Methods for determining battery state of charge, fuel gauges, battery systems and electronic equipment.

Abstract

This application relates to the field of battery management technology, and more particularly to a method for determining the state of charge (SOC) of a battery, a fuel gauge, a battery system, and an electronic device. The method for determining the SOC includes: after the battery enters the final discharge state, continuously predicting the smoothed remaining capacity value at the next moment based on the current smoothed remaining capacity value. Since the prediction period is generally short, the temperature and load of the battery during discharge change very little; therefore, the influence of the battery's temperature and load on its internal resistance can be ignored. Furthermore, calculating the smoothed remaining capacity value of the battery in two consecutive calculations cancels out the influence of the battery's internal resistance on the calculated smoothed remaining capacity value, ensuring a one-to-one correspondence between the calculated smoothed remaining capacity value and the battery's load voltage. This guarantees the accuracy of the monitored SOC and avoids the situation where the battery's SOC jumps directly to zero at the end of the discharge process.

Description

Technical Field

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

[0002] Battery systems are widely used in technologies 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 using a fuel gauge. This means that the fuel gauge tracks and monitors the battery's state of charge (SOC) so that users can understand the remaining chemical capacity of the battery in a timely manner.

[0003] In related technologies, during battery discharge, it is assumed that when the battery reaches the cutoff voltage, its actual remaining capacity will also reach zero. Then, at the start of discharge, the battery's internal resistance is calculated using an internal resistance model. Based on this calculated internal resistance, the remaining capacity under different load voltages is simulated and calculated using the same model. The battery's state of charge (SOC) is then updated based on this simulated SOC. However, in real-world scenarios, the battery's internal resistance changes due to variations in operating temperature and load. Therefore, when calculating the SOC using existing simulation methods, the remaining capacity typically does not reach zero simultaneously when the load voltage reaches the cutoff voltage. This causes the SOC to jump directly to zero at the end of discharge, affecting the accuracy of the monitored SOC. Summary of the Invention

[0004] This application provides a method for determining the state of charge of a battery, a fuel gauge, a battery system, and an electronic device to solve the technical problem in the related art where the state of charge of a battery jumps directly 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, this application provides a method for determining the state of charge of a battery, the method comprising:

[0006] After determining that the battery has entered the final discharge state, the discharge parameter information of the battery at the current moment is obtained, and the first depth of discharge of the battery is determined 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: the current load voltage value, the current discharge temperature value, and the current discharge current value;

[0007] Obtain the cutoff voltage of the battery, and determine the second depth of discharge 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.

[0008] The predicted discharge capacity of the battery is determined based on the first discharge depth and the second discharge depth, and the 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 in a unit time is determined based on the smoothed remaining capacity value at the current moment and the predicted remaining discharge time.

[0009] Based on the smoothed remaining capacity value of the battery at the current moment and the unit discharge capacity, determine the smoothed remaining capacity value of the battery at the next moment;

[0010] The state of charge of the battery is determined based on the smoothed remaining capacity value of the battery at the next moment and the full charge capacity value of the battery.

[0011] In one possible design, determining that the battery has entered the final discharge state includes:

[0012] During the battery discharge process, the remaining capacity of the battery is determined. When the remaining capacity of the battery is determined to be less than or equal to a preset remaining capacity, the battery is determined to enter the end discharge state.

[0013] Alternatively, during the battery discharge process, the load voltage value of the battery is determined, and when the load voltage value of the battery is determined to be less than or equal to a preset voltage value, the battery is determined to enter the end discharge state.

[0014] In one possible design, determining the first depth of discharge of the battery based on the current discharge parameter information of the battery includes:

[0015] Obtain the equivalent circuit model of the battery;

[0016] Based on the equivalent circuit model of the battery, and according to the current load voltage, current discharge temperature, and current discharge current of the battery, the first depth of discharge of the battery at the current moment is determined.

[0017] In one possible design, obtaining the cutoff voltage of the battery and determining the second depth of discharge corresponding to when the battery reaches the cutoff voltage based on the current discharge temperature, current discharge current, and the cutoff voltage includes:

[0018] The current discharge temperature value is taken as the discharge temperature value corresponding to when the battery reaches the cutoff voltage, and the current discharge current value is taken as the discharge current value corresponding to when the battery reaches the cutoff voltage.

[0019] Based on the equivalent circuit model of the battery, and according to the cutoff voltage and the corresponding discharge temperature and discharge current values ​​when the cutoff voltage is reached, the second depth of discharge corresponding to the battery reaching the cutoff voltage is determined.

[0020] In one possible design, determining the predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge includes:

[0021] Obtain the maximum chemical capacity of the battery;

[0022] Based on the battery's maximum chemical capacity, first depth of discharge, and second depth of discharge, determine the predicted discharge capacity of the battery when it reaches the cutoff voltage at the current moment.

[0023] In one possible design, obtaining the smoothed remaining capacity value of the battery at the current moment includes:

[0024] The remaining capacity value corresponding to when the battery enters the end discharge state is determined to be the initial smoothed remaining capacity value;

[0025] After the battery enters the final discharge state, the smoothed remaining capacity of the battery at the current moment is determined to be the smoothed remaining capacity value of the previous moment minus the discharge amount of the battery from the previous moment to the current moment.

[0026] Secondly, this application also provides a battery fuel gauge, which includes a memory and a processor. The memory stores a computer program, and the processor executes the program to implement the steps of the method for determining the state of charge of a battery as described in any of the preceding claims.

[0027] Thirdly, this application also provides a battery system including a battery fuel meter as provided in any of the above claims.

[0028] Fourthly, this application also provides an electronic device that includes a battery fuel meter as provided in any of the preceding claims; or the electronic device includes a battery system as described above.

[0029] Fifthly, this application also provides a computer-readable storage medium storing a computer program that, when run on a processor, executes the method for determining the state of charge of a battery as described in any of the preceding claims.

[0030] The method for determining the state of charge (SOC) of a battery, as described in the first aspect above, firstly, after determining that the battery has entered the final discharge state, obtains the discharge parameter information of the battery at the current moment, and determines the 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 the second depth of discharge corresponding to the battery reaching the cutoff voltage based on the current discharge temperature value, the current discharge current value, and the cutoff voltage; then, determines the predicted discharge capacity of the battery based on the first and second depths of discharge, and determines the predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtains the 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 of the battery at the current moment and the predicted remaining discharge time; determines the 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; finally, determines the SOC of the battery 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 final 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. Therefore, the influence of the battery temperature value and load size on the internal resistance can be ignored. Furthermore, the smoothed remaining capacity value of the battery is calculated in two consecutive steps, which cancels out the influence of the battery internal resistance on the calculated smoothed remaining capacity value. This ensures that the calculated smoothed remaining capacity value of the battery and the battery's load voltage maintain a one-to-one correspondence, guaranteeing the accuracy of the monitored battery state of charge and avoiding the situation where the battery's state of charge jumps directly to zero at the end of the discharge.

[0031] The beneficial effects provided by the other aspects and the various possible designs of the other aspects can be found in the beneficial effects of the first aspect and the various possible implementations of the first aspect, and will not be repeated here. Attached Figure Description

[0032] Figure 1 A schematic flowchart illustrating the method for determining the state of charge of a battery provided in an embodiment of this application;

[0033] Figure 2 A schematic diagram illustrating the relationship between depth of discharge and load voltage provided in the embodiments of this application;

[0034] Figure 3 This is a schematic diagram of the battery power meter structure provided in an embodiment of this application. Detailed Implementation

[0035] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] The terms “center,” “longitudinal,” “lateral,” “up,” “down,” “left,” “right,” “front,” and “rear,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] The terms "connected" and "connected" should be interpreted broadly. For example, in circuit structures, "connected" or "connected" can refer not only to physical connections but also to electrical or signal connections. This could be a direct connection (physical connection) or an indirect connection via at least one intermediate component, as long as the circuit is connected. It could also refer to the internal connection between two components. Similarly, a signal connection can refer to a connection via a circuit or a medium, such as radio waves. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.

[0038] The following is a description of the terms used in this application:

[0039] State of charge (SOC) is used to reflect the remaining capacity of a battery, which is the percentage of battery charge.

[0040] The internal resistance of a battery refers to the resistance encountered when current flows through the battery during operation. The internal resistance of a battery changes continuously over time during charging and discharging because the composition of the active material, the concentration of the electrolyte, and the temperature are constantly changing.

[0041] Open circuit voltage (OCV) is the difference between the potential of the positive electrode and the potential of the negative electrode when the battery is open-circuited (i.e., when no current flows through the two electrodes).

[0042] Depth of discharge (DOD) refers to the percentage of energy that can be extracted from a battery relative to its rated capacity.

[0043] The remaining capacity (RM) of a battery refers to the maximum amount of electricity that the battery can discharge in its current state until it reaches the discharge termination voltage. The discharge termination voltage, also known as the cutoff voltage or cut-off voltage, is the lowest operating voltage at which the battery should no longer discharge during operation.

[0044] Full Charge Capacity (FCC) refers to the maximum amount of electricity a battery can release after being fully charged.

[0045] In related technologies, during battery discharge, it is assumed that when the battery reaches the cutoff voltage, its actual remaining capacity will also reach zero. Then, at the start of discharge, the battery's internal resistance is calculated using a battery internal resistance model. Based on this calculated internal resistance, the remaining capacity under different load voltages is simulated using the same model. The battery's state of charge (SOC) is then updated based on this simulated SOC. Specifically, at initial power-on, the battery's full charge capacity and remaining capacity are sampled as a baseline. During battery operation, the internal resistance is calculated using the battery internal resistance model, and the remaining capacity is simulated using current integration. The SOC is then determined based on this simulated SOC. However, in real-world operating scenarios, the battery's internal resistance changes with variations in operating temperature and load. The internal resistance calculated using a battery internal resistance model remains constant. Therefore, there's a discrepancy between the internal resistance calculated using the model and the actual internal resistance during battery operation. This causes the remaining capacity of the battery to not reach zero synchronously when the load voltage reaches the cutoff voltage, as calculated using existing simulation methods. Consequently, the battery's state of charge (SOC) jumps directly to zero at the end of the discharge process, affecting the accuracy of the monitored SOC.

[0046] To overcome the shortcomings of the aforementioned related technologies, this application provides a method for determining the state of charge (SOC) of a battery. First, after determining that the battery has entered the final discharge state, the method acquires the battery's current discharge parameter information and determines the first depth of discharge based on this information. Then, it acquires the battery's cutoff voltage and determines the second depth of discharge corresponding to the cutoff voltage based on the battery's current discharge temperature, current discharge current, and cutoff voltage. Next, it determines the battery's predicted discharge capacity based on the first and second discharge depths and determines the predicted remaining discharge time based on the current discharge current and predicted discharge capacity. Finally, it acquires the 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 and predicted remaining discharge time. Then, it determines the smoothed remaining capacity value of the battery at the next moment based on the smoothed remaining capacity value and unit discharge capacity. Finally, it determines the battery's SOC based on the smoothed remaining capacity value and full charge capacity of the battery at the next moment. In this way, after the battery enters the final 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. Therefore, the influence of the battery temperature value and load size on the internal resistance can be ignored. Furthermore, the smoothed remaining capacity value of the battery is calculated in two consecutive steps, which cancels out the influence of the battery internal resistance on the calculated smoothed remaining capacity value. This ensures that the calculated smoothed remaining capacity value of the battery and the battery's load voltage maintain a one-to-one correspondence, guaranteeing the accuracy of the monitored battery state of charge and avoiding the situation where the battery's state of charge jumps directly to zero at the end of the discharge.

[0047] Figure 1 For a flowchart illustrating the method for determining the state of charge of a battery as provided in this application embodiment, please refer to [link / reference]. Figure 1 As shown, the method for determining the state of charge of a battery provided in this embodiment includes:

[0048] S101. After determining that the battery has entered the end discharge state, obtain the discharge parameter information of the battery at the current moment, and determine the first discharge depth 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: the current load voltage value, the current discharge temperature value, and the current discharge current value.

[0049] In one embodiment of this application, the method for determining the state of charge of the battery further includes: during the battery discharge process, acquiring the remaining capacity or load voltage value of the battery in real time, and determining whether the battery has entered the end discharge state based on the remaining capacity or load voltage value.

[0050] In one embodiment of this application, determining that the battery has entered the end-of-discharge state specifically includes: determining the remaining capacity of the battery during the battery discharge process, and determining that the battery has entered the end-of-discharge state when the remaining capacity of the battery is less than or equal to a preset remaining capacity.

[0051] For example, in one application scenario, the preset remaining capacity of the battery can be set to 100mAh. Then, during the battery discharge process, when it is determined that the remaining capacity of the battery is less than or equal to 100mAh, the battery is determined to enter the end discharge state.

[0052] In one embodiment of this application, determining that the battery has entered the end-of-discharge state specifically includes: during the battery discharge process, determining the battery's load voltage value, and when the battery's load voltage value is determined to be less than or equal to a preset voltage value, determining that the battery has entered the end-of-discharge state.

[0053] For example, in one application scenario, the preset voltage of the battery can be set to 3.2V and the cutoff voltage of the battery can be set to 3.1V. Then, during the battery discharge process, when it is determined that the battery load voltage is less than 3.2V, the battery is determined to enter the end discharge state.

[0054] In one embodiment of this application, determining the first depth of discharge of the battery based on the discharge parameter information of the battery at the current moment includes: obtaining the 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, the current load voltage value, the current discharge temperature value, and the current discharge current value.

[0055] Specifically, since there is a one-to-one correspondence between the battery's open-circuit voltage (OCV) and its depth of discharge (DOD), based on the battery system's internal resistance table, for a given discharge current I, the theoretical load voltage at a given depth of discharge (DOD) and discharge temperature can be expressed as follows using the zero-order battery model:

[0056] V load = OCV(DOD) + I * R(DOD, T) (1)

[0057] In the above formula (1), V load The values ​​represent the battery's load voltage, DOD represents the battery's depth of discharge, OCV(DOD) represents the open-circuit voltage when the battery's depth of discharge is DOD, I represents the battery's discharge current, T represents the battery's operating temperature, and R(DOD, T) represents the internal resistance when the battery's depth of discharge is DOD and the battery's operating temperature is T.

[0058] Based on the equivalent circuit model of the battery shown in formula (1) above, when the battery enters the final discharge state, the following relationship expression can be obtained for the current moment:

[0059] V now =OCV(DOD now )+I now *R(DOD now , T now (2)

[0060] In the above expression, V load DOD represents the current load voltage value of the battery at the current moment. now OCV (DOD) represents the battery's first depth of discharge at the current moment. now This indicates the battery's first depth of discharge (DOD) at the current moment. now Open circuit voltage at time, I now T represents the current discharge current value of the battery at the current moment. now R(DOD) represents the current discharge temperature of the battery. now , T now This indicates the battery's first depth of discharge (DOD). now And the current discharge temperature value T now The internal resistance value at that time.

[0061] It is understandable 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 these can be acquired through the battery management system or the corresponding sampling circuit, and then the first depth of discharge (DOD) value at the current moment can be calculated. now .

[0062] S102. Obtain the battery's cutoff voltage, and determine the second depth of discharge corresponding to when the battery reaches the cutoff voltage based on the battery's current discharge temperature, current discharge current, and cutoff voltage.

[0063] It is understandable that the time from when the battery enters the final discharge state until it reaches the cutoff voltage is generally short, and the battery's operating temperature and discharge current change little during this period. Therefore, the battery's current operating temperature T can be used. now and discharge current value I now These are the operating temperature and discharge current values ​​corresponding to when the battery reaches its cutoff voltage.

[0064] In one embodiment of this application, based on the above-described inventive concept and according to the equivalent circuit model of the battery shown in formula (1), when the battery enters the final discharge state, the corresponding relationship between the battery's cutoff voltage and the second depth of discharge can be obtained, which can be specifically expressed as:

[0065] V term =OCV(DOD term )+I now *R(DOD term , T now (3)

[0066] In the above expression (3), V term Indicates the battery's cutoff voltage, DOD term OCV (DOD) represents the second depth of discharge when the battery reaches the cutoff voltage. term I represents the open-circuit voltage when the battery reaches its cutoff voltage. now T represents the current discharge current value of the battery at the current moment. now R(DOD) represents the current discharge temperature of the battery. term , T now This indicates the battery's second depth of discharge (DOD) value. term And the current discharge temperature value T now The internal resistance value at that time.

[0067] It can be seen that, according to the above method, after acquiring the cutoff voltage V term Current load voltage value V load Current discharge temperature value T now and the current discharge current value I now Based on this, the first discharge depth value (DOD) at the current moment is then obtained. now The second depth of discharge (DOD) when the battery reaches the cutoff voltage term .

[0068] S103. Determine the predicted discharge capacity of the battery based on the first discharge depth and the second discharge depth, and determine the predicted remaining discharge time of the battery based on the current discharge current value and the predicted discharge capacity; obtain the smoothed remaining capacity value of the battery at the current moment, and determine 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.

[0069] In one embodiment of this application, the predicted discharge capacity Q of the battery can be obtained by combining the first and second discharge depths of the battery with the battery's maximum chemical capacity Qmax. cap .

[0070] Specifically, determining the predicted discharge capacity of the battery based on the first depth of discharge and the second depth of discharge includes: obtaining the maximum chemical capacity of the battery; and determining the predicted discharge capacity of the battery when it reaches the cutoff voltage at the current moment based on the maximum chemical capacity of the battery, the first depth of discharge, and the second depth of discharge.

[0071] Specifically, the predicted discharge capacity of the battery can be obtained according to the following formula:

[0072] Q cap = Qmax * (DOD term - DOD now (4)

[0073] In the above formula (4), Qmax represents the maximum chemical capacity of the battery, Q cap DOD represents the predicted discharge capacity of the battery when it reaches the cutoff voltage at the current moment. term Indicates the second depth of discharge value, DOD now This represents the first depth of discharge value.

[0074] It can be seen that when calculating the first and second depths of discharge of the battery using the above method, the second depth of discharge calculated using the above method is relatively accurate because the changes in discharge current and discharge temperature at the end of the discharge are very small.

[0075] Furthermore, when using the above formula (4) to calculate the predicted discharge capacity based on two discharge depths, the internal resistance of the battery can theoretically be offset, which 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.

[0076] Then, based on the current discharge current and the predicted discharge capacity, the predicted remaining discharge time of the battery is determined. Specifically, the predicted remaining discharge time of the battery can be determined using the following formula:

[0077] S t = Q cap / I now (5)

[0078] In the above formula (5), S t Q represents the predicted remaining discharge duration. cap I represents the predicted discharge capacity of the battery when it reaches the cutoff voltage at the current moment. now This indicates the current discharge current value of the battery, which can be used to represent the battery's discharge rate.

[0079] 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.

[0080] Understandably, in order for the battery to reach the cutoff voltage V term At that time, the battery's state of charge (SOC) reaches zero simultaneously, which means the current smoothing remaining capacity (SmoothRM) needs to be calculated based on the predicted remaining discharge time (S). t If the battery is discharged completely within a certain time, then the discharge capacity per unit time can be determined. For example, if one second is taken as the unit of time, the discharge capacity of the battery in one second can be expressed as:

[0081] C = SmoothRM * 3600 / S t (6)

[0082] In the above formula (6), C represents the battery's discharge capacity in one second, SmoothRM represents the battery's current smoothed remaining capacity, and S t This indicates the predicted remaining discharge duration.

[0083] S104. Determine the smoothed remaining capacity value of the battery at the next moment based on the smoothed remaining capacity value and unit discharge capacity of the battery at the current moment.

[0084] The interval between the current moment and the next moment can be set according to the actual scenario. For scenarios with high requirements for the accuracy of the State of Charge (SOC), the interval between the current moment and the next moment can be set to a shorter interval, such as one second. For scenarios with general requirements for the accuracy of the SOC, the interval between the current moment and the next moment can be set to a longer interval, such as two or three seconds.

[0085] In one embodiment of this application, the remaining capacity value corresponding to when the battery enters the final 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 by current integration methods is relatively accurate when the battery just enters the final discharge state, it can be used as a reference value. After the battery enters the final 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 discharge amount released by the battery from the previous moment to the current moment.

[0086] It is understandable that after the battery enters the final discharge state, the smoothed remaining capacity value of the battery at any time can be obtained by subtracting the discharge capacity of the battery at adjacent times from the initial smoothed remaining capacity value.

[0087] Understandably, since the prediction period is generally short, the temperature and load of the battery during discharge change very little. Therefore, the influence of the battery temperature and load on the internal resistance can be ignored, and the smoothed remaining capacity value calculated in this way is more accurate.

[0088] In this embodiment, the smoothed remaining capacity value is relative to the actual remaining capacity value of the battery; that is, it 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 given time can be calculated using the above method, and for any intermediate time, the smoothed remaining capacity value at any given time can be obtained by smoothing the remaining capacity values ​​of the battery at two adjacent times.

[0089] Figure 2 A schematic diagram illustrating the relationship between depth of discharge and load voltage provided in embodiments of this application is shown below. Figure 2 As shown, the horizontal axis represents the depth of discharge. Figure 2 The value is represented by DOD on the left and right axes, with the vertical axis representing the load voltage. Figure 2 The symbol V represents the open-circuit voltage (OCV) curve of the battery. The solid line below the dashed line represents the load voltage V after applying a discharge current I. load The curve, V term It is the specified discharge cutoff voltage value of the battery system, when the load voltage V load Reaching this cutoff voltage value V term At this time, the State of Charge (SOC) needs to be 0, and the corresponding first depth of discharge is represented by the Depth of Discharge (DOD). now Indicates. V load This represents the battery's current load voltage; the corresponding second depth of discharge is denoted by DOD. term express.

[0090] S105. Determine the state of charge of the battery based on the smoothed remaining capacity value and the full charge capacity value of the battery at the next moment.

[0091] The battery's full-charge capacity can be obtained from battery parameters or the battery management system. After obtaining the smoothed remaining capacity and the battery's full-charge capacity at the next moment, the battery's state of charge can be determined based on the following formula:

[0092] SmoothSOC = SmoothRM / SmoothFCC (7)

[0093] Wherein, SmoothRM is the smoothed remaining capacity of the battery; SmoothFCC is the full charge capacity of the battery; and SmoothSOC is the state of charge of the battery.

[0094] The state of charge (SOC) can be displayed as a percentage, a numerical value, or a diagram, allowing users to intuitively and clearly understand the current SOC of the battery.

[0095] According to the method provided in this embodiment, after the battery enters the end 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. Therefore, the influence of the battery temperature value and load size on the internal resistance can be ignored. Furthermore, the smoothed remaining capacity value of the battery is calculated in two adjacent calculations, which cancels out the influence of the battery internal resistance on the calculated smoothed remaining capacity value. This ensures that the calculated smoothed remaining capacity value of the battery and the battery's load voltage maintain a one-to-one correspondence, guaranteeing the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge jumps directly to zero at the end of the battery discharge.

[0096] Figure 3 For a schematic diagram of the battery fuel gauge structure provided in the embodiments of this application, please refer to [link / reference]. Figure 3 As shown in the illustration, this application also provides a battery fuel gauge, which includes a memory 302 and a processor 301. The memory 302 stores a computer program that can run on the processor. When the processor 301 executes the program, it implements the steps of the battery state of charge determination method provided in any of the above embodiments. The battery state of charge determination method includes: after determining that the battery has entered the end of its discharge state, acquiring the battery's current discharge parameter information, and determining the battery's first depth of discharge based on the battery's current discharge parameter information; the battery's current discharge parameter information includes: the current load voltage value, the current discharge temperature value, and the current discharge current value; acquiring the battery's cutoff voltage, and determining the battery's current discharge depth ... current discharge parameter information; the battery's current discharge parameter information includes: the current load voltage value, the current discharge temperature value, and the current discharge current value; and the battery's current discharge depth. The system uses the pre-discharge temperature, current discharge current, and cutoff voltage to determine the second depth of discharge when the battery reaches the cutoff voltage. Based on the first and second depths of discharge, it determines the predicted discharge capacity of the battery, and based on the current discharge current and predicted discharge capacity, it determines the predicted remaining discharge time. It obtains the smoothed remaining capacity value of the battery at the current moment, and based on the smoothed remaining capacity value and predicted remaining discharge time, it determines the unit discharge capacity of the battery per unit time. Based on the smoothed remaining capacity value and unit discharge capacity of the battery at the current moment, it determines the smoothed remaining capacity value of the battery at the next moment. Based on the smoothed remaining capacity value of the battery at the next moment and the battery's full charge capacity, it determines the state of charge of the battery.

[0097] Optionally, the processor can be a central processing unit (CPU).

[0098] Please continue reading Figure 3As shown, the battery power meter also includes a voltage and temperature sampling conversion unit 304, a current and coulomb integration sampling conversion unit 305, a power management unit 306, and a communication unit 303.

[0099] The voltage and temperature sampling conversion unit 304 is used to sample the battery's discharge temperature and load voltage. Specifically, the voltage and temperature sampling conversion unit 304 includes a voltage sampling circuit 341, a temperature sampling circuit 342, a channel switcher 343, and a communication analog-to-digital converter 344. The voltage sampling circuit 341 samples the load voltage, the temperature sampling circuit 342 samples the discharge temperature, and the communication analog-to-digital converter 344 performs analog-to-digital conversion on the sampled analog load voltage and analog discharge temperature to obtain digital load voltage and discharge temperature values. The channel switcher 343 controls the switching of sampling channels to switch between voltage sampling and temperature sampling.

[0100] 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.

[0101] It should be noted that batteries typically have charging and discharging processes. During the charging process, the coulomb-integral analog-to-digital converter (ADC) samples the input battery charging current, integrates it over time to accumulate the charging capacity, and outputs the load current value, which is the charging current value. During the discharging process, the ADC samples the input battery discharging current, integrates it over time to accumulate the discharging capacity, and outputs the load current value (i.e., the discharging current value).

[0102] Among them, memory 302 is used to store the battery internal resistance meter R(DOD, T), open circuit voltmeter OCV(DOD), and cutoff voltage V. term Information required for calculating the State of Charge (SOC).

[0103] The communication unit 303 is used to realize the communication between the fuel meter and the host, and to feed back the sampling and calculation results of the fuel meter to the host.

[0104] The power management unit 306 mainly provides working power, voltage reference, and working clock for each functional unit of the fuel meter so that the fuel meter can work normally.

[0105] It is understood that, because the battery power meter in this embodiment samples the battery state of charge determination method provided in the above embodiments, the calculated smooth remaining capacity value of the battery and the battery load voltage maintain a one-to-one correspondence, ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery state of charge jumps directly to zero at the end of the battery discharge.

[0106] This application also provides a battery system, which includes a battery fuel meter as provided in the above embodiments, and the battery system also includes energy storage cells and a battery management system (BMS), which is the power management unit 306 described above.

[0107] It is understandable that, because the battery system uses the battery fuel gauges provided in the above embodiments, the smooth remaining capacity value of the battery calculated by the battery system and the battery load voltage maintain a one-to-one correspondence, ensuring the accuracy of the monitored state of charge of the battery, and avoiding the situation where the state of charge of the battery jumps directly to zero at the end of the battery discharge.

[0108] This application also provides an electronic device, which includes the battery fuel meter provided in the above embodiments; or the electronic device includes the battery system provided in the above embodiments. The electronic device can be a smart terminal (such as a mobile phone or tablet computer), a smart wearable device (such as a smart bracelet or smartwatch), a laptop computer, or other electronic products.

[0109] It is understandable that, because the electronic device uses the battery fuel gauges provided in the above embodiments, the smooth remaining capacity value of the battery calculated by the battery system and the battery's load voltage maintain a one-to-one correspondence, ensuring the accuracy of the monitored battery state of charge and avoiding the situation where the battery's state of charge jumps directly to zero at the end of the battery discharge.

[0110] This application also provides a computer-readable storage medium storing a computer program that, when run on a processor, executes the battery state-of-charge determination method provided in the above embodiments.

[0111] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. 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, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive (SSD).

[0112] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the embodiments of this application.

[0113] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0114] In the several embodiments provided in this application, it should be understood that the disclosed system, fuel meter, and method can be implemented in other ways. For example, the fuel meter embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0115] 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; 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 this embodiment, depending on actual needs.

[0116] In addition, the functional units in the various embodiments of this application 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.

[0117] If the aforementioned function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application embodiment, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a memory (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0118] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A method for determining the state of charge of a battery, characterized in that, The method includes: After determining that the battery has entered the final discharge state, the discharge parameter information of the battery at the current moment and the equivalent circuit model of the battery are obtained. The discharge parameter information of the battery at the current moment includes: the current load voltage value, the current discharge temperature value, and the current discharge current value. Based on the equivalent circuit model of the battery, the first depth of discharge of the battery at the current moment is determined according to the current load voltage value, the current discharge temperature value, and the current discharge current value. The cutoff voltage of the battery is obtained, and the current discharge temperature value is taken as the discharge temperature value corresponding to when the battery reaches the cutoff voltage. The current discharge current value is taken as the discharge current value corresponding to when the battery reaches the cutoff voltage. Based on the equivalent circuit model of the battery, and according to the cutoff voltage and the discharge temperature and discharge current values ​​corresponding to when the cutoff voltage is reached, the second depth of discharge corresponding to when the battery reaches the cutoff voltage is determined. The equivalent circuit model is represented as: V term =OCV(DOD term )+I now *R(DOD term , T now ), where V term Indicates the battery's cutoff voltage, DOD term OCV (DOD) represents the second depth of discharge when the battery reaches the cutoff voltage. term I represents the open-circuit voltage when the battery reaches its cutoff voltage. now T represents the current discharge current value of the battery at the current moment. now R(DOD) represents the current discharge temperature of the battery. term , T now This indicates the battery's second depth of discharge (DOD) value. term And the current discharge temperature value T now The internal resistance value at that time; The predicted discharge capacity of the battery is determined based on the first discharge depth and the second discharge depth, and the 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 in a unit time is determined based on the smoothed remaining capacity value at the current moment and the predicted remaining discharge time. Based on the smoothed remaining capacity value of the battery at the current moment and the unit discharge capacity, determine the smoothed remaining capacity value of the battery at the next moment; The state of charge of the battery is determined based on 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 state of charge of a battery according to claim 1, characterized in that, The process of determining that the battery has entered the final discharge state includes: During the battery discharge process, the remaining capacity of the battery is determined. When the remaining capacity of the battery is determined to be less than or equal to a preset remaining capacity, the battery is determined to enter the end discharge state. Alternatively, during the battery discharge process, the load voltage value of the battery is determined, and when the load voltage value of the battery is determined to be less than or equal to a preset voltage value, the battery is determined to enter the end discharge state.

3. The method for determining the state of charge of a battery according to claim 1 or 2, characterized in that, Determining the predicted discharge capacity of the battery based on the first discharge depth and the second discharge depth includes: Obtain the maximum chemical capacity of the battery; Based on the battery's maximum chemical capacity, first depth of discharge, and second depth of discharge, determine the predicted discharge capacity of the battery when it reaches the cutoff voltage at the current moment.

4. The method for determining the state of charge of a battery according to claim 1 or 2, characterized in that, The step of obtaining the smoothed remaining capacity value of the battery at the current moment includes: The remaining capacity value corresponding to when the battery enters the end discharge state is determined to be the initial smoothed remaining capacity value; After the battery enters the final discharge state, the smoothed remaining capacity of the battery at the current moment is determined to be the smoothed remaining capacity value of the previous moment minus the discharge amount of the battery from the previous moment to the current moment.

5. A battery fuel gauge, characterized in that, The device includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the program to implement the steps of the method for determining the state of charge of a battery as described in any one of claims 1 to 4.

6. A battery system, characterized in that, Includes the battery fuel gauge as described in claim 5.

7. An electronic device, characterized in that, The electronic device includes the battery fuel gauge as described in claim 5; or the electronic device includes the battery system as described in claim 6.

8. A computer-readable storage medium, characterized in that, It stores a computer program that, when run on a processor, executes the method for determining the state of charge of a battery as described in any one of claims 1 to 4.

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