阅读说明：本技术 电池容量的估测方法和装置、计算机可读存储介质和设备 (Method and apparatus for estimating battery capacity, computer-readable storage medium, and device ) 是由 冯旭东 杨树涛 梁铉正 张伟 李博 于 2020-03-31 设计创作，主要内容包括：本发明公开了一种电池容量的估测方法和装置、计算机可读存储介质和设备,其中估测方法包括步骤：获取多个测试电池的实际容量,并获取每个测试电池放电测试时的测试压差；对多个测试电池的实际容量和每个测试电池放电测试时的测试压差进行数据拟合以建立实际容量与测试压差之间的关系模型；获取待估测电池放电时的压差；根据待估测电池放电时的压差和实际容量与测试压差之间的关系模型计算待估测电池的容量。根据本发明实施例的估测方法的估测准确率更高。(The invention discloses an estimation method and device of battery capacity, a computer readable storage medium and equipment, wherein the estimation method comprises the following steps: acquiring actual capacities of a plurality of test batteries, and acquiring a test pressure difference of each test battery during discharge test; performing data fitting on the actual capacity of the plurality of test batteries and the test pressure difference of each test battery during discharge test to establish a relation model between the actual capacity and the test pressure difference; acquiring the voltage difference of the battery to be estimated during discharging; and calculating the capacity of the battery to be estimated according to the pressure difference of the battery to be estimated during discharging and a relation model between the actual capacity and the test pressure difference. The estimation method according to the embodiment of the invention has higher estimation accuracy.)

1. A method for estimating battery capacity, comprising the steps of:

acquiring actual capacities of a plurality of test batteries, and acquiring a test pressure difference of each test battery during discharge test;

carrying out data fitting on the actual capacity of a plurality of test batteries and the test pressure difference of each test battery during discharge test so as to establish a relation model between the actual capacity and the test pressure difference;

acquiring the voltage difference of the battery to be estimated during discharging;

and calculating the capacity of the battery to be estimated according to the voltage difference of the battery to be estimated during discharging and a relation model between the actual capacity and the test voltage difference.

2. The method according to claim 1, wherein the relational model is expressed by the following equation:

c1 ═ a △ V + b, C1 is the actual capacity, △ V is the test differential pressure, a, b are constants.

3. The method of estimating battery capacity according to claim 1 or 2, wherein obtaining the actual capacities of the plurality of test batteries comprises:

the actual capacity of each test cell was obtained by fully charging and fully discharging each test cell.

4. The method of claim 3, wherein the step of fully charging and fully discharging each test cell comprises:

carrying out constant current charging on each test battery to a preset upper limit voltage, and then carrying out constant voltage charging, and stopping charging until the charging current of the constant voltage charging reaches a preset cut-off current so as to fully charge each test battery;

and carrying out constant current discharge on the fully charged test battery until the voltage of the discharged test battery reaches a preset lower limit voltage.

5. A computer-readable storage medium, on which a battery capacity estimation program is stored, the battery capacity estimation program, when executed by a processor, implementing the battery capacity estimation method according to any one of claims 1 to 4.

6. A computer device comprising a memory, a processor and a battery capacity estimation program stored in the memory and executable on the processor, wherein the processor implements the battery capacity estimation method according to any one of claims 1 to 4 when executing the battery capacity estimation program.

7. An apparatus for estimating battery capacity, comprising:

the battery capacity acquisition module is used for acquiring the actual capacities of the plurality of test batteries;

the voltage difference acquisition module is used for acquiring the test voltage difference of each test battery during discharge test;

the fitting module is used for performing data fitting on the actual capacity of the plurality of test batteries and the test pressure difference during the discharge test of each test battery so as to establish a relation model between the actual capacity and the test pressure difference;

the voltage difference acquisition module is also used for acquiring the voltage difference of the battery to be estimated during discharging;

and the estimation module is used for calculating the capacity of the battery to be estimated according to the voltage difference of the battery to be estimated during discharging and a relation model between the actual capacity and the test voltage difference.

8. The battery capacity estimation apparatus according to claim 7, wherein the relational model is expressed by the following equation:

c1 ═ a △ V + b, C1 is the actual capacity, △ V is the test differential pressure, a, b are constants.

9. The battery capacity estimation apparatus according to claim 7 or 8, wherein the battery capacity acquisition module is further configured to obtain the actual capacity of each test battery by fully charging and fully discharging each test battery.

10. The battery capacity estimation apparatus according to claim 9, wherein when the battery capacity acquisition module obtains the actual capacity of each test battery, the battery capacity acquisition module performs constant current charging to a preset upper limit voltage for each test battery, and then performs constant voltage charging until the charging current of the constant voltage charging reaches a preset cutoff current, so that each test battery is fully charged, and then performs constant current discharging for the fully charged test battery until the voltage of the discharged test battery reaches a preset lower limit voltage.

Technical Field

The present invention relates to a method and an apparatus for estimating a battery capacity, a computer-readable storage medium, and a computer device.

Background

The lithium ion battery can be subjected to a capacity testing procedure before leaving a factory, namely, the battery is subjected to capacity grading. The capacity grading process is usually a process of full charge, full discharge and half charge of the battery, the whole process needs about 3-6 hours, the test time is long, the capacity is severely restricted, a manufacturer needs to purchase a large amount of high-precision capacity grading equipment to meet the requirement of capacity test, and the test cost is high.

Disclosure of Invention

The present application is based on the recognition and discovery by the inventors of the following facts:

the present inventors have known a method for estimating the capacity of a battery using the full capacity and the section capacity, and particularly, the prior art measures the full capacity and the section capacity of a plurality of batteries in a punctuation section, establishes a relationship model based on the full capacity and the section capacity, measures the section capacity of a target battery, and substitutes the relationship model based on the section capacity of the target battery to estimate the full capacity of the target battery. However, the accuracy of estimation using this prior art method is general, and the correlation R of the estimation result is general²About 0.86, with a variance within 0.8%.

Based on this, the inventors found that the correlation R of the results was estimated based on a relational model formed by fitting the full capacity of the battery and the differential pressure at the time of discharge test²The average error is only 0.34 percent as high as 0.949, the accuracy is further improved compared with that of an estimation model adopting interval capacity and full capacity, the prior art discloses a curve relation between voltage and capacity, but no discussion and mention is made on the relation between the voltage difference and the capacity, and the inventor breakthroughs in the method for fitting the voltage difference and the full capacity and establishing the relation model, so that the estimation result is closer to the real capacity.

The invention provides a method for estimating the battery capacity, which has better accuracy.

The invention also provides a computer readable storage medium.

The invention also provides computer equipment.

The invention also provides a device for estimating the battery capacity.

The method for estimating the battery capacity according to the embodiment of the invention comprises the following steps: acquiring actual capacities of a plurality of test batteries, and acquiring a test pressure difference of each test battery during discharge test; carrying out data fitting on the actual capacity of a plurality of test batteries and the test pressure difference of each test battery during discharge test so as to establish a relation model between the actual capacity and the test pressure difference; acquiring the voltage difference of the battery to be estimated during discharging; and calculating the capacity of the battery to be estimated according to the voltage difference of the battery to be estimated during discharging and a relation model between the actual capacity and the test voltage difference.

According to the method for estimating the battery capacity, disclosed by the embodiment of the invention, the relation model is formed by fitting the differential pressure and the actual capacity, so that compared with the prior art that fitting relation is carried out by using interval capacity and full capacity, the detection precision is greatly improved, the error rate is smaller, and the estimation result is closer to the real capacity.

In some embodiments, the relational model is expressed by the following formula:

c1 ═ a △ V + b, C1 is the actual capacity, △ V is the test differential pressure, a, b are constants.

In some embodiments, obtaining the actual capacity of the plurality of test cells comprises:

the actual capacity of each test cell was obtained by fully charging and fully discharging each test cell.

In some embodiments, fully charging and fully discharging each test cell comprises:

carrying out constant current charging on each test battery to a preset upper limit voltage, and then carrying out constant voltage charging, and stopping charging until the charging current of the constant voltage charging reaches a preset cut-off current so as to fully charge each test battery;

and carrying out constant current discharge on the fully charged test battery until the voltage of the discharged test battery reaches a preset lower limit voltage.

According to another embodiment of the present invention, a computer-readable storage medium stores thereon a battery capacity estimation program, which when executed by a processor implements the above-described battery capacity estimation method.

The computer device according to another embodiment of the present invention includes a memory, a processor, and a battery capacity estimation program stored in the memory and operable on the processor, and the processor implements the battery capacity estimation method as described above when executing the battery capacity estimation program.

The battery capacity estimation device according to the embodiment of the invention comprises: the battery capacity acquisition module is used for acquiring the actual capacities of the plurality of test batteries; the voltage difference acquisition module is used for acquiring the test voltage difference of each test battery during discharge test; the fitting module is used for performing data fitting on the actual capacity of the plurality of test batteries and the test pressure difference during the discharge test of each test battery so as to establish a relation model between the actual capacity and the test pressure difference; the voltage difference acquisition module is also used for acquiring the voltage difference of the battery to be estimated during discharging; and the estimation module is used for calculating the capacity of the battery to be estimated according to the voltage difference of the battery to be estimated during discharging and a relation model between the actual capacity and the test voltage difference.

In some embodiments, the relational model is expressed by the following formula:

c1 ═ a △ V + b, C1 is the actual capacity, △ V is the test differential pressure, a, b are constants.

In some embodiments, the battery capacity acquisition module is further configured to obtain the actual capacity of each test battery by fully charging and fully discharging each test battery.

In some embodiments, when the battery capacity obtaining module obtains the actual capacity of each test battery, the battery capacity obtaining module performs constant current charging on each test battery to a preset upper limit voltage, and then performs constant voltage charging until the charging current of the constant voltage charging reaches a preset cut-off current, so that each test battery is fully charged, and then performs constant current discharging on the fully charged test battery until the voltage of the discharged test battery reaches a preset lower limit voltage.

Drawings

FIG. 1 is a flow chart of an estimation method according to an embodiment of the invention;

FIG. 2 is a schematic diagram of an estimation apparatus according to an embodiment of the present invention;

FIG. 3 is a graph of a pressure differential versus capacity fit.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically connected, electrically connected or can communicate with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The present application is based on the recognition and discovery by the inventors of the following facts:

the present inventors have known a method of estimating battery capacity using full capacity and section capacity of a discharge section, and specifically, the prior art measures full capacity and section capacity of a plurality of batteries in a discharge section, creates a relationship model based on the full capacity and the section capacity, measures section capacity of a target battery, and substitutes the relationship model based on the section capacity of the target battery to estimate the full capacity of the target battery. However, the accuracy of estimation using this prior art method is general, and the correlation R of the estimation result is general²About 0.86, with a variance within 0.8%.

Based on this, the inventors found that the correlation R of the results was estimated based on a relational expression formed by fitting the full capacity of the battery and the differential pressure at the time of discharge test²The average error is only 0.34 percent up to 0.949, the accuracy is further improved compared with the accuracy of an estimation model adopting interval capacity and full capacity, and although the prior art discloses the curve relation of voltage and capacity, the prior art does not have any relation of pressure difference and capacityThe inventor breakthroughs and adopts the fitting of the pressure difference and the full capacity and establishes a relation model, so that the estimation result is closer to the real capacity.

The following describes a method for estimating battery capacity according to an embodiment of the present invention, the method including the steps of:

referring to fig. 1, S1, the actual capacities of the plurality of test cells are obtained, and the test differential pressure at the time of the discharge test of each test cell is obtained.

In step S1, the actual capacity of each test cell is obtained by fully charging and fully discharging each test cell, that is, by obtaining the actual capacity of the test cell through a conventional full charge and full discharge test, so that the data is more accurate,

the method further comprises the following steps of fully charging and fully discharging each test battery:

carrying out constant current charging on each test battery to a preset upper limit voltage, and then carrying out constant voltage charging, and stopping charging until the charging current of the constant voltage charging reaches a preset cut-off current so as to fully charge each test battery;

and carrying out constant current discharge on the fully charged test battery until the voltage of the discharged test battery reaches a preset lower limit voltage.

In some optional embodiments, the constant current charging and discharging current may be 0.5C to 1C, the upper limit voltage may be 4.2V or 4.35V, the lower limit voltage may be 2.8V or 3.0V, and the off current may be 0.05C.

In step S1, the test voltage difference obtained during the discharge test of each test cell may be the test voltage difference of any time period in the test process, for example, the voltage V1 at the beginning of the discharge test and the voltage V2 discharged for a certain time may be selected, and then the voltage difference △ V is V1-V2, optionally, the time of discharge here is preferably 10-50min, and the fitting is performed by using the voltage difference at the initial stage of the discharge test and the actual capacity, so that the fitting model is more accurate.

And S2, performing data fitting on the actual capacities of the plurality of test batteries and the test pressure difference of each test battery during discharge test to establish a relation model between the actual capacities and the test pressure difference, wherein the relation model is expressed by the following formula, namely a △ V + b is C1, the actual capacities are C1, the test pressure difference is △ V, and a and b are constants.

And S3, acquiring the voltage difference when the battery to be estimated is discharged. In the step, the batteries to be estimated are selected according to the same model and specification, and the batteries to be estimated are fully charged and then discharged for a certain time, so that the voltage difference of the batteries to be estimated is obtained, the batteries to be estimated are not subjected to full-charge discharge process testing any more, the aim of predicting the capacity is fulfilled, and the testing time is greatly shortened.

And S4, calculating the capacity of the battery to be estimated according to the voltage difference when the battery to be estimated is discharged and a relation model between the actual capacity and the test voltage difference.

Specific examples are as follows:

the measured capacity of the example is 1C charge, the upper limit voltage is 4.2V, the cut-off current is 0.05C, the discharge current is 1C, the lower limit voltage is 2.8V, the recording capacity of the end of discharge is C1, the voltage difference before and after 30min of discharge is △ V, and the measured capacity is C1, and the detailed data and the fitting relation are as follows:

through the fitting of measured data, the relation C1 between C1 and △ V is-138.52 △ V +127118, and the correlation R2 reaches 0.949, so that the correlation is strong.

The estimated capacity C2 was obtained by substituting △ V obtained when the 48pcs battery was discharged for 30min into the relational expression, which is shown in table 1.

As can be seen from Table 1, the maximum error of the predicted capacity is 0.97% compared with the actually measured capacity, and the average error is only 0.34%, so that the method is relatively accurate. Compared with the traditional full filling and discharging test, the method has the advantages that the flow time can be shortened by more than half, the production efficiency is greatly improved, and the production cost is saved.

TABLE 1 measured and predicted Capacity

Serial number	△V(mv)	Measured capacity (mAh)	Predicted Capacity (mAh)	Percentage of error
					1	550.2	50859.53	50904.3	-0.09％
2	548.7	51383.7	51112.08	0.53％
					3	548.5	51638.72	51139.78	0.97％
4	548.1	51312.87	51195.19	0.23％
					5	546.1	51822.89	51472.23	0.68％
6	546.9	51227.87	51361.41	-0.26％
					7	549.5	50930.37	51001.26	-0.14％
8	555.1	50434.52	50225.55	0.41％
					9	555.7	50491.19	50142.44	0.69％
10	553	50193.67	50516.44	-0.64％
					11	554.1	50052.01	50364.07	-0.62％
12	554.9	50434.52	50253.25	0.36％
					13	554.8	49995.34	50267.1	-0.54％
14	552.1	50264.52	50641.11	-0.75％
					15	552.6	50788.7	50571.85	0.43％
16	555	50108.68	50239.4	-0.26％
					17	555.6	50023.68	50156.29	-0.27％
18	552.5	50392.32	50585.7	-0.38％
					19	551.7	50455.45	50696.52	-0.48％
20	546.6	51638.72	51402.97	0.46％
					21	547	51355.37	51347.56	0.02％
22	545.3	51610.38	51583.04	0.05％
					23	545	51567.88	51624.6	-0.11％
24	546.4	51298.71	51430.67	-0.26％
					25	545.9	51426.21	51499.93	-0.14％
26	544.4	51541.59	51707.71	-0.32％
					27	548.2	51015.37	51181.34	-0.33％
28	548	51199.54	51209.04	-0.02％
					29	548.3	51511.16	51167.48	0.67％
30	545.3	51808.72	51583.04	0.44％
					31	542.4	52189.32	51984.75	0.39％
32	542.9	51853.2	51915.49	-0.12％
					33	542.3	51888.65	51998.6	-0.21％
34	540.6	52056.32	52234.09	-0.34％
					35	540.2	52365.86	52289.5	0.15％
36	538.3	52800.41	52552.68	0.47％
					37	536.7	52616.24	52774.32	-0.30％
38	538.2	52672.91	52566.54	0.20％
					39	538.1	52276.23	52580.39	-0.58％
40	538.7	52545.4	52497.28	0.09％
					41	537.8	52842.91	52621.94	0.42％
42	536.6	52814.58	52788.17	0.05％
					43	538	52658.74	52594.24	0.12％
44	533.9	52998.75	53162.17	-0.31％
					45	535	52786.24	53009.8	-0.42％
46	537.6	52786.24	52649.65	0.26％
					47	537.4	52630.41	52677.35	-0.09％
48	536.6	52616.24	52788.17	-0.33％

In summary, according to the method for estimating battery capacity of the embodiment of the invention, the relationship model is formed by fitting the differential pressure and the actual capacity, so that compared with the prior art in which fitting relationship is performed by using the interval capacity and the full capacity, the detection precision is greatly improved, the error rate is smaller, and the estimation result is closer to the actual capacity.

According to another embodiment of the present invention, a computer-readable storage medium stores thereon a battery capacity estimation program, which when executed by a processor implements the battery capacity estimation method described in the above embodiments.

According to another embodiment of the present invention, a computer device includes a memory, a processor, and a battery capacity estimation program stored in the memory and executable on the processor, wherein the processor implements the battery capacity estimation method described in the above embodiments when executing the battery capacity estimation program.

According to the battery capacity estimation apparatus 100 of the further embodiment of the present invention, as shown in fig. 2, the battery capacity estimation apparatus 100 includes a battery capacity obtaining module 10, a voltage difference obtaining module 20, a fitting module 30 and an estimation module 40, the battery capacity obtaining module 10 is configured to obtain actual capacities of a plurality of test batteries, the voltage difference obtaining module 20 is configured to obtain a test voltage difference during a discharge test of each test battery, the fitting module 30 is configured to perform data fitting on the actual capacities of the plurality of test batteries and the test voltage difference during the discharge test of each test battery to establish a relation model between the actual capacities and the test voltage difference, the relation model is expressed by the following formula, wherein C1 is a △ V + b, C1 is the actual capacities, △ V is the test voltage difference, and a and b are constants.

In some embodiments, the battery capacity acquisition module 10 is further configured to obtain the actual capacity of each test battery by fully charging and fully discharging each test battery.

In some embodiments, when the battery capacity obtaining module 10 obtains the actual capacity of each test battery, the constant current charging is performed on each test battery to a preset upper limit voltage, and then the constant voltage charging is performed until the charging current of the constant voltage charging reaches a preset cut-off current, so that each test battery is fully charged, and then the constant current discharging is performed on the fully charged test battery until the voltage of the discharged test battery reaches a preset lower limit voltage.

It should be noted that, for the estimation apparatus 100 of battery capacity, the steps executed by the above-mentioned components correspond to the steps in the estimation method embodiment one by one, and the specific implementation can refer to the description in the method embodiment.

According to the battery capacity estimation device 100 of the embodiment of the invention, the relation model is formed by fitting the differential pressure and the actual capacity, so that compared with the prior art that fitting relation is carried out by using interval capacity and full capacity, the detection precision is greatly improved, the error rate is smaller, and the estimation result is closer to the real capacity.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.