A method and control system for balancing energy storage systems

Abstract

This application provides a method and control system for equalizing an energy storage system. The method includes: sampling data from each energy storage cell; processing the data to obtain a reference voltage and calculating the difference ΔU between each energy storage cell and the reference voltage; setting a comparison voltage U1; when ΔU >= U1, a passive equalization circuit is activated to discharge the energy storage cell; when ΔU <= -U1, an active equalization circuit is activated to charge the energy storage cell. This application determines whether equalization is needed based on the difference between each energy storage cell and the reference voltage, enabling real-time dynamic adjustment. Through passive equalization during overvoltage and active equalization during undervoltage, the voltage consistency of each energy storage cell can be improved, thereby increasing the overall charging and discharging efficiency and extending the service life of the energy storage cells.

Description

Technical Field

[0001] This invention relates to energy storage unit management technology, and more particularly to an energy storage system balancing method and control system. Background Technology

[0002] Energy storage systems consist of multiple energy storage cells (such as batteries or supercapacitors) connected in series. Due to inherent inconsistencies in voltage, capacity, and internal resistance among these cells during manufacturing and use, one or more cells in a series connection will always charge or discharge at faster or slower rates than the others, resulting in inconsistencies. These inconsistencies affect the overall charging and discharging efficiency of the system, and as these inconsistencies are amplified during use, they accelerate the performance degradation of some cells, ultimately impacting their lifespan. Summary of the Invention

[0003] The purpose of this invention is to provide an energy storage system balancing method and control system that can maintain good consistency among individual energy storage cells.

[0004] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0005] According to a first aspect of the present invention, an energy storage system balancing method is provided, comprising:

[0006] Data sampling is performed on each individual energy storage unit;

[0007] The data is processed to obtain the reference voltage, and the difference ΔU between each energy storage cell and the reference voltage is calculated.

[0008] Set the comparison voltage U1;

[0009] When ΔU>=U1, the passive equalization circuit is turned on to discharge the energy storage cells;

[0010] When ΔU <= -U1, the active balancing circuit is turned on to charge the energy storage cells.

[0011] In one embodiment, the method further includes:

[0012] Set the hysteresis value U2;

[0013] When ΔU>=U1-U2, the passive equalization circuit is turned on to discharge the energy storage cells;

[0014] When ΔU <= -(U1-U2), the passive equalization circuit is turned on to discharge the energy storage cells.

[0015] In one embodiment, the method further includes:

[0016] When ΔU>=U1-U2, the overvoltage balance flag is set to 1, and the undervoltage flag is cleared to 0;

[0017] When ΔU <= -(U1-U2), the undervoltage balance flag is set to 1, and the overvoltage balance flag is cleared to 0;

[0018] When -(U1-U2)<=ΔU<=U1-U2, both the overvoltage balance flag and the undervoltage balance flag are cleared to 0.

[0019] In one embodiment, the method further includes:

[0020] Determine the operating status of the energy storage system;

[0021] When the energy storage system is in a static state, U1 is set to the first set value;

[0022] When the energy storage system is in a charging / discharging state, U1 is set to the second set value;

[0023] The first setting value is less than the second setting value.

[0024] In one embodiment, the method further includes:

[0025] When the energy storage system is in a static state, set U2 to the third set value;

[0026] When the energy storage system is in a charging / discharging state, U2 is set to the fourth set value;

[0027] The third setting value is less than the fourth setting value.

[0028] In one embodiment, the reference voltage in the method is the average of the voltages of each individual energy storage cell.

[0029] According to a second aspect of the present invention, an energy storage system balancing method is provided, comprising:

[0030] Data sampling is performed on each individual energy storage unit;

[0031] The data is processed to obtain the reference voltage, and the difference ΔU between each energy storage cell and the reference voltage is calculated; the comparison voltage U1 and the hysteresis value U2 are set.

[0032] Determine if the overpressure equalization flag is 1;

[0033] When the current overvoltage equalization flag is 1, determine whether ΔU >= U1 - U2;

[0034] When ΔU ≥ U1 - U2, the overvoltage balance flag bit remains unchanged, the undervoltage balance flag bit is cleared to 0, and the passive balance circuit is turned on;

[0035] When ΔU < U1 - U2, the overvoltage balance flag bit is cleared to 0, and the passive balance circuit is turned off;

[0036] When the current overvoltage balance flag bit is not 1, it is judged whether the previous undervoltage balance flag bit is 1;

[0037] When the current undervoltage balance flag bit is 1, it is judged whether ΔU ≥ U1;

[0038] When ΔU ≥ U1, the overvoltage balance flag bit is set to 1, the undervoltage balance flag bit is cleared to 0, and the passive balance circuit is turned on;

[0039] When ΔU < U1, it is judged whether ΔU ≤ -U1;

[0040] If ΔU ≤ -U1, the undervoltage balance flag bit is set to 1, the overvoltage balance flag bit is cleared to 0, and the active balance circuit is turned on;

[0041] If ΔU > -U1, both the overvoltage balance flag bit and the undervoltage balance flag bit remain unchanged;

[0042] When the current undervoltage balance flag bit is not 1, it is judged whether ΔU ≤ -(U1 - U2);

[0043] If ΔU ≤ -(U1 - U2), the undervoltage balance flag bit remains unchanged, the overvoltage balance flag bit is cleared to 0, and the active balance circuit is turned on;

[0044] If ΔU > -(U1 - U2), the undervoltage balance flag bit is cleared to 0, and the active balance circuit is turned off.

[0045] In an embodiment, before setting the comparison voltage U1 and the hysteresis value U2, the method further includes:

[0046] Judging whether the operating state of the energy storage system is static;

[0047] If it is in the static state, set the comparison voltage U1 to the first set value and the hysteresis value U2 to the third set value;

[0048] If it is not in the static state, set the comparison voltage U1 to the second set value and the hysteresis value U2 to the fourth set value.

[0049] According to a third aspect of the present invention, a control system for performing any of the above-described energy storage system balancing methods is provided, comprising an energy storage module, a sampling module, a passive balancing module, an active balancing module, a power supply, an MCU, a main controller, and a host computer; the energy storage module comprises multiple energy storage cells; the sampling module, the passive balancing module, and the active balancing module are all connected to the energy storage module; the sampling module is signal-connected to the MCU, the host computer is signal-connected to the main controller, the main controller is signal-connected to the MCU, the MCU is connected to the active balancing module, and the power supply is connected to both the active balancing module and the MCU.

[0050] In one embodiment, the passive balancing module discharges the energy storage cell by consuming energy through resistance; the active balancing module charges the energy storage cell by charging it with a power source.

[0051] The beneficial effects of this invention are: by determining whether equalization is needed by the difference between each energy storage cell and the reference voltage, real-time dynamic adjustment can be achieved; by passive equalization during overvoltage and active equalization during undervoltage, the voltage consistency of each energy storage cell can be improved, thereby improving the overall charging and discharging efficiency and extending the service life of the energy storage cells. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0053] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0054] Figure 1 This is a flowchart illustrating an embodiment of the method of this application;

[0055] Figure 2 This is a schematic diagram showing the relationship between the voltage values ​​in this application;

[0056] Figure 3 This is a schematic diagram of the modules in an embodiment of the system of this application. Detailed Implementation

[0057] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. Note that the aspects described below in conjunction with the accompanying drawings and specific embodiments are merely exemplary and should not be construed as imposing any limitation on the protection scope of the present invention.

[0058] As Figure 1 shown, an embodiment of the present application provides an energy storage system balancing method, including:

[0059] Step 100: Power on the system and perform data sampling on each energy storage monomer;

[0060] Step 200: Process the data, calculate the mean value as the reference voltage, and calculate the difference ΔU between each energy storage monomer and the reference voltage;

[0061] Step 300: Judge the operating state of the energy storage system to determine whether it is in a static state;

[0062] Step 310: If it is in a static state, compare the voltage U1 to be 30 mV and the hysteresis value U2 to be 10 mV.

[0063] Step 320: If it is not in a static state, compare the voltage U1 to be 50 mV and the hysteresis value U2 to be 15 mV.

[0064] Step 400: Judge whether the previous overvoltage balance flag bit is 1;

[0065] When the current overvoltage balance flag bit is 1, perform Step 500: Judge whether ΔU >= U1 - U2;

[0066] When ΔU >= U1 - U2, perform Step 510: Keep the overvoltage balance flag bit unchanged, clear the undervoltage balance flag bit, and turn on the passive balance circuit;

[0067] When ΔU < U1 - U2, perform Step 520: Clear the overvoltage balance flag bit and turn off the passive balance circuit.

[0068] When the current overvoltage balance flag bit is not 1, perform Step 600: Judge whether the previous undervoltage balance flag bit is 1;

[0069] When the current undervoltage balance flag bit is 1, perform Step 700: Judge whether ΔU >= U1. When ΔU >= U1, perform Step 710: Set the overvoltage balance flag bit to 1, clear the undervoltage balance flag bit, and turn on the passive balance circuit;

[0070] When ΔU < U1, perform Step 720: Judge whether ΔU <= -U1,

[0071] If ΔU <= -U1, perform Step 721: Set the undervoltage balance flag bit to 1, clear the overvoltage balance flag bit, and turn on the active balance circuit;

[0072] If ΔU>-U1, proceed to step 722, and both the overvoltage balance flag and the undervoltage balance flag remain unchanged;

[0073] If the current undervoltage equalization flag is not 1, proceed to step 800 and determine whether ΔU <= -(U1-U2);

[0074] If ΔU <= -(U1-U2), proceed to step 810: the undervoltage equalization flag remains unchanged, the overvoltage equalization flag is cleared to 0, and the active equalization circuit is turned on.

[0075] If ΔU>-(U1-U2), proceed to step 820: clear the undervoltage equalization flag to 0 and turn off the active equalization circuit.

[0076] It should be noted that in step 200 above, the reference voltage can be the average voltage of each energy storage unit, or other values ​​that can measure the overall voltage level, such as the median. The reference voltage is dynamic and changes with the voltage values ​​of each energy storage unit; therefore, this method achieves a dynamic equilibrium.

[0077] In step 300 above, when the energy storage system is in a non-static state, it may be in a charging state or a discharging state.

[0078] When the energy storage system is in a quiescent state, the difference between each energy storage unit and the reference voltage should be smaller than the difference between each energy storage unit and the reference voltage when it is charging or discharging. Therefore, the comparison voltage U1 and the hysteresis value are smaller in the quiescent state. In other words, the consistency requirements of each energy storage unit in the quiescent state are higher.

[0079] The overvoltage balancing flag and undervoltage balancing flag in steps 400 and 600 above refer to their values ​​after the previous execution of this method. This method is executed cyclically according to a set period. Whether the energy storage unit was in an overvoltage or undervoltage state during the previous execution affects the subsequent execution. A pre-overvoltage balancing flag of 1 indicates that the energy storage unit was in an overvoltage state during the previous execution of this method, and the passive balancing circuit is on. A pre-overvoltage balancing flag of 0 indicates that the energy storage unit was not in an overvoltage state during the previous execution of this method, and the passive balancing circuit is off. A pre-undervoltage balancing flag of 1 indicates that the energy storage unit was in an undervoltage state during the previous execution of this method, and the active balancing circuit is on. A pre-undervoltage balancing flag of 0 indicates that the energy storage unit was in an undervoltage state during the previous execution of this method, and the active balancing circuit is on.

[0080] In this application, passive balancing refers to balancing that releases excess energy, such as through resistor methods or Zener diode methods. Active balancing refers to balancing that actively replenishes insufficient energy storage units, such as through charging via an external power source.

[0081] like Figure 2 As shown, after the above equalization method, when the energy storage unit Ui is equal to the reference voltage... The difference between When the range exceeds U1-U2, passive balancing will occur. When the value is below -(U1-U2), active balancing will be performed.

[0082] Corresponding to the methods described above, embodiments of this application also provide a control system, such as... Figure 3 As shown, the system includes an energy storage module 31, a sampling module 32, a passive balancing module 33, an active balancing module 34, a power supply 35, an MCU (microcontroller) 36, a main controller 37, and a host computer 38.

[0083] The energy storage module 31 comprises multiple individual energy storage units, which can be either a series-connected battery pack or a supercapacitor. The sampling module 32, passive balancing module 33, and active balancing module 34 are all connected to the energy storage module 31. The sampling module 32 is connected to the MCU 36 via interfaces such as SPI. The host computer 38 is connected to the main controller 37. The main controller 37 is connected to the MCU 36 via CAN, RS-485, Ethernet, WIFI, etc. The MCU 36 is connected to the active balancing module 34, and the power supply 35 is connected to both the active balancing module 34 and the MCU 36.

[0084] In this embodiment, the passive balancing module 33 discharges the energy storage cells by consuming energy through resistors; the active balancing module 34 charges the energy storage cells by charging them with a power source. Both passive and active balancing can be achieved using existing circuit structures, so they will not be described in detail here.

[0085] In summary, this application determines whether equalization is needed by measuring the difference between each energy storage cell and the reference voltage, enabling real-time dynamic adjustment. Through passive equalization during overvoltage and active equalization during undervoltage, it can improve the voltage consistency of each energy storage cell, thereby improving the overall charging and discharging efficiency and extending the service life of the energy storage cells.

[0086] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0087] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0088] The above description is merely a preferred example of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A method for balancing energy storage systems, characterized in that, Comprising: Performing data sampling on each energy storage monomer; Processing the data to obtain a reference voltage and calculating the difference ΔU between each energy storage monomer and the reference voltage; Setting a comparison voltage U1; When ΔU >= U1, the passive equalization circuit conducts to discharge the energy storage monomer; When ΔU <= -U1, the active equalization circuit conducts to charge the energy storage monomer; Setting a hysteresis value U2; when ΔU >= U1 - U2, the passive equalization circuit conducts to discharge the energy storage monomer; when ΔU <= -(U1 - U2), the passive equalization circuit conducts to discharge the energy storage monomer; When ΔU >= U1 - U2, set the overvoltage equalization flag bit to 1 and clear the undervoltage flag bit; when ΔU <= -(U1 - U2), set the undervoltage equalization flag bit to 1 and clear the overvoltage equalization flag bit; when -(U1 - U2) <= ΔU <= U1 - U2, clear both the overvoltage equalization flag bit and the undervoltage equalization flag bit.

2. The energy storage system balancing method according to claim 1, characterized in that, Also comprising: Judging the operating state of the energy storage system; When the energy storage system is in a static state, setting U1 to a first set value; When the energy storage system is in a charge / discharge state, setting U1 to a second set value; The first set value is less than the second set value.

3. The energy storage system balancing method according to claim 2, characterized in that, Also comprising: When the energy storage system is in a static state, setting U2 to a third set value; When the energy storage system is in a charge / discharge state, setting U2 to a fourth set value; The third set value is less than the fourth set value.

4. The energy storage system balancing method according to claim 1, characterized in that, The reference voltage is the average value of the voltages of each energy storage monomer.

5. A method for balancing an energy storage system, characterized in that, Comprising: Performing data sampling on each energy storage monomer; Processing the data to obtain a reference voltage, calculating the difference ΔU between each energy storage monomer and the reference voltage; setting a comparison voltage U1 and a hysteresis value U2; Judging whether the previous overvoltage equalization flag bit is 1; When the previous overvoltage equalization flag bit is 1, judging whether ΔU >= U1 - U2; When ΔU >= U1 - U2, the overvoltage equalization flag bit remains unchanged, the undervoltage equalization flag bit is cleared, and the passive equalization circuit conducts; When ΔU < U1 - U2, the overvoltage equalization flag bit is cleared and the passive equalization circuit is turned off; [[ID= ​ ​ ​ ​ ​ ​ ​ 6. The energy storage system balancing method according to claim 5, characterized in that, ​ ​ If the system is in a static state, set the comparison voltage U1 to the first set value and the hysteresis value U2 to the third set value; if the system is not in a static state, set the comparison voltage U1 to the second set value and the hysteresis value U2 to the fourth set value.

7. A control system for performing the energy storage system balancing method as described in any one of claims 1 to 6, characterized in that: The system includes an energy storage module, a sampling module, a passive balancing module, an active balancing module, a power supply, an MCU, a main controller, and a host computer. The energy storage module comprises multiple energy storage units. The sampling module, passive balancing module, and active balancing module are all connected to the energy storage module. The sampling module is connected to the MCU via signal transmission. The host computer is connected to the main controller via signal transmission. The main controller is connected to the MCU via signal transmission. The MCU is connected to the active balancing module. The power supply is connected to both the active balancing module and the MCU.

8. The control system according to claim 7, characterized in that: The passive balancing module discharges the energy storage cells by consuming energy through resistance; the active balancing module charges the energy storage cells by charging them with a power source.

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