A kind of method for shortening the cycle life of lithium ion battery evaluation and test time
Technical field
The present invention relates to a kind of method of lithium ion battery evaluation and test, shortens the lithium ion battery circulation longevity more particularly, to one kind
The method of life evaluation and test time.
Background technology
Due to the non-renewable resources such as coal, oil, natural gas the environmental problem for increasingly reducing and thus bringing not
Disconnected to deteriorate, the development of global economy is to new, and efficiently, the demand of the environmentally friendly energy gradually increases.Lithium ion battery is as a kind of
New energy, because its is environmentally friendly, energy density is high, has extended cycle life, and operating temperature range is wide, and storage time length etc. is excellent
Point so that it is not only used widely in the 3C such as mobile phone, notebook computer, digital camera fields, and in electric tool,
The dynamic fields such as electric automobile, electric bicycle are favored.
In order to ensure the usability of lithium ion battery and security, the reliability and security of lithium ion battery are commented
Survey is particularly important.And the cycle life evaluation and test of lithium ion battery is the most important thing in reliability evaluation and test, it is lithium ion
The key factor that can battery and associated batteries material be produced in batches, its evaluation and test week in all evaluation and test projects
Phase is most long, is the important ring for influenceing new product Time To Market.Different according to the purposes of lithium ion battery, its cycle life is commented
The condition of valency also difference, so that applied to mobile phone, exemplified by lithium ion (aluminum hull) battery of the 3C classes of digital camera class, it is 25
Evaluation result after lower 500 circulations of DEG C normal temperature be capability retention requirement more than 80%, also have for aluminum hull rectangular cell
The requirement of one thickness swelling amount.Evaluation and test for some special battery material properties, the cycle-index of its life assessment are even more
More than thousands of times.According to the difference of discharge and recharge condition, the time of one cycle, completing 500 circulations needed at 3~5 hours or so
The time of more than 90 days is taken, completes to take the time of more than 180 days if 1000 circulations, has thus largely tied down new
The Time To Market of product, it is possible to therefore and lose first chance, market will be seized by other company.Therefore there is an urgent need to a kind of new
Evaluation and test battery cycle life method, can be quick, accurately evaluate and test battery cycle life, greatly shorten cycle life evaluation and test
Time, the quick listing of new product is promoted so as to grab market.
The content of the invention
The present invention provides a kind of method for shortening the cycle life of lithium ion battery evaluation and test time, can shorten lithium ion battery and follow
The evaluation and test time in ring life-span, evaluation cost is reduced, accelerate new product, the importing time of new technology, improve battery production business and phase
Close the product competitiveness of material manufacturer.
The present invention be shorten the technical scheme that uses of cycle life of lithium ion battery evaluation and test time for:
1st, N (4≤N≤10) batteries are chosen, in order to ensure the reliability of evaluation and test, battery is same batch, is randomly selected.
2nd, in the present invention, represent that (1C electric currents are the size of battery capacity to charge-discharge magnification, and 0.1C electric currents are 1/10 electricity with C
Tankage size), SOC represents that (such as SOC0% represents electric discharge state to state-of-charge, and SOC10% represents rechargable battery rated capacity
10%, SOC100% represent full charge state)
3rd, charging is divided into CCV patterns (constant-current charge) and CCCV patterns (constant-current constant-voltage charging) in the present invention, discharges for CCD
Pattern (constant-current discharge).
4th, the present invention in capability retention be circulate terminate after capacity divided by battery rated capacity (such as:Battery
Capacity is 1000mAh, and the capacity after circulation terminates is 860mAh, so 86%) its capability retention is;
5th, a kind of method for the evaluation and test time for shortening cycle life of lithium ion battery, comprises the following steps:
(1) N batteries are respectively labeled as 1,2,3 in above-mentioned to N 1 ..., N (wherein 4≤N≤10);
(2) the N batteries of above-mentioned steps (1) are discharged into 3.00V with 1C;
(3) exhausted cell in above-mentioned steps (2) is subjected to charging process respectively, SOC is charged to labeled as 1 battery
(1/N) stops charging afterwards, records voltage Charge-1 now, and the blanking voltage of the charging of the battery labeled as 1 is set
For Charge-1;Labeled as 2 battery be charged to SOC (2/N) afterwards stop charging, record voltage Charge-2 now,
It is set as Charge-2 labeled as the blanking voltage of the charging of 2 battery;By that analogy, it is charged to SOC labeled as N-1 battery
[(N-1)/N] stops charging afterwards, voltage Charge- (N-1) now is recorded, the charge cutoff of the battery labeled as N-1
Voltage is set as Charge- (N-1);Labeled as N battery, with electric current 0.05C cut-offs, (this is designated as after charging voltage to 4.20V
SOC100%);
(4) the charged battery of above-mentioned steps (3) is subjected to discharge process respectively, labeled as 1 battery discharge to 3.00V
Stop electric discharge (this is designated as SOC0%) afterwards, stop discharging afterwards to SOC (1/N) labeled as 2 battery discharge, record putting now
Piezoelectric voltage Discharge-2, the discharge cut-off voltage of the battery labeled as 2 is set as Discharge-2;By that analogy, mark
The battery discharge for being designated as N-1 stops electric discharge to SOC [(N-2)/N] afterwards, records discharge voltage Discharge- (N- now
1) the battery discharge blanking voltage labeled as N-1, is set as Discharge- (N-1);Labeled as N battery discharge to SOC
[(N-1)/N] stops electric discharge afterwards, records discharge voltage Discharge-N now, and the electric discharge of the battery labeled as N is ended
Voltage is set as Discharge-N;
(5) battery in above-mentioned steps (4) is carried out carrying out cycle life evaluation and test under different SOC sections, labeled as 1
Battery circulates between SOC0%~SOC (1/N), charge cutoff voltage Charge-1, discharge cut-off voltage 3.00V;Mark
It is designated as 2 battery to circulate between SOC (1/N)~SOC (2/N), charge cutoff voltage Charge-2, discharge cut-off voltage is
Discharge-2;By that analogy, circulate, charge between SOC [(N-2)/N]~SOC [(N-1)/N] labeled as N-1 battery
Blanking voltage is Charge- (N-1), and discharge cut-off voltage is Discharge- (N-1);Labeled as N battery in SOC [(N-
1)/N] circulate between~SOC100%, charge using voltage as 4.20V, electric current is 0.05C cut-offs, and discharge cut-off voltage is
Discharge-N;
After (6) 500 cycle-indexes terminate, draw this N batteries circulated under different SOC state of section evaluation and test terminate after
Capability retention, it is the capability retention after circulating battery terminates to obtain average value.For square aluminum-shell battery, also need to electricity
The thickness swelling amount in pond is evaluated and tested, and thickness swelling amount of this N batteries under different SOC state of section is added, drawn
As a result it is the thickness swelling amount of battery.
It is compared with existing evaluation method, the advantages of invention:Provide one kind and be substantially shorter lithium ion cycle life
The method of evaluation time, so as to accelerate the evaluation and test of lithium ion cycle life., can be convenient by this evaluating method, it is quickly right
Battery cycle life is evaluated;On the other hand, the evaluation cost of battery is effectively reduced;In addition, using this evaluating method,
The time of new product listing is largely accelerated, improves the competitiveness in the new product market of company.
Using the evaluating method of cycle life of the present invention, as 4≤N≤10, the evaluation and test time can be not only greatly shortened, its
The accuracy of evaluation and test is high, nor can take too many valuator device.During N=4, the evaluation and test time can shorten 50%~70%, N
When=6, when the evaluation and test time can shorten 65%~75%, N=10, the evaluation and test time can shorten 70%~80%.The evaluation of the present invention
The capacity result and the capacity result deviation of existing evaluation method that method is drawn within 5%, the deviations of thickness results 8% with
It is interior, illustrate that the evaluating method of the present invention and existing evaluating method uniformity are very high.
Brief description of the drawings
Fig. 1 is to shorten the process chart that cycle life evaluates and tests the time.
Fig. 2 is comparative example of the present invention and embodiment circulation volume conservation rate curve;
Fig. 3 is the schematic diagram of battery cycle charge-discharge.
Embodiment
The present invention is described in further detail below in conjunction with drawings and examples.
CGA103450 batteries are used in case of the present invention, it is aluminum hull rectangular cell to use battery, thickness 10mm,
Width is 34mm, is highly 50mm, and positive electrode is ternary LiNi0.5Co0.2Mn0.3O2, negative pole is Delanium and native graphite
Mixing, its capacity is 2000mAh.In order to ensure the reliability of case, battery is selected same batch battery, randomly selected.
All cases are all completed in Japan's equipment, and the circulation of 500 times is completed under 25 DEG C of isoperibols.
Comparative example 1
(1) existing evaluating method is used, chooses 3 batteries, after discharge process, this 3 batteries is carried out with identical conditions
Cycle life is tested.The requirement of evaluation result is 500 circulations, and capability retention is more than 80%, thickness swelling amount <
2.3mm。
(2) table 1:The cycle life test condition of comparative example, shelve in table the time be discharge and recharge it is complete after residence time
(3) time needed for one cycle be 3~4 hours between, complete 500 times circulation will be about 90 days or so when
Between.
(4) after circulation terminates, the capability retention of Section 1 battery is 87.5%, thickness swelling 1.95mm, Section 2 electricity
The capability retention in pond is 88.4%, thickness swelling 2.07mm, and the capability retention of Section 3 battery is 86.5%, and thickness is swollen
Swollen is 1.88mm.The capability retention of battery in summary:(87.5%+88.4%+86.5%) ÷ 3=87.5%, thickness are swollen
Bulk:(1.95+2.07+1.88) ÷ 3=1.97mm.
Embodiment 1
(1) 4 batteries are chosen, are respectively labeled as 1,2,3,4;
(2) by the battery in above-mentioned steps (1) after the processing of discharge and recharge so that each batteries are in different SOC
Under state, each batteries carry out cycle life evaluation and test in different SOC sections, labeled as 1 battery, SOC0%~
Circulated between SOC25%, charge cutoff voltage 3.85V, discharge cut-off voltage 3.00V;Exist labeled as 2 battery
Circulated between SOC25%~SOC50%, charge cutoff voltage 3.90V, electric discharge cut-off condition is 3.67V;Labeled as 3 electricity
Pond is circulated between SOC50%~SOC75%, charge cutoff voltage 4.01V, discharge cut-off voltage 3.75V;Labeled as 4
Battery circulated between SOC75%~SOC100%, charge cutoff condition:Voltage 4.20V, electric current 100mA, electric discharge cut-off electricity
Press as 3.88V;
(3) table 2:For 4 batteries cycle life test condition in case study on implementation 1;
(4) labeled as 1,2,3 battery one cycle the time required to be 50 minutes or so, labeled as 4 circulating battery when
Between be up to 30 minutes or so 1 hour.It is the time needed for the battery labeled as 4 to complete the time needed for cycle life.
So the deadline of cycle life is 30 days or so, the cycle life evaluation and test time 67% can be shortened.
(5) after circulation terminates, the capability retention and thickness of 4 batteries are counted, protected labeled as 1 battery capacity
Holdup is 79.4%, thickness swelling 0.79mm, and the battery capacity conservation rate labeled as 2 is 84.2%, and thickness swelling is
0.51mm, the battery capacity conservation rate labeled as 3 are 87.5%, thickness swelling 0.43mm, are kept labeled as 4 battery capacity
Rate is 89.3%, thickness swelling 0.34mm.In summary, capability retention:(79.4+84.2+87.5+89.3) % ÷ 4=
85.1%, thickness swelling amount:(0.79+0.51+0.43+0.34) mm=2.07mm.Compared with existing evaluating method, capacity is kept
Rate deviation 2.74%, thickness swelling amount deviation are 5.08%.
Embodiment 2
(1) 6 batteries are chosen, are respectively labeled as 1,2,3,4,5,6;
(2) by the battery in above-mentioned steps (1) after the processing of discharge and recharge so that each batteries are in different SOC
Under state, each batteries carry out cycle life evaluation and test in different SOC sections, labeled as 1 battery, in SOC0%~SOC
(1/6) circulated between, charge cutoff voltage 3.81V, discharge cut-off voltage 3.00V;Labeled as 2 battery in SOC (1/6)
~SOC is circulated between (1/3), charge cutoff voltage 3.87V, and electric discharge cut-off condition is 3.65V;Labeled as 3 battery in SOC
(1/3) circulated between~SOC50%, charge cutoff voltage 3.92V, discharge cut-off voltage 3.69V;Labeled as 4 battery
Circulated between SOC50%~SOC (2/3), charge cutoff voltage 3.98, discharge cut-off voltage 3.75V;Labeled as 5
Battery circulates in SOC (2/3)~SOC between (5/6), charge cutoff voltage 4.10V, discharge cut-off voltage 3.80V;Mark
Circulated for 6 battery between SOC (5/6)~SOC100%, charge cutoff condition is:Voltage 4.20V, electric current 100mA, electric discharge
Blanking voltage is 3.94V;
(3) table 3:For 6 batteries cycle life test condition in case study on implementation 2;
(4) the battery one cycle required time labeled as 1,2,3,4,5 is 40 minutes or so, is followed labeled as 6 battery
The ring time is up to 12 minutes or so 1 hour.It is the battery completion circulation labeled as 6 to complete the time needed for cycle life
Time needed for number.So the time for completing 500 circulations is 25 days or so, the cycle life evaluation and test time 73% can be shortened.
(5) after circulation terminates, the battery capacity conservation rate labeled as 1 is 76.5%, thickness swelling 0.55mm;It is labeled as
2 battery capacity conservation rate is 81.6%, thickness swelling 0.43mm;Battery capacity conservation rate labeled as 3 is 83.7%, thick
Degree is expanded to 0.31mm;Battery capacity conservation rate labeled as 4 is 90.6%, thickness swelling 0.29mm;Labeled as 5 battery
Capability retention is 90.8%, thickness swelling 0.25mm, and the battery capacity conservation rate labeled as 6 is 91.3%, thickness swelling
For 0.20mm.In summary, capability retention:(76.5+81.6+83.7+90.6+90.8+91.3) % ÷ 6=85.8%.It is thick
Spend swell increment:(0.55+0.43+0.31+0.29+0.25+0.20) mm=2.03mm.Compared with existing evaluating method, capacity is protected
Holdup deviation 1.94%, thickness swelling amount deviation 3.05%.
Embodiment 3
(1) 10 batteries are chosen, are respectively labeled as 1,2,3,4,5,6,7,8,9,10;
(2) by the battery in above-mentioned steps (1) after the processing of discharge and recharge so that each batteries are in different SOC
Under state, each batteries carry out cycle life evaluation and test in different SOC sections, circulate, fill between SOC0%~SOC10%
Electric blanking voltage is 3.76V, discharge cut-off voltage 3.00V;Followed labeled as 2 battery between SOC10%~SOC20%
Ring, charge cutoff voltage 3.83V, electric discharge cut-off condition are 3.61V;Labeled as 3 battery SOC20%~SOC30% it
Between circulate, charge cutoff voltage 3.87V, discharge cut-off voltage 3.66V;Labeled as 4 battery SOC30%~
Circulated between SOC40%, charge cutoff voltage 3.89V, discharge cut-off voltage 3.68V;Exist labeled as 5 battery
Circulated between SOC40%~SOC50%, charge cutoff voltage 3.91V, discharge cut-off voltage 3.70V;Labeled as 6 electricity
Pond is circulated between SOC50%~SOC60%, charge cutoff voltage 3.96V, discharge cut-off voltage 3.74V;Labeled as 7
Battery, circulated between SOC60%~SOC70%, charge cutoff voltage 4.01V, discharge cut-off voltage 3.78V;Mark
It is designated as 8 battery to circulate between SOC70%~SOC80%, charge cutoff voltage 4.08V, electric discharge cut-off condition is
3.84V;Circulated labeled as 9 battery between SOC80%~SOC90%, charge cutoff voltage 4.16V, electric discharge cut-off electricity
Press as 3.91V;Circulated labeled as 10 battery between SOC90%~SOC100%, charge cutoff condition:Voltage 4.20V, electricity
Flow 100mA, discharge cut-off voltage 4.00V;
(3) table 4:For 10 batteries cycle life test condition in case study on implementation 3;
(4) the battery one cycle required time labeled as 1,2,3,4,5,6,7,8,9 is 25 minutes or so, labeled as 6
The circulating battery time be up to 50 minutes or so.It is needed for the battery labeled as 6 to complete the time needed for cycle life
Time.So the deadline of cycle life is 19 days or so, the cycle life evaluation and test time 79% can be shortened.
(5) after circulation terminates, the capability retention and thickness of 10 batteries are counted, labeled as 1 battery capacity
Conservation rate is 75.4%, thickness swelling 0.29mm;Battery capacity conservation rate labeled as 2 is 79.2%, and thickness swelling is
0.28mm;Battery capacity conservation rate labeled as 3 is 84.5%, thickness swelling 0.26mm;Kept labeled as 4 battery capacity
Rate is 87.6%, thickness swelling 0.21mm;Battery capacity conservation rate labeled as 5 is 88.5%, thickness swelling 0.19mm,
Battery capacity conservation rate labeled as 6 is 89.1%, thickness swelling 0.17mm, and the battery capacity conservation rate labeled as 7 is
91.8%, thickness swelling amount is 0.15mm, and the battery capacity conservation rate labeled as 8 is 91.9%, and thickness swelling amount is 0.13mm,
Battery capacity conservation rate labeled as 9 is 92.1%, and thickness swelling amount is 0.11mm, and the battery capacity conservation rate labeled as 10 is
92.3%, thickness swelling amount is 0.10mm;In summary:Capability retention:(75.4+79.2+84.5+87.6+88.5+89.1+
91.8+91.9+92.1+92.3) % ÷ 10=87.2%, thickness swelling amount:(0.30+0.29+0.27+0.22+0.20+0.18+
0.16+0.14+0.12+0.11) mm=1.99mm.Compared with existing evaluating method, capability retention deviation 0.34%, thickness is swollen
Bulk deviation 1.02%.
The evaluating method of more above-mentioned comparative example and embodiment, see the table below 5.
Table 5:Comparative example and embodiment results contrast
Capability retention deviation refers to compare with the assessment method of existing (such as comparative example) with thickness swelling amount deviation.
As described above, can be preferably to realize the present invention.