A lead-acid battery pack equalization management device

Abstract

The application provides a lead-acid storage battery pack equalization management device and relates to the technical field of storage battery management.The voltage acquisition module, the internal resistance measurement module and the temperature acquisition module send the voltage, the internal resistance and the temperature of each single storage battery to the monitoring module in the same inspection cycle, and the current acquisition module sends the equalization loop current to the monitoring module during the supplement charging or discharging; the monitoring module forms the voltage reference value and the voltage deviation according to the voltage of each single storage battery, forms the internal resistance reference value and the internal resistance deviation according to the internal resistance of each single storage battery, and determines the single storage battery needing maintenance, the equalization direction, the equalization current and the equalization period; the switching circuit makes the equalization charging module or the equalization discharging module access to the two ends of the single storage battery needing maintenance according to the series position of the single storage battery needing maintenance and executes the supplement charging or discharging.The application is favorable for controlling the expansion of the single difference of the series storage battery pack, reducing the overcharging and overdischarging risk and improving the available capacity.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a lead-acid battery pack equalization management device. Background Technology

[0002] Lead-acid battery packs are widely used in backup power systems. A lead-acid battery pack typically consists of multiple individual batteries connected in series. During long-term float charging, charge-discharge cycles, and changes in ambient temperature, the individual batteries will exhibit different operating states due to capacity decay, differences in self-discharge, and changes in internal resistance. If any individual battery in the series structure reaches its upper charge limit or lower discharge limit prematurely, it will affect the charge-discharge control of the entire battery pack, thus limiting the usable capacity and lifespan of the battery pack.

[0003] Existing battery management equipment mostly uses the overall voltage or current of the battery pack as the control basis, mainly for overall charging, discharging, or alarm protection of the battery pack. It is difficult to identify the state deviation between individual batteries during online operation, and it is also difficult to perform independent supplementary charging or discharging maintenance on specific individual batteries. Although some equipment can collect individual battery voltage, it lacks linkage verification for changes in internal resistance, temperature status, and equalization execution current, which can easily lead to inaccurate selection of equalization targets, thermal runaway during the equalization process, or abnormal switching connections.

[0004] Therefore, a balanced management scheme is needed that can acquire the operating status of individual cells online, determine the cells that need maintenance, control the cells to be recharged or discharged, and verify the execution process, so as to reduce the risk of overcharging and over-discharging caused by the expansion of differences between individual cells during the operation of series battery packs. Summary of the Invention

[0005] To address the problem that existing battery management devices primarily rely on overall group parameters for charge and discharge control, making it difficult to perform online identification, independent connection, and safe equalization maintenance of individual batteries in a series-connected battery pack, this invention provides a lead-acid battery pack equalization management device.

[0006] This invention provides a lead-acid battery pack balancing management device, comprising a voltage acquisition module, a current acquisition module, an internal resistance measurement module, a temperature acquisition module, a monitoring module, a balancing charging module, a balancing discharging module, and a switching circuit. The voltage acquisition module, internal resistance measurement module, and temperature acquisition module send the voltage, internal resistance, and temperature of each individual battery cell to the monitoring module within the same inspection cycle. The current acquisition module sends the balancing circuit current to the monitoring module during supplementary charging or discharging. The monitoring module forms a voltage reference value based on the voltage of each individual battery cell within the same inspection cycle, and forms a voltage deviation based on the deviation of the individual battery cell voltage from the voltage reference value. The monitoring module also forms an internal resistance reference value based on the internal resistance of each individual battery cell within the same inspection cycle, and forms an internal resistance deviation based on the deviation of the individual battery cell internal resistance from the internal resistance reference value. The monitoring module determines the individual battery cell requiring maintenance and the balancing direction based on the voltage deviation, determines the balancing current and balancing period based on the internal resistance deviation and the individual battery cell temperature, and verifies the execution current for supplementary charging or discharging based on the balancing circuit current. The switching circuit connects the equalization charging module or equalization discharging module to the two ends of the individual battery to be maintained according to the series connection position of the individual battery to be maintained, and performs supplementary charging or discharging.

[0007] Furthermore, when the monitoring module generates voltage deviation and internal resistance deviation, it records the individual battery voltage and internal resistance within the same inspection cycle according to the series serial number of the individual batteries. The arithmetic mean of the voltage of each individual battery is used as the voltage reference value, and the arithmetic mean of the internal resistance of each individual battery is used as the internal resistance reference value. The difference between the individual battery voltage and the voltage reference value is used to generate the voltage deviation, and the difference between the individual battery internal resistance and the internal resistance reference value is used to generate the internal resistance deviation.

[0008] Furthermore, when the voltage deviation is negative, the monitoring module identifies the corresponding single battery cell as a target for supplemental charging; when the voltage deviation is positive, the monitoring module identifies the corresponding single battery cell as a target for discharge. The monitoring module treats the target cells for supplemental charging and the target cells for discharge as single batteries requiring maintenance, and determines the balancing direction according to the target cells for supplemental charging or discharge.

[0009] Furthermore, when the monitoring module determines that the object to be recharged has a positive deviation in internal resistance, it configures the balancing period to include at least two recharge periods, as well as an internal resistance measurement period and a temperature acquisition period between adjacent recharge periods. During the internal resistance measurement period, the monitoring module obtains the internal resistance of the individual battery cell of the object to be recharged via the internal resistance measurement module; during the temperature acquisition period, it obtains the temperature of the individual battery cell of the object to be recharged via the temperature acquisition module. When the temperature of the individual battery cell of the object to be recharged enters the current-reducing range below the charging temperature limit, the monitoring module configures the balancing current of the next recharge period to a low-level charging current. When the temperature of the individual battery cell of the object to be recharged is equal to or higher than the charging temperature limit, the monitoring module disconnects the switching circuit.

[0010] Furthermore, during the period when the monitoring module controls the equalization charging module or equalization discharging module to connect to the single battery that needs maintenance, the current acquisition module collects the equalization circuit current, and the monitoring module forms the equalization quantity from the equalization circuit current and the equalization period, and writes the series sequence number, equalization direction, equalization quantity and equalization end voltage of the single battery that needs maintenance into the equalization execution data.

[0011] Furthermore, the switching circuit includes a positive relay group, a negative relay group, and an equalization circuit relay. The positive relay group is connected to the positive terminal of each individual battery cell, the negative relay group is connected to the negative terminal of each individual battery cell, and the equalization circuit relay is connected in series in the output circuit of the equalization charging module or equalization discharging module. After the monitoring module closes the corresponding positive and negative relays according to the series connection position of the individual battery cell to be maintained, it acquires the verification voltage across the individual battery cell to be maintained through the voltage acquisition module and acquires the zero-point current of the equalization circuit through the current acquisition module. When the polarity of the verification voltage matches the polarity of the individual battery cell to be maintained and the zero-point current of the equalization circuit is within the zero-point calibration range of the current acquisition module, the monitoring module closes the equalization circuit relay.

[0012] Furthermore, the internal resistance measurement module includes an AC current injection unit and a voltage response sampling unit. The AC current injection unit is connected to the tested individual battery cell via an independent current line, and the voltage response sampling unit is connected to the tested individual battery cell via an independent sampling line. The monitoring module calculates the internal resistance of the individual battery cell based on the AC injection current and the terminal voltage response with the same frequency as the AC injection current.

[0013] Furthermore, the monitoring module includes a lower-level equalization processing module, and the lead-acid battery pack equalization management device also includes an industrial control touch screen and a communication module. The industrial control touch screen is connected to the lower-level equalization processing module via the communication module. The lower-level equalization processing module is connected to a voltage acquisition module, a current acquisition module, an internal resistance measurement module, a temperature acquisition module, and a switching circuit. The communication module uses an RS485 bus to transmit inspection requests, parameter configuration data, module addresses, acquired data, and equalization execution data. When no inspection request is received, the lower-level equalization processing module stores local inspection data according to its local inspection cycle, and uploads the module address, local inspection data, and equalization execution data to the industrial control touch screen in Modbus message format after communication is restored.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] By collecting data on individual battery voltage, internal resistance, and temperature within the same inspection cycle, and determining the individual batteries requiring maintenance and the balancing direction based on voltage deviation, the charging and discharging components in the series-connected battery bank can be distinguished online, reducing the risk of continuously widening individual differences.

[0016] By combining the internal resistance deviation and the temperature of individual batteries, the equalization current and equalization period are determined, so that individual batteries with high internal resistance or limited temperature can obtain corresponding current and time control during supplementary charging or discharging, thereby reducing the impact of overcharging, over-discharging and abnormal heating on the battery pack life.

[0017] By switching the circuit to connect the equalization charging module or equalization discharging module to both ends of the single battery cell that needs maintenance, and verifying the voltage and zero-point current of the equalization circuit before closing the equalization circuit relay, the risk of relay misconnection, abnormal polarity, and abnormal load connection is reduced.

[0018] By recording the equalization charge, the equalization end voltage, and the data uploaded via communication, the battery pack equalization maintenance process has a traceable data foundation, which helps to improve the available capacity of the battery pack and the reliability of operation and maintenance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a lead-acid battery pack equalization management device.

[0020] Figure 2 The circuit diagram shows the switching circuit and the equalization charging / discharging circuit.

[0021] Figure 3 This is a schematic diagram of Modbus communication interaction. Detailed Implementation

[0022] This embodiment provides a lead-acid battery pack equalization management device, suitable for use with... A lead-acid battery pack is formed by connecting individual batteries in series. The number of individual batteries written in the device parameter area, with each individual battery numbered from Section 1 to Section 2 according to the series electrical sequence. Section, the series serial number of any single battery cell is based on express, From 1 to Integers in the range.

[0023] like Figure 1 As shown, a lead-acid battery pack balancing management device includes a voltage acquisition module, a current acquisition module, an internal resistance measurement module, a temperature acquisition module, a monitoring module, a balancing charging module, a balancing discharging module, and a switching circuit. The voltage acquisition module is connected to the voltage sampling channel of each individual battery cell. The current acquisition module is located in the balancing loop of the balancing charging and discharging modules. The internal resistance measurement module is connected to the internal resistance measurement channel of each individual battery cell. The temperature acquisition module is connected to the temperature sensor corresponding to each individual battery cell. The switching circuit connects the balancing charging module, the balancing discharging module, and each individual battery cell.

[0024] The monitoring module reads the data uploaded by each acquisition module according to the inspection cycle and stores the inspection data according to the series sequence number of each individual battery. Within the inspection cycle, the first The voltage of a single battery cell is It means that the first The internal resistance of a single battery cell is reduced. It means that the first Temperature of individual battery cells express. This is the inspection count value. Data is acquired by the voltage acquisition module. Measured by the internal resistance measurement module, Data is collected by the temperature acquisition module.

[0025] The voltage acquisition module, internal resistance measurement module, and temperature acquisition module send the voltage, internal resistance, and temperature of each individual battery cell to the monitoring module within the same inspection cycle. The monitoring module completes the checks from section 1 to section 2 within the same inspection cycle. After receiving data from individual battery cells, the data is converted into inspection count values. The corresponding inspection data group includes a serial number. Single battery voltage Internal resistance of a single battery and individual battery temperature .

[0026] The current acquisition module sends the balancing loop current to the monitoring module during supplementary charging or discharging. When a single battery cell is being supplemented with charge or discharged, the first... The equalization loop current at each sampling point is express, This refers to the current sampling sequence number during the equalization execution. The current sampling period is... express, Write the current to the sampling register of the current acquisition module and include it in the equalization power calculation on an hourly basis.

[0027] The internal resistance measurement module includes an AC current injection unit and a voltage response sampling unit. The AC current injection unit is connected to the tested individual battery cell via an independent current line, and the voltage response sampling unit is connected to the tested individual battery cell via an independent sampling line. The independent current line applies AC injection current to the tested individual battery cell, and the independent sampling line acquires the terminal voltage response across the tested individual battery cell. The separate arrangement of the current injection channel and the voltage sampling channel helps reduce the impact of voltage drop across the connection lines on the terminal voltage response sampling results.

[0028] During internal resistance measurement, the AC current injection unit output injection frequency is: AC injection current, Write the parameter register of the internal resistance measurement module. Sampling frequency. Configured as of times, The number of sampling points per AC cycle. Write to the parameter register of the internal resistance measurement module. The sampling window contains... A complete communication cycle, Write to the parameter register of the internal resistance measurement module. The number of internal resistance measurement sampling points is... express, . No. Each sampling time express, ;No. Each AC injection current sampling value It means that the first Individual terminal voltage response sample value express, From 1 to Integers in the range.

[0029] Before the AC current injection unit starts outputting AC injection current, the monitoring module sends an injection start command to the AC current injection unit; the injection start command simultaneously triggers the current sampling counter and voltage sampling counter to be reset to zero, and the current acquisition channel and voltage sampling channel start acquiring from the same sampling sequence number and acquire continuously. Each sampling point is recorded. For each sampling point acquired, the monitoring module uses the sampling sequence number... and sampling frequency Calculate sampling time And generate the first reference value. Second reference quantity The monitoring module generates the cosine component of the AC injection current at the same frequency according to the following formula. AC injection current sinusoidal component of the same frequency The same frequency cosine component of the terminal voltage response The same frequency sinusoidal component of the terminal voltage response :

[0030] ;

[0031] ;

[0032] ;

[0033] ;

[0034] The monitoring module is based on and Forming AC injection current with the same frequency amplitude , for Square and The square root of the sum of squares; the monitoring module based on and Forming the same frequency amplitude of the terminal voltage response , for Square and The square root of the sum of squares. The monitoring module calculates the internal resistance of a single battery cell based on the AC injection current and the terminal voltage response with the same frequency as the AC injection current. Within the first inspection cycle Internal resistance of single-cell batteries for and The ratio is calculated using the following formula:

[0035] ;

[0036] The monitoring module writes the calculated internal resistance of each individual battery cell into the internal resistance record corresponding to the series sequence number in the current inspection cycle. Sampling window coverage. A complete AC cycle, and the same frequency components are obtained by multiplication and accumulation, which helps to reduce the ripple components in the terminal voltage response that are different from the injection frequency.

[0037] The monitoring module generates a voltage reference value based on the voltage of each individual battery cell within the same inspection cycle, and generates a voltage deviation value based on the deviation of the individual battery cell voltage from the voltage reference value. The voltage reference value for each inspection cycle is based on This indicates that the voltage deviation is expressed as... The calculation formula is as follows:

[0038] ;

[0039] ;

[0040] The monitoring module generates an internal resistance reference value based on the internal resistance of each individual battery cell within the same inspection cycle, and generates an internal resistance deviation value based on the deviation of the individual battery cell's internal resistance from the reference value. The internal resistance reference value for each inspection cycle is based on This indicates that the internal resistance deviation is... The calculation formula is as follows:

[0041] ;

[0042] ;

[0043] When the monitoring module generates voltage deviation and internal resistance deviation, it records the voltage and internal resistance of each individual battery within the same inspection cycle according to their series serial number. The arithmetic mean of the voltages of all individual batteries is used as the voltage reference value, and the arithmetic mean of their internal resistances is used as the internal resistance reference value. The difference between the individual battery voltage and the voltage reference value forms the voltage deviation, and the difference between the individual battery internal resistance and the internal resistance reference value forms the internal resistance deviation. The inspection record includes the inspection count value. Serial number Single battery voltage Internal resistance of a single battery Individual battery temperature Voltage reference value Internal resistance reference value Voltage deviation and internal resistance deviation Both the voltage reference value and the internal resistance reference value are taken from the entire set of individual cell data within the same inspection cycle, which is beneficial for comparing individual cell differences under the same float charge state and the same environmental background.

[0044] The monitoring module determines the individual batteries requiring maintenance and the balancing direction based on voltage deviation. It determines the balancing current and balancing period based on internal resistance deviation and individual battery temperature, and verifies the execution current for supplementary charging or discharging based on the balancing circuit current. The monitoring module also identifies the objects to be supplemented with charging and discharged based on voltage deviation. For objects to be supplemented with charging, the monitoring module determines the supplementary charging current, supplementary charging period, and number of segmented charging cycles based on internal resistance deviation and individual battery temperature. For objects to be discharged, the monitoring module determines the discharge current and discharge period based on internal resistance deviation and individual battery temperature.

[0045] The first constant current charging level is written into the device parameter area of ​​the monitoring module. Second constant current charging level First constant current discharge setting Second constant current discharge setting Charging temperature limit Discharge temperature limit Single-stage charging time Basic discharge duration Temperature protection discharge duration Internal resistance measurement time and temperature acquisition time .

[0046] When the voltage deviation is negative, the monitoring module identifies the corresponding battery cell as a target for supplemental charging; when the voltage deviation is positive, it identifies the corresponding battery cell as a target for discharging. The monitoring module treats both the battery cell requiring supplemental charging and the battery cell requiring discharging as individual batteries and determines the balancing direction based on the type of battery being charged or discharged. Voltage Deviation At this time, the monitoring module does not write the corresponding individual battery cell to the individual battery cell that needs maintenance. Therefore, the equalization charging module acts on the object to be charged, and the equalization discharging module acts on the object to be discharged.

[0047] The charging parameter template includes fields for low-level charging current, high-level charging current, single-stage charging duration, charging temperature limit, and charging downgrade start-up temperature. First constant current charging level. Corresponding to the low-level charging current field, the second constant current charging level. Corresponding to the advanced charging current field, single-segment charging time Corresponding to the single-segment charging time field, charging temperature limit. Corresponding charging temperature limit field. Charging downgrade start-up temperature is... express, and Write the parameters according to the maintenance manual or on-site maintenance table for the same model of battery, and Charging temperature protection advance time for and The difference is calculated using the following formula:

[0048] ;

[0049] The discharge parameter template includes fields for low-level discharge current, high-level discharge current, basic discharge duration, temperature-protected discharge duration, discharge temperature limit, and discharge downgrade start-up temperature. First constant current discharge level. Corresponding to the low-level discharge current field, the second constant current discharge level. Corresponding to the advanced discharge current field, the basic discharge duration Corresponding to the basic discharge duration field, temperature protection discharge duration The corresponding temperature protection discharge duration field, discharge temperature limit. Corresponding discharge temperature limit field. Discharge downgrade start-up temperature is... express, and Write the parameters according to the maintenance manual or on-site maintenance table for the same model of battery, and Discharge temperature protection advance amount for and The difference is calculated using the following formula:

[0050] ;

[0051] The charging and discharging parameter templates are written into the monitoring module via the industrial control touch screen and correspond to the constant current output levels of the equalization charging and equalization discharging modules; the first constant current charging level... Second constant current charging level The constant current output level is taken from the factory parameters of the equalization charging module, specifically the first constant current discharge level. Second constant current discharge level The constant current output level is taken from the factory parameters of the equalization discharge module.

[0052] Internal resistance deviation of the object being charged and At that time, the monitoring module uses the second constant current charging level. and single-stage charging time ; Internal resistance deviation of the object being charged and At that time, the monitoring module uses the first constant current charging level. and single-stage charging time ; At this time, the monitoring module disconnects the switching circuit. The above control path is used for supplementary charging objects whose internal resistance is not higher than the internal resistance reference value.

[0053] When the monitoring module determines that the object to be charged has a positive internal resistance deviation, it configures the equalization period to include at least two charging periods, plus an internal resistance measurement period and a temperature acquisition period between adjacent charging periods. Before performing segmented charging, the monitoring module first reads the temperature of the individual battery cells of the object to be charged. ; At that time, the monitoring module disconnects the switching circuit; At that time, the monitoring module is configured with segmented supplementary charging tasks.

[0054] The internal resistance maintenance parameter field includes an internal resistance warning ratio field. When the maintenance manual for the same model of lead-acid battery specifies the individual cell internal resistance deviation maintenance ratio, it also includes the internal resistance warning ratio. The maintenance ratio for individual cell internal resistance deviation is written according to the data; when the maintenance manual for the same model of lead-acid battery does not specify the maintenance ratio for individual cell internal resistance deviation, the monitoring module reads the acceptance internal resistance of each individual battery cell from the equipment commissioning and acceptance record. Acceptance limit of internal resistance of single battery ,in From 1 to The integer in the value represents the acceptance internal resistance of each individual battery cell. The arithmetic mean was used as the benchmark value for internal resistance during commissioning and acceptance. The calculation formula is:

[0055] ;

[0056] Upper limit of internal resistance for single battery For equipment commissioning and acceptance records, the internal resistance value is higher than the commissioning and acceptance benchmark value. The upper limit of the acceptable internal resistance of a single unit. The monitoring module generates the internal resistance warning ratio according to the following formula. :

[0057] ;

[0058] The monitoring module generates segmented internal resistance values ​​using the following formula. :

[0059] ;

[0060] and At that time, the monitoring module will divide the charging times into segments. Write it as 2, the first segment uses the second constant current charging level. The second stage uses the first constant current charging level. ; and At that time, the monitoring module will divide the charging times into segments. Write it as 2, both supplementary charging periods use the first constant current charging level. ; and At that time, the monitoring module will divide the charging times into segments. Write it as 3, and use the first constant current charging level during each supplementary charging period. The execution duration of each supplementary charging period is configured as a single charging segment duration. .

[0061] Internal resistance measurement time The sampling window duration and relay settling time for a single AC injection measurement are determined by the internal resistance measurement module. The number of complete AC cycles in the AC injection measurement is also determined. and the injection frequency of the AC injection current Write to the parameter register of the internal resistance measurement module; relay settling time is... express, Write the parameters in the device parameter area according to the relay device manual. Internal resistance measurement duration. The formula for calculation is:

[0062] ;

[0063] Temperature acquisition time The switching time of the temperature sensor is determined by the reading time of the monitoring module. The switching time of the temperature sensor is written into the device parameter area according to the temperature sensor device manual. Segmented supplementary charging reads the internal resistance and temperature between adjacent supplementary charging periods, which is beneficial for confirming the intermediate state of high internal resistance individual batteries before they are continuously charged.

[0064] During the internal resistance measurement period, the monitoring module obtains the internal resistance of the individual battery cell being charged through the internal resistance measurement module; during the temperature acquisition period, it obtains the temperature of the individual battery cell being charged through the temperature acquisition module. The intermediate temperature after each supplementary charging period ends is as follows: express, From 1 to Integers in Temperature data is collected by the temperature acquisition module between adjacent supplementary charging periods. Temperature range The current reduction range is below the charging temperature limit. When the temperature of a single battery cell enters the reduced current range below the charging temperature limit, the monitoring module will configure the balancing current for the next charging period to the first constant current charging level. The next charging period has been configured to use the first constant current charging mode. At that time, the monitoring module maintains the first constant current charging level. When the temperature of a single battery cell being charged is equal to or higher than the charging temperature limit, the monitoring module disconnects the switching circuit. When disconnecting the switching circuit, the monitoring module first disconnects the balancing circuit relay, then disconnects the corresponding positive and negative relays.

[0065] When the object being discharged enters the discharge process, the monitoring module determines the discharge current and discharge period based on the deviation of the object's internal resistance and the temperature of the individual battery cells. and At that time, the monitoring module uses the second constant current discharge setting. and basic discharge duration ; Deviation of internal resistance of the object being discharged and At that time, the monitoring module uses the first constant current discharge setting. and temperature protection discharge duration ; At that time, the monitoring module uses the first constant current discharge setting. and temperature protection discharge duration ; At this time, the monitoring module disconnects the switching circuit. Temperature protection discharge duration. Less than the basic discharge duration When the internal resistance deviation of the object being discharged is positive, using the first constant current discharge setting and the temperature protection discharge duration helps reduce the heat accumulation of high internal resistance individual batteries during discharge maintenance.

[0066] like Figure 2 As shown, the switching circuit includes a positive relay group, a negative relay group, and an equalization circuit relay. The positive relay group is connected to the positive terminal of each individual battery cell, the negative relay group is connected to the negative terminal of each individual battery cell, and the equalization circuit relay is connected in series in the output circuit of the equalization charging module or equalization discharging module. The positive relay group includes... A positive relay and a negative relay group include... Each negative relay, positive relay, and negative relay is set according to the series sequence number of the individual battery cells. The switching circuit connects the equalization charging module or equalization discharging module to the two ends of the individual battery cell to be maintained according to its series position and performs supplementary charging or discharging.

[0067] The corresponding number of individual batteries that need maintenance When a single battery cell is connected, the monitoring module closes the first... The positive relay and the first One negative relay and one equalization circuit relay remain open. After the monitoring module closes the corresponding positive and negative relays according to the series connection position of the individual battery to be maintained, it acquires the verification voltage across the individual battery through the voltage acquisition module and the zero-point current of the equalization circuit through the current acquisition module. When the polarity of the verification voltage matches that of the individual battery to be maintained and the zero-point current of the equalization circuit is within the zero-point calibration range of the current acquisition module, the monitoring module closes the equalization circuit relay.

[0068] Verification voltage This indicates that the voltage acquisition module uses the positive terminal of the individual battery cell requiring maintenance as the calibration positive sampling terminal, and the negative terminal of the individual battery cell requiring maintenance as the calibration negative sampling terminal. The first time the equalization circuit relay is in the off state The voltage across the terminals of a single battery cell. The zero-point current of the balancing circuit. express, This refers to the current value output by the current acquisition module when the equalization circuit relay is disconnected. The specific determination is as follows: ,and It is located within the zero-point calibration range of the current acquisition module. Closing the equalization circuit relay after polarity verification and zero-point current verification helps reduce the risk of incorrect load connection caused by reverse polarity connection, relay sticking, or sampling zero-point drift.

[0069] The calibration process for the current acquisition module includes zero-point calibration and standard current calibration. During zero-point calibration, the equalization circuit relay is disconnected, the equalization charging module and the equalization discharging module stop outputting, and the current acquisition module continuously acquires current. Zero-point current samples. Write it according to the zero-point sample quantity field in the calibration parameter area. Zero-point current sample express, From 1 to Integers in the range. After sorting the zero-point current samples in ascending order of their values, the first item is... It means that the first Item with Indicated. The range of the current acquisition module is as follows: This indicates that the number of bits in the analog-to-digital conversion is... Indicates current resolution The formula for calculation is:

[0070] ;

[0071] Zero point calibration range is ,therefore At that time, the zero-point current of the equalization circuit is within the zero-point calibration range of the current acquisition module.

[0072] During standard current calibration, the current acquisition module is connected to a standard current source. Standard current. The standard current is the output current amplitude of the standard current source; when calibrating the equalization charging module, the standard current... Take the second constant current charging level The corresponding standard current; the standard current when calibrating the equalization discharge module. Select the second constant current discharge setting. The corresponding standard current. The current acquisition module continuously acquires data. The first standard current sample, the... A standard current sample express, The arithmetic mean of the absolute values ​​of the standard current samples is... This indicates the standard current error. and execution current verification limit The formula for calculation is:

[0073] ;

[0074] ;

[0075] ;

[0076] The zero-point calibration range and the execution current verification limit are both formed by measured samples, standard current values, ranges, and analog-to-digital conversion bits, which helps to provide a unified calibration benchmark for zero-point judgment and execution current judgment of the equalization circuit.

[0077] After the equalization charging module or equalization discharging module is connected to the individual battery requiring maintenance, the target equalization current is as follows: express, The current amplitude of the constant current charging or discharging level selected for the monitoring module. The positive direction of the current acquisition module is set according to the direction of the output current from the equalization charging module to the individual battery requiring maintenance; the equalization direction is for supplementary charging. This indicates that the direction of the current in the balancing circuit is the same as the direction of the supplementary charging; when the balancing direction is during discharge, This indicates that the direction of the current in the balancing circuit is the same as the direction of discharge. The execution current deviation of each sampling point is The calculation formula is as follows:

[0078] ;

[0079] When the monitoring module performs current verification, the current direction of the balancing loop current is consistent with the balancing direction and When the current direction of the equalization circuit current is inconsistent with the equalization direction, the monitoring module will disconnect the switching circuit and write an abnormal current direction record. At that time, the monitoring module disconnects the switching circuit and writes an abnormal current amplitude record.

[0080] During the period when the monitoring module controls the equalization charging module or equalization discharging module to connect to the individual battery requiring maintenance, the current acquisition module collects the equalization circuit current. The monitoring module calculates the equalization charge based on the equalization circuit current and the equalization period, and writes the series sequence number, equalization direction, equalization charge, and equalization end voltage of the individual battery requiring maintenance into the equalization execution data. The number of current sampling points in one equalization process is... express, This represents the number of sampling points during the period from the closing to the opening of the equalization circuit relay. The primary equalization charge of a single battery cell is as follows: express, The unit is Ah, and the calculation formula is:

[0081] ;

[0082] After the equalization circuit relay is disconnected, the voltage acquisition module acquires the first... The voltage of a single battery cell is used as the equalization termination voltage. The balancing execution data includes the series sequence number of the individual battery cells to be maintained, the balancing direction, the balancing capacity, and the balancing termination voltage.

[0083] The monitoring module includes a lower-level equalization processing module. The lead-acid battery pack equalization management device also includes an industrial control touch screen and a communication module. The industrial control touch screen communicates with the lower-level equalization processing module via the communication module. The lower-level equalization processing module is connected to a voltage acquisition module, a current acquisition module, an internal resistance measurement module, a temperature acquisition module, and a switching circuit. The lower-level equalization processing module completes the tasks of receiving inspection data, calculating deviation, generating equalization tasks, relay control, recording equalization execution data, and storing local inspection data.

[0084] like Figure 3 As shown, the communication module uses an RS485 bus to transmit inspection requests, parameter configuration data, module address, acquired data, and equalization execution data. The Modbus message on the RS485 bus includes the module address, function code, register address, data field, and CRC check field. Inspection requests are written to the inspection register address, parameter configuration data is written to the parameter register address, acquired data is written to the voltage register, internal resistance register, temperature register, and current register, and equalization execution data is written to the equalization record register.

[0085] The lower-level load balancing module stores local inspection data according to the local inspection cycle when no inspection request is received. The local inspection cycle is based on... express, The inspection cycle field in the local inspection parameters is written to the cycle register of the lower-level equalization processing module. The cycle for the industrial control touch screen to send inspection requests is... express, Write to the communication parameter area, and The timer in the lower-level equalization processing module accumulates to... When the RS485 bus does not receive an inspection request message, the lower-level equalization processing module performs a local inspection, writing the module address, inspection count value, individual battery voltage, individual battery internal resistance, individual battery temperature and equalization execution data into the local storage area. Then the timer is cleared and the next local inspection cycle begins.

[0086] After communication is restored, the lower-level equalization processing module uploads its module address, local inspection data, and equalization execution data to the industrial control touchscreen display in Modbus message format. Communication restoration is confirmed when the RS485 bus receives an inspection request message containing the module's address and with a correct CRC checksum. The data fields of the uploaded message are sequentially written as: module address, inspection count value, individual battery voltage, individual battery internal resistance, individual battery temperature, equalization direction, equalization charge, and equalization termination voltage. The industrial control touchscreen display shows and stores the corresponding data according to the module address. This combination of local storage by the lower-level equalization processing module and uploading after communication restoration helps retain inspection data and equalization execution data during RS485 bus interruptions.

[0087] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A lead-acid battery pack balancing management device, characterized in that, The system includes a voltage acquisition module, a current acquisition module, an internal resistance measurement module, a temperature acquisition module, a monitoring module, an equalization charging module, an equalization discharging module, and a switching circuit. The voltage acquisition module, internal resistance measurement module, and temperature acquisition module send the voltage, internal resistance, and temperature of each individual battery cell to the monitoring module within the same inspection cycle. The current acquisition module sends the equalization circuit current to the monitoring module during supplementary charging or discharging. The monitoring module generates a voltage reference value based on the voltage of each individual battery cell within the same inspection cycle, and generates a voltage deviation value based on the deviation of the individual battery cell voltage from the voltage reference value. Similarly, the monitoring module generates an internal resistance reference value based on the internal resistance of each individual battery cell within the same inspection cycle, and generates an internal resistance deviation value based on the deviation of the individual battery cell internal resistance from the internal resistance reference value. The monitoring module determines the individual battery to be maintained and the balancing direction based on the voltage deviation, determines the balancing current and balancing period based on the internal resistance deviation and the temperature of the individual battery, and verifies the execution current for supplementary charging or discharging based on the balancing circuit current; the switching circuit connects the balancing charging module or balancing discharging module to the two ends of the individual battery to be maintained according to the series connection position of the individual battery to be maintained and performs supplementary charging or discharging.

2. The lead-acid battery pack equalization management device according to claim 1, characterized in that, When the monitoring module generates voltage deviation and internal resistance deviation, it records the voltage and internal resistance of individual batteries within the same inspection cycle according to the series serial number of each individual battery. The arithmetic mean of the voltage of each individual battery is used as the voltage reference value, and the arithmetic mean of the internal resistance of each individual battery is used as the internal resistance reference value. The difference between the individual battery voltage and the voltage reference value is used to generate the voltage deviation, and the difference between the individual battery internal resistance and the internal resistance reference value is used to generate the internal resistance deviation.

3. The lead-acid battery pack equalization management device according to claim 2, characterized in that, When the voltage deviation is negative, the monitoring module identifies the corresponding single battery cell as a target for supplemental charging; when the voltage deviation is positive, the monitoring module identifies the corresponding single battery cell as a target for discharge. The monitoring module identifies the target for supplemental charging and the target for discharge as single batteries that need maintenance, and determines the balancing direction according to the target for supplemental charging or discharge.

4. The lead-acid battery pack equalization management device according to claim 3, characterized in that, When the monitoring module determines that the object to be recharged is positive and the internal resistance deviation of the object to be recharged is positive, the equalization period is configured as at least two recharge periods, as well as the internal resistance measurement period and temperature acquisition period between adjacent recharge periods.

5. The lead-acid battery pack equalization management device according to claim 4, characterized in that, During the internal resistance measurement period, the monitoring module obtains the internal resistance of the individual battery of the object to be recharged through the internal resistance measurement module, and during the temperature acquisition period, it obtains the temperature of the individual battery of the object to be recharged through the temperature acquisition module. When the temperature of the individual battery of the object to be recharged enters the current reduction range below the charging temperature limit, the monitoring module configures the equalization current of the next recharge period to the low-level charging current. When the temperature of the individual battery of the object to be recharged is equal to or higher than the charging temperature limit, the monitoring module disconnects the switching circuit.

6. The lead-acid battery pack equalization management device according to claim 1, characterized in that, When the monitoring module controls the equalization charging module or equalization discharging module to connect to the single battery to be maintained, the current acquisition module collects the equalization circuit current. The monitoring module forms the equalization charge from the equalization circuit current and the equalization period, and writes the series sequence number, equalization direction, equalization charge and equalization end voltage of the single battery to be maintained into the equalization execution data.

7. The lead-acid battery pack equalization management device according to claim 1, characterized in that, The switching circuit includes a positive relay group, a negative relay group, and an equalization circuit relay. The positive relay group is connected to the positive terminal of each individual battery, the negative relay group is connected to the negative terminal of each individual battery, and the equalization circuit relay is connected in series in the output circuit of the equalization charging module or the equalization discharging module.

8. The lead-acid battery pack equalization management device according to claim 7, characterized in that, After the monitoring module closes the corresponding positive and negative relays according to the series connection position of the individual battery to be maintained, it collects the verification voltage across the individual battery through the voltage acquisition module and the zero-point current of the balancing circuit through the current acquisition module. When the polarity of the verification voltage is consistent with the polarity of the individual battery to be maintained and the zero-point current of the balancing circuit is within the zero-point calibration range of the current acquisition module, the monitoring module closes the balancing circuit relay.

9. The lead-acid battery pack equalization management device according to claim 1, characterized in that, The internal resistance measurement module includes an AC current injection unit and a voltage response sampling unit. The AC current injection unit is connected to the tested individual battery cell through an independent current line, and the voltage response sampling unit is connected to the tested individual battery cell through an independent sampling line. The monitoring module calculates the internal resistance of the individual battery cell based on the AC injection current and the terminal voltage response with the same frequency as the AC injection current.

10. A lead-acid battery pack equalization management device according to claim 1, characterized in that, The monitoring module includes a lower-level equalization processing module. The lead-acid battery pack equalization management device also includes an industrial control touch screen and a communication module. The industrial control touch screen is connected to the lower-level equalization processing module via the communication module. The lower-level equalization processing module is connected to a voltage acquisition module, a current acquisition module, an internal resistance measurement module, a temperature acquisition module, and a switching circuit. The communication module uses an RS485 bus to transmit inspection requests, parameter configuration data, module addresses, acquired data, and equalization execution data. When no inspection request is received, the lower-level equalization processing module stores local inspection data according to the local inspection cycle. After communication is restored, it uploads the module address, local inspection data, and equalization execution data to the industrial control touch screen in Modbus message format.

Images