Winding core, all-pole-tab cylindrical battery, and electrical device

Abstract

The present invention belongs to the technical field of battery processing, and discloses a wound core, an all-pole-tab cylindrical battery, and an electrical device. The wound 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 wound core, and 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 wound core; either one or both of the blank foils of the positive electrode and the blank foils of the negative electrode have a flat surface formed by bending and overlapping towards the central axis of the wound core, and a groove is formed on the flat surface. The number of grooves on the flat surface is M, a blank foil bending area is formed on the outermost side of one or both of the blank foils of the positive electrode foil and the blank foils of the negative electrode foil, the bending width of the bending area is W, the theoretical depth D0 of the groove = πW / M, 4 ≤ M ≤ 12, and the actual depth D of the groove is configured such that 0.9D0 ≤ D ≤ 1.1D0, so that the wrinkles on the flat surface of the wound core are significantly reduced, and the welding quality between the flat surface and the current collector is improved.

Description

Technical Field

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

[0002] The full-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 process of the cylindrical full-tab battery. 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 tabs standing upright on the cylindrical core into a plane, and make the tabs of each layer in close contact. At present, the more mature methods in the market are kneading and cutting and stacking. Kneading has strong destructiveness to the tabs, and it is extremely easy to generate metal debris, which easily causes 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.

[0003] Relatively speaking, pressing has weak destructiveness to the tabs, is 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 electrode sheet before pressing is the same as the axial direction of the core. 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 the 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.

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

[0005] 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 improved.

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

[0007] 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 located 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 located at the axial end of the core. The blank foils of the positive electrode sheet and the negative electrode sheet face in opposite directions;

[0008] 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 grooves are formed on the flat surface. The grooves are radially spaced along the inner circumference to the outer circumference of the core on the flat surface;

[0009] 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 blank foil of the negative electrode foil. The bending width of the bending area is W, and the theoretical depth of the groove is D 0 = πW / M, 4 ≤ M ≤ 12. The actual depth D of the groove is configured to be 0.9D 0 ≤ D ≤ 1.1D 0 。

[0010] As an alternative, the actual depth D of the groove is configured to be D = D 0 。

[0011] As an alternative, M = 8.

[0012] 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, and n is the stacking number of the designed foils, 4 ≤ n ≤ 16.

[0013] As an alternative, 6 ≤ n ≤ 13.

[0014] The blank foil of the above-mentioned positive electrode sheet can be divided into a vertical area with a length of L in the vertical direction of the core and the above-mentioned bending area. The physical stiffness of the vertical area is greater than that of the bending area.

[0015] The vertical area is selectively coated with ceramic slurry or insulating glue material to increase the physical stiffness.

[0016] 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, and 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, R2 = R1 + W.

[0017] 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.

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

[0019] The all-pole-tab cylindrical battery includes the above-mentioned wound core and two current collectors, and 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.

[0020] Another object of the present invention is to provide an electrical device. By adopting the above-mentioned all-pole-tab cylindrical battery, the electrical reliability of the electrical device is high, and the safety risk of users is reduced.

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

[0022] The electrical device includes the above-mentioned all-pole-tab cylindrical battery and electrical components, and the above-mentioned all-pole-tab cylindrical battery is used to supply power to the above-mentioned electrical components.

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

[0024] The present invention provides a wound core. By accurately calculating the depth of the groove, the flat surface absorbs the surplus material that is prone to wrinkles caused by 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.

[0025] The present invention also provides an all-pole-tab cylindrical battery. By adopting the above-mentioned wound core, the wrinkles on the flat surface of the wound core are significantly reduced, the flatness of the wound 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. By using the above-mentioned all-pole-tab cylindrical battery to supply power to electrical components, the electrical stability of the electrical components is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

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

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

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

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

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

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

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

[0035] Figure 8 It is a schematic diagram of the bent area of the flat surface of the core provided by an embodiment of the present invention;

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

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

[0038] In the figure:

[0039] 10. Core;

[0040] 11. Flat surface; 111. Welding area; 1111. Welding wire; 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. 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

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of description, only the parts related to the present invention are shown in the drawings, rather than all the structures.

[0047] In the description of the present invention, unless otherwise clearly defined 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 integrated; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can 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 situations.

[0048] 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" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "under", and "beneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0049] 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. It is 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. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and do not have special meanings.

[0050] As Figure 1 shown in the structure of the all - tab cylindrical battery of an embodiment of the present invention (only the winding core 10 and two current collectors 20 are shown), and also referring to Figure 2 , the winding 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 integrally cylindrical. 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, 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) form the aforementioned blank foils. As Figure 2As shown, taking the positive electrode plate 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, reference can be made to Figure 4 The part where the negative electrode active material is not coated on the negative electrode foil forms a second blank foil (not labeled, Figure 4 which is located at one end of the core 10 away from the first blank foil 132). As Figure 2 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 plate 13 and the negative electrode plate 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 a flat surface 11 by a flattening device.

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

[0052] As Figure 2 shown, in an optional 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 used to be inserted into the through hole 18, and the positioning pin is used 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 a flat surface 11, and the bending direction is from the outer periphery of the core 10 towards the through hole 18, and the adjacent blank foils of the positive electrode plate 13 or the negative electrode plate 14 are bent overlapping each other. In the industry, it is usually 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, 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 tabs, which will lead to the need to accommodate more foil materials in the inner ring multiple bending area, deepen the extrusion degree of the bottom material area, there is a risk of material dropping, and at the same time there is a risk of inner insertion of the tabs causing internal short circuit of the battery, resulting in serious accidents. As Figure 1 and Figure 3As 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 sheet made of a single body or composite material of aluminum, aluminum alloy, etc. 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 sheet made of a single body or composite material of nickel, nickel alloy, copper, copper alloy, etc. A hole is provided near the center of the positive current collector 20, and the position of the hole corresponds to the position of the through hole 18. The negative current collector can be a circular current collector as a whole or a circular current collector with a circular convex portion in the center. The center position of the current collector 20 at the negative end is further welded to the bottom of the battery case through an externally inserted positioning pin.

[0053] It can be understood that Figures 1 to 4 in the present invention are only schematic diagrams. For example, the actual number of layers of the winding core 10 is subject to the embodiment. In an optional embodiment, the positive active material layer 131 includes any one or two or more of the positive electrode materials capable of intercalating and deintercalating lithium. The positive active material layer 131 may further include any one or two or more of other materials such as a positive electrode binder and a positive electrode conductive agent. The positive electrode material can 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.

[0054] In an optional embodiment, the negative electrode material can 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.

[0055] In an optional embodiment, the separator 15 can 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 can also be a porous membrane coated with ceramic particles, and the ceramic is preferably Al 2 O 3 or boehmite; the separator 15 can also be other separator materials for lithium ion batteries existing 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 two or more of other materials such as additives.

[0057] In an optional embodiment, the aforementioned solvent includes any one or two or more 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 can be, for example, cyclic carbonates, chain carbonates, lactones, chain carboxylic acid esters, nitriles (mononitriles), etc.

[0058] In an optional embodiment, the foregoing electrolyte salt may include, for example, any one or more 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.

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

[0060] In an optional embodiment, the foregoing lithium salt is, for example, lithium hexafluorophosphate (LiPF 6 )、lithium tetrafluoroborate (LiBF 4 )、lithium perchlorate (LiClO 4 )、lithium hexafluoroarsenate (LiAsF 6 )、lithium tetraphenylborate (LiB(C 6 H 5 ) 4 )、lithium methanesulfonate (LiCH 3 SO 3 )、lithium trifluoromethanesulfonate (LiCF 3 SO 3 )、lithium tetrachloroaluminate (LiAlCl 4 )、lithium bis(hexafluorosilicate) (Li 2 SF 6 )、lithium chloride (LiCl) and lithium bromide (LiBr), etc. Among them, the foregoing lithium salt may be any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate; the foregoing 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.

[0061] 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.

[0062] 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.

[0063] 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 andFigure 6 As shown, a flat surface 11 is formed with grooves 112 which 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 of the positive electrode foil and the blank foil of the negative electrode foil, the bending width of the bending area is W, and the theoretical depth D of the groove 112 0 = πW / M, and the actual depth D of the groove 112 is configured to be 0.9D 0 0.9D ≤ D ≤ 1.1D 0 .

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

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

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

[0067] 2. Flattening - forming the flat surface 11 and the final groove 112. Flatten the pre-pressed battery cell to obtain the Figure 1 flattened core 10 as shown.

[0068] It can be understood that the groove structures mentioned in the present invention are all based on the groove 112 of the finally flattened 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 core 10 may be slightly different, therefore, the groove 112 in the present invention is all based on the groove 112 of the finally flattened core 10, and the flattened 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 core 10 as an example, before pressing, the blank foil of the positive electrode foil extends along the axial direction of the core 10, and the top of the blank foil of the positive electrode foil (i.e., the first blank foil 132) is flattened by the pressing tooling (part of the first blank foil 132) to form the positive flat surface 16, and the flattened part is the bent part, and the length of the inward bending of the bent part is W.

[0069] Among them, as shown in Figure 4As shown, due to the different flattening structures of the blank foils of the positive electrode sheet 13 (i.e., the first blank foil) and the negative electrode sheet 14, we will discuss them 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 will be wider 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 the outer vertical area L1 and the inner vertical area L2, L = L1 + L2, and the blank foil of the entire 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, in actual winding design, 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 at the same time. 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.

[0070] At the same time, as Figure 4 and Figure 6 shown, setting the outer vertical area L2 in this way can ensure that the projection of the positive electrode active material layer 131 completely falls into 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.

[0071] Through the long-term practical exploration of 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 has an impact on the winding alignment accuracy (this part mainly considers the method of applying glue). When L1 / L2 > 2, this ratio is too large, and 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 at the same time, ensuring the winding alignment accuracy, and the energy density of the battery 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 wider than the positive electrode sheet 13 in the width direction. On the negative electrode side, such a 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 a vertical area and a bent area in the form of 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 that during the flattening process, if the vertical area 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.

[0073] It should be noted that in the actual product, the vertical area and the bent area can be directly connected or can be smoothly transitioned through a transition structure. In the present invention, a directly connected manner is adopted.

[0074] In an optional embodiment, as Figure 4 shown, a separator 15 is interposed 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 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 3 in, the stacking layer number of the foil of the positive electrode is 4 layers, that is, the outermost positive electrode sheet 13 can overlap the fifth positive electrode sheet 13 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, the thicknesses of 4 positive electrode sheets 13 (each of the two positive electrode sheets 13 on both sides takes half), and the thicknesses of 8 separators 15, just meeting the requirement that the stacking layer number of the foil of the positive electrode is 4 layers. Stacking layer numbers less than 4 do not meet the welding conditions. When n is other values, it is necessary to ensure that n * Gap ≤ W < (n + 1) * Gap, Gap = T1 + T2 + 2 * T3. T1, T2, and T3 are all known, and n is the designed stacking layer number of the foil, and the value of W can be determined more conveniently, and then the value of D 0 can be determined.

[0075] n * Gap ≤ W < (n + 1) * Gap, where n is the designed number of stacked foil layers, and 4 ≤ n ≤ 16. This formula can be understood as follows: after determining the designed number of stacked foil layers, we can adjust the width W of the bending area to meet the design requirements of this number of stacked layers. For example, when the number of stacked foil layers is 6, then 6Gap ≤ W < 7Gap. It can be realized that the uppermost end of the bending area of the first layer can reach the root of the bending area of the seventh layer (when W = 6Gap), or the uppermost end of the bending area of the first layer can partially cover the area of the bending area of the seventh layer and not reach the area of the bending area of the eighth layer. At this time, when looking down from the entire flat surface, it can be found that when the number of stacked foil layers is 6 and 6Gap ≤ W < 7Gap, we can ensure that the actual number of stacked layers of the entire flat surface (taking the welding area as the standard) is at least 6 layers, and in most cases, the actual number of stacked layers of the entire flat surface (taking the welding area as the standard) is between 6 and 7 layers (when 6Gap < W < 7Gap). This meets the design requirements and can achieve the technical effects of the present invention.

[0076] In an alternative embodiment, at least 4 layers of foils need to be stacked to ensure sufficient welding depth during subsequent welding with the current collector 20, avoid welding through, and meet other welding indicators. Therefore, the lower limit n ≥ 4 is set. Looking along the height direction of the core 10, the number of mutually stacked 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 the 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 test will also fail. All point values or ranges greater than or equal to 4 are within the protection scope of this alternative embodiment.

[0077] In an alternative embodiment, in the extreme case, when ensuring 4 layers of foils are stacked, the technical effects of the present invention can also be basically achieved, and the welding effect can also basically meet the requirements at this time. At this time, n = 4, 4Gap ≤ W < 5Gap, and at this time, it can be ensured that the actual number of stacked layers of the entire flat surface (taking the welding area as the standard) is 4 layers and 5 layers.

[0078] 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.

[0079] The total thickness of the positive electrode sheet 13, the negative electrode sheet 14, and the two separators 15 is set to 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, T3 is the thickness of the separator 15, n is the designed number of stacked foils, and 4 ≤ n ≤ 16.

[0080] Meanwhile, considering that when n takes a too large value, the foil near the inner circle of the core 10 will have a too large W value, resulting in a more serious pole piece stacking situation near the center. This is mainly because the position closest to the center of the edge after flanging of the inner circle foil can only abut against the positioning pin of the core 10. For the foil closer to the inside, there is excess material not only in the circumferential direction after flanging but also in the radial direction due to the blockage of the positioning pin. After being flattened, it will lead to a deeper extrusion degree of the foil, damaging the negative electrode material area. To avoid the aggravation of the excess material situation of the foil near the positioning pin caused by too large a W value, and considering the battery design efficiency and energy density, 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.

[0081] For the sake of 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 to 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.

[0082] 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 from before being flattened to after being flattened is equivalent to undergoing a "flanging" operation.

[0083] In an optional embodiment, such as Figure 4 and Figure 7As 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 upper 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 upper end of the outermost ear, it obviously has an ear margin 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 surface, 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 excess ear, and finally the flattened flat surface 11 forms a smooth and defect-free flat surface 11. That is, the winding core 10 accurately calculates the depth of the groove 112, and the excess 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 the position of the groove 112, and then 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.

[0084] 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 shows the same depth 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.

[0085] In an alternative embodiment, for the width of the groove 112, it 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 same depth is ensured, the width can be selected according to the actual situation.

[0086] 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, and finally D 0 = πW / M.

[0087] In an alternative embodiment, the present invention further discovers that the actual design can be centered around D0 Designing based on the value of = πW / M, we find that 0.9D 0 ≤ D ≤ 1.1D 0 D within this range can also achieve the technical effects of the present invention, which will be discussed in detail later. Among them, D can be 0.9D 0 , 0.91D 0 , 0.92D 0 , 0.93D 0 , 0.94D 0 , 0.95D 0 , 0.96D 0 , 0.97D 0 , 0.98D 0 , 0.96D 0 , D 0 , 1.01D 0 , 1.02D 0 , 1.03D 0 , 1.04D 0 , 1.05D 0 , 1.06D 0 , 1.07D 0 , 1.08D 0 , 1.09D 0 , 1.1D 0 etc., all point values or ranges greater than or equal to 0.9D 0 and less than or equal to 1.1D 0 are within the protection scope of this optional embodiment.

[0088] In an optional 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 optional embodiment. Among them, starting from the size of the commonly used core 10, the number M of this optional embodiment can be selected as 6 or 8.

[0089] In an optional embodiment, as Figure 6As shown, the slots 112 on the flat surface 11 can be evenly arranged in the entire circumferential region, with the same angular spacing 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 slots 112 may not be arranged in some areas, or the slots 112 may also be arranged in a non-uniform spacing form, and different arrangements of the slots 112 are within the protection scope of this application.

[0090] In an alternative embodiment, as Figure 6 shown, 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 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 and not connected to each other. For example, in this embodiment, the preferred solution is that the slots 112 are spaced at the same angle of 45° from each other, dividing the flat surface into eight congruent fan-shaped welding regions 111. In an alternative embodiment, the authenticity D is configured to be 0.9D 0 ≤D≤1.1D 0 . When the value of D is D < 0.9D 0 , we found through experiments that the experimental data are shown in Table 1. In Comparative Example 1, D = 0.8D 0 , the flatness is 0.75 mm, and the welding defect rate is 15.10%. In Comparative Example 2, D = 0.85D 0 , the flatness is 0.61 mm, and the welding defect rate is 8.23%. In Example 1, D = 0.9D 0 , the flatness is 0.40 mm, and the welding defect rate is 0.99%. In Example 2, D = 0.95D 0 , the flatness is 0.32 mm, and the welding defect rate is 0.30%. In Example 3, D = D 0 . The flatness is 0.2 mm, and the welding defect rate is 0.10%. In Example 4, D = 1.05D 0 , the flatness is 0.3 mm, and the welding defect rate is 0.22%. In Example 5, D = 1.1D 0 , the flatness is 0.38 mm, and the welding defect rate is 0.38%. In Comparative Example 3, D = 1.15D 0 , the flatness is 0.55 mm, and the welding defect rate is 4.97%. In Comparative Example 4, D = 1.2D 0, 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 to the number of tested batteries after the core 10 is welded to the two current collectors 20 to form a finished battery.

[0091] Table 1

[0092]

[0093] As can be seen from Table 1, when D < 0.9D 0 , 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 the core 10 is pressed, and its flatness is also poor. The flatness range is 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 > 1.1D 0 , it also exceeds the expected threshold, and the amount for absorbing 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 where 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 < 0.9D 0 ", although the overall feeling is slightly better than "D < 0.9D 0 ", but in the actual effect, it can also be seen that when D > 1.1D 0 , 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%.

[0094] When we choose 0.9D 0 ≤ D ≤ 1.1D 0 , from the test results, we can see that the entire flat surface 11 is flat without obvious defects, achieving the technical effect of flattening as expected. 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.

[0095] When the flatness of the core 10 is above 0.5 mm, the flat surface 11 of the entire core 10 is basically in a state where it cannot be welded. If one forcibly attempts to weld the current collector 20 and the flat surface 11, a greater pressing force between the current collector 20 and the core 10 is required, as well as an increase in the penetration depth of the laser, etc. Even so, it will still lead to problems such as an overly short effective bonding wire 1111, formation of a false weld, and an excessively small tensile strength. All these problems result in a non - qualified battery after welding, and it cannot be normally transferred to the subsequent processes. The present invention collectively refers to these non - qualified welds as the welding defect rate. Further, for 0.9D 0 ≤D≤1.1D 0 In our understanding, we can consider D = D 0 which belongs to a preference of the present invention. However, for D within the range of 0.9D 0 ≤D≤1.1D 0 the technical effects of the present invention can also be achieved, which falls within the parameter range required by the present invention.

[0096] As a more preferred technical solution, 0.95D 0 ≤D≤1.05D 0 At this time, the flatness is better, being able to be within 0.32 mm, and the welding defect rate is further reduced to within 0.30%, achieving a better technical effect.

[0097] In summary, when 0.9D 0 ≤D≤1.1D 0 the flatness of the core 10 can achieve the technical effects of the present invention, significantly reducing wrinkles, having a higher flatness of the core, ultimately having a higher welding quality of the current collector 20, and significantly improving the reliability of the battery.

[0098] Combined with Figure 6 an explanation of obtaining the flatness of the flat surface 11 is given. As Figure 6 shown, in the experiment, a 3D profiler is used to measure the flatness of the flat surface 11 of the core 10. Select the plane to be measured, and the machine identifies the highest point and the lowest point in the selected area, automatically calculating the difference between the high and low points, which is the flatness.

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

[0100] F = H1 - H2;

[0101] where 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

[0102] Exemplarily, Figure 6 In the figure, the shaded part is the eight measured welding areas 111. 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.

[0103] 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, and 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, and the inner diameter of the welding area 111 is R2, where R3 = R4 - W and R2 = R1 + W. In this case, Figure 6 the outer and inner peripheries of the sector of the welding area 111 and Figure 8 the R3 and R4 in Figure 3 and Figure 4 are coincident. 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 collector 20. Specifically, referring to

[0104] Taking the outermost positive electrode sheet 13 as an example, the outermost positive electrode sheet 13 is flanged and overlaps the fifth positive electrode sheet 13 from the inside. From the fourth layer inward, the visible multi-layer flanged positive electrode sheets 13 are formed. And at this position, due to the setting of the groove 112, the flat area after pressing is beneficial to subsequent welding. At the same time, taking the central hole as the boundary, the edge of the positive electrode sheet 13 after flanging that extends outward by a distance of W just abuts against the positioning pin. For the positive electrode sheet 13 in the region where the radius is less than R2 and greater than R1, its flanged edge abuts against the positioning pin. There is a situation of material accumulation in the radial direction, and this region is no longer suitable for welding with the current collector 20.

[0105] In an alternative embodiment, refer toFigure 6 The overall flatness of the welding area 111 is within 0.25 mm, and the flatness of each welding area 111 is within 0.2 mm. When welding with the current collector 20, the current collector 20 fits well with the flat surface 11. Each corresponding position of the welding area 111 and the current collector 20 is welded by a bonding wire 1111, and the effective welding rate of the bonding wire 1111 is close to 100%. At the same time, the bonding wire 1111 is welded in a straight spiral shape, with a simple shape and convenient welding. It should be noted that due to the high flatness of the flat surface obtained by the present invention, the selection of the bonding wire 1111 is not limited to the straight spiral welding, and any existing bonding wire can be used.

[0106] In an alternative embodiment, as Figure 6 shown, several bonding wires 1111 are radially and evenly distributed around the center of the bobbin 10. Through the above setting, the uniformity of welding between the flat surface 11 and the corresponding current collector 20 is improved. In this embodiment, as Figure 6 shown, the number of bonding wires 1111 and the number of grooves 112 are set to eight. In other embodiments, it can be understood that the present invention does not require all the welding areas 111 to be welded. 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, or 7, etc., which is not limited herein.

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

[0108] The dimensions of the bobbin 10 are R1 = 1.5 mm and R4 = 10.2 mm;

[0109] 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.

[0110] 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;

[0111] 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 R1 + w to R4 - W. So, the weldable area 111, from the inner circumference to the outer circumference of the bobbin 10, has a range of R2 = R1 + w to R3 = R4 - W, with a value of R2 = 3.39 mm to R3 = 8.31 mm. The value of M is 8; D 0 = πW / M = 0.742 mm.

[0112] Our selection range is 0.9D 0 ≤D≤1.1D 0 , in this embodiment, 0.668mm ≤ D ≤ 0.816mm;

[0113] In a preferred embodiment of this, we select D = D 0 , then D = 0.742mm.

[0114] In another embodiment, we select D = 1.02D 0 , then D = 0.757mm; in another embodiment, we select D = 0.96D 0 , then D = 0.712mm.

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

[0116] Dimensions of the core 10, 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 finally the measured value of W is 1.323mm.

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

[0119] Among them, the inner diameter R1 = 1.5mm and 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 ranges from the inner circumference to the outer circumference of the core 10 as 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, where 0.9D0 ≤ D ≤ 1.1D 0 , in this embodiment, 0.623mm ≤ D ≤ 0.761mm.

[0120] In a preferred embodiment of this, we select D = D 0 , then D = 0.692mm.

[0121] In another embodiment, we select D = 1.06D 0 , then D = 0.734mm; in another embodiment, we select D = 0.92D 0, then D = 0.637 mm.

[0122] 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 and the two flat surfaces 11 are arranged in one-to-one correspondence and 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.

[0123] 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.

[0124] In an optional embodiment, the electrical component can be an electronic device. For example, it can be listed 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 video camera, a digital camera, an e-book, an electronic dictionary, a music player, a radio, a headphone, 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, 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.

[0125] 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 an object through the shaft 434. A trigger switch 432 operated by a user is provided on the electric screwdriver 431.

[0126] In the lower frame of the handle of the electric screwdriver 431, a battery pack 430 (the battery pack 430 can be composed of multiple 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 components provided on each of them. As will be 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.

[0127] The battery pack 430 is, for example, freely detachable from and attachable to the electric screwdriver 431. The battery pack 430 may also be built into the electric screwdriver 431. The battery pack 430 is mounted on the charging device during charging. It should be noted that when the battery pack 430 is mounted 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.

[0128] 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.

[0129] In an alternative embodiment, the electrical component may be an electric vehicle. Examples of electric vehicles include railway vehicles, golf carts, electric carts, electric cars (including hybrid vehicles), etc., which are used as a driving power source or an auxiliary power source for them. Examples of the power storage device include a power storage power source for buildings such as houses or for power generation equipment.

[0130] Refer to Figure 10 An example of applying the present invention to a power storage system for an electric vehicle will be described. Figure 10 Briefly shows an example of the structure of a hybrid vehicle adopting a series hybrid system to which the present invention is applied. The 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 using an electric power driving force conversion device.

[0131] 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.

[0132] The hybrid vehicle 600 travels using the electric drive force conversion device 603 as a power source. An example of the electric drive force conversion device 603 is a motor. The electric drive force conversion device 603 operates using the power from the battery 608, and the rotational force of the electric drive 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 DC-AC or inverse conversion (AC-DC conversion) at necessary positions, the electric drive force conversion device 603 can be applied to an AC motor or a DC motor. The various sensors 610 control the engine speed or the opening degree of a throttle valve (throttle opening) (not shown) via the vehicle control device 609. The 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 by this rotational force, the electric power generated by the generator 602 can be stored in the battery 608.

[0134] 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 drive force conversion device 603, and the regenerative electric power generated by the electric drive force conversion device 603 by this rotational force is stored in the battery 608.

[0135] The battery 608 can also receive power supply from an external power source of the hybrid vehicle 600 through the charging port 611 as an input port and store the received power.

[0136] 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 for displaying the battery remaining amount based on information related to the remaining amount of the battery.

[0137] It should be noted that the above has been described by taking a series hybrid vehicle that travels using the electric power generated by a generator driven by an engine or temporarily stores the electric power in a battery as an example. However, the present invention can also be effectively applied to a parallel hybrid vehicle that uses both the outputs of an engine and a motor as drive sources and appropriately switches to travel only by the engine, only by the motor, or 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.

[0138] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on 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 within 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 periphery to the outer periphery of the winding core on the flat surface (11), and the cross section of the grooves (112) is a rectangle, and the grooves (112) are generally a straight through rectangular parallelepiped from the inner periphery to the outer periphery; 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; 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.

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: 6≤n≤13。 5. 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.

6. The winding core according to claim 5, wherein the vertical area is selectively coated with ceramic slurry or insulating glue to increase physical rigidity.

7. The winding core according to any one of claims 1 to 6, 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.

8. Full-ear cylindrical battery, characterized in that: It comprises the winding core as claimed in claim 7 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).

9. An electrical device, characterized in that: It comprises the full-tab cylindrical battery as claimed in claim 8 and an electrical component, wherein the full-tab cylindrical battery is used to supply power to the electrical component.

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