阅读说明：本技术 一种正负极耳粘结剂及其制备方法、极片的制作方法 (Positive and negative electrode lug binder, preparation method thereof and manufacturing method of pole piece ) 是由 吕新坡 于 2020-10-23 设计创作，主要内容包括：本发明公开了一种正负极耳粘结剂及其制备方法、极片的制作方法,首先,通过正极耳粘结剂制备方法制备正极耳粘结剂；其次,通过负极耳粘结剂制备方法制备负极耳粘结剂；再次,将正极极耳与正极片的第一重叠粘结部位涂覆一层如上述制得的正极耳粘结剂,将涂覆有所述正极耳粘结剂的正极极耳粘结在正极片的第一重叠粘结部位上；最后,将负极极耳与负极片的第二重叠粘结部位涂覆一层如上述制得的负极耳粘结剂,将涂覆有所述负极耳粘结剂的负极极耳粘结在负极片的第二重叠粘结部位上,本发明在涂布时无需预留极耳焊接位置,通过粘结的方式使极耳与极片集流体相连接,充分利用内部空间,提高能量密度,提高生产效率,降低安全隐患。(The invention discloses a positive and negative electrode tab binder and a preparation method thereof, and a manufacturing method of a pole piece, wherein the positive electrode tab binder is prepared by a positive electrode tab binder preparation method; secondly, preparing a negative electrode tab binder by a negative electrode tab binder preparation method; coating a layer of the anode tab binding agent prepared as above on the first overlapped binding part of the anode tab and the anode plate, and binding the anode tab coated with the anode tab binding agent on the first overlapped binding part of the anode plate; and finally, coating a layer of the cathode lug binder prepared as above on the second overlapped bonding part of the cathode lug and the cathode sheet, and bonding the cathode lug coated with the cathode lug binder on the second overlapped bonding part of the cathode sheet.)

1. The preparation method of the positive and negative electrode tab binder is characterized by comprising the following steps:

s1, preparing a positive tab binder, namely mixing conductive carbon black, polyvinylidene fluoride and N-methyl pyrrolidone according to the weight ratio of 1: 9: 90, under the condition that the humidity is less than or equal to 30 percent, controlling the temperature between 30 and 40 ℃, stirring for 1.5 to 2.5 hours by using stirring equipment with the linear speed of 5 to 8m/min to form uniformly dispersed slurry, and standing for 3.5 to 4.5 hours after stirring to form the anode tab binder;

the preparation method of the negative electrode tab binder comprises the following steps:

s2, preparing a negative electrode tab binder, mixing conductive carbon black, sodium carboxymethyl cellulose and water according to the weight ratio of 1: 5: 95, controlling the temperature between 30 and 40 ℃, stirring for 1.5 to 2.5 hours by using stirring equipment with the linear velocity of 5 to 8m/min to form uniformly dispersed slurry, adding 48 percent styrene-butadiene rubber aqueous solution again, and stirring for 0.5 to 0.75 hour by using stirring equipment with the linear velocity of 3 to 5m/min to form the cathode lug binder.

2. The positive and negative tab binders are characterized in that the positive tab binders are prepared by the positive tab binder preparation method in claim 1, and the negative tab binders are prepared by the negative tab binder preparation method in claim 1.

3. A manufacturing method of positive and negative pole pieces is characterized by comprising the following steps:

s10, coating the first overlapped bonding part (3) of the positive tab (1) and the positive plate (2) with a layer of positive tab bonding agent according to claim 2;

s20, bonding the positive electrode tab (1) coated with the positive electrode tab bonding agent on the first overlapped bonding part (3) of the positive electrode sheet (2);

s30, coating the second overlapped bonding part (6) of the negative electrode tab (4) and the negative electrode sheet (5) with a layer of the negative electrode tab binder according to claim 2;

and S40, bonding the negative electrode tab (4) coated with the negative electrode tab bonding agent on the second overlapped bonding part (6) of the negative electrode sheet (5).

4. The method for manufacturing the positive and negative electrode plates according to claim 3, wherein the positive electrode tab (1) and the positive electrode plate (2) are bonded and then pressed for 0.2-0.4S by using a pressure of 0.1-0.3MPa, and the negative electrode tab (4) and the negative electrode plate (5) are bonded and then pressed for 0.2-0.4S by using a pressure of 0.1-0.3 MPa.

5. The method for manufacturing the positive and negative pole pieces according to claim 4, wherein the positive pole piece (2) is attached with adhesive paper (7) with the thickness of 0.15-0.3mm at the position corresponding to the wound negative pole tab (4).

6. The method for manufacturing the positive and negative pole pieces as claimed in claim 5, wherein the positive pole piece (2) bonded with the positive pole tab (1) is placed in an oven to be baked for 4-6h, the temperature of the oven is controlled to be 80-90 ℃, the vacuum degree in the oven is less than or equal to-0.08 Mpa, the negative pole piece (5) bonded with the negative pole tab (4) is placed in the oven to be baked for 4-6h, the temperature of the oven is controlled to be 80-90 ℃, and the vacuum degree in the oven is less than or equal to-0.08 Mpa.

Technical Field

The invention relates to the technical field of lithium ion battery manufacturing, in particular to a positive and negative electrode lug binder, a preparation method thereof and a manufacturing method of a pole piece.

Background

Since the nineties of the twentieth century, the research and production of lithium ion batteries have made great progress, and the application of lithium ion batteries in various fields is becoming more and more extensive. Polymer lithium ion batteries are favored in more and more fields due to high safety and customizability of shapes, and with the explosive growth of industries such as wireless earphones and electronic cigarettes, the miniature polymer battery cells are in a situation of being short of supply, and with the rapid growth of miniature consumer electronics represented by wireless earphones, higher requirements are put forward on the energy density of lithium batteries.

The lithium battery is composed of positive and negative pole pieces, a diaphragm, electrolyte and a shell, wherein the positive and negative pole pieces are one of core components, positive and negative pole slurry is respectively coated on positive and negative current collectors, as shown in figure 1, in the process of producing the positive pole piece 2 of the existing soft package battery, a welding mode is mainly adopted at present, namely, a positive pole tab 1 and the positive pole piece 2 are stacked together, and are combined together under the action of laser or ultrasonic wave to form a structure with a welding spot 9, but the problem of welding penetration or poor welding is easy to occur, meanwhile, in the coating process, a positive pole tab 10 needs to be reserved without coating, the coating is used for welding the positive pole tab 1 in the subsequent process, the width of the reserved positive pole tab 10 is larger than that of the positive pole tab 1 for the stability of the welding process, a certain space is wasted, the improvement of energy density is limited, and the same way, the negative electrode sheet 5 also has the above-described problems.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a positive and negative electrode tab bonding agent, a preparation method thereof and a manufacturing method of a pole piece.

In order to achieve the purpose, the invention provides a preparation method of a positive and negative electrode tab binder, which comprises the following steps:

s1, preparing a positive tab binder, namely mixing conductive carbon black, polyvinylidene fluoride and N-methyl pyrrolidone according to the weight ratio of 1: 9: 90, under the condition that the humidity is less than or equal to 30 percent, controlling the temperature between 30 and 40 ℃, stirring for 1.5 to 2.5 hours by using stirring equipment with the linear speed of 5 to 8m/min to form uniformly dispersed slurry, and standing for 3.5 to 4.5 hours after stirring to form the anode tab binder;

the preparation method of the negative electrode tab binder comprises the following steps:

s2, preparing a negative electrode tab binder, mixing conductive carbon black, sodium carboxymethyl cellulose and water according to the weight ratio of 1: 5: 95, controlling the temperature between 30 and 40 ℃, stirring for 1.5 to 2.5 hours by using stirring equipment with the linear velocity of 5 to 8m/min to form uniformly dispersed slurry, adding 48 percent styrene-butadiene rubber aqueous solution again, and stirring for 0.5 to 0.75 hour by using stirring equipment with the linear velocity of 3 to 5m/min to form the cathode lug binder.

The invention also provides a positive and negative electrode tab binder, which is prepared by the preparation method of the positive electrode tab binder, and the negative electrode tab binder is prepared by the preparation method of the negative electrode tab binder.

The invention also provides a manufacturing method of the positive and negative pole pieces, which comprises the following steps:

s10, coating a layer of the positive electrode tab binder prepared as above on the first overlapped bonding part of the positive electrode tab and the positive electrode sheet;

s20, bonding the positive electrode tab coated with the positive electrode tab bonding agent on the first overlapped bonding part of the positive electrode sheet;

s30, coating a layer of the negative electrode tab binder prepared as above on the second overlapped bonding part of the negative electrode tab and the negative electrode sheet;

and S40, bonding the negative electrode tab coated with the negative electrode tab bonding agent on the second overlapped bonding part of the negative electrode sheet.

Preferably, the positive electrode tab and the positive electrode sheet are pressed for 0.2 to 0.4S by using the pressure of 0.1 to 0.3MPa after being bonded, and the negative electrode tab and the negative electrode sheet are pressed for 0.2 to 0.4S by using the pressure of 0.1 to 0.3MPa after being bonded.

Preferably, the positive electrode sheet is attached with adhesive paper with the thickness of 0.15-0.3mm at the position corresponding to the wound negative electrode tab.

Preferably, the positive plate bonded with the positive electrode tab is placed into an oven to be baked for 4-6h, the temperature of the oven is controlled between 80 ℃ and 90 ℃, the vacuum degree in the oven is less than or equal to-0.08 Mpa, the negative plate bonded with the negative electrode tab is placed into the oven to be baked for 4-6h, the temperature of the oven is controlled between 80 ℃ and 90 ℃, and the vacuum degree in the oven is less than or equal to-0.08 Mpa.

Compared with the prior art, the invention has the beneficial effects that:

1. in the coating process, the positive and negative electrode slurry can be coated on all the positive and negative electrode current collectors respectively to manufacture the positive plate and the negative plate, the reserved electrode lug positions for welding with the electrode lugs are not required to be reserved, the electrode lugs are connected with the electrode plate current collectors in a bonding mode, the internal space is fully utilized, and the energy density is improved.

2. The positive electrode tab binder and the negative electrode tab binder prepared by the invention have excellent conductivity and binding property, are firmly connected, and avoid the phenomenon of welding through or infirm welding between the electrode tabs and the pole pieces caused by a welding method in the process of manufacturing the soft package battery, thereby improving the production efficiency, reducing the potential safety hazard when the battery is used, and being particularly suitable for the process of manufacturing the customized or small-batch-produced lithium ion soft package battery.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic diagram illustrating a conventional welding of a positive tab and a positive plate;

FIG. 2 is a schematic structural diagram of a positive plate of the manufacturing method of the positive and negative plates provided by the invention;

FIG. 3 is a schematic structural diagram of a negative electrode plate of the manufacturing method of the positive and negative electrode plates provided by the invention;

FIG. 4 is a schematic flow chart of steps of a method for manufacturing positive and negative electrode plates according to the present invention. The figure includes:

1-positive pole lug, 2-positive pole piece, 3-first overlapped bonding part, 4-negative pole lug, 5-negative pole piece, 6-second overlapped bonding part, 7-gummed paper, 9-welding point and 10-reserved positive pole lug.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are one embodiment of the present invention, and not all embodiments of the present invention. All other embodiments obtained by a person skilled in the art based on the embodiments of the present invention without any creative work belong to the protection scope of the present invention.

Example one

The embodiment of the invention provides a preparation method of a positive and negative electrode lug binder, which comprises the following steps:

step S1, preparing a positive tab binder, namely mixing conductive carbon black, polyvinylidene fluoride (PVDF) and N-methylpyrrolidone (NMP) according to the weight ratio of 1: 9: 90, under the condition that the humidity is less than or equal to 30 percent, controlling the temperature between 30 and 40 ℃, stirring for 1.5 to 2.5 hours by using stirring equipment with the linear speed of 5 to 8m/min to form uniformly dispersed slurry, and standing for 3.5 to 4.5 hours after stirring to form the anode tab binder;

the preparation method of the negative electrode tab binder comprises the following steps:

step S2, preparing a negative electrode tab binder by mixing conductive carbon black, sodium carboxymethylcellulose and water in a ratio of 1: 5: 95, controlling the temperature between 30 and 40 ℃, stirring for 1.5 to 2.5 hours by using stirring equipment with the linear velocity of 5 to 8m/min to form uniformly dispersed slurry, adding 48 percent styrene-butadiene rubber aqueous solution again, and stirring for 0.5 to 0.75 hour by using stirring equipment with the linear velocity of 3 to 5m/min to form the cathode lug binder.

Example two

The second embodiment of the invention provides a positive and negative electrode tab binder, the positive electrode tab binder is prepared by the preparation method of the positive electrode tab binder in the first embodiment, and the negative electrode tab binder is prepared by the preparation method of the negative electrode tab binder in the first embodiment.

EXAMPLE III

In the third embodiment, as shown in fig. 2, the positive electrode tab 1 can be directly bonded to the positive electrode sheet 2 by coating the first overlap bonding portion 3 of the positive electrode sheet 2 with the positive electrode tab bonding agent described above.

In the third embodiment, as shown in fig. 3, the negative electrode tab 4 can be directly bonded to the negative electrode sheet 5 by coating a layer of the negative electrode tab bonding agent on the second overlapped bonding portion 6 of the negative electrode sheet 5.

Referring to fig. 2 to 4, a third embodiment of the present invention provides a method for manufacturing positive and negative electrode plates, where the method includes the following steps:

step S10 of coating the first overlap-bonded portion 3 of the positive electrode tab 1 and the positive electrode sheet 2 with a layer of the positive electrode tab bonding agent according to claim 2;

step S20 of bonding the positive electrode tab 1 coated with the positive electrode tab bonding agent to the first overlap bonding portion 3 of the positive electrode sheet 2;

step S30, coating the second overlapped bonding part 6 of the negative electrode tab 4 and the negative electrode sheet 5 with a layer of the negative electrode tab bonding agent according to claim 2;

in step S40, the negative electrode tab 4 coated with the negative electrode tab binder is bonded to the second overlap bonding site 6 of the negative electrode sheet 5.

Because the bonding connection mode is adopted, after a layer of positive pole lug bonding agent is coated at one end of the positive pole lug 1, the positive pole lug is bonded on the positive pole piece 2, the bonding agent is solidified to firmly combine the positive pole lug 1 with the current collector, the seamless joint and the conductive action of the positive pole piece 2 and the positive pole lug 1 are realized, the operation is simple and rapid, the phenomenon that the positive pole lug 1 and the positive pole piece 2 are welded or welded firmly in the process of manufacturing the positive pole piece of the soft package battery by a welding method is avoided, the production efficiency can be improved, the potential safety hazard when the battery is used is reduced, the method is particularly suitable for the process of manufacturing the lithium ion soft package battery which is customized or produced in small batch, the relative positions of the positive pole piece 2 and the positive pole lug 1 which are connected by using the positive pole lug bonding agent are more accurate and orderly, the quality of the battery is improved, and the negative pole piece 2 is also obtained by the, also has the advantages mentioned above and will not be described in detail herein.

After the positive pole tab 1 and the positive pole piece 2 are bonded, the pressure of 0.1-0.3MPa is used for pressing 0.2-0.4S, and after the negative pole tab 4 and the negative pole piece 5 are bonded, the pressure of 0.1-0.3MPa is used for pressing 0.2-0.4S.

And the positive plate 2 is attached with adhesive paper 7 with the thickness of 0.15-0.3mm at the position corresponding to the wound negative pole tab 4.

And placing the positive plate 2 bonded with the positive electrode tab 1 into an oven to be baked for 4-6h, controlling the temperature of the oven to be 80-90 ℃, controlling the vacuum degree in the oven to be less than or equal to-0.08 Mpa, placing the negative plate 5 bonded with the negative electrode tab 4 into the oven to be baked for 4-6h, controlling the temperature of the oven to be 80-90 ℃, and controlling the vacuum degree in the oven to be less than or equal to-0.08 Mpa.

And after the positive plate 2 and the negative plate 5 are baked by an oven, carrying out subsequent processes according to the existing manufacturing method of the soft package battery, and carrying out the steps of winding, packaging, injecting liquid, forming and the like on the positive plate 2 and the negative plate 5.

In conclusion, the beneficial effects of the invention are as follows:

in the coating process, the positive and negative electrode slurry can be coated on all the positive and negative electrode current collectors respectively to manufacture the positive plate 2 and the negative plate 5, a reserved electrode lug position for welding with the electrode lug is not required to be reserved, the electrode lug is connected with the electrode plate current collector in a bonding mode, the internal space is fully utilized, and the energy density is improved; the positive electrode tab binder and the negative electrode tab binder prepared by the invention have excellent conductivity and binding property, are firmly connected, and avoid the phenomenon of welding through or infirm welding between the electrode tabs and the pole pieces caused by a welding method in the process of manufacturing the soft package battery, thereby improving the production efficiency, reducing the potential safety hazard when the battery is used, and being particularly suitable for the process of manufacturing the customized or small-batch-produced lithium ion soft package battery.