Lithium ion battery packaging device and lithium ion battery

Abstract

The utility model discloses a lithium ion battery packaging device and a lithium ion battery, the lithium ion battery packaging device comprises a sealing knife used for packaging the lithium ion battery, the sealing knife comprises an upper sealing knife and a lower sealing knife, a backstop piece is arranged on the pressing surface of the upper sealing knife and / or the lower sealing knife, and the backstop piece is arranged on the pressing surface of the upper sealing knife and / or the lower sealing knife. And the stop piece can stop the molten glue from flowing towards one side of the battery roll core. Through the arrangement of the stop piece, the stop piece can stop molten pp melt glue from flowing towards one side of a battery roll core, so that most of the pp melt glue flows towards the outer side of the battery, extruded glue is formed on the outer side of the battery, and redundant sealing edges are cut off according to process requirements after the battery is manufactured, so that the problem of glue extrusion in the battery is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery manufacturing, in particular to a lithium ion battery packaging device and a lithium ion battery. Background Art

[0002] During the production process of packaging the two sides of polymer lithium-ion batteries, when the upper and lower sealing knives squeeze the aluminum-plastic packaging film, the inner layer of the packaging film is heated and melted, and then naturally flows to both sides under the pressure of the upper and lower sealing heads. Therefore, in this process, about 1 / 2 of the PP melt melted by the sealing knife will flow to one side of the battery roll core. After the packaging is completed, the PP melt solidifies again, and the solidified PP glue forms squeezed glue. The shape of the squeezed glue is unpredictable, which will bring the following hidden dangers to the battery: 1) The squeezed glue affects the battery folding and affects the battery width; 2) There is a risk of squeezed glue piercing the diaphragm and pole piece; 3) After the battery folds, there is a risk of squeezed glue piercing the packaging film, affecting the reliability of the battery. How to solve the squeezed glue problem in the lithium-ion battery packaging process is still a technical problem that needs to be solved urgently. Utility Model Content

[0003] One of the purposes of the present invention is to provide a lithium-ion battery packaging device to solve the above technical problems.

[0004] In order to achieve the above purpose, the technical solution adopted by the utility model is: a lithium-ion battery packaging device, including a sealing knife for packaging lithium-ion batteries, the sealing knife including an upper sealing knife and a lower sealing knife, and a stopper is arranged on the pressing surface of the upper sealing knife and / or the lower sealing knife, and the stopper can prevent the melted glue from flowing to one side of the battery coil core.

[0005] Furthermore, the stopper is located at one end of the pressing surface close to the battery roll core, and the stopper can squeeze the packaging film.

[0006] Furthermore, the thickness of the stopper close to one end of the battery roll core is greater than the thickness of the stopper far from one end of the battery roll core.

[0007] Furthermore, the thickness of the stopper gradually decreases from close to the battery roll core to away from the battery roll core.

[0008] Furthermore, the surface of the stopper away from the sealing knife connected thereto is an inclined surface, which forms an angle with the horizontal plane. The horizontal plane here is a plane perpendicular to the sealing knife pressing direction. Usually, the sealing knife is pressed in the vertical direction, and the plane perpendicular to it is the horizontal plane.

[0009] Further, the angle ranges from 0 to 15°, excluding 0°. Exemplarily, the angle is 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°.

[0010] Furthermore, the stopper is integrally connected to the sealing knife, and the stopper and the sealing knife are made of the same material. When the sealing knife is heated during the pressing process, the stopper will also be heated.

[0011] On the other hand, the utility model provides a lithium-ion battery packaging process, comprising the following steps: placing a battery roll core in a film cavity, covering the upper and lower sides of the battery roll core with a packaging film, and using the lithium-ion battery packaging device as described above to press the packaging film at the edge of the battery roll core.

[0012] Further, the packaging temperature of the lithium-ion battery is 150-190° C. Exemplarily, the packaging temperature of the lithium-ion battery is 150° C., 160° C., 170° C., 180° C., 190° C.

[0013] Further, the packaging pressure of the lithium-ion battery is 0.2-0.4 MPa. For example, the packaging pressure of the lithium-ion battery is 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, and 0.4 MPa.

[0014] The utility model also provides a lithium ion battery, which is obtained by packaging using the lithium ion battery packaging device as described above.

[0015] The beneficial effects of the utility model are:

[0016] 1) By setting the stopper, the stopper can block the melted PP melt from flowing to one side of the battery core, so that most of the PP melt flows to the outside of the battery, forming glue squeeze on the outside of the battery. After the battery is manufactured, the excess edge sealing is cut off according to the process requirements, thereby solving the problem of glue squeeze inside the battery.

[0017] 2) Through the wedge-shaped structure of the stopper, the top corner near the battery core side contacts the packaging film first, and is subjected to force and heat. The area of ​​this position is small and will not cause a large amount of PP melt. As the sealing knife moves, the upper and lower sealing knives gradually contact closely and finally contact completely. In this process, the channel for the PP melt to flow outward is always maintained, that is, the one-way flow is always maintained. At the same time, because the pressure on the inside is always greater than that on the outside, the inward flow of the hot-melt PP melt is effectively restricted, and finally a special side edge (battery sealing edge) with a thin inside and a thick outside is formed, which is conducive to the folding of polymer lithium-ion batteries. Compared with conventional processes, it has obvious advantages in controlling the battery width and can reduce the battery width by about 1mm.

[0018] 3) By limiting the angle to 0 to 15 degrees, the problem of glue extrusion on the battery cell is solved and the hidden dangers caused by glue extrusion are eliminated. It is also beneficial to folding the edges and reducing the battery width. It will not affect the battery packaging effect. The battery is in a high temperature and high humidity environment for 96 hours, and there is no blackening, corrosion, cracking, or leakage at the battery seal, which meets the standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and the description thereof are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the traditional packaging process;

[0022] Figure 2 This is a schematic diagram of the packaging process of the utility model;

[0023] Figure 3 The figures are comparison diagrams of batteries packaged by a conventional packaging device and a battery packaged by the packaging device of the present invention, wherein a is a schematic diagram of a battery packaged by a conventional packaging device, and b is a schematic diagram of a battery packaged by the packaging device of the present invention;

[0024] Figure 4 This is a front view of a sealing knife according to an embodiment of the utility model;

[0025] Figure 5 This is a front view of a sealing knife according to another embodiment of the utility model;

[0026] Figure 6 This is a front view of a sealing knife according to another embodiment of the utility model;

[0027] Figure 7 This is a three-dimensional diagram of a sealing knife according to another embodiment of the present utility model.

[0028] Among them: 1. Sealing knife; 11. Upper sealing knife; 12. Lower sealing knife; 13. Pressing surface; 2. Battery roll core; 3. Packaging film; 31. PP melt glue; 311. Extruded glue; 4. Stopper; 41. Inclined surface; 42. Side surface; 43. Top angle; 44. Angle; 5. Folded edge. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0030] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to indicate the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the attached claims are approximate values, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and appropriately change these approximate values. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0031] See attached Figure 2 As shown, a lithium-ion battery packaging device includes a sealing knife 1 for packaging lithium-ion batteries, wherein the sealing knife 1 includes an upper sealing knife 11 and a lower sealing knife 12. During the packaging process, the upper sealing knife 11 and the lower sealing knife 12 approach each other, and the packaging film 3 between the upper sealing knife 11 and the lower sealing knife 12 is pressed to package the lithium-ion battery.

[0032] The packaging film 3 is a three-layer structure, including a nylon layer, an aluminum layer and a pp layer connected in sequence. The nylon layer is located on the outermost side of the battery roll core 2 to prevent corrosion and scratches on the battery from the external environment; the aluminum layer is used to block moisture and form a skeleton layer with a fixed tensile structure; the pp layer is arranged close to the battery cell, and the battery is sealed by heating and fusing the pp layer.

[0033] The applicant found that, see attached Figure 1As shown, when the conventional packaging device packages the two sides of the battery roll core 2, since the pressing surfaces 13 of the upper and lower sealing knives 1 are relatively parallel surfaces, the temperature of the sealing knife 1 is heated to about 150°C to 190°C. When the upper sealing knife 11 and the lower sealing knife 12 squeeze the aluminum-plastic packaging film 3, the PP layer of the inner layer of the packaging film 3 is melted by heat, and then naturally flows to both sides under the pressure of the upper sealing knife 11 and the lower sealing knife 12. Therefore, in this process, about 1 / 2 of the PP melt 31 melted by the sealing knife 1 will flow to one side of the battery roll core 2. After the packaging is completed, the PP melt 31 solidifies again, and the solidified PP glue forms squeezed glue 311. The shape of squeezed glue 311 is unpredictable. Squeezed glue 311 may pierce the diaphragm and the pole piece. Squeezed glue 311 may also cause the packaging film 3 to be pierced after the battery is folded, affecting the reliability of the battery. Therefore, the safety hazards of squeezed glue 311 to the battery are difficult to predict. At the same time, since the solidified glue is concentrated at the R corner of the battery, it affects the battery folding 5 and increases the battery width.

[0034] In view of the above problems, the existing solutions are to reduce the packaging temperature and pressure as much as possible, and reserve a certain distance from the core to ensure that the packaging glue 311 will not damage the core; the folding edge is far away from the glue 311 to ensure that the glue 311 will not damage the packaging film 3. Then observe the glue 311 through destructive sampling inspection, adjust the parameters in time, prevent glue 311, and control and prevent glue extrusion through the above process aspects. See the attached Figure 3 As shown in a, since the cured glue set 311 is at the R corner of the battery, the reserved distance affects the battery fold 5 and increases the battery width. Therefore, the above solution is not only cumbersome to operate, but also affects the battery width.

[0035] See attached Figure 2 , 4 As shown in Figure 7, the present application provides a stopper 4 on the pressing surface 13 of the sealing blade 1. The pressing surface 13 is a surface of the sealing blade 1 close to the packaging film 3, that is, when the sealing blade 1 is used as the upper sealing blade 11, the pressing surface 13 is the lower side surface of the upper sealing blade 11, and when the sealing blade 1 is used as the lower sealing blade 12, the pressing surface 13 is the upper side surface of the lower sealing blade 12. The stopper 4 is located at one end of the pressing surface 13 close to the battery roll core 2, and the thickness of the stopper 4 close to the end of the battery roll core 2 is greater than the thickness of the stopper 4 away from the end of the battery roll core 2. Since the stopper 4 is arranged on the pressing surface 13, during the pressing process of the sealing knife 1, since the stopper 4 is arranged close to one end of the battery core 2, the stopper 4 can block the melted pp melt 31 from flowing to the side of the battery core 2, so that most of the pp melt 31 flows to the outside of the battery, forming squeezed glue 311 on the outside of the battery. After the battery is manufactured, the excess sealing edge 5 is cut off according to the process requirements, thereby solving the problem of squeezed glue 311 inside the battery.

[0036] In some embodiments, the stopper 4 can be set on the pressing surface 13 of the upper sealing knife 11, or on the pressing surface 13 of the lower sealing knife 12, or on both the pressing surfaces 13 of the upper sealing knife 11 and the lower sealing knife 12 to block the melted PP glue.

[0037] In some embodiments, the stopper 4 is integrally connected to the sealing knife 1 , and the sealing knife 1 and the stopper 4 are made of the same material. During the packaging and pressing process of the packaging film 3 , the stopper 4 first contacts the packaging film 3 , and the packaging film 3 is heated and pressed first.

[0038] See attached Figure 4 As shown, the stopper 4 is a strip-shaped structure, which is arranged on the pressing surface 13 of the sealing knife 1 and is arranged at one end close to the battery roll core 2. During the pressing process of the sealing knife 1 on the packaging film 3, due to the setting of the stopper 4, the pp melt 31 located on the outside of the stopper 4 cannot flow to the inside of the battery stopper 4 due to the obstruction of the stopper 4, and thus no squeezed glue 311 will be formed on the inside of the battery component.

[0039] In some embodiments, the thickness of the stopper 4 gradually decreases from close to the battery roll core 2 to away from the battery roll core 2. Figure 5 As described above, the stopper 4 is in the shape of a staircase, and the PP melt 31 flows toward the outside of the battery along the trapezoidal surface.

[0040] See attached Figure 6 and attached Figure 7 As shown, in some other embodiments, the stopper 4 is a wedge-shaped structure, that is, the surface close to the packaging film 3 is a slope 41 structure, and the slope 41 and the horizontal plane form an angle 44, named α. The slope 41 and the side surface 42 of the stopper 4 close to the battery cell form a vertex angle 43, named β, α+β=90°, and the range of the angle 44 is 0<α≤15°.

[0041] During the pressing process of the sealing knife 1, since the stopper 4 has a certain angle, the top corner 43 on the side close to the battery core 2 preferentially contacts the packaging film 3 and is subjected to force and heat. The area of ​​this position is relatively small and will not cause a large amount of PP melt 31. As the sealing knife 1 moves, the upper sealing knife 11 and the lower sealing knife 12 gradually come into close contact and finally come into complete contact. In this process, the channel for the PP melt 31 to flow outward is always maintained, that is, unidirectional flow is always maintained. At the same time, since the inner pressure is always greater than the outer pressure, the inward flow of the hot-melt PP melt 31 is effectively restricted, and finally a special side edge (battery sealing edge) that is thin inside and thick outside is formed, which effectively solves the problem of PP glue squeezing 311 of polymer lithium-ion batteries.

[0042] See attached Figure 3As shown, the battery edge sealing surface is thin inside and thick outside, which is very conducive to the folding of polymer lithium-ion batteries. Compared with conventional processes, it has obvious advantages in controlling the battery width and can reduce the battery width by about 1mm. This patent is especially important for controlling the width of narrow batteries.

[0043] Experimental studies have shown that when the angle α is greater than 15°, the battery is fully charged and stored in a high temperature and high humidity environment for 96 hours. The appearance of the battery is observed and it is found that some corners of the bottom of the battery are blackened. The reason may be that the inclined surface 41 has a large inclination angle, which causes the pressing force of the inclined surface 41 to become smaller, resulting in poor battery packaging effect, oxidation reaction, and a black oxide layer on the battery surface. Therefore, in the utility model, the angle α is ≤15°.

[0044] The utility model also provides a lithium-ion battery packaging process, including the following steps: placing the battery core 2 in the film cavity, the upper and lower sides of the battery core 2 are covered with a packaging film 3, the PP layer of the packaging film 3 is arranged close to the battery core 2, and the above-mentioned sealing knife 1 is used to heat and press the packaging film 3 located at the edge of the battery core 2, the packaging temperature is 150-190°C, and the packaging pressure is 0.2-0.4MPa. During the pressing process, the PP layer melts, and since the stopper 4 is preferentially contacted on the side close to the core, it is subjected to force and heat, and the area of ​​this position is small and will not cause a large amount of PP melt. As the head moves, the upper and lower heads gradually contact closely, and finally contact completely. In this process, the channel for the PP glue to flow outward is always maintained, that is, the unidirectional flow is always maintained. At the same time, since the inner layer pressure is always greater than the outer layer, the hot melt PP glue is effectively restricted from flowing inward; finally, a special side edge with a thin inner side and a thick outer side is formed to complete the packaging of the battery cell.

[0045] Example

[0046] The following examples describe the disclosure of the present invention in more detail, and these examples are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations may be made within the scope of the disclosure of the present invention. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0047] Example 1

[0048] The battery core 2 is placed in the film cavity, and the upper and lower sides of the battery core are covered with the packaging film 3. The PP layer of the packaging film 3 is arranged close to the battery core 2. The sealing knife 1 is used to heat and press the packaging film 3 on both sides of the battery core 2. The packaging temperature is 190°C, the packaging pressure is 0.3MPa, the pressing time is 3.5 minutes, and the angle α is 10°

[0049] Embodiment 2-10

[0050] The battery packaging process of Examples 2-10 is the same, except that the packaging pressure, packaging temperature and angle α parameters are adjusted. The specific details are shown in Table 1:

[0051] Table 1 Specific packaging parameters of Examples 1-10

[0052]

[0053]

[0054] Comparative Examples 1-10

[0055] The battery packaging processes of Comparative Examples 1-10 are the same as the packaging processes of battery cells of Examples 1-10, and the packaging temperatures and packaging pressures correspond one to one, that is, the parameters of Comparative Example 1 correspond to those of Example 1, the parameters of Comparative Example 2 correspond to those of Example 2, and so on, the parameters of Comparative Example 10 correspond to those of Example 10. The main difference is that the pressing surface of the sealing knife in Comparative Examples 1-10 is a planar structure, that is, the angles are all 0°.

[0056] Comparative Examples 11-20

[0057] The battery packaging processes of Examples 11-20 are the same as the packaging processes of the battery cells of Examples 1-10, and the packaging temperatures and packaging pressures correspond one to one, that is, the parameters of Example 11 correspond to those of Example 1, the parameters of Example 12 correspond to those of Example 2, and so on, the parameters of Example 20 correspond to those of Example 10. The main difference is that the angles between the inclined surface and the horizontal plane of the stopper are both 20°.

[0058] Experimental Example 1:

[0059] The tensile force test of the seal of Examples 1-10 and Comparative Examples 1-10 was conducted by cutting a 5 mm wide strip from the side of the battery cell and testing the separation tensile force of the seal with a tensile tester. Specific data are shown in Table 2:

[0060] Table 2: Seal tensile force data

[0061]

[0062]

[0063] In this field, the tensile force at the 5 mm wide battery seal needs to be greater than 15 N. From the data in Table 2, it can be seen that the packaging tensile force of Examples 1-10 is greater than 21 N, which is much greater than 15 N and meets industry standards.

[0064] From the comparison data of Example 1-10 and Comparative Example 1-10, it can be seen that there is no obvious change in the packaging tension with the stopper (Example 1-10) and without the stopper (Comparative Example 1-10), that is, the setting of the stopper does not reduce the tension value at the seal and does not affect the packaging effect.

[0065] Experimental Example 2:

[0066] The battery of model 603048-900mAh was prepared by the process of Examples 1-10 and Comparative Examples 11-20. After the battery was fully charged, it was placed in a high temperature and high humidity environment for 96 hours, with the ambient temperature being 60° and the humidity being 90% HR, and the appearance of the battery was observed. The battery cells that met the standards had no blackening, corrosion, cracking, or leakage at the battery seal. The observed phenomena are shown in Table 3:

[0067] Table 3 Observation phenomenon

[0068] Serial number Observation phenomenon Serial number Observation phenomenon Example 1 Comply with standards Comparative Example 11 Comply with standards Example 2 Comply with standards Comparative Example 12 Comply with standards Example 3 Comply with standards Comparative Example 13 The bottom corner of the battery is black Example 4 Comply with standards Comparative Example 14 Slight corrosion on the bottom corner of the battery Example 5 Comply with standards Comparative Example 15 Comply with standards Example 6 Comply with standards Comparative Example 16 The bottom corner of the battery is black Example 7 Comply with standards Comparative Example 17 Comply with standards Example 8 Comply with standards Comparative Example 18 The bottom corner of the battery is black Example 9 Comply with standards Comparative Example 19 The bottom corner of the battery is black Example 10 Comply with standards Comparative Example 20 The bottom corner of the battery is black

[0069] From the observations recorded in Table 3, it can be seen that when the utility model is used for packaging, the angle α≤15° will not affect the battery reliability. When the angle is greater than 15°, it will have a certain impact on the battery reliability. Some batteries have black bottom corners or slight corrosion at the bottom corners. Therefore, limiting the angle to 0-15 degrees not only solves the problem of battery cell glue extrusion and eliminates the hidden dangers caused by glue extrusion, but also facilitates folding and reducing the battery width. It will not affect the battery packaging effect. The battery has been in a high temperature and high humidity environment for 96 hours, and there is no blackening, corrosion, cracking, or leakage at the battery seal, which meets the standard.

[0070] The above implementation modes are only for illustrating the technical concept and features of the utility model, and their purpose is to allow people familiar with this technology to understand the content of the utility model and implement it. It cannot be used to limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A lithium-ion battery packaging device, comprising a sealing knife (1) for packaging lithium-ion batteries, wherein the sealing knife (1) comprises an upper sealing knife (11) and a lower sealing knife (12), characterized in that: A stopper (4) is provided on the pressing surface (13) of the upper sealing knife (11) and / or the lower sealing knife (12), and the stopper (4) can prevent the melted adhesive from flowing toward one side of the battery winding core (2).

2. A lithium-ion battery packaging device according to claim 1, characterized in that: The thickness of the stopper (4) at one end close to the battery winding core (2) is greater than the thickness at one end away from the battery winding core (2).

3. A lithium-ion battery packaging device according to claim 1, characterized in that: The thickness of the stopper (4) gradually decreases from close to the battery winding core (2) to away from the battery winding core (2).

4. A lithium-ion battery packaging device according to claim 1, characterized in that: The surface of the stopper (4) away from the sealing knife (1) connected thereto is an inclined surface (41) and forms an angle (44) with the horizontal plane.

5. A lithium-ion battery packaging device according to claim 4, characterized in that: The angle (44) ranges from 0 to 15°, excluding 0°.

6. A lithium-ion battery packaging device according to claim 1, characterized in that: The stopper (4) and the sealing knife (1) are integrally connected.

7. A lithium ion battery, characterized in that: The method is obtained by packaging the lithium ion battery using the lithium ion battery packaging device according to any one of claims 1 to 6.

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