Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that, in the embodiments of the present invention, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.
The embodiment of the invention provides a charging method, a charging chip and terminal equipment, which can improve the charging utilization rate.
The terminal device related to the embodiment of the invention can be electronic devices such as a mobile phone, a tablet computer, a notebook computer, a palm computer, a vehicle-mounted terminal device, a wearable device, an Ultra-Mobile Personal Computer (UMPC), a netbook or a Personal digital assistant (Personal DIGITAL ASSISTANT, PDA) and the like. The wearable device may be an intelligent watch, an intelligent bracelet, a watch phone, an intelligent foot ring, an intelligent earring, an intelligent necklace, an intelligent earphone, etc., and the embodiment of the invention is not limited.
The charging method provided by the embodiment of the invention is particularly suitable for terminal equipment with smaller battery capacity, such as wearable equipment.
At present, the wearable equipment is miniaturized more and more, the battery space in the wearable equipment is smaller, the battery capacity is difficult to improve, but the functions of the wearable equipment are richer and more, and the wearable equipment has more application functions with large power consumption (such as photographing, video chat, video recording and the like) so that the endurance of the wearable equipment is poorer and worse, and therefore, the utilization rate of the battery is improved as much as possible during charging.
The battery volume of the wearable device is usually smaller, so that the internal resistance of the battery is larger, the internal resistance of the small battery within 1000mAh in an actual product is more than 250 milliohms, the battery can generate floating pressure when being charged, for example, 0.5A battery is used for charging, 0.5 x 0.25=0.125V floating pressure can be generated, and the maximum floating pressure in the charging process is equivalent to 0.125V, so that the battery is difficult to be fully charged, and the utilization rate is lower.
Another disadvantage of small battery capacity is that the off-current required to charge the battery is small, and typically the off-current required to charge the battery is less than 0.2C. (C refers to the capacity of the battery). Such as 800mAh, requires a full off current of 0.2C, i.e., 16mAh, and there is currently no such small off current charging chip on the market. The current cut-off current of the charging of the general charging chip in the market is generally above 50mA, namely, the cut-off condition of the charging is not met, so that the battery with small capacity cannot be fully charged.
In order to improve the utilization rate of the battery, a charging chip with small charging cut-off current is selected in the related technology, for example, BQ25618 of TI is selected, and the cut-off of the battery can be 20-30mA. The disadvantage of this approach is that in the platform solution of the wearable device (such as the solution of the telephone watch), the telephone watch is generally provided with a charging chip, and if a charging chip is additionally added, the cost of the product is increased, and the space of the telephone watch is occupied, so that the solution is rarely applied. Practical tests show that even if a charging chip with small cut-off current is used, the improvement of the battery utilization rate is limited, and the battery can be charged and cut-off quickly due to the fact that floating pressure generated when the internal resistance of the battery is large and the battery is charged is large.
The charging method provided by the embodiment of the invention can solve the problems and improve the utilization rate of the battery.
The implementation main body of the charging method provided by the embodiment of the invention may be the terminal device, or may be a functional module and/or a functional entity capable of implementing the charging method in the terminal device, which may be specifically determined according to actual use requirements, and the embodiment of the invention is not limited. The charging method provided by the embodiment of the invention is exemplified by a terminal device.
The embodiment of the invention provides a charging method, which comprises N different charging stages, wherein the N different charging stages are divided according to electric quantity parameters of a battery, the N different charging stages charge the battery by adopting different charging currents, and N is an integer greater than or equal to 2.
The above-mentioned charge parameter is used to characterize the charge of the battery.
The charging stage 1 is charged to a preset electric quantity parameter by a maximum charging current value allowed by the battery, the battery is charged to a full charge state from the preset electric quantity parameter in the charging stage 2 to the charging stage N, the charging current value of each charging stage in the charging stage 2 to the charging stage N is gradually decreased, the charging current value of the charging stage N is smaller than or equal to the preset current value, and the preset current value is determined according to the maximum allowed floating pressure and the internal resistance of the battery.
In the embodiment of the invention, the battery can be charged in N different charging stages, wherein the N different charging stages are divided according to the electric quantity parameters of the battery, the N different charging stages charge the battery by adopting different charging currents, and N is an integer larger than or equal to 2, wherein the 1 st charging stage charges the battery to the preset electric quantity parameters according to the maximum allowable charging current value of the battery, the charging current value of each charging stage from the preset electric quantity parameters to the charging stage from the 2 nd charging stage to the N charging stage is gradually decreased, and the charging current value of the N charging stage is smaller than or equal to the preset current value which is determined according to the allowable maximum floating pressure and the internal resistance of the battery. According to the scheme, the current value of each charging stage of the flushing section from the 2 nd charging stage to the N th charging stage is gradually decreased, the charging current value of the last constant current charging stage is smaller than or equal to a preset current value, the preset current value is determined according to the maximum allowed float pressure and the internal resistance of the battery, and thus the float pressure generated during charging is not larger than the maximum allowed float pressure, the generated float pressure is smaller, the maximum utilization of the battery capacity is ensured, and the utilization rate of the battery is improved.
Alternatively, the electrical parameter may be an electrical percentage, or the electrical parameter may be a voltage value.
In the embodiment of the invention, one possible implementation manner is that the charging stage can be divided according to the electric quantity percentage. Alternatively, the charging phase may be divided with reference to a specific method among the following power control methods.
Another possible implementation is that the charging phases can be divided according to the voltage values. Alternatively, the charging phase may be divided with reference to a specific method among the following voltage control methods.
Optionally, the preset current value is determined according to a quotient of the allowed maximum float and the internal resistance of the battery.
Where there are decimal places, the rounding up may be done.
Optionally, the value of N is determined according to the internal resistance of the battery and the allowable maximum internal resistance.
Optionally, the quotient of the internal resistance of the battery and the maximum internal resistance allowed is rounded up to obtain a value N, n=n+1.
Optionally, the charging current value of each charging phase is reduced by the same amount in the N charging phases.
Optionally, the decrease in the charging current value is obtained according to the following formula:
A=(Imax-IN)/(N-1);
Wherein, A represents a charging current value decreasing amount, Imax represents a maximum charging current value, IN represents a charging current value at an N-th stage, and N represents a total number of charging stages.
The principle of the charging method provided by the embodiment of the invention is as follows:
The internal resistance of the battery is related to the volume of the battery, and the larger the volume is, the smaller the internal resistance is. In practical tests, the battery internal resistance has a certain relation with the battery voltage, and the higher the battery voltage is, the larger the battery internal resistance is, because the charging process of the battery is the overcharge of positively charged lithium ions transferred from the negative electrode to the positive electrode, when the battery voltage is high, the voltage of the negative electrode is close to 0, and at the moment, the lithium ions are few, so that the internal resistance of the transfer of the lithium ions to the positive electrode is increased.
According to ohm law, the battery must generate floating pressure during charging because of the internal resistance of the battery, the traditional charging mode is to charge at constant current and then enter constant voltage, in the whole charging process, the battery can bear the maximum charging current, and then the battery has floating pressure during the whole charging process, the floating pressure can lead to the advanced stop of charging, and if the internal resistance of the battery is large, the battery can not be fully charged.
As shown in fig. 1, the charging curve of the conventional charging mode is shown, in the whole charging curve, constant-current charging is performed first, then constant-voltage charging is performed (two charging processes are separated by a dotted line in fig. 1), the whole process is performed by using the maximum charging current which can be borne by the battery, and if the internal resistance of the battery is large, a charging virtual voltage is provided in the whole process.
For example, when the internal resistance of the battery is 250 milliohms and the charging current is 500mA, the maximum float voltage generated by the battery during the charging process is 0.25×0.5=0.125V, and this float voltage cannot be completely eliminated during the charging process, because the charging process is performed at the maximum charging current that the battery can withstand.
In order to reduce the charging floating pressure, the invention provides a segmented constant-current charging mode, and the charging current can be actively reduced through software control when the battery voltage is relatively high or the electric quantity is relatively high, so that the charging enters a constant-current stage with small current.
Fig. 2 shows a charging curve of the charging method according to the embodiment of the present invention, which may be referred to as a segmented constant current charging method. As shown in fig. 2, the charging current of 5 charging stages is sequentially reduced (the charging current of each stage is denoted as I1、I2、I3、I4 and I5 in the figure), and each time the charging current is reduced, the floating voltage generated during charging can be reduced, so as to achieve the purpose of fully charging the battery to the greatest extent.
As shown in fig. 3, the charging method provided by the embodiment of the invention includes:
101. the number of charging phases N is determined.
In the embodiment of the present invention, the first charging stage of the N charging stages may be a stage of charging with the maximum charging current, and the 2 nd charging stage to the N th charging stage may be referred to as a stage of segmented constant current.
Because the floating pressure is greatly related to the internal resistance of the battery, the internal resistance of the battery within 50 milliohms actually measured has small influence on the floating pressure, and the internal resistance larger than 50 milliohms has obvious influence on the floating pressure, so that the number of times N of the segmented constant current is determined by the quotient obtained by dividing the actual internal resistance value R of the battery by 50 milliohms, wherein n=n+1.
Where the quotient of the actual internal resistance value R of the battery divided by 50 milliohms has a decimal, uniformly rounded up (i.e., rounded 1 in).
For example, assuming a battery internal resistance of 220 milliohms divided by 50 milliohms 4.4, rounded by 1 to 5, a 5-segment constant current may be used, with an N value of 5.
102. The current for each phase is determined.
According to actual debugging test experience, voltage can fall back after the battery is actually charged, the fall-back amplitude can be different according to different internal resistances of the battery in general, and the fall-back amplitude can exceed 100mV under the condition of some fall-back amplitudes. In practical tests, if the drop-back amplitude is between 40mV and 50mV, the battery is generally in a full state (full battery means that the battery is discharged by using a current of 0.2C after the battery is charged, and the discharging time is not less than 5 hours).
Based on the above principle, to ensure that the battery is full, a value of less than 60mV may be chosen as the maximum allowed float.
Alternatively, less than 30mV-40mV may be selected as an acceptable float pressure.
For example, a preset current value may be obtained by dividing 30mV by the internal resistance of the battery using 30mV as the maximum allowable float, and the current value of the last charging stage may be less than or equal to the preset current value. Assuming a battery internal resistance of 200 milliohms, the current IN for the last charging phase is 30mV divided by 200 milliohms, yielding 150mA. After the current IN of the last constant current charging stage is determined, the current value of each constant current is reduced by a value A obtained by dividing the maximum charging current Imax allowed by the battery by IN by N, and the current value of each stage in the stages of segmenting the constant current (namely the 2 nd to the N th charging stages) is Imax -A x N.
For example, if the internal resistance of one battery is 200 milliohms and the maximum charging current is 800mA, the number of times of the segmented constant current n=200/50=4, that is, there are 5 charging phases in total.
Wherein, the current in the nth charging stage is 0.03V/0.2 ohm=0.15a=150ma, then a= (800 mA-150 mA)/4=162 mA.
The currents for the 5 charging phases are then respectively:
I1=800mA;
I2=800mA-162mA*1=638mA;
I3=800mA-162mA*2=476mA;
I4=800mA-162mA*3=314mA;
I5=150mA。
After calculating I1、I2、I3、I4 and I5, the charging currents corresponding to the respective phases may be controlled at the respective charging phases to perform charging.
103. And selecting a current value closest to the determined sectional current to charge according to the current setting gear of the actual charging chip.
In the embodiment of the invention, two specific methods for controlling the charging logic are provided, namely a first electric quantity control method which uses the electric quantity percentage as a basis for dividing the charging stage, and a second electric quantity control method which uses the voltage value as a basis for dividing the charging stage.
The two types of logic for controlling charging are described separately below.
First, a method for controlling electric quantity.
When the electric quantity control method is used for charging, the electric quantity meter is required to be arranged in the terminal equipment, the charging control system is shown in fig. 4, and the electric quantity meter comprises a controller, a charging module, an electric quantity meter and a battery, wherein the electric quantity meter and the charging module are connected with the battery, the controller is connected with the electric quantity meter and the charging module, and the controller can read electric quantity information of the battery through the electric quantity meter, so that charging current of the charging module is controlled.
The specific control method comprises the following steps:
201. the percentage of the amount of charge into the constant voltage charge was determined by the conventional charging method.
By way of example, the charging method shown in fig. 1 may be used to determine the percentage of charge m% that typically goes from a constant current charging phase to a constant voltage charging phase. The percentage of charge typically entering constant voltage charge is between 70% -85%.
Alternatively, in the embodiment of the present invention, m% may take any value from 70% to 85%.
202. A range of charge percentages for each charging phase is determined, as well as a charging current value.
After determining m%, the amount of electricity between (m% -10%) -94% can be divided into N segments, i.e. 94% -100% of the nth step, as the nth charging stage.
Illustratively, N-1 segments are equally divided with (m% -10%) -94% of this segment of power, resulting in a value of b for each segment, assuming that m% = 80% of the test, N is equal to 4, and the power per step is (94% -80% + 10%)/3 = 8%.
The control logic may be:
the 1 st charging stage is that when the battery power is 0% -70%, 800mA is used for charging current;
The 2 nd charging stage, when the battery power is 70% -78%, the charging current is 638mA;
the 3 rd charging stage, when the battery power is 78% -87%, the charging current is 476mA;
the 4 th charging stage, when the battery power is 87% -94%, the charging current is 314mA;
And in the 5 th charging stage, when the battery charge is 94% -100%, the charging current is 150mA.
The battery power percentage range determined by the above method, and the charging current value are only exemplary, and may be actually adjusted according to the requirement.
In the following, the charging effect that can be achieved by the above-described charging method will be described by taking the example of charging the telephone wristwatch.
The rated battery capacity of the telephone watch is 820mAh, the actual battery capacity is 840mAh, the internal resistance of the battery is 170-200 mOhm, the rated battery voltage is 4.4V, and the maximum charging current is 800mA. Then, the last-gear charging current is 30mV/200 milliohms=150mA, and through test, if the battery is charged by a common constant voltage and constant current charging method, when the electric quantity of the battery reaches about 80%, the battery is changed from a constant voltage to a constant current, the value of m% is 80%, and then 70% -94% is divided into 3 sections, so that the electric quantity added in each stage is 8%.
The segmented charge current can be derived as follows:
in the 1 st charging stage, when the battery power is 0% -70%, the charging current is 800Ma.
And in the 2 nd charging stage, when the battery power is 70% -78%, the charging current is 638mA according to the unit of the charging chip, and the actual value is 650mA.
And 3, in the charging stage, 476mA is used for charging current when the electric quantity of the battery is 78-87%, and 475mA is actually taken according to the current gear of the charging chip.
And in the 4 th charging stage, when the battery power is 87% -94%, the charging current is 314mA, and the actual value is 325mA.
And 5, in the charging stage, when the battery charge is 94% -100%, 150mA is used for charging current.
Taking the example of charging the telephone watch, the obtained charging curve can be shown in fig. 5, the fully charged battery comprehensive tester can test the electric quantity, the test result is shown in fig. 6, the electric quantity discharged by the battery is 831mAh, and the rated capacity of the battery is achieved.
And the telephone watch is charged by adopting a traditional charging mode, and the obtained charging curve is shown in fig. 7. The test result of the electric quantity is shown in fig. 8, and the electric quantity discharged by the battery is 781mAh.
As can be seen from fig. 6 and 8, the charging curve of the conventional charging method only discharges about 781mAh after full charge, which is less than 831mAh in the embodiment of the present invention by 50mAh. As can be seen from the results obtained by practical implementation, compared with the traditional charging method, the charging method provided by the embodiment of the invention can improve the charging quantity, so that the utilization rate of the battery is greatly improved.
Second, voltage control method
The voltage control method can eliminate the need of setting an electricity meter in the terminal device, and the charging control system thereof is shown in fig. 9, and comprises a controller, a charging module and a battery, wherein the controller is connected with the battery and the charging module, the charging module is connected with the battery, the controller is provided with an analog-to-digitaldonverter (ADC) interface which can read the battery voltage (the device needing to be charged can support the function generally), and the controller can control the charging module to adjust the charging current.
301. The voltage value a for entering the constant voltage charge is determined by a conventional charging method.
By way of example, the voltage value a for a constant-current charging phase into a constant-voltage charging phase can be determined using the charging method shown in fig. 1.
After a is measured, the rated voltage of the battery is b, the last step is 30mV-40mV, and the electric quantity between a- (b-40 mV) is divided into n-1 sections, namely, the nth step is (b-40 mV) -b, namely, the last charging stage is (b-40 mV) -b.
The last step value of 30-40mV is that the normal voltage of the lithium battery drops back to 30-40mV after the lithium battery is fully charged according to practical test experience.
302. A voltage range for each charging phase is determined, as well as a charging current value.
Determining the cell voltage after (b-40 mV) -b being the last charging stage may be divided by n-1 segments equally for the range of a- (b-40 mV), resulting in a voltage width of c for each segment.
For example, a=4.3v, battery rated voltage b=4.45v, then N is equal to 4, i.e. divided into 5 charging phases, and the voltage span of each charging phase is ((4.45-0.04) -4.3V)/3≡0.04V from the 2 nd charging phase to the N-th charging phase.
The control logic may be:
A1 st charging stage, in which the charging current is 800mA when the battery voltage is below 4.3V;
a2 nd charging stage, namely 638mA for charging current when the battery voltage is 4.3-4.34V;
a 3 rd charging stage, namely 476mA for charging current when the battery voltage is 4.34-4.38;
a4 th charging stage, namely 314mA for charging current when the battery voltage is 4.38-4.41;
Stage 5 charging when the battery voltage is 4.41-4.45, the charging current is 150mA.
It should be noted that, the battery voltage value and the charging current value calculated by the above method may be adjusted according to the actual situation.
The actual measured data of the voltage control method and the data of the electric quantity control method are close to each other, so that the effect of improving the utilization rate of the battery can be achieved.
As shown in fig. 10, an embodiment of the present invention provides a charging chip, including:
The charging module 401 is configured to charge with different charging currents in N different charging phases, where N is an integer greater than or equal to 2 and is divided according to an electric quantity parameter of the battery;
The charging stage 1 is charged to a preset electric quantity parameter by a maximum charging current value allowed by the battery, the charging state is from the preset electric quantity parameter to the full charge state of the battery in the charging stage 2 to the charging stage N, the charging current value of each charging stage in the charging stage 2 to the charging stage N is gradually decreased, the charging current value of the last constant current charging stage is smaller than or equal to the preset current value, and the preset current value is determined according to the maximum allowed floating pressure and the internal resistance of the battery.
Optionally, the preset current value is determined according to a quotient of the allowed maximum float and the internal resistance of the battery.
The value of N is determined according to the internal resistance of the battery and the allowable maximum internal resistance.
Optionally, the charging current value of each charging phase is reduced by the same amount in the N charging phases.
Optionally, the decrease in the charging current value is obtained according to the following formula:
A=(Imax-IN)/(N-1);
Wherein, A represents a charging current value decreasing amount, Imax represents a maximum charging current value, IN represents a charging current value at an N-th stage, and N represents a total number of charging stages.
Optionally, the electrical parameter is an electrical percentage, or the electrical parameter is a voltage value.
The embodiment of the invention also provides terminal equipment, which comprises the charging chip.
The present invention provides a computer-readable storage medium storing a computer program, wherein the computer program causes a computer to execute some or all of the steps of the method as in the above method embodiments.
Embodiments of the present invention also provide a computer program product, wherein the computer program product, when run on a computer, causes the computer to perform some or all of the steps of the method as in the method embodiments above.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Those skilled in the art will also appreciate that the embodiments described in the specification are alternative embodiments and that the acts and modules referred to are not necessarily required for the present invention.
The terminal device provided by the embodiment of the present invention can implement each process shown in the foregoing method embodiment, and in order to avoid repetition, details are not repeated here.
In various embodiments of the present invention, it should be understood that the sequence numbers of the foregoing processes do not imply that the execution sequences of the processes should be determined by the functions and internal logic of the processes, and should not be construed as limiting the implementation of the embodiments of the present invention.
The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiment.
In addition, each functional unit in the embodiments of the present invention may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units described above, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer-accessible memory. Based on this understanding, the technical solution of the present invention, or a part contributing to the prior art or all or part of the technical solution, may be embodied in the form of a software product stored in a memory, comprising several requests for a computer device (which may be a personal computer, a server or a network device, etc., in particular may be a processor in a computer device) to execute some or all of the steps of the above-mentioned method of the various embodiments of the present invention.
Those of ordinary skill in the art will appreciate that all or part of the steps of the various methods of the above embodiments may be implemented by hardware associated with a program that may be stored in a computer-readable storage medium, including read-only memory (ROM), random-access memory (random access memory, RAM), programmable read-only memory (programmable read-only memory, PROM), erasable programmable read-only memory (erasable programmable read only memory, EPROM), one-time programmable read-only memory (OTPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (compact disc read-only memory, CD-ROM), or other optical disk storage, magnetic disk storage, tape storage, or any other medium that can be used for computer reading that carries or stores data.