Method for improving tab alignment degree of winding battery

Abstract

The invention belongs to the technical field of battery manufacturing, and discloses a method for improving the tab alignment degree of a winding battery. The method provided by the invention comprises the following steps: when a roll changing instruction of the winding equipment is triggered, recording a first conveying length value L1 of an output raw material after a single-roll winding needle rotates by a preset angle phi; after the raw material roll is replaced and a single-roll winding needle rotates by a preset angle phi, a second conveying length value L2 of the output raw material after roll replacement is recorded; when the absolute value of the length difference value delta L of the first conveying length value L1 and the second conveying length value L2 exceeds a preset difference value delta L0, the tab is judged to have deviation; and adjusting the thickness of the pole piece according to the length difference delta L. By adopting the method provided by the invention, the tab dislocation information can be found in time in the roll changing process, the tab alignment degree is automatically adjusted according to the dislocation information, the adjustment precision is improved, and the rejection rate is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of battery manufacturing, and in particular to a method for winding a battery to improve the alignment of tabs. Background Art

[0002] During the winding process of wound batteries, the alignment of the pole lugs is greatly affected by the thickness of the incoming materials. The fluctuation of pole piece thickness is mainly manifested in the replacement of pole rolls and diaphragms (speed reduction in rolling incoming materials, changes in diaphragm batches, large tension in the inner ring of the diaphragm and thin inner ring extrusion pressure, etc.). The current industry approach is to adjust the Teflon on the winding needle or change the winding needle diameter according to the pole lug misalignment information of the first battery cell after changing the roll. It is often necessary to scrap at least one battery cell to confirm the misalignment, and various remedial measures are taken for the next battery cell. This strategy often has a lag problem. Once the pole piece thickness (diaphragm thickness) fluctuates greatly before and after the roll change, the pole lug alignment is poor and scrapping is often inevitable. The more roll changes are made, the more scrapping will be caused.

[0003] Therefore, it is urgent to propose a method that can timely detect the misalignment information of the tabs during the roll change process and automatically adjust the alignment of the tabs according to the misalignment information. Summary of the invention

[0004] The object of the present invention is to provide a method for improving the alignment of the tabs of a wound battery. The method provided by the present invention can timely detect the tab misalignment information during the winding process, and automatically adjust the tab alignment according to the misalignment information, thereby improving the adjustment accuracy and reducing the scrap rate.

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

[0006] The present invention discloses a method for improving the alignment of tabs of a wound battery, comprising the following steps:

[0007] When the roll change instruction of the winding device is triggered, the single roll winding needle rotates by a preset angle Φ and then records the first conveying length value L1 of the output raw material;

[0008] After the raw material roll is replaced, after the single roll winding needle rotates the preset angle Φ, the second conveying length value L2 of the raw material output after the roll is replaced is recorded;

[0009] When the absolute value of the length difference ΔL between the first conveying length value L1 and the second conveying length value L2 exceeds the preset difference ΔL0, it is determined that the tab has a deviation;

[0010] The thickness of the pole piece is adjusted according to the length difference ΔL.

[0011] A method for improving the alignment of the tabs of a wound battery of the present invention has the following beneficial effects: during the execution of a roll changing instruction, first measuring the rotation of a single roll winding needle by a preset angle Φ and then recording the first conveying length value L1 of the output raw material; after measuring the replacement of the raw material roll, after the single roll winding needle rotates by the preset angle Φ, recording the second conveying length value L2 of the output raw material after the roll changing; the length difference ΔL between the first conveying length value L1 and the second conveying length value L2 can clearly characterize the thickness difference of the output raw material before and after the roll changing; if the absolute value of the length difference ΔL exceeds the preset difference ΔL0, it can be determined that the tab will definitely be misaligned in the subsequent winding process; at this time, by adjusting the thickness of the pole piece according to the length difference ΔL, the offset of the tab can be corrected in time, thereby achieving the purpose of timely discovering the misalignment information of the tab during the roll changing process and automatically adjusting the alignment of the tab according to the misalignment information, thereby improving the error correction accuracy of the tab and reducing the scrap rate.

[0012] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the structure of the winding device;

[0014] Figure 2 It is a schematic flow chart of a method for improving the alignment of tabs of a wound battery according to the first embodiment of the present invention.

[0015] Reference numerals:

[0016] 100, battery cell winding needle; 200, positive electrode sheet; 300, negative electrode sheet; 400, upper separator; 500, lower separator; 600, single winding needle; 700, electrode sheet shaping roller; DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0018] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" 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; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In the description of this embodiment, the terms "upper", "lower", "left", "right", "front", "rear" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0020] The present invention discloses a method for improving the alignment of the tabs of a wound battery (hereinafter referred to as the method provided by the present invention for convenience of description), referring to Figure 2 As shown, the method provided by the present invention comprises the following steps:

[0021] S1: When the roll change instruction of the winding device is triggered, the single roll winding needle 600 rotates a preset angle Φ and then records the first conveying length value L1 of the output raw material;

[0022] S2: After the raw material roll is replaced, after the single roll winding needle 600 rotates the preset angle Φ, the second conveying length value L2 of the raw material output after the roll is replaced is recorded;

[0023] S3: When the absolute value of the length difference ΔL between the first conveying length value L1 and the second conveying length value L2 exceeds the preset difference ΔL0, it is determined that the tab has a deviation;

[0024] S4: Adjust the thickness of the pole piece according to the length difference ΔL.

[0025] It should be noted that the reference Figure 1 As shown, during the cell winding process, whether it is the electrode roll (including the positive electrode 200 and the negative electrode 300) or the diaphragm roll (including the upper diaphragm 400 and the lower diaphragm 500) that needs to be changed, there is a single-winding action to find the starting point of the EA or the position of the diaphragm adhesive tape. The single-winding process is that when the roll change instruction of the winding equipment is triggered, the single-winding needle 600 rotates to roll up the remaining part of the old raw material roll. After the roll change is completed, a part of the new raw material roll is rolled up, and then the cell winding needle 100 will continue to wind and manufacture the cell. If the thickness of the output raw material is always a fixed value, then before and after the roll change, the pole ears on the wound cell should be set directly opposite, and there will be no deviation. However, due to production and manufacturing reasons, there will be a thickness deviation between the new raw material roll and the old raw material roll. In this case, the pole ear misalignment phenomenon will occur before and after the roll change.

[0026] It can be understood that the method disclosed in this embodiment first measures the first conveying length value L1 of the output raw material after the single-roll winding needle 600 rotates the preset angle Φ during the execution of the roll changing instruction, and then records the second conveying length value L2 of the output raw material after the roll changing after the single-roll winding needle 600 rotates the preset angle Φ after measuring the replacement of the raw material roll. The length difference ΔL between the first conveying length value L1 and the second conveying length value L2 can clearly characterize the thickness difference of the output raw material before and after the roll changing. If the absolute value of the length difference ΔL exceeds the preset difference ΔL0, it can be determined that the pole ear will definitely be misaligned in the subsequent winding process. At this time, the thickness of the pole piece is adjusted according to the length difference ΔL, so that the offset of the pole ear can be corrected in time, thereby achieving the purpose of timely detecting the misalignment information of the pole ear during the roll changing process and automatically adjusting the alignment of the pole ear according to the misalignment information, thereby improving the error correction accuracy of the pole ear and reducing the scrap rate.

[0027] It should be supplemented that the first conveying length value L1 and the second conveying length value L2 can be measured by a length-counting roller provided on the conveying path of the output raw material in the winding device, or by providing a detector on the single-roll winding needle 600, and measuring the increase in the diameter of the material wound on the single-roll winding needle 600 and converting it into the first conveying length value L1 and the second conveying length value L2. Of course, in the implementation of the method provided by the present invention, the first conveying length value L1 and the second conveying length value L2 can also be measured according to actual needs, and are not limited to the above description.

[0028] Optionally, the range of the preset difference ΔL0 is: 1mm-5mm, and the preset difference ΔL0 can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm. Of course, the preset difference ΔL0 can also be selected from other values ​​within 1mm-5mm according to actual needs, and is not limited to the above examples. In the process of implementing the method provided by the present invention, the preset difference ΔL0 needs to be determined according to the actual requirements of the battery cell winding.

[0029] Optionally, the length difference ΔL and the thickness compensation value h of the pole piece satisfy the relationship: h = ((ΔL / (Φ / 360)) / 6.28)*Q. Q is a compensation constant, and the range is 0.01-5. The compensation constant is set according to practical experience and parameters such as the pole piece winding process requirements. In other embodiments of the present invention, the relationship between the length difference ΔL and the thickness compensation value h of the pole piece can be changed according to actual needs. The above formula only provides a method for calculating the thickness of the pole piece.

[0030] Optionally, the range of the preset angle Φ is: 1080°-5400°. Specifically, the preset angle Φ can be 1080°, 1440°, 1800°, 2160°, 2520°, 2880°, 3240°, 3600°, 3960°, 4320°, 4680°, 5040°, 5400°. Of course, the preset angle Φ can also be other values ​​within the above range, and is not limited to the above examples. It can be understood that if the value of the preset angle Φ is too large, it will prolong the time required for detecting the first conveying length value L1 and the second conveying length value L2 during the method provided by the present invention, thereby affecting the manufacturing efficiency of the battery cell. And because the larger the angle of the single-roll winding needle 600, the larger the length difference ΔL between the first conveying length value L1 and the second conveying length value L2 is measured, if the preset angle Φ is set too large, the probability of misjudgment may be increased. If the value of the preset angle Φ is too small, although the time required to detect the first conveying length value L1 and the second conveying length value L2 will be shortened, the difference ΔL between the first conveying length value L1 and the second conveying length value L2 will be smaller as the angle of the single-roll winding needle 600 turns, which will also increase the probability of misjudgment. In this embodiment, the preset angle Φ is set to: 1080°-5400°, which can control the time required to detect the first conveying length value L1 and the second conveying length value L2, ensure the manufacturing efficiency of the battery cell, and reduce the probability of misjudgment and improve the adjustment accuracy.

[0031] It should be noted that, in other embodiments of the present invention, the preset angle Φ can also be selected according to actual needs and is not limited to the above-mentioned limitation. In order to facilitate data recording, the preset angle Φ is preferably an integer multiple of 360°.

[0032] Optionally, the output raw material includes at least one of the positive electrode sheet 200, the negative electrode sheet 300, the upper separator 400 or the lower separator 500. It is understandable that in the actual winding process, excessive thickness deviation of the positive electrode sheet 200, the negative electrode sheet 300, the upper separator 400 or the lower separator 500 before and after the winding will cause the tab to be misaligned. In the actual implementation of the method provided by the present invention, at least one of the positive electrode sheet 200, the negative electrode sheet 300, the upper separator 400 or the lower separator 500 can be used to measure the first conveying length value L1 and the second conveying length value L2, thereby improving the accuracy of tab error correction and reducing the scrap rate.

[0033] It should be noted that, during the implementation of the method provided by the present invention, if the first conveying length value L1 and the second conveying length value L2 of the positive electrode sheet 200 before and after the roll change are measured, then when adjusting the thickness of the electrode sheet, it is necessary to adjust the thickness of the positive electrode sheet 200; if the first conveying length value L1 and the second conveying length value L2 of the negative electrode sheet 300 before and after the roll change are measured, then when adjusting the thickness of the electrode sheet, it is necessary to adjust the thickness of the negative electrode sheet 300; if the first conveying length value L1 and the second conveying length value L2 of the lower diaphragm 500 or the upper diaphragm 400 before and after the roll change are measured, then when adjusting the thickness of the electrode sheet, it is necessary to adjust the thickness of the positive electrode sheet 200 or the negative electrode sheet 300.

[0034] Optionally, when the output raw material is a positive electrode sheet 200 and / or a negative electrode sheet 300, the length difference ΔL and the thickness compensation value h of the electrode sheet satisfy the relationship: h=((ΔL / (Φ / 360)) / 6.28)*3. When the length difference ΔL and the thickness compensation value h of the electrode sheet satisfy the embodiment of this embodiment, accurate compensation for the misalignment of the tab can be ensured, thereby improving the tab alignment of the battery cell after adjustment.

[0035] Optionally, when the output raw material is the upper diaphragm 400 and / or the lower diaphragm 500, the length difference ΔL and the thickness compensation value h of the pole piece satisfy the relationship: h=((ΔL / (Φ / 360)) / 6.28)*0.035. When the length difference ΔL and the thickness compensation value h of the pole piece satisfy the embodiment of this embodiment, accurate compensation for the misalignment of the pole tab can be ensured, thereby improving the alignment of the pole tabs of the battery cell after adjustment.

[0036] Optionally, when the remaining length L3 of the output material is less than the preset length value L0, the roll change instruction of the winding device is triggered. It is understandable that the remaining length L3 of the output material can be measured by the relevant measuring device on the feed roller, and the measurement of the remaining length L3 of the output material is a function of the existing winding device itself, and there is no need to describe and limit the specific detection method of the remaining length L3 of the output material. By comparing the remaining length L3 of the output material with the preset length value L0, it is possible to issue an instruction in time when the winding device needs to change the roll, thereby facilitating the method provided by the present invention to measure the length of the output material before and after the roll change.

[0037] Further optionally, the preset length value L0 is: 10m-30m. The preset length value L0 can be 10m, 12m, 14m, 16m, 18m, 20m, 22m, 24m, 26m, 28m, 30m. Of course, the preset length value L0 can also select other values ​​within 10m-30m according to actual needs, and is not limited to the above examples. It can be understood that if the preset length L0 is too large, it will cause waste of output raw materials, and if the preset length L0 is too small, the time for subsequent actions after the roll change instruction is issued will be too short, which is easy to increase the roll change failure rate. In this embodiment, the preset length L0 is controlled within the range, which can not only improve the utilization rate of the output raw materials and reduce the waste of output raw materials, but also reserve enough time for subsequent actions after the roll change instruction is issued, thereby reducing the roll change failure rate.

[0038] Optionally, the method for adjusting the thickness of the pole piece is to adjust the pressure of the pole piece shaping roller 700 in the winding device on the pole piece. It can be understood that the pole piece shaping roller 700 is a structure originally existing in the winding device, and the method disclosed in the present invention uses the existing structure in the winding device to adjust the thickness of the pole piece, which means that when implementing the method of the present invention, there is no need to make too many modifications to the winding device, thereby facilitating the embodiment of the method disclosed in the present invention.

[0039] Further optionally, the alignment of the pole lugs is finally improved by adjusting the shaping pressure W (Mpa) of the pole piece shaping roller 700. The relationship between the thickness of the pole piece and the shaping pressure W is as follows:

[0040] The first case: when the shaping pressure W is less than 0.17Mpa, the thickness of the pole piece and the shaping pressure W satisfy the relationship: W1 = h*K1, where K1 is the compensation constant. The value range of K1 is 8-13.5 according to the different compaction of the pole piece model.

[0041] The second case: when the shaping pressure W>0.17Mpa, the thickness of the pole piece and the shaping pressure W satisfy the relationship: W2=h*K2, where K2 is a compensation constant. Depending on the compaction of the pole piece model, the value range of K2 is 3.45-5.5.

[0042] It should be noted here that, according to the foregoing, in the actual control process, after the thickness of the pole piece is calculated based on the length difference ΔL and the preset angle Φ, the specific value of the shaping pressure W is calculated according to the above formula, and then the thickness of the pole piece is adjusted to the theoretically calculated value by adjusting the shaping pressure W, thereby achieving pole ear alignment.

[0043] Taking the above diaphragm roll replacement 400 as an example, the preset angle Φ is set to 5400°, and the preset difference ΔL0 is set to 3 mm.

[0044] Before the roll change, the single roll winding needle 600 rotates the preset angle 5400° and records the first conveying length value L1 of the upper diaphragm 400 as 3696.37mm; after the roll change, the single roll winding needle 600 rotates the preset angle 5400° and records the second conveying length value L2 of the new upper diaphragm 400 as 3693.24mm. The length difference ΔL between the first conveying length value L1 and the second conveying length value L2 is -3.12mm. Substituting into the formula: the thickness compensation value of the pole piece h = ((ΔL / (Φ / 360)) / 6.28)*0.035, it can be obtained that h = -0.0012. Since the length difference ΔL is a negative value, it means that the upper diaphragm 400 after the roll change is thinner than the upper diaphragm 400 before the roll change, so it is necessary to increase the shaping pressure W of the pole piece shaping roller 700. Assuming that the current shaping pressure W = 0.135Mpa, take K1 as 8.5, substitute into the formula W1 = h*K1, W1 = -0.0102Mpa, and it can be concluded that the shaping pressure W of the pole piece shaping roller 700 after the roll change should be 0.135Mpa-(-0.0102Mpa), that is, W = 0.1452Mpa.

[0045] If the length difference ΔL is a positive value, it means that the upper diaphragm 400 after the roll change is completed is thicker than the upper diaphragm 400 before the roll change, and then the shaping pressure W of the pole piece shaping roller 700 needs to be reduced.

[0046] In addition, in order to achieve visual display or manual adjustment of the first conveying length value L1, the second conveying length value L2, the length difference ΔL, the preset difference ΔL0, the thickness of the pole piece, and the preset angle Φ, a display panel of the above parameters can be added to the existing winding equipment, so as to facilitate the operator to have a more intuitive understanding of the misalignment and alignment of the pole lugs.

[0047] 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.

[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for improving the alignment of tabs of a wound battery, characterized in that: The steps include: When the roll change instruction of the winding device is triggered, the single roll winding needle rotates by a preset angle Φ and then records the first conveying length value L1 of the output raw material; After the raw material roll is replaced, after the single roll winding needle rotates the preset angle Φ, the second conveying length value L2 of the raw material output after the roll is replaced is recorded; When the absolute value of the length difference ΔL between the first conveying length value L1 and the second conveying length value L2 exceeds the preset difference ΔL0, it is determined that the tab has a deviation; The thickness of the pole piece is adjusted according to the length difference ΔL.

2. The method for improving the alignment of the tabs of a wound battery according to claim 1, characterized in that: The range of the preset difference ΔL0 is: 1mm-5mm.

3. The method for improving the alignment of the tabs of a wound battery according to claim 1, characterized in that: The length difference ΔL and the thickness compensation value h of the pole piece satisfy the relationship: h=((ΔL / (Φ / 360)) / 6.28)*Q, where Q is a compensation constant and the range is 0.01-5.

4. The method for improving the alignment of the tabs of a wound battery according to claim 1, characterized in that: The range of the preset angle Φ is: 1080°-5400°.

5. The method for improving the alignment of the tabs of a wound battery according to any one of claims 1 to 4, characterized in that: The output raw material includes at least one of a positive electrode sheet, a negative electrode sheet, an upper separator or a lower separator.

6. The method for improving the alignment of tabs of a wound battery according to claim 5, characterized in that: When the output raw material is the positive electrode sheet and / or the negative electrode sheet, the length difference ΔL and the thickness compensation value h of the electrode sheet satisfy the relationship: h=((ΔL / (Φ / 360)) / 6.28)*3.

7. The method for improving the alignment of tabs of a wound battery according to claim 5, characterized in that: When the output raw material is the upper diaphragm and / or the lower diaphragm, the length difference ΔL and the thickness compensation value h of the pole piece satisfy the relationship: h=((ΔL / (Φ / 360)) / 6.28)*0.

035.

8. The method for improving the alignment of the tabs of a wound battery according to any one of claims 1 to 4, characterized in that: When the remaining length L3 of the output raw material is less than the preset length value L0, the roll changing instruction of the winding device is triggered.

9. The method for improving the alignment of tabs of a wound battery according to claim 8, characterized in that: The preset length value L0 is: 10m-30m.

10. The method for improving the alignment of the tabs of a wound battery according to any one of claims 1 to 4, characterized in that: The method for adjusting the thickness of the pole piece is to adjust the pressure of the pole piece shaping roller in the winding device on the pole piece.

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