Electrode plate for secondary battery and method for manufacturing the same, and secondary battery and method for manufacturing the same

Abstract

An electrode plate for a secondary battery comprises: a thin plate-shaped core formed of metal foil; and an active material layer formed on at least one surface of the core. A molten portion of the metal foil forming the core scatters, adheres, and solidifies at an end of the electrode plate for the secondary battery, extending from the thickness of the core toward the end surface of the active material layer.

Description

Technical Field

[0001] The present disclosure relates to an electrode plate for a secondary battery and a method for manufacturing the same, as well as a secondary battery and a method for manufacturing the same. Background Art

[0002] When manufacturing an electrode plate as a negative electrode plate or a positive electrode plate used in a secondary battery, the electrode plate is sometimes formed by cutting an electrode precursor having a long active material layer formed on a thin long core into a predetermined electrode size.

[0003] Patent document 1 describes the following: When laser cutting an electrode plate for a secondary battery, in order to prevent the core from protruding further outward than the active material layer at the cutting end, an electrode precursor having active material layers formed on both sides of a long core is cut by laser cutting so that at the end of the electrode plate, the end of the core is expanded into a triangular cross-section, and is located further inward than the end of the active material layer in terms of the surface direction of the electrode plate, or is flush with the end of the active material layer.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 043444 Summary of the Invention

[0007] If a secondary battery electrode plate is formed by cutting a long electrode precursor, the active material may be peeled off from the cut end of the active material layer and fall off.

[0008] As one embodiment of the present invention, an electrode plate for a secondary battery is an electrode plate for a secondary battery comprising a thin plate-shaped core formed of metal foil and an active material layer formed on at least one surface of the core, wherein the molten portion of the metal foil forming the core is scattered, attached and solidified at the end of the electrode plate for the secondary battery in a manner extending from the plate thickness range of the core to the end surface of the active material layer.

[0009] A secondary battery as one embodiment of the present disclosure includes the secondary battery electrode plate of the present disclosure.

[0010] As one embodiment of the present invention, a method for manufacturing an electrode plate for a secondary battery is disclosed. When an electrode precursor is formed into an electrode plate for a secondary battery or an intermediate of an electrode plate for a secondary battery by laser cutting, a molten portion generated by melting of a metal foil is scattered at the end of the electrode plate for the secondary battery in a manner that extends from the plate thickness range of the core toward the end face of the active material layer; the electrode precursor comprises: a thin plate-shaped base core formed of metal foil; and a base active material layer formed on at least one surface of the base core.

[0011] A method for producing a secondary battery as one embodiment of the present disclosure is performed using an electrode plate for a secondary battery produced by the method for producing an electrode plate for a secondary battery of the present disclosure.

[0012] According to an electrode plate for a secondary battery and a method for manufacturing the same, as well as a secondary battery and a method for manufacturing the same, which are one embodiment of the present disclosure, it is possible to prevent the active material layer from falling off from the cut end without expanding the end of the core into a triangular cross-section. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view of a secondary battery according to an example of the embodiment.

[0014] Figure 2 is in the composition Figure 1 A three-dimensional diagram showing the terminal end of an electrode body of a secondary battery with the terminal end unfolded.

[0015] Figure 3 It forms a structure Figure 2 Developed view of a portion of the negative electrode precursor of the negative electrode plate of the electrode assembly in the longitudinal direction.

[0016] Figure 4 yes Figure 3 AA cross-sectional view.

[0017] Figure 5 This is a cross-sectional view of the cut end side portion of the negative electrode plate.

[0018] Figure 6 This is a schematic diagram of a SEM image of a cut end surface of a negative electrode plate in one embodiment. DETAILED DESCRIPTION

[0019] To address the aforementioned issues, the inventors conducted in-depth research and discovered that, in a secondary battery electrode plate, a thin plate-shaped core formed of metal foil and an active material layer formed on at least one surface of the core is provided. Furthermore, the molten portion of the metal foil forming the core is dispersed and adhered at the end of the secondary battery electrode plate, extending from the thickness of the core toward the end surface of the active material layer. This prevents the active material layer from falling off the cut end, without expanding the end of the core into a triangular cross-section. This is described in detail below.

[0020] Below, an example embodiment of the present disclosure is described in detail. In the following description, specific shapes, materials, directions, and numerical values ​​are provided for ease of understanding and may be modified as appropriate depending on the application, purpose, specifications, and the like. Below, a non-aqueous electrolyte secondary battery is described in which a wound electrode assembly is housed in a rectangular metal outer casing.

[0021] (Structure of Secondary Battery)

[0022] First, use Figure 1 、 Figure 2 The configuration of the secondary battery 10 will be described. Figure 1 is a cross-sectional view of the secondary battery 10, Figure 2 It is a perspective view showing the winding end portion of the electrode body 20 constituting the secondary battery 10 in a developed manner.

[0023] The secondary battery 10 includes an outer case 12 serving as a housing and a wound electrode assembly 20 disposed within the outer case 12. A non-aqueous electrolyte, corresponding to a non-aqueous electrolyte, is contained within the outer case 12. The non-aqueous electrolyte, for example, contains a lithium salt and has lithium ion conductivity.

[0024] like Figure 2 As shown, the electrode body 20 is a flat structure wound with a winding axis O extending along the length of the secondary battery 10. The positive electrode plate 22 and the negative electrode plate 26 are wound with separators 30 and 31 interposed therebetween. For example, the electrode body 20 is wound by stacking the elongated positive electrode plate 22, the elongated separator 30, the elongated negative electrode plate 26, and the elongated separator 31, with the separator 31 positioned at the outermost periphery. The positive electrode plate 22 and the negative electrode plate 26 each correspond to an electrode plate for a secondary battery.

[0025] like Figure 1 As shown, the metal outer shell 12 is a box-shaped body with an opening at the top, and the secondary battery 10 is provided with a sealing plate 14 for sealing the opening. The outer shell 12 and the sealing plate 14 can be made of aluminum or an aluminum alloy. On the sealing plate 14, a positive terminal 15 is provided from one end in the longitudinal direction ( Figure 1 The negative terminal 16 protrudes from the other end in the length direction ( Figure 1 The positive terminal 15 and the negative terminal 16 are inserted into two through holes formed in the sealing plate 14 and fixed to the sealing plate 14 via a resin gasket. The winding axis of the electrode body 20 is aligned with the longitudinal direction of the sealing plate 14 ( Figure 1 Alternatively, an insulating sheet bent into a box shape may be provided on the inner side of the outer shell 12 to achieve insulation between the electrode body 20 and the outer shell 12.

[0026] (Positive plate)

[0027] The positive electrode plate 22 includes a positive electrode core 23 and positive electrode active material layers 24 formed on both sides of the positive electrode core 23 and containing a positive electrode active material. Figure 2In the figure, the positive electrode active material layer 24 is represented by the sand grain portion. The positive electrode core 23 is a thin plate-shaped core formed of a foil of a metal such as aluminum or an aluminum alloy that is stable within the potential range of the positive electrode. As the positive electrode active material, a lithium transition metal oxide that can intercalate and deintercalate lithium ions can be used. The positive electrode active material layer 24 preferably contains a binder and a conductive material in addition to the positive electrode active material. The positive electrode plate 22 includes: a main body 22a on which the positive electrode active material layer 24 is formed; and a positive electrode core exposed portion 22b on which the positive electrode active material layer is not formed and the positive electrode core 23 is exposed. The positive electrode core exposed portion 22b is formed at one end portion in the width direction of the positive electrode plate 22 before winding. The positive electrode plate 22 may also have a porous protective layer having a thickness less than that of the positive electrode active material layer 24 formed in the region adjacent to the positive electrode active material layer 24 in the positive electrode core exposed portion 22b.

[0028] Examples of positive electrode active materials include lithium transition metal oxides containing transition metal elements such as Co, Mn, and Ni. Examples of lithium transition metal oxides include Li x CoO2、Li x NiO2、Li x MnO2、Li x Co y Ni 1-y O2、Li x Co y M 1-y O z 、Li x Ni 1- y M y O z 、Li x Mn2O4、Li x Mn 2-y MyO4, LiMPO4, Li2MPO4F (M: at least one of Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, B, 0<x≤1.2, 0<y≤0.9, 2.0≤z≤2.3). These can be used alone or in combination. From the perspective of achieving a high capacity of the secondary battery 10, the positive electrode active material preferably contains Li x NiO2、Li x Co y Ni 1-y O2、Li x Ni 1-y M y O zLithium nickel composite oxides such as (M: at least one of Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B, 0<x≤1.2, 0<y≤0.9, 2.0≤z≤2.3).

[0029] The conductive material used in the positive electrode active material layer 24 includes, for example, carbon black (CB), acetylene black (AB), Ketjen black, carbon nanotubes (CNT), graphite and other carbon particles. These can be used alone or in combination of two or more. As the conductive material used in the positive electrode active material layer 24, carbon black is preferably used.

[0030] The binding material used in the positive electrode active material layer 24 can be, for example, fluorine-based resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide resins, acrylic resins, and polyolefin resins. These can be used alone or in combination of two or more. As the binding material used in the positive electrode active material layer 24, polyvinylidene fluoride is preferably used.

[0031] The positive electrode plate 22 can be manufactured by coating a positive electrode active material layer slurry containing a positive electrode active material, a binder, and a dispersion medium on the positive electrode core 23, drying the coating and removing the dispersion medium, and then compressing to form the positive electrode active material layer 24 on both sides of the positive electrode core 23. In this case, the positive electrode plate can also be manufactured by coating the positive electrode active material layer slurry and the protective layer slurry on the positive electrode core 23, drying the coating and removing the dispersion medium, and then compressing to form the positive electrode active material layer 24 and the protective layer on both sides of the positive electrode core 23.

[0032] (Negative plate)

[0033] The negative electrode plate 26 includes a negative electrode core 27 and negative electrode active material layers 28 formed on both surfaces of the negative electrode core 27 and containing a negative electrode active material. Figure 2 In the figure, the negative electrode active material layer 28 is represented by the sand grain portion. The negative electrode core 27 is a thin plate-shaped core formed of a foil of a metal such as copper or copper alloy that is stable within the potential range of the negative electrode. Carbon materials, silicon compounds, etc. that can intercalate and deintercalate lithium ions can be used as the negative electrode active material. The negative electrode active material layer 28 preferably contains a binding material in addition to the negative electrode active material. The negative electrode plate 26 includes: a main body 26a on which the negative electrode active material layer 28 is formed; and a negative electrode core exposed portion 26b on which the negative electrode core 27 is exposed without forming the negative electrode active material layer. The negative electrode core exposed portion 26b is formed at one end portion in the width direction of the negative electrode plate 26 before winding.

[0034] The negative electrode active material is not particularly limited as long as it can reversibly store and release lithium ions. Examples include carbon materials such as natural graphite and artificial graphite; metals alloyed with lithium, such as silicon (Si) and tin (Sn); and alloys and composite oxides containing metal elements such as Si and Sn. Carbon materials are preferred, with natural graphite being more preferred. These negative electrode active materials may be used alone or in combination of two or more.

[0035] The negative electrode plate 26 can be manufactured by coating a negative electrode active material layer slurry containing a negative electrode active material, a binder, and a dispersion medium on the negative electrode core 27, drying the coating to remove the dispersion medium, and then compressing the coating to form a negative electrode active material layer 28 on both sides of the negative electrode core 27.

[0036] Especially in this case, as described later Figure 5 As shown, the negative electrode plate 26 is scattered, attached, and solidified in such a manner that the melted portion of the metal foil forming the negative electrode core 27 spreads from the plate thickness range t of the negative electrode core 27 to the end surface of the negative electrode active material layer 28 at the end of the negative electrode plate 26. Figure 5 In the figure, the hatched portion indicates the solidified melted portion of the metal foil of the negative electrode core 27. This prevents the negative electrode active material layer 28 from falling off from the cut end 28a, as described later, without expanding the end of the negative electrode core 27 into a triangular cross-section.

[0037] like Figure 1 As shown, in the electrode body 20, in the winding axis direction ( Figure 1 one end ( Figure 1 The exposed portion 22b of the wound positive electrode core is arranged at the other end portion ( Figure 1 A wound negative electrode core exposed portion 26b is provided at the right end portion of the negative electrode core.

[0038] (Separator)

[0039] Separator 30 is wound between positive electrode plate 22 and negative electrode plate 26 to electrically isolate positive electrode plate 22 from negative electrode plate 26. Separator 31 disposed on the outermost periphery prevents short circuit between negative electrode plate 26, the outermost electrode, and external components.

[0040] A porous sheet having ion permeability and insulation properties is used in each separator 30, 31. Specific examples of porous sheets include microporous films, woven fabrics, non-woven fabrics, and the like. Preferred materials for the separators 30, 31 include olefin resins such as polyethylene and polypropylene, and cellulose. The separators 30, 31 may be a laminate having a cellulose fiber layer and a thermoplastic resin fiber layer such as an olefin resin. In addition, each separator 30, 31 may be a multilayer separator comprising a polyethylene layer and a polypropylene layer, or a separator having an aromatic polyamide resin, ceramic, or the like coated on the surface of the separator 30, 31. For example, each separator 30, 31 may be made into a three-layer separator of polyethylene layer / polypropylene layer / polyethylene layer.

[0041] In addition, in the electrode body 20, the end portion of the separator 31 disposed on the outermost periphery on the winding end side is attached to one side surface in the thickness direction of the electrode body 20, and an insulating tape 60 ( Figure 1 ).

[0042] Furthermore, a positive electrode current collector 47 is electrically connected to the exposed portion 22b of the wound positive electrode core. Thus, the positive electrode current collector 47 is electrically connected to the positive electrode plate 22. The positive electrode current collector 47 is arranged on the opposite side of the electrode body 20 in the thickness direction ( Figure 1 The positive electrode supporting member 48 (on the front side of the paper) sandwiches the exposed positive electrode core portion 22b and is integrally connected. The positive electrode current collector 47 is electrically connected to the lower end of the positive electrode terminal 15, which vertically penetrates the first insulating member 61 disposed on the inner surface of the sealing plate 14.

[0043] The negative electrode current collector 50 is electrically connected to the exposed portion 26b of the wound negative electrode core. Thus, the negative electrode current collector 50 is electrically connected to the negative electrode plate 26. The negative electrode current collector 50 is arranged on the opposite side of the electrode body 20 in the thickness direction ( Figure 1 The negative electrode current collector 50 is electrically connected to the lower end of the negative electrode terminal 16, which vertically penetrates the second insulating member 62 disposed on the inner surface of the sealing plate 14.

[0044] The outer shell 12 has an opening sealed by welding a sealing plate 14 to the opening end.

[0045] (Negative Electrode Plate and Secondary Battery Manufacturing Method)

[0046] Next, use Figures 3 to 6 , focusing on the manufacturing method of the secondary battery 10, especially the negative electrode plate 26 ( Figure 2 、 Figure 5 ) is described in detail. Figure 3It is a development view of a portion in the longitudinal direction of a negative electrode precursor 32 that forms the negative electrode plate 26 . Figure 4 yes Figure 3 AA cross-sectional view. The manufacturing method of the negative electrode plate 26 of this embodiment is a method of manufacturing two or more negative electrode plates 26 at the same time. First, a precursor manufacturing step is performed to manufacture a negative electrode plate 26 having a width d ( Figure 2 、 Figure 3 ) together with the width W( Figure 3 ) of the negative electrode precursor 32 ( Figure 3 、 Figure 4 The negative electrode precursor 32 is a long plate having a base negative electrode active material layer 34 formed on both sides of a long base negative electrode core 33, and is equivalent to an electrode precursor. Figure 3 、 Figure 4 In the figure, the base negative electrode active material layer 34 is represented by the sand grain portion. The base negative electrode active material layer 34 is formed by preparing a negative electrode active material layer slurry containing a negative electrode active material, a binder, and a dispersion medium, applying the slurry to both sides of the base negative electrode core 33, and drying the coating to remove the dispersion medium. At this time, on both sides of the negative electrode precursor 32, in the width direction ( Figure 3 Up and down direction, Figure 4 The left and right directions) are formed at both ends along the length direction ( Figure 3 Left and right direction, Figure 4 The exposed core portion 35 extends (in the front-to-back direction of the paper). The exposed core portion 35 is the portion where the base negative electrode core 33 is exposed without forming an active material layer on the surface. The exposed core portion 35 is formed by not coating the base negative electrode core 33 with a negative electrode active material layer slurry. The exposed core portion 35 can also be formed by forming a negative electrode active material layer entirely on both sides of the base negative electrode core 33 and then peeling off a portion of the negative electrode active material layer. The base negative electrode core 33 is equivalent to the base core, and the base negative electrode active material layer 34 is equivalent to the base active material layer.

[0047] Next, the negative electrode plate 26 is manufactured by compressing the negative electrode precursor 32 using a compression roller or the like in a compression process so as to compress the base negative electrode active material layer 34. Next, the negative electrode plate is manufactured by cutting the negative electrode precursor 32 in the center ( Figure 3 、 Figure 4 The negative electrode precursor 32 is cut along the dot-dash line C) and cut so that the length in the longitudinal direction becomes a predetermined length. When the negative electrode precursor 32 is cut in the center in the width direction, the laser device is used to irradiate the center in the width direction of the negative electrode precursor 32 with a laser 70 ( Figure 4 ), while making the processing head of the laser device and the negative electrode precursor 32 positioned in the longitudinal direction of the negative electrode precursor 32 ( Figure 4 For example, the negative electrode precursor 32 is moved in the front-to-back direction of the paper. Figure 4 At this time, the position of the processing head of the laser device can be fixed, but the processing head can also be moved in the direction opposite to the moving direction of the negative electrode precursor 32.

[0048] The laser device, for example, includes a laser oscillator and a processing head with a built-in galvanometer scanner. The laser oscillator can oscillate continuously and output laser light in a continuous oscillation mode. As a laser oscillator, for example, a fiber laser can be used, and as a laser oscillator, a YAG laser, a CO2 laser, an Ar laser, etc. can be used. In the laser device, a collimator that converts the laser light output from the laser oscillator into a parallel beam is provided between the laser oscillator and the galvanometer scanner. The galvanometer scanner guides the laser light that passes through the collimator to optical elements such as a reflector, a diffraction grating, an X-axis reflector, and a Y-axis reflector in sequence. The X-axis is along the length direction of the negative electrode precursor 32. The Y-axis is along the width direction of the negative electrode precursor 32. The laser light reflected by the X-axis reflector and the Y-axis reflector is irradiated onto the negative electrode precursor 32 through an Fθ lens and a protective glass. The laser light can be scanned by moving the X-axis reflector and the Y-axis reflector, and the position of the irradiation spot can be changed in a two-dimensional plane.

[0049] Preferably, a continuous wave laser (CW laser) is used for laser irradiation using a laser device, the laser output, i.e., the laser output power, is set to 1200W to 1550W, and the laser scanning speed, i.e., the cutting speed, of the negative electrode precursor 32 is set to 3000mm / second to 8000mm / second. More preferably, a continuous wave laser is used for laser irradiation, and when the laser scanning speed of the negative electrode precursor 32 is set to 5000mm / second to 8000mm / second, the laser output power is set to 1200W to 1400W, and when the laser scanning speed of the negative electrode precursor 32 is set to 3000mm / second to less than 5000mm / second, the laser output power is set to 1300W to 1550W. Therefore, in the manufacturing method of the negative electrode plate 26, when the negative electrode precursor 32 is cut by laser to form the negative electrode plate 26, the molten portion generated by the melting of the metal foil is scattered at the cut side end of the negative electrode plate 26 in a manner that expands from the plate thickness range of the negative electrode core 27 to the end face of the cut end 28a of the negative electrode active material layer 28.

[0050] In this example, as described above, the width W ( Figure 3 ) has a width d ( Figure 2 、 Figure 3 ) added together, so as mentioned above, if the laser is irradiated on the center of the width direction of the negative electrode precursor 32 and the negative electrode precursor 32 is cut along the length direction, two long strips of negative electrode intermediates with a width d corresponding to the negative electrode plate 26 can be obtained.

[0051] Since the negative electrode precursor 32 is linearly cut by the laser at its center in the width direction, the laser device can also be configured to scan the laser in one dimension. For example, the Y-axis mirror can be omitted or immobilized in the laser device.

[0052] In the cutting step, the two negative electrode intermediates obtained as described above are cut at predetermined locations in the longitudinal direction to form a plurality of negative electrode plates 26 of predetermined sizes. A continuous wave laser can be used for cutting at predetermined locations in the longitudinal direction, but conventional cutting methods such as a cutter can also be used. It should be noted that the longitudinal length of the negative electrode precursor 32 can also be made consistent with the length of the negative electrode plate 26. In this case, in the cutting step, the negative electrode precursor 32 is not cut at predetermined locations in the longitudinal direction, and the negative electrode precursor 32 is cut at the center in the width direction to form two negative electrode plates 26.

[0053] Figure 5 2 is a cross-sectional view of the cut end 28a side portion of the negative electrode plate 26. Figure 5 In FIG. 2 , the sand grain portion represents the negative electrode active material layer 28, and the hatched portion represents the solidified portion of the metal foil forming the negative electrode core 27 due to the melt formed by the laser. Figure 5 As shown, in the negative electrode plate 26, the melted portion of the metal foil forming the negative electrode core 27 is scattered, attached, and solidified at the end portion of the negative electrode plate 26 on the side of the cut end 28a formed by the laser, in a manner that spreads from the plate thickness range t of the negative electrode core 27 to the end surface of the negative electrode active material layer 28. For example, a continuous oscillation laser is used, the laser output power is set to 1200W to 1550W, and the laser scanning speed for the negative electrode precursor 32, that is, the cutting speed, is set to 3000mm / second to 8000mm / second. By appropriately adjusting the combination of the laser output power and the scanning speed, a Figure 5 In addition, when a continuous oscillation laser is used, the scanning speed of the laser on the negative electrode precursor 32 is set to 5000 mm / s or more and 8000 mm / s or less, the laser output power is set to 1200W to 1400W, the scanning speed of the laser on the negative electrode precursor 32 is set to 3000 mm / s or more and less than 5000 mm / s, and the laser output power is set to 1300W to 1550W, a cross-sectional state can also be obtained. Figure 5 The cross-sectional state shown.

[0054] like Figure 5 As shown, the solidified portion of the molten portion is at least in the length direction ( Figure 5 A portion of the negative electrode active material layer 28 (in the front-to-back direction of the paper) extends outward in the plate thickness direction and is connected to the cut end 28a side end portion of the negative electrode active material layer 28. Figure 5The cross section of the negative electrode plate 26 at one position in the longitudinal direction is shown in FIG. 1 , but there are also cross sections at other positions in the longitudinal direction. Figure 5 Similar trends.

[0055] Figure 6 FIG. 1 is a schematic diagram of a SEM image of a cut end surface of the negative electrode plate 26 in an example of an embodiment. Figure 6 In the figure, the blackened portion indicates the portion where the metal foil, such as copper foil, is scattered and melted due to the heat of the laser during cutting. Such a cut end face can be obtained, for example, by using a continuous oscillation laser with a laser output power of 1200W to 1550W and a laser scanning speed of 3000mm / s to 8000mm / s on the negative electrode precursor 32, and by appropriately adjusting the combination of laser output power and scanning speed. Figure 6 As shown, at the cut end face of the negative electrode plate 26, the melted portion of the metal foil splashes onto the outside of the plate thickness range t of the negative electrode core 27, that is, onto the end faces of the cut ends 28a of the negative electrode active material layers 28 on both sides, where it fuses and solidifies. This forms a metal coating 29 in which the solidified portion extends to the outside of the plate thickness range t of the negative electrode core 27. The metal coating 29 is bonded to the end faces of the cut ends 28a of the two negative electrode active material layers 28 on both sides in the plate thickness direction.

[0056] In the manufacturing method of the secondary battery 10, the positive electrode plate 22 is also produced. Similar to the negative electrode plate 26, the positive electrode plate 22 is produced by compressing a positive electrode precursor comprising a thin plate-shaped base positive electrode core formed of metal foil and base positive electrode active material layers formed on both surfaces of the base positive electrode core. After the base positive electrode active material layers are compressed, the precursor is cut at the center of the width using a laser to form two intermediate positive electrode plates, or two positive electrode plates 22. By cutting the two intermediate positive electrode plates at predetermined locations in the longitudinal direction, a plurality of positive electrode plates 22 of predetermined dimensions are formed.

[0057] In the method for manufacturing the secondary battery 10, after manufacturing the positive electrode plate 22, the negative electrode plate 26, and the separators 30 and 31, the positive electrode plate 22, the negative electrode plate 26, and the separators 30 and 31 are stacked and wound to produce the electrode body 20. After the electrode body 20 is manufactured, the electrode body 20 and the non-aqueous electrolyte are placed in the outer shell 12, and the sealing plate 14 is welded to the open end of the outer shell 12 to produce the secondary battery 10. Thus, the secondary battery 10 is manufactured using the negative electrode plate 26 manufactured by the above-mentioned method for manufacturing the negative electrode plate 26.

[0058] (Effect)

[0059] According to the negative electrode plate 26 and its manufacturing method, as well as the secondary battery 10 and its manufacturing method, the solidified portion of the melted portion of the metal foil of the negative electrode core 27 extends outward in the plate thickness direction at least partially at the cut end of the negative electrode core 27, forming a metal coating 29 that is bonded to the cut end of the negative electrode active material layer 28. This prevents the negative electrode active material layer 28 from falling off the cut end 28a. Furthermore, according to the embodiment, there is no need to expand the end of the negative electrode core 27 into a triangular cross-section, as in the configuration described in Patent Document 1.

[0060] It should be noted that when the positive electrode precursor is cut in the center of its width using a laser, similar to the method for manufacturing the negative electrode plate 26 described above, the molten portion created by melting the metal foil of the positive electrode core 23 can be dispersed at the cut end of the positive electrode plate 22, extending from the thickness of the positive electrode core 23 toward the end surface of the positive electrode active material layer 24. Furthermore, this method for manufacturing the positive electrode plate 22 can also produce a positive electrode plate 22 in which the molten portion of the metal foil disperses, adheres, and solidifies at the end of the positive electrode plate 22, extending from the thickness of the positive electrode core 23 toward the end surface of the positive electrode active material layer 24. In this case, the solidified portion of the molten portion of the metal foil of the positive electrode core 23 extends outward in the thickness direction of at least a portion of the cut end of the positive electrode core 23, forming a metal coating bonded to the cut end of the positive electrode active material layer 24. This prevents the positive electrode active material layer 24 from falling off the cut end.

[0061] In the above embodiment, the negative electrode plate 26 is described as having a negative electrode active material layer 28 formed on both sides of the negative electrode core 27, and the positive electrode plate 22 is described as having a positive electrode active material layer 24 formed on both sides of the positive electrode core 23. However, the negative electrode plates and positive electrode plates manufactured by the manufacturing method disclosed in the present invention are not limited to this structure. It can also be a structure in which the negative electrode plate has a negative electrode active material layer formed only on a single side of the negative electrode core, and the positive electrode plate has a positive electrode active material layer formed only on a single side of the positive electrode core.

[0062] Description of Reference Numerals

[0063] 10 Secondary Batteries

[0064] 12 outer shell

[0065] 14 Sealing plate

[0066] 15 Positive terminal

[0067] 16 Negative terminal

[0068] 20 Electrode body

[0069] 22 positive plate

[0070] 22a Main body

[0071] 22b Positive electrode core exposed part

[0072] 23. Positive electrode core

[0073] 24 Positive electrode active material layer

[0074] 26 negative plate

[0075] 26a Main body

[0076] 26b Negative electrode core exposed part

[0077] 27 Negative electrode core

[0078] 28 Negative electrode active material layer

[0079] 28a Cutting end

[0080] 29 Metal coating

[0081] 30, 31 separators

[0082] 32 Anode Precursor

[0083] 33 base negative electrode core

[0084] 34 Base negative electrode active material layer

[0085] 35 Core exposed part

[0086] 47 positive electrode collector

[0087] 48. Positive electrode support member

[0088] 50 negative electrode collector

[0089] 58 negative electrode support member

[0090] 60 Insulation Tape

[0091] 61 First insulating member

[0092] 62 The second insulating member.

Claims

1. An electrode plate for a secondary battery, comprising: a thin plate-shaped core formed of a metal foil; and an active material layer formed on at least one surface of the core. The molten portion of the metal foil forming the core body is scattered, attached, and solidified at the end of the secondary battery electrode plate in a manner that spreads from the plate thickness range of the core body to the end surface of the active material layer. The molten portion scatters onto the end surface of the active material layer and is welded and solidified, thereby forming a metal coating whose solidified portion extends to the outside of the plate thickness range of the core body. The end face is an end face of a cutting end, and the end of the core body does not expand into a triangular cross-section. 2 . A secondary battery comprising the electrode plate for a secondary battery according to claim 1 .

3. A method for manufacturing an electrode plate for a secondary battery, wherein the method for manufacturing an electrode plate for a secondary battery according to claim 1 comprises: When the electrode precursor is cut by laser to form the electrode plate for the secondary battery or the intermediate of the electrode plate for the secondary battery, a continuous oscillation laser is used, the laser output power is 1200W to 1550W, and the laser scan speed of the electrode precursor is 3000mm / second to 8000mm / second to cut, so that the molten portion generated by the melting of the metal foil is scattered at the end of the electrode plate for the secondary battery in a manner that spreads from the plate thickness range of the core body to the end face of the active material layer. The electrode precursor includes: a thin plate-shaped base core formed of a metal foil; and a base active material layer formed on at least one surface of the base core.

4. The method for manufacturing an electrode plate for a secondary battery according to claim 3, wherein: The laser output power when the electrode precursor is cut by laser is 1200W to 1400W, and the cutting speed of the electrode precursor is 3000mm / second to 8000mm / second. 5 . A method for producing a secondary battery, comprising: using the electrode plate for a secondary battery produced by the method for producing an electrode plate for a secondary battery according to claim 3 .

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