Preparation method and manufacturing equipment of pole piece and preparation method and preparation equipment of roll core

Abstract

The invention discloses a preparation method and manufacturing equipment of a pole piece and a preparation method and preparation equipment of a roll core. The preparation method of the pole piece comprises the following steps: S1, providing a substrate; s2, an active layer is coated on the base body through a coating mechanism, a material belt is formed, the material belt at least comprises a pole piece active substance coating area in the length direction and the width direction, and the pole piece is provided with a head section, a middle section and a tail section which are sequentially connected in the length direction; the pole piece active material coating area is provided with a corresponding active material coating area head section, an active material coating area middle section and an active material coating area tail section; s3, cutting the material belt by a cutting mechanism to form a pole piece, wherein the effective width of at least part of the active layer of the head section and / or the tail section of the pole piece is different from the effective width of at least part of the active layer of the middle section of the pole piece; the manufacturing method mainly solves the problem of how to manufacture the roll core which can still ensure that the anode active layer completely covers the cathode active layer even if the head and tail shaking phenomenon occurs.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a method and equipment for preparing a pole piece, and a method and equipment for preparing a winding core. Background Art

[0002] The cells in the current battery are divided into a laminated structure or a wound structure, wherein the laminated structure cells are stacked in the order of anode sheet, separator, cathode sheet, separator, anode sheet..., wherein the wound structure cells are stacked by anode sheet, separator and cathode sheet first and then wound, wherein the anode sheet is also called the negative electrode sheet in this field, and the cathode sheet is also called the positive electrode sheet in this field, wherein the separator plays the role of separating the anode sheet and the cathode sheet to avoid the contact between the anode sheet and the cathode sheet and causing a short circuit inside the battery, and the outer dimensions of the separator are usually designed to be larger than the outer dimensions of the anode sheet and the outer dimensions of the cathode sheet to ensure that the anode sheet and the cathode sheet will not contact each other. Specifically, during the charge and discharge process of the cell, ions will pass through the separator under the action of the electrolyte and move between the anode sheet and the cathode sheet, that is, the ions will be embedded or de-embedded back and forth on the two electrodes.

[0003] The anode active layer in the anode sheet usually adopts OH (overhang) design. Specifically, the so-called OH design is as follows: Figure 1 As shown, after the anode sheet and the cathode sheet are stacked together through the separator, the anode active layer ( Figure 1 The cathode active layer (shown in dark grey) needs to completely cover the cathode sheet. Figure 1 In other words, when the anode sheet and the cathode sheet are stacked, the anode active layer on the anode sheet will protrude relative to the cathode active layer on the cathode sheet in the width direction, that is, the area of ​​the anode active layer on the anode sheet is larger than the area of ​​the cathode active layer on the cathode sheet, so that the anode active layer on the anode sheet completely covers the cathode active layer on the cathode sheet, thereby ensuring that the ions precipitated from the cathode sheet can be embedded in the anode after passing through the diaphragm, and ensuring that the ions precipitated from the cathode sheet will not be scattered to the area outside the anode sheet, so as to ensure the safety of the battery cell.

[0004] See also Figure 2 When the battery cell adopts a winding structure, there will be two free sections after the battery cell is wound, one of which is wound at the innermost head end, and the other is wound at the outermost end. Since the two free sections have a certain degree of freedom, the anode sheet and / or cathode sheet at the two free sections are prone to offset and misalignment during the winding process (also known as the head and tail swinging problem in this field), especially the terminal free section. During the actual winding process of the battery cell, the terminal free section is more likely to have the problem of relative misalignment of the anode sheet and the cathode sheet under the action of the winding traction tension, resulting in the terminal anode active layer ( Figure 2 The cathode active layer at the end (indicated by dark gray) cannot be completely covered Figure 2 The ions precipitated from the cathode sheet will be scattered to the area outside the anode sheet, which will have a great impact on the safety of the battery cell.

[0005] Therefore, it is necessary to improve the existing technology. Summary of the invention

[0006] The present invention provides a method and equipment for preparing a pole piece, and a method and equipment for preparing a winding core, which mainly solve the technical problem of how to manufacture a winding core that can ensure that the anode active layer can completely cover the cathode active layer even if a certain degree of head and tail swinging occurs.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing a pole piece comprises the following steps:

[0009] S1: providing a substrate;

[0010] S2: The coating mechanism coats the active layer on the substrate to form a material strip, wherein the material strip includes at least one pole piece active material coating area in the length and width directions, wherein the pole piece has a first section, a middle section and a tail section connected in sequence in the length direction, and the pole piece active material coating area has a corresponding active material coating area first section, an active material coating area middle section and an active material coating area tail section;

[0011] S3: The cutting mechanism cuts the material strip to form the pole piece, and the effective width of at least part of the active layer of the first section and / or the last section of the pole piece is different from the effective width of at least part of the active layer of the middle section of the pole piece.

[0012] In one of the technical solutions, in step S3: the cutting mechanism has a first cutting path and a second cutting path with different cutting widths for the material strip; the cutting mechanism cuts according to the first cutting path to obtain the first section and / or the tail section of the pole piece; the cutting mechanism cuts according to the second cutting path to obtain the middle section of the pole piece, and the middle section of the pole piece at least partially has a plurality of pole ear portions spaced apart in the width direction, and the pole ear portion at least includes a portion of the uncoated area of ​​the active material.

[0013] In one of the technical solutions, the active layer is a cathode active layer, the cutting width of the second cutting path is smaller than the cutting width of the first cutting path, and the cutting mechanism cuts the cathode active layer area when cutting according to the first cutting path.

[0014] In one of the technical solutions, when the cutting mechanism cuts according to the first cutting path, the width of the cathode active layer cut by the first cutting path is 0.3 mm-0.7 mm.

[0015] In one of the technical solutions, when the cutting mechanism cuts according to the second cutting path, the cathode active layer is not cut.

[0016] In one of the technical solutions, the active layer is a cathode active layer, and when the cutting mechanism cuts according to the second cutting path, the cathode active layer region is cut.

[0017] In one of the technical solutions, the width of the cathode active layer cut by the second cutting path is 0.1-0.2 mm.

[0018] In one of the technical solutions, in step S2, an insulating layer is also coated on the substrate, the insulating layer and the active layer are arranged on the same surface of the substrate, and the insulating layer is arranged on one side or both sides where multiple cathode ears need to be cut.

[0019] In one of the technical solutions, the active layer is an anode active layer, the cutting width of the second cutting path is greater than the cutting width of the first cutting path, and the cutting mechanism cuts the anode active layer area when cutting according to the second cutting path.

[0020] In one of the technical solutions, when the cutting mechanism cuts according to the second cutting path, the width of the anode active layer cut by the second cutting path is 0.3-0.7 mm.

[0021] In one of the technical solutions, when the cutting mechanism cuts according to the first cutting path, the anode active layer area is not cut.

[0022] In one of the technical solutions, when the cutting mechanism cuts according to the first cutting path, the anode active layer area is cut.

[0023] In one of the technical solutions, the width of the anode active layer cut by the first cutting path is 0.1-0.2 mm.

[0024] In one of the technical solutions, in step S2, an insulating layer is further coated on the substrate, the insulating layer and the active layer are arranged on the same surface of the substrate, the active layer is a cathode active layer, and the coating width of at least part of the cathode active layer on the middle section of the active material coating area of ​​the pole piece is greater than the coating width of at least part of the cathode active layer on the first section and / or the tail section of the active material coating area of ​​the pole piece;

[0025] In step S3, after cutting, the width of at least a portion of the cathode active layer at the beginning and / or the end of the pole piece is smaller than the width of at least a portion of the cathode active layer at the middle section of the pole piece.

[0026] In one of the technical solutions, in step S3, the electrode piece is cut by the cutting mechanism to form a cathode ear on one side in the width direction;

[0027] In the step S2, the insulating layer is disposed on the side where the cathode ear portion needs to be cut out.

[0028] In one of the technical solutions, in step S2, after coating the insulating layer and the cathode active layer, the width of at least part of the cathode active layer coating in the middle section of the pole piece active material coating area is 0.3-2 mm larger than the width of at least part of the cathode active layer coating in the first section and / or the tail section of the pole piece active material coating area.

[0029] In one of the technical solutions, in step S2, the active layer is an anode active layer, and the width of at least part of the anode active layer coating in the middle section of the pole piece active material coating area is smaller than the width of at least part of the anode active layer coating in the first section and / or the tail section of the pole piece active material coating area.

[0030] In step S3, after cutting, the width of at least part of the anode active layer of the first section and / or the last section of the pole piece is greater than the width of at least part of the anode active layer of the middle section of the pole piece.

[0031] In one of the technical solutions, in step S2, the width of at least part of the anode active layer coating in the middle section of the pole piece active material coating area is 0.3-2 mm smaller than the width of at least part of the anode active layer coating in the first section and / or the last section of the pole piece active material coating area.

[0032] In one of the technical solutions, in step S2, the coating mechanism has a first covering width and a second covering width with different covering widths for the active layer;

[0033] The coating mechanism coats the insulating layer of the first covering width on at least one side of the middle section of the active material coating area in the width direction, and the coating mechanism coats the insulating layer of the second covering width on at least one side of the first section and / or the last section of the active material coating area in the width direction.

[0034] In one of the technical solutions, in step S2, the active layer is a cathode active layer, the second covering width is greater than 0, the first covering width is greater than or equal to 0, and the second covering width is greater than the first covering width.

[0035] In step S3, after cutting, at least part of the cathode active layer of the electrode sheet in the first section or the last section is covered by the insulating layer.

[0036] In one of the technical solutions, in step S2, the active layer is an anode active layer, the second covering width is greater than or equal to 0, the first covering width is greater than 0, and the second covering width is less than the first covering width,

[0037] In step S3, after cutting, at least part of the anode active layer of the pole piece in the middle section is covered by the insulating layer.

[0038] The present application also provides a method for preparing a core, comprising the following steps:

[0039] Providing an anode sheet, a cathode sheet and a separator, wherein at least one of the anode sheet and the cathode sheet is prepared by the above-mentioned method for preparing the electrode sheet;

[0040] The anode sheet, the separator and the cathode sheet are stacked and wound into a winding core, the anode sheet first section and / or the cathode sheet first section are located at the initial end of the winding core, and the anode sheet tail section and / or the cathode sheet tail section are located at the tail end of the winding core.

[0041] In one of the technical solutions, the effective width value of at least part of the active layer in the middle section of the anode sheet is set to A, the effective width value of at least part of the active layer in the first section and / or the last section of the anode sheet is set to B, the effective width value of at least part of the active layer in the middle section of the cathode sheet is set to C, the effective width value of at least part of the active layer in the first section and / or the last section of the cathode sheet is set to D, d0=AC, d=BD, and d is greater than d0.

[0042] In one of the technical solutions, d0 is 1.9-3.5 mm, d is 2.2-4.2 mm, and d-d0 is 0.3-2.3 mm.

[0043] In one of the technical solutions, d0 is 1.9-3.5 mm, d is 2.5-4.9 mm, and d-d0 is 0.6-3 mm.

[0044] In one of the technical solutions, let the free length of the free section be L, △d=d-d0=(BD)-(AC), and △d≥0.5L 2 +0.5L+0.2, where L is 0.1m-0.5m and △d is 0.3-0.7mm.

[0045] In one of the technical solutions, when A and B are equal, the △d is the difference of (CD), and the (CD) ≥ 0.5L 2 +0.5L+0.2.

[0046] In one of the technical solutions, when C and D are equal, the △d is the difference between (BA), and the (BA) ≥ 0.5L 2 +0.5L+0.2.

[0047] The present application also provides a pole piece manufacturing device, which applies any of the pole piece preparation methods described above.

[0048] The present application also provides a winding core preparation device, including a winding machine, for winding the anode sheet, the separator and the anode sheet that have been stacked in sequence into a winding core.

[0049] Compared with the prior art, the method for preparing the pole piece provided by the present invention has at least the following beneficial effects:

[0050] In the process of manufacturing the core, for the middle section of the core, the corresponding active layer can be coated on the anode sheet and the cathode sheet according to the existing width difference of d0. For example, in the middle section, the coverage width A of the anode active layer is originally designed to be 1.2 times the coverage width C of the cathode active layer; but for the free section (i.e., the first section or the last section of the electrode sheet), the preparation method reduces the D value to make d greater than d0; or / and, the preparation method increases the B value to make d greater than d0, thereby ensuring that even if the anode sheet or the cathode sheet at the free section has a certain degree of head and tail swinging problem, it can also ensure that the anode active layer at the free section can still completely cover the cathode active layer, thereby improving the stability and safety of the core during the charging and discharging process and is conducive to extending the service life of the core, so as to meet the design requirements of high safety and high service life of batteries in the automotive field. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 A schematic diagram of the structure of a positive electrode sheet (cathode sheet) and a negative electrode sheet (anode sheet) in a winding core provided by the prior art of the present application when they are stacked on each other in an ideal state;

[0053] Figure 2 A schematic diagram of the structure of a positive electrode sheet (cathode sheet) and a negative electrode sheet (anode sheet) in a winding core provided by the prior art of the present application when they are superimposed on each other in actual situations and the problem of head and tail swinging occurs;

[0054] Figure 3A schematic diagram of the structures of three cathode sheets and two anode sheets provided in Example 1 of the present application;

[0055] Figure 4 A schematic diagram of the structure of a battery cell provided in Example 1 of the present application;

[0056] Figure 5 A schematic diagram of the structure of a battery provided in Example 1 of the present application;

[0057] Figure 6 A schematic diagram of the structure of a small section of a material strip for making a cathode sheet provided in Example 2 of the present application, with multiple cathode ears cut out on both sides in the width direction;

[0058] Figure 7 A schematic diagram of the structure of a small section of a material strip for making an anode sheet provided in Example 2 of the present application, with multiple anode ears cut out on both sides in the width direction;

[0059] Figure 8 A schematic diagram of the structure of a small section of a material strip for making a cathode sheet provided in Example 2 of the present application, both sides of which in the width direction are coated with an insulating layer and a plurality of cathode ears are cut out;

[0060] Fig. 9 A flow chart of a method for manufacturing a first pole piece provided in Embodiment 2 of the present application;

[0061] Fig.10 A flow chart of a method for manufacturing a second pole piece provided in Embodiment 2 of the present application;

[0062] Fig.11 A schematic diagram of the structure of a pole piece manufacturing device provided in the fourth embodiment of the present application;

[0063] Fig.12 for Fig.11 The structure diagram of a pole piece manufacturing device in the area where the slitting knife position is set is shown;

[0064] Fig.13 for Fig.11 The structure diagram of a pole piece manufacturing device in the area where a coating mechanism is set is shown;

[0065] Fig.14 for Fig.13 A side view of the structure shown;

[0066] Fig.15 This is a schematic structural diagram of a core preparation device at the winding needle position provided in Example 5 of the present application.

[0067] Reference numerals:

[0068] 11. Anode sheet body; 12. Anode active layer; 13. Anode ear; 21. Cathode sheet body; 22. Cathode active layer; 23. Cathode ear; 3. Insulating layer; 4. Outer film; 5. Positive electrode ear; 6. Negative electrode ear; 7. Outer shell; 71. Shell; 72. Top cover; 721. Pole; 8. Cell; 10. Middle section; 20. Free section;

[0069] 100, laser; 200, roller; 300, material strip; 301, material section; 400, slitting knife; 500, coating mechanism; 501, coating liquid; 600, foil substrate; 700, active layer; 800, winding needle. DETAILED DESCRIPTION

[0070] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0071] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0072] It should be understood that the orientations or positional relationships indicated by terms such as "upper", "lower", "top", "bottom", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0074] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0075] Embodiment 1

[0076] See also Figure 3The embodiment of the present invention provides a winding core, which includes an anode sheet, a separator and a cathode sheet. The anode sheet, the separator and the cathode sheet are stacked and wound in sequence to form the winding core. The separator is used to separate the anode sheet and the cathode sheet to prevent the anode sheet and the cathode sheet from directly contacting each other and causing an internal short circuit in the winding core. The anode sheet includes an anode sheet body 11 and an anode active layer 12 coated on the anode sheet body 11. The anode sheet body 11 is used to carry the anode active layer 12. When the anode sheet and the separator are stacked on each other, the side of the anode sheet coated with the anode active layer 12 needs to face the separator. Figure 3 The light grey part in the “first anode sheet” and the “second anode sheet” represents the anode sheet main body 11, wherein the anode sheet main body 11 can be selected as copper foil, or in order to increase the conductivity of the anode sheet, the anode sheet main body 11 can also be selected as copper foil coated with a conductive carbon layer, or in order to increase the bonding force, the anode sheet main body 11 can also be selected as copper foil coated with an adhesive layer. Figure 3 The black part in the "first anode sheet" and "second anode sheet" represents the anode active layer 12. The cathode sheet includes a cathode sheet body 21 and a cathode active layer 22 coated on the cathode sheet body 21. The cathode sheet body 21 is used to carry the cathode active layer 22. The cathode sheet body 21 can be selected as aluminum foil, or in order to increase the conductivity of the cathode sheet, the cathode sheet body 21 can also be selected as aluminum foil coated with a conductive layer, or in order to increase the bonding force, the cathode sheet body 21 can also be selected as aluminum foil coated with an adhesive layer. When the cathode sheet is stacked with the diaphragm, the side of the cathode sheet coated with the cathode active layer 22 needs to face the diaphragm. Figure 3 The light grey portion in the “first cathode sheet”, “second cathode sheet” and “third cathode sheet” represents the cathode sheet main body 21. Figure 3 The black part in the "first cathode sheet", "second cathode sheet" and "third cathode sheet" represents the cathode active layer 22. The design requirement of the winding core is that the anode active layer 12 needs to be larger than the cathode active layer 22 in both the length direction (ie, X direction) and the width direction (ie, Y direction) so that the anode active layer 12 can completely cover the cathode active layer 22.

[0077] Please refer again Figure 3In the winding process, a single electrode sheet can be divided into a first section, a middle section 10 and a tail section which are connected in sequence in the length direction (that is, the conveying direction of the electrode sheet in the winding process), wherein, after the anode sheet, the separator and the cathode sheet are wound and cut, the first section is wound at the innermost part and the tail section is wound at the outermost part. The first section and the tail section are prone to swinging due to a certain degree of freedom after winding and cutting. Therefore, the first section and the tail section of the electrode sheet can be called free sections 20. The two free sections 20 are equivalent to being arranged at the two ends of the middle section 10 in the length direction. The attached figure takes the free segment 20 on the left as the first segment and the free segment 20 on the right as the tail segment as an example. After the winding core is wound, the two free segments 20 have a certain degree of freedom, so the anode sheet or the cathode sheet is more likely to have the problem of head and tail swinging, resulting in the anode active layer 12 not completely covering the cathode active layer 22 in the end area of ​​the free segment 20. In particular, the free segment 20 located at the tail segment is more likely to have the problem of head and tail swinging due to the larger radius after winding and the larger degree of freedom. In this regard, the present embodiment adopts the following technical means to solve this technical problem:

[0078] like Figure 3 As shown, let the effective width value of the anode active layer 12 in the middle section 10 be A, let the effective width value of the anode active layer 12 in the free section 20 be B, let the effective width value of the cathode active layer 22 in the middle section 10 be C, let the effective width value of the cathode active layer 22 in the free section 20 be D, let d0=AC, let d=BD, wherein d0 and d are both greater than 0, and d of at least one free section 20 is greater than d0. Specifically, when designing the winding core, for the middle section 10 of the winding core, the conventional design of d0 can be followed, for example, A is conventionally designed to be 1.2 times of C, but for the free section 20 of the winding core, the present solution designs the d value to be greater than d0, thereby ensuring that even if the anode sheet or cathode sheet at the free section 20 has a certain degree of head and tail swinging problem, it can also ensure that the anode active layer 12 at the free section 20 can still completely cover the cathode active layer 22, thereby improving the stability and safety of the winding core during the charging and discharging process and facilitating the extension of the service life of the winding core, so as to meet the design requirements of high safety and high service life for battery applications in the automotive field. Optionally, the effective width value of part of the middle section 10 can be A, or the effective width value of all the middle sections 10 can be A; similarly, the above settings also apply to B, C, and D, which can be the effective width value of part of the section or the effective width value of the whole section. If the electrode is cut by cutting, the effective width of the active layer is the width of the active layer remaining on the electrode coating area after cutting; if the method of coating and covering part of the active layer with an insulating layer 3 (preferably TF8) is used, the effective width of the active layer only refers to the width of the active layer not covered by the insulating layer 3 (preferably TF8), and the active layer covered by the insulating layer 3 (preferably TF8) is not counted as the effective width.

[0079] In this embodiment, the two free segments 20 of the winding core can be designed to have d greater than d0. In other embodiments, one of the first free segment 20 or the last free segment 20 of the winding core can also be designed to have d greater than d0.

[0080] Please refer again Figure 3 In order to achieve that d is greater than d0, this embodiment provides the following three technical solutions:

[0081] The first technical solution: A and B can be equal, and D is designed to be smaller than C, so that d is greater than d0. That is, the winding core of this solution is equivalent to using Figure 3 The "second anode sheet" and "second cathode sheet" in the embodiment of the present invention are equivalent to the winding core of the present invention. Figure 3 The "second anode sheet" and "third cathode sheet" in ;

[0082] The second technical solution: B is designed to be greater than A, and C is designed to be equal to D, so that d is greater than d0. That is, the winding core of this solution is equivalent to using Figure 3 The "first anode sheet" and "first cathode sheet" in the invention;

[0083] The third technical solution: B is designed to be larger than A, and D is designed to be smaller than C, so that d is greater than d0. That is, the winding core of this solution is equivalent to using Figure 3 The "first anode sheet" and "second cathode sheet" in the embodiment of the present invention are equivalent to the winding core of the present invention. Figure 3 The “first type of anode sheet” and the “third type of cathode sheet”.

[0084] In the first and second technical solutions, d0 is optionally 1.9-3.5 mm, d is 2.2-4.2 mm, and d-d0 is 0.3-2.3 mm. In the third technical solution, d0 is optionally 1.9-3.5 mm, d is 2.5-4.9 mm, and d-d0 is 0.6-3 mm.

[0085] Please refer again Figure 3 Optionally, the cathode sheet body 21 is cut so that the cathode sheet body 21 has a width direction (i.e. Figure 3 The Y direction in the middle) is connected to one side with multiple Figure 3 The cathode ears 23 are arranged at intervals in the X direction in the anode sheet body 11, and the anode sheet body 11 is cut so that one side of the anode sheet body 11 in the width direction is connected with a plurality of cathode ears 23 arranged in the length direction (i.e. Figure 3When the anode sheets, separators and cathode sheets are stacked and wound into a wound structure, all cathode ears 23 need to be assembled and welded together to form the positive electrode ears 5, and all anode ears 13 also need to be assembled and welded together to form the negative electrode ears 6. By providing a plurality of cathode ears 23 and a plurality of anode ears 13, the active material inside the roll core can be charged or discharged at various positions at the same time, so that the charging or discharging performance of the roll core is fully exerted.

[0086] In another embodiment, the cathode sheet body 21 is cut so that the cathode sheet body 21 has a width direction (i.e. Figure 3 Both sides of the Y direction are connected with multiple Figure 3 The cathode ears 23 are arranged at intervals in the X direction; the anode sheet body 11 is cut so that the anode sheet body 11 is in the width direction (ie Figure 3 Both sides of the Y direction are connected with multiple Figure 3 Anode ears 13 are arranged at intervals (in the X direction).

[0087] Further optionally, the present solution further coats the root of the cathode ear 23 of the cathode sheet with an insulating layer 3, and the insulating layer 3 and the cathode active layer 22 are arranged on the same surface of the cathode sheet body 21. Figure 3 The dark gray part in the "first cathode sheet", "second cathode sheet" and "third cathode sheet" represents the insulating layer 3. The insulating layer 3 plays the role of strengthening the root of the cathode ear 23 to prevent the cathode ear 23 of the cathode sheet from being too soft and easy to fold and break. The insulating layer 3 also plays the role of preventing the burrs on the anode sheet from piercing the cathode sheet, reducing the risk of internal short circuit of the winding core and improving the safety of the winding core. The insulating layer 3 can be selected as TF8 (a kind of thermal conductive silicone grease). The thermal conductivity coefficient of TF8 is 12.5W / mK. TF8 has good heat dissipation performance and can more effectively transfer the heat generated by the winding core to the outside. In addition, TF8 has good stability and can maintain stable heat dissipation performance in high temperature environment.

[0088] In other embodiments, there may be no ear portions on the anode sheet main body 11 and the cathode sheet main body 21, that is, the anode sheet main body 11 and the cathode sheet main body 21 may be square rectangular structures, and the external positive ear may be connected to the cathode sheet main body 21 at multiple positions in the length direction through multiple connecting sheets, and the external negative ear may also be connected to the anode sheet main body 11 at multiple positions in the length direction through multiple connecting sheets. In this case, the purpose of simultaneously charging or discharging the active materials in the core roll at various positions to give full play to the charging or discharging performance of the core roll can also be achieved.

[0089] Depend on Figure 3It can be seen that both the “second cathode sheet” and the “third cathode sheet” are designed with D less than C. In order to achieve D less than C, this embodiment provides the following three manufacturing methods:

[0090] Manufacturing method one: The anode sheet or cathode sheet is cut from a material strip, and the surface of the material strip is coated with an anode active layer or a cathode active layer before cutting. After the material strip is cut, multiple pole ears are cut out on at least one side of the electrode sheet in the width direction (i.e., the Y direction), and the amount of active layer cut in the width direction of at least one of the first and last sections of the electrode sheet is different from the amount of active layer cut in the width direction of the middle section of the electrode sheet. It can be specifically understood that for the cathode sheet, at the first or last section, by cutting the cathode sheet body 21 along the Y direction, a portion of the cathode active layer 22 is also cut, so that the remaining effective coating width value of the cathode active layer 22 at the first or last section is reduced from the original C value to the D value, thereby forming Figure 3 The structure of the "second cathode sheet" shown; for the anode sheet, at the middle section 10, by cutting the anode sheet body 11 along the Y direction and also cutting part of the anode active layer 12, the remaining effective coating width value of the anode active layer 12 at the middle section 10 is reduced from the original B value to the A value.

[0091] Manufacturing method one of the above section is further explained. In one of the schemes, the active layer cutting amount in the width direction of the first and last sections of the electrode sheet may be different from the active layer cutting amount in the width direction of the middle section of the electrode sheet, that is, for the anode sheet, the cutting amount of the anode active layer in the width direction of the first and last sections of the anode sheet may be smaller than the cutting amount of the anode active layer in the width direction of the middle section of the anode sheet; for the cathode sheet, the cutting amount of the cathode active layer in the width direction of the first and last sections of the cathode sheet may be larger than the cutting amount of the cathode active layer in the width direction of the middle section of the cathode sheet.

[0092] Manufacturing method 2: By increasing the coating width of the insulating layer 3 at the free section 20, the insulating layer 3 covers a small portion of the surface of the cathode active layer 22, so that the remaining effective coating width of the cathode active layer 22 is reduced from the original C value to the D value, thereby forming Figure 3 The structure of the "third cathode sheet" is shown.

[0093] The second manufacturing method of the above section is further described. It can be seen from the above that in this embodiment, a plurality of cathode ears 23 arranged at intervals are optionally connected to at least one side of the cathode sheet main body 21 in the width direction, and the above-mentioned insulating layer 3 is provided at the root of the cathode ear 23. The width of the insulating layer 3 covering the cathode active layer 22 in the middle section 10 is set to E (E is greater than or equal to 0), and the width of the insulating layer 3 covering the cathode active layer 22 in the free section 20 is set to F. At least in one free section 20, F is greater than E, thereby achieving the purpose of D being less than C. If this cathode sheet and Figure 3 If the "second type of anode sheet" is used in combination, then F = E + (CD). Since the two free sections 20 of the winding core of this embodiment can be designed with D less than C, the two free sections 20 of the winding core of this embodiment are designed with F greater than E.

[0094] Manufacturing method three: When coating the active material, the width of the active material coating is controlled so that the width of the active layer in the first section or the last section of the electrode is different from that in the middle section.

[0095] Assuming △d=d-d0=(BD)-(AC), the free length L of the free section 20 and the head and tail swing of the anode or cathode are deduced and calculated. It is found that in order to ensure that the anode active layer 12 at the free section 20 can completely cover the cathode active layer 22, △d and L conform to the quadratic function △d=0.5L 2 +0.5L+0.2, then when △d≥0.5L 2 +0.5L+0.2, it can be ensured that the anode active layer 12 at the free section 20 can completely cover the cathode active layer 22. In other words, as long as the free length L of the free section 20 is confirmed, the minimum value of △d can be determined, thereby confirming the size of the anode active layer 12 widening in the free section 20 or the cathode active layer 22 narrowing in the free section 20. The free length L of the free section 20 can be specifically understood as the area where the cathode active layer 22 on the cathode sheet is narrowed, or it can be understood as the area where the anode active layer 12 on the anode sheet is widened. The following table shows three experimental data.

[0096] Serial number Free section length L / m Pole piece head and tail swing s / mm The width of the active layer widened / narrowed in the free section △d / mm 1 0.2 0.25-0.37 0.3 2 0.3 0.33-0.46 0.4 3 0.4 0.42-0.65 0.5

[0097] Please refer again Figure 3, since the first free section 20 on the left is wound at the innermost part, its free length L is shorter, so this embodiment can optionally change the active layer corresponding to the small section L of the first two pole ears (widen the anode active layer 12 and narrow the cathode active layer 22); since the tail free section 20 on the right is wound at the outermost part, its free length L is longer, so this embodiment can optionally change the active layer corresponding to the small section L of the last three pole ears (widen the anode active layer 12 and narrow the cathode active layer 22). Usually, the free length L of the free section 20 will fall within the range of 0.1m to 0.5m. According to △d=0.5L 2 +0.5L+0.2, the corresponding width dimension Δd of the active layer in the free section 20 changes within the range of 0.3-0.7 mm, preferably d0 is 1.9-3.5 mm, and d is 2.2-4.2 mm.

[0098] like Figure 3 As shown, when A and B are equal, △d is actually the difference of (CD), then (CD) ≥ 0.5L 2 +0.5L+0.2, (CD) specifically 0.3-0.7mm.

[0099] like Figure 3 As shown, when C and D are equal, △d is actually the difference of (BA), then (BA) ≥ 0.5L 2 +0.5L+0.2, (BA) specifically is 0.3-0.7mm.

[0100] See also Figure 4 The present embodiment further provides a battery cell monomer, which includes an outer film 4 (currently mostly aluminum-plastic film), a positive electrode tab 5, a negative electrode tab 6 and the above-mentioned winding core. A plurality of cathode tabs 23 are assembled and welded to form a positive electrode tab 5 and connected to the cathode sheet body 21. A plurality of anode tabs 13 are assembled and welded to form a negative electrode tab 6 and connected to the anode sheet body 11. The outer film 4 wraps the winding core, and the positive electrode tab 5 and the negative electrode tab 6 are exposed relative to the outer film 4. When the positive electrode tab 5 and the negative electrode tab 6 are respectively connected to the outside, the purpose of charging or discharging the winding core can be achieved.

[0101] See also Figure 5 The present embodiment further provides a battery, which includes a shell 7 and the above-mentioned battery cell 8. The shell 7 generally includes a shell 71 and a top cover 72. At least one battery cell 8 is accommodated in the shell 71. Two poles 721 are generally provided on the top cover 72. One pole 721 is used to connect to the positive electrode tab 5, and the other pole 721 is used to connect to the negative electrode tab 6, so that the positive and negative electrodes inside the winding core are led outward through the pole 721.

[0102] Embodiment 2

[0103] This embodiment provides a method for preparing a pole piece, which mainly includes the following steps:

[0104] S1: Provide a substrate, which can be understood as a current collector made of a metal foil. The substrate can also be understood as a current collector on which other functional layers have been pre-coated on the metal foil. The functional layer may be fully coated on the metal foil or partially coated on the metal foil. The functional layer may be a conductive carbon layer coated to increase conductivity, or an adhesive layer coated to increase the bonding strength between the active layer and the substrate, etc.

[0105] S2: coating the active layer on the substrate using a coating mechanism to form a material strip, Figure 6 to Figure 7 The following are all small sections of the strip, such as Figures 6 to 8 As shown, the material strip includes at least one pole piece active material coating area in the length direction (i.e., X direction) and the width direction (i.e., Y direction), and an active layer is coated on the pole piece active material coating area by a coating mechanism. The pole piece has a first section, a middle section, and a tail section connected in sequence in the length direction (i.e., X direction), and the pole piece active material coating area has a corresponding active material coating area first section, an active material coating area middle section, and an active material coating area tail section;

[0106] S3: The cutting mechanism cuts the material strip to form the pole piece, and makes the effective width of the active layer of at least part of the first section and / or the last section of the pole piece different from the effective width of the active layer of at least part of the middle section of the pole piece. In this step, after cutting the material strip, in addition to changing the effective width of the active layer of the first section, the last section or the middle section of the pole piece, at least one side of the pole piece in the width direction can be cut as follows: Figures 6 to 8 A plurality of pole ear portions are shown which are arranged at intervals along the X direction.

[0107] The effective width here refers to the length of the active material on the electrode substrate that is not covered by other inactive materials after coating and cutting in the width direction of the electrode (ie, the Y direction).

[0108] See also Figure 3 As can be seen from the above embodiment 1, the first and last sections of the pole piece are equivalent to two free sections 20. When the pole piece is wound to form a winding core, the free section 20 of the first section of the pole piece will be wound at the head position inside the winding core, and the free section 20 of the last section of the pole piece will be wound at the tail position of the winding core. Figures 6 to 8 , Figures 6 to 8 The figures show that a small section of the pole ear (i.e., cathode ear or anode ear) has been cut out of multiple pole pieces after step S3. The active material coating area of ​​each complete pole piece (the area between two dotted line rings along the X direction is a complete pole piece) is understood as Figures 6 to 8The area covered with active layer between the "starting end" (the location of the lower dotted line circle) and the "ending end" (the location of the upper dotted line circle) shown in the figure. Figures 6 to 8 As shown, the material strip of this embodiment can be optionally provided with two electrode active material coating areas in the Y direction, that is, the material strip includes two electrode sheets in the Y direction. Correspondingly, the cutting mechanism needs to cut out the pole ear portions on one side of the two electrode sheets respectively in the Y direction. Figure 6 , Figure 7 or Figure 8 The M line segment in the figure can cut the material strip into two pole pieces in the Y direction, thereby improving the manufacturing efficiency of the pole pieces and further improving the manufacturing efficiency of the core.

[0109] Please continue reading Figures 6 to 8 In this embodiment, after the pole piece is cut in step S3, a pole ear portion is formed on one side of the first section, the middle section and the tail section of the pole piece. Assume that each pole piece is formed with (n-1) pole ear portions in the width direction after cutting in step S3. The (n-1) pole ear portions make the pole piece have n pole ear center distances on one side in the width direction. In this embodiment, Figure 6 , Figure 7 or Figure 8 The area coated with the active layer between the starting end and the second pole ear shown in is understood as the first section of the active material coating area. In this embodiment, the area coated with the active layer between the second pole ear and the (Dn-3)th pole ear is optionally understood as the middle section of the active material coating area. In this embodiment, the area coated with the active layer between the (Dn-3)th pole ear and the Dnth pole ear is optionally understood as the tail section of the active material coating area. In other embodiments, the pole ear may not be provided on one side of the first section and the tail section of the pole piece in the width direction, and multiple pole ears are only provided on one side of the middle section of the pole piece.

[0110] In order to achieve that the effective width of the active layer remaining in the first section or / and the last section of the pole piece is different from the effective width of the active layer remaining in the middle section of the pole piece, this embodiment provides the following first implementation method (by cutting):

[0111] In the above-mentioned step S3, the cutting mechanism has a first cutting path and a second cutting path for cutting the material strip in different widths in the Y direction, wherein the cutting mechanism cuts according to the first cutting path to obtain the first section and / or the tail section of the pole piece; the cutting mechanism cuts according to the second cutting path to obtain the middle section of the pole piece, and the middle section of the pole piece at least partially has a plurality of pole ear portions spaced apart in the width direction, and the pole ear portion at least includes a portion of the uncoated area of ​​the active material.

[0112] When the active layer coated in step S2 is a cathode active layer, the cutting width of the second cutting path is smaller than the cutting width of the first cutting path, and the cutting mechanism must cut the cathode active layer area when cutting according to the first cutting path, so that the effective width of the cathode active layer remaining in the first section and / or the tail section of the electrode piece is smaller than the effective width of the cathode active layer in the middle section of the electrode piece, that is, at this time, it can be formed Figure 3 The second cathode sheet is a sheet in which D is smaller than C. Optionally, the width of the cathode active layer cut by the first cutting path in the Y direction is 0.3 mm to 0.7 mm. When the cutting mechanism cuts according to the second cutting path, the cathode active layer may or may not be cut. If the cutting mechanism cuts according to the second cutting path, the width of the cathode active layer cut by the second cutting path may be 0.1 to 0.2 mm. Optionally, Figure 6 As shown, in step S2, in addition to the cathode active layer, if an insulating layer is also coated, wherein the insulating layer and the cathode active layer are arranged on the same surface of the substrate, and the insulating layer is arranged on one side or both sides of the material strip where multiple cathode ears need to be cut, then the cutting mechanism cuts the cathode active layer area according to the first cutting path to narrow the effective width of the remaining cathode active layer of the first section and / or the tail section of the electrode piece, and the cutting mechanism also removes all insulating layers in the non-cathode ear area of ​​the first section of the active material coating area and / or the tail section of the active material coating area along the Y direction.

[0113] When the active layer coated in step S2 is an anode active layer, the cutting width of the second cutting path is greater than the cutting width of the first cutting path, and the cutting mechanism must cut the anode active layer region when cutting according to the second cutting path, so that the effective width of the anode active layer remaining in the first section and / or the tail section of the electrode piece is greater than the effective width of the anode active layer in the middle section of the electrode piece, that is, at this time, it can be formed Figure 3 In the "first type of anode sheet" where B is greater than A, optionally, the width of the anode active layer of the second cutting path in the Y direction is 0.3mm-0.7mm. Among them, when the cutting mechanism cuts according to the first cutting path, the anode active layer may not be cut, or the anode active layer may be cut. If the cutting mechanism cuts the anode active layer according to the first cutting path, the width of the anode active layer of the first cutting path may be 0.1-0.2mm. Here, the width of the active layer cut refers to the length of the active layer portion cut by the cutting mechanism in the width direction of the electrode sheet.

[0114] In order to achieve that the effective width of the active layer remaining in the first section or / and the last section of the pole piece is different from the effective width of the active layer remaining in the middle section of the pole piece, this embodiment provides the following second implementation method (by directly coating active layers of different widths on the corresponding areas of the substrate):

[0115] When the active layer coated in step S2 is a cathode active layer, an insulating layer may be optionally coated on the substrate, and the insulating layer and the cathode active layer are arranged on the same surface of the substrate, the width of at least part of the cathode active layer coated on the middle section of the active material coating area of ​​the pole piece is greater than the width of at least part of the cathode active layer coated on the first section and / or the last section of the active material coating area of ​​the pole piece, and after cutting in step S3, the width of at least part of the cathode active layer at the first section and / or the last section of the pole piece is less than the width of at least part of the cathode active layer in the middle section of the pole piece, that is, at this time, it can be formed Figure 3 The "second cathode sheet" in which D is less than C. In step S3, optionally, after the electrode sheet is cut by the cutting mechanism, a cathode ear is formed on one side in the width direction. Then, in step S2, the insulating layer needs to be provided on the side where the cathode ear is to be cut. Optionally, in step S2, after coating the insulating layer and the cathode active layer, the width of at least part of the cathode active layer coating in the middle section of the electrode sheet active material coating area is 0.3-2 mm greater than the width of at least part of the cathode active layer coating in the first section and / or the tail section of the electrode sheet active material coating area.

[0116] When the active layer coated in step S2 is an anode active layer, the width of at least part of the anode active layer coated on the middle section of the active material coating area of ​​the pole piece is smaller than the width of at least part of the anode active layer coated on the first section and / or the last section of the active material coating area of ​​the pole piece. After cutting in step S3, the width of at least part of the anode active layer at the first section and / or the last section of the pole piece is finally larger than the width of at least part of the anode active layer in the middle section of the pole piece. That is, at this time, it can be formed. Figure 3 The “first type of anode sheet” in which B is smaller than A. Optionally, in step S2, after coating the anode active layer, the width of at least part of the anode active layer coating in the middle section of the active material coating area of ​​the electrode sheet is 0.3-2 mm greater than the width of at least part of the anode active layer coating in the first section and / or the tail section of the active material coating area of ​​the electrode sheet.

[0117] In order to achieve that the effective width of the active layer remaining in the first section or / and the last section of the pole piece is different from the effective width of the active layer remaining in the middle section of the pole piece, this embodiment provides the following third implementation method (by covering a part of the active layer with an insulating layer):

[0118] In step S2, the coating mechanism has a first covering width and a second covering width with different covering widths for the active layer. The coating mechanism coats the insulating layer of the first covering width on at least one side of the middle section of the active material coating area in the width direction. The coating mechanism coats the insulating layer of the second covering width on at least one side of the first section and / or the tail section of the active material coating area in the width direction.

[0119] In step S2, if the active layer is a cathode active layer, the second covering width is greater than 0, the first covering width is greater than or equal to 0, and the second covering width is greater than the first covering width. In step S3, the electrode piece can be cut according to the conventional cutting width, so that at least part of the cathode active layer of the first section or the last section of the final electrode piece is covered by the insulating layer, so as to form Figure 3 The third cathode sheet in which D is less than C. More specifically, when the third implementation is used, the electrode sheet is cut in arrangement S3 only to cut the cathode sheet body part or the cathode sheet body and part of the insulating layer area, so that the cathode sheet is cut out of the cathode ear part, and this process does not require cutting the effective cathode active layer area.

[0120] In step S2, if the active layer is an anode active layer, the second covering width is greater than or equal to 0, the first covering width is greater than 0, and the second covering width is less than the first covering width. In step S3, the pole piece can be cut according to the conventional cutting width, so that at least part of the anode active layer in the middle section of the final pole piece is covered by the insulating layer. More specifically, when the third implementation is used, the pole piece is cut in arrangement S3 only to cut the anode sheet body or the anode sheet body and part of the insulating layer area, so that the anode ear is cut out of the anode sheet, and this process does not require cutting the effective anode active layer area.

[0121] See also Fig. 9 , Fig. 9 The step S3 in the method for preparing the pole piece of this embodiment is shown as the specific method adopted by the first implementation method described above:

[0122] First, the cutting mechanism uses the second cutting path to cut the middle section of the pole piece (the middle section of the pole piece in this embodiment can be selected as Figure 6 and Figure 7 A plurality of spaced-apart pole lugs are cut out on at least one side in the width direction (i.e., a middle area between the second pole lug of the first section and the third pole lug of the last section) Figure 6 and Figure 7 The cutting mechanism uses the first cutting path to cut the first section of one of the pole pieces (optionally, Figure 6 and Figure 7 The area between the starting end and the second pole ear shown in the figure) and the tail section of another adjacent pole piece (optionally Figure 6 and Figure 7 A plurality of pole lugs (i.e., the area between the third last pole lug and the end end shown in FIG. 1 ) are cut out on at least one side in the width direction (i.e., the Y direction) to form a plurality of pole lugs (i.e., the area between the third last pole lug and the end end shown in FIG. Figure 6 and Figure 7 The regions corresponding to Dn-3 to D2 shown in FIG. Figure 3 The "second cathode sheet" or "first anode sheet" described in the present invention.

[0123] Next, the cutting mechanism and the material strip move relative to each other along the length direction of the material strip (it can be understood that the material strip can be stationary and then the cutting mechanism moves, or it can be understood that the material strip is continuously released and the cutting mechanism does not move along the length direction of the material strip), and the cutting mechanism repeats the above cutting process for the remaining pole pieces along the length direction of the material strip.

[0124] Among them, along Figure 6 or Figure 7 The step of cutting the pole sheet into two pole sheets along the M line segment can be completed after executing the above step S3 and before executing the above step S2, or the material strip can be wound up after all the pole sheets in the material strip have executed steps S2 and S3 (that is, after all the pole sheets in the material strip have their pole ears cut out), and then the material strip can be released again at other positions and cut along the M line segment.

[0125] This paragraph supplements the explanation that the widths of the active layers of the two free segments of the anode sheet or cathode sheet produced by the first implementation method mentioned above are changed, and the changed width value is actually (BA) or (CD). In other embodiments, if the width of the active layer of only one of the free segments of the anode sheet or cathode sheet needs to be changed, the first cutting path may be applied to one of the first or last segments of the electrode sheet, and the second cutting path may be applied to the other segment.

[0126] Optionally, refer again to Figure 6 , Figure 7 and Fig. 9 , when the surface of the electrode piece is pre-coated with an insulating layer before executing the step S3, when the cutting mechanism cuts the first section of one electrode piece and the tail section of another adjacent electrode piece along the width direction of the electrode piece during the execution of the step S3, the cutting mechanism will remove part of the cathode active layer while also removing part of the cathode ear area (i.e. Figure 6 and Figure 7 All the insulating layers are removed from the respective areas Dn-3 to D2 shown in the figure.

[0127] See also Fig.10 , Fig.10 The following is a specific method used in step S2 and step S3 of the method for preparing the pole piece of this embodiment when applying the third implementation method described above:

[0128] First, in step S2, the middle section of the electrode piece (the middle section in this embodiment may be selected as Figure 8The middle area between the second pole ear of the first segment and the third pole ear of the last segment as shown in the figure is coated with an insulating layer of a first covering width on at least one side in the width direction, and the coating mechanism is applied to the first segment of one of the pole pieces (optionally Figure 8 The area between the starting end and the second pole ear shown in the figure) and the tail section of another adjacent pole piece (optionally Figure 8 The electrode piece is coated with an insulating layer of a second covering width on at least one side in the width direction (the area between the third last pole ear portion and the end end shown in FIG); then, in step S3, a cutting mechanism is used to cut the side of the pole piece coated with the insulating layer in the width direction, so that the pole ear portion is cut out of the first section, the middle section and the tail section of the pole piece, so that Figure 3 The "third cathode sheet" described in.

[0129] Then, the coating mechanism repeats the coating process described in the previous paragraph on the remaining pole pieces along the length direction of the material strip, and the cutting mechanism repeats the cutting process described in the previous paragraph on the remaining pole pieces along the length direction of the material strip.

[0130] This paragraph supplements the explanation that the width of the active layer of the two free segments of the anode sheet or cathode sheet produced by the second implementation method mentioned above can also be changed, and the changed width value is actually (BA) or (CD). In other embodiments, if the width of the active layer of only one of the free segments of the anode sheet or cathode sheet needs to be changed, then one of the first or last segments of the electrode sheet shall apply the first covering width, and the other segment may apply the second covering width.

[0131] Embodiment 3

[0132] This embodiment provides a method for preparing a core, comprising the following steps:

[0133] First, an anode sheet, a cathode sheet and a separator are provided, and at least one of the anode sheet and the cathode sheet is subjected to the preparation method of the electrode sheet described in the second embodiment, so that Figure 3 The “second cathode sheet”, “third cathode sheet” and “first anode sheet” shown in FIG.

[0134] Then select the anode and cathode. Figure 3 The "first cathode sheet" and "second anode sheet" in the present invention are equivalent to the structure of the cathode and anode sheets used in the current prior art, such as Figure 3 As shown, let d0=AC, let d=BD, where d0 and d are both greater than 0. In order to satisfy the condition that d is greater than d0, the method for preparing the winding core of this embodiment can select the following five electrode combinations:

[0135] The first pole piece combination: winding core selection Figure 3 The "second anode sheet" and "second cathode sheet" in the invention;

[0136] The second pole piece combination: winding core selection Figure 3 The "second anode sheet" and "third cathode sheet" in ;

[0137] The third pole piece combination: core selection Figure 3 The "first anode sheet" and "first cathode sheet" in the invention;

[0138] The fourth pole piece combination: winding core selection Figure 3 The "first anode sheet" and the "second cathode sheet" in the embodiment of the present invention;

[0139] The fifth pole piece combination: winding core selection Figure 3 The “first type of anode sheet” and the “third type of cathode sheet”.

[0140] The preparation method of the winding core of this embodiment can select any one of the five electrode sheet combinations mentioned above. After the selection is completed, the anode sheet, the separator and the cathode sheet are stacked and wound into a winding core in sequence. Among them, the first section of the anode sheet and / or the first section of the cathode sheet are located at the initial end of the winding core, and the tail section of the anode sheet and / or the tail section of the cathode sheet are located at the end of the winding core.

[0141] By adopting the electrode sheet preparation method in Example 2, the purpose of d being greater than the d0 can be achieved, thereby ensuring that even if the anode sheet or cathode sheet at the free section 20 has a certain degree of head and tail swinging problem, it can also be ensured that the anode active layer 12 at the free section 20 can still completely cover the cathode active layer 22, thereby improving the stability and safety of the core during the charging and discharging process and is conducive to extending the service life of the core, so as to meet the design requirements of high safety and high service life for battery applications in the automotive field.

[0142] See also Figure 3 As can be seen from the first embodiment, in order to ensure that the anode active layer 12 at the free section 20 can completely cover the cathode active layer 22, the free length L and △d of the free section 20 of the pole piece meet the quadratic function △d≥0.5L 2 +0.5L+0.2. The free length L of the free section 20 of the tail section can be specifically understood as the distance between the pole piece cutting position and the winding needle when winding the winding core.

[0143] Embodiment 4

[0144] See also Fig.11The present embodiment provides a manufacturing device for a pole piece, which mainly includes a feeding mechanism (not shown in the figure), a winding mechanism (not shown in the figure), a laser 100 and a plurality of rollers 200, wherein the feeding mechanism is used to automatically feed out a material strip 300, and the winding mechanism is used to automatically wind up the fed material strip, the laser 100 and the plurality of rollers 200 are optionally arranged between the feeding mechanism and the winding mechanism, the plurality of rollers 200 are used to support the material strip 300 to ensure that the material strip 100 can be stably transported and gradually wound into the winding mechanism, and the laser 100 is used to cut the material strip 300 in the width direction, so that each pole piece in the material strip can be cut out of the pole ear portion.

[0145] See also Fig.12 The manufacturing equipment of the pole piece of the present embodiment may further include a slitting knife 400, which is used to divide the material strip 300 into two material segments 301 in the width direction. Each material segment 301 includes a plurality of pole pieces connected in sequence. Subsequently, it is only necessary to cut the two material segments 301 separately to obtain a plurality of pole pieces.

[0146] Please also read Fig.13 and Fig.14 The manufacturing equipment of the electrode sheet of this embodiment may also include a coating mechanism 500, which is used to coat the coating liquid 501 inside on the foil substrate 600. The coating liquid 501 may be an anode or cathode active slurry, or an insulating slurry. When the coating liquid 501 is an anode or cathode active slurry, the coating mechanism 500 will coat the active layer 700 ( Fig.13 In black in the figure), when the coating liquid 501 is an insulating slurry, the coating mechanism 500 will coat the insulating layer 3 ( Fig.13 ), the material of the insulating layer 3 can be selected as TF8, and the width of the liquid outlet of the coating mechanism 500 can be automatically adjusted to meet the different coating widths of the active layer or the insulating layer in various areas on the material strip. Optionally, the foil substrate 600 can be pre-coated with an active layer 700, and the coating mechanism 500 will coat the active layer 700 by covering part of the active layer 700 with the insulating layer 3 to change the effective width of the remaining active layer 700 in the designated area on the material strip.

[0147] Embodiment 5

[0148] See also Fig.15The present embodiment provides a core preparation device, which mainly includes a feeding mechanism (not shown in the figure), a winding machine and a cutting knife (not shown in the figure), wherein the feeding mechanism is used to automatically feed out the anode sheet, the cathode sheet and the separator, and the winding machine includes a winding needle 800, which is used to wind the fed anode sheet, the separator and the cathode sheet together. When the anode sheet, the separator and the cathode sheet are wound to a specified size, the cutting knife is used to cut off the anode sheet, the separator and the cathode sheet at the same time to produce a battery core.

[0149] The above are only preferred embodiments of the present invention, and only specifically describe the technical principles of the present invention. These descriptions are only for explaining the principles of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention, and other specific implementations of the present invention that can be associated with by technicians in this field without creative labor, should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a pole piece, characterized in that: The following steps are involved: S1: providing a substrate; S2: The coating mechanism coats the active layer on the substrate to form a material strip, wherein the material strip includes at least one pole piece active material coating area in the length and width directions, wherein the pole piece has a first section, a middle section and a tail section connected in sequence in the length direction, and the pole piece active material coating area has a corresponding active material coating area first section, an active material coating area middle section and an active material coating area tail section; S3: The cutting mechanism cuts the material strip to form the pole piece, and the effective width of at least part of the active layer of the first section and / or the last section of the pole piece is different from the effective width of at least part of the active layer of the middle section of the pole piece.

2. The method for preparing a pole piece according to claim 1, characterized in that: In step S3: the cutting mechanism has a first cutting path and a second cutting path with different cutting widths for the material strip; the cutting mechanism cuts according to the first cutting path to obtain the first section and / or the tail section of the pole piece; the cutting mechanism cuts according to the second cutting path to obtain the middle section of the pole piece, and the middle section of the pole piece at least partially has a plurality of pole ear portions spaced apart in the width direction, and the pole ear portion at least includes a portion of the uncoated area of ​​the active material.

3. The method for preparing a pole piece according to claim 2, characterized in that: The active layer is a cathode active layer, the cutting width of the second cutting path is smaller than the cutting width of the first cutting path, and the cutting mechanism cuts the cathode active layer region when cutting along the first cutting path.

4. The method for preparing a pole piece according to claim 3, characterized in that: When the cutting mechanism cuts according to the first cutting path, the width of the cathode active layer cut by the first cutting path is 0.3 mm-0.7 mm.

5. The method for preparing a pole piece according to any one of claims 3 to 4, characterized in that: When the cutting mechanism cuts according to the second cutting path, the cathode active layer is not cut.

6. The method for preparing a pole piece according to any one of claims 3 to 4, characterized in that: When the cutting mechanism cuts according to the second cutting path, the cathode active layer region is cut.

7. The method for preparing a pole piece according to claim 6, characterized in that: The width of the cathode active layer cut by the second cutting path is 0.1-0.2 mm.

8. The method for preparing a pole piece according to any one of claims 2 to 4 and 7, characterized in that: In step S2, an insulating layer is also coated on the substrate. The insulating layer and the active layer are arranged on the same surface of the substrate, and the insulating layer is arranged on one side or both sides of the material strip where a plurality of cathode ears are to be cut.

9. The method for preparing a pole piece according to claim 2, characterized in that: The active layer is an anode active layer, the cutting width of the second cutting path is greater than the cutting width of the first cutting path, and the cutting mechanism cuts the anode active layer region when cutting along the second cutting path.

10. The method for preparing a pole piece according to claim 9, characterized in that: When the cutting mechanism cuts according to the second cutting path, the width of the anode active layer cut by the second cutting path is 0.3-0.7 mm.

11. The method for preparing a pole piece according to any one of claims 9 to 10, characterized in that: When the cutting mechanism cuts according to the first cutting path, the anode active layer region is not cut.

12. The method for preparing a pole piece according to any one of claims 9 to 10, characterized in that: When the cutting mechanism cuts according to the first cutting path, the anode active layer region is cut.

13. The method for preparing a pole piece according to claim 12, characterized in that: The width of the anode active layer cut by the first cutting path is 0.1-0.2 mm.

14. The method for preparing a pole piece according to claim 1, characterized in that: In step S2, an insulating layer is further coated on the substrate, the insulating layer and the active layer are arranged on the same surface of the substrate, the active layer is a cathode active layer, and the coating width of at least part of the cathode active layer on the middle section of the active material coating area of ​​the pole piece is greater than the coating width of at least part of the cathode active layer on the first section and / or the tail section of the active material coating area of ​​the pole piece; In step S3, after cutting, the width of at least a portion of the cathode active layer at the beginning and / or the end of the pole piece is smaller than the width of at least a portion of the cathode active layer at the middle section of the pole piece.

15. The method for preparing a pole piece according to claim 14, characterized in that: In step S3, the electrode piece is cut by the cutting mechanism to form a cathode ear on one side in the width direction; In the step S2, the insulating layer is disposed on the side where the cathode ear portion needs to be cut out.

16. The method for preparing a pole piece according to any one of claims 14 to 15, characterized in that: In step S2, after coating the insulating layer and the cathode active layer, the width of at least part of the cathode active layer coating in the middle section of the pole piece active material coating area is 0.3-2 mm larger than the effective width of at least part of the cathode active layer coating in the first section and / or the tail section of the pole piece active material coating area.

17. The method for preparing a pole piece according to claim 1, characterized in that: In step S2, the active layer is an anode active layer, and the width of at least part of the anode active layer coating in the middle section of the pole piece active material coating area is smaller than the width of at least part of the anode active layer coating in the first section and / or the tail section of the pole piece active material coating area. In step S3, after cutting, the effective width of at least part of the anode active layer of the first section and / or the last section of the pole piece is greater than the effective width of at least part of the anode active layer of the middle section of the pole piece.

18. The method for preparing a pole piece according to claim 17, characterized in that: In step S2, the width of at least part of the anode active layer coating in the middle section of the pole piece active material coating area is 0.3-2 mm smaller than the width of at least part of the anode active layer coating in the first section and / or the last section of the pole piece active material coating area.

19. The method for preparing a pole piece according to claim 1, characterized in that: In step S2, the coating mechanism has a first covering width and a second covering width with different covering widths for the active layer; The coating mechanism coats the insulating layer of the first covering width on at least one side of the middle section of the active material coating area in the width direction, and the coating mechanism coats the insulating layer of the second covering width on at least one side of the first section and / or the last section of the active material coating area in the width direction.

20. The method for preparing a pole piece according to claim 19, characterized in that: In step S2, the active layer is a cathode active layer, the second covering width is greater than 0, the first covering width is greater than or equal to 0, and the second covering width is greater than the first covering width; In step S3, after cutting, at least part of the cathode active layer of the electrode sheet in the first section or the last section is covered by the insulating layer.

21. The method for preparing a pole piece according to claim 19, characterized in that: In step S2, the active layer is an anode active layer, the second covering width is greater than or equal to 0, the first covering width is greater than 0, and the second covering width is less than the first covering width, In step S3, after cutting, at least part of the anode active layer of the pole piece in the middle section is covered by the insulating layer.

22. A method for preparing a core, characterized in that: The following steps are involved: Providing an anode sheet, a cathode sheet and a separator, wherein at least one of the anode sheet and the cathode sheet is prepared by the method for preparing the electrode sheet according to any one of claims 1 to 21; The anode sheet, the separator and the cathode sheet are stacked and wound into a winding core, the anode sheet first section and the cathode sheet first section are located at the initial end of the winding core, and the anode sheet tail section and the cathode sheet tail section are located at the tail section of the winding core.

23. The method for preparing a winding core according to claim 22, characterized in that The effective width value of at least part of the active layer in the middle section of the anode sheet is A, the effective width value of at least part of the active layer in the first section and / or the last section of the anode sheet is B, the effective width value of at least part of the active layer in the middle section of the cathode sheet is C, the effective width value of at least part of the active layer in the first section and / or the last section of the cathode sheet is D, d0=AC, d=BD, and d is greater than d0.

24. The method for preparing a winding core according to claim 23, characterized in that: The d0 is 1.9-3.5 mm, d is 2.2-4.2 mm, and d-d0 is 0.3-2.3 mm.

25. The method for preparing a winding core according to claim 23, characterized in that: The d0 is 1.9-3.5 mm, d is 2.5-4.9 mm, and d-d0 is 0.6-3 mm.

26. The method for preparing a winding core according to claim 23, characterized in that: Assume that the length of the free section is L, △d=d-d0=(BD)-(AC), and △d≥0.5L2+0.5L+0.2, wherein L is 0.1m-0.5m, and △d is 0.3-0.7mm.

27. The method for preparing a winding core according to claim 26, characterized in that: When A and B are equal, the Δd is the difference of (CD), and the (CD) ≥ 0.5L2 + 0.5L + 0.

2.

28. The method for preparing a winding core according to claim 26, characterized in that: When C and D are equal, the Δd is the difference of (BA), and the (BA) ≥ 0.5L2 + 0.5L + 0.

2.

29. A pole piece manufacturing device, characterized in that: The method for preparing a pole piece according to any one of claims 1 to 21 is applied.

30. A core preparation device, characterized in that: A winding machine is included, which is used to wind the anode sheet, the separator and the anode sheet which have been stacked in sequence into a winding core.

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