Interpack equalization power transfer system and method for a battery pack

Abstract

The application discloses a kind of inter-battery equalization power transmission system and method of battery pack, it is related to battery management technical field, the method includes: each slave control module real-time data acquisition, and upload to main control module;Main control module each battery pack health state and corresponding dc converter operating efficiency, for each battery pack allocation dynamic weight factor, generate dynamic optimal bus voltage reference value, and control main converter will public dc bus voltage be adjusted to reference value;When determining that inter-battery energy transmission is needed, energy transmission instruction is issued to relevant slave control module;The expected performance of direct energy transmission path and through relay battery pack is analyzed to carry out relay energy transmission path, the path with higher expected performance is selected as the final energy transmission scheme, and is issued to relevant slave control module;Slave control module generates charge-discharge control instruction according to energy transmission scheme, and completes equalization power transmission.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, specifically to a battery pack inter-pack equalization power transmission system and method. Background Technology

[0002] In fields such as new energy storage and electric vehicles, multiple battery packs are typically connected in series or parallel to meet power and capacity requirements. However, during long-term charge-discharge cycles, battery packs are prone to inconsistencies in state of charge (SOC), state of health (SOH), and terminal voltage due to factors such as manufacturing processes, operating environment, and aging. Without equalization control, some battery packs may be overcharged or over-discharged, shortening their overall lifespan and even posing safety risks. Existing inter-pack equalization technologies mostly use fixed bus voltage or a single direct transmission path, failing to consider the dynamic changes in battery pack health and converter operating efficiency, resulting in low equalization efficiency and high energy loss. While some technologies introduce relay transmission, they lack quantitative analysis and dynamic selection mechanisms for path efficiency and do not establish a complete closed-loop compensation system for efficiency deviations. This makes it difficult to adapt to the dynamic equalization requirements under complex operating conditions and to balance equalization effectiveness with long-term system stability. Summary of the Invention

[0003] The purpose of this invention is to provide a battery pack inter-pack equalization power transmission system and method to solve the problems raised in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for inter-pack equalization power transfer in a battery pack, the method comprising:

[0005] S100: Each slave control module collects the voltage information, state of charge information, health status information of the corresponding battery pack and the operating efficiency data of each bidirectional isolated DC-DC converter in real time, and uploads them to the main control module.

[0006] The S200 main control module uses the health status of each battery pack and the operating efficiency of the corresponding DC-DC converter to assign a dynamic weighting factor to each battery pack. Based on the voltage values ​​of all battery packs and the corresponding dynamic weighting factors, it generates a dynamic optimal bus voltage reference value and controls the main converter to adjust the common DC bus voltage to the optimal bus voltage reference value.

[0007] S300: Based on the dynamic optimal bus voltage reference value and the status of each battery pack, the main control module determines when inter-pack energy transfer is required and issues an energy transfer command to the relevant slave control module; it analyzes the expected efficiency of the direct energy transfer path between the source battery pack and the target battery pack and the relay energy transfer path through the relay battery pack; it analyzes the expected efficiency, selects the path with higher expected efficiency as the final energy transfer scheme, and issues it to the relevant slave control module.

[0008] S400: Upon receiving the path decision, the slave control module generates charging and discharging control commands based on the energy transmission scheme, adjusts the phase shift angle of the corresponding DC-DC converter, and completes balanced power transmission.

[0009] S500: Each slave control module feeds back the actual transmission performance to the main control module. The main control module compares the deviation between the actual transmission performance and the expected performance. When the deviation exceeds the preset threshold, it compensates by correcting the dynamic weighting factor or instructing the slave control module to adjust the phase angle adjustment parameter.

[0010] According to the above scheme, step S200 includes:

[0011] S210: The main control module assigns a dynamic weighting factor to each battery pack. The weighting factor is determined by the health status of the battery pack and the real-time operating efficiency of its corresponding DC-DC converter, as shown in the following formula:

[0012] W i =f(SOH i ,η i );

[0013] Among them, W i SOH represents the dynamic weighting factor corresponding to the i-th battery pack; i represents the index of the battery pack; i This represents the health status of the i-th battery pack; η i Let f represent the real-time operating efficiency of the DC-DC converter corresponding to the i-th battery pack; f represents the positive correlation function between the health status of the battery pack and the real-time operating efficiency of the corresponding DC-DC converter.

[0014] S220: The main control module calculates the weighted average of the voltage values ​​of all battery packs and uses this weighted average as the reference value for the dynamic optimal bus voltage. The formula is as follows:

[0015] ;

[0016] in, Represented as the dynamic optimal bus voltage reference value; V i W represents the voltage value of the i-th battery pack. i Let represent the dynamic weighting factor corresponding to the i-th battery pack; n represents the total number of battery packs.

[0017] S230, the main control module controls the main converter, adjusts the phase shift angle of the internal switching transistors of the main converter, and adjusts the common DC bus voltage to the dynamic optimal bus voltage reference value.

[0018] According to the above scheme, step S300 includes:

[0019] S310 The main control module calculates the absolute value of the deviation between the voltage value of each battery pack and the dynamic optimal bus voltage reference value. When the absolute value of the deviation exceeds the preset voltage deviation threshold, it is determined that inter-pack energy transfer needs to be performed.

[0020] S320: The main control module determines the target battery pack that needs to be replenished or absorb energy and the corresponding source battery pack, and sends an energy transfer command to the slave control module that manages the target battery pack and the source battery pack.

[0021] S330, the main control module calculates the expected efficiency of the direct energy transfer path from the source battery pack to the target battery pack, using the following formula:

[0022] η direct =η source ×η target ;

[0023] Where, η direct表示 Expected performance of direct energy transfer paths; η source Indicates the real-time operating efficiency of the DC-DC converter corresponding to the source battery pack; η target This indicates the real-time operating efficiency of the DC-DC converter corresponding to the target battery pack;

[0024] S340. The main control module selects battery packs with a state of charge within a preset normal range from all battery packs as candidate relay battery packs, and calculates the expected efficiency of the relay energy transmission path through the relay battery packs, as shown in the following formula:

[0025] η relay,k =η source ×η k 2 ×η target ;

[0026] Where, η relay,k η represents the expected efficiency of relay transmission via the k-th relay battery pack; k This represents the real-time operating efficiency of the DC-DC converter corresponding to the k-th relay battery pack; k represents the index of the relay battery pack.

[0027] S350: The main control module compares the expected performance of the direct energy transmission path with the maximum expected performance among all candidate relay transmission paths, and selects the path with higher expected performance as the final energy transmission scheme.

[0028] S360: The main control module sends the final energy transmission scheme to the slave control modules that manage the source battery pack, target battery pack, and relay battery pack.

[0029] Based on the above scheme, it is determined that inter-group energy transfer needs to be performed, including:

[0030] Calculate the terminal voltage V of each battery pack. i With V ref Voltage deviation ΔV i =|V i -V ref |;

[0031] If the voltage deviation of at least one group of batteries exceeds the preset voltage deviation threshold, or if the state of charge difference between at least two groups of batteries exceeds the preset state of charge deviation threshold, then it is determined that inter-group energy transfer needs to be performed.

[0032] Based on the judgment result, the main control module determines the source battery pack and target battery pack for energy transmission, and issues energy transmission instructions to the corresponding slave control modules of the source battery pack and target battery pack. The energy transmission instructions include the source battery pack number, target battery pack number, relay battery pack number, and initial transmission power requirement.

[0033] According to the above scheme, step S400 includes:

[0034] S410. After receiving the final energy transmission scheme from the main control module, the slave control module generates corresponding charging and discharging control commands based on the path type and power allocation rules in the scheme.

[0035] S420. When the energy transmission scheme is a direct energy transmission path, the slave control module that manages the source battery pack generates a discharge control command, which includes the target discharge power of the source battery pack; the slave control module that manages the target battery pack generates a charging control command, which includes the target charging power of the target battery pack, and the target charging power matches the target discharge power of the source battery pack.

[0036] When the energy transmission scheme is a relay transmission path, the slave control module that manages the source battery pack generates a discharge control command, the slave control module that manages the relay battery pack first generates a charging control command, and then generates a discharge control command after the relay battery pack has completed energy reception, and the slave control module that manages the target battery pack generates a charging control command.

[0037] S430: Each slave control module adjusts the output power of the converter by controlling the phase shift angle according to the generated charge and discharge control command, so that the source battery pack discharges at the target discharge power and the target battery pack charges at the target charging power, thus completing the balanced power transfer between battery packs.

[0038] According to the above scheme, step S500 includes:

[0039] S510: Each slave control module collects data in real time and feeds back the actual transmission performance to the main control module;

[0040] S520: After receiving the overall actual transmission performance feedback from each slave control module, the main control module retrieves the expected performance of the corresponding path and analyzes the performance deviation, using the following formula:

[0041] ;

[0042] Where Δη represents the relative deviation between the actual transmission performance and the expected performance; η act Represented as the overall actual transmission performance; η exp This represents the expected performance of the corresponding path;

[0043] S530: When the deviation does not exceed the preset performance deviation threshold, the current transmission status is determined to be normal, no compensation is required, and the existing charging and discharging control command is maintained.

[0044] S540. When the deviation exceeds the preset performance deviation threshold, the main control module initiates a compensation mechanism. The compensation mechanism includes: if the deviation is caused by changes in the health status of the battery pack, the main control module re-corrects the dynamic weighting factors of each battery pack, and based on the corrected dynamic weighting factors, recalculates the dynamic optimal bus voltage reference value and issues a new voltage adjustment command to the main converter; if the deviation is caused by fluctuations in the converter's operating status, the main control module issues a phase shift angle adjustment parameter correction command to the corresponding slave control module, instructing the slave control module to adjust the phase shift angle increment of the converter switching transistors until the deviation drops to within the preset threshold.

[0045] According to the above scheme, step S510 includes:

[0046] During the power equalization process, each control module collects the input and output power of the corresponding bidirectional isolation DC-DC converter in real time and analyzes the actual operating efficiency of the converter, as shown in the following formula:

[0047] ;

[0048] Where, η act,m P represents the actual operating efficiency of the m-th converter, i.e., the actual energy transfer efficiency of the converter; in,m P represents the input power of the m-th converter, i.e., the electrical power received by the converter; out,m This is expressed as the output power of the m-th converter, that is, the electrical power output by the converter;

[0049] Each control module analyzes the overall actual transmission performance based on the transmission path type, using the following formula:

[0050] η act,dir =η act,s ×η act,t ;

[0051] η act,relay =ηact,s ×η act,k ×η act,t ;

[0052] Where, η act,dir Represented as the actual transmission efficiency of a direct energy transmission path; η act,s η represents the actual efficiency of the source battery pack converter. act,t η represents the actual efficiency of the target battery pack converter. act,relay This represents the actual transmission efficiency of the relay transmission path; η act,k This represents the actual efficiency of the relay battery pack converter.

[0053] Each slave control module uploads the calculated overall actual transmission performance to the main control module.

[0054] A battery pack inter-pack equalization power transmission system, the system comprising: an optimization and decision-making module, a power regulation module, a power execution module, a data acquisition module, and an efficiency monitoring module;

[0055] The data acquisition module collects real-time data on battery pack status, converter operation, and bus voltage, and transmits this data to the optimization and decision-making module. The optimization and decision-making module receives all uploaded data, executes global calculations and optimization algorithms, and generates system-level control objectives and strategies. The power regulation module receives the strategy schemes from the optimization and decision-making module and converts them into specific, executable hardware-level control signals to drive the power converter to perform energy transfer. The power execution module completes bidirectional and isolated energy transfer based on the received control signals. The performance monitoring module monitors the actual energy transfer effect in real-time and compares it with the expected target; when a deviation occurs, it automatically triggers a compensation mechanism.

[0056] According to the above scheme, the optimization and decision-making module includes a weight allocation module, a reference value generation module, and a path performance analysis module. The weight allocation module assigns dynamic weight factors to the battery packs based on their health status and the real-time operating efficiency of their corresponding DC-DC converters. The reference value generation module obtains the dynamically optimal bus voltage reference value based on the voltage of all battery packs and their dynamic weights. The path performance analysis module analyzes the expected performance of direct and relay transmission paths and selects the path with the highest performance as the final scheme.

[0057] The power regulation module includes an instruction parsing module and a control signal generation module. The instruction parsing module parses the path type, power level, source battery pack, target battery pack, and relay battery pack numbering information in the energy transmission scheme. The control signal generation module generates specific pulse width modulation or phase shift control signals according to the instructions and sends them to the corresponding DC-DC converter.

[0058] The power execution module includes a bidirectional isolation converter corresponding to the battery pack, which achieves bidirectional energy transmission and electrical isolation through phase shift control of the switching transistor.

[0059] According to the above scheme, the performance monitoring module includes an actual performance analysis module, a deviation analysis module, and a compensation execution module; the actual performance analysis module calculates the efficiency of each converter and the actual performance of the overall transmission path in real time; the deviation analysis module calculates the relative deviation and determines whether compensation is needed; the compensation execution module selects to compensate by correcting the global weighting factor or adjusting the local phase shift angle parameter, depending on the battery pack or converter with the deviation.

[0060] Compared with the prior art, the beneficial effects of the present invention are:

[0061] 1. This invention allocates dynamic weighting factors based on the battery pack health status and the real-time efficiency of the converter to generate a dynamic optimal bus voltage reference value. At the same time, it selects the optimal path by quantitatively analyzing the expected efficiency of direct and relay transmission paths, avoiding energy loss caused by fixed parameters and single paths, improving the overall efficiency of inter-pack balance, and reducing system energy consumption.

[0062] 2. This invention determines the balance requirement from multiple dimensions to avoid the battery pack aging accelerated by overcharging and over-discharging; and uses dynamic weighting factors to prioritize the participation of battery packs in better health in energy transmission, reducing the burden on battery packs in poor health, effectively slowing down the aging rate of the overall battery pack and extending its service life.

[0063] 3. This invention compares the actual and expected transmission performance in real time, and compensates for changes in battery status or fluctuations in the converter by correcting the weighting factor or adjusting the phase shift angle, so as to avoid control inaccuracies caused by the accumulation of balance deviations and ensure that the system can operate stably and reliably under complex conditions. Attached Figure Description

[0064] Figure 1 This is a flowchart of the steps of a battery pack inter-pack equalization power transfer method according to the present invention.

[0065] Figure 2 This is a schematic diagram of the structure of an inter-pack equalization power transmission system for a battery pack according to the present invention. Detailed Implementation

[0066] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] Example: Figures 1-2 As shown, the present invention provides a technical solution, a method for inter-pack power equalization transmission in battery packs, the method comprising the following steps:

[0068] S100: Each slave control module collects the voltage information, state of charge information, health status information of the corresponding battery pack and the operating efficiency data of each bidirectional isolated DC-DC converter in real time, and uploads them to the main control module.

[0069] For example: The power battery system of an electric vehicle contains 3 sets of lithium iron phosphate battery packs, numbered 1, 2 and 3, each with a rated capacity of 100Ah and a rated voltage of 3.2V; 3 bidirectional isolation converters, each corresponding to one of the 3 battery packs, with a rated power of 5kW; 1 main control module; 3 slave control modules, each managing battery packs 1, 2 and 3 respectively; and 1 common DC bus.

[0070] Each slave control module collects data from the corresponding battery pack and converter in real time and uploads it to the main control module. The collected data is as follows:

[0071] Battery pack 1: Voltage V1=3.3V, SOC1=85%, SOH1=0.9 (good health), corresponding converter efficiency η1=0.96; Battery pack 2: Voltage V2=3.1V, SOC2=75%, SOH2=0.85 (moderate health), corresponding converter efficiency η2=0.95; Battery pack 3: Voltage V3=3.2V, SOC3=80%, SOH3=0.88 (good health), corresponding converter efficiency η3=0.97; Current voltage of the common DC bus = 3.2V.

[0072] The S200 main control module uses the health status of each battery pack and the operating efficiency of the corresponding DC-DC converter to assign a dynamic weighting factor to each battery pack. Based on the voltage values ​​of all battery packs and the corresponding dynamic weighting factors, it generates a dynamic optimal bus voltage reference value and controls the main converter to adjust the common DC bus voltage to the optimal bus voltage reference value.

[0073] Specifically, step S200 includes:

[0074] S210: The main control module assigns a dynamic weighting factor to each battery pack. The weighting factor is determined by the health status of the battery pack and the real-time operating efficiency of its corresponding DC-DC converter, as shown in the following formula:

[0075] W i =f(SOH i ,η i );

[0076] Among them, W i SOH represents the dynamic weighting factor corresponding to the i-th battery pack; i represents the index of the battery pack;i This represents the health status of the i-th battery pack; η i Let f represent the real-time operating efficiency of the DC-DC converter corresponding to the i-th battery pack; f represents the positive correlation function between the health status of the battery pack and the real-time operating efficiency of the corresponding DC-DC converter.

[0077] For example: The main control module uses a linear positive correlation function to allocate dynamic weight factors.

[0078] The weight of battery pack 1 is W1 = 0.5 × 0.9 + 0.5 × 0.96 = 0.93; the weight of battery pack 2 is W2 = 0.5 × 0.85 + 0.5 × 0.95 = 0.9; the weight of battery pack 3 is W3 = 0.5 × 0.88 + 0.5 × 0.97 = 0.925.

[0079] S220: The main control module calculates the weighted average of the voltage values ​​of all battery packs and uses this weighted average as the reference value for the dynamic optimal bus voltage. The formula is as follows:

[0080] ;

[0081] in, Represented as the dynamic optimal bus voltage reference value; V i W represents the voltage value of the i-th battery pack. i Let represent the dynamic weighting factor corresponding to the i-th battery pack; n represents the total number of battery packs.

[0082] For example: The main control module calculates the weighted average of the voltages of all battery packs as the reference value for the dynamic optimal bus voltage. The numerator is: (3.3 × 0.93) + (3.1 × 0.9) + (3.2 × 0.925) = 8.819; the denominator is: 0.93 + 0.9 + 0.925 = 2.755; thus, V is obtained. ref =8.819÷2.755≈3.2V;

[0083] S230, the main control module controls the main converter, adjusts the phase shift angle of the internal switching transistors of the main converter, and adjusts the common DC bus voltage to the dynamic optimal bus voltage reference value.

[0084] S300: Based on the dynamic optimal bus voltage reference value and the status of each battery pack, the main control module determines when inter-pack energy transfer is required and issues an energy transfer command to the relevant slave control module; it analyzes the expected efficiency of the direct energy transfer path between the source battery pack and the target battery pack and the relay energy transfer path through the relay battery pack; it analyzes the expected efficiency, selects the path with higher expected efficiency as the final energy transfer scheme, and issues it to the relevant slave control module.

[0085] Specifically, step S300 includes:

[0086] S310 The main control module calculates the absolute value of the deviation between the voltage value of each battery pack and the dynamic optimal bus voltage reference value. When the absolute value of the deviation exceeds the preset voltage deviation threshold, it is determined that inter-pack energy transfer needs to be performed.

[0087] Furthermore, the determination that inter-group energy transfer needs to be performed includes:

[0088] Calculate the terminal voltage V of each battery pack. i With V ref Voltage deviation ΔV i =|V i -V ref |;

[0089] If the voltage deviation of at least one group of batteries exceeds the preset voltage deviation threshold, or if the state of charge difference between at least two groups of batteries exceeds the preset state of charge deviation threshold, then it is determined that inter-group energy transfer needs to be performed.

[0090] Based on the judgment result, the main control module determines the source battery pack and target battery pack for energy transmission, and issues energy transmission instructions to the corresponding slave control modules of the source battery pack and target battery pack. The energy transmission instructions include the source battery pack number, target battery pack number, relay battery pack number and initial transmission power requirement.

[0091] For example: ΔV1 = |3.3 - 3.2| = 0.1V, which is equal to the voltage deviation threshold; ΔV2 = |3.1 - 3.2| = 0.1V; ΔV3 = |3.2 - 3.2| = 0V; At the same time, the difference in state of charge between groups is calculated: SOC1 - SOC2 = 10%. The preset voltage deviation threshold is 0.05V. If the state of charge deviation threshold is exceeded, it is determined that inter-group energy transfer needs to be performed.

[0092] S320: The main control module determines the target battery pack that needs to be replenished or absorb energy and the corresponding source battery pack, and sends an energy transfer command to the slave control module that manages the target battery pack and the source battery pack.

[0093] S330, the main control module calculates the expected efficiency of the direct energy transfer path from the source battery pack to the target battery pack, using the following formula:

[0094] η direct =η source ×η target ;

[0095] Where, η direct表示 Expected performance of direct energy transfer paths; η source Indicates the real-time operating efficiency of the DC-DC converter corresponding to the source battery pack; η target This indicates the real-time operating efficiency of the DC-DC converter corresponding to the target battery pack;

[0096] For example: if the direct transmission path is from battery pack 1 to battery pack 2, the expected efficiency is 0.96 × 0.95 = 0.912;

[0097] S340. The main control module selects battery packs with a state of charge within a preset normal range from all battery packs as candidate relay battery packs, and calculates the expected efficiency of the relay energy transmission path through the relay battery packs, as shown in the following formula:

[0098] η relay,k =η source ×η k 2 ×η target ;

[0099] Where, η relay,k η represents the expected efficiency of relay transmission via the k-th relay battery pack; k This represents the real-time operating efficiency of the DC-DC converter corresponding to the k-th relay battery pack; k represents the index of the relay battery pack.

[0100] For example: Select battery pack No. 3 with a state of charge in a preset normal range as a candidate relay battery pack, with an expected relay path efficiency of 0.884;

[0101] S350: The main control module compares the expected performance of the direct energy transmission path with the maximum expected performance among all candidate relay transmission paths, and selects the path with higher expected performance as the final energy transmission scheme.

[0102] For example: compare the performance of direct path and relay path, and choose direct transmission path as the final solution;

[0103] S360: The main control module sends the final energy transmission scheme to the slave control modules that manage the source battery pack, target battery pack, and relay battery pack.

[0104] S400: Upon receiving the path decision, the slave control module generates charging and discharging control commands based on the energy transmission scheme, adjusts the phase shift angle of the corresponding DC-DC converter, and completes balanced power transmission.

[0105] Specifically, step S400 includes:

[0106] S410. After receiving the final energy transmission scheme from the main control module, the slave control module generates corresponding charging and discharging control commands based on the path type and power allocation rules in the scheme.

[0107] S420. When the energy transmission scheme is a direct energy transmission path, the slave control module that manages the source battery pack generates a discharge control command, which includes the target discharge power of the source battery pack; the slave control module that manages the target battery pack generates a charging control command, which includes the target charging power of the target battery pack, and the target charging power matches the target discharge power of the source battery pack.

[0108] When the energy transmission scheme is a relay transmission path, the slave control module that manages the source battery pack generates a discharge control command, the slave control module that manages the relay battery pack first generates a charging control command, and then generates a discharge control command after the relay battery pack has completed energy reception, and the slave control module that manages the target battery pack generates a charging control command.

[0109] S430: Each slave control module adjusts the output power of the converter by controlling the phase shift angle according to the generated charge and discharge control command, so that the source battery pack discharges at the target discharge power and the target battery pack charges at the target charging power, thus completing the balanced power transfer between battery packs.

[0110] For example: On the source side, the control module adjusts the phase shift angle of the converter corresponding to battery pack 1, causing battery pack 1 to discharge to the common DC bus at 2kW; on the target side, the control module adjusts the phase shift angle of the converter corresponding to battery pack 2, causing battery pack 2 to charge from the bus at 2kW; after 5 minutes of continuous transmission, the state of charge of battery pack 1 drops to 83% and its voltage drops to 3.25V, while the state of charge of battery pack 2 rises to 77% and its voltage rises to 3.15V, achieving initial balancing. This is only an example and is not a limitation.

[0111] S500: Each slave control module feeds back the actual transmission performance to the main control module. The main control module compares the deviation between the actual transmission performance and the expected performance. When the deviation exceeds the preset threshold, it compensates by correcting the dynamic weighting factor or instructing the slave control module to adjust the phase angle adjustment parameter.

[0112] Specifically, step S500 includes:

[0113] S510: Each slave control module collects data in real time and feeds back the actual transmission performance to the main control module;

[0114] Furthermore, step S510 includes:

[0115] During the power equalization process, each slave control module collects the input and output power of the corresponding bidirectional isolation DC-DC converter in real time and analyzes the actual operating efficiency of the converter, as shown in the following formula:

[0116] ;

[0117] Where, η act,mP represents the actual operating efficiency of the m-th converter, i.e., the actual energy transfer efficiency of the converter; in,m P represents the input power of the m-th converter, i.e., the electrical power received by the converter; out,m This is expressed as the output power of the m-th converter, that is, the electrical power output by the converter;

[0118] Each control module analyzes the overall actual transmission performance based on the transmission path type, using the following formula:

[0119] η act,dir =η act,s ×η act,t ;

[0120] η act,relay =η act,s ×η act,k ×η act,t ;

[0121] Where, η act,dir Represented as the actual transmission efficiency of a direct energy transmission path; η act,s η represents the actual efficiency of the source battery pack converter. act,t η represents the actual efficiency of the target battery pack converter. act,relay This represents the actual transmission efficiency of the relay transmission path; η act,k This represents the actual efficiency of the relay battery pack converter.

[0122] For example, each control module collects the input and output power of the converter to calculate the actual efficiency and overall performance.

[0123] Converter No. 1: Input power 2.05kW, output power 1.96kW, actual efficiency η act,1 =1.96÷2.05≈0.956; Converter No. 2: Input power 1.94kW, output power 1.84kW, actual efficiency η act,2 =1.84÷1.94≈0.948; Actual efficiency η of the direct path act,dir =η act,1 ×η act,2 ≈0.956×0.948≈0.906;

[0124] Each slave control module uploads the calculated overall actual transmission performance to the main control module.

[0125] S520: After receiving the overall actual transmission performance feedback from each slave control module, the main control module retrieves the expected performance of the corresponding path and analyzes the performance deviation, using the following formula:

[0126] ;

[0127] Where Δη represents the relative deviation between the actual transmission performance and the expected performance; η act Represented as the overall actual transmission performance; η exp This represents the expected performance of the corresponding path;

[0128] For example: The main control module retrieves the expected performance η of the direct path. exp =0.912, the relative deviation Δη=|(90.6%-91.2%)÷91.2%|×100%≈0.66%, which is less than the performance deviation threshold;

[0129] S530: When the deviation does not exceed the preset performance deviation threshold, the current transmission status is determined to be normal, no compensation is required, and the existing charging and discharging control command is maintained.

[0130] S540. When the deviation exceeds the preset performance deviation threshold, the main control module initiates a compensation mechanism. The compensation mechanism includes: if the deviation is caused by changes in the health status of the battery pack, the main control module re-corrects the dynamic weighting factors of each battery pack, and based on the corrected dynamic weighting factors, recalculates the dynamic optimal bus voltage reference value and issues a new voltage adjustment command to the main converter; if the deviation is caused by fluctuations in the converter's operating status, the main control module issues a phase shift angle adjustment parameter correction command to the corresponding slave control module, instructing the slave control module to adjust the phase shift angle increment of the converter switching transistors until the deviation drops to within the preset threshold.

[0131] This invention provides another technical solution: a method for equalizing power transmission between battery packs, which selects relay path efficiency;

[0132] Data collected and uploaded from each control module: Battery pack 1 (source-side candidate): V1=3.4V, SOC1=90%, SOH1=0.82, corresponding converter efficiency η1=0.88; Battery pack 2 (target-side candidate): V2=3.0V, SOC2=70%, SOH2=0.78, corresponding converter efficiency η2=0.85; Battery pack 3 (relay candidate): V3=3.2V, SOC3=80%, SOH3=0.92, corresponding converter efficiency η3=0.99; Current voltage of common DC bus = 3.2V;

[0133] Dynamic weighting factor calculation: W1=0.5×0.82+0.5×0.88=0.85; W2=0.5×0.78+0.5×0.85=0.815; W3=0.5×0.92+0.5×0.99=0.955;

[0134] Dynamic optimal bus voltage reference value generation V ref =8.375÷2.615≈3.203V;

[0135] The main control module selects battery pack No. 3, whose state of charge is within a preset normal range, as a candidate relay battery pack, and calculates the expected efficiency of the relay transmission path from battery pack No. 1 to battery pack No. 3 to battery pack No. 2.

[0136] The real-time efficiency of the converter corresponding to battery pack 1 is η1=0.85, the real-time efficiency of the converter corresponding to battery pack 2 is η2=0.83, and the real-time efficiency of the converter corresponding to battery pack 3 is η3=0.98. In addition, there is additional line loss in the direct transmission between battery packs 1 and 2.

[0137] The expected performance of a direct transmission path needs to be factored in by line losses: η direct =(η1×η2)×0.95=(0.88×0.85)×0.95≈0.7055×0.95≈0.7106;

[0138] Expected performance of relay transmission path: η relay,3 =η1×η3 2 ×η2=0.88×0.99×0.99×0.85≈0.88×0.9801×0.85≈0.733;

[0139] The relay transmission path is selected as the final energy transmission scheme; No. 1 generates a discharge command from the control module (source), No. 3 generates a charge-then-discharge command from the control module (relay), and No. 2 generates a charging command from the control module (target).

[0140] This invention provides another technical solution: a method for equalizing power transmission between battery packs, which includes activating a compensation mechanism;

[0141] Battery pack #1 was identified as the source battery pack, with V1=3.3V, SOC1=85%, and η1=0.96. Battery pack #2 was identified as the target battery pack, with V2=3.1V, SOC2=75%, and η2=0.95. ref =3.2V, direct transmission path selected, expected performance η exp =0.96×0.95=0.912, initial transmission power 2kW;

[0142] Actual performance data: Converter 1: Input 2.05kW, Output 1.96kW, η act,1 =1.96÷2.05≈0.956; Converter No. 2: Due to temperature rise, the input is 1.94kW, but the output is only 1.75kW, η act,2 =1.75÷1.94≈0.902; Actual efficiency η act,dir =0.956×0.902≈0.862, uploaded to the main control module;

[0143] The relative deviation Δη = |(86.2%-91.2%)÷91.2%|×100%≈5.48%>5% performance deviation threshold, indicating that a compensation mechanism needs to be activated;

[0144] The main control module analyzes the cause of the deviation: the efficiency of converter No. 2 has decreased, which is not due to changes in the battery health status. Therefore, it chooses to adjust the phase shift angle parameter to compensate: it sends a command to slave control module No. 2 to correct the phase shift angle of the converter from 16° to 15°, thereby reducing the phase shift angle to improve the output power.

[0145] After executing the command from the control module, No. 2 re-collected data: input 1.94kW, output 1.83kW, η act,2 =1.83÷1.94≈0.943;

[0146] Actual efficiency η act,dir =0.956×0.943≈0.902, Δη=|(90.2%-91.2%)÷91.2%|×100%≈1.1%<5% efficiency deviation threshold, compensation completed.

[0147] This invention provides another technical solution: an inter-pack equalization power transmission system for battery packs, which includes: an optimization and decision-making module, a power regulation module, a power execution module, a data acquisition module, and an efficiency monitoring module.

[0148] The data acquisition module collects real-time data on battery pack status, converter operation, and bus voltage, and transmits this data to the optimization and decision-making module. The optimization and decision-making module receives all uploaded data, executes global calculations and optimization algorithms, and generates system-level control objectives and strategies. The power regulation module receives the strategy schemes from the optimization and decision-making module and converts them into specific, executable hardware-level control signals to drive the power converter to perform energy transfer. The power execution module completes bidirectional and isolated energy transfer based on the received control signals. The performance monitoring module monitors the actual energy transfer effect in real-time and compares it with the expected target; when a deviation occurs, it automatically triggers a compensation mechanism.

[0149] The optimization and decision-making module includes a weight allocation module, a reference value generation module, and a path performance analysis module. The weight allocation module assigns dynamic weight factors to the battery packs based on their health status and the real-time operating efficiency of their corresponding DC-DC converters. The reference value generation module obtains the dynamically optimal bus voltage reference value based on the voltage of all battery packs and their dynamic weights. The path performance analysis module analyzes the expected performance of direct and relay transmission paths and selects the path with the highest performance as the final solution.

[0150] The power regulation module includes an instruction parsing module and a control signal generation module. The instruction parsing module parses the path type, power level, source battery pack, target battery pack, and relay battery pack numbering information in the energy transmission scheme. The control signal generation module generates specific pulse width modulation or phase shift control signals according to the instructions and sends them to the corresponding DC-DC converter.

[0151] The power execution module includes a bidirectional isolation converter corresponding to the battery pack, which achieves bidirectional energy transmission and electrical isolation through phase shift control of the switching transistor.

[0152] The performance monitoring module includes an actual performance analysis module, a deviation analysis module, and a compensation execution module. The actual performance analysis module calculates the efficiency of each converter and the actual performance of the overall transmission path in real time. The deviation analysis module calculates the relative deviation and determines whether compensation is needed. The compensation execution module selects to compensate based on the battery pack or converter with deviation, either by correcting the global weighting factor or by adjusting the local phase shift angle parameter.

[0153] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for equalizing power transfer between battery packs, characterized in that: The method includes: S100: Each slave control module collects the voltage information, state of charge information, health status information of the corresponding battery pack and the operating efficiency data of each bidirectional isolated DC-DC converter in real time, and uploads them to the main control module. S200: The main control module assigns a dynamic weighting factor to each battery pack based on the health status of each battery pack and the operating efficiency of the corresponding DC converter; it generates a dynamic optimal bus voltage reference value based on the voltage values ​​of all battery packs and the corresponding dynamic weighting factors, and controls the main converter to adjust the common DC bus voltage to the optimal bus voltage reference value. S300: Based on the dynamic optimal bus voltage reference value and the status of each battery pack, the main control module determines when inter-pack energy transfer is required and issues an energy transfer command to the relevant slave control module; it analyzes the expected efficiency of the direct energy transfer path between the source battery pack and the target battery pack and the relay energy transfer path through the relay battery pack; it analyzes the expected efficiency, selects the path with higher expected efficiency as the final energy transfer scheme, and issues it to the relevant slave control module. S400: Upon receiving the path decision, the slave control module generates a charging and discharging control command based on the energy transmission scheme, adjusts the phase shift angle of the corresponding DC-DC converter, and completes the balanced power transmission. S500: Each slave control module feeds back the actual transmission performance to the main control module. The main control module compares the deviation between the actual transmission performance and the expected performance. When the deviation exceeds the preset threshold, it compensates by correcting the dynamic weighting factor or instructing the slave control module to adjust the phase angle adjustment parameter.

2. The method for inter-pack power equalization transmission of a battery pack according to claim 1, characterized in that: Step S200 includes: S210. The main control module assigns a dynamic weighting factor to each battery pack. The weighting factor is determined by the health status of the battery pack and the real-time operating efficiency of its corresponding DC-DC converter, as shown in the following formula: W i =f(SOH i ,η i ); Among them, W i SOH represents the dynamic weighting factor corresponding to the i-th battery pack; i represents the index of the battery pack; i This represents the health status of the i-th battery pack; η i Let f represent the real-time operating efficiency of the DC-DC converter corresponding to the i-th battery pack; f represents the positive correlation function between the health status of the battery pack and the real-time operating efficiency of the corresponding DC-DC converter. S220. The main control module calculates the weighted average of the voltage values ​​of all battery packs, and uses the weighted average as the reference value of the dynamic optimal bus voltage, as shown in the following formula: ； in, Represented as the dynamic optimal bus voltage reference value; V i W represents the voltage value of the i-th battery pack. i Let represent the dynamic weighting factor corresponding to the i-th battery pack; n represents the total number of battery packs. S230. The main control module controls the main converter, adjusts the phase shift angle of the internal switching transistors of the main converter, and adjusts the common DC bus voltage to the dynamic optimal bus voltage reference value.

3. The method for inter-pack power equalization transmission of a battery pack according to claim 1, characterized in that: Step S300 includes: S310. The main control module calculates the absolute value of the deviation between the voltage value of each battery pack and the reference value of the dynamic optimal bus voltage. When the absolute value of the deviation exceeds the preset voltage deviation threshold, it is determined that inter-pack energy transfer needs to be performed. S320. The main control module determines the target battery pack that needs to be replenished or absorb energy and the corresponding source battery pack, and sends an energy transfer command to the slave control module that manages the target battery pack and the source battery pack. S330, The main control module calculates the expected efficiency of the direct energy transfer path from the source battery pack to the target battery pack; S340. The main control module selects battery packs with a state of charge in a preset normal range from all battery packs as candidate relay battery packs, and calculates the expected efficiency of relaying energy through the relay battery packs. S350. The main control module compares the expected efficiency of the direct energy transmission path with the maximum expected efficiency among all candidate relay transmission paths, and selects the path with higher expected efficiency as the final energy transmission scheme. S360, the main control module sends the final determined energy transmission scheme to the slave control modules that manage the source battery pack, target battery pack and relay battery pack.

4. The method for inter-pack power equalization transmission of a battery pack according to claim 3, characterized in that: The determination that inter-group energy transfer needs to be performed includes: Calculate the terminal voltage V of each battery pack. i With V ref Voltage deviation ΔV i =|V i -V ref |; If the voltage deviation of at least one group of batteries exceeds the preset voltage deviation threshold, or if the state of charge difference between at least two groups of batteries exceeds the preset state of charge deviation threshold, then it is determined that inter-group energy transfer needs to be performed. Based on the determination result, the main control module determines the source battery pack and target battery pack for energy transmission, and issues energy transmission instructions to the corresponding slave control modules of the source battery pack and target battery pack. The energy transmission instructions include the source battery pack number, the target battery pack number, the relay battery pack number, and the initial transmission power requirement.

5. The method for inter-pack power equalization transmission of a battery pack according to claim 1, characterized in that: Step S400 includes: S410. After receiving the final energy transmission scheme from the main control module, the slave control module generates corresponding charging and discharging control commands based on the path type and power allocation rules in the scheme. S420. When the energy transmission scheme is a direct energy transmission path, the slave control module managing the source battery pack generates a discharge control command, which includes the target discharge power of the source battery pack; the slave control module managing the target battery pack generates a charging control command, which includes the target charging power of the target battery pack, and the target charging power matches the target discharge power of the source battery pack. When the energy transmission scheme is a relay transmission path, the slave control module that manages the source battery pack generates a discharge control command, the slave control module that manages the relay battery pack first generates a charging control command, and then generates a discharge control command after the relay battery pack has completed energy reception, and the slave control module that manages the target battery pack generates a charging control command. S430: Each slave control module adjusts the output power of the converter by controlling the phase shift angle according to the generated charge and discharge control command, so that the source battery pack discharges at the target discharge power and the target battery pack charges at the target charging power, thus completing the balanced power transfer between battery packs.

6. The method for inter-pack power equalization transmission of a battery pack according to claim 1, characterized in that: Step S500 includes: S510: Each slave control module collects data in real time and feeds back the actual transmission performance to the main control module; S520: After receiving the overall actual transmission performance feedback from each slave control module, the main control module retrieves the expected performance of the corresponding path and analyzes the performance deviation, using the following formula: ； Where Δη represents the relative deviation between the actual transmission performance and the expected performance; η act Represented as the overall actual transmission performance; η exp This represents the expected performance of the corresponding path; S530: When the deviation does not exceed the preset performance deviation threshold, the current transmission status is determined to be normal, no compensation is required, and the existing charging and discharging control command is maintained. S540. When the deviation exceeds the preset performance deviation threshold, the main control module initiates a compensation mechanism. The compensation mechanism includes: if the deviation is caused by changes in the health status of the battery pack, the main control module re-corrects the dynamic weighting factors of each battery pack, and based on the corrected dynamic weighting factors, recalculates the dynamic optimal bus voltage reference value and issues a new voltage adjustment command to the main converter; if the deviation is caused by fluctuations in the converter's operating status, the main control module issues a phase shift angle adjustment parameter correction command to the corresponding slave control module, instructing the slave control module to adjust the phase shift angle increment of the converter switching transistor until the deviation drops to within the preset threshold.

7. The method for inter-pack power equalization transmission of a battery pack according to claim 6, characterized in that: Step S510 includes: During the power equalization process, each slave control module collects the input and output power of the corresponding bidirectional isolation DC-DC converter in real time and analyzes the actual operating efficiency of the converter, as shown in the following formula: ； Where, η act,m P represents the actual operating efficiency of the m-th converter, i.e., the actual energy transfer efficiency of the converter; in,m P represents the input power of the m-th converter, i.e., the electrical power received by the converter; out,m This is expressed as the output power of the m-th converter, that is, the electrical power output by the converter; Each slave control module analyzes the overall actual transmission performance based on the transmission path type, and then uploads the calculated overall actual transmission performance to the main control module.

8. A battery pack inter-pack equalization power transmission system, characterized in that: The system includes: an optimization and decision-making module, a power regulation module, a power execution module, a data acquisition module, and a performance monitoring module; The data acquisition module is used to collect battery pack status, converter operating data, and bus voltage in real time, and transmit the data to the optimization and decision-making module. The optimization and decision-making module receives all uploaded data, executes global calculation and optimization algorithms, and generates system-level control objectives and strategies. The optimization and decision-making module includes a weight allocation module, a reference value generation module, and a path efficiency analysis module. The weight allocation module assigns dynamic weight factors to the battery packs based on their health status and the real-time operating efficiency of their corresponding DC-DC converters. The reference value generation module obtains the dynamically optimal bus voltage reference value based on the voltage of all battery packs and the dynamic weights. The path efficiency analysis module analyzes the expected efficiency of direct and relay transmission paths and selects the path with the highest efficiency as the final solution. The power regulation module receives the strategy schemes issued by the optimization and decision-making module, converts them into control signals, and drives the power converter to perform energy transmission. The power execution module completes bidirectional and isolated energy transmission based on the received control signals. The efficiency monitoring module monitors the actual effect of energy transmission in real time and compares it with the expected target. When a deviation occurs, it automatically triggers a compensation mechanism.

9. The inter-pack equalization power transmission system for a battery pack according to claim 8, characterized in that: The power regulation module includes an instruction parsing module and a control signal generation module. The instruction parsing module parses the path type, power magnitude, source battery pack, target battery pack, and relay battery pack numbering information in the energy transmission scheme. The control signal generation module generates specific pulse width modulation or phase shift control signals according to the instructions and sends them to the corresponding DC-DC converter. The power execution module includes a bidirectional isolation converter corresponding to the battery pack, which achieves bidirectional energy transmission and electrical isolation through phase shift control of the switching transistor.

10. The inter-pack equalization power transmission system for a battery pack according to claim 8, characterized in that: The performance monitoring module includes an actual performance analysis module, a deviation analysis module, and a compensation execution module. The actual performance analysis module calculates the efficiency of each converter and the actual performance of the overall transmission path in real time. The deviation analysis module calculates the relative deviation and determines whether compensation is needed. The compensation execution module selects to compensate based on the battery pack or converter with the deviation, either by correcting the global weighting factor or by adjusting the local phase shift angle parameter.

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