Cell, cell manufacturing method, battery cell, battery pack and electrical apparatus

Abstract

Provided in the present application are a cell, a cell manufacturing method, a battery cell, a battery pack and an electrical apparatus. The cell comprises: multiple layers of positive electrode sheets and multiple layers of negative electrode sheets. Said positive electrode sheets comprise a first positive electrode sheet and a second positive electrode sheet, a first terminal of the first positive electrode sheet in a first direction being provided with a first positive tab, and a second terminal of the second positive electrode sheet in the first direction being provided with a second positive tab, thereby reducing the welding thickness of the positive electrode sheets and improving the welding yield of the positive tabs. Said negative electrode sheets comprise a first negative electrode sheet and a second negative electrode sheet, a first terminal of the first negative electrode sheet in the first direction being provided with a first negative tab, and a second terminal of the second negative electrode sheet in the first direction being provided with a second negative tab, thereby reducing the welding thickness of the negative electrode sheets and improving the welding yield of the negative tabs.

Description

Battery cell, battery cell preparation method, battery monomer, battery pack and electric device This application claims priority to the Chinese patent application No. 202410820682.4, filed on June 24, 2024, and entitled "Battery cell, battery cell preparation method, battery monomer, battery pack and electric device", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery cell, a battery cell preparation method, a battery monomer, a battery pack and an electric device. BACKGROUND

[0002] Blade battery is suitable for various electric devices, including power vehicles and energy storage devices, etc. due to its thin design, so that the above-mentioned electric devices have high energy density.

[0003] In the related art, too many layers of pole pieces in the blade battery will result in too thick pole tabs. Based on this, when welding the pole tabs and the top cover, the welding process cannot be broken through, thereby reducing the welding yield. SUMMARY

[0004] The present application provides a battery cell, a battery cell preparation method, a battery monomer, a battery pack and an electric device, which realizes the welding of the pole tabs in the multi-layer pole pieces and improves the welding yield of the pole tabs.

[0005] In a first aspect, the present application provides a battery cell, comprising: a plurality of positive pole pieces and a plurality of negative pole pieces. The positive pole pieces comprise a first positive pole piece and a second positive pole piece. The first positive pole piece is provided with a first positive pole tab at a first end thereof along a first direction, and the second positive pole piece is provided with a second positive pole tab at a second end thereof along the first direction. The negative pole pieces comprise a first negative pole piece and a second negative pole piece, the first negative pole piece is provided with a first negative pole tab at a first end thereof along the first direction, and the second negative pole piece is provided with a second negative pole tab at a second end thereof along the first direction. The plurality of positive pole pieces and the plurality of negative pole pieces are stacked along a second direction, and the second direction is perpendicular to the first direction. The first positive pole tab and the first negative pole tab are both welded in a first welding area of the battery monomer, and the first welding area is arranged at a first end of the battery cell along the first direction. The second positive pole tab and the second negative pole tab are both welded in a second welding area of the battery monomer, and the second welding area is arranged at a second end of the battery cell along the first direction.

[0006] The first positive tab and the first negative tab are spaced apart in a third direction. The third direction is perpendicular to the first direction and the second direction. The second positive tab and the second negative tab are spaced apart in the third direction.

[0007] Similarly, the first negative tab and the first welding area are located at the first end of the battery cell in the first direction, so that the first negative tab on the first negative tab is welded with the first welding area. The second negative tab and the second welding area are located at the second end of the battery cell in the first direction, so that the second negative tab on the second negative tab is welded with the second welding area, thereby reducing the welding thickness of the negative tab and improving the welding yield of the negative tab.

[0008] In a possible design, the first positive tab and the first negative tab are spaced apart in a third direction. The third direction is perpendicular to the first direction and the second direction. The second positive tab and the second negative tab are spaced apart in the third direction.

[0009] Based on the description of the above embodiment, the first positive tab and the first negative tab are spaced apart in the third direction, and the second positive tab and the second negative tab are spaced apart in the third direction, so as to avoid the contact between the positive tab and the negative tab to cause short circuit in the battery.

[0010] In a possible design, a plurality of layers of the first positive tab and a plurality of layers of the first negative tab form a first core stack, and a plurality of layers of the second positive tab and a plurality of layers of the second negative tab form a second core stack. Alternatively, a plurality of layers of the first positive tab and a plurality of layers of the second negative tab form a first core stack, and a plurality of layers of the second positive tab and a plurality of layers of the first negative tab form a second core stack. The first core stack is placed on the second core stack along the second direction. The battery cell can include one or more first core stacks. The battery cell can include one or more second core stacks.

[0011] Based on the description of the above embodiment, the battery cell includes one or more first core stacks and one or more second core stacks, so that the operator can flexibly assemble different structures and different numbers of first core stacks and second core stacks, thereby forming a plurality of battery cells.

[0012] In a possible design, one layer of the first positive tab, one layer of the first negative tab, one layer of the second positive tab, and one layer of the second negative tab are stacked along the second direction to form a third core stack. The battery cell includes a plurality of the third core stacks.

[0013] Based on the above description of the embodiments, the first positive lug, the second positive lug, the first negative lug and the second negative lug after pre-welding generally need to be trimmed. Based on this, one layer of the first positive plate, one layer of the first negative plate, one layer of the second positive plate and one layer of the second negative plate are stacked along the second direction to form a third core. The first positive plate, the second positive plate, the first negative plate and the second negative plate in the third core are uniformly arranged in the second direction. After pre-welding of the plurality of first positive lugs, the plurality of second positive lugs, the plurality of first negative lugs and the plurality of second negative lugs, they can be located at the same height without the need for trimming.

[0014] In a possible design, the number of the first positive plate, the second positive plate, the first negative plate and the second negative plate is less than or equal to 50.

[0015] Based on the above description of the embodiments, when the number of the plates is more than 50, the existing welding process cannot be broken through, resulting in a low lug welding yield. Based on this, the number of the first positive plate, the second positive plate, the first negative plate and the second negative plate is less than or equal to 50, which can improve the welding yield of the first positive lug, the second positive lug, the first negative lug and the second negative lug.

[0016] In a possible design, the first welding area is a first top cover in the battery monomer, and the second welding area is a second top cover in the battery monomer. Alternatively, the first welding area is a first connecting sheet, and the second welding area is a second connecting sheet.

[0017] The lug generally includes two welding methods.

[0018] The first method is to directly weld the lug on the top cover. The second method is to weld the lug on the connecting sheet, and then weld the connecting sheet on the top cover.

[0019] In a second aspect, the application provides a method for preparing an electric core, which is used for preparing the electric core described in any of the above embodiments, and the method comprises the following steps:

[0020] Obtaining a positive plate, a negative plate and a separator, wherein the positive plate comprises a first positive plate and a second positive plate, and the negative plate comprises a first negative plate and a second negative plate.

[0021] Stacking the positive plate, the separator and the negative plate in sequence along the second direction, so that the first positive lug in the first positive plate and the first negative lug in the first negative plate are located at the first end of the electric core in the first direction, and the second positive lug in the second positive plate and the second negative lug in the second negative plate are located at the second end of the electric core in the first direction.

[0022] The pre-welded multi-layer first positive tab, the pre-welded multi-layer first negative tab, the pre-welded multi-layer second positive tab, and the pre-welded multi-layer second negative tab.

[0023] The first welding area and the second welding area are obtained, the first welding area is located at a first end of the battery cell in the first direction, and the second welding area is located at a second end of the battery cell in the first direction.

[0024] The pre-welded multi-layer first positive tab and the pre-welded multi-layer first negative tab are welded at the first welding area.

[0025] The pre-welded multi-layer second positive tab and the pre-welded multi-layer second negative tab are welded at the second welding area.

[0026] In a third aspect, the present application provides a battery cell, comprising a first top cover, a second top cover, and the battery cell in any of the above embodiments. The first top cover is arranged at a first end of the battery cell in the first direction. The second top cover is arranged at a second end of the battery cell in the first direction. The first top cover, the second top cover, and the battery cell are arranged in the shell.

[0027] In a fourth aspect, the present application provides a battery pack, comprising the battery cell in the above embodiments. The battery pack is provided with one or more battery cells.

[0028] In a fifth aspect, the present application provides a power utilization device, comprising the battery pack in the above embodiments. The battery pack is used to provide electric energy.

[0029] The beneficial effects of the second aspect, the third aspect, the fourth aspect, and the fifth aspect provided above can refer to the beneficial effects brought by the first aspect and the possible implementation manners of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0031] FIG. 1 is a kind of assembly schematic view of battery cell, first top cover and second top cover in the embodiment of the present application.

[0032] FIG. 2 is a kind of structure schematic view of battery cell (third core stack) in the embodiment of the present application.

[0033] FIG. 3 is a kind of structure schematic view of first positive sheet in the embodiment of the present application.

[0034] Fig. 4 is a schematic view of another structure of the first positive plate in the embodiment of the present application.

[0035] Fig. 5 is a schematic view of a structure of the second positive plate in the embodiment of the present application.

[0036] Fig. 6 is a schematic view of another structure of the second positive plate in the embodiment of the present application.

[0037] Fig. 7 is a schematic view of a structure of the first negative plate in the embodiment of the present application.

[0038] Fig. 8 is a schematic view of another structure of the first negative plate in the embodiment of the present application.

[0039] Fig. 9 is a schematic view of a structure of the second negative plate in the embodiment of the present application.

[0040] Fig. 10 is a schematic view of another structure of the second negative plate in the embodiment of the present application.

[0041] Fig. 11 is a schematic view of a first structure of the first core stack in the embodiment of the present application.

[0042] Fig. 12 is a schematic view of a second structure of the first core stack in the embodiment of the present application.

[0043] Fig. 13 is a schematic view of a first structure of the second core stack in the embodiment of the present application.

[0044] Fig. 14 is a schematic view of a second structure of the second core stack in the embodiment of the present application.

[0045] Fig. 15 is a schematic view of a third structure of the first core stack in the embodiment of the present application.

[0046] Fig. 16 is a schematic view of another third structure of the first core stack in the embodiment of the present application.

[0047] Fig. 17 is a schematic view of a fourth structure of the first core stack in the embodiment of the present application.

[0048] Fig. 18 is a schematic view of another fourth structure of the first core stack in the embodiment of the present application.

[0049] Fig. 19 is a schematic view of a third structure of the second core stack in the embodiment of the present application.

[0050] Fig. 20 is a schematic view of another third structure of the second core stack in the embodiment of the present application.

[0051] Fig. 21 is a schematic view of a fourth structure of the second core stack in the embodiment of the present application.

[0052] Fig. 22 is a schematic view of another fourth structure of the second core stack in the embodiment of the present application.

[0053] Fig. 23 is a schematic view of a second structure of the third core in the embodiment of the present application.

[0054] Fig. 24 is a schematic view of a third structure of the third core in the embodiment of the present application.

[0055] Fig. 25 is a schematic view of a fourth structure of the third core in the embodiment of the present application.

[0056] Legend of reference signs:

[0057] 100 - cell; 1 - positive plate; 11 - first positive plate; 111 - first positive tab; 12 - second positive plate; 121 - second positive tab; 2 - negative plate; 21 - first negative plate; 211 - first negative tab; 22 - second negative plate; 221 - second negative tab; 3 - first core; 4 - second core; 5 - third core; 6 - first top cover; 7 - second top cover; X - first direction; Y - second direction; Z - third direction. DETAILED DESCRIPTION

[0058] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description herein is for describing the specific embodiments only and not intended to be limiting of the application.

[0060] The terms "comprise" and "have" and any variations thereof in the specification and claims of the present application and the description of the drawings are intended to cover but not exclude other content. The word "one" or "a" does not exclude the presence of more than one.

[0061] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. A person of ordinary skill in the art will readily recognize from the disclosure herein, given the total volume of this application that one or more passages that are described in connection with an embodiment can be combined with one or more other passages to change, modify or refine an embodiment consequently falling within the scope of the application.

[0062] The term "and / or", merely describes an associated relationship, and means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " generally represents an "or" relationship between the front and rear associated objects.

[0063] The orientation words appearing in the following description are the directions shown in the drawings, and are not specific structures of the present application. For example, in the description of the present application, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0064] In addition, the expressions of the indicating directions for describing the operation and structure of each component of the present embodiment, such as the X direction, the Y direction and the Z direction, are not absolute but relative, and although these indications are appropriate when each component of the battery pack is in the position shown in the drawings, these directions should be interpreted differently to correspond to the changes when these positions change.

[0065] In addition, the terms "first", "second", and the like in the specification and claims of the present application or the above drawings are used to distinguish different objects, and are not used to describe a particular order, and can explicitly or implicitly include one or more of the features.

[0066] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more (including two), and similarly, "a plurality of groups" means two or more groups (including two groups).

[0067] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, the "connection" or "connecting" of mechanical structures can mean physical connection, for example, the physical connection can be fixed connection, for example, fixed connection by screws, bolts or other fixing members; the physical connection can also be detachable connection, for example, mutual clamping or clamping connection; the physical connection can also be integrally connected, for example, welding, bonding or integrally formed connection. The "connection" or "connecting" of circuit structures can mean not only physical connection, but also electrical connection or signal connection, for example, it can be direct connection, that is, physical connection, or indirect connection through at least one intermediate element, as long as the circuit is connected, it can also be the connection inside two elements; signal connection can not only be signal connection through circuit, but also signal connection through media medium, for example, radio wave. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0068] An electrical appliance refers to an electrical device that uses electrical energy to perform a specific function. Electrical appliances can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric cars, electric vehicles, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric plane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc. The above devices are powered by connecting to a power source to provide various functions or services.

[0069] A battery pack, also known as a battery module or battery array, is a complete unit composed of multiple battery cells (such as lithium-ion battery cells) connected in series and / or parallel in a specific manner. This complete unit is designed to provide higher voltage and greater capacity to meet the needs of various applications, such as electric vehicles, energy storage systems, drones, etc.

[0070] A battery cell refers to the basic unit that makes up a battery pack, usually referring to a chemical device that can generate electrical energy. In a battery pack, multiple battery cells are connected in series or parallel to form the required voltage and current. For example, the AA battery we commonly see is a single battery cell that contains chemical substances inside that can convert chemical energy into electrical energy.

[0071] The blade battery is a type of lithium ion battery with a flat shape similar to a blade. The blade battery can include a shell, a cell, and two top covers, and the cell and the top covers are arranged in the shell. The cell includes a positive electrode sheet, a negative electrode sheet, and a separator. The plurality of layers of the positive electrode sheet, the plurality of layers of the negative electrode sheet, and the plurality of layers of the separator are stacked together to form a cell structure. Among them, all the positive electrode sheets are provided with positive electrode tabs, and all the negative electrode sheets are provided with negative electrode tabs. During the preparation of the cell of the blade battery, all the positive electrode tabs and all the negative electrode tabs need to be welded on the top cover. The excessive number of layers of the positive electrode sheet or the negative electrode sheet makes the thickness of the positive electrode tab or the negative electrode tab too thick, and the existing welding process cannot break through, thereby causing the problem of low tab welding yield.

[0072] In order to solve the problem of low welding yield of the ultra-thick tab, the embodiments of the present application provide a cell, a cell preparation method, a battery monomer, a battery pack and an electric device. By welding the positive electrode tab at the opposite ends of the positive electrode sheet and welding the negative electrode tab at the opposite ends of the negative electrode sheet, the thickness of the positive electrode tab and the negative electrode tab is reduced to improve the welding yield of the tab. The following will be described in detail in conjunction with the accompanying drawings 1-25 of the specification.

[0073] In a first aspect, as shown in FIGS. 1-10, the present application provides a cell 100, comprising: a plurality of layers of positive electrode sheets 1, a plurality of layers of negative electrode sheets 2, and a plurality of layers of separators (not shown in the figure). The positive electrode sheet 1 includes a first positive electrode sheet 11 and a second positive electrode sheet 12. The first positive electrode sheet 11 is provided with a first positive electrode tab 111 at the first end thereof along a first direction X, and the second positive electrode sheet 12 is provided with a second positive electrode tab 121 at the second end thereof along the first direction X. The negative electrode sheet 2 includes a first negative electrode sheet 21 and a second negative electrode sheet 22, and the first negative electrode sheet 21 is provided with a first negative electrode tab 211 at the first end thereof along the first direction X, and the second negative electrode sheet 22 is provided with a second negative electrode tab 221 at the second end thereof along the first direction X. The separator is arranged between the positive electrode sheet 1 and the negative electrode sheet 2, and the plurality of layers of positive electrode sheets 1, the plurality of layers of negative electrode sheets 2, and the plurality of layers of separators are stacked along a second direction Y, wherein the second direction Y is perpendicular to the first direction X. The first positive electrode tab 111 and the first negative electrode tab 211 are both welded in a first welding area (not shown in the figure), and the first welding area is arranged at the first end of the cell 100 along the first direction X. The second positive electrode tab 121 and the second negative electrode tab 221 are both welded in a second welding area (not shown in the figure) of the battery monomer, and the second welding area is arranged at the second end of the cell 100 along the first direction X.

[0074] Positive electrode sheet: The positive electrode sheet is mainly composed of active material, conductive agent, binder and the like. These components are mixed into slurry, coated on the current collector (usually aluminum foil or copper foil) to make it. The positive electrode sheet is located on the anode side of the battery.

[0075] During the charging and discharging process, the active material on the positive electrode sheet participates in the chemical reaction, releases or receives electrons, thereby realizing the storage and release of energy.

[0076] Negative electrode sheet: The negative electrode sheet is mainly composed of active materials, conductive agents, binders, etc. These components are mixed into a slurry and coated on a current collector (usually a copper foil) to make it. The negative electrode sheet is located on the cathode side of the battery.

[0077] During charging and discharging, the active material on the negative electrode sheet receives electrons from the external circuit and participates in chemical reactions to store energy.

[0078] Separator: The separator is located between the positive and negative electrode sheets of the battery and is a very thin and porous material that allows gas to pass through. The separator is used to separate the positive and negative electrode sheets to prevent direct contact between them and cause short circuits, while allowing lithium ions or other charged particles to pass freely.

[0079] The material of the separator is usually selected from materials with high chemical corrosion resistance, low resistance, high mechanical strength, and good thermal stability, such as polyolefins, ceramic-coated polyolefins, or fluoropolymers.

[0080] Positive tab: The positive tab is connected to one side of the positive electrode sheet. When the battery monomer or battery pack is connected in series, all the positive tabs will be connected to each other to form a complete circuit, allowing charges to flow throughout the battery pack.

[0081] Negative tab: The negative tab is connected to one side of the negative electrode sheet and has a similar function to the positive tab, responsible for connecting the negative electrode sheet to other negative electrode sheets within the battery pack or external circuit.

[0082] The battery cell 100 can include a plurality of stacked units. As shown in FIG. 1, the second direction Y is the height direction of the battery cell 100. One stacked unit can include a layer of positive electrode sheet 1, a layer of separator, a layer of negative electrode sheet 2, and a layer of separator stacked in sequence along the second direction Y. Specifically, the positive electrode sheet 1 can be divided into a first positive electrode sheet 11 and a second positive electrode sheet 12, and the negative electrode sheet 2 can be divided into a first negative electrode sheet 21 and a second negative electrode sheet 22.

[0083] As shown in FIG. 2, the first positive electrode sheet 11 is provided with a first positive tab 111 at a first end along the first direction X, and the second positive electrode sheet 12 is provided with a second positive tab 121 at a second end along the first direction X. The first negative electrode sheet 21 is provided with a first negative tab 211 at one end along the first direction X, and the second negative electrode sheet 22 is provided with a second negative tab 221 at a second end along the first direction X. The first direction X is the length direction of the battery cell 100, and since the battery cell 100 is composed of a plurality of layers of positive electrode sheets 1 and negative electrode sheets 2, the first direction X can also be the length direction of the positive electrode sheets 1 and negative electrode sheets 2. Similarly, the second direction Y can also be the thickness direction of the positive electrode sheets 1 and negative electrode sheets 2.

[0084] As can be seen from the above, the first positive tab 111, the first negative tab 211 and the first welding area are all located at the first end of the battery cell 100 in the first direction X. Therefore, the first positive tab 111 and the first negative tab 211 can be welded at the first welding area.

[0085] The second positive tab 121, the second negative tab 221 and the second welding area are all located at the second end of the battery cell 100 in the first direction X. Therefore, the second positive tab 121 and the second negative tab 221 can be welded at the second welding area.

[0086] In summary, since the positive tab and the negative tab are too thick, the welding yield of the tab is low. Based on this, the positive plate 1 is divided into a first positive plate 11 and a second positive plate 12. The first positive tab 111 and the first welding area are all located at the first end of the battery cell 100 in the first direction X, so that the first positive tab 111 on the first positive plate 11 is welded with the first welding area. The second positive tab 121 and the second welding area are all located at the second end of the battery cell 100 in the first direction X, so that the second positive tab 121 on the second positive plate 12 is welded with the second welding area, thereby reducing the welding thickness of the positive plate 1 and improving the welding yield of the positive tab.

[0087] Similarly, the negative plate 2 is divided into a first negative plate 21 and a second negative plate 22. The first negative tab 211 and the first welding area are all located at the first end of the battery cell 100 in the first direction X, so that the first negative tab 211 on the first negative plate 21 is welded with the first welding area. The second negative tab 221 and the second welding area are all located at the second end of the battery cell 100 in the first direction X, so that the second negative tab 221 on the second negative plate 22 is welded with the second welding area, thereby reducing the welding thickness of the negative plate 2 and improving the welding yield of the negative tab.

[0088] In some embodiments, the first positive tab 111 and the first negative tab 211 are spaced apart in a third direction Z. The third direction Z is perpendicular to the first direction X and the second direction Y. The second positive tab 121 and the second negative tab 221 are spaced apart in the third direction Z.

[0089] Since the first positive tab 111 and the first negative tab 211 are both welded at the first welding area, the first positive tab 111 and the first negative tab 211 are spaced apart in the third direction Z, so that the first positive tab 111 and the first negative tab 211 can be welded at the first welding area in sequence along the third direction Z, avoiding the first positive tab 111 and the first negative tab 211 from contacting during welding, thereby avoiding short circuit between the first positive tab 111 and the first negative tab 211. The third direction Z is the width direction of the battery cell 100, and can also be the width direction of the positive plate 1 and the negative plate 2.

[0090] Similarly, since the second positive tab 121 and the second negative tab 221 are both welded in the second welding area, the second positive tab 121 and the second negative tab 221 are spaced apart in the third direction Z, so that the second positive tab 121 and the second negative tab 221 can be welded in the second welding area in the third direction Z in turn, avoiding contact between the second positive tab 121 and the second negative tab 221 during welding, thereby avoiding short circuit between the second positive tab 121 and the second negative tab 221.

[0091] Specifically, the present application does not specifically limit the positions of the first positive tab 111, the second positive tab 121, the first negative tab 211 and the second negative tab 221 in the third direction Z.

[0092] Therefore, the first positive tab 11 can include two structures as shown in FIGS. 3 and 4. The first positive tab 111 in FIG. 3 is close to one side of the first positive tab 11 in the third direction Z, and the first positive tab 111 in FIG. 4 is close to the other side of the first positive tab 11 in the third direction Z.

[0093] Therefore, the second positive tab 12 can include two structures as shown in FIGS. 5 and 6. The second positive tab 121 in FIG. 5 is close to one side of the second positive tab 12 in the third direction Z, and the second positive tab 121 in FIG. 6 is close to the other side of the second positive tab 12 in the third direction Z.

[0094] Therefore, the first negative tab 21 can include two structures as shown in FIGS. 7 and 8. The first negative tab 211 in FIG. 7 is close to one side of the first negative tab 21 in the third direction Z, and the first negative tab 211 in FIG. 8 is close to the other side of the first negative tab 21 in the third direction Z.

[0095] Therefore, the second negative tab 22 can include two structures as shown in FIGS. 9 and 10. The second negative tab 221 in FIG. 9 is close to one side of the second negative tab 22 in the third direction Z, and the second negative tab 221 in FIG. 10 is close to the other side of the second negative tab 22 in the third direction Z.

[0096] In summary, the first positive tab 111 and the first negative tab 211 are spaced apart in the third direction Z, and the second positive tab 121 and the second negative tab 221 are spaced apart in the third direction Z, avoiding contact between the positive tab 1 and the negative tab 2 to cause short circuit in the battery.

[0097] Further, the first positive tab 111, the second positive tab 121, the first negative tab 211 and the second negative tab 221 of the above different structures can form a plurality of forms of the battery cell 100, two of which will be introduced below in combination with FIGS. 11-25. It should be noted that the form of the battery cell 100 in the present application includes but is not limited to the following two forms.

[0098] Figures 11-22 embody a form of the battery cell 100:

[0099] In some embodiments, the multi-layer first positive tab 111, the multi-layer separator, and the multi-layer first negative tab 211 constitute a first stack 3, and the multi-layer second positive tab 121, the multi-layer separator, and the multi-layer second negative tab 221 constitute a second stack 4. Alternatively, the multi-layer first positive tab 111, the multi-layer separator, and the multi-layer second negative tab 221 constitute the first stack 3, and the multi-layer second positive tab 121, the multi-layer separator, and the multi-layer first negative tab 211 constitute the second stack 4. The first stack 3 is placed on the second stack 4 along the second direction Y. One or more first stacks 3 can be included in the battery cell 100. One or more second stacks 4 can be included in the battery cell 100.

[0100] The first stack 3 can include one or more first stack units, and the second stack 4 can include one or more second stack units. The first stack units and the second stack units can include the following two combinations.

[0101] Figures 11-14 show a first combination: one first stack unit can include a layer of the first positive sheet 11, a layer of the separator, a layer of the first negative sheet 21, and a layer of the separator, which are sequentially stacked along the second direction Y. One second stack unit can include a layer of the second positive sheet, a layer of the separator, a layer of the second negative sheet 22, and a layer of the separator, which are sequentially stacked along the second direction Y.

[0102] Specifically, the present scheme does not specifically limit the positions of the first positive tab 111 and the first negative tab 211 in the third direction Z.

[0103] Therefore, the above-mentioned first stack 3 can include the following two structures.

[0104] As shown in Figure 11, the first structure of the first stack 3 is that the first positive tab 111 and the first negative tab 211 are located at the first end of the first stack 3 in the first direction X. Moreover, the first positive tab 111 is close to one side of the first stack 3 in the third direction Z, and the first negative tab 211 is close to the other side of the first stack 3 in the third direction Z.

[0105] As shown in Figure 12, the second structure of the first stack 3 is that the first positive tab 111 and the first negative tab 211 are located at the first end of the first stack 3 in the first direction X. Moreover, the first negative tab 211 is close to one side of the first stack 3 in the third direction Z, and the first positive tab 111 is close to the other side of the first stack 3 in the third direction Z.

[0106] Similarly, the present scheme does not specifically limit the positions of the second positive tab 121 and the second negative tab 221 in the third direction Z.

[0107] Therefore, the second stack core 4 described above can include the following two structures.

[0108] As shown in FIG. 13, the first structure of the second stack core 4 is that the second positive tab 121 and the second negative tab 221 are located at the second end of the second stack core 4 in the first direction X. And the second positive tab 121 is close to one side of the second stack core 4 in the third direction Z, and the second negative tab 221 is close to the other side of the second stack core 4 in the third direction Z.

[0109] As shown in FIG. 14, the second structure of the second stack core 4 is that the second positive tab 121 and the second negative tab 221 are located at the second end of the second stack core 4 in the first direction X. And the second negative tab 221 is close to one side of the second stack core 4 in the third direction Z, and the second positive tab 121 is close to the other side of the second stack core 4 in the third direction Z.

[0110] FIGS. 15-22 are a second combination: one first stack unit can include a layer of first positive sheet 11, a layer of separator, a layer of second negative sheet 22, and a layer of separator, which are sequentially stacked along the second direction Y. One second stack unit can include a layer of second positive sheet 12, a layer of separator, a layer of first negative sheet 21, and a layer of separator, which are sequentially stacked along the second direction Y.

[0111] Similarly, the first stack core 3 described above can include the following two structures.

[0112] As shown in FIGS. 15 and 16, the third structure of the first stack core 3 is that the first positive tab 111 is located at the first end of the first stack core 3 in the first direction X, and the second negative tab 221 is located at the second end of the first stack core 3 in the first direction X. And the first positive tab 111 is close to one side of the first stack core 3 in the third direction Z, and the second negative tab 221 is close to one side of the first stack core 3 in the third direction Z as shown in FIG. 15 or the other side as shown in FIG. 16.

[0113] As shown in FIGS. 17 and 18, the fourth structure of the first stack core 3 is that the first positive tab 111 is located at the first end of the first stack core 3 in the first direction X, and the second negative tab 221 is located at the second end of the first stack core 3 in the first direction X. And the second negative tab 221 is close to one side of the first stack core 3 in the third direction Z, and the first positive tab 111 is close to one side of the first stack core 3 in the third direction Z as shown in FIG. 17 or the other side as shown in FIG. 18.

[0114] Similarly, the second stack core 4 described above can include the following two structures:

[0115] In the third structure of the second jelly-roll 4, as shown in FIGS. 19 and 20, the second positive tab 121 is located at the second end of the second jelly-roll 4 in the first direction X, and the first negative tab 211 is located at the first end of the second jelly-roll 4 in the first direction X. In addition, the second positive tab 121 is close to one side of the second jelly-roll 4 in the third direction Z, and the first negative tab 211 is close to the side of the second jelly-roll 4 in the third direction Z as shown in FIG. 19 or the other side as shown in FIG. 20.

[0116] In the fourth structure of the second jelly-roll 4, as shown in FIGS. 21 and 22, the second positive tab 121 is located at the second end of the second jelly-roll 4 in the first direction X, and the first negative tab 211 is located at the first end of the second jelly-roll 4 in the first direction X. In addition, the first negative tab 211 is close to one side of the second jelly-roll 4 in the third direction Z, and the second positive tab 121 is close to the side of the second jelly-roll 4 in the third direction Z as shown in FIG. 21 or the other side as shown in FIG. 22.

[0117] According to the above, the first structure of the first jelly-roll 3 can be combined with the first structure of the second jelly-roll 4 to form one of the above-mentioned forms of the battery cell 100, and the first structure of the first jelly-roll 3 can be combined with the second structure of the second jelly-roll 4 to form another of the above-mentioned forms of the battery cell 100.

[0118] In summary, the battery cell 100 includes one or more first jelly-rolls 3 and one or more second jelly-rolls 4, so that the operator can flexibly assemble different structures and different numbers of first jelly-rolls 3 and second jelly-rolls 4 to form various battery cells 100.

[0119] FIGS. 1, 23-25 show the second form of the battery cell 100.

[0120] In some embodiments, one layer of the first positive sheet 11, one layer of the separator, one layer of the first negative sheet 21, one layer of the separator, one layer of the second positive sheet 12, one layer of the separator, one layer of the second negative sheet 22, and one layer of the separator are stacked along the second direction Y to form a third jelly-roll 5. The battery cell 100 can include a plurality of third jelly-rolls 5.

[0121] The third jelly-roll 5 can include four structures. In the four structures, the first positive tab 111 and the first negative tab 211 are both located at the first end of the third jelly-roll 5 in the first direction X. The second positive tab 121 and the second negative tab 221 are both located at the second end of the third jelly-roll 5 in the first direction X. Therefore, the following content only further limits the positions of the first positive tab 111, the second positive tab 121, the first negative tab 211, and the second negative tab 221 in the third direction Z.

[0122] As shown in FIG. 1, the first structure of the third core 5 is that the first positive tab 111 and the second negative tab 221 are close to one side of the third core 5 in the third direction Z, and the second positive tab 121 and the first negative tab 211 are close to the other side of the third core 5 in the third direction Z.

[0123] As shown in FIG. 23, the second structure of the third core 5 is that the second positive tab 121 and the first negative tab 211 are close to one side of the third core 5 in the third direction Z, and the first positive tab 111 and the second negative tab 221 are close to the other side of the third core 5 in the third direction Z.

[0124] As shown in FIG. 24, the third structure of the third core 5 is that the first positive tab 111 and the second positive tab 121 are close to one side of the third core 5 in the third direction Z, and the first negative tab 211 and the second negative tab 221 are close to the other side of the third core 5 in the third direction Z.

[0125] As shown in FIG. 25, the fourth structure of the third core 5 is that the first negative tab 211 and the second negative tab 221 are close to one side of the third core 5 in the third direction Z, and the first positive tab 111 and the second positive tab 121 are close to the other side of the third core 5 in the third direction Z.

[0126] It should be noted that the first positive sheet 11 and the second positive sheet 12 in the above embodiment can be interchanged in the stacking order. Similarly, the first negative sheet 21 and the second negative sheet 22 in the above embodiment can be interchanged in the stacking order.

[0127] According to the above, the first positive sheet 11, the second positive sheet 12, the first negative sheet 21 and the second negative sheet 22 in the third core 5 are uniformly arranged in the second direction Y.

[0128] In summary, the first positive tab 111, the second positive tab 121, the first negative tab 211 and the second negative tab 221 after pre-welding generally need to be trimmed. Based on this, a layer of first positive sheet 11, a layer of separator, a layer of first negative sheet 21, a layer of separator, a layer of second positive sheet 12, a layer of separator, a layer of second negative sheet 22 and a layer of separator are stacked along the second direction Y to form the third core 5. So that the first positive sheet 11, the second positive sheet 12, the first negative sheet 21 and the second negative sheet 22 in the third core 5 are uniformly arranged in the second direction Y. After pre-welding of the plurality of first positive tabs 111, the plurality of second positive tabs 121, the plurality of first negative tabs 211 and the plurality of second negative tabs 221, they can be located at the same height without the need for trimming.

[0129] In some embodiments, when the number of positive electrode sheets 1 in the third stack 5 is even, the number of first positive electrode tabs 111 is equal to the number of second positive electrode tabs 121. When the number of positive electrode sheets 1 in the third stack 5 is odd, the number of first positive electrode tabs 111 is one more than the number of second positive electrode tabs 121, or the number of first positive electrode tabs 111 is one less than the number of second positive electrode tabs 121.

[0130] When the number of negative electrode sheets 2 in the third stack 5 is even, the number of first negative electrode tabs 211 is equal to the number of second negative electrode tabs 221. When the number of negative electrode sheets 2 in the third stack 5 is odd, the number of first positive electrode tabs 111 is one more than the number of second positive electrode tabs 121, or the number of first positive electrode tabs 111 is one less than the number of second positive electrode tabs 121.

[0131] For example, the third stack 5 includes 50 layers of positive electrode tabs and 51 layers of negative electrode tabs. The first positive electrode tabs 111 are 25 layers, the second positive electrode tabs 121 are 25 layers, the first negative electrode tabs 211 are 25 layers, and the second negative electrode tabs 221 are 26 layers. Alternatively, the first positive electrode tabs 111 are 25 layers, the second positive electrode tabs 121 are 25 layers, the first negative electrode tabs 211 are 26 layers, and the second negative electrode tabs 221 are 25 layers.

[0132] In some embodiments, the number of first positive electrode sheets 11, second positive electrode sheets 12, first negative electrode sheets 21, and second negative electrode sheets 22 is less than or equal to 50.

[0133] When the number of electrode sheets is greater than 50 layers, the existing welding process cannot be broken through, resulting in low tab welding yield. Therefore, the number of first positive electrode sheets 11, second positive electrode sheets 12, first negative electrode sheets 21, and second negative electrode sheets 22 is less than or equal to 50, which can improve the welding yield of first positive electrode tabs 111, second positive electrode tabs 121, first negative electrode tabs 211, and second negative electrode tabs 221.

[0134] In some embodiments, the first welding area is the first top cover 6 in the battery cell, and the second welding area is the second top cover 7 in the battery cell. Alternatively, the first welding area is the first connecting sheet, and the second welding area is the second connecting sheet.

[0135] The tab generally includes two welding methods.

[0136] The first method is to weld the tab directly on the top cover. The second method is to weld the tab on the connecting sheet, and then weld the connecting sheet on the top cover. The welding method of the tab is not limited in the present application.

[0137] For example, as shown in FIG. 1, the first welding area is the first top cover 6 in the battery monomer, and the second welding area is the second top cover 7 in the battery monomer. The first positive tab 111 and the first negative tab 211 are sequentially welded on the first top cover 6 along the third direction Z, and the second positive tab 121 and the second negative tab 221 are sequentially welded on the second top cover 7 along the third direction Z.

[0138] In a second aspect, the present application provides a method for preparing an electric core, which is used for preparing the electric core in any one of the above embodiments, and the method comprises the following steps:

[0139] Step one: obtaining a positive sheet, a negative sheet and a diaphragm, wherein the positive sheet comprises a first positive sheet and a second positive sheet, and the negative sheet comprises a first negative sheet and a second negative sheet.

[0140] Step two: sequentially stacking the positive sheet, the diaphragm and the negative sheet along the second direction, so that the first positive tab in the first positive sheet and the first negative tab in the first negative sheet are located at one end of the electric core in the first direction, and the second positive tab in the second positive sheet and the second negative tab in the second negative sheet are located at the second end of the electric core in the first direction.

[0141] Step three: pre-welding the plurality of first positive tabs, pre-welding the plurality of first negative tabs, pre-welding the plurality of second positive tabs and pre-welding the plurality of second negative tabs.

[0142] Step four: obtaining a first welding area and a second welding area, so that the first welding area is located at the first end of the electric core in the first direction, and the second welding area is located at the second end of the electric core in the first direction.

[0143] Step five: welding the plurality of pre-welded first positive tabs and the plurality of pre-welded first negative tabs at the first welding area.

[0144] Step six: welding the plurality of pre-welded second positive tabs and the plurality of pre-welded second negative tabs at the second welding area.

[0145] Those skilled in the art can understand that, although some embodiments herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0146] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, used in a single battery cell, characterized in that, include: Multilayer positive electrode and multilayer negative electrode; The positive electrode includes a first positive electrode and a second positive electrode; The first positive electrode plate has a first positive electrode tab at its first end along the first direction, and the second positive electrode plate has a second positive electrode tab at its second end along the first direction; The negative electrode plate includes a first negative electrode plate and a second negative electrode plate. The first negative electrode plate has a first negative electrode tab at a first end along the first direction, and the second negative electrode plate has a second negative electrode tab at a second end along the first direction. The multilayer positive electrode and multilayer negative electrode are stacked along a second direction, which is perpendicular to the first direction; Both the first positive tab and the first negative tab are welded to the first welding area of ​​the battery cell, and the first welding area is disposed at the first end of the cell along the first direction. Both the second positive tab and the second negative tab are welded to the second welding area of ​​the battery cell, and the second welding area is disposed at the second end of the cell along the first direction.

2. The battery cell according to claim 1, characterized in that, The first positive electrode tab and the first negative electrode tab are spaced apart in a third direction, and the third direction is perpendicular to the first direction and the second direction; The second positive electrode and the second negative electrode are spaced apart in the third direction.

3. The battery cell according to claim 2, characterized in that, The first positive electrode tab and the first negative electrode tab are multi-layered to form a first core, and the second positive electrode tab and the second negative electrode tab are multi-layered to form a second core. or; A first core is formed by multiple layers of the first positive electrode tab and multiple layers of the second negative electrode tab, and a second core is formed by multiple layers of the second positive electrode tab and multiple layers of the first negative electrode tab. The first stack of cores is placed on the second stack of cores along the second direction; The battery cell includes one or more first stacked cores; The battery cell includes one or more second stacked cores.

4. The battery cell according to claim 2, characterized in that, A first positive electrode layer, a first negative electrode layer, a second positive electrode layer, and a second negative electrode layer are stacked along the second direction to form a third core; The battery cell includes multiple third stacked cores.

5. The battery cell according to claim 1, characterized in that, The number of the first positive electrode, the second positive electrode, the first negative electrode, and the second negative electrode is less than or equal to 50.

6. The battery cell according to claim 1, characterized in that, The first welding area is the first top cover of the battery cell, and the second welding area is the second top cover of the battery cell; or; The first welding area is the first connecting piece, and the second welding area is the second connecting piece.

7. A method for manufacturing a battery cell, used to manufacture the battery cell according to any one of claims 1-6, characterized in that, include: Obtain a positive electrode plate, a negative electrode plate, and a separator, wherein the positive electrode plate includes a first positive electrode plate and a second positive electrode plate, and the negative electrode plate includes a first negative electrode plate and a second negative electrode plate; A positive electrode plate, a separator, and a negative electrode plate are stacked sequentially along the second direction, such that the first positive electrode tab in the first positive electrode plate and the first negative electrode tab in the first negative electrode plate are located at the first end of the cell in the first direction, and the second positive electrode tab in the second positive electrode plate and the second negative electrode tab in the second negative electrode plate are located at the second end of the cell in the first direction. Pre-welded multilayer first positive electrode tab, pre-welded multilayer first negative electrode tab, and pre-welded multilayer second positive electrode tab; A first welding area and a second welding area are obtained, such that the first welding area is located at the first end of the battery cell in a first direction, and the second welding area is located at the second end of the battery cell in a first direction. The pre-welded multilayer first positive electrode tab and the pre-welded multilayer first negative electrode tab are welded to the first welding area; The pre-welded multilayer second positive electrode tab and the pre-welded multilayer second negative electrode tab are welded to the second welding area.

8. A single battery cell, characterized in that, Includes a housing, a first top cover, a second top cover, and a battery cell as described in any one of claims 1-6; The first top cover is disposed at the first end of the battery cell along the first direction; The second top cover is disposed at the second end of the battery cell along the first direction; The first top cover, the second top cover, and the battery cell are all disposed inside the housing.

9. A battery pack, characterized in that, The battery pack includes one or more of the battery cells described in claim 8.

10. An electrical appliance, characterized in that, Includes the battery pack as described in claim 9, the battery pack being used to provide electrical energy.

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