A battery pack SOC calculation method and device, electronic equipment and storage medium

Abstract

This invention provides a battery pack SOC calculation method, apparatus, electronic device, and storage medium, relating to the field of battery technology. Based on a DC-DC converter, the high-voltage side of the DC-DC converter is connected to the battery pack, and the low-voltage side of the DC-DC converter is connected to a BMS. The battery pack SOC calculation method includes: acquiring the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period; calculating a first energy consumption based on the high-voltage output current; calculating a second energy consumption based on the high-voltage side current; and determining the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption. This invention effectively improves the accuracy of SOC calculation.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a method, apparatus, electronic device, and storage medium for calculating the state of charge (SOC) of a battery pack. Background Technology

[0002] The state of charge (SOC) of a new energy vehicle battery pack reflects its remaining usable electricity and is a key parameter for users to accurately grasp the driving range and formulate charging plans. Currently, SOC is usually calculated by sampling the battery pack output current through the battery management system (BMS) and based on the ampere-hour integration method.

[0003] However, when the vehicle is powered down (in sleep mode), to reduce power consumption, the BMS typically stops real-time current acquisition and SOC updates, instead relying on empirical models to estimate the SOC, resulting in a significant decrease in accuracy. Meanwhile, some systems intermittently sample and store the output current during power-down using current sensors. Once the vehicle is powered on, these discrete, low-frequency current data are read in a concentrated manner to perform ampere-hour integration to update the SOC. Due to the low sampling frequency and discontinuous timing, this method struggles to accurately capture minute or transient currents (such as static loads and self-discharge), causing accumulated errors in current integration. More seriously, the SOC value often abruptly changes (i.e., "jumps") at the moment of power-on due to this concentrated correction, not only reducing the reliability of the power estimation but also severely impacting the user experience. Summary of the Invention

[0004] The problem addressed by this invention is how to improve the accuracy of battery pack SOC calculation.

[0005] To address the above problems, the present invention provides a battery pack SOC calculation method, apparatus, electronic device, and storage medium.

[0006] In a first aspect, the present invention provides a method for calculating the State of Charge (SOC) of a battery pack, based on a DC-DC converter, wherein the high-voltage end of the DC-DC converter is connected to the battery pack, and the low-voltage end of the DC-DC converter is connected to the Battery Management System (BMS). The method for calculating the SOC of the battery pack includes: Obtain the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period; The first energy consumption is calculated based on the high-voltage output current, and the second energy consumption is calculated based on the high-voltage side current. The SOC value of the battery pack is determined based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

[0007] Optionally, determining the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption includes: The SOC value of the battery pack is obtained by subtracting the first energy consumption and the second energy consumption from the initial energy level.

[0008] Optionally, calculating the first energy consumption based on the high-voltage output current and calculating the second energy consumption based on the high-voltage side current includes: The first energy consumption is calculated based on the high-voltage output current using the ampere-hour integration method. The second energy consumption is calculated based on the high-voltage side current using the ampere-hour integration method.

[0009] Optionally, obtaining the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period includes: Obtain the low-side voltage, low-side current, and high-side voltage of the DC-DC converter; The conversion efficiency of the DC-DC converter is determined based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, wherein the preset correspondence includes the correspondence between the low-voltage side voltage, the high-voltage side voltage, and the conversion efficiency; The high-voltage side current is determined based on the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency.

[0010] Optionally, determining the high-voltage side current based on the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency includes: Determine the first product of the low-voltage side voltage and the low-voltage side current, and the second product of the high-voltage side voltage and the conversion efficiency. Divide the first product and the second product to obtain the high-voltage side current.

[0011] Optionally, before determining the conversion efficiency of the DC-DC converter based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, the method further includes: The conversion efficiency under different operating conditions is determined by calibration, wherein each operating condition includes a set of low-voltage side voltages and high-voltage side voltages; The preset correspondence is established based on the low-voltage side voltage, the high-voltage side voltage, and the corresponding conversion efficiency.

[0012] Optionally, before determining the conversion efficiency of the DC-DC converter based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, the method further includes: The low-voltage side voltage and the high-voltage side voltage are corrected using a predetermined fitting formula.

[0013] Secondly, the present invention provides a battery pack SOC calculation device based on a DC-DC converter, wherein the high-voltage terminal of the DC-DC converter is connected to the battery pack, and the low-voltage terminal of the DC-DC converter is connected to the BMS. The battery pack SOC calculation device includes: The acquisition module is used to acquire the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period. The calculation module is used to calculate a first energy consumption based on the high-voltage output current, and a second energy consumption based on the high-voltage side current; and to determine the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

[0014] Thirdly, the present invention provides an electronic device, including a memory and a processor; The memory is used to store computer programs; The processor is configured to implement the battery pack SOC calculation method as described in the first aspect when executing the computer program.

[0015] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the battery pack SOC calculation method as described in the first aspect.

[0016] The beneficial effects of the battery pack SOC calculation method, apparatus, electronic device, and storage medium of the present invention are as follows: By employing a DC-DC converter to convert the high-voltage DC power of the battery pack into low-voltage DC power, continuous power is supplied to the BMS and the vehicle's low-voltage loads. Since the total energy of the power battery pack is much greater than the energy consumption of the low-voltage loads and the BMS, the BMS can still operate stably for a long time even when the vehicle is powered off, without relying on a sleep / wake-up mechanism. Compared with the existing technology that updates the SOC using discrete, low-frequency stored current data only after the vehicle is powered on, the present invention enables the BMS to continuously and in real-time estimate the battery state throughout the entire life cycle of the vehicle (including the power-off sleep phase), effectively avoiding the cumulative integration error caused by discontinuous current sampling, significantly improving the accuracy of SOC calculation, and effectively reducing the occurrence of SOC jumps at the moment of power-on, thereby improving the user's perception of the remaining battery power. Furthermore, within each sampling period, this invention calculates the corresponding energy consumption based on the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter, respectively: the first energy consumption reflects the total energy output of the high-voltage circuit of the battery pack, such as the energy consumed to drive the vehicle and the energy consumed to charge the small battery; the second energy consumption reflects the energy consumption of the DC-DC converter, as well as the energy consumption of the BMS and low-voltage load connected to the DC-DC converter. Combining the initial charge at the start of the sampling period, and integrating the above two parts of energy consumption, the SOC value of the battery pack is dynamically updated. This invention comprehensively considers the energy flow of the battery pack, achieves accurate tracking of the net discharge of the battery, and further improves the accuracy of SOC calculation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a high-voltage battery pack according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an LDCDC according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating a battery pack SOC calculation method according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a battery pack SOC computing device according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0019] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0021] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] The names of the messages or information exchanged between the multiple devices in the embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0023] In related technologies, new energy vehicles typically use the battery management system (BMS) to calculate the battery pack state of charge (SOC) using the ampere-hour integration method. However, this method requires the BMS to be in normal working condition. For example, after the new energy vehicle starts and is powered on, the BMS samples the output current of the battery pack and then obtains the SOC value through ampere-hour integration.

[0024] However, this method ignores the vehicle's power-off condition. After the vehicle is powered off, to reduce the consumption of the small battery's power, the BMS continues to consume the small battery's energy, potentially causing it to deplete. Therefore, the BMS reduces the current sampling frequency and stores the sampled current for SOC update after the vehicle is powered on. Because the vehicle's power-off condition lasts for a relatively long time, it introduces significant cumulative errors, causing a jump in SOC when the vehicle is powered on. Correspondingly, related technologies calculate the SOC value under the vehicle's power-off condition using empirical models, resulting in poor calculation accuracy.

[0025] To address the problems existing in the aforementioned related technologies, this embodiment provides a battery pack SOC calculation method, apparatus, electronic device, and storage medium.

[0026] like Figure 1 and Figure 2 As shown in the figure, this embodiment of the invention provides a high-voltage battery pack, wherein a DC-DC converter (i.e., LD-DC in the figure) and a BMS can be integrated in the high-voltage battery pack. The high-voltage terminal of the DC-DC converter is connected to the cell module of the high-voltage battery pack. The cell module of the high-voltage battery pack is also used to directly output high voltage. The low-voltage terminal of the DC-DC converter is connected to the BMS.

[0027] Specifically, the low-voltage end of the DC-DC converter can also be connected to low-voltage loads, such as car refrigerators and sentry systems, to convert the high-voltage electricity from the high-voltage battery pack into low-voltage electricity for powering the low-voltage load.

[0028] The DC-DC converter (LDCDC) is powered directly from the high-voltage battery pack, eliminating the need for small batteries such as 12V batteries. During vehicle operation, the LDCDC (Little DirectCurrent to DirectCurrent) can provide redundant power to the BMS. After the vehicle is powered off, it can be used to power scenarios such as sentry mode and refrigerator insulation.

[0029] The high-voltage DC power output from the cell module of the high-voltage battery pack is fed into the LDCDC after passing through the input filter module, and then through two internal circuits: One of the circuits is an auxiliary power supply circuit, which uses a flyback circuit and is then converted to 5V / 3.3V DC power by a low dropout linear regulator (LDO) to power the CAN communication chip, MCU chip, Hall sensor and other chips.

[0030] The other main circuit uses a half-bridge + synchronous rectification circuit topology to convert high-voltage DC (e.g., 400V / 500V) into low-voltage DC (e.g., 12V), which then powers the BMS and low-voltage loads after passing through the output filter module.

[0031] like Figure 3 As shown in the figure, an embodiment of the present invention provides a method for calculating the State of Charge (SOC) of a battery pack, the method comprising: S100, acquire the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period.

[0032] Specifically, the high-voltage output current of the battery pack represents the current output from the battery pack to a high-voltage load, such as for driving a vehicle or for charging a small battery after conversion. The high-voltage side current of the DC-DC converter represents the bus current between the battery pack and the DC-DC converter. Both can be directly acquired by a current sensor. The high-voltage side current of the DC-DC converter can also be calculated from the low-voltage side voltage, low-voltage side current, high-voltage side voltage, and conversion efficiency of the DC-DC converter.

[0033] S200, the first energy consumption is calculated based on the high-voltage output current, and the second energy consumption is calculated based on the high-voltage side current.

[0034] Optionally, calculating the first energy consumption based on the high-voltage output current and calculating the second energy consumption based on the high-voltage side current includes: The first energy consumption is calculated based on the high-voltage output current using the ampere-hour integration method. The second energy consumption is calculated based on the high-voltage side current using the ampere-hour integration method.

[0035] Specifically, the first energy consumption represents the energy consumption corresponding to the high-voltage output of the battery pack, and the second energy consumption represents the energy consumption corresponding to the DC-DC converter, BMS, and low-voltage load.

[0036] S300, determine the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

[0037] Optionally, determining the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption includes: The SOC value of the battery pack is obtained by subtracting the first energy consumption and the second energy consumption from the initial energy level.

[0038] Specifically, SOC(t) = SOC0(t-1) - ΔSOC2(t) - ΔSOC1(t), Where SOC(t) represents the SOC value of the battery pack, and SOC0(t-1) represents the initial SOC value of the battery pack at the start of the current sampling period.

[0039] ΔSOC1(t) represents the first energy consumption in the current sampling period, which can be calculated by the BMS. Under the condition of vehicle power-off, the BMS runs continuously to calculate the energy consumption corresponding to the high voltage output in real time, such as the energy consumption caused by the high voltage battery pack charging the 12V small battery. Compared with estimation based on empirical models, the calculation accuracy is effectively improved.

[0040] ΔSOC2(t) represents the second energy consumption in the current sampling period. Since ΔSOC1(t) does not take into account the actual energy consumption of the DC-DC converter and BMS, as well as the actual energy consumption of the low-voltage load connected to the DC-DC converter, ΔSOC2(t) is obtained by calculating the high-voltage side current. The energy consumption of the DC-DC converter, BMS, and low-voltage load are included in the calculation to improve the accuracy of SOC calculation.

[0041] Where t represents the sampling period or the number of calculation steps, t=0, 1, 2, ... After the battery pack is fully charged, SOC0(0) is reset to 100%.

[0042] ΔSOC1(t) and ΔSOC2(t) are the corresponding ampere-hour integral values, used to characterize the influence of the corresponding ampere-hour integral value on the SOC value.

[0043] In this embodiment, a DC-DC converter is used to convert the high-voltage DC power from the battery pack into low-voltage DC power, continuously supplying power to the BMS and on-board low-voltage loads. Since the total energy of the power battery pack is far greater than the energy consumption of the low-voltage loads and the BMS, the BMS can still operate stably for a long time even when the vehicle is powered off, without relying on a sleep / wake-up mechanism. Compared to existing technologies that only update the State of Charge (SOC) using discrete, low-frequency stored current data after the vehicle is powered on, this embodiment enables the BMS to continuously and in real-time estimate the battery state throughout the entire vehicle lifecycle (including the power-off sleep phase). This effectively avoids the cumulative integration error caused by discontinuous current sampling, significantly improves the accuracy of SOC calculation, and effectively reduces SOC jumps at the moment of power-on, thereby improving the user's perception of remaining battery power. Furthermore, in each sampling period, this invention calculates the corresponding energy consumption based on the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter, respectively: the first energy consumption reflects the total energy output of the high-voltage circuit of the battery pack, such as the energy consumed to drive the vehicle and the energy consumed to charge the small battery; the second energy consumption reflects the energy consumption of the DC-DC converter, as well as the energy consumption of the BMS and low-voltage load connected to the DC-DC converter. Combining the initial charge at the start of the sampling period, the above two parts of energy consumption are integrated to dynamically update the SOC value of the battery pack. This embodiment comprehensively considers the energy flow of the battery pack, realizes accurate tracking of the net discharge of the battery, and further improves the accuracy of SOC calculation.

[0044] Optionally, obtaining the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period includes: Obtain the low-side voltage, low-side current, and high-side voltage of the DC-DC converter; The conversion efficiency of the DC-DC converter is determined based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, wherein the preset correspondence includes the correspondence between the low-voltage side voltage, the high-voltage side voltage, and the conversion efficiency; The high-voltage side current is determined based on the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency.

[0045] Optionally, determining the high-voltage side current based on the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency includes: Determine the first product of the low-voltage side voltage and the low-voltage side current, and the second product of the high-voltage side voltage and the conversion efficiency. Divide the first product and the second product to obtain the high-voltage side current.

[0046] Specifically, based on the law of conservation of energy, a DC-DC converter (i.e. Figure 1 , 2 The conversion model for LDCDC in China is as follows: I hv =(V lv *I lv ) / (η* V hv ), Among them, I hv V represents the high-voltage side current of the DC-DC converter. lv This indicates the low-side voltage of the DC-DC converter, such as Figure 2 As shown, the voltage is measured by the low-voltage side voltage sensor; I lv This represents the low-side current of the DC-DC converter, measured by a low-side current sensor; V hv η represents the high-voltage side voltage of the DC-DC converter, measured by a high-voltage side voltage sensor; η represents the conversion efficiency of the DC-DC converter.

[0047] It should be noted that since high-side voltage, low-side voltage, and low-side current are crucial parameters for ensuring the safe, reliable, and efficient operation of a DC-DC converter, DC-DC converters typically include corresponding sampling circuits to collect these parameters. For example, low-side voltage sampling is used for closed-loop feedback control and overvoltage protection; high-side voltage sampling is used for feedforward compensation and input undervoltage protection; and low-side current sampling is used for load response optimization and overcurrent protection. However, for most DC-DC converters that only require basic voltage regulation and core protection functions, high-side current sampling is not essential. Therefore, DC-DC converters typically do not require corresponding sampling circuits for high-side current acquisition.

[0048] In this optional embodiment, the existing sampling circuit can be used to collect the high-voltage side voltage, low-voltage side voltage and low-voltage side current of the DC-DC converter, and the high-voltage side current can be calculated. There is no need to add a corresponding sampling circuit to collect the high-voltage side current, thereby avoiding the increase in circuit complexity and product cost caused by adding a high-voltage side current sampling circuit.

[0049] Optionally, before determining the conversion efficiency of the DC-DC converter based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, the method further includes: The conversion efficiency under different operating conditions is determined by calibration, wherein each operating condition includes a set of low-voltage side voltages and high-voltage side voltages; The preset correspondence is established based on the low-voltage side voltage, the high-voltage side voltage, and the corresponding conversion efficiency.

[0050] For example, for a set of low-side and high-side voltages corresponding to a certain operating condition, the input of the DC-DC converter to the high-side voltage can be adjusted, the output of the DC-DC converter to the low-side voltage can be adjusted, and the low-side current can be adjusted to a preset value (e.g., the current expected to be used to power the BMS). After the system stabilizes, the corresponding conversion efficiency is obtained based on the conversion efficiency calculation formula. Repeat the calibration to obtain the conversion efficiency corresponding to multiple different operating conditions.

[0051] The low-voltage side voltage, high-voltage side voltage, and conversion efficiency corresponding to each operating condition are associated and stored, for example, by constructing a two-dimensional lookup table. In practical applications, the corresponding conversion efficiency can be obtained by interpolation algorithms based on the collected low-voltage side voltage and high-voltage side voltage.

[0052] In this optional embodiment, a preset correspondence between low-voltage side voltage, high-voltage side voltage and conversion efficiency is established in advance, which facilitates direct lookup during application and improves the calculation efficiency of SOC.

[0053] Optionally, before determining the conversion efficiency of the DC-DC converter based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, the method further includes: The low-voltage side voltage and the high-voltage side voltage are corrected using a predetermined fitting formula.

[0054] Specifically, the fitting formula can be y=kx+b, where y represents the corrected parameters, x represents the original parameters, and k and b are pre-calibrated parameter values. Substituting the low-voltage side voltage and high-voltage side voltage into the corresponding fitting formulas, the corrected low-voltage side voltage and the corrected high-voltage side voltage can be obtained.

[0055] Set the high-voltage side voltage to the maximum input design voltage and operate at 50% load (i.e., output current is 50% of maximum output current). Step-by-step set the low-voltage side voltage to {minimum output design voltage / }. / / Maximum output design voltage}, where and The voltage is evenly distributed between the minimum and maximum output design voltages, and the low-voltage side voltage (i.e., sampled value, x_lv) collected by the BMS and the measured value (i.e., actual value, y_lv) are detected each time.

[0056] Set the low-voltage side voltage to the rated value, operate at 50% load, and distribute the high-voltage side voltage to {minimum input design voltage / }. / / Maximum input design voltage}, where and The voltage is evenly distributed between the minimum and maximum input design voltages, and the high-voltage side voltage (i.e., sampled value, x_hv) and the instrument measured value (i.e., actual value, y_hv) are collected by the BMS each time.

[0057] Based on the values ​​of each sampled value x and the actual value y, the k and b values ​​of the fitted curve (y=kx+b) are calculated using a single curve fitting method (least squares method). The k and b values ​​of the high-voltage side voltage and the low-voltage side voltage are obtained respectively, thus determining the corresponding fitting formula y=kx+b.

[0058] Furthermore, fitting formulas corresponding to high-voltage output current and high-voltage side current can be established in advance, and the high-voltage output current and high-voltage side current can be corrected using the fitting formulas.

[0059] In this optional embodiment, when the BMS directly acquires the high-voltage side voltage and low-voltage side voltage of the DC-DC converter via the bus, the data acquired by the BMS is corrected by fitting the formula, which can effectively compensate for the sampling deviation of the sampling circuit, improve the sampling accuracy, and thus improve the calculation accuracy of the SOC.

[0060] like Figure 4 As shown, an embodiment of the present invention provides a battery pack SOC computing device 400, based on a DC-DC converter. The high-voltage terminal of the DC-DC converter is connected to the battery pack, and the low-voltage terminal of the DC-DC converter is connected to the BMS. The battery pack SOC computing device 400 includes: The acquisition module 410 is used to acquire the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period. The calculation module 420 is used to calculate a first energy consumption based on the high-voltage output current, and a second energy consumption based on the high-voltage side current; and to determine the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

[0061] In this embodiment, a DC-DC converter is used to convert the high-voltage DC power from the battery pack into low-voltage DC power, continuously supplying power to the BMS and on-board low-voltage loads. Since the total energy of the power battery pack is far greater than the energy consumption of the low-voltage loads and the BMS, the BMS can still operate stably for a long time even when the vehicle is powered off, without relying on a sleep / wake-up mechanism. Compared to existing technologies that only update the State of Charge (SOC) using discrete, low-frequency stored current data after the vehicle is powered on, this embodiment enables the BMS to continuously and in real-time estimate the battery state throughout the entire vehicle lifecycle (including the power-off sleep phase). This effectively avoids the cumulative integration error caused by discontinuous current sampling, significantly improves the accuracy of SOC calculation, and effectively reduces SOC jumps at the moment of power-on, thereby improving the user's perception of remaining battery power. Furthermore, in each sampling period, this invention calculates the corresponding energy consumption based on the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter, respectively: the first energy consumption reflects the total energy output of the high-voltage circuit of the battery pack, such as the energy consumed to drive the vehicle and the energy consumed to charge the small battery; the second energy consumption reflects the energy consumption of the DC-DC converter, as well as the energy consumption of the BMS and low-voltage load connected to the DC-DC converter. Combining the initial charge at the start of the sampling period, the above two parts of energy consumption are integrated to dynamically update the SOC value of the battery pack. This embodiment comprehensively considers the energy flow of the battery pack, realizes accurate tracking of the net discharge of the battery, and further improves the accuracy of SOC calculation.

[0062] Optionally, the calculation module 420 is specifically used to: subtract the first energy consumption and the second energy consumption from the initial energy level to obtain the SOC value of the battery pack.

[0063] Optionally, the calculation module 420 is further configured to: calculate the first energy consumption based on the high-voltage output current using the ampere-hour integration method; and calculate the second energy consumption based on the high-voltage side current using the ampere-hour integration method.

[0064] Optionally, the acquisition module is specifically used to: acquire the low-voltage side voltage, low-voltage side current, and high-voltage side voltage of the DC-DC converter; determine the conversion efficiency of the DC-DC converter according to the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, wherein the preset correspondence includes the correspondence between the low-voltage side voltage, the high-voltage side voltage, and the conversion efficiency; and determine the high-voltage side current according to the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency.

[0065] Optionally, the acquisition module is further configured to: determine a first product of the low-voltage side voltage and the low-voltage side current, and a second product of the high-voltage side voltage and the conversion efficiency, and divide the first product by the second product to obtain the high-voltage side current.

[0066] Optionally, the battery pack SOC computing device further includes a calibration module, which is used to: determine the conversion efficiency under different operating conditions through calibration, wherein each operating condition includes a set of low-voltage side voltages and high-voltage side voltages; and establish the preset correspondence based on the low-voltage side voltages, the high-voltage side voltages and the corresponding conversion efficiencies.

[0067] Optionally, the battery pack SOC calculation device further includes a correction module, which is used to correct the low-voltage side voltage and the high-voltage side voltage using a predetermined fitting formula.

[0068] like Figure 5 As shown, an electronic device 500 provided in this embodiment of the invention includes a memory 510 and a processor 520; the memory 510 is used to store a computer program; the processor 520 is used to implement the battery pack SOC calculation method as described above when the computer program is executed.

[0069] Alternatively, an electronic device 500 includes a memory 510 and a processor 520 coupled to the memory 510; the memory 510 is configured to store a computer program; and the processor 520 is configured to perform the following operations when the computer program is executed: Obtain the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period; The first energy consumption is calculated based on the high-voltage output current, and the second energy consumption is calculated based on the high-voltage side current. The SOC value of the battery pack is determined based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

[0070] Specifically, the electronic device can adopt the BMS found in new energy vehicles.

[0071] This invention provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the battery pack SOC calculation method described above.

[0072] Alternatively, a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the following operations: Obtain the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period; The first energy consumption is calculated based on the high-voltage output current, and the second energy consumption is calculated based on the high-voltage side current. The SOC value of the battery pack is determined based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

[0073] Electronic device 500, which can serve as a server or client of the present invention, is described below as an example of a hardware device applicable to various aspects of the present invention. Electronic device 500 is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic device 500 can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0074] Electronic device 500 includes a computing unit that can perform various appropriate actions and processes based on a computer program stored in read-only memory (ROM) or a computer program loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The computing unit, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0075] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc. In this application, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention according to actual needs. Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated units can be implemented in hardware or as software functional units.

[0076] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for calculating the State of Charge (SOC) of a battery pack, characterized in that, Based on a DC-DC converter, the high-voltage side of the DC-DC converter is connected to the battery pack, and the low-voltage side of the DC-DC converter is connected to the BMS. The battery pack SOC calculation method includes: Obtain the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period; The first energy consumption is calculated based on the high-voltage output current, and the second energy consumption is calculated based on the high-voltage side current. The SOC value of the battery pack is determined based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

2. The battery pack SOC calculation method according to claim 1, characterized in that, The step of determining the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption includes: The SOC value of the battery pack is obtained by subtracting the first energy consumption and the second energy consumption from the initial energy level.

3. The battery pack SOC calculation method according to claim 1, characterized in that, The calculation of the first energy consumption based on the high-voltage output current and the calculation of the second energy consumption based on the high-voltage side current include: The first energy consumption is calculated based on the high-voltage output current using the ampere-hour integration method. The second energy consumption is calculated based on the high-voltage side current using the ampere-hour integration method.

4. The battery pack SOC calculation method according to claim 1, characterized in that, The process of obtaining the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period includes: Obtain the low-side voltage, low-side current, and high-side voltage of the DC-DC converter; The conversion efficiency of the DC-DC converter is determined based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, wherein the preset correspondence includes the correspondence between the low-voltage side voltage, the high-voltage side voltage, and the conversion efficiency; The high-voltage side current is determined based on the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency.

5. The battery pack SOC calculation method according to claim 4, characterized in that, Determining the high-voltage side current based on the low-voltage side voltage, the low-voltage side current, the high-voltage side voltage, and the conversion efficiency includes: Determine the first product of the low-voltage side voltage and the low-voltage side current, and the second product of the high-voltage side voltage and the conversion efficiency. Divide the first product and the second product to obtain the high-voltage side current.

6. The battery pack SOC calculation method according to claim 4, characterized in that, Before determining the conversion efficiency of the DC-DC converter based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, the method further includes: The conversion efficiency under different operating conditions is determined by calibration, wherein each operating condition includes a set of low-voltage side voltages and high-voltage side voltages; The preset correspondence is established based on the low-voltage side voltage, the high-voltage side voltage, and the corresponding conversion efficiency.

7. The battery pack SOC calculation method according to claim 4, characterized in that, Before determining the conversion efficiency of the DC-DC converter based on the low-voltage side voltage, the high-voltage side voltage, and a preset correspondence, the method further includes: The low-voltage side voltage and the high-voltage side voltage are corrected using a predetermined fitting formula.

8. A battery pack SOC computing device, characterized in that, Based on a DC-DC converter, the high-voltage side of the DC-DC converter is connected to the battery pack, and the low-voltage side of the DC-DC converter is connected to the BMS. The battery pack SOC computing device includes: The acquisition module is used to acquire the high-voltage output current of the battery pack and the high-voltage side current of the DC-DC converter during the current sampling period. The calculation module is used to calculate a first energy consumption based on the high-voltage output current, and a second energy consumption based on the high-voltage side current; and to determine the SOC value of the battery pack based on the initial charge of the battery pack at the start of the current sampling period, the first energy consumption, and the second energy consumption.

9. An electronic device, characterized in that, Including memory and processor; The memory is used to store computer programs; The processor is configured to implement the battery pack SOC calculation method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the battery pack SOC calculation method as described in any one of claims 1 to 7.

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