A method and system for online DCR testing of energy storage batteries

Abstract

This invention provides a method and system for online DCR detection of energy storage batteries in the field of battery online testing technology. The method includes the following steps: Step S10: Setting a State of Charge (SOC) 1, a State of Charge (SOC) 2, and a peak-shaving and valley-filling strategy, wherein SOC 1 is greater than SOC 2; During operation of the electrochemical energy storage system, the energy storage battery is charged to SOC 1 based on the peak-shaving and valley-filling strategy; Step S20: The electrochemical energy storage system controls the energy storage battery to discharge to SOC 2 based on the peak-shaving and valley-filling strategy, and performs online discharge DCR detection during the discharge process; Step S30: The electrochemical energy storage system controls the energy storage battery to charge from SOC 2 to SOC 1 based on the peak-shaving and valley-filling strategy, and performs online charging DCR detection during the charging process. After the online charging DCR detection is completed, the online discharge DCR detection is performed cyclically. The advantage of this invention is that it enables online DCR detection of energy storage batteries, greatly improving the safety of energy storage battery use.

Description

Technical Field

[0001] This invention relates to the field of online battery testing technology, and in particular to an online DCR testing method and system for energy storage batteries. Background Technology

[0002] An electrochemical energy storage system (EESS) is a system that uses electrochemical batteries as the energy storage medium and cyclically stores and releases electrical energy through an energy storage converter. A key function of EESS is peak shaving and valley filling, which involves charging the storage batteries from the grid during off-peak hours to store energy, and releasing the stored energy during peak hours. Peak shaving and valley filling help the grid reduce peak load and increase off-peak load, smoothing the load curve, improving load factor, and reducing electricity demand. Furthermore, because electricity prices are high during peak hours and low during off-peak hours, peak arbitrage can be achieved through EESS, improving economic efficiency.

[0003] One important indicator for energy storage batteries is their direct current resistance (DCR), which refers to the resistance encountered when direct current flows through the battery during operation. DCR plays a crucial role in assessing battery aging and charge / discharge capabilities because excessive DCR poses the following risks: 1. As DCR increases, battery capacity continuously decreases; 2. Since U = I × R, under the same charge / discharge rate conditions, increased DCR leads to a greater voltage drop caused by the battery's internal resistance, easily resulting in overcharging or over-discharging, which can cause irreversible damage to the energy storage battery; 3. Since P = I... 2 According to ×R, under the same charge and discharge rate conditions, an increase in DCR will lead to an increase in heat generation, which will further increase the risk of thermal runaway of the energy storage battery.

[0004] Therefore, considering the performance and safety of energy storage batteries, it is essential to conduct DCR testing during use. However, traditionally, DCR testing is only performed before energy storage batteries leave the factory. After being installed in an electrochemical energy storage system, the system needs to operate for extended periods, making periodic disassembly and testing unsuitable. Furthermore, limitations in the working environment, equipment accuracy, and operating conditions lead to large DCR measurement errors in the energy storage battery, making it difficult to implement online DCR testing within the electrochemical energy storage system.

[0005] Therefore, how to provide an online DCR detection method and system for energy storage batteries to improve the safety of energy storage battery use has become an urgent technical problem to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method and system for online DCR detection of energy storage batteries, so as to improve the safety of energy storage battery use.

[0007] In a first aspect, the present invention provides an online detection method for the DCR of an energy storage battery, comprising the following steps:

[0008] Step S10: Set a SOC1, a SOC2 and a peak shaving and valley filling strategy, wherein SOC1 is greater than SOC2; when the electrochemical energy storage system is running, the energy storage battery is charged to SOC1 based on the peak shaving and valley filling strategy.

[0009] Step S20: The electrochemical energy storage system controls the energy storage battery to discharge to SOC2 based on the peak shaving and valley filling strategy, and performs online discharge DCR detection during the discharge process;

[0010] Step S30: Based on the peak shaving and valley filling strategy, the electrochemical energy storage system controls the energy storage battery to charge from SOC2 to SOC1. During the charging process, online charging DCR detection is performed. After the online charging DCR detection is completed, online discharging DCR detection is performed cyclically.

[0011] Furthermore, in step S10, the value of SOC1 is 90% to 95%; and the value of SOC2 is 5% to 10%.

[0012] Further, in step S20, the online detection of discharge DCR specifically includes:

[0013] Step S21: Divide the charging current into n levels according to the charging rate: B = [I B1 I B2 , ..., I Bn ];

[0014] Step S22: Control the target temperature of the energy storage battery within the range of T3 to T4, and control the energy storage battery to remain stationary for more than t3 time based on the preset scheduling management strategy.

[0015] Step S23: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 3x and current value i 3x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0016] Step S24: The monitoring module obtains the discharge demand current value based on the scheduling management strategy, and matches the current that is greater than and closest to the discharge demand current value from B as the discharge current value I. B Based on the I B Control the constant current discharge duration t4 of the energy storage battery;

[0017] Step S25: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 4x and current value i 4x ;

[0018] Step S26, based on the u 3x u 4x 、i 3x and i 4x Calculate the discharge DCR of each energy storage battery cluster:

[0019] DCR 放x =(u 4x -u 3x ) / (i 4x -i 3x ).

[0020] Further, in step S21, the value of n is 5, I B1 I B2 I B3 I B4 I B5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively.

[0021] In step S22, T3 is 10℃ and T4 is 30℃;

[0022] The values ​​of t3 and t4 are between 10s and 20s.

[0023] Further, in step S30, the online charging DCR detection specifically includes:

[0024] Step S31: Divide the charging current into m levels according to the charging rate: A = [I A1 I A2 , ..., I Am ];

[0025] Step S32: Control the target temperature of the energy storage battery within the range of T1 to T2, and control the energy storage battery to remain stationary for more than t1 time based on the preset scheduling management strategy.

[0026] Step S33: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 1x and current value i 1x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0027] Step S34: The monitoring module obtains the charging demand current value based on the scheduling management strategy, and matches the current value that is less than and closest to the charging demand current value from A as the charging current value I. A Based on the IA Control the constant current charging time t2 of the energy storage battery;

[0028] Step S35: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 2x and current value i 2x ;

[0029] Step S36, based on the u 1x u 2x 、i 1x and i 2x Calculate the charge DCR of each energy storage cell cluster:

[0030] DCR 充x =(u 2x -u 1x ) / (i 2x -i 1x );

[0031] In step S31, the value of m is 5, I A1 I A2 I A3 I A4 I A5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively.

[0032] In step S32, T1 is 10℃ and T2 is 30℃;

[0033] The values ​​of t1 and t2 are between 10s and 20s.

[0034] Secondly, the present invention provides an online DCR detection system for energy storage batteries, comprising the following modules:

[0035] An initial charging module is used to set a SOC1, a SOC2, and a peak shaving and valley filling strategy, wherein SOC1 is greater than SOC2; when the electrochemical energy storage system is running, the energy storage battery is charged to SOC1 based on the peak shaving and valley filling strategy.

[0036] The discharge DCR online detection module is used in the electrochemical energy storage system to control the energy storage battery to discharge to SOC2 based on the peak shaving and valley filling strategy, and to perform online discharge DCR detection during the discharge process.

[0037] The online charging DCR detection module is used in the electrochemical energy storage system to control the energy storage battery to charge from SOC2 to SOC1 based on the peak shaving and valley filling strategy. During the charging process, the online charging DCR is detected, and after the online charging DCR is completed, the online discharging DCR is detected in a cycle.

[0038] Furthermore, in the initial charging module, the SOC1 value is 90% to 95%; and the SOC2 value is 5% to 10%.

[0039] Furthermore, in the discharge DCR online detection module, the discharge DCR online detection specifically includes:

[0040] The charging current grading unit is used to divide the charging current into n grades according to the charging rate: B = [I B1 I B2 , ..., I Bn ];

[0041] The first temperature control and resting unit is used to control the target temperature of the energy storage battery in the range of T3 to T4, and to control the energy storage battery to rest for more than t3 time based on the preset scheduling and management strategy.

[0042] The first data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 3x and current value i 3x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0043] The discharge unit is used by the monitoring module to obtain the discharge demand current value based on the scheduling management strategy, and to match the current value that is greater than and closest to the discharge demand current value from B as the discharge current value I. B Based on the I B Control the constant current discharge duration t4 of the energy storage battery;

[0044] The second data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 4x and current value i 4x ;

[0045] Discharge DCR calculation unit, used for calculating based on the u 3x u 4x 、i 3x and i 4x Calculate the discharge DCR of each energy storage battery cluster:

[0046] DCR 放x =(u 4x -u 3x ) / (i 4x -i 3x ).

[0047] Furthermore, in the charging current grading unit, the value of n is 5, I B1 I B2 I B3 I B4 I B5The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively.

[0048] In the first temperature-controlled static unit, T3 is 10℃ and T4 is 30℃;

[0049] The values ​​of t3 and t4 are between 10s and 20s.

[0050] Furthermore, in the online charging DCR detection module, the online charging DCR detection specifically includes:

[0051] The discharge current grading unit is used to divide the charging current into m grades according to the charging rate: A = [I A1 I A2 , ..., I Am ];

[0052] The second temperature control and resting unit is used to control the target temperature of the energy storage battery within the range of T1 to T2, and to control the energy storage battery to rest for more than t1 time based on the preset scheduling and management strategy.

[0053] The third data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 1x and current value i 1x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0054] The charging unit is used to monitor the module to obtain the charging demand current value based on the scheduling management strategy, and to match the current value that is less than and closest to the charging demand current value from A as the charging current value I. A Based on the I A Control the constant current charging time t2 of the energy storage battery;

[0055] The fourth data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 2x and current value i 2x ;

[0056] The charging DCR calculation unit is used to calculate the value based on the u. 1x u 2x 、i 1x and i 2x Calculate the charge DCR of each energy storage cell cluster:

[0057] DCR 充x =(u 2x -u 1x ) / (i 2x -i 1x );

[0058] In the discharge current grading unit, the value of m is 5, I A1 I A2 I A3 I A4 I A5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively.

[0059] In the second temperature-controlled static unit, T1 is 10℃ and T2 is 30℃;

[0060] The values ​​of t1 and t2 are between 10s and 20s.

[0061] The advantages of the present invention are:

[0062] 1. By setting SOC1, SOC2, and peak shaving and valley filling strategies, the energy storage battery is controlled for charging and discharging. During the charging and discharging process, the charging DCR and discharging DCR of the energy storage battery are monitored online. Before DCR detection, the charging and discharging current is divided into levels, the target temperature of the energy storage battery is controlled, and the battery is left to stand for a preset time. The first voltage and current values ​​are collected. Then, based on the charging and discharging current requirements, the corresponding charging and discharging current value is matched from the divided current to control the energy storage battery for the preset charging and discharging time. The second voltage and current values ​​are collected. The DCR is calculated based on the two sets of voltage and current data. This realizes online DCR detection of the energy storage battery, reduces damage caused by overcharging and over-discharging, avoids thermal runaway of the energy storage battery, and thus greatly improves the safety of energy storage battery use.

[0063] 2. By dividing the charging and discharging current into different ranges, the consistency of the test current is ensured; by controlling the charging and discharging of the energy storage battery through the set SOC1 and SOC2, the consistency of SOC during DCR testing is ensured, and overcharging and over-discharging of the energy storage battery are avoided; combined with temperature control and resting time control of the energy storage battery, the accuracy of online DCR testing of the energy storage battery is greatly improved. Attached Figure Description

[0064] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0065] Figure 1 This is a flowchart of an online DCR detection method for energy storage batteries according to the present invention.

[0066] Figure 2 This is a schematic diagram of the structure of an online DCR detection system for energy storage batteries according to the present invention.

[0067] Figure 3 This is a hardware architecture diagram of the electrochemical energy storage system of the present invention. Detailed Implementation

[0068] Please refer to Figures 1 to 3 As shown, the present invention requires the use of an electrochemical energy storage system, comprising a monitoring module, an energy storage converter, an energy storage battery, a temperature control module, and several voltage and current acquisition modules; the monitoring module is communicatively connected to the energy storage converter, the energy storage battery, the temperature control module, and the voltage and current acquisition modules; the energy storage converter is communicatively connected to the energy storage battery; the voltage and current acquisition modules are used to acquire the total voltage and current of each cluster of the energy storage battery; the temperature control module controls the temperature of the energy storage battery; the energy storage converter is connected to AC equipment, such as transformers, switches, and photovoltaic inverters, via an AC bus, and to DC equipment, such as DC charging piles, via a DC bus.

[0069] When the DCR measurement accuracy requirement is not high (e.g., >50%), the voltage and current acquisition module can be replaced by the voltage and current acquisition circuit built into the energy storage battery, which obtains the voltage and current values ​​of the energy storage battery through communication; while when the measurement accuracy requirement is high, an external voltage and current acquisition module is used.

[0070] The communication between the voltage and current acquisition module and the monitoring module can be achieved via RS485, CAN, or Ethernet.

[0071] To improve the accuracy of DCR measurement, the external voltage and current acquisition module is selected with an error ≤ ±0.1%FS.

[0072] A preferred embodiment of the online DCR detection method for energy storage batteries according to the present invention includes the following steps:

[0073] Step S10: Set a SOC1, a SOC2, and a peak shaving and valley filling strategy, wherein SOC1 is greater than SOC2; when the electrochemical energy storage system is running, the energy storage battery is charged to SOC1 based on the peak shaving and valley filling strategy; the energy storage battery is charged and discharged by setting the SOC1 and SOC2, which not only retains a certain margin to avoid overcharging or over-discharging, but also achieves a large charging and discharging range.

[0074] Step S20: The electrochemical energy storage system controls the energy storage battery to discharge to SOC2 based on the peak shaving and valley filling strategy, and performs online discharge DCR detection during the discharge process;

[0075] Step S30: Based on the peak shaving and valley filling strategy, the electrochemical energy storage system controls the energy storage battery to charge from SOC2 to SOC1. During the charging process, online charging DCR detection is performed. After the online charging DCR detection is completed, online discharging DCR detection is performed cyclically.

[0076] In step S10, the value of SOC1 is 90% to 95%; the value of SOC2 is 5% to 10%.

[0077] In step S20, the online detection of discharge DCR specifically includes:

[0078] Step S21: Divide the charging current into n levels according to the charging rate: B = [I B1 I B2 , ..., I Bn ];

[0079] Step S22: Control the target temperature of the energy storage battery within the range of T3 to T4, and control the energy storage battery to rest for more than t3 time based on the preset scheduling management strategy to improve the consistency of the detection conditions; the charging current is divided into non-linear levels and sorted according to the order of magnitude.

[0080] Step S23: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 3x and current value i 3x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0081] Step S24: The monitoring module obtains the discharge demand current value based on the scheduling management strategy, and matches the current that is greater than and closest to the discharge demand current value from B as the discharge current value I. B Based on the I B Control the constant current discharge duration t4 of the energy storage battery;

[0082] Step S25: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 4x and current value i 4x ;

[0083] Step S26, based on the u 3x u 4x 、i 3x and i 4x Calculate the discharge DCR of each energy storage battery cluster:

[0084] DCR 放x =(u 4x -u 3x ) / (i 4x -i 3x ).

[0085] In step S21, the value of n is 5, I B1 I B2 I B3 I B4 I B5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively; C represents the charging rate.

[0086] In step S22, T3 is 10℃ and T4 is 30℃;

[0087] The values ​​of t3 and t4 are between 10s and 20s.

[0088] In step S30, the online charging DCR detection specifically includes:

[0089] Step S31: Divide the charging current into m levels according to the charging rate: A = [I A1 I A2 , ..., I Am ];

[0090] Step S32: Control the target temperature of the energy storage battery within the range of T1 to T2, and control the energy storage battery to remain stationary for more than t1 time based on the preset scheduling management strategy.

[0091] Step S33: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 1x and current value i 1x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0092] Step S34: The monitoring module obtains the charging demand current value based on the scheduling management strategy, and matches the current value that is less than and closest to the charging demand current value from A as the charging current value I. A Based on the I A Control the constant current charging time t2 of the energy storage battery;

[0093] Step S35: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 2x and current value i 2x ;

[0094] Step S36, based on the u 1x u 2x 、i 1x and i 2x Calculate the charge DCR of each energy storage cell cluster:

[0095] DCR 充x =(u 2x -u 1x ) / (i 2x -i 1x );

[0096] In step S31, the value of m is 5, I A1 I A2 I A3 I A4 I A5The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively.

[0097] In step S32, T1 is 10℃ and T2 is 30℃;

[0098] The values ​​of t1 and t2 are between 10s and 20s.

[0099] Also includes:

[0100] Step S40, according to the I A and I B For DCR 充x and DCR 放x The DCR values ​​are classified to obtain a sequence of DCR values ​​at the corresponding charge / discharge rates. Based on the DCR value sequence, m charging DCR change curves and n discharging DCR change curves are obtained.

[0101] The DCR growth rate is calculated based on the charging DCR change curve and the discharging DCR change curve.

[0102] The DCR growth rate and DCR value are compared with those of similar energy storage batteries to verify whether the DCR of the energy storage battery is abnormal.

[0103] A preferred embodiment of the energy storage battery DCR online detection system of the present invention includes the following modules:

[0104] The initial charging module is used to set a SOC1, a SOC2 and a peak shaving and valley filling strategy, wherein SOC1 is greater than SOC2; when the electrochemical energy storage system is running, the energy storage battery is charged to SOC1 based on the peak shaving and valley filling strategy; the energy storage battery is charged and discharged by setting SOC1 and SOC2, which not only retains a certain margin to avoid overcharging or over-discharging, but also achieves a large charging and discharging range.

[0105] The discharge DCR online detection module is used in the electrochemical energy storage system to control the energy storage battery to discharge to SOC2 based on the peak shaving and valley filling strategy, and to perform online discharge DCR detection during the discharge process.

[0106] The online charging DCR detection module is used in the electrochemical energy storage system to control the energy storage battery to charge from SOC2 to SOC1 based on the peak shaving and valley filling strategy. During the charging process, the online charging DCR is detected, and after the online charging DCR is completed, the online discharging DCR is detected in a cycle.

[0107] In the initial charging module, the SOC1 value is 90% to 95%; the SOC2 value is 5% to 10%.

[0108] In the discharge DCR online detection module, the discharge DCR online detection specifically includes:

[0109] The charging current grading unit is used to divide the charging current into n grades according to the charging rate: B = [I B1 I B2 , ..., I Bn ];

[0110] The first temperature control and resting unit is used to control the target temperature of the energy storage battery within the range of T3 to T4, and to control the energy storage battery to rest for more than t3 time based on a preset scheduling and management strategy, so as to improve the consistency of detection conditions; the charging current is divided into non-linear levels and sorted according to the order of magnitude.

[0111] The first data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 3x and current value i 3x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0112] The discharge unit is used by the monitoring module to obtain the discharge demand current value based on the scheduling management strategy, and to match the current value that is greater than and closest to the discharge demand current value from B as the discharge current value I. B Based on the I B Control the constant current discharge duration t4 of the energy storage battery;

[0113] The second data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 4x and current value i 4x ;

[0114] Discharge DCR calculation unit, used for calculating based on the u 3x u 4x 、i 3x and i 4x Calculate the discharge DCR of each energy storage battery cluster:

[0115] DCR 放x =(u 4x -u 3x ) / (i 4x -i 3x ).

[0116] In the charging current grading unit, the value of n is 5, I B1 I B2 I B3 I B4 I B5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively; C represents the charging rate.

[0117] In the first temperature-controlled static unit, T3 is 10℃ and T4 is 30℃;

[0118] The values ​​of t3 and t4 are between 10s and 20s.

[0119] In the charging DCR online detection module, the charging DCR online detection specifically includes:

[0120] The discharge current grading unit is used to divide the charging current into m grades according to the charging rate: A = [I A1 I A2 , ..., I Am ];

[0121] The second temperature control and resting unit is used to control the target temperature of the energy storage battery within the range of T1 to T2, and to control the energy storage battery to rest for more than t1 time based on the preset scheduling and management strategy.

[0122] The third data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 1x and current value i 1x , and x∈[1,c], where c is the total number of energy storage battery clusters;

[0123] The charging unit is used to monitor the module to obtain the charging demand current value based on the scheduling management strategy, and to match the current value that is less than and closest to the charging demand current value from A as the charging current value I. A Based on the I A Control the constant current charging time t2 of the energy storage battery;

[0124] The fourth data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 2x and current value i 2x ;

[0125] The charging DCR calculation unit is used to calculate the value based on the u. 1x u 2x 、i 1x and i 2x Calculate the charge DCR of each energy storage cell cluster:

[0126] DCR 充x =(u 2x -u 1x ) / (i 2x -i 1x );

[0127] In the discharge current grading unit, the value of m is 5, I A1 I A2 IA3 I A4 I A5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively.

[0128] In the second temperature-controlled static unit, T1 is 10℃ and T2 is 30℃;

[0129] The values ​​of t1 and t2 are between 10s and 20s.

[0130] Also includes:

[0131] The DCR analysis module is used to analyze the data based on the I... A and I B For DCR 充x and DCR 放x The DCR values ​​are classified to obtain a sequence of DCR values ​​at the corresponding charge / discharge rates. Based on the DCR value sequence, m charging DCR change curves and n discharging DCR change curves are obtained.

[0132] The DCR growth rate is calculated based on the charging DCR change curve and the discharging DCR change curve.

[0133] The DCR growth rate and DCR value are compared with those of similar energy storage batteries to verify whether the DCR of the energy storage battery is abnormal.

[0134] In summary, the advantages of this invention are:

[0135] 1. By setting SOC1, SOC2, and peak shaving and valley filling strategies, the energy storage battery is controlled for charging and discharging. During the charging and discharging process, the charging DCR and discharging DCR of the energy storage battery are monitored online. Before DCR detection, the charging and discharging current is divided into levels, the target temperature of the energy storage battery is controlled, and the battery is left to stand for a preset time. The first voltage and current values ​​are collected. Then, based on the charging and discharging current requirements, the corresponding charging and discharging current value is matched from the divided current to control the energy storage battery for the preset charging and discharging time. The second voltage and current values ​​are collected. The DCR is calculated based on the two sets of voltage and current data. This realizes online DCR detection of the energy storage battery, reduces damage caused by overcharging and over-discharging, avoids thermal runaway of the energy storage battery, and thus greatly improves the safety of energy storage battery use.

[0136] 2. By dividing the charging and discharging current into different ranges, the consistency of the test current is ensured; by controlling the charging and discharging of the energy storage battery through the set SOC1 and SOC2, the consistency of SOC during DCR testing is ensured, and overcharging and over-discharging of the energy storage battery are avoided; combined with temperature control and resting time control of the energy storage battery, the accuracy of online DCR testing of the energy storage battery is greatly improved.

[0137] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for online detection of DCR in energy storage batteries, characterized in that: Includes the following steps: Step S10: Set a SOC1, a SOC2 and a peak shaving and valley filling strategy, wherein SOC1 is greater than SOC2; when the electrochemical energy storage system is running, the energy storage battery is charged to SOC1 based on the peak shaving and valley filling strategy. Step S20: The electrochemical energy storage system controls the energy storage battery to discharge to SOC2 based on the peak shaving and valley filling strategy, and performs online discharge DCR detection during the discharge process; Step S30: Based on the peak shaving and valley filling strategy, the electrochemical energy storage system controls the energy storage battery to charge from SOC2 to SOC1. During the charging process, online charging DCR detection is performed. After the online charging DCR detection is completed, online discharging DCR detection is performed cyclically. In step S20, the online detection of discharge DCR specifically includes: Step S21: Divide the charging current into n levels according to the charging rate: B = [I B1 I B2 , ..., I Bn The value of n is 5, I B1 I B2 I B3 I B4 I B5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively. Step S22: Control the target temperature of the energy storage battery within the range of T3~T4, and control the energy storage battery to remain stationary for more than t3 time based on the preset scheduling management strategy; T3 is 10℃, T4 is 30℃; the values ​​of t3 and t4 are 10s~20s. Step S23: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 3x and current value i 3x , and x∈[1,c], where c is the total number of energy storage battery clusters; Step S24: The monitoring module obtains the discharge demand current value based on the scheduling management strategy, matches the value greater than the discharge demand current value from B, and uses the closest current as the discharge current value I. B Based on the I B Control the constant current discharge duration t4 of the energy storage battery; Step S25: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 4x and current value i 4x ; Step S26, based on the u 3x u 4x i 3x and i 4x Calculate the discharge DCR of each energy storage battery cluster: DCR 放x =(in 4x -in 3x ) / (and 4x -and 3x ().

2. The online DCR detection method for energy storage batteries as described in claim 1, characterized in that: In step S10, the value of SOC1 is 90%~95%; the value of SOC2 is 5%~10%.

3. The online DCR detection method for energy storage batteries as described in claim 1, characterized in that: In step S30, the online charging DCR detection specifically includes: Step S31: Divide the charging current into m levels according to the charging rate: A = [I A1 I A2 , ..., I Am ]; Step S32: Control the target temperature of the energy storage battery within the range of T1~T2, and control the energy storage battery to remain stationary for more than t1 time based on the preset scheduling management strategy. Step S33: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 1x and current value i 1x , and x∈[1,c], where c is the total number of energy storage battery clusters; Step S34: The monitoring module obtains the charging demand current value based on the scheduling management strategy, and matches the current value that is less than and closest to the charging demand current value from A as the charging current value I. A Based on the I A Control the constant current charging time t2 of the energy storage battery; Step S35: The monitoring module acquires the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 2x and current value i 2x ; Step S36, based on the u 1x u 2x i 1x and i 2x Calculate the charge DCR of each energy storage cell cluster: DCR 充x =(in 2x -in 1x ) / (and 2x -and 1x ); In step S31, the value of m is 5, I A1 I A2 I A3 I A4 I A5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively. In step S32, T1 is 10℃ and T2 is 30℃; The values ​​of t1 and t2 are 10s to 20s.

4. An online DCR testing system for energy storage batteries, characterized in that: Includes the following modules: An initial charging module is used to set a SOC1, a SOC2, and a peak shaving and valley filling strategy, wherein SOC1 is greater than SOC2; when the electrochemical energy storage system is running, the energy storage battery is charged to SOC1 based on the peak shaving and valley filling strategy. The discharge DCR online detection module is used in the electrochemical energy storage system to control the energy storage battery to discharge to SOC2 based on the peak shaving and valley filling strategy, and to perform online discharge DCR detection during the discharge process. The charging DCR online detection module is used in the electrochemical energy storage system to control the energy storage battery to charge from SOC2 to SOC1 based on the peak shaving and valley filling strategy. During the charging process, the charging DCR online detection is performed, and after the charging DCR online detection is completed, the discharging DCR online detection is performed cyclically. In the discharge DCR online detection module, the discharge DCR online detection specifically includes: The charging current grading unit is used to divide the charging current into n grades according to the charging rate: B=[I B1 I B2 , ..., I Bn The value of n is 5, I B1 I B2 I B3 I B4 I B5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively. The first temperature control and resting unit is used to control the target temperature of the energy storage battery within the range of T3 to T4, and to control the energy storage battery to rest for more than t3 time based on a preset scheduling and management strategy; T3 is 10℃ and T4 is 30℃; the values ​​of t3 and t4 are 10s to 20s. The first data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 3x and current value i 3x , and x∈[1,c], where c is the total number of energy storage battery clusters; The discharge unit is used by the monitoring module to obtain the discharge demand current value based on the scheduling management strategy, and to match the current value greater than the discharge demand current value from B and use the closest current value as the discharge current value I. B Based on the I B Control the constant current discharge duration t4 of the energy storage battery; The second data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 4x and current value i 4x ; Discharge DCR calculation unit, used for calculating based on the u 3x u 4x i 3x and i 4x Calculate the discharge DCR of each energy storage battery cluster: DCR 放x =(in 4x -in 3x ) / (and 4x -and 3x ().

5. The energy storage battery DCR online detection system as described in claim 4, characterized in that: In the initial charging module, the SOC1 value is 90%~95%; the SOC2 value is 5%~10%.

6. The energy storage battery DCR online detection system as described in claim 4, characterized in that: In the charging DCR online detection module, the charging DCR online detection specifically includes: The discharge current grading unit is used to divide the charging current into m grades according to the charging rate: A=[I A1 I A2 , ..., I Am ]; The second temperature control and resting unit is used to control the target temperature of the energy storage battery within the range of T1~T2, and to control the energy storage battery to rest for more than t1 time based on the preset scheduling and management strategy. The third data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 1x and current value i 1x , and x∈[1,c], where c is the total number of energy storage battery clusters; The charging unit is used to monitor the module to obtain the charging demand current value based on the scheduling management strategy, and to match the current value that is less than and closest to the charging demand current value from A as the charging current value I. A Based on the I A Control the constant current charging time t2 of the energy storage battery; The fourth data acquisition unit is used by the monitoring module to acquire the voltage value u of each energy storage battery cluster through the voltage and current acquisition module. 2x and current value i 2x ; The charging DCR calculation unit is used to calculate the value based on the u. 1x u 2x i 1x and i 2x Calculate the charge DCR of each energy storage cell cluster: DCR 充x =(in 2x -in 1x ) / (and 2x -and 1x ); In the discharge current grading unit, the value of m is 5, I A1 I A2 I A3 I A4 I A5 The values ​​are 0.1C, 0.2C, 0.3C, 0.5C, and 0.8C, respectively. In the second temperature-controlled static unit, T1 is 10℃ and T2 is 30℃; The values ​​of t1 and t2 are 10s to 20s.

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