Circuit and method for quickly calibrating the remaining power of lithium batteries

Abstract

The present invention discloses a circuit and method for quickly calibrating the remaining power of a lithium battery. The circuit includes a main control chip and a power supply switching circuit, a first voltage sampling circuit and a second voltage sampling circuit. The method includes: obtaining a voltage threshold V corresponding to 10% remaining power of the lithium battery from a constant current discharge characteristic curve of the lithium battery. cap10％ ; When the power supply voltage sampling cycle arrives, determine whether it is in high-power working mode; in different working modes, different voltage sampling circuits are used to sample the actual voltage value V smpl ; The actual voltage value V smpl With voltage threshold V cap10％ Compare, if V smpl <V cap10％ The present invention maintains the combined power supply of the lithium battery and the super capacitor to sample the combined voltage in the high-power working mode, switches to the lithium battery alone to sample the lithium battery voltage in the non-high-power working mode, and can quickly calibrate the remaining power of the lithium battery by comparing it with the voltage threshold, and then decides whether to enable the power consumption reduction processing mechanism to ensure the service life of the battery.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a circuit and method for quickly calibrating the remaining power of a lithium battery. Background Art

[0002] With the development of society, the demand for various energy sources (electricity, heat, water, gas) in production and life is becoming greater and greater. In order to collect, analyze and manage the data uploaded from the metering equipment in real time, energy companies have put forward more intelligent requirements for energy metering equipment. In order to meet these needs, energy metering equipment has added many additional functions as needed, such as electronic metering function (ultrasonic metering, thermal metering, etc.), remote communication function (GPRS, NB-IOT, etc.), local communication function (infrared, RS485, etc.), valve control function, data storage function (EEPROM, FRAM), etc. The power consumption generated by these functions when turned on is very large for battery-powered metering equipment. If these functions are not limited in time, limited in number or even disabled according to the battery status (remaining power or battery voltage) to reduce power consumption, the service life of the battery-powered metering equipment cannot be met. Therefore, it is particularly important to be able to quickly calibrate the remaining battery power and perform corresponding power reduction processing according to the power.

[0003] At present, there are two ways to calibrate the power of lithium batteries:

[0004] The first is to periodically sample the voltage value of the "lithium battery and supercapacitor" in parallel. When the voltage value is lower than the specified threshold, it is considered that the remaining battery power is lower than a certain threshold. Due to the influence of supercapacitor discharge, the sampled voltage value is not the actual voltage value of the lithium battery itself, so there is a lag in the measurement, and the remaining power of the lithium battery cannot be calibrated quickly, resulting in a lag in the activation of the power reduction processing mechanism, and ultimately the service life of the lithium battery cannot be guaranteed.

[0005] The second method is to calculate the remaining battery power based on the power deduction model, that is, to calculate in advance the average power consumption of each function in the metering device during normal operation, and then count and deduct the power based on the actual number of times or usage time of each function. This method is based on the power deduction reference model and does not take into account various combinations of scenarios (different ambient temperatures, self-discharge characteristics of lithium batteries, retry mechanisms for failed business function operations, etc.). Therefore, as the battery usage time increases, the difference between the actual remaining power and the remaining power calculated by the model will become larger and larger. If the model deduction is too fast, the power reduction processing mechanism will be enabled in advance, affecting the normal use of the business functions of the metering equipment; if the model deduction is too slow, the same problem as the first detection method will occur. Summary of the invention

[0006] The present invention provides a circuit and method for quickly calibrating the remaining power of a lithium battery to solve the above technical problems.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] According to a first aspect of an embodiment of the present invention, a circuit for quickly calibrating the remaining power of a lithium battery is provided, which is used in a system powered by a lithium battery and a supercapacitor, including a main control chip and a power supply switching circuit connected to the main control chip, a first voltage sampling circuit for collecting the voltage of the lithium battery, and a second voltage sampling circuit for collecting the combined voltage of the lithium battery and the supercapacitor, wherein the power supply switching circuit is electrically connected to the lithium battery, the supercapacitor, and the main control chip, respectively, the first voltage sampling circuit is connected to the lithium battery, the first sampling control terminal and the first sampling output terminal of the main control chip, respectively, and the second voltage sampling circuit is connected to the supercapacitor, the second sampling control terminal and the second sampling output terminal of the main control chip, respectively.

[0009] Preferably, the power supply switching circuit includes an output interface P1, a P-channel field effect transistor Q5, and a P-channel field effect transistor Q6. The gate of the P-channel field effect transistor Q5 and the gate of the P-channel field effect transistor Q6 are connected to the power supply switching control end of the main control chip through a resistor R20, the drain of the P-channel field effect transistor Q5 is connected to the lithium battery, and the drain of the P-channel field effect transistor Q6 is connected to the supercapacitor through a resistor R15. The three ports of the output interface P1 are respectively connected to the lithium battery, the supercapacitor power supply end and the ground end. Capacitors C4 and C5 are connected in parallel between the lithium battery and the ground end, capacitor C13 is connected between the supercapacitor and the ground end, and capacitor C15 is connected between the lithium battery and the power supply switching control end of the main control chip.

[0010] As a preferred embodiment, the first voltage sampling circuit includes a transistor Q2, a resistor R3 and a resistor R8, the base of the transistor Q2 is connected to the first sampling control terminal of the main control chip through the resistor R6, the emitter of the transistor Q2 is connected to the lithium battery, the collector of the transistor Q2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the resistor R8 and the first sampling output terminal of the main control chip, the other end of the resistor R8 is grounded, and the first sampling output terminal of the main control chip is grounded through the capacitor C10;

[0011] As another preferred embodiment, the first voltage sampling circuit includes a resistor R3 and a resistor R8, one end of the resistor R3 is connected to the lithium battery, the other end of the resistor R3 is connected to one end of the resistor R8 and the first sampling output end of the main control chip, the other end of the resistor R8 is connected to the first sampling control end of the main control chip, and a capacitor C10 is connected between the first sampling output end and the first sampling control end of the main control chip.

[0012] As another preferred embodiment, the first voltage sampling circuit includes a transistor Q2, a resistor R3 and a resistor R8, the base of the transistor Q2 is connected to the first sampling control end of the main control chip through the resistor R6, the emitter of the transistor Q2 is grounded, the collector of the transistor Q2 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R3 and the first sampling output end of the main control chip, the other end of the resistor R3 is connected to the lithium battery, and the first sampling output end of the main control chip is grounded through the capacitor C10.

[0013] As a preferred embodiment, the second voltage sampling circuit includes a transistor Q7, a resistor R16 and a resistor R22, the base of the transistor Q7 is connected to the second sampling control terminal of the main control chip through the resistor R12, the emitter of the transistor Q7 is connected to the supercapacitor, the collector of the transistor Q7 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to one end of the resistor R22 and the second sampling output terminal of the main control chip, the other end of the resistor R22 is grounded, and the second sampling output terminal of the main control chip is grounded through the capacitor C18.

[0014] As another preferred embodiment, the second voltage sampling circuit includes a resistor R16 and a resistor R22, one end of the resistor R16 is connected to the second power supply end, the other end of the resistor R16 is connected to one end of the resistor R22 and the second sampling output end of the main control chip, the other end of the resistor R22 is connected to the second sampling control end of the main control chip, and a capacitor C18 is connected between the second sampling output end and the second sampling control end of the main control chip.

[0015] As another preferred embodiment, the second voltage sampling circuit includes a transistor Q7, a resistor R16 and a resistor R22, the base of the transistor Q7 is connected to the second sampling control terminal of the main control chip through the resistor R6, the emitter of the transistor Q7 is grounded, the collector of the transistor Q7 is connected to one end of the resistor R22, the other end of the resistor R22 is connected to one end of the resistor R16 and the second sampling output terminal of the main control chip, the other end of the resistor R16 is connected to the supercapacitor, and the second sampling output terminal of the main control chip is grounded through the capacitor C18.

[0016] According to a second aspect of an embodiment of the present invention, a method for quickly calibrating the remaining power of a lithium battery is provided. Based on the above circuit for quickly calibrating the remaining power of a lithium battery, the method is used in a system powered by a lithium battery and a supercapacitor, wherein the system is powered by a combination of a lithium battery and a supercapacitor in a normal mode and performs high-power operations including remote communication and switch valve operations; the method comprises the following steps:

[0017] Step 101, according to the specifications of the lithium battery, obtain the battery output voltage threshold V corresponding to the remaining 10% of the lithium battery power from the lithium battery constant current discharge characteristic curve cap10％ ;

[0018] Step 102, when the power supply voltage sampling period arrives, determine whether it is in the high-power working mode, if not, go to step 103, if yes, go to step 104;

[0019] Step 103, the main control chip switches the power supply switching circuit to the lithium battery power supply, and the first voltage sampling circuit samples the voltage of the lithium battery, and obtains the actual voltage value V in the non-high-power working mode through AD conversion. smpl , after sampling is completed, switch back to the lithium battery and supercapacitor combination for power supply;

[0020] Step 104: The second voltage sampling circuit samples the voltage of the lithium battery and the supercapacitor combination, and obtains the actual voltage value V in the high-power working mode through AD conversion. smpl ;

[0021] Step 105: The actual voltage value V smpl The voltage threshold V corresponding to 10% remaining power cap10％ Compare, if V smpl <V cap10％ It is determined that the remaining power of the lithium battery is less than 10%.

[0022] Preferably, step 103 includes the following steps:

[0023] Step 1031, increasing the sampling period of the power supply voltage;

[0024] Step 1032, switching the power supply switching circuit to lithium battery power supply;

[0025] Step 1033, sampling the actual voltage value of the lithium battery in the non-high-power working mode through the first voltage sampling circuit;

[0026] Step 1034, after the voltage sampling is completed, the power supply is switched to the lithium battery and super capacitor combination.

[0027] Preferably, step 104 includes the following steps:

[0028] Step 1041, reducing the sampling period of the power supply voltage;

[0029] Step 1042, switching the power supply switching circuit to a combination of lithium battery and super capacitor power supply;

[0030] Step 1043: sampling the actual voltage value of the lithium battery in the high-power working mode through the second voltage sampling circuit.

[0031] Preferably, in step 105, if it is determined that the remaining power is less than 10%, the system where the lithium battery is located enters a low power consumption working state of non-high power operation behavior.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. According to the constant current discharge characteristics corresponding to the nominal capacity of the lithium battery, by sampling the lithium battery voltage, the remaining power of the lithium battery can be quickly calibrated, and then decide whether to enable the power consumption reduction processing mechanism to achieve the purpose of ensuring the service life of the battery;

[0034] 2. The present invention maintains the combined power supply of lithium battery and super capacitor to sample the combined voltage when the system is in high-power working mode, and switches to lithium battery alone for power supply and samples the lithium battery voltage in non-high-power working mode. The calibration method is faster and more accurate. Compared with the method of only detecting the combined power supply voltage of lithium battery and super capacitor, the problem of not being able to meet the service life of lithium battery due to the lag of power calibration will not occur;

[0035] 3. The present invention maintains the combined power supply of lithium battery and super capacitor to sample the combined voltage when the system is in high-power working mode, and switches to lithium battery alone for power supply and samples the lithium battery voltage in non-high-power working mode. Compared with the method of calculating the remaining power of lithium battery by power reduction model, the voltage of lithium battery is directly collected, which can better reflect the actual discharge voltage and power consumption of lithium battery itself, and then accurately judge the service life, and will not cause the problem of affecting the normal use of the whole metering equipment due to premature activation of power reduction processing mechanism;

[0036] 4. In non-high-power mode, increasing the sampling period of the power supply voltage can effectively reduce power consumption; in high-power mode, reducing the sampling period of the power supply voltage can prevent the lag caused by the long sampling period from causing the system power supply voltage to be pulled down too quickly to the reset voltage threshold of the main control chip, ensuring that the current power supply voltage value can be detected quickly and in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of the structure of a circuit for quickly calibrating the remaining power of a lithium battery according to the present invention;

[0038] Figure 2 A circuit diagram of a power supply switching circuit in a circuit for quickly calibrating the remaining power of a lithium battery according to the present invention;

[0039] Figure 3 A circuit diagram of a first voltage sampling circuit in a circuit for quickly calibrating the remaining power of a lithium battery according to the present invention;

[0040] Figure 4 Another circuit diagram of the first voltage sampling circuit in the circuit for quickly calibrating the remaining power of a lithium battery of the present invention;

[0041] Figure 5 Another circuit diagram of the first voltage sampling circuit in the circuit for quickly calibrating the remaining power of a lithium battery of the present invention;

[0042] Figure 6 A circuit diagram of a second voltage sampling circuit in a circuit for quickly calibrating the remaining power of a lithium battery according to the present invention;

[0043] Figure 7 Another circuit diagram of the second voltage sampling circuit in the circuit for quickly calibrating the remaining power of a lithium battery of the present invention;

[0044] Figure 8 Another circuit diagram of the second voltage sampling circuit in the circuit for quickly calibrating the remaining power of a lithium battery of the present invention;

[0045] Fig. 9 A flow chart of a method for quickly calibrating the remaining power of a lithium battery according to the present invention;

[0046] Fig.10 A flow chart of step 103 in the method for quickly calibrating the remaining power of a lithium battery of the present invention;

[0047] Fig.11 A flow chart of step 104 in the method for quickly calibrating the remaining power of a lithium battery of the present invention.

[0048] In the figure, 1-main control chip, 2-power supply switching circuit, 3-first voltage sampling circuit, 4-second voltage sampling circuit. DETAILED DESCRIPTION

[0049] The present invention will be described in detail below in conjunction with the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0050] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0051] like Figure 1As shown, a circuit for quickly calibrating the remaining power of a lithium battery includes a main control chip 1 and a power supply switching circuit 2 connected to the main control chip 1, a first voltage sampling circuit 3 for collecting the voltage of a lithium battery, and a second voltage sampling circuit 4 for collecting the voltage of a lithium battery and a super capacitor combination, wherein the power supply switching circuit 2 is electrically connected to the lithium battery power supply end (BAT_PWR), the super capacitor power supply end (SPC), and the power supply switching control end (MCU-SPC-PWR-CTL) of the main control chip 1, respectively, the first voltage sampling circuit 3 is respectively connected to the lithium battery, the first sampling control end (MCU-LI-PWR-AD-CTL) and the first sampling output end (MCU-LI-PWR-AD) of the main control chip 1, and the second voltage sampling circuit 4 is respectively connected to the super capacitor, the second sampling control end (MCU-SPC-PWR-AD-CTL) and the second sampling output end (MCU-SPC-PWR-AD) of the main control chip 1. The present invention can be used in systems powered by lithium batteries and super capacitors, such as metering equipment systems.

[0052] In high-power mode, the main control chip 1 switches the power supply switching circuit 2 to lithium battery power supply, and samples the actual voltage value of the lithium battery in the high-power working mode through the first voltage sampling circuit 3; in non-high-power mode, the main control chip 1 switches the power supply switching circuit 2 to a combination of lithium battery and supercapacitor power supply, and samples the actual voltage values ​​of the lithium battery and supercapacitor in the high-power working mode through the second voltage sampling circuit 4.

[0053] like Figure 2 As shown, the power supply switching circuit 2 includes an output interface P1, a P-channel field effect transistor Q5, and a P-channel field effect transistor Q6. The gate of the P-channel field effect transistor Q5 and the gate of the P-channel field effect transistor Q6 are connected to the power supply switching control end of the main control chip 1 through a resistor R20, the drain of the P-channel field effect transistor Q5 is connected to the lithium battery, and the drain of the P-channel field effect transistor Q6 is connected to the super capacitor through a resistor R15. The three ports of the output interface P1 are respectively connected to the lithium battery, the super capacitor and the ground terminal, capacitors C4 and C5 are connected in parallel between the lithium battery and the ground terminal, capacitor C13 is connected between the super capacitor and the ground terminal, and capacitor C15 is connected between the lithium battery and the power supply switching control end of the main control chip 1.

[0054] Regarding the first voltage sampling circuit 3, one implementation of the present invention is as follows: Figure 3As shown, the first voltage sampling circuit 3 includes a transistor Q2, a resistor R3 and a resistor R8. The base of the transistor Q2 is connected to the first sampling control end of the main control chip 1 through the resistor R6, the emitter of the transistor Q2 is connected to the lithium battery, the collector of the transistor Q2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the resistor R8 and the first sampling output end of the main control chip 1, the other end of the resistor R8 is grounded, and the first sampling output end of the main control chip 1 is grounded through the capacitor C10.

[0055] Regarding the first voltage sampling circuit 3, another implementation of the present invention is as follows: Figure 4 As shown, the first voltage sampling circuit 3 includes a resistor R3 and a resistor R8, one end of the resistor R3 is connected to the lithium battery, the other end of the resistor R3 is connected to one end of the resistor R8 and the first sampling output end of the main control chip 1, the other end of the resistor R8 is connected to the first sampling control end of the main control chip 1, and a capacitor C10 is connected between the first sampling output end and the first sampling control end of the main control chip 1

[0056] Regarding the first voltage sampling circuit 3, another implementation of the present invention is as follows: Figure 5 As shown, the first voltage sampling circuit 3 includes a transistor Q2, a resistor R3 and a resistor R8. The base of the transistor Q2 is connected to the first sampling control end of the main control chip 1 through the resistor R6, the emitter of the transistor Q2 is grounded, the collector of the transistor Q2 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R3 and the first sampling output end of the main control chip 1, the other end of the resistor R3 is connected to the lithium battery, and the first sampling output end of the main control chip 1 is grounded through the capacitor C10.

[0057] Regarding the second voltage sampling circuit 4, one implementation of the present invention is as follows: Figure 6 As shown, the second voltage sampling circuit 4 includes a transistor Q7, a resistor R16 and a resistor R22. The base of the transistor Q7 is connected to the second sampling control end of the main control chip 1 through the resistor R12, the emitter of the transistor Q7 is connected to the super capacitor, the collector of the transistor Q7 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to one end of the resistor R22 and the second sampling output end of the main control chip 1, the other end of the resistor R22 is grounded, and the second sampling output end of the main control chip 1 is grounded through the capacitor C18.

[0058] Regarding the second voltage sampling circuit 4, another implementation of the present invention is as follows: Figure 7As shown, the second voltage sampling circuit 4 includes a resistor R16 and a resistor R22, one end of the resistor R16 is connected to the supercapacitor, the other end of the resistor R16 is connected to one end of the resistor R22 and the second sampling output end of the main control chip 1, the other end of the resistor R22 is connected to the second sampling control end of the main control chip 1, and a capacitor C18 is connected between the second sampling output end and the second sampling control end of the main control chip 1.

[0059] Regarding the second voltage sampling circuit 4, another implementation of the present invention is as follows: Figure 8 As shown, the second voltage sampling circuit 4 includes a transistor Q7, a resistor R16 and a resistor R22. The base of the transistor Q7 is connected to the second sampling control end of the main control chip 1 through the resistor R6, the emitter of the transistor Q7 is grounded, the collector of the transistor Q7 is connected to one end of the resistor R22, the other end of the resistor R22 is connected to one end of the resistor R16 and the second sampling output end of the main control chip 1, the other end of the resistor R16 is connected to the super capacitor, and the second sampling output end of the main control chip 1 is grounded through the capacitor C18.

[0060] The above three forms of first voltage sampling circuits 3 and three forms of second voltage sampling circuits 4 can be randomly selected and combined, and can all realize the main control chip 1 to control the selection of sampling circuits in high-power mode and non-high-power mode, so as to quickly and real-time detect the power supply voltage value of the current state.

[0061] Based on the above circuit for quickly calibrating the remaining power of a lithium battery, the present invention proposes a method for quickly calibrating the remaining power of a lithium battery, which is used in a system powered by a lithium battery and a supercapacitor, wherein the system is powered by a combination of a lithium battery and a supercapacitor in a normal mode and performs high-power operations including remote communication and switch valve operations; Fig. 9 As shown, the following steps are included:

[0062] Step 101, according to the specifications of the lithium battery, obtain the battery output voltage threshold V corresponding to the remaining 10% of the lithium battery power from the lithium battery constant current discharge characteristic curve cap10％ .

[0063] The discharge constant current value I corresponding to the nominal capacity of the lithium battery can be obtained from the constant current discharge characteristic curve described in the lithium battery specification. dis The voltage threshold V corresponding to 10% remaining power cap10％ For example, in the specification of a lithium battery with a nominal capacity of 8.5Ah and a nominal voltage of 3.6V, find its constant current discharge characteristic curve to get I dis 4mA, V cap10％ =3.4V.

[0064] Step 102 , when the power supply voltage sampling period arrives, determine whether it is in the high-power working mode, if not, go to step 103 , if yes, go to step 104 .

[0065] The switching of the system power supply mode (lithium battery power supply or lithium battery + super capacitor power supply) and the on / off of the voltage sampling circuit are controlled by the main control chip 1; when the power supply voltage sampling is not performed, the entire system is powered by lithium battery + super capacitor. At the same time, in order to reduce power consumption, the power supplies of the lithium battery and super capacitor voltage sampling circuits are both turned off.

[0066] When the power supply voltage sampling cycle arrives, it will first switch to the corresponding system power supply mode according to the current working mode (non-high power / high power mode). In the non-high power working mode, the main control chip 1 switches the power supply switching circuit 2 to lithium battery power supply, and turns on the power of the first voltage sampling circuit 3 that only collects the lithium battery voltage; in the high power working mode, the main control chip 1 maintains the power supply of the lithium battery and super capacitor combination, and turns on the power of the second voltage sampling circuit 4 that collects the voltage of the lithium battery and super capacitor combination.

[0067] Step 103, the main control chip switches the power supply switching circuit to the lithium battery power supply, and the first voltage sampling circuit 3 samples the voltage of the lithium battery, and obtains the actual voltage value V in the non-high-power working mode through AD conversion. smpl After sampling, the power supply is switched back to the lithium battery and supercapacitor combination.

[0068] Due to the influence of supercapacitor discharge, the sampled voltage value is not the actual voltage value of the lithium battery itself, so there is a lag in the measurement, and the remaining power of the lithium battery cannot be calibrated quickly, resulting in a lag in the activation of the power reduction processing mechanism. Therefore, in the non-high-power working mode, that is, the valve switching operation, the remote communication module and other high-power component operations are no longer executed, the main control chip 1 switches the power supply mode from the original lithium battery and supercapacitor combination power supply mode to the lithium battery power supply mode, and the main control chip 1 controls the start of a sampling circuit that only samples the lithium battery voltage, which is used for voltage sampling of the metering equipment in the non-high-power working mode.

[0069] According to the system wake-up current I wake (generally 1 mA), the total resistance R of the first voltage sampling circuit 3 can be calculated by the formula smpl : Among them U n is the nominal voltage of the lithium battery. Therefore, in non-high-power operation mode, by adjusting R smpl It can ensure that the entire system works under the Idis constant current load during voltage sampling, and can ensure that the entire system is under Idis constant current load. dis Sampling of lithium battery voltage under constant current load.

[0070] Specifically, Fig.10 As shown, step 103 may include the following steps:

[0071] Step 1031, increase the sampling period of the power supply voltage. To reduce power consumption, the sampling period of the power supply voltage in the non-high-power mode is greater than the sampling period of the power supply voltage in the high-power mode. The sampling frequency in the two modes, i.e., the reciprocal of the sampling period, is in the order of hours and is determined by the system of the entire metering device.

[0072] Step 1032, switching the power supply switching circuit 2 to lithium battery power supply.

[0073] Step 1033 , sampling the actual voltage value of the lithium battery in the non-high power working mode through the first voltage sampling circuit 3 .

[0074] Step 1034, after the voltage sampling is completed, the power supply is switched to the lithium battery and super capacitor combination. After the sampling is completed, the power supply of the first voltage sampling circuit 3 will be turned off, and the main control chip 1 will switch the system power supply mode back to the power supply mode of the lithium battery and super capacitor combination.

[0075] Step 104, according to the second voltage sampling circuit 4, obtain the actual voltage value V in the high-power working mode through AD conversion smpl .

[0076] When the power supply voltage sampling is triggered, if the system is in the high-power working mode, the power supply mode of the system will not be switched, that is, it will remain in the power supply mode of the lithium battery and super capacitor combination. At the same time, the second voltage sampling circuit 4 is turned on under the control of the main control chip 1 to perform voltage sampling, and then determine the remaining power of the lithium battery.

[0077] Specifically, Fig.11 As shown, step 104 may include the following steps:

[0078] Step 1041, reduce the sampling period of the power supply voltage. In high-power mode, in order to prevent the system power supply voltage from being pulled down to the reset voltage threshold of the MCU too quickly due to the hysteresis caused by the long sampling period, the sampling period of the power supply voltage will be accelerated to ensure that the current power supply voltage value can be detected quickly and in real time.

[0079] Step 1042, switching the power supply switching circuit 2 to a combination of lithium battery and super capacitor for power supply.

[0080] Step 1043, sampling the actual voltage value of the lithium battery and super capacitor combination in the high-power working mode through the second voltage sampling circuit 4. After the sampling is completed, the power supply of the second voltage sampling circuit 4 is turned off.

[0081] Step 105: The actual voltage value V smpl The voltage threshold V corresponding to 10% remaining power cap10％ Compare, if V smpl <V cap10％ It is determined that the remaining power of the lithium battery is less than 10%.

[0082] Finally, by setting the voltage sampling value V smpl With voltage threshold V cap10％ The remaining capacity of the lithium battery can be calibrated by comparison.

[0083] If V smpl <V cap10％ , it is considered that the remaining power of the lithium battery is less than 10%, so the power reduction processing mechanism is turned on, and the system where the lithium battery is located enters a low-power working state without high-power operation to ensure the service life of the lithium battery. Here, the low-power working state without high-power operation includes but is not limited to: no remote communication, no valve opening and closing operation, etc.

[0084] The present invention can quickly calibrate the remaining power of the lithium battery by sampling the lithium battery voltage according to the constant current discharge characteristics corresponding to the nominal capacity of the lithium battery, and then decide whether to enable the power consumption reduction processing mechanism to achieve the purpose of ensuring the service life of the battery.

[0085] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present invention are indicated by the claims of the present application.

[0086] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A circuit for quickly calibrating the remaining power of a lithium battery, used in a system powered by a lithium battery and a supercapacitor, characterized in that: It includes a main control chip and a power supply switching circuit connected to the main control chip, a first voltage sampling circuit for collecting the voltage of a lithium battery, and a second voltage sampling circuit for collecting the combined voltage of a lithium battery and a super capacitor, wherein the power supply switching circuit is electrically connected to the lithium battery, the super capacitor, and the main control chip, respectively, the first voltage sampling circuit is connected to the lithium battery, the first sampling control terminal and the first sampling output terminal of the main control chip, respectively, and the second voltage sampling circuit is connected to the super capacitor, the second sampling control terminal and the second sampling output terminal of the main control chip, respectively; Among them, the main control chip is used to control the switching of the system power supply mode and the on / off of the voltage sampling circuit. In the non-high-power working mode, the main control chip switches the power supply switching circuit to lithium battery power supply, increases the sampling period of the power supply voltage, and samples the actual voltage value of the lithium battery in the non-high-power working mode through the first voltage sampling circuit. After the voltage sampling is completed, it switches to the combination of lithium battery and supercapacitor power supply.

2. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The power supply switching circuit includes an output interface P1, a P-channel field effect transistor Q5 and a P-channel field effect transistor Q6. The gate of the P-channel field effect transistor Q5 and the gate of the P-channel field effect transistor Q6 are connected to the power supply switching control end of the main control chip through a resistor R20. The drain of the P-channel field effect transistor Q5 is connected to a lithium battery. The drain of the P-channel field effect transistor Q6 is connected to a super capacitor through a resistor R15. The three ports of the output interface P1 are respectively connected to the lithium battery, the super capacitor and the ground terminal. Capacitors C4 and C5 are connected in parallel between the lithium battery and the ground terminal. Capacitor C13 is connected between the super capacitor and the ground terminal. Capacitor C15 is connected between the lithium battery and the power supply switching control end of the main control chip.

3. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The first voltage sampling circuit includes a transistor Q2, a resistor R3 and a resistor R8. The base of the transistor Q2 is connected to the first sampling control end of the main control chip through the resistor R6, the emitter of the transistor Q2 is connected to the lithium battery, the collector of the transistor Q2 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the resistor R8 and the first sampling output end of the main control chip, the other end of the resistor R8 is grounded, and the first sampling output end of the main control chip is grounded through the capacitor C10.

4. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The first voltage sampling circuit includes a resistor R3 and a resistor R8, one end of the resistor R3 is connected to the lithium battery, the other end of the resistor R3 is connected to one end of the resistor R8 and the first sampling output end of the main control chip, the other end of the resistor R8 is connected to the first sampling control end of the main control chip, and a capacitor C10 is connected between the first sampling output end and the first sampling control end of the main control chip.

5. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The first voltage sampling circuit includes a transistor Q2, a resistor R3 and a resistor R8. The base of the transistor Q2 is connected to the first sampling control end of the main control chip through the resistor R6, the emitter of the transistor Q2 is grounded, the collector of the transistor Q2 is connected to one end of the resistor R8, the other end of the resistor R8 is connected to one end of the resistor R3 and the first sampling output end of the main control chip, the other end of the resistor R3 is connected to the lithium battery, and the first sampling output end of the main control chip is grounded through the capacitor C10.

6. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The second voltage sampling circuit includes a transistor Q7, a resistor R16 and a resistor R22. The base of the transistor Q7 is connected to the second sampling control terminal of the main control chip through the resistor R12, the emitter of the transistor Q7 is connected to the supercapacitor, the collector of the transistor Q7 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to one end of the resistor R22 and the second sampling output terminal of the main control chip, the other end of the resistor R22 is grounded, and the second sampling output terminal of the main control chip is grounded through the capacitor C18.

7. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The second voltage sampling circuit includes a resistor R16 and a resistor R22, one end of the resistor R16 is connected to the supercapacitor, the other end of the resistor R16 is connected to one end of the resistor R22 and the second sampling output end of the main control chip, the other end of the resistor R22 is connected to the second sampling control end of the main control chip, and a capacitor C18 is connected between the second sampling output end and the second sampling control end of the main control chip.

8. The circuit for quickly calibrating the remaining power of a lithium battery according to claim 1, characterized in that: The second voltage sampling circuit includes a transistor Q7, a resistor R16 and a resistor R22. The base of the transistor Q7 is connected to the second sampling control end of the main control chip through the resistor R6, the emitter of the transistor Q7 is grounded, the collector of the transistor Q7 is connected to one end of the resistor R22, the other end of the resistor R22 is connected to one end of the resistor R16 and the second sampling output end of the main control chip, the other end of the resistor R16 is connected to the super capacitor, and the second sampling output end of the main control chip is grounded through the capacitor C18.

9. A method for quickly calibrating the remaining power of a lithium battery, characterized in that: The circuit for quickly calibrating the remaining power of a lithium battery according to any one of claims 1 to 8 is used in a system powered by a lithium battery and a supercapacitor, wherein the system is powered by a combination of a lithium battery and a supercapacitor in a normal mode and performs high-power operations including remote communication and switch valve operations; comprising the following steps: Step 101, according to the specifications of the lithium battery, obtain the battery output voltage threshold V corresponding to the lithium battery when the remaining power of the lithium battery is 10% from the constant current discharge characteristic curve of the lithium battery cap10% ; Step 102, when the power supply voltage sampling period arrives, determine whether it is in the high-power working mode, if not, go to step 103, if yes, go to step 104; Step 103, the main control chip switches the power supply switching circuit to the lithium battery power supply, samples the voltage of the lithium battery according to the first voltage sampling circuit, and obtains the actual voltage value V in the non-high-power working mode through AD conversion. smpl , after sampling is completed, switch back to the lithium battery and supercapacitor combination for power supply; Step 104: Sample the voltage of the lithium battery and the supercapacitor combination according to the second voltage sampling circuit, and obtain the actual voltage value V in the high-power working mode through AD conversion. smpl ; Step 105: The actual voltage value V smpl The voltage threshold V corresponding to 10% remaining power cap10% Compare, if V smpl <V cap10% It is determined that the remaining power of the lithium battery is less than 10%.

10. The method for quickly calibrating the remaining power of a lithium battery according to claim 9, characterized in that: The step 103 comprises the following steps: Step 1031, increasing the sampling period of the power supply voltage; Step 1032, switching the power supply switching circuit to lithium battery power supply; Step 1033, sampling the actual voltage value of the lithium battery in the non-high-power working mode through the first voltage sampling circuit; Step 1034, after the voltage sampling is completed, the power supply is switched to the lithium battery and super capacitor combination.

11. The method for quickly calibrating the remaining power of a lithium battery according to claim 9, characterized in that: The step 104 includes the following steps: Step 1041, reducing the sampling period of the power supply voltage; Step 1042, switching the power supply switching circuit to a combination of lithium battery and super capacitor for power supply; Step 1043: sampling the actual voltage value of the lithium battery in the high-power working mode through the second voltage sampling circuit.

12. The method for quickly calibrating the remaining power of a lithium battery according to any one of claims 9 to 11, characterized in that: In step 105, if it is determined that the remaining power is less than 10%, the system enters a low power consumption working state without high power operation behavior.

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