Multi-layer pole piece winding device and winding method

Abstract

The invention relates to a multi-layer pole piece winding device and a winding method, and belongs to the technical field of battery winding equipment. The device comprises a winding needle and at least four pairs of feeding driving rollers arranged around the winding needle; the positive plate and the negative plate are arranged between the feeding driving rollers at intervals, and a diaphragm is arranged between the positive plate and the negative plate; and the positive plate, the negative plate and the diaphragm are simultaneously wound on the winding needle through the feeding driving roller. And the length of the outer-layer pole piece is greater than that of the inner-layer pole piece. A pair of positive and negative pole pieces and two diaphragms form a winding unit, and 2-6 winding units are arranged around the winding needle. The method comprises the following steps: performing die cutting to obtain positive and negative plates; the positive and negative pole pieces are respectively conveyed to adjacent pairs of feeding driving rollers and are separated by diaphragms; and the feeding driving roller is started to simultaneously feed the positive and negative pole pieces and the diaphragm to the winding needle for winding. The pole piece length can be reduced, the number of winding turns is reduced, the winding efficiency is improved, and the pole lug alignment precision is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery winding equipment, and relates to a multi-layer electrode sheet winding device and a winding method. Background Art

[0002] In the wave of the rapid development of the current battery industry, the improvement of winding equipment efficiency and the improvement of tab alignment accuracy have become the core trends driving the industry forward. At present, the mainstream winding method in the industry is to wind with a negative electrode sheet and a positive electrode sheet fed synchronously, and then complete the manufacture of the winding core. However, this traditional winding method is facing increasingly severe technical bottlenecks in terms of winding efficiency and tab alignment control.

[0003] From the perspective of winding efficiency, the winding tension control ability and the upper limit of the electrode sheet winding line speed become two key limiting factors. In the dynamic process of winding, the stable control of tension is like a precise balancing art, which plays a decisive role in ensuring the flatness of the electrode sheet and avoiding wrinkles and fractures. However, the existing tension control technologies are still difficult to achieve more precise and efficient operations. When the electrode sheet is in a high-speed winding state, due to the instability of tension control, the electrode sheet is extremely prone to problems such as deformation, wrinkles, and even fractures, which not only affect the quality of the winding core but also reduce the production efficiency.

[0004] At the same time, the increase in the electrode sheet winding line speed also encounters numerous difficulties. The stability of the equipment mechanical structure is one of the important factors restricting the increase in the line speed. Under high-speed operation, problems such as wear and vibration of mechanical components will become more prominent, thereby affecting the winding accuracy and stability. The accuracy of power transmission cannot be ignored either. Minor errors in the transmission system may cause the displacement of the electrode sheet position, affecting the winding quality. These factors are intertwined and jointly limit the further improvement of winding efficiency.

[0005] In terms of tab alignment control, with the continuous increase in the demand for the capacity of single-cell batteries in the power and energy storage fields, the problem has become increasingly prominent. The increase in the length of the electrode sheet results in an increase in the number of winding turns, and the difficulty of tab alignment control also increases exponentially. The main source of tab alignment deviation lies in the fluctuation between the actual thickness and the designed thickness of the electrode sheet. During the multi-layer winding process, this fluctuation is continuously superimposed, forming an accumulation effect. As the number of winding turns increases, the deviation accumulation effect becomes more obvious, ultimately leading to a significant decrease in the tab alignment accuracy.

[0006] The reduction in the alignment accuracy of the tabs severely restricts the increase in the capacity of single cells. In the fields of power and energy storage, large-capacity single cells have higher energy density and longer service life, which are the urgent needs of market development. However, due to insufficient tab alignment accuracy, problems such as increased internal resistance and severe heating are likely to occur during the charging and discharging process of the cell, affecting the performance and safety of the cell, thus limiting the further increase in the capacity of single cells.

[0007] The development of battery winding equipment is at a critical stage. Breaking through the existing technical bottlenecks and improving the winding efficiency and tab alignment accuracy will inject strong impetus into the sustainable development of the battery industry and lead the industry to a new height. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a multi-layer electrode winding device and a winding method, which can improve the winding efficiency, enhance the control accuracy of tab alignment, and effectively break through the bottleneck of the above technical problems.

[0009] To achieve the above purpose, the present invention provides the following technical solutions:

[0010] A multi-layer electrode winding device includes a winding needle and at least four pairs of feeding driving rollers arranged around the winding needle; a positive electrode sheet and a negative electrode sheet are arranged at intervals between the feeding driving rollers, and a separator is arranged between the positive electrode sheet and the negative electrode sheet; the positive electrode sheet, the negative electrode sheet, and the separator are simultaneously wound around the winding needle through the feeding driving rollers.

[0011] Optionally, the length of the outer electrode sheet is greater than the length of the inner electrode sheet.

[0012] Optionally, one positive electrode sheet, one negative electrode sheet, and two separators form a winding unit, and 2 to 6 winding units are arranged around the winding needle.

[0013] Optionally, the arrangement order of the electrode sheets in each winding unit is: from the inside to the outside, they are separator, positive electrode sheet, separator, and negative electrode sheet in sequence.

[0014] Optionally, the arrangement order of the electrode sheets in each winding unit is: from the inside to the outside, they are positive electrode sheet, separator, negative electrode sheet, and separator in sequence.

[0015] Optionally, the thickness of one winding unit is 200 to 350 μm.

[0016] Optionally, the diameter of the winding needle is 5 to 15 mm.

[0017] Optionally, the length of the electrode sheet is 0.3 to 15 m.

[0018] A multi-layer electrode winding method, applying the winding device described in any one of the above, includes the following steps:

[0019] S1. Obtain several pairs of positive electrode sheets and negative electrode sheets respectively through mechanical die cutting or laser die cutting;

[0020] S2. Transmit the positive electrode sheets and negative electrode sheets to the feeding drive rollers of adjacent pairs respectively, and arrange a separator between each pair of positive electrode sheets and negative electrode sheets;

[0021] S3. Start all the feeding drive rollers simultaneously, feed the positive electrode sheets, negative electrode sheets, and separator to the winding needle simultaneously, and complete the manufacturing of the core by winding simultaneously.

[0022] Optionally, before the winding operation starts, each layer of electrode sheet is separately subjected to unwinding deviation correction, process deviation correction, and feeding deviation correction.

[0023] The beneficial effects of the present invention are as follows:

[0024] The present invention feeds multiple layers of positive and negative electrode sheets simultaneously and winds them simultaneously to manufacture the core. Compared with the traditional winding method of simultaneously winding one layer of negative electrode sheet and one layer of positive electrode sheet (such as Figure 1 , 2 ), the present invention can shorten the length of the electrode sheet by half, reduce the number of winding turns by half, and improve the winding efficiency. It effectively reduces the length of the electrode sheet, reduces the number of winding turns, and improves the winding efficiency.

[0025] The deviation of the tab alignment is mainly caused by the superposition of fluctuations between the actual thickness and the designed thickness of the electrode sheet through layer-by-layer winding. The number of winding turns is strongly correlated with the tab alignment accuracy. Reducing the number of winding turns can effectively improve the tab alignment accuracy. Whether it is constant-speed winding or constant-linear-speed winding, the winding efficiency will be greatly improved. Considering the factors of acceleration and deceleration of the electrode sheet during the winding process, when four layers of electrode sheets are fed and wound simultaneously, referring to the 2.5m long electrode sheet, the winding efficiency can be increased by more than 50%; only considering the tab alignment, the capacity of a single cell can be increased to 110% - 135%.

[0026] The present invention defines that the designed length of the negative electrode sheet is longer than that of the positive electrode sheet. When winding, the length of the inner layer electrode sheet closer to the winding needle is designed shorter, and the length of the outer layer electrode sheet is designed longer, so as to ensure the coating of the positive and negative electrode sheets at the head and tail of the core. Before the winding operation starts, each layer of electrode sheet needs to be separately subjected to unwinding deviation correction, process deviation correction, and feeding deviation correction, so as to ensure the coating accuracy of the positive and negative electrodes and the separator.

[0027] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following specification. Description of the Drawings

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail preferably below in conjunction with the accompanying drawings, where:

[0029] Figure 1 It is a schematic diagram of a feeding mechanism of an existing winding device;

[0030] Figure 2 It is a schematic diagram of an existing battery winding process;

[0031] Figure 3 It is a schematic diagram of a winding device of the present invention;

[0032] Figure 4 It is a schematic diagram of a winding process of the present invention;

[0033] Figure 5 It is a schematic diagram of five winding units of the present invention.

[0034] Reference numerals:

[0035] 1 winding needle, 2 positive electrode sheet, 3 negative electrode sheet, 4 separator, 5 feeding driving roller. Specific embodiments

[0036] The following illustrates the embodiments of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0037] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, rather than physical diagrams, and should not be construed as a limitation on the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0038] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the accompanying drawings are only for illustrative purposes and should not be construed as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0039] Please refer to Figures 3 to 5 , which is a multi-layer pole piece winding device and a winding method.

[0040] The winding device includes a winding needle 1 and at least four pairs of feeding driving rollers 5 arranged around the winding needle 1; the positive pole piece 2 and the negative pole piece 3 are arranged at intervals between the feeding driving rollers 5, and a separator 4 is arranged between the positive pole piece 2 and the negative pole piece 3; the positive pole piece 2, the negative pole piece 3, and the separator 4 are simultaneously wound around the winding needle 1 by the feeding driving rollers 5. One positive pole piece 2, one negative pole piece 3, and two separators 4 form a winding unit; under the condition of ensuring that the separator 4 completely covers the negative pole piece 2 and the negative pole piece 2 completely covers the positive pole piece 2, the setting order of the pole pieces in each winding unit is: from the inside to the outside, they are the separator 4, the positive pole piece 2, the separator 4, the negative pole piece 3, or from the inside to the outside, they are the positive pole piece 2, the separator 4, the negative pole piece 3, the separator 4; 2 to 6 winding units are arranged around the winding needle 1; the thickness of one winding unit is 200 to 350 μm.

[0041] The length of the outer layer pole piece is greater than the length of the inner layer pole piece to ensure the coating of the positive and negative pole pieces at the head and tail of the winding core. The specific design of the pole piece length also needs to be considered according to the specific diameter of the winding needle 1, the pole piece thickness, and the number of winding turns.

[0042] Different from the layout in the conventional winding process where 2 pieces of negative pole pieces are on the outer layer and 2 pieces of positive pole pieces are on the inner layer, and the design where the length of the negative pole piece is greater than the length of the positive pole piece, in the multi-layer winding process of the present invention, there is a relative situation where 2 pieces of positive pole pieces are on the outer layer and 2 pieces of negative pole pieces are on the inner layer inside the winding core. In the present invention, the length of the outer layer negative pole piece 2 is greater than the length of the inner layer negative pole piece 2, and the length of the outer layer positive pole piece 2 is greater than the length of the inner layer positive pole piece 2; the length of the innermost layer negative pole piece 2 is greater than the length of the innermost layer positive pole piece 2, and the length of the outermost layer negative pole piece 2 is greater than the length of the outermost layer positive pole piece 2; the length of the positive pole piece 2 in the relatively outer layer is greater than the length of the negative pole piece 2 in the relatively inner layer and meets the design that the negative pole piece 2 completely covers the positive pole piece 2.

[0043] The winding method includes the following steps:

[0044] S1. Obtain a number of pairs of positive electrode sheets 2 and negative electrode sheets 3 with different designed sheet lengths respectively through mechanical die cutting or laser die cutting;

[0045] S2. Transport the positive electrode sheets 2 and negative electrode sheets 3 to the feeding drive rollers 5 of adjacent pairs respectively, and arrange a separator 4 between each pair of positive electrode sheets 2 and negative electrode sheets 3 to separate them;

[0046] S3. Start all the feeding drive rollers 5 simultaneously, feed the positive electrode sheets 2, negative electrode sheets 3, and separator 4 to the winding needle 1 simultaneously, and complete the manufacture of the core by winding at the same time.

[0047] Before the winding operation starts, each layer of electrode sheet is separately unrolled for deviation correction, process deviation correction, and feeding deviation correction to ensure the coating accuracy of the positive and negative electrodes and the separator 4.

[0048] Example 1:

[0049] Taking the winding process of a traditional 46 - series large - cylindrical battery with an electrode sheet length of 5m and 70 winding turns as an example. If the device and method of the present invention are adopted and four - layer electrode sheets are selected for simultaneous feeding and winding, the side length of the positive and negative electrode sheets 3 can be designed to be about 2.5m (according to the need for coating of the positive and negative electrodes, the inner - layer electrode sheets close to the winding needle 1 are slightly shorter, and the outer - layer electrode sheets are slightly longer). The number of winding turns only needs 35 turns. Not only is the electrode sheet length half of the traditional method, but the number of winding turns can also be reduced by half. Whether it is constant - speed winding or constant - line - speed winding, the winding efficiency will be greatly improved. Considering the factors of acceleration and deceleration of the electrode sheet during the winding process, when four - layer electrode sheets are simultaneously fed and wound, the winding efficiency can be increased by more than 50%.

[0050] Example 2:

[0051] Taking the square - shell wound battery in the field of power and energy storage as an example, the number of winding turns is 20 - 50 turns, the total thickness of the positive electrode sheet 2 plus the negative electrode sheet 3 plus two layers of separator 4 is 200 - 350μm, and the diameter of the winding needle 1 is 5 - 15mm. If the device and method of the present invention are adopted and a process of simultaneously feeding and winding four - layer electrode sheets is used, under the condition of ensuring the same ear alignment accuracy, by reducing the number of winding turns, the electrode sheet length can be designed to be 1.09 - 1.33 times the electrode sheet length of the traditional process (the electrode sheet length is 0.3 - 15m). Simultaneously feeding and winding four - layer electrode sheets can improve the winding efficiency, ear alignment accuracy, and single - cell capacity simultaneously by reducing a certain number of winding turns and increasing a certain electrode sheet length.

[0052] Example 3:

[0053] By optimizing the mechanism design of the bobbin 1 for changing workstations, attaching the end glue to the bobbin core, and discharging the bobbin core, as well as arranging the spatial layout of the winding equipment reasonably. The pole piece feeding mechanism of the winding equipment can be optimized to be designed into 2 to 6 pairs. According to the multi-layer winding process of the pole piece, for each additional pair of pole piece feeding mechanisms designed in the winding equipment, the winding efficiency, the alignment accuracy of the pole ears, and the upper limit of the single cell capacity will increase exponentially compared with Example 1 and Example 2, and there will be a more significant improvement in the above-mentioned technical bottlenecks of winding.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A multi-layer electrode winding device, characterized in that: It includes a winding needle (1) and at least four pairs of feeding drive rollers (5) arranged around the winding needle (1); the positive electrode plates (2) and negative electrode plates (3) are arranged at intervals between the feeding drive rollers (5), and a separator (4) is arranged between the positive electrode plates (2) and negative electrode plates (3); the positive electrode plates (2), negative electrode plates (3), and separator (4) are simultaneously wound around the winding needle (1) by the feeding drive rollers (5).

2. The multi-layer electrode winding device according to claim 1, wherein: The length of the outer-layer electrode plate is greater than that of the inner-layer electrode plate.

3. The multi-layer electrode winding device according to claim 1, wherein: One positive electrode plate (2), one negative electrode plate (3), and two separators (4) form a winding unit, and 2 to 6 winding units are arranged around the winding needle (1).

4. The multi-layer pole piece winding device according to claim 3, wherein: The thickness of one winding unit is 200 to 350 μm.

5. The multi-layer electrode winding device according to claim 3, characterized in that: The arrangement order of the electrode plates in each winding unit is: from the inside to the outside, they are the separator (4), positive electrode plate (2), separator (4), and negative electrode plate (3) in sequence.

6. The multi-layer electrode winding device according to claim 3, characterized in that: The arrangement order of the electrode plates in each winding unit is: from the inside to the outside, they are the positive electrode plate (2), separator (4), negative electrode plate (3), and separator (4) in sequence.

7. The multi-layer pole piece winding device according to claim 1, characterized in that: The diameter of the winding needle (1) is 5 to 15 mm.

8. The multi-layer pole piece winding device according to claim 1, wherein: The sheet length of the electrode plate is 0.3 to 15 m.

9. A multi-layer electrode plate winding method, which applies the winding device according to any one of claims 1 to 8, and is characterized in that: It includes the following steps: S1. Obtain several pairs of positive electrode plates (2) and negative electrode plates (3) respectively by mechanical die-cutting or laser die-cutting; S2. Transmit the positive electrode plates (2) and negative electrode plates (3) to the adjacent pairs of feeding drive rollers (5) respectively, and arrange a separator (4) between each pair of positive electrode plates (2) and negative electrode plates (3) to separate them; S3. Simultaneously start all the feeding drive rollers (5), feed the positive electrode plates (2), negative electrode plates (3), and separator (4) to the winding needle (1) simultaneously, and simultaneously wind to complete the manufacture of the winding core.

10. The multi-layer electrode winding method according to claim 9, wherein: Before the winding work starts, each layer of electrode plate is separately subjected to unwinding deviation correction, process deviation correction, and feeding deviation correction.

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