Hot melting knife, hot melting device and welding method

Abstract

The invention belongs to the technical field of hot melting and welding, and discloses a hot melting cutter, a hot melting device and a welding method.The hot melting cutter comprises an installation part and a hot melting part which are integrally formed, the installation part is configured to be installed on a machine tool, a heating hole allowing a heating piece to penetrate is formed in the installation part, and the heating hole extends in the horizontal direction; therefore, the heating wire can heat the mounting part and the hot melting part. The hot melting part is provided with a plurality of convex points in a protruding manner, the convex points can pierce the first PMMA diaphragm layer and reach the base membrane position of the second PMMA diaphragm layer, and meanwhile, heat is conducted to melt the base membrane layers of the two PMMA diaphragm layers, so that the two PMMA diaphragm layers are welded, and the stability of the diaphragm assembly is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of hot melt welding, and in particular to a hot melt knife, a hot melt device and a welding method. Background Art

[0002] The diaphragm assembly is the inner component of the lithium battery. Its main function is to separate the positive and negative electrodes of the battery to prevent short circuits caused by contact between the two electrodes. The performance of the diaphragm assembly determines the interface structure and internal resistance of the battery, which directly affects the battery's capacity, cycle and safety performance.

[0003] In the prior art, the diaphragm assembly in some lithium batteries is just two layers of PMMA diaphragms stacked together, which cannot ensure the stability of the two layers of PMMA diaphragms. In addition, the double-sided adhesive layer of the PMMA diaphragm will block the temperature of the hot melt knife from melting the internal PE (diaphragm base film) layer, resulting in the two layers of PMMA diaphragms not being able to be welded. Summary of the invention

[0004] The object of the present invention is to provide a hot melt knife, a hot melt device and a welding method, wherein the hot melt knife can realize the welding of two layers of PMMA diaphragms and ensure the stability of the diaphragm assembly.

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

[0006] In a first aspect, a hot melt knife is provided for welding two layers of PMMA membranes, comprising an integrally formed mounting portion and a hot melt portion, wherein the mounting portion is configured to be mounted on a machine tool, and a heating hole is provided on the mounting portion to allow a heating element to pass through, and the heating hole extends in a horizontal direction; a plurality of protrusions are provided on the hot melt portion, and the protrusions can pierce through the first layer of the PMMA membrane and reach the base film position of the second layer of the PMMA membrane.

[0007] As an optional solution for the hot melt knife, a plurality of connection holes are opened on the mounting portion, a plurality of connection members are passed through the machine tool, and the plurality of connection members are passed through the plurality of connection holes in a one-to-one correspondence.

[0008] As an optional solution for the hot melt knife, a avoidance surface is provided on one side of the hot melt portion.

[0009] As an optional solution for the hot melt knife, the mounting portion and the hot melt portion are both made of brass material.

[0010] In a second aspect, a hot melt device is provided, comprising:

[0011] A cold cutter, which is arranged on the machine tool, is used to cut the PMMA diaphragm to be welded;

[0012] The hot melt knife is arranged on the machine tool and spaced apart on one side of the cold cutter, and is used to weld two layers of the PMMA membrane;

[0013] A heating element is inserted into the heating hole and is used for heating the hot melt knife.

[0014] As an optional solution of the hot melt device, a plurality of cutting teeth are arranged on the side of the cold cutting knife facing the PMMA membrane, and a tip is arranged on the side of each cutting tooth close to the PMMA membrane.

[0015] As an optional solution of the hot melt device, the heating element is spiral-shaped.

[0016] As an optional solution of the hot melt device, a plurality of heating elements are provided, and each of the heating elements is penetrated into the heating hole.

[0017] As an optional solution of the hot melt device, the hot melt device further comprises a driving mechanism, the driving mechanism is arranged on the machine tool, and the cold cutting knife and the hot melt knife are both connected to the output end of the driving mechanism.

[0018] In a third aspect, a hot melt method is also provided, which is applied to the hot melt device described above, and comprises the following steps:

[0019] S1: Use a cold cutter to cut the PMMA diaphragm to be welded to form two PMMA diaphragms;

[0020] S2: Stack two PMMA diaphragms together and use a hot melt knife to complete the welding of the two layers of PMMA diaphragms.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a hot melt knife, a hot melt device and a welding method, wherein the hot melt knife comprises an integrally formed mounting portion and a hot melt portion, wherein the mounting portion is configured to be mounted on a machine tool, and a heating hole is provided on the mounting portion to allow a heating element to pass through, and the heating hole extends in a horizontal direction so that a heating wire can heat the mounting portion and the hot melt portion. The hot melt portion is provided with a plurality of protrusions, which can pierce through a first layer of PMMA diaphragm and reach the base film position of a second layer of PMMA diaphragm, and at the same time conduct heat to fuse the base film layers of the two layers of PMMA diaphragms, so as to weld the two layers of PMMA diaphragms, thereby ensuring the stability of the diaphragm assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a hot melt knife provided in a specific embodiment of the present invention;

[0024] Figure 2 It is a structural schematic diagram of another orientation of the hot melt knife provided in an embodiment of the specific implementation of the present invention.

[0025] In the figure:

[0026] 1. Installation part; 11. Heating hole; 12. Connection hole;

[0027] 2. Hot-melt portion; 21. Protruding point; 22. Avoidance surface. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0029] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0031] In the description of this embodiment, the terms "upper", "lower", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0032] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0033] This embodiment provides a hot melt knife for welding two layers of PMMA membranes. The material composition of the PMMA membrane is a PMMA coating layer, a base film layer, a ceramic coating layer and a PMMA coating layer in sequence. Hot melting two layers of PMMA membranes mainly uses a hot melt knife to weld the base film area in the PMMA membrane so that the base film area is melted. The base film is a PE film or a PP film. The melting point of the PE film is 135°C and the melting point of the PP film is 160°C. The outer PMMA membrane coating layer will block the temperature of the hot melt knife from melting the inner base film. If the temperature of the hot melt knife is continuously increased, the PMMA membrane will easily break. The melting point of the ceramic coating is above 2000°C, and the temperature of the hot melt knife is difficult to reach, so it cannot be used as a hot melt surface.

[0034] like Figure 1 to Figure 2 As shown, the hot melt knife includes an integrally formed mounting portion 1 and a hot melt portion 2. The mounting portion 1 is configured to be mounted on a machine tool. A heating hole 11 is provided on the mounting portion 1 to allow the heating element to pass through. The heating hole 11 extends in a horizontal direction so that the heating wire can heat the mounting portion 1 and the hot melt portion 2. The hot melt portion 2 is provided with a plurality of protrusions 21, which can pierce the first layer of PMMA diaphragm and reach the base film position of the second layer of PMMA diaphragm, and at the same time conduct heat to melt the base film layers of the two layers of PMMA diaphragms, so as to weld the two layers of PMMA diaphragms, thereby ensuring the stability of the diaphragm assembly.

[0035] Optionally, the mounting portion 1 is provided with a plurality of connection holes 12, and the machine tool is provided with a plurality of connection members, which are correspondingly inserted into the plurality of connection holes 12 to mount the hot melt knife on the machine tool. Specifically, the connection members are bolts commonly used in the art, and correspondingly, the connection holes 12 are threaded holes, which are simple and convenient to operate, and the materials are easy to obtain, and have good economic efficiency.

[0036] Optionally, a side of the hot melt section 2 is provided with an avoidance surface 22 to prevent the hot melt knife from interfering with other structures on the machine tool during the hot melt operation. Specifically, in this embodiment, the avoidance surface 22 is composed of an inclined surface and a step surface; in other embodiments, the specific form of the avoidance surface 22 can be set as required, as long as the hot melt knife can be prevented from interfering with other structures on the machine tool, and no specific limitation is made here.

[0037] Optionally, the mounting portion 1 and the hot-melt portion 2 are both made of brass material, which has good thermal conductivity and corrosion resistance.

[0038] In addition, this embodiment also provides a hot melt device, including a cold cutter, the hot melt knife and a heating element, wherein the cold cutter is arranged on a machine tool and is used to cut the PMMA membrane to be welded, the hot melt knife is also arranged on the machine tool and is arranged at a distance on one side of the cold cutter and is used to weld two layers of PMMA membranes, and the heating element is inserted into the heating hole 11 and is used to heat the hot melt knife. The hot melt device has all the beneficial effects of the hot melt knife and will not be described in detail here.

[0039] Specifically, the heating element is a commonly used heating wire in the art, which heats the hot melt knife based on the thermal effect of the electric current to weld the base film layer. The heating element and the cold cutter are both existing structures in the art, and their specific structures and working principles refer to the existing technology and are not described here.

[0040] Optionally, a plurality of cutting teeth are provided on the side of the cold cutting knife facing the PMMA membrane, and a tip is provided on the side of each cutting tooth close to the PMMA membrane, so as to facilitate rapid cutting of the PMMA membrane and improve working efficiency.

[0041] Optionally, the heating element is spiral-shaped to effectively extend the length of the heating element within the limited space of the heating hole 11 and increase the heating rate of the hot melt knife.

[0042] Optionally, a plurality of heating elements are provided, each of which is disposed in the heating hole 11 to further improve the heating rate of the hot melt knife. Specifically, the number of heating elements can be set according to actual needs.

[0043] Optionally, the hot melt device further comprises a driving mechanism, which is arranged on the machine tool, and the cold cutter and the hot melt knife are both connected to the output end of the driving mechanism. Driven by the driving mechanism, the cold cutter and the hot melt knife can be close to or away from the PMMA diaphragm to complete the cutting or hot melting of the PMMA diaphragm. Specifically, the cold cutter and the hot melt knife are respectively provided with a driving mechanism to realize the independent movement of the cold cutter and the hot melt knife. Exemplarily, the driving mechanism is a cylinder commonly used in the art, and its specific structure and principle refer to the prior art, which will not be repeated here.

[0044] In addition, this embodiment also provides a welding method, which is applied to the above-mentioned hot-melt device and includes the following steps:

[0045] S1: Use a cold cutter to cut the PMMA diaphragm to be welded to form two PMMA diaphragms.

[0046] In the above steps, specifically in this embodiment, under the drive of the corresponding driving mechanism, the cold cutting knife moves close to the PMMA membrane to cut the PMMA membrane to form two PMMA membranes.

[0047] S2: Stack two PMMA diaphragms together and use a hot melt knife to complete the welding of the two layers of PMMA diaphragms.

[0048] In the above steps, specifically in this embodiment, two PMMA membranes are stacked together, and then driven by a corresponding driving mechanism, the hot melt knife moves in a direction close to the PMMA membrane, and the multiple protrusions 21 on the hot melt portion 2 all pass through the first PMMA membrane and reach the base film layer of the second PMMA membrane. At the same time, the heating wire heats the hot melt portion 2 to weld the base film layers of the two PMMA membranes, thereby completing the welding of the two PMMA membranes.

[0049] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A hot melt knife for welding two layers of PMMA membranes, characterized in that: The invention comprises an integrally formed mounting portion (1) and a hot-melt portion (2), wherein the mounting portion (1) is configured to be mounted on a machine tool, and a heating hole (11) is provided on the mounting portion (1) to allow a heating element to pass through, and the heating hole (11) extends in a horizontal direction; a plurality of protrusions (21) are provided on the hot-melt portion (2), and the protrusions (21) can pierce through the first layer of the PMMA membrane and reach the base membrane position of the second layer of the PMMA membrane.

2. The hot melt knife according to claim 1, characterized in that: The mounting portion (1) is provided with a plurality of connection holes (12), the machine tool is provided with a plurality of connection members, and the plurality of connection members are correspondingly inserted into the plurality of connection holes (12).

3. The hot melt knife according to claim 1, characterized in that: A relief surface (22) is provided on one side of the hot-melt portion (2).

4. The hot melt knife according to claim 1, characterized in that: The mounting portion (1) and the hot-melt portion (2) are both made of brass material.

5. A hot melt device, characterized in that: include: A cold cutter, which is arranged on the machine tool, is used to cut the PMMA diaphragm to be welded; The hot melt knife described in any one of claims 1 to 4 is arranged on the machine tool and is spaced apart on one side of the cold cutter, and is used to weld two layers of the PMMA diaphragm; A heating element is inserted into the heating hole (11) and is used for heating the hot melt knife.

6. The hot melt device according to claim 5, characterized in that: A plurality of cutting teeth are arranged on the side of the cold cutting knife facing the PMMA diaphragm, and a tip is arranged on the side of each cutting tooth close to the PMMA diaphragm.

7. The hot melt device according to claim 5, characterized in that: The heating element is in a spiral shape.

8. The hot melt device according to claim 5, characterized in that: A plurality of heating elements are provided, and each heating element is disposed in the heating hole (11).

9. The hot melt device according to claim 5, characterized in that: The hot melt device also includes a driving mechanism, which is arranged on the machine tool, and the cold cutting knife and the hot melt knife are both connected to the output end of the driving mechanism.

10. A welding method, characterized in that: The hot melt device used in any one of claims 5 to 9 comprises the following steps: S1: Use a cold cutter to cut the PMMA diaphragm to be welded to form two PMMA diaphragms; S2: Stack two PMMA diaphragms together and use a hot melt knife to complete the welding of the two layers of PMMA diaphragms.

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