Cylindrical battery, preparation method thereof and power utilization device

Abstract

The invention discloses a cylindrical battery, a preparation method thereof and an electric device, and relates to the technical field of cylindrical batteries. According to the invention, a groups of first tab regions are formed at the first end of the roll core, and each group of first tab regions is provided with a plurality of positive tabs arranged along the radial direction of the roll core; b groups of second tab regions are formed at the second end of the roll core, and a plurality of negative tabs arranged along the radial direction of the roll core are arranged on each group of second tab regions. Compared with a full tab technology, the number of tabs can be greatly reduced, the tab die cutting number is reduced, the working procedure is optimized, and the production efficiency is improved; and the gap between the roll core and the collector plate can be enlarged, so that the circulation of electrolyte is facilitated, and the infiltration effect of the electrolyte of the pole piece can be improved. Compared with a conventional multi-tab technology, the number of tabs on the pole piece can be effectively increased, so that the tabs are dispersed on the whole pole piece, electron transmission in the charging and discharging process of the battery is facilitated, the overcurrent capacity of the battery is improved, the overcurrent temperature rise of the battery is reduced, and the internal resistance of the battery can also be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of cylindrical batteries, and in particular to a cylindrical battery, a preparation method thereof and an electrical device. Background Art

[0002] The 46 series large cylindrical battery is widely used in the field of power batteries due to its high energy density and high safety. Currently, there are two main types of cylindrical batteries: full-pole ear technology or multi-pole ear technology:

[0003] (1) Full-tab technology

[0004] At present, most large cylindrical power batteries adopt a full-ear design (or called no-ear design), in which all the ears are cut, bent, and stacked in an interlaced manner, and then electrically connected to the collector plate or battery housing. Cutting, bending, and stacking all the ears inevitably affects production efficiency, and the densely stacked ears also hinder the flow of electrolyte inside the battery, affecting the infiltration effect of the electrode in the electrolyte.

[0005] (2) Multi-electrode technology

[0006] In order to reduce costs and improve production efficiency, it is often used to lead out several tabs from the pole piece and electrically connect them to the collector plate or battery housing. In conventional multi-tab technology, the tabs are usually welded out from the pole piece foil, and the number of tabs is within 10. Due to the limitation of the tab lead-out method and number, the battery's current capacity is limited and the internal resistance is large, which limits the application scope of large cylindrical batteries.

[0007] Therefore, there is an urgent need to improve the way the tabs are led out, solve the problems existing in full tab technology and multi-tab technology, and expand the application scenarios of large cylindrical batteries.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The object of the present invention is to provide a cylindrical battery, a preparation method thereof and an electrical device, aiming to solve the problems existing in full-electrode-tab technology and / or multi-electrode-tab technology and improve the electrochemical performance of the battery.

[0010] The present invention is achieved in that:

[0011] In a first aspect, the present invention provides a cylindrical battery, comprising a winding core, the winding core comprising a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprising a positive electrode active material region and a plurality of positive electrode tabs connected to one side of the positive electrode active material region and arranged at intervals, the negative electrode sheet comprising a negative electrode active material region and a plurality of negative electrode tabs connected to one side of the negative electrode active material region and arranged at intervals;

[0012] The winding core has a first end and a second end opposite to the first end, the plurality of positive electrode tabs are all located at the first end of the winding core, and the plurality of negative electrode tabs are all located at the second end of the winding core;

[0013] A group of first tab regions is provided at the first end of the winding core, and each group of first tab regions has a plurality of positive tabs arranged along the radial direction of the winding core;

[0014] A group b of second pole tab regions are arranged at the second end of the winding core, and each group of second pole tab regions has a plurality of negative pole tabs arranged along the radial direction of the winding core.

[0015] In an optional implementation, a and b satisfy: 1≤a≤20, 1≤b≤20;

[0016] Preferably, 3≤a≤8, 3≤b≤8.

[0017] In an optional embodiment, the winding core is formed by winding a positive electrode sheet, a negative electrode sheet and two layers of separators, and the total number of positive electrode tabs is m;

[0018] Definition: The winding angle of the first positive electrode tab on the positive electrode sheet is θ m(1) , the winding angle of the a+1th positive electrode tab on the positive electrode sheet is θ m(a+1) , the winding angle of the mth positive electrode tab on the positive electrode sheet is θ m(m) ; The winding angles of the first positive electrode tab and the a+1th positive electrode tab satisfy: θ m(a+1) -θ m(1) =360°;

[0019] On the positive electrode, the distance ΔL1 between any two adjacent tabs x and x+1 on the electrode satisfies:

[0020]

[0021] Where, d ascs It is the sum of the thickness of the positive electrode sheet, the negative electrode sheet and the two layers of separator.

[0022] In an optional embodiment, the winding core is formed by winding a positive electrode sheet, a negative electrode sheet and two layers of separators, and the total number of negative electrode tabs is n;

[0023] Definition: The winding angle of the first negative electrode tab on the negative electrode sheet is θ n(1) , the winding angle of the b+1th negative electrode tab on the negative electrode sheet is θ n(b+1) , the winding angle of the nth negative electrode tab on the negative electrode sheet is θ n(n) ; The winding angles of the first negative electrode tab and the b+1th negative electrode tab satisfy:

[0024] θ n(b+1) -θ n(1)=360°;

[0025] On the negative electrode, the distance ΔL2 between any two adjacent tabs y and y+1 on the electrode satisfies:

[0026]

[0027] Where, d ascs It is the sum of the thickness of the positive electrode sheet, the negative electrode sheet and the two layers of separator.

[0028] In an optional embodiment, the plurality of positive electrode tabs and the plurality of negative electrode tabs are bent;

[0029] Preferably, the plurality of positive electrode tabs and the plurality of negative electrode tabs are all bent toward the center of the winding core.

[0030] In an optional embodiment, a first current collecting disk and a second current collecting disk are further included, the positive electrode tab is electrically connected to the first current collecting disk, and the negative electrode tab is electrically connected to the second current collecting disk.

[0031] In an optional embodiment, the first current collecting disk has a first connecting protrusions, and each first connecting protrusion corresponds to a first pole lug area;

[0032] The second current collecting plate has b second connecting protrusions, and each second connecting protrusion corresponds to a second pole lug area.

[0033] In an optional embodiment, it also includes a shell and a cover plate, the winding core, the first collecting disc and the second collecting disc are all installed in the shell, the first collecting disc is electrically connected to the pole on the cover plate, and the second collecting disc is electrically connected to the shell or the pole.

[0034] In a second aspect, the present invention provides a method for preparing a cylindrical battery according to any one of the aforementioned embodiments, comprising: providing a positive electrode sheet having a plurality of positive electrode tabs, and a negative electrode sheet having a plurality of negative electrode tabs;

[0035] After winding, a winding core is formed. By adjusting the spacing between two adjacent positive electrode tabs and the spacing between two adjacent negative electrode tabs, a group of first tab areas a is formed at the first end of the winding core, and each group of first tab areas has a plurality of positive electrode tabs arranged along the radial direction of the winding core; a group of second tab areas b is formed at the second end of the winding core, and each group of second tab areas has a plurality of negative electrode tabs arranged along the radial direction of the winding core;

[0036] Preferably, the winding angle of the first positive electrode tab on the positive electrode sheet is θ m(1) , the winding angle of the a+1th positive electrode tab on the positive electrode sheet is θ m(a+1) , the winding angle of the mth positive electrode tab on the positive electrode sheet is θ m(m) ; The winding angles of the first positive electrode tab and the a+1th positive electrode tab satisfy: θm(a+1) -θ m(1) =360°;

[0037] The winding angle of the first negative electrode tab on the negative electrode sheet is θ n(1) , the winding angle of the b+1th negative electrode tab on the negative electrode sheet is θ n(b+1) , the winding angle of the nth negative electrode tab on the negative electrode sheet is θ n(n) ; The winding angles of the first negative electrode tab and the b+1th negative electrode tab satisfy: θ n(b+1) -θ n(1) =360°;

[0038] On the positive electrode, the distance ΔL1 between any two adjacent tabs x and x+1 on the electrode satisfies:

[0039]

[0040] On the negative electrode, the distance ΔL2 between any two adjacent tabs y and y+1 on the electrode satisfies:

[0041]

[0042] Where, d ascs It is the sum of the thickness of the positive electrode sheet, the negative electrode sheet and the two layers of separator.

[0043] In a third aspect, the present invention provides an electrical device, comprising a cylindrical battery according to any one of the aforementioned embodiments or a cylindrical battery prepared by the preparation method of the aforementioned embodiments.

[0044] The present invention has the following beneficial effects: the present invention forms a group of first tab regions at the first end of the winding core, each group of first tab regions has a plurality of positive tabs arranged along the radial direction of the winding core; forms a group of second tab regions at the second end of the winding core, each group of second tab regions has a plurality of negative tabs arranged along the radial direction of the winding core. The continuous tabs arranged along the radial direction at both ends of the winding core are convenient for electrical connection, which can significantly reduce the number of electrical connection processes and improve production efficiency.

[0045] It should be noted that compared with the existing full-tab technology for cylindrical batteries, the number of tabs can be greatly reduced, the number of tab die-cutting can be reduced, the process can be optimized, and the production efficiency can be improved; the gap between the winding core and the collecting plate can be increased, which is beneficial to the circulation of electrolyte and can improve the wetting effect of the electrode electrolyte.

[0046] Compared with conventional multi-electrode technology, it can effectively increase the number of pole ears on the pole piece, so that the pole ears are dispersed on the entire pole piece, which is beneficial to the transmission of electrons during the battery charging and discharging process, improves the battery's overcurrent capacity, reduces the battery's overcurrent temperature rise, and can also reduce the battery's internal resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 Schematic diagram of a cylindrical battery;

[0049] Figure 2 is a schematic diagram of a positive electrode;

[0050] Figure 3 is a schematic diagram of a negative electrode;

[0051] Figure 4 Schematic diagram of winding angle of winding core tab;

[0052] Figure 5 It is a schematic diagram of the winding core;

[0053] Figure 6 Schematic diagram of the collecting plate.

[0054] Icon: 100-cylindrical battery; 110-winding core; 111-positive electrode plate; 112-negative electrode plate; 1111-positive electrode active material area; 1112-positive electrode tab; 1121-negative electrode active material area; 1122-negative electrode tab; 113-first tab area; 120-first current collecting disk; 121-first connecting protrusion; 130-second current collecting disk. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0056] The embodiment of the present invention provides a cylindrical battery 100, such as Figure 1 As shown, it includes a winding core 110, a first current collecting disk 120, and a second current collecting disk 130. One end of the winding core 110 is provided with a plurality of positive pole tabs 1112, and the other end of the winding core 110 is provided with a plurality of negative pole tabs 1122. The positive pole tab 1112 is electrically connected to the first current collecting disk 120, and the negative pole tab 1122 is electrically connected to the second current collecting disk 130.

[0057] Please combine Figure 1 , Figure 2 and Figure 3 The winding core 110 is formed by winding a positive electrode sheet 111, a negative electrode sheet 112 and two layers of separators. The positive electrode sheet 111 includes a positive active material area 1111 and a plurality of positive electrode tabs 1112 connected to one side of the positive active material area 1111 and arranged at intervals. The number of positive electrode tabs 1112 is not limited. The negative electrode sheet 112 includes a negative active material area 1121 and a plurality of negative electrode tabs 1122 connected to one side of the negative active material area 1121 and arranged at intervals. The number of negative electrode tabs 1122 is not limited.

[0058] In actual operation, the positive electrode sheet 111 has a foil area in addition to the positive electrode active material area 1111, and a plurality of positive electrode tabs 1112 are cut from the foil area. The negative electrode sheet 112 has a foil area in addition to the negative electrode active material area 1121, and a plurality of negative electrode tabs 1122 are cut from the foil area.

[0059] like Figure 2-Figure 4 As shown, the total number of positive electrode tabs 1112 is m, namely, from the first tab to the mth tab. Definition: Along the winding direction, the winding angle of the first positive electrode tab on the positive electrode sheet 111 is θ m(1) , the winding angle of the second positive electrode tab is θm(2), and the winding angle of the a+1th positive electrode tab on the positive electrode sheet 111 is θ m(a+1) , the winding angle of the mth positive electrode tab on the positive electrode sheet 111 is θ m(m) ; The winding angles of the first positive electrode tab and the a+1th positive electrode tab satisfy: θ m(a+1) -θ m(1) =360°. That is to say, the first positive electrode tab and the a+1th positive electrode tab just overlap, and the winding angles of the two differ by 360 degrees, that is, one winding can be completed after a+1 positive electrode tabs.

[0060] Similarly, the total number of negative electrode tabs 1122 is n, namely, from the first tab to the nth tab. Definition: Along the winding direction, the winding angle of the first negative electrode tab 1122 on the negative electrode sheet 112 is θ n(1) , the winding angle of the second negative electrode tab 1122 is θ n(2) The winding angle of the b+1th negative electrode tab 1122 on the negative electrode sheet 112 is θ n(b+1) The winding angle of the nth negative electrode tab 1122 on the negative electrode sheet 112 is θ n(n) ; The winding angles of the first negative electrode tab 1122 and the b+1th negative electrode tab 1122 satisfy: θ n(b+1) -θ n(1) =360°. That is to say, the first negative electrode tab and the b+1th negative electrode tab just overlap, and the winding angles of the two differ by 360 degrees, that is, one winding can be completed after passing through b+1 negative electrode tabs.

[0061] like Figure 4 As mentioned above, the tab winding angle refers to the angle that the tab is wound around relative to the center, starting from the center. Figure 4 The second pole ear in the circuit is wound around approximately +180 degrees relative to the center, that is, the winding angle is 360+180=540 degrees.

[0062] Due to the control of the winding angle of the positive electrode tab 1112 and the negative electrode tab 1122, as shown in FIG. Figure 1 and Figure 5 As shown, the winding core 110 has a first end and a second end opposite to the first end. Figure 5 Only one end is shown. Multiple positive pole tabs 1112 are located at the first end of the core 110, and multiple negative pole tabs 1122 are located at the second end of the core 110. A group a of first pole tab areas 113 are provided at the first end of the core 110, and each group of first pole tab areas 113 has multiple positive pole tabs 1112 arranged along the radial direction of the core 110. Similarly, a group b of second pole tab areas are provided at the second end of the core 110, and each group of second pole tab areas has multiple negative pole tabs 1122 arranged along the radial direction of the core 110. By providing a continuous pole tab area, the embodiment of the present invention can reduce the number of electrical connection processes and improve production efficiency.

[0063] Specifically, the number of the first tab regions 113 and the second tab regions may be the same or different, and the two may be controlled independently. Figure 5 The case of a=3 is shown. The number of tab regions is not limited to Figure 5 shown.

[0064] Further, a and b satisfy: 1≤a≤20, 1≤b≤20; preferably, 3≤a≤8, 3≤b≤8. The values ​​of a and b may be the same or different, and the two may independently be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, etc.

[0065] Furthermore, if Figure 2 As shown, on the positive electrode sheet 111, the distance ΔL1 between any two adjacent tabs x and x+1 on the sheet satisfies:

[0066]

[0067] Where, d ascs It is the sum of the thickness of the positive electrode sheet 111, the negative electrode sheet 112 and the two layers of separators.

[0068] By precisely controlling the distance ΔL1 between any two adjacent tabs on the electrode sheet, the positive electrode sheet 111 can be wound such that Figure 5As shown, a group of first pole lug regions 113 are formed, and the positive pole lugs in each group of first pole lug regions 113 are arranged in a row along the radial direction.

[0069] Furthermore, if Figure 3 As shown, on the negative electrode sheet 112, the distance ΔL2 between any two adjacent tabs y and y+1 on the electrode sheet satisfies:

[0070]

[0071] Where, d ascs It is the sum of the thickness of the positive electrode sheet 111, the negative electrode sheet 112 and the two layers of separators.

[0072] By precisely controlling the distance ΔL2 between any two adjacent tabs on the pole sheet, after the negative pole sheet 112 is wound, b groups of second tab regions can be formed, and the negative pole tabs of each group of second tab regions are arranged in a row along the radial direction.

[0073] In some embodiments, the plurality of positive electrode tabs 1112 and the plurality of negative electrode tabs 1122 are bent, and may be partially bent outward and partially bent toward the center. In a preferred embodiment, the plurality of positive electrode tabs 1112 and the plurality of negative electrode tabs 1122 are bent toward the center of the winding core 110 to facilitate subsequent electrical connection with the current collecting disk.

[0074] like Figure 5 and Figure 6 As shown, the first current collecting disc 120 has a first connecting protrusions 121, each of which corresponds to a first pole lug area 113, so as to facilitate electrical connection with a group of first pole lug areas 113 through a first connecting protrusion 121. Similarly, the second current collecting disc 130 has b second connecting protrusions (not shown), each of which corresponds to a second pole lug area, so as to facilitate electrical connection with b group of second pole lug areas through b second connecting protrusions. By providing the first connecting protrusions 121 and the second connecting protrusions, the first current collecting disc 120 and the second current collecting disc 130 have sufficient electrical connection areas at the positions corresponding to the pole lugs.

[0075] In some embodiments, a shell and a cover plate are also included, and the winding core 110, the first current collecting disc 120 and the second current collecting disc 130 are all installed in the shell, the first current collecting disc 120 is electrically connected to the pole on the cover plate, and the second current collecting disc 130 is electrically connected to the shell or the pole, where the pole can be another pole, which is different from the pole connected to the first current collecting disc 120. The cover plate is insulated from the pole on the cover plate, and the cover plate and the shell can be electrically connected by peripheral welding to achieve electrical connection between the cover plate and the shell. There is insulation between the cover plate and the pole and the shell, that is, the first current collecting disc 120 and the second current collecting disc 130 are not connected when the external circuit is not connected.

[0076] The embodiment of the present invention provides a method for preparing a cylindrical battery 100, comprising the following steps: providing a positive electrode sheet 111 having a plurality of positive electrode tabs 1112, and a negative electrode sheet 112 having a plurality of negative electrode tabs 1122, such as Figure 2 and Figure 3 After winding, a winding core 110 is formed, and the distance between two adjacent positive electrode tabs 1112 and the distance between two adjacent negative electrode tabs 1122 are adjusted, as shown in FIG. Figure 5 As shown, a group a of first pole lug regions 113 are formed at the first end of the winding core 110, and each group of first pole lug regions 113 has a plurality of positive pole lugs 1112 arranged radially along the winding core 110; a group b of second pole lug regions are formed at the second end of the winding core 110, and each group of second pole lug regions has a plurality of negative pole lugs 1122 arranged radially along the winding core 110.

[0077] The embodiment of the present invention forms continuous tab areas at both the first and second ends of the winding core 110 by regulating the spacing between two adjacent positive tabs 1112 and the spacing between two adjacent negative tabs 1122, thereby reducing the number of electrical connection steps and improving production efficiency.

[0078] Specifically, the description of the winding angles of the tabs on the positive electrode sheet 111 and the negative electrode sheet 112 refers to the above content of the specification, that is, the winding angles of the first positive electrode tab 1112 and the a+1th positive electrode tab 1112 satisfy: θ m(a+1) -θ m(1) =360°; the winding angles of the first negative electrode tab 1122 and the b+1th negative electrode tab 1122 satisfy: θ n(b+1) -θ n(1) =360°. The specific content will not be repeated here.

[0079] In order to achieve the purpose of forming the first electrode tab region 113 of group a and the second electrode tab region of group b, the spacing between two adjacent positive electrode tabs 1112 and the spacing between two adjacent negative electrode tabs 1122 can be controlled as follows:

[0080] On the positive electrode sheet 111, the distance ΔL1 between any two adjacent tabs x and x+1 on the electrode sheet satisfies:

[0081]

[0082] On the negative electrode sheet 112, the distance ΔL2 between any two adjacent tabs y and y+1 on the sheet satisfies:

[0083]

[0084] Where, d ascs It is the sum of the thickness of the positive electrode sheet 111, the negative electrode sheet 112 and the two layers of separators.

[0085] Specifically, the method for preparing the cylindrical battery 100 includes the following steps:

[0086] (1) The positive electrode active material and the negative electrode active material are coated on aluminum foil and copper foil respectively to form the positive electrode sheet 111 or the negative electrode sheet 112. The positive electrode sheet 111 and the negative electrode sheet 112 are both divided into an active material area and a foil area, and the foil area is located on one side of the active material area.

[0087] (2) According to the calculation method of the distance between two adjacent positive electrode tabs 1112 and the distance between two adjacent negative electrode tabs 1122, m and n tabs are cut out from the foil area of ​​the positive electrode sheet 111 and the negative electrode sheet 112, respectively.

[0088] (3) The positive electrode sheet 111, the separator, the negative electrode sheet 112, and the separator are stacked and wound to form a winding core, so that the tabs of the positive electrode sheet 111 and the tabs of the negative electrode sheet 112 are located at the two ends of the winding core respectively.

[0089] (4) Bend the tabs on the positive electrode sheet 111 and the negative electrode sheet 112, optionally toward the center of the winding core.

[0090] (5) The first current collecting plate 120 and the tab on the positive electrode plate 111 , and the second current collecting plate 130 and the tab on the negative electrode plate 112 are welded to form electrical connections.

[0091] (6) The winding core with the first current collecting disc 120 and the second current collecting disc 130 welded is installed in the shell and covered with a cover plate. The first current collecting disc 120 is electrically connected to the pole on the cover plate, and the second current collecting disc 130 is electrically connected to another shell by welding. The cover plate is insulated from the pole on the cover plate, and the cover plate and the shell can be electrically connected by peripheral welding to achieve electrical connection between the cover plate and the shell.

[0092] (7) The shell and the cover are welded to form a battery.

[0093] The embodiment of the present invention further provides an electric device, including the cylindrical battery 100 provided in the embodiment of the present invention, and the cylindrical battery 100 is used to supply power. The specific form of the electric device is not limited.

[0094] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0095] It should be noted that the preparation processes or parameters of the positive electrode sheet, negative electrode sheet, separator, current collecting plate, shell, and cover plate used in the following examples and comparative examples are as follows:

[0096] Positive electrode sheet: Mix the positive electrode active material (lithium iron phosphate), carbon black and PVDF in a mass ratio of 95%:2%:3% and homogenize to obtain positive electrode slurry. Take an aluminum foil with a thickness of 12μm, a length of 5000mm and a width of 75mm, and apply the positive electrode slurry on both sides of the aluminum foil, leaving a foil area with a width of 3mm, and control the surface density to 18mg / cm 2 , and after drying, the positive electrode sheet is obtained.

[0097] Negative electrode sheet: Mix the negative electrode active material (graphite), carbon black, carboxymethyl cellulose CMC, and styrene butadiene latex binder SBR in a mass ratio of 95%: 0.5%: 2%: 2.5%, and homogenize to obtain the negative electrode slurry. Take a copper foil with a thickness of 6μm, a length of 5100mm, and a width of 80mm, and apply the negative electrode slurry on both sides of the copper foil, leaving a foil area with a width of 3mmμm, and control the surface density to 8mg / cm 2 , and after drying, the negative electrode sheet is obtained.

[0098] Separator: Commercially available polypropylene (PP) separator with a thickness of 9 μm.

[0099] Collecting discs (first collecting disc 120 and second collecting disc 130): The first collecting disc 120 is made of aluminum, and the second collecting disc 130 is made of copper. Figure 6 Shape shown.

[0100] Shell: Made of stainless steel, size 46mm*80mm.

[0101] Pole: Made of aluminum.

[0102] Example 1

[0103] This embodiment provides a method for preparing a cylindrical battery, and the specific steps are as follows:

[0104] (1) Providing a positive electrode sheet and a negative electrode sheet. The preparation process of the positive electrode sheet and the negative electrode sheet is as described above.

[0105] (2) Cutting the tabs

[0106] Design as Figure 5 The winding core 110 shown has three groups of first pole lug areas 113 formed at the first end of the winding core 110, and each group of first pole lug areas 113 has 180 positive pole lugs 1112 arranged along the radial direction of the winding core 110; three groups of second pole lug areas are formed at the second end of the winding core 110, and each group of second pole lug areas has 180 negative pole lugs 1122 arranged along the radial direction of the winding core 110.

[0107] The winding angles from the first positive electrode tab 1112 to the fourth positive electrode tab 1112 are 120°, 240°, 360°, and so on, and the winding angles of two adjacent positive electrode tabs 1112 differ by 120°. Similarly, the winding angles from the first negative electrode tab 1122 to the fourth negative electrode tab 1122 are 120°, 240°, 360°, and so on, and the winding angles of two adjacent negative electrode tabs 1122 differ by 120°.

[0108] On the positive electrode sheet 111, the distance ΔL1 between any two adjacent tabs x and x+1 on the electrode sheet satisfies:

[0109]

[0110] On the negative electrode sheet 112, the distance ΔL2 between any two adjacent tabs y and y+1 on the sheet satisfies:

[0111]

[0112] d ascs It is the sum of the thickness of the positive electrode sheet 111, the negative electrode sheet 112 and the two layers of separators, and its value is 36 μm.

[0113] According to the calculated distance between two adjacent pole tabs, 180 positive pole tabs 1112 and 180 negative pole tabs 1122 are cut out in sequence.

[0114] (3) The positive electrode sheet 111, the separator, the negative electrode sheet 112, and the separator are stacked and wound to form a winding core, and the tabs of the positive electrode sheet 111 and the tabs of the negative electrode sheet 112 are respectively located at the two ends of the winding core.

[0115] (4) Bend the tabs on the positive electrode sheet 111 and the negative electrode sheet 112 toward the center of the winding core.

[0116] (5) The first current collecting plate 120 and the tab on the positive electrode plate 111 , and the second current collecting plate 130 and the tab on the negative electrode plate 112 are welded to form electrical connections.

[0117] (6) The winding core with the first current collecting disc 120 and the second current collecting disc 130 welded is installed in the shell, the first current collecting disc 120 is electrically connected to the pole on the cover plate, and the second current collecting disc 130 is electrically connected to another shell by welding. The cover plate and the pole on the cover plate are insulated, and the cover plate and the shell can be electrically connected by peripheral welding to achieve electrical connection between the cover plate and the shell.

[0118] (7) The shell and the cover are welded to form a battery.

[0119] Example 2

[0120] The only difference from Example 1 is that in step (2), the first pole lug regions and the second pole lug regions are cut into 6 groups, and the winding angles between each two adjacent pole lugs in the first or second pole lug regions differ by 60°.

[0121] Comparative Example 1

[0122] This comparative example provides a traditional full-electrode-ear technology for preparing cylindrical batteries, and the specific steps are as follows:

[0123] The difference from Example 1 is that in step (2), the tabs are not cut; and in step (4), the positive and negative electrode foils are flattened to form a full-tab cylindrical battery.

[0124] Comparative Example 2

[0125] This comparative example provides a traditional multi-electrode technology for preparing cylindrical batteries, and the specific steps are as follows:

[0126] (1) The electrode homogenization process and material ratio are the same as those in Example 1, but during coating, a foil area with a width of 15 mm is set at both ends and in the middle of the positive and negative electrode sheets, respectively, and no active material is coated. No foil area is reserved on the side of the electrode sheet.

[0127] (2) Weld an aluminum tab with a width of 10 mm in the area of ​​the positive electrode sheet that is not coated with active material, and the length of the tab exceeds the width edge of the sheet by 30 mm. Weld a copper tab with a width of 10 mm in the area of ​​the negative electrode sheet that is not coated with active material, and the length of the tab exceeds the width edge of the sheet by 30 mm.

[0128] (3) Same as step (3) in Example 1.

[0129] (4) Weld three positive electrode tabs to the positive current collector and three negative electrode tabs to the negative current collector. The positive current collector is electrically connected to the pole on the cover, and the negative current collector is electrically connected to the shell. Finally, the cover is welded to the shell to form a battery.

[0130] Test Example 1

[0131] The performance of the cylindrical batteries prepared in the test examples and comparative examples is shown in Table 1.

[0132] Test method: (1) Rate discharge performance and temperature rise: In a 25°C environment, ① charge at a constant current of 0.33C to 3.65V, then switch to constant voltage charging with a cut-off current of 0.05C; ② let stand for 15 minutes; ③ then discharge at a constant current of 2C to 2.5V; ④ let stand for 30 minutes. Repeat ① to ②, discharge at a constant current of 3C to 2.5V, and let stand for 30 minutes. Repeat ① to ②, discharge at a constant current of 4C to 2.5V, and let stand for 30 minutes. Record the capacity and temperature rise at different discharge rates.

[0133] (2) 25℃ Cycling Performance: In a 25℃ environment, ① charge at 0.5C constant current to 3.65V, then switch to constant voltage charging with a cut-off current of 0.05C; ② let stand for 15min; ③ discharge at 0.5C constant current to 2.5V; ④ let stand for 15min. Repeat ① to ④ until the discharge capacity reaches 80% of the first discharge capacity, and record the number of cycles.

[0134] Table 1 Performance test results of cylindrical batteries prepared in Examples and Comparative Examples

[0135]

[0136]

[0137] It can be seen from the above data that the multi-pole lug cylindrical battery proposed in the present invention has obvious advantages in reducing internal resistance and eliminating polarization compared with traditional multi-pole lug cylindrical batteries. The discharge capacity at high rate is significantly higher than that of traditional multi-pole lug cylindrical batteries, and the temperature rise during discharge is significantly lower than that of traditional multi-pole lug cylindrical batteries, which can reach the same level as full-pole lug cylindrical batteries.

[0138] Comparative Example 1 is a full-electrode battery. The rate performance (i.e., 2, 3, and 4C discharge capacity) of Comparative Example 1 is relatively good, and the temperature rise is relatively low, but the electrolyte infiltration and reflux effect is not good, and the number of cycles is relatively small. The multi-electrode battery proposed in the embodiment of the present invention can achieve (or approach) the rate performance and temperature rise of the full-electrode battery, and the number of cycles is also significantly improved. Compared with ordinary multi-electrodes, the multi-electrode proposed in the present invention has obvious improvements in rate performance, temperature rise, and number of cycles.

[0139] Compared with the full-electrode-ear cylindrical battery, the multi-electrode-ear cylindrical battery proposed by the present invention can increase the number of cycles by more than 45% when achieving the same life capacity. This is because the number of pole ears and the stacking form of the multi-electrode cylindrical battery will not hinder the infiltration of the electrolyte, which is conducive to the reflux of the electrolyte during the cycle compared to the full-electrode-ear battery, significantly improving the cycle performance.

[0140] In addition, the number of groups is preferably 3 to 8. Generally speaking, the larger the number of groups, the more favorable it is to reduce the internal resistance and improve the rate performance and cycle performance.

[0141] It can be seen from Table 1 that the preparation method provided by the embodiment of the present invention is beneficial to improving the electrochemical performance of the battery compared with the traditional full-electrode tab or multi-stage tab technology.

[0142] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cylindrical battery, characterized in that: The winding core includes a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet includes a positive electrode active material region and a plurality of positive electrode tabs connected to one side of the positive electrode active material region and arranged at intervals, and the negative electrode sheet includes a negative electrode active material region and a plurality of negative electrode tabs connected to one side of the negative electrode active material region and arranged at intervals; The winding core has a first end and a second end opposite to the first end, the plurality of positive electrode tabs are all located at the first end of the winding core, and the plurality of negative electrode tabs are all located at the second end of the winding core; A group of first tab regions is provided at the first end of the winding core, and each group of the first tab regions has a plurality of positive tabs arranged along the radial direction of the winding core; A group b of second electrode tab regions are provided at the second end of the winding core, and each group of the second electrode tab regions has a plurality of the negative electrode tabs arranged along the radial direction of the winding core.

2. The cylindrical battery according to claim 1, characterized in that: a and b satisfy: 1≤a≤20, 1≤b≤20; Preferably, 3≤a≤8, 3≤b≤8.

3. The cylindrical battery according to claim 1 or 2, characterized in that: The winding core is formed by winding a positive electrode sheet, a negative electrode sheet and two layers of separators, and the total number of the positive electrode tabs is m; Definition: The winding angle of the first positive electrode tab on the positive electrode sheet is θ m(1) The winding angle of the a+1th positive electrode tab on the positive electrode sheet is θ m(a+1) , the winding angle of the mth positive electrode tab on the positive electrode sheet is θ m(m) ; The winding angles of the first positive electrode tab and the a+1th positive electrode tab satisfy: θ m(a+1) -θ m(1) =360°; On the positive electrode plate, the distance ΔL1 between any two adjacent tabs x and x+1 on the plate satisfies: Where, d ascs It is the sum of the thickness of the positive electrode sheet, the negative electrode sheet and the two layers of separator.

4. The cylindrical battery according to claim 1 or 2, characterized in that: The winding core is formed by winding a positive electrode sheet, a negative electrode sheet and two layers of separators, and the total number of the negative electrode tabs is n; Definition: The winding angle of the first negative electrode tab on the negative electrode sheet is θ n(1) The winding angle of the b+1th negative electrode tab on the negative electrode sheet is θ n(b+1) The winding angle of the nth negative electrode tab on the negative electrode sheet is θ n(n) ; The winding angles of the first negative electrode tab and the b+1th negative electrode tab satisfy: θ n(b+1) -θ n(1) =360°; On the negative electrode plate, the distance ΔL2 between any two adjacent tabs y and y+1 on the plate satisfies: Where, d ascs It is the sum of the thickness of the positive electrode sheet, the negative electrode sheet and the two layers of separator.

5. The cylindrical battery according to claim 1, characterized in that: The plurality of positive electrode tabs and the plurality of negative electrode tabs are all bent; Preferably, the plurality of positive electrode tabs and the plurality of negative electrode tabs are all bent toward the center direction of the winding core.

6. The cylindrical battery according to claim 1, characterized in that: It also includes a first current collecting plate and a second current collecting plate, the positive electrode tab is electrically connected to the first current collecting plate, and the negative electrode tab is electrically connected to the second current collecting plate.

7. The cylindrical battery according to claim 6, characterized in that: The first current collecting plate has a first connecting protrusions, and each of the first connecting protrusions corresponds to a first pole lug area; The second current collecting plate has b second connecting protrusions, and each of the second connecting protrusions corresponds to a second pole lug area.

8. The cylindrical battery according to claim 6, characterized in that: It also includes a shell and a cover plate, the winding core, the first current collecting disc and the second current collecting disc are all installed in the shell, the first current collecting disc is electrically connected to the pole on the cover plate, and the second current collecting disc is electrically connected to the shell or the pole.

9. A method for preparing a cylindrical battery according to any one of claims 1 to 8, characterized in that: include: Providing a positive electrode sheet having a plurality of positive electrode tabs and a negative electrode sheet having a plurality of negative electrode tabs; After winding, the winding core is formed. By adjusting the spacing between two adjacent positive electrode tabs and the spacing between two adjacent negative electrode tabs, a group of first tab areas a is formed at the first end of the winding core, and each group of the first tab areas has a plurality of positive electrode tabs arranged along the radial direction of the winding core; and a group of second tab areas b is formed at the second end of the winding core, and each group of the second tab areas has a plurality of negative electrode tabs arranged along the radial direction of the winding core; Preferably, the winding angle of the first positive electrode tab on the positive electrode sheet is θ m(1) The winding angle of the a+1th positive electrode tab on the positive electrode sheet is θ m(a+1) , the winding angle of the mth positive electrode tab on the positive electrode sheet is θ m(m) ; The winding angles of the first positive electrode tab and the a+1th positive electrode tab satisfy: θ m(a+1) -θ m(1) =360°; The winding angle of the first negative electrode tab on the negative electrode sheet is θ n(1) The winding angle of the b+1th negative electrode tab on the negative electrode sheet is θ n(b+1) The winding angle of the nth negative electrode tab on the negative electrode sheet is θ n(n) ; The winding angles of the first negative electrode tab and the b+1th negative electrode tab satisfy: θ n(b+1) -θ n(1) =360°; On the positive electrode plate, the distance ΔL1 between any two adjacent tabs x and x+1 on the plate satisfies: On the negative electrode plate, the distance ΔL2 between any two adjacent tabs y and y+1 on the plate satisfies: Where, d ascs It is the sum of the thickness of the positive electrode sheet, the negative electrode sheet and the two layers of separator.

10. An electrical device, characterized in that: It comprises the cylindrical battery according to any one of claims 1 to 8 or the cylindrical battery prepared by the preparation method according to claim 9.

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