistency, good consistency and poor consistency. The initial SOC benchmark value data is shown in Table 2: Table 2

[0052] Obtain the initial voltage, temperature, and state of charge SOC of all batteries, and calculate the sample standard deviation εsoc and range εp of the battery SOC at that moment; the calculation formulas for the sample standard deviation εsoc and range εp are:

[0053] Case 1, the best consistency:

[0054] Case 2, poor consistency:

[0055] Case 3, poor consistency (i.e., when the barrel effect is severe):

[0056] After obtaining the values ​​of the sample standard deviation εsoc and the range εp, compare them with the set threshold to select the equalization mode:

[0057] Case 1: Since the battery consistency is very good, the entire balancing process uses mode 1 balancing; Case 2: Since the battery consistency is good, it will first enter Mode 1 balancing for a very short time, and then enter Mode 2 balancing; Case 3: Due to poor battery consistency, it will first enter Mode 1 balancing for a long time, and then enter Mode 2 balancing; Mode 1 refers to a multi-battery balancing mode where multiple batteries are connected in series first and then in parallel, and Mode 2 refers to a single-battery balancing mode; The specific process is as follows Figure 6 , Figure 7 and Figure 8 As shown, after the balancing mode is selected, the number of batteries in series and parallel is calculated according to the load demand. The capacity of the battery used in the present invention is 2500mAh, the nominal voltage is 3.6V, the battery pack output voltage range is set to [12V, 15V], the current output range is [3.5A, 5.5A], and the discharge rate is set to 1C.

[0058] Calculate the number of series: Minimum number of batteries in series:

[0059] To achieve the minimum output voltage of 12V, 3.33 batteries are required. Since the number of batteries must be an integer, at least 4 batteries are required to be connected in series to achieve the maximum voltage requirement of 12V.

[0060] Maximum number of batteries connected in series:

[0061] To achieve the maximum output voltage of 15V, 4.17 batteries are required to achieve the minimum output voltage of 15V. Similarly, the number of batteries must be an integer, and at least 5 batteries are required in series to achieve the minimum voltage requirement of 15V. Since the entire output voltage range needs to be covered, the number of battery strings should be between 4 and 5. With 5 batteries in series, the output voltage of the battery pack will be 5×3.6𝑉=18𝑉, which exceeds the maximum voltage requirement of 15V. Therefore, in order to meet the set battery pack output voltage range [12V, 15V], 4 batteries with a nominal voltage of 3.6V are required in series. In this way, the battery pack can provide the required minimum voltage without exceeding the maximum voltage limit.

[0062] Minimum number of batteries in parallel:

[0063] To achieve the minimum output current of 3.5A, 1.4 batteries are required because the discharge rate of a single battery is 2.5A. Since the number of batteries must be an integer, at least 2 batteries must be connected in parallel to achieve the minimum current requirement of 3.5A.

[0064] Maximum number of batteries in parallel:

[0065] To achieve the minimum output current of 5.5A, 2.2 batteries are required. Since the number of batteries must be an integer, at least 3 batteries are required in parallel to achieve the maximum current requirement of 5.5A. Since the entire output current range needs to be covered, the number of battery packs should be 2 or 3 in parallel. With 2 batteries in parallel, the output current of the battery pack can reach 2×2.5𝐴=5𝐴, which is within the range of 3.5A to 5.5A, but cannot meet the maximum requirement of 5.5A. With 3 batteries in parallel, the output current of the battery pack can reach 3×2.5𝐴=7.5𝐴, which exceeds the maximum current requirement of 5.5A. In order to meet the set battery pack output current range [3.5A, 5.5A], 2 batteries with a capacity of 2500mAh and a nominal voltage of 3.6V are required in parallel.

[0066] When meeting the requirements of each load, in order to reduce the circulating current and ensure the safety of the system, certain constraints need to be set. The total output voltage and current of the battery network should meet the requirements of the load voltage and current:

[0067]

[0068] System output power constraint: The output power of the reconfigurable battery network under the selected path must meet the normal operating power of the load. Therefore, it should meet:

[0069] After determining the load demand and selecting the mode, the battery priority is selected according to the battery SOC size. When charging, the battery with low power is selected first; when discharging, the battery with high power is selected first; the switch state is adjusted by selecting the battery, and the battery is disconnected in sequence when it is fully charged or discharged. According to the real-time status of the battery unit and system requirements, the series and parallel connection mode of the battery unit is dynamically adjusted to optimize the charging and discharging process, improve energy conversion efficiency and battery life.

[0070] Continuously monitor the voltage, SOC and temperature of the battery cells, adjust the current balancing strategy according to the real-time data, select the balancing mode, and ensure the balancing effect. When the battery SOC consistency changes with the charging and discharging process, the balancing mode will also switch. The mode switching process is as follows: Figure 4 .

[0071] Finally, it is determined whether the balancing operation has reached the preset target. When charging, SOC=1, the battery is removed; when discharging, SOC=0, the battery is removed; when all batteries are charged or discharged, the normal battery pack connection state is restored.

[0072] according to Figure 6 , Figure 7 and Figure 8It can be seen that the battery SOC of all batteries tends to 0% at the end of discharge. Compared with the traditional battery network balancing results Figure 5 In comparison, the method proposed in the present invention has obvious effect in improving the battery SOC consistency. Fig. 9 It can be seen that the number of switching actions of divided mode balancing is reduced by 2550 times compared with single-cell balancing.

[0073] The mode-based balancing method proposed in the present invention can not only achieve complete balancing at the end of discharge, that is, the charge states of all batteries are consistent, but also effectively reduce the number of switching actions, improve battery energy utilization and enhance system safety.

[0074] Through the above-mentioned method, the present invention can reconstruct the sub-mode balancing method of the battery network, fully consider the SOC consistency state during the charging and discharging process, and achieve at the end of discharging, improve the balancing efficiency while reducing the impact of the number of switching actions on the system safety.

[0075] This embodiment also provides a system for improving a reconfigurable battery network, including: Initialization unit, configured as: It is used to determine the number of series-parallel battery cells in the reconfigurable battery network according to the load demand, and to build the reconfigurable battery network topology by taking the given runtime output voltage and the system output power as constraints; The balancing unit is configured as: Based on the basic information of the battery cells in the reconfigurable battery network model, the balancing demand of each battery cell is evaluated to obtain an evaluation result; according to the evaluation result, different balancing strategies are established by using balancing indicators, that is, by using the values ​​of the SOC standard deviation and the range of the battery; the balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode; the balancing modes include two balancing modes: single cell balancing and battery pack balancing; The optimization unit is configured as: Used to give a corresponding switch drive signal to the reconfigurable battery network model, and reconfigure the connection between the battery cells based on the balancing strategy; Output unit, configured as: It is used to monitor the voltage, state of charge (SOC) and temperature of the battery cells, and evaluate and adjust the current balancing strategy according to the real-time data; if the balancing strategy reaches the constraint conditions, the balancing monitoring is stopped to obtain an optimized reconfigurable battery network model.

[0076] In another embodiment of the present invention, a computer device is provided, the computer device including a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which are the computing core and control core of the terminal, which are suitable for implementing one or more instructions, and are specifically suitable for loading and executing one or more instructions in a computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the method for improving the reconfigurable battery network.

[0077] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both built-in storage media in a computer device and, of course, extended storage media supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for improving the reconfigurable battery network in the above embodiment.

[0078] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0079] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0080] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0082] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0083] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for improving a reconfigurable battery network, characterized in that: include: According to the load demand, determine the number of series-parallel battery cells in the reconfigurable battery network, take the output voltage and system output power at a given runtime as constraints, and build a reconfigurable battery network model; Based on the basic information of the battery cells in the reconfigurable battery network model, the balancing requirement of each battery cell is evaluated to obtain an evaluation result; according to the evaluation result, different balancing strategies are established by using the balancing index, that is, by using the SOC standard deviation and range value of the battery; The balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode; the balancing mode includes two balancing modes: single cell balancing and battery pack balancing; Giving corresponding switch drive signals to the reconfigurable battery network model, and reconfiguring the connections between the battery cells based on a balancing strategy; Monitor the voltage, state of charge (SOC) and temperature of the battery cells, and evaluate and adjust the current balancing strategy based on real-time data; If the balancing strategy reaches the constraint condition, the balancing monitoring is stopped to obtain an optimized reconfigurable battery network model.

2. The method for improving a reconfigurable battery network according to claim 1, characterized in that: The process of evaluating the balancing requirement of each battery cell based on the basic information of the battery cell in the reconfigurable battery network model is as follows: Testing the open circuit voltage and state of charge SOC reference relationship of the battery unit to obtain the open circuit voltage and state of charge SOC reference relationship curve; Based on the open circuit voltage and state of charge SOC reference relationship curve, the initial voltage and state of charge SOC of all batteries are obtained to obtain the sample standard deviation and range of the state of charge SOC of the battery cells; Compare the sample standard deviation and range of the state of charge (SOC) of the battery cell with a preset threshold value to evaluate the balancing requirement of each battery cell; The reconfigurable battery network adopts a cross-type configuration. The reconfigurable battery network includes a plurality of battery cells arranged in an array. Each of the battery cells is connected in parallel with a bypass switch. A series switch is connected in series between adjacent battery cells in the lateral direction, and a parallel switch is also connected in parallel between adjacent battery cells; Parallel switches are connected in parallel between the adjacent battery cells in the longitudinal direction.

3. The method for improving a reconfigurable battery network according to claim 2, characterized in that: The process of comparing the sample standard deviation and range of the state of charge SOC of the battery cell with the preset threshold value and evaluating the balancing requirement of each battery cell is as follows: In the formula, , is the set standard deviation threshold, , is the set extreme value threshold, is the sample standard deviation, The sample is extremely poor; It is a balancing mode when the battery consistency is good. This is a balancing mode when battery consistency is poor.

4. The method for improving a reconfigurable battery network according to claim 1, characterized in that: The balancing mode includes a multi-battery series-first-parallel-later balancing mode and a single-battery balancing mode; The multi-battery series-first-parallel-later balancing mode is to perform a balancing operation in a series-first-parallel-later manner when the battery consistency is good. The balancing operation is energy transfer between battery groups. The single cell balancing mode is that when the battery consistency is poor, each battery cell performs a balancing operation individually, and a switch device is used to switch between the battery cells multiple times to achieve energy transfer. At this time, the series connection first and then parallel connection changes to parallel connection first and then series connection; The priorities of the balancing modes are: The priority of the balancing mode is selected according to the state of charge of the battery cells. When charging, the battery cells with low power are selected to be charged first, and when discharging, the battery cells with high power are selected to be discharged first; The battery cells are disconnected one by one when they are fully charged or discharged.

5. The method for improving a reconfigurable battery network according to claim 1, characterized in that: The process of determining the number of series-parallel battery cells in the reconfigurable battery network according to the load demand is as follows: Calculate the number of series: Calculate the number of parallel connections: In the formula, is the load voltage, is the load current is the voltage of each battery cell, is the current of each battery cell, is the number of batteries connected in series, is the number of batteries connected in parallel.

6. The method for improving a reconfigurable battery network according to claim 1, characterized in that: The total output voltage and current of the reconfigurable battery network model meet the following requirements with respect to the load required voltage and current: In the formula, , To select the total output voltage and current on the path, , For the load voltage and current that need to be met, the values ​​of v and i are usually very small; The output power constraint of the system is: the output power of the reconfigurable battery network under the selected path must meet the normal operating power of the load: In the formula, is the total power output by the battery topology, Pmin is the minimum power required by the system load, and Pmax is the maximum power that the battery topology can output.

7. The method for improving a reconfigurable battery network according to claim 1, characterized in that: If the balancing strategy reaches the constraint condition, each battery unit of the reconfigurable battery network model is charged to a state of charge SOC=1, and the battery unit is cut off; When each battery cell of the reconfigurable battery network model is discharged to a state of charge SOC=0, the battery cell is cut off; When all battery cells are charged or discharged, the normal battery pack connection state is restored.

8. A system for improving a reconfigurable battery network, characterized in that: The method for improving a reconfigurable battery network according to any one of claims 1 to 7 comprises: Initialization unit, configured as: It is used to determine the number of series-parallel battery cells in the reconfigurable battery network according to the load demand, and to build a reconfigurable battery network model by taking the output voltage and the output power of the system as constraints when given operation; The balancing unit is configured as: Used to evaluate the balancing demand of each battery cell based on the basic information of the battery cell in the reconfigurable battery network model to obtain an evaluation result; according to the evaluation result, using the balancing index, that is, through the SOC standard deviation and range value of the battery, establish different balancing strategies; the balancing strategy includes a balancing mode for each battery cell and a priority of the balancing mode; the balancing mode includes two balancing modes: single cell balancing and battery pack balancing; The optimization unit is configured as: Used to give a corresponding switch drive signal to the reconfigurable battery network model, and reconfigure the connection between the battery cells based on the balancing strategy; Output unit, configured as: It is used to monitor the voltage, state of charge (SOC) and temperature of the battery cells, and evaluate and adjust the current balancing strategy according to the real-time data; if the balancing strategy reaches the constraint conditions, the balancing monitoring is stopped to obtain an optimized reconfigurable battery network model.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for improving a reconfigurable battery network as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method for improving a reconfigurable battery network as described in any one of claims 1 to 7 are implemented.

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