CN103308865B - Method and electric equipment for calculating secondary battery SOC (system on a chip) and self-learning OCV (open circuit voltage)-SOC curve - Google Patents

Abstract

The invention provides a method of a self-learning OCV (open circuit voltage)-SOC (system on a chip) curve and a calculating method of secondary battery hopower state SOC value. With the calculating method, SOC value calculated through the calculating method can accurately display dump energy of batteries. Different from conditions that non real time and inaccuracy of battery internal resistor measurement in the existing technology lead to inaccuracy of self-learning OCV-SOC curve, the method of the self-learning OCV (open circuit voltage)-SOC(system on a chip) curve and the calculating method of secondary battery hopower state SOC value calculate internal resistor value r in a set time through measuring the most value of battery current and battery terminal voltage in a preset time in self-learning OCV-SOC curve so as to calculate open-circuit voltage during the preset time. Battery resistor can discharge with battery and time change are fully considered, so that battery internal resistor can be accurately traced during charging and discharging process of batteries, evenly-distributed OCV-SOC corresponding points can be acquired, and more accurate OCV-SOC curve can be acquired.

Description

The method of measuring and calculating secondary cell SOC and self study OCV-SOC curve and electronic equipment

Technical field

The present invention relates in electronic equipment the method and corresponding electronic equipment of calculating secondary cell electricity.

Background technology

The existing battery meter overwhelming majority is the detection adopting ampere-hour integral method to carry out battery electric quantity, and this method can not be knock-oned in whole charge and discharge process, adopts the AD of high bit number to carry out current sample and can obtain good precision.But ampere-hour integral method cannot detect for the leakage current produced after system closedown, after causing each start, cause cumulative errors because battery electric quantity initial value is inaccurate.Although this error can be revised by detecting open-circuit voltage corresponding battery electric quantity during start, the relation of this correspondence can change along with the change of the cycle life of battery, environment temperature etc.Existing certain methods is started with from detection battery temperature or cycle index, adopts different coefficients to compensate, but these class methods need to test thus calibration coefficient at each temperature and life-span battery in advance, and cannot solve the problem of individual cells difference; Although other methods can self-correcting OCV-SOC curve, often precision is poor.The technology of therefore current detection battery electric quantity need further improvement.

A kind of representation of OCV-SOC curve is such as shown in Fig. 1, its axis of ordinates is open-circuit voltage (OpenCircuit Voltage), abscissa axis is the state-of-charge SOC of battery, SOC is used to the residual capacity situation reflecting battery, and it is numerically defined as the ratio that battery remaining power accounts for battery capacity.

Summary of the invention

The object of the present invention is to provide a kind of method of self study secondary cell OCV-SOC curve, the OCV-SOC curve using the method to obtain can reflect the relation between open circuit voltage of secondary battery and state-of-charge exactly.In addition present invention also offers a kind of measuring method of secondary cell state-of-charge SOC value, the SOC value using the method to calculate can reflect the dump energy of battery exactly.In addition the present invention is based on and described method provide a kind of electronic equipment that can show dump energy exactly.

For realizing the present invention's first goal of the invention, the invention provides a kind of method of self study secondary cell OCV-SOC curve, the method, in the process of self study OCV-SOC curve, calculates the open-circuit voltage V of battery _ocvcomprise the following steps:

In battery discharge or charging process, gather battery current and the battery terminal voltage of battery according to the sampling rate preset, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period _outmax, V _outmaxwith minimum value: I _outmin, V _outmin, the internal resistance value r account form calculating secondary cell in this time period is as follows:

$r=\frac{V_{\mathrm{out}\max }-V_{\mathrm{out}\min }}{I_{\mathrm{out}\max }-I_{\mathrm{out}\min }}$ (formula 1)

The open-circuit voltage V of battery in this time period is calculated according to the internal resistance value r of battery in this time period _ocv, account form is as follows:

V _ocv=V _outmin+ I _outmaxr (formula 2a) or

V _ocv=V _outmax+ I _outminr (formula 2b).

Preferably, in the process of self study OCV-SOC curve, the state-of-charge SOC of measuring and calculating battery comprises the following steps:

Detect the terminal voltage of battery, the current i of battery, the open-circuit voltage V of measuring and calculating battery _ocv, as the V of battery _ocvvalue is from low spot V ₁start to be charged to high some V ₂, and at height point V ₂when switching charging and discharging state, according to the OCV-SOC curve measuring and calculating V prestored ₂corresponding SOC value b%, in conjunction with the battery electric quantity AH started when charging _a, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/b\%$ (formula 3a)

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor starting the time point charged, t _bfor the time point that charging and discharging state switches;

Battery discharge, calculates each V obtained in (formula 2a) or (formula 2b) _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=b\%-{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4a)

T in formula _cfor V in (formula 2a) or (formula 2b) _ocvtime point in the value corresponding time period, t _bfor the time point that charging and discharging state switches;

According to the SOC that (formula 4a) obtains _cand the V that (formula 2a) or (formula 2b) obtains _ocvmatching OCV-SOC curve.

More preferably, the condition activating self study OCV-SOC curve procedures comprises: AH _a/ FC _oldbe less than the self study lower limit x% of setting, and t _btime the SOC that obtains according to (formula 5) _bbe not less than the self study upper limit y% of setting, (formula 5) is specific as follows:

${\mathrm{SOC}}_b=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/{\mathrm{FC}}_{\mathrm{old}}$ (formula 5).

Especially preferably, the condition activating self study OCV-SOC curve procedures comprises: comprising time point t _bthe time period of presetting in the variable quantity of electric current exceed preset value.

Especially preferably, by formula AH _a=FC _old× a% calculates AH _avalue, wherein a% is the SOC value started when charging, and the mode obtaining a% numerical value is:

By calculating the OCV started when charging, then search default OCV-SOC curve to determine the SOC value a% of its correspondence,

Or directly obtain the SOC value a% of battery when shutting down the front shutdown stored last time.

Preferably, in the process of self study OCV-SOC curve, the state-of-charge SOC of measuring and calculating battery comprises the following steps:

Detect the terminal voltage of battery, the current i of battery, the open-circuit voltage V of measuring and calculating battery _ocv, as the V of battery _ocvvalue is from low spot V ₁start to be charged to electricity saturation point V _fulltime, according to the battery electric quantity AH started when charging _aand ampere-hour integration, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}={\mathrm{AH}}_a+{\∫}_{t_a}^{t_{\mathrm{full}}}\mathrm{idt}$ (formula 3b)

In formula, i is cell current value, t _afor starting the time point charged, t _fullfor battery is charged to the saturated time point of electricity;

Battery discharge, calculates each V obtained in (formula 2a) or (formula 2b) _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=100\%-{\∫}_{t_{\mathrm{full}}}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4b)

T in formula _cfor V in (formula 2a) or (formula 2b) _ocvtime point in the value corresponding time period;

According to the SOC that (formula 4b) obtains _cand the V that (formula 2a) or (formula 2b) obtains _ocvmatching OCV-SOC curve.

More preferably, the condition activating self study OCV-SOC curve procedures comprises: AH _abe less than the self study lower limit AH of setting _x.

Preferably, in the process of charging and discharge, according to the ampere-hour integration of the time interval measuring and calculating battery preset, and store.

Preferably, V is calculated respectively according to (formula 2a) and (formula 2b) _ocv, as two V that two algorithms calculate _ocvdifference when being greater than preset value, give up the V of this time period _ocv.

Preferably, in step: in battery discharge or charging process, gather battery current and the battery terminal voltage of battery according to the sampling rate preset, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period _outmax, V _outmaxwith minimum value: I _outmin, V _outminin, battery is discharge process, and the default time period is 0.1s ~ 10s.

Preferably, in step: in battery discharge or charging process, gather battery current and the battery terminal voltage of battery according to the sampling rate preset, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period _outmax, V _outmaxwith minimum value: I _outmin, V _outminin, I _outmax-I _outminor V _outmax-V _outminthe V of this time period is given up when being less than preset value _ocv.

Present invention also offers a kind of measuring method of secondary cell state-of-charge SOC value, comprise the following steps:

Start;

Detected apart from unused time last time;

Judge whether exceeded the default time apart from unused time last time, if exceeded the default time apart from unused time last time, detect battery open circuit voltage OCV value, and search OCV-SOC curve and determine SOC initial value, if be no more than the default time apart from unused time last time, SOC value when shutting down with last time is SOC initial value;

Start charging, when judging to charge, whether SOC value is lower than the setting self study lower limit set, if lower than the self study lower limit of setting, then activate self study OCV-SOC curve procedures, the method that described self study OCV-SOC curve procedures uses is the method for self study secondary cell OCV-SOC curve of the present invention;

Obtain new OCV-SOC curve, replace original OCV-SOC curve with the new OCV-SOC curve obtained;

Detect battery open circuit voltage V _ocvvalue, and the SOC value of searching that OCV-SOC curve determines now, and by the SOC value of ampere-hour integral method calculated for subsequent.

Present invention also offers a kind of electronic equipment, comprising the secondary cell for powering, timing module, voltage detection module, current detection module, memory module, display module, processor;

Wherein voltage detection module is for detecting battery terminal voltage, and current detection module is for detecting battery current, and memory module stores OCV-SOC curve, display module for showing SOC value,

Described processor is connected with timing module, voltage detection module, current detection module, memory module, display module, for matching OCV-SOC curve,

Described processor comprises open-circuit voltage measuring and calculating module, in battery discharge or charging process, gathers battery current and the battery terminal voltage of battery according to the sampling rate preset, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period _outmax, V _outmaxwith minimum value: I _outmin, V _outmin, the internal resistance value r account form calculating secondary cell in this time period is as follows:

$r=\frac{V_{\mathrm{out}\max }-V_{\mathrm{out}\min }}{I_{\mathrm{out}\max }-I_{\mathrm{out}\min }}$ (formula 1)

The open-circuit voltage V of battery in this time period is calculated according to the internal resistance value r of battery in this time period _ocv, account form is as follows:

V _ocv=V _outmin+ I _outmaxr (formula 2a) or

V _ocv=V _outmax+ I _outminr (formula 2b).

Preferably, described processor comprises state-of-charge measuring and calculating module, for according to the OCV of battery calculated and the current i of battery, calculates the state-of-charge of battery, as the V of battery _ocvvalue is from low spot V ₁start to be charged to high some V ₂, and at height point V ₂when switching charging and discharging state, according to the OCV-SOC curve measuring and calculating V prestored ₂corresponding SOC value b%, in conjunction with the battery electric quantity AH started when charging _a, work as AH _abe less than the self study lower limit AH of setting _x, and t _btime the SOC that obtains according to (formula 5) _bwhen being not less than the self study upper limit y% of setting, activating self study OCV-SOC curve procedures, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/b\%$ (formula 3a)

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor starting the time point charged, t _bfor the time point that charging and discharging state switches,

Wherein calculate SOC _bmethod specific as follows:

${\mathrm{SOC}}_b=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/{\mathrm{FC}}_{\mathrm{old}}$ (formula 5);

Battery discharge, calculates each V obtained in (formula 2a) or (formula 2b) _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=b\%-{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4a)

T in formula _cfor V in (formula 2a) or (formula 2b) _ocvtime point in the value corresponding time period, t _bfor battery is charged to the time point starting after height is put to discharge;

Processor is used for the SOC obtained according to (formula 4a) _cand the V that (formula 2a) or (formula 2b) obtains _ocvmatching OCV-SOC curve.

More preferably, described processor is used for when comprising time point t _bthe time period of presetting in the variable quantity of electric current exceed preset value, activate self study OCV-SOC curve procedures.

Preferably, described processor comprises state-of-charge measuring and calculating module, for according to the OCV of battery calculated and the current i of battery, calculates the state-of-charge of battery, as the V of battery _ocvvalue is from low spot V ₁start to be charged to electricity saturation point V _fulltime, calculate V according to the OCV-SOC curve prestored ₁corresponding SOC value a%, works as AH _alower than setting self study lower limit AH _xtime, activate self study OCV-SOC curve procedures, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}={\mathrm{AH}}_a+{\∫}_{t_a}^{t_{\mathrm{full}}}\mathrm{idt}$ (formula 3b)

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor starting the time point charged, t _fullfor battery is charged to the saturated time point of electricity;

Battery discharge, calculates each V obtained in (formula 2a) or (formula 2b) _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=100\%-{\∫}_{t_{\mathrm{full}}}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4b)

T in formula _cfor V in (formula 2a) or (formula 2b) _ocvtime point in the value corresponding time period;

Processor is used for the SOC obtained according to (formula 4b) _cand the V that (formula 2a) or (formula 2b) obtains _ocvmatching OCV-SOC curve.

Preferably, described processor is used for, when detecting apart from unused time last time after start;

Judge whether exceeded the default time apart from unused time last time, if exceeded the default time apart from unused time last time, detect battery open circuit voltage V _ocvvalue, and search OCV-SOC curve and determine SOC initial value, if be no more than the default time apart from unused time last time, SOC value when shutting down with last time is SOC initial value;

Start charging, when judging to charge, whether SOC value is lower than the setting self study lower limit set, if lower than the self study lower limit of setting, then activate self study OCV-SOC curve procedures, the method that described self study OCV-SOC curve procedures uses is the method for self study secondary cell OCV-SOC curve of the present invention;

Obtain new OCV-SOC curve, replace original OCV-SOC curve with the new OCV-SOC curve obtained;

Detect battery open circuit voltage OCV value, and search the SOC value that OCV-SOC curve determines now, and pass through the SOC value of ampere-hour integral method calculated for subsequent.

Be different from non real-time nature and inaccuracy that self study OCV-SOC curve in prior art is limited by internal resistance of cell detection, cause the situation of precision deficiency, the present invention passes through the battery current measuring battery in preset time period when self study OCV-SOC curve, the most value of battery terminal voltage, calculate the internal resistance value r in this time period, and then the open-circuit voltage extrapolated in this time period, owing to having taken into full account that internal resistance is with battery charging and discharging and time variations, therefore can the accurate tracking internal resistance of cell thus obtain equally distributed OCV-SOC corresponding point in whole battery charge and discharge process, OCV-SOC curve is more accurately obtained with this.

The measuring method of secondary cell state-of-charge SOC value of the present invention, owing to there is comparatively big error between the SOC value after SOC value when the leakage of battery electric quantity caused shut down last time after considering long-time shutdown and start, therefore the time between shutting down-starting shooting is judged after power-up, if the time interval wherein exceedes preset value, then do not adopt SOC value when shutting down last time, and determine SOC initial value by searching OCV-SOC curve, the SOC value obtained like this is more accurate.Simultaneously, when battery electric quantity is lower than preset value and when starting to charge, start OCV-SOC curve self study process, based on the method for the present invention above-mentioned self study OCV-SOC curve, obtain the inquiry of the new curve of OCV-SOC more accurately for SOC value, in conjunction with ampere-hour integral method, improve the accuracy of the SOC value obtained.

Electronic equipment of the present invention, by corresponding sensor and module, and connected mode, utilize the method for the invention, the accurate SOC value of secondary cell in electronic equipment can be obtained.

Accompanying drawing explanation

Fig. 1 is OCV-SOC curve map described in background technology of the present invention and embodiment;

Fig. 2 is the configuration diagram of electronic equipment described in the specific embodiment of the invention;

Fig. 3 is the measuring method process flow diagram of secondary cell state-of-charge SOC value described in the specific embodiment of the invention.

Embodiment

By describing technology contents of the present invention, structural attitude in detail, realized object and effect, accompanying drawing is coordinated to be explained in detail below in conjunction with embodiment.

In following content, each technical characteristic is described as follows:

OCV is open-circuit voltage (Open Circuit Voltage), and its numerical value is denoted as V in the present invention _ocvvalue, is also denoted as OCV value.

SOC is the state-of-charge of battery, and it is used to the residual capacity situation reflecting battery, and it is numerically defined as the ratio that battery remaining power accounts for battery capacity.

OCV-SOC look-up table and OCV-SOC curve are identical data or content, because intuitively observe, namely the data one_to_one corresponding in OCV-SOC look-up table are obtained OCV-SOC curve to functional picture.

Refer to Fig. 2, present embodiments provide an electronic equipment, this electronic equipment can be mobile phone, panel computer, PDA, notebook computer, digital camera, MP4, e-book or MP3 etc., described electronic equipment comprises the secondary cell for powering, timing module, voltage detection module 201, current detection module 202, memory module, display module 205, processor.

Wherein voltage detection module is for detecting battery terminal voltage, and current detection module is for detecting battery current, and memory module stores OCV-SOC curve, display module for showing SOC value,

Described processor is connected with timing module, voltage detection module 201, current detection module 202, memory module, display module 205, for matching OCV-SOC curve,

Described processor comprises open-circuit voltage measuring and calculating module, state-of-charge measuring and calculating module;

Open-circuit voltage measuring and calculating module comprises voltage and is worth detection sub-module 203 most, current best value detection sub-module 204, internal resistance calculating sub module 206, open-circuit voltage calculating sub module 207;

Current best value detection sub-module 204 is connected with current detection module 202, in battery discharge or charging process, gathers the battery current of battery according to the sampling rate preset, the maximal value of the battery current of battery: I in record preset time period _outmaxwith minimum value: I _outmin,

Voltage is worth detection sub-module 203 most and is connected with voltage detection module 201, for gathering the battery terminal voltage of battery according to the sampling rate preset, and the maximal value of battery terminal voltage: V in record preset time period _outmaxwith minimum value: V _outmin,

Internal resistance calculating sub module 206 is for calculating the internal resistance value r of secondary cell in this time period, and account form is as follows:

$r=\frac{V_{\mathrm{out}\max }-V_{\mathrm{out}\min }}{I_{\mathrm{out}\max }-I_{\mathrm{out}\min }}$ (formula 1)

Open-circuit voltage calculating sub module 207 is for calculating the open-circuit voltage V of battery in this time period according to the internal resistance value r of battery in this time period _ocv, account form is as follows:

V _ocv=V _outmin+ I _outmaxr (formula 2a) or

V _ocv=V _outmax+ I _outminr (formula 2b).

State-of-charge measuring and calculating module, for the OCV of battery and the current i of battery according to measuring and calculating, calculate the state-of-charge of battery, it comprises: coulombmeter 208, voltameter operator module 209.Coulombmeter 208 calculates for utilizing ampere-hour integral method the electricity passed through, and voltameter operator module 209 calculates battery electric quantity for the integral result in conjunction with coulombmeter 208.Specific as follows:

When the OCV value of battery is from low spot V ₁be charged to high some V ₂time, and at height point V ₂switch to discharge condition, calculate V according to the OCV-SOC curve prestored ₁corresponding SOC value a% and V ₂corresponding SOC value b%, when a% is lower than setting self study lower limit x%, activates self study OCV-SOC curve procedures, calculates new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}=({\mathrm{FC}}_{\mathrm{old}}\×a\%+{\∫}_{t_a}^{t_b}\mathrm{idt})/b\%$ (formula 3)

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value; t _afor starting the V that charges _ocvvalue low spot V ₁corresponding time point, t _bfor V _ocvthe high point of value and discharge and recharge switching point V ₂corresponding time point.

Battery discharge, calculates each V obtained in (formula 2a) or (formula 2b) _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c={\mathrm{SOC}}_b-{\∫}_{\mathrm{tb}}^{\mathrm{tc}}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4a)

In formula, tc is V in (formula 2a) or (formula 2b) _ocvtime point in the value corresponding time period, t _bfor battery is charged to the time point starting after height is put to discharge;

The SOC of processor also for obtaining according to (formula 4) _cand the V that (formula 2a) or (formula 2b) obtains _ocvmatching OCV-SOC curve, upgrades OCV-SOC look-up table by update module 210.

Preferably, processor comprises computing module 211 excess time, can maintain the time that equipment runs, and shown by display module 205 for calculating dump energy according to SOC and power consumption condition.

With reference to figure 3, in one embodiment of this invention, provide a kind of measuring method of secondary cell state-of-charge SOC value, comprise the following steps:

S301, work start;

S302 judges the unused time of battery, if be less than certain unused time, carries out

SOC value when step S303 shut down using last time, as the SOC initial value a% of current start, carries out step S305.

After detecting and being greater than certain unused time, carry out

Step S304 detects open-circuit voltage, and look into OCV-SOC table and decide SOC initial value a%, this value must be less than or equal to the SOC value of record when shutting down last time, the SOC value of record when shutting down last time is greater than as found, then belong to and detecting extremely, cast out this value, the SOC value still using shut down last time is as start initial value SOC _old, carry out step S305.

S305 judges whether battery meets OCV-SOC curve self study condition, if do not have activated batteries self study condition, carries out step S306 sample rate current and to go forward side by side line time integration.

Step S307 calculates real time electrical quantity according to ampere-hour integral method, and computing formula is:

${\mathrm{SOC}}_c=b\%\±{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4a)

Wherein, SOC _cmean current SOC value, add as charging in formula, be kept to electric discharge, FC is battery rated capacity, range of integration t _bwith t _crefer to respectively start the moment of integration and the moment of current calculated SOC.Specific to from the process being charged to electric discharge, in the process obtaining OCV-SOC curve, first calculate V _ocvnumerical value, and determine this V _ocvtime period (t corresponding to numerical value _cbe positioned at this time period), then calculate the SOC value SOC of this time _c, t _bfor the time point that charging and discharging state switches;

If meet battery self study condition, then enter battery OCV-SOC curve segmentation self study process.Self study process is as follows:

Carry out step S308 and correct battery current capacities: the specified electric quantity FC prestoring a typical battery OCV-SOC homologous thread and battery in voltameter.And under equipment charge and discharge condition, equipment measures battery current according to the time period of presetting, and carries out ampere-hour integration.

As shown in Figure 1, SOC is worked as _avalue a% gets after 20% lower than x% in self study lower limit x%(the present embodiment), be charged to the SOC that dump energy and ampere-hour integration sum obtain _b80% is got higher than y% in self study upper limit y%(the present embodiment), and when starting to discharge, activate OCV-SOC curve self-learning function (activation condition is not limited to from 20% to 80%, also can be set as the arbitrary value of 10% to 90% or other points from low spot to height).Now calculate new battery specified electric quantity value:

${\mathrm{FC}}_{\mathrm{new}}=({\mathrm{FC}}_{\mathrm{old}}\×a\%+{\∫}_{t_a}^{t_b}\mathrm{idt})/b\%$ (formula 3a)

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor starting the V that charges _ocvvalue low spot V ₁corresponding time point, t _bfor V _ocvthe high point of value and discharge and recharge switching point V ₂corresponding time point.

Due to t _bfor discharge and recharge switching point, therefore battery current has larger change therebetween, can obtain OCV value comparatively accurately.T _afor starting the time point that charging starts, also easily record OCV value accurately therebetween.

Determining V ₂time SOC _bwhether prescribe a time limit higher than in the self study of setting, the SOC of employing _balgorithm is as follows:

${\mathrm{SOC}}_b=({\mathrm{FC}}_{\mathrm{old}}\×a\%+{\∫}_{t_a}^{t_b}\mathrm{idt})/{\mathrm{FC}}_{\mathrm{old}}$ (formula 5)

In the formula of some embodiment, SOC value a%, by calculating the OCV value obtained, searches the OCV-SOC curve table prestored and obtains, the SOC value a% of battery during the shutdown stored before also directly can continuing to use shutdown last time.

In certain embodiments, in order to more accurately obtain the specified electric quantity value of battery, except requiring discharge and recharge switching point V ₂sOC during corresponding time point _boutside self study upper limit y% higher than setting, the variable quantity also setting b% switching point electric current exceedes preset value, and such as, under the common battery capacity of panel computer, this default settings is 200mA.Because battery transfers electric discharge to from charging, electric current generally has large change, can be recorded corresponding open-circuit voltage values V at b% point by the method that the present invention is above-mentioned _{ocv_b}, then again by searching default OCV-SOC table, obtain this stylish SOC value (b% namely in formula 3a), the electricity of the b% point then using this value and ampere-hour integration before to obtain is to upgrade new battery rated capacity.

Thus, in the above-described embodiments, whether the height point of charging meets activation self study process is calculated by ampere-hour integration, and when recalculating the rated capacity of battery, the electricity of the high point of charging is the open-circuit voltage by calculating this point, and then searches that default OCV-SOC table obtains.

In some embodiment, activate in the condition of OCV-SOC curve self-learning function, set charging upper limit saturated as charging, after battery is full of, signal full that a battery is full of is provided to voltameter by charging management chip, battery electric quantity is now 100%, and namely the end value of ampere-hour integration is the rated capacity that battery is new.

${\mathrm{FC}}_{\mathrm{new}}={\mathrm{FC}}_{\mathrm{old}}\×a\%+{\∫}_{\mathrm{ta}}^{\mathrm{tfull}}\mathrm{idt}$ (formula 3b)

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor the time point that the SOC value that starts to charge is a%, t _fullfor battery is charged to the saturated time point of electricity;

In an embodiment of the present invention, by calculating the OCV started when charging, then searching default OCV-SOC curve to determine the SOC value a% of its correspondence, then using FC _old× a% is as the battery electric quantity AH started when charging _abe a kind of mode, other mode is when the unused time is less than Preset Time, directly can utilize the SOC value a% of the battery before shutdown last time and be used as the battery electric quantity AH started when charging _athe use of calculating.

Adopt this method, because the electricity saturated electricity that charges is clear and definite, namely 100%, therefore need to search default OCV-SOC curve to determine the algorithm of an electricity height point value relative in embodiment before in formula, lacked a source of error, its result is more accurate.

In some embodiment, electricity when charging can be set and, lower than the self study lower limit preset, namely start self study process.Certainly, when setting is charged simultaneously in the present embodiment, electricity is lower than the self study lower limit preset, and the electricity after charging is higher than the self study upper limit preset, can ensure that before and after charging, the electricity of battery has larger change like this, the Data distribution8 obtained for matching OCV-SOC curve is wider, contributes to the accuracy improving the OCV-SOC curve obtained.

S309 internal resistance calculates tracking in real time: after battery discharges from b%, with certain sampling rate sampling battery electric current and cell voltage, the most value of battery current and battery terminal voltage in record a period of time, because internal resistance and open-circuit voltage remain unchanged in certain hour section, following system of equations can be obtained:

V _ocv=V _outmin+ I _outmaxr (formula 2a) or

V _ocv=V _outmax+ I _outminr (formula 2b)

Solve: $r=\frac{\mathrm{\Δ}{V}_{\mathrm{out}}}{\mathrm{\Δ}{I}_{\mathrm{out}}}=\frac{V_{\mathrm{out}\max }-V_{\mathrm{out}\min }}{I_{\mathrm{out}\max }-I_{\mathrm{out}\min }}$ (formula 1)

In order to make division more accurate, Δ V be made _outwith Δ I _outlarge as far as possible, so need to carry out computing by the extreme value of cell voltage in certain hour and battery current.Therefore in a preferred embodiment, if I _outmax/ I _outminor V _outmax/ V _outminthe V of this time period is given up when being less than preset value _ocv.

In a preferred embodiment, carry out internal resistance to calculate tracking effect in real time better when battery discharge because when charging, battery current and terminal voltage relatively stable, Δ V _outwith Δ I _outrelatively little, when discharging, due to the change of equipment running load, there is larger fluctuation in battery current, and terminal voltage also produces larger fluctuation, Δ V _outwith Δ I _outlarger.Through experiment, measuring and calculating battery current and time period of being worth most of terminal voltage are that 0.1s to 10s is better, because lower than 0.1s, the change of load is not obvious, battery current and voltage undulation little; Be greater than 10s, internal resistance and the open-circuit voltage of battery likely change, thus cause the result accuracy obtained to be affected.

Experiment simultaneously shows, when battery electric quantity change is more than 1%, the change of the internal resistance of cell and open-circuit voltage can affect the result of measuring and calculating comparatively significantly.

S310:OCV real-time follow-up.

The real-time internal resistance of cell value solved is taken back in equation, calculates real-time battery open circuit voltage values

V _ocv=V _outmin+ I _outmaxr or V _ocv=V _outmax+ I _outminr

Both are generally equal or comparatively close, also can get the mean value of twice calculating as last open-circuit voltage values.In some preferred embodiment, the V obtained with above two formulae discovery _ocvthere is larger difference, then think that the confidence level of respective value leaves a question open, given up.

S311:SOC real-time follow-up.

The SOC value that synchronous calculating each OCV point is corresponding when upgrading, the result utilizing step S306 integration to obtain in the process calculated, computing formula is as follows:

${\mathrm{SOC}}_c=b\%-{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4a)

Be full of according to battery, method described in the embodiment of activation OCV-SOC curvature correction process, above-mentioned computing method are rewritten as:

${\mathrm{SOC}}_c=100\%-{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ (formula 4b)

T in formula _bfor the time point that charging and discharging state switches; When obtaining OCV-SOC curve, measuring and calculating V _ocvnumerical value, and determine this V _ocvtime period (t corresponding to numerical value _cbe positioned at this time period), calculate the SOC value SOC of this time _c.

In certain embodiments, according to the ampere-hour integration of the time interval measuring and calculating battery preset, and storing, like this when condition meets, after activating OCV-SOC curvature correction process, conveniently can calling the ampere-hour integration data of storage for calculating.Certainly in other embodiments, also can direct storaging current-time data, carry out integration again when needing.

S312: correct OCV-SOC curve, when battery discharge terminates and start to charge, upgrades OCV-SOC look-up table with each OCV-SOC respective value segmentation calculated.

After OCV-SOC look-up table upgrades, re-start step S304, detect open-circuit voltage, look into OCV-SOC table and decide SOC initial value, certainly the new OCV-SOC table of OCV-SOC table for obtaining after self study now, its comparatively upgrade before OCV-SOC table more can reflect the relation of current battery OCV and SOC exactly.

S313 shuts down.

In certain embodiments, the OCV-SOC curve self-learning method used in above-described embodiment can be used alone, and is applied to the occasion needing self study OCV-SOC curve.

In certain embodiments, also can directly according to the OCV-SOC curve direct measuring SOC value obtained after self study.

The foregoing is only embodiments of the invention; not thereby the scope of the claims of the present invention is limited; every utilize instructions of the present invention and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present invention.

Claims (15)

1. a method for self study secondary cell OCV-SOC curve, is characterized in that, in the process of self study OCV-SOC curve, and the open-circuit voltage V of measuring and calculating battery _ocvcomprise the following steps:

In battery discharge or charging process, gather battery current and the battery terminal voltage of battery according to the sampling rate preset, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period _outmax, V _outmaxwith minimum value: I _outmin, V _outmin, the internal resistance value r account form calculating secondary cell in this time period is as follows:

$r=\frac{V_{\mathrm{out}\max }-V_{\mathrm{out}\min }}{I_{\mathrm{out}\max }-I_{\mathrm{out}\min }}$ Formula 1

The open-circuit voltage V of battery in this time period is calculated according to the internal resistance value r of battery in this time period _ocv, account form is as follows:

V _ocv=V _outmin+ I _outmaxr formula 2a or

V _ocv=V _outmax+ I _outminr formula 2b

In the process of self study OCV-SOC curve, the state-of-charge SOC of measuring and calculating battery comprises the following steps:

Detect the terminal voltage of battery, the current i of battery, the open-circuit voltage V of measuring and calculating battery _ocv, as the V of battery _ocvvalue is from low spot V ₁start to be charged to high some V ₂, and at height point V ₂when switching charging and discharging state, according to the OCV-SOC curve measuring and calculating V prestored ₂corresponding SOC value b%, in conjunction with the battery electric quantity AH started when charging _a, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/b\%$ Formula 3a

In formula, i is cell current value, t _afor starting the time point charged, t _bfor the time point that charging and discharging state switches;

Battery discharge, each V obtained in calculating formula 2a or formula 2b _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=b\%-{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ Formula 4a

T in formula _cfor V in formula 2a or formula 2b _ocvtime point in the value corresponding time period, t _bfor the time point that charging and discharging state switches;

According to the SOC that formula 4a obtains _cand the V that formula 2a or formula 2b obtains _ocvmatching OCV-SOC curve.

2. the method for self study secondary cell OCV-SOC curve according to claim 1, is characterized in that, the condition activating self study OCV-SOC curve procedures comprises: AH _a/ FC _oldbe less than the self study lower limit x% of setting, and t _btime the SOC that obtains according to formula 5 _bbe not less than the self study upper limit y% of setting, formula 5 is specific as follows:

${\mathrm{SOC}}_b=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/{\mathrm{FC}}_{\mathrm{old}}$ Formula 5

FC _oldfor the battery specified electric quantity value prestored.

3. the method for self study secondary cell OCV-SOC curve according to claim 2, is characterized in that, by formula AH _a=FC _old× a% calculates AH _avalue, wherein a% is the SOC value started when charging, and the mode obtaining a% numerical value is:

By calculating the OCV started when charging, then search default OCV-SOC curve to determine the SOC value a% of its correspondence,

Or directly obtain the SOC value a% of battery when shutting down the front shutdown stored last time.

4. the method for self study secondary cell OCV-SOC curve according to claim 2, is characterized in that, the condition activating self study OCV-SOC curve procedures comprises: comprising time point t _bthe time period of presetting in the variable quantity of electric current exceed preset value.

5. the method for self study secondary cell OCV-SOC curve according to claim 1, is characterized in that, in the process of self study OCV-SOC curve, the state-of-charge SOC of measuring and calculating battery comprises the following steps:

Detect the terminal voltage of battery, the current i of battery, the open-circuit voltage V of measuring and calculating battery _ocv, as the V of battery _ocvvalue is from low spot V ₁start to be charged to electricity saturation point V _fulltime, according to the battery electric quantity AH started when charging _aand ampere-hour integration, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}={\mathrm{AH}}_a+{\∫}_{t_a}^{t_{\mathrm{full}}}\mathrm{idt}$ Formula 3b

In formula, i is cell current value, t _afor starting the time point charged, t _fullfor battery is charged to the saturated time point of electricity;

Battery discharge, each V obtained in calculating formula 2a or formula 2b _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=100\%-{\∫}_{t_{\mathrm{full}}}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ Formula 4b

T in formula _cfor V in formula 2a or formula 2b _ocvtime point in the value corresponding time period;

According to the SOC that formula 4b obtains _cand the V that formula 2a or formula 2b obtains _ocvmatching OCV-SOC curve.

6. the method for self study secondary cell OCV-SOC curve according to claim 5, is characterized in that, the condition activating self study OCV-SOC curve procedures comprises: AH _abe less than the self study lower limit AH of setting _x.

7. the method for the self study secondary cell OCV-SOC curve according to claim 1 to 6 any one, is characterized in that, in the process of charging and discharge, according to the ampere-hour integration of the time interval measuring and calculating battery preset, and stores.

8. the method for self study secondary cell OCV-SOC curve according to claim 1, is characterized in that, calculate V respectively according to formula 2a and formula 2b _ocv, as two V that two algorithms calculate _ocvdifference when being greater than preset value, give up the V of this time period _ocv.

9. the method for self study secondary cell OCV-SOC curve according to claim 1, it is characterized in that, in step: in battery discharge or charging process, battery current and the battery terminal voltage of battery is gathered, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period according to the sampling rate preset _outmax, V _outmaxwith minimum value: I _outmin, V _outminin, battery is discharge process, and the default time period is 0.1s ~ 10s.

10. the method for self study secondary cell OCV-SOC curve according to claim 1, it is characterized in that, in step: in battery discharge or charging process, battery current and the battery terminal voltage of battery is gathered, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period according to the sampling rate preset _outmax, V _outmaxwith minimum value: I _outmin, V _outminin, I _outmax-I _outminor V _outmax-V _outminthe V of this time period is given up when being less than preset value _ocv.

The measuring method of 11. 1 kinds of secondary cell state-of-charge SOC value, is characterized in that, comprise the following steps:

Start;

Detected apart from unused time last time;

Judge whether exceeded the default time apart from unused time last time, if exceeded the default time apart from unused time last time, detect battery open circuit voltage OCV value, and search OCV-SOC curve and determine SOC initial value, if be no more than the default time apart from unused time last time, SOC value when shutting down with last time is SOC initial value;

Start charging, when judging to charge, whether SOC value is lower than the setting self study lower limit set, if lower than the self study lower limit of setting, then activate self study OCV-SOC curve procedures, the method that described self study OCV-SOC curve procedures uses is the method for self study secondary cell OCV-SOC curve described in claim 1 to 10 any one;

Obtain new OCV-SOC curve, replace original OCV-SOC curve with the new OCV-SOC curve obtained;

Detect battery open circuit voltage V _ocvvalue, and the SOC value of searching that OCV-SOC curve determines now, and by the SOC value of ampere-hour integral method calculated for subsequent.

12. 1 kinds of electronic equipments, is characterized in that, comprise the secondary cell for powering, timing module, voltage detection module, current detection module, memory module, display module, processor;

Wherein voltage detection module is for detecting battery terminal voltage, and current detection module is for detecting battery current, and memory module stores OCV-SOC curve, display module for showing SOC value,

Described processor is connected with timing module, voltage detection module, current detection module, memory module, display module, for matching OCV-SOC curve,

Described processor comprises open-circuit voltage measuring and calculating module, in battery discharge or charging process, gathers battery current and the battery terminal voltage of battery according to the sampling rate preset, the battery current of battery, the maximal value of battery terminal voltage: I in record preset time period _outmax, V _outmaxwith minimum value: I _outmin, V _outmin, the internal resistance value r account form calculating secondary cell in this time period is as follows:

$r=\frac{V_{\mathrm{out}\max }-V_{\mathrm{out}\min }}{I_{\mathrm{out}\max }-I_{\mathrm{out}\min }}$ Formula 1

The open-circuit voltage V of battery in this time period is calculated according to the internal resistance value r of battery in this time period _ocv, account form is as follows:

V _ocv=V _outmin+ I _outmaxr formula 2a or

V _ocv=V _outmax+ I _outminr formula 2b

Described processor comprises state-of-charge measuring and calculating module, for according to the OCV of battery calculated and the current i of battery, calculates the state-of-charge of battery, as the V of battery _ocvvalue is from low spot V ₁start to be charged to high some V ₂, and at height point V ₂when switching charging and discharging state, according to the OCV-SOC curve measuring and calculating V prestored ₂corresponding SOC value b%, in conjunction with the battery electric quantity AH started when charging _a, work as AH _abe less than the self study lower limit AH of setting _x, and t _btime the SOC that obtains according to formula 5 _bwhen being not less than the self study upper limit y% of setting, activating self study OCV-SOC curve procedures, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/b\%$ Formula 3a

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor starting the time point charged, t _bfor the time point that charging and discharging state switches,

Wherein calculate SOC _bmethod specific as follows:

${\mathrm{SOC}}_b=({\mathrm{AH}}_a+{\∫}_{t_a}^{t_b}\mathrm{idt})/{\mathrm{FC}}_{\mathrm{old}}$ Formula 5;

Battery discharge, each V obtained in calculating formula 2a or formula 2b _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=b\%-{\∫}_{t_b}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ Formula 4a

T in formula _cfor V in formula 2a or formula 2b _ocvtime point in the value corresponding time period, t _bfor battery is charged to the time point starting after height is put to discharge;

Processor is used for the SOC obtained according to formula 4a _cand the V that formula 2a or formula 2b obtains _ocvmatching OCV-SOC curve.

13. electronic equipments according to claim 12, is characterized in that, described processor is used for when comprising time point t _bthe time period of presetting in the variable quantity of electric current exceed preset value, activate self study OCV-SOC curve procedures.

14. electronic equipments according to claim 12, is characterized in that, described processor comprises state-of-charge measuring and calculating module, for according to the OCV of battery calculated and the current i of battery, calculates the state-of-charge of battery, as the V of battery _ocvvalue is from low spot V ₁start to be charged to electricity saturation point V _fulltime, calculate V according to the OCV-SOC curve prestored ₁corresponding SOC value a%, works as AH _alower than setting self study lower limit AH _xtime, activate self study OCV-SOC curve procedures, calculate new battery specified electric quantity value FC in the following manner _new:

${\mathrm{FC}}_{\mathrm{new}}={\mathrm{AH}}_a+{\∫}_{t_a}^{t_{\mathrm{full}}}\mathrm{idt}$ Formula 3b

In formula, FC _oldfor the battery specified electric quantity value prestored, i is cell current value, t _afor starting the time point charged, t _fullfor battery is charged to the saturated time point of electricity;

Battery discharge, each V obtained in calculating formula 2a or formula 2b _ocvsOC corresponding to value _c, account form is as follows:

${\mathrm{SOC}}_c=100\%-{\∫}_{t_{\mathrm{full}}}^{t_c}\mathrm{idt}/{\mathrm{FC}}_{\mathrm{new}}$ Formula 4b

T in formula _cfor V in formula 2a or formula 2b _ocvtime point in the value corresponding time period;

Processor is used for the SOC obtained according to formula 4b _cand the V that formula 2a or formula 2b obtains _ocvmatching OCV-SOC curve.

15., according to claim 12 to the electronic equipment described in 14 any one, is characterized in that, described processor is used for, when detecting apart from unused time last time after start;

Judge whether exceeded the default time apart from unused time last time, if exceeded the default time apart from unused time last time, detect battery open circuit voltage V _ocvvalue, and search OCV-SOC curve and determine SOC initial value, if be no more than the default time apart from unused time last time, SOC value when shutting down with last time is SOC initial value;

Start charging, when judging to charge, whether SOC value is lower than the setting self study lower limit set, if lower than the self study lower limit of setting, then activate self study OCV-SOC curve procedures, the method that described self study OCV-SOC curve procedures uses is the method for self study secondary cell OCV-SOC curve described in claim 1 to 6 any one;

Obtain new OCV-SOC curve, replace original OCV-SOC curve with the new OCV-SOC curve obtained;

Detect battery open circuit voltage OCV value, and search the SOC value that OCV-SOC curve determines now, and pass through the SOC value of ampere-hour integral method calculated for subsequent.