Symmetrical battery with ceramic coating

Abstract

The utility model provides a symmetrical battery with a ceramic coating, and belongs to the technical field of batteries. The symmetrical battery with the ceramic coating comprises a diaphragm, a packaging layer, two tabs and two single-sided pole pieces. According to the utility model, the ceramic coating is coated on one active material layer, so that the single-sided pole piece can be directly obtained, the diaphragms are respectively propped against the other active material layer on the two single-sided pole pieces, and the packaging layer is wrapped on the peripheries of the core bag and the two tabs. The single-sided pole piece is convenient to prepare, the problem that the current collector is damaged or the wiping surface has coating material residues is solved, meanwhile, the single-sided pole piece is not curled, and the symmetrical battery testing accuracy is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a symmetrical battery with a ceramic coating. Background Art

[0002] At present, new methods and means for mechanism analysis, failure analysis, material evaluation and system verification in the development process of lithium-ion batteries are constantly emerging. Symmetrical batteries are an important means of evaluating electrode materials and structures. In the process of electrode material and structure verification, the use of symmetrical batteries to test the solid-phase diffusion capacity of electrodes can provide data support for electrode material selection and pore structure design. In the prior art, the preparation method of symmetrical batteries is usually to adjust the entire battery to a specified charge state and then disassemble it, cut the electrode pieces to obtain two completely identical positive or negative electrode pieces, and then use solvents such as NMP or water to wipe the electrode pieces to prepare a single-sided active material electrode piece, and assemble two identical single-sided positive or single-sided negative electrode pieces into a symmetrical battery and then perform impedance testing. However, there are some problems in the existing technology: since the pole pieces of single-sided active materials are made by wiping the pole pieces with solvents such as NMP or water, the wiping process can easily cause damage to the current collector or residues of coating material on the wiping surface, resulting in poor quality of the pole pieces of single-sided active materials, affecting the experimental results of subsequent symmetrical batteries; secondly, the wiping operation is time-consuming, and the consistency and repeatability of the single-sided pole pieces are poor; finally, the single-sided pole pieces are prone to curling after wiping, resulting in poor performance of the symmetrical battery formed by two single-sided pole pieces, affecting the impedance test results. Utility Model Content

[0003] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and to provide a symmetrical battery with a ceramic coating.

[0004] The utility model proposes a symmetrical battery with a ceramic coating, comprising a diaphragm, a packaging layer, two pole tabs, and two symmetrically arranged single-sided pole pieces, wherein the single-sided pole pieces comprise a substrate, two active material layers respectively arranged on opposite side surfaces of the substrate, and a ceramic coating coated on one active material layer, the diaphragm respectively abuts against the other active material layer on the two single-sided pole pieces to form a core package; one end of the two pole tabs is respectively connected to the substrates of the two single-sided pole pieces; the packaging layer is wrapped around the outer periphery of the core package and the two pole tabs, and the other ends of the two pole tabs respectively protrude from the outside of the packaging layer.

[0005] Furthermore, the encapsulation layer is an aluminum-plastic film.

[0006] Furthermore, the length of the active material layer and the length of the ceramic coating are both smaller than the length of the substrate, the width of the active material layer and the width of the ceramic coating are both equal to the width of the substrate, one end of the substrate, one end of the active material layer, and one end of the ceramic coating remain flush, the other end of the substrate protrudes from one side of the active material layer and the ceramic coating respectively, and one end of the tab is connected to the other end of the substrate.

[0007] Furthermore, it also includes a connecting adhesive layer annularly arranged in the middle of the tab; a side of the connecting adhesive layer away from the tab is connected to the packaging layer.

[0008] Furthermore, the single-sided electrode sheet is one of a single-sided positive electrode sheet and a single-sided negative electrode sheet, the substrate of the single-sided positive electrode sheet is aluminum foil, the substrate of the single-sided negative electrode sheet is copper foil, the active material layer of the single-sided positive electrode sheet is a positive electrode active layer, and the active material layer of the single-sided negative electrode sheet is a negative electrode active layer.

[0009] Furthermore, the tabs of the aluminum foil connected to the single-sided positive electrode sheet are aluminum tabs, and the tabs of the copper foil connected to the single-sided negative electrode sheet are copper-nickel-plated tabs.

[0010] Furthermore, the aluminum tab is ultrasonically welded to the aluminum foil, and the copper nickel-plated tab is ultrasonically welded to the copper foil.

[0011] Furthermore, the positive electrode active layer is one of a lithium cobalt oxide active layer, a lithium iron phosphate active layer, and a lithium nickel cobalt manganese oxide active layer, and the negative electrode active layer is a graphite active layer.

[0012] Furthermore, the length of the diaphragm is 2-4 mm greater than the length of the single-sided pole piece, and the width of the diaphragm is 2-4 mm greater than the width of the single-sided pole piece.

[0013] Furthermore, the thickness of the ceramic coating is 20-60 μm.

[0014] The symmetrical battery with ceramic coating of the utility model has the following beneficial effects:

[0015] The ceramic coating is applied to an active material layer, and a single-sided pole piece can be directly obtained. The diaphragm is respectively abutted against the other active material layer on the two single-sided pole pieces, and the encapsulation layer is wrapped around the core package and the periphery of the two pole ears. Compared with the single-sided pole piece prepared by wiping the double-sided pole piece in the prior art, the single-sided pole piece in this application is easy to prepare. The single-sided pole piece in this application will not have the problem of current collector damage or coating material residue on the wiped surface. At the same time, the single-sided pole piece in this application will not curl, thereby improving the accuracy of the symmetrical battery impedance test. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to represent similar elements. The drawings described below are some embodiments of the present invention, but not all. Those skilled in the art can derive other drawings from these drawings without inventive effort.

[0017] Figure 1 This is a schematic structural diagram of a symmetrical battery with a ceramic coating according to an embodiment of the present invention;

[0018] Figure 2 This is a structural schematic diagram of a symmetrical battery with a ceramic coating according to an embodiment of the present invention, in which a separator abuts against two single-sided pole pieces;

[0019] Figure 3 This is a schematic structural diagram of a single-sided electrode in a symmetrical battery with a ceramic coating according to an embodiment of the present invention;

[0020] Figure 4 This is a schematic structural diagram of a single-sided positive electrode sheet in a symmetrical battery with a ceramic coating according to an embodiment of the present invention;

[0021] Figure 5 This is a schematic structural diagram of a single-sided negative electrode sheet in a symmetrical battery with a ceramic coating according to an embodiment of the present invention.

[0022] In the figure: 1-single-sided electrode sheet, 11-substrate, 12-active material layer, 13-ceramic coating, 14-single-sided positive electrode sheet, 141-aluminum foil, 142-positive electrode active layer, 15-single-sided negative electrode sheet, 151-copper foil, 152-negative electrode active layer, 2-diaphragm, 3-packaging layer, 4-ear, 41-connecting adhesive layer. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be arbitrarily combined with each other.

[0024] See also Figures 1 to 5A symmetrical battery with a ceramic coating according to an embodiment of the present invention includes a diaphragm 2, an encapsulation layer 3, two tabs 4, and two symmetrically arranged single-sided pole pieces 1. The single-sided pole pieces 1 include a substrate 11, two active material layers 12 respectively arranged on opposite sides of the substrate 11, and a ceramic coating 13 coated on one active material layer 12. The diaphragm 2 abuts against the other active material layer 12 on the two single-sided pole pieces 1 to form a core package. One end of the two tabs 4 is respectively connected to the substrate 11 of the two single-sided pole pieces 1. The encapsulation layer 3 wraps around the core package and the outer periphery of the two tabs 4, and the other ends of the two tabs 4 protrude from the outer side of the encapsulation layer 3.

[0025] Here, in the present application, a ceramic coating 13 is directly coated on an active material layer 12. Compared with the single-sided electrode 1 prepared by wiping the electrode with solvents such as NMP or water in the prior art, NMP is N-methylpyrrolidone, and the wiping operation is time-consuming. The operation in the present application is time-consuming, and the single-sided electrode 1 in the present application is simple to prepare; at the same time, compared with the single-sided electrode 1 in the prior art, there will be problems of current collector damage or coating residue on the wiping surface. In the present application, since the ceramic coating 13 is directly coated on an active material layer 12 and no wiping operation is adopted, the single-sided electrode 1 in the present application will not have the problem of current collector damage or coating residue on the wiping surface; in the prior art, a double-sided electrode is made into a single-sided electrode 1 by a wiping operation, and the degree of wiping at various parts of the double-sided electrode is relatively difficult to achieve. If the two sides of the core package made of the single-sided pole piece 1 and the diaphragm 2 are kept consistent, it will be difficult to obtain a single-sided pole piece 1 with good consistency and repeatability. In the present application, a ceramic coating 13 is coated on an active material layer 12. In the present application, a ceramic coating 13 of a certain thickness is conveniently installed on an active material layer 12, so the single-sided pole piece 1 made in the present application has good consistency and repeatability; the single-sided pole piece 1 made by wiping operation in the prior art is prone to curling on the wiped side of the single-sided pole piece 1, and the two sides away from each other on the core package made of the single-sided pole piece 1 and the diaphragm 2 are prone to curling, thereby causing inaccurate symmetrical battery impedance test results. In the present application, a ceramic coating 13 is directly coated on an active material layer 12, so the single-sided pole piece 1 in the present application will not curl, thereby improving the accuracy of the symmetrical battery impedance test.

[0026] Specifically, an active material layer 12 is provided on each of the two opposite sides of the substrate 11 of the present application, and a ceramic coating 13 is coated on one of the active material layers 12, thereby forming a single-sided electrode 1 having a single-sided active material; a single-sided electrode 1, a separator 2, and another single-sided electrode 1 are stacked in sequence, so that the separator 2 abuts against the other active material layer 12 on the two single-sided electrode sheets 1, thereby forming a core package; two tabs 4 are respectively connected to the substrate 11 on the two single-sided electrode sheets 1, and then wrapped around the core package and the outer periphery of the two tabs 4 by an encapsulation layer 3, the encapsulation layer 3 abuts against the top, side, and bottom surfaces of the core package, as well as the two tabs 4, and the end of the tab 4 away from the substrate 11 protrudes outside the encapsulation layer 3, thereby obtaining a symmetrical battery. The symmetrical battery in the present application can effectively avoid damage to the current collector or coating residue during the preparation of the single-sided electrode sheet 1, and the performance of the symmetrical battery is better, thereby improving the accuracy and reliability of the impedance test of the symmetrical battery. Symmetrical batteries require electrodes with single-sided active materials. In the prior art, one side of the electrode with double-sided active materials is wiped, but the wiping method is time-consuming, and the electrode is prone to curling, resulting in inaccurate test results for the symmetrical battery. In this application, a ceramic coating 13 is used to shield the active material on one side, thereby making a single-sided electrode 1, which is time-consuming, the electrode is not prone to curling, and the test results for the symmetrical battery are more accurate.

[0027] The encapsulation layer 3 may be an aluminum-plastic film.

[0028] The length of the active material layer 12 and the length of the ceramic coating 13 can be smaller than the length of the substrate 11, and the width of the active material layer 12 and the width of the ceramic coating 13 are equal to the width of the substrate 11. One end of the substrate 11, one end of the active material layer 12, and one end of the ceramic coating 13 remain flush, and the other end of the substrate 11 protrudes from one side of the active material layer 12 and the ceramic coating 13 respectively, and one end of the tab 4 is connected to the other end of the substrate 11.

[0029] Specifically, the bottom end of the substrate 11, the bottom end of the active material layer 12, and the bottom end of the ceramic coating 13 remain flush, the top end of the substrate 11 protrudes above the active material layer 12 and the ceramic coating 13, respectively, and one end of the tab 4 is connected to the top end of the substrate 11, that is, one end of the tab 4 is connected to the portion of the substrate 11 exposed above the active material layer 12.

[0030] The symmetrical battery with ceramic coating in this embodiment may further include a connecting adhesive layer 41 annularly arranged in the middle of the tab 4 ; a side of the connecting adhesive layer 41 away from the tab 4 is connected to the packaging layer 3 .

[0031] Specifically, when the packaging layer 3 is wrapped around the tab 4, the packaging layer 3 only abuts against the tab 4, and the tab 4 and the packaging layer 3 are not fixedly connected; the connecting adhesive layer 41 can be hot-melted with the packaging layer 3 to form a closed space, that is, the connecting adhesive layer 41 can be hot-melted with the aluminum-plastic film to form a closed space; the connecting adhesive layer 41 is hot-melted with the packaging layer 3 to fix the tab 4 and the packaging layer 3, thereby realizing the formation of a closed space inside the packaging layer 3 and improving the sealing performance of the packaging layer 3.

[0032] The single-sided electrode sheet 1 can be one of the single-sided positive electrode sheet 14 and the single-sided negative electrode sheet 15. The substrate 11 of the single-sided positive electrode sheet 14 is an aluminum foil 141, the substrate 11 of the single-sided negative electrode sheet 15 is a copper foil 151, the active material layer 12 of the single-sided positive electrode sheet 14 is a positive electrode active layer 142, and the active material layer 12 of the single-sided negative electrode sheet 15 is a negative electrode active layer 152.

[0033] The tab 4 connected to the aluminum foil 141 of the single-sided positive electrode sheet 14 may be an aluminum tab 4 , and the tab 4 connected to the copper foil 151 of the single-sided negative electrode sheet 15 may be a copper-nickel-plated tab 4 .

[0034] Specifically, after the core package is completed, the pole ear 4 is ultrasonically welded, the core package and the pole ear 4 are wrapped with an aluminum-plastic film, and the top and side seals are performed. An injection port is opened on one side of the aluminum-plastic film, and the electrolyte is injected into the inner side of the aluminum-plastic film from the injection port. After a period of time, the pole ear 4 and the aluminum-plastic film are heat-sealed to obtain a symmetrical battery. This method can effectively avoid damage to the current collector or coating residue during the preparation of the single-sided electrode 1, thereby improving accuracy and reliability.

[0035] The aluminum tab 4 can be ultrasonically welded to the aluminum foil 141 , and the copper nickel-plated tab 4 can be ultrasonically welded to the copper foil 151 .

[0036] The positive electrode active layer 142 may be one of a lithium cobalt oxide active layer, a lithium iron phosphate active layer, and a lithium nickel cobalt manganese oxide active layer, and the negative electrode active layer 152 may be a graphite active layer.

[0037] The length of the diaphragm 2 may be 2-4 mm greater than the length of the single-sided electrode piece 1 , and the width of the diaphragm 2 may be 2-4 mm greater than the width of the single-sided electrode piece 1 .

[0038] Specifically, the top of the diaphragm 2 may protrude from the top of the single-sided electrode piece 1 , the bottom of the diaphragm 2 may protrude from the bottom of the single-sided electrode piece 1 , and the bottom of the diaphragm 2 may extend beyond the bottom of the single-sided electrode piece 1 by 2-4 mm.

[0039] The thickness of the ceramic coating 13 may be 20-60 μm.

[0040] Specifically, the length of the active material layer 12 can be 105~115 cm and the width can be 55~65 cm, the length of the active material layer 12 can be 110 cm and the width can be 60 cm; the length of the ceramic coating can be 105~115 cm and the width can be 55~65 cm, the length of the ceramic coating 13 can be 110 cm and the width can be 60 cm.

[0041] Specifically, prepare a complete lithium-ion battery electrode. The active material of the double-sided electrode can be the positive or negative electrode material of the lithium-ion battery. The material of the positive electrode active layer 142 can be lithium cobalt oxide, lithium iron phosphate, or lithium nickel cobalt manganese oxide, and the material of the negative electrode active layer 152 can be graphite. The double-sided electrode can be obtained from the disassembly of a failed battery cell or the rolling process of the production line. The size of the double-sided electrode can be selected according to actual needs, for example, 110cm*60cm, that is, the length and width are 110 and 60cm respectively. 70-80wt% boehmite, 20-30wt% PVDF, and NMP with a solid content of 20-40% are placed in a high-speed blender. PVDF is polyvinylidene fluoride, and NMP is N-methylpyrrolidone. The speed is 1000-2000rpm and the stirring time is 60-120 minutes to obtain a ceramic slurry. A ceramic slurry is applied to the active material layer 12 on one side of a double-sided electrode using a brush. The electrode is then placed in an oven at 80-100°C for 30-60 minutes. After drying, a single-sided electrode 1 is obtained, with active material on one side and a ceramic coating 13 on one side. The ceramic coating 13 is 20-60 μm thick. Two identical single-sided electrode sheets 1 are separated by a separator 2 and stacked to form a core package. The separator 2 is 2-4 mm longer and 2-4 mm wider than the single-sided electrode 1. The side of the single-sided electrode 1 with the active material layer 12 faces the separator 2, and the single-sided electrode sheets 1 are symmetrically arranged on both sides of the separator 2. After ultrasonically welding the aluminum foil 141 on the single-sided positive electrode sheet 14 to the aluminum tab 4, or the copper foil 151 on the single-sided negative electrode sheet 15 to the copper-nickel-plated tab 4, the electrode is then wrapped with aluminum-plastic film for top and side sealing. A liquid injection port is provided on one side of the aluminum-plastic film. 1-2 ml of electrolyte is injected into the film through the port and then heat-sealed. This heat-seals the connecting adhesive layer 41 and the encapsulation layer 3 to securely connect the tab 4 to the aluminum-plastic film. The port is then sealed and the film is immersed at 25°C for 24 hours to produce a symmetrical battery. Electrochemical impedance spectroscopy (EIS) testing is performed at a perturbation voltage of 5 mV over a frequency range of 100 kHz to 0.01 Hz. A load of 1-1.5 MPa is applied to the immersed symmetrical battery.

[0042] Specifically, 1. This application applies a ceramic coating 13 to the active material layer 12 on one side of the substrate 11, directly obtaining a single-sided electrode 1, avoiding the tedious step of wiping the double-sided electrode. 2. Directly applying the ceramic coating 13 effectively prevents curling of the single-sided electrode 1, improving the performance of the symmetrical battery and, in turn, the accuracy of the impedance test of the symmetrical battery. Furthermore, the ceramic coating 13 is a key component of the lithium-ion battery and maintains a stable structure within the battery, preventing the introduction of other substances that could affect the test results of the symmetrical battery.

[0043] The contents described above can be implemented individually or in combination in various ways, and these variations are all within the scope of protection of the present invention.

[0044] It should be noted that, in the description of the present application, the terms "upper end", "lower end" and "bottom end" indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a..." do not exclude the presence of other identical elements in the process, method, article or device comprising the elements.

[0045] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will appreciate that modifications may be made to the technical solutions described in the above embodiments, or that some of the technical features may be replaced with equivalents; and such modifications or replacements do not deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A symmetrical battery with a ceramic coating, characterized in that: The invention comprises a diaphragm (2), an encapsulation layer (3), two pole tabs (4), and two symmetrically arranged single-sided pole pieces (1), wherein the single-sided pole piece (1) comprises a substrate (11), two active material layers (12) respectively arranged on two opposite sides of the substrate (11), and a ceramic coating (13) coated on one active material layer (12); the diaphragm (2) is respectively in contact with the other active material layer (12) on the two single-sided pole pieces (1) to form a core package; one end of the two pole tabs (4) is respectively connected to the substrate (11) of the two single-sided pole pieces (1); the encapsulation layer (3) is wrapped around the outer periphery of the core package and the two pole tabs (4), and the other ends of the two pole tabs (4) are respectively protruding from the outer side of the encapsulation layer (3).

2. A symmetrical battery with a ceramic coating according to claim 1, characterized in that: The packaging layer (3) is an aluminum-plastic film.

3. A symmetrical battery with a ceramic coating according to claim 1 or 2, characterized in that: The length of the active material layer (12) and the length of the ceramic coating (13) are both shorter than the length of the substrate (11); the width of the active material layer (12) and the width of the ceramic coating (13) are both equal to the width of the substrate (11); one end of the substrate (11), one end of the active material layer (12), and one end of the ceramic coating (13) are kept flush; the other end of the substrate (11) protrudes from one side of the active material layer (12) and the ceramic coating (13), respectively; and one end of the tab (4) is connected to the other end of the substrate (11).

4. A symmetrical battery with a ceramic coating according to claim 1 or 2, characterized in that: It also includes a connecting adhesive layer (41) annularly arranged in the middle of the tab (4); a side of the connecting adhesive layer (41) away from the tab (4) is connected to the packaging layer (3).

5. A symmetrical battery with a ceramic coating according to claim 1 or 2, characterized in that: The single-sided electrode sheet (1) is one of a single-sided positive electrode sheet (14) and a single-sided negative electrode sheet (15); the substrate (11) of the single-sided positive electrode sheet (14) is an aluminum foil (141); the substrate (11) of the single-sided negative electrode sheet (15) is a copper foil (151); the active material layer (12) of the single-sided positive electrode sheet (14) is a positive electrode active layer (142); and the active material layer (12) of the single-sided negative electrode sheet (15) is a negative electrode active layer (152).

6. The symmetrical battery with ceramic coating according to claim 5, characterized in that: The tab (4) of the aluminum foil (141) connected to the single-sided positive electrode sheet (14) is an aluminum tab (4), and the tab (4) of the copper foil (151) connected to the single-sided negative electrode sheet (15) is a copper-nickel-plated tab (4).

7. The symmetrical battery with ceramic coating according to claim 6, characterized in that: The aluminum tab (4) is ultrasonically welded to the aluminum foil (141), and the copper nickel-plated tab (4) is ultrasonically welded to the copper foil (151).

8. The symmetrical battery with ceramic coating according to claim 5, characterized in that: The positive electrode active layer (142) is one of a lithium cobalt oxide active layer, a lithium iron phosphate active layer, and a lithium nickel cobalt manganese oxide active layer, and the negative electrode active layer (152) is a graphite active layer.

9. A symmetrical battery with a ceramic coating according to claim 1 or 2, characterized in that: The length of the diaphragm (2) is 2-4 mm greater than the length of the single-sided pole piece (1), and the width of the diaphragm (2) is 2-4 mm greater than the width of the single-sided pole piece (1).

10. A symmetrical battery with a ceramic coating according to claim 1 or 2, characterized in that: The thickness of the ceramic coating (13) is 20-60 μm.

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