Pole piece assembly and battery

Abstract

The utility model discloses a pole piece assembly and a battery, the pole piece assembly comprises a pole piece, the pole piece comprises an active material layer and a foil material, the foil material comprises an empty foil area and a coating area, the active material layer is connected with the coating area, and the empty foil area comprises a first surface and a second surface which are opposite to each other; the metal piece is welded and connected to the first surface; and the tab is welded and connected to the second surface. According to the pole piece assembly disclosed by the utility model, the tensile strength between the foil and the pole lug is relatively high.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially is related to a pole piece subassembly and battery. BACKGROUND

[0002] In the related art, after the pole piece is manufactured, the pole piece and the tab need to be welded to realize the conduction of the pole piece and the outside. Specifically, the pole piece includes a foil and an active material layer. After the active material layer is coated on the foil, the foil area is cleaned by laser on the pole piece, and then the tab is welded on the foil area.

[0003] Further, when the tab is welded on the foil, the welding power cannot be too large because the thickness of the foil is thin, otherwise the foil will be broken. However, if the welding power is too small, the welding effect will be poor and the tensile strength between the tab and the foil will be low. SUMMARY

[0004] The utility model discloses at least one of the technical problems in the prior art. To this end, the utility model provides a pole piece subassembly, which can have high tensile strength between the foil and the tab.

[0005] The utility model also provides a battery.

[0006] According to the pole piece subassembly of the first aspect of the utility model, comprising:

[0007] The pole piece includes an active material layer and a foil. The foil includes a foil area and a coating area. The active material layer is connected to the coating area. The foil area includes opposite first and second faces.

[0008] The metal piece is welded to the first face.

[0009] The tab is welded to the second face.

[0010] According to the pole piece subassembly of the utility model, the following advantages are achieved: the metal piece is arranged on the first face of the foil area, and the tab is arranged on the second face of the foil area. When the tab and the second face are welded, high welding power can be used. In the prior art, the foil is thin, so high welding power can cause the foil to break. However, in this application, when the tab and the foil are welded with high welding power, the metal piece can participate in the welding process of the foil and the tab. The metal piece can penetrate and fuse between the tab and the foil, which can effectively reduce the probability of foil breakage and improve the welding quality. In this way, the welding quality between the foil and the tab is good, and the foil and the tab can have high tensile strength.

[0011] According to the tab assembly of some embodiments of the present application, the first welding mark and the second welding mark are both provided with a plurality of first sub-welding marks and a plurality of second sub-welding marks, the plurality of first sub-welding marks are arrayed, and the plurality of second sub-welding marks are arrayed.

[0012] According to the tab assembly of some embodiments of the present application, the first welding mark and the second welding mark are both provided with a plurality of first sub-welding marks and a plurality of second sub-welding marks, the plurality of first sub-welding marks are arrayed, and the plurality of second sub-welding marks are arrayed.

[0013] According to the tab assembly of some embodiments of the present application, the tab assembly further comprises a first adhesive layer, the tab comprises a positive tab, the tab lug comprises a positive tab lug, the first adhesive layer covers the positive tab lug and the positive tab, the thickness of the metal piece is A, the thickness of the positive tab is H, the thickness of the positive tab lug is H1, the thickness of the foil is H2, the thickness of the first adhesive layer is H3, and 7um≤A≤H-H1-H2-H3.

[0014] According to the tab assembly of some embodiments of the present application, the tab assembly further comprises a second adhesive layer, the tab comprises a negative tab, the tab lug comprises a negative tab lug, the second adhesive layer covers the negative tab lug and the negative tab, the thickness of the metal piece is B, the thickness of the negative tab is K, the thickness of the negative tab lug is K1, the thickness of the foil is K2, the thickness of the second adhesive layer is K3, and 4um≤B≤K-K1-K2-K3.

[0015] According to the tab assembly of some embodiments of the present application, the tab lug and the second surface have a first welding mark, along the length direction of the tab, the size of the empty foil area is L1, the size of the metal piece is L2, and the size of the first welding mark is L3, and L1≥L2≥L3.

[0016] According to the tab assembly of some embodiments of the present application, the tab lug and the second surface have a first welding mark, along the width direction of the tab, the size of the empty foil area is W1, the size of the metal piece is W2, and the size of the first welding mark is W3, and W1≥W2≥W3.

[0017] According to the tab assembly of some embodiments of the present application, the metal piece and the first surface have a second welding mark, along the length direction of the tab, the size of the empty foil area is L4, the size of the metal piece is L5, and the size of the second welding mark is L6, and L4≥L5≥L6.

[0018] According to the pole piece assembly of some embodiments of the utility model, the metal piece and the first face have a second welding mark, along the width direction of the pole piece, the size of the empty foil area is W4, the size of the metal piece is W5, the size of the second welding mark is W6, W4 >= W5 >= W6.

[0019] The battery according to the second aspect of the utility model comprises the pole piece assembly according to any one of the first aspect of the utility model.

[0020] The battery according to the utility model has at least the following beneficial effects: by arranging the metal piece on the first face of the empty foil area and the tab on the second face of the empty foil area, when the tab and the second face are welded, the welding can be carried out by high welding power, in the prior art, because the thickness of the foil material is thin, so high welding power can cause the foil material to be welded and broken, but in the present application, when the tab and the foil material are welded by high welding power, the metal piece can participate in the welding process of the tab and the foil material, and the metal piece can be penetrated and fused between the tab and the foil material, which can effectively reduce the probability of the foil material being welded and broken, thereby improving the welding quality, in this way, the welding quality between the tab and the foil material can be good, and the tab and the foil material can have high tensile strength.

[0021] Additional aspects and advantages of the utility model will be given in part in the following description, part will become obvious from the following description, or be understood through the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0022] The utility model will be further described below in combination with the drawings and embodiments, wherein:

[0023] Figure 1 It is the schematic view of the pole piece assembly of the first embodiment of the utility model;

[0024] Figure 2 It is the schematic view of the pole piece assembly of the second embodiment of the utility model;

[0025] Figure 3 It is the schematic view of the pole piece assembly of the third embodiment of the utility model;

[0026] Figure 4 It is the schematic view of the first welding mark in the pole piece assembly of some embodiments of the utility model.

[0027] REFERENCE SIGNS:

[0028] The pole piece assembly 10, the pole piece 100, the active material layer 110, the foil 120, the empty foil area 121, the first face 122, the second face 123, the coating area 124, the metal piece 200, the pole lug 300, the first welding mark 400, the first sub welding mark 410, the second sub welding mark 420, the first adhesive layer 500. DETAILED DESCRIPTION

[0029] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application.

[0030] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation on the present application.

[0031] In the description of the present application, the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0032] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application according to the specific content of the technical scheme.

[0033] In the description of the present application, the description of the reference terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0034] The battery can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the present application is not limited thereto.

[0035] The battery generally includes a cell. The cell includes a positive electrode, a negative electrode, and a separator. During the charging and discharging of the battery, active ions (e.g., lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, and can prevent the positive and negative electrodes from short-circuiting while allowing the active ions to pass through.

[0036] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0037] As an example, the positive electrode current collector has two opposite surfaces in the thickness direction thereof, and the positive electrode active material is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0038] As an example, the positive electrode current collector can be a metal foil. For example, as the metal foil, aluminum with silver plating on the surface, stainless steel with silver plating on the surface, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, etc. can be used. A composite current collector can include a polymer material base layer and a metal layer.

[0039] As an example, the positive electrode active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include, but are not limited to, at least one of lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (which can also be referred to as NCM333), LiNi0.5Co0.2Mn0.3O2 (which can also be referred to as NCM523), LiNi0.5Co0.25Mn0.25O2 (which can also be referred to as NCM211), LiNi0.6Co0.2Mn0.2O2 (which can also be referred to as NCM622), LiNi0.8Co0.1Mn0.1O2 (which can also be referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi0.85Co0.15Al0.05O2), and modified compounds thereof.

[0040] In some embodiments, the positive electrode can employ a foam metal. The foam metal can be a foam aluminum, a foam alloy, or the like. When the foam metal is used as the positive electrode, the surface of the foam metal can not be provided with the positive electrode active material, or of course can be provided with the positive electrode active material. As an example, the foam metal can also be filled or / and deposited with a lithium source material, a potassium metal, or a sodium metal, the lithium source material being a lithium metal and / or a lithium-rich material.

[0041] In some embodiments, the negative electrode can be a negative electrode sheet, which can include a negative electrode current collector.

[0042] As an example, the negative electrode current collector can employ a metal foil, a foam metal, or a composite current collector. For example, as the metal foil, silver surface-treated stainless steel, stainless steel, copper, nickel, a carbon electrode, nickel, or titanium, or the like can be employed. The foam metal can be a foam nickel, a foam copper, a foam alloy, or the like.

[0043] As an example, the negative electrode sheet can include the negative electrode current collector and the negative electrode active material provided on at least one surface of the negative electrode current collector.

[0044] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode active material is provided on either one or both of the two surfaces of the negative electrode current collector.

[0045] As an example, the negative electrode active material can employ a negative electrode active material for a battery known in the art. As an example, the negative electrode active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, a silicon oxide compound, a silicon-carbon composite, a silicon-nitrogen composite, and a silicon alloy. The tin-based material can be selected from at least one of elemental tin, a tin oxide compound, and a tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as a negative electrode active material for a battery can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0046] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0047] In some embodiments, the battery further includes a separator disposed between the positive electrode and the negative electrode.

[0048] In some embodiments, the separator is a separator film. The separator film can be of various types, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0049] As an example, the material of the separator film can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film can be a single layer film or a multi-layer composite film. When the separator film is a multi-layer composite film, the materials of the respective layers can be the same or different. The separator can be a separate component located between the positive and negative electrodes, or can be attached to the surface of the positive and negative electrodes.

[0050] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode and the negative electrode, and functions to transport ions and separate the positive and negative electrodes.

[0051] In some embodiments, the battery further includes an electrolyte that functions to conduct ions between the positive and negative electrodes. The electrolyte can be in a liquid state, a gel state, or a solid state. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0052] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro oxalate borate, lithium difluoro oxalate borate, lithium difluoro di-oxalate phosphate, and lithium tetrafluoro oxalate phosphate.

[0053] In some embodiments, the solvent can include at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, butyl sulfone, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be selected from ether solvents. The ether solvents can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0054] In some embodiments, the gel-state electrolyte includes a polymer as a skeleton network of the electrolyte, and an ionic liquid-lithium salt.

[0055] In some embodiments, the solid-state electrolyte includes a polymer solid-state electrolyte, an inorganic solid-state electrolyte, and a composite solid-state electrolyte.

[0056] As an example, the polymer solid-state electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single-ion polymer, a polyionic liquid-lithium salt, cellulose, or the like.

[0057] As an example, the inorganic solid-state electrolyte can include one or more of oxide solid electrolytes (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), sulfide solid electrolytes (crystalline lithium superionic conductor (lithium germanium phosphorus sulfide, argyrodite), amorphous sulfide), and halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0058] As an example, the composite solid-state electrolyte is formed by adding inorganic solid-state electrolyte fillers to a polymer solid-state electrolyte.

[0059] In some embodiments, the battery cell has a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound into the jelly-roll structure.

[0060] In some embodiments, the battery cell has a stacked structure.

[0061] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be provided, and the plurality of positive electrode sheets and the plurality of negative electrode sheets can be alternately stacked.

[0062] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet can be folded to form a plurality of folded segments that are stacked. One positive electrode sheet can be clamped between adjacent folded segments.

[0063] As an example, the positive electrode sheet and the negative electrode sheet can be folded to form a plurality of folded segments that are stacked.

[0064] As an example, the separators can be provided in plurality, each provided between any adjacent positive electrode sheet or negative electrode sheet.

[0065] As an example, the separators can be provided in plurality, each provided between any adjacent positive electrode sheet or negative electrode sheet.

[0066] In some embodiments, the shape of the battery cell can be cylindrical, flat, or polygonal, etc.

[0067] In some embodiments, the battery cell can be provided with tabs, which can conduct current out of the battery cell. The tabs can include positive tabs and negative tabs.

[0068] In some embodiments, the battery can include a housing. The housing can be used to enclose the battery cell and other components such as electrolyte. The housing can be a steel case, an aluminum case, a plastic case (e.g., polypropylene), a composite metal case (e.g., copper-aluminum composite case), or an aluminum-plastic film, etc.

[0069] As an example, the battery can be a cylindrical battery, a prismatic battery, a pouch battery, or other shapes of batteries, which can include but are not limited to a square battery, a blade battery, a polygonal battery, such as a hexagonal battery, etc.

[0070] The battery as referred to in the embodiments of the present application can mean a single physical module including one or more batteries to provide higher voltage and capacity.

[0071] In some embodiments, the battery can be a battery module, and when there are multiple batteries, the multiple batteries can be arranged and fixed to form a battery module.

[0072] In some embodiments, the battery can be a battery pack, which can include a box and batteries, and the batteries or battery modules can be contained in the box.

[0073] In some embodiments, the box can be part of the chassis structure of a vehicle. For example, part of the box can be at least part of the floor of the vehicle, or part of the box can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0074] The embodiments of the present application provide a power consuming device using the battery as a power source. The power consuming device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, etc. The electric toy can include a stationary or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0075] In the related art, after the pole piece is manufactured, the pole piece and the tab need to be welded to realize the conduction of the pole piece to the outside. Specifically, the pole piece includes a foil and an active material layer. After the active material layer is coated on the foil, the foil is cleaned by laser to form an empty foil area, and then the tab is welded on the empty foil area.

[0076] Further, when the tab is welded on the foil, the welding power cannot be too large because the thickness of the foil is thin, otherwise the foil will be welded to break. However, if the welding power is too small, the welding effect will be poor, and the tensile strength between the tab and the foil will be low. Therefore, the application provides a pole piece assembly.

[0077] Please refer to Figures 1 to 3 In some embodiments, the pole piece 100 assembly 10 includes a pole piece 100, a metal piece 200, and a tab 300. The pole piece 100 includes an active material layer 110 and a foil 120. The pole piece 100 can include a positive pole piece 100 and a negative pole piece 100. The positive pole piece 100 includes a positive active material layer 110 and a positive foil 120, and the negative pole piece 100 includes a negative active material layer 110 and a negative foil 120. These belong to the prior art and will not be described further. The foil 120 includes an empty foil area 121 and a coated area 124. The active material layer 110 is connected to the coated area 124, and the active material layer 110 is not connected to the empty foil area 121. The empty foil area 121 includes a first face 122 and a second face 123 opposite to each other. The metal piece 200 is welded to the first face 122. The metal piece 200 can be a metal sheet, such as copper or aluminum. The tab 300 is welded to the second face 123. Specifically, by arranging the metal piece 200 on the first face 122 of the empty foil area 121 and the tab 300 on the second face 123 of the empty foil area 121, when the tab 300 and the second face 123 are welded, a high welding power can be used for welding. In the prior art, because the thickness of the foil 120 is thin, a high welding power will cause the foil 120 to be welded to break. However, in the present application, when the tab 300 and the foil 120 are welded by a high welding power, the metal piece 200 can participate in the welding process of the tab 300 and the foil 120. The metal piece 200 can penetrate and fuse between the tab 300 and the foil 120, which can effectively reduce the probability of the foil 120 being welded to break, thereby improving the welding quality. In this way, the welding quality between the foil 120 and the tab 300 can be good, and the foil 120 and the tab 300 can have a high tensile strength.

[0078] Further, the tensile strength between the foil 120 and the tab 300 mentioned above specifically refers to the strength that the tab 300 can resist from being separated from the foil 120 after the tab 300 and the foil 120 are welded. The tensile strength can be tested by a tensile testing tool, for example, by pulling the tab 300 and then testing the limit value of the tab 300 and the foil 120 being separated. In addition, it should be noted that the better the welding effect between the tab 300 and the foil 120, the higher the tensile strength between the tab 300 and the foil 120.

[0079] Further, it should be noted that in the present application, due to the high tensile strength between the foil 120 and the tab 300, the internal resistance at the welding position between the tab 300 and the foil 120 is small, which can effectively improve the energy density of the battery. The improvement of the energy density is because the stitch welding process is adopted, and the stitch welding process has a smaller welding area than the three-point welding process. In addition, this can also effectively improve the effective coating weight of the paste. Specifically, refer to Table 1 below.

[0080] Table 1

[0081]

[0082] Specifically, the K value generally refers to the voltage drop of the battery per unit time, which is an index for measuring the self-discharge rate of the lithium battery. That is, the smaller the internal resistance of the battery, the smaller the K value. As can be seen from the above embodiments 5 and 6, the design of the metal piece 200 can improve the tensile strength between the tab 300 and the foil 120 and improve the tensile strength of the tab 300. In addition, the design of the metal piece 200 can also effectively improve the energy density of the battery.

[0083] Further, please refer to Figure 4 , Figure 4 is a schematic view of the first welding 400. In some embodiments, the tab 300 has the first welding 400 with the second surface 123, and the first welding 400 includes a first sub-welding 410 and a second sub-welding 420. The projection of the first sub-welding 410 and the projection of the second sub-welding 420 do not overlap along the thickness direction of the tab 300. Specifically, the welding method of the tab 300 and the second surface 123 can be through a secondary welding method. That is, when the tab 300 and the second surface 123 are welded for the first time, a small power pre-welding is adopted to fix the tab 300 and the second surface 123. Then, when welded for the second time, a large power welding is adopted. After the secondary welding, the first welding 400 includes the first sub-welding 410 and the second sub-welding 420. In order to make the welding of the tab 300 and the foil 120 more firm, the first sub-welding 410 and the second sub-welding 420 can be staggered with each other, so as to increase the welding area and the molecular penetration degree of the welding point part.

[0084] Further, please refer to Figure 4 In some embodiments, the first sub-welding mark 410 and the second sub-welding mark 420 are both provided in plurality, and the plurality of first sub-welding marks 410 are arrayed, and the plurality of second sub-welding marks 420 are arrayed. Specifically, the arrayed distribution means that the plurality of first sub-welding marks 410 are distributed in a rectangular shape, or the plurality of first sub-welding marks 410 are distributed in a square shape, or the plurality of second sub-welding marks 420 are distributed in a rectangular shape, or the plurality of second sub-welding marks 420 are distributed in a square shape. After the plurality of first sub-welding marks 410 and the plurality of second sub-welding marks 420 are arrayed, on the one hand, this can facilitate the welding of the tab 300 and the foil 120 according to a fixed rule, thereby improving the welding efficiency. On the other hand, the edges of the first sub-welding mark 410 and the second sub-welding mark 420 can form a regular V-shaped pattern, thereby increasing the edge contact circumference of the welding spot and the foil 120, and improving the welding effect.

[0085] Further, the thickness value of the metal piece 200 when the pole piece 100 is a positive pole piece 100 is introduced below. In some embodiments, the pole piece 100 assembly 10 further comprises a first adhesive layer 500, which can refer to Figures 1 to 2 , Figure 1 and Figure 2 The pole piece 100 can also be referred to as a positive pole piece 100. The pole piece 100 comprises a positive pole piece 100, the tab 300 comprises a positive tab 300, the first adhesive layer 500 covers the positive tab 300 and the positive pole piece 100, the thickness of the metal piece 200 is A, the thickness of the positive pole piece 100 is H, the thickness of the positive tab 300 is H1, the thickness of the foil 120 is H2, the thickness of the first adhesive layer 500 is H3, and 7um≤A≤H-H1-H2-H3. Specifically, the thickness of the metal piece 200 can be 7um, 8um or 10um. It can be envisaged that the higher the thickness of the metal piece 200, the higher the welding power after the metal piece 200 and the foil 120 are bonded, thereby improving the welding effect. Conversely, when the thickness of the metal piece 200 is less than 7um, it can result in poor welding effect between the foil 120 and the tab 300.

[0086] Further, the thickness value of the metal piece 200 when the pole piece 100 is a negative pole piece 100 is introduced below. In some embodiments, the second adhesive layer can refer to Figures 1 to 2 , Figure 1 and Figure 2The positive tab 100 can also be referred to as a negative tab 100. The tab 100 assembly 10 further comprises a second adhesive layer, the tab 100 comprises a negative tab 100, the tab lug 300 comprises a negative tab lug 300, the second adhesive layer covers the negative tab lug 300 and the negative tab 100, the thickness of the metal piece 200 is B, the thickness of the negative tab 100 is K, the thickness of the negative tab lug 300 is K1, the thickness of the foil 120 is K2, the thickness of the second adhesive layer is K3, and 4um≤B≤K-K1-K2-K3. Specifically, the thickness of the metal piece 200 can be 4um, 5um or 8um. It is conceivable that the higher the thickness of the metal piece 200, the higher the welding power after the metal piece 200 and the foil 120 are attached, thereby improving the welding effect. Conversely, when the thickness of the metal piece 200 is less than 4um, it can result in poor welding effect between the foil 120 and the tab lug 300.

[0087] Further, in some embodiments, the tab lug 300 and the second surface 123 have a first welding mark 400, along the length direction of the tab 100, the size of the empty foil area 121 is L1, the size of the metal piece 200 is L2, and the size of the first welding mark 400 is L3, and L1≥L2≥L3. Specifically, along the length direction of the tab 100, if the size of the metal piece 200 is greater than the size of the empty foil area 121, a portion of the metal piece 200 can abut against the active material layer 110, which can result in poor flatness of the tab 100 assembly 10. In addition, the size of the metal piece 200 is less than the size of the empty foil area 121, which can reduce the processing difficulty and improve the processing efficiency.

[0088] Further, in some embodiments, the tab lug 300 and the second surface 123 have a first welding mark 400, along the width direction of the tab 100, the size of the empty foil area 121 is W1, the size of the metal piece 200 is W2, and the size of the first welding mark 400 is W3, and W1≥W2≥W3. Specifically, along the width direction of the tab 100, if the size of the metal piece 200 is greater than the size of the empty foil area 121, a portion of the metal piece 200 can abut against the active material layer 110, which can result in poor flatness of the tab 100 assembly 10. In addition, the size of the metal piece 200 is less than the size of the empty foil area 121, which can reduce the processing difficulty and improve the processing efficiency.

[0089] Further, in some embodiments, the metal piece 200 and the first surface 122 have a second welding mark therebetween, and along the length direction of the pole piece 100, the size of the empty foil area 121 is L4, the size of the metal piece 200 is L5, and the size of the second welding mark is L6, L4≥L5≥L6. Specifically, along the length direction of the pole piece 100, if the size of the metal piece 200 is greater than the size of the empty foil area 121, a part of the metal piece 200 can abut on the active material layer 110, which can cause poor flatness of the pole piece 100 assembly 10. In addition, the size of the metal piece 200 is less than the size of the empty foil area 121, which can reduce the processing difficulty and improve the processing efficiency.

[0090] Further, in some embodiments, the metal piece 200 and the first surface 122 have a second welding mark therebetween, and along the width direction of the pole piece 100, the size of the empty foil area 121 is W4, the size of the metal piece 200 is W5, and the size of the second welding mark is W6, W4≥W5≥W6. Specifically, along the length direction of the pole piece 100, if the size of the metal piece 200 is greater than the size of the empty foil area 121, a part of the metal piece 200 can abut on the active material layer 110, which can cause poor flatness of the pole piece 100 assembly 10. In addition, the size of the metal piece 200 is less than the size of the empty foil area 121, which can reduce the processing difficulty and improve the processing efficiency.

[0091] Specifically, the welding process between the metal piece 200, the tab 300 and the pole piece 100 can be that the foil 120 and the tab 300 can be simultaneously fed by using the upper and lower completely symmetrical tab 300 feeding mechanism, and after feeding, the welding mechanism needs to be pressed down first, and then the tab 300, the foil 120 and the metal piece 200 are stabilized before being ultrasonically welded. Alternatively, after the tab 300, the pole piece 100 and the metal piece 200 are fed, the three are shaped and positioned, and then the tab 300 and the metal piece 200 are adjusted to the position of the empty foil area 121 before being ultrasonically welded. After ultrasonic welding, the tab 300 and the metal piece 200 are welded together at the empty foil area 121 of the pole piece 100.

[0092] In some embodiments, the battery comprises the tab 100 assembly 10 of any of the above embodiments. Specifically, by arranging the metal piece 200 on the first face 122 of the empty foil area 121, and arranging the tab 300 on the second face 123 of the empty foil area 121, when welding the tab 300 and the second face 123, a higher welding power can be used for welding, in the prior art, due to the thin thickness of the foil 120, a higher welding power will cause the foil 120 to be welded broken, but in the present application, when the tab 300 and the foil 120 are welded by a higher welding power, the metal piece 200 can participate in the welding process of the foil 120 and the tab 300, and the metal piece 200 can be penetrated and fused between the tab 300 and the foil 120, which can effectively reduce the probability of the foil 120 being welded broken, thereby improving the welding quality. In this way, this can make the welding quality between the foil 120 and the tab 300 good, and the foil 120 and the tab 300 can have a higher tensile strength. Further, the battery with the tab 100 assembly 10 has higher safety.

[0093] The embodiments of the utility model are described in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range possessed by the ordinary skilled in the art without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

Claims

1. A pole piece assembly characterized by, The application relates to a polar piece assembly. The polar piece comprises an active material layer and a foil, the foil comprises a blank foil area and a coated area, the active material layer is connected to the coated area, and the blank foil area comprises a first face and a second face. A metal piece is welded to the first face. A first welding mark is formed between the tab and the second face, the first welding mark comprises a first sub-welding mark and a second sub-welding mark, and the projection of the first sub-welding mark and the projection of the second sub-welding mark do not overlap in the thickness direction of the tab.

2. The pole piece assembly of claim 1, wherein, The first sub-welding mark and the second sub-welding mark are arranged in an array.

3. The pole piece assembly of claim 2, wherein, The polar piece assembly further comprises a first adhesive layer, the polar piece comprises a positive polar piece, the tab comprises a positive tab, the first adhesive layer covers the positive tab and the positive polar piece, the thickness of the metal piece is A, the thickness of the positive polar piece is H, the thickness of the positive tab is H1, the thickness of the foil is H2, and the thickness of the first adhesive layer is H3, 7um<=A<=H-H1-H2-H3.

4. The pole piece assembly of claim 1, wherein, The polar piece assembly further comprises a second adhesive layer, the polar piece comprises a negative polar piece, the tab comprises a negative tab, the second adhesive layer covers the negative tab and the negative polar piece, the thickness of the metal piece is B, the thickness of the negative polar piece is K, the thickness of the negative tab is K1, the thickness of the foil is K2, and the thickness of the second adhesive layer is K3, 4um<=B<=K-K1-K2-K3.

5. The pole piece assembly of claim 1, wherein, The first welding mark is formed between the tab and the second face, the size of the blank foil area is L1 in the length direction of the polar piece, the size of the metal piece is L2, and the size of the first welding mark is L3, L1>=L2>=L3.

6. The pole piece assembly of claim 1, wherein, The first welding mark is formed between the tab and the second face, the size of the blank foil area is W1 in the width direction of the polar piece, the size of the metal piece is W2, and the size of the first welding mark is W3, W1>=W2>=W3.

7. The pole piece assembly of claim 1, wherein, The second welding mark is formed between the metal piece and the first face, the size of the blank foil area is L4 in the length direction of the polar piece, the size of the metal piece is L5, and the size of the second welding mark is L6, L4>=L5>=L6.

8. The pole piece assembly of claim 1, wherein, The second welding mark is formed between the metal piece and the first face, the size of the blank foil area is W4 in the width direction of the polar piece, the size of the metal piece is W5, and the size of the second welding mark is W6, W4>=W5>=W6.

9. The pole piece assembly of claim 1, wherein, The application further relates to a polar piece assembly comprising the polar piece assembly as claimed in any one of claims 1 to 9.

10. A battery characterized by ​

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