CN117538776A - Battery cycle life prediction method and device, storage medium and electronic equipment - Google Patents
Battery cycle life prediction method and device, storage medium and electronic equipment Download PDFInfo
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- CN117538776A CN117538776A CN202311775514.XA CN202311775514A CN117538776A CN 117538776 A CN117538776 A CN 117538776A CN 202311775514 A CN202311775514 A CN 202311775514A CN 117538776 A CN117538776 A CN 117538776A
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- 238000000034 method Methods 0.000 title claims abstract description 46
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 230
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 229
- 230000022131 cell cycle Effects 0.000 claims abstract description 98
- 238000007599 discharging Methods 0.000 claims description 21
- 238000004891 communication Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 3
- 230000008569 process Effects 0.000 description 11
- 239000000463 material Substances 0.000 description 8
- 229910001416 lithium ion Inorganic materials 0.000 description 7
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 6
- 238000004146 energy storage Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 239000003792 electrolyte Substances 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000001351 cycling effect Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000006138 lithiation reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- NCZYUKGXRHBAHE-UHFFFAOYSA-K [Li+].P(=O)([O-])([O-])[O-].[Fe+2].[Li+] Chemical compound [Li+].P(=O)([O-])([O-])[O-].[Fe+2].[Li+] NCZYUKGXRHBAHE-UHFFFAOYSA-K 0.000 description 1
- BVDKLOSQZNHXSI-UHFFFAOYSA-N [Si].[Ni].[C] Chemical compound [Si].[Ni].[C] BVDKLOSQZNHXSI-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 230000034964 establishment of cell polarity Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/385—Arrangements for measuring battery or accumulator variables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/367—Software therefor, e.g. for battery testing using modelling or look-up tables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/378—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Secondary Cells (AREA)
Abstract
The invention discloses a battery cycle life prediction method, a device, a storage medium and electronic equipment, which can perform primary battery cell cycle on a battery which is pre-lithiated and obtain corresponding first discharge capacity, wherein the battery cell cycle is never performed on the battery which is pre-lithiated before the primary battery cell cycle is performed on the battery which is pre-lithiated; performing N times of battery cell cycles on the battery with the pre-lithium, and obtaining a second discharge capacity corresponding to the battery cell cycle with the N th time, wherein the battery cell cycle with the N th time is counted from the first battery cell cycle; and determining the battery cycle times of the battery with the pre-lithium according to the first discharge capacity and the second discharge capacity. Therefore, the invention can accurately predict the battery cycle times of the battery based on the discharge capacity of the battery which is pre-lithiated, and has accurate prediction result and good effect.
Description
Technical Field
The present invention relates to the field of energy storage, and in particular, to a method and apparatus for predicting battery cycle life, a storage medium, and an electronic device.
Background
With the vigorous development of the automobile and energy storage industry, the service life requirements of lithium ion power batteries and energy storage batteries are higher and higher, and the battery is pre-lithiated, so that the method is an effective method for prolonging the cycle life of the lithium ion battery, but the cycle number prediction of the battery after pre-lithiation is not good. Therefore, how to accurately predict the cycle number of the battery after the pre-lithium is a technical problem to be solved by those skilled in the art.
Disclosure of Invention
In view of the above, the present invention provides a battery cycle life prediction method, apparatus, storage medium, and electronic device that overcome or at least partially solve the above problems.
In a first aspect, a battery cycle life prediction method includes:
performing a first battery cell cycle on the pre-lithium battery and obtaining a corresponding first discharge capacity, wherein the pre-lithium battery never performs the battery cell cycle before performing the first battery cell cycle on the pre-lithium battery;
performing N times of battery cell cycles on the battery with the pre-lithium, and obtaining a second discharge capacity corresponding to the battery cell cycle with the N th time, wherein the battery cell cycle with the N th time is counted from the first battery cell cycle;
and determining the battery cycle times of the battery with the pre-lithium according to the first discharge capacity and the second discharge capacity.
Optionally, in some optional embodiments, the performing a first cell cycle on the pre-lithiated battery and obtaining a corresponding first discharge capacity includes:
fully charging the battery with the pre-lithium according to a preset standard multiplying power;
discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery drops to a preset cut-off voltage;
when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to a first preset cut-off current;
and when the current of the pre-lithium battery drops to the first preset cut-off current, obtaining the capacity of the pre-lithium battery discharged during the constant voltage discharge as the first discharge capacity.
Optionally, in some optional embodiments, the performing N times of the cell cycles on the pre-lithium battery and obtaining the second discharge capacity corresponding to performing the nth cell cycle includes:
and performing the battery cell cycle on the battery with the pre-lithium for N times, wherein each time the battery cell cycle is performed: fully charging the pre-lithium battery with the preset standard multiplying power; discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery drops to the preset cut-off voltage; when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to the first preset cut-off current;
and after carrying out an Nth battery cell cycle on the pre-lithium battery, obtaining the capacity of the pre-lithium battery discharged during constant voltage discharge of the Nth battery cell cycle as the second discharge capacity.
Optionally, in some optional embodiments, the determining the number of battery cycles of the pre-lithiated battery according to the first discharge capacity and the second discharge capacity includes:
according to formula 1: and calculating to obtain the battery cycle times of the battery subjected to pre-lithium, wherein the cycle is the battery cycle times, Q is the preset pre-lithium amount of the battery subjected to pre-lithium, eta is the pre-lithium efficiency of the battery subjected to pre-lithium, and C1 is the first discharge capacity and C2 is the second discharge capacity.
Optionally, in certain optional embodiments, before the determining the number of battery cycles of the pre-lithiated battery according to the first discharge capacity and the second discharge capacity, the method further comprises:
and performing a first cell cycle on the battery without pre-lithium, and obtaining a corresponding third discharge capacity, wherein the battery without pre-lithium never performs the cell cycle before performing the first cell cycle on the battery without pre-lithium.
Optionally, in some optional embodiments, the performing a first cell cycle on the battery without pre-lithium and obtaining a corresponding third discharge capacity includes:
fully charging the battery without pre-lithium according to the preset standard multiplying power;
discharging the battery without pre-lithium with the preset standard multiplying power after the battery without pre-lithium is fully charged until the voltage of the battery without pre-lithium drops to a preset cut-off voltage;
after the voltage of the battery without pre-lithium is reduced to the preset cut-off voltage, maintaining the voltage of the battery without pre-lithium to be the preset cut-off voltage, and performing constant voltage discharge on the battery without pre-lithium until the current of the battery without pre-lithium is reduced to the first preset cut-off current;
and when the current of the battery without pre-lithium drops to the first preset cut-off current, obtaining the capacity of the battery without pre-lithium discharged during the constant voltage discharge as the third discharge capacity.
Optionally, in some optional embodiments, the determining the number of battery cycles of the pre-lithiated battery according to the first discharge capacity and the second discharge capacity includes:
according to equation 2: and calculating the battery cycle times of the pre-lithium battery, wherein the cycles are the battery cycle times, the C1 is the first discharge capacity, the C2 is the second discharge capacity and the C3 is the third discharge capacity.
In a second aspect, a battery cycle life prediction apparatus includes: a first capacity obtaining unit, a second capacity obtaining unit, and a cycle number determining unit;
the first capacity obtaining unit is used for performing a first battery cell cycle on the battery which is pre-lithiated, and obtaining a corresponding first discharge capacity, wherein the battery which is pre-lithiated never performs the battery cell cycle before the battery cell cycle is performed for the first time on the battery which is pre-lithiated;
the second capacity obtaining unit is configured to perform N times of the cell cycles on the battery that has been pre-lithiated, and obtain a second discharge capacity corresponding to an nth cell cycle, where the nth cell cycle starts counting from the first cell cycle;
the cycle number determining unit is used for determining the battery cycle number of the battery with pre-lithium according to the first discharge capacity and the second discharge capacity.
In a third aspect, a computer-readable storage medium has stored thereon a program that, when executed by a processor, implements the battery cycle life prediction method of any one of the above.
In a fourth aspect, an electronic device includes at least one processor, at least one memory coupled to the processor, and a bus; the processor and the memory complete communication with each other through the bus; the processor is configured to invoke program instructions in the memory to perform the battery cycle life prediction method of any of the above.
By means of the technical scheme, the battery cycle life prediction method, the battery cycle life prediction device, the storage medium and the electronic equipment can conduct first battery core cycle on the battery subjected to pre-lithium and obtain corresponding first discharge capacity, wherein the battery subjected to pre-lithium never conducts battery core cycle before conducting the first battery core cycle on the battery subjected to pre-lithium; performing N times of battery cell cycles on the battery with the pre-lithium, and obtaining a second discharge capacity corresponding to the battery cell cycle with the N th time, wherein the battery cell cycle with the N th time is counted from the first battery cell cycle; and determining the battery cycle times of the battery with the pre-lithium according to the first discharge capacity and the second discharge capacity. Therefore, the invention can accurately predict the battery cycle times of the battery based on the discharge capacity of the battery which is pre-lithiated, and has accurate prediction result and good effect.
The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present invention more readily apparent.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:
FIG. 1 shows a flow chart of a battery cycle life prediction method provided by the invention;
FIG. 2 is a schematic diagram of a cell cycling process provided by the present invention;
fig. 3 is a schematic diagram showing the structure of a battery cycle life prediction apparatus according to the present invention;
fig. 4 shows a schematic structural diagram of an electronic device provided by the invention.
Detailed Description
With the vigorous development of the automobile and energy storage industry, the service life requirements of lithium ion power batteries and energy storage batteries are higher and higher, and the battery is pre-lithiated, so that the method is an effective method for prolonging the cycle life of the lithium ion battery, but the cycle number prediction of the battery after pre-lithiation is not good. Pre-lithium refers to adding lithium to the interior of a lithium ion battery to replenish lithium ions prior to operation of the battery. Lithium is supplemented to the electrode material through pre-lithium, so that irreversible lithium loss caused by formation of an SEI film is counteracted, and the total capacity and energy density of the battery are improved. And an SEI film is formed on the surface of the negative electrode in the first charging process of the battery cell, so that active lithium is consumed, and the consumed active lithium is supplemented in a pre-lithium mode, so that gram capacity exertion and cycle performance of the battery cell are improved.
When the battery cell is designed, factors such as process tolerance, no lithium precipitation during charging and the like are considered, the CB value (the capacity of the negative electrode in unit area or the capacity of the positive electrode in unit area) of the battery cell is set to be more than 1 and is generally about 1.1, and lithium can be intercalated into the residual negative electrode main material which is not fully charged through pre-lithium, so that the active lithium storage capacity of the negative electrode plate is further improved.
Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
As shown in fig. 1, the present invention provides a battery cycle life prediction method, comprising: s100, S200, and S300;
s100, performing primary battery core circulation on the battery with the pre-lithium, and obtaining a corresponding first discharge capacity;
wherein the pre-lithium battery has never been subjected to a cell cycle before the first cell cycle is performed on the pre-lithium battery;
alternatively, the pre-lithium battery in S100 may be understood as: a battery that has completed pre-lithium but has not yet been charged. Thus, in S100, the present invention may perform a first cell cycle on the battery. It should be noted that: cell cycling refers to the complete process of charging and discharging a battery.
For example, in some alternative embodiments, the S100 includes: step 1.1, step 1.2, step 1.3 and step 1.4;
step 1.1, fully charging the battery with the pre-lithium according to a preset standard multiplying power;
optionally, different battery core products and different standard multiplying power can be specifically set according to actual products, and the invention is not limited to this. It should be noted that: when the battery is subjected to cell cycle, the standard multiplying power used in the charging process and the discharging process is the same.
Optionally, fully charging the pre-lithium battery means: the battery with pre-lithium is fully charged. That is, the present invention can continuously monitor the state of charge of the battery while charging the battery to ensure that the battery is charged, which is not described in detail.
Step 1.2, discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery is reduced to a preset cut-off voltage;
alternatively, different cell products have different cut-off voltages, and may be specifically set according to actual products, which is not limited in the present invention. It should be noted that: in the process of discharging the battery, the invention can continuously monitor the voltage state of the battery, and when the voltage drops to the preset cut-off voltage, the discharging is stopped at first so as to be convenient for switching to the discharging mode of the step 1.3.
Step 1.3, when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be unchanged at the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to a first preset cut-off current;
optionally, when the voltage drops to the preset cut-off voltage, the present invention may switch to step 1.3. That is, the battery is continuously discharged in a constant voltage manner, and the current state of the battery is continuously monitored until the current drops to a first preset cut-off current, which is not limited by the present invention.
Alternatively, the voltage of the battery is continuously maintained at a preset cutoff voltage during the constant voltage discharge. The capacity of the battery cell polarization is released through a constant voltage discharge mode, one part of active lithium after pre-lithium is stored in a residual lithium vacancy of the positive electrode, and the residual active lithium is stored in the positive electrode in a lithium-rich state and a pseudo-capacitor mode.
Alternatively, the first preset off current is not particularly limited, and may be set to a suitable value according to actual needs. For example, the first preset off-current of the present invention may be equal to 0.04C. "C" herein refers to the nominal capacity, and refers to the capacity of the battery at the time of shipment; for example: nominal capacity = 100Ah; off-current=0.04 c=0.04×100=4a, to which the present invention is not limited.
And step 1.4, when the current of the battery with the pre-lithium drops to the first preset cut-off current, obtaining the capacity of the battery with the pre-lithium discharged during the constant voltage discharge as the first discharge capacity.
Alternatively, as described above, the constant voltage discharge is switched from the voltage of the battery to the preset cutoff voltage. The invention can collect the capacity of the battery in the constant voltage discharge period as the first discharge capacity, and the invention is not limited to this.
S200, carrying out N times of battery cell circulation on the battery with the pre-lithium, and obtaining a second discharge capacity corresponding to the Nth battery cell circulation;
wherein the nth cell cycle counts from the first cell cycle;
alternatively, as described above, each cell cycle can be broadly divided into: full charge at a preset standard multiplying power, discharge at a preset standard multiplying power, and constant voltage discharge. In order to accurately predict the active lithium lost per cell cycle, it is predicted how many cell cycles the pre-lithiated battery can perform. The invention can collect the corresponding second discharge capacity after carrying out N times of cell cycles on the battery. It should be noted that: the invention does not limit N specifically, and can be set according to actual needs. In general, the smaller the value of N, the earlier the cycle life of the battery cell can be predicted under the condition of ensuring the accuracy; the larger the N value is, the more the influence of factors such as test errors and activation of the battery core on the battery life prediction can be reduced. The value range of N can be: n is more than or equal to 50 and less than or equal to 200.
For example, in some alternative embodiments, the S200 includes: step 2.1 and step 2.2;
step 2.1, performing N times of the cell cycle on the pre-lithium battery, wherein each time the cell cycle is performed: fully charging the pre-lithium battery with the preset standard multiplying power; discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery drops to the preset cut-off voltage; when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to the first preset cut-off current;
and 2.2, after carrying out the Nth battery cell cycle on the pre-lithium battery, obtaining the capacity of the pre-lithium battery discharged during the constant voltage discharge of the Nth battery cell cycle as the second discharge capacity.
Alternatively, the invention can start counting from the first cell cycle when counting N. For example, if N is equal to 100, it means that the pre-lithiated battery is subjected to 100 battery cell cycles, including the first battery cell cycle and 99 battery cell cycles after the first battery cell cycle, which the present invention is not limited to.
And S300, determining the battery cycle times of the battery with the pre-lithium according to the first discharge capacity and the second discharge capacity.
Alternatively, the number of battery cycles referred to in the present invention can be understood as: the battery has a theoretical battery cycle life. That is, the battery may be cyclically charged and discharged for a plurality of times, and the present invention is not limited thereto.
Optionally, the process of determining the cycle number of the battery is not particularly limited, and the battery cycle number can be set according to actual needs.
For example, in some alternative embodiments, the S300 includes:
according to formula 1: and calculating to obtain the battery cycle times of the battery subjected to pre-lithium, wherein the cycle is the battery cycle times, Q is the preset pre-lithium amount of the battery subjected to pre-lithium, eta is the pre-lithium efficiency of the battery subjected to pre-lithium, and C1 is the first discharge capacity and C2 is the second discharge capacity.
Alternatively, the preset amount of pre-lithium of the pre-lithium battery may be directly obtained after pre-lithium of the battery, and the pre-lithium efficiency may be also a theoretical value, N being explained in S200 above.
Optionally, in some optional embodiments, before the step S300, the method further includes: step 3.1;
and 3.1, performing a first battery cell cycle on the battery without pre-lithium, and obtaining a corresponding third discharge capacity, wherein the battery without pre-lithium never performs the battery cell cycle before performing the first battery cell cycle on the battery without pre-lithium.
Alternatively, a battery without pre-lithium refers to: the battery which has not been pre-lithiated, i.e., the negative electrode host material of the battery has not been intercalated with lithium, is not limited in this regard.
Optionally, the non-pre-lithium battery in step 3.1 is also a battery that has not been charged yet, and the present invention may perform a first cell cycle to determine the corresponding lithium loss of the non-pre-lithium battery during the first cell cycle.
For example, in certain alternative embodiments, the step 3.1 includes: step 4.1, do not do 4.2, step 4.3 and step 4.4;
step 4.1, fully charging the battery without pre-lithium with the preset standard multiplying power;
optionally, for the step 4.1, please refer to the aforementioned step 1.1 for equivalent understanding, which is not described in detail in the present disclosure.
Step 4.2, discharging the battery without pre-lithium with the preset standard multiplying power after the battery without pre-lithium is fully charged until the voltage of the battery without pre-lithium is reduced to a preset cut-off voltage;
optionally, for step 4.2, please refer to the foregoing step 1.2 for equivalent understanding, which is not described in detail herein.
Step 4.3, after the voltage of the non-pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the non-pre-lithium battery to be unchanged at the preset cut-off voltage, and performing constant voltage discharge on the non-pre-lithium battery until the current of the non-pre-lithium battery is reduced to the first preset cut-off current;
optionally, for step 4.3, please refer to the foregoing step 1.3 for equivalent understanding, which is not described in detail herein.
And 4.4, when the current of the battery without pre-lithium drops to the first preset cut-off current, obtaining the capacity of the battery without pre-lithium discharged during the constant voltage discharge as the third discharge capacity.
Optionally, for step 4.4, please refer to the foregoing step 1.4 for equivalent understanding, which is not described in detail herein.
Optionally, based on the example including step 4.1, not 4.2, step 4.3, and step 4.4, in some optional embodiments, the step S300 includes:
according to equation 2: and calculating the battery cycle times of the pre-lithium battery, wherein the cycles are the battery cycle times, the C1 is the first discharge capacity, the C2 is the second discharge capacity and the C3 is the third discharge capacity.
It should be noted that: the number of battery cycles calculated based on the above equation 1 or equation 2 can be understood as: predicting the cycle life of the obtained horizontal segment. During the cell cycle, it can be divided into horizontal and inclined sections, as will be understood with particular reference to fig. 2.
Optionally, in order to further clearly illustrate the present invention, specific examples are provided below to illustrate the aspects and effects of the present invention.
The pre-lithium mode of the lithium iron phosphate lithium ion battery core can be one or more of positive electrode pre-lithium, negative electrode pre-lithium, electrochemical pre-lithium and chemical pre-lithium.
As shown in table 1, in examples 1 to 8, specific parameters:
the lithium pre-forming mode is lithium powder pre-forming;
the main material of the positive electrode adopts lithium iron phosphate (LPF), and the formula of the positive electrode comprises lithium iron phosphate: SP: pvdf=97%: 1%:2%;
the main material of the negative electrode adopts graphite, and the formula of the embodiment is graphite: SP: CMC: SBR:96.7%:1%:0.8%:1.5%;
the CB value of the battery cell is 1.12;
the electrolyte adopts commercial lithium iron phosphate electrolyte;
the diaphragm adopts a PP diaphragm with the thickness of 14 microns.
As shown in table 1, in examples 9 to 13, specific parameters:
the lithium pre-forming mode is lithium powder pre-forming;
the positive electrode main material adopts NCM, and the formula is: NCM811: SP: CNTs: pvdf=97.8%: 0.8%:0.5%:0.9%.
The cathode main material is used for a graphite and silica composite material, and the main material proportion is graphite: silicon = 8:2; the formula of the pole piece is as follows: main material: SP: CNTS: PAA: sbr=95%: 1.5%:0.1%:1.1%:2.2%;
the CB value of the battery cell is 1.08;
the electrolyte adopts commercial electrolyte suitable for high nickel silicon carbon;
the diaphragm adopts a PE diaphragm, and the thickness of the diaphragm is 9 micrometers.
The test mode is as follows:
the cyclic manner of all 2 examples includes charging: 1C is charged to the upper limit voltage at a constant voltage, and the cut-off current is 0.05C; discharging: and discharging the 1C constant current to the lower limit voltage. The cycle life of the different pre-lithium amounts is compared in table 1 below.
TABLE 1
Based on the above table 1, it can be seen that different amounts of pre-lithium will affect the predicted service life of the battery and the actual service life of the battery. According to the invention, the corresponding pre-lithium amount of different battery cell products can be determined according to continuous tests and experiments, so as to ensure the accuracy of the prediction result. Meanwhile, the method can quickly obtain the prediction result in a short period by reducing the cycle times N, and has quick response.
As shown in fig. 3, the present invention provides a battery cycle life prediction apparatus comprising: a first capacity obtaining unit 100, a second capacity obtaining unit 200, and a cycle number determining unit 300;
the first capacity obtaining unit 100 is configured to perform a first battery cell cycle on a battery that has been pre-lithiated, and obtain a corresponding first discharge capacity, where the battery that has been pre-lithiated has never been subjected to the battery cell cycle before the battery cell cycle is performed for the first time on the battery that has been pre-lithiated;
the second capacity obtaining unit 200 is configured to perform N times of the cell cycles on the battery that has been pre-lithiated, and obtain a second discharge capacity corresponding to an nth cell cycle, where the nth cell cycle starts counting from the first cell cycle;
the cycle number determining unit 300 is configured to determine a battery cycle number of the battery that has been pre-lithiated according to the first discharge capacity and the second discharge capacity.
Optionally, in some optional embodiments, the first capacity obtaining unit 100 includes: a first charging subunit, a first discharging subunit, a first constant voltage subunit, and a first obtaining subunit;
the first charging subunit is used for fully charging the battery with the pre-lithium at a preset standard multiplying power;
the first discharging subunit is configured to discharge the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged, until the voltage of the pre-lithium battery drops to a preset cut-off voltage;
the first constant voltage subunit is configured to, when the voltage of the pre-lithium battery drops to the preset cutoff voltage, maintain the voltage of the pre-lithium battery unchanged at the preset cutoff voltage, perform constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery drops to a first preset cutoff current;
the first obtaining subunit is configured to obtain, as the first discharge capacity, a capacity of the pre-lithium battery that is discharged during the constant voltage discharge when the current of the pre-lithium battery decreases to the first preset cutoff current.
Optionally, in some optional embodiments, the second capacity obtaining unit 200 includes: a circulation subunit and a second acquisition subunit;
the cycle subunit is configured to perform N times of the cell cycle on the pre-lithiated battery, where each time the cell cycle is performed: fully charging the pre-lithium battery with the preset standard multiplying power; discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery drops to the preset cut-off voltage; when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to the first preset cut-off current;
and the second obtaining subunit is configured to obtain, after performing an nth cell cycle on the pre-lithium battery, a capacity of the pre-lithium battery that is discharged during constant voltage discharge of the nth cell cycle as the second discharge capacity.
Optionally, in some optional embodiments, the cycle number determining unit 300 includes: a first time number determination subunit;
the first time number determining subunit is configured to: and calculating to obtain the battery cycle times of the battery subjected to pre-lithium, wherein the cycle is the battery cycle times, Q is the preset pre-lithium amount of the battery subjected to pre-lithium, eta is the pre-lithium efficiency of the battery subjected to pre-lithium, and C1 is the first discharge capacity and C2 is the second discharge capacity.
Optionally, in some optional embodiments, the apparatus further comprises: a third capacity obtaining unit;
the third capacity obtaining unit is configured to perform a first cell cycle on a battery that is not pre-lithium before the number of battery cycles of the battery that is pre-lithium is determined according to the first discharge capacity and the second discharge capacity, and obtain a corresponding third discharge capacity, where the battery that is not pre-lithium has never been subjected to the cell cycle before the first cell cycle is performed on the battery that is not pre-lithium.
Optionally, in some optional embodiments, the third capacity obtaining unit includes: a second charging subunit, a second discharging subunit, a second constant voltage subunit, and a third obtaining subunit;
the second charging subunit is configured to fully charge the battery without pre-lithium with the preset standard multiplying power;
the second discharging subunit is configured to discharge the non-pre-lithium battery with the preset standard multiplying power after the non-pre-lithium battery is fully charged, until the voltage of the non-pre-lithium battery drops to a preset cut-off voltage;
the second constant voltage subunit is configured to maintain the voltage of the non-pre-lithium battery unchanged at the preset cutoff voltage after the voltage of the non-pre-lithium battery drops to the preset cutoff voltage, and perform constant voltage discharge on the non-pre-lithium battery until the current of the non-pre-lithium battery drops to the first preset cutoff current;
the third obtaining subunit is configured to obtain, as the third discharge capacity, a capacity of the non-pre-lithium battery that is discharged during the constant voltage discharge when the current of the non-pre-lithium battery decreases to the first preset off-current.
Optionally, in some optional embodiments, the cycle number determining unit 300 includes: a second number of times determining the sub-unit;
the second-order determining subunit is configured to determine, according to equation 2: and calculating the battery cycle times of the pre-lithium battery, wherein the cycles are the battery cycle times, the C1 is the first discharge capacity, the C2 is the second discharge capacity and the C3 is the third discharge capacity.
The present invention provides a computer-readable storage medium having stored thereon a program which, when executed by a processor, implements the battery cycle life prediction method of any one of the above.
As shown in fig. 4, the present invention provides an electronic device 70, the electronic device 70 comprising at least one processor 701, and at least one memory 702, bus 703 connected to the processor 701; wherein, the processor 701 and the memory 702 complete communication with each other through the bus 703; the processor 701 is configured to invoke program instructions in the memory 702 to perform the battery cycle life prediction method of any of the above.
In the present invention, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In this specification, each embodiment is described in a related manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. In particular, for system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, as relevant to see a section of the description of method embodiments.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.
Claims (10)
1. A battery cycle life prediction method, comprising:
performing a first battery cell cycle on the pre-lithium battery and obtaining a corresponding first discharge capacity, wherein the pre-lithium battery never performs the battery cell cycle before performing the first battery cell cycle on the pre-lithium battery;
performing N times of battery cell cycles on the battery with the pre-lithium, and obtaining a second discharge capacity corresponding to the battery cell cycle with the N th time, wherein the battery cell cycle with the N th time is counted from the first battery cell cycle;
and determining the battery cycle times of the battery with the pre-lithium according to the first discharge capacity and the second discharge capacity.
2. The method of claim 1, wherein performing a first cell cycle on the pre-lithiated battery and obtaining a corresponding first discharge capacity comprises:
fully charging the battery with the pre-lithium according to a preset standard multiplying power;
discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery drops to a preset cut-off voltage;
when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to a first preset cut-off current;
and when the current of the pre-lithium battery drops to the first preset cut-off current, obtaining the capacity of the pre-lithium battery discharged during the constant voltage discharge as the first discharge capacity.
3. The method of claim 2, wherein said subjecting the pre-lithiated battery to N cycles of the cell and obtaining a corresponding second discharge capacity for an nth cycle of the cell comprises:
and performing the battery cell cycle on the battery with the pre-lithium for N times, wherein each time the battery cell cycle is performed: fully charging the pre-lithium battery with the preset standard multiplying power; discharging the pre-lithium battery with the preset standard multiplying power after the pre-lithium battery is fully charged until the voltage of the pre-lithium battery drops to the preset cut-off voltage; when the voltage of the pre-lithium battery is reduced to the preset cut-off voltage, maintaining the voltage of the pre-lithium battery to be the preset cut-off voltage, and performing constant voltage discharge on the pre-lithium battery until the current of the pre-lithium battery is reduced to the first preset cut-off current;
and after carrying out an Nth battery cell cycle on the pre-lithium battery, obtaining the capacity of the pre-lithium battery discharged during constant voltage discharge of the Nth battery cell cycle as the second discharge capacity.
4. The method of claim 3, wherein the determining the number of battery cycles of the pre-lithiated battery based on the first discharge capacity and the second discharge capacity comprises:
according to formula 1: and calculating to obtain the battery cycle times of the battery subjected to pre-lithium, wherein the cycle is the battery cycle times, Q is the preset pre-lithium amount of the battery subjected to pre-lithium, eta is the pre-lithium efficiency of the battery subjected to pre-lithium, and C1 is the first discharge capacity and C2 is the second discharge capacity.
5. The method of claim 3, wherein prior to the determining the number of battery cycles of the pre-lithiated battery based on the first discharge capacity and the second discharge capacity, the method further comprises:
and performing a first cell cycle on the battery without pre-lithium, and obtaining a corresponding third discharge capacity, wherein the battery without pre-lithium never performs the cell cycle before performing the first cell cycle on the battery without pre-lithium.
6. The method of claim 5, wherein performing a first cell cycle on the non-pre-lithiated battery and obtaining a corresponding third discharge capacity comprises:
fully charging the battery without pre-lithium according to the preset standard multiplying power;
discharging the battery without pre-lithium with the preset standard multiplying power after the battery without pre-lithium is fully charged until the voltage of the battery without pre-lithium drops to a preset cut-off voltage;
after the voltage of the battery without pre-lithium is reduced to the preset cut-off voltage, maintaining the voltage of the battery without pre-lithium to be the preset cut-off voltage, and performing constant voltage discharge on the battery without pre-lithium until the current of the battery without pre-lithium is reduced to the first preset cut-off current;
and when the current of the battery without pre-lithium drops to the first preset cut-off current, obtaining the capacity of the battery without pre-lithium discharged during the constant voltage discharge as the third discharge capacity.
7. The method of claim 6, wherein the determining the number of battery cycles of the pre-lithiated battery based on the first discharge capacity and the second discharge capacity comprises:
according to equation 2: and calculating the battery cycle times of the pre-lithium battery, wherein the cycles are the battery cycle times, the C1 is the first discharge capacity, the C2 is the second discharge capacity and the C3 is the third discharge capacity.
8. A battery cycle life prediction apparatus, comprising: a first capacity obtaining unit, a second capacity obtaining unit, and a cycle number determining unit;
the first capacity obtaining unit is used for performing a first battery cell cycle on the battery which is pre-lithiated, and obtaining a corresponding first discharge capacity, wherein the battery which is pre-lithiated never performs the battery cell cycle before the battery cell cycle is performed for the first time on the battery which is pre-lithiated;
the second capacity obtaining unit is configured to perform N times of the cell cycles on the battery that has been pre-lithiated, and obtain a second discharge capacity corresponding to an nth cell cycle, where the nth cell cycle starts counting from the first cell cycle;
the cycle number determining unit is used for determining the battery cycle number of the battery with pre-lithium according to the first discharge capacity and the second discharge capacity.
9. A computer-readable storage medium having a program stored thereon, wherein the program when executed by a processor implements the battery cycle life prediction method according to any one of claims 1 to 7.
10. An electronic device comprising at least one processor, and at least one memory, bus coupled to the processor; the processor and the memory complete communication with each other through the bus; the processor is configured to invoke program instructions in the memory to perform the battery cycle life prediction method of any of claims 1 to 7.
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