Battery cell manufacturing method and battery using same

Abstract

The invention discloses a battery cell manufacturing method and a battery using the same, and the battery cell manufacturing method comprises the following steps: step A, selecting a base film with a thickness of less than 5 [mu] m, and coating at least one side with an adhesive layer to prepare a diaphragm; step B, alternately placing the diaphragms and the battery pole pieces, and then applying pressure through a composite mechanism to form a prefabricated composite belt by the diaphragms and the battery pole pieces; step C, winding the composite belt through a winding mechanism, and then applying pressure through a pressure plate mechanism to prepare a battery roll core; according to the battery cell manufactured by the method provided by the invention, a mode of prefabricating and laminating the diaphragm and the pole piece is adopted, so that the laminating effect consistency between the diaphragm and the pole piece is better, the foreign matter defect is more easily detected when the battery cell is subjected to a short-circuit test, and the risk caused by missing detection of the defective battery cell is reduced.

Description

Technical Field

[0001] The present invention specifically relates to a method for manufacturing a battery cell and a battery using the same. Background Art

[0002] In the current lithium-ion battery manufacturing process, the cell types are mainly divided into square wound, laminated, and cylindrical. Considering the comprehensive performance and cost, the square wound type is the most main cell type. With the increasing requirements for the endurance energy density of lithium-ion power batteries and the development of the lithium battery separator process technology, the thickness of traditional polyolefin separators has been continuously reduced.

[0003] The separator of the existing battery core has a relatively large thickness, generally about 12 microns, resulting in a large volume and low energy density of the manufactured core. In order to improve the energy density, some use ultra-thin separators to make the core, but the reduction of the separator thickness also brings some problems accordingly, such as the reduction of the puncture strength of the separator, the reduction of the toughness of the separator, resulting in a high short-circuit rate at the end of the cell, wrinkling of the separator during winding, poor coating, lithium deposition at the R corner of the wound cell, etc., thus leading to a low battery yield and poor battery performance. In the general trend of increasing battery energy density and reducing separator thickness, it becomes particularly important to solve the problems in the production and manufacturing end. For this reason, we propose a method for manufacturing a battery cell and a battery using the same. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for manufacturing a battery cell and a battery using the same, so as to solve the problems of low battery yield and poor battery performance of the existing core made of ultra-thin separator as mentioned in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A method for manufacturing a battery cell, comprising the following steps:

[0006] Step A: Select a base film with a thickness of less than 5 μm and at least one side coated with an adhesive layer to make a separator;

[0007] Step B: Alternately place the separator and the battery electrode plate, and then apply pressure through a composite mechanism to form a prefabricated composite tape;

[0008] Step C: Wind the composite tape through a winding mechanism, and then apply pressure through a pressing plate mechanism to make a battery core.

[0009] By pre-pressing and compounding the ultra-thin separator before winding, it is convenient to form an integral body of the battery electrode plate and the separator.

[0010] Preferably, the thickness of the base film is 3 - 5 μm.

[0011] It is beneficial to make an ultra-thin separator, thus facilitating the reduction of the volume of the later-made core.

[0012] Preferably, the adhesive layer on the surface of the base film is at least one of PVDF and PMMA, and inorganic ceramics are mixed in the adhesive layer.

[0013] It is convenient to achieve a better bonding effect and ensure the uniformity during heat dissipation. The inorganic ceramics conduct heat to make the heat distribution uniform.

[0014] Preferably, an inorganic ceramic layer is provided between the adhesive layer and the base film.

[0015] It is convenient to better conduct heat through the inorganic ceramic layer, making the heat distribution uniform and having a good insulation effect.

[0016] Preferably, a heating component is included inside the composite mechanism, and the maximum heating temperature provided by the heating component is 200 °C.

[0017] It is convenient to better bond and fix the separator to the electrode plate during prefabrication and lamination.

[0018] Preferably, the maximum pressure when the composite mechanism presses the separator and the battery electrode plate is 10 t.

[0019] It is convenient to better make the separator and the electrode plate in close contact.

[0020] Preferably, the length and width dimensions of the composite mechanism are adjustable.

[0021] It is convenient to process according to separators of different sizes, so that the separator and the battery electrode plate form an integral body before winding.

[0022] Preferably, the material of the base film is PE.

[0023] It is convenient to make according to existing materials.

[0024] Preferably, the pressing plate mechanism includes an upper pressing plate and a lower pressing plate that are symmetric up and down, and electric heating wires are provided inside both the upper pressing plate and the lower pressing plate.

[0025] It is convenient to better press the wound core to improve the connection tightness between the cores.

[0026] A battery includes a wound core made by using the cell manufacturing method described above;

[0027] A housing, and the housing is disposed outside the wound core.

[0028] It is convenient to make a battery with a smaller volume and a higher energy density.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] The prefabricated diaphragm obtained by the present invention and the composite tape of the pole piece will not wrinkle, ensuring the coating effect of the diaphragm on the pole piece in the battery, good R-angle fitting effect of the battery cell, good battery interface, easier detection of foreign object defects during the short-circuit test of the battery cell, ensuring the performance and safety of the battery, reducing the risk of undetected defective battery cells. In addition, the dimensions of the diaphragm and pole piece composite mechanism are adjustable in the length and width directions, the production method of the battery cell is simple, different-sized battery cells can be compounded, and the applicability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic flow chart of the present invention;

[0032] Figure 2 is a schematic structural diagram of the adhesive layer of the present invention;

[0033] Figure 3 is a schematic structural diagram of the composite mechanism of the present invention;

[0034] Figure 4 is a schematic diagram of the composite structure of the negative electrode, positive electrode and diaphragm of the present invention;

[0035] Figure 5 is a schematic diagram of the diaphragm made by the present invention;

[0036] Figure 6 is a schematic diagram of wrinkles existing in the existing diaphragm. DETAILED DESCRIPTION OF THE INVENTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Embodiment 1

[0039] Please refer to Figure 1 , the present invention provides a technical solution: a method for manufacturing a battery cell, including the following steps:

[0040] Step A: Select a base film with a thickness of less than 5 μm and at least one side is coated with an adhesive layer to make a diaphragm;

[0041] Step B: Alternately place the diaphragm and the battery pole piece, and then apply pressure through the composite mechanism to form a prefabricated composite tape;

[0042] Step C: Wind the composite tape through the winding mechanism, and then apply pressure through the pressing plate mechanism to make a battery core.

[0043] By pre - pressing and laminating the ultra - thin separator before winding, it is convenient to form an integral body of the battery electrode sheet and the separator, avoiding problems such as wrinkles in the separator, poor coating, and lithium deposition at the R - corner of the wound battery core during later winding and pressing. Before winding, the separator and the winding core are formed into an integral body to improve toughness and ensure the strength effect of the separator.

[0044] Preferably, the thickness of the base film is 3 - 5μm.

[0045] It is conducive to making an ultra - thin separator, thus facilitating the reduction of the volume of the later - made winding core and improving the energy density of the battery.

[0046] Preferably, the adhesive layer on the surface of the base film is at least one of PVDF and PMMA, and inorganic ceramics are mixed in the adhesive layer.

[0047] It is convenient for better bonding effect and ensuring the uniformity during heat dissipation. The heat is evenly distributed through the heat conduction of inorganic ceramics. Inorganic ceramics refer to ceramic materials obtained by processes such as high - temperature sintering from inorganic substances, non - carbon - based materials. Common inorganic ceramic materials include alumina, silicon nitride, silicon carbide, zirconia, etc. These materials usually do not contain organic substances, have higher melting points, stronger corrosion resistance, better thermal stability, and higher hardness, and are suitable for high - temperature, wear - resistant, and special application environments.

[0048] Preferably, there is an inorganic ceramic layer between the adhesive layer and the base film.

[0049] It is convenient for better heat conduction through the inorganic ceramic layer to make the heat evenly distributed, and it has a good insulation effect, forming two different production directions with the inorganic ceramics mixed in the adhesive layer to meet different processing technologies.

[0050] Preferably, the inner side of the composite mechanism contains a heating component, and the maximum heating temperature provided by the heating component is 200℃.

[0051] It is convenient for better bonding and fixing of the separator and the electrode sheet during pre - lamination.

[0052] Preferably, the maximum pressure when the composite mechanism presses the separator and the battery electrode sheet is 10t.

[0053] It is convenient for better close contact between the separator and the electrode sheet, improving the tightness after connection.

[0054] Preferably, the length and width dimensions of the composite mechanism are adjustable.

[0055] It is convenient for processing according to different - sized separators, so that the separator and the battery electrode sheet form an integral body before winding, reducing the delamination between the separator and the battery electrode sheet, scratching of the separator by the battery electrode sheet, or wrinkling of the separator during winding.

[0056] Preferably, the material of the base film is PE.

[0057] It is convenient to manufacture according to existing materials, ensuring the use effect of the separator during the production of the battery core.

[0058] Preferably, the pressing plate mechanism includes an upper pressing plate and a lower pressing plate that are symmetrically arranged up and down, and both the inner sides of the upper pressing plate and the lower pressing plate are provided with electric heating wires.

[0059] It is convenient to better press the wound core, improving the connection tightness between the cores.

[0060] A battery includes a core wound by a core manufacturing method;

[0061] A housing is arranged outside the core.

[0062] It is convenient to manufacture batteries with smaller volume and higher energy density.

[0063] The working principle and usage process of the present invention: The manufacturing process of its core is a winding manufacturing method, using an ultra-thin PE base film with a thickness of 3 - 5 microns and a bonding coating applied on one or both sides of the base film. The separator bonding coating is PVDF, PMMA type or a mixture of both and its mixed coating with inorganic ceramics. The core manufacturing method is as follows: First, pre-compound the separator and the electrode sheet, then wind the pre-compounded separator and electrode sheet composite tape, and finally, thermally press the wound core through a pressing plate mechanism to form the core. The pre-compounded separator and electrode sheet composite tape separator will not wrinkle, ensuring the coating effect of the separator on the electrode sheet in the battery. The R corner of the core fits well, which is beneficial to improving the battery interface consistency, ensuring the performance and safety of the battery. By using the method of pre-fitting the separator and the electrode sheet, the fitting effect between the separator and the electrode sheet is more consistent. When the core is subjected to a short-circuit test, foreign object defects are more easily detected, reducing the risk of undetected defective cores. Moreover, the dimensions of the separator and electrode sheet composite mechanism in the length and width directions are adjustable, and the core manufacturing method is simple, and different-sized cores can be compounded, with strong applicability.

[0064] Embodiment 2

[0065] Please refer to Figures 1 - 6 , the present invention provides a technical solution: A method for manufacturing a battery core, an ultra-thin 5-micron base film is selected, and a PVDF coating is prepared on 1 surface. The manufacturing steps are as follows:

[0066] Step S1: Convey the separators 101 and 102 to the composite mechanism 400 through a unwind mechanism, and send the positive electrode sheet 200 to the composite mechanism 400 through a unwind mechanism for thermocompression lamination to obtain a pre-compounded separator and positive electrode sheet tape 501;

[0067] Step S2: Feed the separator and the prefabricated composite tape 501 of the positive electrode sheet to the winding mechanism 600 through the conveying mechanism

[0068] Step S3: Feed the negative electrode sheet 300 to the winding mechanism 600 through the unwinding mechanism;

[0069] Step S4: Wind the separator, the prefabricated composite tape 501 of the positive electrode sheet and the negative electrode sheet 300 with the winding needle 601;

[0070] Step S5: Thermally press the wound core through the pressing plate mechanism 700 to form the battery cell 800.

[0071] Embodiment 3

[0072] Please refer to Figures 1 - 4 , the present invention provides a technical solution: a method for manufacturing a battery cell, using an ultra-thin 5-micron base film and preparing PVDF coatings on two surfaces. The manufacturing steps are as follows:

[0073] Step S1: Feed the separators 101 and 102 to the composite mechanism 400 through the unwinding mechanism, and feed the negative electrode sheet 300 to the composite mechanism 400 through the unwinding mechanism for thermal pressing and composite to obtain the prefabricated composite tape 501 of the separator and the negative electrode sheet;

[0074] Step S2: Feed the prefabricated composite tape 501 of the separator and the negative electrode sheet to the winding mechanism 600 through the conveying mechanism

[0075] Step S3: Feed the positive electrode sheet 200 to the winding mechanism 600 through the unwinding mechanism;

[0076] Step S4: Wind the prefabricated composite tape 501 of the separator and the negative electrode sheet and the positive electrode sheet 300 with the winding needle 601;

[0077] Step S5: Thermally press the wound core through the pressing plate mechanism 700 to form the battery cell 800.

[0078] Embodiment 4

[0079] Please refer to Figures 1 - 6 , the present invention provides a technical solution: a method for manufacturing a battery cell, using an ultra-thin 5-micron base film and preparing PVDF coatings on two surfaces. The manufacturing steps are the same as those in Embodiment 2.

[0080] Embodiment 5

[0081] Please refer to Figures 1 - 6 , the present invention provides a technical solution: a method for manufacturing a battery cell, using an ultra-thin 5-micron base film and preparing PVDF coatings on two surfaces. The manufacturing steps are as follows:

[0082] Step S1: The separators 101 and 102 are conveyed to the composite mechanism 400 through the unwinding mechanism, and the positive electrode sheet 200 and the negative electrode sheet 300 are sent to the composite mechanism 400 through the unwinding mechanism for hot pressing and compounding to obtain the prefabricated composite tape 501 of the negative electrode sheet, separator and positive electrode sheet;

[0083] Step S2: The prefabricated composite tape 501 of the negative electrode sheet, separator and positive electrode sheet is conveyed to the winding mechanism 600 through the conveying mechanism;

[0084] Step S3: The prefabricated composite tape 501 of the negative electrode sheet, separator and positive electrode sheet is wound by the winding needle 601;

[0085] Step S4: The wound core is further hot pressed through the pressing mechanism 700 to form the battery cell 800.

[0086] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a battery cell, characterized in that, It includes the following steps: Step A: Select a base film with a thickness of less than 5 μm, and at least one side is coated with an adhesive layer to form a separator; Step B: Alternately place the separator and the battery electrode plate, and then apply pressure through a composite mechanism to form a prefabricated composite tape; Step C: Wind the composite tape through a winding mechanism, and then apply pressure through a pressing plate mechanism to form a battery core.

2. The method for manufacturing a battery cell according to claim 1, characterized in that: The thickness of the base film is 3-5 μm.

3. A method for manufacturing a battery cell according to claim 1, characterized in that: The adhesive layer on the surface of the base film is at least one of PVDF and PMMA, and inorganic ceramics are mixed in the adhesive layer.

4. A method for manufacturing a battery cell according to claim 1, characterized in that: There is an inorganic ceramic layer between the adhesive layer and the base film.

5. A method for manufacturing a battery cell according to claim 1, characterized in that: The inner side of the composite mechanism contains a heating component, and the maximum heating temperature provided by the heating component is 200 °C.

6. A method for manufacturing a battery cell according to claim 1, characterized in that: The maximum pressure when the composite mechanism presses the separator and the battery electrode plate is 10 t.

7. A method for manufacturing a battery cell according to claim 1, characterized in that: The length and width dimensions of the composite mechanism are adjustable.

8. A method for manufacturing a battery cell according to claim 1, wherein: The material of the base film is PE.

9. A method for manufacturing a battery cell according to claim 1, wherein: The pressing plate mechanism includes an upper pressing plate and a lower pressing plate that are symmetric up and down, and electric heating wires are provided on the inner sides of the upper pressing plate and the lower pressing plate.

10. A battery, characterized in that: It includes a core made by using the core manufacturing method according to any one of claims 1-9; A housing, and the housing is arranged outside the core.

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