CN115184418A - Method and system for analyzing water content of lithium ion battery - Google Patents
Method and system for analyzing water content of lithium ion battery Download PDFInfo
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Abstract
The invention relates to a method and a system for analyzing the water content of a lithium ion battery in the technical field of measurement, which comprises the following steps: more than three groups of batteries with known water content are used for manufacturing reference batteries, and the water content of the more than three groups of reference batteries is different; under the same formation pre-charging condition, all reference batteries are charged to obtain first pre-charging characteristic data, and a reaction voltage range during the side reaction of the moisture and the electrolyte components is obtained; calculating a first side reaction energy difference value of all reference batteries with known water content when water and electrolyte components are subjected to side reaction; establishing a water content-side reaction energy difference standard curve; charging the battery to be tested to obtain second pre-charging characteristic data; calculating a second side reaction energy difference value of the side reaction of the moisture and the electrolyte components when the battery to be detected is in the reaction voltage range; the water content of the battery to be tested is obtained, and the bottleneck that the existing battery water content test cannot realize nondestructive testing due to the fact that the battery is disassembled to measure is broken through.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to a method and a system for analyzing the water content of a lithium ion battery.
Background
The moisture in the lithium ion battery will react with the electrolyte lithium salt in the electrolyte, such as LiPF 6 、LiClO 4 、LiBF 4 、LiAsF 6 The ester solvent in the electrolyte reacts under the action of the hydrofluoric acid to generate LiOH and Li 2 CO 3 、LiCH 2 CH 2 OCO 2 Li and CH 3 OCO 2 Li and other byproducts generate gas, trace amount of the gas is beneficial to film formation of a Solid Electrolyte Interface (SEI) of a battery cathode, but the high water content can influence the film formation quality of the SEI and seriously influences the capacity, service life, safety performance and the like of the battery.
In the prior art, generally, a method for testing the water content of a battery is to disassemble the battery and respectively test the water content of a battery assembly, but the method cannot realize nondestructive testing of the battery.
Disclosure of Invention
The invention provides a method and a system for analyzing the water content of a lithium ion battery aiming at the defects in the prior art, and breaks through the bottleneck that the existing battery water content test needs to be carried out by disassembling the battery and can not realize nondestructive test.
In order to solve the technical problem, the invention is solved by the following technical scheme:
a method for analyzing the water content of a lithium ion battery comprises the following steps:
the method comprises the following steps of (1) making reference batteries by using more than three groups of batteries with known water content, wherein the water content of the more than three groups of the reference batteries is different;
under the same formation pre-charging condition, all the reference batteries are charged to obtain first pre-charging characteristic data, and a reaction voltage range during the side reaction of the moisture and the electrolyte components is obtained;
calculating a first side reaction energy difference value of all the reference cells with known water content when water and electrolyte components are subjected to side reaction based on the first pre-charging characteristic data;
establishing a water content-side reaction energy difference standard curve of a reference battery;
charging a battery to be tested to obtain second pre-charging characteristic data, wherein formation pre-charging conditions of the battery to be tested are the same as those of the reference battery;
calculating a second side reaction energy difference value of side reaction of the moisture and the electrolyte components when the battery to be tested is in the reaction voltage range based on the second pre-charging characteristic data;
and acquiring the water content of the battery to be detected based on the second side reaction energy difference value and the water content-side reaction energy difference standard curve.
Optionally, calculating a first side reaction energy difference value of all the reference cells with known water content when water and electrolyte components are subjected to side reaction, comprising the following steps:
calculating the reference cell reaction energy value of all the reference cells when the moisture and the electrolyte component have side reaction;
a first side reaction energy difference value is calculated based on all of the reference cell reaction energy values.
Optionally, calculating a second side reaction energy difference value of the side reaction of the moisture and the electrolyte component in the reaction voltage range of the battery to be tested based on the second pre-charging characteristic data, including the following steps:
calculating the reaction energy value of the battery to be tested when the battery to be tested performs the side reaction of the moisture and the electrolyte components based on the second pre-charging characteristic data;
and calculating a second side reaction energy difference value based on the reaction energy value of the battery to be detected.
Optionally, the method further comprises the following steps:
and generating a charging capacity-voltage characteristic curve according to the first pre-charging characteristic data.
Optionally, the first pre-charge characteristic data and the second pre-charge characteristic data each include voltage data, current data, and time data.
A lithium ion battery water content analysis system comprises a battery preparation unit, a first formation pre-charging unit, a first calculation unit, a standard curve generation unit, a second formation pre-charging unit, a second calculation unit and a result acquisition unit;
the battery preparation unit is used for preparing reference batteries by using more than three groups of batteries with known water content, and the water content of the more than three groups of reference batteries is different;
the first formation pre-charging unit is used for charging all the reference batteries under the same formation pre-charging condition to obtain first pre-charging characteristic data and acquiring a reaction voltage range when water and electrolyte components react secondarily;
the first calculating unit is used for calculating a first side reaction energy difference value of all the reference batteries with known water contents when water and electrolyte components are subjected to side reaction based on the first pre-charging characteristic data;
the standard curve generating unit is used for establishing a water content-side reaction energy difference standard curve of the reference battery;
the second formation pre-charging unit is used for charging the battery to be tested to obtain second pre-charging characteristic data, wherein the formation pre-charging condition of the battery to be tested is the same as that of the reference battery;
the second calculation unit is used for calculating a second side reaction energy difference value of side reaction of the moisture and the electrolyte components when the battery to be detected is in the reaction voltage range based on the second pre-charging characteristic data;
and the result acquisition unit is used for acquiring the water content of the battery to be detected based on the second side reaction energy difference value and the water content-side reaction energy difference standard curve.
Optionally, the first calculating unit includes a reference cell reaction energy value obtaining unit and a first side reaction energy difference value obtaining unit;
the reference battery reaction energy value acquisition unit is used for calculating the reference battery reaction energy values of all the reference batteries when moisture and electrolyte components are subjected to side reaction;
the first side reaction energy difference value acquisition unit is used for calculating a first side reaction energy difference value based on all the reference battery reaction energy values.
Optionally, the second calculating unit includes a to-be-detected battery reaction energy value obtaining unit and a second secondary reaction energy difference value obtaining unit;
the battery reaction energy value acquisition unit is used for calculating the battery reaction energy value of the battery to be tested when the moisture and the electrolyte component perform side reaction based on the second pre-charging characteristic data;
and the second side reaction energy difference value acquisition unit is used for calculating a second side reaction energy difference value based on the reaction energy value of the battery to be detected and the reaction energy value of the reference battery.
Optionally, the charging apparatus further includes a characteristic curve generating unit, where the characteristic curve generating unit is configured to generate a charging capacity-voltage characteristic curve according to the first pre-charging characteristic data.
A computer-readable storage medium, which stores a computer program, and which, when executed by a processor, performs a method of analyzing moisture content of a lithium-ion battery as in any one of the above.
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
through the lithium ion battery to known water content precharge, thereby obtain the lithium ion battery of this model in the relation of the side reaction energy difference and the water content of moisture with electrolyte component side reaction, and the relation of the side reaction energy difference and the water content that the lithium ion battery through the different water content of multiunit obtained, make final water content-side reaction energy difference standard curve that obtains more accurate, more be close to the actual water content of battery, thereby make the staff can acquire the water content of unknown water content battery according to this standard curve, need not to disassemble the battery, it is simple and harmless to the battery to acquire the battery water content method.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a charge capacity-voltage characteristic curve according to the first embodiment and the second embodiment.
Detailed Description
The present invention will be described in further detail with reference to examples, which are illustrative of the present invention and are not to be construed as being limited thereto.
Example one
A method for analyzing the water content of a lithium ion battery comprises the following steps: more than three groups of batteries with known water content are used for manufacturing reference batteries, and the water content of the more than three groups of reference batteries is different; in this embodiment, three or more reference batteries prepared as 20Ah lithium ion batteries of lithium iron phosphate/graphite system with known battery moisture content are prepared as an example, batteries are prepared by batteries with different moisture contents, and then all the reference batteries are charged under the same charging and precharging condition, wherein the predetermined charging and precharging condition is that after the battery is charged with electrolyte, the batteries are left to stand at 38 ± 2 ℃ for 48 days, and are left to stand at 25 ℃ for 24 hours, and the precharging temperature is 23 ℃ and is charged at a constant current of 0.05C to 30 ℃ SOC, wherein the precharging temperature is generally 23 ℃ to 60 ℃ and the precharging current can be 0.05 to 0.3C, and can be within the range, and the precharging SOC, the lithium iron phosphate/graphite system batteries are generally 0 to 30% SOC, and the ternary material/graphite system batteries are generally 0 to 50% SOC, and the first precharging characteristic data is obtained, and the reaction voltage range of the moisture and the electrolyte component side reaction is obtained, and the lithium ion battery moisture and the electrolyte component side reaction side is by-film formation reaction by-product in the charging process of the three types of the batteries, namely, the first lithium ion initial stage, SEI and the lithium ion migration stage and the lithium ion migration reaction side in the lithium ion side reaction stage.
As shown in FIG. 1, the charging capacity-voltage characteristics are generated according to the first pre-charging characteristic dataThe characteristic curve is that only the only variable with different water content exists between each group of reference batteries, so the non-coincident part of the two curves in the figure is the reaction stage (t) of the water content and the electrolyte by-product in the lithium ion battery 2 ～t 3 ) I.e. the first solid electrolyte interface film (SEI) formation (t) 0 ～t 1 ) And a previous stage (t) of lithium ion normality 1 ～t 2 ) The curves are overlapped, and the area of the non-overlapped part is the first side reaction energy difference value between the reference batteries with different water contents, so that the reaction energy value of the reference battery generated in the stage of reacting the water content in the reference battery with the electrolyte by-product is required to be obtained.
Specifically, based on the first pre-charging characteristic data, calculating a first side reaction energy difference value of all reference batteries with known water content when water and electrolyte components are subjected to side reaction, and the method comprises the following steps of: calculating reference cell reaction energy values of all the reference cells when the moisture reacts with the electrolyte component, and calculating a first side reaction energy difference value based on all the reference cell reaction energy values.
Further, it is first required to calculate the starting time and the ending time of the side reaction stage of the moisture and the electrolyte component according to the first pre-charging characteristic data obtained during the pre-charging, wherein, since the first pre-charging characteristic data includes the voltage data, the current data and the time data, at this time, the reference capacitance per time unit can be calculated by the voltage data and the current data, wherein the calculation formula of the reference capacitance is Q Reference device ＝I Reference of ×T Reference device (ii) a Then comparing the time points of equal reference capacitance and equal voltage of more than three groups of reference batteries at the same time to obtain the starting time and the ending time of the side reaction stage of the water and the electrolyte components, then calculating the reaction energy value of the reference battery at the beginning of the reaction according to the starting time, the current value corresponding to the starting time and the voltage value corresponding to the starting time, and calculating the reaction energy value of the reference battery at the end of the reaction according to the ending time, the current value corresponding to the ending time and the voltage value corresponding to the ending time, wherein the calculation formula of the reaction energy value of the reference battery is as follows:
then, a first side reaction energy difference value delta E1 (I, V, t) is calculated through the reference battery reaction energy value at the beginning of the reaction and the reference battery reaction energy value at the end of the reaction, and then a water content-side reaction energy difference standard curve of the reference battery is established according to the water content of each group of reference batteries and the corresponding first side reaction energy difference value, such as Q shown in figure 1 t2 、V t2 I.e. the voltage value and the reference capacitance, Q, at the beginning of the side reaction of the starting water and the electrolyte components t3 、V t3 The voltage value and the reference capacitance when the side reaction of the initial water content and the electrolyte component is finished can be used for calculating the first side reaction energy difference value of a plurality of groups of batteries with different water contents so as to ensure the accuracy of the water content-side reaction energy difference standard curve of the reference battery, thereby enabling the standard curve to be closer to the reality.
After the standard curve of the water content-side reaction energy difference of the reference battery is established, the water content of the battery to be detected can be detected and analyzed, therefore, the battery to be detected needs to be charged first to obtain second pre-charging characteristic data, wherein the formation pre-charging condition of the battery to be detected is the same as that of the reference battery, the second pre-charging characteristic data also comprises voltage data, current data and time data, then a second side reaction energy difference value of the side reaction of the water and the electrolyte components when the battery to be detected is in a reaction voltage range is calculated based on the second pre-charging characteristic data, and specifically, the reaction energy value of the battery to be detected when the water and the electrolyte components are in the side reaction needs to be calculated based on the second pre-charging characteristic data; and calculating a second side reaction energy difference value based on the reaction energy value of the battery to be detected.
Furthermore, as for the working staff, the moisture content of the lithium ion battery which is taken first cannot be known, but the change of the electric quantity of the lithium ion battery after charging can be known, therefore, second pre-charging characteristic data in a reaction voltage range is selected, then the reaction energy value of the battery to be measured at the starting time and the ending time of the side reaction of the moisture and the electrolyte components of the battery to be measured is calculated, the calculation formula is the same as that of the reference battery, and a second side reaction energy difference value Δ E2 (I, V, t) is calculated, then the moisture content of the battery to be measured is obtained according to the second side reaction energy difference value and a moisture content-side reaction energy difference standard curve, and it needs to be noted that the reaction voltage range refers to the voltage range corresponding to the starting time and the stopping time of the reaction of the moisture and the electrolyte by-products.
Through the method of the embodiment, when a worker encounters a battery with unknown water content, the water content of the battery to be detected can be obtained by calculating the second side reaction energy difference value of the battery to be detected and combining the water content-side reaction energy difference standard curve, so that the worker can know the water content in the battery without detaching the battery, the battery is more convenient and is not required to be damaged, and the aim of quantitatively and nondestructively detecting the battery content in the pre-charging stage during manufacturing is fulfilled.
Example two
A lithium ion battery water content analysis system comprises a battery preparation unit, a first formation pre-charging unit, a first calculation unit, a standard curve generation unit, a second formation pre-charging unit, a second calculation unit and a result acquisition unit; the battery preparation unit is used for preparing more than three groups of batteries with known water content into reference batteries, and the water content of the more than three groups of reference batteries is different; in this embodiment, three or more reference batteries manufactured may be 20Ah lithium ion batteries of lithium iron phosphate/graphite system with known battery moisture content, for example, batteries are manufactured by batteries with different moisture contents, and then the first formation pre-charging unit charges all the reference batteries under the same formation pre-charging condition, wherein the pre-charging condition of the batteries is that after battery injection, the batteries are left to stand at 38 ± 2 ℃ for 48 days and are left to stand at 25 ℃ for 24 hours, and the pre-charging temperature is at 23 ℃ and is constant-current charged to 30 SOC at 0.05C, it is noted that the pre-charging temperature is typically at 23 ℃ to 60 ℃ and the pre-charging current may be 0.05 to 0.3C, and the pre-charging SOC may be obtained in this range, and the pre-charging SOC, the lithium iron phosphate/graphite system batteries are typically 0 to 30% SOC, the ternary material/graphite system batteries are typically 0 to 50% SOC, and the first pre-charging characteristic data are obtained and the reaction voltage range of the electrolyte and the lithium ion battery components are obtained when the lithium ion battery moisture and the lithium ion battery is reacted, and the lithium ion battery is in the first pre-charging stage and the electrolyte migration stage.
The lithium ion battery water content analysis system further comprises a characteristic curve generation unit for generating a charging capacity-voltage characteristic curve according to the first pre-charging characteristic data, as shown in fig. 1, the charging capacity-voltage characteristic curve is generated according to the first pre-charging characteristic data, and because only unique variables with different water contents exist between each group of reference batteries, a non-overlapping part of the two curves in the graph is a reaction stage (t) of the water content and the electrolyte by-products in the lithium ion battery (t) 2 ～t 3 ) I.e. the first solid electrolyte interface film (SEI) formation (t) 0 ～t 1 ) And a previous stage (t) of lithium ion normality 1 ～t 2 ) The curves are overlapped, and the area of the non-overlapped part is the first side reaction energy difference value between the reference batteries with different water contents, so that the reaction energy value of the reference battery generated in the stage of reacting the water content in the reference battery with the electrolyte by-product is required to be obtained.
Specifically, the first calculating unit is configured to calculate, based on the first pre-charge characteristic data, a first side reaction energy difference value of all reference cells with known water content during a side reaction between water and an electrolyte component, and the first calculating unit includes a reference cell reaction energy value obtaining unit and a first side reaction energy difference value obtaining unit; the reference cell reaction energy value obtaining unit is used for calculating reference cell reaction energy values of all the reference cells when moisture and electrolyte components are subjected to side reaction, and the first side reaction energy difference value obtaining unit is used for calculating a first side reaction energy difference value based on all the reference cell reaction energy values.
Further, it is first necessary to calculate the start time and the end time of the phase of the side reaction of moisture with the electrolyte component, due to the first precharge characteristic data acquired at the time of prechargingThe characteristic data comprises voltage data, current data and time data, and the reference capacitance of each time unit can be calculated by the voltage data and the current data, wherein the calculation formula of the reference capacitance is Q Reference device ＝I Reference of ×T Reference device (ii) a Then comparing the time points of equal reference capacitance and equal voltage of more than three groups of reference batteries at the same time to obtain the starting time and the ending time of the side reaction stage of the water and the electrolyte components, then calculating the reaction energy value of the reference battery at the beginning of the reaction according to the starting time, the current value corresponding to the starting time and the voltage value corresponding to the starting time, and calculating the reaction energy value of the reference battery at the end of the reaction according to the ending time, the current value corresponding to the ending time and the voltage value corresponding to the ending time, wherein the calculation formula of the reaction energy value of the reference battery is as follows:
then, a first side reaction energy difference value Δ E1 (I, V, t) is calculated from the reference cell reaction energy value at the start of the reaction and the reference cell reaction energy value at the end of the reaction, and then a standard curve of water content-side reaction energy difference of the reference cell is established by a standard curve generating unit according to the water content of each set of reference cells and the corresponding first side reaction energy difference value, as shown in fig. 1 as Q t2 、V t2 I.e. the voltage value and the reference capacitance, Q, at the beginning of the side reaction of the starting water and the electrolyte components t3 、V t3 The voltage value and the reference capacitance are obtained when the side reaction of the initial water and the electrolyte components is finished, and in order to ensure the accuracy of the water content-side reaction energy difference standard curve of the reference battery, the first side reaction energy difference values of a plurality of groups of batteries with different water contents can be calculated through the steps, so that the standard curve is closer to the reality.
After the establishment of the water content-side reaction energy difference standard curve of the reference battery is completed, the water content of the battery to be detected can be detected and analyzed, therefore, the battery to be detected needs to be charged through a second formation pre-charging unit to obtain second pre-charging characteristic data, wherein the formation pre-charging condition of the battery to be detected is the same as that of the reference battery, the second pre-charging characteristic data also comprises voltage data, current data and time data, then a second calculation unit calculates a second side reaction energy difference value of the side reaction of the water and the electrolyte component when the battery to be detected is in a reaction voltage range based on the second pre-charging characteristic data, specifically, the second calculation unit comprises a battery reaction energy value acquisition unit to be detected and a second side reaction energy difference value acquisition unit, and the battery to-be-detected reaction energy value of the battery to be detected in the side reaction of the water and the electrolyte component needs to be calculated based on the second pre-charging characteristic data through the battery reaction energy value acquisition unit to be detected; and calculating a second side reaction energy difference value based on the reaction energy value of the battery to be detected through a second side reaction energy difference value acquisition unit.
Furthermore, as for the working personnel, the moisture content of the lithium ion battery which is taken first cannot be known, but the change of the electric quantity of the lithium ion battery after charging can be known, therefore, second pre-charging characteristic data within the reaction voltage range is selected, then the reaction energy value of the battery to be measured at the starting time and the ending time of the side reaction of the moisture and the electrolyte component of the battery to be measured is calculated, the calculation formula is the same as that of the reference battery, and the second side reaction energy difference value Δ E2 (I, V, t) is calculated, then the moisture content of the battery to be measured is obtained by the result obtaining unit according to the second side reaction energy difference value and the moisture content-side reaction energy difference standard curve, and it needs to be noted that the reaction voltage range refers to the voltage range corresponding to the starting time and the stopping time of the reaction of the moisture and the electrolyte by-product.
Through the system of this embodiment, when the staff met the battery of unknown water content, can be through calculating the second side reaction energy difference value of the battery that awaits measuring to combine water content-side reaction energy difference standard curve, acquire the water content of the battery that awaits measuring, make the staff need not to dismantle the battery, can learn the water content in the battery, more convenient and need not to damage the battery, realized during the precharge stage in the time of making, quantitative, nondestructively detect out battery content.
A computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the method for detecting an unauthorized access hole according to the first embodiment is performed.
More specific examples of the computer readable storage medium may include, but are not limited to: an electrical connection having one or more wire segments, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
In the context of this application, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In this application, however, a computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: wireless section, wire section, fiber optic cable, RF, etc., or any suitable combination of the foregoing.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. For example, the above-described device embodiments are merely illustrative, and for example, the division of the modules, or units is only one type of division of logical functions, and there may be other divisions in actual implementation, for example, multiple units, modules, or components may be combined or integrated into another device, or some features may be omitted, or not executed.
The units may or may not be physically separate, and components displayed as units may be one physical unit or a plurality of physical units, that is, may be located in one place, or may be distributed in a plurality of different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit.
In particular, according to embodiments of the present disclosure, the processes described above with reference to the flow diagrams may be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer-readable medium, the computer program comprising program code for performing the method illustrated by the flow chart. In such an embodiment, the computer program may be downloaded and installed from a network via the communication section, and/or installed from a removable medium. The computer program, when executed by a Central Processing Unit (CPU), performs the above-described functions defined in the method of the present application. It should be noted that the computer readable medium mentioned above in the present application may be a computer readable signal medium or a computer readable storage medium or any combination of the two. The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
It should be noted that the above-mentioned embodiments are only specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. The method for analyzing the water content of the lithium ion battery is characterized by comprising the following steps of:
the method comprises the following steps of (1) making reference batteries by using more than three groups of batteries with known water content, wherein the water content of the more than three groups of the reference batteries is different;
under the same formation pre-charging condition, all the reference batteries are charged to obtain first pre-charging characteristic data, and a reaction voltage range when water and electrolyte components react by side is obtained;
calculating a first side reaction energy difference value of all the reference cells with the known water content when the water and the electrolyte components are subjected to side reaction based on the first pre-charging characteristic data;
establishing a water content-side reaction energy difference standard curve of a reference battery;
charging a battery to be tested to obtain second pre-charging characteristic data, wherein formation pre-charging conditions of the battery to be tested are the same as those of the reference battery;
calculating a second side reaction energy difference value of side reaction of the moisture and the electrolyte components when the battery to be tested is in the reaction voltage range based on the second pre-charging characteristic data;
and acquiring the water content of the battery to be detected based on the second side reaction energy difference value and the water content-side reaction energy difference standard curve.
2. The method for analyzing the water content of the lithium ion battery according to claim 1, wherein the step of calculating the first side reaction energy difference value of all the reference batteries with known water content during the side reaction of the water and the electrolyte components comprises the following steps:
calculating the reference battery reaction energy value of all the reference batteries when the moisture and the electrolyte components are subjected to side reaction;
a first side reaction energy difference value is calculated based on all of the reference cell reaction energy values.
3. The method for analyzing the water content of the lithium ion battery according to claim 1, wherein a second side reaction energy difference value of a side reaction between water and electrolyte components of the battery to be tested in the reaction voltage range is calculated based on the second pre-charging characteristic data, and the method comprises the following steps:
calculating the reaction energy value of the battery to be tested when the battery to be tested has the side reaction of the moisture and the electrolyte components based on the second pre-charging characteristic data;
and calculating a second side reaction energy difference value based on the reaction energy value of the battery to be detected.
4. The method for analyzing the water content of the lithium ion battery according to claim 1, further comprising the steps of:
and generating a charging capacity-voltage characteristic curve according to the first pre-charging characteristic data.
5. The method of claim 1, wherein the first pre-charge characteristic data and the second pre-charge characteristic data each comprise voltage data, current data, and time data.
6. A lithium ion battery water content analysis system is characterized by comprising a battery preparation unit, a first formation pre-charging unit, a first calculation unit, a standard curve generation unit, a second formation pre-charging unit, a second calculation unit and a result acquisition unit;
the battery preparation unit is used for preparing reference batteries by using more than three groups of batteries with known water content, and the water content of the more than three groups of reference batteries is different;
the first formation pre-charging unit is used for charging all the reference batteries under the same formation pre-charging condition to obtain first pre-charging characteristic data and acquiring a reaction voltage range when water and electrolyte components react secondarily;
the first calculating unit is used for calculating a first side reaction energy difference value of all the reference batteries with the known water content when water and electrolyte components are subjected to side reaction based on the first pre-charging characteristic data;
the standard curve generating unit is used for establishing a water content-side reaction energy difference standard curve of the reference battery;
the second formation pre-charging unit is used for charging the battery to be tested to obtain second pre-charging characteristic data, wherein the formation pre-charging condition of the battery to be tested is the same as that of the reference battery;
the second calculation unit is used for calculating a second side reaction energy difference value of side reaction of moisture and electrolyte components when the battery to be detected is in the reaction voltage range based on the second pre-charging characteristic data;
and the result acquisition unit is used for acquiring the water content of the battery to be detected based on the second side reaction energy difference value and the water content-side reaction energy difference standard curve.
7. The system according to claim 6, wherein the first calculating unit comprises a reference cell reaction energy value obtaining unit and a first side reaction energy difference value obtaining unit;
the reference battery reaction energy value acquisition unit is used for calculating the reference battery reaction energy values of all the reference batteries when moisture and electrolyte components are subjected to side reaction;
the first side reaction energy difference value acquisition unit is used for calculating a first side reaction energy difference value based on all the reference battery reaction energy values.
8. The system for analyzing water content in lithium ion batteries according to claim 6, wherein said second calculating unit comprises a reaction energy value obtaining unit of the battery to be tested and a second side reaction energy difference value obtaining unit;
the battery reaction energy value acquisition unit is used for calculating the battery reaction energy value of the battery to be tested when the moisture and the electrolyte component perform side reaction based on the second pre-charging characteristic data;
and the second side reaction energy difference value acquisition unit is used for calculating a second side reaction energy difference value based on the reaction energy value of the battery to be detected and the reaction energy value of the reference battery.
9. The lithium ion battery water content analysis system according to claim 6, further comprising a characteristic curve generation unit configured to generate a charging capacity-voltage characteristic curve according to the first pre-charging characteristic data.
10. A computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the method for analyzing moisture content of a lithium ion battery according to any one of claims 1 to 5 is performed.
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| CN109030567A (en) * | 2018-07-06 | 2018-12-18 | 力信（江苏）能源科技有限责任公司 | A kind of lithium-ion electric core water content inside method of discrimination |
| CN110470702A (en) * | 2019-07-10 | 2019-11-19 | 深圳市比克动力电池有限公司 | A kind of lithium-ion battery electrolytes and battery core determination of moisture method |
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| CN109030567A (en) * | 2018-07-06 | 2018-12-18 | 力信（江苏）能源科技有限责任公司 | A kind of lithium-ion electric core water content inside method of discrimination |
| CN110470702A (en) * | 2019-07-10 | 2019-11-19 | 深圳市比克动力电池有限公司 | A kind of lithium-ion battery electrolytes and battery core determination of moisture method |
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