Method for testing wear rate of negative pole piece of battery

Abstract

The invention relates to the technical field of batteries, in particular to a method for testing the wear rate of a negative pole piece of a battery. The method for testing the wear rate of the negative pole piece of the battery comprises the following steps: cutting the negative pole piece, weighing the cut negative pole piece, and recording the weight as M1; folding the paper and fixing four corners of the paper; inserting a part of the negative pole piece into a gap of the folded paper, and pressing the negative pole piece on the paper by using a pressing wheel; connecting a weight with the negative pole piece, enabling the weight to freely fall, enabling the negative pole piece to rub with the paper to fall powder, and stopping the weight after the weight falls by a preset distance; taking out the negative pole piece, weighing the negative pole piece, and recording the weight as M2; and calculating the powder falling rate of the negative pole piece, wherein the powder falling rate of the negative pole piece is equal to (M1-M2) / M1 * 100%. By measuring the powder falling rate of the negative pole piece, the negative pole piece with the unqualified powder falling rate is prevented from being conveyed to the rolling process, the frequency of wiping the roller surface by an operator is reduced, the working efficiency is improved, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a method for testing the wear rate of a negative electrode plate of a battery. Background Art

[0002] The rolling process is one of the important processes in the battery manufacturing process, and it has an important impact on the battery rate discharge and cycle. In order to improve the product yield of the battery, reduce or eliminate the problem of powder loss of the battery negative electrode, and thus improve the risk of short circuit or diaphragm tearing in the battery cell, although the industry is currently equipped with a scraper mechanism and an automatic roller wiping mechanism to clean the roller surface, in certain specific cases, operators are still required to wipe the roller surface frequently to ensure the cleanliness of the roller surface during the rolling process and avoid or reduce the adhesion of graphite powder on the roller surface. Operators repeatedly wipe the roller surface, which not only increases labor costs, but also reduces work efficiency and affects production rhythm.

[0003] Therefore, it is urgent to design a test method for the wear rate of the negative electrode plate of the battery to solve the above technical problems. Summary of the invention

[0004] The purpose of the present invention is to propose a test method for the wear rate of a negative electrode sheet of a battery. By measuring and monitoring the powder loss rate of the negative electrode sheet upstream of the rolling process, it is possible to prevent negative electrode sheets with unqualified powder loss rates from being transmitted to the rolling process, reduce the frequency of operators wiping the roller surface, improve work efficiency, and save costs.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for testing the wear rate of a negative electrode plate of a battery, comprising:

[0007] Cut the negative electrode sheet and weigh the cut negative electrode sheet, and record the weight as M1;

[0008] Fold the paper in half and fix the four corners of the folded paper on the work platform;

[0009] Insert part of the negative electrode into the gap of the folded paper, and press the paper with a pressure wheel to ensure that the pressure wheel presses the negative electrode through the paper;

[0010] Connect the weight to the negative electrode and let it fall freely, so that the negative electrode rubs against the paper and the powder falls off. Stop the weight after it falls a preset distance.

[0011] Take out the negative electrode sheet and weigh it, and record the weight as M2;

[0012] Calculate the powder loss rate of the negative electrode sheet: the powder loss rate of the negative electrode sheet = (M1-M2) / M1×100%.

[0013] As an optional technical solution for testing the wear rate of a negative electrode sheet of a battery, the steps of cutting the negative electrode sheet, weighing the cut negative electrode sheet, and recording the weight as M1 include:

[0014] Cut the negative electrode sheet into strips of 300mm×40mm.

[0015] As an optional technical solution for testing the wear rate of a negative electrode of a battery, the step of folding the paper in half and fixing the four corners of the folded paper on the working platform also includes:

[0016] Fold the A4 paper in half and use transparent tape to fix the four corners of the folded A4 paper on the work platform.

[0017] As an optional technical solution for testing the wear rate of a negative electrode plate of a battery, the step of inserting a portion of the negative electrode plate into the gap of the folded paper includes:

[0018] The length of the negative electrode sheet inserted into the paper gap is 200mm±5mm.

[0019] As an optional technical solution for a method of testing the wear rate of a negative electrode plate of a battery, the area where the pressing wheel presses on the paper is not less than the area of ​​the negative electrode plate.

[0020] As an optional technical solution for testing the wear rate of a negative electrode plate of a battery, the steps of connecting a weight to the negative electrode plate and letting the weight fall freely so that the negative electrode plate rubs against paper to remove powder, and stopping the movement after the weight falls a preset distance include:

[0021] The weight is connected to the end of the negative electrode sheet exposed from the paper through a connecting rope, and a support plate is set at a preset distance. The weight stops moving after freely falling to the support plate.

[0022] As an optional technical solution for a test method for the wear rate of a battery negative electrode plate, the preset distance is set to 150mm±20mm.

[0023] As an optional technical solution for testing the wear rate of a negative electrode of a battery, the weight of the weight is set to 200g±0.1g.

[0024] As an optional technical solution for testing the wear rate of a negative electrode plate of a battery, the step of removing the negative electrode plate includes:

[0025] Remove the connecting rope from the negative electrode, remove the pressure wheel, lift the paper to take out the negative electrode, and brush off the powder on the negative electrode with a brush.

[0026] As an optional technical solution for testing the wear rate of a battery negative electrode sheet, an analytical balance is used to weigh the negative electrode sheet.

[0027] The beneficial effects of the invention include at least:

[0028] The invention provides a method for testing the wear rate of a negative electrode sheet of a battery. The method comprises the following steps: cutting a negative electrode sheet, weighing the cut negative electrode sheet, and recording the weight as M1; folding a paper in half, and fixing the four corners of the folded paper on a work platform; inserting a part of the negative electrode sheet into a gap of the folded paper, and pressing the paper with a pressing wheel to ensure that the pressing wheel presses the negative electrode sheet through the paper; connecting a weight to the negative electrode sheet, and letting the weight fall freely, so that the negative electrode sheet rubs against the paper and loses powder, and the weight stops moving after falling a preset distance; taking out the negative electrode sheet, and weighing the negative electrode sheet, and recording the weight as M2; and calculating the powder loss rate (wear rate) of the negative electrode sheet, wherein the powder loss rate of the negative electrode sheet=(M1-M2) / M1×100%.

[0029] As described above, the test method for the wear rate of the negative electrode sheet of the battery is applied to the upstream of the roller pressing process. The weight drives the negative electrode sheet to move so that the negative electrode sheet and the paper produce friction and powder loss. The weight of the negative electrode sheet before and after the test is weighed to calculate the powder loss rate of the negative electrode sheet. The powder loss rate of the negative electrode sheet is tested by using the test method for the wear rate of the negative electrode sheet of the battery. The operator can adjust the parameters of the coating oven in the negative electrode sheet coating process according to the powder loss rate to ensure that the powder loss rate is qualified. Reduce or avoid the transmission of negative electrode sheets with unqualified powder loss rates to the downstream process (i.e., the roller pressing process), thereby reducing the frequency of operators wiping the roller surface, improving work efficiency, and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0031] Figure 1 It is a flow chart of a method for testing the wear rate of a negative electrode plate of a battery provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] The present embodiment provides a method for testing the wear rate of a negative electrode plate of a battery. By measuring and monitoring the powder loss rate (wear rate) of the negative electrode plates upstream of the rolling process, negative electrode plates with unqualified powder loss rates are prevented from being transferred to the rolling process, thereby reducing the frequency of operators wiping the roller surface, improving work efficiency, and saving costs.

[0040] like Figure 1 As shown, the test method for the wear rate of the negative electrode plate of the battery mainly includes:

[0041] The negative electrode sheet is cut and weighed, and the weight is recorded as M1; the paper is folded in half, and the four corners of the folded paper are fixed on the working platform; part of the negative electrode sheet is inserted into the gap of the folded paper, and a pressure wheel is pressed on the paper to ensure that the pressure wheel presses the negative electrode sheet through the paper; the weight is connected to the negative electrode sheet, and the weight is freely dropped to make the negative electrode sheet rub against the paper to drop powder, and the weight stops moving after falling a preset distance; the negative electrode sheet is taken out and weighed, and the weight is recorded as M2; the powder loss rate of the negative electrode sheet is calculated.

[0042] The powder loss rate of the negative electrode sheet = (M1-M2) / M1×100%.

[0043] Based on the above design, in this embodiment, the test method for the wear rate of the negative electrode plate of the battery is applied to the upstream of the roller pressing process. The weight drives the negative electrode plate to move so that the negative electrode plate and the paper produce friction and powder loss. The weight of the negative electrode plate before and after the test is weighed to calculate the powder loss rate of the negative electrode plate. By using the test method for the wear rate of the negative electrode plate of the battery to test the powder loss rate of the negative electrode plate, the operator can adjust the parameters of the coating oven in the negative electrode plate coating process according to the powder loss rate to ensure that the powder loss rate is qualified. Reduce or avoid the transmission of negative electrode plates with unqualified powder loss rates to the downstream process (i.e., the roller pressing process), thereby reducing the frequency of operators wiping the roller surface, improving work efficiency, and saving costs.

[0044] In addition, the test method for the wear rate of the battery negative electrode plate is simple and convenient to operate, and the results are easy to obtain. There is no need to immerse the negative electrode plate in a solution to obtain the powder loss rate, etc., thereby improving work efficiency and saving costs.

[0045] It should be noted that the two opposite sides of the negative electrode plate in this embodiment are coated with graphite powder.

[0046] The specific steps of the test method for the wear rate of the negative electrode plate of the battery are described in detail below:

[0047] The negative electrode sheet is cut, and the cut negative electrode sheet is weighed, and the weight is recorded as M1. By cutting the negative electrode sheet, subsequent measurement tests are facilitated and the waste of large-area negative electrode sheets is reduced. Optionally, in this embodiment, an analytical balance is used to weigh the cut negative electrode sheet, and the weight is recorded as M1.

[0048] Specifically, the negative electrode sheet is cut into strips of 300mm×40mm, which makes it easier for the subsequent pressing wheel to press the negative electrode sheet, improves the consistency of the friction between the negative electrode sheet and the paper, and thus improves the stability of the powder loss rate test data and reduces test errors.

[0049] Fold the paper in half, and fix the four corners of the folded paper on a work platform. Optionally, the work platform can be a tabletop in a laboratory.

[0050] Specifically, fold the A4 paper in half once, and use transparent tape to fix the four corners of the folded A4 paper on the work platform. The paper in this embodiment can be A4 paper commonly found on the market, which is easy to obtain and low in cost. In this embodiment, the A4 paper is folded in half once, so that the flatness of the A4 paper can be ensured as much as possible, reducing the test error. Transparent tape is not only low in cost and easy to obtain; it also facilitates the subsequent disassembly of the A4 paper and improves work efficiency. Use transparent tape to fix the four corners of the folded A4 paper on the work platform to improve the stability and reliability of the A4 paper, and ensure that the negative electrode plate will rub against the A4 paper and lose powder when the negative electrode plate moves with the weight.

[0051] Insert part of the negative electrode sheet into the gap of the folded paper, and press the paper with a pressure wheel to ensure that the pressure wheel presses the negative electrode sheet through the paper. In other words, a part of the negative electrode sheet is inserted into the gap of the paper, and the pressure wheel applies pressure to part of the electrode sheet, thereby ensuring that the negative electrode sheet and the paper fit tightly, which is conducive to the subsequent friction between the negative electrode sheet and the A4 paper when the weight moves.

[0052] In this embodiment, the long side of the strip-shaped negative electrode sheet is inserted into the gap parallel to the long side of the folded A4 paper.

[0053] Furthermore, the length of the negative electrode sheet inserted into the paper gap in this embodiment is 200mm±5mm. This can improve the accuracy of the test as much as possible. When the length of the negative electrode sheet inserted into the paper gap is less than 195mm, the contact area between the negative electrode sheet and the paper is too small, which affects the accuracy of the powder loss rate test; when the length of the negative electrode sheet inserted into the paper gap is greater than 205mm, the part of the negative electrode sheet exposed from the paper is too short, which is not convenient for the subsequent connection of the weight and the negative electrode sheet, reducing the stability of the test data.

[0054] Furthermore, the area of ​​the pressing wheel pressing on the paper is not less than the area of ​​the negative electrode sheet, so that the negative electrode sheet inserted into the gap of the paper can be pressed by the pressing wheel, so that each area of ​​the negative electrode sheet inserted into the gap of the paper is in close contact with the paper, thereby improving the stability of the test data.

[0055] Connect the weight to the negative electrode and let it fall freely, so that the negative electrode rubs against the paper and produces powder. Stop the weight after it falls a preset distance. The weight can drive the negative electrode to move through the free fall of the weight, so that the negative electrode rubs against the paper and produces powder.

[0056] Optionally, the preset distance in this embodiment can be set to 150mm±20mm, and the distance of the weight movement is set to 130mm-170mm, so as to ensure the stability and accuracy of the test data. When the weight movement distance is less than 130mm, the friction time between the negative electrode plate and the paper is short, and the powder loss is not ideal. When the weight movement distance is greater than 170mm, the friction time between the negative electrode plate and the paper is long, and the paper will cause certain wear on the negative electrode plate itself, affecting the accuracy of the test data.

[0057] Furthermore, the weight is connected to the end of the negative electrode sheet exposed from the paper by a connecting rope, and a support plate is set at a preset distance, and the weight stops moving after freely falling to the support plate. One end of the connecting rope is connected to the negative electrode sheet, and the other end is connected to the weight. The setting of the connecting rope can improve the stability and convenience of the connection between the weight and the negative electrode sheet, and improve work efficiency. The setting of the support plate can make the weight stop immediately after moving to the preset distance, thereby improving the reliability of the test data.

[0058] For example, one end of the connecting rope can be connected to the end of the negative electrode sheet exposed from the paper through a clamp, and the other end of the connecting rope is wound around the weight, thereby improving the convenience and work efficiency of connecting the connecting rope to the negative electrode sheet.

[0059] Optionally, the weight of the weight in this embodiment is set to 200g±0.1g. Ensure the stability of the movement of the negative electrode sheet driven by the weight. When the weight of the weight is too heavy, the pressure wheel cannot press the negative electrode sheet tightly, which will cause the negative electrode sheet to slip out of the paper, resulting in test failure; when the weight of the weight is too light, it is difficult for the weight to drive the negative electrode sheet to move relative to the paper, which will result in insufficient friction between the negative electrode sheet and the paper, thereby affecting the powder loss of the negative electrode sheet.

[0060] Take out the negative electrode sheet and weigh it, and record the weight as M2.

[0061] Specifically, first remove the connecting rope from the negative electrode sheet, then remove the pressure wheel, and finally lift the folded paper to take out the negative electrode sheet, and use a brush to brush off the powder on the negative electrode sheet. Use an analytical balance to weigh the negative electrode sheet, and record the weight as M2.

[0062] Calculate the powder loss rate of the negative electrode sheet: the powder loss rate of the negative electrode sheet = (M1-M2) / M1×100%.

[0063] It can be understood that M1 is the initial weight of the negative electrode sheet, and M2 is the weight of the negative electrode sheet after the test. During the test, the negative electrode sheet and the paper will generate a certain friction, which will cause the negative electrode sheet to lose powder. M1-M2 is the weight of the powder (such as graphite powder) that falls off due to friction of the negative electrode sheet during the test, and finally the powder loss rate of the negative electrode sheet is obtained.

[0064] Normally, the powder loss rate (wear rate) of the negative electrode sheet is ≤0.1%, indicating that the negative electrode sheet is qualified. When the powder loss rate of the negative electrode sheet is greater than 0.1%, the operator needs to adjust the parameters of the coating oven in the coating process of the negative electrode sheet to ensure that the powder loss rate is qualified, thereby achieving the purpose of monitoring the powder loss rate of the negative electrode sheet, improving the production yield of the negative electrode sheet, reducing or avoiding the flow of defective products into the roller process, thereby reducing the frequency of operators wiping the roller surface, improving work efficiency, and saving costs.

[0065] Experimental example:

[0066] Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Weight before test (g) 2.2011 2.2035 2.2022 2.2033 2.2017 2.2016 Weight after test (g) 2.1996 2.2021 2.2007 2.2019 2.2001 2.2002 Powder loss rate / wear rate (%) 0.06815 0.06354 0.06811 0.06354 0.07267 0.06359

[0067] By comparing the test results of the six groups of samples in the above test examples, it can be concluded that the powder loss rates of the six groups of samples (negative electrode sheets) are all within 0.1%, so it can be judged that the above six groups of samples are qualified.

[0068] Obviously, the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

[0069] Note that in the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

Claims

1. A method for testing the wear rate of a negative electrode of a battery, characterized in that: include: Cut the negative electrode sheet and weigh the cut negative electrode sheet, and record the weight as M1; Fold the paper in half and fix the four corners of the folded paper on the work platform; Insert part of the negative electrode into the gap of the folded paper, and press the paper with a pressure wheel to ensure that the pressure wheel presses the negative electrode through the paper; Connect the weight to the negative electrode and let it fall freely, so that the negative electrode rubs against the paper and the powder falls off. Stop the weight after it falls a preset distance. Take out the negative electrode sheet and weigh it, and record the weight as M2; Calculate the powder loss rate of the negative electrode sheet: the powder loss rate of the negative electrode sheet = (M1-M2) / M1×100%.

2. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 1, characterized in that: The steps of cutting the negative electrode sheet, weighing the cut negative electrode sheet, and recording the weight as M1 include: Cut the negative electrode sheet into strips of 300mm×40mm.

3. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 1, characterized in that: The step of folding the paper in half and fixing the four corners of the folded paper on the working platform also includes: Fold the A4 paper in half and use transparent tape to fix the four corners of the folded A4 paper on the work platform.

4. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 1, characterized in that: The step of inserting part of the negative electrode sheet into the gap of the folded paper includes: The length of the negative electrode sheet inserted into the paper gap is 200mm±5mm.

5. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 1, characterized in that: The area of ​​the pressing wheel pressing on the paper is not less than the area of ​​the negative electrode plate.

6. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 1, characterized in that: The steps of connecting the weight to the negative electrode plate, allowing the weight to fall freely, causing the negative electrode plate to rub against the paper to remove powder, and stopping the movement of the weight after it falls a preset distance include: The weight is connected to the end of the negative electrode sheet exposed from the paper through a connecting rope, and a support plate is set at a preset distance. The weight stops moving after freely falling to the support plate.

7. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 6, characterized in that: The preset distance is set to 150mm±20mm.

8. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 6, characterized in that: The weight of the weight is set to 200g±0.1g.

9. The method for testing the wear rate of the negative electrode sheet of a battery according to claim 6, characterized in that: The step of removing the negative electrode sheet comprises: Remove the connecting rope from the negative electrode, remove the pressure wheel, lift the paper to take out the negative electrode, and brush off the powder on the negative electrode with a brush.

10. The method for testing the wear rate of the negative electrode plate of a battery according to claim 1, characterized in that: The negative electrode was weighed using an analytical balance.

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