Electrode foil with a centrally located tab and battery

Abstract

Electrode foil with a centrally attached tab, comprising: a current collector with a side A and a side B; a primary coating layer arranged on at least one side surface of the current collector and at least partially separated from the current collector by laser action to form a slot; an active material layer arranged on at least one side surface of the current collector and coated over the primary coating layer; a tab welded to the slot.

Description

A pole piece with a centrally located pole tab, a preparation method thereof, and a battery Technical Field

[0001] The present invention relates to the technical field of battery materials, and in particular to a pole piece with a pole tab positioned in the middle, a preparation method thereof, and a battery. Background Art

[0002] In lithium battery manufacturing, welding the tabs between the pole pieces can reduce the battery's internal resistance. To achieve this, the active material at the tab welding location must be removed before the tabs can be welded to the current collector. Currently, there are multiple methods for achieving this. Laser cleaning is a new green cleaning technology that uses a galvanometer to control a laser beam, scanning the cleaning area multiple times at high speed. This process heats, vaporizes, ablates, and peels off the coating on the material surface, achieving cleaning. Laser cleaning is a highly automated, efficient, and safe solution that has been widely used.

[0003] However, laser cleaning of battery active materials is affected by multiple factors, including the battery's primary materials and formulation. Parameters often need to be adjusted based on the formulation, and some formulations are even impossible to clean. Some battery coating formulations fail to completely remove the active materials after cleaning, or high-power cleaning can damage and wrinkle the foil, failing to meet manufacturing standards. Therefore, laser cleaning of these formulations is currently unsuitable for processing battery pole pieces with centrally located tabs.

[0004] Therefore, it is necessary to find a pole piece with a centrally placed pole tab to solve the above problems.

[0005] Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a pole piece with a centrally located pole tab, which improves the effect and compatibility of laser cleaning and broadens the application range of laser in pole piece cleaning.

[0007] The present invention also provides a method for preparing the pole piece placed in the pole tab.

[0008] The present invention also provides a battery comprising the pole piece.

[0009] According to an embodiment of the first aspect of the present invention, there is provided a pole piece with a centrally located pole lug, the pole piece comprising:

[0010] A current collector having an A side and a B side;

[0011] A primer layer, the primer layer being disposed on at least one side of the current collector; the primer layer being at least partially separated from the current collector under the action of a laser to form a groove;

[0012] An active material layer, the active material layer being disposed on at least one surface of the current collector; the active material layer being coated on top of the primer layer;

[0013] The tab is welded at the recessed position.

[0014] The pole piece according to the embodiment of the present invention has at least the following beneficial effects:

[0015] In the pole piece provided by the present invention, a layer of easy-to-clean material is pre-coated on the bottom layer of the laser cleaning area. The easy-to-remove property of the coating is utilized to improve the effect and compatibility of laser cleaning, thereby increasing the process window of laser cleaning. In addition, the pole piece described in the present invention can be applied to different battery main material formulations, thereby broadening the application scope of laser in pole piece cleaning.

[0016] According to some embodiments of the present invention, a longitudinal cut extending along the width direction of the pole piece may be further provided in the groove region to be compatible with tab welding.

[0017] According to some embodiments of the present invention, the incision depth is 0.5 to 8 mm.

[0018] The width of the incision is not limited, and is also used to avoid the influence of the material area thickness when welding the tab.

[0019] According to some embodiments of the present invention, the thickness of the primer layer on a single side is 2 to 10 μm.

[0020] According to some embodiments of the present invention, the base coating area is larger than the laser cleaning area.

[0021] According to some embodiments of the present invention, the active material of the active material layer includes at least one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, and ternary metals.

[0022] According to some embodiments of the present invention, the length of the primer layer is 5 to 60 mm and is smaller than the current collector. In this case, the shape of the primer layer can be at least one of a block rectangle and a strip rectangle.

[0023] According to some embodiments of the present invention, the area of ​​the primer layer is 25 mm 2 Up to 3600mm 2 In this case, the shape of the base coating layer can be at least one of a rectangle, a circle and a polygon.

[0024] According to some embodiments of the present invention, the primer layer comprises at least one of an insulating substance and a good conductive substance.

[0025] According to some embodiments of the present invention, when the primer layer comprises an insulating substance, the components of the primer layer include, by mass percentage, a binder content of 0.5 to 5%, a conductive agent content of 0 to 7%, and an insulating substance content ≥ 90%.

[0026] According to some embodiments of the present invention, when the primer layer comprises a good conductive substance, the components of the primer layer include, by mass percentage: a binder content of 0.5 to 5%; and a conductive agent content of >95%.

[0027] According to some embodiments of the present invention, the conductive agent includes at least one of conductive carbon black and carbon nanotubes.

[0028] According to some embodiments of the present invention, the insulating material includes at least one of boehmite, alumina, and silica.

[0029] According to some embodiments of the present invention, the pole piece is an anode; and / or, the pole piece is a cathode.

[0030] According to an embodiment of the second aspect of the present invention, a method for preparing the pole piece is provided, the method comprising the following steps:

[0031] S1, coating the primer layer on the surface of the current collector;

[0032] S2, coating the active material layer on the surface treated in step S1;

[0033] S3. Using a laser cleaning device, the surface of the electrode obtained in step S2 and the active material layer and the primer layer coated thereon are cleaned to obtain the electrode.

[0034] According to some embodiments of the present invention, in step S1, the coating method includes at least one of extrusion coating and gravure coating.

[0035] According to some embodiments of the present invention, in step S3, after the cleaning process, the base coating layer and the current collector are separated to obtain grooves.

[0036] According to some embodiments of the present invention, in step S3, the cleaning method includes cleaning after rolling or cleaning after slitting.

[0037] According to some embodiments of the present invention, the length of the groove is 3 to 58 mm.

[0038] The cleaning includes laser cleaning; the cleaning refers to removing the active material layer in the corresponding area after the active material layer is set to form the groove.

[0039] According to some embodiments of the present invention, the edge of the groove is 0.5 to 5 mm away from the edge of the base coating.

[0040] According to some embodiments of the present invention, a method for preparing the cutout unit at the groove position includes at least one of metal cutting and laser cutting.

[0041] According to some embodiments of the present invention, the power of the laser cleaning is 10 to 55%.

[0042] According to some embodiments of the present invention, the scanning speed of the laser cleaning is 1000 to 2000 mm / s.

[0043] According to some embodiments of the present invention, the frequency of the laser cleaning is 800 to 1000 kHz.

[0044] According to some embodiments of the present invention, the pulse width of the laser cleaning is 20 to 30 ns.

[0045] According to an embodiment of a fourth aspect of the present invention, a battery is provided, comprising the pole piece.

[0046] According to some embodiments of the present invention, the battery includes at least one of a lithium battery, a sodium battery, and a potassium battery.

[0047] Unless otherwise specified, the term “about” in the present invention means that the error is allowed to be within the range of ±2%. For example, about 100 is actually 100±(2%×100).

[0048] Unless otherwise specified, “between” in the present invention includes the number itself, for example, “between 2 and 3” includes the endpoint values ​​2 and 3.

[0049] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0051] FIG1 is a schematic diagram of a sample preparation process of an electrode according to an embodiment of the present invention;

[0052] FIG2 is a schematic diagram of the shape of the bottom coating in the pole piece according to an embodiment of the present invention;

[0053] FIG3 is a schematic structural diagram of a pole piece according to an embodiment of the present invention;

[0054] FIG4 is a graph showing the test results of the laser cleaning effect of the pole piece provided in Example 1 of the present invention;

[0055] FIG5 is a graph showing the test results of the laser cleaning effect of the pole piece provided in Example 2 of the present invention;

[0056] FIG6 is a graph showing the test results of the laser cleaning effect of the pole piece provided in Example 3 of the present invention;

[0057] FIG7 is a graph showing the test results of the laser cleaning effect of the pole piece provided in Example 4 of the present invention;

[0058] FIG8 is a graph showing the test results of the laser cleaning effect of the pole piece provided in Comparative Example 1 of the present invention; DETAILED DESCRIPTION

[0059] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0060] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0061] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0062] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0063] Example 1

[0064] This embodiment provides a pole piece with a tab placed in the middle, comprising:

[0065] A current collector having an A side and a B side;

[0066] A primer layer, the primer layer being disposed on at least one side surface of the current collector;

[0067] An active material layer, the active material layer being disposed on at least one surface of the current collector; the active material layer being coated on top of the primer layer;

[0068] The tab is welded at the recessed position.

[0069] This embodiment also provides a method for preparing the above-mentioned tab-centered electrode sheet, the specific steps of which include:

[0070] 1) Pre-coating the primer layer on the current collector using gravure coating;

[0071] The formula of the primer layer is as follows: the binder content is 2%, the conductive agent content is 5%, and the insulating material content is 93%. The conductive agent is carbon black, the insulating material is boehmite, and the thickness of the primer layer is 10 μm.

[0072] 3) The bottom coating can be of different shapes. The bottom coating is a block-shaped rectangle with a length of 20 mm and a width of 10 mm. The length of the bottom coating is smaller than the width of the current collector.

[0073] 4) Coating the pre-primed electrode with a mixture of lithium cobalt oxide and lithium iron phosphate as the main active material;

[0074] 5) The coated electrode is laser cleaned to remove the active material and primer layer in the tab area. The cleaned groove is 15 mm long and 5 mm wide.

[0075] The battery provided in this embodiment is manufactured by applying the electrode piece placed in the center of the electrode tab to the cathode, performing laser processing, and then performing rolling, slitting, winding and other processes to complete the battery cell manufacturing.

[0076] Example 2

[0077] This embodiment provides a pole piece with a tab placed in the middle, comprising:

[0078] A current collector having an A side and a B side;

[0079] A primer layer, the primer layer being disposed on at least one side surface of the current collector;

[0080] An active material layer, the active material layer being disposed on at least one surface of the current collector; the active material layer being coated on top of the primer layer;

[0081] The tab is welded at the recessed position.

[0082] This embodiment also provides a method for preparing the above-mentioned tab-centered electrode sheet, the specific steps of which include:

[0083] 1) Pre-coating the primer layer on the current collector by extrusion coating;

[0084] The formula of the primer layer is as follows: the binder content is 2%; the conductive agent content is 98%, the conductive agent is carbon black, and the thickness of the primer layer is 10 μm.

[0085] 3) The bottom coating can be of different shapes. The bottom coating is a block-shaped rectangle with a length of 30 mm and a width of 20 mm. The length of the bottom coating is smaller than the width of the current collector.

[0086] 4) Coating the pre-primed electrode with a mixture of lithium cobalt oxide and lithium iron phosphate as the main active material;

[0087] 5) The coated electrode is laser cleaned to remove the active material and primer layer in the tab area. The cleaned groove is 25 mm long and 15 mm wide.

[0088] The battery provided in this embodiment is manufactured by applying the electrode piece placed in the middle of the electrode tab to the anode, performing laser processing, and then performing rolling, slitting, winding and other processes to complete the battery cell manufacturing.

[0089] Example 3

[0090] This embodiment provides a pole piece with a tab placed in the middle, comprising:

[0091] A current collector having an A side and a B side;

[0092] A primer layer, the primer layer being disposed on at least one side surface of the current collector;

[0093] An active material layer, the active material layer being disposed on at least one surface of the current collector; the active material layer being coated on top of the primer layer;

[0094] The tab is welded at the recessed position.

[0095] This embodiment also provides a method for preparing the above-mentioned tab-centered electrode sheet, the specific steps of which include:

[0096] 1) Pre-coating the primer layer on the current collector using gravure coating;

[0097] The formula of the primer layer is as follows: the binder content is 5%, the conductive agent content is 5%, and the insulating material content is 90%. The conductive agent is carbon black, the insulating material is boehmite, and the thickness of the primer layer is 4 μm.

[0098] 3) The bottom coating can be of different shapes. The bottom coating is a block-shaped rectangle with a length of 20 mm and a width of 10 mm. The length of the bottom coating is smaller than the width of the current collector.

[0099] 4) Coating the pre-primed electrode with a mixture of lithium cobalt oxide and lithium iron phosphate as the main active material;

[0100] 5) The coated electrode is laser cleaned to remove the active material and primer layer in the tab area. The cleaned groove is 15 mm long and 5 mm wide.

[0101] The battery provided in this embodiment is manufactured by applying the electrode piece placed in the middle of the electrode tab to the anode, performing laser processing, and then performing winding and other processes to complete the battery cell manufacturing.

[0102] Example 4

[0103] This embodiment provides a pole piece with a tab placed in the middle, comprising:

[0104] A current collector having an A side and a B side;

[0105] A primer layer, the primer layer being disposed on at least one side surface of the current collector;

[0106] An active material layer, the active material layer being disposed on at least one surface of the current collector; the active material layer being coated on top of the primer layer;

[0107] The pole tab is welded at the groove position.

[0108] This embodiment also provides a method for preparing the above-mentioned tab-centered electrode sheet, the specific steps of which include:

[0109] 1) Pre-coating the primer layer on the current collector using gravure coating;

[0110] The formula of the primer layer is as follows: the binder content is 3%; the conductive agent content is 97%, the conductive agent is carbon black, and the thickness of the primer layer is 2 μm.

[0111] 3) The bottom coating can be of different shapes. The bottom coating is a block-shaped rectangle with a length of 30 mm and a width of 20 mm. The length of the bottom coating is smaller than the width of the current collector.

[0112] 4) Coating the pre-primed electrode with a mixture of lithium cobalt oxide and lithium iron phosphate as the main active material;

[0113] 5) The coated electrode is laser cleaned to remove the active material and primer layer in the tab area. The cleaned groove is 25 mm long and 15 mm wide.

[0114] The battery provided in this embodiment is manufactured by applying the electrode piece placed in the middle of the electrode tab to the anode, performing laser processing, and then performing rolling, slitting, winding and other processes to complete the battery cell manufacturing.

[0115] Comparative Example 1

[0116] This comparative example provides a pole piece that differs from Example 1 in that it does not include a primer layer, and the primer layer has a thickness of 0 μm. The cleaning effect diagram is shown in Figure 8.

[0117] Test Case

[0118] Examples 1 to 4 and Comparative Example 1 were cleaned using a laser with a power of 10 to 55%, a scanning speed of 1000 to 2000 mm / s, a frequency of 800 to 1000 kHz, and a pulse width of 20 to 30 ns.

[0119] The sample preparation process of the electrode according to the embodiment of the present invention is shown in Figure 1, the shape and structure diagram of the primer layer in the electrode is shown in Figure 2, and the structure of the electrode according to the embodiment of the present invention is shown in Figure 3. Structure 1 is not provided with a cutout unit, and Structure 2 is provided with a cutout unit. According to the cleaning effect test results of Figures 4 to 8, it can be seen that the present invention improves the effect and compatibility of laser cleaning by adding a primer layer to the electrode, and different primer layer formulas can improve the cleaning effect. The thicker the primer layer, the better the cleaning effect.

[0120] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A tab-centered electrode, characterized in that, the electrode includes: a current collector having an A side and a B side; a bottom coating provided on at least one surface of the current collector; at least a part of the bottom coating is separated from the current collector under the action of laser to obtain a groove; an active material layer provided on at least one surface of the current collector; the active material layer is coated above the bottom coating; a tab welded at the groove position.

2. The electrode according to claim 1, characterized in that, a longitudinal incision unit extending in the width direction of the electrode is further provided at the groove position to be compatible with tab welding; preferably, the incision depth is 0.5 to 8 mm; preferably, the single-sided thickness of the bottom coating is 2 to 10 μm.

3. The electrode according to claim 1, characterized in that, the area of the bottom coating is larger than the laser cleaning area; preferably, the active material of the active material layer includes at least one of lithium cobaltate, lithium iron phosphate, lithium manganate, and ternary materials.

4. The electrode according to claim 1, characterized in that, The length of the bottom coating is 5 to 60 mm, and the length is less than that of the current collector; preferably, the area of the bottom coating is 25 mm 2 to 3600 mm 2 .

5. The electrode according to claim 1, characterized in that, the composition of the bottom coating contains at least one of an insulating material and a highly conductive material; and optionally, when the composition of the bottom coating contains an insulating material, by mass percentage, the components of the bottom coating include: binder content 0.5 to 5%, conductive agent content 0 to 7%, insulating material content ≥ 90%; and optionally, when the composition of the bottom coating contains a highly conductive material, by mass percentage, the components of the bottom coating include: binder content 0.5 to 5%; conductive agent content > 95%.

6. The electrode according to claim 5, characterized in that, the conductive agent includes at least one of conductive carbon black and carbon nanotubes; preferably, the insulating material includes at least one of boehmite, alumina, and silica.

7. The electrode according to any one of claims 1 to 6, characterized in that, the electrode is an anode; and / or, the electrode is a cathode.

8. A preparation method of the electrode according to any one of claims 1 to 6, characterized in that, the preparation method includes the following steps: S1. Coating the bottom coating on the surface of the current collector; S2. Coating the active material layer on the surface treated in step S1; S3. Cleaning the surface of the electrode obtained in step S2 and the coated active material layer and the bottom coating by using a laser cleaning instrument to obtain the electrode.

9. The preparation method according to claim 8, characterized in that, in step S3, after the cleaning treatment, the bottom coating is separated from the current collector to obtain a groove; preferably, the preparation method of the incision unit at the groove position includes at least one of hardware cutting and laser cutting; preferably, the length of the groove is 3 to 58 mm; preferably, the width of the groove is 3 to 58 mm.

10. A battery, characterized in that, it includes the electrode according to any one of claims 1 to 6.

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