CN102394315A - Cell characteristic vector based lithium ion cell configuration method - Google Patents

Abstract

The invention discloses a cell characteristic vector based lithium ion cell configuration method, which comprises the following steps of: carrying out one-time 0.2C discharge on cells to be configured, followed by 2C charge and discharge, finally standing for a while, recording the 2C discharge capacity C0.5, the ratio CI of constant voltage capacity to constant current capacity during the 2C charge, the ratio V0 of recovery voltage to discharge lower limit voltage after the final step of standing, and the correlation coefficient rYS of the characteristic vector formed by the 2C constant current charge and 2C constant current discharge voltage values of the cells and the standard characteristic vector, determining an appropriate grading numerical range for grading according to the C0.5, CI, V0 and Rys, and configuring individual cells within the specified range. The method provided by the invention is used to fully present the difference between cells and screen out cells with similar consistency for assembling and usage, thus raising the performance of battery packs.

Description

A kind of lithium ion battery grouping method based on the battery characteristics vector

Technical field

The present invention relates to the lithium ion battery combo, particularly a kind of lithium ion battery grouping method based on the battery characteristics vector.

Background technology

Along with the development of society, the application of lithium ion battery also more and more widely.In actual applications, often need tens of even hundreds of cells are fitted together by polyphone or parallel connection, to satisfy the demand of high voltage high power capacity.On the theory; Inconsistency between the cell is an absolute being; So in practical application, must through the combo Policy Filtering go out consistency relatively preferably cell carry out combo, assembling, just might make the overall performance of battery pack reach gratifying degree.

The method for group matching that generally adopts at present is: according to the capacity behind the cell partial volume, internal resistance, voltage, self discharge or the like, draft the parameter area of each group, in same scope, be classified as one grade, same shelves then can assemble use.The defective of this method is that these combo parameters can not fully reflect the difference between the battery, and after causing assembling use, the overall performance performance of battery pack is relatively poor.

Summary of the invention

To the deficiency that exists in the prior art; The object of the present invention is to provide a kind of lithium ion battery grouping method based on the battery characteristics vector that can fully reflect difference between the battery; After making that the battery assembling is used, the overall performance of battery pack is brought into play better.

Technical scheme of the present invention is achieved in that a kind of lithium ion battery grouping method based on the battery characteristics vector, comprises the steps:

(1) lithium ion battery that will treat combo discharges and recharges detection, and testing process is set to:

(1.1) with the electric current constant-current discharge of 0.2C to lower voltage limit,

(1.2) leave standstill 10～30 minutes,

(1.3) with the supreme pressure of rationing the power supply of the electric current constant current charge of 2C,

(1.4) charge to upper voltage limit after, constant voltage charge to electric current is less than 0.02C,

(1.5) leave standstill 10～30 minutes,

(1.6) with the electric current constant-current discharge of 2C to lower voltage limit,

(1.7) leave standstill 120～240 minutes;

(2) (1.3) step of record charging capacity C1 and (1.4) goes on foot charging capacity C2, calculates the ratio C I=C2/C1 of the two;

(3) (1.6) step of record discharge capacity C _0.5

(4) magnitude of voltage V1 after record (1.7) the step completion calculates the V0=V1/ lower voltage limit;

The voltage data in (5) collection (1.3), (1.6) step that is: is captured in the time interval T, waits the numerical value of lithium ion battery voltage that divides into groups, and is arranged in chronological order together, forms a vectorial Y (y ₁, y ₂... Y _n), the battery characteristics that is the monomer lithium ion battery of treating combo is vectorial; Each treats that the voltage data of combo lithium ion battery counts should be one by one correspondingly, promptly is synchronous on time shaft; According to formula (I), the similitude of counting cell characteristic vector and standard feature vector:

$r_{\mathrm{YS}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(y_i-\stackrel{\‾}{Y})(s_i-\stackrel{\‾}{S})}{\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(y_i-\stackrel{\‾}{Y})}\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(s_i-\stackrel{\‾}{S})}}$ Formula (I);

Wherein, y _iExpression wait the to divide into groups i dimension of lithium ion battery characteristics vector, i.e. i data points, n representes the dimension of vector, the i.e. number of cell voltage data point; Represent to wait to divide into groups the vectorial mean value of lithium ion battery characteristics; s _iThe i dimension of expression standard feature vector,

The mean value of expression standard feature vector; r _YSBattery characteristics vector and the coefficient correlation between the standard feature vector of the lithium ion battery of combo treated in expression; Need to prove: standard feature vector S (s ₁, s ₂... S _n) confirm according to creation data; Concrete confirm that method is following: in the lithium ion battery of same steady production batch; 500 lithium ion batteries of picked at random are gathered first " standard cell " voltage data in the 1.3rd, 1.6 steps as " standard cell " according to above-mentioned steps 1.1～1.7, are captured in the numerical value of first " standard cell " voltage in the time interval T that is:; And be arranged in chronological order together, form the vector of first " standard cell "

Be the battery characteristics vector of first " standard cell "; All the other " standard cells " are gathered after the same method, thereby obtain the battery characteristics vector of every " standard cell "

" i " expression i is " standard cell " only; The voltage data of 500 standard cells is counted should be corresponding one by one, promptly is synchronous on time shaft; Standard feature vector S (s ₁, s ₂... S _n) in $({\stackrel{1}{s}}_1+\·\·\·+{\stackrel{i}{s}}_1+\·\·\·+{\stackrel{500}{s}}_1)/500,$ $s_n=({\stackrel{1}{s}}_n+\·\·\·+{\stackrel{i}{s}}_n+\·\·\·+{\stackrel{500}{s}}_n)/500.$ In addition, " standard cell " number of elements of picked at random is The more the better, can make standard feature vector S (s like this ₁, s ₂... S _n) more accurate; If " standard cell " of picked at random is less than 100, standard feature vector S (s then ₁, s ₂... S _n) accuracy just poor, generally answer the batch process lithium ion battery of picked at random more than 100 as " standard cell ".

(6) according to C _0.5, CI, V0, r _YSValue is carried out stepping by the stepping number range, remaining combo lithium ion battery is sorted out, parameters all same stepping number range be one grade, the battery of same class then can combo uses.The stepping number range is the artificial number range of confirming, those skilled in the art can confirm according to actual needs, are that those skilled in the art can freely select; Use as long as guarantee the battery combo of same class, just can realize " the battery assembling uses the overall performance of back battery pack to be brought into play better ", the concrete numerical value of above-mentioned stepping number range does not influence the realization of the goal of the invention of the invention.

Above-mentioned lithium ion battery grouping method based on the battery characteristics vector, said lower voltage limit is 2.7V～3.0V for lithium manganate battery, ternary material battery or cobalt acid lithium battery; Said lower voltage limit is 2.0V～2.3V for ferric phosphate lithium cell.

Above-mentioned lithium ion battery grouping method based on the battery characteristics vector, said upper voltage limit is 4.1V～4.25V for lithium manganate battery, ternary material battery or cobalt acid lithium battery; Said upper voltage limit is 3.5～3.9V for ferric phosphate lithium cell.

Above-mentioned lithium ion battery grouping method based on the battery characteristics vector; Time interval T in (5) step is smaller or equal to 60S; Data collection point is more than or equal to 300; (1.3) data collection point equates that with (1.6) step data collection point quantity that is: (1.3) data collection point is more than or equal to 150, and (1.6) step data collection point is more than or equal to 150.

Above-mentioned lithium ion battery grouping method based on battery characteristics vector, the voltage data collection of each lithium ion battery of waiting to divide into groups is counted identical.

Above-mentioned lithium ion battery grouping method based on battery characteristics vector, the voltage data of each lithium ion battery of waiting to divide into groups o'clock according to the test in (1.3), (1.6) step successively is arranged in together in chronological order.

Above institute all carries out on lithium ion battery partial volume equipment in steps, data extract, analyze, be sorted on the corresponding DAS of tester on carry out.

The invention has the beneficial effects as follows: (1) the present invention is through CI value, C _0.5Value, V0 value, r _YSThe combo of value; The overall performance situation that can fully reflect cell capacity, internal polarization and battery charging and discharging; Fully characterized the difference between the battery, filtered out the close battery of consistency and assemble use, avoided the deficiency of general method for separating the sign ability of battery consistency; Improve the combo quality, made the performance of battery pack be improved.(2) combo required time of the present invention is short, the method for separating operation is directly perceived, simple, be easy to programming operations, is convenient to suitability for industrialized production.

Description of drawings

Fig. 1 is the (charging: CC, 5000mA constant current charge, cut-ff voltage 42V of battery pack loop test curve in the embodiment of the invention 1; CV, 42V constant voltage charge, cut-off current 200mA.Discharge: 5000mA constant-current discharge, cut-ff voltage 27V.Temperature: room temperature).

Embodiment

Present embodiment is chosen the IMP1865130 battery (nominal capacity 10Ah) that our company produces based on the lithium ion battery grouping method of battery characteristics vector, and production batch is 20110706; It comprises the steps:

1, the lithium ion battery that will treat combo is placed on the lithium ion battery program control test equipment and discharges and recharges detection, and testing process is set to:

1.1, constant-current discharge: constant current 2A, cut-ff voltage 2.7V,

1.2, leave standstill: time of repose 30 minutes,

1.3, constant current charge: constant current 20A, cut-ff voltage 4.2V,

1.4, constant voltage charge: constant voltage 4.2V, cut-off current 200mA,

1.5, leave standstill: time of repose 30 minutes,

1.6, constant-current discharge: constant current 20A, cut-ff voltage 2.7V,

1.7, leave standstill: time of repose 240 minutes;

2, the 1.3rd step of acquisition and recording constant current charge capacity C 1, the 1.4 goes on foot charging capacity C2 in corresponding testing software, calculates the ratio C I=C2/C1 of the two;

3, the 1.6th step of record discharge capacity C _0.5

4, magnitude of voltage V1 after record the 1.7th step completion calculates V0=V1/2.7;

5, in testing software, gather the voltage detailed data in the 1.3rd, 1.6 steps.Acquisition method is: since the 0th second of the 1.3rd step, write down the 1st data, whenever at a distance from voltage data of 10 seconds records, end to collecting 150 data points then; The above acquisition method of the 1.6th step repetition is also gathered 150 points; 300 data points that collect are arranged in a vector in chronological order, are designated as Y (y ₁, y ₂... Y _n), the battery characteristics that is the monomer lithium ion battery of treating combo is vectorial; Each treats that the voltage data of combo lithium ion battery counts should be one by one correspondingly, promptly is synchronous on time shaft.Simultaneously, according to creation data, the characteristic vector that settles the standard S (s ₁, s ₂... S _n); Concrete confirm that method is following: in the lithium ion battery of same steady production batch; 500 lithium ion batteries of picked at random are gathered first " standard cell " voltage data in the 1.3rd, 1.6 steps as " standard cell " according to above-mentioned steps 1.1～1.7, whenever gather the numerical value of first " standard cell " voltage at a distance from 10 seconds that is:; And be arranged in chronological order together, form the vector of first " standard cell "

Be the battery characteristics vector of first " standard cell "; All the other " standard cells " are gathered after the same method, thereby obtain the battery characteristics vector of every " standard cell "

" i " expression i is " standard cell " only; The voltage data of 500 standard cells is counted should be corresponding one by one, promptly is synchronous on time shaft; Standard feature vector S (s ₁, s ₂... S _n) in $s_1=({\stackrel{1}{s}}_1+\·\·\·+{\stackrel{i}{s}}_1+\·\·\·+{\stackrel{500}{s}}_1)/500,$ $s_n=({\stackrel{1}{s}}_n+\·\·\·+{\stackrel{i}{s}}_n+\·\·\·+{\stackrel{500}{s}}_n)/500.$ In addition, " standard cell " number of elements of picked at random is The more the better, can make standard feature vector S (s like this ₁, s ₂... S _n) more accurate; If " standard cell " of picked at random is less than 100, standard feature vector S (s then ₁, s ₂... S _n) accuracy just poor, generally answer the batch process lithium ion battery of picked at random more than 100 as " standard cell ".

According to following formula, calculate the battery characteristics vector and the vectorial coefficient correlation of standard feature of treating the combo lithium ion battery:

$r_{\mathrm{YS}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(y_i-\stackrel{\‾}{Y})(s_i-\stackrel{\‾}{S})}{\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(y_i-\stackrel{\‾}{Y})}\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(s_i-\stackrel{\‾}{S})}}$

Wherein, y _iThe i dimension of sorting battery characteristics vector is treated in expression, i.e. i data points, and n representes the dimension of vector, the i.e. number of cell voltage data point;

The mean value of sorting battery characteristics vector is treated in expression; s _iThe i dimension of expression standard feature vector,

The mean value of expression standard feature vector.r _YSThe characteristic vector of sorting battery and the coefficient correlation between the standard feature vector are treated in expression.

6, according to C _0.5, CI, V0, r _YSValue, carry out stepping by following stepping number range:

C _0.5≥9.2Ah；

CI 10％～15％，16％～20％，21％～25％，26％～30％；

V0?1.05～1.10 1.11～1.15，1.16～1.20；

r _YS?0.90～0.95，0.96～1.0；

Above-mentioned stepping number range is the artificial number range of confirming, those skilled in the art can confirm according to actual needs, are that those skilled in the art can freely select; As long as guaranteeing the battery combo of same class uses; Just can realize the goal of the invention of " the battery assembling uses the overall performance of back battery pack to be brought into play better ", that is: the concrete numerical value of above-mentioned stepping number range does not influence the realization of the goal of the invention of the invention.

In testing software, set corresponding stepping number range; Remaining combo lithium ion battery is sorted out, parameters all same stepping number range be one grade, utilize the LED lamp prompting machine down on the tester; Sub-category machine is down placed, and the battery of same class then can combo use.

Wherein, parameters is not participated in combo outside the above value scope, is defective item.

7, form a battery pack 36V10Ah battery pack according to selected following 10 batteries of the stepping scope in the 6th step, the combo data of monocell are (battery pack loop test curve is as shown in Figure 1):

The battery numbering	C 0.5	CI	V0	r YS
					002	9.28Ah	22％	1.18	0.98
006	9.26Ah	23％	1.17	0.99
					007	9.30Ah	22％	1.16	0.97
012	9.29Ah	24％	1.19	0.96
					013	9.32Ah	21％	1.19	0.97
015	9.27Ah	22％	1.18	0.96
					024	9.28Ah	23％	1.17	0.96
028	9.31Ah	22％	1.18	0.98
					032	9.31Ah	24％	1.18	0.98
033	9.30Ah	25％	1.17	0.97

Claims (6)

1. the lithium ion battery grouping method based on the battery characteristics vector is characterized in that, comprises the steps:

(1) lithium ion battery that will treat combo discharges and recharges detection, and testing process is set to:

(1.1) with the electric current constant-current discharge of 0.2C to lower voltage limit,

(1.2) leave standstill 10～30 minutes,

(1.3) with the supreme pressure of rationing the power supply of the electric current constant current charge of 2C,

(1.4) charge to upper voltage limit after, constant voltage charge to electric current is less than 0.02C,

(1.5) leave standstill 10～30 minutes,

(1.6) with the electric current constant-current discharge of 2C to lower voltage limit,

(1.7) leave standstill 120～240 minutes;

(2) (1.3) step of record charging capacity C1 and (1.4) goes on foot charging capacity C2, calculates the ratio C I=C2/C1 of the two;

(3) (1.6) step of record discharge capacity C _0.5

(4) magnitude of voltage V1 after record (1.7) the step completion calculates the V0=V1/ lower voltage limit;

The voltage data in (5) collection (1.3), (1.6) step that is: is captured in the time interval T, waits the numerical value of lithium ion battery voltage that divides into groups, and is arranged in chronological order together, forms a vectorial Y (y ₁, y ₂... Y _n), the battery characteristics that is the monomer lithium ion battery of treating combo is vectorial; Each treats that the voltage data of combo lithium ion battery counts should be one by one correspondingly, promptly is synchronous on time shaft; According to formula (I), the similitude of counting cell characteristic vector and standard feature vector:

$r_{\mathrm{YS}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(y_i-\stackrel{\‾}{Y})(s_i-\stackrel{\‾}{S})}{\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(y_i-\stackrel{\‾}{Y})}\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}(s_i-\stackrel{\‾}{S})}}$ Formula (I);

Wherein, y _iExpression wait the to divide into groups i dimension of lithium ion battery characteristics vector, i.e. i data points, n representes the dimension of vector, the i.e. number of cell voltage data point;

Represent to wait to divide into groups the vectorial mean value of lithium ion battery characteristics; s _iThe i dimension of expression standard feature vector, The mean value of expression standard feature vector; r _YSBattery characteristics vector and the coefficient correlation between the standard feature vector of the lithium ion battery of combo treated in expression;

(6) according to C _0.5, CI, V0, r _YSValue is carried out stepping by the stepping number range, remaining combo lithium ion battery is sorted out, parameters all same stepping number range be one grade, the battery of same class then can combo uses.

2. the lithium ion battery grouping method based on the battery characteristics vector according to claim 1 is characterized in that said lower voltage limit is 2.7V～3.0V for lithium manganate battery, ternary material battery or cobalt acid lithium battery; Said lower voltage limit is 2.0V～2.3V for ferric phosphate lithium cell.

3. the lithium ion battery grouping method based on the battery characteristics vector according to claim 1 is characterized in that said upper voltage limit is 4.1V～4.25V for lithium manganate battery, ternary material battery or cobalt acid lithium battery; Said upper voltage limit is 3.5～3.9V for ferric phosphate lithium cell.

4. the lithium ion battery grouping method based on the battery characteristics vector according to claim 1; It is characterized in that; Time interval T in (5) step is smaller or equal to 60S, and data collection point is more than or equal to 300, and (1.3) data collection point equates with (1.6) step data collection point quantity; That is: (1.3) data collection point is more than or equal to 150, and (1.6) step data collection point is more than or equal to 150.

5. the lithium ion battery grouping method based on battery characteristics vector according to claim 1 is characterized in that, the voltage data collection of each lithium ion battery of waiting to divide into groups is counted identical.

6. the lithium ion battery grouping method based on battery characteristics vector according to claim 1 is characterized in that, the voltage data of each lithium ion battery of waiting to divide into groups o'clock according to the test in (1.3), (1.6) step successively is arranged in together in chronological order.

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