CN111628226B

CN111628226B - Lamination process and lamination device

Info

Publication number: CN111628226B
Application number: CN202010484226.9A
Authority: CN
Inventors: 王学飞; 孙晓辉
Original assignee: Svolt Energy Technology Co Ltd
Current assignee: Svolt Energy Technology Co Ltd
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2022-06-21
Anticipated expiration: 2040-06-01
Also published as: CN111628226A

Abstract

The application discloses a lamination process method and a lamination device, wherein the lamination process method at least comprises the following steps: s1: coating the diaphragm and drying the coated diaphragm; s3: attaching a plurality of prepared first pole pieces on a diaphragm, wherein the first pole pieces are arranged on the diaphragm at intervals; s5: the starting diaphragm is folded upwards to be coated on the first pole piece, and the first second pole piece is folded on the starting diaphragm to form a pole piece group; s7: turning over the pole piece group to be folded on the diaphragm, continuously superposing a new second pole piece on the pole piece group, and continuing the process until the number of the pole pieces in the pole piece group meets the requirement; the first pole piece is a negative pole piece, and the second pole piece is a positive pole piece; or the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece. The lamination process method improves the bonding performance between the diaphragm and the first pole piece, and ensures the safety of the battery; and meanwhile, the production efficiency of the laminated battery cell is greatly improved.

Description

Lamination process method and lamination device

Technical Field

The application relates to the technical field of batteries, in particular to a lamination process method and a lamination device.

Background

At present, the preparation method of the battery core of the lithium ion battery mainly comprises two types of winding and stacking, and the lamination type process is to alternately stack a positive plate, a diaphragm and a negative plate together. Many enterprises can carry out hot pressing to the pole piece group before electric core encapsulation, make the inside and outside temperature rise of pole piece group soften the PVDF glue granule on the diaphragm coating, fully bond between diaphragm and the pole piece to reach the purpose of stereotyping. However, due to insufficient heating temperature, partial PVDF adhesive particles are cured, so that a good bonding effect cannot be achieved for some thicker pole piece groups, the split layers of the diaphragm and the pole pieces are caused, and the safety of the battery is affected.

Summary of the invention

The present application is directed to solving at least one of the problems in the prior art.

Therefore, an object of the present application is to provide a lamination process method, which can enhance the adhesion between the separator and the first pole piece, and improve the safety of the battery;

another objective of the present application is to provide a lamination device, which can perform cell preparation by using the lamination process method described above.

In order to solve the above problems, one aspect of the present application provides a lamination process method, including at least the following steps:

s1: coating the diaphragm and drying the coated diaphragm;

s3: attaching a plurality of prepared first pole pieces on a diaphragm, wherein the first pole pieces are arranged on the diaphragm at intervals;

s5: the starting diaphragm is folded upwards to be coated on the first pole piece, and the first second pole piece is folded on the starting diaphragm to form a pole piece group;

s7: turning over the pole piece group to be folded on the diaphragm, continuously superposing a new second pole piece on the pole piece group, and continuing the process until the number of the pole pieces in the pole piece group meets the requirement; the first pole piece is a negative pole piece, and the second pole piece is a positive pole piece; or the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

The lamination process method improves the bonding performance between the diaphragm and the first pole piece, the method can achieve the thermal compounding effect of the first pole piece and the diaphragm, the diaphragm cannot shrink due to high temperature, and the safety of the battery is ensured; meanwhile, all the first pole pieces are thermally compounded with the diaphragm in advance, and only the second pole pieces need to be superposed in the process, so that the production efficiency of the laminated battery cell is greatly improved.

Further, in step S1, incomplete drying is applied to the separator.

Further, in step S1, the drying degree of the membrane after drying the membrane is 85% -95%.

Further, in step S1, the drying temperature is 30-70 ℃.

Further, still include: and step S4, clamping the first pole piece and the diaphragm and drying the first pole piece and the diaphragm again.

Further, the drying temperature for drying the first pole piece and the diaphragm again is 40-90 ℃, and the clamping force between the first pole piece and the diaphragm is 1kgf/cm²-10kgf/cm²。

Further, the length of the diaphragm between two adjacent first pole pieces is L1, the length of the second pole piece is L2, and the L1 and the L2 satisfy: l1 is more than or equal to 2L 2.

Further, the L1 satisfies: 320mm ≦ L2 ≦ 1200mm, the L2 satisfying: l2 is more than or equal to 160mm and less than or equal to 600 mm.

Another aspect of the present application provides a lamination device, comprising: unwinding the diaphragm; the diaphragm coating piece is arranged at the downstream of the diaphragm unwinding and is suitable for coating the diaphragm; a first oven disposed downstream of the separator coating member and adapted to dry the separator; the pole piece pasting piece is arranged at the downstream of the first drying oven and is suitable for pasting the negative pole piece or the positive pole piece on the diaphragm; and the second oven is arranged at the downstream of the first oven and is suitable for drying the negative plate or the diaphragm of the negative plate.

Further, still include: and the pressing piece is suitable for pressing the negative plate or the positive plate and the diaphragm.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic view of a lamination device according to an embodiment of the present application;

FIG. 2 is a flow chart of a lamination process according to an embodiment of the present application;

FIG. 3 is a schematic view of a first pole piece thermally composited with a separator in accordance with an embodiment of the present application;

FIG. 4 is a first schematic flow chart of a lamination process according to an embodiment of the present disclosure;

FIG. 5 is a schematic flow chart II of a lamination process method according to an embodiment of the application;

FIG. 6 is a third schematic flow chart of a lamination process method according to an embodiment of the present application;

FIG. 7 is a fourth schematic flow chart of a lamination process method according to an embodiment of the present application;

FIG. 8 is a schematic flow chart of a lamination process method according to an embodiment of the present application;

FIG. 9 is a sixth schematic flow chart of a lamination process according to an embodiment of the present application;

FIG. 10 is a seventh schematic flow chart of a lamination process method according to an embodiment of the present application;

FIG. 11 is a schematic flow chart eight of a lamination process method according to an embodiment of the present application;

FIG. 12 is a nine schematic flow chart of a lamination process according to an embodiment of the present application;

fig. 13 is a schematic view of a laminated pole piece stack made by a lamination process method according to an embodiment of the present application.

Reference numerals:

the lamination device 100 is provided with a lamination device,

a membrane unwinding 101, a membrane coating 102, a first oven 103, a pole piece bonding 104, a second oven 105,

a group of pole pieces 200 is shown,

the diaphragm 1, the first pole piece 2, the second pole piece 3, compress tightly 4.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

A lamination process method according to an embodiment of the present application is described below with reference to fig. 1-13, including at least the following steps:

s1: coating the diaphragm 1 and drying the coated diaphragm 1;

s3: attaching a plurality of prepared first pole pieces 2 to a diaphragm 1, wherein the plurality of first pole pieces 2 are arranged on the diaphragm 1 at intervals;

s5: the starting diaphragm 1 is folded upwards to be coated on the first pole piece 2, and the first second pole piece 3 is folded on the starting diaphragm 1 to form a pole piece group 200;

s7: the pole piece group 200 is turned over to be folded on the diaphragm 1, a new second pole piece 3 is continuously superposed on the pole piece group 200, and the process is continued until the number of the pole pieces in the pole piece group 200 meets the requirement; the first pole piece 2 is a negative pole piece, and the second pole piece 3 is a positive pole piece; or the first pole piece 2 is a positive pole piece, and the second pole piece 3 is a negative pole piece.

In terms of space utilization, the lamination mode has obvious advantages over the winding assembly mode, and conventionally, the electrode plate group 200 is usually manufactured in a Z-shaped lamination mode, but the production efficiency is low, the manufacturing aspect is not mature, and a large amount of time cost and equipment cost are caused. For example: (1) the diaphragm 1 is provided with a coating for improving thermal resistance and adhesion, and in order to enhance the adhesion between the diaphragm 1 and a pole piece, the coating thickness is usually selected to be increased, so that the conductivity of electrolyte ions in the battery is increased, the resistance of the battery is increased, and the battery core is not easy to develop towards high capacity; (2) in order to enhance the bonding strength between the diaphragm 1 and the pole pieces, the pole piece set 200 is preheated and then hot-pressed for shaping, but as part of coating materials are still in a granular state, a good bonding effect cannot be achieved on the thicker pole piece set 200, the capability of inhibiting the contraction of the diaphragm 1 is reduced, the short circuit between the positive pole and the negative pole is very easy to occur after the battery is overheated, and particularly, when an automobile shakes or collides, the staggered layers are very easy to occur between the pole pieces in the battery, so that the safety of the battery is affected; (3) at present, the battery specifications and types are numerous, the diaphragm 1 needs to be cut according to different battery types, the utilization rate of the diaphragm 1 is low, and great resource waste is caused.

Considering that diaphragm 1 belongs to the copolymerization polymer, this factor of stronger copolymerization can take place for the adhesive in its coating of diaphragm 1 after drying, diaphragm 1 after also being dried has better bonding effect, dry diaphragm 1 earlier, then carry out thermal recombination in advance with a plurality of first pole pieces 2, can guarantee that diaphragm 1 surfacing like this, diaphragm 1 and first pole piece 2 bond firmly, can not take place the dislocation, avoid producing the fold in steps such as pole piece group 200 equipment, electric core drying, annotate liquid, influence battery quality.

Simultaneously, because first pole piece 2 carries out thermal recombination with diaphragm 1 in advance before the lamination, just so saved the time of pole piece group 200 hot pressing design, promoted the production efficiency of hot pressing process again greatly when guaranteeing adhesion strength between first pole piece 2, second pole piece 3 and diaphragm 1.

To the problem of the different models of battery, diaphragm 1 production can be carried out according to the size of assembly battery to this application, paints diaphragm 1 according to demand length, improves the utilization ratio of material, reduces unnecessary extravagant, practices thrift the cost.

It should be noted that the plate group 200 mentioned in the present application refers to: the electrode plate group 200 is formed by overlapping one first electrode plate 2 and one second electrode plate 3, or the electrode plate group 200 is formed by overlapping a plurality of first electrode plates 2 and a plurality of second electrode plates 3.

According to the lamination process method, the bonding performance between the diaphragm 1 and the first pole piece 2 is improved, the method can achieve the thermal compounding effect of the first pole piece 2 and the diaphragm 1, the diaphragm 1 cannot shrink due to high temperature, and the safety of the battery is guaranteed; meanwhile, all the first pole pieces 2 are thermally compounded with the diaphragm 1 in advance, and only the second pole pieces 3 need to be superposed in the process, so that the production efficiency of the laminated battery cell is greatly improved.

According to one embodiment of the present application, incomplete drying is employed for the separator 1 in step S1. Specifically, the drying degree of the diaphragm 1 after the diaphragm 1 is dried is 85% -95%; the drying temperature is 30-70 ℃. The coating that incompletely dries has stronger to grab the power of adhering to first pole piece 2, is favorable to strengthening the adhesive force of diaphragm 1 and first pole piece 2, is difficult to take place the dislocation.

In one embodiment according to the present application, the lamination process further comprises: step S4, the first pole piece 2 and the diaphragm 1 are clamped tightly, and the first pole piece 2 and the diaphragm 1 are dried again. Specifically, the drying temperature for drying the first pole piece 2 and the diaphragm 1 again is 40-90 ℃, and the clamping force between the first pole piece 2 and the diaphragm 1 is 1kgf/cm²-10kgf/cm 2. The incompletely dried diaphragm 1 coating and the first pole piece 2 are dried at high temperature in a clamped state, so that the thermal compounding effect of the first pole piece 2 and the diaphragm 1 is achieved, and the diaphragm 1 cannot shrink due to high temperature.

According to one embodiment of the present application, the length of the separator 1 between two adjacent first pole pieces 2 is L1, the length of the second pole piece 3 is L2, and L1 and L2 satisfy: l1 is more than or equal to 2L 2. As shown in fig. 6 to 12, initially, the diaphragm 1, the first pole piece 2, and the diaphragm 1 are arranged from bottom to top, the second pole piece 3 is stacked on the diaphragm 1 and then turned over for the first time, at this time, the diaphragm 1, the second pole piece 3, the diaphragm 1, and the first pole piece 2 are arranged from bottom to top after being turned over again, and then, the diaphragm 1, the first pole piece 2, the diaphragm 1, the second pole piece 3, and the diaphragm 1 are arranged from bottom to top after being turned over again, and at this time, the diaphragm is stacked on the first pole piece 2 which has been previously pasted in the step S3, so that the length L1 of the diaphragm 1 between two adjacent first pole pieces 2 is not less than twice the length L2 of the second pole piece 3, and thus the lamination process method of the present application can be implemented.

In one embodiment according to the present application, L1 satisfies: l2 is more than or equal to 320mm and less than or equal to 1200mm, and L2 meets the following requirements: l2 is more than or equal to 160mm and less than or equal to 600 mm. The spacing between the first pole piece 2 and the alignment degree of the first pole piece 2 and the boundary of the diaphragm 1 can be determined according to the size of an actual product.

The lamination device 100 according to an embodiment of the present application includes: the device comprises a membrane unwinding roll 101, a membrane coating member 102, a pole piece pasting member 104, a first oven 103 and a second oven 105.

Specifically, the membrane coating member 102 is disposed downstream of the membrane unwinding 101 and is adapted to coat the membrane 1; the first oven 103 is disposed downstream of the separator-coated member 102 and adapted to dry the separator 1; the pole piece pasting piece 104 is arranged at the downstream of the first oven 103 and is suitable for pasting the negative pole piece or the positive pole piece on the diaphragm 1; the second oven 105 is disposed downstream of the first oven 103 and is adapted to dry the negative electrode sheet or the separator 1 provided with the negative electrode sheet.

It should be noted that downstream in this application refers to the direction of the steps, and it is understood that the next device flow is performed after the device completes all the flows.

Further, the width of the separator 1 is related to the size of the laminated cell product, and the coating method may use dip coating, roll coating, knife coating, etc., or a combination thereof.

According to an embodiment of the present application, the first oven 103 may be a hot roller oven, and the drying process is performed by using hot rollers to roll, so as to reduce the thickness of the separator 1 as much as possible while ensuring the coating uniformity of the separator 1, which is beneficial to reducing the internal resistance of the battery.

In one embodiment according to the present application, the lamination device 100 further comprises: and the pressing piece 4 is suitable for pressing the negative plate or the positive plate and the diaphragm 1. After the negative plate or the positive plate is adhered to the diaphragm 1, the pressing piece 4 is used for pressing the negative plate or the positive plate and the diaphragm 1 and sending the negative plate or the positive plate and the diaphragm 1 into the second oven 105 for drying again, the pressing piece 4 is loosened after the drying is finished, the thermal compounding of the negative plate or the positive plate and the diaphragm 1 is finished, and the adhesion force is strong.

According to one embodiment of the application, the thermal compounding step of the negative electrode sheet and the separator 1 is as follows:

1. the separator 1 is coated in the separator coating member 102;

2. after the coating is finished, a hot roller oven is adopted to carry out incomplete drying on the coated diaphragm 1;

3. attaching the prepared negative plate to the incompletely dried diaphragm 1;

4. after the negative electrode sheet is attached to the separator 1, it is clamped by using a clamping tool, and then secondary drying is performed in a second oven 105.

According to one embodiment of the present application, pole piece set 200 is stacked as follows:

1. folding the starting diaphragm 1 upwards to cover the first negative plate;

2. then, the positive plate is stacked on the folded diaphragm 1 to complete the lamination of the positive plate, and the 1 st unit plate group 200 is completed as shown in the state of fig. 7;

3. a laminating machine clamping knife clamps the 1 st unit pole piece group 200 and turns over the next negative pole piece direction, and the folded pole piece group 200 is obtained;

4. then taking and overlapping a new positive plate on the unit pole plate group 200 of the No. 1, and turning over the next negative plate in the direction;

5. then, turning over to form a 2 nd unit pole piece group 200;

6. in this way, the stack is folded layer by layer, and the entire stack 200 is completed.

In the description of the present application, it is to be understood that the terms "length," "width," "thickness," "upper," "lower," and the like, as used herein, refer to an orientation or positional relationship as shown in the drawings, which is used for convenience in describing the present application and to simplify the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present application.

In the description of the present application, "the first feature" and "the second feature" may include one or more of the features.

In the description of the present application, "a plurality" means two or more.

In the description of the present application, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, and may also include the first and second features being in contact not directly but via another feature therebetween.

In the description of the present application, the first feature being "on," "above" and "over" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is at a higher level than the second feature.

In the description herein, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A lamination process method is characterized by comprising at least the following steps:

s1: coating the diaphragm (1) and incompletely drying the coated diaphragm (1);

s3: attaching a plurality of prepared first pole pieces (2) to the diaphragm (1), wherein the first pole pieces (2) are arranged on the diaphragm (1) at intervals;

s4: clamping the first pole piece (2) and the diaphragm (1) and drying the first pole piece (2) and the diaphragm (1) again;

s5: the starting diaphragm (1) is folded upwards to be coated on the first pole piece (2), and the first second pole piece (3) is folded on the starting diaphragm (1) to form a pole piece group (200);

s7: turning over the pole piece group (200) to be folded on the diaphragm (1), continuously superposing a new second pole piece (3) on the pole piece group (200), and continuing the process until the number of the pole pieces in the pole piece group (200) meets the requirement; wherein

The first pole piece (2) is a negative pole piece, and the second pole piece (3) is a positive pole piece; or the first pole piece (2) is a positive pole piece, and the second pole piece (3) is a negative pole piece;

the length of the diaphragm (1) between two adjacent first pole pieces (2) is L1, the length of the second pole piece (3) is L2, and the L1 and the L2 satisfy the following conditions: l1 is more than or equal to 2L 2.

2. The lamination process method according to claim 1, wherein the drying degree of the separator (1) after the drying of the separator (1) is 85% -95% in step S1.

3. The lamination process method according to claim 1, wherein in step S1, the drying temperature is 30 ℃ to 70 ℃.

4. The lamination process according to claim 1, wherein (a) is applied to the first pole piece2) The drying temperature for drying the diaphragm (1) again is 40-90 ℃, and the clamping force between the first pole piece (2) and the diaphragm (1) is 1kgf/cm²-10kgf/cm²。

5. The lamination process method according to claim 1, wherein the L1 satisfies: 320mm ≦ L2 ≦ 1200mm, the L2 satisfying: l2 is more than or equal to 160mm and less than or equal to 600 mm.

6. A lamination device for performing the lamination process of any one of claims 1 to 5, comprising:

unwinding a membrane (101);

a membrane application member (102), the membrane application member (102) being disposed downstream of the membrane unwinding roll (101) and adapted to apply a membrane (1);

a first oven (103), said first oven (103) being arranged downstream of said membrane-coated piece (102) and being adapted to dry said membrane (1);

the pole piece pasting piece (104) is arranged at the downstream of the first oven (103) and is suitable for pasting a negative pole piece or a positive pole piece on the diaphragm (1);

a second oven (105), said second oven (105) being arranged downstream of said first oven (103) and being suitable for drying said separator (1) provided with negative or positive plates;

further comprising: and the pressing piece (4) is suitable for pressing the negative electrode plate or the positive electrode plate and the diaphragm (1).