CN101128743B - Accumulator state monitoring device - Google Patents

Abstract

Provided is a battery state monitor device, which can reduce the human and device costs of setting parameters for evaluating the state of a battery, and which can easily cope with dispersions due to vehicular individual differences of the same vehicle kind. In the battery state monitor device, the lower-limit voltage value at the time when a load is connected at an engine starting time with a battery in a substantially new state is measured as an initial reference lower-limit voltage value V<SUB>LIF</SUB>. This initial reference lower-limit voltage value V<SUB>LIF</SUB>, an initial reference open-circuit voltage V<SUB>OIF</SUB> or the open-circuit voltage of the battery, and the information prestored in a storage unit and concerning an internal resistance changing rate to the change in theopen-circuit voltage of the battery are used to derive the reference discharge characteristics of a new battery to the engine-starting load intrinsic to the vehicle. The state of the battery is evaluated by using the reference discharge characteristics.

Description

Accumulator state monitoring device

Technical field

The present invention relates to the accumulator state monitoring device of the state of a kind of supervision accumulator (referring to lead accumulator in this manual).

Background technology

Have following technology in the prior art: the dropping voltage characteristic of the accumulator during according to engine start etc. during discharge carries out the detection (for example patent documentation 1) of battery condition (for example recession level or charging surplus etc.).The intrinsic load of vehicle when this dropping voltage characteristic and battery discharging is closely related, and therefore in this prior art, the various parameters that are used to carry out the battery condition assessment are set respectively according to vehicle.

Patent documentation 1: the Jap.P. spy opens the 2004-190604 communique

But in above-mentioned prior art, because being used to carry out the various parameters of battery condition assessment sets respectively according to vehicle, therefore the human cost and the installation cost that carry out parameter setting increase, and are difficult to the fluctuation that the vehicle individual differences in the corresponding same vehicle causes simultaneously.

Summary of the invention

Therefore, the problem that will solve of the present invention is to provide a kind of accumulator state monitoring device and method for monitoring, it can alleviate the required human cost and the installation cost of parameter setting of the state estimation that is used to carry out accumulator, and is easy to tackle the fluctuation that the vehicle individual differences in the same vehicle produces.

In order to address the above problem, first mode of the present invention is a kind of accumulator state monitoring device, the combination original state of accumulator that carries on its store car and above-mentioned vehicle, utilize all the time the prestarting voltage of above-mentioned accumulator and the roughly minimum voltage during starting, relatively original state and the state when using monitor to it is characterized in that the residual capacity and the decline state of above-mentioned accumulator thus, have: detecting unit, detect the output voltage of above-mentioned accumulator; First storage unit, the storage first information, this first information represent to be in substantially the relation of the variation of the variation above-mentioned accumulator, open-circuit voltage values of new product state and internal resistance value; Processing unit, according to the above-mentioned first information of storing in above-mentioned first storage unit, magnitude of voltage when initial baseline open-circuit voltage values and initial baseline discharge, derive the benchmark flash-over characteristic, wherein said initial baseline open-circuit voltage values be with new product roughly and roughly at full capacity the above-mentioned accumulator of charged state be object, by the detected open-circuit voltage values of above-mentioned detecting unit, magnitude of voltage is to connect predetermined load on the above-mentioned accumulator of charged state at full capacity and when discharging being roughly new product and roughly being in during the discharge of described initial baseline, by the detected output voltage values of above-mentioned detecting unit, described benchmark flash-over characteristic is represented the variation of the above-mentioned open-circuit voltage values that above-mentioned accumulator is relevant, the relation of the variation of magnitude of voltage when the output voltage values that goes out with discharge examination by above-mentioned predetermined load promptly discharges; With second storage unit, store second information, magnitude of voltage when this second information is above-mentioned initial baseline open-circuit voltage values and the discharge of above-mentioned initial baseline, described accumulator state monitoring device is by having above-mentioned each unit, do not need each above-mentioned accumulator and vehicle are set intrinsic parameter separately, just can derive the said reference flash-over characteristic.

The feature of second mode of the present invention is that in the described accumulator state monitoring device of first mode, the open-circuit voltage of establishing above-mentioned accumulator respectively is V _OI, above-mentioned accumulator discharge the time voltage be V _LI, above-mentioned initial baseline open-circuit voltage values is V _OIF, magnitude of voltage is V during the discharge of above-mentioned initial baseline _LIF, above-mentioned accumulator internal resistance be R _BI, be roughly new product and roughly be at full capacity that the internal resistance value of the above-mentioned accumulator of charged state is R _BIFThe time, the above-mentioned first information is by function f (V _OI)=R _BI/ R _BIFProvide, the said reference flash-over characteristic is by V _LI={ V _LK/ [(V _OI-V _LK) f (V _OI)+V _LK] V _OIProvide, wherein V _LK=(V _LIF/ V _OIF) V _OI

The feature of Third Way of the present invention is, in the described accumulator state monitoring device of first or second mode, above-mentioned processing unit, according to the said reference flash-over characteristic, use beginning back open-circuit voltage values, magnitude of voltage during with the discharge of use beginning back, derive the decline degree and the charging redundancy of above-mentioned accumulator, wherein said use begin the back open-circuit voltage values be with uses above-mentioned accumulator after beginning as object by the detected open-circuit voltage values of above-mentioned detecting unit, it is when above-mentioned predetermined load is discharged with using above-mentioned accumulator after beginning to be connected, by the detected output voltage values of above-mentioned detecting unit that described use begins when discharge back magnitude of voltage.

The feature of cubic formula of the present invention is, in the described accumulator state monitoring device of Third Way, above-mentioned processing unit, magnitude of voltage is poor when beginning the back discharge according to the poor and above-mentioned initial baseline open-circuit voltage values of above-mentioned initial baseline open-circuit voltage values and corresponding open-circuit voltage values and above-mentioned use, obtain above-mentioned decline degree, wherein said corresponding open-circuit voltage values is on the said reference flash-over characteristic and above-mentioned use begins the open-circuit voltage values of when discharge back magnitude of voltage correspondence.

The feature of the 5th mode of the present invention is, in the described accumulator state monitoring device of Third Way, above-mentioned processing unit, try to achieve first ratio, this first ratio is that above-mentioned initial baseline open-circuit voltage values and above-mentioned use begin the poor of when discharge back magnitude of voltage, ratio with respect to the difference of above-mentioned initial baseline open-circuit voltage values and corresponding open-circuit voltage values, wherein said corresponding open-circuit voltage values is on the said reference flash-over characteristic and above-mentioned use begins the open-circuit voltage values of when discharge back magnitude of voltage correspondence, try to achieve minimum use and begin the back open-circuit voltage values, so that second ratio and above-mentioned first ratio equate, wherein said minimum use begins the open-circuit voltage values of back open-circuit voltage values when being to use the charging surplus of the above-mentioned accumulator after the beginning to be roughly zero, described second ratio is that above-mentioned initial baseline open-circuit voltage values and above-mentioned minimum use begin the poor of back open-circuit voltage values, ratio with respect to the difference of above-mentioned initial baseline open-circuit voltage values and minimum benchmark open-circuit voltage values, to be above-mentioned accumulator be roughly open-circuit voltage values when zero for new product state charging surplus down roughly to this minimum benchmark open-circuit voltage values, begin the poor of back open-circuit voltage values according to above-mentioned initial baseline open-circuit voltage values and above-mentioned minimum use, and above-mentioned use begins the back open-circuit voltage values and above-mentioned minimum use begins the poor of back open-circuit voltage values, tries to achieve above-mentioned charging redundancy.

According to first and second mode of the present invention, change the variation pattern of internal resistance value variation, accumulator of corresponding open-circuit voltage values with respect to the residual capacity of new product accumulator roughly, not general simultaneously substantially in the grade of accumulator etc. yet.Therefore, the first information according to the variation pattern of representing the internal resistance value corresponding with the variation of this open-circuit voltage values, magnitude of voltage during the initial baseline discharge of the accumulator when being in new product state roughly, with the corresponding initial baseline sparking voltage value of predetermined load (it can be that each vehicle is intrinsic), can obtain as the state estimation benchmark of accumulator automatically, the benchmark flash-over characteristic of the variation pattern of the sparking voltage value that expression is corresponding with the variation of the open-circuit voltage values that is in the accumulator down of new product state roughly, and need not according to each accumulator and the intrinsic parameter of the independent setting of vehicle.Consequently, can alleviate the human cost and the installation cost that are used to carry out parameter setting, and be easy to tackle the fluctuation that the vehicle individual differences in the same vehicle produces.

And, the predetermined load that carries out being connected with accumulator when initial baseline sparking voltage value detects can be the intrinsic load of each vehicle, therefore use the intrinsic load of vehicle as predetermined load, thereby can obtain the accumulator assessment benchmark intrinsic flash-over characteristic, that vehicle is intrinsic that has reflected when the load that this vehicle is intrinsic is connected to accumulator automatically.

According to Third Way of the present invention, processing unit according to the benchmark flash-over characteristic, use beginning back open-circuit voltage values, and magnitude of voltage when using the discharge of beginning back, derive the decline degree and the charging redundancy of accumulator, therefore need not to set intrinsic parameter separately and can try to achieve decline degree and charging redundancy according to each accumulator and vehicle.

According to cubic formula of the present invention, processing unit is according to poor, and the initial baseline open-circuit voltage values and magnitude of voltage poor when using the discharge of beginning back of initial baseline open-circuit voltage values and corresponding open-circuit voltage values, try to achieve the decline degree of accumulator, therefore can try to achieve the decline degree of accumulator by simple calculating.

And, can not rely on the charging redundancy of accumulator and the decline degree of the accumulator inscribed when trying to achieve each.

According to the 5th embodiment of the present invention, processing unit according to initial baseline open-circuit voltage values and minimum use begin the back open-circuit voltage values poor, and use beginning back open-circuit voltage values and minimum use to begin the poor of back open-circuit voltage values, try to achieve the charging redundancy of accumulator, therefore can try to achieve the charging redundancy of accumulator by simple calculating.

And, can not rely on the decline degree of accumulator and the charging redundancy of the accumulator inscribed when trying to achieve each.

Purpose of the present invention, feature, environment, and advantage can be able to clearly by the following detailed description and the accompanying drawings.

Description of drawings

The chart of the measurement result of the lower voltage limit when Fig. 1 is expression to decline situation and the different accumulator of charging surplus by experimental measurement open-circuit voltage and engine start.

Fig. 2 is the chart that is used to illustrate the flash-over characteristic of accumulator when engine start.

Fig. 3 is the circuit diagram of relation that is connected to the internal resistance of the load of accumulator and accumulator when schematically representing engine start.

Fig. 4 is the chart of the passing of the output voltage when utilizing the JIS capacity test to measure new product battery discharging.

Fig. 5 is the chart of the passing of the expression internal resistance rate of change relative with the open circuit voltage variations of following discharge generation.

Fig. 6 is used to illustrate the chart of principle that carries out the state estimation of accumulator according to the flash-over characteristic of the accumulator of deriving when the engine start.

Fig. 7 is the block diagram of the accumulator state monitoring device of an embodiment of the invention.

Fig. 8 is the process flow diagram that the bulk treatment of the accumulator state monitoring device of presentation graphs 7 is moved.

Embodiment

(principle explanation)

Before the accumulator state monitoring device that an embodiment of the invention are related to is specifically described, the assessment principle of the battery condition that present embodiment relates to is described earlier.

The chart of the measurement result of the lower voltage limit when Fig. 1 is expression to decline situation and the different accumulator of charging surplus by experimental measurement open-circuit voltage (output voltage when accumulator discharges in fact) and engine start (minimum voltage during the output voltage decline of the discharge accumulator during because of engine start, the voltage during discharge that is equivalent to the present invention relates to).Its transverse axis is corresponding to the open-circuit voltage values of the accumulator before beginning when the engine start in each discharge test to discharge, the longitudinal axis corresponding in each discharge test when the engine start lower voltage limit value of the accumulator in the discharge.And, curve G1 among Fig. 1 is according to the measurement result of new product (come down to new product and get final product (down together)) accumulator is described to form, curve G2～G4 is according to the measurement result of using of the accumulator of decline is to a certain extent described to form, order according to curve G2, G3, G4, the service time of accumulator is elongated, the decline aggravation.And, the open-circuit voltage values when (when engine stops) beginning through certain hour when using from complete charge, the flash-over characteristic of accumulator 1 obtains, the precision of state estimation etc. can further improve.

According to the chart of Fig. 1 as can be known, along with accumulator decline aggravation, corresponding curve G1～G4 moves to chart roughly right-hand (or lower right).Particularly in the lower voltage limit value zone following, be the tendency that the curve G2～G4 of benchmark exists the aggravation of failing along with corresponding accumulator to increase to right-hand amount of movement with curve G1 as can be known for predetermined reference level (for example 9V).So, if derive and flash-over characteristic when engine start of the new product accumulator of curve G1 correspondence (with corresponding to each sparking voltage value of each charging surplus relative in engine start the time lower voltage limit value in discharging), just can carry out the state estimation of accumulator as benchmark.

But the situation of load that is connected to accumulator during engine start is different and greatly different according to vehicle.Therefore when utilizing existing method to obtain with flash-over characteristic when the engine start of the accumulator of curve G1 correspondence, for example be the flash-over characteristic when detecting accumulator with curve G1 correspondence in engine start by test under certain base condition, utilize the adjusting parameter of setting according to each vehicle that this flash-over characteristic is finely tuned.

Therefore, the problem that the present application people is conceived in this existing method has been carried out the present invention, flash-over characteristic the during engine start of the load state the during engine start that can obtain the intrinsic reflection of car body automatically so that do not use the intrinsic adjusting parameter of car body etc.Its principle is as follows.

Fig. 2 is the chart that is used to illustrate the flash-over characteristic of accumulator when engine start, and the curve G1 in the chart of Fig. 2 is corresponding to the curve G1 of Fig. 1.Load L during the engine start that is connected with accumulator 1 when as shown in Figure 3, establishing engine start _SThe resistance value of (load beyond the internal resistance of accumulator comprises trigger, other resistance key elements etc.) is R _S, accumulator 1 internal resistance value be R _B, accumulator 1 open-circuit voltage values be V _O, load L during with engine start _SBe connected to accumulator 1 and the minimum lower voltage limit value of the output voltage when discharging is V _L, these parameters R then _S, R _B, V _O, V _LBetween have following relation.

(mathematical expression 1)

$\frac{R_s}{R_B}=\frac{V_L}{V_0-V_L}...\left(1\right)$

According to this mathematical expression (1) to V _LFind the solution, then be shown below.

(mathematical expression 2)

$V_L=\frac{R_S}{R_S+R_B}{V}_O...\left(2\right)$

In this mathematical expression (2), case of internal resistance value R _BNot because of open-circuit voltage values V _O(being the charging surplus of accumulator 1) and change, then load L during engine start _SResistance value R _SDo not depend on open-circuit voltage values V _OAnd keep constant, therefore obtain and mathematical expression (the expression value V of the straight line G5 correspondence of the initial point of the coordinate system of the chart by Fig. 2 _O, V _LThe mathematical expression of proportionate relationship).

In fact, the internal resistance value R in the mathematical expression (2) _BAlong with open-circuit voltage values V _OThe minimizing of (the charging surplus of accumulator 1) and increasing, so lower voltage limit value V _LSuppression ratio for example shown in the curve G1, along with open-circuit voltage values V _OMinimizing and increase.That is, the curve G1 of the chart of Fig. 2 from straight line G5 to the amount of deviating from of longitudinal axis negative direction along with open-circuit voltage values V _OMinimizing and increase gradually, be because internal resistance value R _BFollow open-circuit voltage values V _OMinimizing and increase.

Therefore, the internal resistance value R of accumulator 1 _BFollow open-circuit voltage values V _OThe minimizing of (the charging surplus of accumulator 1) and the increase ratio that increases, so long as 1 on new product accumulator is basic identical in each accumulator 1, the present application people is conceived to this characteristic, associate by effectively utilizing this characteristic load L in the time of can easily detecting the engine start with new product accumulator 1 _SThe flash-over characteristic that corresponding vehicle is intrinsic.

That is, obtain in advance with new product accumulator 1 in follow open-circuit voltage values V _OThe internal resistance value R of minimizing _BThe relevant information of increase ratio, and store in the system, finish vehicle when assembling, when dispatching from the factory in factory, when vehicle is handed to the terminal user or after delivering the terminal user certain during in etc. accumulator 1 when being in the new product state, load L when having utilized engine start with respect to accumulator 1 by measurement _SFlash-over characteristic (connect open-circuit voltage values V as the new product accumulator 1 under the charging surplus of benchmark _OLoad L during with engine start _SThe time lower voltage limit value V _L), obtain the intrinsic measurement point of vehicle on the chart of Fig. 2, according to this measurement point and storage in advance with internal resistance value R _BThe relevant information of increase ratio, load L in the time of can obtaining the engine start with new product accumulator 1 _SThe flash-over characteristic that corresponding vehicle is intrinsic.In addition, about the intrinsic measurement point of above-mentioned vehicle, also can utilize having carried out repeatedly measuring the measurement point of averaging of measurement result numerical value such as (the comprising weighted mean) processing that is obtained, can consider following method etc. in this case: the value of the open-circuit voltage (charging surplus) of the accumulator 1 during according to measurement is preferentially used the measurement point of open-circuit voltage maximum, or strengthens the average weighted expenditure of doing.

Particularly, at first, the charging surplus by experimental measurement new product accumulator 1 is (the open-circuit voltage values V when being essentially at full capacity that charged state get final product (down together) of charged state at full capacity _OIFAnd internal resistance value R _BIF, each open-circuit voltage values V when descending with the charging surplus _OIUnder internal resistance value R _BIWith respect to R _BIFRate of change (R _BI/ R _BIF).And, for the open-circuit voltage values V of new product accumulator 1 _OIThe corresponding internal resistance value R of variation _BIRate of change (R _BI/ R _BIF), approximate trying to achieve with open-circuit voltage values V _OIFunction (for example such function of mathematical expression (3)) for variable will store in the system in advance with the information of this functional dependence.Perhaps as its variation, also can be with each open-circuit voltage values V _OIValue and corresponding with it internal resistance value R _BIRate of change (R _BI/ R _BIF) each value make tables of data and also store in the system in advance.In addition, discuss each open-circuit voltage values V after a while _OIIn internal resistance value R _BIRate of change (R _BI/ R _BIF) concrete measuring method.

(mathematical expression 3)

$\frac{R_{\mathrm{BI}}}{R_{\mathrm{BIF}}}=f\left(V_{\mathrm{OI}}\right)...\left(3\right)$

Then, when accumulator 1 is in new product state and accumulator 1 for charged state at full capacity when the assembling of the vehicle of factory is finished etc., measure open-circuit voltage values (initial baseline sparking voltage value) V _OIF, and this accumulator 1 load L when connecting engine start _SThe time lower voltage limit value (the initial baseline lower voltage limit value) V of accumulator 1 _LIFWhether accumulator 1 is that the judgement of charged state is at full capacity for example carried out by the following method: measure the open-circuit voltage values of accumulator 1, judge that whether this value is more than the reference level of being scheduled to full load charged state correspondence.And as mentioned above, can carry out repeatedly initial baseline sparking voltage value V _OIFAnd initial baseline lower voltage limit value V _LIFMeasurement, utilize its mean value.

By using this initial baseline sparking voltage value V _OIFAnd initial baseline lower voltage limit value V _LIFMeasurement result, and the function (or equal with it tables of data) of above-mentioned mathematical expression (3), the following expression lower voltage limit value V that provides _LIFollow open-circuit voltage values V _OIVariation and the relational expression that changes, wherein open-circuit voltage values V _OIVariation load L during corresponding to the engine start of the new product accumulator 1 that carries on the vehicle _S

(mathematical expression 4)

$V_{\mathrm{LI}}=\frac{V_{\mathrm{LK}}}{(V_{\mathrm{OI}}-V_{\mathrm{LK}})\&CenterDot;f\left(V_{\mathrm{OI}}\right)+V_{\mathrm{LK}}}\&CenterDot;V_{\mathrm{OI}}...\left(4\right)$

Wherein, the V parameter in the above-mentioned mathematical expression (4) _LK, be that the open-circuit voltage values on the straight line G5 in the chart of Fig. 2 is V _OIThe time the lower voltage limit value, can provide by following mathematical expression (5).

(mathematical expression 5)

$V_{\mathrm{LK}}=\frac{V_{\mathrm{LIF}}}{V_{\mathrm{OIF}}}\&CenterDot;V_{\mathrm{OI}}...\left(5\right)$

The derivation of the relational expression of mathematical expression (4) is for example following to be carried out.That is the coordinate points P in the chart of Fig. 2, _FWhen satisfying the concerning of above-mentioned mathematical expression (1), establishing open-circuit voltage values is V _OIFThe time when charging (at full capacity) internal resistance value R _BBe R _BIFThe time, then obtain following relational expression (6).

(mathematical expression 6)

$\frac{R_{\mathrm{BI}}}{R_{\mathrm{BIF}}}=\frac{V_{\mathrm{LIF}}}{V_{\mathrm{OIF}}-V_{\mathrm{LIF}}}...\left(6\right)$

And, the coordinate points P in the chart of Fig. 2 _IWhen satisfying the concerning of above-mentioned mathematical expression (1), can obtain open-circuit voltage values by above-mentioned mathematical expression (3) is V _OIThe time internal resistance value R _BBe R _B=f (V _OI) R _BIF, therefore obtain following relational expression (7).

(mathematical expression 7)

$\frac{R_S}{f\left(V_{\mathrm{OI}}\right)\&CenterDot;R_{\mathrm{BIF}}}=\frac{V_{\mathrm{LI}}}{V_{\mathrm{OI}}-V_{\mathrm{LI}}}...\left(7\right)$

Therefore, the right of relational expression (6) is updated to the parameter (R on the left side of relational expression (7) _S/ R _BIF), and to V parameter _LIFind the solution, can obtain above-mentioned relation formula (4).

The relational expression of above-mentioned mathematical expression (6) is from other viewpoint, straight line G5 with the chart of Fig. 2 is a benchmark, point on the straight line G5 is moved to longitudinal axis negative direction with the amount of movement with the variation pattern correspondence of the rate of change of the internal resistance value of accumulator 1, thereby derive surplus (each the open-circuit voltage values V that respectively charges _OI) under lower voltage limit value V _LI, the open-circuit voltage values V under the above-mentioned point on the straight line G5 that the internal resistance value of above-mentioned accumulator 1 obtains corresponding to the relation by above-mentioned mathematical expression (3) _OI

Derive like this with open-circuit voltage values V _OIWith lower voltage limit value V _LIThe relevant information of relation, load L when having reflected the intrinsic engine start of vehicle _SResistance value R _S, the therefore state estimation of the accumulator 1 by utilizing load environment that this information can reflect that vehicle is intrinsic etc.

Wherein, the value V in the chart of Fig. 2 _OIE, V _LIEThe open-circuit voltage values and the lower voltage limit value that correspond respectively to new product accumulator 1 charging surplus and be zero when (surplus of charging in fact be zero get final product (down together)).And, V _OIE, V _LIEFor example be 12.8V, 10.5V.

Then, illustrate with new product accumulator 1 in follow open-circuit voltage values V _OThe internal resistance value R of minimizing _BThe adquisitiones of the relevant information of increase ratio.At first, in the present embodiment,, carry out capacity test to new product accumulator 1 according to the JIS specification relevant with the accumulator capacity test.Wherein, the capacity test of JIS specification is meant: making at full capacity, the accumulator of charged state carries out the discharge of constant current value (for example 0.2A), measurement arrives and the required time of charging surplus till being zero corresponding voltage value (for example 10.5V) up to the output voltage of accumulator 1 from discharge beginning, with the multiplication value of this required time and discharge current value (for example 0.2A) as accumulator electric capacity.In addition, also can use JIS standard discharge test condition (current value, temperature etc.) flash-over characteristic in addition as variation.

That is, in the present embodiment, make the new product accumulator 1 of full load charged state carry out the discharge of constant current value (for example 0.2A), measure the passing of the output voltage of accumulator 1 at this moment based on the JIS specification.Curve G7 in the chart of Fig. 4 represents to measure the result of passing of output voltage of the accumulator 1 of this moment, the value V in the chart _AFBe the output voltage values (open-circuit voltage values) of the accumulator 1 of the full load charged state before the discharge beginning, corresponding to above-mentioned value V _OIFValue V _AEBe that charging surplus with accumulator 1 is the open-circuit voltage values of zero corresponding discharge when finishing, corresponding to above-mentioned value V _OIEAnd, value V _BFBe the output voltage values of the accumulator 1 after the discharge beginning, value V _BEBe that charging surplus with accumulator 1 is the output voltage values of zero corresponding discharge when finishing, value T _EExpression and charging surplus are the time of zero corresponding discharge when finishing.And straight line G8 has been similar to minimizing that following the charging surplus that causes of discharge and the passing of the measured value of the open-circuit voltage of the accumulator 1 that changes with straight line.And hypographous zone in this chart is the internal resistance value R that has reflected accumulator 1 _BThe part of the influence that increases along with the minimizing of charging surplus is corresponding to the shadow region in the chart of Fig. 2 and following Fig. 5.

Then, the point of the curve G7 in the chart of Fig. 4 and the extent along the chart y direction of the point on the straight line G8, the internal resistance value R of the accumulator of inscribing during with this 1 _BProportional, the value V of (when charging at full capacity) during therefore according to the discharge beginning _AFWith value V _BFPoor D2 and the ratio (D3/D2) of the poor D3 of each point on the straight line G8 in the discharge process and the each point on the curve G7, can derive each open-circuit voltage values V _OIn internal resistance value R _BRate of change (R _B/ R _BF).Curve G9 in the chart of Fig. 5 represent to derive like this with open-circuit voltage values V _OThe internal resistance value R of variation correspondence _BRate of change (R _B/ R _BF), determine above-mentioned mathematical expression (3) according to this curve G9.

Obtain like this with open-circuit voltage values V _OThe internal resistance value R of variation correspondence _BRate of change (R _B/ R _BF), do not depend on the difference of the grade etc. of accumulator 1 substantially, but in order to improve the applicability to various accumulators 1, the internal resistance value R that preferred use will obtain by the test to various accumulators 1 _BRate of change (R _B/ R _BF) rate of change of equalization.

Then, with reference to Fig. 6 illustrate the relational expression of using above-mentioned mathematical expression (4), (5) (perhaps with this relational expression equivalence with open-circuit voltage values V _OIWith lower voltage limit value V _LIThe assessment principle of the state of accumulator 1 tables of data that foundation is corresponding) (recession level and charging surplus).

The assessment principle of recession level at first is described.Curve G1 in the chart of Fig. 6 as mentioned above, utilize the relational expression store the above-mentioned mathematical expression (4) (5) in the system in advance into (perhaps with this relational expression equivalence with open-circuit voltage values V _OIWith lower voltage limit value V _LIThe tables of data that foundation is corresponding), reach above-mentioned initial baseline open-circuit voltage values V _OIFAnd initial baseline lower voltage limit value V _LIFDerive.The curve G1 of this Fig. 6 and value V _OIF, V _LIFRelevant information is stored in the system, is used for the state estimation of accumulator 1.

And, under the state of use of beginning accumulator 1, during the recession level of assessment accumulator 1, measure: load L during engine start during engine start _SBe connected to accumulator 1 preceding open-circuit voltage, i.e. use and begin back open-circuit voltage values V _ORAnd load L during engine start _SLower voltage limit, use beginning back lower voltage limit value V when being connected to accumulator 1 _LRAt this moment, to need not be charged state at full capacity to the charging surplus of accumulator 1.

Then, with the lower voltage limit value on the curve G1 of the chart of Fig. 6 be and use beginning back lower voltage limit value V _LROpen-circuit voltage values during the value that equates is as corresponding benchmark open-circuit voltage values V _OSDerive, by comparing the initial baseline open-circuit voltage values V that stores as in advance _OIFWith its corresponding benchmark open-circuit voltage values V _OSDifference the first difference value D11 and as initial baseline open-circuit voltage values V _OIFBegin back open-circuit voltage values V with using _ORThe second difference value D12 of difference, the recession level of the accumulator of inscribing when detecting this 1.

This detection principle has been utilized following characteristic: utilize the recession level of the illustrated accumulator of Fig. 11 more little, the measurement point (V on the chart _O, V _L) roughly move to left the closer to curve G1.That is, the recession level of accumulator 1 is more little, the measurement point P11 (V on the chart of Fig. 6 _OR, V _LR) coordinate points P12 on the curve G1 of correspondence, according to the close degree of this measurement point P11 with respect to coordinate points P12, the recession level of assessment accumulator 1.

The assessment principle of charging surplus then is described.The assessment of charging surplus, with the assessment of recession level similarly, the sparking voltage when utilizing the accumulator 1 shown in the curve G1 of chart of Fig. 6 for new product and the relation of lower voltage limit are carried out, and when assessment charging surplus, measure and use beginning back open-circuit voltage values V _ORBegin back lower voltage limit value V with using _LRIn addition, in the storage part 17, the open-circuit voltage when following the charging surplus of the obtaining of internal resistance rate of change, the new product accumulator 1 of above-mentioned mathematical expression (3) to be zero, promptly minimum benchmark open-circuit voltage values V _OIE, stored in advance as initial setting.

And, with the assessment of recession level similarly, with the lower voltage limit value on the curve G1 of the chart of Fig. 6 be and use beginning back lower voltage limit value V _LROpen-circuit voltage values during the value that equates is as corresponding benchmark open-circuit voltage values V _OSDerive.And open-circuit voltage, minimum use when being assumed to be zero for the charging surplus of the accumulator 1 in the moment of bringing into use begin back open-circuit voltage values V _ORE, following derivation.That is, make from the initial baseline open-circuit voltage values V that obtains in advance _OIFDeduct minimum use and begin back open-circuit voltage values V _OREValue D14, with respect to from initial baseline open-circuit voltage values V _OIFDeduct minimum benchmark open-circuit voltage values V _OIEThe ratio of value D13, and from initial baseline open-circuit voltage values V _OIFDeduct and use beginning back open-circuit voltage values V _ORValue D12, with respect to from initial baseline open-circuit voltage values V _OIFDeduct corresponding benchmark open-circuit voltage values V _OSThe ratio of value D11 equate, and derive minimum use and begin back open-circuit voltage values V _ORE

And, by comparing as initial baseline open-circuit voltage values V _OIFBegin back open-circuit voltage values V with minimum use _OREDifference triple difference D21, and as using beginning back open-circuit voltage values V _ORBegin back open-circuit voltage values V with minimum use _OREThe 4th difference value D22 of difference, the charging surplus of the accumulator of inscribing when detecting this 1.

This detection principle has been utilized following characteristic: along with the charging surplus of accumulator 1 reduces from the full load charged state, with the value of the pairing coordinate points P21 of measurement point P11 on the imaginary line L1 of the transverse axis of the chart of Fig. 6, from coordinate points P22 one side of the surplus correspondence of charging at full capacity near and the charging surplus be coordinate points P23 one side of zero condition correspondence.

(apparatus structure)

Fig. 7 is the block diagram of the accumulator state monitoring device that relates to of an embodiment of the invention.This accumulator state monitoring device has current sensor 11, voltage sensor (voltage detection unit) 13, handling part 15, storage part 17 and efferent 19, the state of the accumulator 1 that is used for carrying on the monitoring vehicle as shown in Figure 7.The measure-controlling unit that handling part 15 is equivalent to the present invention relates to and first to the 3rd information process unit, first and second storage unit that storage part 17 is equivalent to the present invention relates to.

Current sensor 11 detects the input and output amount of electric current with respect to accumulator 1.Voltage sensor 13 detects the output voltage of accumulator 1.Handling part 15 has CPU etc., carries out various information processing actions (comprising control action) in order to monitor accumulator 1.Storage part 17 is made of storer etc., is used for stores processor portion 15 and carries out the required information of various information processings actions etc.Efferent 19 is used to export the judged result etc. of the state of accumulator 1.

(whole predetermined action)

The bulk treatment action of this accumulator state monitoring device at first, is described with reference to Fig. 8.Handling part 15 along with the connection of ignition switch in step S1 (hereinafter referred to as the IG switch) 21, carries out the detection action of initial charge surplus in step S2.Detect in the action at this, by the open-circuit voltage of voltage sensor 13 detection accumulators 1, according to the charging surplus (initial charge surplus) of measured value detection accumulator 1 before engine start of this open-circuit voltage.Whether at this moment, carry out accumulator 1 is the judgement of charged state at full capacity.And at the open-circuit voltage of the accumulator 1 of this measurement, the state when being used for the engine start of following step S5 is judged or the benchmark flash-over characteristic of step S6 derives and handles.

Handling part 15 then drives trigger 23 in step S3, along with the starting of not shown engine, need to judge whether the derivation of the benchmark flash-over characteristic of accumulator 1 to handle in step S4.That is, after vehicle assembling is finished, also do not carry out under the situation that the derivation of benchmark flash-over characteristic handles, advance to step S6 and carry out benchmark flash-over characteristic derivation processing, under the situation of having carried out the derivation processing, advance to step S5, state judgment processing when carrying out engine start.The judgement whether derivation of this benchmark flash-over characteristic has been carried out is for example by judging whether mathematical expression (4), the relational expression (or tables of data equivalent with it) that (5) are relevant store in the storage part 17 and carry out.And the derivation of this benchmark flash-over characteristic as long as carry out once in fact when vehicle assembling is finished etc., just need not to carry out once more before changing accumulator 1.Carry out that benchmark flash-over characteristic among the step S6 derive to be handled or step S5 in starting the time state judgment processing after, advance to step S7, start back decline judgment processing.And, the particular content of state judgment processing when discussing benchmark flash-over characteristic derivation processing and starting after a while.

And handling part 15 then carries out after the engine start decline and judges action in step S7.Judge in the action in this starting back decline, detect the electric current that becomes in the accumulator 1 of at full capacity charging (or approaching with it state) by the charging after the engine start by current sensor 11 and flow into situation, judge the decline degree of accumulator 1 according to this electric current inflow situation.

And handling part 15 then carries out the charging control (the charging surplus of accumulator 1 monitors) to accumulator 1 in step S8.In this charging control, measurement current value by accumulative total current sensor 11, predetermined benchmark begins the whole magnitudes of current by accumulator 1 discharge constantly when detecting from engine start successively etc., the charge volume that carries out according to this testing result decision reply accumulator 1.So, travel in the charging surplus of accumulator 1 can remain in the preset range.The control example of charge volume is carried out as the generated energy (output voltage etc.) by the not shown alternator of control.

Decline judgement action and charging control are carried out repeatedly after the engine start of this step S7, S8, stop until engine.

(the benchmark flash-over characteristic derives and handles)

The benchmark flash-over characteristic of carrying out in the step S6 of this explanation at above-mentioned Fig. 8 is handled.Derive the prerequisite of handling as this benchmark flash-over characteristic, need in storage part 17, store the open-circuit voltage values V of expression approx and new product accumulator 1 in advance _OIThe internal resistance value R of variation correspondence _BIRate of change (R _BI/ R _BIF), with open-circuit voltage values V _OIThe information of being correlated with for the such function of the above-mentioned mathematical expression (3) of variable (perhaps with it equivalence with open-circuit voltage values V _OIAnd each open-circuit voltage values V _OIIn internal resistance value R _BIRate of change (R _BI/ R _BIF) set up the information that corresponding tables of data is correlated with).

Handling part 15 is at full capacity during charged state at the detection accumulator 1 according to step S2 only, carries out this benchmark flash-over characteristic and derives and handle, if accumulator 1 is not at full capacity during charged state, does not carry out this derivations processing, for example advances to the processing of step S7.And,, then in step S6, carry out the benchmark flash-over characteristic this moment and derive processing if accumulator 1 becomes charged state at full capacity when engine start next time.

Derive in the processing at this, as mentioned above, engine start load L _SLower voltage limit value when being connected to accumulator 1 is as initial baseline lower voltage limit value V _LIFMeasured by voltage sensor 13, utilize this initial baseline lower voltage limit value V _LIF, the initial baseline open-circuit voltage values V that in step S2 before, measures as open-circuit voltage _OIF, and above-mentioned mathematical expression (3) (or with mathematical expression (3) equivalence tables of data), derive and the intrinsic engine start load L of vehicle _SThe benchmark flash-over characteristic of corresponding new product accumulator 1.That is, the benchmark flash-over characteristic of new product accumulator 1 is followed open-circuit voltage values V as expression _OIVariation, lower voltage limit value V _LIVariation mathematical expression (4) relational expression and derive.Wherein, the parameters R in the mathematical expression (4) _LKObtain by mathematical expression (5).

In the present embodiment, the V of the open-circuit voltage values in the new product accumulator 1 of deriving like this _OIVariation and the V of lower voltage limit value _LIThe relation that changes is kept in the storage part 17 in the mode of relational expression (4), (5), also can be kept in the storage part 17 in the mode with the tables of data of relational expression (4), (5) essence equivalence (longitudinal axis and transverse axis are the coordinate information of curve G1 open-circuit voltage and lower voltage limit, on the expression two-dimensional coordinate).

Derive in the processing in this benchmark flash-over characteristic, this is derived and handles the initial baseline open-circuit voltage values V that uses _OIFAnd initial baseline lower voltage limit value V _LIFBe saved in storage part 17.

(original state judgment processing)

The original state judgment processing of carrying out among the step S5 of above-mentioned Fig. 8 then is described.And this original state judgment processing does not depend on that the charging surplus ground of accumulator 1 carries out, and derives and finishes dealing with but its precondition is the benchmark flash-over characteristic of step S6.

In this starting state judgment processing, as mentioned above, engine start load L _SLower voltage limit value when being connected to accumulator 1 is as using beginning back lower voltage limit value V _LRMeasured by voltage sensor 13, use beginning back lower voltage limit value V according to this _LR, the use as open-circuit voltage of measuring in step S2 before begins back open-circuit voltage values V _OR, and the benchmark flash-over characteristic by step S6 derive the information that processing obtained and stored into storage part 17, the recession level of the accumulator of inscribing when judging this 1 and charging surplus.

The judgment processing of recession level at first is described.At first, by the lower voltage limit value on the curve G1 of the chart of Fig. 6 of relational expression (4), (5) expression of storage in the storage part 17 be and use beginning back lower voltage limit value V _LROpen-circuit voltage values during the value that equates is as corresponding benchmark open-circuit voltage values V _OSDerived.Perhaps, will be for the variable V in mathematical expression (4), (5) _LISubstitution use beginning back lower voltage limit value V _LRThe time variable V _OIValue, as corresponding benchmark open-circuit voltage values V _OSDerive.

Then, by comparing initial baseline open-circuit voltage values V as storage in the storage part 17 _OIFWith its corresponding benchmark open-circuit voltage values V _OSDifference the first difference value D11, and as initial baseline open-circuit voltage values V _OIFBegin back open-circuit voltage values V with using _ORThe second difference value D12 of difference, the recession level of the accumulator of inscribing when detecting this 1.For example, detect the recession level of accumulator 1 with respect to the ratio (corresponding to the dash area C1 of Fig. 6) of the first difference value D11 according to the second difference value D12.

The judgment processing of charging surplus then is described.In this judgment processing, the use that utilizes the judgment processing by recession level to obtain begins back lower voltage limit value V _LRAnd corresponding benchmark open-circuit voltage values V _OSHandle.

Open-circuit voltage, minimum use when the charging surplus of the accumulator of inscribing when then, supposing this 1 is zero begins back open-circuit voltage values V _ORE, following derivation.That is, make from the initial baseline open-circuit voltage values V that obtains in advance _OIFDeduct minimum use and begin back open-circuit voltage values V _OREValue D14, with respect to from initial baseline open-circuit voltage values V _OIFDeduct the minimum benchmark open-circuit voltage values V that stores storage part 17 by initial setting into _OIEThe ratio of value D13, and from initial baseline open-circuit voltage values V _OIFDeduct and use beginning back open-circuit voltage values V _ORValue D12, with respect to from initial baseline open-circuit voltage values V _OIFDeduct corresponding benchmark open-circuit voltage values V _OSThe ratio of value D11 equate, and derive minimum use and begin back open-circuit voltage values V _ORE

And, by comparing as initial baseline open-circuit voltage values V _OIFBegin back open-circuit voltage values V with minimum use _OREDifference triple difference D21, and as using beginning back open-circuit voltage values V _ORBegin back open-circuit voltage values V with minimum use _OREThe 4th difference value D22 of difference, the charging surplus of the accumulator of inscribing when detecting this 1.For example, detect the charging surplus of accumulator 1 with respect to the ratio (corresponding to the dash area C2 of Fig. 6) of triple difference D21 according to the second difference value D22.

(summary)

As mentioned above, according to present embodiment, rate of change with respect to internal resistance variation, accumulator 1 of the open-circuit voltage values of the variation correspondence of the charging surplus of new product accumulator 1, in grade of accumulator 1 etc. is not general simultaneously substantially yet, therefore, according to this internal resistance rate of change, and the intrinsic engine start load L of vehicle under the situation such as assemble when finishing with vehicle _SDropping voltage characteristic when the full load of corresponding accumulator 1 is charged, can obtain the intrinsic flash-over characteristic of vehicle automatically as the accumulator 1 under the new product state of the state estimation benchmark of accumulator 1, and need not to carry out intrinsic parameter setting according to each accumulator and vehicle, thereby can alleviate the human cost and the installation cost that are used to carry out parameter setting, and be easy to tackle the fluctuation that the vehicle individual differences in the same vehicle produces.

And as mentioned above, according to the benchmark flash-over characteristic of accumulator 1, and the flash-over characteristic of the accumulator 1 of discharge generation during the engine start of inscribing when respectively assessing, assess recession level and charging surplus, thereby need not to carry out special countermeasures such as parameter setting, can detect the recession level and the charging surplus of accumulator 1 effectively by simple computing at different automobile types, vehicle individual differences.

And, do not rely on the charging surplus of accumulator 1, the recession level of the accumulator of inscribing in the time of can detecting each 1, and do not rely on the recession level of accumulator 1, the charging surplus of the accumulator of inscribing in the time of can detecting each 1.

And, in the present embodiment, the minimum of the output voltage of the accumulator 1 when carrying out the engine start discharge as the sparking voltage value use of accumulator 1, therefore can obtain the sparking voltage value of the characteristic of effective expression accumulator 1 easily, effectively, and the special discharge of the state estimation that need not to make accumulator 1 be used for accumulator 1 can be assessed the engine start ability of accumulator 1 conscientiously.And its variation is not utilized the discharge of accumulator 1 when engine start yet, and the discharge examination of using other loads to produce goes out the flash-over characteristic of accumulator 1.And, the minimum of the output voltage of the accumulator 1 when using discharge as the sparking voltage value, but for example also can will use as the sparking voltage value through the output voltage values after predetermined blink after the discharge beginning.

And, the benchmark of the charging surplus of the accumulator 1 during as the flash-over characteristic of the accumulator 1 of obtaining the new product state, use charged state at full capacity, therefore the charging surplus of accumulator 1 can be set at normal condition easily and correctly, consequently, can be easily and correctly detect the flash-over characteristic of accumulator 1.In this, the surplus level that also other can be charged is obtained the flash-over characteristic of new product accumulator 1 as benchmark.

And, because the relevant information of internal resistance rate of change to the accumulator 1 of the variation of open-circuit voltage obtains by the discharge test (for example relevant according to accumulator capacity test JIS specification) that makes the steady current discharge, the information of the flash-over characteristic in the time of therefore can obtaining the engine start that is suitable for deriving accumulator 1.

And there is the lower voltage limit value V of the accumulator of inscribing when respectively assessing 1 in the state evaluating method of the accumulator 1 under the above-mentioned embodiment _LRThe low more tendency of high reliability more is therefore in order to ensure the reliability of assessment result, only at lower voltage limit value V _LRFor predetermined reference level is carried out the recession level of accumulator 1 and the judgement of charging surplus when following.

And, also can in the device of Fig. 7 that above-mentioned embodiment relates to constitutes, append the temperature sensor that the temperature of accumulator 1 is measured, with the state estimation of the temperature of considering accumulator 1.Particularly, for example the secondary coordinate information of the relation of the open-circuit voltage of derivation expression new product accumulator 1 at each temperature and lower voltage limit (in this case, consider temperature, also can be described as three-dimensional coordinate information), carry out the state estimation under the temperature in this moment in view of the above, perhaps the value of the parameter (open-circuit voltage, lower voltage limit etc.) of temperature dependent is carried out temperature correction (for example proofread and correct and be the value of standard temperature), and carry out state estimation.

The present invention more than has been described in detail in detail, but above-mentioned explanation all is examples, the present invention is not limited to this.The countless variation of example are not also contained in the scope of the invention.

Claims (5)

1. accumulator state monitoring device, the combination original state of accumulator that carries on the store car and above-mentioned vehicle, utilize all the time the prestarting voltage of above-mentioned accumulator and the minimum voltage during starting, state when relatively original state is with use, monitor the residual capacity and the decline state of above-mentioned accumulator thus, it is characterized in that

Have: detecting unit, detect the output voltage of above-mentioned accumulator;

First storage unit, the storage first information, this first information represent to be in substantially the relation of the variation of the variation above-mentioned accumulator, open-circuit voltage values of new product state and internal resistance value;

Processing unit, according to the above-mentioned first information of storing in above-mentioned first storage unit, magnitude of voltage when initial baseline open-circuit voltage values and initial baseline discharge, derive the benchmark flash-over characteristic, wherein said initial baseline open-circuit voltage values be with new product roughly and roughly at full capacity the above-mentioned accumulator of charged state be object, by the detected open-circuit voltage values of above-mentioned detecting unit, magnitude of voltage is to connect predetermined load on the above-mentioned accumulator of charged state at full capacity and when discharging being roughly new product and roughly being in during the discharge of described initial baseline, by the detected output voltage values of above-mentioned detecting unit, described benchmark flash-over characteristic is represented the variation of the above-mentioned open-circuit voltage values that above-mentioned accumulator is relevant, the relation of the variation of magnitude of voltage when the output voltage values that goes out with discharge examination by above-mentioned predetermined load promptly discharges; With

Second storage unit is stored second information, magnitude of voltage when this second information is above-mentioned initial baseline open-circuit voltage values and the discharge of above-mentioned initial baseline,

Described accumulator state monitoring device does not need each above-mentioned accumulator and vehicle are set intrinsic parameter separately by having above-mentioned each unit, just can derive the said reference flash-over characteristic.

2. accumulator state monitoring device according to claim 1 is characterized in that,

The open-circuit voltage of establishing above-mentioned accumulator respectively is V _OI, above-mentioned accumulator discharge the time voltage be V _LI, above-mentioned initial baseline open-circuit voltage values is V _OIF, magnitude of voltage is V during the discharge of above-mentioned initial baseline _LIF, above-mentioned accumulator internal resistance be R _BI, be roughly new product and roughly be at full capacity that the internal resistance value of the above-mentioned accumulator of charged state is R _BIFThe time,

The above-mentioned first information is by function f (V _OI)=R _BI/ R _BIFProvide,

The said reference flash-over characteristic is by V _LI={ V _LK/ [(V _OI-V _LK) f (V _OI)+V _LK] V _OIProvide, wherein V _LK=(V _LIF/ V _OIF) V _OI

3. accumulator state monitoring device according to claim 1 and 2 is characterized in that,

Above-mentioned processing unit, according to said reference flash-over characteristic, magnitude of voltage when using beginning back open-circuit voltage values and using the discharge of beginning back, derive the decline degree and the charging redundancy of above-mentioned accumulator, wherein said use begin the back open-circuit voltage values be with uses above-mentioned accumulator after beginning as object by the detected open-circuit voltage values of above-mentioned detecting unit, it is when above-mentioned predetermined load is discharged with using above-mentioned accumulator after beginning to be connected, by the detected output voltage values of above-mentioned detecting unit that described use begins when discharge back magnitude of voltage.

4. accumulator state monitoring device according to claim 3 is characterized in that,

Above-mentioned processing unit, magnitude of voltage is poor when beginning the back discharge according to the poor and above-mentioned initial baseline open-circuit voltage values of above-mentioned initial baseline open-circuit voltage values and corresponding open-circuit voltage values and above-mentioned use, obtain above-mentioned decline degree, wherein said corresponding open-circuit voltage values is on the said reference flash-over characteristic and above-mentioned use begins the open-circuit voltage values of when discharge back magnitude of voltage correspondence.

5. accumulator state monitoring device according to claim 3 is characterized in that,

Above-mentioned processing unit,

Try to achieve first ratio, this first ratio be above-mentioned initial baseline open-circuit voltage values and above-mentioned use begin when discharge back magnitude of voltage poor, with respect to the ratio of the difference of above-mentioned initial baseline open-circuit voltage values and corresponding open-circuit voltage values, wherein said corresponding open-circuit voltage values is on the said reference flash-over characteristic and above-mentioned use begins the open-circuit voltage values of when discharge back magnitude of voltage correspondence

Try to achieve minimum use and begin the back open-circuit voltage values, so that second ratio and above-mentioned first ratio equate, wherein said minimum use begins the open-circuit voltage values of back open-circuit voltage values when being to use the charging surplus of the above-mentioned accumulator after the beginning to be roughly zero, described second ratio is that above-mentioned initial baseline open-circuit voltage values and above-mentioned minimum use begin the poor of back open-circuit voltage values, ratio with respect to the difference of above-mentioned initial baseline open-circuit voltage values and minimum benchmark open-circuit voltage values, to be above-mentioned accumulator be roughly open-circuit voltage values when zero for new product state charging surplus down roughly to this minimum benchmark open-circuit voltage values

According to above-mentioned initial baseline open-circuit voltage values and above-mentioned minimum use begin the back open-circuit voltage values poor, and above-mentioned use begins the back open-circuit voltage values and above-mentioned minimum use begins the poor of back open-circuit voltage values, tries to achieve above-mentioned charging redundancy.

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