Multi-battery-pack parallel charging control method, device, system and aircraft

Abstract

This invention provides a method, apparatus, system, and aircraft for controlling parallel charging of multiple battery packs, relating to the field of battery management technology. In the hardware access stage, based on the initial voltage sorting results, the invention dynamically calculates and sets a pre-charge current threshold by real-time monitoring of the voltage difference and the real-time internal resistance of the battery packs. This precisely limits the circulating current instantaneously generated by the contactor in the closed charging circuit to a safe range, achieving the function of the voltage equalization module in suppressing inrush current and voltage balancing without additional hardware. In the software management stage, the total SOC value is calculated based on at least one of the health status and rated capacity of each battery pack. This ensures the feedback accuracy of the total SOC value even without a voltage equalization module, and dynamically distributes the current according to the health status of each battery pack, achieving the balancing effect of the voltage equalization module at the logical level. Therefore, this invention achieves safe and efficient parallel charging of multiple battery packs without using a voltage equalization module.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a method, apparatus, system, and aircraft for controlling parallel charging of multiple battery packs. Background Technology

[0002] As a novel type of air transportation, eVTOL (Electric Vertical Takeoff and Landing) aircraft require battery system design that prioritizes lightweight design and extreme reliability. Given the high weight sensitivity of eVTOL aircraft, traditional energy storage solutions relying on "voltage equalization modules" are unsuitable due to the added weight and system complexity. Furthermore, during parallel charging of multiple battery packs, differences in initial voltage, internal resistance, and SOH (State of Health) among the packs can lead to serious problems such as contactor arcing and uneven current distribution. Parallel charging of multiple battery packs refers to simultaneously charging multiple battery packs (≥2) with a single charging gun.

[0003] How to achieve safe and efficient parallel charging of multiple battery packs without using voltage equalization modules has become a key technical challenge in the design of eVTOL battery systems. Summary of the Invention

[0004] The purpose of this invention is to provide a method, device, system and aircraft for controlling parallel charging of multiple battery packs, so as to achieve safe and efficient parallel charging of multiple battery packs without using a voltage equalization module.

[0005] In a first aspect, the present invention provides a method for controlling parallel charging of multiple battery packs, comprising: Acquire status data of multiple battery packs to be charged, including initial voltage, real-time internal resistance, health status, and rated capacity; Following the order of initial voltage from low to high, the charging circuits of each battery pack are closed sequentially to connect each battery pack to the parallel charging circuit. Before closing the charging circuit of any battery pack to be connected, the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected is monitored. When the voltage difference meets the preset voltage difference condition, the current charging current is adjusted to the pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then the charging circuit of the battery pack to be connected is closed. After all battery packs are connected to the parallel charging circuit, charging control is performed. The charging control includes calculating the total SOC value, which characterizes the overall charging state, based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

[0006] In an optional implementation, adjusting the current charging current to a pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack includes: Calculate the parallel value of the real-time internal resistance of all currently connected battery packs to obtain the equivalent internal resistance; The pre-charge current threshold is calculated based on the ratio of voltage difference to equivalent internal resistance. Adjust the current charging current to the pre-charge current threshold.

[0007] In an optional implementation, a total SOC value characterizing the overall state of charge is calculated based on at least one of the health status and rated capacity of each battery pack, including: The weighting coefficient of each battery pack is determined based on at least one of its health status and rated capacity. The current SOC values ​​of each battery pack are weighted and summed based on their respective weighting coefficients to obtain the total SOC value.

[0008] In an optional implementation, the charging current is dynamically allocated according to the health status of each battery pack, including: The maximum allowable charging current for each battery pack is determined based on its health status. Calculate the sum of the maximum allowable charging currents for each battery pack to obtain the total charging current request value, and control the total charging current of all battery packs based on the total charging current request value. When the actual charging current of any battery pack exceeds its corresponding maximum allowable charging current, the total charging current of all battery packs is reduced.

[0009] In an optional implementation, the charging control further includes: monitoring the SOC value and charging current of each battery pack during the charging process; when the SOC value of any battery pack reaches a preset full charge threshold and its charging current is equal to or lower than a preset trickle charging current threshold, the charging circuit of that battery pack is disconnected, causing it to exit the parallel charging circuit.

[0010] In an optional implementation, the charging control further includes: real-time monitoring of the temperature change rate, voltage change rate, and internal resistance change rate of each battery pack; when the temperature change rate, voltage change rate, and internal resistance change rate of any battery pack exceed their respective preset thresholds, a protection action is triggered, which includes one or more of reducing the charging current, disconnecting the charging circuit of the abnormal battery pack, or activating emergency cooling.

[0011] In a second aspect, the present invention provides a multi-battery pack parallel charging control device, comprising: The data acquisition module is used to acquire the status data of multiple battery packs to be charged. The status data includes initial voltage, real-time internal resistance, health status and rated capacity. The charging access module is used to sequentially close the charging circuits of each battery pack in order of initial voltage from low to high, so as to connect each battery pack to the parallel charging circuit. Before closing the charging circuit of any battery pack to be connected, the module monitors the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected. When the voltage difference meets the preset voltage difference condition, the module adjusts the current charging current to the pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then closes the charging circuit of the battery pack to be connected. The charging control module is used to perform charging control after all battery packs are connected to the parallel charging circuit. The charging control includes calculating the total SOC value, which represents the overall charging state, based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

[0012] Thirdly, the present invention provides a battery management system, including a memory and a processor. The memory stores a computer program that can run on the processor. When the processor executes the computer program, it implements the multi-battery pack parallel charging control method of any of the foregoing embodiments.

[0013] Fourthly, the present invention provides an aircraft including the battery management system of the foregoing embodiments.

[0014] Fifthly, the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, performs the multi-battery pack parallel charging control method of any of the foregoing embodiments.

[0015] The present invention provides a method, apparatus, system, and aircraft for parallel charging control of multiple battery packs. The method includes: acquiring state data of multiple battery packs to be charged, including initial voltage, real-time internal resistance, health status, and rated capacity; sequentially closing the charging circuits of each battery pack in ascending order of initial voltage to connect each battery pack to a parallel charging circuit; wherein, before closing the charging circuit of any battery pack to be connected, monitoring the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected, and when the voltage difference meets a preset voltage difference condition, adjusting the current charging current to a pre-charge current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then closing the charging circuit of the battery pack to be connected; after all battery packs are connected to the parallel charging circuit, performing charging control, which includes calculating a total SOC value characterizing the overall charging state based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

[0016] By introducing state-aware adaptive soft access and dynamic management logic, the reliance on independent voltage equalization modules is removed at the architectural level. In the hardware access stage, based on the initial voltage sorting results, the pre-charge current threshold is dynamically calculated and set by real-time monitoring of the voltage difference and the battery pack's real-time internal resistance. This precisely limits the circulating current instantaneously generated by the contactor in the closed charging circuit to a safe range, achieving the voltage equalization module's function of suppressing inrush current and achieving voltage balancing without additional hardware. In the software management stage, the total SOC value is calculated based on at least one of the health status and rated capacity of each battery pack. This ensures the accuracy of the total SOC value feedback even without voltage equalization modules, and dynamic current allocation is performed based on the health status of each battery pack, achieving the balancing effect of the voltage equalization module at the logical level. Therefore, this invention achieves safe and efficient parallel charging of multiple battery packs without using voltage equalization modules. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating a method for controlling parallel charging of multiple battery packs according to an embodiment of the present invention. Figure 2 A flowchart illustrating another method for controlling parallel charging of multiple battery packs provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a multi-battery pack parallel charging control device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of a battery management system provided in an embodiment of the present invention. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0020] Existing multi-battery pack parallel charging technology has the following drawbacks that conflict with the specific requirements of eVTOL aircraft: 1. Reliance on voltage equalization modules: Existing solutions typically require pre-processing (i.e., pre-equalization) of the battery pack using a separate voltage equalization module (such as an active equalization circuit or a passive equalization resistor) to achieve voltage consistency. However, this approach inevitably increases the overall weight, size, and cost of the system, failing to meet the lightweight requirements of eVTOL aircraft.

[0021] 2. Incompatible parallel connection strategy: The existing solution directly connects the batteries in parallel after equalization, without taking into account the unique high voltage and high power characteristics of the eVTOL battery pack and its real-time state differences (such as internal resistance and SOH), which can easily cause contactor arcing or current backflow.

[0022] 3. Not adapted to eVTOL scenarios: Existing solutions are not optimized for the needs of eVTOL aircraft (such as fast charging and hot-swapping requirements), and cannot balance charging efficiency and safety and reliability.

[0023] Therefore, there is an urgent need to develop a new charging solution that can ensure the safety and reliability of the charging process while meeting the core requirements of eVTOL aircraft for lightweight and high performance.

[0024] This invention provides a method, device, system, and aircraft for controlling parallel charging of multiple battery packs. It adopts a phased parallel connection without a voltage equalization module and a dynamic weighted SOC (State of Charge) fitting method. Through the control logic of "initial voltage sorting → voltage difference-internal resistance dynamic pre-charging → gradual parallel connection", it replaces the traditional voltage equalization module and achieves voltage balancing without additional hardware. Based on the battery pack's SOH, capacity, and current SOC value, a hierarchical weighted model is constructed to ensure the feedback accuracy of the total SOC value without a voltage equalization module.

[0025] To facilitate understanding of this embodiment, a multi-battery pack parallel charging control method disclosed in this embodiment of the invention will first be described in detail.

[0026] This invention provides a method for controlling parallel charging of multiple battery packs, which can be executed by a BMS (Battery Management System). See also Figure 1 The diagram shows a flowchart of a multi-battery pack parallel charging control method, which mainly includes the following steps S110 to S130: Step S110: Obtain status data of multiple battery packs to be charged. The status data includes initial voltage, real-time internal resistance, health status, and rated capacity.

[0027] This step is a preliminary basic testing step for multi-battery pack parallel charging. The core of this step is that the Battery Management System (BMS) accurately collects four key state data of each battery pack to be charged: initial voltage, real-time internal resistance, state of health (SOH), and rated capacity, through corresponding functional units such as voltage sampling, AC injection, and multi-cell joint monitoring. This provides comprehensive and reliable data support for subsequent phased parallel control, accurate SOC calculation, and dynamic current distribution, avoiding charging safety issues caused by unclear state differences.

[0028] Step S120: Following the order of initial voltage from low to high, the charging circuits of each battery pack are closed sequentially to connect each battery pack to the parallel charging circuit. Before closing the charging circuit of any battery pack to be connected, the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected is monitored. When the voltage difference meets the preset voltage difference condition, the current charging current is adjusted to the pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then the charging circuit of the battery pack to be connected is closed.

[0029] This step is the core control link for parallel charging of multiple battery packs without voltage equalization modules. The core logic can be "sorting by voltage, voltage difference verification, current limiting pre-charging, and gradual integration": First, all battery packs to be charged are sorted from low to high initial voltage, and the battery pack with the lowest voltage is connected to the parallel charging circuit in sequence. For each battery pack to be connected, the voltage difference between the battery pack (or battery pack group) already connected to the parallel charging circuit and the battery pack to be connected is monitored in real time. After the voltage difference meets the preset safety conditions (i.e., preset voltage difference conditions), a reasonable pre-charging current threshold is calculated based on the real-time internal resistance (or equivalent internal resistance within the group) of the battery pack already connected. The current charging current is adjusted to the pre-charging current threshold to avoid current surge. Finally, the charging circuit of the battery pack to be connected is closed to ensure that there is no risk of arc discharge or current backflow in each parallel connection, thus achieving safe and orderly multi-pack parallel connection. The aforementioned closed charging circuit for the battery pack to be connected can be a contactor, solid-state relay, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) array, or other switch that closes the charging circuit.

[0030] Step S130: After all battery packs are connected to the parallel charging circuit, charging control is performed. The charging control includes calculating the total SOC value, which represents the overall charging state, based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

[0031] After all battery packs are connected in parallel, the charging control enters the core operation phase, which focuses on balancing the accuracy of charging status feedback with the rationality of current distribution. On the one hand, the weight of each battery pack can be determined based on at least one of its State of Health (SOH) and rated capacity. Combined with the current State of Charge (SOC) of each battery pack, a weighted calculation is performed to obtain the total SOC value that reflects the overall charging status of the entire parallel battery system. This total SOC value is then sent to the charging pile via the communication unit, providing an accurate basis for the charging pile to adjust its charging strategy. On the other hand, the maximum allowable charging current of each battery pack can be determined based on its health status. The total charging current request value is then calculated and fed back to the charging pile. Simultaneously, the actual charging current of each battery pack is monitored in real time. If the actual current of any battery pack exceeds its maximum allowable value, the total charging current is dynamically adjusted to ensure that each battery pack is charged within a safe range, balancing charging efficiency and battery life.

[0032] The multi-battery pack parallel charging control method provided in this invention removes the reliance on independent voltage equalization modules at the architectural level by introducing state-aware adaptive soft access and dynamic management logic. In the hardware access stage, based on the initial voltage sorting results, the pre-charge current threshold is dynamically calculated and set by real-time monitoring of the voltage difference and the real-time internal resistance of the battery packs. This precisely limits the circulating current instantaneously generated by the contactor in the closed charging circuit to a safe range, achieving the voltage equalization module's function of suppressing inrush current and voltage balancing without additional hardware. In the software management stage, the total SOC value is calculated based on at least one of the health status and rated capacity of each battery pack. This ensures the feedback accuracy of the total SOC value even without a voltage equalization module, and dynamic current allocation is performed according to the health status of each battery pack, achieving the balancing effect of the voltage equalization module at the logical level. Therefore, this invention achieves safe and efficient parallel charging of multiple battery packs without using a voltage equalization module.

[0033] For ease of understanding, steps S110 to S130 above will be described in detail below.

[0034] Regarding step S110 above: Specifically, during joint detection of battery pack status, the BMS can detect the initial voltage of multiple battery packs through the voltage sampling unit. (i.e., the first) i The initial voltage of each battery pack is measured, and the real-time internal resistance of each battery pack is detected by the AC injection unit. R i (i.e., the first) i The real-time internal resistance of each battery pack is calculated using a cycle count unit, a capacity decay rate calculation unit, and an internal resistance change rate calculation unit to obtain the health status of each battery pack. (i.e., the first) iThe health status of each battery pack is determined, and the rated capacity of each battery pack is obtained through the capacity calibration unit. (i.e., the first) i (Rated capacity of each battery pack). Additionally, if during the data collection process, if the status data of a battery pack exceeds the preset normal range (e.g., initial voltage too high or too low, internal resistance too high, SOH below the minimum threshold, rated capacity decaying too quickly), the BMS can directly determine that the battery pack is abnormal, immediately isolate it, exclude it from the parallel charging queue, and prompt maintenance personnel for repair, thus preventing abnormal battery packs from affecting the safe operation of the entire charging system.

[0035] One possible implementation involves comprehensively evaluating the battery pack's health by integrating three key indicators: capacity degradation, internal resistance growth, and voltage plateau shift, along with the impact of cycle life on degradation. Based on this, the health status... The following three-factor coupling model can be used for calculation: ; in: For the first i The capacity degradation rate of a battery pack reflects the decline in its ability to store electrical energy. It can be measured by comparing the rated capacity. Compared with actual capacity Obtain, such as ; For the first i The internal resistance growth rate of a battery pack is used to reflect the increase in the internal impedance of the battery pack. It can be compared with the current internal resistance. With initial internal resistance Obtain, such as ; For the first i The voltage plateau offset of a battery pack reflects the stability of its electrochemical characteristics. This can be determined by comparing the current voltage plateau. With the initial voltage plateau Obtain, such as ; For the first i The number of cycles for a battery pack, which reflects its degree of wear and tear, can be obtained by counting the number of charge and discharge cycles of the battery pack. λ This is the decay coefficient for the number of cycles.

[0036] Regarding step S120 above: In some possible embodiments, the aforementioned preset voltage difference condition can be that the voltage difference is less than or equal to the product of the rated voltage of a single battery pack and a preset proportionality coefficient. Wherein, the preset proportionality coefficient... kThe range of values ​​for is (0, 1), that is, 0 < k <1.

[0037] In one possible implementation, the aforementioned preset proportional coefficient k It can be a fixed value preset according to the actual situation.

[0038] In another possible implementation, a preset scaling factor is used. k It can be dynamically updated based on the electrochemical characteristics of the battery pack. Optionally, the update formula for the preset proportional coefficient k can be: ,in, The initial scaling factor is set. This represents the average health status of all battery packs.

[0039] In some possible embodiments, the step of adjusting the current charging current to a pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery packs may include: calculating the parallel value of the real-time internal resistance of all currently connected battery packs to obtain the equivalent internal resistance; calculating the pre-charging current threshold based on the ratio of the voltage difference to the equivalent internal resistance; and adjusting the current charging current to the pre-charging current threshold.

[0040] In one possible implementation, for the case of closing only one battery pack (here referred to as the first battery pack): the pre-charge current threshold = current voltage difference / real-time internal resistance of the first battery pack. The current charging current is precisely adjusted to this pre-charge current threshold by the charging current adjustment unit. For the case of closing two or more battery packs: firstly, the real-time internal resistance of all battery packs connected to the parallel charging circuit can be integrated through parallel resistance calculation logic to obtain the equivalent internal resistance characterizing the overall equivalent impedance; then, based on the voltage difference between the connected battery packs and the battery pack to be connected, the ratio of the voltage difference to the equivalent internal resistance can be calculated using Ohm's law to obtain the pre-charge current threshold that avoids current surges; finally, the current charging current is precisely adjusted to this pre-charge current threshold by the charging current adjustment unit. This method can provide current assurance for the safe parallel connection of the battery packs to be connected, preventing contactor arcing or battery pack damage caused by excessive current.

[0041] In another possible implementation, the pre-charge current threshold can be dynamically adjusted based on the real-time temperature of the battery pack; that is, a temperature compensation factor can be introduced into the pre-charge current threshold. Pre-charge current threshold The calculation formula can be: ;in, For voltage difference, For real-time internal resistance / equivalent internal resistance.

[0042] Optionally, the above temperature compensation factor It can be calculated using the following formula: ;in, For the set temperature coefficient, For the first i Real-time temperature of each battery pack The reference temperature is set. The function of the temperature compensation factor is to dynamically adjust the pre-charge current threshold based on the real-time temperature of the battery pack. By combining the temperature coefficient and the difference between the real-time temperature and the reference temperature, the temperature compensation factor is calculated to obtain the pre-charge current threshold, ensuring that the pre-charge current remains within a reasonable range under different temperature conditions. Specifically, when the real-time temperature of the battery pack deviates from the reference temperature, the temperature compensation factor can offset the effects of temperature changes on the battery's internal resistance and electrochemical characteristics—for example, at low temperatures, the battery's internal resistance increases, and the temperature compensation factor will appropriately lower the pre-charge current threshold to avoid excessive current surges that could cause arcing or component damage; at high temperatures, the current can be adjusted according to the characteristics, balancing pre-charge efficiency and safety, ultimately improving the adaptability and reliability of the pre-charge process.

[0043] Regarding step S130 above: In some possible embodiments, the step of calculating the total SOC value characterizing the overall state of charge based on at least one of the health status and rated capacity of each battery pack may include: determining a weighting coefficient for each battery pack based on at least one of the health status and rated capacity of each battery pack; and performing a weighted summation of the current SOC values ​​of each battery pack based on its weighting coefficient to obtain the total SOC value. The weighting coefficients of the battery packs can be determined based on their health status, their rated capacity, or both.

[0044] Furthermore, the weighting coefficient of the battery pack can also be determined in conjunction with the current SOC value of the battery pack. That is, the weighting coefficient of the battery pack can be determined based on the health status and current SOC value of each battery pack, or based on the rated capacity and current SOC value of each battery pack, or based on the health status, rated capacity and current SOC value of each battery pack.

[0045] In one possible implementation, during charging, after obtaining the current SOC value of each battery pack, its weighting coefficient can be calculated based on the current SOC value, SOH, and rated capacity of each battery pack. i Weighting coefficient of each battery pack The calculation formula can be: Among them, the coefficient α , β , γ All are preset positive numbers and α + β + γ =1, For the first i The current SOC value of each battery pack. For the first i The health status of each battery pack For the first i The rated capacity of each battery pack, For the first j The rated capacity of each battery pack, N This refers to the number of battery packs.

[0046] In some possible embodiments, the step of dynamically allocating charging current based on the health status of each battery pack may include: determining the maximum allowable charging current corresponding to each battery pack based on its health status; calculating the sum of the maximum allowable charging currents corresponding to each battery pack to obtain a total charging current request value, and controlling the total charging current of all battery packs based on the total charging current request value; when the actual charging current of any battery pack exceeds its corresponding maximum allowable charging current, reducing the total charging current of all battery packs. The maximum allowable charging current of a battery pack is the maximum charging current allowed by the battery pack in combination with its cell temperature, voltage, etc.

[0047] In one possible implementation, the above-mentioned... i Maximum permissible charging current for each battery pack It can be the rated charging current. With health status The product of, i.e. .

[0048] In another possible implementation, the above-mentioned... i Maximum permissible charging current for each battery pack A temperature-current coupling model can be introduced for correction, resulting in a maximum allowable charging current. It can be: ;in, The set temperature-current coupling coefficient, It takes effect at a certain time, that is, when the battery's real-time temperature... Exceeding the preset safe reference temperature At this point, the correction formula for the temperature-current coupling model begins to take effect. This is achieved by introducing a temperature-current coupling coefficient. Dynamically reduce the upper limit of charging current This protects the battery from high-temperature damage or potential safety risks.

[0049] After calculating the total charging current request value, the total charging current request value can be sent to the charging pile via the communication unit. If the... i The actual charging current of each battery pack Exceeding its maximum allowable charging current Then, the total current is adjusted in a stepped manner through the total current regulation unit. Optionally, the adjusted total charging current... It can be: ;in, The total charging current before adjustment. The set total current adjustment coefficient. ≥1.

[0050] Furthermore, in some possible embodiments, this embodiment also provides a charging end disconnection control method. The charging control further includes: during the charging process, monitoring the SOC value and charging current of each battery pack; when the SOC value of any battery pack reaches a preset full charge threshold and its charging current is equal to or lower than a preset trickle charging current threshold, the charging circuit of that battery pack is disconnected, causing it to exit the parallel charging circuit.

[0051] Specifically, during the charging process, the real-time state of charge and actual charging current of each parallel battery pack are continuously monitored to establish a precise full-charge judgment mechanism. When the SOC value of any battery pack reaches the preset full-charge threshold (i.e., it is close to or has reached the full charge state), and its actual charging current drops to the preset trickle charging current threshold (or below), it indicates that the battery pack has completed effective charging. At this time, the charging circuit is disconnected by the contactor and other control units to remove it from the parallel charging circuit. This avoids overcharging and damage to the battery pack, and does not affect the normal charging of other battery packs that are not fully charged, thus ensuring the safety of the charging process and the battery life.

[0052] Furthermore, in some possible embodiments, a thermal runaway warning is introduced during the charging process. The charging control also includes: real-time monitoring of the temperature change rate, voltage change rate, and internal resistance change rate of each battery pack; when the temperature change rate, voltage change rate, and internal resistance change rate of any battery pack exceed their respective preset thresholds, a protection action is triggered. The protection action includes reducing the charging current, disconnecting the charging circuit of the abnormal battery pack, or activating one or more of emergency cooling.

[0053] Specifically, a thermal runaway warning is introduced during the charging process, and the warning conditions are as follows: and and ,in, For the rate of temperature change, For the set temperature change rate threshold, The rate of change of voltage. The set voltage change rate threshold, The rate of change of internal resistance, This is a set threshold for the rate of change of internal resistance. When the rate of change of temperature, the rate of change of voltage, and the rate of change of internal resistance of any battery pack simultaneously exceed their respective preset thresholds, a risk of thermal runaway is determined, and a thermal runaway warning is triggered. If a thermal runaway warning is triggered, a three-level protection mechanism can be implemented: firstly, current regulation (reducing the total charging current to 0.5 × 10⁻⁶) is used. I total If the risk is mitigated, the abnormal unit is isolated (by disconnecting the contactor of the warning battery pack), and the core problem is ultimately solved by physical cooling (by activating the emergency cooling system).

[0054] To facilitate understanding, the detailed process of the above-described multi-battery pack parallel charging control method is described below. The multi-battery pack parallel charging control method for eVTOL aircraft includes the following steps: a) Joint battery pack status detection: The battery management system detects the initial voltage of multiple battery packs through a voltage sampling unit. (i.e., the first) i The initial voltage of each battery pack is measured, and the real-time internal resistance of each battery pack is detected by the AC injection unit. R i (i.e., the first) i The real-time internal resistance of each battery pack is calculated using a cycle count unit, a capacity decay rate calculation unit, and an internal resistance change rate calculation unit to obtain the health status of each battery pack. (i.e., the first) i The health status of each battery pack is determined, and the rated capacity of each battery pack is obtained through the capacity calibration unit. (i.e., the first) i (Rated capacity of each battery pack); Sort all battery packs from lowest to highest initial voltage as battery pack 1 to battery pack N (N≥2), that is, battery pack 1 is the battery pack with the lowest initial voltage, and battery pack N is the battery pack with the highest initial voltage.

[0055] b) First-stage parallel control: Close the charging circuit contactor of the first battery pack, and perform constant-voltage pre-charging through the charging current regulation unit; wait for the voltage of the first battery pack... Voltage of the second battery pack voltage difference Meet the preset voltage difference condition ( , This indicates the rated voltage of a single battery pack. k This is a preset scaling factor, 0 < k When <1), the pre-charge current threshold is calculated based on the real-time internal resistance of the first battery pack (pre-charge current threshold = current voltage difference / real-time internal resistance of the first battery pack, i.e. The charging current is adjusted to the pre-charge current threshold by the charging current adjustment unit. Then, close the charging circuit contactor for the second battery pack.

[0056] c) Parallel control in subsequent stages: For the sorted battery packs from the 3rd to the Nth, repeat the following operation: i) Monitor the total voltage of the currently parallel-connected battery packs using the voltage sampling unit. Voltage of the next battery pack to be connected in parallel voltage difference ; ii) When the voltage difference meets the preset voltage difference condition, calculate the equivalent internal resistance (equivalent internal resistance) based on the real-time internal resistance of each battery pack in the currently parallel battery pack group. , For the first j One parallel battery pack, m (This refers to the number of battery packs already connected in parallel), and the pre-charge current threshold is calculated based on this equivalent internal resistance (pre-charge current threshold = current voltage difference / equivalent internal resistance, i.e.: ); iii) Adjust the current charging current to the aforementioned pre-charge current threshold using the charging current adjustment unit. Then, close the charging circuit contactor for the next battery pack to be connected in parallel; The process continues until all battery pack charging circuit contactors are closed, enabling parallel charging of all battery packs.

[0057] d) SOC weighted fitting calculation: During the charging process, the current SOC value of each battery pack is obtained through the SOC calculation unit, and the weight allocation unit calculates the weight based on the current SOC value, SOH and rated capacity of each battery pack. (i.e., the first) i (Weighting coefficient of each battery pack) ,in α , β , γ All are positive numbers and α + β + γ =1), the total SOC value is calculated using a weighted summation unit. The total SOC value is then sent to the charging station via the communication unit.

[0058] e) Dynamic current distribution control: The maximum allowable charging current of each battery pack is obtained through the maximum allowable current calculation unit (maximum allowable charging current = rated charging current × SOH, i.e.: the first...). i Maximum permissible charging current for each battery pack , For the first i The rated charging current of each battery pack is used to calculate the total charging current request value (total charging current request value = sum of the maximum allowable charging current of each battery pack, i.e., the total charging current request value = the sum of the maximum allowable charging current of each battery pack) through the total current calculation unit. The total charging current request value is sent to the charging pile via the communication unit; if the actual charging current of a battery pack is detected by the current sampling unit... Exceeding its maximum allowable charging current Then, the total current is adjusted in a stepped manner through the total current regulation unit, and the adjusted total charging current is: , This is the total current adjustment factor. ≥1.

[0059] f) Charging completion disconnection control: The full charge determination unit monitors whether the SOC of each battery pack has reached the preset SOC threshold and whether the charging current is lower than the preset current threshold. and , To preset the SOC threshold, The threshold for trickle charging current is set. If a battery pack meets the above full-charge condition, the charging circuit contactor of that battery pack is disconnected through the contactor control unit. The charging circuit contactors of all battery packs are disconnected in sequence according to the order in which they meet the full-charge condition.

[0060] Figure 2 The control flow for parallel charging of multiple battery packs in an eVTOL aircraft was demonstrated, mainly including: Pre-charging preparation: Check the battery pack status; when all battery packs are normal, read the parameters of each battery pack, including initial voltage, internal resistance, SOH, and capacity; when there is an abnormal battery pack, isolate the abnormal battery pack and prompt for maintenance. Phased parallel control: The battery packs are sorted from high to low initial voltage, the pre-charge current threshold of the current battery pack to be connected in parallel is calculated, the pre-charge current is adjusted to within the pre-charge current threshold, and then the contactor of the current battery pack to be connected in parallel is closed to be connected into the charging circuit until all battery packs are connected in parallel. Dynamic SOC fitting: Collect the real-time SOC value of each battery pack, build a dynamic weight model based on SOH and capacity, calculate the total SOC value and feed it back to the charging pile; Safety protection: Real-time monitoring of the temperature change rate, voltage change rate, and internal resistance change rate of each battery pack to determine whether a warning condition is triggered; if not, continuous monitoring is performed until charging is complete; if so, a three-level protection mechanism is executed, namely, current reduction → disconnecting the abnormal battery pack → emergency stop.

[0061] In summary, the embodiments of the present invention have the following beneficial effects: Lightweight and minimalist design: By eliminating the equalization module, the system weight and complexity are directly reduced, making it fully compatible with the lightweight requirements of eVTOL aircraft; Safe and efficient parallel operation: By using a phased pre-charging logic, contactor arc discharge and current backflow are avoided, achieving charging safety comparable to traditional voltage equalization solutions without a voltage equalization module. Precise SOC Feedback: The dynamic weighting model ensures the accuracy of total SOC calculation in a parallel architecture without a voltage equalization module, supporting precise charging strategies for charging piles. Scenario adaptability: Supports hot-swappable battery packs and fast charging to meet the actual usage scenario requirements of eVTOL aircraft.

[0062] Corresponding to the above-described multi-battery pack parallel charging control method, this embodiment of the invention also provides a multi-battery pack parallel charging control device. See also... Figure 3 The diagram shows a structural schematic of a multi-battery pack parallel charging control device, which includes: The data acquisition module 301 is used to acquire the status data of multiple battery packs to be charged. The status data includes initial voltage, real-time internal resistance, health status and rated capacity. The charging access module 302 is used to sequentially close the charging circuits of each battery pack in order of initial voltage from low to high, so as to connect each battery pack to the parallel charging circuit. Before closing the charging circuit of any battery pack to be connected, the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected is monitored. When the voltage difference meets the preset voltage difference condition, the current charging current is adjusted to the pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then the charging circuit of the battery pack to be connected is closed. The charging control module 303 is used to perform charging control after all battery packs are connected to the parallel charging circuit. The charging control includes calculating the total SOC value, which represents the overall charging state, based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

[0063] The multi-battery pack parallel charging control device provided in this invention removes the reliance on an independent voltage equalization module at the architectural level by introducing state-aware adaptive soft access and dynamic management logic. In the hardware access stage, based on the initial voltage sorting results, the pre-charge current threshold is dynamically calculated and set by real-time monitoring of the voltage difference and the real-time internal resistance of the battery packs. This precisely limits the circulating current instantaneously generated by the contactor in the closed charging circuit to a safe range, achieving the voltage equalization module's function of suppressing inrush current and voltage balancing without additional hardware. In the software management stage, the total SOC value is calculated based on at least one of the health status and rated capacity of each battery pack. This ensures the feedback accuracy of the total SOC value even without a voltage equalization module, and dynamic current allocation is performed according to the health status of each battery pack, achieving the balancing effect of the voltage equalization module at the logical level. Therefore, this invention achieves safe and efficient parallel charging of multiple battery packs without using a voltage equalization module.

[0064] Furthermore, the charging access module 302 is specifically used to: calculate the parallel value of the real-time internal resistance of all currently connected battery packs to obtain the equivalent internal resistance; calculate the pre-charge current threshold based on the ratio of voltage difference to equivalent internal resistance; and adjust the current charging current to the pre-charge current threshold.

[0065] Furthermore, the charging control module 303 is specifically used to: determine the weighting coefficient of each battery pack based on at least one of the health status and rated capacity of each battery pack; and to perform a weighted summation of the current SOC values ​​of each battery pack based on the weighting coefficient of each battery pack to obtain the total SOC value.

[0066] Furthermore, the charging control module 303 is also used to: determine the maximum allowable charging current corresponding to each battery pack based on the health status of each battery pack; calculate the sum of the maximum allowable charging currents corresponding to each battery pack to obtain the total charging current request value, so as to control the total charging current of all battery packs based on the total charging current request value; and reduce the total charging current of all battery packs when the actual charging current of any battery pack exceeds its corresponding maximum allowable charging current.

[0067] Furthermore, the charging control module 303 is also used to: monitor the SOC value and charging current of each battery pack during the charging process; when the SOC value of any battery pack reaches a preset full charge threshold and its charging current is equal to or lower than a preset trickle charging current threshold, the charging circuit of that battery pack is disconnected, so that it exits the parallel charging circuit.

[0068] Furthermore, the charging control module 303 is also used to: monitor the temperature change rate, voltage change rate, and internal resistance change rate of each battery pack in real time; when the temperature change rate, voltage change rate, and internal resistance change rate of any battery pack exceed their respective preset thresholds, trigger a protection action, which includes one or more of reducing the charging current, disconnecting the charging circuit of the abnormal battery pack, or starting emergency cooling.

[0069] The multi-battery pack parallel charging control device provided in this embodiment has the same implementation principle and technical effect as the aforementioned multi-battery pack parallel charging control method embodiment. For the sake of brevity, any parts not mentioned in the multi-battery pack parallel charging control device embodiment can be referred to the corresponding content in the aforementioned multi-battery pack parallel charging control method embodiment.

[0070] like Figure 4 As shown, an embodiment of the present invention provides a battery management system 400, including a processor 401, a memory 402 and a bus. The memory 402 stores a computer program that can run on the processor 401. When the battery management system 400 is running, the processor 401 and the memory 402 communicate through the bus. The processor 401 executes the computer program to implement the above-mentioned multi-battery pack parallel charging control method.

[0071] Specifically, the memory 402 and processor 401 mentioned above can be general-purpose memory and processor, without any specific limitations here.

[0072] This invention also provides an aircraft that includes the aforementioned battery management system. This aircraft may be, but is not limited to, an eVTOL aircraft.

[0073] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, this computer program performs the multi-battery pack parallel charging control method described in the preceding method embodiments. The computer-readable storage medium includes various media capable of storing program code, such as a USB flash drive, portable hard drive, read-only memory (ROM), RAM, magnetic disk, or optical disk.

[0074] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0075] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0076] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0077] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and there may be other division methods in actual implementation. Furthermore, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the coupling or direct coupling or communication connection shown or discussed may be through some communication interface; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0078] The modules described as separate components may or may not be physically separate. Similarly, the components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0079] In addition, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling parallel charging of multiple battery packs, characterized in that, include: Acquire status data of multiple battery packs to be charged, including initial voltage, real-time internal resistance, health status, and rated capacity; According to the initial voltage from low to high, the charging circuits of each battery pack are closed sequentially to connect each battery pack to the parallel charging circuit; wherein, before closing the charging circuit of any battery pack to be connected, the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected is monitored, and when the voltage difference meets the preset voltage difference condition, the current charging current is adjusted to the pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then the charging circuit of the battery pack to be connected is closed; After all the battery packs are connected to the parallel charging circuit, charging control is performed. The charging control includes calculating the total SOC value, which characterizes the overall charging state, based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

2. The multi-battery pack parallel charging control method according to claim 1, characterized in that, The step of adjusting the current charging current to a pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack includes: Calculate the parallel value of the real-time internal resistance of all currently connected battery packs to obtain the equivalent internal resistance; The pre-charge current threshold is calculated based on the ratio of the voltage difference to the equivalent internal resistance. Adjust the current charging current to the pre-charge current threshold.

3. The multi-battery pack parallel charging control method according to claim 1, characterized in that, The calculation of the total SOC value, which characterizes the overall state of charge, based on at least one of the health status and rated capacity of each battery pack, includes: The weighting coefficient of each battery pack is determined based on at least one of the health status and rated capacity of each battery pack. The total SOC value is obtained by weighting and summing the current SOC values ​​of each battery pack based on their respective weighting coefficients.

4. The multi-battery pack parallel charging control method according to claim 1, characterized in that, The dynamic allocation of charging current based on the health status of each battery pack includes: The maximum allowable charging current is determined based on the health status of each battery pack. Calculate the sum of the maximum allowable charging currents corresponding to each of the battery packs to obtain the total charging current request value, and control the total charging current of all the battery packs based on the total charging current request value; When the actual charging current of any of the battery packs exceeds its corresponding maximum allowable charging current, the total charging current of all the battery packs is reduced.

5. The multi-battery pack parallel charging control method according to claim 1, characterized in that, The charging control further includes: during the charging process, monitoring the SOC value and charging current of each battery pack; when the SOC value of any battery pack reaches a preset full charge threshold and its charging current is equal to or lower than a preset trickle charging current threshold, the charging circuit of that battery pack is disconnected, causing it to exit the parallel charging circuit.

6. The multi-battery pack parallel charging control method according to claim 1, characterized in that, The charging control also includes: real-time monitoring of the temperature change rate, voltage change rate, and internal resistance change rate of each battery pack; when the temperature change rate, voltage change rate, and internal resistance change rate of any battery pack exceed their respective preset thresholds, a protection action is triggered, the protection action including reducing the charging current, disconnecting the charging circuit of the abnormal battery pack, or starting emergency cooling, or one or more of these actions.

7. A multi-battery pack parallel charging control device, characterized in that, include: The data acquisition module is used to acquire the status data of multiple battery packs to be charged, including initial voltage, real-time internal resistance, health status and rated capacity. The charging access module is used to sequentially close the charging circuits of each battery pack in order of increasing initial voltage to connect each battery pack to a parallel charging circuit. Before closing the charging circuit of any battery pack to be connected, the module monitors the voltage difference between the battery pack already connected to the parallel charging circuit and the battery pack to be connected. When the voltage difference meets a preset voltage difference condition, the module adjusts the current charging current to a pre-charging current threshold determined based on the real-time internal resistance of the currently connected battery pack, and then closes the charging circuit of the battery pack to be connected. The charging control module is used to perform charging control after all the battery packs are connected to the parallel charging circuit. The charging control includes calculating the total SOC value, which characterizes the overall charging state, based on at least one of the health status and rated capacity of each battery pack, and / or dynamically allocating the charging current according to the health status of each battery pack.

8. A battery management system, comprising a memory and a processor, wherein the memory stores a computer program executable on the processor, characterized in that, When the processor executes the computer program, it implements the multi-battery pack parallel charging control method according to any one of claims 1-6.

9. An aircraft, characterized in that, Includes the battery management system as described in claim 8.

10. A computer-readable storage medium storing a computer program thereon, characterized in that, The computer program, when executed by the processor, performs the multi-battery pack parallel charging control method according to any one of claims 1-6.

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