A full tab cell and a preparation method thereof

Abstract

The application belongs to the technical field of lithium batteries, and particularly relates to a full-tab battery and a preparation method thereof. The full-tab battery comprises a positive electrode tab, a diaphragm, a negative electrode tab and a positive and negative electrode shell. The positive electrode tab comprises a positive electrode current collector and a positive electrode active material layer, and has a continuous blank area on the single side end part along the length direction of the positive electrode current collector, i.e. the first direction. The upper and lower surfaces of the positive electrode current collector except the blank area are provided with the positive electrode active material layer. The length of the blank area along the first direction is less than or equal to 150% of the thickness of the positive electrode active material layer and greater than 0. The thickness direction of the positive electrode current collector is the second direction, the diaphragm is folded along the same direction as the diaphragm, and is wrapped around the surface of the positive electrode tab except the blank side. The negative electrode tab is folded in the same direction as the diaphragm, and wraps the diaphragm. The end part of the negative electrode tab is inwardly recessed relative to the diaphragm in the first direction. The application has the advantages of simple structure, compactness, simple process and improved space utilization.

Description

[0001] The present application is a divisional application of the earlier application with the patent application number 2024100390913, the title of which is "Full tab battery and preparation method thereof", filed in the State Intellectual Property Office of China on January 11, 2024 by the applicant. TECHNICAL FIELD

[0002] The present application belongs to the technical field of lithium batteries, and particularly relates to a full tab battery and a preparation method thereof. BACKGROUND

[0003] The full tab structure is an effective means to reduce the internal resistance of the battery and improve the rate performance of the battery. The traditional full tab battery usually needs to reserve a large size of blank current collector, and the full tab is prepared by punching, rubbing, reserving air slot, welding bus bar or designing other complex structures, etc. The battery prepared in this way has the problems of reduced area of the electrode coating area, reduced battery capacity, low liquid injection efficiency, increased short circuit risk, complex battery structure and low production efficiency, etc.

[0004] Patent document CN111244381A discloses a full tab type button cell and a manufacturing method thereof. The button cell includes a shell, a cylindrical core formed by winding a positive electrode sheet, a separator and a negative electrode sheet; the manufacturing method includes: stacking the positive electrode, the separator and the negative electrode in sequence, with the narrow edges of the blank foils of the positive and negative electrodes being located at both sides, to form a cylindrical core in a winding manner; then, the narrow edges of the blank foils at both ends of the core are compacted to form full tabs of the positive and negative electrodes, which can allow large current to pass through and are welded to the positive and negative electrode shell covers of the button cell through conductive metal sheets; and the button cell is formed by filling insulating sealant in the positive and negative electrode shells. However, the design of the button cell needs to reserve welding space, which reduces the space utilization, and it is difficult to realize welding of the lithium metal negative electrode; liquid injection after compacting and welding of the full tabs makes it difficult for the electrolyte to be infiltrated, the liquid injection efficiency is low, and electrolyte loss is easily caused; in addition, a redundant width of the separator needs to be reserved to cover the edge of the electrode sheet, otherwise micro short circuit is easily caused, which reduces the space utilization and the yield.

[0005] Patent document CN111725552A discloses a button cell and a manufacturing method thereof. The button cell includes a winding body, a current collector disc, and a shell. The winding body and the current collector disc are both located in the shell, and the winding body is connected with the current collector disc. The winding body includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator is located between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separator, and the negative electrode sheet are wound to form the winding body. Part of the positive electrode sheet forms a positive electrode tab, and part of the negative electrode sheet forms a negative electrode tab. Both the positive electrode tab and the negative electrode tab are full tabs. The manufacturing method of the button cell is used to manufacture the above button cell. The button cell can achieve relatively low internal resistance while maintaining relatively high energy density. However, the button cell needs to reserve welding space and increase the current collector disc, which reduces the space utilization, increases the weight and cost of the battery, and makes it difficult to achieve lithium metal negative electrode welding. Furthermore, the battery needs to reserve redundant separator width to cover the edge of the electrode sheet, otherwise micro-short circuit may occur, which reduces the space utilization and the yield.

[0006] Patent document CN116154317A discloses a full-tab cylindrical lithium battery. The battery includes a winding core, one end of the winding core is provided with a positive tab, and the other end of the winding core is provided with a negative tab. The end face of the positive tab and / or the negative tab includes a flattened area after flattening treatment and a non-flattened area without flattening treatment to provide an electrolyte infiltration gap. Compared with the conventional method of flattening the entire end face of the tab, the patent document can use the gap between the layers in the non-flattened area to form an electrolyte flow channel, which facilitates the rapid infiltration of electrolyte into the winding core during the subsequent liquid injection process, shortens the liquid injection time, and greatly improves the production efficiency. However, the design of the non-flattened area increases the internal resistance of the battery, especially affecting the discharge performance of small diameter specifications, and increases the manufacturing difficulty. The battery needs to reserve redundant separator width to cover the edge of the electrode sheet, otherwise micro-short circuit may occur, which reduces the space utilization and the yield.

[0007] Patent document CN115602932A discloses a full-tab winding core and a lithium ion battery thereof. The winding core body has two end faces that are recessed inward to form flow guide cavities for exhaust and liquid infiltration. The lithium ion battery includes a full-tab winding core as described above. The flow guide cavities increase the surface area of the two end faces of the winding core body, increase the exhaust surface of the winding core body, and improve the exhaust performance of the winding core body, making the exhaust process more smooth and improving the safety of use. At the same time, the flow guide cavities increase the contact area between the winding core body and the electrolyte, making the electrolyte more easily infiltrate into the winding core body, thereby improving the liquid injection efficiency. However, the manufacturing of the flow guide cavities is complex and requires additional grooving, which reduces the full-tab area and increases the internal resistance. At the same time, the design of the flow guide cavities reduces the electrode coating area, causing the battery capacity to decrease.

[0008] In summary, the prior art full tab structure battery has the defects of complex preparation process and easy short circuit, and the coating area of the tab in the prior art is small, which reduces the battery capacity, the liquid injection efficiency and the production efficiency. SUMMARY

[0009] To improve the deficiencies of the prior art, the present application provides a full tab battery and a preparation method thereof. Specifically, the present application provides the following technical solutions:

[0010] A full tab battery, the battery comprising a positive tab, a separator, a negative tab and a positive and negative shell, the positive tab, the separator and the negative tab being located inside the positive and negative shell;

[0011] The positive tab comprises a positive current collector and a positive active material layer, and has a continuous blank area at the single side end along the length direction of the positive current collector, i.e. the first direction; the upper and lower surfaces of the positive current collector except the blank area are provided with the positive active material layer; the length of the blank area along the first direction is less than or equal to 150% of the thickness of the positive active material layer and greater than 0;

[0012] The thickness direction of the positive current collector is the second direction;

[0013] The separator is folded along the same direction as the separator, and is wrapped around the surface of the positive tab except the blank side;

[0014] The negative tab is folded along the same direction as the separator, and wraps the separator, and the end of the negative tab is recessed in the first direction relative to the separator;

[0015] The region where the negative tab is electrically connected to the negative shell forms a negative full tab, and the blank area forms a positive full tab electrically connected to the positive shell.

[0016] The present application also provides a preparation method of the above full tab battery, the method comprising the following steps:

[0017] 1) preparing a positive tab, the positive tab comprising a positive current collector and a positive active material layer, and having a continuous blank area at the single side end along the first direction of the positive current collector; the positive current collector is provided with the positive active material layer except the blank area; the length of the blank area along the first direction is less than or equal to 150% of the thickness of the positive active material layer and greater than 0;

[0018] 2) preparing a separator, a negative tab, a positive shell and a negative shell;

[0019] 3) Assembling the positive electrode diaphragm negative electrode composite structure, the blank area forms the positive electrode full tab electrically connected with the positive electrode shell, and the area where the negative electrode tab is electrically connected with the negative electrode shell forms the negative electrode full tab, and the full tab battery is obtained.

[0020] According to the application, the step of assembling the positive electrode diaphragm negative electrode composite structure specifically comprises:

[0021] 3a) folding the diaphragm, wrapping the diaphragm around the positive electrode tab, and making the diaphragm crease coincide with the non-blank side edge of the positive electrode tab to obtain a positive electrode diaphragm composite structure;

[0022] 3b) folding the negative electrode tab, wrapping the negative electrode tab around the diaphragm, and making the negative electrode tab crease coincide with the diaphragm crease to obtain a positive electrode diaphragm negative electrode composite structure by rolling.

[0023] The application has the following beneficial effects:

[0024] 1. The positive electrode blank width of the application is less than or equal to 150% of the thickness of the positive electrode material layer, and the positive electrode tab is higher than the edge of the negative electrode shell after the cell is put into the shell, and the exposed height of the positive electrode tab is not greater than the blank width of the positive electrode tab; at the same time, the negative electrode tab uses single-sided active material or uses metal as the negative electrode, and the negative electrode full tab electrically connected with the negative electrode shell is formed by folding the negative electrode tab. Thus, the active material area of the tab in the application makes full use of the height space in the battery shell as much as possible, and compared with the traditional full tab battery structure, the battery capacity can be effectively improved.

[0025] The application is especially suitable for small and micro size specifications of high capacity type, high rate type and low temperature type batteries. The application has simple and compact structure, simple process, can improve space utilization, reduce battery internal resistance, improve battery heat dissipation and improve product reliability.

[0026] 2. The diaphragm of the application completely covers the positive electrode active material area, the negative electrode tab is retracted relative to the diaphragm, and the positive electrode diaphragm negative electrode composite structure is formed by rolling, so as to prevent tab displacement and reduce the risk of short circuit in the process of winding, stacking and sealing.

[0027] 3. The diaphragm of the application completely covers the positive electrode active material area, the positive electrode blank width is not greater than 150% of the thickness of the positive electrode material layer, and the negative electrode tab is retracted relative to the diaphragm, so that the negative electrode cannot be displaced in the width direction, thereby reducing the risk of short circuit caused by the lodging or bending of the positive electrode blank during the compaction of the positive electrode full tab. At the same time, the application adopts the structure of folding the diaphragm to wrap the positive electrode tab, which reduces the risk of short circuit caused by positive electrode burrs and tab displacement.

[0028] 4. The application adopts a single-sided copper foil or metal negative electrode structure coated with negative electrode active material, uses negative electrode creases and negative electrode metal blank around the battery to form a negative electrode full tab, which simplifies the negative electrode full tab rubbing process; the application simultaneously seals the battery and compacts and forms the positive electrode full tab, without the need for additional rubbing mechanism and rubbing process, thereby improving the battery production efficiency, reducing equipment and labor investment; the application compacts the positive electrode full tab after liquid injection, has high liquid injection efficiency, does not need to reserve electrolyte permeation holes, exhaust holes and the like, simplifies the tab design, and improves the space utilization rate.

[0029] The application has the positive electrode tab blank on one end surface of the battery and the negative electrode metal blank on the other end surface, the negative electrode tab fully contacts the negative electrode shell on at least two surfaces, the negative electrode current collection area is increased, the internal resistance is reduced, heat dissipation is promoted, and the battery rate capability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 FIG. 4 is a sectional view of a positive electrode separator negative electrode composite structure in a full tab battery of Example 1.

[0031] Figure 2 FIG. 5 is a sectional view of a positive electrode separator negative electrode composite structure in a full tab battery of Example 2.

[0032] Figure 3 FIG. 6 is a sectional view of a positive electrode separator negative electrode laminated structure in a full tab battery of Comparative Example 1.

[0033] In the figure, 1 is a positive electrode current collector, 2 is a positive electrode active material layer, 3 is a separator, 4 is a metal tab (negative electrode tab), 4' is a negative electrode current collector, 5 is a negative electrode active material layer, 6 is a blank area, and 7 is a blank part. DETAILED DESCRIPTION

[0034] [Full tab battery]

[0035] As described above, the application provides a full tab battery, which includes a positive electrode tab, a separator, a negative electrode tab, and a positive and negative electrode shell, the positive electrode tab, the separator, and the negative electrode tab are located inside the positive and negative electrode shell;

[0036] The positive electrode tab includes a positive electrode current collector and a positive electrode active material layer, and has a continuous blank area on one side along the length direction of the positive electrode current collector, and the upper and lower surfaces of the rest are respectively the positive electrode active material layer; the width of the blank area is less than or equal to 150% of the thickness of the positive electrode active material layer and greater than 0;

[0037] The separator is folded along the width direction and wrapped around the positive electrode tab, and the separator crease coincides with the edge of the non-blank side of the positive electrode tab;

[0038] The negative electrode tab is folded along the width direction, wrapped around the separator, and the negative electrode tab crease and the separator crease are coincident;

[0039] The region where the negative electrode tab is electrically connected to the negative electrode shell forms a negative full tab, and the blank region forms a positive full tab electrically connected to the positive electrode shell.

[0040] According to the embodiments of the present application, the structure of folding the separator to wrap the positive electrode tab is adopted, thereby reducing the risk of short circuit caused by positive electrode burr and tab displacement.

[0041] According to the embodiments of the present application, the end of the negative electrode tab is recessed relative to the end of the separator. In the present application, the negative electrode tab is folded to wrap the separator, and the folded negative electrode tab is recessed relative to the separator, so that the negative electrode tab cannot be displaced in the width direction, thereby reducing the risk of short circuit in the full tab compaction process. Secondly, the separator completely covers the positive active material region, the width of the positive blank region is not greater than 150% of the thickness of the positive active material layer, and the negative electrode tab is recessed relative to the separator, thereby reducing the risk of short circuit caused by the positive blank region being bent or folded in the positive full tab compaction process.

[0042] According to the embodiments of the present application, the width of the blank region is less than or equal to 120% of the thickness of the positive active material layer and greater than 0, and preferably the width of the blank region is less than or equal to 100% of the thickness of the positive active material layer and greater than 0.

[0043] According to the embodiments of the present application, the negative electrode tab is a metal tab or a tab comprising a negative current collector and a negative active material layer.

[0044] According to the present application, when the negative electrode tab is a tab comprising a negative current collector and a negative active material layer, the negative active material layer is located on one side surface of the negative current collector and connected to the separator, and the negative current collector is connected to the negative electrode shell.

[0045] According to the present application, when the negative electrode tab is a tab comprising a negative current collector and a negative active material layer, the negative active material layer is located on one side surface of the negative current collector and connected to the separator, and the negative current collector is connected to the negative electrode shell; the positive electrode tab is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode tab is not greater than the length of the blank region of the positive electrode tab in the first direction.

[0046] According to the present application, the positive electrode tab, the separator and the negative electrode tab form a positive separator-negative composite structure, which can be directly used as a battery cell or formed into a battery cell after being wound or folded; the battery cell comprises a plurality of end faces, one of which is the blank region of the positive electrode tab, i.e. the positive full tab, and the rest are the negative electrode tabs, i.e. the negative full tabs.

[0047] According to the embodiment of the present application, the positive electrode tab, the separator and the negative electrode tab form a positive electrode-separator-negative electrode composite structure, wherein the separator is folded along the width direction and wrapped around the positive electrode tab, the fold of the separator coincides with the edge of the positive electrode tab; the negative electrode tab is folded along the width direction and wrapped around the separator, the fold of the negative electrode tab coincides with the fold of the separator; the composite structure can be directly used as an electric cell or after being wound or folded to form an electric cell; the electric cell comprises several end faces, one of which is the blank area of the positive electrode tab, i.e. the positive electrode full tab, and the rest are the negative electrode tabs (if the tab is a metal tab, the end face is the tab; if the tab comprises a negative electrode current collector and a negative electrode active material layer, the end face is the negative electrode current collector), i.e. the negative electrode full tab. In the present application, the active material area of the tab makes full use of the height space in the battery shell, and compared with the traditional full tab battery structure, the present application can effectively improve the battery capacity.

[0048] According to the embodiment of the present application, the thickness of the positive electrode current collector is 2% to 7% of the thickness of the positive electrode active material layer, preferably the thickness of the positive electrode current collector is 3% to 6% of the thickness of the positive electrode active material layer.

[0049] According to the embodiment of the present application, the width of the negative electrode tab is less than the width of the positive electrode blank area, preferably the width of the negative electrode tab is 5% to 50% of the width of the positive electrode blank area.

[0050] According to the embodiment of the present application, the positive electrode current collector is selected from any one of foamed aluminum, carbon-coated aluminum foil, aluminum mesh and aluminum foil, preferably aluminum foil, for example carbon-coated aluminum foil.

[0051] According to the embodiment of the present application, the width of the positive electrode current collector is the height in the battery shell + (0.2mm to 5mm). In the present application, the length of the positive electrode current collector is not particularly limited, which can meet the size requirements of the required electric cell; for example, for a 0962 type button cell, when the diameter of the electric cell is 8.8mm and the height is 6mm, the length of the positive electrode current collector is generally 80mm to 100mm.

[0052] According to the embodiment of the present application, the positive electrode active material is selected from at least one of carbon fluoride, manganese dioxide, lithium iron phosphate, lithium cobaltate, lithium nickel cobalt manganese oxide, for example carbon fluoride.

[0053] According to the embodiment of the present application, the thickness of the positive electrode active material layer is 150 to 400μm.

[0054] According to the embodiment of the present application, the separator is selected from any one of non-woven fabric, polypropylene, polyethylene, polypropylene composite polyethylene, non-woven fabric with ceramic coating, polypropylene with ceramic coating, for example polypropylene composite polyethylene separator with ceramic coating.

[0055] According to an embodiment of the present application, the width of the separator is 2*(positive electrode coating area width+positive electrode active material layer thickness+positive electrode blank area width / 8+positive electrode current collector thickness / 2)~2*(positive electrode coating area width+positive electrode active material layer thickness+positive electrode blank area width / 4+positive electrode current collector thickness / 2), and the thickness of the separator is 5 μm~15 μm.

[0056] According to an embodiment of the present application, the negative electrode tab is selected from metal tabs, for example, any one selected from metal lithium negative electrode tab, lithium-magnesium alloy negative electrode tab, lithium-copper composite negative electrode tab, lithium-aluminum alloy negative electrode tab, copper composite negative electrode tab, preferably metal lithium negative electrode tab.

[0057] According to an embodiment of the present application, the width of the metal tab is the width of the separator-the width of the positive electrode blank area*(5%~50%), and the thickness is 30 μm~150 μm.

[0058] According to an embodiment of the present application, the negative electrode tab is selected from tabs including a negative electrode current collector and a negative electrode active material layer, and is a metal negative electrode structure in which the negative electrode current collector is coated with the negative electrode active material layer on one side.

[0059] According to an embodiment of the present application, the negative electrode current collector is selected from at least one of copper foil, foamed copper, carbon-coated copper foil, copper mesh, foamed nickel, and nickel mesh.

[0060] According to an embodiment of the present application, the negative electrode active material is selected from one of silicon-carbon, graphite, and lithium titanate.

[0061] According to an embodiment of the present application, the thickness of the negative electrode active material layer is 200 μm~500 μm, and the thickness of the negative electrode current collector is 4.5 μm~350 μm.

[0062] [Preparation of full-tab battery]

[0063] As described above, the present application also provides a method for preparing the above full-tab battery, which includes the following steps:

[0064] 1) preparing a positive electrode tab including a positive electrode current collector and a positive electrode active material layer, having a continuous blank area on one side along the length direction of the positive electrode current collector, and the upper and lower surfaces of the remaining part being the positive electrode active material layer; the width of the blank area is less than or equal to 150% of the thickness of the positive electrode active material layer and greater than 0;

[0065] 2) preparing a separator, a negative electrode tab, a positive electrode shell, and a negative electrode shell;

[0066] 3) assembling the positive separator-negative electrode composite structure, the blank area forms the positive full tab which is electrically connected with the positive shell, the area of the negative electrode tab which is electrically connected with the negative shell forms the negative full tab, and the full tab battery is obtained.

[0067] According to the embodiment of the present application, the specific steps of assembling the positive separator-negative electrode composite structure include:

[0068] 3a) folding the separator, wrapping the separator around the positive electrode tab, the fold of the separator coincides with the edge of the positive electrode tab on the non-blank side, and the positive separator composite structure is obtained;

[0069] 3b) folding the negative electrode tab, wrapping the negative electrode tab around the separator, the fold of the negative electrode tab coincides with the fold of the separator, and the positive separator-negative electrode composite structure is obtained by rolling.

[0070] According to the present application, the step 3) further includes:

[0071] 3c) winding or folding the positive separator-negative electrode composite structure to obtain the battery cell.

[0072] Specifically, the step 3) further includes:

[0073] 3c) winding or folding the positive separator-negative electrode composite structure to obtain the battery cell, and the battery cell includes a plurality of end faces, one of which is the blank area of the positive electrode tab, i.e. the positive full tab, and the rest are the negative electrode tabs, i.e. the negative full tabs.

[0074] According to the present application, the step 3) further includes:

[0075] 3d) placing the battery cell into the negative shell so that the positive electrode tab is higher than the edge of the negative shell;

[0076] 3e) injecting liquid along the position of the separator, standing, covering the positive shell and pressing the seal to obtain the full tab battery.

[0077] According to the embodiment of the present application, the step 3a) specifically includes:

[0078] folding the separator along the width direction, the projection of the separator coincides with the positive material area on the positive electrode tab, the projection width of the separator on the positive blank area is less than or equal to 1 / 4 of the width of the blank area, the fold of the separator coincides with the fold of the positive electrode tab, and the positive separator composite structure is obtained.

[0079] According to the embodiment of the present application, the step 3b) specifically includes: folding the negative electrode tab along the width direction, the projection of the negative electrode tab coincides with the projection area of the separator and is inwardly retracted, the width of the inward retraction is less than or equal to the width of the blank area, the fold of the separator coincides with the fold of the negative electrode tab, the negative active material area coincides with the separator, and the positive separator-negative electrode composite structure is obtained by rolling.

[0080] According to the present application, step 3b) specifically comprises: folding the negative electrode tab along the second direction, the negative electrode tab projection coincides with the separator projection area and is inwardly retracted, the width of the inward retraction is less than or equal to the width of the blank area, the separator crease coincides with the negative electrode tab crease, and the negative active material area coincides with the separator. The positive electrode-separator-negative electrode composite structure is obtained by rolling.

[0081] According to the embodiment of the present application, step 3d) specifically comprises: placing the battery cell into the negative electrode shell, so that the positive electrode tab is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode tab is not greater than the blank width of the positive electrode tab.

[0082] According to the present application, step 3d) specifically comprises: placing the battery cell into the negative electrode shell, so that the positive electrode tab is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode tab is not greater than the length of the blank area of the positive electrode tab along the first direction.

[0083] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0084] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0085] The full tab battery and its preparation method according to the present application will be further described in detail below in conjunction with specific embodiments. It should be understood that the following examples are only illustratively described and explained the present application, and should not be interpreted as a limitation on the scope of protection of the present application. Any technology realized based on the above description of the present application is covered within the scope of protection intended by the present application.

[0086] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0087] Example 1

[0088] This embodiment provides a method for preparing a full-tab battery with an inner cavity height of 6mm and an inner cavity diameter of 8.8mm, including the following steps: See Figure 1 As shown, a carbon-coated aluminum foil with a width of 6.3 mm and a thickness of 15 μm is used as the positive electrode current collector 1. A positive electrode active material 2 with a width of 5.9 mm and a thickness of 300 μm is coated on both sides of the positive electrode current collector 1 along its length direction. The specific selection of the positive electrode active material 2 is set according to actual needs. In this embodiment, fluorinated carbon is selected as the positive electrode active material 2. There is a blank area 6 at one end of the length direction of the positive electrode current collector 1. The width of the blank area 6 is 0.4 mm. The positive electrode current collector 1 coated with the positive electrode active material 2 forms a positive electrode sheet. A separator 3 with a width of 12.6 mm and a thickness of 12 μm is folded in half along its width direction and wrapped on the positive electrode active material 2. The fold of the separator 3 coincides with the non-blank side edge of the positive electrode current collector 1. A negative electrode sheet 4 with a width of 12.3 mm and a thickness of 60 μm is folded in half and wrapped on the separator 3. The fold of the negative electrode sheet 4 coincides with the fold of the separator. The specific selection of the negative electrode 4 is set according to actual needs. It can be a metal material or a non-metal material. In this embodiment, lithium metal is selected as the negative electrode 4.

[0089] A positive electrode separator and negative electrode composite structure is obtained by roll forming. The composite structure is then wound to obtain a cell with an outer envelope diameter of 8.8 mm. The cell is placed in the negative electrode shell, and Beijing Chemical Reagent Research Institute 012 electrolyte is injected. The cell is then left to stand under vacuum at room temperature for 10 minutes. Finally, the positive electrode shell is covered and hydraulically sealed to obtain a full-tab battery.

[0090] The yield rate of the omni-tab button battery prepared in this embodiment is over 95%. Compared with traditional omni-tab batteries, the width of the positive electrode active region (width of the positive electrode material) of the omni-tab button battery prepared in this embodiment is increased by more than 20%. The average internal resistance of the omni-tab button battery prepared in this embodiment is 5 ohms, the discharge capacity at 1C at room temperature is greater than or equal to 50mAh, and the discharge capacity at 0.01C at -20℃ is greater than or equal to 40mAh.

[0091] Example 2

[0092] This embodiment provides a method for preparing a full-tab battery with an inner cavity height of 6mm and an inner cavity diameter of 8.8mm, including the following steps: See Figure 2As shown, a carbon-coated aluminum foil with a width of 6.3 mm and a thickness of 15 μm is used as the positive current collector 1, and a positive active material 2 with a width of 5.9 mm and a thickness of 200 μm is coated on the positive current collector 1 along the length direction on both sides. The specific selection of the positive active material 2 is set according to actual needs. In this embodiment, lithium nickel cobalt manganese oxide is selected. The positive current collector 1 has a blank area 6 in the length direction. The width of the blank area 6 is 0.4 mm. The positive current collector 1 coated with the positive active material 2 forms a positive electrode tab. The separator 3 with a width of 12.6 mm and a thickness of 12 μm is folded along the width direction, and the separator 3 is coated on the positive active material 2. The crease of the separator 3 coincides with the edge of the non-blank side of the positive current collector 1. A copper foil (i.e., negative current collector 4') with a width of 12.3 mm and a thickness of 6 μm is coated with a negative active material layer 5 with a thickness of 400 μm on one side surface. In this embodiment, the negative active material layer 5 is coated with a silicon-carbon negative material to form. The copper foil (i.e., negative current collector 4') provided with the negative active material layer 5 is used as a negative electrode tab. The negative electrode tab is folded and coated on the separator 3. The crease of the negative electrode tab coincides with the crease of the separator 3. The positive separator negative composite structure is obtained by using a roller to shape. The composite structure is wound to obtain a battery cell with an outer envelope diameter of 8.8 mm. The battery cell is placed in a negative shell, injected with a commercial silicon-carbon electrolyte, and vacuumed at room temperature for 10 minutes. The positive shell is covered and hydraulically sealed to obtain a full-tab button cell.

[0093] The yield of the full-tab button cell prepared in this embodiment is more than 95%. Compared with the traditional full-tab button cell, the width of the positive active area of the full-tab button cell prepared in this embodiment is increased by more than 20%.

[0094] Embodiment 3

[0095] A full-tab button cell includes a positive current collector 1, a separator 3, a negative electrode tab, and a positive and negative shell. The positive current collector 1, the separator 3, and the negative electrode tab are located inside the positive and negative shell.

[0096] The positive current collector 1 is folded into a folded structure. The outer surface of the positive current collector 1 is provided with a positive active material layer 2 and a blank area 6. The blank area 6 is located at one end of the positive current collector 1 away from the crease. The width of the blank area 6 is less than or equal to 150% of the thickness of the positive active material 2. The separator 3 is folded and wrapped outside the positive active material 2. The crease of the separator 3 overlaps the crease of the positive current collector 1. The end of the separator 3 is located between the end of the positive current collector 1 and the end of the positive active material 2. The negative electrode tab wraps the separator 3. The crease of the negative electrode tab overlaps the crease of the separator 3. The end of the negative electrode tab is inwardly recessed relative to the end of the separator 3. The width of the inwardly recessed negative electrode tab is less than the width of the blank area 6.

[0097] The blank area 6 of the positive current collector 1 forms a positive electrode tab that is electrically connected to the positive electrode shell. The negative electrode sheet is folded and wraps around the diaphragm 3. The folded negative electrode sheet forms a negative electrode tab that is electrically connected to the negative electrode shell.

[0098] In this embodiment, the end of the negative electrode sheet 4 away from the crease is the blank part 7. The crease of the negative electrode sheet and the blank part 7 of the negative electrode sheet are electrically connected to the negative electrode shell. Folding the negative electrode sheet and shrinking it inward relative to the diaphragm 3 prevents the negative electrode sheet from shifting in the width direction, reducing the risk of short circuit during the compaction process of the full electrode tab.

[0099] The positive current collector 1, the separator 3, and the negative electrode sheet are folded to form a battery cell. The battery cell includes several end faces, one of which is the blank area 6 of the positive current collector 1, and the other end faces are the creases or blank areas 7 of the negative electrode sheet. The width of the blank area 6 is less than or equal to 120% of the thickness of the positive active material 2.

[0100] The thickness of the positive electrode current collector 1 is 2% to 7% of the thickness of the positive electrode active material layer 2. The positive electrode current collector 1 is selected from any one of aluminum foam, carbon-coated aluminum foil, aluminum mesh, and aluminum foil. In this embodiment, it is carbon-coated aluminum foil. The width of the positive electrode current collector 1 is 6.3 mm and the thickness is 15 μm; the width of the positive electrode active material 2 is 5.9 mm and the thickness is 300 μm; the width of the separator 3 is 12.6 mm and the thickness is 12 μm; and the width of the negative electrode sheet is 12.3 mm and the thickness is 60 μm.

[0101] Comparative Example 1

[0102] This comparative example provides a method for fabricating a conventional all-tab battery with an inner cavity height of 6 mm and an inner cavity diameter of 8.8 mm, including the following steps: See [link to documentation]. Figure 3 As shown, a carbon-coated aluminum foil with a width of 5.4 mm and a thickness of 15 μm is used as the positive electrode current collector 1. A positive electrode active material 2 with a width of 4.9 mm and a thickness of 300 μm is coated on both sides of the positive electrode current collector 1 along its length. In this comparative example, fluorinated carbon is used as the positive electrode active material. A blank area with a width of 0.5 mm exists at one end of the positive electrode current collector along its length. The positive electrode current collector coated with the positive electrode active material forms the positive electrode sheet. Two separators 3 with a width of 5.3 mm and a thickness of 12 μm are respectively coated on the positive electrode active material, with 0.3 mm of the positive electrode blank area exposed. A negative electrode sheet 4 with a width of 5.5 mm and a thickness of 120 μm is coated on one side of the separator, with the negative electrode sheet on the positive electrode blank area side recessed 0.3 mm relative to the separator. In this comparative example, lithium metal is used as the negative electrode sheet.

[0103] The positive electrode separator negative electrode laminated structure is wound to obtain a battery cell with an outer envelope diameter of 8.8 mm, the full tab of the positive electrode and the negative electrode is respectively flattened, the battery cell is placed in a negative electrode shell, a type 012 electrolyte of Beijing Chemical Reagent Institute is injected, vacuum standing is performed at room temperature for 10 minutes, a positive electrode shell is covered and hydraulic sealing is performed to obtain a conventional full tab battery.

[0104] The yield of the full tab button cell prepared in the present comparative example is 80%, the average internal resistance of the full tab button cell prepared in the present comparative example is 8 ohms, the average discharge capacity at room temperature 1C is 38 mAh, and the average discharge capacity at-20°C 0.01C is 29 mAh.

[0105] The above has exemplarily described the specific embodiments of the present application through the examples. However, the protection scope of the present application is not limited to the above exemplified embodiments. Any modification, equivalent replacement, improvement, etc. made by the skilled in the art within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A full-tab button cell, comprising a positive tab, a separator, a negative tab and a positive-negative shell, the positive tab, the separator and the negative tab are located inside the positive-negative shell; characterized in that, the positive tab comprises a positive current collector and a positive active material layer, and has a continuous blank area at one side end along the length direction of the positive current collector, i.e., the first direction; the upper and lower surfaces of the positive current collector except the blank area are provided with the positive active material layer; the length of the blank area along the first direction is less than or equal to 150% of the thickness of the positive active material layer and greater than 0; the thickness direction of the positive current collector is the second direction; the separator is folded along the same direction as the separator, and is wrapped around the surface of the positive tab except the blank side; the negative tab is folded along the same direction as the separator, and is wrapped around the separator, and the end of the negative tab is recessed in the first direction relative to the separator; the negative tab is electrically connected with the negative shell to form a negative full tab, and the blank area forms a positive full tab electrically connected with the positive shell; the width of the negative tab recessed is less than the width of the positive blank area, and the width of the negative tab recessed is 5% to 50% of the width of the positive blank area; the negative tab is a metal tab or a tab comprising a negative current collector and a negative active material layer; when the negative tab is a tab comprising a negative current collector and a negative active material layer, the negative active material layer is located on one side surface of the negative current collector and connected with the separator, and the negative current collector is connected with the negative shell; the positive tab is higher than the edge of the negative shell, and the exposed height of the positive tab is not greater than the length of the positive tab blank area along the first direction.

2. The full-ledge button cell battery of claim 1, wherein, The positive tab, the separator and the negative tab are a positive-separator-negative composite structure, which can be directly used as a battery cell or formed into a battery cell after being wound or folded.

3. A method of producing the full tab button cell of any one of claims 1-2, characterized by, The method comprises the following steps: 1) preparing a positive tab, the positive tab comprising a positive current collector and a positive active material layer, and having a continuous blank area at one side end along the first direction of the positive current collector; the positive current collector except the blank area is provided with the positive active material layer; the length of the blank area along the first direction is less than or equal to 150% of the thickness of the positive active material layer and greater than 0; 2) preparing a separator, a negative tab, a positive shell and a negative shell; 3) assembling a positive-separator-negative composite structure, the blank area forms a positive full tab electrically connected with the positive shell, and the area where the negative tab is electrically connected with the negative shell forms a negative full tab, to obtain the full-tab button cell; wherein the step of assembling the positive-separator-negative composite structure comprises: 3a) folding the separator to wrap the separator around the positive tab to obtain a positive-separator composite structure; 3b) folding the negative tab to wrap the negative tab around the separator, the fold of the negative tab coincides with the fold of the separator, and rolling to obtain the positive-separator-negative composite structure.

4. The production method according to claim 3, characterized by, The step 3) further comprises: 3c) winding or folding the positive-separator-negative composite structure to obtain a battery cell.

5. The preparation method according to claim 4, characterized in that, The step 3) further comprises: 3d) placing the battery cell into the negative shell so that the positive tab is higher than the edge of the negative shell; 3e) injecting electrolyte along the diaphragm position, standing, covering the positive shell and pressing the seal, obtaining the full tab button cell.

6. The production method according to claim 5, characterized by, Step 3d) specifically comprises: placing the cell into the negative shell, making the positive tab higher than the edge of the negative shell, and the exposed height of the positive tab is not greater than the length of the white space of the positive tab along the first direction.

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