A real-time residual power estimation method and device for an electric fork truck

Abstract

The application discloses a kind of real-time residual capacity estimation method and device of electric fork truck, belong to electric fork truck technical field, comprising: the initial theoretical voltage-capacity array under each working condition is obtained by segmenting the full voltage interval of battery, and the weighted sum is obtained theoretical voltage-capacity array;The measured voltage of battery is comprehensively deduced by the charge-discharge capacity in charge-discharge experiment, and the segmented node number of theoretical voltage-capacity array is taken as the segmentation reference, and the measured voltage of battery is segmented to obtain actual voltage-capacity array;Based on the actual voltage value of battery, theoretical voltage-capacity array, actual voltage-capacity array and capacity aging compensation value, obtain capacity jump judgment factor;According to capacity jump judgment factor, obtain next real-time residual capacity.The technical problem that the prior art is difficult to improve the accuracy of capacity jump judgment factor, resulting in low accuracy of residual capacity estimation.

Description

Technical Field

[0001] This invention relates to the field of electric forklift technology, specifically to a method and device for estimating the real-time remaining power of an electric forklift. Background Technology

[0002] In the electric forklift industry, the main types of batteries used are lead-acid and lithium batteries. Lithium-ion electric forklifts typically use CAN communication to transmit the remaining battery power to the forklift's power meter, with the real-time battery power acquisition and calculation primarily handled by the battery protection board. As batteries age, their lifespan and health status decrease, their characteristics change, and their capacity shrinks. The battery protection board struggles to accurately measure the impact of battery lifespan and health status on remaining battery power; therefore, high-precision hardware is required to improve accuracy. Common methods for estimating the remaining power of lead-acid batteries include open-circuit voltage, coulomb counter, and impedance tracking methods, but these generally suffer from high hardware costs and insufficient estimation accuracy. To improve the accuracy of remaining power estimation while effectively controlling the cost of acquiring remaining power for electric forklifts, some existing technologies use a single voltage threshold array as the basis for power level jump judgment. This involves comparing the real-time collected battery voltage with this single threshold array to determine if a power level jump has occurred. However, this method relies on a single threshold for judgment, which is susceptible to voltage fluctuations and has poor reliability. In addition, it does not consider the impact of battery aging on the power jump judgment, resulting in insufficient accuracy of the power jump judgment factor and large error in the remaining power estimation, making it difficult to meet the actual use needs of electric forklifts under complex working conditions. Summary of the Invention

[0003] To address the technical problem of low accuracy in remaining battery estimation due to the inability of existing technologies to improve the accuracy of battery level jump judgment factors, this invention provides a method and device for real-time remaining battery estimation of electric forklifts. The method involves comprehensively retrieving the measured battery voltage from the charge and discharge quantities observed in a charge-discharge experiment, obtaining an actual voltage-charge array, combining this with a theoretical voltage-charge array and a battery aging compensation value to obtain a battery level jump judgment factor, and then using this factor to determine the next real-time remaining battery level. This solves the technical problem of low accuracy in remaining battery estimation caused by the inability of existing technologies to improve the accuracy of the battery level jump judgment factor.

[0004] To address the aforementioned technical problems, this invention provides a method for estimating the real-time remaining power of an electric forklift, comprising the following steps: The battery's full voltage range is segmented to obtain the initial theoretical voltage-capacity array under each operating condition, and the initial theoretical voltage-capacity array is weighted and summed to obtain the theoretical voltage-capacity array; The measured voltage of the battery is derived by comprehensively analyzing the charge and discharge capacity in the charge and discharge experiment. The measured voltage of the battery is then segmented based on the number of nodes in the theoretical voltage-capacity array to obtain the actual voltage-capacity array. Based on the actual battery voltage, the power jump judgment factor is obtained by combining the theoretical voltage-power array, the actual voltage-power array, and the power aging compensation value. The remaining battery level is determined based on the battery level jump factor.

[0005] Preferably, the step of segmenting the battery's full voltage range to obtain the initial theoretical voltage-capacity array for each operating condition includes: The full voltage range is determined with the theoretical voltage value when the battery is fully charged and the theoretical voltage value when the battery is discharged to the cutoff point as the upper and lower boundaries, respectively. The first segment interval is determined based on the battery's rated voltage level. The full voltage range is then segmented according to the first segment interval to obtain the full-charge range, stable range, and low-voltage range. Based on the estimation accuracy requirements and the load size under each operating condition, the second segmentation interval of the full-charge interval, stable interval and low-voltage interval under each operating condition is determined. In this way, the full-charge interval, stable interval and low-voltage interval under each operating condition are segmented to obtain the first initial theoretical voltage-electricity array of the full-charge interval, the second initial theoretical voltage-electricity array of the stable interval and the third initial theoretical voltage-electricity array of the low-voltage interval under each operating condition. The operating conditions include at least light load-no-load alternating conditions, full load-no-load alternating conditions, and half load-no-load alternating conditions.

[0006] Preferably, the step of obtaining the theoretical voltage-energy array by weighted summation of the initial theoretical voltage-energy array includes: The current offset coefficient is obtained based on the battery's maximum allowable charge and discharge cycles and the battery's historical cumulative charge and discharge cycles. The temperature compensation value is obtained based on the preset temperature compensation curve and the battery's historical temperature. The battery's historical discharge current and historical voltage are also obtained. The historical discharge current is corrected based on the current offset coefficient and temperature compensation value, and the voltage drop value is obtained based on the historical voltage. Based on the corrected historical discharge current and voltage drop values, the cumulative duration of each operating condition is calculated. The weight of each operating condition is obtained according to the cumulative duration. The initial theoretical voltage-energy array is then weighted and summed according to the weight of each operating condition to obtain the theoretical voltage-energy array.

[0007] In this scheme, considering that the battery discharge capacity is weaker at low temperatures and the discharge current is smaller under the same load, while the battery internal resistance decreases at high temperatures and the discharge current is larger under the same load, and considering that the battery capacity decays and output capacity decreases with cycle use, which will further cause the current characteristics to deviate from the original characteristics, in order to eliminate the interference of temperature and aging on the identification of operating conditions, the historical discharge current is corrected based on the current offset coefficient and temperature compensation value. Considering that the voltage drop of aged batteries is more significant under the same load current, while that of new batteries is relatively stable, in order to avoid misjudging the heavy load of aged batteries as the light load of new batteries, thus leading to incorrect identification of operating conditions, the corrected historical discharge current and voltage drop value are combined to obtain the cumulative operating time of each operating condition. By improving the accuracy of operating condition identification, the accuracy of the cumulative operating time is significantly improved, thereby improving the accuracy of the theoretical voltage-capacity array.

[0008] Preferably, the step of comprehensively reversing the measured voltage of the battery through the charge and discharge capacity in the charge and discharge experiment, and segmenting the measured voltage of the battery to obtain the actual voltage-capacity array based on the number of segmentation nodes of the theoretical voltage-capacity array, includes: After discharging the battery to the rated termination voltage, the battery is charged, and the correlation between the charging measurement voltage and the actual charge of the battery at each moment is recorded. When the battery is fully charged, the actual charge of the battery is divided into equal intervals based on the number of segment nodes of the theoretical voltage-charge array to obtain the actual charge array of the battery. The first actual voltage-charge array is obtained based on the actual charge array and the correlation. Discharge the fully charged battery and record the discharge measurement voltage corresponding to the charge element in the actual charge array to obtain the second actual voltage-charge array; The smaller voltage element at the corresponding position in the first actual voltage-energy array and the second actual voltage-energy array is selected to obtain the actual voltage-energy array.

[0009] In this scheme, by selecting the smaller value at the corresponding position of the first actual voltage-capacity array and the second actual voltage-capacity array, the actual voltage-capacity array is constructed. This effectively weakens the voltage difference caused by the battery's charge and discharge hysteresis characteristics, making the actual voltage-capacity array more closely match the electrical characteristics of the battery under actual discharge conditions, thereby improving the reliability and accuracy of the actual voltage-capacity array.

[0010] Preferred options also include: Obtain the reset voltage value when the battery is fully charged. If the actual battery voltage value is greater than or equal to the reset voltage value, the current real-time remaining power is 100%. If it is less than the reset voltage value and there is a voltage value stored before the power outage, the current real-time remaining power is obtained based on the voltage value stored before the power outage. If it is less than the reset voltage value and there is no voltage value stored before the power outage, the current real-time remaining power is obtained based on the actual battery voltage value and the theoretical voltage-power array.

[0011] Preferably, before obtaining the power jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-power array, the actual voltage-power array, and the power aging compensation value, the method further includes: The fitting coefficient is obtained based on the fitting curve of the battery's depth of discharge and cycle life. The equivalent cycle life is obtained based on the ratio of the battery's cumulative usage time since the start of use to the battery's typical discharge time and the fitting coefficient. An aging correction factor is obtained based on the equivalent cycle life and the cycle life of the electric forklift under half load. An energy aging compensation value is obtained based on the aging correction factor and the cycle life of the electric forklift under full load.

[0012] This scheme obtains the fitting coefficient by fitting the relationship between the depth of discharge and the cycle life, and calculates the equivalent cycle life by combining the ratio of cumulative usage time to typical discharge time. Then, based on the cycle life under different operating conditions, it obtains the aging correction coefficient and the charge aging compensation value. This can comprehensively reflect the impact of usage time, depth of discharge and operating load on battery aging, and more accurately characterize the actual degradation characteristics of the battery, thereby improving the rationality and accuracy of the charge aging compensation value.

[0013] Preferably, the step of obtaining the power jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-power array, the actual voltage-power array, and the power aging compensation value, includes: Based on the actual battery voltage, the voltage deviation accumulation factor and static loss compensation factor are obtained by combining the theoretical voltage-capacity array and the actual voltage-capacity array. The power jump judgment factor is obtained based on the voltage deviation accumulation factor, static loss compensation factor, and power aging compensation value.

[0014] This solution calculates a voltage deviation accumulation factor by combining theoretical voltage-capacity arrays and actual voltage-capacity arrays. This effectively distinguishes between the actual battery discharge behavior and instantaneous interference such as load fluctuations and voltage spikes, avoiding the problem of fluctuating battery level displays caused by frequent voltage jitters near the threshold. Simultaneously, the static loss compensation factor obtained based on the theoretical and actual voltage-capacity arrays can adaptively correct for battery static loss, improving the shortcomings of lag in battery level display and large estimation errors in low-voltage areas, making the remaining battery level calculation more closely match the actual battery discharge characteristics. Furthermore, by introducing a battery aging compensation value, it can effectively compensate for voltage deviations caused by battery capacity decay and increased internal resistance, ensuring that both new and aged batteries maintain high estimation accuracy, improving the adaptability and operational reliability of the instrument system throughout the battery's entire lifespan. Finally, the fusion of voltage deviation statistics, static loss compensation, and battery aging correction to obtain a battery level jump judgment factor significantly improves the accuracy and robustness of battery level jump judgment.

[0015] Preferably, the step of obtaining the voltage deviation accumulation factor and static loss compensation factor based on the actual battery voltage value, combined with the theoretical voltage-capacity array and the actual voltage-capacity array, includes: The voltage deviation accumulation factor is obtained by calculating the cumulative number of times the actual voltage value of the battery is less than the corresponding voltage element in the theoretical voltage-capacity array and the cumulative number of times the actual voltage value of the battery is greater than the corresponding voltage element in the actual voltage-capacity array. The average voltage is obtained by comparing the voltage elements in the theoretical voltage-capacity array with the voltage elements in the actual voltage-capacity array. The static loss compensation factor is then obtained by combining the actual voltage value of the battery with the static loss current based on the cumulative number of times the actual voltage value is less than the average voltage value.

[0016] Preferably, obtaining the next real-time remaining battery power based on the battery power jump judgment factor includes: If the battery level jump judgment factor is less than or equal to the preset factor, then the current real-time remaining battery level will be used as the next real-time remaining battery level. If the power jump judgment factor is greater than the preset factor, then the next remaining power of the current real-time remaining power will be taken as the next real-time remaining power.

[0017] By adopting the above technical solution, the present invention has the following advantages: The measured battery voltage is derived by comprehensively analyzing the charge and discharge quantities in charge and discharge experiments, and an actual voltage-capacity array is obtained. This array is then combined with the theoretical voltage-capacity array and the capacity aging compensation value to obtain a capacity jump judgment factor. Based on this factor, the next real-time remaining capacity is calculated. This solves the technical problem of existing technologies struggling to improve the accuracy of the capacity jump judgment factor, leading to low accuracy in remaining capacity estimation. Specifically, by combining the theoretical voltage-capacity array and the actual voltage-capacity array to calculate the voltage deviation accumulation factor, the system can effectively distinguish between the actual battery discharge behavior and instantaneous interference such as load fluctuations and voltage spikes, avoiding the problem of fluctuating battery level display caused by frequent voltage jitters near the threshold. Simultaneously, the static loss compensation factor obtained based on the theoretical and actual voltage-capacity arrays can adaptively correct for battery static loss, improving the shortcomings of lag in battery level display and large estimation deviations in low-voltage areas, making the remaining battery level calculation more closely match the actual battery discharge characteristics. Furthermore, by introducing a battery aging compensation value, the system can effectively compensate for voltage deviations caused by battery capacity decay and increased internal resistance, ensuring that both new and aged batteries maintain high estimation accuracy, and improving the adaptability and operational reliability of the instrument system throughout the battery's entire lifespan. Finally, by integrating voltage deviation statistics, static loss compensation, and battery aging correction to obtain the battery level jump judgment factor, the accuracy and robustness of battery level jump judgment are significantly improved.

[0018] This invention also provides a real-time remaining power estimation device for electric forklifts, applicable to the aforementioned real-time remaining power estimation method for electric forklifts, comprising: The theoretical voltage-capacity array construction module is used to segment the entire voltage range of the battery to obtain the initial theoretical voltage-capacity array under each operating condition, and to perform a weighted summation of the initial theoretical voltage-capacity array to obtain the theoretical voltage-capacity array. The actual voltage-capacity array construction module is used to deduce the measured voltage of the battery by comprehensively reversing the charge and discharge capacity in the charge and discharge experiment, and to obtain the actual voltage-capacity array by segmenting the measured voltage of the battery based on the number of segment nodes of the theoretical voltage-capacity array. The battery level jump judgment factor acquisition module is used to obtain the battery level jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-battery level array, the actual voltage-battery level array, and the battery aging compensation value. The next real-time remaining power acquisition module is used to obtain the next real-time remaining power based on the power jump judgment factor.

[0019] By adopting the above technical solution, the present invention has the following advantages: By comprehensively analyzing the charge and discharge volumes from charging and discharging experiments, the measured battery voltage is derived, and an actual voltage-capacity array is obtained. This array, combined with the theoretical voltage-capacity array and the capacity aging compensation value, yields a capacity jump-off judgment factor. Based on this factor, the next real-time remaining capacity is calculated. This approach solves the technical problem of existing technologies struggling to improve the accuracy of the capacity jump-off judgment factor, leading to low accuracy in remaining capacity estimation. Attached Figure Description

[0020] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. The drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0021] Figure 1 This is a flowchart illustrating a method for estimating the real-time remaining power of an electric forklift according to the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only one preferred embodiment of this invention and are only used to explain this invention. They do not limit the scope of protection of this invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations (or steps) can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but it may also have additional steps not included in the figures; the process may correspond to a method, function, procedure, subroutine, subroutine, etc.

[0024] Example 1: like Figure 1 As shown, a method for estimating the real-time remaining power of an electric forklift includes the following steps: S1: Divide the battery's full voltage range into segments to obtain the initial theoretical voltage-capacity array under each operating condition, and perform a weighted summation of the initial theoretical voltage-capacity array to obtain the theoretical voltage-capacity array.

[0025] As an optional embodiment, the step of segmenting the battery's full voltage range to obtain the initial theoretical voltage-capacity array under each operating condition includes: The full voltage range is determined with the theoretical voltage value when the battery is fully charged and the theoretical voltage value when the battery is discharged to the cutoff point as the upper and lower boundaries, respectively. The first segment interval is determined based on the battery's rated voltage level. The full voltage range is then segmented according to the first segment interval to obtain the full-charge range, stable range, and low-voltage range. Based on the estimation accuracy requirements and the load size under each operating condition, the second segmentation interval of the full-charge interval, stable interval and low-voltage interval under each operating condition is determined. In this way, the full-charge interval, stable interval and low-voltage interval under each operating condition are segmented to obtain the first initial theoretical voltage-electricity array of the full-charge interval, the second initial theoretical voltage-electricity array of the stable interval and the third initial theoretical voltage-electricity array of the low-voltage interval under each operating condition. The operating conditions include at least light load-no-load alternating conditions, full load-no-load alternating conditions, and half load-no-load alternating conditions.

[0026] Understandably, the higher the battery's rated voltage level, the larger the first segment interval. In this embodiment, the first segment interval is preferably 1, and the fully charged range is... The stable interval is The low-pressure area is , This represents the theoretical voltage value when the battery is fully charged. Indicates the first segment interval. This represents the theoretical voltage value at which the battery discharges to its cutoff point. Understandably, the higher the required estimation accuracy, the smaller the second segment interval; the greater the load under each operating condition, the larger the second segment interval. The load under alternating full-load and no-load conditions, half-load and no-load conditions, and light-load and no-load conditions decrease sequentially, and the second segment interval decreases sequentially accordingly. The first initial theoretical voltage-charge array is... , This indicates the number of segments in the fully charged range under each operating condition; here it is 3. This represents the second segment interval of the fully charged range under each operating condition. The second initial theoretical voltage-charge array is... , This indicates the number of segments in the stability interval under each operating condition; here it is 14. The second segment interval represents the stable range under each operating condition, and the third initial theoretical voltage-electrical quantity array is... , This indicates the number of segments in the low-pressure range under each operating condition; here it is 3. This indicates the second segment interval of the low-voltage range under various operating conditions. By dividing the entire battery voltage into 20 segments, the relationship between battery voltage and remaining battery capacity can be preliminarily obtained, which is equivalent to dividing the total battery capacity into 20 segments, with each segment decreasing by approximately 5% of the capacity. This applies to full-load-no-load alternating conditions, half-load-no-load alternating conditions, and light-load-no-load alternating conditions. + + The sums are equal.

[0027] As an optional embodiment, the step of obtaining the theoretical voltage-energy array by weighted summation of the initial theoretical voltage-energy array includes: The current offset coefficient is obtained based on the battery's maximum allowable charge and discharge cycles and the battery's historical cumulative charge and discharge cycles. The temperature compensation value is obtained based on the preset temperature compensation curve and the battery's historical temperature. The battery's historical discharge current and historical voltage are also obtained. The historical discharge current is corrected based on the current offset coefficient and temperature compensation value, and the voltage drop value is obtained based on the historical voltage. Based on the corrected historical discharge current and voltage drop values, the cumulative duration of each operating condition is calculated. The weight of each operating condition is obtained according to the cumulative duration. The initial theoretical voltage-energy array is then weighted and summed according to the weight of each operating condition to obtain the theoretical voltage-energy array.

[0028] Understandably, the preset temperature compensation curve is a temperature-temperature compensation value correspondence curve obtained through pre-calibration via battery charge-discharge experiments. It characterizes the impact of different ambient temperatures on the actual discharge capacity of the battery. This temperature compensation curve uses ambient temperature as the independent variable and the temperature compensation value as the dependent variable, where the temperature compensation value is the ratio of the battery's actual discharge capacity at different temperatures to its discharge capacity at room temperature. In low-temperature environments, the battery's discharge capacity weakens, and the temperature compensation value is less than 1. In normal-temperature environments, the battery's discharge capacity is consistent with its nominal capacity, and the temperature compensation value is equal to 1. In high-temperature environments, the battery's discharge capacity increases, and the temperature compensation value is greater than 1. Through the preset temperature compensation curve, the corresponding temperature compensation value can be obtained based on the battery's current historical temperature, eliminating the interference caused by temperature changes on discharge current detection and operating condition identification, thereby improving the accuracy of operating condition identification.

[0029] The expression for obtaining the corrected historical discharge current is: , This represents the corrected historical discharge current at the k-th sampling time. This represents the historical discharge current at the k-th sampling time. Indicates the current offset coefficient. This indicates the temperature compensation value. The cumulative operating time under light load conditions. m represents the total number of samples. This represents the sampling duration at the k-th sampling time (e.g., if the single sampling interval is 0.1h, then...). ), This indicates an indicator function (1 if the condition is true, 0 if the condition is false). This indicates the upper limit threshold of current under light load conditions. This represents the voltage drop at the k-th sampling time. This indicates the upper limit threshold for voltage sag under light load conditions. The cumulative duration of operation under half load conditions. , This indicates the upper limit threshold of the current under half-load conditions. This indicates the upper limit threshold of voltage drop under half-load conditions and the cumulative duration of full-load conditions. The cumulative duration of light-load conditions is used as the weight for light-load-no-load alternating conditions, the cumulative duration of half-load conditions is used as the weight for half-load-no-load alternating conditions, and the cumulative duration of full-load conditions is used as the weight for full-load-no-load alternating conditions.

[0030] Understandably, the expression for the theoretical voltage-electricity array is: ; Represents the theoretical voltage-electrical quantity array. This indicates the weight of the alternating full-load and no-load operating conditions. This indicates the weight of the half-load-no-load alternating operating condition. This indicates the weight of the light load-no-load alternating operating condition. , and These represent the initial theoretical voltage-energy arrays under alternating full-load and no-load conditions, the initial theoretical voltage-energy arrays under alternating half-load and no-load conditions, and the initial theoretical voltage-energy arrays under alternating light-load and no-load conditions, respectively. It is understandable that the theoretical voltage-energy array represents the correspondence between the theoretical voltage and the remaining energy.

[0031] This embodiment takes into account that the battery's discharge capacity is weaker at low temperatures, resulting in a smaller discharge current under the same load, while the battery's internal resistance decreases at high temperatures, leading to a larger discharge current under the same load. Considering that battery capacity decays and output capacity decreases with cycle use, further deviating the original current characteristics, the historical discharge current is corrected based on the current offset coefficient and temperature compensation value, thereby eliminating the interference of temperature and aging on operating condition identification. Considering that the voltage drop is more significant for aged batteries and relatively stable for new batteries under the same load current, the corrected historical discharge current and voltage drop value are combined to obtain the cumulative operating time for each operating condition. This avoids misjudging the heavy load of aged batteries as the light load of new batteries, thus preventing operating condition identification errors. By improving the accuracy of operating condition identification, the accuracy of the cumulative operating time is significantly improved, thereby improving the accuracy of the theoretical voltage-capacity array.

[0032] S2: The measured voltage of the battery is derived by comprehensively analyzing the charge and discharge capacity in the charge and discharge experiment. The measured voltage of the battery is then segmented based on the number of nodes in the theoretical voltage-capacity array to obtain the actual voltage-capacity array.

[0033] As an optional embodiment, the method of comprehensively reversing the measured voltage of the battery through the charge and discharge capacity in the charge and discharge experiment, and obtaining the actual voltage-capacity array by segmenting the measured voltage of the battery using the number of segment nodes in the theoretical voltage-capacity array as the segmentation benchmark, includes: After discharging the battery to the rated termination voltage, the battery is charged, and the correlation between the charging measurement voltage and the actual charge of the battery at each moment is recorded. When the battery is fully charged, the actual charge of the battery is divided into equal intervals based on the number of segment nodes of the theoretical voltage-charge array to obtain the actual charge array of the battery. The first actual voltage-charge array is obtained based on the actual charge array and the correlation. Discharge the fully charged battery and record the discharge measurement voltage corresponding to the charge element in the actual charge array to obtain the second actual voltage-charge array; The smaller voltage element at the corresponding position in the first actual voltage-energy array and the second actual voltage-energy array is selected to obtain the actual voltage-energy array.

[0034] Understandably, the actual voltage-charge array represents the correspondence between the actual voltage and the remaining charge. The rated termination voltage specifically refers to the lower limit of safe discharge voltage specified in the battery manufacturer's datasheet or industry standards.

[0035] Because the battery undergoes a process of polarization voltage decay and terminal voltage gradually recovering to open-circuit voltage after discharge stops, it is necessary to stop discharging and allow the battery to stand still for 3-5 minutes before recording the discharge measurement voltage corresponding to the charge element in the actual charge array. This allows the battery voltage to fully recover and stabilize before voltage acquisition. By allowing the voltage to stabilize before acquisition, the influence of factors such as load polarization and instantaneous voltage drop on the measurement results can be effectively eliminated, thus significantly improving the accuracy and reliability of the discharge measurement voltage. Furthermore, this embodiment constructs an actual voltage-charge array by selecting the smaller value at corresponding positions in the first and second actual voltage-charge arrays. This effectively weakens the voltage difference caused by the battery's charge-discharge hysteresis characteristics, making the actual voltage-charge array more closely reflect the electrical characteristics of the battery under actual discharge conditions, thereby improving the reliability and accuracy of the actual voltage-charge array.

[0036] S3: Based on the actual battery voltage value, the power jump judgment factor is obtained by combining the theoretical voltage-power array, the actual voltage-power array, and the power aging compensation value.

[0037] In some embodiments, it also includes: Obtain the reset voltage value when the battery is fully charged. If the actual battery voltage value is greater than or equal to the reset voltage value, the current real-time remaining power is 100%. If it is less than the reset voltage value and there is a voltage value stored before the power outage, the current real-time remaining power is obtained based on the voltage value stored before the power outage. If it is less than the reset voltage value and there is no voltage value stored before the power outage, the current real-time remaining power is obtained based on the actual battery voltage value and the theoretical voltage-power array.

[0038] Understandably, after the battery is fully charged, it needs to remain idle for 15 days before the reset voltage value is obtained. When the actual battery voltage is greater than or equal to the reset voltage, the LED displays a full charge with 10 divisions. When the actual voltage is less than the reset voltage, and a voltage value stored before the power outage exists, the current real-time remaining charge is obtained based on the stored voltage value and displayed on the LED. When the actual voltage is less than the reset voltage, and no voltage value stored before the power outage exists, the actual battery voltage is compared with the theoretical voltage value in the theoretical voltage-charge array to locate the corresponding charge range and obtain the current real-time remaining charge.

[0039] In other embodiments, before obtaining the power jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-power array, the actual voltage-power array, and the power aging compensation value, the method further includes: The fitting coefficient is obtained based on the fitting curve of the battery's depth of discharge and cycle life. The equivalent cycle life is obtained based on the ratio of the battery's cumulative usage time since the start of use to the battery's typical discharge time and the fitting coefficient. An aging correction factor is obtained based on the equivalent cycle life and the cycle life of the electric forklift under half load. An energy aging compensation value is obtained based on the aging correction factor and the cycle life of the electric forklift under full load.

[0040] In this embodiment, the expression for the fitted curve is: , Indicates cycle life. and All represent the fitting coefficients. This indicates the depth of discharge. For example, the datasheet specifies a cycle life of over 600 cycles at 75% depth of discharge and over 1000 cycles at 50% depth of discharge. The cycle life can be calculated using a fitted curve. and The expression for the battery aging compensation value is: , This indicates the battery aging compensation value. This indicates the cycle life of an electric forklift under full load. This indicates the cumulative usage time of the battery since it was first used. This indicates the typical discharge time of the battery. Typical discharge time is the standard discharge duration of the battery under factory-calibrated conditions. Specifically, it is the time consumed for the battery to discharge to the specified cutoff voltage at a constant current using the standard calibrated discharge rate when it is fully charged. For lithium iron phosphate batteries, the standard discharge rate is usually 0.2c (where c is the total battery capacity); for lead-acid batteries, a 10-hour rate discharge rate is usually used as the typical discharge condition. This indicates the cycle life of an electric forklift under half load. This indicates the equivalent cycle life. As a battery is used for longer periods, its health deteriorates, its characteristics change, its capacity decreases, and the voltage fluctuations vary significantly. Its main function is to compensate for the battery's health status during its lifespan. This solution obtains the fitting coefficient by fitting the relationship between the depth of discharge and cycle life, and calculates the equivalent cycle life by combining the ratio of cumulative usage time to typical discharge time. Then, based on the cycle life under different operating conditions, it obtains the aging correction coefficient and the charge aging compensation value. This can comprehensively reflect the impact of usage time, depth of discharge, and operating load on battery aging, more accurately characterize the actual degradation characteristics of the battery, and thus improve the rationality and accuracy of the charge aging compensation value.

[0041] In some embodiments, obtaining the battery level jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-capacity array, the actual voltage-capacity array, and the capacity aging compensation value, includes: Based on the actual battery voltage, the voltage deviation accumulation factor and static loss compensation factor are obtained by combining the theoretical voltage-capacity array and the actual voltage-capacity array. The power jump judgment factor is obtained based on the voltage deviation accumulation factor, static loss compensation factor, and power aging compensation value.

[0042] Specifically, the step of obtaining the voltage deviation accumulation factor and static loss compensation factor based on the actual battery voltage value, combined with the theoretical voltage-capacity array and the actual voltage-capacity array, includes: The voltage deviation accumulation factor is obtained by calculating the cumulative number of times the actual voltage value of the battery is less than the corresponding voltage element in the theoretical voltage-capacity array and the cumulative number of times the actual voltage value of the battery is greater than the corresponding voltage element in the actual voltage-capacity array. The average voltage is obtained by comparing the voltage elements in the theoretical voltage-capacity array with the voltage elements in the actual voltage-capacity array. The static loss compensation factor is then obtained by combining the actual voltage value of the battery with the static loss current based on the cumulative number of times the actual voltage value is less than the average voltage value.

[0043] Understandably, the voltage elements in each energy level stage of the theoretical voltage-energy level array are lower than the voltage elements in the corresponding stages of the actual voltage-energy level array. The expression for obtaining the voltage deviation accumulation factor is: , This indicates the voltage deviation cumulative factor. This represents the voltage element in the theoretical voltage-capacity array. Specifically, it refers to the theoretical voltage value corresponding to the actual battery voltage value obtained from the theoretical voltage-capacity array. For example, if the battery's actual voltage value A displays a capacity of 50% at a certain moment, and the corresponding voltage value for 50% capacity in the theoretical voltage-capacity array is B, then the theoretical voltage value corresponding to the actual battery voltage value A obtained from the theoretical voltage-capacity array at this time is B. N represents the length of the theoretical voltage-capacity array. This represents the actual voltage value at the i-th sampling time, where T represents the total number of sampling times. The sampling interval can be flexibly set according to actual needs. This represents the voltage element corresponding to the actual voltage-capacity array. Specifically, it refers to the actual voltage value corresponding to the battery's actual voltage value obtained from the actual voltage-capacity array. For example, if the battery's actual voltage value C displays a capacity of 40% at a certain moment, and the voltage value corresponding to 40% capacity in the actual voltage-capacity array is D, then the actual voltage value corresponding to the battery's actual voltage value C obtained from the actual voltage-capacity array at this time is D. Since the theoretical voltage-capacity array and the actual voltage-capacity array have the same length, N can also represent the length of the actual voltage-capacity array. The expression for obtaining the static loss compensation factor is: ; This represents the static loss compensation factor. This represents the static loss current, which is the current when the electric forklift is powered on but stationary under no-load conditions. This indicates the rated capacity of the battery used in the electric forklift. This represents the sampling frequency of the actual voltage value. The expression for obtaining the power switching judgment factor is: ; This indicates the factor that determines whether the battery level will change.

[0044] By combining the theoretical voltage-capacity array and the actual voltage-capacity array to calculate the voltage deviation accumulation factor, the true discharge trend of the battery can be effectively distinguished from instantaneous interference such as load changes and voltage spikes, avoiding misjudgments in the battery level display caused by repeated voltage fluctuations around a single threshold. When using a single threshold: if the voltage fluctuates around the voltage element line, if it is lower than the voltage element, the accumulation is increased by 1; if it is higher than the voltage element, no action is taken and the value is not reset. If it is lower than the voltage element again, the accumulation is increased by 1 again; if it is higher than the voltage element again, no action is taken. Eventually, the longer the fluctuation lasts, the larger the accumulated value becomes, eventually forcing a jump in the battery level, but the actual battery level remains unchanged. In this embodiment, by constructing a two-way judgment interval using the theoretical threshold and the actual threshold, invalid accumulations caused by small voltage fluctuations around the threshold can be filtered out. Effective statistics are only performed when the voltage shows a continuous and true deviation trend, thus ensuring a more stable and reliable battery level jump judgment. Meanwhile, based on the static loss compensation factor obtained from the theoretical voltage-capacity array and the actual voltage-capacity array, the static loss of the battery can be adaptively corrected, improving the shortcomings of lag in power display and large estimation deviation in low-voltage areas, making the remaining power calculation more consistent with the actual discharge characteristics of the battery. Furthermore, by introducing a power aging compensation value, voltage deviations caused by battery capacity decay and increased internal resistance can be effectively compensated, ensuring that both new and aged batteries maintain high estimation accuracy, and improving the adaptability and operational reliability of the instrument system throughout the battery's entire lifespan. Finally, the voltage deviation statistics, static loss compensation, and power aging correction are integrated to obtain the power jump judgment factor, significantly improving the accuracy and robustness of power jump judgment.

[0045] S4: Obtain the next real-time remaining battery level based on the battery level jump judgment factor.

[0046] Specifically, obtaining the next real-time remaining battery power based on the battery power jump judgment factor includes: If the battery level jump judgment factor is less than or equal to the preset factor, then the current real-time remaining battery level will be used as the next real-time remaining battery level. If the power jump judgment factor is greater than the preset factor, then the next remaining power of the current real-time remaining power will be taken as the next real-time remaining power.

[0047] Understandably, if the battery level jump judgment factor is less than or equal to the preset factor, the remaining battery level display does not need to jump downwards; if the battery level jump judgment factor is greater than the preset factor, the remaining battery level display should jump downwards. Understandably, to improve the accuracy of subsequent remaining battery level acquisition, when the battery level jump judgment factor is less than or equal to the preset factor, the actual voltage value needs to be continuously acquired, and the battery level jump judgment factor is accumulated to obtain the remaining battery level for subsequent moments. When the battery level jump judgment factor is greater than the preset factor, the battery level jump judgment factor is obtained based on the newly acquired actual battery voltage value, combined with the theoretical voltage-battery level array, the actual voltage-battery level array, and the newly acquired battery aging compensation value. The remaining battery level for subsequent moments is then obtained based on the battery level jump judgment factor. The preset factor can be flexibly set according to requirements.

[0048] Example 2: This embodiment also provides a real-time remaining power estimation device for electric forklifts, applicable to the aforementioned real-time remaining power estimation method for electric forklifts, including: The theoretical voltage-capacity array construction module is used to segment the entire voltage range of the battery to obtain the initial theoretical voltage-capacity array under each operating condition, and to perform a weighted summation of the initial theoretical voltage-capacity array to obtain the theoretical voltage-capacity array. The actual voltage-capacity array construction module is used to deduce the measured voltage of the battery by comprehensively reversing the charge and discharge capacity in the charge and discharge experiment, and to obtain the actual voltage-capacity array by segmenting the measured voltage of the battery based on the number of segment nodes of the theoretical voltage-capacity array. The battery level jump judgment factor acquisition module is used to obtain the battery level jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-battery level array, the actual voltage-battery level array, and the battery aging compensation value. The next real-time remaining power acquisition module is used to obtain the next real-time remaining power based on the power jump judgment factor.

[0049] Understandably, this device is installed on an electric forklift. The LED instrument on the forklift displays the remaining battery power and the forklift's cumulative running time through 10 segments. In the 10-segment LED power display driver circuit, LED1 represents an integrated module containing 10 independent LEDs. Led_sel1 to Led_sel10 represent the cathodes of the LEDs, controlled by the MCU or driver chip. When a pin is pulled low, the corresponding LED lights up. R is a common current-limiting resistor connected to the +5V power supply to provide current to all LEDs and prevent damage due to overcurrent. The operation is as follows: the MCU lights up the corresponding LED segment by sequentially pulling low different Led_sel pins. For example, pulling low Led_sel1 and Led_sel2 will light up the first two LED segments, indicating that the battery power is approximately 20%.

[0050] The specific embodiments described above are preferred embodiments of the real-time remaining power estimation method and device for electric forklifts of the present invention, and are not intended to limit the specific scope of the present invention. The scope of the present invention includes but is not limited to the specific embodiments described above. All equivalent changes made in accordance with the shape and structure of the present invention are within the protection scope of the present invention.

Claims

1. A method for estimating the real-time remaining power of an electric forklift, characterized in that, Includes the following steps: The battery's full voltage range is segmented to obtain the initial theoretical voltage-capacity array under each operating condition, and the initial theoretical voltage-capacity array is weighted and summed to obtain the theoretical voltage-capacity array; The measured voltage of the battery is derived by comprehensively analyzing the charge and discharge capacity in the charge and discharge experiment. The measured voltage of the battery is then segmented based on the number of nodes in the theoretical voltage-capacity array to obtain the actual voltage-capacity array. Based on the actual battery voltage, the power jump judgment factor is obtained by combining the theoretical voltage-power array, the actual voltage-power array, and the power aging compensation value. The remaining battery level is obtained based on the battery level jump judgment factor; The battery level jump judgment factor is obtained based on the actual battery voltage value, combined with the theoretical voltage-capacity array, the actual voltage-capacity array, and the capacity aging compensation value, including: Based on the actual battery voltage, the voltage deviation accumulation factor and static loss compensation factor are obtained by combining the theoretical voltage-capacity array and the actual voltage-capacity array. The power jump judgment factor is obtained based on the voltage deviation accumulation factor, static loss compensation factor, and power aging compensation value. The process of obtaining the voltage deviation accumulation factor and static loss compensation factor based on the actual battery voltage value, combined with the theoretical voltage-capacity array and the actual voltage-capacity array, includes: The voltage deviation accumulation factor is obtained by calculating the cumulative number of times the actual voltage value of the battery is less than the corresponding voltage element in the theoretical voltage-capacity array and the cumulative number of times the actual voltage value of the battery is greater than the corresponding voltage element in the actual voltage-capacity array. The average voltage is obtained by comparing the voltage elements in the theoretical voltage-capacity array with the voltage elements in the actual voltage-capacity array. The static loss compensation factor is then obtained by combining the actual voltage value of the battery with the static loss current based on the cumulative number of times the actual voltage value is less than the average voltage value.

2. The method for estimating the real-time remaining power of an electric forklift according to claim 1, characterized in that, The step of segmenting the battery's full voltage range to obtain the initial theoretical voltage-capacity array under each operating condition includes: The full voltage range is determined with the theoretical voltage value when the battery is fully charged and the theoretical voltage value when the battery is discharged to the cutoff point as the upper and lower boundaries, respectively. The first segment interval is determined based on the battery's rated voltage level. The full voltage range is then segmented according to the first segment interval to obtain the full-charge range, stable range, and low-voltage range. Based on the estimation accuracy requirements and the load size under each operating condition, the second segmentation interval of the full-charge interval, stable interval and low-voltage interval under each operating condition is determined. In this way, the full-charge interval, stable interval and low-voltage interval under each operating condition are segmented to obtain the first initial theoretical voltage-electricity array of the full-charge interval, the second initial theoretical voltage-electricity array of the stable interval and the third initial theoretical voltage-electricity array of the low-voltage interval under each operating condition. The operating conditions include at least light load-no-load alternating conditions, full load-no-load alternating conditions, and half load-no-load alternating conditions.

3. The method for estimating the real-time remaining power of an electric forklift according to claim 1, characterized in that, The step of obtaining the theoretical voltage-energy array by weighted summation of the initial theoretical voltage-energy array includes: The current offset coefficient is obtained based on the battery's maximum allowable charge and discharge cycles and the battery's historical cumulative charge and discharge cycles. The temperature compensation value is obtained based on the preset temperature compensation curve and the battery's historical temperature. The battery's historical discharge current and historical voltage are also obtained. The historical discharge current is corrected based on the current offset coefficient and temperature compensation value, and the voltage drop value is obtained based on the historical voltage. Based on the corrected historical discharge current and voltage drop values, the cumulative duration of each operating condition is calculated. The weight of each operating condition is obtained according to the cumulative duration. The initial theoretical voltage-energy array is then weighted and summed according to the weight of each operating condition to obtain the theoretical voltage-energy array.

4. The method for estimating the real-time remaining power of an electric forklift according to claim 1, characterized in that, The measured voltage of the battery is derived by comprehensively analyzing the charge and discharge quantities in the charge and discharge experiment. Using the number of segmented nodes in the theoretical voltage-capacity array as the segmentation benchmark, the measured voltage of the battery is segmented to obtain the actual voltage-capacity array, including: After discharging the battery to the rated termination voltage, the battery is charged, and the correlation between the charging measurement voltage and the actual charge of the battery at each moment is recorded. When the battery is fully charged, the actual charge of the battery is divided into equal intervals based on the number of segment nodes of the theoretical voltage-charge array to obtain the actual charge array of the battery. The first actual voltage-charge array is obtained based on the actual charge array and the correlation. Discharge the fully charged battery and record the discharge measurement voltage corresponding to the charge element in the actual charge array to obtain the second actual voltage-charge array; The smaller voltage element at the corresponding position in the first actual voltage-energy array and the second actual voltage-energy array is selected to obtain the actual voltage-energy array.

5. The method for estimating the real-time remaining power of an electric forklift according to claim 1, characterized in that, Also includes: Obtain the reset voltage value when the battery is fully charged. If the actual battery voltage value is greater than or equal to the reset voltage value, the current real-time remaining power is 100%. If it is less than the reset voltage value and there is a voltage value stored before the power outage, the current real-time remaining power is obtained based on the voltage value stored before the power outage. If it is less than the reset voltage value and there is no voltage value stored before the power outage, the current real-time remaining power is obtained based on the actual battery voltage value and the theoretical voltage-power array.

6. The method for estimating the real-time remaining power of an electric forklift according to claim 1, characterized in that, Before obtaining the battery level jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-capacity array, the actual voltage-capacity array, and the capacity aging compensation value, the following steps are also included: The fitting coefficient is obtained based on the fitting curve of the battery's depth of discharge and cycle life. The equivalent cycle life is obtained based on the ratio of the battery's cumulative usage time since the start of use to the battery's typical discharge time and the fitting coefficient. An aging correction factor is obtained based on the equivalent cycle life and the cycle life of the electric forklift under half load. An energy aging compensation value is obtained based on the aging correction factor and the cycle life of the electric forklift under full load.

7. The method for estimating the real-time remaining power of an electric forklift according to claim 1, characterized in that, The step of obtaining the next real-time remaining battery power based on the battery power jump judgment factor includes: If the battery level jump judgment factor is less than or equal to the preset factor, then the current real-time remaining battery level will be used as the next real-time remaining battery level. If the power jump judgment factor is greater than the preset factor, then the next remaining power of the current real-time remaining power will be taken as the next real-time remaining power.

8. A device for estimating the real-time remaining power of an electric forklift, applicable to the method for estimating the real-time remaining power of an electric forklift as described in any one of claims 1-7, characterized in that, include: The theoretical voltage-capacity array construction module is used to segment the entire voltage range of the battery to obtain the initial theoretical voltage-capacity array under each operating condition, and to perform a weighted summation of the initial theoretical voltage-capacity array to obtain the theoretical voltage-capacity array. The actual voltage-capacity array construction module is used to deduce the measured voltage of the battery by comprehensively reversing the charge and discharge capacity in the charge and discharge experiment, and to obtain the actual voltage-capacity array by segmenting the measured voltage of the battery based on the number of segment nodes of the theoretical voltage-capacity array. The battery level jump judgment factor acquisition module is used to obtain the battery level jump judgment factor based on the actual battery voltage value, combined with the theoretical voltage-battery level array, the actual voltage-battery level array, and the battery aging compensation value. The next real-time remaining power acquisition module is used to obtain the next real-time remaining power based on the power jump judgment factor.

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