CN111628226A - Lamination process and lamination device - Google Patents

Abstract

The present application discloses a lamination process method and lamination device. The lamination process method includes at least the following steps: S1: coating a diaphragm and drying the coated diaphragm; S3: attaching The prepared plurality of first pole pieces are arranged at intervals on the diaphragm; S5: stack the initial diaphragm upward to cover the first first pole piece, and stack the first second pole piece On the initial diaphragm to form a pole piece group; S7: flip the pole piece group to fold on the diaphragm, and continue to superimpose a new second pole piece on the pole piece group, and continue the above process until the number of pole pieces in the pole piece group The requirements are met; wherein 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 of the present application improves the bonding performance between the separator and the first pole piece, ensures the safety of the battery, and greatly improves the production efficiency of the lamination cell.

Description

Lamination process method and lamination device

technical field

The present application relates to the field of battery technology, and in particular, to a lamination process method and lamination device.

Background technique

At present, there are two main methods for preparing cells of lithium ion batteries: winding and stacking. The lamination process is to alternately stack positive electrode sheets, separators and negative electrode sheets. Many companies will hot-press the pole piece group before the cell is packaged, so that the temperature inside and outside the pole piece group will rise to soften the PVDF glue particles on the diaphragm coating, and the diaphragm and the pole piece will be fully bonded to achieve the purpose of shaping . However, due to insufficient heating temperature, some PVDF glue particles have been solidified, which cannot achieve a good bonding effect for some thicker pole pieces, resulting in dislocation of the separator and pole pieces, which affects the safety of the battery.

Application content

The present application aims to solve at least one of the technical problems existing in the prior art.

Therefore, one purpose of the present application is to propose a lamination process method, which can enhance the bonding performance between the separator and the first pole piece, and improve the safety of the battery;

Another object of the present application is to provide a lamination device, which can use the above lamination process to prepare battery cells.

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

S1: coating the diaphragm and drying the coated diaphragm;

S3: Attach a plurality of prepared first pole pieces to the diaphragm, and the plurality of first pole pieces are arranged at intervals on the diaphragm;

S5: stack the initial diaphragm upward to cover the first first pole piece, and stack the first second pole piece on the initial diaphragm to form a pole piece group;

S7: Turn the pole piece set over to be folded on the diaphragm, and continue to superimpose a new second pole piece on the pole piece set, and continue the above process until the number of pole pieces in the pole piece set meets the requirements; wherein the first pole piece is a negative electrode, the second electrode is a positive electrode; or the first electrode is a positive electrode, and the second electrode is a negative electrode.

The lamination process method of the present application improves the bonding performance between the diaphragm and the first pole piece. This method can not only achieve the thermal composite effect of the first pole piece and the diaphragm, but also does not cause the diaphragm to shrink due to high temperature, ensuring that The safety of the battery; at the same time, since all the first pole pieces are thermally compounded with the separator in advance, only the second pole piece needs to be superimposed in the process, which greatly improves the production efficiency of the laminated cell.

Further, in step S1, incomplete drying is used for the diaphragm.

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

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

Further, the method further includes: 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 re-drying the first pole piece and the diaphragm is 40°C-90°C, and the clamping force between the first pole piece and the diaphragm is 1kgf/cm ² -10kgf/cm ² .

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≧2L2.

Further, the L1 satisfies: 320mm≤L2≤1200mm, and the L2 satisfies: 160mm≤L2≤600mm.

Another aspect of the present application provides a lamination device, comprising: a diaphragm unwinding; a diaphragm coating member, the diaphragm coating member is disposed downstream of the diaphragm unwinding and is suitable for coating the diaphragm; first an oven, the first oven is arranged downstream of the membrane coating member and is suitable for drying the membrane; a pole piece sticker, the pole piece sticker is arranged downstream of the first oven and is suitable for drying the membrane For sticking the negative electrode sheet or the positive electrode sheet on the diaphragm; a second oven, the second oven is arranged downstream of the first oven and is suitable for drying the diaphragm provided with the negative electrode sheet or the negative electrode sheet .

Further, it also includes: a pressing member suitable for pressing the negative electrode sheet or the positive electrode sheet and the separator.

Additional aspects and advantages of the present application will be set forth, in part, from the following description, and in part will become apparent from the following description, or may be learned by practice of the present application.

Description of drawings

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

1 is a schematic diagram of a lamination device according to an embodiment of the present application;

2 is a flowchart of a lamination process method according to an embodiment of the present application;

3 is a schematic diagram of thermal recombination of a first pole piece and a diaphragm according to an embodiment of the present application;

FIG. 4 is a schematic flow chart 1 of a lamination process method according to an embodiment of the present application;

5 is a second schematic flow chart of a lamination process method according to an embodiment of the present application;

FIG. 6 is a schematic flow chart 3 of a lamination process method according to an embodiment of the present application;

7 is a schematic diagram 4 of a lamination process method according to an embodiment of the present application;

FIG. 8 is a schematic flow chart 5 of a lamination process method according to an embodiment of the present application;

FIG. 9 is a schematic flow chart 6 of a lamination process method according to an embodiment of the present application;

FIG. 10 is a schematic flow chart 7 of a lamination process method according to an embodiment of the present application;

FIG. 11 is a schematic flow chart 8 of a lamination process method according to an embodiment of the present application;

FIG. 12 is a schematic flow chart 9 of a lamination process method according to an embodiment of the present application;

13 is a schematic diagram of a laminated pole piece group fabricated by a lamination process method according to an embodiment of the present application.

Reference number:

Lamination device 100,

Diaphragm unwinding 101, diaphragm coating member 102, first oven 103, pole piece bonding member 104, second oven 105,

pole piece set 200,

Diaphragm 1, first pole piece 2, second stage piece 3, pressing member 4.

Detailed ways

The following describes in detail the embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, but should not be construed as a limitation on the present application.

The following describes a lamination process method according to an embodiment of the present application with reference to FIGS. 1 to 13 , including at least the following steps:

S1: coating the diaphragm 1 and drying the coated diaphragm 1;

S3: Attach a plurality of prepared first pole pieces 2 to the diaphragm 1, and the plurality of first pole pieces 2 are arranged on the diaphragm 1 at intervals;

S5: stack the initial diaphragm 1 upward to cover the first first pole piece 2, and stack the first second pole piece 3 on the initial diaphragm 1 to form a pole piece group 200;

S7: Turn the pole piece set 200 over to be folded on the diaphragm 1, and continue to superimpose a new second pole piece 3 on the pole piece set 200, and continue the above process until the number of pole pieces in the pole piece set 200 meets the requirements; One 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 method has obvious advantages over the winding method. Traditionally, the Z-shaped lamination method is usually used to make the pole piece group 200, but its production efficiency is low, and the production is not mature, resulting in a lot of cost. time cost and equipment cost. For example: (1) There is a coating with improved thermal resistance and adhesion on the separator 1. In order to strengthen the adhesion between the separator 1 and the pole piece, the thickness of the coating is usually increased, which will lead to the conductivity of the electrolyte ions in the battery. increase, resulting in an increase in battery resistance, and it is not easy for cells to develop in the direction of high capacity; (2) In order to strengthen the bonding strength between the diaphragm 1 and the pole piece, the pole piece group 200 is preheated first and then hot-pressed. However, since part of the coating material is still in the form of particles, it cannot achieve a good bonding effect for the thicker pole piece group 200, and the ability to suppress the shrinkage of the diaphragm 1 is reduced. When the car is vibrated or collided, the pole pieces inside the battery are easily dislocated, which will affect the safety of the battery; (3) At present, there are many battery specifications and models, and the diaphragm 1 needs to be cut for different battery models, resulting in the diaphragm 1. The low utilization rate results in a large waste of resources.

Considering that the separator 1 is a copolymeric polymer, the adhesive in the coating of the separator 1 will have a stronger copolymerization effect after drying, that is, the dried separator 1 has a better bonding effect. The diaphragm 1 is dried, and then thermally compounded with a plurality of first pole pieces 2 in advance, so as to ensure that the surface of the diaphragm 1 is flat, the diaphragm 1 and the first pole piece 2 are firmly bonded, and no dislocation occurs, so as to avoid the occurrence of misalignment between the pole pieces. Wrinkles are generated in the steps of assembling the group 200, drying the cells, and injecting liquid, which affects the quality of the cells.

At the same time, since the first pole piece 2 and the diaphragm 1 are thermally compounded in advance before lamination, the time for hot pressing and shaping of the pole piece group 200 is saved, and the first pole piece 2, the second pole piece 3 and the diaphragm 1 are ensured. At the same time, the production efficiency of the hot pressing process is greatly improved.

In view of the problem of different types of batteries, the present application can produce the separator 1 according to the size of the assembled battery, and apply the separator 1 according to the required length to improve the utilization rate of materials, reduce unnecessary waste, and save costs.

It should be noted that the pole piece group 200 mentioned in this application refers to: a pole piece group 200 formed by superimposing a first pole piece 2 and a second pole piece 3, or a plurality of first pole pieces 2 and a plurality of A pole piece group 200 is formed by stacking the second pole pieces 3 .

According to the lamination process method of the present application, the bonding performance between the diaphragm 1 and the first pole piece 2 is improved, and this method can not only achieve the thermal composite effect of the first pole piece 2 and the diaphragm 1, but also avoid high temperature Causes the diaphragm 1 to shrink to ensure the safety of the battery; at the same time, since all the first pole pieces 2 are thermally compounded with the diaphragm 1 in advance, only the second pole piece 3 needs to be superimposed in the process, which greatly improves the production of laminated cells efficiency.

According to an embodiment of the present application, in step S1, the diaphragm 1 is partially dried. Specifically, the drying degree of the diaphragm 1 after drying the diaphragm 1 is 85%-95%; the drying temperature is 30°C-70°C. The incompletely dried coating has stronger adhesion to the first pole piece 2, which is beneficial to strengthen the adhesion between the diaphragm 1 and the first pole piece 2, and is not prone to dislocation.

According to an embodiment of the present application, the lamination process method further includes: step S4 , clamping the first pole piece 2 and the diaphragm 1 and drying the first pole piece 2 and the diaphragm 1 again. Specifically, the drying temperature for re-drying the first pole piece 2 and the diaphragm 1 is 40°C-90°C, and the clamping force between the first pole piece 2 and the diaphragm 1 is 1kgf/cm ² -10kgf/cm 2 . The coating of the diaphragm 1 that is not completely dried and the first pole piece 2 are dried at high temperature in a clamped state, so that the thermal composite effect of the first pole piece 2 and the diaphragm 1 is achieved, and at the same time, it will not be caused by high temperature. Diaphragm 1 contracts.

According to an embodiment of the present application, 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 L1 and L2 satisfy: L1≥2L2. As shown in Fig. 6-Fig. 12, initially the diaphragm 1, the first pole piece 2, and the diaphragm 1 are from bottom to top. After stacking the second pole piece 3 on the diaphragm 1, it is turned over for the first time. At this time, from bottom to top The top is the diaphragm 1, the second pole piece 3, the diaphragm 1, and the first pole piece 2. After turning over again, from the bottom to the top are the diaphragm 1, the first pole piece 2, the diaphragm 1, the second pole piece 3, and the diaphragm 1. When At this time, it is superimposed with the first pole piece 2 that has been pasted in advance in step S3, so the length L1 of the diaphragm 1 between the two adjacent first pole pieces 2 is required to be ≥ twice the second pole piece 3 Length L2, so that the lamination process method of the present application can be realized.

According to an embodiment of the present application, L1 satisfies: 320mm≤L2≤1200mm, and L2 satisfies: 160mm≤L2≤600mm. The interval between the first pole piece 2 and the first pole piece 2 and the alignment between the first pole piece 2 and the boundary of the diaphragm 1 can be determined according to the size of the actual product.

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

Specifically, the diaphragm coating member 102 is disposed downstream of the diaphragm unwinding 101 and is suitable for coating the diaphragm 1; the first oven 103 is disposed downstream of the diaphragm coating member 102 and is suitable for drying the diaphragm 1; The sheet sticking member 104 is arranged downstream of the first oven 103 and is suitable for sticking the negative electrode sheet or the positive electrode sheet on the separator 1; The separator 1 is dried.

It should be noted that the downstream in this application refers to the step direction, which can be understood as the next device process after the device completes all the processes.

Further, the width of the separator 1 is related to the size of the laminated cell product, and the coating method can be dip coating, roller coating, blade coating, etc., or a combination of these methods can be used.

According to an embodiment of the present application, the first oven 103 may be a hot roller oven oven, and a hot roller is used for rolling during the drying process, so as to ensure the uniformity of the coating of the diaphragm 1 and reduce the thickness of the diaphragm 1 as much as possible , which is beneficial to reduce the internal resistance of the battery.

According to an embodiment of the present application, the lamination device 100 further includes: a pressing member 4 suitable for pressing the negative electrode sheet or the positive electrode sheet and the separator 1 . After the negative electrode sheet or the positive electrode sheet is pasted on the separator 1, the negative electrode sheet or the positive electrode sheet and the separator 1 are pressed by the pressing member 4 and sent to the second oven 105 for drying again. After the drying is completed, the pressure is released. Tightening member 4, at this time, the negative electrode sheet or the positive electrode sheet and the separator 1 are thermally recombined and have strong adhesion.

According to an embodiment of the present application, the steps of thermal recombination of the negative electrode sheet and the separator 1 are as follows:

1. The diaphragm 1 is coated in the diaphragm coating member 102;

2. After the coating is completed, a hot roller oven is used to incompletely dry the coated diaphragm 1;

3. Attach the prepared negative electrode sheet to the incompletely dried diaphragm 1;

4. After the negative electrode sheet is attached to the separator 1, use a clamping tool to clamp it, and then perform secondary drying in the second oven 105.

According to an embodiment of the present application, the stacking manner of the pole piece group 200 is as follows:

1. Fold the starting diaphragm 1 upward and wrap it on the first negative electrode sheet;

2. Then stack the positive electrode sheet on the folded separator 1 to complete the stacking of the positive electrode sheet, as shown in Figure 7, to complete the first unit electrode group 200;

3. Clamp the pole piece group 200 of the first unit and fold it in the direction of the next negative pole piece, and the pole piece group 200 after the folding is completed;

4. Then take and stack the new positive electrode sheet on the first unit electrode group 200, and then fold the next negative electrode sheet in the direction;

5. Fold over again to form the second unit pole piece group 200;

6. Fold the layers one by one in this way to complete the entire pole piece group 200 .

In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "thickness", "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings , is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present application.

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

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

In the description of this application, a first feature being "above" or "under" a second feature may include that the first and second features are in direct contact, or that the first and second features are not in direct contact but through them Additional feature contacts between.

In the description of this application, the first feature "above", "over" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is level higher than Second feature.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples", etc., is meant to incorporate the embodiments A particular feature, structure, material, or characteristic described by an example or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms 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.

Although the 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 in these embodiments without departing from the principles and spirit of the present application, The scope of the application is defined by the claims and their equivalents.

Claims (10)

1. A lamination process method is characterized by comprising 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 the diaphragm (1), wherein the 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: 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.

2. The lamination process according to claim 1, wherein incomplete baking is applied to the separator (1) in step S1.

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

4. The lamination process method according to claim 2, wherein in step S1, the drying temperature is 30 ℃ to 70 ℃.

5. The lamination process method according to claim 2, further comprising: and step S4, clamping the first pole piece (2) and the diaphragm (1) and drying the first pole piece (2) and the diaphragm (1) again.

6. The lamination process method according to claim 5, wherein 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/cm²。

7. The lamination process according to claim 1, wherein 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: l1 is more than or equal to 2L 2.

8. The lamination process method according to claim 7, 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.

9. A lamination assembly, 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 plates or negative plates.

10. The lamination device according to claim 9, further comprising: and the pressing piece (4) is suitable for pressing the negative plate or the positive plate and the diaphragm (1).

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