A control method and system for a parallel battery system

Abstract

The application discloses a control method and system for a parallel battery system, and mainly relates to the technical field of parallel battery systems, and aims to solve the problem that the voltage regulation of the existing parallel battery system is not accurate. The method comprises the following steps: acquiring voltage information and state-of-charge information of each battery subsystem of the parallel battery system through a battery system information collector; transmitting the state-of-charge information to a controller to determine the grid-connected power-on rules of each battery subsystem through the controller; transmitting the voltage information to the controller to determine the corresponding grid-connected voltage difference of each battery subsystem through the controller, and then screening voltage-unbalanced battery subsystems from the battery subsystems; calculating a voltage deviation rate through the controller based on the voltage information of the voltage-unbalanced battery subsystems; and determining the power calibration amount of the charging and discharging equipment in the voltage-unbalanced battery subsystems according to the voltage deviation rate and the grid-connected voltage difference. The application realizes the accuracy of voltage balancing through the above method.

Description

Technical Field

[0001] This application relates to the field of parallel battery system technology, and in particular to a control method and system for parallel battery systems. Background Technology

[0002] Currently, the weight of high-power battery packs significantly limits the space available for battery transportation and installation. Therefore, small-power battery modules can be combined to obtain the required high-power battery modules, thus solving transportation problems and meeting diverse market demands.

[0003] Typically, in a parallel battery system, if a battery subsystem experiences voltage imbalance, the internal current circulation of that subsystem can damage the entire battery system. To restore balance, existing methods primarily involve charging and discharging the subsystem with the voltage imbalance.

[0004] However, in a parallel battery system, abruptly charging or discharging a battery subsystem with an unbalanced voltage can easily lead to overcharging or over-discharging of that subsystem. If the battery system is in operation, current flows in the battery circuit during charging or discharging, and cutting off or closing the corresponding battery subsystem relays may cause the relays to stick or become damaged. Furthermore, due to the battery's internal resistance and varying loads, the terminal voltage of this battery subsystem will be lower than its open-circuit voltage during discharge and higher than its open-circuit voltage during charging. This results in inaccurate voltage regulation during charging and discharging, leaving the battery subsystem in a voltage-unbalanced state within the battery system. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a control method and system for parallel battery systems to solve the above-mentioned technical problems.

[0006] In a first aspect, this application provides a control method for a parallel battery system. The parallel battery system includes: a battery system information collector, battery subsystems, a controller, and power equipment. The method includes: before the vehicle is powered on at high voltage, acquiring voltage information and state of charge (SOC) information of each battery subsystem in the parallel battery system through the battery system information collector; transmitting the SOC information to the controller to determine the grid connection power-on rules for each battery subsystem; transmitting voltage information to the controller to determine the grid connection voltage difference corresponding to each battery subsystem, and then selecting voltage-unbalanced battery subsystems from among the battery subsystems; calculating the voltage deviation rate through the controller based on the voltage information of the voltage-unbalanced battery subsystems; determining the power calibration amount of the charging and discharging equipment in the voltage-unbalanced battery subsystem according to the voltage deviation rate and the grid connection voltage difference, and then adjusting the power of the charging and discharging equipment to complete the grid connection power-on of the voltage-unbalanced battery subsystem.

[0007] Furthermore, the controller determines the grid connection rules for each battery subsystem, specifically including: detecting whether the state of charge (SOC) information is greater than a preset system SOC threshold; when the SOC information is greater than the preset system SOC threshold, the battery subsystem is determined to be a fully charged subsystem, and the grid connection rule for the fully charged subsystem is to connect to the grid sequentially from high to low voltage; when the SOC information is less than or equal to the preset system SOC threshold, the battery subsystem is determined to be a depleted subsystem, and the grid connection rule for the depleted subsystem is to connect to the grid sequentially from low to high voltage.

[0008] Furthermore, the controller determines the grid-connected voltage difference corresponding to each battery subsystem, and then filters out the battery subsystems with unbalanced voltage from each battery subsystem. Specifically, the controller sorts the battery subsystems in ascending order of voltage value according to the voltage information of each battery subsystem to obtain a first voltage value sequence of battery subsystems; determines the difference between adjacent voltage values ​​in the first voltage value sequence as the grid-connected voltage difference; determines whether the grid-connected voltage difference is greater than a preset voltage difference threshold; when it is greater than the preset voltage difference threshold, determines the battery subsystem corresponding to the minimum value between two adjacent voltage values ​​corresponding to the grid-connected voltage difference as the battery subsystem with unbalanced voltage.

[0009] Furthermore, the controller determines the grid-connected voltage difference corresponding to each battery subsystem, and then filters out the battery subsystems with unbalanced voltage from each battery subsystem. Specifically, the controller sorts the battery subsystems in descending order of voltage value based on the voltage information of each battery subsystem to obtain a second voltage value sequence of battery subsystems; determines the difference between adjacent voltage values ​​in the second voltage value sequence as the grid-connected voltage difference; determines whether the grid-connected voltage difference is greater than a preset voltage difference threshold; when it is greater than the preset voltage difference threshold, determines the battery subsystem corresponding to the maximum value between two adjacent voltage values ​​corresponding to the grid-connected voltage difference as the battery subsystem with unbalanced voltage.

[0010] Furthermore, based on the voltage information of the voltage-unbalanced battery subsystem, the controller calculates the voltage deviation rate, specifically including: the controller determines the grid-connected voltage difference corresponding to the voltage information of the voltage-unbalanced battery subsystem; then determines the voltage value of the non-voltage-unbalanced battery subsystem for calculating the grid-connected voltage difference as the target voltage; and uses the grid-connected voltage difference divided by the target voltage to obtain the voltage deviation rate of the voltage-unbalanced battery subsystem.

[0011] Furthermore, based on the voltage deviation rate and the grid voltage difference, the power calibration amount of the charging and discharging equipment in the voltage imbalance battery subsystem is determined. Specifically, this includes: the controller calculates the balancing power based on the grid voltage difference as the initial balancing power; based on the voltage deviation rate, the calibration amount used for balancing power calibration is calculated in real time, and the initial balancing power is summed with the calibration amount to obtain the power calibration amount; and the power equipment performs charging or discharging operations on the voltage imbalance battery in the voltage imbalance battery subsystem according to the power calibration amount.

[0012] Furthermore, adjusting the power of the charging and discharging equipment to complete the grid connection of the voltage imbalance battery subsystem specifically includes: the controller generating a power command for voltage balance control based on the power calibration amount; so that the power equipment responds and operates according to the power command to complete the grid connection of the voltage imbalance battery subsystem.

[0013] Secondly, this application provides a control system for a parallel battery system. The system includes: an acquisition module, used to acquire voltage information and state of charge information of each battery subsystem in the parallel battery system through a battery system information collector before the vehicle is powered on; a determination module, used to transmit the state of charge information to a controller so that the controller can determine the grid connection power-on rules of each battery subsystem; a screening module, used to transmit voltage information to the controller so that the controller can determine the grid connection voltage difference corresponding to each battery subsystem, and then screen out the voltage-unbalanced battery subsystems from the battery subsystems; and a power-on module, used to calculate the voltage deviation rate through the controller based on the voltage information of the voltage-unbalanced battery subsystems; and determine the power calibration amount of the charging and discharging equipment in the voltage-unbalanced battery subsystem according to the voltage deviation rate and the grid connection voltage difference, and then adjust the power of the charging and discharging equipment to complete the grid connection power-on of the voltage-unbalanced battery subsystem.

[0014] Those skilled in the art will understand that the present invention has at least the following beneficial effects:

[0015] This application proposes a control method and system for parallel battery systems. This method prioritizes determining whether the battery system is in a state of high or low charge before deciding on charging or discharging, thereby reducing the risk of overcharging or over-discharging. During the grid connection process, the method utilizes the battery's state of charge distribution to regulate the charging or discharging of voltage-unbalanced battery subsystems before grid connection, effectively avoiding voltage imbalance during battery operation and preventing relay damage and sticking failures that can occur with closing and opening relays. Furthermore, by using voltage deviation rate to control the power output of the power equipment, the method significantly reduces the impact of battery internal resistance, thus ensuring accurate voltage balance. Attached Figure Description

[0016] The following description refers to some embodiments of this disclosure, in which:

[0017] Figure 1 This is a schematic diagram of the internal structure of a parallel battery system provided in an embodiment of this application.

[0018] Figure 2 This is a flowchart of a control method for a parallel battery system provided in an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the internal structure of a control system for a parallel battery system provided in an embodiment of this application. Detailed Implementation

[0020] Those skilled in the art should understand that the embodiments described below are merely preferred embodiments of this disclosure and do not imply that this disclosure can only be implemented through these preferred embodiments. These preferred embodiments are merely used to explain the technical principles of this disclosure and are not intended to limit the scope of protection of this disclosure. Based on the preferred embodiments provided by this disclosure, all other embodiments obtained by those skilled in the art without creative effort should still fall within the scope of protection of this disclosure.

[0021] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0022] The technical solutions proposed in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0023] This application provides an embodiment for a parallel battery system, such as... Figure 1 As shown, the parallel battery system provided in this application embodiment includes: a battery system information collector 10, battery subsystems 11, a controller 20, and a power device 30; the battery system information collector 10 is configured to collect information such as voltage and state of charge of multiple battery subsystems 11; the controller 20 is configured to receive the battery information collected by the battery system information collector 10, so as to control the power-on sequence, determine the voltage imbalance subsystem, and generate a calibrated power command for voltage balance control; the power device 30 is configured to respond to the operation according to the calibrated power command generated and output by the controller 20.

[0024] This application provides a control method for a parallel battery system, such as... Figure 2As shown in the embodiments of this application, the method mainly includes the following steps:

[0025] Step 210: Before the vehicle is powered on, the voltage and state of charge information of each battery subsystem in the parallel battery system are obtained through the battery system information collector.

[0026] Step 220: Transmit the state of charge information to the controller so that the controller can determine the grid connection rules for each battery subsystem.

[0027] As an example, the controller detects whether the state of charge (SOC) information is greater than a preset system SOC threshold. When the SOC information is greater than the preset system SOC threshold, the battery subsystem is determined to be a fully charged subsystem, and the grid connection rule for the fully charged subsystem is to connect to the grid sequentially from high to low voltage. When the SOC information is less than or equal to the preset system SOC threshold, the battery subsystem is determined to be a depleted subsystem, and the grid connection rule for the depleted subsystem is to connect to the grid sequentially from low to high voltage.

[0028] Step 230: Transmit voltage information to the controller so that the controller can determine the grid voltage difference corresponding to each battery subsystem and then select the battery subsystem with voltage imbalance from each battery subsystem.

[0029] As an example, after determining that the battery subsystem is in a depleted state, the controller sorts the battery subsystems by voltage value from low to high according to the voltage information of each battery subsystem to obtain the first voltage value sequence of the battery subsystem; determines that the difference between adjacent voltage values ​​in the first voltage value sequence is the grid voltage difference; determines whether the grid voltage difference is greater than a preset voltage difference threshold; when it is greater than the preset voltage difference threshold, determines that the battery subsystem corresponding to the minimum value between two adjacent voltage values ​​corresponding to the grid voltage difference is the voltage unbalanced battery subsystem.

[0030] As an example 2, after determining that the battery subsystem is a fully charged subsystem, the controller sorts the battery subsystems according to their voltage information in descending order of voltage value to obtain a second voltage value sequence for the battery subsystems; the difference between adjacent voltage values ​​in the second voltage value sequence is determined as the grid-connected voltage difference; it is then determined whether the grid-connected voltage difference is greater than a preset voltage difference threshold; when it is greater than the preset voltage difference threshold, the battery subsystem corresponding to the maximum value between two adjacent voltage values ​​corresponding to the grid-connected voltage difference is determined to be a voltage-unbalanced battery subsystem.

[0031] Step 240: Based on the voltage information of the voltage imbalance battery subsystem, calculate the voltage deviation rate through the controller; determine the power calibration amount of the charging and discharging equipment in the voltage imbalance battery subsystem according to the voltage deviation rate and the grid voltage difference, and then adjust the power of the charging and discharging equipment to complete the grid connection of the voltage imbalance battery subsystem.

[0032] As an example, based on the voltage information of the voltage-unbalanced battery subsystem, the voltage deviation rate is calculated by the controller. Specifically, the controller determines the grid voltage difference corresponding to the voltage information of the voltage-unbalanced battery subsystem; then determines the voltage value of the non-voltage-unbalanced battery subsystem for calculating the grid voltage difference as the target voltage; and uses the grid voltage difference divided by the target voltage to obtain the voltage deviation rate of the voltage-unbalanced battery subsystem.

[0033] As an example, the power calibration amount of the charging and discharging equipment in the voltage imbalance battery subsystem is determined based on the voltage deviation rate and the grid voltage difference. Specifically, the controller calculates the balancing power based on the grid voltage difference as the initial balancing power; the calibration amount used for balancing power calibration is calculated in real time based on the voltage deviation rate, and the initial balancing power is summed with the calibration amount to obtain the power calibration amount; the power equipment then charges or discharges the voltage imbalance battery in the voltage imbalance battery subsystem according to the power calibration amount.

[0034] Specifically, the balanced power is calculated based on the grid voltage difference as follows: The balanced power is calculated using the formula: P=β*ΔU; where β represents the pre-set power coefficient and ΔU represents the grid voltage difference.

[0035] Specifically, the calibration amount used for real-time balanced power calibration is calculated based on the voltage offset rate as follows: the voltage offset rate is calculated using the formula: ΔP=α*γ, where γ represents the preset voltage offset rate and α represents the voltage offset rate.

[0036] As an example, adjusting the power of the charging and discharging equipment to complete the grid connection of the voltage-unbalanced battery subsystem can be achieved by: the controller generating a power command for voltage balance control based on the power calibration amount; and the power equipment responding to the power command to complete the grid connection of the voltage-unbalanced battery subsystem.

[0037] besides, Figure 3 This application provides a control system for a parallel battery system. For example... Figure 3 As shown in the embodiments of this application, the system mainly includes:

[0038] The acquisition module 310 is used to acquire the voltage information and state of charge information of each battery subsystem in the parallel battery system through the battery system information collector before the vehicle is powered on with high voltage.

[0039] The determination module 320 is used to transmit state of charge information to the controller so that the controller can determine the grid connection rules of each battery subsystem.

[0040] The screening module 330 is used to transmit voltage information to the controller so that the controller can determine the grid voltage difference corresponding to each battery subsystem and then screen out the battery subsystems with unbalanced voltage from each battery subsystem.

[0041] The power-on module 340 is used to calculate the voltage deviation rate based on the voltage information of the voltage imbalance battery subsystem through the controller; and to determine the power calibration amount of the charging and discharging equipment in the voltage imbalance battery subsystem according to the voltage deviation rate and the grid voltage difference, thereby adjusting the power of the charging and discharging equipment to complete the grid connection of the voltage imbalance battery subsystem.

[0042] The technical solutions of this disclosure have been described in conjunction with the preceding embodiments. However, it will be readily understood by those skilled in the art that the scope of protection of this disclosure is not limited to these specific embodiments. Without departing from the technical principles of this disclosure, those skilled in the art can disassemble and combine the technical solutions in the above embodiments, and can also make equivalent changes or substitutions to the relevant technical features. Any changes, equivalent substitutions, improvements, etc., made within the technical concept and / or technical principles of this disclosure will fall within the scope of protection of this disclosure.

Claims

1. A control method for a parallel battery system, characterized in that, The parallel battery system includes: a battery system information collector, a battery subsystem, a controller, and a power unit; the method includes: Before the vehicle is powered on, the voltage and state of charge information of each battery subsystem in the parallel battery system are obtained through the battery system information collector. Transmit state of charge information to the controller so that the controller can determine the grid connection rules for each battery subsystem; The voltage information is transmitted to the controller so that the controller can determine the grid voltage difference corresponding to each battery subsystem and then select the battery subsystem with voltage imbalance from each battery subsystem. Based on the voltage information of the voltage imbalance battery subsystem, the voltage deviation rate is calculated by the controller; based on the voltage deviation rate and the grid voltage difference, the power calibration amount of the power equipment in the voltage imbalance battery subsystem is determined, and then the power of the power equipment is adjusted to complete the grid connection of the voltage imbalance battery subsystem. Based on the voltage information of the voltage-unbalanced battery subsystem, the voltage deviation rate is calculated by the controller, specifically including: The controller determines the grid-connected voltage difference corresponding to the voltage information of the voltage-unbalanced battery subsystem; then determines the target voltage value for the non-voltage-unbalanced battery subsystem used to calculate the grid-connected voltage difference. The voltage offset rate of the voltage-unbalanced battery subsystem is obtained by dividing the grid voltage difference by the target voltage.

2. The control method for a parallel battery system according to claim 1, characterized in that, The controller determines the grid connection rules for each battery subsystem, specifically including: The controller detects whether the state of charge information is greater than the preset system state of charge threshold. When the state of charge information is greater than the preset system state of charge threshold, the battery subsystem is determined to be a state-rich subsystem. The grid connection rule for determining the state-rich subsystem is to connect to the grid sequentially from high voltage to low voltage. When the state of charge information is less than or equal to the preset system state of charge threshold, the battery subsystem is determined to be a depleted state subsystem. The grid connection rule for the depleted state subsystem is to connect to the grid sequentially from low to high voltage.

3. The control method for a parallel battery system according to claim 2, characterized in that, The controller determines the grid-connected voltage difference for each battery subsystem, and then filters out battery subsystems with voltage imbalance from among them. Specifically, this includes: After determining that the battery subsystem is in a state of depletion... The controller sorts the battery subsystems by voltage information from low to high to obtain the first voltage value sequence of the battery subsystems. The difference between adjacent voltage values ​​in the first voltage value sequence is defined as the grid voltage difference. Determine whether the grid-connected voltage difference is greater than a preset voltage difference threshold; if it is greater than the preset voltage difference threshold, determine the battery subsystem corresponding to the minimum value between two adjacent voltage values ​​corresponding to the grid-connected voltage difference as the voltage unbalanced battery subsystem.

4. The control method for a parallel battery system according to claim 2, characterized in that, The controller determines the grid-connected voltage difference for each battery subsystem, and then filters out battery subsystems with voltage imbalance from among them. Specifically, this also includes: After determining that the battery subsystem is a state-rich subsystem The controller sorts the battery subsystems by voltage information from high to low to obtain the second voltage value sequence of the battery subsystems. The difference between adjacent voltage values ​​in the second voltage value sequence is defined as the grid voltage difference. Determine whether the grid-connected voltage difference is greater than a preset voltage difference threshold; if it is greater than the preset voltage difference threshold, determine the battery subsystem corresponding to the maximum value between two adjacent voltage values ​​corresponding to the grid-connected voltage difference as the voltage unbalanced battery subsystem.

5. The control method for a parallel battery system according to claim 1, characterized in that, Based on the voltage offset rate and grid voltage difference, the power calibration amount of the power equipment in the voltage imbalance battery subsystem is determined, specifically including: The controller calculates the balanced power based on the grid voltage difference, which is used as the initial amount of balanced power. Based on the voltage offset rate, the calibration amount used for balancing power calibration is calculated in real time. The initial balancing power amount is summed with the calibration amount to obtain the power calibration amount. Through the power equipment, the voltage unbalanced battery in the voltage unbalanced battery subsystem is charged or discharged according to the power calibration amount.

6. The control method for a parallel battery system according to claim 1, characterized in that, Adjusting the power of the power equipment to complete the grid connection of the voltage-unbalanced battery subsystem, specifically including: The controller generates a power command for voltage balance control based on the power calibration amount, so that the power equipment responds to the power command and completes the grid connection of the voltage imbalance battery subsystem.

7. A control system for a parallel battery system, characterized in that, The system includes: The acquisition module is used to acquire the voltage and state of charge information of each battery subsystem in the parallel battery system through the battery system information collector before the vehicle is powered on with high voltage. The determination module is used to transmit state of charge information to the controller so that the controller can determine the grid connection power-on rules for each battery subsystem; The screening module is used to transmit voltage information to the controller so that the controller can determine the grid-connected voltage difference corresponding to each battery subsystem and then screen out the battery subsystems with voltage imbalance from each battery subsystem. The power-on module is used to calculate the voltage deviation rate based on the voltage information of the voltage imbalance battery subsystem through the controller; and to determine the power calibration amount of the power equipment in the voltage imbalance battery subsystem according to the voltage deviation rate and the grid voltage difference, thereby adjusting the power of the power equipment and completing the grid connection of the voltage imbalance battery subsystem. Based on the voltage information of the voltage-unbalanced battery subsystem, the voltage deviation rate is calculated by the controller, specifically including: The controller determines the grid-connected voltage difference corresponding to the voltage information of the voltage-unbalanced battery subsystem; then determines the target voltage value for the non-voltage-unbalanced battery subsystem used to calculate the grid-connected voltage difference. The voltage offset rate of the voltage-unbalanced battery subsystem is obtained by dividing the grid voltage difference by the target voltage.

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