CN112421129A

CN112421129A - Battery cell manufacturing equipment and method thereof

Info

Publication number: CN112421129A
Application number: CN202110092798.7A
Authority: CN
Inventors: 阳超; 张小畏; 唐鸣浩; 林文法
Original assignee: Jiangsu Contemporary Amperex Technology Ltd
Current assignee: Jiangsu Contemporary Amperex Technology Ltd
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2021-02-26
Anticipated expiration: 2041-01-25
Also published as: CN112421129B

Abstract

The application relates to a battery cell manufacturing device and a method thereof. The battery cell manufacturing equipment is used for manufacturing the battery cell, the battery cell comprises a first pole piece, a second pole piece and a diaphragm, the battery cell is provided with a winding starting section positioned on the inner side, and the battery cell manufacturing equipment comprises: the winding needle is configured to wind the first pole piece, the second pole piece and the diaphragm to form a battery core; and the blanking assembly is configured to take the battery cell down from the winding needle, and comprises an inner heating needle which is configured to press against and heat the winding starting section so as to thermally compound at least one of the first pole piece and the second pole piece of the winding starting section with the diaphragm. The application provides a battery core manufacturing equipment, aims at solving the problem that lithium is separated out in the inner ring part of a battery core.

Description

Battery cell manufacturing equipment and method thereof

Technical Field

The application relates to the technical field of batteries, in particular to a battery core manufacturing device and a method thereof.

Background

In the production process of the battery, the pole piece and the diaphragm need to be wound into a battery core by using winding equipment. And in the initial winding step, the winding needle can wind a certain number of layers of diaphragms in advance, then the pole piece is conveyed to the winding needle, and finally the pole piece and the diaphragms are wound together by the winding needle to form the battery core. The electric core after coiling and prepressing shaping is in a flat structure. However, in the use process of the battery cell after winding and pre-pressing for shaping, the lithium precipitation condition exists at the inner ring part, which affects the use safety of the battery cell.

Disclosure of Invention

The application provides a battery cell manufacturing device and a method thereof, aiming at solving the problem that lithium is separated out at the inner ring part of a battery cell.

On the one hand, this application provides a battery core manufacture equipment for make electric core, electric core include first pole piece, second pole piece and diaphragm, and electric core has the initial section of coiling that is located the inboard, and battery core manufacture equipment includes: the winding needle is configured to wind the first pole piece, the second pole piece and the diaphragm to form a battery core; and the blanking assembly is configured to take the battery cell down from the winding needle, and comprises an inner heating needle which is configured to press against and heat the winding starting section so as to thermally compound at least one of the first pole piece and the second pole piece of the winding starting section with the diaphragm.

According to the battery cell manufacturing equipment provided by the embodiment of the application, the battery cell is formed by winding the first pole piece, the second pole piece and the diaphragm through the winding needle. And (4) taking the battery core off the winding needle by using the blanking assembly. The inner heating needle of the blanking assembly can heat the winding starting section to enable at least one of the first pole piece and the second pole piece to be in thermal composite connection with the diaphragm, so that the diaphragm is not in a free state any more, but is restrained by the first pole piece and/or the second pole piece. After the battery cell taken down is stretched to be flat by the blanking assembly, the diaphragm positioned at the inner ring part is restrained, so that the diaphragm at the inner ring part is not easy to retract after the blanking assembly is moved away, the possibility that the positive plate and the negative plate are driven to move inwards due to retraction of the diaphragm, the gap between the positive plate and the negative plate at the inner ring part is too large, and the possibility of lithium precipitation is reduced.

According to an embodiment of the present application, the inside heating pin includes a first abutting surface and a second abutting surface which are oppositely disposed in a vertical direction, at least one of the first abutting surface and the second abutting surface is a horizontal plane, and the inside heating pin thermally recombines the winding start section of the battery cell through the at least one of the first abutting surface and the second abutting surface.

In the embodiment that the first pressing surface and/or the second pressing surface are horizontal surfaces, the horizontal surfaces can be well contacted and attached with the battery cell, so that on one hand, the heating effect is good, the possibility that gaps are generated due to poor attachment between the first pressing surface and/or the second pressing surface and the battery cell to cause uneven heating effect is reduced, on the other hand, when pressure is applied to the battery cell from the outer side of the battery cell, the horizontal surfaces can well support the preset area of the battery cell, the problem of stress concentration is not prone to occurring in the area where the horizontal surfaces are contacted with the battery cell, and the possibility that cracks occur due to stress concentration in at least one of the first pole piece, the second pole piece and the diaphragm is reduced.

According to an embodiment of the present application, a width of an orthogonal projection of at least one of the first abutting surface and the second abutting surface in the vertical direction is smaller than a width of an orthogonal projection of the inside heating pin in the vertical direction, the width being a dimension measured in a direction perpendicular to an axial direction of the battery cell.

The first abutting surface or the second abutting surface is small in area, the pressure of inner side heating to the battery cell can be increased under the condition that the pressure applied to the outer side of the battery cell has the requirement of an upper limit value, contact fitting between the inner side heating needle and the battery cell is guaranteed, and firm bonding between at least one of the first pole piece and the second pole piece and the melting part of the diaphragm under the action of preset pressure is guaranteed.

According to an embodiment of the present application, the cell manufacturing apparatus further includes a first pressing plate and a second pressing plate, and the first pressing plate and the second pressing plate are configured to press the cell from both sides of the cell, respectively, in a vertical direction.

The first pressing plate and the second pressing plate apply pressure to the battery cell from two sides of the battery cell respectively, so that the stress on the upper side and the lower side of the inner side heating needle is balanced, the possibility that the inner side heating needle is bent or deformed upwards or downwards is reduced, and the requirement on the self bending deformation resistance of the inner side heating needle is reduced.

According to an embodiment of the application, the inboard heating needle includes that the third supports the face and the second supports the face along the relative first face and the second that set up of vertical direction, and the third supports the face and connects first face and the second that supports the face, and the third supports the face and is the arcwall face, and the inboard heating needle supports the initial section thermal recombination of coiling of pressing the face to electric core through the third.

Because the third is the arcwall face, consequently electric core can support the pressure face laminating with the third well, thereby it is good to be favorable to guaranteeing that the heating effect is good on the one hand, reduce the third and support and press the gap and lead to the inhomogeneous possibility of heating effect to appear in the laminating harmfully between face and the electric core, on the other hand, when exerting pressure to electric core from the outside of electric core, the arcwall face can form good support to electric core, make the area of arcwall face and electric core contact difficult the stress concentration problem of appearing, reduce first pole piece, at least one of second pole piece and diaphragm is because of the possibility that the crackle appears in the stress concentration.

According to an embodiment of the application, the blanking assembly further comprises an outer clamping pin configured to clamp the winding start section with the third abutting surface.

After the cell is formed by winding on the winding needle, the inner heating needle and the outer clamping needle can clamp the predetermined region of the cell from the inner side and the outer side of the cell respectively. The electric core is restrained by the inner side heating needle and the outer side clamping needle, so that the first pole piece, the second pole piece and the diaphragm cannot slide or be dislocated mutually.

According to one embodiment of the application, the inside heating needle comprises a body and a release layer, at least part of the outer surface of the body is covered with the release layer, and the release layer is configured to abut against the winding start section.

After the heating is finished to the winding initial section of the battery cell by the inner side heating, because the anti-sticking layer of the inner side heating needle has the anti-sticking effect, the inner side heating needle is not easy to stick to the melting area of the diaphragm, and the possibility that the inner side heating needle is difficult to pull out the needle or the winding initial section is pulled when the inner side heating needle sticks to the winding initial section is reduced.

According to one embodiment of the present application, the inside heater pin includes a body configured to press against the winding start section, and a heater configured to heat the body to thermally compound the winding start section of the cell by the body.

The heater indirectly heats the winding initial section of the battery cell through the body. Because the inner side heating needle needs to have good bending resistance, the integral bending resistance requirement of the inner side heating needle can be met by increasing the rigidity of the body, and the integral bending resistance requirement of the inner side heating needle is met without the rigidity of the heater, so that the structural strength requirement of the heater is reduced, and the manufacturing difficulty of the heater is reduced.

According to one embodiment of the application, the body is a hollow structure, and at least part of the heater is accommodated in the body.

The heater sets up in the inside mode of body for the heater can realize easily that each regional heating state to the body keeps unanimous, thereby guarantees that each regional temperature rise of body keeps unanimous, is favorable to reducing because of the regional uneven possibility that leads to the heating effect of electric core diaphragm to have the difference that appears in the temperature of body and electric core contact, and then reduces the possibility that at least one of first pole piece, second pole piece and diaphragm are in the firm degree difference of heating region adhesion.

According to an embodiment of the application, the inside heating needle further comprises a temperature sensor configured to monitor a temperature of the body.

The temperature of the body can be monitored in real time through the temperature sensor, whether the temperature of the body is at the preset temperature or not is convenient to judge, and the possibility that the thermal compound effect is deteriorated due to the fact that the temperature of the body is higher or lower is facilitated to be reduced.

In another aspect, a method for manufacturing a battery cell is provided according to the present application, which includes:

manufacturing a battery cell;

and heating the winding starting section of the battery core to thermally compound at least one of the first pole piece and the second pole piece of the winding starting section with the diaphragm.

The cell manufacturing method of the embodiment of the application is used for manufacturing the cell of the embodiment. In the method for manufacturing the battery cell, the first pole piece, the second pole piece and the diaphragm are wound to form the battery cell, and then the battery cell is stretched to be flat. And heating the winding starting section to enable at least one of the first pole piece and the second pole piece to be in thermal compound connection with the diaphragm, so that the diaphragm is not in a free state any more, but is restrained by the first pole piece and/or the second pole piece. Because the diaphragm positioned at the inner ring part is restrained, the diaphragm at the inner ring part is not easy to retract, so that the possibility that the positive plate and the negative plate of the inner ring part are too large in gap with each other due to the fact that the positive plate and the negative plate are driven to move inwards due to the retraction of the diaphragm is reduced, and the possibility of the lithium precipitation problem is further reduced.

According to an embodiment of the present application, the cell manufacturing method further includes: and the battery cell is pressed from two sides of the battery cell along the vertical direction.

Support from the both sides of electricity core and press electric core to the flat degree of increase electricity core makes electric core reach predetermined flat degree, satisfies the product requirement.

According to an embodiment of the present application, in the step of heating the winding start section of the battery cell to thermally compound at least one of the first pole piece and the second pole piece of the winding start section with the separator, the heating time is 2 seconds to 5 seconds.

When the heating time is less than 2 seconds, there is a possibility that the heating time is short and the degree of melting of the separator does not meet a predetermined requirement, thereby causing poor thermal recombination effect or thermal recombination failure. If the heating time is longer than 5 seconds, the heating time may be long, and the degree of melting of the separator may exceed a predetermined level, thereby causing breakage of the separator and failure of the separator.

According to an embodiment of the present application, in the step of heating the winding start section of the battery cell to thermally compound at least one of the first pole piece and the second pole piece of the winding start section with the separator, the heating temperature is 85 degrees to 95 degrees.

When the heating temperature is lower than 85 degrees, there is a possibility that the heating temperature is low and the degree of melting of the separator does not meet a predetermined requirement, thereby causing poor thermal recombination effect or thermal recombination failure. When the heating temperature is higher than 95 degrees, the heating temperature is high, and the degree of melting of the separator exceeds a predetermined level, and the separator may be broken and fail.

According to one embodiment of the application, in the step of heating the winding starting section of the battery cell to thermally compound at least one of the first pole piece and the second pole piece of the winding starting section with the membrane, a compressive stress of 3 mpa or more and 10 mpa or less is applied to the winding starting section heating region.

When the compressive stress applied to the heating area of the winding starting section is less than 3 MPa, the extrusion force applied to at least one of the first pole piece and the second pole piece and the diaphragm does not meet the preset pressure requirement, so that the adhesion firmness of the at least one of the first pole piece and the second pole piece and the molten part of the diaphragm does not meet the preset requirement, and further the possibility that the at least one of the first pole piece and the second pole piece and the diaphragm are separated again after thermal compounding is completed exists. When the compressive stress applied to the heating region of the winding starting section is greater than 10 mpa, on one hand, the applied extrusion force exceeds the predetermined pressure requirement, so that at least one of the first pole piece, the second pole piece and the diaphragm is subjected to an overlarge force to cause the possibility of structural damage, and on the other hand, the requirement on the bending resistance of the component for applying pressure to the battery cell is high, so that the difficulty in manufacturing and using the component is increased.

Drawings

Features, advantages and technical effects of exemplary embodiments of the present application will be described below by referring to the accompanying drawings.

FIG. 1 is a schematic view of a winding needle winding a first pole piece, a second pole piece, and a diaphragm according to an embodiment of the present application;

FIG. 2 is a schematic view of a winding needle of an embodiment of the present application completing winding;

fig. 3 is a schematic diagram of a blanking assembly clamping a battery cell according to an embodiment of the present application;

fig. 4 is a schematic diagram of a tensile cell of a blanking assembly according to an embodiment of the present application;

FIG. 5 is a schematic side view of an embodiment of the present application showing an inner heating tip;

fig. 6 is a schematic diagram of cell pre-compression molding according to an embodiment of the present application;

fig. 7 is a schematic partial structure diagram of a blanking assembly clamping battery cell according to an embodiment of the present application;

FIG. 8 is a schematic side view of an inner heating tip according to another embodiment of the present application;

FIG. 9 is a partial schematic view of an inner heater pin according to an embodiment of the present application;

fig. 10 is a schematic flow chart of a cell manufacturing method according to an embodiment of the present application.

In the drawings, the drawings are not necessarily drawn to scale.

Description of the labeling:

10. an electric core; 10a, winding an initial section; 10b, a bending area; 11. a first pole piece; 12. a second pole piece; 13. a diaphragm;

20. coiling a needle; 201. a first abdicating groove; 202. a second abdicating groove; 21. a first half shaft; 22. a second half shaft;

30. a blanking assembly;

31. an inside heating pin;

31a, a body; 31b, an anti-sticking layer; 31c, a heater; 31d, a temperature sensor;

311. a first abutting surface; 312. a second pressing surface; 313. a third pressing surface;

32. clamping the needle at the outer side;

40. a first platen;

50. a second platen;

x, horizontal direction; y, vertical direction; z, axial direction.

Detailed Description

Embodiments of the present application will be described in further detail below with reference to the drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the application and are not intended to limit the scope of the application, i.e., the application is not limited to the described embodiments.

In the description of the present application, it is to be noted that, unless otherwise specified, "a plurality" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," and the like, indicate an orientation or positional relationship that is merely for convenience in describing the application and to simplify the description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the application. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. "vertical" is not strictly vertical, but is within the tolerance of the error. "parallel" is not strictly parallel but within the tolerance of the error.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The following description is given with the directional terms as they are used in the drawings and not intended to limit the specific structure of the present application. In the description of the present application, it is also to 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; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood as appropriate by one of ordinary skill in the art.

The applicant notices that the lithium analysis problem exists in the inner ring part of the battery cell which is completely wound and subjected to the pre-pressing and shaping process in the using process. The applicant carries out research and analysis on the structure and the processing process of the battery core. The applicant found that the clearance between the positive electrode tab and the negative electrode tab at the inner ring part of the cell was too large, resulting in a problem of lithium deposition. After further research and analysis, the applicant finds that after the battery core is wound, the battery core needs to be clamped by the blanking assembly and taken down from the winding needle, then the taken-down battery core is stretched to be flat by the blanking assembly, then the blanking assembly is moved away, and then the battery core is pre-pressed and shaped. After the battery cell which is taken down is stretched to be flat by the blanking assembly, the diaphragm which is positioned at the inner ring part is stretched to be in a tensioning state. After the blanking assembly is moved away, the diaphragm positioned at the inner ring part is in a free state, so that the diaphragm in a tensioning state can retract, the positive plate and the negative plate are driven to move inwards, and the gap between the positive plate and the negative plate at the inner ring part is overlarge.

Based on the above problems discovered by the applicant, the applicant improves the structure of the cell manufacturing equipment, and the following further describes the embodiments of the present application.

For a better understanding of the present application, embodiments of the present application are described below with reference to fig. 1 to 9.

Referring to fig. 1 and 2, the battery cell manufacturing apparatus according to the embodiment of the present application includes a winding pin 20. The winding needle 20 is configured to wind the first pole piece 11, the second pole piece 12, and the separator 13. The first pole piece 11 and the second pole piece 12 have opposite polarities, one of them is a positive pole piece, and the other is a negative pole piece. The separator 13 is an insulator between the first pole piece 11 and the second pole piece 12. The first pole piece 11, the second pole piece 12 and the diaphragm 13 are wound on the winding needle 20 to form the battery cell 10.

The battery cell 10 includes a winding start section 10a on the inner side. Illustratively, the first pole piece 11, the second pole piece 12, and the separator 13 are wound by the winding needle 20 together into the winding needle 20. The first pole piece 11, the second pole piece 12 and the portion of the diaphragm 13 wound on the winding needle 20 for the first turn form a winding start section 10 a. Alternatively, the winding needle 20 winds the separator 13N times in advance, and then the first pole piece 11 and the second pole piece 12 enter the winding needle 20 and are wound by the winding needle 20, at this time, when the first pole piece 11 and the second pole piece 12 are wound on the winding needle 20 for the first turn, the first pole piece 11, the second pole piece 12 and the separator 13 form a winding start section 10 a. In one example, the value range of N is: n is more than or equal to 1 and less than or equal to 5.

Referring to fig. 2, the battery cell manufacturing apparatus according to the embodiment of the present application further includes a blanking assembly 30. The blanking assembly 30 is configured to remove the battery cell 10 from the winding needle 20. The blanking assembly 30 includes an inside heating pin 31. The inside heater pin 31 is configured to press against and heat the winding start section 10a of the battery cell 10, so that at least one of the first pole piece 11 and the second pole piece 12 of the winding start section 10a is thermally composited with the separator 13. After at least one of the first and

second pole pieces

11 and 12 is thermally combined with the separator 13 at the winding start section 10a, at least one of the first and

second pole pieces

11 and 12 is connected with the separator 13 at the thermal combination region.

The battery cell manufacturing equipment of the embodiment of the application forms the battery cell 10 by winding the first pole piece 11, the second pole piece 12 and the diaphragm 13 through the winding needle 20. The battery core 10 is removed from the winding needle 20 by using the blanking assembly 30. The inside heating needle 31 of the blanking assembly 30 can heat the winding start section 10a to thermally compound at least one of the first pole piece 11 and the second pole piece 12 with the diaphragm 13, so that the diaphragm 13 is no longer in a free state, but is constrained by the first pole piece 11 and/or the second pole piece 12. After the blanking assembly 30 is used for stretching the taken-down battery cell 10 to be flat, the diaphragm 13 located at the inner ring part is restrained, so that the diaphragm 13 at the inner ring part is not easy to retract after the blanking assembly 30 is moved away, the possibility that the positive plate and the negative plate are driven to move inwards due to retraction of the diaphragm 13, the gap between the positive plate and the negative plate at the inner ring part is too large, and the possibility of the lithium precipitation problem is reduced.

In some embodiments, the inside heating needle 31 heats the winding start section 10a of the battery cell 10, so that the heated area on the separator 13 may melt and become sticky, so that at least one of the first pole piece 11 and the second pole piece 12 may adhere to the separator 13 to achieve connection. For example, the inside heating needle 31 may heat a contact area of the inside heating needle 31 and the winding start section 10a of the battery cell 10. Illustratively, the material of the diaphragm 13 includes at least one of polyethylene and polypropylene.

In some embodiments, referring to FIG. 2, the winding pin 20 includes a first half-shaft 21 and a second half-shaft 22. The first half shaft 21 and the second half shaft 22 may move closer to or away from each other. The first half shaft 21 is provided with a first abdicating groove 201. The second half shaft 22 is provided with a second abdicating groove 202. After the winding is completed, the inside heating pins 31 of the feeding assembly 30 may be inserted into the first and

second relief grooves

201 and 202 of the winding pin 20, respectively. After the inside heating needle 31 presses against the winding start section 10a located in the inner circle, the first half shaft 21 and the second half shaft 22 move closer to each other, so that the winding needle 20 is separated from the battery cell 10, and the blanking assembly 30 can remove the battery cell 10 from the winding needle 20.

In some embodiments, referring to fig. 3 and 4, the number of the blanking assemblies 30 may be two. The two blanking assemblies 30 are arranged at intervals along the horizontal direction X. The two blanking assemblies 30 each hold the battery cell 10 at different positions. In the horizontal direction X, the two blanking assemblies 30 are moved away from each other, thereby stretching the battery cell 10 into a flat shape. The region of the battery cell 10 corresponding to the two blanking assemblies 30 forms a bending region 10 b. A flat area is formed between the two bending areas 10 b. The two blanking assemblies 30 can heat two different regions of the winding start 10 a. The inside heating pins 31 may heat the bent region 10b and/or the flat region of the battery cell 10.

In some embodiments, referring to fig. 4 and 5, the inside heating pin 31 includes a first abutting surface 311 and a second abutting surface 312 which are oppositely disposed in the vertical direction Y. The inside heating pin 31 may thermally recombine the winding start section 10a of the battery cell 10 by one of the first abutting surface 311 and the second abutting surface 312. Alternatively, the inside heating pin 31 may be thermally compounded with the winding start section 10a of the battery cell 10 by the first abutting surface 311 and the second abutting surface 312. One of the first abutting surface 311 and the second abutting surface 312 is a horizontal surface. Alternatively, the first abutting surface 311 and the second abutting surface 312 are both horizontal surfaces. In the embodiment that the first pressing surface 311 and/or the second pressing surface 312 are horizontal surfaces, the horizontal surfaces may contact and adhere well to the battery cell 10, so that on one hand, it is beneficial to ensure that the heating effect is good, and the possibility that the heating effect is not uniform due to a gap caused by poor adhesion between the first pressing surface 311 and/or the second pressing surface 312 and the battery cell 10 is reduced, on the other hand, when pressure is applied to the battery cell 10 from the outside of the battery cell 10, the horizontal surfaces may form a good support for a predetermined region of the battery cell 10, so that the stress concentration problem is not likely to occur in the region where the horizontal surfaces contact the battery cell 10, and the possibility that at least one of the first pole piece 11, the second pole piece 12, and the separator 13 cracks due to stress. For example, the first pressing face 311 and the second pressing face 312 may be opposite to the flat region of the battery cell 10 to heat the winding start section 10a of the battery cell 10 at the flat region.

In some embodiments, as shown in fig. 5 and 7, the width of the orthographic projection of one of the first abutting surface 311 and the second abutting surface 312 in the vertical direction Y is smaller than the width of the orthographic projection of the inside heating needle 31 in the vertical direction Y, so that the area of the first abutting surface 311 or the second abutting surface 312 is smaller, and in the case that the pressure applied to the outside of the battery cell 10 has an upper limit requirement, it may be beneficial to increase the pressure of the inside heating needle 31 on the battery cell 10, ensure the contact fit between the inside heating needle 31 and the battery cell 10, and ensure that at least one of the first pole piece 11 and the second pole piece 12 is firmly bonded with the molten part of the separator 13 under the action of a predetermined pressure. Note that the width is a dimension measured in a direction perpendicular to the axial direction Z of the battery cell 10, that is, a dimension measured in the horizontal direction X. The portion of the inside heating pin 31 for inserting the battery cell 10 is provided with a first abutting surface 311 and a second abutting surface 312. In some examples, the width of the orthographic projection of each of the first abutting surface 311 and the second abutting surface 312 in the vertical direction Y is smaller than the width of the orthographic projection of the inside heating needle 31 in the vertical direction Y. The effects achieved are the same as the above-mentioned effects, and are not described in detail here.

In some embodiments, referring to fig. 6, the cell manufacturing apparatus further includes a first pressing plate 40 and a second pressing plate 50. In the vertical direction Y, the first pressing plate 40 and the second pressing plate 50 are configured to press the battery cell 10 from both sides of the battery cell 10, respectively, to perform the pre-press molding on the battery cell 10. The first pressing plate 40 and the first pressing surface 311 may jointly press the battery cell 10, and the second pressing plate 50 and the second pressing surface 312 may jointly press the battery cell 10, so as to ensure that the first pressing plate 40 and the first pressing surface 311, and the second pressing plate 50 and the second pressing surface 312 apply a predetermined pressure to a predetermined area of the battery cell 10, and further ensure that at least one of the first pole piece 11 and the second pole piece 12 and the diaphragm 13 complete thermal recombination smoothly, and ensure that the connection state is stable and reliable. The first pressing plate 40 and the second pressing plate 50 apply pressure to the battery cell 10 from two sides of the battery cell 10, so that the upper side and the lower side of the inside heating needle 31 are stressed in a balanced manner, the possibility that the inside heating needle 31 bends and deforms upwards or downwards is reduced, and the requirement of the inside heating needle 31 on the self-bending deformation resistance is reduced. Illustratively, the surfaces of the first pressing plate 40 and the second pressing plate 50 facing the inside heating pins 31 are horizontal surfaces.

After the first pressing plate 40 and the second pressing plate 50 approach each other and move to a predetermined position, and the inside heating pins 31 of the blanking assembly 30 complete thermal compounding on the winding start section 10a of the battery cell 10, the inside heating pins 31 move inward away from the battery cell 10 and are out of contact with the battery cell 10, and then the blanking assembly 30 moves upward by a predetermined distance and is pulled out of the battery cell 10. The first pressing plate 40 and the second pressing plate 50 continue to approach each other, further pressing the battery cell 10. After the winding start section 10a of the battery cell 10 is heated by the inside heating needle 31 of the blanking assembly 30, at least one of the first pole piece 11 and the second pole piece 12 of the winding start section 10a of the battery cell 10 is connected to the diaphragm 13, and the diaphragm 13 is no longer in a free state, so that the diaphragm 13 of the winding start section 10a does not contract and deform after the blanking assembly 30 is removed from the battery cell 10 and in the process that the first pressing plate 40 and the second pressing plate 50 continue to press the battery cell 10, and the possibility that the clearance between the first pole piece 11 and the second pole piece 12 is too large due to the inward movement of the first pole piece 11 or the second pole piece 12 driven by the contraction and deformation of the diaphragm 13 is reduced.

In some embodiments, referring to fig. 5 and 7, inner heating pin 31 includes third abutting surface 313 and first abutting surface 311 and second abutting surface 312 disposed opposite to each other in vertical direction Y. The third abutting surface 313 connects the first abutting surface 311 and the second abutting surface 312. The third pressing surface 313 is an arc-shaped surface. Referring to fig. 7, the inside heating needle 31 is inserted into the battery cell 10 in the axial direction Z of the battery cell 10. The horizontal direction X, the vertical direction Y, and the axial direction Z of the battery cell 10 are perpendicular to each other. The inside heating pin 31 thermally recombines the winding start section 10a of the electric core 10 through the third pressing surface 313. Because the third supports the pressure face 313 and is the arcwall face, consequently electric core 10 can support the pressure face 313 with the third and laminate well, thereby on the one hand be favorable to guaranteeing that the heating effect is good, reduce the third and support the pressure face 313 and laminate between the electric core 10 and the gap and lead to the inhomogeneous possibility of heating effect that appears badly, on the other hand, when exerting pressure to electric core 10 from the outside of electric core 10, the arcwall face can form good support to electric core 10, make the area that the arcwall face contacted with electric core 10 is difficult for appearing stress concentration problem, reduce at least one in first pole piece 11, second pole piece 12 and the diaphragm 13 and appear the possibility of crackle because of stress concentration. Illustratively, when the blanking assembly 30 stretches the battery cell 10 to be flat, the bent region 10b formed on the battery cell 10 is opposite to the third pressing surface 313. The third pressing surface 313 may apply pressure to the bending region 10b of the battery cell 10 and heat the bending region 10 b.

In some embodiments, the inside heating pin 31 thermally compounds the winding start section 10a of the battery cell 10 through the first abutting surface 311, the second abutting surface 312, and the third abutting surface 313.

In some embodiments, referring to fig. 5 and 7, the blanking assembly 30 further includes an outer clamp pin 32. The outer clip 32 is configured to clip the winding start section 10a together with the third abutting surface 313 and apply a predetermined pressure to the winding start section 10 a. After the battery cell 10 is wound on the winding pin 20, the inside heating pin 31 and the outside pinching pin 32 may pinch a predetermined region of the battery cell 10 from the inside and the outside of the battery cell 10, respectively. The battery cell 10 is constrained by the inner heating needle 31 and the outer clamping needle 32, so that the first pole piece 11, the second pole piece 12 and the diaphragm 13 are not in slip dislocation with each other. The inner heating needle 31 and the outer clamping needle 32 stretch the battery cell 10 to be flat, and then the inner heating needle 31 heats the battery cell 10 to enable at least one of the first pole piece 11 and the second pole piece 12 of the winding starting section 10a to successfully complete thermal compounding with the diaphragm 13 and ensure stable and reliable connection state. Illustratively, the outside clamp pin 32 is itself cylindrical.

In some embodiments, referring to fig. 8, the inside heating pin 31 includes a body 31a and an anti-sticking layer 31 b. At least part of the outer surface of the body 31a is covered with an anti-sticking layer 31 b. The release layer 31b is configured to abut the winding start section 10 a. After the inner heating needle 31 finishes heating the winding start section 10a of the battery cell 10, the anti-sticking layer 31b of the inner heating needle 31 has an anti-sticking effect, so that the inner heating needle 31 is not easily stuck to the molten region of the separator 13, and the possibility that the inner heating needle 31 is difficult to pull out due to the sticking of the inner heating needle 31 to the winding start section 10a or the winding start section 10a is pulled during pulling out is reduced. Illustratively, the release layer 31b is formed by applying a release material on the body 31a using a coating process. Illustratively, the material of the release layer 31b may be a release material such as teflon.

In some embodiments, referring to fig. 9, the inside heating pin 31 includes a body 31a and a heater 31 c. The body 31a is configured to press against the winding start section 10 a. The heater 31c is configured to heat the body 31 a. The winding start section 10a of the battery cell 10 is thermally compounded by the body 31 a. The heater 31c may heat the body 31a to a predetermined temperature and then indirectly heat the winding start section 10a of the battery cell 10 through the body 31 a. Since the inner heating pin 31 needs to have good bending resistance, the bending resistance of the entire inner heating pin 31 can be satisfied by increasing the rigidity of the body 31a itself, and the bending resistance of the entire inner heating pin 31 can be satisfied without the rigidity of the heater 31c itself, so that the structural strength requirement of the heater 31c itself is reduced, and the manufacturing difficulty of the heater 31c is reduced.

In some examples, referring to fig. 9, the body 31a is a hollow structure. The body 31a has an inner accommodation space. At least a part of the heater 31c is accommodated inside the body 31 a. The body 31a may cover the heater 31c in a circumferential direction of the heater 31c to protect the heater 31c and reduce the possibility of damage to the heater 31 c. The heater 31c is disposed inside the body 31a, so that the heater 31c can easily keep the heating state of each region of the body 31a consistent, thereby ensuring that the temperature rise of each region of the body 31a is consistent, which is beneficial to reducing the possibility that the heating effect of the separator 13 of the battery cell 10 is different due to the uneven temperature of the region where the body 31a contacts the battery cell 10, and further reducing the possibility that the adhesion firmness degree of at least one of the first pole piece 11 and the second pole piece 12 is different from that of the separator 13 in the heating region.

In some examples, the heater 31c is disposed outside the body 31 a. The body 31a may be a solid rod, and the heater 31c is provided at one end of the body 31a and heats the body 31a through the end.

In some examples, referring to fig. 9, the inside heating pin 31 further includes a temperature sensor 31 d. The temperature sensor 31d is configured to monitor the temperature of the body 31 a. The temperature at which the membrane 13 melts needs to be controlled at a predetermined temperature to achieve good thermal compounding. If the temperature is too high, the separator 13 may be damaged by burning. If the temperature is too low, there is a possibility that the separator 13 cannot be brought into a molten state to cause thermal recombination failure. The temperature of the body 31a can be monitored in real time through the temperature sensor 31d, whether the temperature of the body 31a is at the preset temperature or not is convenient to judge, and the possibility that the thermal compound effect is poor due to the fact that the temperature of the body 31a is higher or lower is reduced. The heater 31c can be started or stopped in real time through the temperature signal acquired by the temperature sensor 31d, so that the temperature of the body 31a is always kept at the preset heating temperature, the consistency of the heat recombination effect can be ensured, and the heat recombination efficiency can be improved. Illustratively, the body 31a is a hollow structure, and the temperature sensor 31d may be disposed inside the body 31 a.

Referring to fig. 10, an embodiment of the present application further provides a method for manufacturing a battery cell 10, which includes:

manufacturing an electric core 10;

the winding start section 10a of the battery cell 10 is heated to thermally compound at least one of the first pole piece 11 and the second pole piece 12 of the winding start section 10a with the separator 13.

In some embodiments, the first pole piece 11, the second pole piece 12, and the separator 13 are wound to form the cell 10. The battery cell 10 may be the battery cell 10 of the above-described embodiment. The wound battery cell 10 is stretched into a flat shape. The winding start section 10a of the battery cell 10 is heated. Then, the flat battery cell 10 is subjected to a pre-press molding.

The method for manufacturing the battery cell 10 according to the embodiment of the present application is used to manufacture the battery cell 10 according to the embodiment described above. In the method for manufacturing the battery cell 10 according to the embodiment of the present application, the first pole piece 11, the second pole piece 12, and the separator 13 are wound to form the battery cell 10, and then the battery cell 10 is stretched to be flat. The winding start section 10a is heated to thermally compound at least one of the first and

second pole pieces

11, 12 with the separator 13 so that the separator 13 is no longer in a free state, but is constrained by the first and/or

second pole pieces

11, 12. Because the diaphragm 13 at the inner ring part is restrained, the diaphragm 13 at the inner ring part is not easy to retract, so that the possibility that the positive plate and the negative plate at the inner ring part have overlarge gaps due to the fact that the positive plate and the negative plate are driven to move inwards due to the retraction of the diaphragm 13 is reduced, and the possibility of the problem of lithium precipitation is further reduced.

In some embodiments, the method for manufacturing the battery cell 10 further includes: along vertical direction Y, support from the both sides of electric core 10 and press electric core 10 to increase the flat degree of electric core 10, make electric core 10 reach predetermined flat degree, satisfy the product requirement.

In some embodiments, in the step of heating the winding start section 10a of the battery cell 10 to thermally compound at least one of the first pole piece 11 and the second pole piece 12 of the winding start section 10a with the separator 13, the heating time is 2 seconds to 5 seconds. When the heating time is less than 2 seconds, there is a possibility that the heating time is short and the degree of melting of the separator 13 does not meet a predetermined requirement, thereby causing poor thermal recombination effect or thermal recombination failure. If the heating time is longer than 5 seconds, the heating time may be long, and the degree of melting of the separator 13 may exceed a predetermined level, which may cause breakage of the separator 13 and failure of the separator 13.

In some embodiments, in the step of heating the winding start section 10a of the battery cell 10 to thermally compound at least one of the first pole piece 11 and the second pole piece 12 of the winding start section 10a with the separator 13, the heating temperature is 85 to 95 degrees. When the heating temperature is lower than 85 degrees, there is a possibility that the heating temperature is low and the degree of melting of the separator 13 does not meet a predetermined requirement, thereby causing poor thermal recombination effect or failure of thermal recombination. When the heating temperature is higher than 95 degrees, the heating temperature is high, and the degree of melting of the separator 13 exceeds a predetermined level, and the separator 13 may be broken and the separator 13 may fail.

In some embodiments, in the step of heating the winding start section 10a of the battery cell 10 to thermally compound at least one of the first pole piece 11 and the second pole piece 12 of the winding start section 10a with the separator 13, a compressive stress of 3 megapascals (MPa) or more and 10 megapascals or less is applied to a heating region of the winding start section 10 a. When the compressive stress applied to the heating region of the winding start section 10a is less than 3 mpa, the extrusion force applied to at least one of the first pole piece 11 and the second pole piece 12 and the diaphragm 13 does not meet the predetermined pressure requirement, so that the adhesion firmness of the molten part of at least one of the first pole piece 11 and the second pole piece 12 and the diaphragm 13 does not meet the predetermined requirement, and further, the separation of at least one of the first pole piece 11 and the second pole piece 12 and the diaphragm 13 is likely to occur again after the thermal compounding is completed. When the compressive stress applied to the heating region of the winding start section 10a is greater than 10 mpa, on one hand, the applied compressive force exceeds the predetermined pressure requirement, which may cause at least one of the first pole piece 11, the second pole piece 12 and the separator 13 to be subjected to an excessive force, thereby causing structural damage, and on the other hand, the requirement on the bending resistance of the component applying pressure to the battery cell 10 is high, which increases the difficulty in manufacturing and using the component. The means for applying pressure may be the inside heating pins 31 of the above-described embodiments. Illustratively, in the thermal compounding step, a compressive stress of 7 mpa is applied to the heating region of the winding start section 10 a.

While the present application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the present application, and in particular, features shown in the various embodiments may be combined in any manner as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein but is to cover all embodiments that may fall within the scope of the appended claims.

Claims

1. A cell manufacturing apparatus for manufacturing a cell, the cell including a first pole piece, a second pole piece, and a separator, the cell having a winding start section located inside, the cell manufacturing apparatus comprising:

a winding needle configured to wind the first pole piece, the second pole piece, and the separator to form the cell;

a blanking assembly configured to remove the electrical core from the winding needle, the blanking assembly including an inside heating needle configured to press against and heat the winding start section to thermally compound at least one of the first and second pole pieces of the winding start section with the separator.

2. The apparatus of claim 1, wherein the inside heating pin comprises a first abutting surface and a second abutting surface which are oppositely arranged in a vertical direction, at least one of the first abutting surface and the second abutting surface is a horizontal surface, and the inside heating pin thermally recombines the winding start section of the battery cell through at least one of the first abutting surface and the second abutting surface.

3. The cell manufacturing apparatus of claim 2, wherein an orthographic projection of at least one of the first abutting surface and the second abutting surface in the vertical direction has a width smaller than an orthographic projection of the inside heating pin in the vertical direction, and the width is a dimension measured in a direction perpendicular to an axial direction of the cell.

4. The cell manufacturing apparatus of claim 2 or 3, further comprising a first pressing plate and a second pressing plate configured to press the cell from both sides of the cell, respectively, in the vertical direction.

5. The battery cell manufacturing apparatus according to claim 1, wherein the inside heating pin includes a third abutting surface, and a first abutting surface and a second abutting surface that are disposed opposite to each other in a vertical direction, the third abutting surface connects the first abutting surface and the second abutting surface, the third abutting surface is an arc-shaped surface, and the inside heating pin thermally recombines the winding start section of the battery cell through the third abutting surface.

6. The battery cell manufacturing apparatus according to claim 5, wherein the blanking assembly further comprises an outer clamping pin configured to clamp the winding start section with the third pressing surface.

7. The cell manufacturing apparatus of claim 1, wherein the inside heating pin comprises a body and a release layer, at least a portion of an outer surface of the body covering the release layer, the release layer configured to abut the winding initiation segment.

8. The cell manufacturing apparatus of claim 1, wherein the inside heater pin includes a body configured to press against the winding start section and a heater configured to heat the body to thermally compound the winding start section of the cell with the body.

9. The cell manufacturing apparatus of claim 8, wherein the body is a hollow structure, and at least a portion of the heater is housed inside the body.

10. The cell manufacturing apparatus of claim 8, wherein the inside heater pin further comprises a temperature sensor configured to monitor a temperature of the body.

11. A method of manufacturing a cell, comprising:

manufacturing a battery cell;

heating a winding start section of the cell to thermally compound at least one of a first pole piece and a second pole piece of the winding start section with a diaphragm.

12. The cell manufacturing method of claim 11, further comprising: and along the vertical direction, the battery cell is pressed against the two sides of the battery cell.

13. The cell manufacturing method of claim 11, wherein in the step of heating the winding start section of the cell to thermally compound at least one of the first pole piece and the second pole piece of the winding start section with the separator, the heating time is 2 seconds to 5 seconds; and/or the heating temperature is 85 to 95 degrees.

14. The cell manufacturing method of claim 11, wherein in the step of heating the winding start section of the cell to thermally compound at least one of the first pole piece and the second pole piece of the winding start section with the separator, a compressive stress greater than or equal to 3 mpa and less than or equal to 10 mpa is applied to the winding start section heating region.