CN103308865A - 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

Method and the electronic equipment of measuring and calculating secondary cell SOC and self study OCV-SOC curve

Technical field

The present invention relates to method and the corresponding electronic equipment of measuring and calculating secondary cell electric weight in the electronic equipment.

Background technology

The existing battery electric quantity meter overwhelming majority adopts the ampere-hour integral method to carry out the detection of battery electric quantity, and this method can not knock-oned in whole charge and discharge process, and the AD of employing high bit number carries out current sample and can obtain good precision.But the leakage current that the ampere-hour integral method produces after for system closedown can't detect, and causes after each start because the inaccurate cumulative errors that cause of battery electric quantity initial value.Although this error can detect the corresponding battery electric quantity of open-circuit voltage by when start and revise, the relation of this correspondence can change along with the variation of the cycle life of battery, environment temperature etc.Existing certain methods is started with from detecting battery temperature or cycle index, adopts different coefficients to compensate, thereby but these class methods needs in advance to battery in each temperature with test calibration coefficient under the life-span, and can't solve the problem of battery individual difference; Although other methods can self-correcting OCV-SOC curve, often precision is relatively poor.Therefore the technology of present detection battery electric quantity is still waiting further improvement.

A kind of expression mode of OCV-SOC curve is for example shown in Figure 1, its axis of ordinates is open-circuit voltage (Open Circuit Voltage), abscissa axis is the state-of-charge SOC of battery, SOC is used to reflect the residual capacity situation of battery, is defined as the ratio that battery remaining power accounts for battery capacity on its numerical value.

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 that uses the method to obtain can reflect the relation between secondary cell open-circuit voltage and the state-of-charge exactly.The present invention also provides a kind of measuring method of secondary cell state-of-charge SOC value in addition, and the SOC value of using the method to calculate can reflect the dump energy of battery exactly.The present invention is based in addition said method a kind of electronic equipment that can show exactly dump energy is provided.

For realizing first goal of the invention of the present invention, the invention provides a kind of method of self study secondary cell OCV-SOC curve, the method is calculated the open-circuit voltage V of battery in the process of self study OCV-SOC curve _OcvMay further comprise the steps:

In battery discharge or charging process, gather battery current and the battery terminal voltage of battery according to default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _Outmin, the internal resistance value r account form of 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)

Calculate 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).

Preferably, in the process of self study OCV-SOC curve, the state-of-charge SOC of measuring and calculating battery may further comprise the 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 ₁Begin 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 that prestores ₂Corresponding SOC value b%, the battery electric quantity AH when beginning to charge _a, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aBe the time point that begins to charge, t _BTime point for the charging and discharging state switching;

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _c, account form is as follows:

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

T in the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute, t _bTime point for the charging and discharging state switching;

The SOC that obtains according to (formula 4a) _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

More preferably, the condition of activation self study OCV-SOC curve process comprises: AH _a/ FC _OldLess than the self study lower limit x% that sets, and t _bThe time 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 of activation self study OCV-SOC curve process comprises: comprising time point t _bThe default time period in the variable quantity of electric current surpass preset value.

Especially preferably, by formula AH _a=FC _Old* a% calculates AH _aValue, wherein a% is the SOC value when beginning to charge, the mode of obtaining a% numerical value is:

Then OCV when beginning to charge by calculating searches default OCV-SOC curve with definite its corresponding SOC value a%,

Or the SOC value a% of battery when directly obtaining the shutdown of storage before the last time shutdown.

Preferably, in the process of self study OCV-SOC curve, the state-of-charge SOC of measuring and calculating battery may further comprise the 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 ₁Begin to be charged to electric weight saturation point V _FullThe time, the battery electric quantity AH when beginning to charge _aAnd the ampere-hour integration, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, i is the battery current value, t _aBe the time point that begins to charge, t _FullFor battery is charged to the saturated time point of electric weight;

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _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 the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute;

The SOC that obtains according to (formula 4b) _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

More preferably, the condition of activation self study OCV-SOC curve process comprises: AH _aLess than the self study lower limit AH that sets _x

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

Preferably, calculate respectively V according to (formula 2a) and (formula 2b) _Ocv, two V that calculate when two algorithms _OcvDifference during 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 default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _OutminIn, battery is discharge process, 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 default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _OutminIn, I _Outmax-I _OutminOr V _Outmax-V _OutminThe V that gives up this time period during less than preset value _Ocv

The present invention also provides a kind of measuring method of secondary cell state-of-charge SOC value, may further comprise the steps:

Start;

Detection was apart from unused time last time;

Whether judgement surpasses the default time apart from unused time last time, if surpassed the time of presetting apart from unused time last time, detect battery open circuit voltage OCV value, and search the OCV-SOC curve and determine the SOC initial value, if be no more than the default time apart from unused time last time, the SOC value when shutting down take last time is the SOC initial value;

Begin charging, whether the SOC value is lower than the setting self study lower limit of setting when judging charging, if be lower than the self study lower limit of setting, then activate self study OCV-SOC curve process, the employed method of described self study OCV-SOC curve process 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 that obtains;

Detect battery open circuit voltage V _OcvValue, and search the SOC value that the OCV-SOC curve is determined this moment, and pass through the SOC value of ampere-hour integral method calculated for subsequent.

The present invention also provides a kind of electronic equipment, comprises the secondary cell for power supply, timing module, voltage detection module, current detection module, memory module, display module, processor;

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

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

Described processor comprises open-circuit voltage measuring and calculating module, is used in battery discharge or charging process, gathers battery current and the battery terminal voltage of battery according to default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _Outmin, the internal resistance value r account form of 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)

Calculate 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).

Preferably, described processor comprises state-of-charge measuring and calculating module, is used for according to the OCV of the battery of calculating and the current i of battery, and the state-of-charge of measuring and calculating battery is as the V of battery _OcvValue is from low spot V ₁Begin 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 that prestores ₂Corresponding SOC value b%, the battery electric quantity AH when beginning to charge _a, work as AH _aLess than the self study lower limit AH that sets _x, and t _bThe time SOC that obtains according to (formula 5) _bWhen being not less than the self study upper limit y% of setting, activate self study OCV-SOC curve process, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aBe the time point that begins to charge, t _BBe the time point of charging and discharging state switching,

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 that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _c, account form is as follows:

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

T in the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute, t _bBe charged to the time point that begins to discharge behind the high point for battery;

Processor is used for the SOC that basis (formula 4a) obtains _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

More preferably, described processor is used for when comprising time point t _bThe default time period in the variable quantity of electric current surpass preset value, activate self study OCV-SOC curve process.

Preferably, described processor comprises state-of-charge measuring and calculating module, is used for according to the OCV of the battery of calculating and the current i of battery, and the state-of-charge of measuring and calculating battery is as the V of battery _OcvValue is from low spot V ₁Begin to be charged to electric weight saturation point V _FullThe time, according to the OCV-SOC curve calculation V that prestores ₁Corresponding SOC value a% works as AH _aBe lower than and set self study lower limit AH _xThe time, activate self study OCV-SOC curve process, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aBe the time point that begins to charge, t _FullFor battery is charged to the saturated time point of electric weight;

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _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 the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute;

Processor is used for the SOC that basis (formula 4b) obtains _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

Preferably, described processor is used for, and detects apart from unused time last time after start;

Whether judgement surpasses the default time apart from unused time last time, if surpass the default time apart from unused time last time, detects battery open circuit voltage V _OcvValue and is searched the OCV-SOC curve and is determined the SOC initial value, if be no more than the default time apart from unused time last time, the SOC value when shutting down take last time is the SOC initial value;

Begin charging, whether the SOC value is lower than the setting self study lower limit of setting when judging charging, if be lower than the self study lower limit of setting, then activate self study OCV-SOC curve process, the employed method of described self study OCV-SOC curve process 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 that obtains;

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

Be different from self study OCV-SOC curve in the prior art and be limited by non real-time property and the inaccuracy that the internal resistance of cell detects, the situation that causes the precision deficiency, the present invention passes through to measure the battery current of battery in the Preset Time section when self study OCV-SOC curve, the value of battery terminal voltage, calculate the internal resistance value r in this time period, and then extrapolate open-circuit voltage in this time period, because having taken into full account internal resistance changed with battery charging and discharging and time, thereby therefore in whole battery charge and discharge process, can obtain equally distributed OCV-SOC corresponding point by the accurate tracking internal resistance of cell, obtain more accurately OCV-SOC curve with this.

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

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

Description of drawings

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

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

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

Embodiment

By describing technology contents of the present invention, structural attitude in detail, being realized purpose and effect, below in conjunction with embodiment and cooperate accompanying drawing to give in detail explanation.

In the following content, each technical characterictic 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 also is denoted as the OCV value.

SOC is the state-of-charge of battery, and the residual capacity situation that it is used to reflect battery is defined as the ratio that battery remaining power accounts for battery capacity on its numerical value.

OCV-SOC look-up table and OCV-SOC curve are identical data or content, because namely obtain the OCV-SOC curve on the functional picture from observing intuitively the data the OCV-SOC look-up table are corresponded to one by one.

See also Fig. 2, the present embodiment provides 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 power supply, timing module, voltage detection module 201, current detection module 202, memory module, display module 205, processor.

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

Described processor is connected with timing module, voltage detection module 201, current detection module 202, memory module, display module 205, is used for match 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 that voltage 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, is used in battery discharge or charging process, gathers the battery current of battery according to default sampling rate, the maximal value of the battery current of battery: I in the record Preset Time section _OutmaxWith minimum value: I _Outmin,

Voltage is worth detection sub-module 203 most and is connected with voltage detection module 201, is used for gathering according to default sampling rate the battery terminal voltage of battery, the maximal value of battery terminal voltage: V in the record Preset Time section _OutmaxWith minimum value: V _Outmin,

Internal resistance calculating sub module 206 is used 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 used for calculating according to the internal resistance value r of battery in this time period the open-circuit voltage V 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 is used for according to the OCV of the battery of calculating and the current i of battery, the state-of-charge of measuring and calculating battery, and it comprises: coulombmeter 208, voltameter operator module 209.Coulombmeter 208 is used for utilizing the ampere-hour integral method to calculate the electric weight that passes through, and voltameter operator module 209 is used for calculating battery electric quantity in conjunction with the integral result of coulombmeter 208.Specific as follows:

When the OCV of battery value from low spot V ₁Be charged to high some V ₂The time, and at height point V ₂Switch to discharge condition, according to the OCV-SOC curve calculation V that prestores ₁Corresponding SOC value a% and V ₂Corresponding SOC value b% sets self study lower limit x% when a% is lower than, and activates self study OCV-SOC curve process, calculates in the following manner new battery specified electric quantity value FC _New:

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value; t _aFor beginning the V that charges _OcvValue low spot V ₁Corresponding time point, t _BBe V _OcvSwitching point V is put and discharged and recharged to the value height ₂Corresponding time point.

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _c, account form is as follows:

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

Tc is V in (formula 2a) or (formula 2b) in the formula _OcvThe corresponding interior time point of time period of value institute, t _bBe charged to the time point that begins to discharge behind the high point for battery;

Processor also is used for the SOC that basis (formula 4) obtains _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve upgrades the OCV-SOC look-up table by update module 210.

As preferred version, processor comprises computing module 211 excess time, is used for calculating the time that dump energy can be kept the equipment operation according to SOC and power consumption situation, and shows by display module 205.

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, may further comprise the steps:

S301, the work start;

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

SOC value when step S303 shut down with last time is carried out step S305 as the SOC initial value a% of current start.

After detecting greater than certain unused time, carry out

Step S304 detects open-circuit voltage, looks into the OCV-SOC table and decides SOC initial value a%, the SOC value of record when this value must be shut down less than or equal to last time, the SOC value of record when shutting down greater than last time such as discovery, then belong to and detecting unusually, cast out this value, still use the SOC value of shutdown last time as start initial value SOC _Old, carry out step S305.

S305 judges whether battery satisfies OCV-SOC curve self study condition, if there is not activated batteries self study condition, carries out the step S306 sample rate current line time integration of going forward side by side.

Step S307 calculates real-time electric weight according to the 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 the formula, be kept to discharge, FC is the battery rated capacity, range of integration t _bWith t _cRefer to respectively begin the moment of integration and the moment of the present SOC that calculates.Specific to from being charged to the process of discharge, in the process that obtains the OCV-SOC curve, calculate first V _OcvNumerical value, and determine this V _OcvCorresponding time period (the t of numerical value institute _cBe positioned at this time period), then calculate the SOC value SOC of this time _c, t _bTime point for the charging and discharging state switching;

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

Carry out step S308 and proofread and correct the current capacity of battery: the specified electric quantity FC of the corresponding curve of a pre-stored typical battery OCV-SOC and battery in the voltameter.And under equipment charge and discharge condition, equipment is measured battery current according to the default time period, carries out the ampere-hour integration.

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

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aFor beginning the V that charges _OcvValue low spot V ₁Corresponding time point, t _BBe V _OcvSwitching point V is put and discharged and recharged to the value height ₂Corresponding time point.

Because t _BFor discharging and recharging switching point, therefore battery current has larger variation therebetween, can obtain comparatively accurately OCV value.t _aFor beginning the time point of charging beginning, also easily record accurately OCV value therebetween.

At definite V ₂The time SOC _bWhether be higher than in the self study of setting in limited time 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% searches the OCV-SOC curve table that prestores and obtains by the OCV value that measuring and calculating obtains, the SOC value a% of battery in the time of also can directly continuing to use the shutdown of storing before shutdown last time.

In certain embodiments, in order more accurately to obtain the specified electric quantity value of battery, except requiring to discharge and recharge switching point V ₂SOC during corresponding time point _bBe higher than outside the self study upper limit y% of setting, the variable quantity of also setting b% switching point electric current surpasses preset value, and for example under the common battery capacity of panel computer, this preset value is set as 200mA.Because battery transfers discharge to from charging, electric current generally has large variation, can record corresponding open-circuit voltage values V by the above-mentioned method of the present invention at the b% point _{Ocv_b}, then again by searching default OCV-SOC table, obtaining this stylish SOC value (being the b% among the formula 3a), the electric weight that the b% that then uses this value and ampere-hour integration before to obtain is ordered upgrades new battery rated capacity.

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

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

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aThe SOC value is the time point of a%, t in order to begin to charge _FullFor battery is charged to the saturated time point of electric weight;

In an embodiment of the present invention, then the OCV when beginning to charge by calculating searches default OCV-SOC curve to determine its corresponding SOC value a%, then uses FC _OldBattery electric quantity AH when * a% conduct begins to charge _aBe a kind of mode, other mode is when unused time during less than Preset Time, can directly utilize the SOC value a% of the battery before shutdown last time and be used as battery electric quantity AH when beginning to charge _aThe usefulness of calculating.

Adopt this method, because the saturated electric weight of electric weight charging is clear and definite, namely 100%, therefore in formula with respect to needing to search default OCV-SOC curve to determine the algorithm of a high point value of electric weight among the embodiment before, lacked a source of error, its result is more accurate.

Among some embodiment, can set when when charging electric weight be lower than default self study lower limit, namely start the self study process.Certainly, electric weight is lower than default self study lower limit when setting charging simultaneously in the present embodiment, and the electric weight after the charging is higher than the default self study upper limit, the electric weight of battery has larger variation before and after can guaranteeing like this to charge, obtain distributing for the data of match OCV-SOC curve wider, help to improve the accuracy of the OCV-SOC curve that obtains.

Tracking is calculated in the S309 internal resistance in real time: after battery begins discharge from b%, with certain sampling rate sampling battery current and cell voltage, the value of battery current and battery terminal voltage in record a period of time, because internal resistance and open-circuit voltage remain unchanged, can obtain following system of equations in the certain hour section:

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)

For so that division is more accurate, so that Δ V _OutWith Δ I _OutLarge as far as possible, so need to carry out computing with the extreme value of cell voltage in the certain hour and battery current.Therefore in a preferred embodiment, if I _Outmax/ I _OutminOr V _Outmax/ V _OutminThe V that gives up this time period during less than preset value _Ocv

In a preferred embodiment, carrying out internal resistance when battery discharge, to calculate in real time tracking effect better, because when charging, battery current and terminal voltage are relatively stable, Δ V _OutWith Δ I _OutLess, when discharge, because the variation of equipment running load, battery current exists than great fluctuation process, and terminal voltage also produces than great fluctuation process, Δ V _OutWith Δ I _OutLarger.Through experiment, the time period that measuring and calculating battery current and terminal voltage are worth most is that 0.1s to 10s is better, because be lower than 0.1s, the variation of load is not obvious, and battery current and voltage undulation are little; Greater than 10s, the internal resistance of battery and open-circuit voltage might change, thereby the as a result accuracy that causes obtaining is affected.

Simultaneously experiment shows, when battery electric quantity change to surpass 1%, the variation meeting of the internal resistance of cell and open-circuit voltage affected the result who calculates comparatively significantly.

The S310:OCV real-time follow-up.

The real-time internal resistance of cell value that solves is taken back in the equation, calculated real-time battery open circuit voltage value

V _Ocv=V _Outmin+ I _OutmaxR or V _Ocv=V _Outmax+ I _OutminR

Both generally equate or are comparatively approaching, also can get the mean value of twice calculating as last open-circuit voltage values.In some preferred embodiment, with above two V that formula calculates _OcvThere is larger difference, thinks that then the confidence level of respective value leaves a question open, given up.

The S311:SOC real-time follow-up.

Corresponding SOC value when calculating synchronously each OCV point and upgrading, the result who in the process of calculating, utilizes step S306 integration to obtain, computing formula is as follows:

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

If adopt battery to be full of, activate the described method of embodiment of 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 the formula _bTime point for the charging and discharging state switching; When obtaining the OCV-SOC curve, measuring and calculating V _OcvNumerical value, and determine this V _OcvCorresponding time period (the t of numerical value institute _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 default time interval measuring and calculating battery, and storage, the condition of working as like this meets, and after the activation OCV-SOC curvature correction process, the ampere-hour integration data that can conveniently call storage is used for calculating.Certainly in other embodiments, also direct storaging current-time data carries out integration again when needing.

S312: proofread and correct the OCV-SOC curve, when battery discharge finishes to begin to charge again, upgrade the OCV-SOC look-up table with each OCV-SOC respective value segmentation of calculating.

After the OCV-SOC look-up table upgrades, re-start step S304, detect open-circuit voltage, look into the OCV-SOC table and decide the SOC initial value, certainly the OCV-SOC of this moment table is the new OCV-SOC table that self study obtains afterwards, and the OCV-SOC table before it upgrades more can reflect the relation of current battery OCV and SOC exactly.

The S313 shutdown.

In certain embodiments, the OCV-SOC curve self-learning method that uses in above-described embodiment can use separately, need to be applied to the occasion of self study OCV-SOC curve.

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

The above only is embodiments of the invention; be not so limit claim of the present invention; every equivalent structure or equivalent flow process conversion that utilizes instructions of the present invention and accompanying drawing content to do; or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present invention.

Claims (17)

1. the method for a 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 _OcvMay further comprise the steps:

In battery discharge or charging process, gather battery current and the battery terminal voltage of battery according to default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _Outmin, the internal resistance value r account form of 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)

Calculate 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).

2. 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 may further comprise the 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 ₁Begin 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 that prestores ₂Corresponding SOC value b%, the battery electric quantity AH when beginning to charge _a, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, i is the battery current value, t _aBe the time point that begins to charge, t _BTime point for the charging and discharging state switching;

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _c, account form is as follows:

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

T in the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute, t _bTime point for the charging and discharging state switching;

The SOC that obtains according to (formula 4a) _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

3. the method for self study secondary cell OCV-SOC curve according to claim 2 is characterized in that, the condition that activates self study OCV-SOC curve process comprises: AH _a/ FC _OldLess than the self study lower limit x% that sets, and t _bThe time 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 _OldBe the battery specified electric quantity value that prestores.

4. the method for self study secondary cell OCV-SOC curve according to claim 3 is characterized in that, by formula AH _a=FC _Old* a% calculates AH _aValue, wherein a% is the SOC value when beginning to charge, the mode of obtaining a% numerical value is:

Then OCV when beginning to charge by calculating searches default OCV-SOC curve to determine its corresponding SOC value a%;

Or the SOC value a% of battery when directly obtaining the shutdown of storage before the last time shutdown.

5. the method for self study secondary cell OCV-SOC curve according to claim 3 is characterized in that, the condition that activates self study OCV-SOC curve process comprises: comprising time point t _bThe default time period in the variable quantity of electric current surpass preset value.

6. 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 may further comprise the 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 ₁Begin to be charged to electric weight saturation point V _FullThe time, the battery electric quantity AH when beginning to charge _aAnd the ampere-hour integration, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, i is the battery current value, t _aBe the time point that begins to charge, t _FullFor battery is charged to the saturated time point of electric weight;

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _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 the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute;

The SOC that obtains according to (formula 4b) _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

7. the method for self study secondary cell OCV-SOC curve according to claim 6 is characterized in that, the condition that activates self study OCV-SOC curve process comprises: AH _aLess than the self study lower limit AH that sets _x

8. according to claim 2 to the method for the described self study secondary cell of 7 any one OCV-SOC curve, it is characterized in that, in the process of charging and discharge, according to the ampere-hour integration of default time interval measuring and calculating battery, and storage.

9. the method for self study secondary cell OCV-SOC curve according to claim 1 is characterized in that, calculates respectively V according to (formula 2a) and (formula 2b) _Ocv, two V that calculate when two algorithms _OcvDifference during greater than preset value, give up the V of this time period _Ocv

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, gather battery current and the battery terminal voltage of battery according to default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _OutminIn, battery is discharge process, the default time period is 0.1s～10s.

11. 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, gather battery current and the battery terminal voltage of battery according to default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _OutminIn, I _Outmax-I _OutminOr V _Outmax-V _OutminThe V that gives up this time period during less than preset value _Ocv

12. the measuring method of a secondary cell state-of-charge SOC value is characterized in that, may further comprise the steps:

Start;

Detection was apart from unused time last time;

Whether judgement surpasses the default time apart from unused time last time, if surpassed the time of presetting apart from unused time last time, detect battery open circuit voltage OCV value, and search the OCV-SOC curve and determine the SOC initial value, if be no more than the default time apart from unused time last time, the SOC value when shutting down take last time is the SOC initial value;

Begin charging, whether the SOC value is lower than the setting self study lower limit of setting when judging charging, if be lower than the self study lower limit of setting, then activate self study OCV-SOC curve process, the employed method of described self study OCV-SOC curve process is the method for the described self study secondary cell of claim 1 to 11 any one OCV-SOC curve;

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

Detect battery open circuit voltage V _OcvValue, and search the SOC value that the OCV-SOC curve is determined this moment, and pass through the SOC value of ampere-hour integral method calculated for subsequent.

13. an electronic equipment is characterized in that, comprises the secondary cell for power supply, timing module, voltage detection module, current detection module, memory module, display module, processor;

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

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

Described processor comprises open-circuit voltage measuring and calculating module, is used in battery discharge or charging process, gathers battery current and the battery terminal voltage of battery according to default sampling rate, battery current, the maximal value of battery terminal voltage: the I of battery in the record Preset Time section _Outmax, V _OutmaxWith minimum value: I _Outmin, V _Outmin, the internal resistance value r account form of 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)

Calculate 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).

14. electronic equipment according to claim 13 is characterized in that, described processor comprises state-of-charge measuring and calculating module, is used for according to the OCV of the battery of calculating and the current i of battery, and the state-of-charge of measuring and calculating battery is as the V of battery _OcvValue is from low spot V ₁Begin 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 that prestores ₂Corresponding SOC value b%, the battery electric quantity AH when beginning to charge _a, work as AH _aLess than the self study lower limit AH that sets _x, and t _bThe time SOC that obtains according to (formula 5) _bWhen being not less than the self study upper limit y% of setting, activate self study OCV-SOC curve process, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aBe the time point that begins to charge, t _BTime point for the charging and discharging state switching;

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 that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _c, account form is as follows:

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

T in the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute, t _bBe charged to the time point that begins to discharge behind the high point for battery;

Processor is used for the SOC that basis (formula 4a) obtains _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

15. electronic equipment according to claim 14 is characterized in that, described processor is used for when comprising time point t _bThe default time period in the variable quantity of electric current surpass preset value, activate self study OCV-SOC curve process.

16. electronic equipment according to claim 13 is characterized in that, described processor comprises state-of-charge measuring and calculating module, is used for according to the OCV of the battery of calculating and the current i of battery, and the state-of-charge of measuring and calculating battery is as the V of battery _OcvValue is from low spot V ₁Begin to be charged to electric weight saturation point V _FullThe time, according to the OCV-SOC curve calculation V that prestores ₁Corresponding SOC value a% works as AH _aBe lower than and set self study lower limit AH _xThe time, activate self study OCV-SOC curve process, calculate in the following manner new battery specified electric quantity value FC _New:

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

In the formula, FC _OldBe the battery specified electric quantity value that prestores, i is the battery current value, t _aBe the time point that begins to charge, t _FullFor battery is charged to the saturated time point of electric weight;

Battery discharge calculates each V that obtains in (formula 2a) or (formula 2b) _OcvBe worth corresponding SOC _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 the formula _cBe V in (formula 2a) or (formula 2b) _OcvThe corresponding interior time point of time period of value institute;

Processor is used for the SOC that basis (formula 4b) obtains _cAnd (formula 2a) or (formula 2b) V of obtaining _OcvMatch OCV-SOC curve.

17. to the described electronic equipment of 16 any one, it is characterized in that according to claim 13, described processor is used for, and detects apart from unused time last time after start;

Whether judgement surpasses the default time apart from unused time last time, if surpass the default time apart from unused time last time, detects battery open circuit voltage V _OcvValue and is searched the OCV-SOC curve and is determined the SOC initial value, if be no more than the default time apart from unused time last time, the SOC value when shutting down take last time is the SOC initial value;

Begin charging, whether the SOC value is lower than the setting self study lower limit of setting when judging charging, if be lower than the self study lower limit of setting, then activate self study OCV-SOC curve process, the employed method of described self study OCV-SOC curve process is the method for the described self study secondary cell of claim 1 to 10 any one OCV-SOC curve;

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

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

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