All-tab battery and preparation method thereof

Abstract

The invention belongs to the technical field of lithium batteries, and particularly relates to a full-tab battery and a preparation method thereof, and the full-tab battery comprises a positive pole piece, a diaphragm, a negative pole piece, a positive shell and a negative shell; the positive pole piece comprises a positive pole current collector and a positive pole active material layer, and a continuous blank area is arranged at the end part of a single side along the length direction of the positive pole current collector, namely a first direction; positive active material layers are arranged on the upper surface and the lower surface of the positive current collector 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 electrode active material layer and greater than 0; the thickness direction of the positive current collector is a first direction, the thickness direction of the positive current collector is a second direction, the diaphragm is folded along the second direction and wraps the surface of the positive pole piece except the blank side, the negative pole piece is folded along the same direction as the diaphragm and wraps the diaphragm, and the end part of the negative pole piece shrinks inwards relative to the diaphragm in the first direction. The structure is simple and compact, the process is simple, and the space utilization rate can be increased.

Description

[0001] This application is a divisional application of the prior application with patent application number 2024100390913, and invention name “A full-ear battery and its preparation method”, which was submitted by the applicant to the State Intellectual Property Office of China on January 11, 2024. Technical Field

[0002] The present invention belongs to the technical field of lithium batteries, and in particular relates to a full-tab battery and a preparation method thereof. Background Art

[0003] The full-ear structure is an effective means to reduce the internal resistance of the battery and improve the battery rate performance. Traditional full-ear batteries usually require a larger blank current collector to be reserved, and the full-ear is prepared by punching, flattening, reserving empty slots, welding busbars or designing other complex structures. The batteries prepared in this way have problems such as reduced electrode coating area, reduced battery capacity, low injection efficiency, increased short circuit risk, complex cell structure and low production efficiency.

[0004] Patent document CN111244381A discloses a full-pole ear button battery and a manufacturing method thereof, wherein the button battery comprises a shell and a cylindrical winding core formed by winding a positive electrode sheet, a separator and a negative electrode sheet; the preparation method comprises: stacking the positive electrode, the separator and the negative electrode in sequence, with the narrow edges of the positive and negative blank foils on both sides, and forming a cylindrical winding core by winding; then compacting the narrow edges of the blank foils at both ends of the winding core respectively to form full-pole ears of 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 battery by conductive metal sheets; filling the positive and negative electrode shells with insulating sealant to form a complete button battery. However, the button battery design requires reserved welding space, which reduces space utilization and makes it difficult to weld the lithium metal negative electrode. After compacting and welding the entire ear, the electrolyte is difficult to infiltrate, the injection efficiency is low, and it is easy to cause electrolyte loss. At the same time, redundant diaphragm width must be reserved to cover the edge of the electrode, otherwise micro-short circuits are likely to occur, reducing space utilization and yield rate.

[0005] Patent document CN111725552A discloses a button battery and a manufacturing method thereof, wherein the button battery comprises a winding body, a current collecting disk and a shell, wherein the winding body and the current collecting disk are both located in the shell, and the winding body is connected to the current collecting disk; the winding body comprises: 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, a part of the positive electrode sheet forms a positive electrode ear, a part of the negative electrode sheet forms a negative electrode ear, and both the positive electrode ear and the negative electrode ear are full ears. The manufacturing method of the button battery is used to manufacture the above-mentioned button battery. The button battery can achieve a relatively low internal resistance while maintaining a relatively high energy density. However, the button battery needs to reserve welding space and add a current collecting plate, 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 diaphragm width to cover the edge of the electrode, otherwise micro-short circuits are likely to occur, reducing space utilization and yield rate.

[0006] Patent document CN116154317A discloses a full-ear cylindrical lithium battery, including a winding core, one end of which is provided with a positive ear, and the other end of which is provided with a negative ear; the end face of the positive ear and / or the negative ear includes: a flattened area after flattening treatment, and a non-flattened area that has not been flattened to provide a gap for electrolyte penetration. Compared with the traditional method of flattening all the end faces of the ear, this patent document can use the gaps between the layers in the non-flattened area to form a circulation channel for the electrolyte, which is convenient for the electrolyte to penetrate into the winding core more quickly in the subsequent injection process, shorten the injection time, and greatly improve the production efficiency. However, the design of the non-flattened area will increase the internal resistance of the battery, especially affect the discharge performance of batteries with small diameter specifications, and increase the difficulty of manufacturing. The battery needs to reserve redundant diaphragm width to cover the edge of the pole piece, otherwise micro-short circuits are prone to occur, reducing space utilization and yield rate.

[0007] Patent document CN115602932A discloses a full-ear core and a lithium-ion battery thereof, which includes a core body, both end faces of the core body are recessed inward to form a guide cavity for exhaust and liquid seepage; the lithium-ion battery includes the full-ear core as described above; the guide cavity increases the surface area of ​​the two end faces of the core body, and the exhaust surface of the core body is increased, thereby improving the exhaust performance of the core body, making the exhaust process of the core body more smooth, so as to improve the safety of use, and at the same time, the guide cavity increases the contact area between the core body and the electrolyte, and the electrolyte is easier to penetrate into the core body, thereby improving the injection efficiency. However, the battery guide cavity is complex to manufacture, and requires additional grooving, which reduces the full-ear area and increases the internal resistance; at the same time, the guide cavity design will reduce the area of ​​the pole piece coating area, causing the battery capacity to decrease.

[0008] In summary, the full-ear structure battery in the prior art has the defects of complex preparation process and easy short circuit, and the coating area of ​​the pole piece in the prior art is small, resulting in reduced battery capacity, low injection efficiency and low production efficiency. Summary of the invention

[0009] In order to improve the deficiencies of the prior art, the present invention provides a full-tab battery and a preparation method thereof. Specifically, the present invention provides the following technical solutions:

[0010] A full-tab battery, the battery comprising a positive electrode sheet, a separator, a negative electrode sheet and a positive and negative electrode shell, wherein the positive electrode sheet, the separator and the negative electrode sheet are located inside the positive and negative electrode shells;

[0011] The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer, and a continuous blank area is provided at a single end along the length direction of the positive electrode current collector, i.e., the first direction, and the positive electrode active material layer is provided on the upper and lower surfaces of the positive electrode current collector 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 electrode active material layer and greater than 0;

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

[0013] The separator is folded in half along the second direction and wrapped around the surface of the positive electrode sheet except the blank side;

[0014] The negative electrode sheet is folded in the same direction as the separator to wrap around the separator, and the end of the negative electrode sheet is retracted relative to the separator in a first direction;

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

[0016] The present invention also provides a method for preparing the above-mentioned full-tab battery, the method comprising the following steps:

[0017] 1) preparing a positive electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode active material layer, a continuous blank area being provided at a single end along a first direction of the positive electrode current collector, and a positive electrode active material layer being provided at a portion of the positive electrode current collector other than the blank area; a length of the blank area along the first direction being less than or equal to 150% of a thickness of the positive electrode active material layer and greater than 0;

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

[0019] 3) Assembling the positive electrode separator and negative electrode composite structure, the blank area forms a positive electrode full tab electrically connected to the positive electrode shell, and the area where the negative electrode sheet is electrically connected to the negative electrode shell forms a negative electrode full tab, to obtain the full tab battery.

[0020] According to the present invention, the step of assembling the positive electrode separator negative electrode composite structure specifically includes:

[0021] 3a) folding the separator and wrapping the separator around the positive electrode sheet, with the separator fold coinciding with the non-blank side edge of the positive electrode sheet, to obtain a positive electrode separator composite structure;

[0022] 3b) Folding the negative electrode sheet, wrapping the negative electrode sheet around the separator, aligning the fold of the negative electrode sheet with the fold of the separator, and rolling to obtain a positive electrode separator negative electrode composite structure.

[0023] The technology of the present invention has the following beneficial effects:

[0024] 1. The width of the positive electrode blank in the present invention is less than or equal to 150% of the thickness of the positive electrode material layer, and after the battery cell is placed in the shell, the positive electrode sheet is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode sheet is not greater than the width of the positive electrode sheet blank; at the same time, the negative electrode sheet is covered with active material on one side or uses metal as the negative electrode, and the negative electrode sheet is folded to form a negative electrode full-pole ear electrically connected to the negative electrode shell. Therefore, the active material area of ​​the electrode sheet in the present invention makes full use of the height space in the battery shell, which can effectively increase the battery capacity compared to the traditional full-pole ear battery structure.

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

[0026] 2. The diaphragm of the present invention completely covers the positive electrode active material area, the negative electrode sheet shrinks relative to the diaphragm, and a positive electrode diaphragm negative electrode composite structure is formed by rolling, thereby preventing the electrode sheet from shifting and reducing the risk of short circuit during winding, lamination and sealing.

[0027] 3. The diaphragm of the present invention completely covers the positive electrode active material area, the width of the positive electrode blank is not more than 150% of the thickness of the positive electrode material layer, and the negative electrode pole piece is retracted relative to the diaphragm, so that the negative electrode cannot be shifted in the width direction, thereby reducing the risk of short circuit caused by the positive electrode blank falling or bending during the compaction of the positive electrode full ear. At the same time, the present invention adopts a structure in which a folded diaphragm is used to cover the positive electrode pole piece, which reduces the risk of short circuit caused by positive electrode burrs and pole piece displacement.

[0028] 4. The present invention adopts a copper foil or metal negative electrode structure with negative electrode active material covered on one side, and utilizes the negative electrode fold and the negative electrode metal blank around the battery core to contact with the negative electrode shell to form a negative electrode full ear, thereby simplifying the negative electrode full ear flattening process; the present invention compacts and forms the positive electrode full ear while sealing the battery, and does not require additional flattening mechanism and flattening process, thereby improving battery production efficiency and reducing equipment and labor investment; the present invention compacts the positive electrode full ear after liquid injection, and the liquid injection efficiency is high, and there is no need to reserve electrolyte penetration holes, exhaust holes, etc., thereby simplifying the pole piece design and improving space utilization.

[0029] One end face of the battery cell of the present invention is blank for the positive electrode plate, and the other end faces are blank for the negative electrode metal. The negative electrode plate is in full contact with at least two sides of the negative electrode shell, which increases the negative electrode current collecting area, is beneficial to reducing internal resistance, promoting heat dissipation, and improving battery rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a cross-sectional view of the positive electrode separator and negative electrode composite structure in the full-ear battery in Example 1;

[0031] Figure 2 It is a cross-sectional view of the positive electrode separator and negative electrode composite structure in the full-ear battery in Example 2;

[0032] Figure 3 This is a cross-sectional view of the positive electrode, separator and negative electrode stacking structure in the full-ear battery in Comparative Example 1.

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

[0034] [Full-tab battery]

[0035] As mentioned above, the present invention provides a full-tab battery, the battery comprising a positive electrode sheet, a separator, a negative electrode sheet and a positive and negative electrode shell, wherein the positive electrode sheet, the separator and the negative electrode sheet are located inside the positive and negative electrode shells;

[0036] The positive electrode sheet comprises 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 remaining part 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 in half along the width direction and wrapped around the positive electrode sheet, and the separator fold coincides with the non-blank side edge of the positive electrode sheet;

[0038] The negative electrode sheet is folded in half along the width direction to wrap around the separator, and the fold of the negative electrode sheet coincides with the fold of the separator;

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

[0040] According to the embodiment of the present invention, the present invention adopts a structure in which a folded diaphragm is used to cover the positive electrode pole piece, thereby reducing the risk of short circuit caused by positive electrode burrs and pole piece displacement.

[0041] According to an embodiment of the present invention, the end of the negative electrode sheet is retracted relative to the end of the diaphragm. In the present invention, the negative electrode sheet is a folded structure covering the diaphragm, and the folded negative electrode sheet is retracted relative to the diaphragm, so that the negative electrode sheet cannot be displaced in the width direction, thereby reducing the risk of short circuit during the compaction of the full lug. Secondly, the diaphragm of the present invention completely covers the positive electrode active material area, the width of the positive electrode blank area is not more than 150% of the thickness of the positive electrode active material layer, and the negative electrode sheet is retracted relative to the diaphragm, thereby reducing the risk of short circuit caused by the positive electrode blank lodging or bending during the compaction of the positive full lug.

[0042] According to an embodiment of the present invention, the width of the blank area is less than or equal to 120% of the thickness of the positive electrode active material layer and greater than 0. Preferably, the width of the blank area is less than or equal to 100% of the thickness of the positive electrode active material layer and greater than 0.

[0043] According to an embodiment of the present invention, the negative electrode plate is a metal plate or a plate including a negative electrode current collector and a negative electrode active material layer.

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

[0045] According to the present invention, when the negative electrode plate is a plate comprising a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is located on one side surface of the negative electrode current collector and is connected to the diaphragm, and the negative electrode current collector is connected to the negative electrode shell; the positive electrode plate is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode plate is not greater than the length of the blank area of ​​the positive electrode plate along the first direction.

[0046] According to the present invention, the positive electrode sheet, separator and negative electrode sheet are a positive electrode-separator-negative electrode composite structure, and the positive electrode-separator-negative electrode composite structure can be directly used as a battery cell, or formed into a battery cell after winding or folding; the battery cell includes several end faces, one of which is a blank area of ​​the positive electrode sheet, i.e., a positive electrode full lug, and the other end faces are negative electrode sheets, i.e., negative electrode full lugs.

[0047] According to an embodiment of the present invention, the positive electrode sheet, the separator and the negative electrode sheet are a positive electrode separator negative electrode composite structure, wherein the separator is folded in half along the width direction and wrapped around the positive electrode sheet, and the separator fold coincides with the non-blank side edge of the positive electrode sheet; the negative electrode sheet is folded in half along the width direction and wrapped around the separator, and the negative electrode sheet fold coincides with the separator fold; the composite structure can be directly used as a battery cell, or formed into a battery cell after winding or folding; the battery cell includes several end faces, one of which is the blank area of ​​the positive electrode sheet, that is, the positive full pole ear, and the other end faces are negative electrode sheets (if it is a metal electrode sheet, the end face is the electrode sheet; if it is a electrode sheet including a negative electrode current collector and a negative electrode active material layer, the end face is the negative electrode current collector), that is, the negative electrode full pole ear. In the present invention, the active material area of ​​the electrode sheet makes the best use of the height space in the battery shell. Compared with the traditional full pole ear battery structure, the present invention can effectively improve the battery capacity.

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

[0049] According to an embodiment of the present invention, the retracted width of the negative electrode pole piece is smaller than the width of the positive electrode blank area, and preferably the retracted width of the negative electrode pole piece is 5% to 50% of the width of the positive electrode blank area.

[0050] According to an embodiment of the present invention, 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, such as carbon-coated aluminum foil.

[0051] According to an embodiment of the present invention, the width of the positive electrode current collector is the height of the battery shell + (0.2mm to 5mm). In the present invention, there is no special restriction on the length of the positive electrode current collector, as long as it can form the required size requirements of the battery cell; for example, for a 0962 type button battery, when the diameter of the battery 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 an embodiment of the present invention, the positive electrode active material is at least one selected from carbon fluoride, manganese dioxide, lithium iron phosphate, lithium cobalt oxide, and lithium nickel cobalt manganese oxide, for example, carbon fluoride.

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

[0054] According to an embodiment of the present invention, the diaphragm 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, a polypropylene composite polyethylene diaphragm with ceramic coating.

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

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

[0057] According to an embodiment of the present invention, the width of the metal pole piece is the width of the diaphragm minus the width of the positive electrode blank area*(5% to 50%), and the thickness is 30 μm to 150 μm.

[0058] According to an embodiment of the present invention, the negative electrode plate is selected from a plate comprising a negative electrode current collector and a negative electrode active material layer, which is a metal negative electrode structure in which a negative electrode current collector is covered with a negative electrode active material layer on one side.

[0059] According to an embodiment of the present invention, 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 invention, the negative electrode active material is selected from one of silicon carbon, graphite and lithium titanate.

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

[0062] [Preparation of full-tab battery]

[0063] As mentioned above, the present invention also provides a method for preparing the above-mentioned full-tab battery, which comprises the following steps:

[0064] 1) preparing a positive electrode sheet, the positive electrode sheet comprising 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 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;

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

[0066] 3) Assembling the positive electrode separator and negative electrode composite structure, the blank area forms a positive electrode full tab electrically connected to the positive electrode shell, and the area where the negative electrode sheet is electrically connected to the negative electrode shell forms a negative electrode full tab, to obtain the full tab battery.

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

[0068] 3a) folding the separator and wrapping the separator around the positive electrode sheet, with the separator fold coinciding with the non-blank side edge of the positive electrode sheet, to obtain a positive electrode separator composite structure;

[0069] 3b) folding the negative electrode sheet, wrapping the negative electrode sheet around the separator, aligning the fold of the negative electrode sheet with the fold of the separator, and rolling to obtain a positive electrode separator negative electrode composite structure.

[0070] According to the present invention, the step 3) further comprises:

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

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

[0073] 3c) The positive electrode separator and negative electrode composite structure is wound or folded to obtain a battery cell, wherein the battery cell includes a plurality of end faces, wherein one end face is a blank area of ​​the positive electrode sheet, i.e., a positive electrode full tab, and the other end faces are negative electrode sheets, i.e., negative electrode full tabs.

[0074] According to the present invention, the step 3) further comprises:

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

[0076] 3e) Inject liquid along the diaphragm, let it stand, cover it with the positive electrode shell and press it tightly to obtain a full-tab battery.

[0077] According to an embodiment of the present invention, step 3a) specifically comprises:

[0078] The diaphragm is folded in half along the width direction, the projection of the diaphragm coincides with the positive electrode material area on the positive electrode plate, the projection width of the diaphragm on the positive electrode blank area is less than or equal to 1 / 4 of the width of the blank area, and the crease of the diaphragm coincides with the crease of the positive electrode plate, to obtain a positive electrode diaphragm composite structure.

[0079] According to an embodiment of the present invention, step 3b) specifically includes: folding the negative electrode sheet in half along the width direction, the projection of the negative electrode sheet overlaps with the projection area of ​​the diaphragm and shrinks inward, the width of the shrinkage is less than or equal to the width of the blank area, the fold of the diaphragm overlaps with the fold of the negative electrode sheet, the negative electrode active material area overlaps with the diaphragm, and a positive electrode diaphragm-negative electrode composite structure is obtained by rolling.

[0080] According to the present invention, step 3b) specifically includes: folding the negative electrode sheet in half along the second direction, the projection of the negative electrode sheet overlaps with the projection area of ​​the diaphragm and shrinks inward, the width of the shrinkage is less than or equal to the width of the blank area, the fold of the diaphragm overlaps with the fold of the negative electrode sheet, the negative electrode active material area overlaps with the diaphragm, and a positive electrode diaphragm-negative electrode composite structure is obtained by rolling.

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

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

[0083] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0084] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] The following will further describe the full-tab battery and its preparation method of the present invention in detail in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention, and should not be interpreted as limiting the scope of protection of the present invention. All technologies realized based on the above content of the present invention are included in the scope of protection of the present invention.

[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 6 mm and an inner cavity diameter of 8.8 mm, comprising the following steps: 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 collector 1, and 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 collector 1 along the length direction. The specific selection of the positive electrode active material 2 is set according to actual needs. In this embodiment, carbon fluoride is selected as the positive electrode active material 2. There is a blank area 6 at one end of the positive electrode collector 1 in the length direction, and the width of the blank area 6 is 0.4 mm. The positive electrode collector 1 coated with the positive electrode active material 2 forms a positive electrode sheet; a diaphragm 3 with a width of 12.6 mm and a thickness of 12 μm is folded in half along the width direction, and the diaphragm 3 is coated on the positive electrode active material 2, and the fold of the diaphragm 3 coincides with the non-blank side edge of the positive electrode 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 coated on the diaphragm 3, and the fold of the negative electrode sheet 4 coincides with the fold of the diaphragm. The specific selection of the negative electrode plate 4 is set according to actual needs, and can be a metal material or a non-metal material. In this embodiment, metallic lithium is selected as the negative electrode plate 4.

[0089] The positive electrode separator and negative electrode composite structure is obtained by roller pressing, and 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 the negative electrode shell, and the Beijing Chemical Reagent Institute 012 electrolyte is injected. The battery cell is allowed to stand at room temperature and vacuum for 10 minutes, and then the positive electrode shell is covered and hydraulically sealed to obtain a full-ear battery.

[0090] The yield rate of the full-ear button battery prepared in this embodiment is more than 95%. Compared with the traditional full-ear battery, the width of the positive electrode active area (the width of the positive electrode material) of the full-ear button battery prepared in this embodiment is increased by more than 20%. The average internal resistance of the full-ear button battery prepared in this embodiment is 5 ohms, the discharge capacity at room temperature 1C is greater than or equal to 50mAh, and the discharge capacity at -20℃ 0.01C 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 6 mm and an inner cavity diameter of 8.8 mm, comprising the following steps: 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 electrode current collector 1, and a positive electrode active material 2 with a width of 5.9 mm and a thickness of 200 μm is coated on both sides of the positive electrode current collector 1 along the length direction. The specific selection of the positive electrode active material 2 is set according to actual needs. In this embodiment, lithium nickel cobalt manganese oxide is selected. There is a blank area 6 in the length direction of the positive electrode current collector 1, and 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 with a width of 12.6 mm and a thickness of 12 μm is used. 3 is folded in half along the width direction, and the separator 3 is coated on the positive electrode active material 2, and the fold of the separator 3 coincides with the non-blank side edge of the positive current collector 1; a negative electrode active material layer 5 with a thickness of 400 μm is coated on one side of a copper foil (i.e., the negative electrode current collector 4') with a width of 12.3 mm and a thickness of 6 μm. In this embodiment, the negative electrode active material layer 5 is formed by coating with a silicon-carbon negative electrode material, and the copper foil (i.e., the negative electrode current collector 4') provided with the negative electrode active material layer 5 is used as the negative electrode plate; the negative electrode plate is folded in half and coated on the separator 3, and the fold of the negative electrode plate coincides with the fold of the separator 3. The positive electrode separator negative electrode composite structure is obtained by roller shaping, and 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 electrode shell, and commercial silicon-carbon electrolyte is injected, and the battery cell is left to stand for 10 minutes in vacuum at room temperature, and the positive electrode shell is covered and hydraulically sealed to obtain a full-ear battery.

[0093] The yield rate of the full-pole ear button battery prepared in this embodiment is over 95%. Compared with the traditional full-pole ear battery, the width of the positive electrode active area of ​​the full-pole ear button battery prepared in this embodiment is increased by more than 20%.

[0094] Example 3

[0095] A full-tab battery comprises a positive electrode current collector 1, a separator 3, a negative electrode pole piece and positive and negative electrode shells. The positive electrode current collector 1, the separator 3 and the negative electrode pole piece are located inside the positive and negative electrode shells.

[0096] The positive electrode current collector 1 is bent into a folded structure, and the outer surface of the positive electrode current collector 1 is provided with a positive electrode active material layer 2 and a blank area 6, and the blank area 6 is located at the end of the positive electrode current collector 1 away from the fold; the width of the blank area 6 is less than or equal to 150% of the thickness of the positive electrode active material 2; the diaphragm 3 is folded and wrapped around the outside of the positive electrode active material 2, the fold of the diaphragm 3 overlaps with the fold of the positive electrode current collector 1, and the end of the diaphragm 3 is located between the end of the positive electrode current collector 1 and the end of the positive electrode active material 2; the negative electrode sheet wraps around the diaphragm 3, the fold of the negative electrode sheet overlaps with the fold of the diaphragm 3, the end of the negative electrode sheet is retracted relative to the end of the diaphragm 3, and the retracted width of the negative electrode sheet is less than the width of the blank area 6.

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

[0098] In this embodiment, the end of the negative electrode sheet 4 away from the fold is a blank portion 7, and the fold of the negative electrode sheet and the blank portion 7 of the negative electrode sheet are electrically connected to the negative electrode shell. The folded negative electrode sheet is retracted relative to the diaphragm 3, so that the negative electrode sheet cannot be shifted in the width direction, thereby reducing the risk of short circuit during the compaction of the full ear.

[0099] The positive electrode current collector 1, the separator 3, and the negative electrode sheet are folded to form a battery cell, which includes several end faces, one of which is a blank area 6 of the positive electrode current collector 1, and the other end faces are folds or blank portions 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 electrode 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 foamed aluminum, 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; the width of the negative electrode plate is 12.3 mm and the thickness is 60 μm.

[0101] Comparative Example 1

[0102] This comparative example provides a method for preparing a conventional full-tab battery with an inner cavity height of 6 mm and an inner cavity diameter of 8.8 mm, comprising the following steps: 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, and 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 the length direction. In this comparative example, carbon fluoride is selected as the positive electrode active material, and there is a blank area at one end of the length direction of the positive electrode current collector, and the width of the blank area is 0.5 mm. The positive electrode current collector coated with the positive electrode active material forms a positive electrode sheet; two layers of diaphragms 3 with a width of 5.3 mm and a thickness of 12 μm are respectively coated on the positive electrode active material, and the positive electrode blank area is exposed 0.3 mm; 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 diaphragm, and the negative electrode sheet is retracted 0.3 mm relative to the diaphragm on the positive electrode blank area side. In this comparative example, metal lithium is selected as the negative electrode sheet.

[0103] The above-mentioned positive electrode separator negative electrode stacking structure is wound with the negative electrode as the inner layer of the winding core to obtain a battery cell with an outer envelope diameter of 8.8 mm. The positive and negative electrode full ears are flattened respectively, and the battery cell is placed in the negative electrode shell, and the Beijing Chemical Reagent Research Institute 012 type electrolyte is injected. The battery cell is allowed to stand at room temperature and vacuum for 10 minutes, and the positive electrode shell is covered and hydraulically sealed to obtain a traditional full-ear battery.

[0104] The yield rate of the full-pole ear button battery prepared in this comparative example is 80%, the average internal resistance of the full-pole ear button battery prepared in this comparative example is 8 ohms, the average discharge capacity at room temperature 1C is 38 mAh, and the average discharge capacity at -20℃0.01C is 29 mAh.

[0105] The above examples are used to illustrate the specific implementation of the present invention. However, the protection scope of the present invention is not limited to the above exemplary implementation. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A full-tab battery, comprising a positive electrode sheet, a separator, a negative electrode sheet and a positive and negative electrode shell, wherein the positive electrode sheet, the separator and the negative electrode sheet are located inside the positive and negative electrode shells; characterized in that: The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer, and a continuous blank area is provided at a single end along the length direction of the positive electrode current collector, i.e., the first direction, and the positive electrode active material layer is provided on the upper and lower surfaces of the positive electrode current collector 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 electrode active material layer and greater than 0; The thickness direction of the positive electrode current collector is the second direction; The separator is folded in half along the second direction and wrapped around the surface of the positive electrode sheet except the blank side; The negative electrode sheet is folded in the same direction as the separator to wrap around the separator, and the end of the negative electrode sheet is retracted relative to the separator in a first direction; The area where the negative electrode plate is electrically connected to the negative electrode shell forms a negative electrode full tab, and the blank area forms a positive electrode full tab electrically connected to the positive electrode shell.

2. The full-tab battery according to claim 1, characterized in that: The negative electrode plate is a metal plate or a plate including a negative electrode current collector and a negative electrode active material layer.

3. The full-tab battery according to claim 2, characterized in that: When the negative electrode plate is a plate comprising a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is located on one side surface of the negative electrode current collector and is connected to the diaphragm, and the negative electrode current collector is connected to the negative electrode shell; the positive electrode plate is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode plate is not greater than the length of the blank area of ​​the positive electrode plate along the first direction.

4. The full-tab battery according to any one of claims 1 to 3, characterized in that: The positive electrode sheet, separator and negative electrode sheet are a positive electrode, separator and negative electrode composite structure, and the positive electrode, separator and negative electrode composite structure can be directly used as a battery cell, or formed into a battery cell after winding or folding; the battery cell includes several end faces, one of which is a blank area of ​​the positive electrode sheet, i.e., a positive electrode full lug, and the other end faces are negative electrode sheets, i.e., negative electrode full lugs.

5. A method for preparing a full-tab battery according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: 1) preparing a positive electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode active material layer, a continuous blank area being provided at a single end along a first direction of the positive electrode current collector, and a positive electrode active material layer being provided at a portion of the positive electrode current collector other than the blank area; a length of the blank area along the first direction being less than or equal to 150% of a thickness of the positive electrode active material layer and greater than 0; 2) preparing a separator, a negative electrode sheet, a positive electrode shell and a negative electrode shell; 3) Assembling the positive electrode separator negative electrode composite structure, the blank area forms a positive electrode full tab electrically connected to the positive electrode shell, and the area where the negative electrode sheet is electrically connected to the negative electrode shell forms a negative electrode full tab, to obtain the full tab battery; The steps of assembling the positive electrode separator negative electrode composite structure include: 3a) folding the separator and wrapping the separator around the positive electrode sheet, with the separator fold coinciding with the non-blank side edge of the positive electrode sheet, to obtain a positive electrode separator composite structure; 3b) Folding the negative electrode sheet, wrapping the negative electrode sheet around the separator, aligning the fold of the negative electrode sheet with the fold of the separator, and rolling to obtain a positive electrode separator negative electrode composite structure.

6. The preparation method according to claim 5, characterized in that: The step 3) also includes: 3c) Winding or folding the positive electrode separator and negative electrode composite structure to obtain a battery cell.

7. The preparation method according to claim 6, characterized in that: The step 3) also includes: 3d) placing the battery cell into the negative electrode casing so that the positive electrode sheet is higher than the edge of the negative electrode casing; 3e) Inject liquid along the diaphragm, let it stand, cover it with the positive electrode shell and press it tightly to obtain a full-tab battery.

8. The preparation method according to any one of claims 5 to 7, characterized in that: Step 3a) specifically includes: The diaphragm is folded in half along the width direction, the projection of the diaphragm coincides with the positive electrode material area on the positive electrode plate, the projection width of the diaphragm on the positive electrode blank area is less than or equal to 1 / 4 of the width of the blank area, and the crease of the diaphragm coincides with the crease of the positive electrode plate, to obtain a positive electrode diaphragm composite structure.

9. The preparation method according to any one of claims 5 to 7, characterized in that: Step 3b) specifically includes: folding the negative electrode sheet in half along the second direction, the projection of the negative electrode sheet overlaps with the projection area of ​​the diaphragm and shrinks inward, the width of the shrinkage is less than or equal to the width of the blank area, the fold of the diaphragm overlaps with the fold of the negative electrode sheet, the negative electrode active material area overlaps with the diaphragm, and rolling is performed to obtain a positive electrode diaphragm negative electrode composite structure.

10. The preparation method according to claim 7, characterized in that: Step 3d) specifically includes: placing the battery cell into the negative electrode shell, so that the positive electrode sheet is higher than the edge of the negative electrode shell, and the exposed height of the positive electrode sheet is not greater than the length of the blank area of ​​the positive electrode sheet along the first direction.

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