Method for determining state of charge of battery, voltameter, battery system and electronic equipment

Abstract

The invention relates to the technical field of battery management, in particular to a battery charge state determination method, a voltameter, a battery system and electronic equipment. The method for determining the state of charge of the battery comprises the steps that after the battery enters a tail end discharging state, the smooth residual capacity value at the next moment is continuously predicted according to the smooth residual capacity value at the current moment, and due to the fact that the prediction period is generally short, and the temperature value and the load value of the battery during discharging are both small in change, the state of charge of the battery is determined. The influence of the temperature value and the load size of the battery on the internal resistance can be ignored, and the smooth residual capacity value of the battery is calculated for two adjacent times, so that the influence of the internal resistance of the battery on the calculated smooth residual capacity value is offset, and the calculated smooth residual capacity value of the battery and the load voltage of the battery maintain a one-to-one correspondence relationship; the accuracy of the monitored state of charge of the battery is ensured, and the condition that the state of charge of the battery directly jumps to zero at the discharge tail end of the battery is also avoided.

Description

Technical Field

[0001] The present application relates to the field of battery management technology, and in particular to a method for determining a battery state of charge, a fuel meter, a battery system, and an electronic device. Background Art

[0002] Battery systems are widely used in technical fields such as smart terminals, portable power supplies, and electric vehicles. During the operation of a battery system, it is usually necessary to monitor the remaining chemical capacity of the battery in real time through a fuel gauge. In other words, the fuel gauge tracks and monitors the battery's State of Charge (SOC) so that users can promptly understand the remaining chemical capacity of the battery.

[0003] In the related art, during the battery discharge process, it is assumed that when the battery reaches the cutoff voltage during discharge, the actual remaining capacity value of the battery will also reach zero synchronously. Then, when the battery starts to discharge, the battery internal resistance is calculated using the battery internal resistance model. Based on the calculated battery internal resistance, the battery internal resistance model is used to simulate and calculate the remaining capacity value of the battery under different load voltages. Then, the battery state of charge is updated based on the remaining capacity value calculated by simulation. However, in actual working scenarios, the internal resistance of the battery will change due to changes in the current operating temperature and load size of the battery. Therefore, when calculating the battery state of charge using existing simulation methods, the battery remaining capacity value will usually not reach zero synchronously when the battery load voltage reaches the cutoff voltage. This will cause the battery state of charge to jump directly to zero at the end of battery discharge, thereby affecting the accuracy of the monitored battery state of charge. Summary of the Invention

[0004] The present application provides a method for determining the state of charge of a battery, a fuel meter, a battery system, and an electronic device to solve the technical problem in the related art that the state of charge of the battery directly jumps to zero at the end of battery discharge, thereby affecting the accuracy of the monitored state of charge of the battery.

[0005] In a first aspect, the present application provides a method for determining a battery state of charge, the method comprising: After determining that the battery has entered a terminal discharge state, obtaining discharge parameter information of the battery at a current moment, and determining a first depth of discharge of the battery according to the discharge parameter information of the battery at a current moment; the discharge parameter information of the battery at a current moment includes: a current loaded voltage value, a current discharge temperature value, and a current discharge current value; obtaining a cutoff voltage of the battery, and determining a second depth of discharge corresponding to when the battery reaches the cutoff voltage according to a current discharge temperature value, a current discharge current value, and the cutoff voltage of the battery; determining a predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge, and determining a predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtaining a smoothed remaining capacity value of the battery at a current moment, and determining a unit discharge capacity of the battery per unit time based on the smoothed remaining capacity value at a current moment and the predicted remaining discharge time; determining a smoothed remaining capacity value of the battery at a next moment according to the smoothed remaining capacity value of the battery at a current moment and the unit discharge capacity; The state of charge of the battery is determined according to the smoothed remaining capacity value of the battery at the next moment and the full charge capacity value of the battery.

[0006] In one possible design, determining whether the battery enters a terminal discharge state includes: During the battery discharge process, determining the remaining capacity of the battery, and when it is determined that the remaining capacity of the battery is less than or equal to a preset remaining capacity, determining that the battery enters a terminal discharge state; Alternatively, during the battery discharge process, the loaded voltage value of the battery is determined, and when it is determined that the loaded voltage value of the battery is less than or equal to a preset voltage value, it is determined that the battery enters a terminal discharge state.

[0007] In one possible design, determining the first depth of discharge of the battery according to the current discharge parameter information of the battery includes: Obtain an equivalent circuit model of the battery; According to the equivalent circuit model of the battery, a first depth of discharge of the battery at a current moment is determined according to the current loaded voltage value, the current discharge temperature value, and the current discharge current value of the battery.

[0008] In one possible design, obtaining the cutoff voltage of the battery and determining, according to a current discharge temperature value, a current discharge current value, and the cutoff voltage of the battery, a second depth of discharge corresponding to when the battery reaches the cutoff voltage includes: Using the current discharge temperature value as the discharge temperature value corresponding to when the battery reaches the cut-off voltage, and using the current discharge current value as the discharge current value corresponding to when the battery reaches the cut-off voltage; According to an equivalent circuit model of the battery, the second depth of discharge corresponding to when the battery reaches the cut-off voltage is determined according to the cut-off voltage and the discharge temperature value and discharge current value corresponding to when the cut-off voltage is reached.

[0009] In one possible design, determining the predicted discharge capacity of the battery according to the first depth of discharge and the second depth of discharge includes: Obtaining the maximum chemical capacity of the battery; The predicted discharge capacity of the battery when the battery reaches the cut-off voltage from a current moment is determined according to the maximum chemical capacity of the battery, the first discharge depth, and the second discharge depth.

[0010] In one possible design, obtaining the smoothed remaining capacity value of the battery at a current moment includes: Determine the remaining capacity value corresponding to when the battery enters the terminal discharge state as the initial smoothed remaining capacity value; After the battery enters the terminal discharge state, the smoothed residual capacity value of the battery at the current moment is determined to be the smoothed residual capacity value at the previous moment minus the discharged power of the battery from the previous moment to the current moment.

[0011] In a second aspect, the present application further provides a battery fuel meter, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the program, the steps of the method for determining the battery state of charge as described in any one of the above items are implemented.

[0012] In a third aspect, the present application also provides a battery system, which includes a battery fuel meter as provided in any of the above items.

[0013] In a fourth aspect, the present application also provides an electronic device, which includes a battery fuel meter as provided in any one of the above items; or the electronic device includes the battery system as described above.

[0014] In a fifth aspect, the present application further provides a computer-readable storage medium storing a computer program, which executes any of the above-mentioned methods for determining the battery state of charge when running on a processor.

[0015] The method for determining the battery state of charge provided by the first aspect above first obtains discharge parameter information of the battery at the current moment after determining that the battery has entered a terminal discharge state, and determines a first depth of discharge of the battery based on the discharge parameter information of the battery at the current moment; obtains the cutoff voltage of the battery, and determines a second depth of discharge corresponding to when the battery reaches the cutoff voltage based on the current discharge temperature value, the current discharge current value, and the cutoff voltage of the battery; then determines a predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge, and determines a predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtains a smoothed remaining capacity value of the battery at the current moment, and determines the unit discharge capacity of the battery per unit time based on the smoothed remaining capacity value at the current moment and the predicted remaining discharge time; determines a smoothed remaining capacity value of the battery at the next moment based on the smoothed remaining capacity value of the battery at the current moment and the unit discharge capacity; and finally determines the battery state of charge based on the smoothed remaining capacity value of the battery at the next moment and the full charge capacity value of the battery. In this way, after the battery enters the terminal discharge state, it is equivalent to continuously predicting the smoothed remaining capacity value at the next moment based on the smoothed remaining capacity value at the current moment. Since the prediction period is generally short, the temperature value and load size of the battery during discharge change very little, so the influence of the battery temperature value and load size on the internal resistance can be ignored. In addition, the smoothed remaining capacity value of the battery is calculated twice in an adjacent manner, which offsets the influence of the battery internal resistance on the calculated smoothed remaining capacity value, so that the calculated smoothed remaining capacity value of the battery and the loaded voltage of the battery maintain a one-to-one correspondence, thereby ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge directly jumps to zero at the end of battery discharge.

[0016] The beneficial effects provided in the above-mentioned other aspects and the possible designs of the above-mentioned other aspects can be referred to the beneficial effects brought about by the above-mentioned first aspect and the possible implementation methods of the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of a method for determining a battery state of charge according to an embodiment of the present application; Figure 2 A schematic diagram showing the relationship between discharge depth and load voltage provided in an embodiment of the present application; Figure 3 A schematic diagram of the battery fuel meter structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a alone, b alone, or c alone can mean: a alone, b alone, c alone, a and b combined, a and c combined, b and c combined, or a, b, and c combined, where a, b, and c can be single or plural. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0019] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present application.

[0020] The terms "connected" and "connect" should be interpreted broadly. For example, "connected" or "connected" in a circuit structure can refer not only to a physical connection, but also to an electrical connection or a signal connection. For example, it can be a direct connection, i.e., a physical connection, or an indirect connection through at least one intermediate component, as long as the circuit is interconnected. It can also refer to internal connectivity between two components. Signal connection can refer not only to signal connection through circuits but also to signal connection through media, such as radio waves. Those skilled in the art will understand the specific meanings of the above terms in this application on a case-by-case basis.

[0021] The following is an introduction to the nouns involved in this application: The State of Charge (SOC) is used to reflect the remaining capacity of the battery and the percentage of battery power.

[0022] The internal resistance of a battery refers to the resistance encountered by current flowing through the battery when the battery is working. The internal resistance of a battery changes over time during the charging and discharging process because the composition of the active material, the concentration of the electrolyte, and the temperature are constantly changing.

[0023] Open Circuit Voltage (OCV) is the difference between the positive electrode potential and the negative electrode potential when the battery is disconnected (that is, when no current passes through the two poles).

[0024] Depth of discharge (DOD) refers to the percentage of power removed from the battery to its rated capacity.

[0025] A battery's remaining capacity (RM) refers to the maximum charge the battery can discharge in its current state until it reaches the final discharge voltage. The final discharge voltage, also known as the cutoff voltage or cutoff voltage, refers to the minimum operating voltage at which the battery can no longer be discharged.

[0026] Full Charge Capacity (FCC) refers to the maximum amount of electricity that can be released after the battery is fully charged.

[0027] In related technologies, during the battery discharge process, it is assumed that when the battery reaches the cut-off voltage during discharge, the actual remaining capacity of the battery will also reach zero simultaneously. Then, when the battery starts to discharge, the battery internal resistance is calculated using a battery internal resistance model. Based on the calculated battery internal resistance, the battery internal resistance model is used to simulate and calculate the remaining capacity of the battery at different load voltages. The battery state of charge is then updated based on the simulated remaining capacity value. Specifically, when the battery system is initially powered on, the battery's full charge capacity and the remaining battery capacity are sampled as a reference. Then, during the battery operation process, the battery internal resistance is calculated based on the battery internal resistance model, and the remaining battery capacity is calculated by simulation using current integration. The battery state of charge is then determined based on the simulated remaining battery capacity value. However, in actual working scenarios, the internal resistance of the battery will change due to changes in the current operating temperature and load size of the battery, while the internal resistance of the battery calculated by the battery internal resistance model is fixed. Therefore, there is a certain difference between the internal resistance of the battery calculated by the battery internal resistance model and the internal resistance of the battery during actual operation. As a result, when the battery state of charge is calculated using existing simulation methods, the remaining capacity value of the battery usually does not reach zero synchronously when the battery's loaded voltage reaches the cut-off voltage. As a result, the battery state of charge will directly jump to zero at the end of battery discharge, thereby affecting the accuracy of the monitored battery state of charge.

[0028] In order to overcome the deficiencies in the above-mentioned related technologies, the present application provides a method for determining the state of charge of a battery. First, after determining that the battery has entered a terminal discharge state, the discharge parameter information of the battery at the current moment is obtained, and a first depth of discharge of the battery is determined based on the discharge parameter information of the battery at the current moment; the cut-off voltage of the battery is obtained, and a second depth of discharge corresponding to when the battery reaches the cut-off voltage is determined based on the current discharge temperature value, the current discharge current value, and the cut-off voltage of the battery; then, a predicted discharge capacity of the battery is determined based on the first depth of discharge and the second depth of discharge, and a predicted remaining discharge time of the battery is determined based on the current discharge current value and the predicted discharge capacity; the smoothed remaining capacity value of the battery at the current moment is obtained, and the unit discharge capacity of the battery per unit time is determined based on the smoothed remaining capacity value and the predicted remaining discharge time; the smoothed remaining capacity value of the battery at the next moment is determined based on the smoothed remaining capacity value and the unit discharge capacity of the battery; and finally, the state of charge of the battery is determined based on the smoothed remaining capacity value and the full charge capacity value of the battery at the next moment. In this way, after the battery enters the terminal discharge state, it is equivalent to continuously predicting the smoothed remaining capacity value at the next moment based on the smoothed remaining capacity value at the current moment. Since the prediction period is generally short, the temperature value and load size of the battery during discharge change very little, so the influence of the battery temperature value and load size on the internal resistance can be ignored. In addition, the smoothed remaining capacity value of the battery is calculated twice in an adjacent manner, which offsets the influence of the battery internal resistance on the calculated smoothed remaining capacity value, so that the calculated smoothed remaining capacity value of the battery and the loaded voltage of the battery maintain a one-to-one correspondence, thereby ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge directly jumps to zero at the end of battery discharge.

[0029] Figure 1 For a flow chart of the method for determining the battery state of charge provided in the embodiment of the present application, please refer to Figure 1 As shown, the method for determining the battery state of charge provided in this embodiment includes: S101. After determining that the battery has entered a terminal discharge state, obtain discharge parameter information of the battery at a current moment, and determine a first depth of discharge of the battery based on the discharge parameter information of the battery at the current moment; the discharge parameter information of the battery at the current moment includes: a current loaded voltage value, a current discharge temperature value, and a current discharge current value.

[0030] In one embodiment of the present application, the method for determining the battery state of charge also includes: during the battery discharge process, obtaining the remaining capacity or loaded voltage value of the battery in real time, and determining whether the battery enters the terminal discharge state based on the remaining capacity or loaded voltage value.

[0031] In one embodiment of the present application, determining that the battery enters the terminal discharge state specifically includes: during the battery discharge process, determining the remaining capacity of the battery, and when it is determined that the remaining capacity of the battery is less than or equal to a preset remaining capacity, determining that the battery enters the terminal discharge state.

[0032] For example, in one application scenario, the preset remaining capacity of the battery can be set to 100 mAh. During the battery discharge process, when it is determined that the remaining capacity of the battery is less than or equal to 100 mAh, it is determined that the battery enters the terminal discharge state.

[0033] In one embodiment of the present application, determining that the battery enters the terminal discharge state specifically includes: during the battery discharge process, determining the loaded voltage value of the battery, and when it is determined that the loaded voltage value of the battery is less than or equal to a preset voltage value, determining that the battery enters the terminal discharge state.

[0034] For example, in one application scenario, the preset voltage value of the battery can be set to 3.2V, and the cut-off voltage of the battery can be set to 3.1V. Then, during the battery discharge process, when it is determined that the loaded voltage value of the battery is less than 3.2V, it is determined that the battery enters the terminal discharge state.

[0035] In one embodiment of the present application, determining a first depth of discharge of a battery based on discharge parameter information of the battery at a current moment includes: obtaining an equivalent circuit model of the battery; and determining the first depth of discharge of the battery at the current moment based on the equivalent circuit model of the battery and the current loaded voltage value, the current discharge temperature value, and the current discharge current value of the battery.

[0036] Specifically, since there is a one-to-one correspondence between the open circuit voltage (OCV) of the battery and the depth of discharge (DOD) of the battery, according to the internal battery resistance table of the battery system, for a given discharge current I, the zero-order battery model of the battery can be used to obtain the corresponding theoretical load voltage value at a given depth of discharge (DOD) and discharge temperature value, which can be expressed as: V load = OCV(DOD) + I * R(DOD, T) (1) In the above formula (1), V load It represents the loaded voltage value of the battery, DOD represents the depth of discharge of the battery, OCV(DOD) represents the open circuit voltage when the depth of discharge of the battery is DOD, I represents the discharge current value of the battery, T represents the temperature value when the battery is working, and R(DOD, T) represents the internal resistance value when the depth of discharge of the battery is DOD and the operating temperature value of the battery is T.

[0037] According to the equivalent circuit model of the battery shown in the above formula (1), when the battery enters the terminal discharge state, the following relationship expression can be obtained for the current moment: V now =OCV(DOD now )+I now *R(DOD now , T now ) (2) In the above expression, V load Indicates the current load voltage value of the battery at the current moment, DOD now Indicates the first discharge depth of the battery at the current moment, OCV (DOD now ) represents the first depth of discharge (DOD) of the battery at the current moment now The open circuit voltage, I now Indicates the current discharge current value of the battery at the current moment, T now Indicates the current discharge temperature value of the battery, R(DOD now , T now ) indicates that the battery is at the first depth of discharge (DOD) now , and the current discharge temperature value T now The internal resistance value when .

[0038] It can be understood that in the above expression (2), the current load voltage value V load , Current discharge temperature value T now And the current discharge current value I now All of them can be collected and obtained through the battery management system or the corresponding sampling circuit, and then the first depth of discharge value DOD at the current moment can be obtained now .

[0039] S102: Obtain a cut-off voltage of the battery, and determine a second depth of discharge corresponding to when the battery reaches the cut-off voltage according to a current discharge temperature value, a current discharge current value, and the cut-off voltage of the battery.

[0040] It is understandable that the time from when the battery enters the terminal discharge state to when the battery reaches the cut-off voltage is generally short, during which the battery operating temperature and discharge current values change little. Therefore, the current battery operating temperature value T can be used. now And the discharge current value I now As the operating temperature value and discharge current value corresponding to when the battery reaches the cut-off voltage.

[0041] In one embodiment of the present application, based on the above-mentioned inventive concept, according to the equivalent circuit model of the battery shown in the above formula (1), when the battery enters the terminal discharge state, the corresponding relationship between the cut-off voltage of the battery and the second discharge depth can be obtained, which can be specifically expressed as: V term =OCV(DOD term )+I now *R(DOD term, T now )(3) In the above expression (3), V term Indicates the battery's cut-off voltage, DOD term Indicates the second depth of discharge when the battery reaches the cut-off voltage, OCV (DOD term ) represents the open circuit voltage when the battery reaches the cut-off voltage, I now Indicates the current discharge current value of the battery at the current moment, T now Indicates the current discharge temperature value of the battery, R(DOD term , T now ) indicates that the battery is at the second depth of discharge value DOD now , and the current discharge temperature value T now The internal resistance value when .

[0042] It can be seen that according to the above method, when the cut-off voltage V is collected term 、Current load voltage value V load , Current discharge temperature value T now And the current discharge current value I now Then the first depth of discharge value DOD at the current moment is obtained now And the second depth of discharge DOD when the battery reaches the cut-off voltage term .

[0043] S103. Determine a predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge, and determine a predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtain a smoothed remaining capacity value of the battery at the current moment, and determine a unit discharge capacity of the battery per unit time based on the smoothed remaining capacity value at the current moment and the predicted remaining discharge time.

[0044] In one embodiment of the present application, based on the first discharge depth and the second discharge depth of the battery, the predicted discharge capacity Q of the battery can be obtained by combining the maximum chemical capacity Qmax of the battery. cap .

[0045] Specifically, determining the predicted discharge capacity of the battery according to the first discharge depth and the second discharge depth includes: obtaining the maximum chemical capacity of the battery; and determining the predicted discharge capacity of the battery when it reaches the cut-off voltage from the current moment according to the maximum chemical capacity, the first discharge depth, and the second discharge depth.

[0046] Specifically, the predicted discharge capacity of the battery can be obtained according to the following formula: Q cap = Qmax * (DOD term - DOD now )(4) In the above formula (4), Qmax represents the maximum chemical capacity of the battery, Q cap Indicates the predicted discharge capacity of the battery when it reaches the cut-off voltage from the current moment, DOD term Indicates the second depth of discharge value, DOD now Indicates the first depth of discharge value.

[0047] It can be seen that when the first depth of discharge and the second depth of discharge of the battery are calculated according to the above method, since the changes in the discharge current and the discharge temperature of the battery at the end of discharge are very small, the second depth of discharge calculated based on the above method is relatively accurate.

[0048] Furthermore, when the above formula (4) is used to calculate the predicted discharge capacity based on the two discharge depths, the internal resistance of the battery can be offset in theory. This also eliminates the influence of temperature change and discharge current on the internal resistance to a certain extent, making the calculated predicted discharge capacity more accurate.

[0049] Then, the predicted remaining discharge time of the battery is determined based on the current discharge current value and the predicted discharge capacity. Specifically, the predicted remaining discharge time of the battery can be determined using the following formula: S t = Q cap / I now (5) In the above formula (5), S t Indicates the predicted remaining discharge time, Q cap It indicates the predicted discharge capacity of the battery when it reaches the cut-off voltage from the current moment, I now Indicates the current discharge current value of the battery. The current discharge current value of the battery can be used to indicate the discharge rate of the battery.

[0050] Furthermore, the smoothed remaining capacity value of the battery at the current moment is obtained, and the unit discharge capacity of the battery per unit time is determined based on the smoothed remaining capacity value at the current moment and the predicted remaining discharge time.

[0051] It is understandable that in order for the battery to reach the cut-off voltage V term When the battery's state of charge (SOC) reaches zero, the current smoothed remaining capacity (SmoothRM) needs to be calculated in the prediction of the remaining discharge time (S). t If the battery is discharged within a certain time, the unit discharge capacity per unit time can be determined. For example, if the unit time is one second, the battery discharge capacity per second can be expressed as: C=SmoothRM * 3600 / S t (6) In the above formula (6), C represents the discharge capacity of the battery in one second, SmoothRM represents the current smooth remaining capacity of the battery, and St Indicates the predicted remaining discharge time.

[0052] S104: Determine the smoothed remaining capacity value of the battery at the next moment according to the smoothed remaining capacity value of the battery at the current moment and the unit discharge capacity.

[0053] Among them, the interval between the current moment and the next moment can be set according to the actual scenario. For scenarios with relatively high requirements for the state of charge SOC accuracy, the interval between the current moment and the next moment can be set shorter, for example, the interval time is set to one second. For scenarios with general requirements for the state of charge SOC accuracy, the interval between the current moment and the next moment can be set longer, for example, the interval time is set to 2 seconds or 3 seconds.

[0054] In one embodiment of the present application, the remaining capacity value corresponding to when the battery enters the terminal discharge state is determined to be an initial smoothed remaining capacity value. This initial smoothed remaining capacity value can be obtained using existing current integration methods. Since the initial smoothed remaining capacity value obtained using the current integration method is relatively accurate when the battery just enters the terminal discharge state, it can be used as a reference baseline value. After the battery enters the terminal discharge state, the smoothed remaining capacity value of the battery at the current moment is determined to be the smoothed remaining capacity value at the previous moment minus the amount of discharge discharged by the battery from the previous moment to the current moment.

[0055] It is understandable that after the battery enters the terminal discharge state, the smoothed remaining capacity value of the battery at any time can be obtained by taking the initial smoothed remaining capacity value as a reference and subtracting the discharged power of the battery at adjacent moments.

[0056] It is understandable that since the prediction period is generally short, the temperature value and load size of the battery during discharge change very little, so the impact of the battery temperature value and load size on the internal resistance can be ignored, so the calculated smoothed remaining capacity value is also more accurate.

[0057] The smoothed remaining capacity value in this embodiment is relative to the actual remaining capacity value of the battery, that is, the remaining capacity value after smoothing the actual battery capacity value. It can be understood that the remaining capacity value of the battery at any time can be calculated using the above method. For any intermediate time, the remaining capacity value of the battery at two adjacent times can be smoothed to obtain the smoothed remaining capacity value at any time.

[0058] Figure 2 A schematic diagram of the relationship between the discharge depth and the load voltage provided in the embodiment of the present application is shown in FIG. Figure 2 As shown, the horizontal axis represents the discharge depth. Figure 2 It is expressed in DOD, and the vertical axis represents the load voltage value. Figure 2The dotted line represents the OCV voltage curve of the battery, and the solid line below the dotted line represents the loaded voltage V after the discharge current I is added. load The curve, V term Is the discharge cut-off voltage value specified by the battery system. When the load voltage V load Reaching this cut-off voltage V term When the state of charge SOC is 0, the corresponding first discharge depth is DOD. now Indicates. V load Indicates the battery load voltage at the current moment. The corresponding second depth of discharge is DOD. term express.

[0059] S105 : Determine the state of charge of the battery according to the smoothed remaining capacity value of the battery at the next moment and the full charge capacity value of the battery.

[0060] The full charge capacity value of the battery can be obtained based on battery parameters or a battery management system. After obtaining the smoothed remaining capacity value and the full charge capacity value of the battery at the next moment, the battery state of charge can be determined based on the following formula: SmoothSOC = SmoothRM / SmoothFCC (7) Among them, SmoothRM is the smooth remaining capacity of the battery; SmoothFCC is the full charge capacity value of the battery; SmoothSOC is the state of charge of the battery.

[0061] The state of charge can be displayed in the form of percentage, numerical value or schematic diagram, so that the user can intuitively and clearly understand the current state of charge of the battery.

[0062] According to the method provided in this embodiment, after the battery enters the terminal discharge state, it is equivalent to continuously predicting the smoothed remaining capacity value at the next moment based on the smoothed remaining capacity value at the current moment. Since the prediction period is generally short, the temperature value and load size of the battery during discharge change very little, so the influence of the battery temperature value and load size on the internal resistance can be ignored. In addition, the smoothed remaining capacity value of the battery is calculated twice in succession, which offsets the influence of the battery internal resistance on the calculated smoothed remaining capacity value. Therefore, the calculated smoothed remaining capacity value of the battery and the loaded voltage of the battery maintain a one-to-one correspondence, thereby ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge directly jumps to zero at the end of battery discharge.

[0063] Figure 3 For a schematic diagram of the battery fuel gauge structure provided in this application embodiment, please refer to Figure 3As shown, the embodiment of the present application also provides a battery fuel meter, which includes a memory 302 and a processor 301, wherein the memory 302 stores a computer program that can be run on the processor, and when the processor 301 executes the program, the steps of the method for determining the battery state of charge provided in any of the above embodiments are implemented, and the method for determining the battery state of charge includes: after determining that the battery enters the terminal discharge state, obtaining the discharge parameter information of the battery at the current moment, and determining the first discharge depth of the battery according to the discharge parameter information of the battery at the current moment; the discharge parameter information of the battery at the current moment includes: the current loaded voltage value, the current discharge temperature value and the current discharge current value; obtaining the cut-off voltage of the battery, and determining the first discharge depth of the battery according to the current discharge parameter information of the battery The method comprises the following steps: determining a second depth of discharge corresponding to when the battery reaches the cut-off voltage based on a previous discharge temperature value, a current discharge current value, and a cut-off voltage; determining a predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge, and determining a predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtaining a smoothed remaining capacity value of the battery at a current moment, and determining a unit discharge capacity of the battery per unit time based on the smoothed remaining capacity value at a current moment and the predicted remaining discharge time; determining a smoothed remaining capacity value of the battery at a next moment based on the smoothed remaining capacity value of the battery at a current moment and the unit discharge capacity; and determining a state of charge of the battery based on the smoothed remaining capacity value of the battery at a next moment and the full charge capacity value of the battery.

[0064] Optionally, the processor may be a central processing unit (CPU).

[0065] Please continue to see Figure 3 As shown, the battery fuel gauge further includes a voltage and temperature sampling and conversion unit 304 , a current and coulomb integration sampling and conversion unit 305 , a power management unit 306 and a communication unit 303 .

[0066] The voltage and temperature sampling and conversion unit 304 is used to sample the discharge temperature and on-load voltage values of the battery. Specifically, the voltage and temperature sampling and conversion unit 304 includes a voltage sampling circuit 341, a temperature sampling circuit 342, a channel switch 343, and a communication analog-to-digital converter 344. The voltage sampling circuit 341 is used to sample the on-load voltage value, the temperature sampling circuit 342 is used to sample the discharge temperature value, and the communication analog-to-digital converter 344 is used to perform analog-to-digital conversion on the sampled analog on-load voltage value and analog discharge temperature value to obtain digital on-load voltage value and discharge temperature value. The channel switch 343 is used to control the switching of the sampling channel to switch the sampling channel between voltage sampling and temperature sampling.

[0067] The current and coulomb integration sampling and conversion unit 305 may include a current sampling circuit and a coulomb integration analog-to-digital converter. The current sampling circuit is used to sample the charging or discharging current value of the battery, and the coulomb integration analog-to-digital converter is used to sample the sampled battery current, integrate it over time to accumulate the capacity, and output the load current value.

[0068] It should be noted that batteries typically have a charging process and a discharging process. During the charging process, the Coulomb integrating ADC is used to sample the input battery charging current and integrate it over time to accumulate the charging capacity. The output load current value is the charging current value. During the discharging process, the Coulomb integrating ADC is used to sample the input battery discharge current and integrate it over time to accumulate the discharge capacity. The output load current value (i.e., the discharge current value) is used.

[0069] The memory 302 is used to store the battery internal resistance table R (DOD, T), the open circuit voltage table OCV (DOD), the cut-off voltage V term Information required for state of charge (SOC) calculation.

[0070] The communication unit 303 is used to realize the communication between the electricity meter and the host, and feed back the electricity meter sampling and calculation results to the host.

[0071] The power management unit 306 mainly provides working power, voltage reference, working clock, etc. for each functional unit of the fuel meter, so that the fuel meter can operate normally.

[0072] It can be understood that the battery fuel meter of this embodiment samples the battery state of charge determination method provided by the above-mentioned embodiments, so that the calculated smoothed remaining capacity value of the battery and the loaded voltage of the battery maintain a one-to-one correspondence, thereby ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge directly jumps to zero at the end of battery discharge.

[0073] An embodiment of the present application further provides a battery system, which includes a battery fuel meter as provided in the above embodiments, and further includes energy storage cells and a battery management system (BMS), which is the above-mentioned power management unit 306.

[0074] It can be understood that since the battery system adopts the battery fuel meter provided by the above embodiments, the smoothed remaining capacity value of the battery calculated by the battery system and the loaded voltage of the battery maintain a one-to-one correspondence, thereby ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge directly jumps to zero at the end of battery discharge.

[0075] The present application also provides an electronic device comprising the battery fuel meter provided in the aforementioned embodiments; or the electronic device comprising the battery system provided in the aforementioned embodiments. The electronic device may be a smart terminal (such as a mobile phone or tablet), a smart wearable device (such as a smart bracelet or smart watch), a laptop computer, or other electronic product.

[0076] It can be understood that since the electronic device adopts the battery fuel meter provided by the above embodiments, the smoothed remaining capacity value of the battery calculated by the battery system and the loaded voltage of the battery maintain a one-to-one correspondence, thereby ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge directly jumps to zero at the end of battery discharge.

[0077] An embodiment of the present application further provides a computer-readable storage medium storing a computer program. When the computer program is run on a processor, the method for determining the battery state of charge provided by the above embodiments is executed.

[0078] The above embodiments can be implemented in whole or in part via software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions. When loaded or executed on a computer, the computer program instructions fully or partially perform the processes or functions described in the embodiments of this application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible by a computer or a data storage device such as a server or data center that includes a collection of one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, tape), optical media (e.g., DVD), or semiconductor media. The semiconductor media can be a solid-state drive (SSD).

[0079] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of this application.

[0080] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0081] In the several embodiments provided in the embodiments of the present application, it should be understood that the disclosed systems, electricity meters and methods can be implemented in other ways. For example, the electricity meter embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0082] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, and may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment as needed.

[0083] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0084] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a memory (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0085] The above description is merely a specific implementation of the embodiments of the present application, but the scope of protection of the embodiments of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the embodiments of the present application should be included in the scope of protection of the embodiments of the present application. Therefore, the scope of protection of the embodiments of the present application should be based on the scope of protection of the claims.

Claims

1. A method for determining a battery state of charge, characterized in that: The method comprises: After determining that the battery has entered a terminal discharge state, obtaining discharge parameter information of the battery at a current moment and an equivalent circuit model of the battery, the discharge parameter information of the battery at a current moment including: a current loaded voltage value, a current discharge temperature value, and a current discharge current value; determining a first depth of discharge of the battery at a current moment according to the equivalent circuit model of the battery and the current loaded voltage value, the current discharge temperature value, and the current discharge current value; Obtaining the cutoff voltage of the battery, using the current discharge temperature value as the discharge temperature value corresponding to when the battery reaches the cutoff voltage, and using the current discharge current value as the discharge current value corresponding to when the battery reaches the cutoff voltage; determining, based on an equivalent circuit model of the battery, a second depth of discharge corresponding to when the battery reaches the cutoff voltage according to the cutoff voltage and the discharge temperature value and discharge current value corresponding to when the cutoff voltage is reached; wherein the equivalent circuit model is expressed as: V term =OCV(DOD term )+I now *R(DOD term , T now ), where V term Indicates the battery's cut-off voltage, DOD term Indicates the second depth of discharge when the battery reaches the cut-off voltage, OCV (DOD term ) represents the open circuit voltage when the battery reaches the cut-off voltage, I now Indicates the current discharge current value of the battery at the current moment, T now Indicates the current discharge temperature value of the battery, R(DOD term , T now ) indicates that the battery is at the second depth of discharge value DOD now , and the current discharge temperature value T now Internal resistance value when determining a predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge, and determining a predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtaining a smoothed remaining capacity value of the battery at a current moment, and determining a unit discharge capacity of the battery per unit time based on the smoothed remaining capacity value at a current moment and the predicted remaining discharge time; determining a smoothed remaining capacity value of the battery at a next moment according to the smoothed remaining capacity value of the battery at a current moment and the unit discharge capacity; The state of charge of the battery is determined according to the smoothed remaining capacity value of the battery at the next moment and the full charge capacity value of the battery.

2. The method for determining the battery state of charge according to claim 1, wherein: Determining that the battery enters a terminal discharge state includes: During the battery discharge process, determining the remaining capacity of the battery, and when it is determined that the remaining capacity of the battery is less than or equal to a preset remaining capacity, determining that the battery enters a terminal discharge state; Alternatively, during the battery discharge process, the loaded voltage value of the battery is determined, and when it is determined that the loaded voltage value of the battery is less than or equal to a preset voltage value, it is determined that the battery enters a terminal discharge state.

3. The method for determining the battery state of charge according to claim 1 or 2, wherein: The determining the predicted discharge capacity of the battery according to the first depth of discharge and the second depth of discharge includes: Obtaining the maximum chemical capacity of the battery; The predicted discharge capacity of the battery when the battery reaches the cut-off voltage from a current moment is determined according to the maximum chemical capacity of the battery, the first discharge depth, and the second discharge depth.

4. The method for determining the battery state of charge according to claim 1 or 2, wherein: The obtaining of the smoothed remaining capacity value of the battery at the current moment includes: Determine the remaining capacity value corresponding to when the battery enters the terminal discharge state as the initial smoothed remaining capacity value; After the battery enters the terminal discharge state, the smoothed residual capacity value of the battery at the current moment is determined to be the smoothed residual capacity value at the previous moment minus the discharged power of the battery from the previous moment to the current moment.

5. A battery fuel gauge, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that when the processor executes the program, the steps of the method for determining the battery state of charge as described in any one of claims 1 to 4 are implemented.

6. A battery system, characterized in that: Comprising the battery fuel gauge as claimed in claim 5.

7. An electronic device, characterized in that: The electronic device comprises the battery fuel meter as claimed in claim 5; or the electronic device comprises the battery system as claimed in claim 6.

8. A computer-readable storage medium, characterized in that The computer program is stored therein, and when the computer program is run on a processor, the method for determining the battery state of charge according to any one of claims 1 to 4 is executed.

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