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. The bending width of the bending area is W, the theoretical depth D0 of the groove is equal to piW / M, 4 < = M < = 12, and the real depth D of the groove is configured to be 0.9 D0 < = D < = 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

Technical Field

[0001] The present invention relates to the technical field of battery processing, and in particular to a winding core, a full-ear cylindrical battery and an electrical device. Background Art

[0002] Full-ear cylindrical batteries have greatly improved the battery's overcurrent capability, reduced the battery's heat generation, and broken through the bottleneck of cylindrical batteries, and therefore have attracted much attention. Leveling is a key process in the manufacturing process of cylindrical full-ear batteries. In order to facilitate the subsequent welding of the collectors at the ends of the battery and ensure the welding quality, the ends of the battery need to be leveled, and the upright ears of the cylindrical winding core are flattened into a plane so that each layer of ears is in close contact. The more mature methods on the market now are flattening and stacking. Flattening is highly destructive to the ears and is prone to produce metal debris. Self-discharge and internal shorts are prone to occur inside the battery. The stacking process is inefficient and has high process requirements. It is also easy to produce metal debris during the ear cutting process.

[0003] Relatively speaking, flattening is less destructive to the ear, less likely to produce metal debris, and has better safety performance, but the technical difficulty is high and the yield rate is low. The flattening technology has just started, and a large number of technical difficulties need to be overcome. One of the technical difficulties of flattening is that the flat surface of the core is formed by pressing multiple layers of pole pieces. The extension direction of the outer ring pole pieces before pressing is consistent with the axial direction of the core. After pressing, the top of the multi-layer pole pieces is pressed into the flat surface of the core. However, on the flat surface of the core, the stacking of multiple layers of pole pieces causes the flat surface after pressing to form more obvious wrinkles or plane collapse, and the flatness is very poor, which is not conducive to the welding of the flat surface and the current collector.

[0004] Therefore, it is urgent to design a rolled core, full-ear cylindrical battery and an electrical device to solve the above problems. Summary of the invention

[0005] One object of the present invention is to provide a winding core, the wrinkles on the flat surface of the winding core are significantly reduced, the flatness is improved, and the welding quality between the flat surface and the current collecting sheet is improved.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A winding core, wherein the winding core is formed by winding 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 located at the axial end of the winding core, the negative electrode foil of the negative electrode sheet has a negative electrode coating layer and a blank foil located at the axial end of the winding core, and the blank foils of the positive electrode sheet and the negative electrode sheet face opposite directions;

[0008] Either or both of the blank foil of the positive electrode sheet and the blank foil of the negative electrode sheet have a flat surface formed by being bent toward the central axis of the winding core and overlapped, and grooves are formed on the flat surface, and the grooves are radially spaced from the inner periphery to the outer periphery of the winding core on the flat surface;

[0009] The number of the grooves on the flat surface is M, which are formed on the outermost sides 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 zone is W. The theoretical depth of the groove is D0=πW / M, 4≤M≤12, and the actual depth D of the groove is configured to be 0.9D0≤D≤1.1D0.

[0010] As an optional solution, the actual depth D of the groove is configured as D=D0.

[0011] As an alternative, M=8.

[0012] As an optional scheme, the total thickness of the positive electrode sheet, the negative electrode sheet and the two layers of the separator is set to Gap, Gap=T1+T2+2*T3, n*Gap≤W<(n+1)*Gap, T1 is the thickness of the positive electrode sheet, T2 is the thickness of the negative electrode sheet, T3 is the thickness of the separator, n is the number of stacking layers of the designed foil, 4≤n≤16.

[0013] As an alternative, 6≤n≤13.

[0014] The blank foil of the positive electrode sheet can be divided into a vertical area with a length of L along the vertical direction of the winding core and the bending area. The physical rigidity of the vertical area is greater than the physical rigidity of the bending area.

[0015] The vertical area is optionally coated with ceramic slurry or insulating glue to increase physical rigidity.

[0016] As an optional scheme, the diameter of the center hole of the above-mentioned winding core is R1, the outer diameter of the above-mentioned winding core is R4, the above-mentioned flat surface forms a welding area, the above-mentioned welding area is used to weld with the corresponding collecting sheet, the above-mentioned welding area is fan-shaped and is arranged concentrically with the above-mentioned winding core, the outer diameter of the above-mentioned welding area is R3, and the inner diameter of the above-mentioned welding area is R2, R3=R4-W, R2=R1+W.

[0017] Another object of the present invention is to provide a full-ear cylindrical battery, in which the flat surface of the winding core has a higher flatness and the welding quality between the winding core and the current collecting sheet is higher, thereby improving the reliability of the battery.

[0018] To achieve this object, the present invention adopts the following technical solutions:

[0019] The full-tab cylindrical battery comprises the above-mentioned winding core and two current collecting sheets, wherein the two current collecting sheets and the two flat surfaces are arranged in one-to-one correspondence and are welded and connected on the above-mentioned welding area.

[0020] Another object of the present invention is to provide an electrical device, which has high power reliability and reduces safety risks for users by adopting the above-mentioned full-tab cylindrical battery.

[0021] To achieve this object, the present invention adopts the following technical solutions:

[0022] An electrical device comprises the above-mentioned full-tab cylindrical battery and an electrical component, wherein the above-mentioned full-tab cylindrical battery is used to supply power to the above-mentioned electrical component.

[0023] The beneficial effects of the present invention are:

[0024] The present invention provides a winding core, in which the depth of the groove is accurately calculated, and the residual material on the flat surface that is prone to wrinkles due to pressing is absorbed by the groove, thereby reducing the wrinkles on the remaining part of the flat surface except the groove position, thereby ensuring the flatness of the flat surface and improving the welding stability between the flat surface and the current collecting sheet.

[0025] The present invention also provides a full-ear cylindrical battery. By adopting the above-mentioned winding core, the wrinkles on the flat surface of the winding core are significantly reduced, the flatness of the winding core is higher, the welding quality of the current collector is higher, and the reliability of the battery is improved.

[0026] The present invention also provides an electrical device, which uses the full-ear cylindrical battery to power the electrical component, thereby improving the power consumption stability of the electrical component. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly and easily, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. The drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 is an exploded view of welding the winding core and two current collecting sheets provided by an embodiment of the present invention;

[0029] Figure 2 is a cross-sectional view of a winding core before pre-pressing provided by an embodiment of the present invention;

[0030] Figure 3 is a cross-sectional view of a rolled core after pressing provided by an embodiment of the present invention;

[0031] Figure 4 is a layered diagram of the interior of a winding core provided by an embodiment of the present invention;

[0032] Figure 5 is a schematic diagram of unfolding the positive electrode sheet and the negative electrode sheet provided by an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of partitions of a flat surface of a winding core provided by an embodiment of the present invention;

[0034] Figure 7 is a cross-sectional view of a rolled core cut at the position of a groove after being pressed provided by an embodiment of the present invention;

[0035] Figure 8 is a schematic diagram of a flat surface bending area of ​​a winding core provided in an embodiment of the present invention;

[0036] Fig. 9 is a working principle diagram of the electric screwdriver provided by an embodiment of the present invention;

[0037] Fig.10 It is a working principle diagram of an electric vehicle provided by an embodiment of the present invention.

[0038] In the figure:

[0039] 10. Roll core;

[0040] 11. flat surface; 111. welding area; 1111. welding line; 112. groove;

[0041] 13. positive electrode sheet; 131. positive electrode active material layer; 132. first blank foil; 14. negative electrode sheet; 15. separator;

[0042] 16. positive electrode flat surface; 17. negative electrode flat surface; 18. through hole;

[0043] 20. Current collector;

[0044] 430, battery pack; 431, electric screwdriver; 432, trigger switch; 433, motor; 434, shaft; 435, motor control unit;

[0045] 600, hybrid vehicle; 601, engine; 602, generator; 603, electric driving force 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 DESCRIPTION

[0046] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0047] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0050] like Figure 1 The structure of a full-ear cylindrical battery according to an embodiment of the present invention (only the winding core 10 and two current collectors 20 are shown), and see Figure 2 The winding core 10 is formed by winding the positive electrode sheet 13, the separator 15, the negative electrode sheet 14 and the separator 15 stacked in sequence, and the whole is cylindrical. Figure 2 As 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 unfolded, both ends of the positive electrode sheet 13 and the negative electrode sheet 14 in the width direction (i.e., the positions where the active material is not coated) form the aforementioned blank foil. Figure 2 As shown, taking the positive electrode sheet 13 as an example, the position on the positive electrode foil where the positive electrode active material layer 131 is not coated forms a first blank foil 132. Of course, see Figure 4 The portion of the negative electrode foil not coated with the negative electrode active material forms a second blank foil (not marked, Figure 4The center is located at the end of the winding core 10 away from the first blank foil 132). Figure 2 As shown, when the core 10 is wound, in the axial direction, the positive electrode active material layer 131 and the negative electrode active material layer (not shown in the figure) are staggered so that the blank foils of the positive electrode sheet 13 and the negative electrode sheet 14 are wound into the core 10 in opposite directions, and the upper and lower end surfaces (the lower end surface is not shown) are pressed into a flat surface 11 by a flattening device.

[0051] like Figure 1 and Figure 4 As shown, the winding core 10 is contained in a battery case (not shown) in a state of being impregnated with electrolyte. The positive electrode foil may be a metal foil made of aluminum or aluminum alloy, and the negative electrode foil may be a metal foil made of copper or copper alloy.

[0052] like Figure 2 As shown, in an optional embodiment, there is a through hole 18 in the central axis of the winding core 10, and the through hole 18 is used to insert a positioning pin (not shown in the figure), and the positioning pin is used for welding the current collector 20 and the bottom of the battery housing. Figure 3 and Figure 4 As shown, the positive electrode blank foil and the negative electrode blank foil are bent into a flat surface 11, and the bending direction is from the outer periphery of the winding core 10 toward the through hole 18, and the adjacent blank foils of the positive electrode sheet 13 or the negative electrode sheet 14 are bent to overlap each other. In the industry, it is usually required that when observed along the axial direction of the winding core 10, the blank foils on the flat surface 11 should overlap each other by at least 4 layers, so as 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 the inner peripheral ears, resulting in the need to accommodate more foil in the multiple bending areas of the inner circle, and the degree of extrusion of the bottom material area will be deepened, with the risk of material falling off. At the same time, there is a risk of internal short of the battery caused by the insertion of the ears, resulting in serious accidents. Figure 1 and Figure 3 As shown, in an optional embodiment, the current collector 20 is divided into a positive current collector and a negative current collector. The positive current collector is welded to the flat surface 11 formed by the positive blank foil. The positive current collector can be a metal plate or metal sheet made of a monomer or composite material of aluminum or aluminum alloy. The negative current collector is welded to the flat surface 11 formed by the negative blank foil. The negative current collector can be a metal plate or metal sheet made of a monomer or composite material of nickel, nickel alloy, copper, or copper alloy. A hole is opened near the center of the positive current collector 20, and the position of the hole is the position corresponding to the through hole 18. The negative current collector can be a whole circular current collector, or a circular current collector with a circular protrusion in the center. The center position of the current collector 20 at one end of the negative electrode is further welded to the bottom of the battery housing through an external positioning pin.

[0053] It is understandable that the present invention Figures 1 to 4They are only schematic diagrams. For example, the actual number of layers of the core 10 is subject to the embodiment. In an optional embodiment, the positive electrode active material layer 131 includes any one or more of the positive electrode materials that can embed and deintercalate lithium. The positive electrode active material layer 131 may also further include any one or more of other materials such as a positive electrode binder and a positive electrode conductor. The positive electrode material can be lithium iron phosphate or nickel-cobalt-manganese system, nickel-cobalt-aluminum system ternary material and other lithium-ion battery positive electrode materials already available in the prior art.

[0054] In an optional embodiment, the negative electrode material can be a carbon material, such as artificial graphite and natural graphite, or a graphite composite negative electrode material doped with a certain amount of silicon oxygen or silicon carbon, as well as other lithium-ion battery negative electrode materials available in the prior art.

[0055] In an optional embodiment, the diaphragm 15 can be a single-layer PP, a single-layer PE, a double-layer PP / PE, a double-layer PP / PP and a triple-layer PP / PE / PP; the diaphragm 15 can also be a porous membrane coated with ceramic particles, and the ceramic is preferably Al2O3 or boehmite; the diaphragm 15 can also be other lithium-ion battery diaphragm materials available in the prior art.

[0056] In an optional embodiment, the electrolyte includes a solvent and an electrolyte salt. In addition, the electrolyte may further include any one or more of other materials such as additives.

[0057] In an optional embodiment, the solvent includes any one or more non-aqueous solvents such as organic solvents. The electrolyte of the non-aqueous solvent is a so-called non-aqueous electrolyte, and the non-aqueous solvent can be, for example, cyclic carbonate, chain carbonate, lactone, chain carboxylic acid ester, nitrile (mononitrile), etc.

[0058] In an optional embodiment, the electrolyte salt may include any one or more of lithium salts, etc. In addition, the electrolyte salt may also include salts other than lithium salts, etc. The salts other than lithium salts may be light metal salts other than lithium, etc.

[0059] In one embodiment, the battery shell is a metal shell, which can be a steel shell or an aluminum shell, and is more preferably a steel shell. In one embodiment, the battery model is preferably a 18650 or 21700 cylindrical battery, but the present invention is not limited to the above two cylindrical batteries.

[0060] In an optional embodiment, the 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 hexafluorosilicate (Li2SF6), lithium chloride (LiCl) and lithium bromide (LiBr). Among them, the lithium salt can be any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate and lithium hexafluoroarsenate; the lithium salt more preferably includes lithium hexafluorophosphate. The content of the electrolyte salt is not particularly limited, and preferably 0.3 mol / kg to 3 mol / kg relative to the solvent.

[0061] The blank foil on the flat surface 11 and the blank foil in the groove are continuous and have not been cut by a cutting device or the like. The groove is obtained by pressing down the pressing claws of the flattening device.

[0062] In the prior art, since the positive electrode blank foil or the negative electrode blank foil bends inwardly, the circumferential dimensions of the blank foil before and after bending are reduced, which easily causes wrinkles on the flat surface 11 , which is not conducive to welding the flat surface 11 and the corresponding current collecting sheet 20 .

[0063] In order to solve the above problems, Figure 3-Figure 6 As shown, this embodiment provides a winding core 10, the wrinkles of the flat surface 11 of the winding core 10 are significantly reduced, the flatness of the flat surface 11 is significantly improved, and the welding quality between the flat surface 11 and the current collecting sheet 20 is improved. Figure 4 and Figure 6 As shown, the flat surface 11 is formed with grooves 112, and the grooves 112 are radially spaced from the inner periphery to the outer periphery of the winding core 10 on the flat surface 11; the number of the grooves 112 on the flat surface 11 is M, and a bending zone 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, and the bending width of the bending zone is W, the theoretical depth D0 of the groove 112 is πW / M, and the actual depth D of the groove 112 is configured to be 0.9D0≤D≤1.1D0.

[0064] It should be noted that the groove 112 and the flat surface 11 are formed on a flattening device.

[0065] As an embodiment, a typical flattening method of the flattening device can be a two-step flattening method:

[0066] 1. Pre-pressing - forming the groove 112, first pre-pressing the unbent blank foil on the unflattened winding core 10 to form the expected groove 112;

[0067] 2. Flattening - forming a flat surface 11 and a final groove 112, flattening the pre-pressed battery cell to obtain Figure 1 The flattened core 10 in the.

[0068] It is understandable that the groove structure mentioned in the present invention is based on the groove 112 of the final flattened core 10, and the groove structure includes the depth of the groove 112 and the width of the groove 112. Since the groove 112 formed during the pre-pressing process and the groove 112 of the final flattened core 10 may have slightly different structures, the groove 112 in the present invention is based on the groove 112 of the final flattened core 10. The flattened core 10 is also the final product of the flattening step, and the subsequent step is to weld it with the positive current collector and the negative current collector. It is understandable that, see Figure 2 and Figure 4 Taking the positive electrode flat surface 16 of the winding core 10 as an example, before pressing, the blank foil of the positive electrode foil extends along the axial direction of the winding core 10, and the top of the blank foil of the positive electrode foil (that is, the first blank foil 132) is flattened by the pressing tool (part of the first blank foil 132) to form the positive electrode flat surface 16. The flattened portion is the bent portion, and the length of the bent portion bent inward is W.

[0069] Among them, Figure 4 As shown, the blank foil of the positive electrode sheet 13 (also known as the first blank foil) and the blank foil of the negative electrode sheet 14 are discussed separately for positive and negative electrodes due to the different flattening structures. 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 structure, the negative electrode sheet 14 will be larger than the positive electrode sheet 13 in the width direction, and the entire negative electrode sheet 14 will cover the positive electrode sheet 13. Therefore, in the width direction of the electrode sheet (i.e. the length direction of the winding 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 blank foil of the entire positive electrode is L+W. Generally speaking, since the physical rigidity requirements of L1 and L2 are much greater than those of the W part, in the actual coil design, L2 will be coated with ceramic slurry or insulating glue and other materials to increase the rigidity of L2 to resist bending. At the same time, its insulating coating can effectively alleviate the internal short of the positive electrode sheet 13 and the negative electrode sheet 14. For the L1 part, as needed, we will also apply ceramic slurry or insulating glue and other materials to most or all areas of L1 to increase the rigidity of L1 to resist bending. The coating on L1 and the coating on L2 are continuous coatings, and the materials of the two can be the same and applied at the same time. It can be understood that the vertical area has stronger physical rigidity than the bending area, ensuring that the vertical area maintains a generally vertical direction during the flattening process to prevent excessive interference with the negative electrode sheet 14.

[0070] At the same time, if Figure 4 and Figure 6As shown, the outer vertical area L2 is arranged in this way to ensure that the projection of the positive electrode active material layer 131 completely falls into the negative electrode active material layer, thereby preventing the edge of the negative electrode sheet 14 from piercing the separator 15 and contacting the positive electrode active material layer 131 to cause a short circuit.

[0071] Through long-term practical exploration by technicians, when L1 / L2<0.2, the ratio is too small to effectively protect the negative electrode sheet 14, and it also affects the alignment accuracy of the winding (this part mostly considers the use of glue coating). When L1 / L2>2, the 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 used. Through this setting method, the negative electrode sheet 14 can be protected at the same time, the winding alignment accuracy is ensured, and the battery energy density will not be affected.

[0072] 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 larger 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, we can also divide the blank foil on the negative electrode side into the form of vertical area and bending area 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 apply ceramic slurry or insulating glue and other materials to increase the rigidity of L, but considering that during the flattening process, if the vertical area of ​​the negative electrode itself can meet the rigidity requirements of flattening, it is also possible not to apply ceramic slurry or insulating glue and other materials. The core reason is that the negative electrode side does not need to consider the problem of internal short caused by the negative electrode sheet 14 and the positive electrode touching each other, so the ceramic slurry or insulating glue coating on the negative electrode side is an option, which can be selected according to actual needs.

[0073] It should be noted that in actual products, the vertical area and the bending area can be directly connected or smoothly transitioned through a transition structure. In the present invention, a direct connection method is adopted.

[0074] In an optional embodiment, if Figure 4 As shown, a separator 15 is sandwiched between the adjacent negative electrode sheets 14 of each circle of positive electrode sheets 13, one end of the wound multi-layer positive electrode sheets 13 is pressed to form a flat surface 11 (positive electrode flat surface 16), and one end of the wound multi-layer negative electrode sheets 14 is pressed to form another flat surface 11 (negative electrode flat surface 17), W=n*Gap, Gap=T1+T2+2*T3, 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. Figure 4 Take this as an example to illustrate: Figure 3In the figure, the number of stacked layers of the positive electrode foil is 4, that is, the outermost positive electrode sheet 13 can be overlapped on the fifth positive electrode sheet 13 from the outside to the inside after being turned over, and the fillet is ignored. The length of W should cover the thickness of 4 negative electrode sheets 14, 4 positive electrode sheets 13 (half of each positive electrode sheet 13 on both sides) and 8 diaphragm 15 thicknesses, which just meets the stacking number of positive electrode foils of 4 layers. The stacking number of layers below 4 does not meet the welding conditions. When n is other values, it must be ensured that n*Gap≤W<(n+1)*Gap, Gap=T1+T2+2*T3, T1, T2 and T3 are all known, n is the designed number of foil stacking layers, and the value of W can be determined more conveniently, and then the value of D0 can be determined.

[0075] n*Gap≤W<(n+1)*Gap, n is the designed number of foil stacking layers, 4≤n≤16. This formula can be understood in this way. After designing the number of foil stacking layers, we can adjust the width W of the bending zone to meet the design of this number of stacking layers. For example, if the number of foil stacking layers is 6, then 6Gap≤W<7Gap. It can be recognized that the top of the first bending zone can reach the root of the seventh bending zone (at this time W=6Gap), or the top of the first bending zone can partially cover the area of ​​the seventh bending zone and does not reach the area of ​​the eighth bending zone. At this time, looking down from the entire flat surface, it can be found that the number of foil stacking layers is 6. When 6Gap≤W<7Gap, we can make the actual number of stacking layers of the entire flat surface (based on the welding area) at least reach 6 layers. In most cases, the actual number of stacking layers of the entire flat surface (based on the welding area) is between 6-7 layers (when 6Gap<W<7Gap). It meets the design requirements and can achieve the technical effects of the present invention.

[0076] In an optional embodiment, at least 4 layers of foil must be stacked to ensure sufficient welding depth during subsequent welding with the current collector 20, avoid welding penetration, and meet other welding indicators, so the lower limit n≥4 is set. Looking along the height direction of the core 10, the number of layers of blank foil stacked 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, resulting in welding failure, and it is very likely to cause the laser to weld through the ear and further damage the lower pole piece and diaphragm 15, resulting in more serious internal shorting of the core 10. At the same time, if the number of stacked layers of the ear used for welding is too small, its internal resistance will also increase, the welding tension will be too small and not up to standard, and the roller test will also fail. All point values ​​or ranges greater than or equal to 4 are within the protection range of this optional embodiment.

[0077] In an optional embodiment, as an extreme case, the technical effect of the present invention can be basically achieved while ensuring that 4 layers of foil are stacked, and the welding effect can also be basically satisfied. At this time, n=4, 4Gap≤W<5Gap, and it can be ensured that the actual stacking layers of the entire flat surface (based on the welding area) are 4 and 5 layers.

[0078] Therefore, n=4 also belongs to the protection scope of the present invention, and 4≤n≤16 in all embodiments of the present invention has taken into account the upper and lower limits of the foil stacking that can realize the technical solution of the present invention.

[0079] The total thickness of the positive electrode sheet 13, the negative electrode sheet 14 and the two layers of separator 15 is set to 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, n is the number of stacking layers of the designed foil, 4≤n≤16.

[0080] At the same time, considering that when n is too large, the foil near the inner circle of the winding core 10 will cause the pole piece stacking near the center to be more serious due to the excessive W value. This is mainly because the edge of the inner circle of the foil after the flanging can only be abutted against the positioning pin of the winding core 10 at the most central position. The inner foil flanging not only has more material in the circumferential direction, but also has more material in the radial direction due to the obstruction of the positioning pin. After flattening, the degree of foil extrusion will be deepened, damaging the negative electrode material area. In order to avoid the excessive W value, which will aggravate the foil material situation near the positioning pin, and considering the battery design efficiency and energy density, n is set to ≤ 16. Among them, n can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, etc., and 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.

[0081] For the sake of safety, in an optional embodiment, n≤13. In addition, when n≥6, the design of most of the cores 10 can be satisfied, so when n is in the range of 6 to 13, it is a more preferred solution. And within this range, the battery design efficiency and energy density are more optimized, and there are fewer cases of damage to the negative electrode material area, wherein n can be 6, 7, 8, 9, 10, 11, 12, 13, etc., and all point values ​​or ranges greater than or equal to 6 and less than or equal to 13 are within the protection range of this optional embodiment.

[0082] To better illustrate the process of confirming the depth of the groove, take the positive electrode sheet 13 as an example. Figure 2 Status to Figure 3 The state of each layer of positive electrode sheet 13 from before flattening to after flattening is equivalent to undergoing a "flanging" operation.

[0083] In an optional embodiment, if Figure 4 and Figure 7 As shown, taking the outermost ring of the positive electrode as an example, the width of the bending zone is W, and the bending zone includes the upper end (outer end) and the root, and the root is connected to the vertical zone. At this time, the circumference of the outermost ring of the pole ear around the winding core 10 is 2πR4. When the outermost ring of the pole ear is flattened, it folds inward, and the position where the upper end of the bending zone reaches is the position of R4-W. At this time, the circumference of the position of R4-W is 2π (R4-W). For the uppermost end of the outermost ring of the pole ear, it is obvious that there is an extra 2πR4-2π (R4-W) = 2πW of the pole ear margin. If this part of the pole ear is not processed, it is simply considered that "not processed" in the present invention means that the groove design is not performed, which will produce a large number of wrinkles on the flattened end surface, making the flatness of the flat surface 11 very poor, difficult to weld, and ultimately unable to achieve the purpose of the present invention. The above-mentioned wrinkles need to be offset by the groove 112 to absorb this part of the excess pole ear, and finally the flat surface 11 is flattened to form a smooth flat surface 11 without obvious defects. That is, the core 10 accurately calculates the depth of the groove 112, and the residual material on the flat surface 11 that is easy to cause wrinkles due to pressing is absorbed by the groove 112, thereby reducing the wrinkles on the flat surface 11 except the position of the groove 112, thereby 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, which will not be repeated here.

[0084] In an optional embodiment, if Figure 6 As 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 a rectangle. The groove 112 is generally a rectangular parallelepiped that is straight from the inner periphery to the outer periphery, and its position on the winding core 10 has the same depth from the inner periphery to the outer periphery. The groove 112 with a rectangular cross-section has a simple structure and is easy to process.

[0085] In an optional embodiment, the width of the groove 112 can be equal. However, other widths such as gradual widths, such as a bell-shaped shape, such as the groove 112 being wide at the outer periphery and narrow at the inner periphery, can also be used. The selection of the above widths will not affect the realization of the technical effects of the present invention. In fact, as long as the depth is equal, the width can be selected according to actual conditions.

[0086] In an optional embodiment, if Figure 7 As shown, the depth of the groove 112 is set to D, and a rectangular groove 112 has two (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, and finally D0=πW / M is obtained.

[0087] In an optional embodiment, the present invention further finds that the actual design can be designed around the point value of D0=πW / M. We find that D in the range of 0.9D0≤D≤1.1D0 can also achieve the technical effect of the present invention, which will be discussed in detail later. Wherein, 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 the optional embodiment.

[0088] In an optional embodiment, if Figure 6 As shown, for the number M of the grooves 112, generally a symmetrical number or a number that can equally divide the circumference can be selected. Generally speaking, the number M should be greater than or equal to 4. M can be selected 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 optional embodiment. Among them, based on the size of the commonly used model of the winding core 10, the number M of this optional embodiment can be selected as 6 or 8.

[0089] In an optional embodiment, if Figure 6 As shown, the grooves 112 on the flat surface 11 can be evenly arranged in the entire circumferential area, and the angles of the grooves 112 are the same, 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 collecting sheet 20. Of course, in other optional embodiments, it is not ruled out that some areas may not be arranged with grooves 112, or the grooves 112 may also be arranged in the form of unequal spacing, and the arrangement of different grooves 112 is within the protection scope of the present application.

[0090] In an optional embodiment, if Figure 6As shown, the arrangement of the grooves 112 should extend from the inner periphery of the core 10 to the outer periphery and run through the entire core 10. This design divides the flat surface 11 into several independent fan-shaped areas, which are used for welding with the current collector 20. These fan-shaped areas are called welding areas 111. These welding areas 111 can be identical and equivalent fan-shaped areas, which are identical, independent and not connected to each other. For example, in this embodiment, the preferred scheme is to divide it into eight fan-shaped welding areas 111 with equal areas by eight grooves 112 spaced at the same angle of 45°. In an optional embodiment, the degree of authenticity D is configured to be 0.9D0≤D≤1.1D0. When the value of D is D<0.9D0, we found through experiments, the experimental data is shown in Table 1, in comparative example 1, D=0.8D0, the flatness is 0.75mm, and the welding defect rate is 15.10%; in comparative example 2, D=0.85D0, the flatness is 0.61mm, and the welding defect rate is 8.23%; in embodiment 1, D=0.9D0, the flatness is 0.40mm, and the welding defect rate is 0.99%; in embodiment 2, D=0.95D0, the flatness is 0.32mm, and the welding defect rate is 0.30%; in embodiment 3, D=D0. The flatness is 0.2mm, and the welding defect rate is 0.10%; in Example 4, D=1.05D0, the flatness is 0.3mm, and the welding defect rate is 0.22%; in Example 5, D=1.1D0, the flatness is 0.38mm, and the welding defect rate is 0.38%; in Comparative Example 3, D=1.15D0, the flatness is 0.55mm, and the welding defect rate is 4.97%; in Comparative Example 4, D=1.2D0, the flatness is 0.70mm, 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 after the winding core 10 is welded with the two current collectors 20 to form a finished battery.

[0091] Table 1

[0092]

[0093] It can be seen from Table 1 that when D is less than 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 are piled on the flat surface 11. From the test results, the flat surface 11 of the winding core 10 has wrinkles after pressing, and its flatness is also poor, with a flatness range of 0.5-0.75mm. The welding defect rate is very high, reaching more than 3%; even when the flatness is above 0.61mm, the welding defect rate reaches more than 8.23%. When D>1.1D0, it also exceeds the expected threshold value, and the amount of the extra tabs used to absorb the flat surface 11 exceeds the limit, causing the tabs used to form the flat surface 11 to be dragged into the groove 112, resulting in the groove 112 grabbing the tabs from the flat surface 11. Visually, it can be seen that there is a pit 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 situation of "D<0.9D0". Although the overall feeling is slightly better than "D<0.9D0", the actual effect can also be seen that when D>1.1D0, the flatness of each flat surface 11 is 0.5mm-0.7mm, 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 0.4mm. Such a flatness is a more ideal welding plane, and the welding defect rate can be generally controlled within 1.0%.

[0094] 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 our expected flattening technical effect. Its flatness range is within 0.2mm-0.4mm, and the welding defect rate is within 1.0%, which meets the technical requirements of the present invention. Within this range, the welding task of the present invention can be efficiently achieved.

[0095] When the flatness of the core 10 is above 0.5mm, the flat surface 11 of the entire core 10 is basically in a state where it cannot be welded. If an attempt is made to forcibly weld the current collector 20 and the flat surface 11, a greater clamping force between the current collector 20 and the core 10 is required, as well as an increase in the laser penetration depth. Even so, this will lead to problems such as the effective welding line 1111 being too short, forming a cold weld, and too low tensile strength. All these problems lead to unqualified batteries after welding and cannot be transferred normally to subsequent processes. The present invention collectively refers to these unqualified welds as welding defective rates. For further understanding of 0.9D0≤D≤1.1D0, we can consider D=D0 to be a preferred embodiment of the present invention. However, for D at 0.9D0≤D≤1.1D0, the technical effect of the present invention can also be achieved, which is within the parameter range required by the present invention.

[0096] As a more preferred technical solution, 0.95D0≤D≤1.05D0. At this time, the flatness is better and can be within 0.32mm, and the welding defects are further reduced to within 0.30%, which can achieve better technical effects.

[0097] In short, when 0.9D0≤D≤1.1D0, the flatness of the winding core 10 can achieve the technical effect of the present invention, can significantly reduce wrinkles, the flatness of the winding core is higher, and the welding quality of the final current collector 20 is higher, and the reliability of the battery is also significantly improved.

[0098] Combination Figure 6 The flatness of the flat surface 11 is obtained as follows: Figure 6 As shown, in the experiment, a 3D profilometer is used to test the flatness of the flat surface 11 of the core 10. The plane to be measured is selected, and the machine identifies the highest point and the lowest point of the selected area, and automatically calculates the difference between the high and low points, that is, the flatness.

[0099] The calculation formula for flatness is as follows:

[0100] F=H1-H2;

[0101] Among them, 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 of the test area of ​​the flat surface 11 of the core 10, and H2 is the height of the lowest point of the test area of ​​the flat surface 11 of the core 10. Figure 6 The shaded area in the middle is the eight overall plane areas measured. In a specific embodiment, the flatness measured by the present invention is the flatness of the entire battery cell end face (including the eight welding areas).

[0102] For example, Figure 6 The shaded part in the middle refers to the eight welding areas 111 measured. The eight welding areas 111 are used to be welded with the corresponding current collecting pieces 20. A person 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.

[0103] In an optional embodiment, if Figure 7 and Figure 8 As shown, the diameter of the central hole of the winding core 10 is R1, the outer diameter of the winding core 10 is R4, and the flat surface 11 forms a welding area 111, which is used to weld with the corresponding current collecting sheet 20. The welding area 111 is annular and concentrically arranged with the winding core 10. 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. In this case, Figure 6 The fan-shaped outer and inner peripheries 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.

[0104] 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.

[0105] 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.

[0106] 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 welding wires 1111 and slots 112 is set to eight. In other embodiments, it can be understood that the present invention does not require all welding areas 111 to be welded, and the number of welding wires 1111 can also be less than the number of welding areas 111, and can also be 3, 4, 5, 6 or 7, etc., which is not limited here.

[0107] For a specific embodiment, detailed specific parameters are given:

[0108] Core 10 size, R1=1.5mm, R4=10.2mm;

[0109] W=n*Gap, Gap=T1+T2+2*T3, T1=85μm, T2=80μm and T3=12μm, 1Gap=189μm, n=11, and the value of W=1.89mm is obtained.

[0110] The positive electrode has L1=1.8mm, L2=1.3mm, Lpositive=3.1mm and W=1.89mm, and the total height of the first blank foil 132 is L+W=4.99mm; the negative electrode has Lneg=1.4mm and W=1.89mm, and the total height of the blank foil is L+W=3.29mm;

[0111] The inner diameter R1=1.5mm, the outer diameter is 10.2mm, therefore, the weldable area 111 is in the range of R1+w to R4-W, so the weldable area 111, from the inner periphery to the outer periphery of the winding core 10, ranges from R2=R1+w to R3=R4-W, and the value is R2=3.39mm~R3=8.31mm. The value of M is 8; D0=πW / M=0.742mm.

[0112] Our selection range is 0.9D0≤D≤1.1D0, in this embodiment, 0.668mm≤D≤0.816mm;

[0113] In a preferred embodiment of the present invention, we select D=D0, then D=0.742mm.

[0114] In another embodiment, we select D=1.02D0, then D=0.757mm; in another embodiment, we select D=0.96D0, then D=0.712mm.

[0115] For another specific embodiment, detailed specific parameters are given:

[0116] Core 10 size, R1=1.5mm, R4=10.2mm;

[0117] W=n*Gap, Gap=T1+T2+2*T3, T1=85μm, T2=80μm, T3=12μm, 1Gap=189μm, n=8, and the final measured value is W=1.323mm.

[0118] The positive electrode has L1=1.8mm, L2=1.3mm, Lpositive=3.1mm and W=1.323mm, and the total height of the first blank foil 132 is Lpositive+W=4.423mm; the negative electrode has Lneg=1.4mm and W=1.323mm, and the total height of the blank foil is Lneg+W=2.723mm;

[0119] The inner diameter R1=1.5mm, the outer diameter is 10.2mm, therefore, the weldable area 111 is in the range of R2=R1+w to R3=R4-W, so the weldable area 111, from the inner periphery to the outer periphery of the winding core 10, ranges from R2=R1+w to R3=R4-W, and the value is 2.823mm-8.877mm. The value of M is 6; D0=πW / M=0.692mm, wherein 0.9D0≤D≤1.1D0, in this embodiment, 0.623mm≤D≤0.761mm.

[0120] In a preferred embodiment of the present invention, we select D=D0, then D=0.692mm.

[0121] In another embodiment, we select D=1.06D0, then D=0.734mm; in another embodiment, we select D=0.92D0, then D=0.637mm.

[0122] This embodiment also provides a full-ear tab cylindrical battery, comprising the above-mentioned winding core 10 and two current collecting sheets 20, wherein the two current collecting sheets 20 and the two flat surfaces 11 are arranged in one-to-one correspondence and connected by welding. By adopting the above-mentioned winding core 10, the flatness of the winding core 10 is higher, the welding quality of the current collecting sheets 20 is higher, and the reliability of the battery is improved.

[0123] This embodiment also provides an electric device, including the above-mentioned full-tab cylindrical battery and an electric component, wherein the full-tab cylindrical battery is used to power the electric component. The electric device uses the above-mentioned full-tab cylindrical battery to power the electric component, thereby improving the power consumption stability of the electric component.

[0124] In an optional embodiment, the electrical component may be an electronic device, such as 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 camcorder, a digital camera, an electronic 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, an electric tool, an electric shaver, a refrigerator, an air conditioner, a television, a stereo, a water heater, a microwave oven, a dishwasher, a washing machine, a dryer, lighting equipment, toys, medical equipment, a robot, a load regulator, a signal machine, etc.

[0125] Reference Fig. 9 , an example of an electric tool, such as an electric screwdriver, to which the present invention can be applied is briefly described. The electric screwdriver 431 has a motor 433 such as a DC motor housed in the main body. The rotation of the motor 433 is transmitted to a shaft 434, and the screw is screwed into the object through the shaft 434. The electric screwdriver 431 is provided with a trigger switch 432 operated by the user.

[0126] A battery pack 430 (the battery pack 430 may be composed of a plurality of full-ear cylindrical batteries) and a motor control unit 435 are housed in the lower frame of the handle of the electric screwdriver 431. 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 may also be controlled by the motor control unit 435. Although not shown in the figure, the battery pack 430 and the electric screwdriver 431 are engaged by being provided with engaging parts in each. As described later, the battery pack 430 and the motor control unit 435 each have a microcomputer. Battery power is supplied from the battery pack 430 to the motor control unit 435, and information about the battery pack 430 is communicated between the microcomputers of both.

[0127] The battery pack 430 can be freely attached and detached from the electric screwdriver 431, for example. The battery pack 430 can also be built into the electric screwdriver 431. The battery pack 430 is installed in the charging device when charging. It should be noted that when the battery pack 430 is installed in the electric screwdriver 431, a part of the battery pack 430 is exposed to the outside of the electric screwdriver 431, and the user can visually identify the exposed part. For example, an LED can also be provided on the exposed part of the battery pack 430 so that the user can confirm whether the LED is lit or not.

[0128] The motor control unit 435 controls the rotation, stop, and rotation direction of the motor 433. Furthermore, the power supply to the load is cut off when over-discharge occurs. The trigger switch 432 is inserted between the motor 433 and the motor control unit 435, for example. When the user presses the trigger switch 432, the motor 433 is powered and rotates. When the user returns the trigger switch 432, the rotation of the motor 433 stops.

[0129] In an optional embodiment, the electric component may be an electric vehicle. Examples of electric vehicles include railway vehicles, golf carts, electric carts, electric vehicles (including hybrid electric vehicles), etc., and the electric component may be used as a driving power source or auxiliary power source for the electric components. Examples of power storage devices include power sources for buildings such as residences or power generation equipment.

[0130] Reference Fig.10 An example in which the present invention is applied to a power storage system for an electric vehicle will be described. Fig.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. The series hybrid system is a vehicle that runs using electric power generated by a generator driven by an engine or electric power temporarily stored in a battery using an electric driving force conversion device.

[0131] The hybrid vehicle 600 is equipped with an engine 601, a generator 602, an electric power 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. The battery pack 430 of the present invention is applied to the battery 608.

[0132] The hybrid vehicle 600 travels using an electric driving force conversion device 603 as a power source. An example of the electric driving force conversion device 603 is a motor. The electric driving force conversion device 603 operates with the power of a battery 608, and the rotational force of the electric driving force conversion device 603 is transmitted to a first drive wheel 6041 and a second drive wheel 6042. It should be noted that the electric driving force conversion device 603 can be applied to an AC motor or a DC motor by using direct current-alternating current (DC-AC) or reverse conversion (AC-DC conversion) at necessary positions. Various sensors 610 control the engine speed via a vehicle control device 609, or control the opening of a throttle valve (throttle opening) not shown. Various sensors 610 include a speed sensor, an acceleration sensor, an engine speed sensor, and the like.

[0133] The rotational force of the engine 601 is transmitted to the generator 602 , and the electric power generated by the generator 602 can be stored in the battery 608 by the rotational force.

[0134] When the hybrid vehicle 600 is decelerated by a brake mechanism (not shown), the resistance during deceleration is applied to the electric driving force conversion device 603 as a rotational force, and the regenerative electric power generated by the electric driving force conversion device 603 by the rotational force is stored in the battery 608 .

[0135] Battery 608 is connected to a power source external to hybrid vehicle 600 , and can receive power from the external power source using charging port 611 as an input port, and can store the received power.

[0136] Although not shown, an information processing device that performs vehicle control based on information about the secondary battery may be provided. Examples of such an information processing device include an information processing device that displays the remaining battery level based on information about the remaining battery level.

[0137] It should be noted that the above description is based on a series hybrid vehicle that uses the power generated by the generator driven by the engine or the power temporarily stored in the battery and is driven by a motor. However, the present invention can also be effectively applied to a parallel hybrid vehicle that uses the output of both the engine and the motor as a driving source and appropriately switches between three modes of driving only by the engine, driving only by the motor, and driving by the engine and the motor. Furthermore, the present invention can also be effectively applied to so-called electric vehicles that are driven only by the drive motor without using an engine.

[0138] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A winding core, wherein the winding 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) having a positive electrode coating layer and a blank foil located at an axial end of the winding core, the negative electrode foil of the negative electrode sheet (14) having a negative electrode coating layer and a blank foil located at an axial end of the winding core, and the blank foils of the positive electrode sheet (13) and the negative electrode sheet (14) facing opposite directions; It is characterized in that Either 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 toward the central axis of the winding core and overlapping, and grooves (112) are formed on the flat surface (11), and the grooves (112) are radially spaced from the inner circumference to the outer circumference of the winding core on the flat surface (11); The number of the grooves (112) on the flat surface (11) is M, a bending zone is formed at 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 zone is W, the theoretical depth D0 of the groove (112) is D0=πW / M, 4≤M≤12, and the actual depth D of the groove (112) is configured to be 0.9D0≤D≤1.1D0.

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

3. The winding core according to claim 1, characterized in that: M=6 or 8.

4. The winding 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 layers of the separator (15) is set to 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), n is the number of stacked layers of the designed foil, 4≤n≤16.

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

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

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

9. Full-ear cylindrical battery, characterized in that: It comprises the winding core as claimed in claim 8 and two current collecting sheets (20), wherein the two current collecting sheets (20) and the two flat surfaces (11) are arranged in one-to-one correspondence and are welded and connected at the welding area (111).

10. An electrical device, characterized in that: It comprises the full-tab cylindrical battery as claimed in claim 9 and an electrical component, wherein the full-tab cylindrical battery is used to supply power to the electrical component.

Images