Calibration method for nearly full electric quantity of terminal equipment, chip and terminal

Abstract

The invention discloses a terminal device near full charge electric quantity calibration method, a chip and a terminal, the calibration method aims at the problem of inaccurate electric quantity of a consumer electronic terminal in a near full charge stage in the prior art, and two error directions of'small / large electric quantity calculation 'are judged in real time in a constant voltage stage through a preset electric quantity percentage-temperature-current relation table; weighted pull-up is adopted for'low electric quantity ', a time speed-limiting increment algorithm is adopted for'high electric quantity', calibration can be completed in a nearly full-charge stage without complete charging and discharging circulation, UI curve naked-eye non-inductive switching is achieved, and user experience is improved. Meanwhile, the algorithm complexity is low, and the method is suitable for being implemented in mobile phone PMIC or SoC firmware.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery management of consumer electronic terminals, and in particular to a method for online calibration of battery state of charge (SOC) when the battery power is close to 100% and a terminal device. BACKGROUND

[0002] The accuracy of battery power display is always a highly concerned issue for end users, especially for mobile phone users. Affected by Coulomb counting error, temperature drift and battery aging, the power gauge often shows "full charge too early" or "full charge too late" at the end of charging, making it difficult for users to accurately estimate the remaining available time. At the moment of charging cutoff, the terminal power may jump from less than 100% to 100%, and this jump phenomenon makes users perceive that the power is abnormal. In addition, if the terminal device starts discharging before the battery is truly fully charged, it may suddenly shut down without any warning, causing much inconvenience in daily use.

[0003] Smartphones, tablets and other terminal devices generally use lithium batteries for power supply. Such batteries basically follow a charging curve of constant current (CC) first and then constant voltage (CV) charging. According to the charging characteristics of lithium batteries, at the constant voltage stage, the charging current gradually decreases until it drops to the charging cutoff current Iterm, and the battery terminal voltage VBAT remains constant. At the same temperature, the current capacity of the battery and the current charging current show an approximately linear relationship, so the charging current at 99% power, the charging current at 98% power and the charging current at 97% power can be obtained by back calculation from the cutoff current, and a SOC-IBAT correspondence table can be established.

[0004] Based on the above SOC-IBAT relationship, the prior art has proposed corresponding calibration schemes. For example, the invention patent with publication number CN120446775A discloses a method for calibrating the SOC of a vehicle power battery, which includes the following steps: performing battery characteristic experiments at different temperatures; establishing a correspondence table of battery model parameters at different temperatures and SOC; establishing a current recursion formula at the constant voltage stage by deduction; performing current simulation at the constant voltage stage according to the current recursion formula and CV stage charging data, and establishing a temperature-current-SOC relationship table, which records the SOC calibration points when the current at the constant voltage stage drops to a specific value at different temperatures; writing the table into the battery management system (BMS), and calibrating the SOC in real time according to the current drop value at the constant voltage stage (paragraphs

[0048] -

[0052] of the specification). However, the above power battery SOC calibration scheme has the following disadvantages: 1. Based on Thevenin model and genetic algorithm parameter identification to derive current recursive formula, large amount of calculation, 10kB level RAM and BMS computing power are needed, which is difficult to be directly transplanted to mobile phone PMIC with RAM < 512B and CPU load < 1%; therefore, this method is for large-capacity battery pack, which needs complex battery model and BMS level computing power, and is difficult to be directly applied to resource-limited consumer terminals.

[0005] 2. Its trigger calibration condition is (see description

[0048] -

[0052] ): when various unexpected factors or human termination of charging in advance, the temperature-current-SOC calibration mechanism is triggered, the real SOC is calculated by interpolation according to the temperature and current at the last moment before the end, and the SOC calibration is triggered; in addition, if the charging is normal and the current reaches the cutoff current, the charging is automatically ended (the end of charging is usually determined by the current of the constant voltage stage, usually a value is given, when the current drops to this value, it is assumed that the battery is fully charged, and the charging is ended), the full charge calibration is triggered, and the SOC calibration is 100%. Based on the above calibration scheme, in the case of more power, the calibration will make the power jump down (instantaneous small jump) from high position, and in the case of less power, the calibration will make the power jump up (instantaneous large jump) from low position; that is, there is an unreasonable small jump of charging power, for example, the calibrated power of the battery jumps from 100% to 95% after being fully charged, which will cause trouble to the user. Therefore, this scheme is a power calibration at the moment of stopping charging, which lacks a UI smooth transition mechanism and will make the user perceive the power jump, and cannot be directly applied to resource-limited consumer terminals.

[0006] Therefore, there is an urgent need for a lightweight, online, and smooth near-full power calibration scheme. SUMMARY

[0007] In the following, a brief summary of embodiments of the present application is given in order to provide a basic understanding of some aspects of the present application. It should be understood that the following summary is not an exhaustive overview of the present application. It is not intended to identify key or important parts of the present application nor to delineate the scope of the present application. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

[0008] The present application proposes a terminal device near-full power calibration method, which distinguishes between "less power calculation" and "more power calculation" two error directions, respectively uses weighted lifting algorithm and time limiting algorithm, continuously calibrates at the end of the whole charging, and synchronously displays 100% at the physical full power point, and the UI display is smooth without jump.

[0009] According to a first aspect of the present application, a terminal device near-full power calibration method is provided, the terminal device is a consumer electronic terminal powered by a lithium battery, and the method comprises: S10, preset stage: at least two different temperatures, the lithium battery constant current-constant voltage charging test, generate and store the percentage of the relationship table, the relationship table at least includes: 100% SOC corresponding to the charging cutoff current Iterm; S20, real-time judgment stage: when the terminal device is in the charging state and the battery level meter output value BATT_SOC≥SOC_THD or the current charging current IBAT_NOW<IBAT_THD, enter the near full calibration window; SOC_THD is the first percentage of the relationship table, IBAT_THD is the first current of the relationship table; S30, error direction determination stage: Satisfy the preset condition of less power, then enter the "power calculation less" branch; Satisfy the preset condition of more power, then enter the "power calculation more" branch; S40, calibration calculation stage: In the "power calculation less" branch, execute the weighted lifting algorithm: S411, record the current sampling value IBAT_E of the moment when entering the "power calculation less" calibration window; S412, read the current charging current IBAT_NOW in real time in each power calculation period; S413, according to the "percentage of power-temperature-current" relationship table, the current battery temperature is indexed, and the percentage of power IBAT_SOC corresponding to the current charging current IBAT_NOW is found; S414, calculate the weight weight: weight=(IBAT_NOW–Iterm) / (IBAT_E–Iterm), 0≤weight≤1; Iterm is the charging cutoff current; In order to prevent weight from exceeding the interval, if IBAT_NOW≥IBAT_E, weight=0; if IBAT_NOW≤Iterm, weight=1.

[0010] S415, calculate the calibration power CALI_SOC: CALI_SOC=BATT_SOC×weight+IBAT_SOC×(1–weight); BATT_SOC is the battery level meter output value; S416, output the calibration power CALI_SOC as the final percentage of power in this period, and drive the user interface to update smoothly; S417, repeat S412-S416 until IBAT NOW≤Iterm and CALI_SOC reaches 100%, end calibration; In the branch of "SOC calculation more", execute time limit speed algorithm: S421, take the SOC gauge reading BATT_SOC_E when entering the "SOC calculation more" calibration window as the reference value, determine the first target SOC percentage, SOC_NEXT=BATT_SOC_E+1%; SOC_NEXT is the next integer SOC percentage to be reached; S422, according to the temperature-current-SOC relationship table at the current temperature, obtain the theoretical charging current IBAT_TABLE corresponding to the SOC percentage SOC=BATT_SOC_E; S423, calculate the theoretical time Time_need required to push the SOC percentage SOC from the reference value BATT_SOC_E to the target SOC percentage SOC_NEXT: Time_need=(SOC_NEXT–BATT_SOC_E)×FCC / IBAT_TABLE; Where FCC is the full charging capacity of the battery, in mAh; S424, in each SOC calculation period Δt, accumulate the accumulated actual time to obtain acc_time: acc_time=acc_time+Δt; the unit of Δt is s; S425, calculate the calibration SOC CALI_SOC in real time: CALI_SOC=BATT_SOC_E+(SOC_NEXT–BATT_SOC_E)×acc_time / Time_need; S426, when CALI_SOC≥SOC_NEXT and SOC_NEXT<100%, let SOC_NEXT increase by 1%, and clear acc_time, return to step S23; S427, repeat steps S423-S426 until the physical charging current IBAT decreases to the cutoff current Iterm and the calibration SOC CALI_SOC reaches 100%, end calibration; S50, display synchronization stage: take the calibration SOC CALI_SOC as the final output of the SOC gauge, and drive the terminal user interface to synchronously update the display SOC in a smooth form; S60, termination stage: when the charging current IBAT≤Iterm and the calibration SOC CALI_SOC=100%, end the current near-full calibration process.

[0011] As an implementation solution, the low power preset condition is that the following conditions are met for N consecutive periods: IBAT NOW < IBAT THD and BATT SOC < SOC THD; or IBAT NOW < IBAT SOC THD and BATT SOC >= SOC THD; where IBAT THD is the first current of the relationship table, SOC THD is the first percentage of the relationship table, IBAT SOC THD is the corresponding charging current when SOC = BATT SOC in the relationship table, N is a natural number, N >= 2; and simultaneously satisfy VBAT NOW >= VBAT FULL (full charge voltage) for N consecutive periods; The high power preset condition is that the following conditions are met for N consecutive periods: IBAT NOW >= IBAT THD and BATT SOC >= SOC THD; or IBAT NOW > IBAT SOC THD and BATT SOC >= SOC THD and VBAT NOW >= VBAT FULL.

[0012] As an implementation solution, the step S415 further includes a state of charge error correction process: The cumulative error correction threshold SOC ADJ THD of the state of charge is dynamically set in a preset range (for example, in the range of 0%-5%) according to different charging temperatures, for example: When the temperature TBAT >= 25 degrees, let SOC ADJ THD = 3%; When 25 degrees > temperature TBAT >= 15 degrees, let SOC ADJ THD = 4%; When 15 degrees > temperature TBAT >= 0 degrees, let SOC ADJ THD = 5%; When BATT SOC > IBAT SOC + SOC ADJ THD, BATT SOC is corrected as: BATT SOC = IBAT SOC + SOC ADJ THD; When BATT SOC < IBAT SOC - SOC ADJ THD, BATT SOC is corrected as: BATT SOC = IBAT SOC - SOC ADJ THD.

[0013] The present scheme will have a power "jump" in the first fitting or power meter cumulative error correction, at which time the power and the last period of power will exist SOC_GAP. To overcome this problem, as a kind of implementation scheme, the S416 further includes the process of power smoothing the output of the calibrated power CALI_SOC: according to the current charging current IBAT_NOW, the SOC_GAP is evenly distributed to the future remaining to be charged power SOC_TO_CHG=FULL_SOC-BATT_SOC, and the specific calculation method is as follows: S416-1 calculates the to-be-charged capacity SOC_TO_CHG: SOC_TO_CHG=FULL_SOC-CALI_SOC; S416-2 calculates the remaining time TIME_TO_FULL TIME_TO_FULL=SOC_TO_CHG×FCC / IBAT_NOW; S416-3 calculates the step number STEPS: STEPS=TIME_TO_FULL / TSTEP; Wherein, STEPS is rounded up, and ≥1; TSTEP is the power calculation period, that is, the time interval of each update of SOC by the power meter or the calibration algorithm, in seconds (s); S416-4 calculates the compensation amount of each step: com_soc=SOC_GAP / STEPS; SOC_GAP is the difference between the calibrated power CALI_SOC calculated at the moment of this calibration and the power meter output in the last period; S416-5 period compensation: Update the calibrated power every power calculation period: CALI_SOC=CALI_SOC+com_soc; Until IBAT_NOW≤ITERM, and CALI_SOC=FULL_SOC or com_soc=0, stop compensation.

[0014] In order to make the "speed limit rhythm" automatically stretch with temperature and aging, both to ensure the smoothness of UI and not to slow down or report full in advance, as a kind of feasible scheme, the dynamic speed limit factor k(T, SOH) is introduced in the time speed limit increment algorithm Time_need, which satisfies: k(T, SOH)=1.8-0.02×(T-25)-0.01×SOH_loss; Then Time_need is corrected: Time_need=k(T, SOH)×(SOC_NEXT-BATT_SOC_E)×FCC / IBAT_TABLE; where T is the real-time battery temperature, SOH_loss is the battery capacity attenuation percentage, obtained by the coulomb counter cycle count or OTA calibration.

[0015] To further guarantee the non-inductive switching, the application also designs a transition zone (which can be designed by itself) such as [94.5%, 95.5%] or [94%, 95%]. The non-inductive switching scheme of the transition zone is applied between steps S30 and S40, that is, after the positive and negative error directions are determined in the error direction determination stage S30, before entering the calibration calculation stage S40, the SOC is first processed once in the transition zone for smoothing. Specifically, the non-inductive switching scheme of the transition zone includes: If 94.5%≤SOC≤95.5%, then according to CALI_SOC= ×CALI_weight+(1- )×CALI_speed, =(SOC–94.5%) / (95.5%–94.5%), update by 0.1% step, realize continuity (derivative continuity); continuity, that is, the curve of CALI_SOC changing with time is continuous and derivable; When SOC<94.5% or SOC>95.5%, directly enter the "more power calculation" or "less power calculation" branch.

[0016] wherein CALI_SOC is the final output to the UI calibration power percentage, after "transition zone" or "more / less power double path" smoothing, the real number used to drive the screen power bar, system notification bar. CALI_weight is the instantaneous calibration result of the "less power calculation" branch, under the "less power calculation" branch, the SOC value calculated according to the weight formula (weighted lifting), used to quickly approach 100%. CALI_speed is the instantaneous calibration result of the "more power calculation" branch, under the "more power calculation" branch, the SOC value calculated according to the time speed increment algorithm, used to slowly and uniformly approach 100%, to prevent early full report.

[0017] As a feasible scheme, the "temperature-current-power percentage" relationship table is stored in the non-volatile storage area of the power management chip of the terminal device in the form of a two-dimensional array, and is loaded into the RAM at each boot. The size of the two-dimensional array is ≤256 bytes, stored in the form of uint8_t table[T_idx][SOC_idx] As a feasible solution, in the branch of "multiple power calculation", if the acc_time exceeds the preset maximum speed limit time and still does not meet CALI_SOC=100%, the CALI_SOC is forced to be 100% and the calibration is ended. The preset maximum speed limit time can be set to 180s-300s, which is determined according to the terminal heat dissipation capability and user experience test.

[0018] As a feasible solution, the error direction determination stage further includes: The current charging current IBAT is subjected to multi-point sliding (for example, 8-point sliding) average and first-order IIR filtering, and then compared with the current threshold IBAT_THD, so as to reduce the misjudgment rate caused by sampling noise. For example, the first-order IIR coefficient =0.25, and the sliding window length N=3.

[0019] According to a second aspect of the present application, a near-full power calibration chip is provided, comprising: A memory for storing the power percentage-temperature-current relationship table in the near-full power calibration method; A temperature sensor interface for obtaining the real-time temperature of the battery; A current sampling interface for obtaining the real-time charging current of the battery; An operation unit for executing the calibration calculation steps in the terminal device near-full power calibration method; An output interface for outputting the calibrated power CALI_SOC to the terminal host or display driver; Wherein, the operation unit is started when the terminal is in the constant voltage stage and SOC≥SOC_THD, and stopped when IBAT≤Iterm and CALI_SOC=100%.

[0020] As a feasible solution, the operation unit is a dedicated hardware microcode circuit. Generally, the number of instructions of the hardware microcode circuit is ≤64, which is used to complete the weight calculation, time limit and smooth output, and the execution cycle is ≤1µs According to a third aspect of the present application, a terminal device is provided, comprising: A lithium ion battery; A near-full power calibration chip; An application processor for receiving the calibrated power CALI_SOC output by the near-full power calibration chip and driving the user interface to display smoothly; A display for updating the power percentage UISOC in real time.

[0021] As a feasible solution, the terminal device is any one of a smartphone, a tablet, a wearable device, or a Bluetooth headset.

[0022] The prior art triggers the electric quantity calibration at the moment of stopping charging and completes the SOC correction at one time, which is a sudden change calibration, lacks a transition mechanism, and the user interface can have a significant electric quantity jump, which can easily lead to the user mistakenly thinking that the system is malfunctioning. The technical problem to be solved by the present application is: based on the obtained electric quantity percentage-temperature-current corresponding relationship, the electric quantity SOC is calibrated in real time during the entire near full charging stage, so that: 1. When the physical current drops to Iterm, the voltage and the electric quantity are at the physical full charging point, and the UI displays the electric quantity reaching 100% synchronously; 2. The calibration process is smooth without jump, so as to improve the user experience of consumer terminals.

[0023] The present application realizes a terminal device near full charging electric quantity calibration scheme by the above-mentioned scheme, and has the following advantages: 1. The calibration can be completed in the near full charging stage (95%-100% interval) without complete charging and discharging cycles, and the UI curve is switched without feeling by naked eye through the transition zone (width≤1%), so as to improve the user experience; 2. The algorithm complexity is low by dividing into the “electric quantity calculation less” branch and the “electric quantity calculation more” branch according to the error direction, which is suitable for implementation in the mobile phone PMIC or SoC firmware; at the same time, it has good noise immunity, and under the condition of 12-bit ADC and =0.25IIR filtering, the identification accuracy is ≥99.7% and the misjudgment rate is <0.3%; 3. The temperature and aging compensation are performed by introducing a dynamic speed limiting factor k(T, SOH), so that the aging battery can also be smoothly returned to zero error within 2 minutes without “stuttering” phenomenon; 4. It is compatible with existing electric quantity meter chips and can be completed in the PMIC without additional hardware cost, and the power consumption increment is <1mW. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application can be better understood by referring to the description given below in conjunction with the accompanying drawings, in which the same or similar reference signs are used to represent the same or similar parts throughout all the drawings. The drawings, together with the following detailed description, are included in the specification and form a part of the specification, and are used to further illustrate the preferred embodiments of the present application and explain the principles and advantages of the present application. In the drawings: Figure 1 It is a charging curve schematic diagram of a lithium battery in the prior art; Figure 2 It is a calibration method schematic diagram of an embodiment of the present application; Figure 3 It is an effect schematic diagram of the “electric quantity calculation less” branch in an embodiment of the present application; Figure 4 It is an effect schematic diagram of the “electric quantity calculation more” branch of an embodiment of the present application. DETAILED DESCRIPTION

[0025] Embodiments of the present application will be described below with reference to the accompanying drawings. Elements and features of one drawing or embodiment described in the present application can be combined with elements and features shown in one or more other drawings or embodiments. It should be noted that the representation and description of components and processes that are irrelevant to the present application and known to those of ordinary skill in the art are omitted from the drawings and the description for the purpose of clarity.

[0026] The terms applied to the present application are explained as follows: IBAT (BATTery current): battery charging current; BATT_SOC (BATTery SOC): battery percentage calculated by the power calculation method; MSOC (Measured SOC): final battery percentage measured by the power meter; UISOC (UI SOC): battery percentage displayed on the phone screen; CCCV (Constant Current Constant Voltage): constant current constant voltage conversion point voltage; VBAT (Voltage of Battery): battery terminal voltage; Iterm (Termination current): charging cutoff current; FCC (Full Charge Capacity): full capacity.

[0027] Embodiment 1 The embodiment of the present application provides a terminal device near-full power calibration method, referring to Figure 2 , comprising the following steps: Step 1: Pre-set stage: Obtain the relationship between charging current and power at different temperatures [IBAT, SOC] as the power percentage (SOC) - temperature (TBAT) - current (IBAT) relationship table (hereinafter referred to as IBAT-SOC relationship table or relationship table). In this embodiment, the relationship table is as follows:

[0028] Step 2: Real-time judgment stage: When the terminal device is in a charging state and the power meter output value BATT_SOC≥95% or the current charging current IBAT_NOW<IBAT_THD, enter the near-full power calibration window. For example, under the condition of 25 degrees, when the battery percentage calculated by the power calculation method BATT_SOC is greater than 95%, but the charging current IBAT is greater than 650mA at this time, it can be judged that the current BATT_SOC is too large and needs to be calibrated. Similarly, BATT_SOC is less than 95%, but the charging current IBAT is less than 650mA at this time, it can be judged that the current BATT_SOC is too small and needs to be calibrated.

[0029] Step 3: Error direction determination stage: Calibration entry condition for "less charge calculation" branch: condition 1 and condition 2 are met Condition 1: one of the following conditions is met IBAT NOW < IBAT THD for several consecutive charge statistics periods (e.g. 4 periods) and BATT SOC < SOC THD.

[0030] IBAT THD is the first current for calibration of IBAT-SOC relationship table, and SOC THD is the first charge for calibration of IBAT-SOC relationship table, such as 700mA and 95% at 45 degrees in the above table; For example: when the actual charge is greater than batt_soc, IBAT < IBAT_95 at this time, but BATT_SOC < 95 IBAT NOW < IBAT SOC THD for several consecutive charge statistics periods (e.g. 4 periods) and BATT SOC ≥ SOC THD.

[0031] IBAT SOC THD is the current found according to BATT SOC in IBAT-SOC relationship table, and SOC THD is the first charge for calibration of IBAT-SOC relationship table, such as 700mA and 95% at 45 degrees in the above table.

[0032] Condition 2: VBAT NOW ≥ VBAT FULL for several consecutive charge statistics periods.

[0033] Calibration entry condition for "more charge calculation" branch: IBAT NOW ≥ IBAT THD and BATT SOC ≥ SOC THD for N consecutive periods.

[0034] Step 4: "less charge calculation" branch: the charge calculated by the charge meter is less than the actual charge Execute the weighted boost algorithm: When the actual charge is greater than BATT_SOC, IBAT < IBAT_95 at this time, but BATT_SOC < 95, IBAT is used as the entry condition to calculate the weight weight.

[0035] weight = (IBAT NOW - Iterm) / (IBAT E - Iterm); Wherein, weight is the weight, weight ∈ [0, 1], IBAT NOW is the current charging current; Iterm is the charging cutoff current in the battery specification book, IBAT E is the current sampling value when entering the calibration window for the first time, that is, the first current that triggers the prediction, that is, the threshold point of entering the prediction calibration; CALI_SOC = BATT_SOC * weight + IBAT_SOC * (1 - weight); BATT_SOC is the output value of the fuel gauge; Wherein, CALI_SOC is the calibrated electric quantity, IBAT_SOC is the electric quantity percentage obtained according to the "electric quantity percentage-temperature-current" relationship table, and BATT_SOC is the electric quantity percentage output by the current fuel gauge (FGU).

[0036] The embodiment of the present application further corrects the error of the fuel gauge: The cumulative error correction threshold SOC_ADJ_THD of the fuel gauge is set to different values according to different charging temperatures: When the temperature TBAT is greater than or equal to 25 degrees, SOC_ADJ_THD = 3%; When 25 degrees > temperature TBAT ≥ 15 degrees, SOC_ADJ_THD = 4%; When 15 degrees > temperature TBAT ≥ 0 degrees, SOC_ADJ_THD = 5%; When BATT_SOC > IBAT_SOC + SOC_ADJ_THD, BATT_SOC is corrected as: BATT_SOC = IBAT_SOC + SOC_ADJ_THD; When BATT_SOC < IBAT_SOC - SOC_ADJ_THD, BATT_SOC is corrected as: BATT_SOC = IBAT_SOC - SOC_ADJ_THD.

[0037] The present scheme may have a "jump" in the electric quantity when fitting for the first time or correcting the cumulative error of the fuel gauge, and at this time, the electric quantity and the electric quantity of the last period may have a SOC_GAP. In order to overcome this problem, step S416 further includes a smoothing process of the calibrated electric quantity: according to the current charging current IBAT_NOW, the SOC_GAP is evenly distributed to the future remaining charging quantity SOC_TO_CHG = FULL_SOC - BATT_SOC, and the specific calculation method is as follows: Calculate how much time TIME_TO_FULL is needed to charge the full charging quantity SOC_TO_CHG with the current charging current IBAT_NOW; According to the current electric quantity calculation interval TSTEP, calculate how many periods are needed to be full STEPS = TIME_TO_FULL / TSTEP; Divide the SOC_GAP into STEPS: com_soc = SOC_GAP / STEPS; Each electric quantity calculation period compensates the electric quantity of com_soc to ensure that the electric quantity is continuous and smooth without jumping.

[0038] The "low power calculation" branch applies the above weighted pull-up algorithm to improve the power counted by the power meter. The effect after the improvement is as follows: Figure 3 As shown in the figure, the horizontal axis is time and the vertical axis is the percentage of power; BATT_SOC is the percentage of power output by the fuel gauge (a 10% error is artificially introduced, which is smaller than the actual power); BATT_SOC_R is the percentage of power output by the fuel gauge, which has no error and is used for comparison; CALI_SOC is the percentage of power after calibration; MSOC is the final output percentage of power by the fuel gauge; IBAT is the real-time current of power; IBAT_SOC is the SOC corresponding to the current charging current.

[0039] Depend on Figure 3 As can be seen, after this solution artificially introduces a 10% error, the battery level begins calibration when the charging current I BAT is less than I BAT_E, gradually reducing the error from 10% until it reaches the cutoff current I term . This means that charging stops at 100% and the battery level display becomes smooth. Without the calibration solution, BATT_SOC still has a 10% error when charging to I term , and is calibrated directly from 90% to 100% at full charge.

[0040] Step 5: In the "Power Calculation Excess" branch: The power meter's statistics are greater than the actual power. BATT_SOC reaches the calibration condition first. BATT_SOC cannot calibrate the power level with IBAT as the reference point, but it can limit the power increase by time.

[0041] Under the "Energy Calculation Multiple" branch, execute the time limit increment algorithm: 1. Using the battery gauge reading BATT_SOC_E when entering the "Battery Calculation" calibration window as the reference value, determine the first target battery percentage: SOC_NEXT = BATT_SOC_E + 1%. SOC_NEXT is the next target battery percentage to be reached (usually an integer). 2. According to the temperature-current-SOC relationship table at the current temperature, obtain the corresponding theoretical charging current IBAT_TABLE when the battery percentage SOC = BATT_SOC_E; 3. Calculate the theoretical time Time_need required to push the battery percentage SOC from the baseline value BATT_SOC_E to the target battery percentage SOC_NEXT: Time_need=(SOC_NEXT–BATT_SOC_E)×FCC / IBAT_TABLE; Where FCC is the fully charged capacity of the battery, in mAh; 4. In each power calculation cycle t, the accumulated actual time is accumulated to get acc_time: acc_time = acc_time + t; The unit of t is s; 5, calculate the power increase time: batt_cali_delta = (SOC_NEXT - BATT_SOC_E) x acc_time / Time_need; Calculate the output power: BATT_SOC_E + batt_cali_delta; Get the calibration power CALI_SOC: CALI_SOC = BATT_SOC_E + (SOC_NEXT - BATT_SOC_E) x acc_time / Time_need; 6, when CALI_SOC ≥ SOC_NEXT, and SOC_NEXT < 100%, let SOC_NEXT increase by 1%, and acc_time is cleared, return to step 3; 7, repeat steps 3-6 until the physical charging current IBAT drops to the cutoff current Iterm and the calibration power CALI_SOC reaches 100%, end calibration.

[0042] In this time-limited incremental algorithm, 1% of the power is divided into several small steps using the theoretical time Time_need. Every time an "electricity calculation period" is passed, acc_time is accumulated, and CALI_SOC is output in proportion. When CALI_SOC reaches SOC_NEXT, the target is increased by 1% and the timing is restarted. This cycle continues until the physical current reaches Iterm, which is exactly 100%.

[0043] The "electricity calculation multiple" branch reduces the electricity calculated by the above-mentioned time-limited incremental algorithm. The effect is shown in Figure 4 The figure shows that BATT_SOC is the percentage of the electricity calculated by the electricity meter (10% error is artificially introduced, less than the true electricity); CALI_SOC is the percentage of the calibrated electricity; MSOC is the final output percentage of the electricity meter; IBAT is the real-time current of the electricity.

[0044] As can be seen from Figure 4 , after artificially introducing a 10% error, when charging to BATT_SOC is greater than 95%, the electricity starts to calibrate and gradually decreases from the error of 10%. If there is no calibration scheme, the electricity will report 100% very early. After the electricity calibration, the electricity reporting is delayed, which is closer to the true electricity, and the electricity display is smooth.

[0045] ​To make the "speed limit rhythm" automatically stretch with temperature and aging, both to ensure the smooth UI and not to slow down or report full in advance, in this embodiment, the dynamic speed limit factor k(T, SOH) is introduced into the Time_need in the time speed limit increment algorithm, which satisfies: k(T, SOH) = 1.8 - 0.02 x (T - 25) - 0.01 x SOH_loss; Then Time_need is corrected as: Time_need = k(T, SOH) x (SOC_NEXT - BATT_SOC_E) x FCC / IBAT_TABLE; Where T is the real-time battery temperature, and SOH_loss is the battery capacity attenuation percentage, which is obtained by the cycle count of the power gauge or OTA calibration.

[0046] The dynamic speed limit factor k(T, SOH) has the following advantages: 1. Temperature compensation: Low temperature, high internal resistance, and fast current drop in the constant voltage stage → k becomes small (shorten each 1% time), avoid the power "card" at 97% not moving. High temperature, small internal resistance, and slow current drop → k becomes large (lengthen each 1% time), prevent the UI from reaching 100% too fast and the actual battery from being full.

[0047] 2. Aging compensation: After the battery decays, the capacity becomes smaller, and the duration of the constant voltage stage is shortened → k is linearly amplified with SOH_loss, and "physical full power" and "UI 100%" can be reached at the same time. Avoid the phenomenon that the existing technology's aging battery "after 600 cycles, the phone reports full at 95%".

[0048] 3. Zero increase in resources: The formula of k has only 2 multiplications and 2 additions, which can be completed in the existing MCU without additional RAM or power consumption Step 6: Display synchronization stage: take the calibrated power CALI_SOC as the final output of the power gauge, and drive the terminal user interface to update the display power in a smooth form; Step 7: Termination stage: when the charging current IBAT≤Iterm, and the calibrated power CALI_SOC=100%, end this near-full power calibration process.

[0049] As a specific application scenario, perform near-full power calibration on a 4500mAh battery: Preset stage: perform 0.7C constant current charging to 4.45V on a 4500mAh battery at 25℃, 10℃, and 45℃, respectively, and then constant voltage to 0.05C cutoff, record the constant voltage stage current and SOC correspondence, generate 3 groups of two-dimensional table and burn to the phone EEPROM.

[0050] Real-time judgment stage: when the SOC reported by the power meter is 96% and the system is in the constant voltage stage, enter the calibration window.

[0051] Error direction determination: if IBAT = 400mA < 650mA corresponding to 95% in the table, enter the "power calculation less" branch, calculate CALI_SOC according to the corresponding formula, and update the UI with a smoothness of 0.5% / s within 30s.

[0052] If IBAT = 700mA ≥ 650mA and SOC = 96%, enter the "power calculation more" branch, use the time-limited speed algorithm to linearly increase the UI power from 96% to 100% within 180s.

[0053] Termination stage: when IBAT drops to 225mA (0.05C, C is the rated capacity of the battery) and CALI_SOC = 100%, the system prompts "full", and the calibration process ends.

[0054] The application discloses a terminal device near-full power calibration method, comprising: presetting a temperature-current-SOC relationship table; entering a calibration window when the power meter output is greater than or equal to 95%; distinguishing two error directions of "power calculation less" and "power calculation more", and respectively adopting a weighted lifting or time-limited speed algorithm to calculate a calibration power CALI_SOC; outputting the CALI_SOC to a user interface to be displayed in a smooth form, and ending when the current drops to a cutoff value and the CALI_SOC is 100%. The method significantly improves the terminal device charging end power display accuracy and user experience without increasing hardware costs In the above description of the embodiments of the application, the features described and / or shown for one implementation can be used in one or more other implementations in the same or similar manner, in combination with features in other implementations, or in place of features in other implementations.

[0055] It should be emphasized that the term "comprises / comprising" when used in this text refers to the presence of a feature, element, step or component, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0056] In the above embodiments and examples, numerically composed reference signs are used to represent various steps and / or units. Those skilled in the art should understand that these reference signs are only for the convenience of description and drawing, and do not represent the order or any other limitation.

[0057] In addition, the method of the application is not limited to being performed in the time sequence described in the specification, but can also be performed in other time sequences, in parallel or independently. Therefore, the execution sequence of the method described in the specification does not limit the technical scope of the application.

[0058] While the application has been disclosed by reference to specific embodiments thereof, it will be understood that the foregoing description is illustrative only and not restrictive. Various modifications, improvements, and / or equivalents thereof will become apparent to those skilled in the art. Accordingly, the scope of the application should be determined not with reference to the above description but with reference to the appended claims.

Claims

1. A method for calibrating the nearly full power of a terminal device, characterized in that: The terminal device is a consumer electronic terminal powered by a lithium battery, and the method includes: S10, presetting stage: performing a constant current-constant voltage charging test on the lithium battery, generating and storing a power percentage-temperature-current relationship table, wherein the relationship table at least includes a charging cut-off current Iterm corresponding to 100% SOC; S20, real-time judgment stage: when the terminal device is in a charging state and the power meter output value BATT_SOC ≥ SOC_THD, or the current charging current IBAT_NOW < IBAT_THD, enter the nearly full charge calibration window; SOC_THD is the first power percentage in the relationship table, and IBAT_THD is the first current in the relationship table; S30, error direction determination stage: If the preset condition of low power is met, the system will enter the "low power calculation" branch; If the preset condition of more power is met, the "more power calculation" branch will be entered; S40, calibration calculation stage: In the "Balanced Power Calculation" branch, weight the power gauge output value BATT_SOC to obtain the calibrated power CALI_SOC. In the "Energy Calculation Multiple" branch, adjust the fuel gauge output value BATT_SOC based on the time-limited incremental algorithm to obtain the calibrated energy value CALI_SOC. S50, display synchronization stage: using the calibration power CALI_SOC as the final output of the power meter, and driving the terminal user interface to synchronously update the displayed power in a smooth manner; S60, termination stage: When the charging current IBAT ≤ Iterm and the calibration capacity CALI_SOC = 100%, the nearly full-charge calibration process ends.

2. The method for calibrating the nearly full charge of a terminal device according to claim 1, wherein: Under the "Balanced Power Calculation" branch, the power gauge output value BATT_SOC is weighted and increased, specifically including: S411, record the current sampling value IBAT_E at the moment of entering the "low power calculation" calibration window; S412, reading the current charging current IBAT_NOW in real time during each power calculation cycle; S413. According to the "battery percentage-temperature-current" relationship table, find the battery percentage IBAT_SOC of the current charging current IBAT_NOW at the same temperature; S414. Calculate weight: weight=(IBAT_NOW–Iterm) / (IBAT_E–Iterm), 0≤weight≤1; Iterm is the charge cutoff current; S415, calculate calibration power CALI_SOC: CALI_SOC = BATT_SOC × weight + IBAT_SOC × (1 – weight); BATT_SOC is the output value of the fuel gauge; S416: Output the calibration power CALI_SOC as the final power percentage of the cycle, and drive the user interface to update smoothly; S417. Repeat S412-S416 until the current charging current IBAT_NOW ≤ Iterm and the calibration power CALI_SOC reaches 100%, then the calibration ends. Under the "Energy Calculation Multiple" branch, adjust the fuel gauge output value BATT_SOC based on a time-limited incremental algorithm, specifically: S421. Using the battery gauge reading BATT_SOC_E when entering the "Battery Calculation" calibration window as the reference value, determine the first target battery percentage: SOC_NEXT = BATT_SOC_E + 1%; SOC_NEXT is the next integer battery percentage to be reached. S422. Obtain the theoretical charging current IBAT_TABLE corresponding to the battery percentage SOC = BATT_SOC_E according to the temperature-current-SOC relationship table at the current temperature. S423. Calculate the theoretical time Time_need required to push the battery percentage SOC from the reference value BATT_SOC_E to the target battery percentage SOC_NEXT: Time_need=(SOC_NEXT–BATT_SOC_E)×FCC / IBAT_TABLE; Where FCC is the fully charged capacity of the battery, in mAh; S424. In each power calculation cycle Δt, the accumulated actual time is accumulated to obtain acc_time: acc_time=acc_time+Δt; the unit of Δt is s; S425, real-time calculation of calibration power CALI_SOC: CALI_SOC=BATT_SOC_E+(SOC_NEXT–BATT_SOC_E)×acc_time / Time_need; S426: When CALI_SOC≥SOC_NEXT and SOC_NEXT<100%, SOC_NEXT is incremented by 1%, acc_time is cleared, and the process returns to step S23; S427. Repeat steps S423-S426 until the physical charging current IBAT drops to the cut-off current Iterm and the calibration charge CALI_SOC reaches 100%, and then the calibration is terminated.

3. The method for calibrating the nearly full charge of a terminal device according to claim 1, wherein: In S30, the preset condition for low power is: N consecutive cycles satisfying: IBAT_NOW < IBAT_THD and BATT_SOC < SOC_THD; or IBAT_NOW<IBAT_SOC_THD and BATT_SOC≥SOC_THD; Where IBAT_THD is the first current in the relationship table, SOC_THD is the first power percentage in the relationship table; IBAT_SOC_THD is the charging current corresponding to SOC=BATT_SOC in the relationship table; N is a natural number, N≥2; And at the same time, the current charging VBAT_NOW ≥ VBAT_FULL within N consecutive cycles; VBAT_FULL is the fully charged voltage; The preset condition for excess power is: N consecutive cycles meet the following conditions: IBAT_NOW ≥ IBAT_THD and BATT_SOC ≥ SOC_THD; or IBAT_NOW>IBAT_SOC_THD and BATT_SOC ≥ SOC_THD and VBAT_NOW ≥ VBAT_FULL.

4. The method for calibrating the nearly full charge of a terminal device according to claim 2, wherein: The step S415 also includes a fuel gauge error correction process: Dynamically set the fuel gauge cumulative error correction threshold SOC_ADJ_THD within a preset range according to different charging temperatures; When BATT_SOC>IBAT_SOC+SOC_ADJ_THD, correct BATT_SOC to: BATT_SOC=IBAT_SOC+SOC_ADJ_THD; When BATT_SOC<IBAT_SOC-SOC_ADJ_THD, BATT_SOC is corrected to: BATT_SOC=IBAT_SOC-SOC_ADJ_THD.

5. The method for calibrating the nearly full charge of a terminal device according to claim 1, wherein: Time_need in the time speed limit increment algorithm introduces a dynamic speed limit factor k(T, SOH): k(T, SOH)=1.8–0.02×(T–25)–0.01×SOH_loss; Where T is the real-time battery temperature, SOH_loss is the battery capacity attenuation percentage, which is obtained by the fuel gauge cycle count or OTA calibration; Then Time_need is corrected to: Time_need = k(T, SOH) × (SOC_NEXT – BATT_SOC_E) × FCC / IBAT_TABLE.

6. The method for calibrating the nearly full charge of a terminal device according to claim 2, wherein: The step S416 also includes a process of smoothing the output calibration power CALI_SOC, and the specific calculation method is as follows: S416-1 calculates the capacity to be charged SOC_TO_CHG: SOC_TO_CHG=FULL_SOC-CALI_SOC; S416-2 calculates the remaining time TIME_TO_FULL: TIME_TO_FULL=SOC_TO_CHG×FCC / IBAT_NOW; S416-3 Calculate the number of steps: STEPS=TIME_TO_FULL / TSTEP; Among them, STEPS is a guaranteed integer and ≥1; TSTEP is the power calculation period, in seconds; S416-4 calculates the compensation amount for each step: com_soc = SOC_GAP / STEPS; SOC_GAP is the difference between the calibration power CALI_SOC calculated at the moment of this calibration and the power meter output of the previous cycle; S416-5 cycle compensation: Update the calibration power in each power calculation cycle: CALI_SOC=CALI_SOC+com_soc; Compensation stops when IBAT_NOW≤ITERM and CALI_SOC=FULL_SOC or com_soc=0.

7. A nearly fully charged power calibration chip, characterized in that: include: Memory for the table of power percentage-temperature-current relationship; Temperature sensor interface, used to obtain real-time battery temperature; Current sampling interface, used to obtain real-time battery charging current; A computing unit, configured to execute the calibration calculation step in the method for calibrating the nearly full charge of a terminal device according to any one of claims 1 to 6; Output interface, used to output the calibration power CALI_SOC to the terminal main control or display driver; The operation unit is started when the terminal is in the constant voltage stage and SOC≥SOC_THD, and is stopped when IBAT≤Iterm and CALI_SOC=100%.

8. The nearly full-charge calibration chip according to claim 7, wherein: The arithmetic unit is a dedicated hardware microcode circuit.

9. A terminal device, characterized in that: include: lithium-ion batteries; The nearly full-charge calibration chip according to claim 7 or 8; An application processor is configured to receive the calibration power CALI_SOC output by the nearly full-power power calibration chip and drive a smooth display of the user interface; Display, used to update the battery percentage UISOC in real time.

10. The terminal device according to claim 9, characterized in that The terminal device is any one of a smart phone, a tablet, a wearable device or a Bluetooth headset.

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