A dual-core battery range extending method, system and vehicle

Abstract

The application provides a dual-core battery range extending method, system and vehicle, and belongs to the technical field of electric vehicle power batteries, and comprises the following steps: connecting a main battery and a secondary battery to a rear-drive MCU of an electric vehicle in a parallel mode through a bidirectional DC / DC inverter, directly electrically connecting the main battery and the rear-drive MCU, and electrically connecting the secondary battery and the rear-drive MCU through the bidirectional DC / DC inverter; preferentially using the main battery during discharging, starting secondary battery discharging when the state of charge of the main battery decreases to a first preset threshold, and dynamically adjusting the bidirectional DC / DC inverter according to the state of charge of the main battery to make the secondary battery charge the main battery or supply power to the main battery together; preferentially charging the secondary battery to a second preset threshold and then charging the main battery during charging. The application cooperatively optimizes the energy density and power performance of the vehicle-mounted battery.

Description

Technical Field

[0001] This invention belongs to the field of electric vehicle power battery technology, and particularly relates to a dual-core battery range extender method, system and vehicle. Background Technology

[0002] The power battery system of electric vehicles is a core component affecting the vehicle's range, power performance, and lifespan. Currently, power batteries mainly use liquid lithium-ion batteries, which have good power characteristics and long lifespan. In hybrid or pure electric vehicles, due to space constraints, it is difficult to achieve large-capacity configurations using only liquid lithium-ion batteries, resulting in limited pure electric range. To overcome the energy density bottleneck, semi-solid-state batteries and solid-state batteries have gradually become research hotspots, with significantly higher energy densities than liquid lithium-ion batteries and greater safety.

[0003] However, the cycle life of semi-solid and solid batteries is typically only 1,000-1,500 cycles, with a low discharge rate, which cannot meet the requirements of electric vehicles for high power output and long cycle life. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this invention proposes a dual-core battery range extender method, system, and vehicle to solve the technical problem that a single battery type in the prior art cannot simultaneously meet the requirements of large capacity, high power, and long cycle life.

[0005] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: In a first aspect, the present invention discloses a dual-core battery range extension method, comprising: The main battery and the auxiliary battery are connected in parallel to the rear drive MCU of the electric vehicle through a bidirectional DC / DC inverter. The bidirectional DC / DC inverter performs charge and discharge voltage conversion on the auxiliary battery so that the voltage of the auxiliary battery matches the voltage of the main battery. During the discharge process, the main battery is used to discharge first; when the state of charge of the main battery drops to a first preset threshold, the bidirectional DC / DC inverter is started, the auxiliary battery begins to discharge, and the bidirectional DC / DC inverter dynamically adjusts the charging power according to the state of charge of the main battery, so that the auxiliary battery charges the main battery or supplies power to the rear drive MCU together with the main battery. During the charging process, the auxiliary battery is charged to a second preset threshold first, and then the main battery is charged.

[0006] In a further technical solution, the main battery is directly electrically connected to the rear-drive MCU, and the auxiliary battery is electrically connected to the rear-drive MCU through the bidirectional DC / DC inverter.

[0007] In a further technical solution, the main battery is a liquid lithium-ion battery, and the auxiliary battery is a semi-solid battery or a solid battery.

[0008] A further technical solution involves the bidirectional DC / DC inverter employing a proportional control algorithm for dynamic power adjustment when the secondary battery charges the primary battery. Specifically, the charging power command is calculated based on the deviation between the primary battery's state of charge and the first preset threshold.

[0009] Where K is the proportionality coefficient. The upper limit of the first preset threshold. The real-time state of charge of the main battery.

[0010] Further technical solutions include adjusting energy distribution strategies based on driving conditions: The energy distribution strategy is adjusted according to the driving mileage. When the single driving mileage is less than the preset mileage threshold, the main battery is used to discharge; when the single driving mileage is greater than or equal to the preset mileage threshold, the main battery is first used to discharge to the first preset threshold, and then the auxiliary battery is activated to extend the range.

[0011] A further technical solution employs a dynamic linkage mechanism between SOH assessment and SOC threshold for the first preset threshold and the second preset threshold. Specifically: Every time a certain number of charge-discharge cycles are completed or the cumulative mileage reaches a threshold, a SOH assessment is triggered and the storage is updated. When the SOH of the auxiliary battery is below 80%, a tiered adjustment strategy is adopted. When the SOH of the auxiliary battery is between 70% and 80%, the second preset threshold is lowered by 5%; when the SOH of the auxiliary battery is between 60% and 70%, the second preset threshold is lowered by 10%; when the SOH of the auxiliary battery is below 60%, the second preset threshold is lowered by 15%, and a suggestion to replace the auxiliary battery is issued to the user. When the SOH of the main battery is below 80%, a tiered adjustment strategy is adopted. When the SOH of the main battery is between 70% and 80%, the first preset threshold is increased by 5%; when the SOH of the main battery is between 60% and 70%, the first preset threshold is increased by 10%; when the SOH of the main battery is below 60%, the first preset threshold is increased by 15%, and a suggestion to replace the main battery is issued to the user.

[0012] Secondly, the present invention discloses a dual-core battery range extender system, comprising: A main battery; a secondary battery; a bidirectional DC / DC inverter connecting the main battery and the secondary battery for charging and discharging voltage conversion of the secondary battery; a rear-drive MCU, with the main battery directly electrically connected to the rear-drive MCU and the secondary battery electrically connected to the rear-drive MCU through the bidirectional DC / DC inverter; a fast and slow charging interface, with the main battery directly electrically connected to the fast and slow charging interface and the secondary battery electrically connected to the fast and slow charging interface through the bidirectional DC / DC inverter; and a controller configured to execute the aforementioned dual-core battery range extension method.

[0013] Thirdly, the present invention discloses a vehicle including a memory and a processor, and computer instructions stored in the memory and running on the processor, wherein the computer instructions, when executed by the processor, complete the steps of the above-described dual-core battery range extender method.

[0014] Fourthly, the present invention discloses a computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the steps of the above-described dual-core battery range extension method.

[0015] Fifthly, the present invention discloses a computer program product comprising executable instructions stored in a computer-readable storage medium; wherein, when the vehicle's processor reads and executes the executable instructions from the computer-readable storage medium, it completes the steps of the aforementioned dual-core battery range extender method.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a dual-core architecture of liquid lithium-ion batteries and semi-solid / solid batteries. It achieves parallel connection and voltage matching of main and auxiliary batteries through a bidirectional high-power DC / DC inverter. Based on the SOC discharge / charge priority control strategy, it synergistically leverages the high power and long lifespan characteristics of liquid batteries and the high energy density and high safety characteristics of solid batteries. Furthermore, it adapts to different operating conditions through a differentiated energy allocation strategy, thereby achieving synergistic optimization of energy density and power performance, extension of cycle life, and improvement of system reliability.

[0017] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a schematic diagram of the dual-core battery range extender system described in Embodiment 2 of the present invention. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0022] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0023] While liquid lithium-ion batteries offer good power performance and cycle life, their limited energy density makes it difficult to achieve large-capacity configurations in vehicles with limited space. Semi-solid and solid-state batteries, although possessing high energy density, suffer from poor cycle life and charge / discharge rate performance, failing to meet the dual demands of electric vehicles for high-rate discharge and long cycle life. Therefore, there is an urgent need for a power battery system solution that can synergistically leverage the advantages of different battery types while balancing energy density and power performance.

[0024] Example 1 In one or more embodiments, a dual-core battery range extender method is disclosed, comprising: The main battery and the auxiliary battery are connected in parallel to the rear drive MCU of the electric vehicle through a bidirectional DC / DC inverter. The main battery is directly electrically connected to the rear drive MCU, and the auxiliary battery is electrically connected to the rear drive MCU through the bidirectional DC / DC inverter. The bidirectional DC / DC inverter performs charging and discharging voltage conversion on the auxiliary battery so that the voltage of the auxiliary battery matches the voltage of the main battery. During the discharge process, the controller prioritizes the discharge of the main battery; when the state of charge of the main battery drops to a first preset threshold, the controller controls the bidirectional DC / DC inverter to start, and the auxiliary battery begins to discharge. The bidirectional DC / DC inverter dynamically adjusts the charging power according to the state of charge of the main battery, so that the auxiliary battery charges the main battery or supplies power to the rear drive MCU together with the main battery. During the charging process, the controller prioritizes charging the auxiliary battery to a second preset threshold before charging the main battery.

[0025] This embodiment employs a dual-core architecture with a main battery and a secondary battery, achieving complementary advantages of different battery types. The main battery is directly connected to the drive MCU, undertaking high-power output tasks; the secondary battery is connected via a DC / DC inverter, serving as a range-extending energy reserve. During discharge, the main battery is prioritized to fully utilize its high power and long lifespan characteristics. When the main battery's state of charge drops to a first preset threshold, the secondary battery initiates range extension. At this time, the DC / DC inverter dynamically adjusts the charging power according to the main battery's state of charge: the lower the main battery's state of charge, the higher the charging power, quickly replenishing the main battery's charge; when the main battery's state of charge approaches the upper limit of the first preset threshold, the charging power gradually decreases to avoid overcharging. During charging, the secondary battery is prioritized for charging to a second preset threshold to ensure sufficient range-extending energy reserve before charging the main battery, until both batteries are fully charged.

[0026] Furthermore, the main battery is a liquid lithium-ion battery, and the auxiliary battery is a semi-solid-state battery or a solid-state battery. Liquid lithium-ion batteries have good power characteristics and long lifespan, making them suitable for high-power output tasks; semi-solid-state or solid-state batteries have high energy density and high safety characteristics, making them suitable as range-extending energy storage sources.

[0027] Preferably, the main battery has an energy density of 160-300 Wh / kg, a cycle life of ≥2000 cycles, and a discharge rate of ≥3C; the auxiliary battery has an energy density of 300-600 Wh / kg, a cycle life of 1000-1500 cycles, and a discharge rate of ≤1C. This parameter configuration ensures that the main battery can provide high power output and long cycle life, while the auxiliary battery provides high energy density range extension reserves. Although the energy density of the main battery is lower than that of the auxiliary battery, its high discharge rate capability and long cycle life make it the main power supply unit; the high energy density of the auxiliary battery compensates for the insufficient power of the main battery.

[0028] Preferably, the first preset threshold is typically set to 20%-30%, and the second preset threshold is typically set to 80%-90%. The first preset threshold is set to ensure the main battery maintains high power output when its state of charge (SOC) is above 20%, while power degradation is significant when the SOC is below 20%. Therefore, setting it to 20%-30% ensures the main battery's power output while providing a reasonable start-up opportunity for the auxiliary battery's range extension. The second preset threshold is set to ensure that semi-solid-state or solid-state batteries have high charging efficiency when the SOC is below 90%, while charging speed decreases significantly and the risk of overcharging increases when the SOC is above 90%. Therefore, setting it to 80%-90% ensures sufficient range extension reserve energy for the auxiliary battery while avoiding battery performance degradation caused by overcharging.

[0029] Furthermore, when the secondary battery charges the main battery, the bidirectional DC / DC inverter uses a proportional control algorithm to dynamically adjust the power. Specifically, the charging power command is calculated based on the deviation between the state of charge of the main battery and the first preset threshold. The larger the deviation, the greater the charging power. When the deviation approaches zero, the charging power gradually decreases to zero.

[0030] Specifically, the charging power command is as follows:

[0031] Wherein, K is a proportionality coefficient, which is taken as 1000W / % in this embodiment. The upper limit of the first preset threshold. The real-time state of charge of the main battery.

[0032] For example, when the main battery's state of charge (SOC) is 20%, the charging power command is 1000 × (25% - 20%) = 5 kW; when the main battery's SOC is 23%, the charging power command is 1000 × (25% - 23%) = 2 kW. The upper limit of the charging power is limited by the rated power of the DC / DC inverter, typically 30 kW.

[0033] This embodiment achieves precise management of the main battery's state of charge (SOC) through dynamic power regulation control logic for charging the main battery from the secondary battery. When the main battery's SOC drops to a first preset threshold, the secondary battery initiates range extension. The DC / DC inverter dynamically adjusts the charging power based on the deviation between the main battery's SOC and the first preset threshold; the larger the deviation, the greater the charging power, and as the deviation approaches zero, the charging power gradually decreases to zero. This proportional control algorithm avoids over-discharging of the main battery while also preventing excessive temperature rise due to excessive charging power. The setting of the first and second preset thresholds ensures that the reasonable setting of the SOC target value balances battery life and performance. The main battery maintains high power output capability above the first preset threshold, while the secondary battery is prevented from overcharging below the second preset threshold.

[0034] In some embodiments, the system further includes adjusting the energy distribution strategy based on driving conditions: When the single driving mileage is less than a preset mileage threshold, the main battery is primarily used for discharge; when the single driving mileage is greater than or equal to the preset mileage threshold, the main battery is first used to discharge to the first preset threshold before the auxiliary battery is activated for range extension. The preset mileage threshold is typically set to 50km. For short-distance driving, in this embodiment, when the single driving mileage is <50km, the main battery is primarily used to reduce the frequency of auxiliary battery use and extend the cycle life of the auxiliary battery.

[0035] This embodiment achieves optimized energy management in different application scenarios by adjusting the energy distribution strategy according to driving conditions. For short-distance driving, the main battery is primarily used, reducing the frequency of auxiliary battery use and extending its cycle life. For long-distance driving, the main battery is used up to a first preset threshold before the auxiliary battery is activated to extend the range, fully leveraging the high energy density of solid-state batteries to achieve ultra-long driving range.

[0036] As a preferred embodiment, the energy distribution strategy is adjusted according to the ambient temperature. When the ambient temperature is below a preset temperature threshold, the main battery is used to discharge first, and the auxiliary battery reduces its output power or is shut down. The preset temperature threshold is usually set to 0°C. Under low-temperature conditions, the performance degradation of liquid lithium-ion batteries is less than that of semi-solid or solid batteries, so the main battery is used first.

[0037] Specifically, when the ambient temperature is below 0°C, the output power of the auxiliary battery is limited to 50%-70% of its rated power; when the ambient temperature is below -20°C, the auxiliary battery is deactivated, and the vehicle relies solely on the main battery for power. This strategy avoids the drawbacks of solid-state batteries, such as reduced ion mobility and limited discharge rate at low temperatures, ensuring the vehicle's power performance in low-temperature environments.

[0038] Furthermore, the main battery is directly connected to the fast and slow charging interfaces, and the fast and slow charging currents for the auxiliary battery are connected to the auxiliary battery through the bidirectional DC / DC inverter. The main battery can be charged independently via fast charging, while the auxiliary battery is charged through the DC / DC inverter, enabling flexible charging management of the dual-battery system. After the external fast and slow charging interfaces are connected, the controller prioritizes charging the auxiliary battery. When the auxiliary battery's state of charge reaches a second preset threshold, the controller switches the charging path and begins charging the main battery until both the main and auxiliary batteries are fully charged.

[0039] Preferably, the system further includes: a controller that determines battery faults by monitoring the voltage, current, and temperature anomalies of the main battery or the auxiliary battery. A battery fault is determined when a voltage deviation greater than 10%, a temperature higher than 60°C, or an internal resistance increase exceeding 50% is detected. When a battery fault is detected, the controller disconnects the faulty battery from the bidirectional DC / DC inverter, allowing the other battery to supply power independently. This redundant power supply design improves system reliability and safety. When either battery fails, the other battery can provide independent power, preventing the entire vehicle from breaking down. The controller monitors the voltage, current, and temperature data of the main and auxiliary batteries in real time, and collects sensor signals via the CAN bus. When a voltage deviation greater than 10% relative to the normal voltage range, a temperature higher than 60°C, or an internal resistance increase exceeding 50% relative to the initial internal resistance is detected, a battery fault is determined, and the electrical connection between the faulty battery and the DC / DC inverter is immediately disconnected, switching to an independent power supply mode for the other battery.

[0040] As one implementation method, a dynamic linkage mechanism between SOH assessment and SOC threshold is adopted for the first preset threshold and the second preset threshold of SOC.

[0041] SOH evaluation method: The controller collects three signals—terminal voltage, charging and discharging current, and battery temperature—from the main and auxiliary batteries via the CAN bus at a sampling frequency of 10Hz.

[0042] The internal resistance is calculated using the current pulse method. At each charge / discharge switching moment (current sudden change), the voltage sudden change ΔU and the current sudden change ΔI are recorded, and the DC internal resistance is calculated as follows: , The DC internal resistance is compared with the initial internal resistance R0 to calculate the internal resistance growth rate. for:

[0043] The capacity calculation uses the ampere-hour integration method, which integrates the current over time during each complete charge-discharge cycle to obtain the actual discharge capacity Q. actual Compared with the initial capacity Q0, the capacity retention rate wei is calculated.

[0044] The comprehensive calculation formula for SOH is:

[0045] The more severe of the two factors, internal resistance decay and capacity decay, is taken as the criterion for determining SOH.

[0046] The evaluation is triggered every 100 charge-discharge cycles or when the cumulative mileage reaches 5000 kilometers, triggering a SOH evaluation and updating the stored data. The SOH evaluation results are stored in the controller's non-volatile EEPROM, which is not lost after power failure, and the historical SOH value is directly read as the initial reference upon the next power-on.

[0047] Treatment when the SOH of secondary battery B is below 80%: A tiered adjustment strategy is adopted: when SOH is between 70% and 80%, the second preset threshold is lowered by 5%; when SOH is between 60% and 70%, the second preset threshold is lowered by 10%; when SOH is below 60%, the second preset threshold is lowered by 15%, and at the same time, a prompt is issued to the user to replace the auxiliary battery B.

[0048] The physical basis for the adjustment is that after solid-state or semi-solid-state batteries age, their charging acceptance in the high SOC range decreases significantly. Preferably, the high SOC range is defined as an SOC greater than 80%. Continuous high SOC charging accelerates lattice distortion of the cathode material. By lowering the charging cutoff SOC, the charging range is limited to the low SOC region with higher electrochemical activity, which can effectively slow down the capacity decay rate. Taking a 50kWh secondary battery B as an example, when the second preset threshold is reduced from 85% to 78%, the available range extension capacity decreases from 42.5kWh to 39kWh, reducing the driving range by approximately 20 kilometers. The controller simultaneously updates the estimated driving range and notifies the instrument panel display.

[0049] Handling when the SOH of main cell A is below 80%: A tiered adjustment strategy is adopted: when the SOH is between 70% and 80%, the first preset threshold is increased by 5%; when the SOH is between 60% and 70%, the first preset threshold is increased by 10%; when the SOH is below 60%, the first preset threshold is increased by 15%, and a prompt to replace the main battery A is issued to the user.

[0050] The physical basis for the adjustment is that after the liquid lithium-ion battery ages, the internal resistance in the low SOC range increases significantly. Preferably, the low SOC range is less than 20%. Deep discharge leads to accelerated loss of active lithium on the negative electrode. By increasing the discharge cutoff SOC, the main battery A is prevented from entering the high internal resistance deep discharge range, which can effectively delay capacity decay. After the first preset threshold is increased, the range extension start-up timing of the auxiliary battery B is advanced accordingly. While updating the first preset threshold, the controller simultaneously updates the range extension trigger judgment logic of the auxiliary battery B to ensure the overall consistency of the energy management strategy.

[0051] Dual-cell SOH imbalance protection: Imbalance is determined by the absolute value of the difference between the main and auxiliary cells' SOH values, calculated as follows: SOH A Reduce SOH B The absolute value of the difference is used to trigger imbalance protection when the difference exceeds 20%.

[0052] Furthermore, power limiting is implemented in two steps: The first step is to limit the maximum discharge power of batteries with lower State of Harmony (SOH) to 70% of their rated power. The second step is to prioritize scheduling batteries with higher SOH to handle high power demands in each energy allocation decision, while batteries with lower SOH only handle the basic load.

[0053] Preferably, regarding the frequency of use adjustment, under short-distance operating conditions, if the SOH of the auxiliary battery B is significantly lower than that of the main battery A, and the difference is greater than a preset threshold, the controller further increases the range extension start threshold of the auxiliary battery B, that is, the auxiliary battery B intervenes later, reducing the actual number of times the auxiliary battery B is used.

[0054] The user alert mechanism is as follows: when the SOH is below 60% or the SOH difference exceeds 30%, the controller sends a battery health warning command to the instrument panel controller via the CAN bus. The instrument panel displays the corresponding battery health status icon, which can be either a yellow warning or a red alarm. After the trip is over, maintenance suggestions are pushed to the vehicle system.

[0055] Existing fixed SOC threshold strategies cannot detect battery aging, causing aged batteries to continue operating with new battery parameters, accelerating degradation. This embodiment achieves adaptive energy management throughout the entire battery lifecycle by dynamically linking real-time SOH assessment with the SOC threshold. It dynamically adjusts the charge and discharge boundaries based on the actual battery health condition, maximizing battery lifespan while ensuring system performance.

[0056] Example 2 In one or more embodiments, a dual-core battery range extender system is disclosed, such as Figure 1 As shown, the system specifically includes: a main battery; a secondary battery; a bidirectional high-power DC / DC inverter connected to the main battery and the secondary battery for charging and discharging voltage conversion of the secondary battery; a rear-drive MCU, with the main battery directly electrically connected to the rear-drive MCU and the secondary battery electrically connected to the rear-drive MCU through the bidirectional high-power DC / DC inverter; a fast and slow charging interface, with the main battery directly electrically connected to the fast and slow charging interface and the secondary battery electrically connected to the fast and slow charging interface through the bidirectional high-power DC / DC inverter; and a controller configured to execute the aforementioned dual-core battery range extension method.

[0057] Furthermore, the main battery is placed at the bottom of the electric vehicle, while the auxiliary battery is placed in the trunk. The main battery's placement at the bottom utilizes the space to house a large-capacity battery pack, providing the vehicle with primary electrical power. The auxiliary battery, located in the trunk, serves as a range-extending energy reserve. This differentiated spatial layout caters to the functional roles of the different batteries. Placing the main battery at the bottom helps lower the vehicle's center of gravity, improving handling stability; placing the auxiliary battery in the trunk facilitates maintenance and replacement, while also enhancing its safety.

[0058] Preferably, the bidirectional high-power DC / DC inverter performs voltage conversion on the auxiliary battery, matching its voltage with that of the main battery. The main battery and the auxiliary battery form a parallel power supply topology through the bidirectional high-power DC / DC inverter. The DC / DC inverter achieves voltage range matching between the auxiliary battery and the main battery, supporting bidirectional energy flow. The parallel power supply topology of the main battery and auxiliary battery allows them to jointly power the downstream MCU, or for the auxiliary battery to charge the main battery, enabling flexible energy management.

[0059] Specifically, the bidirectional high-power DC / DC inverter adopts either a bidirectional Buck-Boost topology or an LLC resonant topology. The bidirectional Buck-Boost topology is simple in structure and low in cost, making it suitable for economy vehicles; the LLC resonant topology is more efficient and suitable for long-term high-power charging and discharging scenarios and high-end vehicles. The bidirectional Buck-Boost topology includes components such as switching transistors, freewheeling diodes, inductors, and capacitors, and voltage rise and fall are achieved by adjusting the duty cycle of the switching transistors; the LLC resonant topology includes components such as resonant inductors, resonant capacitors, transformers, and full-bridge rectifier circuits, and voltage regulation is achieved by adjusting the switching frequency.

[0060] In some embodiments, the controller communicates with the main battery, the auxiliary battery, the bidirectional high-power DC / DC inverter, and the rear-drive MCU via a CAN bus. The CAN bus is a commonly used communication protocol in automotive electronic systems, offering high reliability, real-time performance, and interference resistance. The controller uses the CAN bus to collect real-time data on the state of charge, voltage, current, and temperature of the main and auxiliary batteries, sending charging and discharging power commands to the DC / DC inverter and torque commands to the rear-drive MCU, thereby achieving coordinated control of the vehicle's energy management.

[0061] As a preferred embodiment, the main battery and the auxiliary battery are respectively equipped with a voltage sensor, a current sensor, and a temperature sensor. The voltage sensor is used to monitor the battery terminal voltage, the current sensor is used to monitor the charging and discharging current, and the temperature sensor is used to monitor the battery temperature. The sensor sampling frequency is typically ≥10Hz to ensure that the controller can acquire battery status data in real time. The controller calculates the battery state of charge based on the sensor data, determines the battery health status, executes charging and discharging control strategies, and achieves precise energy management.

[0062] Furthermore, the bidirectional DC / DC inverter includes: an input terminal connected to a secondary battery; an output terminal connected to a main battery or a drive MCU; and a bidirectional power conversion circuit to realize voltage rise / fall and bidirectional energy flow between the input terminal and the output terminal.

[0063] In this embodiment, the following range extension method is executed according to the above-described dual-core battery range extender system: The main battery and the auxiliary battery are connected in parallel to the rear drive MCU of the electric vehicle through a bidirectional DC / DC inverter. The main battery is directly electrically connected to the rear drive MCU, and the auxiliary battery is electrically connected to the rear drive MCU through the bidirectional DC / DC inverter. The bidirectional DC / DC inverter performs charging and discharging voltage conversion on the auxiliary battery so that the voltage of the auxiliary battery matches the voltage of the main battery. During the discharge process, the controller prioritizes the discharge of the main battery; when the state of charge of the main battery drops to a first preset threshold, the controller controls the bidirectional DC / DC inverter to start, and the auxiliary battery begins to discharge. The bidirectional DC / DC inverter dynamically adjusts the charging power according to the state of charge of the main battery, so that the auxiliary battery charges the main battery or supplies power to the rear drive MCU together with the main battery. During the charging process, the controller prioritizes charging the auxiliary battery to a second preset threshold before charging the main battery.

[0064] This embodiment employs a dual-core architecture with a main battery and a secondary battery, achieving complementary advantages of different battery types. The main battery is directly connected to the drive MCU, undertaking high-power output tasks; the secondary battery is connected via a DC / DC inverter, serving as a range-extending energy reserve. During discharge, the main battery is prioritized to fully utilize its high power and long lifespan characteristics. When the main battery's state of charge drops to a first preset threshold, the secondary battery initiates range extension. At this time, the DC / DC inverter dynamically adjusts the charging power according to the main battery's state of charge: the lower the main battery's state of charge, the higher the charging power, quickly replenishing the main battery's charge; when the main battery's state of charge approaches the upper limit of the first preset threshold, the charging power gradually decreases to avoid overcharging. During charging, the secondary battery is prioritized for charging to a second preset threshold to ensure sufficient range-extending energy reserve before charging the main battery, until both batteries are fully charged.

[0065] Furthermore, the main battery is a liquid lithium-ion battery, and the auxiliary battery is a semi-solid-state battery or a solid-state battery. Liquid lithium-ion batteries have good power characteristics and long lifespan, making them suitable for high-power output tasks; semi-solid-state or solid-state batteries have high energy density and high safety characteristics, making them suitable as range-extending energy storage sources.

[0066] Preferably, the main battery has an energy density of 160-300 Wh / kg, a cycle life of ≥2000 cycles, and a discharge rate of ≥3C; the auxiliary battery has an energy density of 300-600 Wh / kg, a cycle life of 1000-1500 cycles, and a discharge rate of ≤1C. This parameter configuration ensures that the main battery can provide high power output and long cycle life, while the auxiliary battery provides high energy density range extension reserves. Although the energy density of the main battery is lower than that of the auxiliary battery, its high discharge rate capability and long cycle life make it the main power supply unit; the high energy density of the auxiliary battery compensates for the insufficient power of the main battery.

[0067] Preferably, the first preset threshold is typically set to 20%-30%, and the second preset threshold is typically set to 80%-90%. The first preset threshold is set to ensure the main battery maintains high power output when its state of charge (SOC) is above 20%, while power degradation is significant when the SOC is below 20%. Therefore, setting it to 20%-30% ensures the main battery's power output while providing a reasonable start-up opportunity for the auxiliary battery's range extension. The second preset threshold is set to ensure that semi-solid-state or solid-state batteries have high charging efficiency when the SOC is below 90%, while charging speed decreases significantly and the risk of overcharging increases when the SOC is above 90%. Therefore, setting it to 80%-90% ensures sufficient range extension reserve energy for the auxiliary battery while avoiding battery performance degradation caused by overcharging.

[0068] Furthermore, when the secondary battery charges the main battery, the bidirectional DC / DC inverter uses a proportional control algorithm to dynamically adjust the power. Specifically, the charging power command is calculated based on the deviation between the state of charge of the main battery and the first preset threshold. The larger the deviation, the greater the charging power. When the deviation approaches zero, the charging power gradually decreases to zero.

[0069] Specifically, the charging power command is as follows:

[0070] Wherein, K is a proportionality coefficient, which is taken as 1000W / % in this embodiment. The upper limit of the first preset threshold. The real-time state of charge of the main battery.

[0071] For example, when the main battery's state of charge (SOC) is 20%, the charging power command is 1000 × (25% - 20%) = 5 kW; when the main battery's SOC is 23%, the charging power command is 1000 × (25% - 23%) = 2 kW. The upper limit of the charging power is limited by the rated power of the DC / DC inverter, typically 30 kW.

[0072] In some embodiments, the system further includes adjusting the energy distribution strategy based on driving conditions: When the single driving mileage is less than a preset mileage threshold, the main battery is primarily used for discharge; when the single driving mileage is greater than or equal to the preset mileage threshold, the main battery is first used to discharge to the first preset threshold before the auxiliary battery is activated for range extension. The preset mileage threshold is typically set to 50km. For short-distance driving, in this embodiment, when the single driving mileage is <50km, the main battery is primarily used to reduce the frequency of auxiliary battery use and extend the cycle life of the auxiliary battery.

[0073] As a preferred embodiment, the energy distribution strategy is adjusted according to the ambient temperature. When the ambient temperature is below a preset temperature threshold, the main battery is used to discharge first, and the auxiliary battery reduces its output power or is shut down. The preset temperature threshold is usually set to 0°C. Under low-temperature conditions, the performance degradation of liquid lithium-ion batteries is less than that of semi-solid or solid batteries, so the main battery is used first.

[0074] Specifically, when the ambient temperature is below 0°C, the output power of the auxiliary battery is limited to 50%-70% of its rated power; when the ambient temperature is below -20°C, the auxiliary battery is deactivated, and the vehicle relies solely on the main battery for power. This strategy avoids the drawbacks of solid-state batteries, such as reduced ion mobility and limited discharge rate at low temperatures, ensuring the vehicle's power performance in low-temperature environments.

[0075] Furthermore, the main battery is directly connected to the fast and slow charging interfaces, and the fast and slow charging currents for the auxiliary battery are connected to the auxiliary battery through the bidirectional DC / DC inverter. The main battery can be charged independently via fast charging, while the auxiliary battery is charged through the DC / DC inverter, enabling flexible charging management of the dual-battery system. After the external fast and slow charging interfaces are connected, the controller prioritizes charging the auxiliary battery. When the auxiliary battery's state of charge reaches a second preset threshold, the controller switches the charging path and begins charging the main battery until both the main and auxiliary batteries are fully charged.

[0076] Preferably, the system further includes: a controller that determines battery faults by monitoring the voltage, current, and temperature anomalies of the main battery or the auxiliary battery. A battery fault is determined when a voltage deviation greater than 10%, a temperature higher than 60°C, or an internal resistance increase exceeding 50% is detected. When a battery fault is detected, the controller disconnects the faulty battery from the bidirectional DC / DC inverter, allowing the other battery to supply power independently. This redundant power supply design improves system reliability and safety. When either battery fails, the other battery can provide independent power, preventing the entire vehicle from breaking down. The controller monitors the voltage, current, and temperature data of the main and auxiliary batteries in real time, and collects sensor signals via the CAN bus. When a voltage deviation greater than 10% relative to the normal voltage range, a temperature higher than 60°C, or an internal resistance increase exceeding 50% relative to the initial internal resistance is detected, a battery fault is determined, and the electrical connection between the faulty battery and the DC / DC inverter is immediately disconnected, switching to an independent power supply mode for the other battery.

[0077] As one implementation method, a dynamic linkage mechanism between SOH assessment and SOC threshold is adopted for the first preset threshold and the second preset threshold of SOC.

[0078] SOH evaluation method: The controller collects three signals—terminal voltage, charging and discharging current, and battery temperature—from the main and auxiliary batteries via the CAN bus at a sampling frequency of 10Hz.

[0079] The internal resistance is calculated using the current pulse method. At each charge / discharge switching moment (current sudden change), the voltage sudden change ΔU and the current sudden change ΔI are recorded, and the DC internal resistance is calculated as follows: , The DC internal resistance is compared with the initial internal resistance R0 to calculate the internal resistance growth rate. for:

[0080] The capacity calculation uses the ampere-hour integration method, which integrates the current over time during each complete charge-discharge cycle to obtain the actual discharge capacity Q. actual Compared with the initial capacity Q0, the capacity retention rate wei is calculated.

[0081] The comprehensive calculation formula for SOH is:

[0082] The more severe of the two factors, internal resistance decay and capacity decay, is taken as the criterion for determining SOH.

[0083] The evaluation is triggered every 100 charge-discharge cycles or when the cumulative mileage reaches 5000 kilometers, triggering a SOH evaluation and updating the stored data. The SOH evaluation results are stored in the controller's non-volatile EEPROM, which is not lost after power failure, and the historical SOH value is directly read as the initial reference upon the next power-on.

[0084] Treatment when the SOH of secondary battery B is below 80%: A tiered adjustment strategy is adopted: when SOH is between 70% and 80%, the second preset threshold is lowered by 5%; when SOH is between 60% and 70%, the second preset threshold is lowered by 10%; when SOH is below 60%, the second preset threshold is lowered by 15%, and at the same time, a prompt is issued to the user to replace the auxiliary battery B.

[0085] The physical basis for the adjustment is that after solid-state or semi-solid-state batteries age, their charging acceptance in the high SOC range decreases significantly. Preferably, the high SOC range is defined as an SOC greater than 80%. Continuous high SOC charging accelerates lattice distortion of the cathode material. By lowering the charging cutoff SOC, the charging range is limited to the low SOC region with higher electrochemical activity, which can effectively slow down the capacity decay rate. Taking a 50kWh secondary battery B as an example, when the second preset threshold is reduced from 85% to 78%, the available range extension capacity decreases from 42.5kWh to 39kWh, reducing the driving range by approximately 20 kilometers. The controller simultaneously updates the estimated driving range and notifies the instrument panel display.

[0086] Handling when the SOH of main cell A is below 80%: A tiered adjustment strategy is adopted: when the SOH is between 70% and 80%, the first preset threshold is increased by 5%; when the SOH is between 60% and 70%, the first preset threshold is increased by 10%; when the SOH is below 60%, the first preset threshold is increased by 15%, and a prompt to replace the main battery A is issued to the user.

[0087] The physical basis for the adjustment is that after the liquid lithium-ion battery ages, the internal resistance in the low SOC range increases significantly. Preferably, the low SOC range is less than 20%. Deep discharge leads to accelerated loss of active lithium on the negative electrode. By increasing the discharge cutoff SOC, the main battery A is prevented from entering the high internal resistance deep discharge range, which can effectively delay capacity decay. After the first preset threshold is increased, the range extension start-up timing of the auxiliary battery B is advanced accordingly. While updating the first preset threshold, the controller simultaneously updates the range extension trigger judgment logic of the auxiliary battery B to ensure the overall consistency of the energy management strategy.

[0088] Dual-cell SOH imbalance protection: Imbalance is determined by the absolute value of the difference between the main and auxiliary cells' SOH values, calculated as follows: SOH A Reduce SOH B The absolute value of the difference is used to trigger imbalance protection when the difference exceeds 20%.

[0089] Furthermore, power limiting is implemented in two steps: The first step is to limit the maximum discharge power of batteries with lower State of Harmony (SOH) to 70% of their rated power. The second step is to prioritize scheduling batteries with higher SOH to handle high power demands in each energy allocation decision, while batteries with lower SOH only handle the basic load.

[0090] Preferably, regarding the frequency of use adjustment, under short-distance operating conditions, if the SOH of the auxiliary battery B is significantly lower than that of the main battery A, and the difference is greater than a preset threshold, the controller further increases the range extension start threshold of the auxiliary battery B, that is, the auxiliary battery B intervenes later, reducing the actual number of times the auxiliary battery B is used.

[0091] The user alert mechanism is as follows: when the SOH is below 60% or the SOH difference exceeds 30%, the controller sends a battery health warning command to the instrument panel controller via the CAN bus. The instrument panel displays the corresponding battery health status icon, which can be either a yellow warning or a red alarm. After the trip is over, maintenance suggestions are pushed to the vehicle system.

[0092] Existing fixed SOC threshold strategies cannot detect battery aging, causing aged batteries to continue operating with new battery parameters, accelerating degradation. This embodiment achieves adaptive energy management throughout the entire battery lifecycle by dynamically linking real-time SOH assessment with the SOC threshold. It dynamically adjusts the charge and discharge boundaries based on the actual battery health condition, maximizing battery lifespan while ensuring system performance.

[0093] This embodiment employs a dual-core architecture with a main battery and a secondary battery, fully leveraging the high power and long lifespan of liquid lithium-ion batteries and the high energy density and high safety of semi-solid or solid-state batteries to achieve synergistic optimization of energy density and power performance. The main battery is located at the bottom of the vehicle, handling high-power output, while the secondary battery is placed in the trunk as a range-extending energy reserve. This differentiated spatial layout meets the functional positioning of the different batteries. A bidirectional DC / DC inverter enables voltage matching and energy transfer between the main and secondary batteries. The main and secondary batteries can be designed with independent voltage levels, and the DC / DC inverter flexibly matches different voltage platforms, solving the technical problem of single voltage platform limiting battery selection. The strategy of prioritizing the discharge of the main battery avoids the short cycle life of solid-state batteries. In short-distance driving scenarios, the secondary battery is almost never used, significantly extending its lifespan. The secondary battery and main battery work together to compensate for the low discharge rate of solid-state batteries, meeting high-power demands. The strategy of prioritizing charging the secondary battery to a second preset threshold during charging ensures sufficient range-extending energy reserves, preventing insufficient power in the secondary battery during long-distance driving and ensuring range extension.

[0094] Example 3 This embodiment provides a vehicle, including a main battery mounted on the vehicle; a secondary battery; a bidirectional high-power DC / DC inverter connecting the main battery and the secondary battery for charging and discharging voltage conversion of the secondary battery; a rear-drive MCU, with the main battery directly electrically connected to the rear-drive MCU and the secondary battery electrically connected to the rear-drive MCU through the bidirectional high-power DC / DC inverter; a fast and slow charging interface, with the main battery directly electrically connected to the fast and slow charging interface and the secondary battery electrically connected to the fast and slow charging interface through the bidirectional high-power DC / DC inverter; and a controller, including a memory and a processor, and computer instructions stored in the memory and running on the processor. When the computer instructions are executed by the processor, the steps of the above-described dual-core battery range extension method are completed.

[0095] Furthermore, the main battery is placed at the bottom of the electric vehicle, while the auxiliary battery is placed in the trunk. The main battery's placement at the bottom utilizes the space to house a large-capacity battery pack, providing the vehicle with primary electrical power. The auxiliary battery, located in the trunk, serves as a range-extending energy reserve. This differentiated spatial layout caters to the functional roles of the different batteries. Placing the main battery at the bottom helps lower the vehicle's center of gravity, improving handling stability; placing the auxiliary battery in the trunk facilitates maintenance and replacement, while also enhancing its safety.

[0096] Preferably, the bidirectional high-power DC / DC inverter performs voltage conversion on the auxiliary battery, matching its voltage with that of the main battery. The main battery and the auxiliary battery form a parallel power supply topology through the bidirectional high-power DC / DC inverter. The DC / DC inverter achieves voltage range matching between the auxiliary battery and the main battery, supporting bidirectional energy flow. The parallel power supply topology of the main battery and auxiliary battery allows them to jointly power the downstream MCU, or for the auxiliary battery to charge the main battery, enabling flexible energy management.

[0097] Specifically, the bidirectional high-power DC / DC inverter adopts either a bidirectional Buck-Boost topology or an LLC resonant topology. The bidirectional Buck-Boost topology is simple in structure and low in cost, making it suitable for economy vehicles; the LLC resonant topology is more efficient and suitable for long-term high-power charging and discharging scenarios and high-end vehicles. The bidirectional Buck-Boost topology includes components such as switching transistors, freewheeling diodes, inductors, and capacitors, and voltage rise and fall are achieved by adjusting the duty cycle of the switching transistors; the LLC resonant topology includes components such as resonant inductors, resonant capacitors, transformers, and full-bridge rectifier circuits, and voltage regulation is achieved by adjusting the switching frequency.

[0098] In some embodiments, the controller communicates with the main battery, the auxiliary battery, the bidirectional high-power DC / DC inverter, and the rear-drive MCU via a CAN bus. The CAN bus is a commonly used communication protocol in automotive electronic systems, offering high reliability, real-time performance, and interference resistance. The controller uses the CAN bus to collect real-time data on the state of charge, voltage, current, and temperature of the main and auxiliary batteries, sending charging and discharging power commands to the DC / DC inverter and torque commands to the rear-drive MCU, thereby achieving coordinated control of the vehicle's energy management.

[0099] As a preferred embodiment, the main battery and the auxiliary battery are respectively equipped with a voltage sensor, a current sensor, and a temperature sensor. The voltage sensor is used to monitor the battery terminal voltage, the current sensor is used to monitor the charging and discharging current, and the temperature sensor is used to monitor the battery temperature. The sensor sampling frequency is typically ≥10Hz to ensure that the controller can acquire battery status data in real time. The controller calculates the battery state of charge based on the sensor data, determines the battery health status, executes charging and discharging control strategies, and achieves precise energy management.

[0100] Furthermore, the bidirectional DC / DC inverter includes: an input terminal connected to a secondary battery; an output terminal connected to a main battery or a drive MCU; and a bidirectional power conversion circuit to realize voltage rise / fall and bidirectional energy flow between the input terminal and the output terminal.

[0101] In this embodiment, the following range extension method is executed according to the above-described dual-core battery range extender system: The main battery and the auxiliary battery are connected in parallel to the rear drive MCU of the electric vehicle through a bidirectional DC / DC inverter. The main battery is directly electrically connected to the rear drive MCU, and the auxiliary battery is electrically connected to the rear drive MCU through the bidirectional DC / DC inverter. The bidirectional DC / DC inverter performs charging and discharging voltage conversion on the auxiliary battery so that the voltage of the auxiliary battery matches the voltage of the main battery. During the discharge process, the controller prioritizes the discharge of the main battery; when the state of charge of the main battery drops to a first preset threshold, the controller controls the bidirectional DC / DC inverter to start, and the auxiliary battery begins to discharge. The bidirectional DC / DC inverter dynamically adjusts the charging power according to the state of charge of the main battery, so that the auxiliary battery charges the main battery or supplies power to the rear drive MCU together with the main battery. During the charging process, the controller prioritizes charging the auxiliary battery to a second preset threshold before charging the main battery.

[0102] This embodiment employs a dual-core architecture with a main battery and a secondary battery, achieving complementary advantages of different battery types. The main battery is directly connected to the drive MCU, undertaking high-power output tasks; the secondary battery is connected via a DC / DC inverter, serving as a range-extending energy reserve. During discharge, the main battery is prioritized to fully utilize its high power and long lifespan characteristics. When the main battery's state of charge drops to a first preset threshold, the secondary battery initiates range extension. At this time, the DC / DC inverter dynamically adjusts the charging power according to the main battery's state of charge: the lower the main battery's state of charge, the higher the charging power, quickly replenishing the main battery's charge; when the main battery's state of charge approaches the upper limit of the first preset threshold, the charging power gradually decreases to avoid overcharging. During charging, the secondary battery is prioritized for charging to a second preset threshold to ensure sufficient range-extending energy reserve before charging the main battery, until both batteries are fully charged.

[0103] Furthermore, the main battery is a liquid lithium-ion battery, and the auxiliary battery is a semi-solid-state battery or a solid-state battery. Liquid lithium-ion batteries have good power characteristics and long lifespan, making them suitable for high-power output tasks; semi-solid-state or solid-state batteries have high energy density and high safety characteristics, making them suitable as range-extending energy storage sources.

[0104] Preferably, the main battery has an energy density of 160-300 Wh / kg, a cycle life of ≥2000 cycles, and a discharge rate of ≥3C; the auxiliary battery has an energy density of 300-600 Wh / kg, a cycle life of 1000-1500 cycles, and a discharge rate of ≤1C. This parameter configuration ensures that the main battery can provide high power output and long cycle life, while the auxiliary battery provides high energy density range extension reserves. Although the energy density of the main battery is lower than that of the auxiliary battery, its high discharge rate capability and long cycle life make it the main power supply unit; the high energy density of the auxiliary battery compensates for the insufficient power of the main battery.

[0105] Preferably, the first preset threshold is typically set to 20%-30%, and the second preset threshold is typically set to 80%-90%. The first preset threshold is set to ensure the main battery maintains high power output when its state of charge (SOC) is above 20%, while power degradation is significant when the SOC is below 20%. Therefore, setting it to 20%-30% ensures the main battery's power output while providing a reasonable start-up opportunity for the auxiliary battery's range extension. The second preset threshold is set to ensure that semi-solid-state or solid-state batteries have high charging efficiency when the SOC is below 90%, while charging speed decreases significantly and the risk of overcharging increases when the SOC is above 90%. Therefore, setting it to 80%-90% ensures sufficient range extension reserve energy for the auxiliary battery while avoiding battery performance degradation caused by overcharging.

[0106] Furthermore, when the secondary battery charges the main battery, the bidirectional DC / DC inverter uses a proportional control algorithm to dynamically adjust the power. Specifically, the charging power command is calculated based on the deviation between the state of charge of the main battery and the first preset threshold. The larger the deviation, the greater the charging power. When the deviation approaches zero, the charging power gradually decreases to zero.

[0107] Specifically, the charging power command is as follows:

[0108] Wherein, K is a proportionality coefficient, which is taken as 1000W / % in this embodiment. The upper limit of the first preset threshold. The real-time state of charge of the main battery.

[0109] For example, when the main battery's state of charge (SOC) is 20%, the charging power command is 1000 × (25% - 20%) = 5 kW; when the main battery's SOC is 23%, the charging power command is 1000 × (25% - 23%) = 2 kW. The upper limit of the charging power is limited by the rated power of the DC / DC inverter, typically 30 kW.

[0110] In some embodiments, the system further includes adjusting the energy distribution strategy based on driving conditions: When the single driving mileage is less than a preset mileage threshold, the main battery is primarily used for discharge; when the single driving mileage is greater than or equal to the preset mileage threshold, the main battery is first used to discharge to the first preset threshold before the auxiliary battery is activated for range extension. The preset mileage threshold is typically set to 50km. For short-distance driving, in this embodiment, when the single driving mileage is <50km, the main battery is primarily used to reduce the frequency of auxiliary battery use and extend the cycle life of the auxiliary battery.

[0111] As a preferred embodiment, the energy distribution strategy is adjusted according to the ambient temperature. When the ambient temperature is below a preset temperature threshold, the main battery is used to discharge first, and the auxiliary battery reduces its output power or is shut down. The preset temperature threshold is usually set to 0°C. Under low-temperature conditions, the performance degradation of liquid lithium-ion batteries is less than that of semi-solid or solid batteries, so the main battery is used first.

[0112] Specifically, when the ambient temperature is below 0°C, the output power of the auxiliary battery is limited to 50%-70% of its rated power; when the ambient temperature is below -20°C, the auxiliary battery is deactivated, and the vehicle relies solely on the main battery for power. This strategy avoids the drawbacks of solid-state batteries, such as reduced ion mobility and limited discharge rate at low temperatures, ensuring the vehicle's power performance in low-temperature environments.

[0113] Furthermore, the main battery is directly connected to the fast and slow charging interfaces, and the fast and slow charging currents for the auxiliary battery are connected to the auxiliary battery through the bidirectional DC / DC inverter. The main battery can be charged independently via fast charging, while the auxiliary battery is charged through the DC / DC inverter, enabling flexible charging management of the dual-battery system. After the external fast and slow charging interfaces are connected, the controller prioritizes charging the auxiliary battery. When the auxiliary battery's state of charge reaches a second preset threshold, the controller switches the charging path and begins charging the main battery until both the main and auxiliary batteries are fully charged.

[0114] Preferably, the system further includes: a controller that determines battery faults by monitoring the voltage, current, and temperature anomalies of the main battery or the auxiliary battery. A battery fault is determined when a voltage deviation greater than 10%, a temperature higher than 60°C, or an internal resistance increase exceeding 50% is detected. When a battery fault is detected, the controller disconnects the faulty battery from the bidirectional DC / DC inverter, allowing the other battery to supply power independently. This redundant power supply design improves system reliability and safety. When either battery fails, the other battery can provide independent power, preventing the entire vehicle from breaking down. The controller monitors the voltage, current, and temperature data of the main and auxiliary batteries in real time, and collects sensor signals via the CAN bus. When a voltage deviation greater than 10% relative to the normal voltage range, a temperature higher than 60°C, or an internal resistance increase exceeding 50% relative to the initial internal resistance is detected, a battery fault is determined, and the electrical connection between the faulty battery and the DC / DC inverter is immediately disconnected, switching to an independent power supply mode for the other battery.

[0115] As one implementation method, a dynamic linkage mechanism between SOH assessment and SOC threshold is adopted for the first preset threshold and the second preset threshold of SOC.

[0116] SOH evaluation method: The controller collects three signals—terminal voltage, charging and discharging current, and battery temperature—from the main and auxiliary batteries via the CAN bus at a sampling frequency of 10Hz.

[0117] The internal resistance is calculated using the current pulse method. At each charge / discharge switching moment (current sudden change), the voltage sudden change ΔU and the current sudden change ΔI are recorded, and the DC internal resistance is calculated as follows: , The DC internal resistance is compared with the initial internal resistance R0 to calculate the internal resistance growth rate. for:

[0118] The capacity calculation uses the ampere-hour integration method, which integrates the current over time during each complete charge-discharge cycle to obtain the actual discharge capacity Q. actual Compared with the initial capacity Q0, the capacity retention rate wei is calculated.

[0119] The comprehensive calculation formula for SOH is:

[0120] The more severe of the two factors, internal resistance decay and capacity decay, is taken as the criterion for determining SOH.

[0121] The evaluation is triggered every 100 charge-discharge cycles or when the cumulative mileage reaches 5000 kilometers, triggering a SOH evaluation and updating the stored data. The SOH evaluation results are stored in the controller's non-volatile EEPROM, which is not lost after power failure, and the historical SOH value is directly read as the initial reference upon the next power-on.

[0122] Treatment when the SOH of secondary battery B is below 80%: A tiered adjustment strategy is adopted: when SOH is between 70% and 80%, the second preset threshold is lowered by 5%; when SOH is between 60% and 70%, the second preset threshold is lowered by 10%; when SOH is below 60%, the second preset threshold is lowered by 15%, and at the same time, a prompt is issued to the user to replace the auxiliary battery B.

[0123] The physical basis for the adjustment is that after solid-state or semi-solid-state batteries age, their charging acceptance in the high SOC range decreases significantly. Preferably, the high SOC range is defined as an SOC greater than 80%. Continuous high SOC charging accelerates lattice distortion of the cathode material. By lowering the charging cutoff SOC, the charging range is limited to the low SOC region with higher electrochemical activity, which can effectively slow down the capacity decay rate. Taking a 50kWh secondary battery B as an example, when the second preset threshold is reduced from 85% to 78%, the available range extension capacity decreases from 42.5kWh to 39kWh, reducing the driving range by approximately 20 kilometers. The controller simultaneously updates the estimated driving range and notifies the instrument panel display.

[0124] Handling when the SOH of main cell A is below 80%: A tiered adjustment strategy is adopted: when the SOH is between 70% and 80%, the first preset threshold is increased by 5%; when the SOH is between 60% and 70%, the first preset threshold is increased by 10%; when the SOH is below 60%, the first preset threshold is increased by 15%, and a prompt to replace the main battery A is issued to the user.

[0125] The physical basis for the adjustment is that after the liquid lithium-ion battery ages, the internal resistance in the low SOC range increases significantly. Preferably, the low SOC range is less than 20%. Deep discharge leads to accelerated loss of active lithium on the negative electrode. By increasing the discharge cutoff SOC, the main battery A is prevented from entering the high internal resistance deep discharge range, which can effectively delay capacity decay. After the first preset threshold is increased, the range extension start-up timing of the auxiliary battery B is advanced accordingly. While updating the first preset threshold, the controller simultaneously updates the range extension trigger judgment logic of the auxiliary battery B to ensure the overall consistency of the energy management strategy.

[0126] Dual-cell SOH imbalance protection: Imbalance is determined by the absolute value of the difference between the main and auxiliary cells' SOH values, calculated as follows: SOH A Reduce SOH B The absolute value of the difference is used to trigger imbalance protection when the difference exceeds 20%.

[0127] Furthermore, power limiting is implemented in two steps: The first step is to limit the maximum discharge power of batteries with lower State of Harmony (SOH) to 70% of their rated power. The second step is to prioritize scheduling batteries with higher SOH to handle high power demands in each energy allocation decision, while batteries with lower SOH only handle the basic load.

[0128] Preferably, regarding the frequency of use adjustment, under short-distance operating conditions, if the SOH of the auxiliary battery B is significantly lower than that of the main battery A, and the difference is greater than a preset threshold, the controller further increases the range extension start threshold of the auxiliary battery B, that is, the auxiliary battery B intervenes later, reducing the actual number of times the auxiliary battery B is used.

[0129] The user alert mechanism is as follows: when the SOH is below 60% or the SOH difference exceeds 30%, the controller sends a battery health warning command to the instrument panel controller via the CAN bus. The instrument panel displays the corresponding battery health status icon, which can be either a yellow warning or a red alarm. After the trip is over, maintenance suggestions are pushed to the vehicle system.

[0130] Existing fixed SOC threshold strategies cannot detect battery aging, causing aged batteries to continue operating with new battery parameters, accelerating degradation. This embodiment achieves adaptive energy management throughout the entire battery lifecycle by dynamically linking real-time SOH assessment with the SOC threshold. It dynamically adjusts the charge and discharge boundaries based on the actual battery health condition, maximizing battery lifespan while ensuring system performance.

[0131] This embodiment employs a dual-core architecture with a main battery and a secondary battery, fully leveraging the high power and long lifespan of liquid lithium-ion batteries and the high energy density and high safety of semi-solid or solid-state batteries to achieve synergistic optimization of energy density and power performance. The main battery is located at the bottom of the vehicle, handling high-power output, while the secondary battery is placed in the trunk as a range-extending energy reserve. This differentiated spatial layout meets the functional positioning of the different batteries. A bidirectional DC / DC inverter enables voltage matching and energy transfer between the main and secondary batteries. The main and secondary batteries can be designed with independent voltage levels, and the DC / DC inverter flexibly matches different voltage platforms, solving the technical problem of single voltage platform limiting battery selection. The strategy of prioritizing the discharge of the main battery avoids the short cycle life of solid-state batteries. In short-distance driving scenarios, the secondary battery is almost never used, significantly extending its lifespan. The secondary battery and main battery work together to compensate for the low discharge rate of solid-state batteries, meeting high-power demands. The strategy of prioritizing charging the secondary battery to a second preset threshold during charging ensures sufficient range-extending energy reserves, preventing insufficient power in the secondary battery during long-distance driving and ensuring range extension.

[0132] Example 4 This embodiment provides a computer-readable storage medium for storing computer instructions, which, when executed by a processor, complete the steps of the above-described dual-core battery range extension method.

[0133] Example 5 This embodiment provides a computer program product including executable instructions, which are computer instructions; the executable instructions are stored in a computer-readable storage medium. When the vehicle's processor reads the executable instructions from the computer-readable storage medium and executes the executable instructions, the steps of the aforementioned dual-core battery range extender method are completed.

[0134] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0135] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0136] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment, whereby a series of operational steps are performed to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0137] The steps and methods involved in Embodiments 2 to 5 above correspond to those in Embodiment 1. For detailed implementation methods, please refer to the relevant description section of Embodiment 1. The descriptions of each embodiment in the above embodiments have different emphases. Parts not described in detail in a certain embodiment can be referred to the relevant descriptions of other embodiments.

[0138] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0139] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for extending the range of a dual-core battery, characterized in that, include: The main battery and the auxiliary battery are connected in parallel to the rear drive MCU of the electric vehicle through a bidirectional DC / DC inverter. The bidirectional DC / DC inverter performs charge and discharge voltage conversion on the auxiliary battery so that the voltage of the auxiliary battery matches the voltage of the main battery. During the discharge process, the main battery is used to discharge first; when the state of charge of the main battery drops to a first preset threshold, the bidirectional DC / DC inverter is started, the auxiliary battery begins to discharge, and the bidirectional DC / DC inverter dynamically adjusts the charging power according to the state of charge of the main battery, so that the auxiliary battery charges the main battery or supplies power to the rear drive MCU together with the main battery. During the charging process, the auxiliary battery is charged to a second preset threshold first, and then the main battery is charged.

2. The dual-core battery range extender method as described in claim 1, characterized in that, The main battery is directly electrically connected to the rear-drive MCU, and the auxiliary battery is electrically connected to the rear-drive MCU through the bidirectional DC / DC inverter.

3. The dual-core battery range extender method as described in claim 1, characterized in that, The main battery is a liquid lithium-ion battery, and the auxiliary battery is a semi-solid battery or a solid battery.

4. The dual-core battery range extender method as described in claim 1, characterized in that, When the secondary battery charges the main battery, the bidirectional DC / DC inverter uses a proportional control algorithm for dynamic power adjustment. Specifically, it calculates the charging power command based on the deviation between the main battery's state of charge and the first preset threshold. Where K is the proportionality coefficient. The upper limit of the first preset threshold. The real-time state of charge of the main battery.

5. The dual-core battery range extender method as described in claim 1, characterized in that, This also includes adjusting the energy distribution strategy based on driving conditions: The energy distribution strategy is adjusted according to the driving mileage. When the single driving mileage is less than the preset mileage threshold, the main battery is used to discharge; when the single driving mileage is greater than or equal to the preset mileage threshold, the main battery is first used to discharge to the first preset threshold, and then the auxiliary battery is activated to extend the range.

6. The dual-core battery range extender method as described in claim 1, characterized in that, For the first preset threshold and the second preset threshold, a dynamic linkage mechanism between SOH assessment and SOC threshold is adopted, specifically: Every time a certain number of charge-discharge cycles are completed or the cumulative mileage reaches a threshold, a SOH assessment is triggered and the storage is updated. When the SOH of the auxiliary battery is below 80%, a tiered adjustment strategy is adopted. When the SOH of the auxiliary battery is between 70% and 80%, the second preset threshold is lowered by 5%; when the SOH of the auxiliary battery is between 60% and 70%, the second preset threshold is lowered by 10%; when the SOH of the auxiliary battery is below 60%, the second preset threshold is lowered by 15%, and a suggestion to replace the auxiliary battery is issued to the user. When the SOH of the main battery is below 80%, a tiered adjustment strategy is adopted. When the SOH of the main battery is between 70% and 80%, the first preset threshold is increased by 5%; when the SOH of the main battery is between 60% and 70%, the first preset threshold is increased by 10%; when the SOH of the main battery is below 60%, the first preset threshold is increased by 15%, and a suggestion to replace the main battery is issued to the user.

7. A dual-core battery range extender system, characterized in that, include: Main battery; secondary battery; bidirectional DC / DC inverter, connecting the main battery and the secondary battery, used for charging and discharging voltage conversion of the secondary battery; A rear-drive MCU, wherein the main battery is directly electrically connected to the rear-drive MCU, and the auxiliary battery is electrically connected to the rear-drive MCU through the bidirectional DC / DC inverter; a fast and slow charging interface, wherein the main battery is directly electrically connected to the fast and slow charging interface, and the auxiliary battery is electrically connected to the fast and slow charging interface through the bidirectional DC / DC inverter; and a controller configured to execute the dual-core battery range extension method according to any one of claims 1-6.

8. A vehicle, characterized in that, It includes a memory and a processor, as well as computer instructions stored in the memory and running on the processor, which, when executed by the processor, perform the dual-core battery range extension method according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, Used to store computer instructions, which, when executed by a processor, complete the dual-core battery range extension method according to any one of claims 1-6.

10. A computer program product comprising executable instructions stored in a computer-readable storage medium; wherein, When the vehicle's processor reads executable instructions from a computer-readable storage medium and executes the executable instructions, it completes the dual-core battery range extender method according to any one of claims 1-6.

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