Method and device for testing corrosion resistance of electrolytic copper foil for lithium ion battery

Abstract

The invention discloses a method and a device for testing corrosion resistance of an electrolytic copper foil for a lithium ion battery, and belongs to the technical field of material performance tests.The method comprises the following steps: carrying out a corrosion test on the electrolytic copper foil, obtaining test data of the electrolytic copper foil in the corrosion test, and generating a corrosion speed score; acquiring corrosion state data of the electrolytic copper foil in a corrosion stagnation stage; according to the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnant time point, generating a corrosion degree score; classifying the corrosion resistance of the electrolytic copper foil according to the corrosion speed score and the corrosion degree score; according to the method, the corrosion area and the corrosion depth of the electrolytic copper foil are obtained during the anti-corrosion test of the electrolytic copper foil, the corrosion starting time and the corrosion stagnation time are obtained, and the corrosion resistance of the electrolytic copper foil is comprehensively analyzed by combining the corrosion state of the electrolytic copper foil after the corrosion stagnation stage, so that the corrosion resistance of the electrolytic copper foil is quantified; and the test result of the anti-corrosion test of the electrolytic copper foil is more comprehensive.

Description

Technical Field

[0001] The present invention belongs to the technical field of material performance testing, and in particular relates to a method and device for testing the corrosion resistance of electrolytic copper foil for lithium-ion batteries. Background Art

[0002] Electrolytic copper foil, as the negative electrode current collector of lithium-ion batteries, plays the role of electron conductivity during the battery's charge and discharge process; it connects the negative electrode material (usually graphite) to the battery's external circuit to ensure the smooth flow of current; electrolytic copper foil will come into contact with the electrolyte in the working environment of the lithium-ion battery, especially during the battery cycle, and may cause certain corrosion problems; corrosion not only affects the conductivity of the copper foil, but may also cause the battery performance to decline and even cause safety issues; therefore, copper foil needs to have good corrosion resistance to prevent excessive corrosion during long-term use.

[0003] In the existing technology, the methods for testing the corrosion resistance of electrolytic copper foil include electrochemical testing, immersion testing, salt spray testing, etc.; however, in the existing testing methods, the corrosion assessment of copper foil mainly relies on a single static indicator, such as the final corrosion area or weight loss rate; the corrosion rate change process (such as the corrosion start time and the passivation film formation time) is not quantified, and the real-time degradation mechanism of the material in the battery electrolyte environment cannot be reflected, thereby reducing the comprehensiveness of the test results of electrolytic copper foil in corrosion resistance testing. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method and device for testing the corrosion resistance of electrolytic copper foil for lithium-ion batteries, which solves the above problems.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries, comprising the following steps: Conducting a corrosion test on the electrolytic copper foil to obtain test data of the electrolytic copper foil in the corrosion test; wherein the test data includes corrosion area, corrosion depth, corrosion start time, and corrosion stagnation time; Generate a corrosion rate score based on the test data of the electrolytic copper foil in the corrosion test; Obtaining corrosion status data of the electrolytic copper foil during the corrosion stagnation stage; wherein the corrosion status data includes the stagnation corrosion area and the stagnation corrosion depth; Generate a corrosion degree score based on the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnation time point; The corrosion resistance of electrolytic copper foil is classified according to the corrosion rate score and corrosion degree score.

[0006] On the basis of the above technical solutions, the present invention also provides the following optional technical solutions: Further technical solution: The method for obtaining the corrosion stagnation time is specifically as follows: The corrosion area and corrosion depth of the electrolytic copper foil obtained each time are screened; wherein the screening method is specifically: removing the corrosion area and corrosion depth of the electrolytic copper foil before the corrosion start time; The corrosion area and corrosion depth of the electrolytic copper foil obtained each time are arranged in time sequence to generate a corrosion area dataset and a corrosion depth dataset; The corrosion area dataset and the corrosion depth dataset are respectively used to generate the corrosion area change curve and the corrosion depth change curve in time sequence; Substitute the corrosion area change curve and the corrosion depth change curve into the same two-dimensional coordinate system to obtain a line segment in the corrosion area change curve and the corrosion depth change curve that is nearly parallel to the X-axis of the coordinate system. The starting point of the line segment is the corrosion stagnation time.

[0007] Further technical solution: The corrosion rate score is generated in the following manner: Generate the corrosion start duration according to the corrosion start time; the corrosion start duration refers to the time from the start of the corrosion test to the corrosion start time; Generate a corrosion start speed score based on the corrosion start time; the corrosion start speed score refers to the ratio of the corrosion start time to the standard corrosion start time; Generate the passivation film formation time according to the corrosion stagnation time; the passivation film formation time refers to the time from the start of corrosion to the corrosion stagnation time; Generate a passivation film forming speed score based on the passivation film forming time; wherein the passivation film forming speed score refers to the ratio between the passivation film forming time and the standard passivation film forming time; A corrosion rate score is generated based on the corrosion start rate score and the passive film formation rate score; wherein the corrosion rate score refers to the sum of the corrosion start rate score and the passive film formation rate score.

[0008] Further technical solution: The method for generating the corrosion degree score specifically includes: The surface corrosion rate is generated based on the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation time point; wherein the surface corrosion rate refers to the ratio between the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation stage and the surface area of the electrolytic copper foil; According to the stagnation corrosion depth of the electrolytic copper foil in the corrosion stagnation stage, a deep corrosion rate is generated; wherein the deep corrosion rate refers to the ratio between the stagnation corrosion depth of the electrolytic copper foil in the corrosion stagnation stage and the thickness of the electrolytic copper foil; A corrosion severity score is generated based on the surface corrosion rate and deep corrosion rate.

[0009] Further technical solution: The corrosion degree score is generated based on the surface corrosion rate and the deep corrosion rate, specifically: By formula: ; Generate corrosion severity score K s ; In the formula, C a " It represents the surface corrosion rate threshold, C d " It represents the deep corrosion rate threshold, C a It represents the surface corrosion rate, C d It represents the deep corrosion rate, a1 and a2 are weight coefficients, and a1+a2=1.

[0010] Further technical solution: The method of classifying the corrosion resistance of electrolytic copper foil includes: Generate a corrosion resistance score based on the corrosion rate score and the corrosion severity score; the corrosion resistance score refers to the difference between the corrosion rate score and the corrosion severity score; The corrosion resistance of electrolytic copper foil is classified according to the corrosion resistance score.

[0011] A corrosion resistance testing device for electrolytic copper foil for lithium-ion batteries, the device specifically comprising: Test assembly for performing corrosion tests on electrolytic copper foil; A test data acquisition component is used to obtain test data of the electrolytic copper foil in the corrosion test; wherein the test data includes corrosion area, corrosion depth, corrosion start time and corrosion stagnation time; A test data analysis unit, used to generate a corrosion rate score based on the test data of the electrolytic copper foil in the corrosion test; A state data acquisition unit is used to acquire corrosion state data of the electrolytic copper foil during the corrosion stagnation stage; wherein the corrosion state data includes the stagnation corrosion area and the stagnation corrosion depth; A state analysis unit is used to generate a corrosion degree score based on the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnation time point; The comprehensive analysis unit is used to classify the corrosion resistance of the electrolytic copper foil according to the corrosion rate score and the corrosion degree score; wherein the classification types include primary corrosion resistance, secondary corrosion resistance and tertiary corrosion resistance.

[0012] Further technical solution: The test data analysis unit specifically includes: The corrosion start duration generation module is used to generate the corrosion start duration according to the corrosion start time; wherein the corrosion start duration refers to the time from the start of the corrosion test to the corrosion start time; The corrosion onset time analysis module is used to generate a corrosion onset speed score based on the corrosion onset time. The corrosion onset speed score refers to the ratio of the corrosion onset time to the standard corrosion onset time. The passivation film formation time generation module is used to generate the passivation film formation time according to the corrosion stagnation time; wherein the passivation film formation time refers to the time from the start time of corrosion to the corrosion stagnation time; A passivation film forming speed analysis module is used to generate a passivation film forming speed score based on the passivation film forming time; wherein the passivation film forming speed score refers to the ratio between the passivation film forming time and the standard passivation film forming time; The corrosion rate score generating module is used to generate a corrosion rate score according to the starting corrosion rate score and the passivation film forming rate score; wherein the corrosion rate score refers to the sum of the starting corrosion rate score and the passivation film forming rate score.

[0013] Further technical solution: The state analysis unit specifically includes: The surface corrosion rate analysis module is used to generate a surface corrosion rate based on the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation time point; the surface corrosion rate refers to the ratio between the stagnant corrosion area of the electrolytic copper foil during the corrosion stagnation stage and the surface area of the electrolytic copper foil; A deep corrosion rate analysis module is used to generate a deep corrosion rate based on the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage; wherein the deep corrosion rate refers to the ratio between the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage and the thickness of the electrolytic copper foil; The corrosion degree score generating module is used to generate a corrosion degree score according to the surface corrosion rate and the deep corrosion rate.

[0014] Further technical solution: The comprehensive analysis unit specifically includes: A comprehensive analysis module is used to generate a corrosion resistance score based on the corrosion rate score and the corrosion severity score; wherein the corrosion resistance score is the difference between the corrosion rate score and the corrosion severity score; The evaluation module is used to classify the corrosion resistance of the electrolytic copper foil according to the corrosion resistance score.

[0015] The present invention provides a method and device for testing the corrosion resistance of electrolytic copper foil for lithium-ion batteries, which has the following advantages compared with the prior art: The present invention obtains the corrosion area and corrosion depth of the electrolytic copper foil during the corrosion resistance test of the electrolytic copper foil, obtains the corrosion start time and the corrosion stagnation time, and then combines the corrosion state of the electrolytic copper foil after the corrosion stagnation stage to comprehensively analyze the corrosion resistance of the electrolytic copper foil, thereby quantifying the corrosion resistance of the electrolytic copper foil and making the test results of the corrosion resistance test of the electrolytic copper foil more comprehensive. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flowchart of a method for testing the corrosion resistance of electrolytic copper foil for lithium-ion batteries provided in an embodiment of the present invention.

[0017] Figure 2 This is a flowchart of step 2 provided in an embodiment of the present invention.

[0018] Figure 3 This is a flowchart of step 4 provided in an embodiment of the present invention.

[0019] Figure 4 This is a flowchart of step 5 provided in an embodiment of the present invention.

[0020] Figure 5 This is a flow chart of a device for testing the corrosion resistance of electrolytic copper foil for lithium-ion batteries provided by an embodiment of the present invention.

[0021] Figure 6 This is a module block diagram of a test data analysis unit provided in an embodiment of the present invention.

[0022] Figure 7 This is a module block diagram of a status analysis unit provided in an embodiment of the present invention.

[0023] Figure 8 This is a module block diagram of a comprehensive analysis unit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0026] See also Figure 1 , a method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries provided by one embodiment of the present invention, comprising the following steps: Step 1: Conduct a corrosion test on the electrolytic copper foil to obtain test data of the electrolytic copper foil in the corrosion test; wherein the test data includes corrosion area, corrosion depth, corrosion start time, and corrosion stagnation time; It should be noted that the corrosion start time refers to the time when the electrolytic copper foil begins to corrode; the corrosion stagnation time refers to the time when the corrosion rate of the electrolytic copper foil slows down or stagnates; in addition, the slow rate refers to the rate close to the corrosion stagnation; Specifically, corrosion tests on electrolytic copper foil include but are not limited to electrochemical corrosion tests, immersion corrosion tests, and salt spray corrosion tests. In addition, in corrosion tests such as electrochemical corrosion tests, immersion corrosion tests, and salt spray corrosion tests, the electrolytic copper foil will show corrosion area and corrosion depth. For example, in the immersion corrosion test of electrolytic copper foil for lithium-ion electronics, the immersion solution used is a mixture of a lithium salt solution (such as LiPF6, LiBF4, etc.) and an organic solvent. A common ratio may be 1M LiPF6 dissolved in a 1:1 mixture of dimethyl carbonate (DMC) and ethylene carbonate (EC). In this embodiment, the corrosion area of the electrolytic copper foil during the corrosion test can be obtained using image vision technology. For example, during the immersion corrosion process, high-resolution imaging of the copper foil surface is performed at regular intervals using a scanning electron microscope (SEM). SEM images with different magnifications are used to obtain the corrosion conditions of different areas. The surface morphology before and after corrosion is then compared to calculate the corrosion area. The corrosion depth of electrolytic copper foil during corrosion testing can be obtained by X-ray micro-tomography (X-ray CT). For example, during the immersion corrosion process, an X-ray CT scanner is used to scan and obtain a three-dimensional image of the sample at regular intervals to analyze the corrosion depth of the copper foil surface. The corrosion depth refers to the average depth of all corroded areas. The corrosion start time can be determined by obtaining the corrosion area of the electrolytic copper foil each time. For example, when performing surface image analysis on the electrolytic copper foil, if a corrosion area appears on the surface of the electrolytic copper foil, the time when the electrolytic copper foil is taken out is the corrosion start time. Step 2: Generate a corrosion rate score based on the test data of the electrolytic copper foil in the corrosion test; Step 3: Obtaining corrosion status data of the electrolytic copper foil during the corrosion stagnation stage; wherein the corrosion status data includes the stagnation corrosion area and the stagnation corrosion depth; Step 4: Generate a corrosion degree score based on the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnation time point; Step 5: Classify the corrosion resistance of the electrolytic copper foil according to the corrosion rate score and the corrosion degree score; the classification types include primary corrosion resistance, secondary corrosion resistance and tertiary corrosion resistance.

[0027] As a preferred embodiment of the present invention, the corrosion stagnation time is obtained in the following manner: The corrosion area and corrosion depth of the electrolytic copper foil obtained each time are screened; wherein the screening method is specifically: removing the corrosion area and corrosion depth of the electrolytic copper foil before the corrosion start time, that is, removing the corrosion area and corrosion depth data of the electrolytic copper foil that do not exist; The corrosion area and corrosion depth of the electrolytic copper foil obtained each time are arranged in time sequence to generate a corrosion area dataset and a corrosion depth dataset; The corrosion area dataset and the corrosion depth dataset are respectively converted into corrosion area variation curves and corrosion depth variation curves in chronological order. For example, a two-dimensional coordinate system is established with time as the X-axis and the value in the corrosion area dataset as the Y-axis. The data in the corrosion area dataset is substituted into the two-dimensional coordinate system to generate the corrosion area variation curve. Similarly, the corrosion depth variation curve is obtained in the same way as the corrosion area variation curve. Substitute the corrosion area change curve and the corrosion depth change curve into the same two-dimensional coordinate system, and obtain a line segment in the corrosion area change curve and the corrosion depth change curve that is nearly parallel to the X-axis of the coordinate system (the starting point of the line segment is the same X-axis coordinate value on the X-axis). The starting point of the line segment is the corrosion stagnation time; It should be noted that the Y-axis of the same two-dimensional coordinate system is dimensionless so that the corrosion area change curve and the corrosion depth change curve can exist in the same two-dimensional coordinate system; for example, the Y-axis coordinate value of the corrosion depth change curve is denormalized and the value is reduced by m times, so that the distance between the corrosion area change curve and the corrosion depth change curve is reduced to facilitate subsequent identification.

[0028] See also Figure 2 As a preferred embodiment of the present invention, the corrosion rate score is generated in the following manner: S2.1: Generate corrosion start duration based on the corrosion start time; wherein the corrosion start duration refers to the time from the start of the corrosion test to the corrosion start time; S2.2: Generate a corrosion onset speed score based on the corrosion onset time; the corrosion onset speed score refers to the ratio of the corrosion onset time to the standard corrosion onset time; It should be noted that the standard corrosion onset time refers to the time from the start of the corrosion test to the corrosion onset time of the standard electrolytic copper foil during the corrosion test; in addition, the corrosion conditions (corrosive medium) of the standard electrolytic copper foil during the corrosion test are the same as the corrosion conditions of the current electrolytic copper foil; In this embodiment, compared with the corrosion start time of the standard electrolytic copper foil, the longer the corrosion start time of the electrolytic copper foil, the stronger the corrosion resistance of the copper foil surface may be. Because corrosion takes a certain amount of time to occur, this may be due to the formation of a relatively stable protective film (such as an oxide film or a passivation film) on the surface, which can effectively delay the onset of the corrosion reaction. If the corrosion start time is shorter, it means that the copper foil surface lacks an effective protective film, or its structure is easily eroded by the corrosive medium, thus initiating the corrosion process more quickly. In this case, the corrosion resistance of the copper foil is poor. S2.3: Generate the passivation film formation time according to the corrosion stagnation time; the passivation film formation time refers to the time from the start of corrosion to the corrosion stagnation time; S2.4: Generate a passivation film forming speed score based on the passivation film forming time; wherein the passivation film forming speed score refers to the ratio of the passivation film forming time to the standard passivation film forming time; In this embodiment, when the copper surface reacts with oxygen or other corrosive media during the corrosion process, a thin and dense layer of copper oxide (CuO) or other oxide is formed. This oxide film (i.e., passivation film) can effectively isolate the corrosive media (such as acid, oxygen, etc.) from direct contact with the copper metal, thereby slowing down or even stopping further corrosion. The formation of the passivation film makes the copper foil surface less active, greatly reducing the corrosion reaction rate, and even stopping it in some cases. In addition, compared with the passivation film forming time of the standard electrolytic copper foil, the longer the passivation film forming time of the electrolytic copper foil, the slower the reaction rate of the copper foil surface with oxygen or other corrosive media during the corrosion process, and the longer the time required for the passivation film to form, that is, the longer the corrosion stagnation time; the formation of the passivation film is formed by the reaction between the copper foil and the corrosive medium. The faster it forms, the shorter the time corresponding to the corrosion stagnation time, that is, the "passivation film forming time" is almost equivalent to the "corrosion stagnation time"; if the corrosion process quickly enters the stagnation stage, this may indicate that the corrosion reaction is strongly affected by the environment or medium, or The protective oxide layer on the surface of the copper foil is unstable and cannot effectively maintain its protective effect; therefore, the corrosion resistance of the copper foil is poor. For example, the corrosion stagnation time of a certain electrolytic copper foil is 40 hours, indicating that the surface of the copper foil can resist corrosion for a long time and can still maintain corrosion resistance for a long time after corrosion occurs. This may indicate that an effective protective film or passivation layer has been formed on its surface. However, the corrosion stagnation time of another electrolytic copper foil is 10 hours, indicating that the corrosion resistance of the copper foil is poor. There may be no effective passivation film on the surface, or the corrosion products have failed to form a sufficient protective layer to prevent further corrosion.

[0029] S2.5: Generate a corrosion rate score based on the initial corrosion rate score and the passive film formation rate score; wherein the corrosion rate score is the sum of the initial corrosion rate score and the passive film formation rate score; For example, by the formula: ; Generate corrosion rate score K t ; In the formula, C start It represents the initial corrosion rate score, C stagnate It represents the passivation film forming speed score, α and β are weight coefficients, and α+β=1; It should be noted that α and β are preset values, which are set by relevant personnel in this field. The methods for obtaining the values include but are not limited to expert consultation method, experimental calibration method, etc. In this embodiment, ideal corrosion resistance is generally manifested as a longer time required for corrosion to start and a longer corrosion stagnation time; this means that the copper foil can not only resist the initiation of the corrosion reaction for a longer period of time, but also maintain corrosion resistance for a longer period of time after the corrosion starts, and ultimately effectively slow down the continued corrosion through the formation of a passivation or protective layer.

[0030] See also Figure 3 As a preferred embodiment of the present invention, the method for generating the corrosion degree score specifically includes: S4.1: Generate a surface corrosion rate based on the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation time point; wherein the surface corrosion rate refers to the ratio of the stagnant corrosion area of the electrolytic copper foil during the corrosion stagnation stage to the surface area of the electrolytic copper foil; It should be noted that the stagnant corrosion area of the electrolytic copper foil during the corrosion stagnation stage refers to the total corrosion area on the surface of the electrolytic copper foil during the corrosion stagnation stage. S4.2: Generate a deep corrosion rate based on the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage; wherein the deep corrosion rate refers to the ratio of the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage to the thickness of the electrolytic copper foil; It should be noted that the stagnation corrosion depth of the electrolytic copper foil during the corrosion stagnation stage refers to the average corrosion depth of the electrolytic copper foil during the corrosion stagnation stage. S4.3: Generate a corrosion severity score based on the surface corrosion rate and the deep corrosion rate; Specifically, through the formula: ; Generate corrosion severity score K s ; In the formula, C a "It represents the surface corrosion rate threshold, C d " It represents the deep corrosion rate threshold, C a It represents the surface corrosion rate, C d It represents the deep corrosion rate, a1 and a2 are weight coefficients, and a1+a2=1; It should be noted that the values of a1 and a2 are set by relevant personnel in this field; In this embodiment, the surface corrosion area of the electrolytic copper foil is small during the corrosion stagnation stage, which generally indicates that the electrolytic copper foil has strong corrosion resistance. A protective film (such as a copper oxide film) can be formed on the surface of the electrolytic copper foil, thereby slowing down the corrosion process and protecting the internal metal from further corrosion. This phenomenon indicates that the electrolytic copper foil has good resistance to corrosive media. In other words, the smaller the surface corrosion rate of the electrolytic copper foil, the stronger the resistance of the electrolytic copper foil to corrosive media. If the corrosion depth is shallow, it usually means that the electrolytic copper foil has better corrosion resistance; the corrosion rate slows down, and the corrosion does not go deeper during the stagnation stage, which shows the effectiveness of the material surface protection mechanism; this phenomenon indicates that the electrolytic copper foil may have formed a dense and stable protective film, which reduces further corrosion. That is, the smaller the deep corrosion rate of the electrolytic copper foil, the stronger the resistance of the electrolytic copper foil to corrosive media. When corrosion stagnates, electrolytic copper foil with better corrosion resistance can form a stable passivation layer earlier and inhibit the corrosion process, thus showing a smaller corrosion area and shallower corrosion depth; conversely, electrolytic copper foil with poor corrosion resistance may continue to corrode until the material structure undergoes significant changes.

[0031] In addition, when electrolytic copper foil is used in lithium-ion batteries, its main function is to serve as the battery's current collector and effectively conduct electricity. If the surface corrosion area is too large, the copper foil's conductivity will decrease, affecting the battery's overall performance, especially during the charge and discharge process. Corrosion can lead to the interruption of the current path and a decrease in battery efficiency. That is, in lithium-ion batteries, the smaller the corrosion area when corrosion stagnates, the better, because a smaller corrosion area helps maintain the copper foil's conductivity, stability, and safety, thereby ensuring the battery's long-term stable operation and high-efficiency performance. At the same time, if the corrosion depth of the copper foil is large, it will cause structural damage to the copper foil and reduce its electrical conductivity, thereby affecting the charge and discharge performance of the battery; a shallower corrosion depth can maximize the conductivity of the copper foil and ensure efficient operation of the battery; the greater the corrosion depth of the copper foil, the greater the risk of surface damage and accumulation of corrosion products; these corrosion products may affect the capacity retention and cycle performance of the battery, especially the stability of the electrode material; therefore, a smaller corrosion depth helps the battery maintain a higher capacity and a longer cycle life during repeated charge and discharge.

[0032] See also Figure 4 As a preferred embodiment of the present invention, the method of classifying the corrosion resistance of the electrolytic copper foil includes: S5.1: Generate a corrosion resistance score based on the corrosion rate score and the corrosion severity score; wherein the corrosion resistance score is the difference between the corrosion rate score and the corrosion severity score; S5.2: Classify the corrosion resistance of electrolytic copper foil based on the corrosion resistance score; Specifically, the corrosion resistance score is compared with a preset score range; wherein the preset score range includes a first threshold and a second threshold, and the first threshold is less than the second threshold; If the corrosion resistance score is less than or equal to the first threshold, it means that the smaller the corrosion resistance score, the more abnormal the corrosion test result of the electrolytic copper foil, that is, the weaker the corrosion resistance of the electrolytic copper foil, and the corrosion resistance of the electrolytic copper foil is determined to be level three corrosion resistance; If the corrosion resistance score is greater than the first threshold and less than the second threshold, it means that the larger the corrosion resistance score, the more normal the corrosion test result of the electrolytic copper foil, that is, the more normal the corrosion resistance of the electrolytic copper foil, and the corrosion resistance of the electrolytic copper foil is determined to be level 2 corrosion resistance; If the corrosion resistance score is greater than the second threshold, it means that the larger the corrosion resistance score, the better the corrosion test result of the electrolytic copper foil, that is, the stronger the corrosion resistance of the electrolytic copper foil, and the corrosion resistance of the electrolytic copper foil is determined to be first-level corrosion resistance.

[0033] The present invention also provides a device for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries, which is used to perform the above-mentioned method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries, specifically comprising: Test assembly for performing corrosion tests on electrolytic copper foil; It should be noted that the test assembly is a corrosion resistance test assembly in the prior art, which can provide necessary support for corrosion testing of electrolytic copper foil; for example, when using an immersion corrosion test, the test assembly includes an immersion container, an immersion solution storage tank, a temperature control component, and a stirring component; See also Figure 5 , the device further comprises: The test data acquisition component 10 is used to obtain test data of the electrolytic copper foil in the corrosion test; wherein the test data includes corrosion area, corrosion depth, corrosion start time and corrosion stagnation time; A test data analysis unit 20 is used to generate a corrosion rate score based on the test data of the electrolytic copper foil in the corrosion test; The state data acquisition unit 30 is used to acquire the corrosion state data of the electrolytic copper foil during the corrosion stagnation stage; wherein the corrosion state data includes the stagnation corrosion area and the stagnation corrosion depth; A state analysis unit 40 is used to generate a corrosion degree score according to the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnation time point; The comprehensive analysis unit 50 is used to classify the corrosion resistance of the electrolytic copper foil according to the corrosion rate score and the corrosion degree score; wherein the classification types include primary corrosion resistance, secondary corrosion resistance and tertiary corrosion resistance.

[0034] See also Figure 6 , the test data analysis unit specifically includes: The corrosion start duration generating module 21 is used to generate the corrosion start duration according to the corrosion start time; wherein the corrosion start duration refers to the time from the start of the corrosion test to the corrosion start time; The corrosion start time analysis module 22 is used to generate a corrosion start speed score based on the corrosion start time; wherein the corrosion start speed score refers to the ratio between the corrosion start time and the standard corrosion start time; The passivation film forming time generating module 23 is used to generate the passivation film forming time according to the corrosion stagnation time; wherein the passivation film forming time refers to the time from the corrosion start time to the corrosion stagnation time; The passivation film forming speed analysis module 24 is used to generate a passivation film forming speed score according to the passivation film forming time; wherein the passivation film forming speed score refers to the ratio between the passivation film forming time and the standard passivation film forming time; The corrosion rate score generating module 25 is used to generate a corrosion rate score according to the initial corrosion rate score and the passivation film forming rate score; wherein the corrosion rate score refers to the sum of the initial corrosion rate score and the passivation film forming rate score.

[0035] See also Figure 7 , the state analysis unit specifically includes: The surface corrosion rate analysis module 41 is used to generate a surface corrosion rate based on the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation time point; wherein the surface corrosion rate refers to the ratio between the stagnant corrosion area of the electrolytic copper foil during the corrosion stagnation stage and the surface area of the electrolytic copper foil; The deep corrosion rate analysis module 42 is used to generate a deep corrosion rate according to the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage; wherein the deep corrosion rate refers to the ratio between the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage and the thickness of the electrolytic copper foil; The corrosion degree score generating module 43 is used to generate a corrosion degree score according to the surface corrosion rate and the deep corrosion rate.

[0036] See also Figure 8 , the comprehensive analysis unit specifically includes: A comprehensive analysis module 51 is used to generate a corrosion resistance score based on the corrosion rate score and the corrosion severity score; wherein the corrosion resistance score refers to the difference between the corrosion rate score and the corrosion severity score; The evaluation module 52 is used to classify the corrosion resistance of the electrolytic copper foil according to the corrosion resistance score.

[0037] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing the corrosion resistance of electrolytic copper foil for lithium-ion batteries, characterized in that: The following steps are involved: Conducting a corrosion test on the electrolytic copper foil to obtain test data of the electrolytic copper foil in the corrosion test; wherein the test data includes corrosion area, corrosion depth, corrosion start time, and corrosion stagnation time; Generate a corrosion rate score based on the test data of the electrolytic copper foil in the corrosion test; Obtaining corrosion status data of the electrolytic copper foil during the corrosion stagnation stage; wherein the corrosion status data includes the stagnation corrosion area and the stagnation corrosion depth; Generate a corrosion degree score based on the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnation time point; The corrosion resistance of electrolytic copper foil is classified according to the corrosion rate score and corrosion degree score.

2. The method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries according to claim 1, wherein: The corrosion stagnation time is obtained in the following manner: The corrosion area and corrosion depth of the electrolytic copper foil obtained each time are screened; wherein the screening method is specifically: removing the corrosion area and corrosion depth of the electrolytic copper foil before the corrosion start time; The corrosion area and corrosion depth of the electrolytic copper foil obtained each time are arranged in time sequence to generate a corrosion area dataset and a corrosion depth dataset; The corrosion area dataset and the corrosion depth dataset are respectively used to generate the corrosion area change curve and the corrosion depth change curve in time sequence; Substitute the corrosion area change curve and the corrosion depth change curve into the same two-dimensional coordinate system to obtain a line segment in the corrosion area change curve and the corrosion depth change curve that is nearly parallel to the X-axis of the coordinate system. The starting point of the line segment is the corrosion stagnation time.

3. The method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries according to claim 1, wherein: The corrosion rate score is generated in the following manner: Generate the corrosion start duration according to the corrosion start time; the corrosion start duration refers to the time from the start of the corrosion test to the corrosion start time; Generate a corrosion start speed score based on the corrosion start time; the corrosion start speed score refers to the ratio of the corrosion start time to the standard corrosion start time; Generate the passivation film formation time according to the corrosion stagnation time; the passivation film formation time refers to the time from the start of corrosion to the corrosion stagnation time; Generate a passivation film forming speed score based on the passivation film forming time; wherein the passivation film forming speed score refers to the ratio between the passivation film forming time and the standard passivation film forming time; A corrosion rate score is generated based on the corrosion start rate score and the passive film formation rate score; wherein the corrosion rate score refers to the sum of the corrosion start rate score and the passive film formation rate score.

4. The method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries according to claim 1, wherein: The method for generating the corrosion degree score specifically includes: The surface corrosion rate is generated based on the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation time point; wherein the surface corrosion rate refers to the ratio between the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation stage and the surface area of the electrolytic copper foil; According to the stagnation corrosion depth of the electrolytic copper foil in the corrosion stagnation stage, a deep corrosion rate is generated; wherein the deep corrosion rate refers to the ratio between the stagnation corrosion depth of the electrolytic copper foil in the corrosion stagnation stage and the thickness of the electrolytic copper foil; A corrosion severity score is generated based on the surface corrosion rate and deep corrosion rate.

5. The method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries according to claim 4, wherein: The corrosion degree score is generated based on the surface corrosion rate and the deep corrosion rate, specifically: By formula: ； Generate corrosion severity score K s ; In the formula, C a " It represents the surface corrosion rate threshold, C d " It represents the deep corrosion rate threshold, C a It represents the surface corrosion rate, C d It represents the deep corrosion rate, a1 and a2 are weight coefficients, and a1+a2=1.

6. The method for testing the corrosion resistance of electrolytic copper foil for lithium ion batteries according to claim 1, wherein: The methods for classifying the corrosion resistance of electrolytic copper foil include: Generate a corrosion resistance score based on the corrosion rate score and the corrosion severity score; the corrosion resistance score refers to the difference between the corrosion rate score and the corrosion severity score; The corrosion resistance of electrolytic copper foil is classified according to the corrosion resistance score.

7. A corrosion resistance testing device for electrolytic copper foil for lithium ion batteries, characterized in that: The device is used to perform a corrosion resistance testing method for electrolytic copper foil for lithium ion batteries according to any one of claims 1 to 6, specifically comprising: Test assembly for performing corrosion tests on electrolytic copper foil; A test data acquisition component is used to obtain test data of the electrolytic copper foil in the corrosion test; wherein the test data includes corrosion area, corrosion depth, corrosion start time and corrosion stagnation time; A test data analysis unit, used to generate a corrosion rate score based on the test data of the electrolytic copper foil in the corrosion test; A state data acquisition unit is used to acquire corrosion state data of the electrolytic copper foil during the corrosion stagnation stage; wherein the corrosion state data includes the stagnation corrosion area and the stagnation corrosion depth; A state analysis unit is used to generate a corrosion degree score based on the stagnant corrosion area and stagnant corrosion depth of the electrolytic copper foil at the corrosion stagnation time point; The comprehensive analysis unit is used to classify the corrosion resistance of the electrolytic copper foil according to the corrosion rate score and the corrosion degree score; wherein the classification types include primary corrosion resistance, secondary corrosion resistance and tertiary corrosion resistance.

8. The corrosion resistance testing device for electrolytic copper foil for lithium ion batteries according to claim 7, characterized in that: The test data analysis unit specifically includes: The corrosion start duration generation module is used to generate the corrosion start duration according to the corrosion start time; wherein the corrosion start duration refers to the time from the start of the corrosion test to the corrosion start time; The corrosion onset time analysis module is used to generate a corrosion onset speed score based on the corrosion onset time. The corrosion onset speed score refers to the ratio of the corrosion onset time to the standard corrosion onset time. The passivation film formation time generation module is used to generate the passivation film formation time according to the corrosion stagnation time; wherein the passivation film formation time refers to the time from the start time of corrosion to the corrosion stagnation time; A passivation film forming speed analysis module is used to generate a passivation film forming speed score based on the passivation film forming time; wherein the passivation film forming speed score refers to the ratio between the passivation film forming time and the standard passivation film forming time; The corrosion rate score generating module is used to generate a corrosion rate score according to the starting corrosion rate score and the passivation film forming rate score; wherein the corrosion rate score refers to the sum of the starting corrosion rate score and the passivation film forming rate score.

9. The corrosion resistance testing device for electrolytic copper foil for lithium ion batteries according to claim 7, characterized in that: The state analysis unit specifically includes: The surface corrosion rate analysis module is used to generate a surface corrosion rate based on the stagnant corrosion area of the electrolytic copper foil at the corrosion stagnation time point; the surface corrosion rate refers to the ratio between the stagnant corrosion area of the electrolytic copper foil during the corrosion stagnation stage and the surface area of the electrolytic copper foil; A deep corrosion rate analysis module is used to generate a deep corrosion rate based on the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage; wherein the deep corrosion rate refers to the ratio between the stagnant corrosion depth of the electrolytic copper foil during the corrosion stagnation stage and the thickness of the electrolytic copper foil; The corrosion degree score generating module is used to generate a corrosion degree score according to the surface corrosion rate and the deep corrosion rate.

10. The corrosion resistance testing device for electrolytic copper foil for lithium ion batteries according to claim 7, characterized in that: The comprehensive analysis unit specifically includes: A comprehensive analysis module is used to generate a corrosion resistance score based on the corrosion rate score and the corrosion severity score; wherein the corrosion resistance score is the difference between the corrosion rate score and the corrosion severity score; The evaluation module is used to classify the corrosion resistance of the electrolytic copper foil according to the corrosion resistance score.

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