Method, circuit and system for estimating remaining charging time for household energy storage

Abstract

The present invention relates to a charging remaining time estimation method, circuit module, system and method applied to household energy storage. The present invention provides an advance estimation value of each charging time for a segmented constant current charging system, and proportionally corrects the entire charging remaining time according to the stable charging current in the initial stage, thereby optimizing the problem of charging time variation caused by different currents in each charging.

Description

Technical Field

[0001] The invention relates to a method, circuit and system for estimating remaining charging time applied to household energy storage. Background Art

[0002] With the rapid development of electronic product technology, users have higher and higher requirements for the accessories of electronic products. For example, for the power battery in electric vehicles and the battery in mobile terminals, users need to know the time required for the battery to discharge once and the time required for charging once, especially the display of the remaining charging time. The accurate display of the remaining charging time can help users arrange their daily affairs reasonably.

[0003] At present, the patents CN201410232723.4 on the calculation method of the remaining charging time of the battery and the battery system have the following problems in the calculation of the remaining charging time estimation: Problem 1: During the charging process, the charging current is reduced due to factors such as faults, causing the estimated remaining charging time to fluctuate greatly; Problem 2: During the use of household energy storage cabinets, the battery capacity decay and the change of charging environment temperature affect the remaining battery charging time; Problem 3: The constant voltage charging increases the difficulty of BMS controlling the charging, and the current changes rapidly. The charging time estimation at this stage is difficult and has poor accuracy. The above three problems will affect the calculation accuracy of the remaining charging time, which will obviously cause a relatively poor user experience.

[0004] During the charging process of household energy storage cabinets, accurate estimation of the remaining charging time not only helps save user time and make users more satisfied, but also helps maximize the utilization rate of household energy storage cabinets.

[0005] At present, the industry's method for estimating the remaining charging time of household energy storage cabinets is to make a separate estimate based on the charging stage of the battery, or to estimate the remaining charging time based on the preset power, ignoring the problem of changes in charging time caused by reduced charging current due to factors such as battery aging, temperature changes, and charging failures.

[0006] The patent application number: 201610070711.5, the invention patent with the public name of "A method for estimating the remaining charging time of a battery", uses the charging time at different rates stored in history as a reference, stores the charging data for each time, and uses it as a reference for estimating the remaining time for the next charge. This method improves the charging time change caused by battery aging. However, it does not take into account that even in the constant current section of the charging process of household energy storage cabinets, there is a problem of charging time fluctuation caused by a decrease in charging current due to a fault.

[0007] The patent application number: 201610662092.9, the public name of the invention patent is "A method and device for calculating the remaining charging time of a household energy storage cabinet", which can accurately estimate the remaining charging time based on the current highest single cell voltage and historical data fitting. However, it does not take into account the factors that the current reduction caused by faults during charging cannot be approximately fitted with historical data.

[0008] The patent application number: 201611036262.9, the invention patent with the public name of "Method and device for determining the remaining charging time of a battery", uses the current power and the predetermined power of constant current to constant voltage charging to estimate the remaining time, which improves the estimation accuracy. However, it does not consider the impact of battery aging and ambient temperature on the maximum rechargeable capacity, which in turn affects the accuracy of charging time estimation. Summary of the invention

[0009] The technical problem to be solved by the present invention is generally to provide a method, circuit and system for estimating the remaining charging time for household energy storage.

[0010] To solve the above problems, the technical solution adopted by the present invention is:

[0011] A method for estimating the remaining charging time for household energy storage is provided, and a module of a charging and discharging control circuit of several household energy storage cabinets is provided. The module forms a charging and discharging control system and performs current execution signal flow.

[0012] The invention has reasonable design, low cost, durability, safety and reliability, simple operation, time-saving, labor-saving, money-saving, compact structure and convenient use.

[0013] The present invention provides an advance estimate of the charging time for each segment for a segmented constant current charging system, and proportionally corrects the remaining time of the entire charging according to the stable charging current in the initial stage, thereby optimizing the problem of charging time variation caused by different currents in each charging.

[0014] The present invention estimates the first constant current section of charging in a more refined manner and calculates the remaining charging time of this section by linear interpolation;

[0015] The present invention increases the adaptive adjustment of charging time caused by reducing the charging current during the charging process;

[0016] The present invention summarizes the charging process [C n ,T em ,T2],[C n ,T em ,Q2], adjust the charging time variation problem caused by battery attenuation or differential changes.

[0017] The present invention provides an advance estimate of the charging time for each segment for a segmented constant current charging system, and corrects the remaining time of the entire charging in proportion to the stable charging in the initial stage;

[0018] The present invention calculates the remaining charging time of the first constant current section by linear interpolation;

[0019] The present invention increases the adaptive adjustment of charging time caused by reducing the charging current during the charging process;

[0020] Induction during charging [C n ,T em ,T2],[C n ,T em ,Q2], adjust the charging time variation problem caused by battery attenuation or differential changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the main flow chart of the present invention;

[0022] Figure 2 The capacity rule learning process of the present invention;

[0023] Figure 3 It is the charging time estimation process of the terminal current reduction stage of the present invention;

[0024] Figure 4 The charging time adaptive adjustment process of the present invention;

[0025] Figure 5 This is the charging capacity confirmation process at each stage of the present invention.

[0026] Figure 6 It is a schematic diagram of the overall circuit of the charge and discharge control module of the present invention.

[0027] Figure 7 It is a circuit diagram of the power input protection module of the present invention.

[0028] Figure 8 It is a circuit diagram of the charging control module of the present invention.

[0029] Fig. 9 It is a circuit diagram of the pre-charge control module of the present invention.

[0030] Fig.10 It is a circuit diagram of the discharge control module of the present invention.

[0031] Fig.11 It is a circuit diagram of the current sampling module of the present invention. DETAILED DESCRIPTION

[0032] like Figure 1-11The present invention provides a system and method for estimating the remaining charging time for a household energy storage cabinet, which can more accurately estimate the remaining charging time, adaptively adjust the remaining charging time, and prevent the remaining charging time from jumping suddenly.

[0033] One aspect of the present invention provides a method for determining the remaining charging time of a household energy storage cabinet, which is implemented by the following technical solutions:

[0034] A method for estimating the remaining charging time of a household energy storage cabinet, the process is as follows:

[0035] S1, initializing the SOC-OCV parameter table of the battery used to form a [SOC, OCV] table;

[0036] S2, initializing charging data, forming a [T, SOC, C] table according to the charging rates C of constant current charging corresponding to different ambient temperatures T and different SOCs;

[0037] S3, calculate the total available capacity Q of the battery in S1 a =Q r ·SOH, where Q a is the total available capacity of the battery, Q r is the rated capacity of the battery, SOH is the battery aging life, that is, the current capacity remaining decay rate;

[0038] S4, according to the current cell voltage value, look up the [SOC, OCV] table to determine the current remaining power, recorded as SOC p ;

[0039] S5. According to the SOC of step S4 p , S2's [T, SOC, C] table, determine the battery's charging capacity Q at each constant current stage x , charging rate C x , x∈[s,n], s∈[1,n], n is the total number of charging segments in the [T,SOC,C] table, s is the number of remaining charging segments in [T,SOC,C];

[0040] S6. Calculate the remaining time T of the first stage of charging s ,

[0041] S7. Calculate the remaining theoretical charging time T for each constant current charging stage x Total theoretical charging time T d ; in,

[0042]

[0043] S8. Based on the actual charging rate C at the start of battery charging a , corrected theoretical charging time T d ';in, C s It is the theoretical charging rate in the first stage;

[0044] S9. When a fault causes the charging current to change, it will affect the remaining charging time. Therefore, the flow rate is set to ε, 0≤ε≤1, and the theoretical charging time T is corrected. d ″,

[0045] Among them, 0<ε, when ε=0, charging is finished, and the remaining charging time is T d "" = 0;

[0046] S10. According to the flow reduction rate ε, the charging time T is dynamically adjusted according to formula (4) d ″, to prevent the remaining charging time from changing suddenly;

[0047] S11. According to the charging current C at the end of the constant current stage n , battery cell temperature T em , query the battery's [C,T em ,T2] table, the remaining charging time T2 of the terminal down-current section is estimated by linear interpolation method;

[0048] S13. Theoretical charging time T according to step S9 d ″ and the remaining charging time T2 of step S11, the total remaining charging time is calculated as T d ″+T2;

[0049] S14. During each charging process, self-learning [C n ,T em ,T2],[C n ,T em ,Q2] forms a dynamic rule base to facilitate subsequent charging table lookup.

[0050] Further, a method for calculating the remaining capacity and charging time at the charging terminal;

[0051] In S14, according to the fuzzy algorithm, it is necessary to train rules and induction [C n ,T em ,T2],[C n ,T em ,Q2]; Among them, S14.1, performs the flow reduction stage judgment;

[0052] If yes, execute S14.2A. First, query the cell T before current reduction. em , constant current C n; Then, calculate the charging capacity by current integration and count the charging time; Secondly, when charging is completed and fully charged, store the calculated [C n ,T em ,T2],[C n ,T em ,Q2], when the charging is completed before the full charge, the calculated [C n ,T em ,T2],[C n ,T em ,Q2];

[0053] Otherwise, execute S14.2B; first, cumulatively calculate the charging capacity of each stage, and then, when the charging of the stage is completed, store the charging capacity of the corresponding stage; then return to S14.1;

[0054] In step S11, first, according to [C n , T em ], read the closest [C0, C1], [T em0 , T em1 ]; Then, linear interpolation method is used to obtain T2;

[0055] The purpose of the remaining charging time correction strategy is: 1. To prevent the charging time from increasing; 2. To prevent the remaining charging time from fluctuating; through step S9, the original unit time (1min) is set to be counted as α, and the current unit time is adjusted to α / ε, and the timer does not need to be reconfigured.

[0056] In step S5, the capacity of each stage is confirmed, wherein the capacity Q corresponding to the initial charging stage is S First, query the charging capacity table of each stage to obtain the corresponding capacity Q of each stage S ,Q2,…Q n ; Then, the remaining charging capacity is calculated at the beginning of charging, Q1 = (SOC-SOC s ) / (SOC s +1-SOC)*Q S .

[0057] like Figure 6 The charging and discharging control circuit of the household energy storage cabinet includes a power input protection circuit, a PCHG pre-charging control circuit, a PDCHG pre-discharging control circuit, a CHG charging control circuit, a DCHG discharging control circuit, a current sampling circuit, and a switch tube failure self-detection circuit.

[0058] like Figure 7 , a power input protection module, which includes capacitors C5, C6, a safety capacitor C162, a discharge tube D42, terminals J1, J3, and varistors RV1, RV2;

[0059] The power supply is provided by a battery pack, the positive electrode of the battery pack is connected to the BAT+ terminal J1, and the negative electrode of the battery pack is connected to the BAT- terminal J3 of this circuit; the positive terminal of the external load or charger is connected to the positive electrode of the battery pack through the positive terminal of the battery PACK, and the negative terminal of the external load or charger is connected to the PACK- terminal J3 of this circuit through the negative terminal of the battery PACK; the current flows from the negative electrode of the battery pack to the BAT- terminal J4;

[0060] A safety capacitor C162 is connected in parallel between the power terminals J1 and J3 to filter out surge noise signals on the power line; capacitors C5 and C6 are connected in series and connected in parallel with the voltage stabilizing diode D1 to the α end of BATPWR and terminal J3; the α end is connected to the β end through the varistor RV2, and the β end is connected to the power terminal J1 through the varistor RV1; the β end is connected to the PE end through the discharge tube D42; the α end is connected to the node A;

[0061] Varistors RV1 and RV2 provide current limiting protection, and discharge tube D42 provides input lightning protection; capacitors C5 and C6 are connected in series and then in parallel between power terminals J1 and J3 to filter out high-frequency noise on the power line; a voltage regulator diode D1 is connected in parallel between power terminals J1 and J3 to prevent input power spikes from damaging subsequent components; BAT-terminal J4 is connected in parallel to node A through series capacitors C1 and C2 and diode D65;

[0062] like Figure 8 , PCHG pre-charge control circuit, which includes N-channel MOS tube Q22, Q1 body diode resistors R74, R75, cement resistors R1-R4; cement resistors R1-R4 are connected in parallel to form a pre-charge current limiting resistor;

[0063] Pin 1 of MOS tube Q22 is connected to pin 1 of MOS tube Q1; resistor R75 is connected between pins 2 and 3 of MOS tube Q22, pin 3 is connected to pre-charge control signal PCHG through resistor R75; pin 2 is connected to node A through pre-charge current limiting resistor;

[0064] The gate of MOS tube Q22 is connected to the pre-charge control signal PCHG of the single-chip microcomputer MCU in series with the resistor R74. When pre-charging, the pre-charge control signal PCHG becomes high level to turn on MOS tube Q22, and is connected in series with the body diode of MOS tube Q1 to form a charging circuit; the charging current flows from the positive end of the charger through the positive end of the battery PACK to the positive electrode of the battery pack, and then the current flows from the negative electrode of the battery pack to the BAT-terminal J4, passes through the current sampling circuit and the pre-charge loop, returns to the PACK-terminal J3 of this circuit, and reaches the negative end of the charger through the negative end of the battery PACK. At the end of pre-charging, the pre-charge control signal becomes low level to turn off MOS tube Q22, so that the pre-charge loop is disconnected;

[0065] like Figure 8, PDCHG pre-discharge control circuit, which includes N-channel MOS tube Q1, body diode inside MOS tube Q22, resistors R5, R36; MOS tube Q1 pin 3 is connected to pin 2 through resistor R36;

[0066] The gate of MOS tube Q1 is connected to the resistor R5 in series with the microcontroller pre-discharge control signal PDCHG; when pre-discharging, the pre-discharge control signal PDCHG becomes high level to turn on MOS tube Q1, and is connected in series with the body diode of MOS tube Q22 to form a pre-discharge loop; the discharge current flows out from the positive electrode of the battery pack through the positive end of the battery PACK, passes through the charger or external load, and flows into the PACK-terminal J3 of this circuit from the negative end of the battery PACK, passes through the PDCHG pre-discharge control circuit and the current sampling circuit, and returns to the BAT-terminal J4 to reach the negative electrode of the battery pack. At the end of pre-discharge, the pre-discharge control signal becomes low level to turn off MOS tube Q1, so that the pre-discharge loop is disconnected;

[0067] like Fig. 9 , CHG charging control circuit, which includes a first group of parallel N-channel MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, Q18 and another group of parallel Q3, Q5, Q7, Q9, Q13, Q15, Q17, Q19 internal body diodes; the gates of MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, Q18 are connected in series with corresponding resistors and then connected to the single-chip microcomputer charging control signal CHG; when charging, the charging control signal becomes a high level to turn on the parallel MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, Q18, and the parallel Q3, The internal body diodes of Q5, Q7, Q9, Q13, Q15, Q17, and Q19 are connected in series to form a charging circuit; the charging current flows from the positive end of the charger through the positive end of the battery PACK into the positive electrode of the battery pack, and then the current flows from the negative electrode of the battery pack into the BAT-terminal J4, passes through the current sampling circuit and the CHG charging control circuit and returns to the PACK-terminal J3, and reaches the negative end of the charger through the negative end of the battery PACK; when charging is completed, the charging control signal becomes low level, and the parallel MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, and Q18 are turned off, so that the charging circuit is disconnected;

[0068] like Fig.10, DCHG discharge control circuit, which includes a group of parallel N-channel MOS tubes Q3, Q5, Q7, Q9, Q13, Q15, Q17, Q19 and another group of parallel MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, Q18 internal body diodes; MOS tubes Q3, Q5, Q7, Q9, Q13, Q15, Q17, The gate of Q19 is connected to the discharge control signal DCHG of the microcontroller after the resistor is connected in series. When discharging, the discharge control signal DCHG becomes high level to turn on the parallel MOS tubes Q3, Q5, Q7, Q9, Q13, Q15, Q17, Q19, and is connected in series with the internal body diodes of the parallel MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, Q18 to form a discharge circuit. The discharge current flows out from the positive electrode of the battery pack through the positive end of the battery PACK, and after passing through the charger or external load, it flows from the negative end of the battery PACK into the PACK-terminal J3 of this circuit, passes through the above-mentioned discharge circuit and current sampling circuit, and returns to the BAT-terminal J4, reaching the negative electrode of the battery pack. At the end of discharge, the discharge control signal becomes low level, turning off the parallel MOS tubes Q3, Q5, Q7, Q9, Q13, Q15, Q17, Q19, and disconnecting the discharge circuit.

[0069] like Fig.11 The current sampling circuit includes four parallel sampling resistors R39-R42 and a filter circuit consisting of resistors R37, R38, and capacitors C91, C90, and C11;

[0070] The switch tube failure self-check circuit includes two groups of parallel MOS tubes connected in series, and resistors R234, R235, and R242; the two groups of parallel MOS tubes include one group of parallel N-channel MOS tubes Q3, Q5, Q7, Q9, Q13, Q15, Q17, and Q19 and another group of parallel MOS tubes Q2, Q4, Q6, Q8, Q12, Q14, Q16, and Q18;

[0071] If one of the two parallel MOS tubes is short-circuited or open-circuited, the voltage at the connection point of R234 and R235 will change significantly. When the battery is in an idle state, the voltage change at this point can be detected in real time to detect whether the MOS tube is short-circuited or open-circuited.

[0072] Attached Figure 7-11 yes Figure 6 The terminals of the disassembly diagram have the same letters.

[0073] The present invention is fully described for a clearer disclosure, and the prior art is not listed one by one.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein with equivalents; it is obvious for those skilled in the art to combine multiple technical solutions of the present invention. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention. The technical contents not described in detail in the present invention are all known technologies.

Claims

1. A method for estimating the remaining charging time for household energy storage, characterized in that: Here are the steps: S1, initializing the SOC-OCV parameter table of the battery used to form a [SOC, OCV] table; S2, initializing charging data, forming a [T, SOC, C] table according to the charging rates C of constant current charging corresponding to different ambient temperatures T and different SOCs; S3, calculate the total available capacity Q of the battery in S1 a =Q r ·SOH, where Q a is the total available capacity of the battery, Q r is the rated capacity of the battery, SOH is the battery aging life, that is, the current capacity remaining decay rate; S4, according to the current cell voltage value, look up the [SOC, OCV] table to determine the current remaining power, recorded as SOC p ; S5. According to the SOC of step S4 p , S2's [T, SOC, C] table, determine the battery's charging capacity Q at each constant current stage x , charging rate C x , x∈[s,n], s∈[1,n], n is the total number of charging segments in the [T,SOC,C] table, and s is the number of remaining charging segments in [T,SOC,C]; S6. Calculate the remaining time T of the first stage of charging s , S7. Calculate the remaining theoretical charging time T for each constant current charging stage x Total theoretical charging time T d ; in, S8. Based on the actual charging rate C at the start of battery charging a , corrected theoretical charging time T d ';in, C s It is the theoretical charging rate in the first stage; S9. When a fault causes the charging current to change, it will affect the remaining charging time. Therefore, the flow rate is set to ε, 0≤ε≤1, and the theoretical charging time T is corrected. d ″, Among them, 0<ε, when ε=0, charging is finished, and the remaining charging time is T d "" = 0; S10. According to the flow reduction rate ε, the charging time T is dynamically adjusted according to formula (4) d ″, to prevent the remaining charging time from changing suddenly; S11. According to the charging current C at the end of the constant current stage n , battery cell temperature T em , query the battery's [C,T em ,T2] table, the remaining charging time T2 of the terminal down-current section is estimated by linear interpolation method; S13. Theoretical charging time T according to step S9 d ″ and the remaining charging time T2 of step S11, the total remaining charging time is calculated as T d ″+T2; S14. During each charging process, self-learning [C n ,T em ,T2],[C n ,T em ,Q2] forms a dynamic rule base to facilitate subsequent charging table lookup.

2. The method for estimating the remaining charging time for household energy storage according to claim 1 is characterized in that: Calculation method for remaining capacity and charging time at the end of charging; In S14, according to the fuzzy algorithm, it is necessary to train rules and induction [C n ,T em ,T2],[C n ,T em ,Q2]; Among them, S14.1, performs the flow reduction stage judgment; If yes, execute S14.2A. First, query the cell T before current reduction. em , constant current C n ; Then, calculate the charging capacity by current integration and count the charging time; Secondly, when charging is completed and fully charged, store the calculated [C n ,T em ,T2],[C n ,T em ,Q2], when the charging is completed before the full charge, the calculated [C n ,T em ,T2],[C n ,T em ,Q2]; Otherwise, execute S14.2B; first, cumulatively calculate the charging capacity of each stage, and then, when the charging of the stage is completed, store the charging capacity of the corresponding stage; then return to S14.1; In step S11, first, according to [C n , T em ], read the closest [C0, C1], [T em0 , T em1 ]; Then, linear interpolation is used to obtain T2; Through step S9, it is assumed that the original unit time (1min) needs to be counted α, and the current unit time is adjusted to α / ε, and the timer does not need to be reconfigured; In step S5, the capacity of each stage is confirmed, wherein the capacity Q corresponding to the initial charging stage is S :First, query the charging capacity table of each stage to obtain the corresponding capacity Q of each stage S ,Q2,…Q n ; Then, the remaining charging capacity is calculated at the beginning of charging, Q1 = (SOC-SOC s ) / (SOC s +1-SOC)*Q S .

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