Diaphragm rolling core

Abstract

The utility model discloses a diaphragm winding core which comprises a hard winding core, a buffer layer and a wrapping layer which are concentrically arranged in sequence from inside to outside. The buffer layer comprises an inflation buffer sleeve, and the inflation buffer sleeve comprises an inflation buffer layer and an inflation structure used for inflating and deflating the inflation buffer layer. In an inflation state, the inflation buffer layer is in interference fit with the hard roll core and the wrapping layer which are located on the two radial sides of the inflation buffer layer. According to the diaphragm winding roll core provided by the utility model, in an inflation state, the inflation buffer layer is in interference fit with the hard roll core and the wrapping layer which are positioned on the two radial sides of the inflation buffer layer. After the diaphragm is rolled and air is exhausted from the inflation end of the inflation buffer sleeve, the volume of the inflation buffer sleeve is contracted, the wrapping layer located on the periphery of the inflation buffer sleeve collapses and contracts along with the inflation buffer sleeve, at the moment, the diaphragm rolling core can be pulled out from the center of the diaphragm roll, and the inflation buffer sleeve and the wrapping layer which are pulled out are separated from the hard roll core. And the inflatable cushion collar and the wrapping layer are folded and stored in a special transfer container and are returned to a diaphragm production factory, so that repeated utilization is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery preparation, and more specifically, to a diaphragm winding core. Background Art

[0002] As one of the key components of lithium-ion batteries, the diaphragm isolates the positive and negative electrodes of the battery and prevents short circuits. Therefore, the performance and quality of the diaphragm play a crucial role in the performance and safety of lithium-ion batteries. During the production of lithium-ion battery diaphragms, thickness deviations and tension differences in the diaphragm products lead to certain internal stresses in the rolled diaphragm products. If these internal stresses cannot be effectively released, the diaphragm products will have more defects, such as ribs, collapsed edges, and tire marks, affecting the product's yield rate. These defects may further prevent the positive and negative electrodes of the lithium-ion battery from being completely separated, leading to safety issues such as short circuits.

[0003] An existing diaphragm winding core includes a core tube and a buffer layer connected to the outer surface of the core tube. The winding core also includes a wrapping layer wrapped around the buffer layer. The buffer layer includes a plurality of buffer strips, and the plurality of buffer strips are connected to the outer surface of the core tube at intervals along the circumferential direction of the core tube. The wrapping layer surrounds the buffer layer at least once. Although the existing diaphragm winding core of this type wraps a wrapping layer outside the buffer layer on the basis of the buffer layer of the core tube and its outer surface, it can not only alleviate the deformation of the membrane surface caused by the internal stress of the diaphragm, but also alleviate the bottom wrinkling phenomenon caused by the contact and compression of the bottom diaphragm and the buffer layer during the diaphragm stress release process. However, after the winding is completed using this diaphragm winding core, the diaphragm wrapped around the outer circumference of the diaphragm winding core cannot be recycled.

[0004] Therefore, how to provide a recyclable membrane winding core has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0005] The utility model aims to provide a diaphragm winding core which can be recycled.

[0006] The utility model provides a membrane winding core, comprising a hard winding core, a buffer layer and a wrapping layer which are concentrically arranged from the inside to the outside:

[0007] The buffer layer includes an inflatable buffer sleeve, and the inflatable buffer sleeve includes an inflatable buffer layer and an inflatable structure for inflating and deflating the inflatable buffer layer;

[0008] In the inflated state, the inflatable buffer layer is interference-fitted with the hard winding core and the wrapping layer located on both sides of the inflatable buffer layer in the radial direction.

[0009] Optionally, the inflatable buffer layer includes inflatable buffer strips, and a plurality of inflatable buffer strips are sequentially arranged along the circumference of the hard winding core.

[0010] Optionally, when the inflatable buffer layer is unfolded into a rectangle, the wide side extension direction of the inflatable buffer layer is the axis extension direction of the hard winding core;

[0011] The inflatable buffer strip is arranged obliquely to the wide side, and the angle between the two is between 15° and 50°.

[0012] Optionally, two adjacent inflatable buffer strips are bonded to each other.

[0013] Optionally, the width of the inflatable buffer strip is 20 mm-100 mm.

[0014] Optionally, the inflatable structure includes an annular inflatable channel, and the two annular inflatable channels are respectively arranged at two axial ends of the inflatable buffer layer, and the annular inflatable channels are interconnected with all the inflatable buffer strips.

[0015] Optionally, the wrapping layer includes an elastic sheath, and / or the inflatable cushioning sheath is made of a flexible material.

[0016] Optionally, the inflatable buffer sleeve and the elastic sheath are made of a polymer rubber-plastic material or a rubber composite material.

[0017] Optionally, when the gas in the inflatable buffer sleeve is exhausted, the inflatable buffer sleeve is separated from the hard winding core and the wrapping layer located on both sides of the inflatable buffer sleeve in the radial direction.

[0018] Optionally, the hard roll core is configured as a circular hollow structure, and the material is one of kraft paper or resin.

[0019] According to the technical content disclosed in this utility model, the following beneficial effects are achieved:

[0020] The utility model provides a membrane winding core, wherein the buffer layer includes an inflatable buffer sleeve, which includes an inflatable buffer layer and an inflatable structure for inflating and deflating the inflatable buffer layer. In the inflated state, the inflatable buffer layer has an interference fit with the hard winding core and the wrapping layer located on both radial sides thereof. After the membrane is wound, the air is discharged from the inflatable end of the inflatable buffer sleeve, causing the volume of the inflatable buffer sleeve to shrink, and the wrapping layer located on the outer periphery of the inflatable buffer sleeve to collapse and shrink accordingly. At this time, the membrane winding core can be pulled out from the center of the membrane roll, and the inflatable buffer sleeve and wrapping layer can be separated from the hard winding core after being pulled out. The inflatable buffer sleeve and wrapping layer can be folded and stored in a dedicated transport container, and then returned to the membrane production factory for reuse.

[0021] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0023] Figure 1 This is a schematic axial cross-sectional view of the diaphragm winding core of the utility model;

[0024] Figure 2 It is a partial cross-sectional schematic diagram of the diaphragm winding core of the utility model;

[0025] Figure 3 It is a radial cross-sectional schematic diagram of the diaphragm winding core of the utility model.

[0026] Explanation of the accompanying reference numerals: 1. Hard winding core; 2. Inflatable cushioning sleeve; 3. Elastic sheath; 21. Inflating nozzle; 22. Annular inflation channel; 23. Inflatable cushioning strip; 24. Bonding area. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0028] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0029] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0031] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] See also Figure 1 and Figure 3The utility model discloses a diaphragm winding core, comprising a hard core 1, a buffer layer and a wrapping layer which are concentrically arranged from the inside to the outside; the hard core 1 is arranged as a circular hollow structure, and the material is one of kraft paper or resin. The buffer layer is an inflatable buffer sleeve 2, which comprises an inflatable buffer layer and an inflatable structure for inflating and deflating the inflatable buffer layer; the inflatable buffer layer adopts a two-layer structure, one layer is close to the hard core 1, and the other layer is close to the wrapping layer, and the space between the two layers can be inflated to form a buffer structure; air of a certain pressure is filled into the space between the two layers through the inflatable structure. In the inflated state, the inflatable buffer layer and the hard core 1 and the wrapping layer located on both sides of the inflatable buffer layer have an interference fit, and the friction resistance with the hard core 1 during inflation prevents slipping; the elastic sheath 3 is sleeved on the outer surface of the inflatable buffer sleeve 2, and when the inflatable buffer sleeve 2 is inflated, the elastic sheath 3 is tightened and fixed to it, and the outer surface of the elastic sheath 3 is in direct contact with the diaphragm. When the air within the inflatable cushioning sleeve 2 is exhausted, it shrinks and separates from the rigid core 1 and the wrapping layer located radially on either side of it. The wrapping layer includes an elastic sheath 3. The elastic sheath 3 and the inflatable cushioning sleeve 2 are made of a flexible material. After the air is exhausted, they can be folded or flattened and stacked for multiple reuse. In this embodiment, the inflatable cushioning sleeve 2 and the elastic sheath 3 are made of a polymer rubber-plastic material or a rubber composite material.

[0033] Combine Figure 2 The inflatable buffer layer includes a plurality of inflatable buffer strips 23, which are arranged in sequence along the circumference of the rigid core 1. The width of the inflatable buffer strips 23 is 20mm-100mm. Two adjacent inflatable buffer strips 23 are bonded to each other by glue in the bonding area 24. In some embodiments, two adjacent inflatable buffer strips 23 are bonded by hot melt bonding, specifically bonding for rubber and hot melt for plastic. The inflatable structure includes an annular inflatable channel 22, two annular inflatable channels 22 are respectively arranged at the axial ends of the inflatable buffer layer, and the annular inflatable channels 22 are interconnected with the plurality of inflatable buffer strips 23. At least one of the annular inflatable channels 22 is provided with an inflating nozzle 21, which is used to adjust the pressure of the inflatable buffer layer, that is, to inflate or deflate the inflatable buffer sleeve 2. The elastic sheath 3 is used to compensate for the concave structure formed between the inflatable buffer strips 23. An elastic sheath is put on the outside of the inflatable buffer sleeve 2 to smoothly transition the concave structure between the inflatable buffer strips 23. The elastic sheath 3 is made of a polymer rubber-plastic material or a rubber composite material, and can provide good support for the diaphragm.

[0034] Furthermore, when the inflatable buffer layer is unfolded into a rectangle, the wide side extension direction of the inflatable buffer layer is the axial extension direction of the hard winding core 1; the inflatable buffer strip 23 is arranged obliquely to the wide side, and the angle between the two is between 15° and 50°.

[0035] It should be noted that the commonly used diaphragm winding methods on the market at this stage include two methods: a hard winding core and coating the surface of the hard winding core with a layer of foam material.

[0036] The former type of rigid core is made of kraft paper or resin. Kraft paper is wound into a paper tube, or the resin is injection molded. These rigid cores have high surface rigidity, making it difficult to release the internal stress of the diaphragm during winding, resulting in a high defect rate in the diaphragm products.

[0037] The latter is a foam material coated on the surface of a hard core, usually one of EVA, polyurethane, and PE. This core uses the foaming process of the material to form a gas microporous structure inside the material. The gas generated by the foaming process is stored inside the gas microporous structure, so this structure has the characteristic of being compressible. When the diaphragm is rolled up, the gas microporous structure ruptures and discharges the gas, and the volume changes. In this way, the internal stress of the rolling process is released. Compared with the previous method, the defect rate of the diaphragm product is greatly reduced in this way. However, after the gas microporous structure of the foaming material discharges the gas, the volume compression elasticity is lost, resulting in the core being non-reusable, and this type of core is of greater value, resulting in increased production costs. The utility model uses an inflatable buffer sleeve 2 as a buffer layer. After the inflatable buffer sleeve 2 is subjected to force, it compresses the air inside, which will not cause damage to the buffer layer structure, so it can be used multiple times.

[0038] In summary, compared with the prior art, the membrane winding core of this embodiment comprises a rigid core 1, an inflatable cushioning sleeve 2, and an elastic sheath 3. The inflatable cushioning sleeve 2 is sheathed on the outside of the rigid core 1, and the elastic sheath 3 is sheathed on the outside of the inflatable cushioning sleeve 2. The size of the rigid core 1 with a circular hollow structure matches the fixture of the slitting equipment and provides rigid support for the membrane winding core of this embodiment. The inflatable cushioning sleeve 2 serves as the main body for releasing internal stress. Utilizing the compressible property of air, when a local area is subjected to greater pressure, the corresponding position of the inflatable cushioning sleeve 2 undergoes a certain deformation to provide space for pressure release. During the diaphragm winding process, in order to effectively expel the air between the diaphragms, a pressure roller is usually set on the equipment. The pressure roller needs to maintain the squeezing state of the diaphragm during the entire winding process and needs to have a flat contact surface. The elastic sheath 3 provides a flat contact surface for the diaphragm winding. Since there is a certain depression between the inflatable buffer strips 23 of the inflatable buffer sleeve 2, if there is no elastic sheath 3, the diaphragm will be pressed into the depression by the winding pressure roller during winding, causing wrinkles in the diaphragm. The presence of the elastic sheath 3 can not only prevent the diaphragm from being pressed into the depression, but also provide a flat contact space for the pressure roller to contact the diaphragm so that the air between the diaphragms can be emptied. When the diaphragm is wound, the local internal stress of the rolled diaphragm is transmitted to the inflatable buffer sleeve 2 through the elastic sheath 3. The inflatable buffer sleeve 2 and the elastic sheath 3 then undergo local deformation to release the local concentrated internal stress, thereby avoiding changes in the flatness of the diaphragm caused by the internal stress concentration, which affects the quality of the diaphragm product. Since the inflatable buffer sleeve 2 and the elastic sleeve 3 are both made of flexible materials, the inflatable buffer sleeve 2 and the elastic sleeve 3 can be separated from the hard core 1 by emptying the air in the inflatable buffer sleeve 2. The inflatable buffer sleeve 2 and the elastic sleeve 3 are transported to the diaphragm production enterprise after proper protection to achieve reuse, thereby effectively reducing production costs.

[0039] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art will appreciate that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art will appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A membrane winding core, comprising a hard winding core, a buffer layer, and a wrapping layer, which are concentrically arranged from the inside to the outside, characterized in that: The buffer layer includes an inflatable buffer sleeve, and the inflatable buffer sleeve includes an inflatable buffer layer and an inflatable structure for inflating and deflating the inflatable buffer layer; In the inflated state, the inflatable buffer layer and the hard winding core and the wrapping layer located on both sides of the inflatable buffer layer in radial direction are interference fit.

2. The membrane winding core according to claim 1, characterized in that: The inflatable buffer layer includes inflatable buffer strips, and a plurality of the inflatable buffer strips are sequentially arranged along the circumference of the hard winding core.

3. The membrane winding core according to claim 2, characterized in that: When the inflatable buffer layer is unfolded into a rectangle, the wide side extension direction of the inflatable buffer layer is the axial extension direction of the hard winding core; The inflatable buffer strip is arranged obliquely to the wide side, and the angle between the two is between 15° and 50°.

4. The membrane winding core according to claim 2, characterized in that: Two adjacent inflatable buffer strips are bonded to each other.

5. The membrane winding core according to claim 2, characterized in that: The width of the inflatable buffer strip is 20mm-100mm.

6. The membrane winding core according to any one of claims 2 to 5, characterized in that: The inflatable structure includes an annular inflatable channel. Two annular inflatable channels are respectively arranged at two axial ends of the inflatable buffer layer. The annular inflatable channels are interconnected with all the inflatable buffer strips.

7. The membrane winding core according to any one of claims 1 to 5, characterized in that: The wrapping layer includes an elastic sheath, and / or the inflatable cushioning sheath is made of a flexible material.

8. The membrane winding core according to claim 7, characterized in that: The inflatable buffer sleeve and the elastic protective sleeve are made of high molecular rubber and plastic material or rubber composite material.

9. The membrane winding core according to any one of claims 1 to 5, characterized in that: When the gas in the inflatable buffer sleeve is exhausted, the inflatable buffer sleeve is separated from the hard winding core and the wrapping layer located on both sides thereof in the radial direction.

10. The membrane winding core according to any one of claims 1 to 5, characterized in that: The hard winding core is configured as a circular hollow structure, and the material is one of kraft paper or resin.

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