A low-speed electric vehicle lead-acid lithium battery universal system

Abstract

This invention provides a universal lead-acid / lithium-ion battery system for low-speed electric vehicles, relating to the field of battery management system technology. The system includes a CAN bus, a main control unit, an integrated multimedia instrument panel, an inertial measurement unit, and an optional battery management system connected to the CAN bus. The main control unit, integrated multimedia instrument panel, and inertial measurement unit are permanent nodes on the CAN bus, while the battery management system is an optional node for lithium-ion battery configurations. The integrated multimedia instrument panel incorporates an automatic battery type identification module and a battery remaining capacity calculation module. It automatically determines the battery configuration type and switches the display mode by detecting the presence of battery management system messages on the CAN bus. The battery remaining capacity calculation module dynamically identifies driving conditions based on the current change rate and performs differentiated remaining capacity fusion calculations and display updates based on the driving condition classification results. This invention simplifies the vehicle's electrical architecture by adapting a single instrument system to both lead-acid and lithium-ion battery configurations, while improving the accuracy of the power display under lead-acid battery configurations.

Description

Technical Field

[0001] This invention relates to the field of battery management system technology, and in particular to a universal lead-acid lithium battery system for low-speed electric vehicles. Background Technology

[0002] Currently, low-speed electric vehicles are mainly equipped with two power storage solutions: lead-acid batteries and lithium batteries. Due to the differences in parameter acquisition principles and management methods between the two types of batteries, the existing vehicle electrical systems generally adopt separate instrument configurations: vehicles equipped with lead-acid batteries use dedicated lead-acid instruments to display voltage, current, and power, while vehicles equipped with lithium batteries use dedicated lithium battery instruments that connect to the battery management system to display battery parameters. At the same time, the in-vehicle multimedia entertainment functions are usually implemented by a separate multimedia terminal, which is separate from the instrument system.

[0003] The aforementioned separate architecture presents the following problems in actual production and use: On the one hand, the two battery configurations correspond to two independent instrument panels, resulting in a wide variety of production materials, increased material management and warehousing costs, and the need to differentiate between vehicle models during the production and assembly process, leading to low assembly efficiency and a high risk of errors. On the other hand, the separate setup of the instrument panel and multimedia terminal results in a dispersed vehicle electrical topology and complex wiring harness connections, which increases the overall vehicle wiring cost and reduces the reliability of the electrical system. In addition, existing lead-acid instrument panels mostly calculate the remaining power directly based on the real-time battery voltage. When the vehicle encounters continuous load fluctuations, the remaining power display value fluctuates frequently, resulting in an inflated and non-linear display of the remaining power, leading to poor accuracy of the power display perceived by the user and affecting the user experience.

[0004] Therefore, there is an urgent need for a universal instrument system that can be adapted to both lead-acid and lithium batteries and integrate multimedia functions, in order to simplify the vehicle's electrical architecture, reduce production and management costs, and improve the accuracy of power display under lead-acid battery configuration. Summary of the Invention

[0005] In view of this, the present invention proposes a universal lead-acid lithium battery system for low-speed electric vehicles. The system uses the CAN bus as the vehicle parameter transmission carrier and constructs a bus topology architecture that includes a main control unit, an integrated multimedia instrument, and an optional battery management system. Through the battery type automatic identification strategy and lead-acid battery remaining power anti-shake calculation algorithm built into the integrated multimedia instrument, universal adaptation between lithium battery and lead-acid battery configurations is achieved, while integrating in-vehicle multimedia functions.

[0006] The technical solution of this invention is implemented as follows:

[0007] A universal lead-acid lithium battery system for low-speed electric vehicles includes a CAN bus, a main control unit, an integrated multimedia instrument, an inertial measurement unit, and an optional battery management system that connects to the CAN bus.

[0008] The main control unit, integrated multimedia instrument, and inertial measurement unit are permanent nodes of the CAN bus, while the battery management system is an optional node under the lithium battery configuration.

[0009] The inertial measurement unit includes an accelerometer and a gyroscope, which are used to calculate the vehicle pitch angle and send the pitch angle status and uphill / downhill condition judgment results to the bus via the CAN bus.

[0010] The integrated multimedia instrument integrates a battery parameter display unit and an in-vehicle multimedia function unit, and has a built-in automatic battery type identification module and a battery remaining power calculation module.

[0011] The automatic battery type identification module is used to determine the vehicle battery configuration type and switch the corresponding display mode by detecting whether there are battery management system messages on the CAN bus.

[0012] When the configuration is determined to be a lithium battery, the integrated multimedia instrument receives and parses the battery parameter message sent by the battery management system, and displays the battery voltage, current, remaining power, temperature and fault information.

[0013] When the configuration is determined to be lead-acid battery, the integrated multimedia instrument receives and parses the battery voltage and current messages sent by the main control unit, and the battery remaining power calculation module performs differentiated remaining power fusion calculation and display update based on the working condition determination result.

[0014] Preferably, the addresses of each node on the CAN bus are defined as follows: the address of the battery management system is 0xF4, the address of the main control unit is 0xEF, the address of the integrated multimedia instrument is 0x28, and the address of the inertial measurement unit is 0x80; wherein the main control unit and the integrated multimedia instrument are both equipped with CAN bus terminating resistors.

[0015] Preferably, the CAN bus defines 6 frames of interactive messages, wherein:

[0016] The battery management system sends three frames of messages:

[0017] The first frame of the battery management system message includes the remaining battery power, total battery current, total battery voltage, battery fault level, and fault code information;

[0018] The second frame of the battery management system message contains information on the highest voltage, lowest voltage, and highest temperature of a single battery cell.

[0019] The third frame of the battery management system message contains voltage information for all individual battery cells;

[0020] The main control unit sends two frames of messages:

[0021] The first frame of the main control unit message includes gear information, main control unit operating status, accelerator pedal depth, motor speed, and main control unit fault code information;

[0022] The second frame of the main control unit message contains information on the total battery voltage, total battery current, drive motor temperature, and main control unit temperature.

[0023] The inertial measurement unit sends one message frame:

[0024] Includes the original value of the vehicle pitch angle, the slope condition indicator, and the continuous timer for the slope condition;

[0025] The integrated multimedia instrument is a pure receiver node on the CAN bus and does not send messages to the bus.

[0026] Preferably, the determination logic of the automatic battery type identification module is as follows: after the integrated multimedia instrument is powered on, it continuously listens to the CAN bus messages. If a valid battery management system message is detected within a preset period, it is determined that the vehicle is equipped with a lithium battery and enters the lithium battery display mode. If no battery management system message is detected, it is determined that the vehicle is equipped with a lead-acid battery and automatically switches to the lead-acid display mode.

[0027] Preferably, the battery remaining power calculation module has a built-in driving condition recognition unit, voltage anti-shake processing unit, ampere-hour integral correction unit, and slope condition compensation unit.

[0028] The driving condition identification unit is used to identify the current change rate reported by the main control unit. Classify and identify the current vehicle driving conditions: when When, it is determined to be a climbing or rapid acceleration condition; when At that time, it was determined to be a normal driving condition;

[0029] When the driving condition is determined to be normal, the voltage anti-shake processing unit continuously determines the stability of the battery voltage value reported by the main control unit. Only when the value in the same voltage range remains unchanged for a preset time without jumping across ranges, the voltage value is used as a valid sample value to query the pre-calibrated voltage-remaining power characteristic comparison table, obtain the corresponding remaining power value, and update the display.

[0030] The ramp condition compensation unit reads the vehicle pitch angle and ramp condition indicator output by the inertial measurement unit on the CAN bus:

[0031] When the pitch angle is greater than the uphill angle threshold, and the voltage anti-jitter processing unit confirms that the voltage remains stable for 60 seconds, it is determined to be a long uphill condition, and uphill compensation is performed on the original steady-state voltage:

[0032]

[0033] The main control unit reports the battery's steady-state initial voltage. Calculate the voltage after slope compensation; use the compensated voltage. Consult the pre-calibrated voltage-remaining power characteristic comparison table to obtain the remaining power value;

[0034] When the pitch angle is less than the downhill angle threshold, and the voltage anti-jitter processing unit confirms that the voltage remains stable for 60 seconds, it is determined to be a long downhill kinetic energy recovery condition, and downhill compensation is performed on the original steady-state voltage:

[0035]

[0036] Use the compensated voltage Consult the pre-calibrated voltage-remaining power characteristic comparison table to obtain the remaining power value.

[0037] Preferably, when the driving condition recognition unit determines that the vehicle is climbing a hill or accelerating rapidly, the voltage anti-shake processing unit locks the current remaining battery level display value unchanged, and the ampere-hour integral correction unit adjusts the current I... Perform time integration to calculate the actual power consumption during the specified operating period. And calculate the remaining power correction amount based on the battery's rated capacity C. After the uphill or rapid acceleration conditions are completed, the remaining battery level is adjusted by adding the remaining battery level correction amount to the locked remaining battery level. Generate the corrected remaining battery value and update the display.

[0038] Preferably, the preset rate of change threshold is 20 A / s; the starting point for the continuous timing of the driving condition recognition unit in determining the uphill rapid acceleration condition is... The endpoint is reached at the moment when the threshold is first exceeded. The voltage returns to below the threshold and the voltage fluctuation amplitude does not exceed ±0.5V for 5 consecutive seconds.

[0039] Preferably, the battery remaining power calculation module has a pre-calibrated lead-acid battery voltage-remaining power characteristic comparison table, which is calibrated through actual vehicle testing based on the correspondence between the discharge voltage and remaining power of a 72V lead-acid battery.

[0040] Preferably, the specific logic for the voltage anti-jitter processing unit to determine the continuous stability of the voltage value is as follows: record the timestamp of the voltage value entering the current voltage range, and continuously monitor whether the voltage value undergoes a cross-range jump; if the value in the same voltage range remains unchanged for 60 seconds without a cross-range jump, then use the voltage value as a valid sample value to query the voltage-remaining power characteristic lookup table, obtain the corresponding remaining power value, and update the display; if a cross-range jump occurs within 60 seconds, then the timer is reset to zero and the remaining power display value remains unchanged.

[0041] Preferably, after the rapid acceleration during the uphill climb ends, the ampere-hour integral correction unit adds the remaining power correction amount to the locked remaining power value. The corrected remaining battery power value is generated and fixed as the final display value, which is then output to the display interface of the integrated multimedia instrument. Under subsequent normal driving conditions, the voltage anti-shake processing unit continues to perform voltage lookup table updates based on the corrected remaining battery power value, without retrospectively correcting the display value at the end of the driving condition.

[0042] Compared with the prior art, the beneficial effects of the present invention are:

[0043] 1. This invention uses the CAN bus as the transmission carrier, sets the main control unit, integrated multimedia instrument, and inertial measurement unit as permanent nodes, and the battery management system as a lithium battery optional node. The automatic battery type identification module built into the instrument realizes automatic determination of battery configuration and switching of display mode based on the existence of battery management system messages. The unified node address definition, terminal resistor configuration and 6-frame interactive message protocol ensure communication reliability. At the same time, the instrument is set as a pure receiving node to reduce bus load and avoid communication conflicts. Thus, a single instrument system can adapt to both lead-acid and lithium battery configurations. This changes the traditional architecture of two separate instrument systems and separate instrument and multimedia terminal. It effectively reduces the types of production materials, reduces material management and storage costs, simplifies the vehicle electrical topology and wiring harness connection, improves assembly efficiency and system reliability, and eliminates the safety hazards of mismatch between instrument and battery type in manual configuration mode.

[0044] 2. This invention achieves a differentiated fusion calculation strategy of "normal operating condition voltage anti-shake lookup and high current operating condition ampere-hour integral correction" through the coordinated operation of the driving condition identification unit, voltage anti-shake processing unit, ampere-hour integral correction unit, and slope condition compensation unit. During normal driving, the invention filters out occasional voltage jumps by judging the continuous stability for 60 seconds. During rapid acceleration while climbing a slope, the invention locks the remaining power and performs background correction by calculating the actual power consumption based on the current integral. After the operating condition ends, the correction value is output. The start and end times of the operating condition are accurately defined by the 20A / s change rate threshold and the voltage stability condition for 5 consecutive seconds. This fundamentally distinguishes between the polarization transient state and the true charge steady state of lead-acid batteries. It completely solves the problem of frequent jumps and falsely high remaining power caused by the traditional lead-acid instrument relying solely on real-time voltage lookup. At the same time, it avoids the phenomenon of "false recovery" of remaining power after the operating condition ends, and significantly improves the power display accuracy and the accuracy of the user's judgment of the driving range across the entire operating condition range.

[0045] 3. This invention incorporates a voltage-remaining power characteristic comparison table calibrated under actual vehicle load conditions using a 72V lead-acid battery. The recorded value is the terminal voltage under driving load conditions, rather than the static open-circuit voltage, eliminating the system deviation when the open-circuit voltage calibration method is applied to dynamic scenarios. At the same time, the voltage anti-shake preset duration is set to 60 seconds, taking into account both the time required for the voltage to recover from polarization to a steady state and the user's need for the response speed of the remaining power. It achieves the best balance between "anti-shake" and "response", ensuring the accuracy of the remaining power query and the smoothness of the output from two dimensions: data source and time determination, effectively improving the user's driving experience and the trust in the power display. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 This is a diagram of a universal lead-acid lithium battery system architecture for low-speed electric vehicles according to the present invention.

[0048] Figure 2 This is a structural diagram of the integrated multimedia instrument of the present invention;

[0049] Figure 3 This is a flowchart illustrating the workflow of the integrated multimedia instrument of the present invention.

[0050] Figure 4 This is a voltage-remaining charge characteristic comparison table for the present invention; Detailed Implementation

[0051] To better understand the technical content of this invention, a specific embodiment is provided below, and the invention will be further described in conjunction with the accompanying drawings.

[0052] See Figures 1 to 4 The present invention provides a universal lead-acid lithium battery system for low-speed electric vehicles. The universal lead-acid lithium battery system for low-speed electric vehicles includes a CAN (Controller Area Network) bus, a main control unit, an integrated multimedia instrument, an inertial measurement unit, and a battery management system that can be optionally connected to the CAN bus.

[0053] The main control unit, integrated multimedia instrument, and inertial measurement unit are permanent nodes of the CAN bus, while the battery management system is an optional node in the lithium battery configuration.

[0054] The inertial measurement unit includes an accelerometer and a gyroscope, which are used to calculate the vehicle pitch angle and send the pitch angle status and uphill / downhill condition judgment results to the bus via the CAN bus;

[0055] The integrated multimedia instrument panel integrates a battery parameter display unit and an in-vehicle multimedia function unit, and also has a built-in automatic battery type identification module and a battery remaining power calculation module.

[0056] The automatic battery type identification module is used to determine the vehicle battery configuration type and switch the corresponding display mode by detecting the presence of battery management system messages on the CAN bus.

[0057] When the battery configuration is determined to be lithium battery, the integrated multimedia instrument receives and parses the battery parameter messages sent by the battery management system, and displays the battery voltage, current, remaining capacity, temperature and fault information.

[0058] When the battery configuration is determined to be lead-acid, the integrated multimedia instrument receives and parses the battery voltage and current messages sent by the main control unit. The remaining battery power calculation module then performs differentiated remaining power calculation and display update based on the operating condition determination results.

[0059] like Figure 1 As shown, the present invention provides a universal lead-acid lithium battery system for low-speed electric vehicles, the core of which lies in constructing a vehicle electrical topology architecture with CAN bus as the transmission carrier. For example... Figure 3As shown, when this system is working, the battery type automatic identification module automatically determines the current vehicle's battery configuration type by detecting whether there are battery management system messages on the CAN bus: when a battery management system message is detected, it is determined to be a lithium battery configuration, and the instrument panel directly receives and parses the battery parameter message sent by the battery management system, which includes remaining power, voltage, current, temperature, and fault information, and displays it; when no battery management system message is detected, it is determined to be a lead-acid battery configuration, and the instrument panel instead receives and parses the battery voltage and current messages sent by the main control unit, and the battery remaining power calculation module performs differentiated remaining power fusion calculation and display update based on the real-time operating condition identification results. Through the above technical solution, this invention adapts to both lead-acid and lithium battery configurations with a single integrated multimedia instrument panel, changing the existing situation where two battery configurations correspond to two independent instruments and the instrument panel and multimedia terminal are set up separately. This effectively reduces the types of production materials, lowers material management and warehousing costs, simplifies the vehicle's electrical topology and wiring harness connections, and improves assembly efficiency and electrical system reliability. More importantly, addressing the technical shortcomings of lead-acid batteries, such as voltage drops during high-current discharge conditions like climbing hills and rapid acceleration, which cause frequent fluctuations and inaccurate readings of remaining battery power, this invention uses a built-in battery remaining battery power calculation module to perform differentiated remaining battery power fusion calculations based on operating conditions. This solves the problem of traditional lead-acid instrument panels having a single display logic and being unable to adapt to complex road conditions, significantly improving the accuracy of battery power display and the user experience under lead-acid battery configurations.

[0060] Preferably, the addresses of each node on the CAN bus are defined as follows: the address of the battery management system is 0xF4, the address of the main control unit is 0xEF, the address of the integrated multimedia instrument is 0x28, and the address of the inertial measurement unit is 0x80; wherein the main control unit and the integrated multimedia instrument are both equipped with CAN bus terminating resistors.

[0061] Through the unified definition of the above node addresses, the system establishes a clear node identification and arbitration mechanism at the CAN bus communication level. The battery management system sends three frames of messages containing information on remaining power, total battery voltage, total current, fault level, and individual cell voltage using address 0xF4. The main control unit sends two frames of messages containing information on gear position, accelerator pedal depth, motor speed, total battery voltage, and total current using address 0xEF. The integrated multimedia instrument uses address 0x28 as a pure receiving node to listen to and parse all messages on the bus. The inertial measurement unit is configured with address 0x80 and periodically outputs the original value of the vehicle pitch angle, the slope condition identifier, and the slope status continuous timing message, providing the slope attitude data source for the slope condition compensation unit inside the instrument. The differentiated allocation of each node address ensures the determinism of message priority during bus arbitration and avoids communication disorder caused by address conflicts. Meanwhile, CAN bus terminating resistors are configured at the two physical end nodes of the main control unit and the integrated multimedia instrument, which effectively eliminates the reflection phenomenon of bus signals at the end of the transmission cable, ensuring signal integrity under high-speed communication, and enabling the system to transmit battery parameters and control information stably and reliably under the complex electromagnetic environment of low-speed electric vehicles.

[0062] Preferably, the CAN bus defines 6 frames of interactive messages, in which:

[0063] The battery management system sends three frames of messages:

[0064] The first frame of the battery management system message includes the remaining battery power, total battery current, total battery voltage, battery fault level, and fault code information;

[0065] The second frame of the battery management system message contains information on the highest voltage, lowest voltage, and highest temperature of a single battery cell.

[0066] The third frame of the battery management system message contains voltage information for all individual battery cells;

[0067] The main control unit sends two frames of messages:

[0068] The first frame of the main control unit message includes gear information, main control unit operating status, accelerator pedal depth, motor speed, and main control unit fault code information;

[0069] The second frame of the main control unit message contains information on the total battery voltage, total battery current, drive motor temperature, and main control unit temperature.

[0070] The inertial measurement unit sends one message frame:

[0071] Includes the original value of the vehicle pitch angle, the slope condition indicator, and the continuous timer for the slope condition;

[0072] Integrated multimedia instruments are pure receiver nodes on the CAN bus and do not send messages to the bus.

[0073] Through the unified definition of the aforementioned six message frames, the system establishes a complete and reasonably redundant set of battery and control parameter information at the CAN bus communication level. When the system is configured with a lithium battery, the three message frames from the battery management system fully cover all key information required for lithium battery management, including remaining capacity, total voltage and current, individual cell voltage distribution, individual cell extreme values ​​and temperature, and fault level, providing a data source for the instrument's lithium battery display mode. When the system is configured with a lead-acid battery, the battery management system node does not exist on the bus. The battery total voltage and current information contained in the second message frame sent by the main control unit supports the operating condition identification and ampere-hour integral correction calculation of the remaining battery capacity calculation module, ensuring that the instrument can still obtain the complete raw data required for capacity calculation in lead-acid mode. The information such as accelerator pedal depth and motor speed provided by the first message frame from the main control unit further provides auxiliary judgment basis for the dynamic identification of driving conditions, improving the response accuracy of the remaining battery capacity calculation module under different driving conditions. The integrated multimedia instrument cluster is configured as a pure receiver node on the CAN bus, without sending any messages to the bus. This design fundamentally eliminates communication risks such as bus arbitration conflicts, packet loss, or erroneous frame injection that might occur if the instrument cluster were a transmitter node. It reduces the bus load rate, allowing the instrument cluster to complete all battery parameter display and multimedia interaction functions without occupying bus transmission resources. It also simplifies the development complexity of the instrument cluster's CAN communication protocol stack. The original vehicle pitch angle value is obtained from the vehicle attitude angle data calculated by the inertial measurement unit using accelerometers and gyroscopes. The slope condition flag is used to characterize the current road condition of the vehicle, defined using a state coding method: 0 represents flat road condition, 1 represents long uphill condition, and 2 represents long downhill kinetic energy recovery condition. The slope condition duration timer records the continuous duration of the current slope condition. This invention achieves centralized sharing of battery and control information on a single CAN bus at the vehicle level, avoiding signal duplication and wiring redundancy caused by incompatible communication protocols in existing discrete instrument cluster architectures.

[0074] Preferably, the determination logic of the automatic battery type identification module is as follows: after the integrated multimedia instrument is powered on, it continuously listens to the CAN bus messages. If a valid battery management system message is detected within a preset period, it is determined that the vehicle is equipped with a lithium battery and enters the lithium battery display mode. If no battery management system message is detected, it is determined that the vehicle is equipped with a lead-acid battery and automatically switches to the lead-acid display mode.

[0075] In a preferred embodiment of the present invention, the determination logic of the automatic battery type identification module is as follows: after the integrated multimedia instrument panel is powered on, it continuously listens to CAN bus messages. If a valid battery management system message is detected within a preset period, it is determined that the vehicle is equipped with a lithium battery and enters the lithium battery display mode. The preset period can be 60 seconds. If no battery management system message is detected for 60 seconds, it is determined that the vehicle is equipped with a lead-acid battery and automatically switches to the lead-acid display mode. This determination logic utilizes the differentiated characteristics of the aforementioned CAN bus message frame definition. Under the lithium battery configuration, the battery management system node periodically sends three frames of messages containing information such as remaining power, total battery voltage, total current, single cell voltage, and fault level to the bus at address 0xF4. Under the lead-acid configuration, there is no battery management system node or its messages on the bus. Therefore, the existence of the battery management system message itself constitutes a unique and sufficient identifier for the lithium battery configuration. This system is compatible with both battery configurations, eliminating the problems of complex production material management and easy errors in assembly processes caused by two independent instruments corresponding to two battery configurations in the prior art. On the other hand, it also avoids the safety hazard of the instrument display mode not matching the actual vehicle battery type due to operational errors in the manual configuration method.

[0076] Preferred, such as Figure 2 As shown, the battery remaining power calculation module has a built-in driving condition recognition unit, voltage anti-shake processing unit, ampere-hour integral correction unit and slope condition compensation unit.

[0077] The driving condition identification unit is used to identify the current change rate reported by the main control unit. Classify and identify the current vehicle driving conditions: when When, it is determined to be a climbing or rapid acceleration condition; when At that time, it was determined to be a normal driving condition;

[0078] When the driving condition is determined to be normal, the voltage anti-shake processing unit continuously determines the stability of the battery voltage value reported by the main control unit. Only when the value in the same voltage range remains unchanged for a preset time without jumping across ranges, the voltage value is used as a valid sample value to query the pre-calibrated voltage-remaining power characteristic comparison table, obtain the corresponding remaining power value, and update the display.

[0079] The ramp condition compensation unit reads the vehicle pitch angle and ramp condition indicator output by the inertial measurement unit on the CAN bus:

[0080] When the pitch angle is greater than the uphill angle threshold, and the voltage anti-jitter processing unit confirms that the voltage remains stable for 60 seconds, it is determined to be a long uphill condition, and uphill compensation is performed on the original steady-state voltage:

[0081]

[0082] The main control unit reports the battery's steady-state initial voltage. Calculate the voltage after slope compensation; use the compensated voltage. Consult the pre-calibrated voltage-remaining power characteristic comparison table to obtain the remaining power value;

[0083] When the pitch angle is less than the downhill angle threshold, and the voltage anti-jitter processing unit confirms that the voltage remains stable for 60 seconds, it is determined to be a long downhill kinetic energy recovery condition, and downhill compensation is performed on the original steady-state voltage:

[0084]

[0085] Use the compensated voltage Consult the pre-calibrated voltage-remaining power characteristic comparison table to obtain the remaining power value.

[0086] The uphill compensation coefficient of 1.2 and the downhill compensation coefficient of 0.9 were obtained based on the actual vehicle voltage drop characteristics calibration of a 72V lead-acid battery at an 8% slope.

[0087] In a preferred embodiment of the present invention, the driving condition identification unit is used to identify the current change rate reported by the main control unit. Classify and identify the current vehicle driving conditions. When When, it is determined to be a climbing or rapid acceleration condition; when When the condition is determined to be normal driving condition, the voltage anti-shake processing unit continuously determines the stability of the battery voltage value reported by the main control unit. Only when the value in the same voltage range remains unchanged for a preset time without jumping across ranges will the voltage value be used as a valid sample value to query the pre-calibrated voltage-remaining power characteristic comparison table, obtain the corresponding remaining power value, and update the display.

[0088] During high-current discharge conditions such as vehicle climbing and rapid acceleration, lead-acid batteries cannot respond instantaneously to sudden current changes in their internal electrochemical reaction rate. This leads to severe ohmic and concentration polarization on the electrode surfaces, causing the battery terminal voltage to drop sharply. This voltage drop primarily reflects the polarization transient rather than the battery's true state of charge. Furthermore, the terminal voltage fluctuates frequently with current fluctuations. If the voltage-remaining charge table is consulted directly based on the real-time voltage, the displayed remaining charge value will show significant abnormal fluctuations and falsely low values, severely interfering with the driver's judgment of remaining driving range. To address this technical deficiency, this invention uses a driving condition identification unit to monitor the current change rate reported by the main control unit in real time. When a sudden increase in the rate of change of current is detected, When the preset rate of change threshold is reached, it is determined that the vehicle has entered a rapid acceleration condition for climbing a hill. At this time, the voltage anti-shake processing unit actively locks the current remaining power display value to avoid the remaining power from jumping due to falsely low voltage.

[0089] Preferably, when the driving condition recognition unit determines that the vehicle is climbing a hill or accelerating rapidly, the voltage anti-shake processing unit locks the current remaining battery level display value unchanged, while the ampere-hour integral correction unit adjusts the current... Perform time integration to calculate the actual power consumption during the specified operating period. And calculate the remaining power correction amount based on the battery's rated capacity C. After the uphill or rapid acceleration conditions are completed, the locked remaining battery value will be added to the remaining battery correction amount. Generate the corrected remaining battery value and update the display.

[0090] The ampere-hour integral correction unit integrates the current over time to calculate the actual power consumption during the operating condition period. Once the current change rate falls below the threshold and voltage fluctuations stabilize, the locked remaining power value is superimposed with the correction amount obtained from the ampere-hour integral to generate the corrected remaining power value, which is then output. This accurately reflects the battery's true power consumption during the operating condition by correcting the "locked remaining power value before the operating condition" with the "actual power consumption during the operating condition period." The threshold parameters mentioned above are based on actual vehicle calibration. Using a 72V / 100Ah lead-acid battery as the calibration object, 0-50km / h rapid acceleration and hill-climbing full-throttle acceleration tests were conducted on a flat road and a standard slope with an 8% gradient. The battery's total current and total voltage data were continuously collected via the CAN bus at a sampling frequency of 10Hz. Statistical analysis of the collected current change rate data showed that the current change rate under normal driving conditions is mostly concentrated in the 5-15A / s range, while the peak current change rate under rapid acceleration and hill-climbing conditions generally exceeds 20A / s. Based on this, the preset... The rate of change threshold is calibrated to 20A / s to reliably distinguish between the two types of operating conditions. The condition of "voltage fluctuation amplitude not exceeding ±0.5V for 5 consecutive seconds" is introduced in the termination judgment of the ramp-up and rapid acceleration operating condition. The calibration basis is also derived from the above test data. Statistical results show that after the large current discharge ends, the battery terminal voltage recovers to a stable state with a fluctuation range within ±0.5V. The time required is usually 3-7 seconds. The middle value of 5 seconds is taken as the judgment condition. This avoids the inaccurate correction caused by premature exit from the operating condition before the voltage has stabilized, and also prevents the delay in updating the remaining power caused by excessively extended lock-in time. Through the above technical solution, this invention achieves a differentiated fusion calculation strategy of "normal operating condition voltage anti-shake lookup table and high current fluctuation operating condition ampere-hour integral correction" by the coordinated cooperation of four functional units. It distinguishes between the polarization transient state and the true charge steady state of lead-acid batteries. Without adding additional current sensor hardware, it solves the technical defects of traditional lead-acid instrument display logic being simple, and the frequent jumps and false low remaining power during rapid acceleration and hill climbing. As a result, the accuracy of remaining power display is significantly improved across the entire operating range under lead-acid battery configuration, effectively improving the user's driving experience.

[0091] Preferably, the preset change rate threshold is 20A / s; the starting point for the continuous timing of the uphill rapid acceleration condition determined by the driving condition identification unit is the moment when |dI / dt| first exceeds the threshold, and the ending point is when |dI / dt| returns to below the threshold and the voltage fluctuation amplitude does not exceed ±0.5V for 5 consecutive seconds.

[0092] Due to the characteristics of lead-acid batteries, when a vehicle climbs a hill or accelerates rapidly, the battery voltage drops sharply while outputting a large current. If the remaining charge is immediately displayed based on the voltage, the voltage will fluctuate frequently. The threshold and judgment conditions are based on in-depth research on the electrical characteristics of lead-acid batteries under dynamic operating conditions and the results of actual vehicle calibration tests: using a 72V / 100Ah lead-acid battery as the calibration object, 0-50km / h rapid acceleration and hill climbing full-throttle acceleration tests were conducted on flat roads and standard slope roads. The battery's total current and voltage data are continuously collected via the CAN bus at a sampling frequency of 10Hz. Statistical analysis of the collected current change rate data reveals that under normal driving conditions, the current change rate is mostly concentrated in the 5-15A / s range, while the peak current change rate under rapid acceleration and hill-climbing conditions generally exceeds 20A / s. Therefore, a preset change rate threshold of 20A / s is set. This ensures reliable differentiation between the two types of conditions, preventing small current fluctuations during normal driving from being misjudged as hill-climbing rapid acceleration, while also preventing the overly high threshold from missing genuine hill-climbing rapid acceleration processes. The starting point of the driving condition is... The moment the current discharge rate first exceeds 20A / s is used as the benchmark to ensure that the system can immediately trigger the remaining capacity lock and ampere-hour integral correction mechanism at the instant of high-current discharge, thus promptly preventing incorrect display of remaining capacity due to falsely low voltage. For determining the end point of the operating condition, statistical calibration test data shows that the time required for the battery terminal voltage to recover from the polarized state to a stable state (i.e., the voltage fluctuation amplitude returning to within ±0.5V) after the high-current discharge is typically 3 to 7 seconds. The midpoint of 5 seconds is taken as the criterion. The necessary conditions for ending the operating condition are that the voltage fluctuation amplitude does not exceed ±0.5V for 5 consecutive seconds and the current rate of change falls below the threshold. The technical consideration is that the current rate of change falling below the threshold only means that the driver has stopped the high-throttle operation. However, at this time, the concentration polarization and ohmic polarization inside the battery have not completely subsided, and the terminal voltage is still in the fluctuation recovery period. If only the current drop is used as the end of the operating condition, the voltage anti-shake processing unit will immediately resume sampling and monitoring the real-time voltage. At this time, the voltage-remaining capacity characteristic lookup table will still give a lower remaining capacity value. As a result, the actual power consumption correction calculated by the ampere-hour integral correction unit during the operating condition will be covered by the unstable voltage lookup table value. Therefore, it is necessary to simultaneously require the voltage fluctuation amplitude to be stable for more than 5 consecutive seconds to ensure that the battery terminal voltage has substantially returned to the steady-state level corresponding to the true remaining capacity before the hill-climbing rapid acceleration operating condition can be ended and the corrected remaining capacity value can be output.

[0093] Preferred, such as Figure 4 As shown, the battery remaining power calculation module has a pre-calibrated lead-acid battery voltage-remaining power characteristic comparison table. The characteristic comparison table is based on the correspondence between the discharge voltage and remaining power of a 72V lead-acid battery and is calibrated through actual vehicle testing.

[0094] Traditional battery voltage-remaining capacity characteristics are calibrated using the static open-circuit voltage method. However, since there is a significant difference between the open-circuit voltage measured in the static state and the terminal voltage under load discharge, directly applying the open-circuit voltage-remaining capacity correspondence to the real-time voltage lookup table during driving will result in a large error in the calculation of remaining capacity. Therefore, this invention designs the calibration process in a simulated actual driving condition under real vehicle conditions: the fully loaded vehicle is placed on the chassis dynamometer, and different remaining capacity nodes are simulated using constant current discharge, from 100% to 0%, with a step interval of 5%. Under load operation, after each remaining capacity node has been stably operated under load for a preset time, the total battery voltage value reported by the main control unit and the corresponding actual remaining capacity value are recorded, forming a load discharge voltage-remaining capacity comparison table covering the entire remaining capacity range and pre-stored in the instrument's non-volatile memory. Through the aforementioned vehicle-load calibration scheme, the voltage values ​​recorded in the voltage-remaining capacity characteristic comparison table are all the terminal voltages of the battery under actual driving load conditions, rather than the static open-circuit voltage. This ensures that the remaining capacity value obtained by the voltage anti-shake processing unit when querying the comparison table under normal driving conditions strictly corresponds to the actual remaining capacity of the battery under actual load conditions, eliminating the inherent system deviation when the open-circuit voltage calibration method is applied to dynamic driving scenarios. Simultaneously, using 72V, the most representative nominal voltage platform for lead-acid batteries in the low-speed electric vehicle field, as the calibration benchmark, this characteristic comparison table can cover the general adaptation requirements of most low-speed electric vehicle lead-acid battery configurations. This provides the battery remaining capacity calculation module with an accurate and reliable data query benchmark across all operating conditions, ensuring the final output accuracy of the differentiated fusion calculation strategy from the data source level.

[0095] Preferably, the specific logic for the voltage anti-jitter processing unit to determine the continuous stability of the voltage value is as follows: Record the timestamp of the voltage value entering the current voltage range, and continuously monitor whether the voltage value undergoes a cross-range jump; if the value in the same voltage range remains unchanged for 60 seconds without a cross-range jump, then use this voltage value as a valid sample value to query the voltage-remaining power characteristic lookup table, obtain the corresponding remaining power value, and update the display. If a cross-range jump occurs within 60 seconds, the timer is reset to zero and restarted, while the remaining power display value remains unchanged.

[0096] Based on real-vehicle testing, using the voltage recovery characteristics of a 72V / 100Ah lead-acid battery under different driving conditions as a benchmark, the preset duration of 60 seconds can cover the time required for the voltage to transition from transient fluctuations to a long-term steady state under most normal driving conditions, while also ensuring timely updates of the remaining battery level display on the instrument panel when the vehicle is continuously and stably driving.

[0097] Preferably, after the rapid acceleration during hill climbing ends, the ampere-hour integral correction unit adds the remaining battery power correction amount to the locked remaining battery power value. The corrected remaining battery value is generated and fixed as the final display value, which is then output to the display interface of the integrated multimedia instrument. Under subsequent normal driving conditions, the voltage anti-shake processing unit continues to perform voltage lookup and update based on the corrected remaining battery value, without retrospectively correcting the display value at the end of the driving condition.

[0098] Under subsequent normal driving conditions, the voltage anti-shake processing unit uses the fixed corrected remaining battery value as the display reference. Based on this, it performs subsequent battery updates through voltage anti-shake judgment and table lookup operations, without retrospectively correcting the displayed value already output at the end of the driving condition. Through the above processing, this invention can output an accurate corrected remaining battery value in one go after the high-current discharge condition ends without waiting for the voltage to recover to a steady state. This fundamentally avoids the false rebound phenomenon caused by the initially low and then gradually rebounding remaining battery value during the voltage recovery process in traditional solutions. It ensures that the remaining battery display curve remains monotonically decreasing and close to the true discharge curve throughout the entire uphill rapid acceleration process, significantly improving the driver's confidence in the battery display and the accuracy of the remaining driving range judgment.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A universal lead-acid lithium battery system for low-speed electric vehicles, characterized in that, It includes a CAN bus, a main control unit, an integrated multimedia instrument, an inertial measurement unit, and an optional battery management system that connects to the CAN bus; The main control unit, integrated multimedia instrument, and inertial measurement unit are permanent nodes of the CAN bus, while the battery management system is an optional node under the lithium battery configuration. The inertial measurement unit includes an accelerometer and a gyroscope, which are used to calculate the vehicle pitch angle and send the pitch angle status and uphill / downhill condition judgment results to the bus via the CAN bus. The integrated multimedia instrument integrates a battery parameter display unit and an in-vehicle multimedia function unit, and has a built-in automatic battery type identification module and a battery remaining power calculation module. The automatic battery type identification module is used to determine the vehicle battery configuration type and switch the corresponding display mode by detecting whether there are battery management system messages on the CAN bus. When the configuration is determined to be a lithium battery, the integrated multimedia instrument receives and parses the battery parameter message sent by the battery management system, and displays the battery voltage, current, remaining power, temperature and fault information. When the configuration is determined to be lead-acid battery, the integrated multimedia instrument receives and parses the battery voltage and current messages sent by the main control unit, and the battery remaining power calculation module performs differentiated remaining power fusion calculation and display update based on the working condition determination result.

2. The universal lead-acid lithium battery system for low-speed electric vehicles according to claim 1, characterized in that, The addresses of each node on the CAN bus are defined as follows: the address of the battery management system is 0xF4, the address of the main control unit is 0xEF, the address of the integrated multimedia instrument is 0x28, and the address of the inertial measurement unit is 0x80; among them, the main control unit and the integrated multimedia instrument are both equipped with CAN bus terminating resistors.

3. The universal lead-acid lithium battery system for low-speed electric vehicles according to claim 1, characterized in that, The CAN bus defines 6 frames of interactive messages, among which: The battery management system sends three frames of messages: The first frame of the battery management system message includes the remaining battery power, total battery current, total battery voltage, battery fault level, and fault code information; The second frame of the battery management system message contains information on the highest voltage, lowest voltage, and highest temperature of a single battery cell. The third frame of the battery management system message contains voltage information for all individual battery cells; The main control unit sends two frames of messages: The first frame of the main control unit message includes gear information, main control unit operating status, accelerator pedal depth, motor speed, and main control unit fault code information; The second frame of the main control unit message contains information on the total battery voltage, total battery current, drive motor temperature, and main control unit temperature. The inertial measurement unit sends one message frame: Includes the original value of the vehicle pitch angle, the slope condition indicator, and the continuous timer for the slope condition; The integrated multimedia instrument is a pure receiver node on the CAN bus and does not send messages to the bus.

4. The universal lead-acid lithium battery system for low-speed electric vehicles according to claim 1, characterized in that, The determination logic of the automatic battery type identification module is as follows: after the integrated multimedia instrument is powered on, it continuously listens to the CAN bus messages. If a valid battery management system message is detected within a preset period, it is determined that the vehicle is equipped with a lithium battery and enters the lithium battery display mode. If no battery management system message is detected, it is determined that the vehicle is equipped with a lead-acid battery and automatically switches to the lead-acid display mode.

5. A universal lead-acid lithium battery system for low-speed electric vehicles according to claim 1, characterized in that, The battery remaining power calculation module has a built-in driving condition identification unit, voltage anti-shake processing unit, ampere-hour integral correction unit and slope condition compensation unit. The driving condition identification unit is used to identify the current change rate reported by the main control unit. Classify and identify the current vehicle driving conditions: when When, it is determined to be a climbing or rapid acceleration condition; when At that time, it was determined to be a normal driving condition; When the driving condition is determined to be normal, the voltage anti-shake processing unit continuously determines the stability of the battery voltage value reported by the main control unit. Only when the value in the same voltage range remains unchanged for a preset time without jumping across ranges, the voltage value is used as a valid sample value to query the pre-calibrated voltage-remaining power characteristic comparison table, obtain the corresponding remaining power value, and update the display. The ramp condition compensation unit reads the vehicle pitch angle and ramp condition indicator output by the inertial measurement unit on the CAN bus: When the pitch angle is greater than the uphill angle threshold, and the voltage anti-jitter processing unit confirms that the voltage remains stable for 60 seconds, it is determined to be a long uphill condition, and uphill compensation is performed on the original steady-state voltage: The main control unit reports the battery's steady-state initial voltage. Calculate the voltage after slope compensation; use the compensated voltage. Consult the pre-calibrated voltage-remaining power characteristic comparison table to obtain the remaining power value; When the pitch angle is less than the downhill angle threshold, and the voltage anti-jitter processing unit confirms that the voltage remains stable for 60 seconds, it is determined to be a long downhill kinetic energy recovery condition, and downhill compensation is performed on the original steady-state voltage: Use the compensated voltage Consult the pre-calibrated voltage-remaining power characteristic comparison table to obtain the remaining power value.

6. A universal lead-acid lithium battery system for low-speed electric vehicles according to claim 5, characterized in that, When the driving condition recognition unit determines that the vehicle is climbing a hill or accelerating rapidly, the voltage anti-shake processing unit locks the current remaining battery level display value unchanged, while the ampere-hour integral correction unit adjusts the current... Perform time integration to calculate the actual power consumption during the specified operating period. And calculate the remaining power correction amount based on the battery's rated capacity C. After the uphill or rapid acceleration conditions are completed, the remaining battery level is adjusted by adding the remaining battery level correction amount to the locked remaining battery level. Generate the corrected remaining battery value and update the display.

7. A universal lead-acid lithium battery system for low-speed electric vehicles according to claim 5, characterized in that, The preset rate of change threshold is 20A / s; the driving condition identification unit determines the starting point for the continuous timing of the uphill rapid acceleration condition as... The endpoint is reached at the moment when the threshold is first exceeded. The voltage returns to below the threshold and the voltage fluctuation amplitude does not exceed ±0.5V for 5 consecutive seconds.

8. A universal lead-acid lithium battery system for low-speed electric vehicles according to claim 5, characterized in that, The battery remaining power calculation module has a pre-calibrated voltage-remaining power characteristic comparison table, which is calibrated through actual vehicle testing based on the correspondence between the discharge voltage and remaining power of a 72V lead-acid battery.

9. A universal lead-acid lithium battery system for low-speed electric vehicles according to claim 5, characterized in that, The specific logic of the voltage anti-jitter processing unit for determining the continuous stability of the voltage value is as follows: record the timestamp of the voltage value entering the current voltage range, and continuously monitor whether the voltage value changes across ranges; if the value in the same voltage range remains unchanged for 60 seconds without changing across ranges, then the voltage value is used as a valid sample value to query the voltage-remaining power characteristic lookup table, obtain the corresponding remaining power value, and update the display; if a change across ranges occurs within 60 seconds, then the timer is reset to zero and the remaining power display value remains unchanged.

10. A universal lead-acid lithium battery system for low-speed electric vehicles according to claim 5, characterized in that, After the rapid acceleration during the uphill climb ends, the ampere-hour integral correction unit adds the remaining power correction amount to the locked remaining power value. The corrected remaining battery power value is generated and fixed as the final display value, which is then output to the display interface of the integrated multimedia instrument. Under subsequent normal driving conditions, the voltage anti-shake processing unit continues to perform voltage lookup table updates based on the corrected remaining battery power value, without retrospectively correcting the display value at the end of the driving condition.

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