A UPS system and a method for estimating the remaining power of a battery pack of the UPS system

Abstract

The present invention provides a UPS system, including a box body, the rear side of the box body is a U-shaped bracket; a battery pack station is arranged in the front middle part of the box body, and a battery pack is fixedly installed in the battery pack station; an energy storage component is also arranged in the box body; the present invention also provides a method for estimating the remaining power of the battery pack of the UPS system, including the following steps: detecting and obtaining the battery parameter information of multiple single lithium batteries in the battery pack, and estimating the battery SOH value; correcting the initial capacity value of the battery; obtaining the sampled current value of the battery pack for integral calculation to obtain the charge change of the battery pack; judging the battery charging and discharging state and correcting the charge change; iteratively calculating and outputting the SOC estimation value. The present invention has stable connection, high safety performance, good heat dissipation performance, and can realize the measurement of various performance parameters of the battery, so as to achieve the purpose of monitoring the performance state of the battery pack. At the same time, the UPS system described in the present invention has stable connection, high safety performance, and good heat dissipation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of uninterruptible power supply, and in particular to a UPS system and a method for estimating the remaining power of a battery pack of the UPS system. Background Art

[0002] UPS (Uninterruptible Power System / Uninterruptible Power Supply), also known as uninterruptible power supply, is a system device that connects a battery (lead-acid battery or lithium battery) to a host and converts direct current into municipal electricity through modular circuits such as a host inverter. It is mainly used to provide a stable and uninterrupted power supply to a single computer, a computer network system or other power electronic precision equipment.

[0003] The main problems existing in existing UPS systems are as follows: (1) Existing UPS systems are generally fully enclosed, with small internal equipment layout space and compact equipment layout. Since the battery pack generates a large amount of heat during the charging and discharging process, if the heat is difficult to dissipate for a long time, it will cause damage to the internal equipment of the UPS system. How to reasonably layout the electrical equipment inside and outside the UPS system and reasonably dissipate heat is an important issue that needs to be considered in the design of the UPS system; (2) After most of the existing UPS systems are put into use, there is a lack of post-maintenance and management. The UPS system is prone to battery pack abnormalities such as battery pack overcurrent, single cell overvoltage, single cell undervoltage, battery pack total voltage difference is too large, and remaining power is too low. This greatly affects the battery life of the UPS system. Therefore, how to detect the battery pack performance parameters of the UPS system and estimate the SOC and SOH of the battery pack, and use this data to monitor the battery pack status to ensure that the UPS system is in a stable, safe and reliable working state, is a problem that needs to be solved. Summary of the invention

[0004] The present invention provides a UPS system, which can not only reasonably arrange various components in the UPS system within a small space of the UPS, but also has stable connection, high safety performance, good heat dissipation performance, and can also realize pre-charging control and charging and discharging control of a battery pack.

[0005] The technical solution of the present invention is as follows:

[0006] A UPS system includes a square box, a battery pack station is arranged in the box, and one or more battery packs are fixedly installed in the battery pack station; a U-shaped bracket is fixedly installed on the rear side of the box, and the U-shaped bracket is arranged parallel to the rear side of the box with its U-shaped opening facing rearward;

[0007] A U-shaped bracket is fixedly installed on the rear side of the box body. The U-shaped bracket is arranged parallel to the rear side of the box body and its U-shaped opening faces the rear. A battery pack station is set in the front middle of the box body; an energy storage component is also set in the box body, and the energy storage component includes:

[0008] UPS positive and negative busbars, the UPS charging and discharging positive busbars are connected to the main relay, and the two ends of the main relay are also connected in parallel with the pre-charging relay. The main relay and the pre-charging relay are fixedly installed on the right end between the upper and lower side walls of the U-shaped bracket. One end of the UPS positive and negative busbars is the charging and discharging port, which is set on the right side of the box;

[0009] One or more battery packs are fixedly installed on the battery pack station. One or more battery groups connected in series in the battery pack have their negative poles connected to the main negative terminal of the battery pack, and their positive poles are connected in series with a fuse and then connected to the main positive terminal of the battery pack through a relay. The main positive and negative terminals of the battery pack are connected to the positive and negative bus bars of the UPS through the positive and negative bus bars of the battery pack.

[0010] One or more battery detection modules, which are arranged in the battery pack and are provided with a voltage sampling terminal, a current sampling terminal and a CAN communication port. The battery detection module is connected in parallel to the positive and negative terminals of the battery pack through the voltage sampling terminal and is connected to the Hall sensor through the current sampling terminal, and is communicatively connected to the battery management module through the CAN communication port; the battery detection module is used to perform real-time battery performance detection on the battery pack, obtain battery parameter information, and perform real-time SOC estimation and SOH estimation on the battery according to the battery parameter information, and transmit the real-time SOC estimation data, SOH estimation data and real-time battery parameter information to the battery management module;

[0011] The battery management module is arranged in the box and fixedly installed at the bottom of the U-shaped bracket, and is provided with a main relay control terminal and a pre-charge relay control terminal. The main relay control terminal is connected to the main relay in communication, and the pre-charge relay control terminal is connected to the pre-charge relay in communication. The battery management module is also connected to the inverter in communication through the RS485 communication interface, and is connected to the battery detection module through the CAN communication interface; the battery management module is used to perform pre-charge control and charge and discharge control on the battery pack according to the SOC real-time estimation data, the SOH estimation data and the real-time battery parameter information;

[0012] The DC power supply module is fixedly installed at the left end between the upper and lower side walls of the U-shaped bracket, and is electrically connected to the battery pack, battery management module, and battery detection module respectively, so as to provide power for the battery management module and the battery detection module.

[0013] Furthermore, the UPS system receives a charging enable control signal from the inverter, receives battery parameter information, battery pack SOC and SOH real-time estimation data through the battery management module, controls the battery detection module to close the slave relay and pre-charge the battery pack.

[0014] Furthermore, the UPS system receives the charge and discharge enable control signal of the inverter through the battery management module. When there is no battery pack fault in the battery pack and the charging start conditions are met, the main relay is closed to control the battery pack to enter the charging mode. When the battery pack does not meet the charging start conditions, the battery pack is controlled to enter the discharging mode.

[0015] Furthermore, a battery pack fixing base is provided on the battery pack station, a cooling fan is provided on the right side surface of the box body, and a cooling hole is provided on the left side of the box body.

[0016] The present invention also provides a method for estimating the remaining power of a battery pack of a UPS system, which can measure various performance parameters of the UPS system battery, and perform SOC estimation and SOH estimation on the battery pack in the UPS system, so as to achieve the purpose of monitoring the performance status of the battery pack. This is beneficial to preventing the UPS system from experiencing battery pack abnormalities such as battery pack overcurrent, single cell overvoltage, single cell undervoltage, excessive total voltage difference of the battery pack, and too low remaining power.

[0017] The method for estimating the remaining power of a battery pack of a UPS system of the present invention has the following technical solutions:

[0018] A method for estimating the remaining power of a battery pack of a UPS system comprises the following steps:

[0019] The battery detection module detects and obtains the battery parameter information of multiple single-cell lithium batteries in the battery pack, and estimates and obtains the battery SOH value. The battery parameter information includes the battery initial voltage V and the battery nominal capacity C;

[0020] According to the above battery performance data, the battery detection module estimates the initial capacity value E of the battery through the OCV-SOC curve. soc_k-1 , and correct the initial capacity value of the battery in combination with the temperature correction factor and the battery SOH value, and correct the actual discharge capacity value C according to the temperature correction factor n_I (T, S, age);

[0021] The battery detection module samples the sampling resistor through the differential isolation sampling circuit within the sampling period T and obtains the sampling current value i of the battery pack for integral calculation to obtain the charge change ΔQ of the battery pack. i , and its calculation formula is:

[0022] The battery detection module determines the battery charging and discharging status and corrects the charge change;

[0023] According to the SOC initial capacity value and the corrected charge change, the battery detection module iteratively calculates and outputs the SOC estimated value at time k, where the SOC initial capacity value is the iterative variable, and the SOC estimated value at the previous time k-1 is used as the SOC initial capacity value at the next time k. The calculation formula of the SOC estimated value is: Among them, C n_I (T,S,age) is the nominal capacity of the nth battery.

[0024] Furthermore, the battery detection module determines the battery charging and discharging status and calculates the charge change ΔQ i Make corrections, including:

[0025] The battery detection module determines the charge and discharge status of multiple lithium-ion batteries in the battery pack;

[0026] If the battery detection module determines that it is in a high current discharge state, the charge change ΔQ is calculated using the Peukert coefficient. i Correction, the correction formula is ΔQ i =i P t, where i is the sampling current value, t is the ambient temperature of the battery pack, and P is the Peukert coefficient;

[0027] If the battery detection module determines that it is in a charging state, the charge change is corrected by the coulomb efficiency. The correction formula is ΔQ i =η(i,mode)ΔQ′ i , where i is the sampled current value, t is the ambient temperature of the battery pack, and η(i,mode) is the coulomb efficiency.

[0028] Furthermore, the initial capacity value E is estimated by the OCV-SOC curve. soc_k-1 Previously, it also included:

[0029] The battery detection module tests multiple single-cell lithium batteries through a battery testing system and obtains the charge and discharge curves of the multiple single-cell lithium batteries;

[0030] The battery detection module makes real-time corrections to the actual battery capacity when the battery is fully charged or empty.

[0031] According to the charge and discharge curve, the battery detection module continuously records the actual capacity value of the battery at each stage and each voltage platform, and uses the data fitting method to continuously correct the OCV-SOC curve through online self-learning.

[0032] Further, estimating and obtaining the battery SOH value includes the following steps:

[0033] The battery detection module obtains the real-time discharge amount during discharge, the discharge amount at the last moment, the ambient temperature record value, and the number of discharges n, calculates the depth of discharge DOD and the average ambient temperature t, and further calculates the cycle life value A(x)*B(t) of the single cell;

[0034] The battery detection module estimates the SOH of the single battery, and the estimation formula is:

[0035] The present invention arranges a battery pack station in the front middle part of a box body, the battery pack is fixedly installed on the battery pack station through a battery pack fixing base, and a battery group and a battery detection module are fixedly installed in the battery pack; at the same time, a U-shaped bracket is fixedly installed on the rear side surface of the box body, a DC power supply module, a main relay and a pre-charging relay are fixedly installed in the U-shaped bracket, a battery management module is fixedly installed on the outer side of the bottom surface of the U-shaped bracket and located at the rear part of the box body, the positive and negative busbars of the UPS are respectively connected to the main relay and the pre-charging relay, and the charging and discharging ports thereof are installed on the right side surface of the box body of the UPS system, thereby realizing a reasonable layout of the UPS system.

[0036] The present invention provides a cooling fan on the right side surface of the box body, a cooling hole on the left side of the box body, and a heat sink in the battery pack. The heat is transferred to the box body through the heat sink, thereby achieving heat dissipation inside the UPS in a compact layout and a small space in the box body. The heat dissipation effect is good and the normal operation of various circuit devices of the UPS system can be guaranteed.

[0037] The present invention also detects and obtains battery parameter information and estimates and obtains the battery SOH value through a battery detection module. According to the above battery performance data, the battery detection module estimates the battery initial capacity value E soc_k-1 Then, the sampling resistor is sampled and the sampling current value i of the battery pack is obtained for integral calculation to obtain the charge change ΔQ of the battery pack. i ; Finally, according to the SOC initial capacity value and the corrected charge change ΔQ i , iteratively calculates and outputs the estimated SOC value at time k, thereby realizing the measurement of various performance parameters of the UPS system battery, battery SOC estimation and SOH estimation, and achieving the purpose of monitoring the performance status of the battery pack. This is conducive to preventing the UPS system from experiencing battery pack overcurrent, single cell overvoltage, single cell undervoltage, battery pack total voltage difference is too large, and remaining power is too low. Abnormal conditions of the battery pack

[0038] The present invention also receives the charging enable control signal of the inverter through the UPS system, receives battery parameter information, and real-time estimation data of the battery pack SOC and SOH, controls the battery detection module to close the slave relay to realize pre-charging of the battery pack; and when there is no battery pack fault in the battery pack and the charging start condition is met, closes the main relay to control the battery pack to enter the charging mode; and when the battery pack does not meet the charging start condition, controls the battery pack to enter the discharging mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0040] Figure 1 is a structural schematic diagram of a UPS system according to an embodiment of the present invention;

[0041] Figure 2 is a schematic structural diagram of a UPS system after a battery pack is installed according to an embodiment of the present invention;

[0042] Figure 3 is a flow chart of a SOC estimation method for a UPS system according to an embodiment of the present invention;

[0043] Figure 4 Schematic diagram of a SOH estimation method for a UPS system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0045] As attached Figure 1 and Figure 2 As shown, a UPS system includes a square box body 1, the left end and the right end of the bottom surface of the box body 1 extend upward to form the left side and the right side of the box body respectively, the rear side of the box body 1 is a U-shaped bracket 3, and the U-shaped bracket 3 is fixedly installed between the top surface and the bottom surface of the box body 1; the U-shaped bracket 3 is arranged in parallel to the rear side of the box body 1 and its U-shaped opening faces backward; a battery pack station 2 is arranged in the front middle part of the box body 1, and one or more battery packs are fixedly installed in the battery pack station 2; a cooling fan 5 is arranged on the right side of the box body 1, and a cooling hole 6 is arranged on the left side of the box body 1; a heat sink 18 is also arranged in the battery pack, and heat is transferred to the box body 1 through the heat sink.

[0046] The box 1 is also provided with an energy storage component, which includes UPS positive and negative bus bars 7, three battery packs 17, three battery detection modules, a battery management module 10 and a DC power supply module 11.

[0047] UPS positive and negative busbars 7, a main relay 12 is connected to the UPS positive busbar, and pre-charging relays 13 are also connected in parallel at both ends of the main relay 12. The main relay 12 and the pre-charging relay 13 are fixedly mounted on the right end between the upper and lower side walls of the U-shaped bracket 3. One end of the UPS positive and negative busbars is a charging and discharging port 14, which is arranged on the right side surface of the box.

[0048] Three battery packs 17 are fixedly mounted on the battery pack station 2. One or more battery groups connected in series in the battery pack have their negative poles connected to the main negative terminal of the battery pack, and their positive poles are connected in series with a fuse and then to the main positive terminal of the battery pack after a relay. The main positive and negative terminals of the battery pack are connected to the positive and negative busbars 7 of the UPS through the positive and negative busbars of the battery pack.

[0049] Three battery detection modules, which are arranged in the battery pack 17 and are provided with a voltage sampling terminal, a current sampling terminal and a CAN communication port. The battery detection module is connected in parallel to the positive and negative terminals of the battery pack through the voltage sampling terminal and is connected to the Hall sensor through the current sampling terminal, and is communicated with the battery management module 10 through the CAN communication port; the battery detection module is used to perform real-time battery performance detection on the battery pack, obtain battery parameter information, and perform real-time SOC estimation and SOH estimation on the battery according to the battery parameter information, and transmit the real-time SOC estimation data, SOH estimation data and real-time battery parameter information to the battery management module.

[0050] The battery management module 10 is arranged in the box body and fixedly mounted on the outer side of the bottom surface of the U-shaped bracket. A main relay control terminal and a pre-charge relay control terminal are arranged on it. The main relay control terminal is communicated with the main relay 12, and the pre-charge relay control terminal is communicated with the pre-charge relay 13. The battery management module 10 is also communicated with the inverter through the RS485 communication interface, and is connected to the battery detection module through the CAN communication interface; the battery management module 10 is used to perform pre-charge control and charge and discharge control on the battery pack according to the SOC real-time estimation data, SOH estimation data and real-time battery parameter information.

[0051] The DC power supply module 11 is fixedly mounted at the left end portion between the upper and lower side walls of the U-shaped bracket 3 and is electrically connected to the battery pack, the battery management module 10 and the battery detection module 9 respectively, so as to provide power for the battery management module 10 and the battery detection module 9.

[0052] In this embodiment, the UPS system receives the charging enable control signal of the inverter, receives battery parameter information and real-time estimation data of battery pack SOC and SOH through the battery management module, and controls the battery detection module to close the slave relay and pre-charge the battery pack; the UPS system also receives the charging and discharging enable control signal of the inverter through the battery management module, and when there is no battery pack fault in the battery pack and the charging start-up conditions are met, closes the main relay to control the battery pack to enter the charging mode; when the battery pack does not meet the charging start-up conditions, controls the battery pack to enter the discharging mode.

[0053] In this embodiment, a battery pack station is set in the front middle part of the box body, and the battery pack is fixedly installed on the battery pack station through a battery pack fixing base, and a battery group and a battery detection module are fixedly installed in the battery pack; at the same time, a U-shaped bracket is fixedly installed on the rear side surface of the box body, a DC power supply module, a main relay and a pre-charging relay are fixedly installed in the U-shaped bracket, and a battery management module is fixedly installed on the outer side of the bottom surface of the U-shaped bracket and located at the rear part of the box body, the positive and negative busbars of the UPS are respectively connected to the main relay and the pre-charging relay, and the charging and discharging ports thereof are installed on the right side surface of the box body of the UPS system, thereby realizing a reasonable layout of the UPS system.

[0054] This embodiment uses a cooling fan, cooling holes and heat sinks to achieve heat dissipation inside the UPS in a compact layout and small space in the box. The heat dissipation effect is good and can ensure the normal operation of various circuit devices in the UPS system.

[0055] As attached Figure 3 As shown, a method for estimating the remaining power of a battery pack of a UPS system comprises the following steps:

[0056] Step S101: The battery detection module detects and obtains battery parameter information of multiple single-cell lithium batteries in the battery pack, and estimates the battery SOH value. The battery parameter information includes the battery initial voltage V and the battery nominal capacity C.

[0057] Step S102: Based on the above battery performance data, the battery detection module estimates the initial battery capacity value E through the OCV-SOC curve soc_k-1 , and correct the initial capacity value of the battery in combination with the temperature correction factor and the battery SOH value, and correct the actual discharge capacity value C according to the temperature correction factor n_I (T,S,age).

[0058] Step S103: The battery detection module samples the sampling resistor through the differential isolation sampling circuit within the sampling period T and obtains the sampling current value i of the battery pack for integral calculation to obtain the charge change ΔQ of the battery pack. i , and its calculation formula is:

[0059] Step S104: The battery detection module determines the battery charging and discharging status and calculates the charge change ΔQ i Make corrections.

[0060] In this embodiment, the battery performance data includes the battery initial voltage V, the current sampling period t, the battery nominal capacity C, the battery SOH value, the ambient temperature T and the discharge current i. Among the battery performance parameters obtained, the battery initial voltage is V = 3.9v, the battery nominal capacity C = 100Ah, and the battery health status SOH = 100%; the battery initial capacity value is estimated by the OCV-SOC curve to be E soc_k-1 =76%, the actual discharge capacity of the battery is corrected by the temperature correction factor, that is, the actual discharge capacity value of the battery C n_I (T,S,age)=72.2Ah=259920As.

[0061] In this embodiment, since the charge and discharge state of the battery is a high current discharge state, in which the current is a high current, it is necessary to introduce the Peukert coefficient P=1.05 for current correction to calculate the charge change ΔQ i =i P t=193As, where the sampling current value i=150A, and the ambient temperature T=15℃.

[0062] In this embodiment, if the temperature correction factor, Peukert coefficient and other factors are not introduced, the charge change ΔQ at time k i =it=150As, the charge change error per unit time will be as high as 22%, and the full charge capacity of the battery is C n_I =100Ah=360000As, the error reaches 5%. The error of the SOC change value calculated by the two sets of error data will exceed 26%, which will greatly affect the accuracy of capacity estimation.

[0063] In this embodiment, the initial capacity value E of SOC is used. soc_k-1 =76%, the charge change after correction ΔQ i =193As and the actual discharge capacity of the battery C n_I (T, S, age) = 72.2Ah = 259920As, iteratively calculate and output the estimated SOC value at time k, the current SOC value of the battery is calculated by the formula

[0064] Preferably, step S104 is specifically:

[0065] Step S10401: The battery detection module determines the charge and discharge status of multiple lithium batteries in the battery pack.

[0066] Step S10402: If the battery detection module determines that the battery is in a high current discharge state, the charge change ΔQ is calculated using the Peukert coefficient. i Correction, the correction formula is ΔQ i =i P t, where i is the sampled current value, t is the ambient temperature of the battery pack, and P is the Peukert coefficient.

[0067] Step S10403: If the battery detection module determines that it is in the charging state, the charge change is corrected by the coulomb efficiency. The correction formula is ΔQ i =η(i,mode)ΔQ i ′, where i is the sampled current value, t is the ambient temperature of the battery pack, and η(i,mode) is the coulomb efficiency.

[0068] Step S105: Based on the SOC initial capacity value and the corrected charge change ΔQ i The battery detection module iteratively calculates and outputs the SOC estimation value at time k, where the SOC initial capacity value is the iteration variable, and the SOC estimation value at the previous time k-1 is used as the SOC initial capacity value at the next time k. The calculation formula of the SOC estimation value is: Among them, C n_I (T,S,age) is the nominal capacity of the nth battery.

[0069] Preferably, the initial capacity value E is estimated by the OCV-SOC curve. soc_k-1 Previously, it also included:

[0070] The battery detection module tests multiple single-cell lithium batteries through a battery testing system and obtains the charge and discharge curves of the multiple single-cell lithium batteries.

[0071] The battery detection module makes real-time corrections to the actual battery capacity when the battery is fully charged or empty.

[0072] According to the charge and discharge curve, the battery detection module continuously records the actual capacity value of the battery at each stage and each voltage platform, and uses the data fitting method to continuously correct the OCV-SOC curve through online self-learning.

[0073] As attached Figure 4 As shown, estimating and obtaining the battery SOH value includes the following steps:

[0074] Step S10101: The battery detection module obtains the real-time discharge amount during discharge, the discharge amount at the previous moment, the ambient temperature record value, and the number of discharges n, calculates the depth of discharge DOD and the average ambient temperature t, and further calculates the cycle life value A(x)*B(t) of the single cell.

[0075] Specifically, in this embodiment, the step includes:

[0076] The battery detection module detects and determines the charge and discharge status of the battery pack. In the discharge state, it records the battery data such as the discharge capacity, voltage, discharge times and battery ambient temperature of the single cell in real time.

[0077] The battery detection module obtains and records the power of the single cell. When the difference between the current power and the power recorded at the last moment is greater than 20%, the discharge depth DOD of the single cell begins to be calculated. The calculation method is: discharge depth DOD of the single cell = (the last recorded power - the current power) / rated capacity.

[0078] The average ambient temperature of the single cell is calculated based on the ambient temperatures of the single cell recorded multiple times during discharge.

[0079] Calculate the cycle life value A(x)*B(t) of the single cell, where x is the discharge depth DOD at the nth discharge, t is the average ambient temperature, A(x) is the cycle life, and B(t) is the life percentage; specifically, each time the number of discharges is counted, there will be a different discharge depth DOD, and the cycle life corresponding to different discharge depths DOD is different. In this embodiment, there is a linear relationship between the discharge depth DOD and the cycle life, that is, A(x)=5000-46x, etc.; and at different temperatures, the battery life will also change. In this embodiment, the ambient temperature and the life percentage are two linear relationships. When the temperature is less than 25°C, B(t)=(t+75) / 100, and when the temperature is greater than 25°C, B(t)=(160-2.4t) / 100; Through the above formula, the cycle life value A(x)*B(t) of the single cell can be calculated.

[0080] Step S10102: The battery detection module estimates the SOH of the single battery, and the estimation formula is:

[0081] The SOH of a single cell is estimated by the above method with high estimation accuracy and strong estimation stability.

[0082] In this embodiment, the battery detection module first detects and obtains battery parameter information and estimates and obtains the battery SOH value. Based on the above battery performance data, the battery detection module estimates the battery initial capacity value E soc_k-1 Then, the sampling resistor is sampled and the sampling current value i of the battery pack is obtained for integral calculation to obtain the charge change ΔQ of the battery pack. i ; Finally, according to the SOC initial capacity value and the corrected charge change ΔQ i, iteratively calculate and output the SOC estimation value at time k; through the above method, not only can the existing ampere-hour integration method and open-circuit voltage method be effectively combined to complete the estimation of the SOC value of the battery pack, effectively improving the SOC estimation accuracy and stability; but also realize the detection of various performance parameters of the battery in the UPS system, as well as the SOC estimation of the remaining power of the battery pack and the SOH estimation of the single cell, so as to achieve the purpose of monitoring the performance status of the battery pack, which is conducive to preventing the UPS system from having battery pack overcurrent, single cell overvoltage, single cell undervoltage, battery pack total voltage difference is too large, and the remaining power is too low. Abnormal conditions of the battery pack.

Claims

1. A method for estimating the remaining power of a battery pack of a UPS system, the method being applied to a UPS system, characterized in that: The UPS system comprises a box body, the left end and the right end of the bottom surface of the box body respectively extend upward to form the left side and the right side of the box body, the rear side of the box body is a U-shaped bracket, and the U-shaped bracket is fixedly installed between the top surface and the bottom surface of the box body; the U-shaped bracket is arranged in parallel to the rear side of the box body and its U-shaped opening faces backward; a battery pack station is arranged in the front middle part of the box body, and one or more battery packs are fixedly installed in the battery pack station; an energy storage component is also arranged in the box body, and the energy storage component includes: UPS positive and negative busbars, wherein the UPS positive and negative busbars are connected to a main relay, and both ends of the main relay are also connected in parallel to a pre-charging relay, and the main relay and the pre-charging relay are both fixedly mounted on the right end between the upper and lower side walls of the U-shaped bracket, and one end of the UPS positive and negative busbars is a charging and discharging port, which is arranged on the right side surface of the box body; One or more battery packs are fixedly mounted on the battery pack station. One or more battery groups connected in series are arranged in the battery pack, and their negative electrodes are connected to the main negative terminal of the battery pack. Their positive electrodes are connected in series with a fuse and then to the main positive terminal of the battery pack after a relay. The main positive and negative terminals of the battery pack are connected to the positive and negative busbars of the UPS through the positive and negative busbars of the battery pack. One or more battery detection modules, which are arranged in the battery pack and are provided with a voltage sampling terminal, a current sampling terminal and a CAN communication port. The battery detection module is connected in parallel to the positive and negative terminals of the battery pack through the voltage sampling terminal and is connected to the Hall sensor through the current sampling terminal, and is communicatively connected to the battery management module through the CAN communication port; the battery detection module is used to perform real-time battery performance detection on the battery pack, obtain battery parameter information, and perform real-time SOC estimation and SOH estimation on the battery according to the battery parameter information, and transmit the real-time SOC estimation data, SOH estimation data and real-time battery parameter information to the battery management module; A battery management module is arranged in the box and fixedly mounted at the bottom of the U-shaped bracket, on which a main relay control terminal and a pre-charge relay control terminal are arranged, the main relay control terminal is communicatively connected to the main relay, the pre-charge relay control terminal is communicatively connected to the pre-charge relay, the battery management module is also communicatively connected to the inverter via an RS485 communication interface, and is connected to the battery detection module via a CAN communication interface; the battery management module is used to perform pre-charge control and charge and discharge control on the battery pack according to SOC real-time estimation data, SOH estimation data and real-time battery parameter information; A DC power supply module is fixedly mounted on the left end portion between the upper and lower side walls of the U-shaped bracket, and is electrically connected to the battery pack, the battery management module, and the battery detection module, respectively, to provide power to the battery management module and the battery detection module; The method comprises the following steps: The battery detection module detects and obtains battery parameter information of multiple single-cell lithium batteries in the battery pack, and estimates and obtains the battery SOH value. The battery parameter information includes the battery initial voltage V and the battery nominal capacity C; Based on the above battery performance data, the battery detection module estimates the initial capacity value of the battery through the OCV-SOC curve The initial capacity value of the battery is corrected by combining the temperature correction factor and the battery SOH value, and the actual discharge capacity value C is corrected according to the temperature correction factor. n_I (T, S, age); The battery detection module samples the sampling resistor through the differential isolation sampling circuit within the sampling period T and obtains the sampling current value of the battery pack for integral calculation to obtain the charge change ΔQ of the battery pack. i , and its calculation formula is: The battery detection module determines the battery charging and discharging status and corrects the charge change; According to the SOC initial capacity value and the corrected charge change, the battery detection module iteratively calculates and outputs the SOC estimated value at the moment, wherein the SOC initial capacity value is an iterative variable, and the SOC estimated value at the previous moment k-1 is used as the SOC initial capacity value at the next moment k. The calculation formula of the SOC estimated value is: Among them, C n_I (T,S,age) is the nominal capacity of the nth battery.

2. The method for estimating the remaining power of a battery pack of a UPS system according to claim 1, characterized in that: The UPS system receives a charging enable control signal from the inverter, receives battery parameter information and real-time estimation data of battery pack SOC and SOH through a battery management module, controls a battery detection module to close a slave relay and pre-charges the battery pack.

3. The method for estimating the remaining power of a battery pack of a UPS system according to claim 2, characterized in that: The UPS system receives the charge and discharge enable control signal of the inverter through the battery management module. When there is no battery pack fault in the battery pack and the charging start condition is met, the main relay is closed to control the battery pack to enter the charging mode. When the battery pack does not meet the charging start condition, the battery pack is controlled to enter the discharging mode.

4. The method for estimating the remaining power of a battery pack of a UPS system according to claim 1, characterized in that: A battery pack fixing base is arranged on the battery pack station, a cooling fan is arranged on the right side surface of the box body, and a cooling hole is arranged on the left side of the box body.

5. The method for estimating the remaining power of a battery pack of a UPS system according to claim 1, characterized in that: The battery detection module determines the battery charging and discharging status and corrects the charge change, including: The battery detection module determines the charge and discharge status of multiple lithium-ion batteries in the battery pack; If the battery detection module determines that it is in a high current discharge state, the charge change is corrected by the Peukert coefficient. The correction formula is ΔQ i =i P t, where i is the sampling current value, t is the ambient temperature of the battery pack, and P is the Peukert coefficient; If the battery detection module determines that it is in a charging state, the charge change is corrected by the coulomb efficiency. The correction formula is ΔQ i =η(i,mode)ΔQ′ i , where i is the sampled current value, t is the ambient temperature of the battery pack, and η(i,mode) is the coulomb efficiency.

6. The method for estimating the remaining power of a battery pack of a UPS system according to claim 1, characterized in that: Estimate its initial capacity value through OCV-SOC curve Previously, it also included: The battery detection module tests multiple single-cell lithium batteries through a battery testing system and obtains the charge and discharge curves of the multiple single-cell lithium batteries; The battery detection module makes real-time corrections to the actual battery capacity when the battery is fully charged or empty. According to the charge and discharge curve, the battery detection module continuously records the actual capacity value of the battery at each stage and each voltage platform, and uses the data fitting method to continuously correct the OCV-SOC curve through online self-learning.

7. The method for estimating the remaining power of a battery pack of a UPS system according to claim 1, characterized in that: Estimating and obtaining the battery SOH value includes the following steps: The battery detection module obtains the real-time discharge amount during discharge, the discharge amount at the last moment, the ambient temperature record value, and the number of discharges n, calculates the depth of discharge DOD and the average ambient temperature t, and further calculates the cycle life value A(x)*B(t) of the single cell; The battery detection module estimates the SOH of the single battery, and the estimation formula is:

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