Intelligent power distribution system, method and vehicle integrating low-voltage battery bms

Abstract

The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution system and method integrated with a low-voltage battery BMS and a vehicle, and relates to the technical field of battery management systems. The application discloses an intelligent power distribution

Description

Technical Field

[0001] This invention belongs to the field of low-voltage battery power management and intelligent power distribution technology, specifically relating to an intelligent power distribution system, method and vehicle integrating a low-voltage battery BMS. Background Technology

[0002] Low-voltage batteries (such as 12V / 24V / 48V ternary lithium batteries and lithium iron phosphate batteries) are widely used in low-voltage power supply scenarios such as start-stop and backup redundant power supplies for new energy vehicles. Existing technologies generally adopt a scheme of low-voltage lithium battery integrated BMS + independent power distribution box architecture. The BMS is only responsible for monitoring, balancing and charging and discharging control of low-voltage lithium battery cells. The power distribution of the whole vehicle is passively realized by relays and fuses. The two do not work together, which has the following problems: (1) There is no priority management for multiple loads, which is prone to overload, uneven voltage drop and power failure of key loads. Moreover, the health status (i.e., SOH) difference between individual cells is not fully considered, which leads to accelerated decay of cell life; (2) The low-voltage lithium battery integrated BMS + independent power distribution box structure results in more wiring harnesses, larger size, more contacts, higher failure rate, and more complicated maintenance and replacement operations. Overload / overvoltage protection relies on relays and fuses, which are slow to respond and cannot be recovered. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of this application is to provide an intelligent power distribution system, method and vehicle integrating a low-voltage battery management system (BMS) to realize dynamic adjustment of cell health status and intelligent power distribution of multiple load modules.

[0004] In a first aspect, this application provides an intelligent power distribution system integrating a low-voltage battery management system (BMS), comprising a BMS control unit and a low-voltage battery, a DC-DC converter unit, and a multi-channel power distribution module communicatively connected to the BMS control unit. The BMS control unit includes a main control chip and a cell group voltage sampling circuit, a cell group current sampling circuit, a cell group temperature sampling circuit, and an active balancing circuit electrically connected to the main control chip. The low-voltage battery has m cell groups. The DC-DC converter unit includes m bidirectional DC-DC converters, the input terminals of which are electrically connected to the m cell groups respectively, and the output terminals of which are electrically connected to the input terminals of the multi-channel power distribution module. The multiple output terminals of the multi-channel power distribution module are electrically connected to multiple low-voltage load modules respectively. The main control chip can control the m bidirectional DC-DC converters and the multi-channel power distribution module to connect any low-voltage load module to any cell group.

[0005] For each of the m cell groups in a low-voltage battery, m bidirectional DC-DC converters are configured. The input of each bidirectional DC-DC converter is individually connected to a single cell group, enabling independent and controllable conversion and transmission of voltage, power, and current for each cell group. When a single cell group experiences overvoltage, undervoltage, short circuit, or abnormal temperature rise, the main control chip can cut off the output path of the corresponding bidirectional DC-DC converter, isolating only the faulty cell group. The remaining intact cell groups can still supply power normally through the matching bidirectional DC-DC converters, improving the redundancy of the vehicle's low-voltage power supply and driving safety. The main control chip can control multi-channel power distribution modules, enabling any low-voltage load module to be connected to any cell group on demand. This helps avoid accelerated aging caused by long-term high-power deep discharge of a single cell group, making the charging and discharging losses of each cell group more consistent, and ensuring uniform capacity decay throughout the low-voltage battery's life cycle.

[0006] Secondly, this application provides an intelligent power distribution method integrating a low-voltage battery management system (BMS). Employing the aforementioned intelligent power distribution system integrating a low-voltage battery management system (BMS), the method includes:

[0007] Obtain the temperature, voltage, SOC, SOH of each cell group, as well as the real-time power requirements of each low-voltage load module.

[0008] Based on the SOC and SOH of each cell group, the power distribution weight of each cell group is determined.

[0009] The power distribution of each battery cell group is determined based on the power distribution weight of each cell group and the real-time power demand of each low-voltage load module.

[0010] Based on the voltage and power distribution of each cell group, the theoretical discharge current of each cell group is determined.

[0011] Based on the SOH, rated discharge rate, and rated capacity of each cell group, the maximum allowable discharge current of each cell group is determined.

[0012] The minimum value between the theoretical discharge current and the maximum allowable discharge current of each cell group is taken as the final discharge current of each cell group, and the final discharge current is sent as a control command to the corresponding bidirectional DC-DC converter.

[0013] The power distribution weight is determined by the SOC and SOH of the cell group. Based on this weight, the power distribution of each cell group is obtained by matching the sum of the real-time power demands of each low-voltage load module. This allows cell groups with high health and sufficient remaining charge to bear more load power, while aging and depleted cell groups share a smaller load. This balances the charging and discharging losses of each cell group, slows down the differentiated degradation of cells, and helps extend the overall service life of the low-voltage battery. On the one hand, the theoretical discharge current is calculated by combining the voltage and power distribution of the cell group. On the other hand, the maximum allowable discharge current of each cell group is dynamically calibrated based on SOH, rated discharge rate, and rated capacity. The minimum of the two is taken as the actual output current (i.e., the final discharge current) and sent to the bidirectional DC-DC converter. This ensures the normal power supply to the low-voltage load module and limits the output current in real time according to the aging degree and discharge tolerance of the cell group, achieving a dual balance between power supply performance and battery safety. Independent and precise current limiting and power control for each cell group enables independent flexible power adjustment of a single cell group, further improving the redundancy of low-voltage power supply and the intelligent level of battery life cycle management.

[0014] Optionally, methods for determining the power distribution weights of each cell group include:

[0015] Using the formula: Calculate the discharge SOC equalization weight of the i-th cell group. Where k represents the preset first acceleration factor, k≥1.

[0016] Using the formula: Calculate the optimal weights for the discharge SOH of the i-th cell group. Where p represents the preset second acceleration factor, p≥1.

[0017] Using the formula: The power distribution weight of the i-th cell group is calculated. .

[0018] A power-law weighting formula is used to calculate the discharge SOC balancing weight and discharge SOH optimization weight for each cell group. First and second acceleration factors, each not less than 1, amplify the differences in SOC and SOH between cell groups. The weights of high-capacity, high-health cell groups are significantly increased, while the weights of aging, low-capacity cell groups are automatically reduced. This strengthens the differentiated load allocation effect among cell groups and helps to quickly reduce the capacity and health gaps between them. Multiplying and normalizing these two types of weights yields a comprehensive power distribution weight that simultaneously considers both remaining capacity balancing and cell health protection. This avoids the shortcomings of single-parameter weighting, which tends to favor capacity allocation while neglecting cell aging damage. The power distribution logic aligns with the requirements for full-lifecycle loss management of batteries.

[0019] Optionally, the power distribution of each cell group can be determined as follows:

[0020] Using the formula: The power distribution of the i-th cell group is calculated. ;in, This represents the sum of real-time power requirements of each low-voltage load module, where i takes all integer values ​​from 1 to m. The power distribution of a single battery cell group is obtained by multiplying the total power of the low-voltage load modules by the corresponding power distribution allocation weight. The calculation logic is simple and the calculation time is short, which reduces the computational load on the main control chip and ensures real-time power distribution output.

[0021] Optionally, the theoretical discharge current of each cell group can be determined as follows:

[0022] Using the formula: The theoretical discharge current of the i-th cell group is calculated. ;in, This represents the voltage of the i-th cell group. The theoretical discharge current is directly calculated using the Ohm's power formula based on the power distribution allocated to each cell group and the real-time terminal voltage (i.e., the voltage of the corresponding cell group). The calculation logic is simple and the computational load is small.

[0023] Optionally, methods for determining the maximum permissible discharge current of each cell group include:

[0024] First, use the formula: Calculate the maximum allowable discharge rate of the i-th cell group. ;in, This indicates the rated discharge rate of each cell group. Indicates about an increasing function, .

[0025] Reuse formula: The maximum allowable discharge current of the i-th cell group is calculated. ;in, This indicates the rated capacity of each battery cell pack.

[0026] By using an increasing function related to SOH (State of Health), the rated discharge rate is attenuated and corrected. The lower the cell health status, the lower the maximum permissible discharge rate can be adjusted accordingly. This accurately matches the discharge tolerance of aging cells, preventing overheating and accelerated degradation caused by continuous high-rate discharge of aged cells. The maximum permissible discharge rate, obtained through correction, is combined with the rated capacity of the cell pack to calculate the maximum permissible discharge current, establishing a quantitative mapping relationship between cell health and current limits. These limits are dynamically and adaptively adjusted according to the degree of cell aging, and the control logic aligns with the safety protection requirements throughout the battery's entire lifecycle.

[0027] Optionally, if the total power of the low-voltage battery is less than the sum of the real-time power requirements of each low-voltage load module, then the low-priority low-voltage load modules are disconnected according to the preset low-priority order. When the total power of the low-voltage battery cannot meet the total demand of all low-voltage load modules, the low-priority low-voltage load modules are disconnected in stages according to the preset low-voltage load module priority, prioritizing the uninterrupted power supply to high-priority safety loads such as vehicle control and instruments, effectively avoiding driving safety hazards caused by power failure of critical low-voltage equipment in the vehicle.

[0028] Optionally, during the discharge process of each cell group, when the SOC of a certain cell group is less than or equal to a preset discharge prohibition SOC threshold, the cell group is stopped from discharging (even if the final discharge current of the cell group is 0). Setting the discharge prohibition SOC threshold as the cell group shutdown judgment condition, when the SOC of the cell group drops to the discharge prohibition SOC threshold, the discharge current is directly set to zero and the output is stopped, which can prevent the cell group from deep discharge and extend the service life of the low-voltage battery. Individual cell groups are judged and shut down independently, only isolating cell groups with low SOC, while the remaining cell groups can output normally under load, maintaining system power supply redundancy, and preventing the entire vehicle's low-voltage power from being cut off due to the depletion of a single cell group.

[0029] Optionally, during the low-voltage battery charging phase, the charging current of each cell group is obtained using the following method:

[0030] Obtain the temperature, voltage, SOC, SOH, and total charging current of each cell group.

[0031] Based on the SOC and SOH of each cell group, the charging current allocation weight of each cell group is determined.

[0032] Based on the charging current allocation weight of each cell group and the total charging current of the low-voltage battery, the theoretical charging current of each cell group is determined.

[0033] Based on the temperature and SOH of each cell group, the maximum allowable charging current of each cell group is determined.

[0034] The minimum value between the theoretical charging current and the maximum allowable charging current of each cell group is used as the final charging current of each cell group and sent to the corresponding bidirectional DC-DC converter.

[0035] By combining the SOC and SOH of the cell groups, the total charging current is weighted and distributed to balance the charging progress of each cell group, reduce the cell voltage difference, and slow down capacity degradation. Based on the cell temperature and SOH, the maximum allowable charging current of each cell group is dynamically calibrated, and high-temperature or aging cell groups automatically have their charging safety upper limit lowered. The minimum value between the theoretical charging current and the maximum allowable charging current is taken as the final charging current and sent to the bidirectional DC-DC converter. This matches the overall charging power demand while simultaneously constraining the charging upper limit of individual cell groups in real time, balancing charging efficiency and cell charging safety, and achieving independent and controllable balanced charging closed-loop management of multiple cell groups.

[0036] Optionally, methods for determining the charging current allocation weights for each cell group include:

[0037] Using the formula: Calculate the charging SOC equalization weight of the i-th cell group. Where k represents the preset first acceleration factor, k≥1.

[0038] Using the formula: Calculate the optimal weights for the state of charge (SOH) of the i-th cell group. Where p represents the preset second acceleration factor, p≥1.

[0039] Using the formula: The charging current allocation weight of the i-th cell group is calculated. .

[0040] use Constructing a charging SOC balancing weight By employing a first acceleration factor k of not less than 1 to amplify the differences in remaining charging capacity among different groups, the depleted cell group receives a higher allocation weight, is prioritized for replenishment, and the SOC voltage difference between cell groups is quickly reduced, thus improving the charging balancing effect. Constructing charging SOH optimization weights By leveraging a second acceleration factor p to amplify the differences in cell aging, cells with poor health are given a higher weight, while those with low health are charged more frequently to slow down the impact of capacity decay. The two weights are multiplied and normalized to obtain a comprehensive charging current allocation weight, simultaneously addressing both power balance and cell aging protection.

[0041] Optionally, the theoretical charging current of each cell group can be determined as follows:

[0042] Using the formula: The theoretical charging current of the i-th cell group is calculated. Let i take any integer from 1 to m. The theoretical charging current of a single cell group is calculated by multiplying the charging current allocation weights by the total charging current of the low-voltage battery. The calculation formula is simple and the amount of calculation is small, which helps to reduce the computational load of the main control chip.

[0043] Optionally, the maximum allowable charging current for each cell group can be determined as follows:

[0044] Based on the temperature and state of equilibrium (SOH) of the i-th cell group, a preset table mapping temperature, SOH, and maximum allowable charging current is consulted to obtain the maximum allowable charging current for the i-th cell group. By relying on this preset mapping table lookup method and matching the corresponding maximum allowable charging current with the cell group's temperature and SOH, complex real-time iterative calculations are eliminated, significantly reducing the real-time computing power consumption of the main control chip and resulting in a fast charging current limiting response speed.

[0045] Optionally, the charge / discharge voltage window for the i-th cell group is: ;in, This represents the discharge cutoff voltage of the i-th cell group after compensation. This represents the charging cutoff voltage of the i-th cell group after compensation, where i takes any integer value from 1 to m.

[0046] The discharge cutoff voltage The method of obtaining it is as follows:

[0047] Using the formula: Calculate the theoretical discharge cutoff voltage of the i-th cell group. ;in, This indicates the preset reference standard SOH. Indicates the default and The corresponding discharge cutoff reference voltage, This represents the preset discharge lower limit compensation coefficient. .

[0048] Using the formula: The discharge cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the maximum value. This indicates the preset lower limit of the absolute voltage for cell chemical safety.

[0049] The charging cutoff voltage The method of obtaining it is as follows:

[0050] Using the formula: Calculate the theoretical charging cutoff voltage of the i-th cell group. ;in, Indicates the default and The corresponding charging cutoff reference voltage, This represents the preset charging upper limit compensation coefficient. .

[0051] Using the formula: The charging cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the minimum value. This indicates the preset upper limit of the absolute voltage for cell chemical safety.

[0052] The charging and discharging cutoff voltage is dynamically adjusted based on the relative state of health (SOH) of the cell assembly to a benchmark. As cells age and SOH decreases, the discharge cutoff voltage is automatically raised and the charging cutoff voltage is lowered, reducing irreversible damage to aging cells from deep charging and discharging and slowing down cell degradation. A compensation coefficient is introduced, making the voltage correction range controllable and avoiding excessive capacity loss due to large cutoff voltage deviations. Simultaneously, hard boundary constraints are set for the upper and lower limits of the cell's chemical safety absolute voltage to prevent the corrected voltage from exceeding the cell's inherent safety threshold, eliminating the risk of thermal failure caused by overcharging and over-discharging. Each cell assembly independently generates its own dedicated charging and discharging voltage window to adapt to inconsistent aging conditions across multiple cell assemblies, achieving differentiated voltage protection.

[0053] Optionally, the charge / discharge voltage window for the i-th cell group is: ;in, This represents the discharge cutoff voltage of the i-th cell group after compensation. This represents the charging cutoff voltage of the i-th cell group after compensation, where i takes any integer value from 1 to m.

[0054] The discharge cutoff voltage The method of obtaining it is as follows:

[0055] Using the formula: Calculate the theoretical discharge cutoff voltage of the i-th cell group. ;in, This indicates the preset reference standard SOH. Indicates the default and The corresponding discharge cutoff reference voltage, This represents the preset discharge lower limit compensation coefficient. , This represents the preset third acceleration factor. .

[0056] Using the formula: The discharge cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the maximum value. This indicates the preset lower limit of the absolute voltage for cell chemical safety.

[0057] The charging cutoff voltage The method of obtaining it is as follows:

[0058] Using the formula: Calculate the theoretical charging cutoff voltage of the i-th cell group. ;in, Indicates the default and The corresponding charging cutoff reference voltage, This represents the preset charging upper limit compensation coefficient. .

[0059] Using the formula: The charging cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the minimum value. This indicates the preset upper limit of the absolute voltage for cell chemical safety.

[0060] The charge / discharge cutoff voltage correction introduces a third acceleration factor γ greater than 1 to exponentially amplify the SOH difference. The greater the deviation of the SOH of the cell group from the reference value, the nonlinear magnitude of the charge / discharge cutoff voltage correction intensifies. For severely aged cells, the lower limit of the discharge cutoff voltage is significantly raised and the upper limit of the charging cutoff voltage is lowered, which precisely suppresses lithium plating and irreversible plate losses caused by deep charge and discharge, and enhances the protection effect of aged cells.

[0061] Optionally, during the charging process of each cell group, when the voltage of a certain cell group is greater than or equal to the compensated charging cutoff voltage of that cell group, charging of that cell group is stopped (even if the final charging current of that cell group is 0). Using the independently compensated charging cutoff voltage of each cell group as the shutdown threshold, when the voltage of a cell group reaches the limit, the charging current is directly set to zero and the charging circuit is cut off, precisely preventing continuous overcharging of the cell group. Employing independent control logic for each cell group, only cell groups whose voltage has reached the upper limit are shut down, while the remaining cell groups can continue charging, preserving the balanced control capability of multi-cell group collaborative charging and improving charging efficiency.

[0062] Thirdly, this application provides a vehicle that includes the aforementioned intelligent power distribution system integrating a low-voltage battery management system (BMS). Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments of this application will be described below.

[0064] Figure 1 This is a schematic diagram of the vehicle in an embodiment of this application.

[0065] Figure 2 This is a diagram of the intelligent power distribution system architecture integrating a low-voltage battery management system (BMS) in an embodiment of this application.

[0066] Figure 3 This is a flowchart of the intelligent power distribution method integrating a low-voltage battery management system (BMS) in an embodiment of this application.

[0067] Figure 4 This is a flowchart illustrating the method for obtaining the charging current of each battery cell group in the embodiments of this application. Detailed Implementation

[0068] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0069] like Figure 1 As shown, Figure 1 This is a schematic diagram of a vehicle in an embodiment of this application. The vehicle may be, but is not limited to, a pure electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range-extended electric vehicle (REEV), a plug-in hybrid electric vehicle (PHEV), or a new energy vehicle.

[0070] like Figure 1 As shown, the vehicle in this application embodiment includes the intelligent power distribution system with integrated low-voltage battery management system (BMS) in this application embodiment.

[0071] like Figure 2As shown in the embodiment of this application, the intelligent power distribution system integrating a low-voltage battery management system (BMS) includes a BMS control unit 1, a low-voltage battery 2, a DC-DC converter unit 3, and a multi-channel power distribution module 4. The BMS control unit 1 includes a main control chip 11 and cell group voltage sampling circuit 12, cell group current sampling circuit 13, cell group temperature sampling circuit 14, and active balancing circuit 15, all electrically connected to the main control chip 11. The low-voltage battery 2 has m cell groups, and the DC-DC converter unit 3 includes m bidirectional DC-DC converters 31. The cell group voltage sampling circuit 12, cell group current sampling circuit 13, and cell group temperature sampling circuit 14 are electrically connected to the low-voltage battery 2, collecting the voltage, current, and temperature of the m cell groups. The main control chip 11 is electrically connected to m bidirectional DC-DC converters 31 and controls the bidirectional DC-DC converters 31 to work. The main control chip 11 is also electrically connected to the control terminal of the multi-channel power distribution module 4. The input terminals of the m bidirectional DC-DC converters 31 are electrically connected to m battery cell groups respectively. The output terminals of the m bidirectional DC-DC converters 31 are electrically connected to the input terminals of the multi-channel power distribution module 4. The multiple output terminals of the multi-channel power distribution module 4 are electrically connected to multiple low-voltage load modules respectively. The main control chip 11 can control the m bidirectional DC-DC converters 31 and the multi-channel power distribution module 4 to connect any low-voltage load module to any battery cell group.

[0072] As an example, m cell groups are connected in series to form a low-voltage lithium battery. Each cell group can consist of a single cell or multiple cells connected in series. The main control chip 11 can obtain the real-time power demand of each low-voltage load module and the total charging current of the low-voltage battery from the bus. The bidirectional DC-DC converter 31 can convert the energy of the cell group into a stable low-voltage DC output in the forward direction, or it can draw power in the reverse direction to charge the cell group. The multi-channel power distribution module 4 includes multiple electronic fuses (eFuse), a power switch array, a drive circuit, an NTC temperature acquisition circuit, a sampling unit, etc. Each channel is independently configured with a power switch and a fault isolation unit. Each channel is independently configured with overcurrent / overvoltage / overtemperature / reverse connection / short circuit protection thresholds. The multi-channel power distribution module 4 is integrated with the BMS control unit 1 on the same board or in the same case. By receiving BMS control commands, it performs on / off switching, current limiting, protection, and scheduling for multiple loads. The system employs an electronic fuse (eFuse) to enable rapid disconnection of the corresponding circuit when the vehicle controller malfunctions, and can achieve automatic retry, interlocking, and remote reset. The eFuse supports programmable disconnection, automatic retry, interlocking protection, and remote reset, with a short-circuit protection response time of ≤10μs.

[0073] The low-voltage battery management system (BMS) is integrated with the vehicle's low-voltage intelligent power distribution system, sharing a single BMS control unit as the core scheduling hub. This eliminates the traditional separate architecture where the BMS management device, independent DC-DC power conversion device, and separate power distribution box are independent and separately arranged. On one hand, this significantly reduces the number of independent control chips, external communication harnesses, signal connectors, and mounting housings used in the system, lowering hardware material costs, reducing the complexity of vehicle wiring harness layout and assembly time, and reducing the space occupied in the vehicle chassis / engine compartment, which is conducive to the miniaturization and lightweighting of the vehicle's low-voltage system. On the other hand, it eliminates communication delays, protocol compatibility issues, and signal transmission interference problems between multiple independent controllers, improving the overall response consistency and system reliability of low-voltage power management and power distribution control.

[0074] like Figure 3 As shown, the intelligent power distribution method integrating a low-voltage battery management system (BMS) in this embodiment of the application adopts the aforementioned intelligent power distribution system integrating a low-voltage battery management system (BMS). The method (executed by the main control chip 11) includes the following steps:

[0075] S11. Obtain the temperature, voltage, SOC, SOH of each cell group, and the real-time power requirements of each low-voltage load module.

[0076] As an example, the temperature of each cell group is collected by the cell group temperature sampling circuit 14, and the voltage of each cell group is collected by the cell group voltage sampling circuit 12. The current of each cell group collected by the cell group current sampling circuit 13 is integrated over time (i.e., ampere-hour integration) and then combined with Kalman filtering to obtain the SOC of each cell group, which is existing technology. The internal resistance of each cell group is determined based on its temperature and SOC, and the SOH of each cell group is estimated in real time based on its internal resistance using extended Kalman filtering or recursive least squares algorithm, which is also existing technology.

[0077] S12. Based on the SOC and SOH of each cell group, determine the power distribution weight of each cell group.

[0078] In one possible embodiment, the method for determining the power distribution weight of each cell group is as follows:

[0079] First, use the formula: Calculate the discharge SOC equalization weight of the i-th cell group. Where k represents the preset first acceleration factor, k≥1. The larger the value of k, the greater the degree to which the SOC difference is amplified, and the faster the balancing speed. As an example, k=2.

[0080] Reuse formula: Calculate the optimal weights for the discharge SOH of the i-th cell group. Where p represents the preset second acceleration factor, p≥1. The larger the p value, the greater the degree to which the SOH difference is amplified. As an example, p=1.8.

[0081] Finally, using the formula: The power distribution weight of the i-th cell group is calculated. .

[0082] When the State of Charge (SOC) of different cell groups differs significantly, the discharge SOC balancing weight plays a dominant role, with cell groups having a significantly higher SOC having a larger weight. The system prioritizes SOC balancing, and the impact of SOH differences is suppressed. When the SOC of each cell group tends to be balanced, the discharge SOC balancing weights of each cell group are basically similar, and the weights are mainly determined by the discharge SOH optimization weight. At this time, cell groups with higher SOH begin to bear more output. When the SOC of a certain high-SOH cell group is low, its discharge SOC balancing weight is smaller, which will lower the overall weight and prevent it from being discharged first, thus protecting it.

[0083] S13. Based on the power distribution weight of each battery cell group and the real-time power demand of each low-voltage load module, determine the power distribution of each battery cell group.

[0084] In one possible embodiment, the power distribution of each cell group is determined as follows:

[0085] Using the formula: The power distribution of the i-th cell group is calculated. ;in, This represents the sum of the real-time power requirements of each low-voltage load module, where i takes all integer values ​​from 1 to m.

[0086] S14. Based on the voltage and power distribution of each cell group, determine the theoretical discharge current of each cell group.

[0087] In one possible embodiment, the theoretical discharge current of each cell group is determined as follows:

[0088] Using the formula: The theoretical discharge current of the i-th cell group is calculated. .in, This represents the voltage of the i-th cell group. The bidirectional DC / DC converter outputs in constant current mode, allowing cell groups with higher power distribution weights to output more power, and cell groups with lower power distribution weights to output less power.

[0089] S15. Based on the SOH, rated discharge rate, and rated capacity of each cell group, determine the maximum allowable discharge current of each cell group.

[0090] In addition to the power distribution weighting, a hard discharge current limit (i.e., maximum allowable discharge current) needs to be set for the battery pack to prevent short-term high current pulses from accelerating its degradation.

[0091] In one possible embodiment, the method for determining the maximum permissible discharge current of each cell group includes:

[0092] First, use the formula: Calculate the maximum allowable discharge rate of the i-th cell group. ;in, This indicates the rated discharge rate of each cell group. Indicates about an increasing function, .

[0093] As an example, .when hour, ;when hour, .

[0094] Using the formula: The maximum allowable discharge current of the i-th cell group is calculated. ;in, This indicates the rated capacity of each battery cell pack.

[0095] S16. The minimum value between the theoretical discharge current and the maximum allowable discharge current of each cell group is taken as the final discharge current of each cell group and sent to the corresponding bidirectional DC-DC converter 31.

[0096] Power distribution weights are assigned based on the State of Charge (SOC) and State of Harshness (SOH) of each cell group. This power distribution, combined with the total load power, allocates power to each cell group, allowing cells in good condition to handle more load while reducing the output of aging or depleted cells. This balances charging and discharging losses, slows cell degradation, and extends battery life. The theoretical discharge current is calculated using the cell group's voltage and power distribution. The maximum allowable discharge current is then determined by combining the SOH, rated discharge rate, and rated capacity. The minimum of these two values ​​is used as the command sent to the bidirectional DC-DC converter. This method satisfies the power demands of low-voltage loads while limiting the output current based on cell aging, thus balancing power supply performance and battery safety.

[0097] In one possible embodiment, if the total power of the low-voltage battery is less than the sum of the real-time power requirements of each low-voltage load module, the low-priority low-voltage load modules are disconnected according to a preset priority order from low to high. For example, safety-critical load modules (such as braking and steering) have the highest priority, followed by comfort load modules, and then entertainment load modules. A safety load that is currently operating (such as power steering at high speed) has extremely high priority and will never be mistakenly disconnected; while a non-safety load (such as an entertainment load), even if it has high power, will be normally disconnected (i.e., stop working) when the low-voltage battery is low on power, even if it has low priority.

[0098] In one possible embodiment, during the discharge process of each cell group, when the SOC of a certain cell group is less than or equal to a preset discharge prohibition SOC threshold, the cell group is stopped from discharging (even if the final discharge current of the cell group is 0). As an example, the preset discharge prohibition SOC threshold ranges from 10% to 15%.

[0099] like Figure 4 As shown, during the low-voltage battery charging phase, the charging current of each cell group is obtained using the following method:

[0100] S21. Obtain the temperature, voltage, SOC, SOH and total charging current of each cell group.

[0101] S22. Based on the SOC and SOH of each cell group, determine the charging current allocation weight of each cell group.

[0102] In one possible embodiment, the method for determining the charging current allocation weight of each cell group is as follows:

[0103] First, use the formula: Calculate the charging SOC equalization weight of the i-th cell group. Where k represents the preset first acceleration factor, k≥1. When there is a SOC difference between the cell groups, the cell group with the lower SOC should be given more charging current to quickly narrow the SOC gap. The lower the SOC of the cell group, the greater the SOC balancing weight during charging.

[0104] Reuse formula: Calculate the optimal weights for the state of charge (SOH) of the i-th cell group. Where p represents the preset second acceleration factor, p≥1. Based on SOC balancing, further consideration is given to charging low SOH cell groups more to mitigate the impact of capacity decay. The lower the SOH, the greater the weight of SOH optimization during charging.

[0105] Finally, using the formula: The charging current allocation weight of the i-th cell group is calculated. .

[0106] When there are significant differences in State of Charge (SOC), the SOC balancing weight dominates, with cell groups having low SOC receiving overwhelming charging current. Cell groups with high State of Harmony (SOH) and low SOC also receive high weight due to their low SOC, resulting in rapid charging. Once the SOC is basically balanced, the SOC balancing weights of each battery group become similar, and the SOH optimization weight begins to play a role. Cell groups with low SOH receive a slightly larger share of charging to maintain their SOC stability and alleviate capacity imbalance. If a cell group has both high SOH and high SOC, its SOC balancing weight and SOH optimization weight are small, resulting in an extremely low total weight (i.e., charging current allocation weight), and it receives almost no charging until other cell groups catch up.

[0107] S23. Based on the charging current allocation weight of each cell group and the total charging current of the low-voltage battery, determine the theoretical charging current of each cell group.

[0108] In one possible embodiment, the theoretical charging current of each cell group is determined as follows:

[0109] Using the formula: The theoretical charging current of the i-th cell group is calculated. i takes any integer from 1 to m.

[0110] S24. Based on the temperature and SOH of each cell group, determine the maximum allowable charging current of each cell group.

[0111] In one possible embodiment, the maximum allowable charging current for each cell group is determined as follows:

[0112] Based on the temperature and SOH of the i-th cell group, the maximum allowable charging current of the i-th cell group is obtained by querying the preset correspondence table between temperature, SOH and maximum allowable charging current.

[0113] S25. The minimum value between the theoretical charging current and the maximum allowable charging current of each cell group is taken as the final charging current of each cell group (to prevent overcharging) and sent to the corresponding bidirectional DC-DC converter 31.

[0114] By performing linear / nonlinear compensation of the charge / discharge voltage window within the standard charge / discharge voltage window based on the SOH deviation, high SOH cell packs can operate in a wider window to handle more throughput, while low SOH cell packs can operate in a narrower window to delay aging, thereby reducing the electrical stress on aging cell packs.

[0115] In one possible embodiment, the charge / discharge voltage window of the i-th cell group is: .in, This represents the discharge cutoff voltage of the i-th cell group after (linear) compensation. This represents the charging cutoff voltage of the i-th cell group after (linear) compensation, where i takes all integers from 1 to m.

[0116] Discharge cutoff voltage The method of obtaining it is as follows:

[0117] Using the formula: Calculate the theoretical discharge cutoff voltage of the i-th cell group. .in, This indicates the preset reference standard SOH. Indicates the default and The corresponding discharge cutoff reference voltage, This represents the preset discharge lower limit compensation coefficient. As an example, , Taking a battery pack consisting of a single cell as an example, we will illustrate the lithium iron phosphate battery pack. Ternary lithium battery pack .

[0118] Using the formula: The discharge cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the maximum value. This indicates the preset lower limit of the absolute voltage for cell chemical safety. As an example, a lithium iron phosphate battery pack... Ternary lithium battery pack .

[0119] Taking a lithium iron phosphate battery pack as an example, the discharge cutoff voltage of the i-th cell group after linear compensation See Table 1 for some of the possible values.

[0120] Table 1

[0121]

[0122] Charging cutoff voltage The method of obtaining it is as follows:

[0123] Using the formula: Calculate the theoretical charging cutoff voltage of the i-th cell group. ;in, Indicates the default and The corresponding charging cutoff reference voltage, This represents the preset charging upper limit compensation coefficient. As an example, Taking a battery pack consisting of a single cell as an example, we will illustrate the lithium iron phosphate battery pack. Ternary lithium battery pack .

[0124] Using the formula: The charging cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the minimum value. This indicates the preset absolute voltage limit for cell chemical safety. As an example, a lithium iron phosphate battery pack... Ternary lithium battery pack .

[0125] Taking a lithium iron phosphate battery pack as an example, the charging cutoff voltage of the i-th cell after linear compensation is... See Table 2 for some of the possible values.

[0126] Table 2

[0127]

[0128] Taking lithium iron phosphate battery packs as an example, the charge and discharge voltage window of the i-th cell pack after linear compensation is shown in Table 3.

[0129] Table 3

[0130]

[0131] In one possible embodiment, the charge / discharge voltage window of the i-th cell group is: .in, This represents the discharge cutoff voltage of the i-th cell group after (nonlinear) compensation. This represents the charging cutoff voltage of the i-th cell group after (non-linear) compensation, where i takes all integers from 1 to m.

[0132] Discharge cutoff voltage The method of obtaining it is as follows:

[0133] Using the formula: Calculate the theoretical discharge cutoff voltage of the i-th cell group. .in, This indicates the preset reference standard SOH. Indicates the default and The corresponding discharge cutoff reference voltage, This represents the preset discharge lower limit compensation coefficient. , This represents the preset third acceleration factor. As an example, as an example, , , This allows the window to shrink faster and provide more active protection when SOH is low.

[0134] Using the formula: The discharge cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the maximum value. This indicates the preset lower limit of the absolute voltage for cell chemical safety.

[0135] Charging cutoff voltage The method of obtaining it is as follows:

[0136] Using the formula: Calculate the theoretical charging cutoff voltage of the i-th cell group. ;in, Indicates the default and The corresponding charging cutoff reference voltage, This represents the preset charging upper limit compensation coefficient. As an example, .

[0137] Using the formula: The charging cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the minimum value. This indicates the preset upper limit of the absolute voltage for cell chemical safety.

[0138] In one possible embodiment, during the charging process of each cell group, when the voltage of a certain cell group is greater than or equal to the compensated charging cutoff voltage of that cell group, the charging of that cell group is stopped (even if the final charging current of that cell group is 0). Using the independently compensated charging cutoff voltage of each cell group as the shutdown judgment threshold, when the voltage of a cell group reaches the limit, the charging current is directly set to zero and the charging circuit is cut off, precisely avoiding continuous overcharging of the cell group.

[0139] Finally, it should be noted that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand and implement all or part of the processes of the above embodiments, and equivalent changes made according to the claims of this application still fall within the scope of this application.

Claims

1. An intelligent power distribution system integrating a low-voltage battery management system (BMS), comprising a BMS control unit (1) and a low-voltage battery (2), a DC-DC converter (3), and a multi-channel power distribution module (4) communicatively connected to the BMS control unit (1), wherein the BMS control unit (1) comprises a main control chip (11) and a cell group voltage sampling circuit (12), a cell group current sampling circuit (13), a cell group temperature sampling circuit (14), and an active balancing circuit (15) electrically connected to the main control chip (11), wherein the low-voltage battery (2) has m cell groups; characterized in that: The DC-DC conversion unit (3) includes m bidirectional DC-DC converters (31). The input terminals of the m bidirectional DC-DC converters (31) are electrically connected to the m battery cell groups, and the output terminals are electrically connected to the input terminals of the multi-channel power distribution module (4). The multiple output terminals of the multi-channel power distribution module (4) are electrically connected to multiple low-voltage load modules. The main control chip (11) can control the m bidirectional DC-DC converters (31) and the multi-channel power distribution module (4) to connect any low-voltage load module to any battery cell group.

2. A smart power distribution method integrating a low-voltage battery management system (BMS), characterized in that, The method using the intelligent power distribution system as described in claim 1 includes: Obtain the temperature, voltage, SOC, SOH of each cell group, and the real-time power requirements of each low-voltage load module; Based on the SOC and SOH of each cell group, determine the power distribution weight of each cell group. Based on the power distribution weight of each battery cell group and the real-time power demand of each low-voltage load module, the power distribution of each battery cell group is determined. Based on the voltage and power distribution of each cell group, the theoretical discharge current of each cell group is determined. Based on the SOH, rated discharge rate, and rated capacity of each cell group, determine the maximum allowable discharge current of each cell group; The minimum value between the theoretical discharge current and the maximum allowable discharge current of each cell group is taken as the final discharge current of each cell group and sent to the corresponding bidirectional DC-DC converter (31).

3. The intelligent power distribution method integrating a low-voltage battery management system according to claim 2, characterized in that, Methods for determining the power distribution weights of each battery cell group include: Using the formula: Calculate the discharge SOC equalization weight of the i-th cell group. Where k represents the preset first acceleration factor, k≥1; Using the formula: Calculate the optimal weights for the discharge SOH of the i-th cell group. Where p represents the preset second acceleration factor, p≥1; Using the formula: The power distribution weight of the i-th cell group is calculated. .

4. The intelligent power distribution method for integrating a low-voltage battery management system according to claim 2, characterized in that: The method for determining the power distribution of each battery cell group is as follows: Using the formula: The power distribution of the i-th cell group is calculated. ;in, This represents the sum of the real-time power requirements of each low-voltage load module, where i takes all integer values ​​from 1 to m. The method for determining the theoretical discharge current of each cell group is as follows: Using the formula: The theoretical discharge current of the i-th cell group is calculated. ;in, This represents the voltage of the i-th cell group; Methods for determining the maximum allowable discharge current of each cell group include: Using the formula: Calculate the maximum allowable discharge rate of the i-th cell group. ;in, This indicates the rated discharge rate of each cell group. Indicates about an increasing function, ; Using the formula: The maximum allowable discharge current of the i-th cell group is calculated. ;in, This indicates the rated capacity of each battery cell pack.

5. The intelligent power distribution method for integrating a low-voltage battery management system according to claim 2, characterized in that: If the total power of the low-voltage battery is less than the sum of the real-time power requirements of each low-voltage load module, then the low-priority low-voltage load modules will be disconnected in the order of preset low-priority to high-priority.

6. The intelligent power distribution method integrating a low-voltage battery management system according to claim 2, characterized in that: During the discharge process of each cell group, when the SOC of a certain cell group is less than or equal to the preset discharge prohibition SOC threshold, the cell group is stopped from discharging.

7. The intelligent power distribution method integrating a low-voltage battery management system according to claim 2, characterized in that, During the low-voltage battery charging phase, the charging current of each cell group is obtained using the following method: Obtain the temperature, voltage, SOC, SOH, and total charging current of the low-voltage battery for each cell group; Based on the SOC and SOH of each cell group, determine the charging current allocation weight of each cell group. Based on the charging current allocation weight of each cell group and the total charging current of the low-voltage battery, the theoretical charging current of each cell group is determined. Based on the temperature and SOH of each cell group, determine the maximum allowable charging current of each cell group; The minimum value between the theoretical charging current and the maximum allowable charging current of each cell group is taken as the final charging current of each cell group and sent to the corresponding bidirectional DC-DC converter (31).

8. The intelligent power distribution method integrating a low-voltage battery management system according to claim 7, characterized in that: Methods for determining the charging current allocation weights for each cell group include: Using the formula: Calculate the charging SOC equalization weight of the i-th cell group. Where k represents the preset first acceleration factor, k≥1; Using the formula: Calculate the optimal weights for the state of charge (SOH) of the i-th cell group. Where p represents the preset second acceleration factor, p≥1; Using the formula: The charging current allocation weight of the i-th cell group is calculated. ; The method for determining the theoretical charging current of each cell group is as follows: Using the formula: The theoretical charging current of the i-th cell group is calculated. i takes all integers from 1 to m in sequence; The method for determining the maximum allowable charging current of each cell group is as follows: Based on the temperature and SOH of the i-th cell group, the maximum allowable charging current of the i-th cell group is obtained by querying the preset correspondence table between temperature, SOH and maximum allowable charging current.

9. The intelligent power distribution method for integrating a low-voltage battery management system according to any one of claims 2 to 7, characterized in that: The charge / discharge voltage window for the i-th cell group is: ;in, This represents the discharge cutoff voltage of the i-th cell group after compensation. This represents the charging cutoff voltage of the i-th cell group after compensation, where i takes all integers from 1 to m. The discharge cutoff voltage The method of obtaining it is as follows: Using the formula: Calculate the theoretical discharge cutoff voltage of the i-th cell group. ;in, This indicates the preset reference standard SOH. Indicates the default and The corresponding discharge cutoff reference voltage, This represents the preset discharge lower limit compensation coefficient. ; Using the formula: The discharge cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the maximum value. This indicates the preset lower limit of the absolute voltage for cell chemical safety; The charging cutoff voltage The method of obtaining it is as follows: Using the formula: Calculate the theoretical charging cutoff voltage of the i-th cell group. ;in, Indicates the default and The corresponding charging cutoff reference voltage, This represents the preset charging upper limit compensation coefficient. ; Using the formula: The charging cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the minimum value. This indicates the preset upper limit of the absolute voltage for cell chemical safety.

10. The intelligent power distribution method for integrating a low-voltage battery management system according to any one of claims 2 to 7, characterized in that: The charge / discharge voltage window for the i-th cell group is: ;in, This represents the discharge cutoff voltage of the i-th cell group after compensation. This represents the charging cutoff voltage of the i-th cell group after compensation, where i takes all integers from 1 to m. The discharge cutoff voltage The method of obtaining it is as follows: Using the formula: Calculate the theoretical discharge cutoff voltage of the i-th cell group. ;in, This indicates the preset reference standard SOH. Indicates the default and The corresponding discharge cutoff reference voltage, This represents the preset discharge lower limit compensation coefficient. , This represents the preset third acceleration factor. ; Using the formula: The discharge cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the maximum value. This indicates the preset lower limit of the absolute voltage for cell chemical safety; The charging cutoff voltage The method of obtaining it is as follows: Using the formula: Calculate the theoretical charging cutoff voltage of the i-th cell group. ;in, Indicates the default and The corresponding charging cutoff reference voltage, This represents the preset charging upper limit compensation coefficient. ; Using the formula: The charging cutoff voltage of the i-th cell group after compensation is calculated. ;in, This represents the function that takes the minimum value. This indicates the preset upper limit of the absolute voltage for cell chemical safety.

11. The intelligent power distribution method integrating a low-voltage battery management system according to claim 9, characterized in that: During the charging process of each cell group, when the voltage of a certain cell group is greater than or equal to the charging cutoff voltage of that cell group after compensation, the charging of that cell group will be stopped.

12. A vehicle, characterized in that: The intelligent power distribution system includes the integrated low-voltage battery management system as described in claim 1.

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