阅读说明：本技术 一种挤出厚度均匀的锂电池三层共挤隔膜用模头 (Die head for three-layer co-extrusion diaphragm of lithium battery with uniform extrusion thickness ) 是由 李汪洋 胡伟 吴磊 张德顺 何祥燕 杨建军 张建安 陈曼 刘久逸 吴庆云 吴明元 于 2021-08-09 设计创作，主要内容包括：本发明公开了一种挤出厚度均匀的锂电池三层共挤隔膜用模头,包括模头本体,所述模头本体的内部至上而下设有第一料仓、第二料仓和第三料仓,所述第一料仓、第二料仓和第三料仓的右侧分别设有与出料口连通的上出料部、中出料部和下出料部,所述上出料部和下出料部分别设置于中出料部的两侧,所述第一料仓、第二料仓和第三料仓之间和两侧的模头本体上设有第一电热丝,所述上出料部、中出料部和下出料部的上、下边沿均匀水平结构,所述第一料仓和第三料仓通过安装于模头本体外侧的支管连接有进料管,所述第二料仓的左侧设有进料口,本发明克服了现有技术的不足,避免了直接挤出过程中压力变化导致的三层复合料各层厚度变化大的问题。(The invention discloses a die head for a lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness, which comprises a die head body, wherein a first bin, a second bin and a third bin are arranged inside the die head body from top to bottom, the right sides of the first bin, the second bin and the third bin are respectively provided with an upper discharging part, a middle discharging part and a lower discharging part which are communicated with a discharging port, the upper discharging part and the lower discharging part are respectively arranged at two sides of the middle discharging part, first heating wires are arranged on the die head body among the first bin, the second bin and the third bin and at two sides, the upper edge and the lower edge of the upper discharging part, the middle discharging part and the lower discharging part are in a uniform horizontal structure, the first bin and the third bin are connected with a feeding pipe through branch pipes arranged at the outer side of the die head body, and a feeding port is arranged at the left side of the second bin, the problem of large thickness change of each layer of the three-layer composite material caused by pressure change in the direct extrusion process is avoided.)

1. The utility model provides an extrude even lithium cell three-layer of thickness and crowd die head for diaphragm altogether, includes the die head body, be equipped with discharge gate, its characterized in that on the right flank of die head body: the utility model discloses a die head, including die head body, first feed bin, second feed bin and third feed bin, the inside of die head body is equipped with first feed bin, second feed bin and third feed bin to the top down, the right side of first feed bin, second feed bin and third feed bin is equipped with last ejection of compact portion, well ejection of compact portion and the ejection of compact portion down that communicates with the discharge gate respectively, go up ejection of compact portion and down the ejection of compact portion and set up respectively in the both sides of well ejection of compact portion, be equipped with first heating wire between first feed bin, second feed bin and the third feed bin and on the die head body of both sides, go up the even horizontal structure of upper and lower border of ejection of compact portion, well ejection of compact portion and ejection of compact portion down, first feed bin and third feed bin have the inlet pipe through installing the leg joint in the die head body outside, the left side of second feed bin is equipped with the feed inlet.

2. The die head for the lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness as claimed in claim 1, wherein: and second heating wires are also arranged in the die head matrixes on the upper side and the lower side of the discharge hole, and the temperature of the first heating wire is 20-30 ℃ higher than that of the second heating wire.

3. The die head for the lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness as claimed in claim 1, wherein: an arc-shaped part is arranged between the second storage bin and the middle discharging part, and the upper surface and the lower surface of the arc-shaped part are of arc-shaped structures which are symmetrically arranged.

4. The die head for the lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness as claimed in claim 1, wherein: the top end of the die head body on the upper side and the lower side of the middle discharging part is also provided with a triangular edge.

5. The die head for the lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness as claimed in claim 4, wherein: the thickness of the die head body among the upper discharging part, the middle discharging part and the lower discharging part at the triangular edge is 0.5-1.0 mm.

6. The die head for the lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness as claimed in claim 1, wherein: still be connected through constant voltage mechanism between first feed bin and second feed bin, second feed bin and the third feed bin, constant voltage mechanism is used for keeping the pressure balance between first feed bin and second feed bin, second feed bin and the third feed bin.

7. The die head for the lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness as claimed in claim 6, wherein: constant voltage mechanism includes the constant voltage pipe, the both ends of constant voltage pipe are equipped with keeps off the ring, keep off the intraductal movable mounting of constant voltage between the ring and have the piston, the both ends of constant voltage pipe are respectively through intercommunication portion and first feed bin, second feed bin or third feed bin intercommunication.

Technical Field

The invention relates to the technical field of extrusion dies, and particularly belongs to a die head for a lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness.

Background

In recent years, the lithium ion battery technology has been developed rapidly, and the performance of the lithium ion battery is determined by the separator as one of the core materials in the battery, so that the separator material and the preparation technology are urgently needed to be studied deeply. At present, the commercialized lithium battery separator is mainly a polyolefin-baked separator, and the preparation process is transiting from a dry method to a wet method, but separators of different material systems and different preparation processes have been developed in recent years.

The diaphragm is used as a key material of the lithium battery, plays a role in electronic isolation in the battery, prevents direct contact of a positive electrode and a negative electrode, allows lithium ions in electrolyte to freely pass through, and plays a vital role in guaranteeing safe operation of the battery. In special cases, such as accidents, punctures, battery abuse, etc., the separator is partially damaged to cause direct contact of the positive and negative electrodes, thereby causing severe battery reaction to cause ignition and explosion of the battery.

Therefore, in order to improve the safety of the lithium ion battery and ensure the safe and stable operation of the battery, the coating on-line considers that the diaphragm must meet the following conditions of (1) chemical stability: no reaction with electrolyte and electrode materials; (2) wettability: the electrolyte is easy to wet and does not extend or shrink; (3) high temperature resistance and high fusing isolation; (4) the mechanical strength is good, namely the tensile strength is good, so that the strength and the width are unchanged during automatic winding; (5) higher porosity to meet the ionic conductivity requirements.

Currently, commercially available lithium battery separators in the market are mainly microporous polyolefin separators mainly made of Polyethylene (PE) and polypropylene (PP), and such separators are widely used in lithium battery separators due to their advantages of low cost, good mechanical properties, excellent chemical stability and electrochemical stability. The practical application of the diaphragm also comprises a single-layer PP or PE diaphragm, a double-layer PE/PP composite diaphragm, a double-layer PP/PP composite diaphragm and a three-layer PP/PE/PP composite diaphragm. The three-layer PP/PE/PP composite diaphragm is widely used for battery diaphragms due to excellent mechanical property and corrosion resistance, while the existing three-layer co-extrusion die head adopts a direct extrusion compounding mode, and in the process of conveying molten materials, the thickness change of each layer of the extruded three-layer composite material is large due to the nonuniformity of feeding pressure, and the uniformity of products is poor.

Disclosure of Invention

The invention aims to provide a die head for a lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness, which solves the problems of large thickness change of each layer of a three-layer composite material extruded by the die head and poor product uniformity.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a die head for a lithium battery three-layer co-extrusion diaphragm with uniform extrusion thickness comprises a die head body, wherein a discharge hole is formed in the right side surface of the die head body, a first bin, a second bin and a third bin are arranged in the die head body from top to bottom, an upper discharging part, a middle discharging part and a lower discharging part which are communicated with the discharging port are respectively arranged on the right sides of the first bin, the second bin and the third bin, the upper discharging part and the lower discharging part are respectively arranged at two sides of the middle discharging part, first heating wires are arranged among the first bin, the second bin and the third bin and on the die head bodies at two sides, go up the even horizontal structure of upper and lower border of ejection of compact portion, well ejection of compact portion and lower ejection of compact portion, first feed bin and third feed bin have the inlet pipe through installing the branch connection in the die head body outside, the left side of second feed bin is equipped with the feed inlet.

Preferably, the die head base bodies on the upper side and the lower side of the discharge port are also internally provided with second heating wires, and the temperature of the first heating wire is 20-30 ℃ higher than that of the second heating wire.

Preferably, be equipped with arc portion between second feed bin and the well ejection of compact portion, the upper and lower surface of arc portion is the arc structure of symmetry setting.

Preferably, triangular edges are further arranged at the top ends of the die head bodies on the upper side and the lower side of the middle discharging part.

Preferably, the thickness of the die body between the upper discharging part, the middle discharging part and the lower discharging part at the triangular edge is 0.5-1.0 mm.

Preferably, the first bin and the second bin, and the second bin and the third bin are further connected through a constant pressure mechanism, and the constant pressure mechanism is used for keeping pressure balance between the first bin and the second bin, and between the second bin and the third bin.

Preferably, constant voltage mechanism includes the constant voltage pipe, the both ends of constant voltage pipe are equipped with and keep off the ring, keep off the intraductal movable mounting of constant voltage between the ring and have the piston, the both ends of constant voltage pipe are respectively through intercommunication portion and first feed bin, second feed bin or third feed bin intercommunication.

Compared with the prior art, the invention has the following implementation effects:

1. according to the invention, the first bin, the second bin and the third bin are arranged, so that molten materials entering the die head are buffered, the direct extrusion compounding of the traditional basic process is avoided, the molten materials pass through the buffering of the first bin, the second bin and the third bin, so that the molten materials in the first bin, the second bin and the third bin can uniformly flow out from the upper discharging part, the middle discharging part and the lower discharging part, the pressures of the upper discharging part, the middle discharging part and the lower discharging part are uniform, and the problem of large thickness change of each layer of the three-layer compound material caused by pressure change in the direct extrusion process is avoided.

2. According to the invention, the constant pressure mechanisms are arranged among the first bin, the second bin and the third bin, so that the pressure in the extrusion process of the first bin, the second bin and the third bin is equal, and the problem that the thickness of the extrusion layer is thinned due to the fact that the extrusion layer with high pressure extrudes the extrusion layer with low pressure in each layer extruded from the upper discharge part, the middle discharge part and the lower discharge part due to sudden change of the feeding pressure is avoided.

3. The invention aims to further raise the temperature of each extruded layer, so that each layer expands in the discharge port, the composite strength among the extruded layers is improved, the triangular edges have a guiding function, and pores among the extruded layers are avoided.

Drawings

FIG. 1 is a front view of the present invention;

FIG. 2 is a top view of the present invention;

FIG. 3 is a cross-sectional view A-A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2;

fig. 5 is an enlarged view at C in fig. 4.

Description of reference numerals: 1. a die head body; 11. a feed inlet; 12. a discharge port; 13. a feed pipe; 14. a branch pipe; 2. a first storage bin; 3. a second storage bin; 31. a lower discharge part; 4. a third storage bin; 41. an arc-shaped portion; 42. a middle discharge part; 5. a first heating wire; 6. a second heating wire; 7. triangular edges; 8. a constant pressure tube; 81. a baffle ring; 82. a piston; 9. a communicating portion.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation to be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1

The lithium battery three-layer co-extrusion diaphragm die head with uniform extrusion thickness as shown in fig. 1-4 comprises a die head body 1, a discharge hole 12 is arranged on the right side surface of the die head body 1, a first bin 2, a second bin 3 and a third bin 4 are arranged inside the die head body 1 from top to bottom, an upper discharge part, a middle discharge part 42 and a lower discharge part 31 which are communicated with the discharge hole 12 are respectively arranged on the right sides of the first bin 2, the second bin 3 and the third bin 4, the upper discharge part and the lower discharge part 31 are respectively arranged on two sides of the middle discharge part 42, the first bin 2, the second bin 3 and the third bin 4 buffer molten materials entering the die head, so that the direct extrusion compounding of the traditional basic process is avoided, the molten materials pass through the buffering of the first bin 2, the second bin 3 and the third bin 4, and the molten materials in the first bin 2, the second bin 3 and the third bin 4 can be uniformly extruded from the upper discharge part, the lower discharge part and the lower discharge part, Well discharge portion 42 and lower discharge portion 31 flow out, and go up discharge portion, well discharge portion 42 and the pressure of ejection of compact down even, avoided the problem that each layer thickness of three-layer composite that direct extrusion in-process pressure variation leads to changes greatly.

Be equipped with first heating wire 5 between first feed bin 2, second feed bin 3 and the third feed bin 4 and on the die head body 1 of both sides, be equipped with second heating wire 6 in the die head base member of both sides about discharge gate 12, and the temperature of first heating wire 5 is higher 30 ℃ than the temperature of second heating wire 6, and specific temperature can be selected at 20-30 ℃ within range as required, and first feed bin 2 and third feed bin 4 are connected with inlet pipe 13 through installing branch pipe 14 in the die head body 1 outside, and the left side of second feed bin 3 is equipped with feed inlet 11. The first heating wire 5 can avoid the solidification of the molten material in the die head body 1, and the second heating wire 6 has a higher temperature than the first heating wire 5, so that the temperature of each extruded layer is further raised, each layer is expanded in the discharge port 12, and the composite strength between each extruded layer is improved.

The upper and lower edges of the upper discharging part, the middle discharging part 42 and the lower discharging part 31 are uniformly in a horizontal structure, so that the surface of the extruded layer flowing out of each discharging part is smooth and flat. Be equipped with arc portion 41 between second feed bin 3 and well discharge portion 42, the upper and lower surface of arc portion 41 is the arc structure that the symmetry set up, and the arc structure extrudees the melting material that second feed bin 3 flowed, and the middle structure of extruding the layer that makes well discharge portion 42 flow is even. The top ends of the die head bodies 1 on the upper side and the lower side of the middle discharging part 42 are also provided with triangular ribs 7, the thickness of the die head bodies 1 among the upper discharging part, the middle discharging part 42 and the lower discharging part 31 at the triangular ribs 7 is 0.6mm, the specific thickness can be selected within the range of 0.5-1.0mm according to needs, and the triangular ribs 7 play a guiding role to avoid pores among extrusion layers.

Example 2

As a further technical solution of the present invention, as shown in fig. 4-5, the first silo 2 and the second silo 3, and the second silo 3 and the third silo 4 are further connected by a constant pressure mechanism, and the constant pressure mechanism is used for maintaining pressure balance between the first silo 2 and the second silo 3, and between the second silo 3 and the third silo 4. Constant voltage mechanism includes constant voltage pipe 8, and the both ends of constant voltage pipe 8 are equipped with and keep off ring 81, keep off movable mounting in the constant voltage pipe 8 between the ring 81 and have piston 82, and the both ends of constant voltage pipe 8 are passed through the intercommunication portion 9 respectively and are linked together with first feed bin 2, second feed bin 3 or third feed bin 4. Constant voltage mechanism makes first feed bin 2, second feed bin 3 and third feed bin 4 at the in-process pressure of extruding equalling, has avoided the sudden change of feeding pressure, causes from last ejection of compact portion, well ejection of compact portion 42 and the lower ejection of compact portion 31 each layer of extruding, and the layer extrusion is extruded to the extrusion layer that pressure is little to pressure that pressure is big, leads to the problem of its thickness attenuation.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.