阅读说明：本技术 一种锂离子电池不锈钢原材料检验装置及检验方法 (Lithium ion battery stainless steel raw material inspection device and inspection method ) 是由 常海涛 杨鑫 陆行 李治农 于 2021-02-08 设计创作，主要内容包括：本发明提供一种锂离子电池不锈钢原材料检验装置和检验方法,其中检验装置包括由正极壳、负极壳和密封圈组成的密封壳体；所述密封壳体内自下而上依次叠加设置有金属锂片、隔膜和待测的锂离子电池不锈钢原材料片；隔膜完全覆盖金属锂片和锂离子电池不锈钢原材料片设置；所述不锈钢原材料片的上表面与正极壳的内底面接触电连接,所述金属锂片的下表面与负极壳的内底面接触电连接,密封壳体内封装有待测的锂离子电池用电解液；工作时,所述检验装置放置于电化学工作站内并启动电化学工作站的计时电流法程序进行检测。本发明能够实现快速检测不锈钢原材料片与电解液之间的适配性。(The invention provides a device and a method for inspecting stainless steel raw materials of a lithium ion battery, wherein the inspection device comprises a sealing shell consisting of a positive electrode shell, a negative electrode shell and a sealing ring; a metal lithium sheet, a diaphragm and a lithium ion battery stainless steel raw material sheet to be detected are sequentially overlapped in the sealing shell from bottom to top; the diaphragm is arranged to completely cover the metal lithium sheet and the stainless steel raw material sheet of the lithium ion battery; the upper surface of the stainless steel raw material sheet is in contact and electric connection with the inner bottom surface of the positive electrode shell, the lower surface of the metal lithium sheet is in contact and electric connection with the inner bottom surface of the negative electrode shell, and electrolyte for the lithium ion battery to be tested is packaged in the sealed shell; when the device works, the detection device is placed in the electrochemical workstation, and a chronoamperometry program of the electrochemical workstation is started for detection. The invention can realize the rapid detection of the adaptability between the stainless steel raw material sheet and the electrolyte.)

1. The utility model provides a lithium ion battery stainless steel raw and other materials verifying attachment which characterized in that: the sealing structure comprises a sealing shell, wherein the sealing shell consists of an anode shell, a cathode shell and a sealing ring, the anode shell and the cathode shell are both cylindrical, only the lower end of the anode shell is arranged in an open mode, only the upper end of the cathode shell is arranged in an open mode, the anode shell and the cathode shell are arranged in an up-down buckling mode, a gap is reserved between the anode shell and the cathode shell, and the sealing ring is filled in the gap to realize sealing and insulation between the anode shell and the cathode shell; a metal lithium sheet, a diaphragm and a lithium ion battery stainless steel raw material sheet to be detected are sequentially overlapped in the sealing shell from bottom to top; the diaphragm is arranged to completely cover the metal lithium sheet and the stainless steel raw material sheet of the lithium ion battery; the upper surface of the lithium ion battery stainless steel raw material sheet is in contact and electric connection with the inner bottom surface of the positive electrode shell, the lower surface of the metal lithium sheet is in contact and electric connection with the inner bottom surface of the negative electrode shell, the electrolyte for the lithium ion battery to be tested is packaged in the inner cavity of the cylinder of the sealed shell, and the lithium ion battery stainless steel raw material sheet, the diaphragm and the metal lithium sheet are all soaked in the electrolyte; the positive electrode shell and the negative electrode shell are made of the same material as the stainless steel raw material sheet of the lithium ion battery; when the device works, the detection device is placed in the electrochemical workstation, and a chronoamperometry program of the electrochemical workstation is started for detection.

2. The lithium ion battery stainless steel raw material inspection device of claim 1, wherein a conductive column, a lithium ion battery stainless steel raw material sheet to be inspected, a diaphragm and a lithium metal sheet are sequentially stacked from top to bottom in the sealing housing, the upper surface of the conductive column is in contact and electrical connection with the inner bottom surface of the positive electrode shell, the lower surface of the lithium metal sheet is in contact and electrical connection with the inner bottom surface of the negative electrode shell, and the conductive column at least meets one of the following two conditions: (1) the conductive column is made of a material which does not chemically react with the electrolyte for the lithium ion battery to be tested; (2) the conducting posts are made of conducting posts with the same material as the stainless steel raw material sheet of the lithium ion battery to be tested.

3. The lithium ion battery stainless steel raw material inspection device of claim 2, characterized in that: the conductive posts are hard conductive posts.

4. The lithium ion battery stainless steel raw material inspection device of claim 2, characterized in that: the conductive column is a cylindrical structure formed by winding an aluminum foil.

5. A method for inspecting a lithium ion battery stainless steel raw material is characterized by comprising the following steps: firstly assembling a lithium ion battery stainless steel raw material inspection device as defined in any one of claims 1 to 4; then the testing device is placed in an electrochemical workstation, and the anode and the cathode of the electrochemical workstation are respectively and electrically connected with the outer bottom surfaces of the anode and cathode shells of the testing device; finally, starting a timing current method program on the electrochemical workstation to detect the inspection device, displaying a change curve of current along with time on a display of the electrochemical workstation, corroding the stainless steel raw material of the lithium ion battery when the current fluctuates along with the increase of the time, and adapting the stainless steel raw material of the lithium ion battery to be detected to the electrolytic liquid for the lithium ion battery to be detected; when the current does not fluctuate along with the increase of time, the stainless steel raw material of the lithium ion battery is not corroded, and the stainless steel raw material of the lithium ion battery to be detected is not matched with the electrolyte for the lithium ion battery to be detected.

Technical Field

The invention relates to the field of batteries, in particular to a device and a method for inspecting stainless steel raw materials of a lithium ion battery.

Background

Different types of electrolyte have different corrosion effects on stainless steel of different models, so that the traditional steel shell battery is influenced by external temperature and battery voltage after being stored for a long time, the corrosion of the electrolyte on the steel shell of the battery is accelerated, and the phenomenon of short circuit inside the battery is caused. Therefore, the corrosion degree of stainless steel with different types in different types of electrolyte can seriously affect the performance of the battery, and the failure condition of the battery in the long-term use process can bring extremely poor use feeling to customers. At the same time, this is certainly the largest loss for the manufacturing enterprise.

The selection of different types of battery electrolyte models and stainless steel shells is crucial, most enterprises can select the stainless steel model of the battery shell according to the recommendation of stainless steel manufacturers and routine experience when facing how batteries are matched with different types of stainless steel, but irreparable loss is caused once the selected stainless steel model is not matched with the electrolyte. Some battery manufacturers can judge the suitability between the electrolyte and the battery steel shell by firstly manufacturing a complete battery, then storing the complete battery for a long time (30 days) in a specific temperature environment (normal temperature or 45 ℃), and then testing whether the voltage of the battery is obviously reduced or splitting the battery to check the internal corrosion condition of the battery, but the time period is too long, so that the corresponding change can not be quickly made along with the change of the market in the new product development process.

In addition, there is also a "method for measuring a metal corrosion rate by a tafel curve (also referred to as a" tafel curve ") in the related art, specifically: pouring the electrolyte into an electrolytic cell, then putting a steel sheet to be detected as a working electrode, saturated calomel as a reference electrode and platinum as a counter electrode to form a tafel detection electrochemical system based on three electrodes. However, the electrolytic cell of the electrochemical system of the method is difficult to be absolutely sealed, and for the lithium ion battery, the water content of the electrolyte is generally required to be below 50ppm, so the existing tafel detection electrochemical system is not suitable for the test of the electrolyte of the lithium ion battery; meanwhile, when the tab detection electrochemical system is used for testing in an electrochemical workstation, parameter setting is required, and the operation is complex.

Therefore, the device and the method for rapidly detecting the corrosion resistance of the stainless steel raw materials of the lithium ion batteries of different models to the electrolyte are of great significance.

Disclosure of Invention

One of the objectives of the present invention is to provide a lithium ion battery stainless steel raw material inspection device, which is placed in an electrochemical workstation to perform a "potentiometric step-timing coulometry (also referred to as" chronoamperometry ")" test, so as to determine whether a stainless steel raw material sheet in the inspection device is corroded according to whether a current value fluctuates with time in a test result, thereby rapidly detecting suitability between the stainless steel raw material sheet and an electrolyte in the inspection device.

A lithium ion battery stainless steel raw material inspection device comprises a sealing shell, wherein the sealing shell consists of a positive electrode shell, a negative electrode shell and a sealing ring, the positive electrode shell and the negative electrode shell are both cylindrical, only the lower end of the positive electrode shell is arranged in an open mode, only the upper end of the negative electrode shell is arranged in an open mode, the positive electrode shell and the negative electrode shell are arranged in a buckled mode from top to bottom, a gap is reserved between the positive electrode shell and the negative electrode shell, and the sealing ring is filled in the gap to achieve sealing and insulation between the positive electrode shell and the negative electrode shell; a metal lithium sheet, a diaphragm and a lithium ion battery stainless steel raw material sheet to be detected are sequentially overlapped in the sealing shell from bottom to top; the diaphragm is arranged to completely cover the metal lithium sheet and the stainless steel raw material sheet of the lithium ion battery, so that the diaphragm can completely separate the metal lithium sheet from the stainless steel raw material sheet of the lithium ion battery; the upper surface of the lithium ion battery stainless steel raw material sheet is in contact and electric connection with the inner bottom surface of the positive electrode shell, the lower surface of the metal lithium sheet is in contact and electric connection with the inner bottom surface of the negative electrode shell, the electrolyte for the lithium ion battery to be tested is packaged in the inner cavity of the cylinder of the sealed shell, and the lithium ion battery stainless steel raw material sheet, the diaphragm and the metal lithium sheet are all soaked in the electrolyte; the positive electrode shell and the negative electrode shell are made of the same material as the stainless steel raw material sheet of the lithium ion battery; when the device works, the detection device is placed in the electrochemical workstation, and a chronoamperometry program of the electrochemical workstation is started for detection.

Chronoamperometry is a simple and widely used electrochemical detection technique. The working principle is as follows: a step potential is applied as an excitation between a working electrode and a reference electrode of an electrochemical system, a time-varying response current generated by a redox reaction flows through the working electrode and the counter electrode, and the current response is measured as a function of time. However, the chronoamperometry is currently used only for electrochemical studies, i.e., electron transfer kinetics studies.

The lithium ion battery stainless steel raw material inspection device is a timing current method detection system, because the voltage of metal lithium is usually lower than that of stainless steel, a metal lithium sheet is used as a reference electrode and a counter electrode and is in contact and electric connection with a negative electrode shell, and because the voltage (3.9V) of the metal lithium is basically consistent with the voltage (3.9V) of the lithium ion battery in a storage state, the metal lithium sheet is used as the reference electrode, and the storage state of the lithium ion battery can be simulated; meanwhile, the stainless steel material sheet of the lithium ion battery is used as a working electrode and is in contact electrical connection with the positive electrode shell; in addition, the metal lithium sheet, the lithium ion battery stainless steel raw material sheet to be detected and the lithium ion electrolyte to be detected are sealed in the sealed shell through the sealed shell, so that the lithium ion electrolyte is prevented from being polluted by moisture in the air; the testing device is placed in the electrochemical workstation, and a timing current method testing system of the electrochemical workstation is started to test, the timing current method testing system of the electrochemical workstation can directly measure and give a function relation curve of current and time, whether the stainless steel raw material sheet to be tested in the testing device is corroded is judged by observing whether the current value fluctuates along with the increase of time, and therefore the adaptability between the stainless steel raw material of the lithium ion battery to be tested and the electrolyte for the lithium ion battery to be tested in a normal storage state can be rapidly and visually judged; in addition, the positive electrode shell and the negative electrode shell are made of the same material as the stainless steel raw material sheet of the lithium ion battery, so that the current test results generated between two different stainless steel products and electrolyte are inconsistent and mutually confused when the materials of the positive electrode shell and the stainless steel raw material sheet of the lithium ion battery are different, and the accuracy of the test results is influenced; the device is a two-electrode system, has simple structure, easy operation and good tightness, and the test result of the chronoamperometry is more intuitive, thereby realizing the purpose of quickly judging the suitability between the stainless steel raw material and the electrolyte.

Preferably, top-down superposes in proper order in the sealed casing and is provided with and leads electrical pillar, the lithium ion battery stainless steel raw materials tablet, diaphragm and the metal lithium piece that awaits measuring, the upper surface that leads electrical pillar is connected with the interior bottom surface contact electricity of positive plate shell, and the lower surface of metal lithium piece is connected with the interior bottom surface contact electricity of negative plate shell, it satisfies one of following two conditions at least to lead electrical pillar: (1) the conductive column is made of a material which does not chemically react with the electrolyte for the lithium ion battery to be tested; (2) the conducting posts are made of conducting posts with the same material as the stainless steel raw material sheet of the lithium ion battery to be tested. The conductive column plays a role in conducting electricity between the lithium ion battery stainless steel raw material sheet and the positive electrode shell, and plays a role in enabling the metal lithium sheet, the diaphragm and the stainless steel sheet to be in closer contact when the lithium ion battery stainless steel raw material sheet is thinner; in order to avoid the influence of the chemical reaction between the conductive post and the electrolyte on the test result, the conductive post needs to be made of a material which does not chemically react with the electrolyte or made of a material which is the same as that of the stainless steel raw material sheet of the lithium ion battery. The conducting posts are preferably hard conducting posts, and can play a role in enabling metal lithium, the diaphragm and the stainless steel sheet to be in close contact. Furthermore, the conductive column is preferably a cylindrical structure formed by winding an aluminum foil, and the conductive column is made of the same material as the battery tab, so that additional materials do not need to be purchased.

The invention also aims to provide a method for inspecting the stainless steel raw material of the lithium ion battery, which comprises the following steps: firstly, assembling the lithium ion battery stainless steel raw material inspection device; then the testing device is placed in an electrochemical workstation, and the anode and the cathode of the electrochemical workstation are respectively and electrically connected with the outer bottom surfaces of the anode and cathode shells of the testing device; finally, starting a timing current method program on the electrochemical workstation to detect the inspection device, displaying a change curve of current along with time on a display of the electrochemical workstation, corroding the stainless steel raw material of the lithium ion battery when the current fluctuates along with the increase of the time, and adapting the stainless steel raw material of the lithium ion battery to be detected to the electrolytic liquid for the lithium ion battery to be detected; when the current does not fluctuate along with the increase of time, the stainless steel raw material of the lithium ion battery is not corroded, and the stainless steel raw material of the lithium ion battery to be detected is not matched with the electrolyte for the lithium ion battery to be detected.

Drawings

Fig. 1 is an axial cross-sectional structural view of a lithium ion battery stainless steel raw material inspection device according to any one of embodiments 1 to 4;

FIG. 2 is a graph showing the change of current with time measured by chronoamperometry in the inspection apparatus for stainless steel raw material for lithium ion batteries of example 1;

FIG. 3 is a microscopic view of a stainless steel raw material sheet in the lithium ion battery stainless steel raw material inspection device of example 1 after chronoamperometry testing;

FIG. 4 is a graph showing the change of current with time measured by chronoamperometry in the inspection apparatus for stainless steel raw material for lithium ion battery of example 2;

FIG. 5 is a microscopic view of a stainless steel raw material sheet in the lithium ion battery stainless steel raw material inspection device of example 2 after chronoamperometry testing;

FIG. 6 is a graph showing the change of current with time measured by chronoamperometry in the inspection apparatus for stainless steel raw materials for lithium ion batteries of examples 3 and 4;

FIG. 7 is a microscopic view of a stainless steel raw material sheet in the lithium ion battery stainless steel raw material inspection device of example 3 after chronoamperometry testing;

FIG. 8 is a microscopic view of a stainless steel raw material sheet in the lithium ion battery stainless steel raw material inspection device of example 4 after chronoamperometry testing;

FIG. 9 is a sectional view in the axial direction of the inspection apparatus for a stainless steel raw material for a lithium ion battery according to example 5;

fig. 10 is a top view structural view of the conductive post.

Detailed Description

The 5 embodiments of the present invention will now be described in detail:

example 1

As shown in fig. 1, a lithium ion battery stainless steel raw material inspection device comprises a sealing shell 1, wherein the sealing shell 1 is composed of a positive electrode shell 11, a negative electrode shell 12 and a sealing ring 13, wherein both the positive electrode shell 11 and the negative electrode shell 12 are cylindrical, only the lower end of the positive electrode shell 11 is open, only the upper end of the negative electrode shell 12 is open, the positive electrode shell and the negative electrode shell (11, 12) are buckled up and down, a gap is reserved between the positive electrode shell and the negative electrode shell (11, 12), and the sealing ring 13 is filled in the gap to realize the sealing and insulation between the positive electrode shell and the negative electrode shell (11, 12); a metal lithium sheet 2, a diaphragm 3, a lithium ion battery stainless steel raw material sheet 4 to be tested and a conductive column 6 are sequentially stacked in the sealed shell 1 from bottom to top; the conductive posts 6 are made of materials which do not chemically react with the electrolyte 5 for the lithium ion battery to be tested; the diaphragm 3 is arranged to completely cover the metal lithium sheet 2 and the lithium ion battery stainless steel raw material sheet 4, so that the diaphragm 3 can completely separate the metal lithium sheet 2 from the lithium ion battery stainless steel raw material sheet 4; the conductive column 6 is in contact electrical connection with the inner bottom surface of the positive electrode shell 11, the metal lithium sheet 2 is in contact electrical connection with the inner bottom surface of the negative electrode shell 12, the electrolyte 5 for the lithium ion battery to be tested is packaged in the inner cavity of the cylinder body of the sealed shell 1, and the stainless steel raw material sheet 4, the diaphragm 3 and the metal lithium sheet 2 of the lithium ion battery are all soaked in the electrolyte 5; the positive electrode shell and the negative electrode shell (11, 12) are both made of the same stainless steel material sheet 4 of the lithium ion battery; in operation, the test device is placed in an electrochemical workstation (of conventional construction, not shown) and the chronoamperometric procedure of the electrochemical workstation is initiated for detection;

the lithium ion battery stainless steel raw material sheet 4 to be tested is a 304 stainless steel sheet, and the lithium ion battery electrolyte 5 to be tested is K01 electrolyte.

A method for inspecting a lithium ion battery stainless steel raw material comprises the following steps: firstly, assembling the lithium ion battery stainless steel raw material inspection device; then the testing device is placed in an electrochemical workstation, and the anode and the cathode of the electrochemical workstation are respectively and electrically connected with the outer bottom surfaces of the anode and cathode shells of the testing device; finally, starting a timing current method program on the electrochemical workstation to detect the inspection device, displaying a change curve of current along with time on a display of the electrochemical workstation, corroding the stainless steel raw material of the lithium ion battery when the current fluctuates along with the increase of the time, and adapting the stainless steel raw material of the lithium ion battery to be detected to the electrolytic liquid for the lithium ion battery to be detected; when the current does not fluctuate along with the increase of time, the stainless steel raw material of the lithium ion battery is not corroded, and the stainless steel raw material of the lithium ion battery to be detected is not matched with the electrolyte for the lithium ion battery to be detected.

The test result of the lithium ion battery stainless steel raw material inspection device in example 1 after being placed in an electrochemical workstation under normal temperature and tested by a chronoamperometry is shown in fig. 2, and the current-time change curve in fig. 2 is observed to show that: the current continuously decreases and fluctuates along with the increase of time, which indicates that when 304 stainless steel is used as a lithium ion battery stainless steel raw material (for manufacturing a pole shell) and K01 electrolyte is used as the electrolyte for the lithium ion battery to assemble the lithium ion battery, the stainless steel pole shell and the electrolyte are in contact to generate a corrosion reaction under the normal temperature condition.

Meanwhile, the applicant detaches the testing device tested by the chronoamperometry, and observes the surface of the lithium ion battery stainless steel raw material sheet 4 to be tested in the battery through a microscope, and the observation result is shown in fig. 3, and can be clearly seen in fig. 3: the surface of the lithium ion battery stainless steel raw material sheet 4 to be tested does have a plurality of corrosion spots.

Therefore, the 304 stainless steel raw material is not compatible with the K01 electrolyte at normal temperature.

Example 2

The lithium ion battery stainless steel raw material inspection device and the inspection method of the embodiment 2 are different from the embodiment in that: the lithium ion battery stainless steel raw material sheet 4 to be tested is a 316L stainless steel sheet, and the lithium ion battery electrolyte 5 to be tested is K01 electrolyte.

The test result of the lithium ion battery stainless steel raw material inspection device of example 2 after being placed in an electrochemical workstation under normal temperature and tested by a chronoamperometry is shown in fig. 4, and it can be seen by observing the current-time change curve in fig. 4 that: the current does not fluctuate with the increase of time, which indicates that when 316L stainless steel is used as a stainless steel raw material (for manufacturing a pole shell) of the lithium ion battery and K01 electrolyte is used as electrolyte for the lithium ion battery to assemble the lithium ion battery, the stainless steel pole shell is not in contact with the electrolyte and has no corrosion reaction under the normal temperature condition.

Meanwhile, the applicant detaches the testing device tested by the chronoamperometry, and observes the surface of the lithium ion battery stainless steel raw material sheet 4 to be tested in the battery through a microscope, and the observation result is shown in fig. 5, and can be clearly seen in fig. 3: no corrosion spots appear on the surface of the lithium ion battery stainless steel raw material sheet 4 to be detected.

Therefore, the 316L stainless steel raw material was compatible with the K01 electrolyte at normal temperature.

Example 3

The lithium ion battery stainless steel raw material inspection device and the inspection method of the embodiment 3 are different from the embodiment in that: the lithium ion battery stainless steel raw material sheet 4 to be tested is a 304 stainless steel sheet, and the electrolyte 5 for the lithium ion battery to be tested is E2656 electrolyte.

The test result of the lithium ion battery stainless steel raw material inspection device of example 3 after being placed in the electrochemical workstation at 45 ℃ and tested by the chronoamperometry is shown in fig. 6, and it can be seen by observing the current-time change curve corresponding to "45 ℃ -304" in fig. 6: the current obviously fluctuates along with the increase of time, which indicates that when the 304 stainless steel is used as the raw material of the lithium ion battery stainless steel (for manufacturing the pole shell) and the E2656 electrolyte is used as the electrolyte for the lithium ion battery to assemble the lithium ion battery, the stainless steel pole shell and the electrolyte are in contact to generate corrosion reaction at the temperature of 45 ℃.

Meanwhile, the applicant detaches the testing device tested by the chronoamperometry, and observes the surface of the lithium ion battery stainless steel raw material sheet 4 to be tested in the battery through a microscope, and the observation result is shown in fig. 7, and can be clearly seen in fig. 3: a plurality of corrosion spots appear on the surface of the lithium ion battery stainless steel raw material sheet 4 to be detected.

Therefore, the 304 stainless steel raw material is not compatible with the E2656 electrolyte at a temperature of 45 ℃.

Example 4

The lithium ion battery stainless steel raw material inspection device and the inspection method of the embodiment 4 are different from the embodiment in that: the lithium ion battery stainless steel raw material sheet 4 to be tested is a 316L stainless steel sheet, and the electrolyte 5 for the lithium ion battery to be tested is E2656 electrolyte.

The test result of the lithium ion battery stainless steel raw material inspection device of example 4 after being placed in the electrochemical workstation at 45 ℃ and tested by the chronoamperometry is shown in fig. 6, and it can be seen by observing the current-time change curve corresponding to "45 ℃ -316" in fig. 6: the current does not fluctuate basically with the increase of time, which shows that when 316L stainless steel is used as the raw material of the lithium ion battery stainless steel (for manufacturing the pole shell) and E2656 electrolyte is used as the electrolyte for the lithium ion battery to assemble the lithium ion battery, the stainless steel pole shell is not in contact with the electrolyte to generate corrosion reaction at the temperature of 45 ℃.

Meanwhile, the applicant detaches the testing device tested by the chronoamperometry, and observes the surface of the lithium ion battery stainless steel raw material sheet 4 to be tested in the battery through a microscope, and the observation result is as shown in fig. 8, and can be observed in fig. 8: no corrosion spots appear on the surface of the lithium ion battery stainless steel raw material sheet 4 to be detected.

Thus, the 316L stainless steel raw material was matched to the E2656 electrolyte at a temperature of 45 ℃.

In the foregoing lithium ion battery stainless steel raw material inspection devices in embodiments 1 to 4, the sealing case 1 is provided with the conductive posts 6 therein, and the conductive posts 6 are in contact with and electrically connected to the inner bottom surface of the positive electrode case 11. However, in practice, the sealing housing 1 of the present invention may not have the conductive posts 6, and when the thickness of the lithium ion battery stainless steel raw material sheet 4 to be measured is thick enough, so that the total thickness of the lithium metal sheet 2, the diaphragm 3, and the lithium ion battery stainless steel raw material sheet 4 to be measured is equal to the height of the inner cavity of the sealing housing 1, the conductive posts 6 may not be provided. The present inventors also made an experiment without providing the conductive post 6 (i.e., embodiment 5).

Example 5

The lithium ion battery stainless steel raw material inspection apparatus and the inspection method of example 5 are different from those of example 2 in that: a metal lithium sheet 2, a diaphragm 3 and a lithium ion battery stainless steel raw material sheet 4 to be tested are sequentially stacked in the sealed shell 1 from bottom to top; the lithium ion battery stainless steel raw material sheet 4 is in contact and electric connection with the inner bottom surface of the positive electrode shell 11.

The lithium ion battery stainless steel raw material inspection device of example 5 was placed in an electrochemical workstation at normal temperature for test results after a chronoamperometry test: the current does not fluctuate as time increases. Consistent with the test results of example 2.

The electrolyte solutions K01 and E2656 used in examples 1 to 3 were commercially available, wherein the electrolyte solution E2656 was obtained from the company having high new materials, granted, guangzhou, and the electrolyte solution K01 was obtained from the company having new energy materials, science and technology, granted, kyo, western science and technology.

In examples 1 to 5, the conductive post 6 has a cylindrical structure formed by winding an aluminum foil. The aluminum does not chemically react with the electrolyte 5 for the lithium ion battery. However, the conductive post 6 of the present invention is not limited to a cylindrical structure wound with aluminum foil, and may be a cylindrical aluminum ingot or other conductive post that does not chemically react with the electrolyte, other than aluminum. Of course, the conductive posts of the present invention may also be conductive posts made of the same material as the lithium ion battery stainless steel raw material sheet 4 to be tested.

The lithium ion battery stainless steel raw material inspection device is a timing current method detection system, because the voltage of metal lithium is usually lower than that of stainless steel, the metal lithium sheet 2 is used as a reference electrode and a counter electrode and is in contact and electric connection with the negative electrode shell 12, and because the voltage (3.9V) of the metal lithium is basically consistent with the voltage (3.9V) of the lithium ion battery in the storage state, the metal lithium sheet 2 is used as the reference electrode, and the storage state of the lithium ion battery can be simulated; meanwhile, the lithium ion battery stainless steel raw material sheet 4 to be tested is used as a working electrode and is in contact and electric connection with the positive electrode shell 11; in addition, the metal lithium sheet 2, the lithium ion battery stainless steel raw material sheet 4 and the lithium ion electrolyte 5 are sealed in the sealed shell 1 through the sealed shell 1, so that the lithium ion electrolyte is prevented from being polluted by moisture in the air; the testing device is placed in the electrochemical workstation, and a timing current method testing system of the electrochemical workstation is started to test, the timing current method testing system of the electrochemical workstation can directly measure and give a function relation curve of current and time, whether the stainless steel raw material sheet in the testing device is corroded is judged by observing whether the current value fluctuates along with the increase of time, and the adaptability between the lithium ion battery stainless steel raw material and the electrolyte in a normal storage state is rapidly and visually judged; in addition, the positive electrode shell and the negative electrode shell (11 and 12) are both selected from the positive electrode shell and the negative electrode shell which are the same as the lithium ion battery stainless steel raw material sheet 4 to be tested, so that the problem that when the materials of the electrode shell and the lithium ion battery stainless steel raw material sheet 4 are different, current test results generated between two different stainless steel products and the lithium ion electrolyte 5 to be tested are inconsistent and mutually confused to influence the accuracy of the test results is avoided; the device is a two-electrode system, has simple structure, easy operation and good tightness, and the test result of the chronoamperometry is more intuitive, thereby realizing the purpose of quickly judging the suitability between the stainless steel raw material and the electrolyte.

The lithium ion battery stainless steel raw material inspection device and the inspection method of the embodiments 1-4 of the invention can be improved as follows: the conductive column 6 is preferably a hard conductive column, and can play a role in making the lithium metal sheet 2, the diaphragm 3 and the stainless steel raw material sheet 4 contact more closely.