A lifespan protection method and device for a dynamically reconfigurable energy storage system

Abstract

The present application discloses a life protection method and device for a dynamically reconfigurable energy storage system, relating to the field of energy storage in new energy power systems. The method includes: obtaining the state of charge, health state, capacity, and historical cycle count of each battery pack; determining the health coefficient of each battery pack in a weighted manner according to the state of charge and health state of each battery pack; determining the load coefficient of each battery pack in a weighted manner according to the capacity and historical cycle count of each battery pack; calculating the health degree of the dynamically reconfigurable energy storage system by using the health coefficients and load coefficients of each battery pack; and performing life protection on the battery pack according to a preset strategy based on the health degree of the dynamically reconfigurable energy storage system. The present application improves the accuracy of life assessment of the dynamically reconfigurable energy storage system, and further improves the adaptability and accuracy of life protection for the battery pack.

Description

Technical Field

[0001] This application relates to the field of energy storage in new energy power systems, and particularly to a method and device for protecting the lifespan of a dynamically reconfigurable energy storage system. Background Art

[0002] Electric energy storage systems usually adopt a fixed series-parallel connection method. The impact caused by the difference in battery balance becomes more and more significant, and the performance of the entire energy storage system depends on the battery with the worst performance. Since the performance of the batteries in the energy storage system may be inconsistent, after running for a period of time, if the battery balance is not good, the SOH (State of Health) of some battery monomers is significantly lower than the average level, and some batteries will bear more load or deeper discharge, resulting in shortened battery life and increased operation and maintenance costs of the system. The emergence of dynamically reconfigurable energy storage systems has improved the management level of battery monomers. A dynamically reconfigurable energy storage system adopts multiple dynamically reconfigurable battery networks. Each battery network contains multiple battery packs. The battery packs are connected in series and parallel with control switches and bypass switches. By opening / closing the control switches, the battery packs can be removed / connected to the battery network to achieve dynamic reconfiguration of the battery network.

[0003] In some cases, the dynamically reconfigurable energy storage system still has problems such as low accuracy of battery pack evaluation, inadequate lifespan protection measures for battery packs with poor health, and lack of adaptability and pertinence of lifespan protection measures. Summary of the Invention

[0004] The purpose of this application is to provide a method and device for protecting the lifespan of a dynamically reconfigurable energy storage system, which can improve the accuracy of the dynamically reconfigurable energy storage system, and further improve the adaptability and accuracy of lifespan protection for battery packs.

[0005] To achieve the above purpose, the present application provides the following solutions.

[0006] In the first aspect, the present application provides a method for protecting the lifespan of a dynamically reconfigurable energy storage system. The dynamically reconfigurable energy storage system includes multiple independently controllable battery packs. The method for protecting the lifespan of the dynamically reconfigurable energy storage system includes: obtaining the state of charge, health state, capacity, and historical cycle count of each battery pack; determining the health coefficient of each battery pack in a weighted manner according to the state of charge and health state of each battery pack; determining the load coefficient of each battery pack in a weighted manner according to the capacity and historical cycle count of each battery pack; calculating the health degree of the dynamically reconfigurable energy storage system by using the health coefficients and load coefficients of each battery pack; and performing lifespan protection on the battery packs according to a preset strategy based on the health degree of the dynamically reconfigurable energy storage system.

[0007] In a second aspect, the present application provides a computer device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor, where the processor executes the computer program to implement the above-mentioned method for protecting the lifespan of a dynamically reconfigurable energy storage system.

[0008] According to the specific embodiments provided by the present application, the following technical effects are disclosed: By combining the health factor and load factor of each battery pack in the dynamically reconfigurable energy storage system, the present application evaluates the health of the dynamically reconfigurable energy storage system, improving the accuracy of the lifespan evaluation of the dynamically reconfigurable energy storage system. Based on the health of the dynamically reconfigurable energy storage system, a more targeted lifespan protection is carried out on the battery pack according to a preset strategy, improving the adaptability and accuracy of the lifespan protection of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0010] Figure 1 Schematic flowchart of a method for protecting the lifespan of a dynamically reconfigurable energy storage system provided by an embodiment of the present application Figure 1 。

[0011] Figure 2 Schematic flowchart of a method for protecting the lifespan of a dynamically reconfigurable energy storage system provided by an embodiment of the present application Figure 2 。

[0012] Figure 3 Schematic flowchart of a method for protecting the lifespan of a dynamically reconfigurable energy storage system provided by an embodiment of the present application Figure 3 。

[0013] Figure 4 Schematic structural diagram of a computer device provided by an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0015] To make the above objects, features, and advantages of the present application more apparent and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] In an energy storage system for new energy power, the battery is the carrier for storing energy, and the battery life has an important impact on the system operation and maintenance costs. The SOH of the battery reflects the ratio of the current capacity of the battery to the rated capacity and is usually used to evaluate the battery life. It is inevitable that the SOH gradually decreases with the charge and discharge of the battery. DOD (Depth of discharge) will cause great damage to the battery, and maintaining an extremely high or extremely low SOC (State of Charge) for a long time will accelerate the aging of the battery.

[0017] Embodiment 1, as Figures 1 - 3 shown, this embodiment provides a method for protecting the life of a dynamically reconfigurable energy storage system. The dynamically reconfigurable energy storage system includes a plurality of independently controllable battery packs, and the method for protecting the life of the dynamically reconfigurable energy storage system includes.

[0018] S1. Obtain the state of charge, health state, capacity, and historical cycle count of each battery pack.

[0019] S2. Determine the health coefficient of each battery pack in a weighted manner according to the state of charge and health state of each battery pack.

[0020] Further, step S2 specifically includes.

[0021] S21. Calculate the charge weight factor of each battery pack according to the state of charge of each battery pack.

[0022] Further, the calculation formula for the charge weight factor of each battery pack is as follows.

[0023] .

[0024] Where, is the charge weight factor of the battery pack; is the state of charge of the battery pack; is the minimum state of charge of the target working range of the battery pack; is the maximum state of charge of the target working range of the battery pack.

[0025] Optionally, = 0.2; = 0.8.

[0026] S22. Calculate the health weight factor of each battery pack according to the health state of each battery pack.

[0027] Furthermore, the calculation formula for the health weight factor of each battery pack is as follows.

[0028] 。

[0029] Wherein, is the health weight factor of the battery pack; is the state of health of the battery pack; is the minimum value of the state of health in the target operating range of the battery pack; is the maximum value of the state of health in the target operating range of the battery pack.

[0030] Optionally, = 0.5; = 1.

[0031] S23. Assign weights to the charge weight factor and the health weight factor of each battery pack respectively to determine the health coefficient of each battery pack.

[0032] In the actual application process, is used to characterize the contribution of the current state of charge of the battery pack to the health coefficient; is used to characterize the contribution of the current state of health of the battery pack to the health coefficient.

[0033] Furthermore, the calculation formula for the health coefficient of each battery pack is as follows.

[0034] 。

[0035] Wherein, is the health coefficient of the battery pack; is the charge weight factor of the battery pack; is the health weight factor of the battery pack; is the weight coefficient of the charge weight factor; is the weight coefficient of the health weight factor.

[0036] Optionally, , and can be adjusted according to the application scenario.

[0037] Optionally, ; 。

[0038] S3. Determine the load factor of each battery pack in a weighted manner according to the capacity and historical cycle count of each battery pack.

[0039] Furthermore, the calculation formula for the load factor of each battery pack is as follows.

[0040] 。

[0041] Among them, is the load factor of the battery pack ; is the capacity of the battery pack; is the battery pack historical cycle count; is the weight coefficient of the capacity; is the weight coefficient of the historical cycle count.

[0042] Optionally, ; .

[0043] S4. Using the health factor and load factor of each battery pack, calculate the health degree of the dynamic reconfigurable energy storage system.

[0044] Furthermore, the calculation formula for the health degree of the dynamic reconfigurable energy storage system is as follows.

[0045] .

[0046] Among them, is the health degree of the dynamic reconfigurable energy storage system, is the load factor of the battery pack ; is the health factor of the battery pack ; is the total number of battery packs.

[0047] In the actual application process, ranges from [0, 1], and the closer it is to 1, the better the health condition of the dynamic reconfigurable energy storage system. Using the weighted average value of the health factor of the battery packs to calculate the health factor of the entire dynamic reconfigurable energy storage system can comprehensively evaluate the overall health state of the dynamic reconfigurable energy storage system. Combining the weights can more accurately reflect the impact of each battery pack on the dynamic reconfigurable energy storage system and provide a quantitative basis for the maintenance and optimization of the dynamic reconfigurable energy storage system.

[0048] The following provides a scenario where the health factor of the dynamic reconfigurable energy storage system is too low: When the dynamic reconfigurable energy storage system is charging and running, with the SOH and capacity of each battery pack being constant, the SOC gradually increases (gradually deviates from the value), and the SOC weight factor of each battery pack will also become smaller due to the increase in SOC, remains unchanged, and when the SOH weight factor also remains unchanged, becoming smaller will cause the health factor becomes smaller. When the health factor of each battery pack in the dynamically reconfigurable energy storage system becomes smaller, the overall health factor of the dynamically reconfigurable energy storage system will also become smaller, resulting in a deterioration of the overall health state of the dynamically reconfigurable energy storage system.

[0049] S5. Perform life protection on the battery pack according to a preset strategy based on the health degree of the dynamically reconfigurable energy storage system.

[0050] Furthermore, the preset strategy specifically includes.

[0051] 1) When the health degree of the dynamically reconfigurable energy storage system is greater than or equal to the first threshold and less than or equal to the second threshold, do not process the battery pack.

[0052] 2) When the health degree of the dynamically reconfigurable energy storage system is greater than or equal to the third threshold and less than the second threshold, update the target power of the dynamically reconfigurable energy storage system according to the health degree of the dynamically reconfigurable energy storage system, and perform dynamic reconfiguration on the battery pack based on the target power.

[0053] Furthermore, the calculation formula for the target power of the dynamically reconfigurable energy storage system is as follows.

[0054] .

[0055] Among them, is the updated target power of the dynamically reconfigurable energy storage system; is the historical target power of the dynamically reconfigurable energy storage system; is the health degree of the dynamically reconfigurable energy storage system.

[0056] 3) When the health degree of the dynamically reconfigurable energy storage system is greater than or equal to the fourth threshold and less than the third threshold, replace the target battery pack; the target battery pack is a battery pack with a health factor greater than or equal to the first threshold and less than the second threshold; the second threshold is greater than the first threshold; the first threshold is greater than the third threshold; the third threshold is greater than the fourth threshold.

[0057] In the actual application process, the operation process of the preset strategy is as follows.

[0058] 1) When 0.8 ≤ <1, the health condition of the dynamically reconfigurable energy storage system is good, and no life protection is required (no calculation of the target power is required, nor is dynamic reconfiguration of the battery pack required).

[0059] 2) When 0.5 ≤ When <0.8, the health condition of the dynamic reconfigurable energy storage system is average. The system needs to recalculate the target power and perform dynamic reconfiguration on the battery pack (indicating that under the current operating state, the overall health coefficient of the battery pack is too low. At this time, it is necessary to recalculate the target power of the dynamic reconfigurable energy storage system, the system issues a new target power, and performs dynamic reconfiguration of the battery pack). Specifically, after the dynamic reconfigurable energy storage system receives the updated target power, it is sent to each battery pack (energy storage unit), and each battery pack is dynamically reconfigured according to the previously calculated health coefficient of each battery pack , and perform dynamic reconfiguration on the battery pack.

[0060] 3) When ≤0.5, the health condition of the dynamic reconfigurable energy storage system is poor, and the target battery pack needs to be replaced.

[0061] Next, take the dynamic reconfigurable energy storage system of a 3-parallel and 14-series battery network as an example to further illustrate the actual process of the life protection of the dynamic reconfigurable energy storage system.

[0062] 1. When the system health coefficient is in the range of 0.8 ≤ < 1, perform rated power (three out of three) charge and discharge.

[0063] 2. When the system health coefficient drops to the range of 0.5 ≤ <0.8, perform 2 / 3 rated power charge and discharge, and the battery network performs "three out of two" reconfiguration, that is, based on the technical base of the dynamic reconfigurable energy storage system, according to the health coefficient of each battery pack, select 2 battery packs (with higher health coefficients) from every 3 battery packs to operate, and the other 1 battery pack is removed from the battery network (this belongs to the content of dynamic reconfiguration, and access and removal are controlled by opening and closing the circuit breaker). In this way, it is dynamically reconfigured into a 2-parallel and 14-series energy storage system that performs charge and discharge at 2 / 3 rated power. By calculating the system health coefficient and the battery pack health coefficient in real time and continuously repeating the dynamic reconfiguration process of the battery network, the goal of protecting the battery life is achieved.

[0064] 3. When the system health coefficient ≤0.5, replace the target battery pack.

[0065] The technical effects of the present application are as follows: By combining the health factor and the load factor of each battery pack in the dynamic reconfigurable energy storage system, the present application evaluates the health of the dynamic reconfigurable energy storage system, improving the accuracy of the life evaluation of the dynamic reconfigurable energy storage system. Based on the health of the dynamic reconfigurable energy storage system, a more targeted life protection is carried out on the battery pack according to a preset strategy. When the health is good, no treatment is performed; when the health is average, a reasonable target power is recalculated and the battery pack is dynamically reconfigured; when the health is poor, a new battery pack is replaced. This enables the battery packs in better condition to undertake more charge and discharge tasks, reducing the burden on the aging battery packs and making the SOH of all battery packs in the energy storage system tend to be balanced, improving the adaptability and accuracy of the life protection of the battery packs, thereby achieving the goals of protecting the battery life and reducing the operation and maintenance costs of the energy storage system.

[0066] Embodiment 2. The present application also provides a computer device, which can be a server or a terminal, and its internal structure diagram can be as Figure 4 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store and process data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, the above-mentioned various methods are implemented.

[0067] Those skilled in the art can understand that Figure 4 the structure shown in

[0068] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0069] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0070] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for protecting the lifespan of a dynamically reconfigurable energy storage system, the dynamically reconfigurable energy storage system comprising a plurality of independently controllable battery packs, characterized in that, The life protection method of the dynamic reconfigurable energy storage system includes: Obtaining the state of charge, health state, capacity, and historical cycle count of each battery pack; Determining the health coefficient of each battery pack in a weighted manner according to the state of charge and health state of each battery pack, specifically including: calculating the charge weight factor of each battery pack according to the state of charge of each battery pack; calculating the health weight factor of each battery pack according to the health state of each battery pack; weighting the charge weight factor and health weight factor of each battery pack respectively to determine the health coefficient of each battery pack; the calculation formula for the charge weight factor of each battery pack is as follows: ； Among them, is the charge weight factor of the battery pack; is the state of charge of the battery pack; is the minimum state of charge of the target operating range of the battery pack; is the maximum state of charge of the target operating range of the battery pack; The calculation formula for the health weight factor of each battery pack is as follows: ； Among them, is the health weight factor of the battery pack; is the state of health of the battery pack; is the minimum value of the state of health of the target operating range of the battery pack; is the maximum value of the state of health of the target operating range of the battery pack; The calculation formula for the health coefficient of each battery pack is as follows: ； wherein, is the health coefficient of the battery pack; is the state of charge weight factor of the battery pack; is the health weight factor of the battery pack; is the weight coefficient of the state of charge weight factor; is the weight coefficient of the health weight factor; Determining the load coefficient of each battery pack in a weighted manner according to the capacity and historical cycle count of each battery pack; the calculation formula for the load coefficient of each battery pack is as follows: ； Among them, is the load factor of the battery pack ; is the capacity of the battery pack ; is the historical cycle number of the battery pack ; is the weight coefficient of the capacity Calculating the health degree of the dynamic reconfigurable energy storage system by using the health coefficients and load coefficients of each battery pack; the calculation formula for the health degree of the dynamic reconfigurable energy storage system is as follows: ； Among them, is the health degree of the dynamic reconfigurable energy storage system, is the load factor of the battery pack , is the health factor of the battery pack , is the total number of battery packs; Based on the health degree of the dynamic reconfigurable energy storage system, performing life protection on the battery packs according to a preset strategy; the preset strategy specifically includes: when the health degree of the dynamic reconfigurable energy storage system is greater than or equal to the first threshold and less than or equal to the second threshold, no processing is performed on the battery packs; when the health degree of the dynamic reconfigurable energy storage system is greater than or equal to the third threshold and less than the first threshold, according to the health degree of the dynamic reconfigurable energy storage system, updating the target power of the dynamic reconfigurable energy storage system, and performing dynamic reconfiguration on the battery packs based on the target power, performing charge and discharge at 2 / 3 of the rated power, and the battery network performs "two out of three" reconfiguration, that is, based on the dynamic reconfigurable energy storage system technology, according to the magnitude of the health coefficient of each battery pack, 2 out of every 3 battery packs are selected to operate, and the other 1 battery pack is removed from the battery network and charged and discharged at 2 / 3 of the rated power, and the system health coefficient and battery pack health coefficient are calculated in real time, and the dynamic reconfiguration process of the battery network is continuously repeated; when the health degree of the dynamic reconfigurable energy storage system is greater than or equal to the fourth threshold and less than the third threshold, replacing the target battery pack; the target battery pack is the battery pack with a health coefficient greater than or equal to the first threshold and less than the second threshold; the second threshold is greater than the first threshold; the first threshold is greater than the third threshold; the third threshold is greater than the fourth threshold.

2. The method for protecting the lifespan of the dynamically reconfigurable energy storage system according to claim 1, characterized in that, The calculation formula for the target power of the dynamic reconfigurable energy storage system is as follows: ； Wherein, is the target power of the updated dynamic reconfigurable energy storage system; is the target power of the historical dynamic reconfigurable energy storage system; is the health of the dynamic reconfigurable energy storage system.

3. A computer device, comprising: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to implement the life protection method of the dynamic reconfigurable energy storage system according to any one of claims 1-2.

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