A kind of prediction technique of lithium ion battery analysis lithium
Technical field
The invention belongs to technical field of lithium ion more particularly to a kind of prediction techniques of lithium ion battery analysis lithium.
Background technique
Lithium ion battery lithium ion battery is as new green energy, in recent years by common concern, current business lithium from
Sub- cell negative electrode material is mainly based on graphitic carbon material, and when the charging of big multiplying power or low temperature are charged, inside battery polarization increases,
Cathode overpotential is larger, and the lithium ion in battery is precipitated on Carbon anode surface, seriously forms Li dendrite, pierces through diaphragm, causes just
Cathode short circuit, security performance are had a greatly reduced quality, and judge that the critical condition of battery core generation analysis lithium can design reasonable charging temperature in advance
Degree and multiplying power guarantee that lithium ion battery works normally.
Currently, judge lithium ion battery whether analyse lithium most common method be by battery different multiplying and at a temperature of fill
Then electricity disassembles battery, naked eyes judge that subjectivity provides analysis lithium state and severity.Such method can only qualitatively judge, and consume
Take a large amount of manpower and material resources, there are also certain security risks in battery dismantling process.
Summary of the invention
In view of this, the technical problem to be solved in the present invention is that providing a kind of prediction technique of lithium ion battery analysis lithium.
The present invention provides a kind of prediction techniques of lithium ion battery analysis lithium, comprising:
S1 lithium ion battery charging process middle-jiao yang, function of the spleen and stomach electrode potential and charging current or rate of charge) are subjected to linear fit, obtained
To slope;
S2 lithium ion battery charge transfer resistance and slope) are subjected to linear fit, at the same according to charge transfer resistance with
The relationship of temperature T obtains the condition model of lithium ion battery charging current or rate of charge and temperature, is predicted according to condition model
The critical analysis lithium charging current or rate of charge of different temperatures.
Preferably, the step S1) in the obtained equation of linear fit be U=kX+b, U is current potential, and k is slope, and b is to cut
Away from X is charging current or rate of charge.
Preferably, the step S1) specifically:
At the same temperature, it is charged using different rate of charge or charging current to lithium ion battery, record anode electricity
Anode potential and charging current or rate of charge are carried out linear fit, obtain slope by position and charge transfer resistance.
Preferably, the temperature is 10 DEG C~60 DEG C.
Preferably, the rate of charge is 0.1~5C.
Preferably, the step S2) in lithium ion battery charge transfer resistance and slope be subjected to linear fit, the side of obtaining
Journey is that k=α * Rct+ β, α, β are constant, and Rct is charge transfer resistance.
Preferably, the charge transfer resistance and the relationship of temperature T meet equation:A, B is
Constant, Ea are activation energy, and R is mol gas constant, and T is absolute temperature, and K is rate constant.
Preferably, the condition model of the lithium ion battery charging current or rate of charge and temperature are as follows:
X be charging current or rate of charge,Ea is activation energy, and R is mole gas
Body constant, T are absolute temperature,A, c is fitting coefficient, and U current potential, b is Linear Quasi in step S1)
The intercept of conjunction.
The present invention provides a kind of prediction techniques of lithium ion battery analysis lithium, comprising: S1) by lithium ion battery charging process
Middle-jiao yang, function of the spleen and stomach electrode potential and charging current or rate of charge carry out linear fit, obtain slope;S2 lithium ion battery charge) is shifted into electricity
Resistance carries out linear fit with slope, while according to the relationship of charge transfer resistance and temperature T, obtaining lithium ion battery charging current
Or the condition model of rate of charge and temperature, the critical analysis lithium charging current or charging times of different temperatures are predicted according to condition model
Rate.Compared with prior art, the present invention can quantitatively prejudge varying environment temperature by Arrhenius formula in the way of modeling
The critical condition for spending lower lithium ion battery analysis lithium, does not have to dismantling battery core, time saving and energy saving, economizes on resources, realizes quantization, accuracy
It is high.
Detailed description of the invention
Fig. 1 is the graph of relation of critical analysis lithium electric current and temperature in the embodiment of the present invention 1;
Fig. 2 is rate of charge when being 0.3C, the photo at battery core interface;
Fig. 3 is rate of charge when being 0.4C, the photo at battery core interface;
Fig. 4 is the graph of relation of critical analysis lithium electric current and temperature in the embodiment of the present invention 2;
When Fig. 5 is that rate of charge is 1C in the embodiment of the present invention 2, the photo at battery core interface;
When Fig. 6 is that rate of charge is 0.6C in the embodiment of the present invention 2, the photo at battery core interface.
Specific embodiment
Below in conjunction with the embodiment of the present invention, technical scheme in the embodiment of the invention is clearly and completely described,
Obviously, described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.Based in the present invention
Embodiment, every other embodiment obtained by those of ordinary skill in the art without making creative efforts, all
Belong to the scope of protection of the invention.
The present invention provides a kind of prediction techniques of lithium ion battery analysis lithium, comprising: S1) by lithium ion battery charging process
Middle-jiao yang, function of the spleen and stomach electrode potential and charging current or rate of charge carry out linear fit, obtain slope;S2 lithium ion battery charge) is shifted into electricity
Resistance carries out linear fit with slope, while according to the relationship of charge transfer resistance and temperature T, obtaining lithium ion battery charging current
Or the condition model of rate of charge and temperature, the critical analysis lithium charging current or charging times of different temperatures are predicted according to condition model
Rate.
It is commercially available that the present invention, which is not particularly limited the source of all raw materials,.
Lithium ion battery charging process middle-jiao yang, function of the spleen and stomach electrode potential and charging current or rate of charge are subjected to linear fit, obtained tiltedly
Rate;This is preferably a step specifically at the same temperature in the present invention, using different rate of charge or charging current to lithium
Ion battery charging, records anode potential and charge transfer resistance, and anode potential and charging current or rate of charge are carried out line
Property fitting;Being fitted obtained equation is preferably U=kX+b, and U is current potential, and k is slope, and b is intercept, and X is charging current or charging
Multiplying power;The temperature is preferably 10 DEG C~60 DEG C;The lithium ion battery is lithium ion battery well known to those skilled in the art
, special limitation is had no, preferably to plate lithium electrode as reference electrode in the present invention;When lithium ion battery changes locating temperature
When degree condition, 30~240min, more preferably 60~200min are preferably first stood, is further preferably 100~180min, most preferably
120~140min, then charged using different rate of charge;To ensure that each charge condition is the same, preferably first put
After electricity, then different rate of charge is used to charge;The electric discharge is preferably carried out using 1C electric current;The preferred electric discharge of electric discharge
To low cutoff voltage;The rate of charge is preferably 0.1~5C;The charging preferably charges to upper limit blanking voltage;Every time
After charging, preferably 1~10min of standing, more preferably 4~8min of standing further preferably stand 5~6min, record anode potential,
Then it after being discharged, then is charged next time;The electric discharge is preferably carried out using 1C electric current.
The charge transfer resistance of record and slope are subjected to linear fit, obtain slope and electric charge transfer electricity under corresponding temperature
The relationship of resistance, the equation are preferred are as follows: k=α * Rct+ β, α, β are constant, and Rct is charge transfer resistance.
Simultaneously according to the relationship of charge transfer resistance and temperature T, i.e. Arrhenius equation, establish charge transfer resistance and
The equation of temperature T is preferred are as follows:Also it can be written asA, B is normal
Number, Ea is activation energy, and R is mol gas constant, and T is absolute temperature, and K is rate constant.
According to the linear fit equation of anode potential and charging current or rate of charge, the line of charge transfer resistance and slope
The relationship of property fit equation and charge transfer resistance and temperature T, obtains lithium ion battery charging current or rate of charge and temperature
Condition model, preferably are as follows:
X be charging current or rate of charge,Ea is activation energy, and R is mole gas
Body constant, T are absolute temperature,A, c is fitting coefficient, and U current potential, b is Linear Quasi in step S1)
The intercept of conjunction;A is preferablyC is preferably equal with the β in slope linear fit equation with lithium ion battery charge transfer resistance.
It can be according to the critical analysis lithium charging current or rate of charge of obtained condition model prediction different temperatures.
Present invention lithium ion at a temperature of Arrhenius formula can quantitatively prejudge varying environment in the way of modeling
Battery analyses the critical condition of lithium, does not have to dismantling battery core, time saving and energy saving, economizes on resources, and realizes that quantization, accuracy are high.
In order to further illustrate the present invention, with reference to embodiments to a kind of lithium ion battery analysis lithium provided by the invention
Prediction technique is described in detail.
Reagent used in following embodiment is commercially available.
Embodiment 1
Battery uses ternary material: NCM523;Anode material: (gram volume plays 340mAh/g, degree of graphitization to graphite AK01
94%);Electrolyte with the lithium hexafluoro phosphate (LiPF6) of concentration 1.0M be lithium salts, using vinylene carbonate as additive, with carbonic acid
The mixture of acrylic ester (PC), ethylene carbonate (EC) and dimethyl carbonate (DMC) is made for solvent;Lithium ion battery is measured to exist
Different multiplying charge when rated condition under anode to lithium current potential Ux。
Embodiment is specifically described as follows:
Battery core is embedded to copper wire in preparatory phase, handles after battery core activation copper wire plating lithium and reference electrode is made;Subsequent battery core
Merging high-low temperature chamber simultaneously accesses charge and discharge cabinet, completes to test by process, collects data.
Specific testing process is as follows:
1) adjustment environment temperature is T (T is the setting of experiment demand);
2) 120min is stood;
3) nominal 1C current discharge is to low cutoff voltage;
4) 5min is stood;
5) upper limit blanking voltage is charged to;
6) 5min is stood.
Record same temperature, under different multiplying, the corresponding current potential U of anodex。
Lithium ion battery charging process middle-jiao yang, function of the spleen and stomach electrode potential and charging current are subjected to linear fit, obtain fit equation U=
KI+b, U are current potential, and k is slope, and b is intercept, and I is electric current.
Test data and linear fit data are shown in Table 1.
1 test data of table and linear fit data
Linear fit is carried out according to the charge transfer resistance of test and slope k obtained above, it is oblique to obtain corresponding temperature
The linear fit equation of rate k and Rct: k=0.8474*Rct+8.9234.
Based on lithium ion battery principle, the equation of Rct Yu temperature T: LnRct=7120.1 (1/T) -21.059 are established.
Based on above-mentioned steps, the equation of critical charging current and temperature is established, obtains lithium ion battery different temperatures analysis lithium
Critical condition model of fit:
I0For charging current or rate of charge,Ea is activation energy, and R is mole gas
Body constant, T are absolute temperature,A, c is fitting coefficient, U current potential, b0It is linear in step S1)
The intercept of fitting, U0Lithium current potential, U are analysed for lithium ion battery0With b0For definite value.
It brings the data in table 1 into model of fit, it is as shown in Figure 1 to obtain matched curve.
According to model, predict that critical analysis lithium multiplying power is 0.3C when 0 DEG C (273.15K).
0 DEG C of temperature of control, successively charges under the conditions of under 0.3C and 0.4C multiplying power, and then dismantling is full by hand in safe house
Charge core and observing interface analysis lithium situation, judges critical analysis lithium multiplying power;When wherein Fig. 2 is rate of charge 0.3C, battery core interface
Photo, no analysis lithium phenomenon, Fig. 3 is rate of charge when being 0.4C, the photo at battery core interface, there is slight analysis lithium;By Fig. 2 and figure
0 DEG C of critical analysis lithium multiplying power of 3 deducibility this lithium ion battery is that 0.3C is consistent with model of fit prediction result.
Embodiment 2
Battery uses ternary material: NCM523;Anode material: (gram volume plays 350mAh/g, graphite to artificial graphite SF01
Change degree 96.5%);Electrolyte with the lithium hexafluoro phosphate (LiPF6) of concentration 1.0M be lithium salts, using vinylene carbonate as additive,
It is made by solvent of the mixture of propene carbonate (PC), ethylene carbonate (EC) and dimethyl carbonate (DMC);Measure lithium ion
Battery different multiplying charge when rated condition under anode to lithium current potential Ux。
Embodiment is specifically described as follows:
Battery core is embedded to copper wire in preparatory phase, handles after battery core activation copper wire plating lithium and reference electrode is made;Subsequent battery core
Merging high-low temperature chamber simultaneously accesses charge and discharge cabinet, completes to test by process, collects data.
Record same temperature, under different multiplying, the corresponding current potential U of anodex。
Lithium ion battery charging process middle-jiao yang, function of the spleen and stomach electrode potential and charging current are subjected to linear fit, obtain fit equation U=
KI+b, U are current potential, and k is slope, and b is intercept, and I is electric current.
Test data and linear fit data are shown in Table 2.
2 test data of table and linear fit data
Linear fit is carried out according to the charge transfer resistance of test and slope k obtained above, it is oblique to obtain corresponding temperature
The linear fit equation of rate k and Rct: k=0.6987*Rct+7.4753.
Based on lithium ion battery principle, the equation of Rct Yu temperature T: LnRct=6440.6* (1/T) -18.678 are established.
Based on above-mentioned steps, the equation of critical charging current and temperature is established, obtains lithium ion battery different temperatures analysis lithium
Critical condition model of fit:
I0For charging current or rate of charge,Ea is activation energy, and R is mole gas
Body constant, T are absolute temperature,A, c is fitting coefficient, U current potential, b0It is linear in step S1)
The intercept of fitting, U0Lithium current potential, U are analysed for lithium ion battery0With b0For definite value.
It brings the data in table 2 into model of fit, it is as shown in Figure 4 to obtain matched curve.
Analysis lithium test at 10 DEG C of verifying, Fig. 5 is rate of charge when being 1C, the photo at battery core interface, there is slight analysis lithium;
Fig. 6 is rate of charge when being 0.6C, and battery core interface is good.Therefore critical analysis lithium multiplying power is between 0.6C and 1C, with fitting mould
Type prediction result is consistent.