WO2022143233A1 - Lithium battery separator winding device and process - Google Patents

Abstract

A separator winding device comprising a winding tube core (2) and a heat-shrinkable sleeve (1), which separator winding device relates to the field of lithium battery separators. The inner side of the winding tube core (2) is of a circular ring shape, and the outer side thereof is provided with equal-height protrusions; and the heat-shrinkable sleeve (1) is sleeved on the winding tube core (2). The heat-shrinkable sleeve (1) is subjected to heat shrinking at 65ºC-90ºC, so that the outer diameter of the heat-shrinkable sleeve (1) is reduced by 4 mm-10 mm. After a separator is wound around the separator winding device, the separator is heated at 65ºC-90ºC, and is left for 12 h-36 h at 25ºC-45ºC so as to be subjected to aging placement, and then the separator that has been subjected to aging placement is wound. The material of the heat-shrinkable sleeve (1) is in a glassy state at room temperature and changes to a high-elastic state after being heated. In the process of realizing a heat shrinking treatment, the heat-shrinkable sleeve (1) shrinks inwards, and the outer diameter of the heat-shrinkable sleeve (1) is reduced. By means of the present device, the situations of separator deformation and edge collapse during an internal stress release process of separators that are caused by the fact that the separators press one another and the separators press a winding core due to shrinkage can be greatly alleviated, and the adverse phenomena of rib forming and wrinkling caused by the uneven release of internal stress of the separators are prevented.

Description

A lithium battery separator winding device and process

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese Patent Application No. CN 202011623539.4 and titled "A Lithium Battery Separator Winding Device and Process" filed with the China Patent Office on December 31, 2020, the entire contents of which are incorporated by reference in in this application.

technical field

The present disclosure relates to the field of lithium battery separators, in particular to a lithium battery separator winding device and process.

Background technique

During the production and manufacture of lithium-ion battery separators, there are problems such as uneven stretching and uneven thermal history, resulting in uneven residual internal stress of the lithium-ion battery separator, and the internal stress begins to release during the winding process of the separator, resulting in the formation of the separator. Deformation, slump, deformation, rib, fold and other problems; whether the diaphragm is directly re-cut or coated, it will lead to unqualified base film and coated products, resulting in an increase in the manufacturing cost of the enterprise.

Although there is a conventional method of absorbing the internal stress of the diaphragm by winding the buffer cotton on the outer layer of the core, the problem of diaphragm compression is still serious.

SUMMARY OF THE INVENTION

The present disclosure provides a lithium battery diaphragm winding device, comprising a winding tube core and a heat shrinkable sleeve; the inner side of the winding tube core is annular and the outside is convex; the heat shrinkable sleeve is sleeved on the on the winding core.

In some embodiments, the heat shrinkable sleeve is thermally shrunk at 65°C to 90°C, so that the distance from the outer layer of the heat shrinkable sleeve to the center point of the annular shape inside the winding tube core is reduced by 4 to 10 mm.

In some embodiments, the heat shrink sleeve is a single wall heat shrink sleeve or a double wall heat shrink sleeve.

In some embodiments, the single-wall heat-shrinkable sleeve includes PVC heat-shrinkable sleeve, EVA heat-shrinkable sleeve, and PET heat-shrinkable sleeve.

In some embodiments, the double-wall heat-shrinkable sleeve is a double-wall heat-shrinkable sleeve containing an adhesive layer, the outer layer is polyolefin, and the inner layer is hot melt adhesive.

In some embodiments, the outer layer polyolefin is a polyolefin-based halogen-free flame retardant material

In some embodiments, the material of the winding tube core is one of polyoxymethylene, polyethylene, polypropylene, ABS, polytetrafluoroethylene, carbon fiber, glass fiber, and nylon.

In some embodiments, the outer protrusion of the winding tube core is a protrusion of equal height with a shape including a triangle, a semicircle, a semiellipse, and a rectangle.

The present disclosure also provides a lithium battery separator winding process, comprising the following steps:

winding the separator on any of the above-mentioned lithium battery separator winding devices;

After the winding is completed, heat at 65℃～90℃;

After the heating is completed, place at 25℃～45℃ for 12h～36h for aging;

Roll up the aged diaphragm.

In some embodiments, the separator is a separator or a coated film after primary or secondary slitting.

The present disclosure also provides the use of the lithium battery separator winding device described above in the production of lithium ion battery separators.

The present disclosure also provides the use of the lithium battery separator winding device described above in the production of battery separators.

The present disclosure also provides the use of the lithium battery separator winding device described above in the production of lithium ion batteries.

The present disclosure also provides the use of the lithium battery separator winding device described above in the production of batteries.

Description of drawings

FIG. 1 is a schematic structural diagram of a diaphragm winding device according to an embodiment of the disclosure;

Component label description

1. Heat shrinkable sleeve;

2. Rewind the tube core.

Definition of Terms

As used herein, the term "collapsed edge" refers to the finished product of the isolation membrane, which is placed on the bracket horizontally and pulled out ≥5m horizontally, and there is a phenomenon of collapse on both sides;

As used herein, the term "aging and placing" means that after being deformed from high temperature processing, it is kept at a higher temperature or room temperature, waiting for the stress to be released, the size will further creep, and the product will be closer to the final form; "aging and placing" in this paper " is used to wait for the stress relief process in the diaphragm.

Detailed ways

Specific embodiments of the present disclosure will be described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, but not to limit the present disclosure.

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

Some embodiments of the present disclosure provide a lithium battery separator winding device, including a winding tube core and a heat shrinkable sleeve; the inner side of the winding tube core is annular and the outer side is convex; the heat shrinkable sleeve is sleeved on the shrinkage tube on the reel core.

In some embodiments, the heat shrinkable sleeve will be thermally shrunk at 65°C to 90°C, so that the distance from the outer layer to the center point of the annular shape inside the winding tube core (ie, the outer diameter of the entire winding device) is reduced 4～10mm. In some embodiments, the heat-shrinkable sleeve is heated at, eg, 65°C to 85°C, 70°C to 90°C, 70°C to 85°C, such as 65°C, 68°C, 70°C, 72°C, 74°C, 75°C, 78°C ℃, 80 ℃, 83 ℃, 85 ℃, 88 ℃, 90 ℃ will be thermally shrunk, so that the above distance is reduced by 5~10mm, 4~8mm or 5~8mm, such as 4mm, 4.5mm, 5mm, 6mm, 6.5mm , 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm.

In some embodiments, the heat shrink sleeve is a single wall heat shrink sleeve or a double wall heat shrink sleeve.

Specifically, the single-wall heat-shrinkable sleeve is preferably a PVC heat-shrinkable sleeve, an EVA heat-shrinkable sleeve, or a PET heat-shrinkable sleeve.

Specifically, the double-wall heat-shrinkable sleeve is preferably a double-wall heat-shrinkable sleeve containing an adhesive layer, which is produced by using a polyolefin-based halogen-free flame retardant material and a hot-melt adhesive double-layer co-extrusion process. The outer layer is polyolefin with the advantages of softness, low temperature shrinkage, anti-corrosion and wear resistance, and the inner layer is a hot melt adhesive with the advantages of low melting point, good fluidity, good adhesion and mechanical strain buffer.

Here, the reason why the heating temperature in the present disclosure is limited to 65°C to 90°C is that the heating temperature is within the range of the present disclosure, which can not only effectively shrink by heat, but also will not cause damage to the polyolefin separator due to excessive temperature. When the temperature is lower than 65°C, the above-mentioned materials cannot achieve thermal shrinkage because the temperature is too low. When the temperature is higher than 90°C, it will approach the shrinkage temperature of polyethylene, and there is a risk to the polyolefin separator.

In some embodiments, the material of the winding tube core is one of polyoxymethylene, polyethylene, polypropylene, ABS, polytetrafluoroethylene, carbon fiber, glass fiber, and nylon.

In some embodiments, the outer protrusions of the winding tube core are equal-height protrusions with shapes including triangles, semicircles, semiellipses, and rectangles.

It is believed that, without being bound by theory, there is no limitation on the shape of the contoured protrusions, as long as the outer diameter of the heat-shrinkable sleeve of the present disclosure is reduced by 4 mm to 10 mm, the heat-shrinkable sleeve is thermally shrunk and can fill the original contour. The gap between the raised core and the heat shrinkable sleeve is sufficient.

Some embodiments of the present disclosure provide a lithium battery separator winding process, including the following steps:

winding the separator on any of the above-mentioned lithium battery separator winding devices;

After the winding is completed, heat at 65℃～90℃;

After the heating is completed, place at 25℃～45℃ for 12h～36h for aging;

Roll up the aged diaphragm.

In some embodiments, in the above, the process of winding the aged separator is to perform secondary slitting and winding according to the required width and length specifications of the heated and time-limited lithium battery separator. It is believed, without being bound by theory, that the first rolls are generally wide and long rolls. After heating and aging, the internal stress is released, and then the secondary slitting is performed. The secondary slitting and winding is mainly based on the width and length of the target battery or coated product, and re-cutting is performed.

It is believed, without being bound by theory, that the separator is not limited and may be a separator or a coated film after primary or secondary slitting. There is no need to limit the heating temperature, because the heat shrinkable sleeve will shrink quickly in a short time and slowly shrink in a long time. For example, the heating time is 0.2h ~ 0.4h, such as 0.2h, 0.25h, 0.3h, 0.35h h, 0.4h, the outer diameter of the heat shrinkable sleeve can be reduced by 4mm to 10mm only through the overall coordination of temperature and time to meet the requirements of the present disclosure.

Some embodiments of the present disclosure also provide the use of the lithium battery separator winding device in the production of lithium ion battery separators.

Some embodiments of the present disclosure also provide the use of the lithium battery separator winding device in the production of battery separators.

Some embodiments of the present disclosure also provide the use of the lithium battery separator winding device in the production of lithium ion batteries.

Some embodiments of the present disclosure also provide the use of the lithium battery separator winding device in the production of batteries.

In the specific embodiment of the present disclosure, after the heat-shrinkable sleeve is thermally shrunk to reduce the outer diameter of the heat-shrinkable sleeve by 4 mm to 10 mm, a space is created between the heat-shrinkable sleeve and the diaphragm, and the release of the internal stress of the diaphragm will not be hindered, and the internal stress of the diaphragm will be released quickly, It will greatly alleviate the phenomenon of diaphragm extrusion or the deformation of diaphragm extrusion heat shrinkable sleeve. After heat shrinking treatment, place it for aging and wait for the internal stress of the diaphragm to be completely released. Finally, the collapse and deformation of the diaphragm product will be greatly alleviated, and the solution will be completely solved. There are bad phenomena such as violent tendons and folds.

The lithium battery separator winding device and process provided by the present disclosure are used to solve the problem of incomplete and unbalanced stress release in the separator caused by the pressure of the separator during the winding and rolling process of the lithium battery separator.

In the lithium battery separator winding device and process provided by the present disclosure, the material used for the heat shrinkable sleeve is in a glass state at room temperature, and becomes a high elastic state after heating. In the process of realizing the heat shrinking process, the heat shrinkable sleeve shrinks inwardly, and the outer diameter of the heat shrinkable sleeve decreases. In this way, the deformation and collapse of the diaphragm caused by the mutual extrusion of the diaphragm caused by shrinkage and the extrusion of the diaphragm core during the stress release process in the diaphragm can be greatly alleviated, and the uneven release of stress in the diaphragm will not lead to violent ribs and wrinkles. unpleasant sight.

The present disclosure will be described in detail below by way of examples.

In the following examples and comparative examples, performance parameters were determined as follows:

(1) Collapse deformation:

Hang the aged diaphragm on the support frame, guide the film through the double-mode film flatness measuring instrument DCM2-T2N2-L1600D-20190845, lay the diaphragm on the positioning line, keep the single side of the diaphragm coincident with the positioning line, and start the clamper , fix the diaphragm, measure the length is 6m, the weight standard is M=(30×width mm×length m)g, hang the counterweight, start the tester, read after 15s, select the maximum reading mm, and judge it as collapsed at the edge edge, otherwise it is judged to be deformed.

(2) folded ribs:

Judging by visual inspection and hand touch, the protrusions are violent tendons, and the scaly concavities and convexities are folds.

Example 1

As shown in Figure 1, a lithium battery separator winding device includes a winding tube core 2 (material is ABS) with regular triangular protrusions of equal height on the outer layer and a double-wall heat shrinkable rubber-containing layer wrapped in the outer layer. casing 1;

Wherein, the double-wall heat-shrinkable sleeve 1 is a double-wall heat-shrinkable sleeve containing an adhesive layer, the outer layer is polyolefin, and the inner layer is hot-melt adhesive.

When in use, step S1: the diaphragm is 9um, the outer diameter tube core of 170mm is used, the cutting tension is 1N at a time, the speed is 30m/min, and the double-wall heat shrinkable sleeve 1 containing the adhesive layer is wound at intervals, and the winding specification is ( 500mm×2000M);

S2: After the winding is completed, place it at 65°C for 0.4h heating, the heat shrinkable sleeve is thermally shrunk, and the hot melt adhesive with better inner fluidity fills the gap between the original core and the heat shrinkable sleeve, making the heat shrinkable sleeve The outer diameter of the tube is reduced by 4mm, while the outer diameter is kept smooth, and the internal stress of the diaphragm can be released quickly when there is no obstacle to the release of the internal stress of the diaphragm;

S3: After heat-shrinking treatment, place in 25℃ for 12h for aging and wait for the stress in the diaphragm to be released completely;

S4: Test the diaphragm wound on the double-wall heat-shrinkable sleeve 1 containing the adhesive layer after aging, and then perform secondary slitting after the test, and test again.

Example 2

As shown in Figure 1, a lithium battery separator winding device includes a winding tube core 2 (material is polytetrafluoroethylene) with regular triangular protrusions of equal height on the outer layer, and a double-layer double-layer rubber-containing layer wrapped in the outer layer. Wall heat shrinkable sleeve 1;

Wherein, the double-wall heat-shrinkable sleeve 1 is a double-wall heat-shrinkable sleeve containing an adhesive layer, the outer layer is polyolefin, and the inner layer is hot-melt adhesive.

When in use, step S1: diaphragm 9um, use 210mm outer diameter tube core, a slitting tension of 30N, speed 120m/min, and wound on the double-wall heat shrinkable sleeve 1 containing the adhesive layer, and the winding specification is ( 2000mm×2000M);

S2: After the winding is completed, place it at 90°C for 0.2h heating, the heat shrinkable sleeve is thermally shrunk, and the hot melt adhesive with better inner fluidity fills the gap between the original core and the heat shrinkable sleeve, making the heat shrinkable sleeve The outer diameter of the tube is reduced by 10mm, while the outer diameter is kept smooth, and the internal stress of the diaphragm can be released quickly when there is no obstacle to the release of the internal stress of the diaphragm;

S3: After heat shrinking treatment, place it at 45°C for 36 hours for aging, and wait for the stress in the diaphragm to be completely released;

S4: Test the diaphragm wound on the double-wall heat-shrinkable sleeve 1 containing the adhesive layer after aging, and then perform secondary slitting after the test, and test again.

Example 3

As shown in FIG. 1, a winding device for a lithium battery separator includes a winding tube core 2 (material is ABS) with regular triangular protrusions of equal height on the outer layer and a single-wall heat shrinkable sleeve 1 wrapped on the outer layer;

When using, step S1: the diaphragm is 9um, the outer diameter tube core is 170mm, the cutting tension is 1N at a time, the speed is 30m/min, and it is wound on the single-wall heat shrinkable sleeve 1. The winding specification is (500mm×2000M) ;

S2: After the winding is completed, place it at 65°C for 0.4h heating, the heat shrinkable sleeve is heated and shrunk, so that the outer diameter of the heat shrinkable sleeve is reduced by 4mm, and the internal stress of the diaphragm is released without hindrance.

S3: After heat-shrinking treatment, place in 25℃ for 12h for aging and wait for the stress in the diaphragm to be released completely;

S4: Test the diaphragm wound on the single-wall heat-shrinkable sleeve 1 after aging, perform secondary slitting after the test, and perform the test again.

Comparative Example 1

Select conventional 9um products, use 170mm outer diameter paper core, EPE buffer cotton hardness is 20HA, one slitting tension is 1N, speed 30m/min, winding specification is 500mm×2000M, at room temperature 25 ℃, aging for 12h, test , after the test, perform secondary slitting and test.

Comparative Example 2

Select conventional 9um products, use 210mm outer diameter paper core, EPE buffer cotton hardness is 80HA, one slitting tension is 30N, speed 120m/min, winding specification is 2000mm × 2000M, at 45 ℃, aging for 36h, test, After the test, the secondary slitting is carried out, and the test is carried out.

The performance tests of the diaphragms of the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 2 were performed according to the following methods, and the results were recorded in Table 1 below:

Table 1 Example and Comparative Example Finished Appearance Comparison

From the comparison of Examples 1 to 3 in the above table with Comparative Examples 1 to 2, it can be seen that the finished diaphragm products adopting the diaphragm winding device and process of the present disclosure completely solve the serious problems of diaphragm folds and stiff ribs, and greatly alleviate the problems of sagging and deformation. degree;

The longitudinal comparison between Example 1 and Example 2 shows that the higher the heating temperature, the greater the reduction in the outer diameter of the heat-shrinkable sleeve, and the longer the aging placement time, the finished diaphragm product has a better appearance;

In the longitudinal comparison between Example 1 and Example 3, it is found that the effect of using the double-wall heat shrinkable sleeve 1 containing the adhesive layer is better than that of using the single-wall heat shrinkable sleeve 1, because the double-wall heat shrinkable sleeve containing the adhesive layer is used. When the sleeve 1 is filled, the inner hot melt adhesive layer has higher fluidity than when the single-wall heat shrink sleeve 1 is filled. The double-wall heat shrink sleeve 1 makes the original winding core and the heat shrink sleeve. The interspace is filled more fully and completely, making the outer wall more round, and further promoting the release of the internal stress of the diaphragm.

The above contents related to common knowledge will not be described in detail, which can be understood by those skilled in the art.

The above descriptions are only some specific embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of the present disclosure. within the scope of protection. The technical scope of the present disclosure is not limited to the contents in the specification, and the technical scope must be determined according to the scope of the claims.

Industrial Applicability

In the lithium battery separator winding device and process provided by the present disclosure, the material used for the heat shrinkable sleeve is in a glass state at room temperature, and becomes a high elastic state after heating. In the process of realizing the heat shrinking process, the heat shrinkable sleeve shrinks inwardly, and the outer diameter of the heat shrinkable sleeve decreases. In this way, the deformation and collapse of the diaphragm caused by the mutual extrusion of the diaphragm caused by shrinkage and the extrusion of the diaphragm core during the stress release process in the diaphragm can be greatly alleviated, and the uneven release of stress in the diaphragm will not lead to violent ribs and wrinkles. It solves the problem of incomplete and unbalanced stress release in the diaphragm caused by the pressure of the diaphragm during the winding and rolling process of the lithium battery separator in the prior art, and has a wide range of application characteristics and excellent use value.

Claims (14)

1. A lithium battery diaphragm winding device is characterized in that: it comprises a winding tube core and a heat shrinkable sleeve; the inner side of the winding tube core is annular and the outer side is convex; the heat shrinkable sleeve is sleeved on the on the rewinding tube core.
2. The lithium battery separator winding device according to claim 1, wherein the heat-shrinkable sleeve is thermally shrunk at a temperature of 65°C to 90°C, so that the outer layer of the heat-shrinkable sleeve reaches the inner side of the winding tube core. The distance of the center point is reduced by 4 to 10mm.
3. The lithium battery separator winding device according to claim 2, wherein the heat-shrinkable sleeve is a single-wall heat-shrinkable sleeve or a double-wall heat-shrinkable sleeve.
4. The lithium battery separator winding device according to claim 3, wherein the single-wall heat-shrinkable sleeve comprises a PVC heat-shrinkable sleeve, an EVA heat-shrinkable sleeve, and a PET heat-shrinkable sleeve.
5. The lithium battery separator winding device according to claim 3, wherein the double-wall heat-shrinkable sleeve is a double-wall heat-shrinkable sleeve containing an adhesive layer, the outer layer is polyolefin, and the inner layer is hot-melt glue.
6. The lithium battery separator winding device according to claim 5, wherein:

   The outer layer polyolefin is a polyolefin halogen-free flame retardant material.
7. The lithium battery separator winding device according to any one of claims 1-6, wherein the material of the winding tube core is polyoxymethylene, polyethylene, polypropylene, ABS, PTFE, carbon fiber , one of glass fiber and nylon.
8. The lithium battery separator winding device according to any one of claims 1 to 6, wherein the outer protrusion of the winding tube core is a shape including a triangle, a semicircle, a semiellipse, and a rectangle of equal height. .
9. A lithium battery diaphragm winding process, characterized in that the process comprises the following steps:

   winding the separator on any lithium battery separator winding device according to any one of claims 1 to 8;

   After the winding is completed, heat at 65℃～90℃;

   After the heating is completed, place at 25℃～45℃ for 12h～36h for aging;

   Roll up the aged diaphragm.
10. The lithium battery separator winding process according to claim 9, wherein the separator is a separator or a coating film after primary or secondary slitting.
11. The use of any one of the lithium battery separator winding devices in claims 1 to 8 in the production of lithium ion battery separators.
12. The use of any one of the lithium battery separator winding devices in claims 1 to 8 in the production of battery separators.
13. The use of any one of the lithium battery separator winding devices in the production of lithium ion batteries according to any one of claims 1 to 8.
14. The use of any lithium battery separator winding device in the production of batteries according to any one of claims 1 to 8.

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