Detection method for quantitatively detecting distribution of electrolyte in battery and application
阅读说明：本技术 一种定量检测电池内部电解液分布的检测方法及用途 (Detection method for quantitatively detecting distribution of electrolyte in battery and application ) 是由 王娇娇 李树贤 杨红新 骆兆军 高飞 何见超 张要军 于 2021-09-26 设计创作，主要内容包括：本发明提供了一种定量检测电池内部电解液分布的检测方法及用途,所述的检测方法包括：对样品电池进行电化学阻抗测试或电压测试得到相应的测试曲线；对样品电池的极片进行ICP测试,得到极片中的电解液含量分布图,建立电解液含量分布图与测试曲线的映射关系；对待测电池进行通过进行电化学阻抗测试或电压测试,通过测试结果结合映射关系,推断待测电池极片中的电解液含量分布状态。本发明通过电化学阻抗测试或电压测试和ICP法定点定量检测得到二者之间的映射关系,使得电解液在电池内部的分布情况可以规模化定量检测,操作简单,数据结果可靠,这为优化电池的生产工艺起到了推进作用,为预测电池的安全性、循环性提供理论基础。(The invention provides a detection method for quantitatively detecting the distribution of electrolyte in a battery and application thereof, wherein the detection method comprises the following steps: carrying out electrochemical impedance test or voltage test on the sample battery to obtain a corresponding test curve; carrying out ICP test on a pole piece of the sample battery to obtain an electrolyte content distribution diagram in the pole piece, and establishing a mapping relation between the electrolyte content distribution diagram and a test curve; and carrying out electrochemical impedance test or voltage test on the battery to be tested, and deducing the distribution state of the electrolyte content in the battery pole piece to be tested by combining the test result with the mapping relation. The invention obtains the mapping relation between the electrochemical impedance test or the voltage test and the ICP legal point quantitative test, so that the distribution condition of the electrolyte in the battery can be quantitatively detected in a large scale, the operation is simple, the data result is reliable, the production process of the battery is optimized, and the theoretical basis is provided for predicting the safety and the cyclicity of the battery.)
1. A detection method for quantitatively detecting the distribution of electrolyte in a battery is characterized by comprising the following steps:
carrying out electrochemical impedance test or voltage test on the sample battery to obtain a corresponding test curve; carrying out ICP test on a pole piece of the sample battery to obtain an electrolyte content distribution diagram in the pole piece, and establishing a mapping relation between the electrolyte content distribution diagram and a test curve; and carrying out electrochemical impedance test or voltage test on the battery to be tested, and deducing the distribution state of the electrolyte content in the battery pole piece to be tested by combining the test result with the mapping relation.
2. The detection method according to claim 1, wherein the ICP test procedure specifically comprises:
disassembling a sample battery to obtain a pole piece, selecting different points to be tested on the pole piece, cutting to obtain sample pieces, soaking the sample pieces respectively to obtain a soak solution containing electrolyte, carrying out ICP (inductively coupled plasma) test on the soak solution, and calculating to obtain the electrolyte content in the soak solution; and synthesizing the electrolyte content in each sample plate to obtain the electrolyte content distribution diagram of the pole piece.
3. The detection method according to claim 2, wherein the mapping relationship is established as follows:
carrying out electrochemical impedance test or voltage test on a sample battery under a determined aging time to obtain a test result under the aging time; after the electrochemical impedance test or the voltage test is finished, directly disassembling the sample battery and carrying out ICP test on the pole piece in the sample battery to obtain an electrolyte content distribution diagram under the aging time;
(II) selecting a brand-new sample battery which is completely the same as the sample battery used previously, re-determining the aging time, and repeating the step (I); and analogizing until all tests under the preset aging time are finished, obtaining test curves under different aging times and electrolyte content distribution maps under corresponding aging times, and establishing a mapping relation between the test curves and the electrolyte content distribution maps under different aging times.
4. The detection method according to claim 2 or 3, wherein after the sample battery is disassembled, pole pieces between different layers in the battery core are selected, and at least one point to be detected is selected from each pole piece to be cut to obtain the sample piece;
preferably, at least one pole piece is taken from each of the upper layer, the middle layer and the lower layer of the battery core.
5. The detection method according to any one of claims 2 to 4, wherein at least one point to be detected is selected in a half area of the pole piece, an electrolyte content distribution map in the half area is obtained after ICP testing, and the electrolyte content distribution map of the whole pole piece is obtained after mirroring the electrolyte content distribution map in the half area;
preferably, 10-15 points to be detected are uniformly selected in a half area of the pole piece.
6. The detection method according to any one of claims 2 to 5, wherein the sample piece is a circular thin plate;
preferably, the diameter of the circular thin slice is 10-15 mm.
7. The assay of any one of claims 1-6 wherein the electrolyte comprises LiPF6。
8. The detection method according to claim 2, 4 or 6, wherein the test piece is immersed in deionized water or king water;
preferably, the soaking time is 1-2 h.
9. The detection method according to any one of claims 1 to 8, characterized in that at least 5 aging time point values are selected within the range of 1 to 48h, and the time intervals between the aging time point values are the same.
10. The use of the detection method for quantitatively detecting the distribution of the electrolyte in the battery according to any one of claims 1 to 9, wherein the detection method is used for obtaining the content distribution diagram of the electrolyte in an electrode plate in the battery on the premise of not disassembling the battery.
Technical Field
The invention belongs to the technical field of battery detection, and relates to a detection method for quantitatively detecting distribution of electrolyte in a battery and application thereof.
Background
The electrolyte solution is an important component of lithium ion batteries, and is Li+A bridge for transmission between the anode and the cathode. The electrolyte of lithium ion battery is generally non-aqueous electrolyte composed of organic solvent (such as PC, EC and DMC, etc.) and conductive salt (such as LiPF)6、LiBF4And LiClO4Etc.) of the composition. At present, the rapidly developed lithium ion battery still has many problems, such as the safety performance, the cycle performance, the electrochemical performance and the like of the battery core. These problems are closely related to the distribution of the electrolyte inside the battery, and the uniformity of the distribution of the electrolyte in the lithium ion battery is one of the key elements determining the performance of the battery. The distribution uniformity of the electrolyte inside the battery core is influenced by a plurality of factors such as anode and cathode materials, a diaphragm, an injection mode, the components of the electrolyte and the like. At present, the method for detecting the distribution condition of the electrolyte in the lithium ion battery can be divided into the following steps: spectroscopic, mass spectrometry and electrochemical methods.
And (3) spectrometry: (1) and (4) observing the electrolyte infiltration process in situ by using a neutron imaging technology. As neutrons have stronger penetrating power and sensibility to Li and H atoms, the neutrons are absorbed by the electrolyte when penetrating through the battery cell to obtain an optical image. (2) Ultrasonic imaging characterizes the electrolyte wetting state in the cell. The principle of the method is that ultrasonic waves are generated by a focusing sensor on one side, penetrate through a battery, are influenced by materials in the battery, are received by a receiver on the other side, and ultrasonic transmission images of different areas of the battery are obtained. (3) And (4) representing the infiltration degree of the electrolyte by a tracking marking method. And mixing the isotope elements, the fluorescent substances or the colored substances with the electrolyte, injecting the mixture into the battery core, tracking and marking the infiltration process of the electrolyte, and qualitatively obtaining the distribution condition of the electrolyte in the battery.
Mass spectrometry: (1) quantitative measurement of organic solvents. The distribution condition of the electrolyte on the pole piece is deduced by extracting the organic solvent on the pole piece and quantitatively testing the organic components by using a GC-MS (gas chromatography-mass spectrometer). (2) Quantitative measurement of lithium salt. By extracting lithium salt on the pole piece, anions in the electrolyte have different peak output times in an IC test (ion liquid chromatography), and the anion concentration, namely the lithium salt concentration, is quantitatively determined through the integral area of a characteristic peak, so that the distribution condition of the electrolyte on the pole piece is deduced.
Electrochemical method: the change of the high-frequency area test resistance reflects the condition of electrolyte infiltration in the battery core. Namely: the RHFR is gradually reduced to indicate that the electrolyte inside the cell is gradually infiltrated, the RHFR is reduced to the minimum value and is kept stable, and the infiltration is indicated to be completed. For example, the infiltration speed of the battery electrolyte can be rapidly evaluated by using an alternating current impedance method.
The distribution of the electrolyte in the battery is mainly detected by qualitative or quantitative measurement through the three means, so that the performance of the battery is monitored, and the safety performance of the lithium ion battery is guaranteed.
CN105628685A discloses a method for determining electrolyte distribution in a lithium ion battery cell, which specifically comprises: and (2) filling electrolyte containing a tracer element into the lithium ion battery to be tested, determining the content of the tracer element in the part to be tested of the lithium ion battery core by adopting an ion tracer method, calculating the actual distribution quantity of the electrolyte in each area of the part to be tested, and obtaining the distribution difference value of the electrolyte by calculating the difference between the actual distribution quantity of the electrolyte and the theoretical absorption quantity of the electrolyte.
CN110148793A discloses a method for judging the electrolyte infiltration state of a lithium ion battery, which comprises the following steps: (1) preparing a colored impregnating compound, adding the colored impregnating compound into the electrolyte, and uniformly mixing to obtain a colored electrolyte; (2) injecting colored electrolyte into the battery, respectively disassembling the battery when the battery completes primary injection, formation and secondary injection procedures, and judging the infiltration state of the electrolyte according to whether the color areas on the diaphragm and the pole piece are uniformly distributed so as to adjust the primary injection amount, the secondary injection amount and the formation process.
CN109142451A discloses a method for evaluating infiltration speed of battery electrolyte, which provides a first battery cell, a second battery cell, an improved electrolyte, and a raw electrolyte, where the first battery cell and the second battery cell are the same battery cell, after the improved electrolyte is injected into the first battery cell, impedances of the first battery cell at a beginning and a tail of a first time interval are respectively measured to obtain a first impedance difference, after the raw electrolyte is injected into the second battery cell, impedances of the second battery cell at a beginning and a tail of the first time interval are respectively measured to obtain a second impedance difference, a magnitude of the first impedance difference and a magnitude of the second impedance difference are compared, if the first impedance difference is greater than the second impedance difference, the infiltration speed of the improved electrolyte is fast, otherwise, the infiltration speed of the improved electrolyte is slow.
The existing method for representing the infiltration state of the electrolyte in the battery has advantages and disadvantages, but the method is difficult to monitor the infiltration condition of the electrolyte under different conditions. Under the action of not damaging the battery core, the spectrum method can qualitatively detect the distribution condition of the electrolyte in the battery core, but the spectrum method generally involves a relatively high-end instrument, is expensive, has high test cost, and cannot perform fixed-point quantitative measurement on the distribution of the electrolyte in the battery core. Meanwhile, the spectroscopy also involves the introduction of some isotopes, fluorescent substances or colored substances, and the introduction of the substances may affect the fluidity, wettability and other properties of the electrolyte, so that the infiltration condition of the electrolyte on the battery cell cannot be truly and effectively reflected.
The mass spectrometry can carry out quantitative analysis on the distribution condition of the electrolyte, but the battery core needs to be disassembled, so that the operation is complex, and batch detection on the battery core is difficult to realize. The electrochemical method is a method for quantitatively analyzing the distribution condition of the electrolyte in the battery cell more simply and efficiently, but the electrochemical method is difficult to realize fixed-point quantitative measurement on the distribution of the electrolyte in the battery cell.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a detection method for quantitatively detecting the distribution of electrolyte in a battery and application thereof. The distribution condition of electrolyte in the battery core can be quantitatively determined at fixed points, the operation is simple, the data result is reliable, the production process of the battery is optimized, and a theoretical basis is provided for predicting the safety and the circularity of the battery.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a detection method for quantitatively detecting electrolyte distribution in a battery, the detection method comprising:
carrying out electrochemical impedance test or voltage test on the sample battery to obtain a corresponding test curve; carrying out ICP test on a pole piece of the sample battery to obtain an electrolyte content distribution diagram in the pole piece, and establishing a mapping relation between the electrolyte content distribution diagram and a test curve; and carrying out electrochemical impedance test or voltage test on the battery to be tested, and deducing the distribution state of the electrolyte content in the battery pole piece to be tested by combining the test result with the mapping relation.
The invention obtains the mapping relation between the electrochemical impedance test (or voltage test) and the ICP legal point quantitative detection, so that the distribution condition of the electrolyte in the battery can be quantitatively detected in a large scale. The distribution condition of electrolyte in the battery core can be quantitatively determined at fixed points, the operation is simple, the data result is reliable, the production process of the battery is optimized, and a theoretical basis is provided for predicting the safety and the circularity of the battery.
It should be noted that the mapping relationship obtained by the present invention is actually that the ac impedance map (or voltage value) at each specific aging time corresponds to an electrolyte content distribution map at the aging time. When the electrolyte content distribution condition of other batteries to be tested is tested, only the alternating current impedance (or voltage) of the battery to be tested needs to be tested, the electrolyte content distribution diagram of the battery to be tested can be obtained by directly contrasting the mapping relation with the alternating current impedance diagram (or voltage) of the battery to be tested, and the electrolyte content distribution diagram of an internal battery core can be obtained without disassembling the battery to be tested.
It is noted that the electrochemical impedance test, the voltage test and the ICP test are all well known test methods in the art. Specifically, the method comprises the following steps:
the alternating current impedance method (EIS) is to disturb a system by using a small-amplitude alternating current signal and observe the influence of the system on disturbance response in a steady state. In general, an alternating current (generally sinusoidal) voltage signal of small amplitude is applied to the electrodes to perturb the electrode potential around the equilibrium electrode potential, and after reaching a steady state, the amplitude or phase of the response current signal is measured and the complex impedance of the electrodes is calculated in sequence. And then according to the equivalent circuit, calculating the kinetic parameters of the electrode reaction through the analysis and parameter fitting of the impedance spectrum.
ICP test, which is called inductive coupling plasma atomic emission spectrometry, applies high-frequency energy provided by a radio frequency generator to an inductive coupling coil, and places a plasma torch tube at the center of the coil, so that a high-frequency electromagnetic field is generated in the torch tube, micro sparks are used for ignition, the ArF introduced into the torch tube is ionized, electrons and ions are generated to conduct electricity, the conductive gas is acted by the high-frequency electromagnetic field to form an eddy current area concentric with the coupling coil, and high heat is generated by strong current, so that plasma in a torch shape and capable of being self-sustained is formed, and the plasma is in a ring structure due to the skin effect of the high-frequency current and the action of carrier gas of an inner tube. After the sample is carried into the atomizing system by the carrier gas for atomization, the sample enters an axial channel of the plasma in the form of aerosol, and is fully evaporated, atomized, ionized and excited in high-temperature and inert atmosphere, and characteristic spectral lines of contained elements are emitted. Identifying whether the sample contains a certain element according to the existence of the characteristic spectral line (qualitative analysis); and determining the content of the corresponding element in the sample according to the characteristic spectral line intensity (quantitative analysis).
As a preferred technical solution of the present invention, the ICP test process specifically includes:
disassembling a sample battery to obtain a pole piece, selecting different points to be tested on the pole piece, cutting to obtain sample pieces, soaking the sample pieces respectively to obtain a soak solution containing electrolyte, carrying out ICP (inductively coupled plasma) test on the soak solution, and calculating to obtain the electrolyte content in the soak solution; and synthesizing the electrolyte content in each sample plate to obtain the electrolyte content distribution diagram of the pole piece.
As a preferred technical solution of the present invention, the mapping relationship is established in the following manner:
carrying out electrochemical impedance test or voltage test on a sample battery under a determined aging time to obtain a test result under the aging time; after the electrochemical impedance test or the voltage test is finished, directly disassembling the sample battery and carrying out ICP test on the pole piece in the sample battery to obtain an electrolyte content distribution diagram under the aging time;
(II) selecting a brand-new sample battery which is completely the same as the sample battery used previously, re-determining the aging time, and repeating the step (I); and analogizing until all tests under the preset aging time are finished, obtaining test curves under different aging times and electrolyte content distribution maps under corresponding aging times, and establishing a mapping relation between the test curves and the electrolyte content distribution maps under different aging times.
As a preferred technical scheme of the present invention, after the sample battery is disassembled, pole pieces between different layers in the battery core are selected, and at least one point to be measured is selected on each pole piece and cut to obtain the sample piece.
Preferably, at least one pole piece is taken from each of the upper layer, the middle layer and the lower layer of the battery core.
As a preferred technical scheme of the invention, at least one point to be tested is selected in a half area of the pole piece, an ICP test is carried out to obtain an electrolyte content distribution diagram in the half area, and the electrolyte content distribution diagram in the half area is mirrored to obtain the electrolyte content distribution diagram of the whole pole piece.
Preferably, 10 to 15 points to be measured are uniformly selected in a half area of the pole piece, for example, 10, 11, 12, 13, 14, or 15 points to be measured are selected, but not limited to the enumerated values, and other unrecited values in the range of the enumerated values are also applicable.
In a preferred embodiment of the present invention, the sample piece is a circular thin sheet.
Preferably, the circular sheet has a diameter of 10 to 15mm, for example, 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, 13mm, 13.5mm, 14mm, 14.5mm or 15mm, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.
As a preferable technical solution of the present invention, the electrolyte includes LiPF6。
As a preferable technical scheme of the invention, the sample piece is soaked in deionized water or king water.
Preferably, the soaking time is 1 to 2 hours, for example, 1.0 hour, 1.1 hour, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2.0 hours, but is not limited to the enumerated values, and other values in the numerical range are also applicable.
As a preferable technical scheme of the invention, at least 5 aging time point values are selected within the range of 1-48 h, and the time intervals among the aging time point values are the same.
In a second aspect, the invention provides a use of the detection method for quantitatively detecting the distribution of the electrolyte in the battery in the first aspect, and the detection method is used for obtaining the content distribution diagram of the electrolyte in the battery electrode plate on the premise of not disassembling the battery.
Compared with the prior art, the invention has the beneficial effects that:
the invention obtains the mapping relation between the electrochemical impedance test (or voltage test) and the ICP legal point quantitative detection, so that the distribution condition of the electrolyte in the battery can be quantitatively detected in a large scale. The distribution condition of electrolyte in the battery core can be quantitatively determined at fixed points, the operation is simple, the data result is reliable, the production process of the battery is optimized, and a theoretical basis is provided for predicting the safety and the circularity of the battery.
Drawings
FIG. 1 is a flow chart of an ICP method quantitative determination pre-verification experiment in example 1;
FIG. 2 is a three-dimensional graph of the distribution of the electrode solution content in the battery pole piece after aging for 12 hours in example 1;
FIG. 3 is a three-dimensional graph of the distribution of the electrode solution content in the battery pole piece after aging for 24 hours in example 1;
FIG. 4 is a three-dimensional graph of the distribution of the electrode solution content in the battery pole piece after aging for 48 hours in example 1;
fig. 5 is a distribution diagram of the positions of the spots to be measured on the pole piece in example 1.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments.
Example 1
The embodiment provides a detection method for quantitatively detecting the distribution of electrolyte in a battery, wherein the detection method adopts an electrochemical impedance test and an ICP test and mainly comprises the following three parts:
a first part: ICP method quantitative determination verifies (the purpose of the first part is to verify whether ICP test can accurately evaluate LiPF in electric core6The electrolyte content, all contained in the first part, is not within the scope of the invention and disclosure, but only as a previous work of the technical solution defined by the present invention) as illustrated in fig. 1, includes:
(1) preparing a plurality of positive pole pieces and negative pole pieces, and punching a plurality of circular sample pieces with the diameter of 12mm in a glove box by using a punching machine for later use;
(2) respectively taking 5 positive electrode sample sheets and 5 negative electrode sample sheets, wherein the positive electrode sheets are respectively marked as P1、P2、P3、P4And P5And the negative pole pieces are respectively marked as N1、N2、N3、N4And N5Dripping LiPF with the same mass on each sample wafer by using a liquid-transfering gun6Electrolyte and recording of LiPF drop6The mass of the electrolyte;
(3) all the sample pieces are put in a glove box to be dried until the sample pieces are driedLiPF of6Completely volatilizing the electrolyte;
(4) after air drying, soaking each sample piece in 10mL of aqua regia for 1.5 h;
(5) selecting three groups of positive pole sample pieces (such as P) with better soaking effect1、P2And P5) And three sets of negative electrode test pieces (e.g. N)1、N3And N4) Taking out and storing for later use; carrying out ICP test on the soak solution obtained after soaking the six groups of test pieces to obtain the content of Li element and P element in the soak solution, and reversely deducing LiPF according to the content of Li element and P element6And then calculating to obtain LiPF6The content of the electrolyte, LiPF in the soak solution obtained by soaking the above six groups of test pieces6The electrolyte contents are respectively denoted by mP1，mP2And mP5And mN1，mN3And mN4；
(7) Then the six groups of pole pieces (P) are taken out1、P2、P5、N1、N3And N4) Carrying out secondary soaking to ensure that the electrolyte in each sample piece is completely extracted, carrying out ICP test again, and calculating to obtain LiPF in the soaking solution obtained after each sample piece is soaked6The electrolyte contents, respectively, are denoted by mP1’，mP2’，mP5' and mN1’，mN3' and mN4’；
(8) After adding the results of two ICP tests (e.g. m)P1+mP1') calculating to obtain the electrolyte content in the six groups of sample pieces, and carrying out error analysis on the electrolyte content and the initially dripped electrolyte quality, wherein experiments show that the electrolyte content obtained through ICP testing is very close to the actually dripped electrolyte quality, and the error can be controlled within 5 percent, which indicates that the ICP testing can be used for calculating the electrolyte infiltration state of the full cell.
A second part: ICP legal point detection electric core electrolyte
Taking a sample battery A aged at a high temperature of 45 ℃ for 12 hours after primary liquid injection, disassembling the sample battery A to obtain a battery core, and airing for later use;
(II) respectively taking three positive pole pieces and three negative pole pieces on the upper layer, the middle layer and the lower layer of the battery cell, uniformly selecting 12 point locations to be detected in a half area of each pole piece, cutting each point location to be detected to obtain a circular sample piece with the diameter of 12mm, wherein the distribution area of the point locations to be detected is shown in figure 5;
(III) soaking the sample pieces in 10mL of aqua regia for 1.5h to obtain a soaking solution;
(IV) referring to the step (5) of the first aspect, obtaining the content of Li element and P element in each group of soaking solution through ICP (inductively coupled plasma) test, and reversely deducing LiPF (lithium ion particle Filter) according to the content of Li element and P element6The electrolyte content distribution diagram in the half area of the pole piece is drawn after the integration according to the electrolyte content data in the sample pieces of different point positions to be detected, and the electrolyte content distribution diagram in the half area of the pole piece is directly mirrored to obtain the electrolyte content distribution diagram of the whole pole piece (as shown in figure 2, the 12h aged electrolyte content distribution diagram is shown, the vertical coordinate in figure 2 is the result of normalizing the electrolyte content, namely, the area with the highest electrolyte content in the whole pole piece is marked as 1, and other areas are calculated according to the actual electrolyte content in proportion);
(V) a brand-new sample battery B which is completely the same as the sample battery A in the same batch is selected again, after the sample battery B is aged at the high temperature of 45 ℃ for 24 hours, the steps (I) - (V) are sequentially carried out, and a 24-hour aged battery electrolyte content distribution diagram (shown in figure 3) is obtained; and so on until an electrolyte content profile is obtained for all selected aging times (e.g., the electrolyte content profile tested after 48h of aging is shown in fig. 4).
And a third part: mapping by electrochemical impedance method
(a) Respectively taking a sample battery C (a brand-new battery which is completely the same as the sample battery A in the same batch) with the high-temperature aging time of 12h at the temperature of 45 ℃ after primary liquid injection, carrying out alternating current impedance test, and drawing an alternating current impedance graph under the aging time;
(b) combining the ac impedance diagram of the sample cell C with the electrolyte content distribution diagram of the sample cell a obtained in the second part to obtain a mapping relationship between the ac impedance diagram and the electrolyte content distribution diagram, where the mapping relationship is actually that the ac impedance diagram at each specific aging time corresponds to the electrolyte content distribution diagram at the aging time (of course, since the ac impedance diagram and the electrolyte content distribution diagram are obtained by testing two sample cells respectively, but the two sample cells belong to the same batch and are completely the same, the ac impedance diagram and the electrolyte content distribution diagram can be regarded as being obtained by testing the same cell).
When the electrolyte content distribution condition of other batteries to be tested is tested, only the alternating current impedance of the battery to be tested needs to be tested, and the electrolyte content distribution diagram of the battery to be tested can be obtained by directly contrasting the mapping relation through the alternating current impedance diagram of the battery to be tested.
Example 2
The embodiment provides a detection method for quantitatively detecting the distribution of electrolyte in a battery, wherein the test method adopts a voltage test and an ICP test, and mainly comprises the following three parts:
the first part in this example is exactly the same as the first part in example 1, and the main purpose is to verify whether the ICP test can be used for the test of the electrolyte content;
the second part in this example is also completely the same as the second part in example 1, and the main purpose is to actually test the sample cell by using the ICP method to obtain the electrolyte content distribution maps of the sample cell under different aging times;
the third part of the present embodiment is mapped by using a voltage test, and the difference from the third part of the embodiment 1 is only that the present embodiment uses a voltage test, 8 groups of sample cells are taken, the voltages of the 8 groups of sample cells are tested after a specific aging time, the voltage tests under all selected aging times are summarized, and the averaged voltage values are recorded as the voltage values under the aging time.
And combining the voltage values (obtained from the third part) and the electrolyte content distribution map (obtained from the second part) at each aging time to obtain a mapping relation between the voltage values and the electrolyte content distribution map, wherein the finally obtained mapping relation is that the voltage value at each aging time actually corresponds to the electrolyte content distribution map at a specific same aging time.
When the electrolyte content distribution condition of other batteries to be tested is tested, only the voltage value of the battery to be tested needs to be tested, and the electrolyte content distribution diagram of the battery to be tested can be obtained by directly contrasting the mapping relation with the voltage value of the battery to be tested.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.