Summary of the invention
Object of the present invention is intended at least solve one of above-mentioned technological deficiency.
For this reason, one aspect of the present invention provides a kind of socking out capacity estimation method of lithium ion battery.
Another aspect of the present invention proposes a kind of socking out capacity estimation system of lithium ion battery.
In view of this, the embodiment of one aspect of the present invention proposes a kind of socking out capacity estimation method of lithium ion battery, comprise the following steps: the voltage change ratio of time period obtains step, in the first voltage, second voltage and the very first time of very first time point and the second time point acquisition lithium ion battery o'clock to the electric current in the second time point, to obtain described very first time o'clock according to described the first voltage, described second voltage, point of the described very first time, described the second time point and described electric current to the voltage change ratio in the second time point; And remaining capacity estimation step, according to described very first time o'clock to the voltage change ratio in the second time point and, contrast default invariance curve and obtain the dump energy under current state; Wherein said invariance curve is obtained by following steps: measuring process, and interval Preset Time detects lithium ion battery and is discharged to the voltage and current cut-off voltage process from full power state, and obtains whole discharge time; Voltage change ratio obtains step, the voltage, described electric current and the described voltage change ratio that obtains each Preset Time section whole discharge time that detect according to each Preset Time section; Invariance curve obtains step, dump energy according to the electric current of described each Preset Time section and when obtaining described each Preset Time section described whole discharge time and finishing, and described dump energy and corresponding voltage change ratio are carried out associated to obtain invariance curve.
According to the method for the embodiment of the present invention, by obtaining very first time o'clock voltage change ratio to the second time point, and utilize invariance curve to obtain the dump energy of current state, reduced thus calculated amount and error, improve the estimated accuracy of dump energy, simultaneously simple easy to use.
In one embodiment of the invention, described voltage change ratio acquisition step specifically comprises: the discharge capacity that obtains described each Preset Time section according to the start time of described each Preset Time section, end time and described electric current; The voltage of start time to described each Preset Time section and the voltage of end time carry out difference and calculate acquisition voltage difference; And obtain the voltage change ratio of described each Preset Time section according to the voltage difference of described each Preset Time section and corresponding discharge capacity.
In one embodiment of the invention, described invariance curve obtains step and specifically comprises: the dump energy according to the electric current of described each Preset Time section and when obtaining respectively described each Preset Time section described whole discharge time and finishing; And dump energy when respectively described each time period is finished and corresponding voltage change ratio carry out one to one associated, to obtain described invariance curve.
In one embodiment of the invention, the voltage change ratio of described time period obtains step and specifically comprises: the first voltage, second voltage and the point of the described very first time that obtains described lithium ion battery at very first time point and the second time point be respectively the electric current in described the second time point extremely; Obtain the discharge capacity of described very first time point to described the second time point according to institute's very first time point, described the second time point and described electric current; Described the first voltage and second voltage are carried out to difference, and the ratio that calculates the voltage difference that obtains and described discharge capacity obtains described very first time o'clock to the voltage change ratio in the second time point.
In one embodiment of the invention, the voltage change ratio of described each Preset Time section represents by following formula, and described formula is, dU, and/dQ ,=Δ U,
t/ Δ Q,
cum, wherein, dU ,/dQ, represents the voltage change ratio of described each Preset Time section, Δ U,
tfor the voltage difference of described each Preset Time section, Δ Q,
cumfor the discharge capacity of described each Preset Time section.
In one embodiment of the invention, described very first time o'clock represents by following formula to the voltage change ratio in the second time point, and described formula is, dU/dQ=Δ U
t/ Δ Q
cum, wherein, dU/dQ represents that described very first time o'clock is to the voltage change ratio in the second time point, Δ U
tfor described very first time o'clock is to the voltage difference in the second time point, Δ Q
cumfor described very first time o'clock is to the discharge capacity in the second time point.
In one embodiment of the invention, dump energy when described each Preset Time section finishes obtains by following formula, and described formula is, Δ Q
remain=∫ I, * t,, wherein, Δ Q
remaindump energy while end for described each Preset Time section, I, is the electric current of described each Preset Time section, t, for described each Preset Time is to described whole discharge time.
The present invention embodiment has on the other hand proposed a kind of socking out capacity estimation system of lithium ion battery, comprise: measurement module, interval Preset Time detects lithium ion battery and is discharged to the voltage and current cut-off voltage process from full power state, and obtains whole discharge time; Voltage change ratio obtains module, the voltage, described electric current and the described voltage change ratio that obtains each Preset Time section whole discharge time that detect according to each Preset Time section; Invariance curve obtains module, dump energy according to the electric current of described each Preset Time section and when obtaining described each Preset Time section described whole discharge time and finishing, and described dump energy and corresponding voltage variety are carried out associated to obtain invariance curve; The voltage change ratio of time period obtains module, the first voltage, second voltage and the very first time o'clock that obtains described lithium ion battery in the very first time and the second time be to the electric current in the second time point, to obtain described very first time o'clock according to described the first voltage, described second voltage, point of the described very first time, described the second time point and described electric current to the voltage change ratio in the second time point; And remaining capacity estimation module, obtain the dump energy under current state according to described very first time o'clock to voltage change ratio and described invariance curve in the second time point.
According to the system of the embodiment of the present invention, by obtaining very first time o'clock voltage change ratio to the second time point, and utilize invariance curve to obtain the dump energy of current state, reduced thus calculated amount and error, improve the estimated accuracy of dump energy, simultaneously simple easy to use.
In one embodiment of the invention, described voltage change ratio obtains module and specifically comprises: the first discharge capacity obtains unit, for obtain the discharge capacity of described each Preset Time section according to the start time of described each Preset Time section, end time and described electric current; Computing unit, carries out difference calculating acquisition voltage difference for the voltage of the start time to described each Preset Time section and the voltage of end time; And first voltage change ratio obtain unit, for obtain the voltage change ratio of described each Preset Time section according to the voltage difference of described each Preset Time section and corresponding discharge capacity.
In one embodiment of the invention, the voltage change ratio of described time period obtains module and specifically comprises: electric current and voltage obtains unit, and the first voltage, second voltage and the point of the described very first time that obtains described lithium ion battery at very first time point and the second time point be respectively the electric current in described the second time point extremely; The second discharge capacity obtains unit, for obtain the discharge capacity of described very first time point to described the second time point according to institute's very first time point, described the second time point and described electric current; Second voltage rate of change obtains unit, and for described the first voltage and second voltage are carried out to difference, the ratio that calculates the voltage difference that obtains and described discharge capacity obtains described very first time o'clock to the voltage change ratio in the second time point.
The aspect that the present invention is additional and advantage in the following description part provide, and part will become obviously from the following description, or recognize by practice of the present invention.
Embodiment
Describe embodiments of the invention below in detail, the example of embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has the element of identical or similar functions from start to finish.Be exemplary below by the embodiment being described with reference to the drawings, only for explaining the present invention, and can not be interpreted as limitation of the present invention.
In description of the invention, it will be appreciated that, term " " center ", " longitudinally ", " laterally ", " on ", D score, " front ", " afterwards ", " left side ", " right side ", " vertically ", " level ", " top ", " end ", " interior ", orientation or the position relationship of indications such as " outward " are based on orientation shown in the drawings or position relationship, only the present invention for convenience of description and simplified characterization, rather than device or the element of indication or hint indication must have specific orientation, with specific orientation structure and operation, therefore can not be interpreted as limitation of the present invention.In addition, term " first ", " second " be only for describing object, and can not be interpreted as indication or hint relative importance.
In description of the invention, it should be noted that, unless otherwise clearly defined and limited, term " installation ", " being connected ", " connection " should be interpreted broadly, and for example, can be to be fixedly connected with, and can be also to removably connect, or connect integratedly; Can be mechanical connection, can be also electrical connection; Can be to be directly connected, also can indirectly be connected by intermediary, can be the connection of two element internals.For the ordinary skill in the art, can concrete condition understand above-mentioned term concrete meaning in the present invention.
Fig. 1 is the process flow diagram of the socking out capacity estimation method of lithium ion battery according to an embodiment of the invention.As shown in Figure 1, comprise the following steps according to the socking out capacity estimation method of the lithium ion battery of the embodiment of the present invention: in the first voltage, second voltage and the very first time of very first time point and the second time point acquisition lithium ion battery o'clock to the electric current in the second time point, to obtain very first time o'clock according to the first voltage, second voltage, very first time point, the second time point and electric current to the voltage change ratio (step 101) in the second time point.According to very first time o'clock to the voltage change ratio in the second time point and, contrast default invariance curve and obtain the dump energy (step 103) under current state.
According to the method for the embodiment of the present invention, by obtaining very first time o'clock voltage change ratio to the second time point, and utilize invariance curve to obtain the dump energy of current state, reduced thus calculated amount and error, improve the estimated accuracy of dump energy, simultaneously simple easy to use.
In step 101, respectively in the first voltage, second voltage and the very first time of very first time point and the second time point acquisition lithium ion battery o'clock to the electric current in the second time point.Obtain very first time o'clock discharge capacity to the second time point according to institute's very first time point, the second time point and electric current.The first voltage and second voltage are carried out to difference, and the ratio that calculates the voltage difference that obtains and discharge capacity obtains very first time o'clock to the voltage change ratio in the second time point.
In one embodiment of the invention, very first time o'clock represents by following formula to the voltage change ratio in the second time point, and formula is, dU/dQ=Δ U
t/ Δ Q
cum, wherein, dU/dQ represents that very first time o'clock is to the voltage change ratio in the second time point, Δ U
tfor very first time o'clock is to the voltage difference in the second time point, Δ Q
cumfor very first time o'clock is to the discharge capacity in the second time point.
Fig. 2 is the product process figure of invariance curve according to an embodiment of the invention.As shown in Figure 2, the generation of invariance curve comprises the following steps: interval Preset Time detects lithium ion battery and is discharged to the voltage and current cut-off voltage process from full power state, and obtains whole discharge time (step 201).Voltage, the electric current detecting according to each Preset Time section and obtain the voltage change ratio (step 203) of each Preset Time section whole discharge time.Dump energy according to the electric current of each Preset Time section and when obtaining each Preset Time section whole discharge time and finishing, and dump energy and corresponding voltage change ratio are carried out associated to obtain invariance curve (step 205).
In step 201 and step 203, obtain the discharge capacity of each Preset Time section according to the start time of each Preset Time section, end time and electric current.The voltage of start time to each Preset Time section and the voltage of end time carry out difference and calculate acquisition voltage difference.Obtain the voltage change ratio of each Preset Time section according to the voltage difference of each Preset Time section and corresponding discharge capacity.
In one embodiment of the invention, the voltage change ratio of each Preset Time section represents by following formula, and formula is, dU, and/dQ ,=Δ U,
t/ Δ Q,
cum, wherein, dU ,/dQ, represents the voltage change ratio of each Preset Time section, Δ U,
tfor the voltage difference of each Preset Time section, Δ Q,
cumfor the discharge capacity of each Preset Time section.
In step 205, the dump energy according to the electric current of each Preset Time section and when obtaining respectively each Preset Time section whole discharge time and finishing.It is associated that dump energy when respectively each time period end and corresponding voltage change ratio carry out one to one, to obtain invariance curve.
In one embodiment of the invention, dump energy when each Preset Time section finishes obtains by following formula, and formula is, Δ Q
remain=∫ I, * t,, wherein, Δ Q
remaindump energy while end for each Preset Time section, I, is the electric current of each Preset Time section, t, for each Preset Time is to whole discharge time.
In one embodiment of the invention, to discharge under standard discharge current, start until battery terminal voltage reaches discharge cut-off voltage from full power state.By the accumulated discharge electric weight Δ Q of unit of the each Preset Time section of discharge process,
cum, and the poor Δ U of cell voltage corresponding to the start-stop moment of each Preset Time section,
t, calculate the cell voltage rate of change dU of each Preset Time section ,/dQ,, i.e. dU ,/dQ ,=Δ U,
t/ Δ Q,
cum.In the time calculating the socking out capacity of each Preset Time section, from battery discharge cut-off time, carry out electric weight reverse integral, obtain the remaining battery discharge capacity Q of certain Preset Time section correspondence
remain.With the voltage change ratio dU of this demarcation ,/dQ, with socking out capacity Q
remainrelation as the basis of estimating battery remaining power in real-time application.
In one embodiment of the invention, at the very first time point t compared with minor time slice
1(zero hour) and the second time point t
2(finish time) upper accumulated discharge capacity Δ Q that calculates lithium battery
cum=∫ I*t.The first voltage U
t1with second voltage U
t2voltage difference delta U
t=U
t1-U
t2.Thereby obtain voltage change ratio dU/dQ=Δ U corresponding to this time period
t/ Δ Q
cum.In discharge process, calculate in real time current voltage change ratio dU/dQ, and detect its numerical value change.
By the voltage change ratio dU/dQ calculating in real time and the corresponding relation (dU/dQ-Q that demarcates the voltage change ratio-socking out capacity obtaining
remain) contrast, determine by lookup table mode the socking out capacity Q that battery is current
remain.
Fig. 3 is according to the graph of a relation of the lithium ion battery of embodiment of the present invention voltage and socking out capacity in discharge process.As shown in Figure 3, the socking out capacity of full power state is designated as Q
remain, full, battery discharge cut-off voltage is U
t,
end.Along with the voltage of discharge battery reduces gradually, socking out capacity reduces gradually.In just section of the electric discharge of lithium ion battery, voltage drop is comparatively slow, and therefore to change corresponding change in voltage less for unit quantity of electricity.At battery discharge latter end, voltage drop is very fast, and unit quantity of electricity changes corresponding change in voltage than the first section of electric discharge greatly.Therefore can determine by detecting change in voltage dU/dQ corresponding to unit accumulation electric weight the discharge condition of lithium ion battery, and definite socking out capacity.Decline rapidly because lithium ion battery has electric discharge latter end voltage, therefore this method is applicable to different types of lithium ion battery.
Fig. 4 is according to the schematic diagram of the similarity of the cell voltage under different discharge currents of the embodiment of the present invention and socking out capacity.As shown in Figure 4, there is similar corresponding relation with socking out capacity in battery terminal voltage under different discharge currents, and this rule is mainly present in the latter end of lithium-ion electric tank discharge.Suppose three groups of different discharge current I
1, I
2and I
3, wherein I
1be less than I
2, I
2be less than I
3, the discharge curve under three groups of electric currents as shown in Figure 4.In Fig. 4, the socking out capacity of full power state is designated as Q
remain, full, battery discharge cut-off voltage is U
t,
end.Wherein at electric discharge latter end, at the identical A of discharge curve voltage change ratio
1, A
2and A
3point, the socking out capacity Q of battery
remain, 1, Q
remain, 2and Q
remain, 3be more or less the same.Therefore under different discharge currents, just can estimate the socking out capacity Q of battery by detecting current voltage change ratio dU/dQ
remain.
Fig. 5 is according to the schematic diagram of the relation of the voltage change ratio of the embodiment of the present invention and socking out capacity.As shown in Figure 5, along with the carrying out of discharge process, the voltage change ratio dU/dQ of battery increases gradually, corresponding socking out capacity Q
remainreduce gradually.Battery discharge finishes, and voltage change ratio corresponding to point that socking out capacity is 0 is designated as dU/dQ
end.Suppose that current time is t, the voltage change ratio calculating is dU/dQ (t), and can check in corresponding socking out capacity by the relation curve of voltage change ratio and socking out capacity is Q
remain(t).
According to the method for the embodiment of the present invention, by obtaining very first time o'clock voltage change ratio to the second time point, and utilize invariance curve to obtain the dump energy of current state, reduced thus calculated amount and error, improve the estimated accuracy of dump energy, simultaneously simple easy to use.
Fig. 6 is the structured flowchart of the socking out capacity estimation system of lithium ion battery according to an embodiment of the invention.As shown in Figure 6, comprise according to the socking out capacity estimation system of the lithium ion battery of the embodiment of the present invention: measurement module 100, voltage change ratio obtain module 300, invariance curve obtains module 500, the voltage change ratio of time period acquisition module 700 and remaining capacity estimation module 900.
Particularly, measurement module 100 interval Preset Times detect lithium ion battery and are discharged to the voltage and current cut-off voltage process from full power state, and obtain whole discharge time.Voltage, the electric current that the module 300 that obtains voltage change ratio detects according to each Preset Time section and the voltage change ratio that obtains each Preset Time section whole discharge time.Invariance curve obtains module 500 according to the electric current of each Preset Time section and obtains each Preset Time section whole discharge time the dump energy while end, and dump energy and corresponding voltage variety is carried out associated to obtain invariance curve.The voltage change ratio of time period obtains the first voltage, second voltage and the very first time o'clock that module 700 obtains lithium ion battery in the very first time and the second time to the electric current in the second time point, to obtain very first time o'clock according to the first voltage, second voltage, very first time point, the second time point and electric current to the voltage change ratio in the second time point.Remaining capacity estimation module 900 obtains the dump energy under current state according to very first time o'clock to voltage change ratio and invariance curve in the second time point.
In one embodiment of the invention, voltage change ratio acquisition module 300 specifically comprises: the first discharge capacity obtains unit 310, computing unit 330 and the first voltage change ratio and obtains unit 350.
Particularly, the first discharge capacity obtains unit 310 for obtain the discharge capacity of each Preset Time section according to the start time of each Preset Time section, end time and electric current.Computing unit 330 carries out difference calculating acquisition voltage difference for the voltage of the start time to each Preset Time section and the voltage of end time.The first voltage change ratio obtains unit 350 for obtain the voltage change ratio of each Preset Time section according to the voltage difference of each Preset Time section and corresponding discharge capacity.
In one embodiment of the invention, the voltage change ratio of time period acquisition module 700 specifically comprises: electric current and voltage obtains unit 710, the second discharge capacity obtains unit 730 and second voltage rate of change obtains unit 750.
Particularly, electric current and voltage obtain unit 710 respectively in the first voltage, second voltage and the very first time of very first time point and the second time point acquisition lithium ion battery o'clock to the electric current in the second time point.The second discharge capacity obtains unit 730 for obtain very first time o'clock discharge capacity to the second time point according to institute's very first time point, the second time point and electric current.Second voltage rate of change obtains unit 750 for the first voltage and second voltage are carried out to difference, and the ratio that calculates the voltage difference that obtains and discharge capacity obtains very first time o'clock to the voltage change ratio in the second time point.
In one embodiment of the invention, second voltage variable quantity obtains unit 750 and represents by following formula, dU/dQ=Δ U
t/ Δ Q
cum, wherein, dU/dQ represents that very first time o'clock is to the voltage change ratio in the second time point, Δ U
tfor very first time o'clock is to the voltage difference in the second time point, Δ Q
cumfor very first time o'clock is to the discharge capacity in the second time point.
In one embodiment of the invention, the first voltage change ratio acquisition unit 350 obtains the voltage change ratio of each Preset Time section by following formula, and this formula is dU ,/dQ, and=Δ U,
t/ Δ Q,
cum, wherein, dU ,/dQ, represents the voltage change ratio of each Preset Time section, Δ U,
tfor the voltage difference of each Preset Time section, Δ Q,
cumfor the discharge capacity of each Preset Time section.
In one embodiment of the invention, this formula of dump energy when remaining capacity estimation module 900 is obtained each Preset Time section and finished by following formula is, Δ Q
remain=∫ I, * t,, wherein, Δ Q
remaindump energy while end for each Preset Time section, I, is the electric current of each Preset Time section, t, for each Preset Time is to whole discharge time.
In one embodiment of the invention, to discharge under standard discharge current, start until battery terminal voltage reaches discharge cut-off voltage from full power state.By the accumulated discharge electric weight Δ Q of unit of the each Preset Time section of discharge process,
cum, and the poor Δ U of cell voltage corresponding to the start-stop moment of each Preset Time section,
t, calculate the cell voltage rate of change dU of each Preset Time section ,/dQ,, i.e. dU ,/dQ ,=Δ U,
t/ Δ Q,
cum.In the time calculating the socking out capacity of each Preset Time section, from battery discharge cut-off time, carry out electric weight reverse integral, obtain the remaining battery discharge capacity Q of certain Preset Time section correspondence
remain.With the voltage change ratio dU of this demarcation ,/dQ, with socking out capacity Q
remainrelation as the basis of estimating battery remaining power in real-time application.
In one embodiment of the invention, at the very first time point t compared with minor time slice
1(zero hour) and the second time point t
2(finish time) upper accumulated discharge capacity Δ Q that calculates lithium battery
cum=∫ I*t.The first voltage U
t1with second voltage U
t2voltage difference delta U
t=U
t1-U
t2.Thereby obtain voltage change ratio dU/dQ=Δ U corresponding to this time period
t/ Δ Q
cum.In discharge process, calculate in real time current voltage change ratio dU/dQ, and detect its numerical value change.By the voltage change ratio dU/dQ calculating in real time and the corresponding relation (dU/dQ-Q that demarcates the voltage change ratio-socking out capacity obtaining
remain) contrast, determine by lookup table mode the socking out capacity Q that battery is current
remain.
According to the system of the embodiment of the present invention, by obtaining very first time o'clock voltage change ratio to the second time point, and utilize invariance curve to obtain the dump energy of current state, reduced thus calculated amount and error, improve the estimated accuracy of dump energy, simultaneously simple easy to use.
Although illustrated and described embodiments of the invention above, be understandable that, above-described embodiment is exemplary, can not be interpreted as limitation of the present invention, those of ordinary skill in the art can change above-described embodiment within the scope of the invention in the situation that not departing from principle of the present invention and aim, modification, replacement and modification.