Multi-tab pole piece and battery

Abstract

The utility model relates to a multi-tab pole piece and a battery. The multi-tab pole piece comprises a pole piece body, wherein a plurality of tabs are arranged on the edge of the pole piece body at intervals; an avoiding groove is formed in the edge of the pole piece body, part of the pole lug is located in the avoiding groove, one end of the pole lug is connected with the bottom of the avoiding groove, and the other end of the pole lug extends out of the avoiding groove, so that the two ends of the pole lug are located on the two sides of the edge of the pole piece body; at least the edge, located in the avoiding groove, of the tab is obliquely arranged, so that the width of the tab is gradually reduced from the bottom of the avoiding groove to the direction extending out of the avoiding groove, and the side wall of the avoiding groove is obliquely arranged and is matched with the edge of the tab. According to the scheme provided by the invention, the energy density of the battery cell can be improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a multi-electrode pole piece and a battery. Background Art

[0002] Multi-electrode soft-package lithium-ion batteries are widely used in small power equipment such as power tools and small drones. Figure 1 The figure is a schematic diagram of the structure of a multi-electrode pole piece in the related art, which includes a body 1' and a pole ear 2' provided on the body. The vertical width of the body 1' in the figure is W1. Compared with ordinary single-electrode soft-package lithium-ion batteries, the number of pole ears of multi-electrode soft-package lithium-ion batteries is generally greater than two. The common way to output the pole ears is to output the pole ears from each layer or interlayer of the winding core, and finally weld the soft pole ears and the hard pole ears on the pole piece to encapsulate them into a battery cell.

[0003] In the related art, in order to ensure the smooth progress of the packaging process, a certain space is reserved at the head of the battery cell for the folded pole ear, which will reduce the energy density of the battery cell. Utility Model Content

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a multi-pole pole piece and a battery, which can improve the energy density of the battery cell.

[0005] A first aspect of the present application provides a multi-electrode tab pole piece, comprising: a pole piece body, wherein a plurality of pole tabs are arranged at intervals on the edge of the pole piece body;

[0006] An avoidance groove is provided at the edge of the pole piece body, part of the pole ear is located in the avoidance groove, one end of the pole ear is connected to the bottom of the avoidance groove, and the other end of the pole ear extends outward from the avoidance groove, so that the two ends of the pole ear are located on both sides of the edge of the pole piece body;

[0007] At least the edge of the pole lug located in the avoidance groove is inclined so that the width of the pole lug gradually decreases from the bottom of the avoidance groove to the direction extending out of the avoidance groove, and the side wall of the avoidance groove is inclined and coincides with the edge of the pole lug.

[0008] Furthermore, the two side edges of the pole ear are inclined.

[0009] Furthermore, the pole lug is trapezoidal, and the avoidance groove is a trapezoidal shape that matches the shape of the pole lug.

[0010] Furthermore, the width of the edge of one side where the pole ear is connected to the avoidance groove is greater than or equal to 8 mm.

[0011] Furthermore, the angle between the inclined edge of the pole ear and the bottom of the avoidance groove is α, 60°≤α<90°.

[0012] Furthermore, the tab is provided with a rounded corner, and the size of the rounded corner is R1.

[0013] Furthermore, the distance from the bottom of the avoidance groove to the edge of the pole piece body is 1-2 mm.

[0014] Furthermore, the pole ear and the pole piece body are an integrally formed structure.

[0015] A second aspect of the present application provides a battery, comprising: a multi-pole tab pole piece as described in any one of the above items and an active material layer provided on the surface of the multi-pole tab pole piece.

[0016] Furthermore, the battery has a positive electrode sheet and a negative electrode sheet, and both the positive electrode sheet and the negative electrode sheet are made of the multi-pole tab electrode sheet.

[0017] The technical solution provided by the present application may include the following beneficial effects: by setting an avoidance groove on the edge of the pole piece body, one end of the pole ear is connected to the bottom of the avoidance groove, and the other end of the pole ear extends outward from the avoidance groove, so that the two ends of the pole ear are located on both sides of the edge of the pole piece body, and at least the edge of the pole ear located in the avoidance groove is inclined, so that the width of the pole ear gradually decreases from the bottom of the avoidance groove to the direction in which the avoidance groove extends, and the side wall of the avoidance groove is inclined and coincides with the edge of the pole ear. In this way, the area of ​​the pole piece body can be expanded compared with the related technology while the width of the connection between the pole ear and the pole piece body remains unchanged, thereby increasing the carrying capacity of the pole piece body for active substances, and further increasing the energy density of the battery cell.

[0018] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent by describing in more detail exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0020] Figure 1 It is a schematic diagram of the structure of a multi-electrode pole piece shown in the related art;

[0021] Figure 2 is a schematic diagram of the structure of a multi-electrode pole piece shown in an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of the structure of a multi-electrode pole piece at the pole ear shown in an embodiment of the present application;

[0023] Figure 4 is a schematic diagram of the structure of a multi-electrode pole piece at the pole ear shown in another embodiment of the present application;

[0024] Figure 5 is a schematic diagram of the structure of a multi-electrode pole piece at the pole ear shown in another embodiment of the present application;

[0025] Figure 6 It is a schematic diagram of the structure of the winding core shown in the embodiment of the present application.

[0026] Reference numerals:

[0027] 1'-main body, 2'-ear, 1-pole body, 2-ear, 3-avoidance groove. DETAILED DESCRIPTION

[0028] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0029] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0030] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0031] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] Figure 1 The figure is a schematic diagram of the structure of a multi-electrode tab in the related art. The multi-electrode tab includes a body 1' and a tab 2' arranged on the body. The width of the body 1' in the vertical direction is W1. In the related art, in order to smoothly carry out the packaging process, a certain space is reserved for the folded tab at the head of the battery cell, that is, Figure 1 A certain space is reserved above the upper edge of the middle body 1' for the folded tab, which will reduce the energy density of the battery cell.

[0033] In view of the above problems, the embodiments of the present application provide a multi-electrode pole piece and a battery, which can improve the energy density of the battery cell.

[0034] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0035] like Figure 2 and Figure 3 As shown, the embodiment of the present application provides a multi-ear pole piece, including a pole piece body 1, and a plurality of pole ears 2 are arranged at intervals on the edge of the pole piece body 1. In the figure, the plurality of pole ears 2 are arranged at intervals on the upper edge of the pole piece body 1, the width of the pole piece body 1 in the vertical direction is W1+W2, the lower end of the pole ear 2 is connected to the pole piece body 1, and the width of the connection between the lower end of the pole ear 2 and the pole piece body 1 is W.

[0036] The edge of the pole piece body 1 is provided with an avoidance groove 3, part of the pole ear 2 is located in the avoidance groove 3, one end of the pole ear 2 is connected to the bottom of the avoidance groove 3, and the other end of the pole ear 2 extends out of the avoidance groove 3, so that the two ends of the pole ear 2 are located on both sides of the edge of the pole piece body 1. Specifically, the upper edge of the pole piece body 1 is provided with an avoidance groove 3, the lower part of the pole ear 2 is located in the avoidance groove 3, and the upper part is located outside the avoidance groove 3, the lower end of the pole ear 2 is connected to the bottom edge of the avoidance groove 3, and the upper end of the pole ear 2 extends upward out of the avoidance groove 3, so that the upper end of the pole ear 2 is located above the upper edge of the pole piece body 1, and the lower end of the pole ear 2 is located below the upper edge of the pole piece body 1.

[0037] Among them, at least the edge of the pole ear 2 located in the avoidance groove 3 is inclined, so that the width of the pole ear 2 gradually decreases from the bottom of the avoidance groove 3 to the direction extending out of the avoidance groove 3, that is, at least the edge of the pole ear 2 located in the avoidance groove 3 is inclined upward and toward the middle of the pole ear 2, and the inclined edge makes the width of the pole ear 2 in the horizontal direction gradually decrease from bottom to top.

[0038] The side wall of the avoidance groove 3 is inclined and coincides with the edge of the pole lug 2, that is, in the figure, the side wall of the avoidance groove 3 is inclined from bottom to top toward the pole lug 2, and the side of the avoidance groove 3 is a triangle. The avoidance groove 3 can be formed on the pole piece body 1 by cutting.

[0039] Figure 2 In the embodiment, the width W2 of the upper edge of the pole body 1 is the reserved width of the folded pole ear, and the pole ear 2 can be bent within the width range of W2. In this way, when making batteries of the same model, compared with the body 1' in the related art, Figure 2 The width W1+W2 of the pole piece body 1 is Figure 1 The width W1 of the middle body 1' is larger than W2. The surface of the pole piece body 1 is coated with active material. Figure 1 In the body 1', the area where the pole piece body 1 can be coated exceeds the area corresponding to W2.

[0040] The side wall of the avoidance groove 3 is inclined toward the pole ear 2, so that the coating area of ​​the pole piece body 1 is further expanded. Because the width W at the connection between the pole ear 2 and the pole piece body 1 remains unchanged, the area of ​​the avoidance groove 3 with the inclined side wall is larger relative to the vertical extension of the side wall. At the same time, the unchanged width W can ensure the connection strength between the pole ear 2 and the pole piece body 1.

[0041] By setting an avoidance groove 3 on the edge of the pole piece body 1, one end of the pole ear 2 is connected to the bottom of the avoidance groove 3, and the other end of the pole ear 2 extends outward from the avoidance groove 3, so that the two ends of the pole ear 2 are located on both sides of the edge of the pole piece body 1, and at least the edge of the pole ear 2 located in the avoidance groove 3 is inclined, so that the width of the pole ear 2 gradually decreases from the bottom of the avoidance groove 3 to the direction extending from the avoidance groove 3, and the side wall of the avoidance groove 3 is inclined and coincides with the edge of the pole ear 2. In this way, compared with the related technology, the area of ​​the pole piece body 1 can be expanded while the width W at the connection between the pole ear 2 and the pole piece body 1 remains unchanged and the connection strength is guaranteed, thereby increasing the carrying capacity of the pole piece body 1 for active substances, thereby increasing the energy density of the battery cell.

[0042] In some embodiments, Figure 2 and Figure 3As shown, the two side edges of the pole lug 2 are respectively inclined, and correspondingly, the two side walls of the avoidance groove 3 are also inclined. The two side edges of the pole lug 2 are respectively inclined, which can further increase the area of ​​the pole piece body 1 compared with the inclined setting of one side edge, thereby increasing the carrying capacity of the pole piece body 1 for the active material. In other embodiments, the pole lug 2 can also be set to be inclined on only one side edge. The inclination of the side edge of the pole lug 2 can be set so that the entire side is inclined, or only the part of the side located in the avoidance groove 3 is set to be inclined, and the part of the side located outside the avoidance groove 3 is set to be vertical.

[0043] In some embodiments, Figure 2 and Figure 3 As shown, the pole lug 2 is a trapezoid, and the avoidance groove 3 is a trapezoid that matches the shape of the pole lug 2. Specifically, the upper bottom of the pole lug 2 is located outside the avoidance groove 3, that is, located above the upper edge of the pole piece body 1, and the lower bottom of the pole lug 2 is connected to the bottom of the avoidance groove 3. The two waists of the pole lug 2 extend obliquely, the avoidance groove 3 matches the shape of the pole lug 2, and the upper end of the avoidance groove 3 is open.

[0044] In some embodiments, the width W of the edge of one side where the pole ear 2 is connected to the avoidance groove 3 is greater than or equal to 8 mm, which can ensure the connection strength between the pole ear 2 and the pole piece body 1. If W is too small, the effect of improving the energy density of the battery cell is not obvious, and the connection strength between the pole ear 2 and the pole piece body 1 will be weakened.

[0045] In some embodiments, the angle between the inclined edge of the tab 2 and the bottom of the avoidance groove 3 is α, 60°≤α<90°. The maximum value of α can be infinitely close to 90°, but the energy density is also small at this time; if the value of α is too small, it will affect the welding of the tab sheet (hard tab) on the upper part of the tab 2, so α≥60° ​​is a more suitable range. Preferably, 60°≤α<80°.

[0046] like Figure 4 As shown, this embodiment shows a schematic diagram of the structure of another multi-ear pole piece at the ear 2, wherein α=80°, the side of the avoidance groove 3 is tilted toward the ear 2, the extra area is smaller, and the area of ​​the ear 2 is larger, which is beneficial to the connection and bending of the ear 2.

[0047] like Figure 5 As shown, this embodiment shows a schematic diagram of the structure of another multi-ear pole piece at the ear 2, wherein α=60°, the side of the avoidance groove 3 is inclined toward the ear 2 with a larger area, and the area of ​​the ear 2 is smaller, which is beneficial to increase the coating area of ​​the pole piece body 1.

[0048] In some embodiments, Figure 3As shown, the tab 2 is provided with a rounded corner, and the size of the rounded corner is R1, that is, the radius of the rounded corner R1 in the figure is 2 mm. Specifically, the tab 2 is a trapezoidal structure, and the two corners at both ends of the upper bottom of the tab 2 are set as the rounded corners R1, and the center of the rounded corner R1 is located inside the tab 2. The two corners at both ends of the lower bottom of the tab 2 can also be provided with rounded corners, and the center of the rounded corner is located outside the tab 2.

[0049] In some embodiments, the distance from the bottom of the avoidance groove 3 to the edge of the pole piece body 1 is 1-2 mm, that is, Figure 2 The middle W2 is 1-2mm. This distance range can ensure the space for folding the pole ears. If it is too small, there will not be enough space for folding the pole ears. If it is too large, it will affect the size of the battery cell.

[0050] In some embodiments, the pole lug 2 and the pole piece body 1 are an integrally formed structure. Specifically, the pole lug 2 and the pole piece body 1 can be formed by cutting, for example, by die cutting or laser cutting, to form the pole lug 2, the avoidance groove 3 and the pole piece body 1.

[0051] The embodiments of the present application also provide a battery, including the multi-pole ear pole piece described in the above embodiments and an active material layer arranged on the surface of the multi-pole ear pole piece. For example, the active material layer coated on the multi-pole ear pole piece as the positive electrode piece may be lithium cobalt oxide (LCO), lithium iron phosphate (LFP) or a ternary material (such as lithium nickel cobalt manganese oxide NCM or lithium nickel cobalt aluminum oxide NCA), which release lithium ions during charging and absorb lithium ions during discharging, thereby realizing the storage and release of electrical energy. The active material layer coated on the multi-pole ear pole piece as the negative electrode piece may be graphite, which has excellent electrochemical properties and can reversibly deintercalate lithium ions and store energy. In addition to graphite, the negative electrode active material may also include other carbon-based materials, such as hard carbon, soft carbon and graphene.

[0052] In addition to active materials, multi-electrode tab coatings also include other components such as conductive agents and binders. Conductive agents are used to improve the conductivity of electrodes and ensure smooth transmission of current inside the battery; while binders are used to firmly bond active materials, conductive agents and electrode current collectors together to form a stable electrode structure.

[0053] In some embodiments, the battery has a positive electrode sheet and a negative electrode sheet, and both the positive electrode sheet and the negative electrode sheet are made of the above-mentioned multi-electrode ear electrode sheet. Specifically, the commonly used method of outputting the electrode ear of the multi-electrode soft-package lithium-ion battery is to output the electrode ear from each layer or interlayer of the winding core, and finally weld the soft electrode ear and the hard electrode ear to encapsulate into a battery cell. There is also a diaphragm between two adjacent electrode sheets. The winding core obtained by winding the multi-electrode ear electrode sheet and the diaphragm is as follows Figure 6 As shown, the core is subjected to transfer welding, packaging, liquid injection and other processes to obtain a battery cell.

[0054] The battery provided in the embodiment of the present application adopts the multi-electrode ear pole piece described in the above embodiment, which can increase the carrying capacity of the pole piece body 1 for active materials, thereby improving the energy density of the battery cell.

[0055] The embodiment of the present application also provides a specific battery example. The prepared battery model is 904290. 50 pcs of battery cells are prepared according to the multi-pole ear pole piece design of the related art and the multi-pole ear pole piece design provided in the embodiment of the present application. The reserved folded ear width in the multi-pole ear pole piece provided in the embodiment of the present application is 1.5mm, that is, W2=1.5mm in the design. The energy density of the two groups of battery cells prepared were tested respectively. The average energy density of the battery cells using the multi-pole ear pole piece of the related art is 579.5Wh / L (0.2C), and the average energy density of the battery using the multi-pole ear pole piece provided in the embodiment of the present application is 600.2Wh / L (0.2C). It can be seen that the average energy density of the battery using the multi-pole ear pole piece provided in the embodiment of the present application has been significantly improved.

[0056] The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of the various embodiments have their own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Those skilled in the art should also be aware that the actions and modules involved in the specification are not necessarily required for the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application can be adjusted in order, merged and deleted according to actual needs, and the modules in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0057] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A multi-electrode pole piece, characterized in that: include: A pole piece body, wherein a plurality of pole ears are arranged at intervals on the edge of the pole piece body; An avoidance groove is provided at the edge of the pole piece body, part of the pole ear is located in the avoidance groove, one end of the pole ear is connected to the bottom of the avoidance groove, and the other end of the pole ear extends outward from the avoidance groove, so that the two ends of the pole ear are located on both sides of the edge of the pole piece body; At least the edge of the pole lug located in the avoidance groove is inclined so that the width of the pole lug gradually decreases from the bottom of the avoidance groove to the direction extending out of the avoidance groove, and the side wall of the avoidance groove is inclined and coincides with the edge of the pole lug.

2. The multi-electrode pole piece according to claim 1, characterized in that: The two side edges of the pole ear are respectively inclined.

3. The multi-electrode pole piece according to claim 1, characterized in that: The pole lug is in a trapezoidal shape, and the avoidance groove is in a trapezoidal shape that matches the shape of the pole lug.

4. The multi-electrode pole piece according to claim 1, characterized in that: The width of the edge of one side where the pole ear is connected to the avoidance groove is greater than or equal to 8 mm.

5. The multi-electrode pole piece according to claim 1, characterized in that: The angle between the inclined edge of the pole ear and the bottom of the avoidance groove is α, and 60°≤α<90°.

6. The multi-electrode pole piece according to claim 1, characterized in that: The tab is provided with a rounded corner, and the size of the rounded corner is R1.

7. The multi-electrode pole piece according to claim 1, characterized in that: The distance from the bottom of the avoidance groove to the edge of the pole piece body is 1-2 mm.

8. The multi-electrode pole piece according to claim 1, characterized in that: The pole ear and the pole piece body are an integrally formed structure.

9. A battery, characterized in that: include: A multi-electrode pole piece as described in any one of claims 1 to 8 and an active material layer provided on the surface of the multi-electrode pole piece.

10. The battery according to claim 9, characterized in that: The battery comprises a positive electrode sheet and a negative electrode sheet, and both the positive electrode sheet and the negative electrode sheet are made of the multi-electrode tab electrode sheet.

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