Roll core, full-tab cylindrical battery and power utilization device

Abstract

The invention belongs to the technical field of battery processing, and discloses a roll core, a full-tab cylindrical battery and an electric device. The roll core is formed by winding a positive plate, a diaphragm, a negative plate and a diaphragm which are sequentially overlapped, a positive electrode foil of the positive plate is provided with a positive electrode coating layer and a blank foil positioned at the axial end part of the roll core, and a negative electrode foil of the negative plate is provided with a negative electrode coating layer and a blank foil positioned at the axial end part of the roll core; either or both of the blank foil of the positive electrode and the blank foil of the negative electrode have a flat surface formed by bending and overlapping toward the central axis of the winding core, grooves are formed in the flat surface, the number of the grooves in the flat surface is M, blank foil bending regions are formed on the outermost side of one or both of the blank foil of the positive electrode foil and the blank foil of the negative electrode foil, and the blank foil bending regions are formed on the outermost side of one or both of the blank foil of the positive electrode foil and the blank foil of the negative electrode foil. And the bending width of the bending area is W, the theoretical depth D0 of the groove is equal to pi W / M, and the real depth D of the groove is configured to be more than or equal to 0.9 D0 and less than or equal to 1.1 D0, so that wrinkles on the flat surface of the roll core are obviously reduced, and the welding quality of the flat surface and the collector piece is improved.

Description

[0001] This application is a divisional application of the patent application with the application number 202510207431.3 (the application date of the original application is February 25, 2025, and the invention title is core, all - tab cylindrical battery and electrical device). Technical Field

[0002] The present invention relates to the technical field of battery processing, and particularly relates to a core, an all - tab cylindrical battery and an electrical device. Background Art

[0003] The all - tab cylindrical battery has greatly improved the over - current capacity of the battery, reduced the heat generation of the battery, and broken through the bottleneck of the cylindrical battery, thus attracting much attention. Flattening is a key process in the manufacturing of cylindrical all - tab batteries. In order to facilitate the subsequent welding of the current collector on the end of the battery and ensure the welding quality, it is necessary to flatten the end of the battery, flatten the upright tabs of the cylindrical core into a plane, and make the layers of tabs in close contact. At present, the relatively mature processes in the market are rubbing and cutting and stacking. Rubbing is highly destructive to the tabs, and it is extremely easy to generate metal debris, which can easily cause self - discharge and internal short - circuit inside the battery. The cutting and stacking process has low efficiency and high process requirements, and it is also easy to generate metal debris during the tab - cutting process.

[0004] Relatively speaking, pressing is less destructive to the tabs, not easy to generate metal debris, and has better safety performance. However, the technical difficulty is high and the yield rate is low. The pressing technology has just started, and a large number of technical problems need to be overcome. One of the technical problems of pressing is that: since the flat surface of the core is formed by pressing multiple layers of electrode sheets, the extending direction of the outer - layer electrode sheets is consistent with the axial direction of the core before pressing. After pressing, the tops of the multiple layers of electrode sheets are pressed into the flat surface of the core. However, on the flat surface of the core, the stacking of multiple layers of electrode sheets causes obvious wrinkles or plane collapse to form on the pressed flat surface, and the flatness is very poor, which is not conducive to the welding of the flat surface and the current collector.

[0005] Therefore, it is urgent to design a core, an all - tab cylindrical battery and an electrical device to solve the above problems. Summary of the Invention

[0006] An object of the present invention is to provide a core, in which the wrinkles on the flat surface of the core are significantly reduced, the flatness is improved, and the welding quality between the flat surface and the current collector is enhanced.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] A core, which is wound by a positive electrode sheet, a separator, a negative electrode sheet and a separator stacked in sequence. The positive electrode foil of the positive electrode sheet has a positive electrode coating layer and a blank foil at the axial end of the core. The negative electrode foil of the negative electrode sheet has a negative electrode coating layer and a blank foil at the axial end of the core. The blank foils of the positive electrode sheet and the negative electrode sheet face in opposite directions;

[0009] Either one or both of the blank foils of the above-mentioned positive electrode sheet and the blank foils of the above-mentioned negative electrode sheet have a flat surface formed by bending and overlapping toward the central axis of the core, and a groove is formed on the flat surface, and the grooves are radially spaced along the inner circumference to the outer circumference of the core on the flat surface;

[0010] The number of the grooves on the flat surface is M, which is formed on the outermost side of one or both of the blank foils of the positive electrode foil and the negative electrode foil. The bending width of the bending area is W, and the theoretical depth D0 of the groove is D0 = πW / M. The actual depth D of the groove is configured such that 0.9D0 ≤ D ≤ 1.1D0.

[0011] As an alternative, the actual depth D of the groove is configured such that D = D0.

[0012] As an alternative, 4 ≤ M ≤ 12. Preferably, M = 6 or 8.

[0013] As an alternative, the total thickness of the above-mentioned positive electrode sheet, the above-mentioned negative electrode sheet, and two layers of the above-mentioned separator is set as Gap, Gap = T1 + T2 + 2*T3, n*Gap ≤ W < (n + 1)*Gap, T1 is the thickness of the above-mentioned positive electrode sheet, T2 is the thickness of the above-mentioned negative electrode sheet, T3 is the thickness of the above-mentioned separator, n is the stacking number of designed foils, and 4 ≤ n ≤ 16.

[0014] As an alternative, 6 ≤ n ≤ 13.

[0015] The blank foil of the above-mentioned positive electrode sheet can be divided into a vertical area with a length of L along the vertical direction of the core and the bending area, and the physical stiffness of the vertical area is greater than that of the bending area.

[0016] The vertical area is selectively coated with ceramic slurry or insulating glue material to increase the physical stiffness.

[0017] As an alternative, the diameter of the central hole of the above-mentioned core is R1, the outer diameter of the above-mentioned core is R4, a welding area is formed on the flat surface, the welding area is used for welding with the corresponding current collector, the welding area is fan-shaped and concentrically arranged with the core, the outer diameter of the welding area is R3, the inner diameter of the welding area is R2, R3 = R4 - W, and R2 = R1 + W.

[0018] Another object of the present invention is to provide a full-tab cylindrical battery, in which the flatness of the flat surface of the core is higher, the welding quality between the core and the current collector is higher, so that the reliability of the battery is improved.

[0019] To achieve this purpose, the present invention adopts the following technical solutions:

[0020] The all - tab cylindrical battery includes the above - mentioned core and two current collectors. The two current collectors and the two flat surfaces are arranged in one - to - one correspondence and are welded and connected on the above - mentioned welding area.

[0021] Another object of the present invention is to provide an electrical device. By adopting the above - mentioned all - tab cylindrical battery, the electrical reliability of the electrical device is high, and the safety risk of users is reduced.

[0022] To achieve this purpose, the present invention adopts the following technical solutions:

[0023] The electrical device includes the above - mentioned all - tab cylindrical battery and an electrical component. The above - mentioned all - tab cylindrical battery is used to supply power to the above - mentioned electrical component.

[0024] The beneficial effect of the present invention lies in:

[0025] The present invention provides a core. By accurately calculating the depth of the groove, the flat surface absorbs the surplus material that is prone to causing wrinkles due to pressing, thereby reducing the wrinkles in the remaining part of the flat surface except the groove position, ensuring the flatness of the flat surface, and improving the welding stability between the flat surface and the current collector.

[0026] The present invention also provides an all - tab cylindrical battery. By adopting the above - mentioned core, the wrinkles on the flat surface of the core are significantly reduced, the flatness of the core is higher, the welding quality of the current collector is higher, and the reliability of the battery is improved.

[0027] The present invention also provides an electrical device. By using the above - mentioned all - tab cylindrical battery to supply power to the electrical component, the electrical stability of the electrical component is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly and understandably illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The following - described drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0029] Figure 1 is an exploded view of the welding of the core and two current collectors provided by the embodiment of the present invention;

[0030] Figure 2 is a cross - sectional view of the core before pre - pressing provided by the embodiment of the present invention;

[0031] Figure 3 is a cross - sectional view of the core after pressing provided by the embodiment of the present invention;

[0032] Figure 4 is a layered diagram of the interior of the core provided by the embodiment of the present invention;

[0033] Figure 5 It is a schematic diagram of the unfolding of the positive electrode sheet and the negative electrode sheet provided by the embodiment of the present invention;

[0034] Figure 6 It is a schematic diagram of the partition of the flat surface of the core provided by the embodiment of the present invention;

[0035] Figure 7 It is a cross-sectional view of the pressed core cut at the position of the groove provided by the embodiment of the present invention;

[0036] Figure 8 It is a schematic diagram of the bent area of the flat surface of the core provided by the embodiment of the present invention;

[0037] Figure 9 It is a working principle diagram of the electric screwdriver provided by the embodiment of the present invention;

[0038] Figure 10 It is a working principle diagram of the electric vehicle provided by the embodiment of the present invention.

[0039] In the figure:

[0040] 10. Core;

[0041] 11. Flat surface; 111. Welding area; 1111. Welding wire; 112. Groove;

[0042] 13. Positive electrode sheet; 131. Positive electrode active material layer; 132. First blank foil; 14. Negative electrode sheet; 15. Separator;

[0043] 16. Positive electrode flat surface; 17. Negative electrode flat surface; 18. Through hole;

[0044] 20. Current collector;

[0045] 430. Battery pack; 431. Electric screwdriver; 432. Trigger switch; 433. Motor; 434. Shaft; 435. Motor control unit;

[0046] 600. Hybrid vehicle; 601. Engine; 602. Generator; 603. Power drive conversion device; 6041. First drive wheel; 6042. Second drive wheel; 6051. First wheel; 6052. Second wheel; 608. Battery; 609. Vehicle control device; 610. Various sensors; 611. Charging port. Detailed implementation manners

[0047] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, rather than all structures.

[0048] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath", and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0050] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "left", and "right" are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for differentiation in description and have no special meaning.

[0051] Such as Figure 1 is the structure of the all - tab cylindrical battery of an embodiment of the present invention (only the wound core 10 and two current collectors 20 are shown). At the same time, referring to Figure 2 , the wound core 10 is wound by a positive electrode sheet 13, a separator 15, a negative electrode sheet 14, and a separator 15 stacked in sequence, and is in a cylindrical shape as a whole. As Figure 2 shown, in an optional embodiment, the positive electrode active material layer 131 covers most of the positive electrode foil, and the negative electrode active material layer covers most of the negative electrode foil. When in the unfolded state, at both ends of the positive electrode sheet 13 and the negative electrode sheet 14 in the width direction (that is, the positions where the active material is not coated), the aforementioned blank foils are formed. As Figure 2 shown, taking the positive electrode sheet 13 as an example, a first blank foil 132 is formed at the position on the positive electrode foil where the positive electrode active material layer 131 is not coated. Of course, referring to Figure 4 the part of the negative electrode foil where the negative electrode active material is not coated forms a second blank foil (not labeled, Figure 4is located at one end of the core 10 away from the first blank foil 132). As Figure 2 As shown, when the core 10 is wound, in the axial direction, the positive active material layer 131 and the negative active material layer (not shown in the figure) are staggeredly arranged so that the blank foils of the positive electrode sheet 13 and the negative electrode sheet 14 face in opposite directions and are wound into the core 10, and the upper and lower end faces (the lower end face is not shown) are pressed into flat surfaces 11 by a flattening device.

[0052] As Figure 1 and Figure 4 shown, the core 10 is accommodated in a battery case (not shown) in a state where the electrolyte is infiltrated. The positive electrode foil can be a metal foil made of aluminum or an aluminum alloy, and the material of the negative electrode foil can be a metal foil made of copper or a copper alloy.

[0053] As Figure 2 shown, in an alternative embodiment, there is a through hole 18 in the central axis of the core 10, and a positioning pin (not shown in the figure) is inserted into the through hole 18 for welding the current collector 20 and the bottom of the battery case. As Figure 3 and Figure 4 shown, the positive electrode blank foil and the negative electrode blank foil are bent into flat surfaces 11, and the bending direction is from the outer circumference of the core 10 towards the through hole 18, and the adjacent blank foils of the positive electrode sheet 13 or the negative electrode sheet 14 are bent overlapping each other. In the industry, it is generally required that when observing along the axial direction of the core 10, the blank foils on the flat surface 11 should overlap each other by at least 4 layers or more to meet the welding strength between the flat surface 11 and the current collector 20. If the overlap exceeds 16 layers, it will cause serious accumulation of inner peripheral tabs, resulting in the need to accommodate more foil materials in the inner ring multiple bending area, increasing the extrusion degree of the bottom material area, posing a risk of material dropping, and at the same time posing a risk of inner insertion of the tabs causing internal short circuit in the battery, resulting in serious accidents. As Figure 1 and Figure 3 shown, in an alternative embodiment, the current collector 20 is divided into a positive electrode current collector and a negative electrode current collector. The positive electrode current collector is welded to the flat surface 11 formed by the positive electrode blank foil. The positive electrode current collector can be a metal plate or metal sheet made of a single body or composite material of aluminum or an aluminum alloy. The negative electrode current collector is welded to the flat surface 11 formed by the negative electrode blank foil. The negative electrode current collector can be a metal plate or metal sheet made of a single body or composite material of nickel, a nickel alloy, copper, or a copper alloy. A hole is formed near the center of the positive electrode current collector 20, and the position of the hole is the position corresponding to the through hole 18. The negative electrode current collector can be an entire circular current collector or a circular current collector with a circular convex portion in the center. The center position of the current collector 20 at the negative electrode end is further welded to the bottom of the battery case through an externally inserted positioning pin.

[0054] It can be understood that in the present invention Figures 1 to 4They are only schematic diagrams. For example, the actual number of layers of the winding core 10 shall be subject to the embodiments. In an alternative embodiment, the positive electrode active material layer 131 includes any one or more than two kinds of positive electrode materials capable of intercalating and deintercalating lithium. The positive electrode active material layer 131 may further include any one or more than two kinds of other materials such as a positive electrode binder and a positive electrode conductive agent. The positive electrode material may be lithium iron phosphate, or ternary materials such as nickel cobalt manganese series and nickel cobalt aluminum series, as well as other positive electrode materials for lithium ion batteries existing in the prior art.

[0055] In an alternative embodiment, the negative electrode material may be a carbon material, such as artificial graphite and natural graphite, or a graphite-based composite negative electrode material doped with a certain amount of silicon oxide or silicon carbide, as well as other negative electrode materials for lithium ion batteries existing in the prior art.

[0056] In an alternative embodiment, the separator 15 may adopt diaphragms such as single-layer PP, single-layer PE, double-layer PP / PE, double-layer PP / PP, and triple-layer PP / PE / PP; the separator 15 may also be a porous membrane coated with ceramic particles, and the ceramic is preferably Al2O3 or boehmite; the separator 15 may also be other separator materials for lithium ion batteries existing in the prior art.

[0057] In an alternative embodiment, the electrolyte includes a solvent and an electrolyte salt. In addition, the electrolyte may further include any one or more than two kinds of other materials such as additives.

[0058] In an alternative embodiment, the aforementioned solvent includes any one or more than two kinds of non-aqueous solvents such as organic solvents. Among them, the electrolyte with a non-aqueous solvent is a so-called non-aqueous electrolyte, and the non-aqueous solvent may be, for example, a cyclic carbonate, a chain carbonate, a lactone, a chain carboxylate, a nitrile (mononitrile), etc.

[0059] In an alternative embodiment, the aforementioned electrolyte salt may include, for example, any one or more than two kinds of salts such as lithium salts. In addition, the electrolyte salt may also include salts other than lithium salts. The salts other than lithium salts may be, for example, light metal salts other than lithium.

[0060] In one embodiment, the battery housing is a metal shell, and the metal shell may be a steel shell or an aluminum shell, and is further preferably a steel shell. In one embodiment, the model of the battery is preferably a 18650-type or 21700-type cylindrical battery, but the present invention is not limited to the above two kinds of cylindrical batteries.

[0061] In an optional embodiment, the aforementioned lithium salt is, for example, lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium tetraphenylborate (LiB(C6H5)4), lithium methanesulfonate (LiCH3SO3), lithium trifluoromethanesulfonate (LiCF3SO3), lithium tetrachloroaluminate (LiAlCl4), lithium disilicate hexafluoride (Li2SF6), lithium chloride (LiCl), lithium bromide (LiBr), and the like. Among them, the aforementioned lithium salt can be any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate; the aforementioned lithium salt is more preferably lithium hexafluorophosphate. The content of the electrolyte salt is not particularly limited. Among them, it is preferably 0.3 mol / kg to 3 mol / kg relative to the solvent.

[0062] The blank foil on the flat surface 11 and the blank foil in the groove are continuous and not cut by a cutting device or the like. The groove is obtained by pressing down the clamping claws of the flattening device.

[0063] In the prior art, due to the inward bending of the positive electrode blank foil or the negative electrode blank foil, the circumferential dimension of the blank foil before and after bending is reduced, which easily causes wrinkles on the flat surface 11 and is not conducive to the welding of the flat surface 11 and the corresponding current collector 20.

[0064] To solve the above problems, as Figures 3 - 6 shown, this embodiment provides a core 10. The wrinkles on the flat surface 11 of the core 10 are significantly reduced, the flatness of the flat surface 11 is significantly improved, and the welding quality of the flat surface 11 and the current collector 20 is improved. As Figure 4 and Figure 6 shown, the flat surface 11 is formed with grooves 112. The grooves 112 are radially spaced along the inner circumference to the outer circumference of the core 10 on the flat surface 11; the number of grooves 112 on the flat surface 11 is M. A bending area is formed on the outermost side of one or both of the blank foil on the positive electrode foil and the blank foil on the negative electrode foil. The bending width of the bending area is W. The theoretical depth D0 of the groove 112 = πW / M, and the actual depth D of the groove 112 is configured such that 0.9D0 ≤ D ≤ 1.1D0.

[0065] It should be noted that the groove 112 and the flat surface 11 are formed on a flattening device.

[0066] As an embodiment, typically, the flattening method of the flattening device can be a two-step flattening method:

[0067] 1. Pre-press - form the groove 112. First, pre-press the unbent blank foil on the unflattened core 10 to form the expected groove 112;

[0068] 2. Flattening - forming a flat surface 11 and the final groove 112, flatten the pre - pressed battery cell to obtain the Figure 1 flattened wound core 10 in

[0069] It can be understood that in the present invention, the groove structure mentioned refers to the groove 112 of the finally flattened wound core 10, and the groove structure includes the depth and width of the groove 112, etc. Since the groove 112 formed during the pre - pressing process and the groove 112 structure of the finally flattened wound core 10 may be slightly different, therefore, the groove 112 in the present invention is based on the groove 112 of the finally flattened wound core 10. The flattened wound core 10 is also the final product of the flattening step, and its subsequent step is to be welded to the positive current collector and the negative current collector. It can be understood that referring to Figure 2 and Figure 4 , taking the positive flat surface 16 of the wound core 10 as an example, before pressing, the blank foil of the positive electrode foil extends along the axial direction of the wound core 10, and the top of the blank foil of the positive electrode foil (i.e., the first blank foil 132) is flattened (part of the first blank foil 132) by the pressing tooling to form the positive flat surface 16. The flattened part is the bending part, and the length of the bending part bent inward is W.

[0070] Among them, as Figure 4 shown, the blank foils of the positive electrode sheet 13 (i.e., the first blank foil) and the negative electrode sheet 14, due to the different flattening structures, are discussed separately for the positive and negative electrodes. The blank foil of the positive electrode sheet 13 can be divided into the form of L + W, where L is the vertical area and W is the bending area. Due to the design of the electrode sheet structure, the negative electrode sheet 14 is wider than the positive electrode sheet 13 in the width direction, and the entire negative electrode sheet 14 covers the positive electrode sheet 13. Therefore, in the width direction of the electrode sheet (i.e., the length direction of the wound core 10), the vertical area can be further divided into an outer vertical area L1 and an inner vertical area L2, L = L1 + L2, and the entire blank foil of the positive electrode is L + W. Generally speaking, since the physical stiffness requirements of L1 and L2 are much greater than those of the W part, therefore, in the actual design of the wound core, ceramic slurry or insulating glue and other substances will be coated on L2 to increase the stiffness of L2 to resist bending. At the same time, its insulating coating can effectively relieve the internal short - circuit between the positive electrode sheet 13 and the negative electrode sheet 14. For the L1 part, according to needs, we will also coat ceramic slurry or insulating glue and other substances on most or all of the area of L1 to increase the stiffness of L1 to resist bending. The coatings on L1 and L2 are continuous coatings, and the two materials can be the same and are coated simultaneously. It can be understood that the vertical area has stronger physical stiffness than the bending area, ensuring that the vertical area remains generally vertical during the flattening process and preventing excessive interference with the negative electrode sheet 14.

[0071] At the same time, as Figure 4 and Figure 6As shown, the outer vertical region L2 is arranged in such a way that the projection of the positive electrode active material layer 131 can completely fall within the negative electrode active material layer, avoiding the edge of the negative electrode sheet 14 piercing the separator 15 and contacting the positive electrode active material layer 131 to cause a short circuit.

[0072] Through the long-term practical exploration by technicians, when L1 / L2 < 0.2, this ratio is too small to effectively protect the negative electrode sheet 14, and at the same time, it affects the winding alignment accuracy (this part mainly considers the method of applying glue). When L1 / L2 > 2, this ratio is too large, the battery energy density will be affected, and the battery capacity will be reduced by about 2.5% - 5%. In an optional embodiment, 0.2 ≤ L1 / L2 ≤ 2 is adopted. Through this setting method, the effect of protecting the negative electrode sheet 14 can be achieved simultaneously, ensuring the winding alignment accuracy, and the energy density of the battery will not be affected.

[0073] For the negative electrode, its structure is basically the same as that of the positive electrode. The main difference is that on the positive electrode side, there is a situation where the negative electrode sheet 14 is wider than the positive electrode sheet 13 in the width direction. On the negative electrode side, the above structure does not exist, and the entire negative electrode protrudes from the positive electrode sheet 13. Of course, the blank foil on the negative electrode side can also be divided into the form of a vertical region and a bent region L + W (not shown in the figure), but L does not need to be further divided into L1 and L2. For the L part on the negative electrode side, we can also choose to coat ceramic slurry or insulating glue and other substances to increase the stiffness of L. However, considering the flattening process, if the vertical region part of the negative electrode itself can meet the requirement of being rigid during flattening, then it is also possible not to coat ceramic slurry or insulating glue and other substances. The core reason is that on the negative electrode side, there is no need to consider the problem of internal short circuit caused by the contact between the negative electrode sheet 14 and the positive electrode. Therefore, the ceramic slurry or insulating glue coating on the negative electrode side is an optional item and can be selected according to actual needs.

[0074] It should be noted that in the actual product, the vertical region and the bent region can be directly connected or can be smoothly transitioned through a transition structure. In the present invention, the directly connected method is adopted.

[0075] In an optional embodiment, as Figure 4 shown, a separator 15 is clamped between adjacent negative electrode sheets 14 of each turn of the positive electrode sheet 13. One end of the wound multi-layer positive electrode sheet 13 is pressed to form a flat surface 11 (positive electrode flat surface 16), and one end of the wound multi-layer negative electrode sheet 14 is pressed to form another flat surface 11 (negative electrode flat surface 17). W = n * Gap, Gap = T1 + T2 + 2 * T3, where T1 is the thickness of the positive electrode sheet 13, T2 is the thickness of the negative electrode sheet 14, and T3 is the thickness of the separator 15. The foil material here generally refers to the blank foil of the positive electrode or the blank foil of the negative electrode. Taking Figure 4 as an example for illustration, Figure 3Among them, the number of stacked layers of the foil of the positive electrode is 4 layers, that is, the outermost positive electrode sheet 13 can be lapped on the fifth positive electrode sheet 13 counted from the outside to the inside after flanging. Ignoring the rounded corners, the length of W should cover the thicknesses of 4 negative electrode sheets 14, 4 positive electrode sheets 13 (each taking half of the positive electrode sheets 13 on both sides), and 8 separator sheets 15, which just meets the requirement that the number of stacked layers of the foil of the positive electrode is 4 layers. A stacked layer number less than 4 layers does not meet the welding conditions. When n is other values, it is necessary to ensure that n*Gap ≤ W < (n + 1)*Gap, where Gap = T1 + T2 + 2*T3. T1, T2, and T3 are all known. n is the designed number of stacked layers of the foil, and the value of W can be determined more conveniently, and then the value of D0 can be determined.

[0076] n*Gap ≤ W < (n + 1)*Gap, where n is the designed number of stacked layers of the foil, and 4 ≤ n ≤ 16. This formula can be understood as follows: after designing the number of stacked layers of the foil, we can adjust the width W of the bending area to meet the design of this stacked layer number. For example, when the number of stacked layers of the foil is 6, at this time 6Gap ≤ W < 7Gap. It can be realized that the uppermost end of the first-layer bending area can reach the root of the seventh-layer bending area (at this time W = 6Gap), or the uppermost end of the first-layer bending area can partially cover the area of the seventh-layer bending area and does not reach the area of the eighth-layer bending area. At this time, looking down from the entire flat surface, it can be found that the number of stacked layers of the foil is 6. When 6Gap ≤ W < 7Gap, we can make the actual stacked layer number of the entire flat surface (taking the welding area as the standard) reach at least 6 layers. In most cases, the actual stacked layer number of the entire flat surface (taking the welding area as the standard) is between 6 and 7 layers (when 6Gap < W < 7Gap). It meets the design requirements and can achieve the technical effects of the present invention.

[0077] In an optional embodiment, at least 4 layers of foils are stacked to ensure sufficient welding depth during subsequent welding with the current collector 20, avoid welding through, and meet the qualified requirements of other welding indicators. Therefore, the lower limit n ≥ 4 is set. Looking along the height direction of the core 10, the number of stacked layers of the blank foils on the flat surface 11 must be greater than or equal to 4 layers. If it is less than 4 layers, it will greatly affect the welding yield, cause welding failure, and most likely cause the laser to weld through the tab and further damage the lower electrode sheet and separator 15, resulting in a more serious internal short circuit in the core 10. At the same time, if the number of stacked layers of the tabs used for welding is too small, its internal resistance will also increase, the welding tensile force is too small and does not meet the standard, and the drum experiment will also fail. All point values or ranges greater than or equal to 4 are within the protection scope of this optional embodiment.

[0078] In an optional embodiment, in the extreme case, when ensuring the stacking of four layers of foils, the technical effects of the present invention can also be basically achieved, and the welding effect at this time can also basically meet the requirements. At this time, n = 4, 4Gap ≤ W < 5Gap, and at this time, it can be ensured that the actual stacking layers of the entire flat surface (taking the welding area as the reference) are four layers and five layers.

[0079] Therefore, n = 4 also belongs to the protection scope of the present invention. The range of 4 ≤ n ≤ 16 in all embodiments of the present invention has considered the upper and lower limits of the foil stacking that can implement the technical solution of the present invention.

[0080] The total thickness of the positive electrode sheet 13, the negative electrode sheet 14, and the two separator membranes 15 is set to Gap, Gap = T1 + T2 + 2*T3, n*Gap ≤ W < (n + 1)*Gap, where T1 is the thickness of the positive electrode sheet 13, T2 is the thickness of the negative electrode sheet 14, T3 is the thickness of the separator membrane 15, n is the number of stacked foil layers designed, and 4 ≤ n ≤ 16.

[0081] At the same time, considering that when the value of n is too large, the foils near the inner circle of the core 10 will have a more serious stacking situation of the electrode sheets close to the center due to the too large W value. This is mainly because the position closest to the center of the edge after flanging of the foils in the inner circle can only abut against the positioning pins of the core 10. The flanging of the foils further inward not only has excess material in the circumferential direction but also has excess material in the radial direction due to the blockage of the positioning pins. After being flattened, it will lead to an increase in the extrusion degree of the foils and damage the negative electrode material area. To avoid the aggravation of the excess material situation of the foils near the positioning pins caused by too large W value, and considering the battery design efficiency and energy density at the same time, it is set that n ≤ 16. Among them, n can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, etc. All point values or ranges greater than or equal to 4 and less than or equal to 16 are within the protection scope of this optional embodiment.

[0082] For safety, in an optional embodiment, n ≤ 13. In addition, when n ≥ 6, most designs of the core 10 can be satisfied. Therefore, when n is in the range of 6 - 13, it is a more preferred solution. And within this range, the battery design efficiency and energy density are more optimized, and the situation of damaging the negative electrode material area is less. Among them, n can be 6, 7, 8, 9, 10, 11, 12, 13, etc. All point values or ranges greater than or equal to 6 and less than or equal to 13 are within the protection scope of this optional embodiment.

[0083] To better illustrate the process of confirming the depth of the groove, taking the positive electrode sheet 13 as an example, from Figure 2 the state to Figure 3 the state, each layer of the positive electrode sheet 13 undergoes a "flanging" operation from before being flattened to after being flattened.

[0084] In an alternative embodiment, as Figure 4 and Figure 7 shown, taking the outermost ear of the positive electrode as an example, the width of the bending area is W. The bending area includes the upper end (outer end) and the root, and the root is connected to the vertical area. At this time, the circumference of the outermost ear around the winding core 10 for one week is 2πR4. When the outermost ear is flattened, it is folded inward, and the position where the uppermost end of the bending area reaches is the position of R4 - W. At this time, the circumference of one circle at the position of R4 - W is 2π(R4 - W). For the uppermost end of the outermost ear, it obviously has an ear allowance of 2πR4 - 2π(R4 - W) = 2πW. If this part of the ear is not processed, simply believing that "not being processed" in the present invention means not performing a grooving design, a large number of wrinkles will be generated on the flattened end face, making the flatness of the flat surface 11 very poor and difficult to weld, and ultimately the purpose of the present invention cannot be achieved. The above-mentioned wrinkles need to be counteracted by the groove 112 to absorb this part of the redundant ear, and finally a smooth and defect-free flat surface 11 is formed on the flattened flat surface 11. That is, by accurately calculating the depth of the groove 112 for the winding core 10, the surplus material that is likely to cause wrinkles due to pressing on the flat surface 11 is absorbed by the groove 112, thereby reducing the wrinkles in the remaining part of the flat surface 11 except for the position of the groove 112, and further ensuring the flatness of the flat surface 11 and improving the welding stability between the flat surface 11 and the current collector 20. The negative electrode sheet 14 is the same as the positive electrode sheet 13 and will not be elaborated here.

[0085] In an alternative embodiment, as Figure 6 shown, for the calculation of the depth of the groove 112, it is assumed that there are M grooves 112, and the cross-section of the groove 112 is preferably rectangular. The groove 112 is generally a through cuboid that is straight from the inner circumference to the outer circumference, and its position on the winding core 10 is equally deep from the inner circumference to the outer circumference. The groove 112 with a rectangular cross-section has a simple structure and is convenient for processing.

[0086] In an alternative embodiment, the width of the groove 112 can be of equal width. However, it can also have other widths, such as a gradually changing width, such as the shape of a flared opening, for example, the groove 112 is wide at the outer circumference and narrow at the inner circumference. The selection of the above width does not affect the realization of the technical effect of the present invention. In fact, as long as the equal depth is ensured, the width can be selected according to the actual situation.

[0087] In an alternative embodiment, as Figure 7 shown, the depth of the groove 112 is set to D. A rectangular groove 112 has two (the two side walls of the rectangular groove 112). Generally speaking, for M grooves 112, the number of side walls is 2M, so it is necessary to ensure that 2M * D = 2πW, that is, D = πW / M, and the most preferred theoretical value can be obtained. Finally, D0 = πW / M is obtained.

[0088] In an alternative embodiment, the present invention further discovers that the actual design can be carried out around the point value of D0 = πW / M. We find that D within the range of 0.9D0 ≤ D ≤ 1.1D0 can also achieve the technical effects of the present invention, which will be discussed in detail later. Among them, D can be 0.9D0, 0.91D0, 0.92D0, 0.93D0, 0.94D0, 0.95D0, 0.96D0, 0.97D0, 0.98D0, 0.96D0, D0, 1.01D0, 1.02D0, 1.03D0, 1.04D0, 1.05D0, 1.06D0, 1.07D0, 1.08D0, 1.09D0, 1.1D0, etc. All point values or ranges greater than or equal to 0.9D0 and less than or equal to 1.1D0 are within the protection scope of this alternative embodiment.

[0089] In an alternative embodiment, as Figure 6 shown, for the number M of the slots 112, generally, a symmetric number or a number that can evenly divide the circumference can be selected. Generally speaking, the number of M should be greater than or equal to 4. M can be selected as different numbers such as 4, 5, 6, 8, 9, 10, 12, etc. All point values or ranges greater than or equal to 4 and less than or equal to 12 are within the protection scope of this alternative embodiment. Among them, starting from the size of the commonly used core 10, the number M of this alternative embodiment can be selected as 6 or 8.

[0090] In an alternative embodiment, as Figure 6 shown, the slots 112 on the flat surface 11 can be evenly arranged in the entire circumferential region, with the same angle between them, so as to ensure the uniformity of the overall strength and hardness of the flat surface 11 and the overall flatness, and ensure the stable welding effect between the flat surface 11 and the current collector 20. Of course, in other alternative embodiments, it is not excluded that some areas may not be provided with slots 112, or the slots 112 can also be arranged in an unequal spacing form. Different arrangement methods of the slots 112 are within the protection scope of this application.

[0091] In an alternative embodiment, as Figure 6As shown, the arrangement of the slots 112 should extend from the inner circumference to the outer circumference of the core 10 and penetrate the entire core 10. This design divides the flat surface 11 into several independent fan-shaped regions, which are used for welding with the current collector plates 20, and these fan-shaped regions are called welding regions 111. These welding regions 111 can be identical fan-shaped regions, and these fan-shaped regions are independent of each other and not connected. For example, in this embodiment, the preferred solution is that the core 10 is divided into eight fan-shaped welding regions 111 of equal area by eight slots 112 that are equally spaced at an angle of 45°. In an alternative embodiment, the authenticity D is configured such that 0.9D0 ≤ D ≤ 1.1D0. When D < 0.9D0, we found through experiments that the test data are shown in Table 1. In Comparative Example 1, D = 0.8D0, the flatness is 0.75 mm, and the welding defect rate is 15.10%. In Comparative Example 2, D = 0.85D0, the flatness is 0.61 mm, and the welding defect rate is 8.23%. In Example 1, D = 0.9D0, the flatness is 0.40 mm, and the welding defect rate is 0.99%. In Example 2, D = 0.95D0, the flatness is 0.32 mm, and the welding defect rate is 0.30%. In Example 3, D = D0, the flatness is 0.2 mm, and the welding defect rate is 0.10%. In Example 4, D = 1.05D0, the flatness is 0.3 mm, and the welding defect rate is 0.22%. In Example 5, D = 1.1D0, the flatness is 0.38 mm, and the welding defect rate is 0.38%. In Comparative Example 3, D = 1.15D0, the flatness is 0.55 mm, and the welding defect rate is 4.97%. In Comparative Example 4, D = 1.2D0, the flatness is 0.70 mm, and the welding defect rate is 10.65%. Among them, the welding defect rate refers to the proportion of the number of finished batteries that cannot be used normally in the test quantity after the core 10 is welded to the two current collector plates 20 to form a finished battery.

[0092] Table 1

[0093] <![CDATA[True depth D0 of the groove]]> Flatness (mm) Welding defect rate Comparative Example 1 <![CDATA[D = 0.8D0]]> 0.75 15.10％ Comparative Example 2 <![CDATA[D = 0.85D0]]> 0.61 8.23％ Example 1 <![CDATA[D = 0.9D0]]> 0.4 0.99％ Example 2 <![CDATA[D = 0.95D0]]> 0.32 0.30％ Example 3 <![CDATA[D = D0]]> 0.2 0.10％ Example 4 <![CDATA[D = 1.05D0]]> 0.3 0.22％ Example 5 <![CDATA[D = 1.1D0]]> 0.38 0.87％ Comparative Example 3 <![CDATA[D = 1.15D0]]> 0.55 4.97％ Comparative Example 4 <![CDATA[D = 1.2D0]]> 0.7 10.65％

[0094] As can be seen from Table 1, when D < 0.9D0, due to insufficient pressing, the pressing amount of the groove for absorbing the excess tabs on the flat surface 11 is insufficient, and the excess tabs pile up on the flat surface 11. From the test results, there are wrinkles on the flat surface 11 after pressing the core 10, and its flatness is also poor, with the flatness range being 0.5 - 0.75 mm, and the welding defect rate is very high, reaching more than 3%; even when the flatness is above 0.61 mm, the welding defect rate reaches more than 8.23%. When D > 1.1D0, it also exceeds the expected threshold, and the amount used to absorb the excess tabs on the flat surface 11 exceeds the limit, resulting in the tabs for forming the flat surface 11 being dragged into the groove 112, causing the situation that the groove 112 grabs the tabs from the flat surface 11. Visually, there are pits at the junction of the flat surface 11 and the groove 112, and the boundary between the groove 112 and the flat surface 11 is blurred. The wrinkles are slightly better than the case of "D < 0.9D0". Although the overall feeling is slightly better than "D < 0.9D0", in terms of the actual effect, it can also be seen that when D > 1.1D0, the flatness of each flat surface 11 is 0.5 mm - 0.7 mm, and the welding defect rate also reaches more than ~3%. The minimum requirement of the present invention is that the flatness of the flat surface 11 is controlled within 0.4 mm. Such flatness is a more ideal welding plane, and the welding defect rate can be generally controlled within 1.0%.

[0095] When we choose 0.9D0 ≤ D ≤ 1.1D0, from the test results, we can see that the entire flat surface 11 is flat without obvious defects, achieving the expected flattening technical effect. Its flatness range is within 0.2 mm - 0.4 mm, and the welding defect rate is within 1.0%, meeting the technical requirements of the present invention. Within this range, the welding task of the present invention can be efficiently achieved.

[0096] When the flatness of the core 10 is above 0.5 mm, the entire flat surface 11 of the core 10 is basically in a state where welding is impossible. If we forcibly attempt to weld the current collector 20 and the flat surface 11, a greater pressing force between the current collector 20 and the core 10, as well as an increase in the laser penetration depth, etc. are required; even so, it will still lead to problems such as the effective welding wire 1111 being too short, forming a false weld, and the tensile strength being too small. All these problems result in the unqualified battery after welding and cannot be normally transferred to the subsequent processes. The present invention collectively refers to these unqualified weldings as the welding defect rate. Further understanding of 0.9D0 ≤ D ≤ 1.1D0, we can consider D = D0 as a preferred choice of the present invention. However, for D within 0.9D0 ≤ D ≤ 1.1D0, the technical effect of the present invention can also be achieved, belonging to the parameter range required by the present invention.

[0097] As a more preferred technical solution, 0.95D0 ≤ D ≤ 1.05D0. At this time, the flatness is better, and it can be within 0.32 mm. The welding defect is further reduced to within 0.30%, and better technical effects can be achieved.

[0098] In summary, when 0.9D0 ≤ D ≤ 1.1D0, the flatness of the core 10 can achieve the technical effects of the present invention, significantly reducing wrinkles, with a higher flatness of the core, and ultimately a higher welding quality of the current collector 20, and the reliability of the battery is also significantly improved.

[0099] Combined with Figure 6 The acquisition of the flatness of the flat surface 11 will be described. As Figure 6 shown, in the test, a 3D profiler was used to measure the flatness of the flat surface 11 of the core 10. The plane to be measured was selected, and the machine identified the highest point and the lowest point in the selected area, and automatically calculated the difference between the high and low points, which is the flatness.

[0100] The calculation formula of the flatness is as follows:

[0101] F = H1 - H2;

[0102] Wherein, F is the flatness of the test area of the flat surface 11 of the core 10, H1 is the height of the highest point in the test area of the flat surface 11 of the core 10, and H2 is the height of the lowest point in the test area of the flat surface 11 of the core 10. Figure 6 The shaded part in is the entire eight-piece plane area to be measured. In a specific embodiment, the flatness measured in the present invention is the flatness of the entire end face of the battery cell (including eight welding areas).

[0103] Exemplarily, Figure 6 the shaded part in is the eight welding areas 111 to be measured. The eight welding areas 111 are used for welding with the corresponding current collectors 20. Those skilled in the art can measure the flatness of the entire flat surface 11 as needed, or measure the flatness of each welding area 111 separately. The data in Table 1 reflects the flatness of the entire flat surface 11.

[0104] In an alternative embodiment, as Figure 7 and Figure 8 shown, the diameter of the central hole of the core 10 is R1, the outer diameter of the core 10 is R4, the flat surface 11 forms a welding area 111, the welding area 111 is used for welding with the corresponding current collector 20, the welding area 111 is annular and concentric with the core 10, the outer diameter of the welding area 111 is R3, the inner diameter of the welding area 111 is R2, and R3 = R4 - W, R2 = R1 + W. In this case, Figure 6 the outer circumference and the inner circumference of the sector of the welding area 111 and Figure 8R3 and R4 in the figure are overlapped. It can be understood that the setting of the welding area 111 ensures the stability of the welding between the flat surface 11 and the current collecting sheet 20. Figure 3 and Figure 4 Taking the outermost positive electrode sheet 13 as an example, the outermost positive electrode sheet 13 is overlapped on the fifth positive electrode sheet 13 inward after being flanged. From the fourth layer inward, a visible multi-layer flanged positive electrode sheet 13 is formed. In this position, due to the setting of the groove 112, the plane area after the pressing is conducive to subsequent welding. At the same time, with the center hole as the boundary, the edge of the positive electrode sheet 13 expanded outward by a distance W just butts against the positioning pin. In the positive electrode sheet 13 with a radius less than R2 and greater than R1, its flanged edge all butts against the positioning pin, and there is a pile of materials in the radial direction. This area is no longer suitable for welding with the current collector 20.

[0105] In another preferred embodiment, since W=n*Gap, 4≤n≤16. When the value of n is small, for example, 4≤n≤8, it is more appropriate to select the outer diameter of the fan-shaped welding area 111 to coincide with R3. At this time, the outer diameter to the inner diameter of the welding area 111 should be from R3=R4-W to R2=R1+W; however, for example, when 8<n≤16, the area covered by W is relatively large, and the stacked tabs have already met the requirement of the lower limit of 4-layer stacking. Therefore, the outer diameter of the fan-shaped welding area 111 can be selected to be a fixed distance, and the inner diameter remains unchanged, for example, 8*Gap is used as the upper limit of the outer diameter of the fan-shaped welding area 111. At this time, the outer diameter to the inner diameter of the welding area 111 should be from R3=R4-8*Gap to R2=R1+W.

[0106] In an alternative embodiment, see Figure 6 , the overall flatness of the welding area 111 is within 0.25mm, and the flatness of each welding area 111 is within 0.2mm, so that when welding with the current collector 20, the current collector 20 has a good fit with the flat surface 11, and each welding area 111 is welded to the corresponding position of the current collector 20 through a welding wire 1111, and the effective welding rate of the welding wire 1111 is close to 100%. At the same time, the welding wire 1111 is a straight spiral welding, which is simple in shape and convenient for welding. It should be noted that since the flat surface obtained by the present invention has a high flatness, the selection of the welding wire 1111 is not limited to the straight spiral welding, and the existing welding wires can be used.

[0107] In an optional embodiment, if Figure 6 As shown, a plurality of welding wires 1111 are evenly distributed radially from the center of the winding core 10. Through the above arrangement, the uniformity of welding between the flat surface 11 and the corresponding current collecting sheet 20 is improved. Figure 6As shown, the number of bonding wires 1111 and grooves 112 is set to eight. In other embodiments, it can be understood that in the present invention, it is not necessary to perform welding on all welding areas 111. The number of bonding wires 1111 can also be less than the number of welding areas 111, and can also be 3, 4, 5, 6, 7, etc., which is not limited herein.

[0108] For a specific embodiment, detailed specific parameters are given:

[0109] The dimensions of the core 10 are R1 = 1.5 mm and R4 = 10.2 mm;

[0110] W = n * Gap, Gap = T1 + T2 + 2 * T3, T1 = 85 μm, T2 = 80 μm, and T3 = 12 μm, 1Gap = 189 μm, n = 11, obtaining a value of W = 1.89 mm.

[0111] For the positive electrode, L1 = 1.8 mm, L2 = 1.3 mm, L positive = 3.1 mm, and W = 1.89 mm. The total height of the first blank foil 132 is L + W = 4.99 mm; for the negative electrode, L negative = 1.4 mm and W = 1.89 mm, and the total height of the blank foil is L + W = 3.29 mm; where the inner diameter R1 = 1.5 mm and the outer diameter is 10.2 mm. Therefore, the weldable area 111 is in the range of R1 + w to R4 - W. So, the weldable area 111, from the inner circumference to the outer circumference of the core 10, has a range of R2 = R1 + w to R3 = R4 - W, with values of R2 = 3.39 mm to R3 = 8.31 mm. The value of M is 8;

[0112] D0 = πW / M = 0.742 mm.

[0113] Our selection range is 0.9D0 ≤ D ≤ 1.1D0. In this embodiment, 0.668 mm ≤ D ≤ 0.816 mm;

[0114] In a preferred embodiment of this, we select D = D0, then D = 0.742 mm.

[0115] In another embodiment, we select D = 1.02D0, then D = 0.757 mm; in another embodiment, we select D = 0.96D0, then D = 0.712 mm.

[0116] For another specific embodiment, detailed specific parameters are given:

[0117] The dimensions of the core 10 are R1 = 1.5 mm and R4 = 10.2 mm;

[0118] W = n * Gap, Gap = T1 + T2 + 2 * T3, T1 = 85 μm, T2 = 80 μm, T3 = 12 μm, 1Gap = 189 μm, n = 8, and finally the measured value of W is 1.323 mm.

[0119] For the positive electrode, L1 = 1.8 mm, L2 = 1.3 mm, L_pos = 3.1 mm, and W = 1.323 mm. The total height of the first blank foil 132 is L_pos + W = 4.423 mm; for the negative electrode, L_neg = 1.4 mm and W = 1.323 mm, and the total height of the blank foil is L_neg + W = 2.723 mm;

[0120] Among them, the inner diameter R1 = 1.5 mm and the outer diameter is 10.2 mm. Therefore, the weldable area 111 is in the range of R2 = R1 + w to R3 = R4 - W. So, the weldable area 111 ranges from the inner circumference to the outer circumference of the core 10, with a value of 2.823 mm - 8.877 mm. The value of M is 6;

[0121] D0 = πW / M = 0.692 mm. Among them, 0.9D0 ≤ D ≤ 1.1D0. In this embodiment, 0.623 mm ≤ D ≤ 0.761 mm.

[0122] In a preferred embodiment of this example, we choose D = D0, then D = 0.692 mm.

[0123] In another embodiment, we choose D = 1.06D0, then D = 0.734 mm; in another embodiment, we choose D = 0.92D0, then D = 0.637 mm.

[0124] This embodiment also provides a full-tab cylindrical battery, including the above-mentioned core 10 and two current collectors 20. The two current collectors 20 are arranged in one-to-one correspondence with the two flat surfaces 11 and are connected by welding. By adopting the above-mentioned core 10, the flatness of the core 10 is higher, the welding quality of the current collector 20 is higher, and the reliability of the battery is improved.

[0125] This embodiment also provides an electrical device, including the above-mentioned full-tab cylindrical battery and an electrical component. The full-tab cylindrical battery is used to supply power to the electrical component. By using the above-mentioned full-tab cylindrical battery to supply power to the electrical component, the power supply stability of the electrical component is improved.

[0126] In an alternative embodiment, the electrical component may be an electronic device. For example, it may include a notebook personal computer, a smart phone, a tablet terminal, a PDA (portable information terminal), a mobile phone, a wearable terminal, a cordless phone handset, a video camera, a digital camera, an e-book, an electronic dictionary, a music player, a radio, a headset, a game console, a navigation system, a memory card, a pacemaker, a hearing aid, a power tool, an electric shaver, a refrigerator, an air conditioner, a television, an audio system, a water heater, a microwave oven, a dishwasher, a washing machine, a dryer, a lighting device, a toy, a medical device, a robot, a load regulator, a signal lamp, etc.

[0127] Refer to Figure 9 , and briefly describe an example of a power tool to which the present invention can be applied, such as an electric screwdriver. In the main body of the electric screwdriver 431, a motor 433 such as a DC motor is housed. The rotation of the motor 433 is transmitted to the shaft 434, and a screw is screwed into the object through the shaft 434. A trigger switch 432 operated by the user is provided on the electric screwdriver 431.

[0128] In the lower frame of the handle of the electric screwdriver 431, a battery pack 430 (the battery pack 430 may be composed of a plurality of full-tab cylindrical batteries) and a motor control unit 435 are housed. As the battery pack 430, the battery pack 430 can be used. The motor control unit 435 controls the motor 433. Each part of the electric screwdriver 431 other than the motor 433 can also be controlled by the motor control unit 435. Although not shown, the battery pack 430 and the electric screwdriver 431 are engaged by engaging members provided on each of them. As described later, the battery pack 430 and the motor control unit 435 each include a microcomputer. Battery power is supplied from the battery pack 430 to the motor control unit 435, and information of the battery pack 430 is communicated between the microcomputers of the two.

[0129] The battery pack 430 is, for example, freely detachable from the electric screwdriver 431. The battery pack 430 may also be built into the electric screwdriver 431. The battery pack 430 is installed on a charging device during charging. It should be noted that when the battery pack 430 is installed on the electric screwdriver 431, a part of the battery pack 430 may be exposed to the outside of the electric screwdriver 431, and the user can visually recognize the exposed part. For example, an LED may be provided on the exposed part of the battery pack 430 so that the user can confirm the lighting and extinguishing of the LED.

[0130] The motor control unit 435 controls the rotation, stop, and rotation direction of the motor 433. Further, the power supply to the load is cut off during over-discharge. The trigger switch 432 is inserted, for example, between the motor 433 and the motor control unit 435. When the user presses the trigger switch 432, the motor 433 is powered and the motor 433 rotates. When the user returns the trigger switch 432, the rotation of the motor 433 stops.

[0131] In an alternative embodiment, the electrical component may be an electric vehicle. As electric vehicles, railway vehicles, golf carts, electric carts, electric cars (including hybrid vehicles), etc. can be cited, and they are used as the driving power source or auxiliary power source. As the power storage device, a power storage power source for buildings such as houses or for power generation equipment can be cited.

[0132] Refer to Figure 10 An example of applying the present invention to a power storage system for electric vehicles will be described. Figure 10 An example of the structure of a hybrid vehicle using a series hybrid system to which the present invention is applied is schematically shown. A series hybrid system is a vehicle that travels using the electric power generated by a generator driven by an engine or the electric power temporarily stored in a battery and utilizes an electric power driving force conversion device.

[0133] In this hybrid vehicle 600, an engine 601, a generator 602, an electric power driving force conversion device 603, a first drive wheel 6041, a second drive wheel 6042, a first wheel 6051, a second wheel 6052, a battery 608, a vehicle control device 609, various sensors 610, and a charging port 611 are mounted. The battery pack 430 of the present invention described above is applied to the battery 608.

[0134] The hybrid vehicle 600 travels using the electric power driving force conversion device 603 as the power source. An example of the electric power driving force conversion device 603 is a motor. By the electric power of the battery 608, the electric power driving force conversion device 603 operates, and the rotational force of the electric power driving force conversion device 603 is transmitted to the first drive wheel 6041 and the second drive wheel 6042. It should be noted that by using direct current - alternating current (DC - AC) or inverse conversion (AC - DC conversion) at necessary positions, the electric power driving force conversion device 603 can be applied to an AC motor or a DC motor. The various sensors 610 control the engine speed via the vehicle control device 609, or control the opening degree of a throttle valve (throttle opening) not shown. The various sensors 610 include a speed sensor, an acceleration sensor, an engine speed sensor, etc.

[0135] The rotational force of the engine 601 is transmitted to the generator 602, and by this rotational force, the electric power generated by the generator 602 can be stored in the battery 608.

[0136] When the hybrid vehicle 600 is decelerated by a braking mechanism not shown, the resistance during deceleration is applied as a rotational force to the electric power driving force conversion device 603, and the regenerative electric power generated by the electric power driving force conversion device 603 by this rotational force is stored in the battery 608.

[0137] The battery 608 can also receive power supply from an external power source through the charging port 611 as an input port by connecting to the external power source of the hybrid vehicle 600, and store the received power.

[0138] Although not shown, an information processing device for performing information processing related to vehicle control based on information related to the secondary battery may also be provided. As such an information processing device, for example, there is an information processing device that displays the battery remaining capacity based on information related to the remaining capacity of the battery.

[0139] It should be noted that the above has been described by taking a series hybrid vehicle that travels with a motor using the power generated by a generator driven by an engine or temporarily storing it in a battery as an example. However, the present invention can also be effectively applied to a parallel hybrid vehicle that uses both the output of the engine and the motor as drive sources and appropriately switches among three modes of traveling only by the engine, traveling only by the motor, and traveling by the engine and the motor. Furthermore, the present invention can also be effectively applied to a so-called electric vehicle that travels only by driving a motor without using an engine.

[0140] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments, and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent substitutions, and improvements made 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. The core is formed by winding a positive electrode sheet (13), a separator (15), a negative electrode sheet (14), and a separator (15) stacked in sequence. The positive electrode foil of the positive electrode sheet (13) has a positive electrode coating layer and a blank foil at the axial end of the core. The negative electrode foil of the negative electrode sheet (14) has a negative electrode coating layer and a blank foil at the axial end of the core. The blank foils of the positive electrode sheet (13) and the negative electrode sheet (14) face in opposite directions. It is characterized in that Either one or both of the blank foil of the positive electrode sheet (13) and the blank foil of the negative electrode sheet (14) have a flat surface (11) formed by bending and overlapping towards the central axis of the core, and a groove (112) is formed on the flat surface (11). The grooves (112) are radially spaced along the inner circumference to the outer circumference of the core on the flat surface (11). The number of the grooves (112) on the flat surface (11) is M. A bending area is formed on the outermost side of one or both of the blank foil on the positive electrode foil and the blank foil on the negative electrode foil. The bending width of the bending area is W. The theoretical depth D0 of the groove (112) = πW / M. The actual depth D of the groove (112) is configured such that 0.9D0 ≤ D ≤ 1.1D0.

2. The core according to claim 1, characterized in that, The actual depth D of the groove (112) is configured such that D = D0.

3. The core according to claim 1, characterized in that, 4 ≤ M ≤ 12. Preferably, M = 6 or 8.

4. The core according to claim 1, characterized in that, The total thickness of the positive electrode sheet (13), the negative electrode sheet (14), and the two separators (15) is set as Gap. Gap = T1 + T2 + 2*T3. n*Gap ≤ W < (n + 1)*Gap. T1 is the thickness of the positive electrode sheet (13), T2 is the thickness of the negative electrode sheet (14), T3 is the thickness of the separator (15), and n is the number of stacked layers of the designed foil material. 4 ≤ n ≤ 16.

5. The core according to claim 4, characterized in that, 6≤n≤13。 6. The core according to claim 1, wherein the blank foil of the positive electrode sheet (13) can be divided into a vertical area with a length L along the vertical direction of the core and the bending area. The physical stiffness of the vertical area is greater than that of the bending area.

7. The core according to claim 6, wherein the vertical area is selectively coated with a ceramic slurry or an insulating glue substance to increase the physical stiffness.

8. The core according to any one of claims 1-7, characterized in that, The diameter of the central hole of the core is R1, the outer diameter of the core is R4. The flat surface (11) forms a welding area (111), which is used for welding with the corresponding current collector (20). The welding area (111) is fan-shaped and concentrically arranged with the core. The outer diameter of the welding area (111) is R3, and the inner diameter of the welding area (111) is R2. R3 = R4 - W, R2 = R1 + W.

9. All-tab cylindrical battery, characterized in that, It includes the core according to claim 8 and two current collectors (20). The two current collectors (20) and the two flat surfaces (11) are arranged in one-to-one correspondence and are welded and connected on the welding area (111).

10. Electrical device, characterized in that, It includes the full - pole - ear cylindrical battery according to claim 9 and an electrical component. The full - pole - ear cylindrical battery is used to supply power to the electrical component.

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