Battery pole piece, battery cell, battery and electric equipment

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery pole piece, a battery cell, a battery and electric equipment, the battery pole piece comprises a pole piece body and a conductive piece, the pole piece body is provided with a first square area, the first square area is provided with a groove, the bottom wall of the groove is provided with a first area, and the conductive piece is provided with a first connecting part and a second connecting part. The first connecting part is welded to the first area, the first connecting part is provided with a second area, and a welding mark structure is formed on the second area; the orthographic projection area of the groove on the pole piece body is smaller than that of the first square region on the pole piece body; the orthographic projection area of the welding printing structure on the pole piece body is larger than that of the second region on the pole piece body; the orthographic projection area of the groove is effectively reduced, and the energy density of the battery cell is improved; the area of the welding and printing structure is effectively increased, and the heat produced by the tab is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of battery, concretely relates to battery pole piece, electric core, battery and electric equipment. BACKGROUND

[0002] Lithium ion battery as a new type of secondary battery has the advantages of high energy density and power density, high working voltage, light weight, small size, long cycle life, good safety, green environmental protection and the like, and has broad application prospects in portable electric appliances, electric tools, large energy storage, electric transportation power supply and the like.

[0003] In the prior art, the tab is generally welded with the groove of the battery pole piece, and the shapes of the groove and the tab are both designed in square. This design connects the tab and the groove through square three-point welding technology, and then square protective glue is pasted on the tab position and the consistent pole piece. However, this design leads to low space utilization of the active material layer, thereby affecting the energy density of the electric core. In addition, the welding mark area of the square tab is relatively small, which will cause high heat at the tab position during the charging and discharging process. SUMMARY

[0004] The utility model discloses to the technical problem of the prior art, provide a kind of battery pole piece, electric core, battery and electric equipment, solve the technical problem that the space utilization of active material layer is low in the prior art square tab and groove design, affect the energy density of electric core, and small welding mark area is prone to cause high heat at tab position when charging and discharging.

[0005] To achieve the above object, the utility model adopts the following technical scheme:

[0006] Firstly, the utility model provides a kind of battery pole piece, including pole piece body and conducting piece, the first square area is provided with groove on the pole piece body, the bottom wall of the groove has first area, the conducting piece has first connecting portion and second connecting portion, the first connecting portion is welded in the first area, the first connecting portion has second area, the second area is formed with welding mark structure, the second connecting portion extends from one end of the first connecting portion to the outside of the groove;

[0007] When the first connecting part is smaller than the first area in the projection area on the pole piece body, the projection area of the groove on the pole piece body is smaller than the projection area of the first square area on the pole piece body; when the projection area of the groove on the pole piece body is equal to the projection area of the first square area on the pole piece body, the projection area of the welding structure on the pole piece body is greater than the projection area of the second area on the pole piece body.

[0008] In some embodiments, the first connecting part is consistent with the projection shape of the welding structure;

[0009] And / or, when the projection of the groove on the pole piece body is circular or elliptical, the shape of the projection of the first connecting part is consistent with the shape of the projection of the groove.

[0010] In some embodiments, the pole piece body further has a second square area, the first square area is located in the second square area, the second square area is provided with an insulating layer, the insulating layer covers the groove, and the projection area of the insulating layer on the pole piece body is smaller than or equal to the projection area of the second square area on the pole piece body along the thickness direction of the pole piece body.

[0011] In some embodiments, the projection shape of the insulating layer is consistent with the projection shape of the groove;

[0012] And / or, the projection shape of the insulating layer is consistent with the projection shape of the first connecting part;

[0013] And / or, the projection shape of the insulating layer is consistent with the projection shape of the welding structure.

[0014] In some embodiments, the projection shape of the groove is square, circular, elliptical, trapezoidal, hexagonal, octagonal or special-shaped;

[0015] And / or, the projection shape of the first connecting part is circular, elliptical, trapezoidal, hexagonal, octagonal or special-shaped;

[0016] And / or, the projection shape of the welding structure is circular, elliptical, trapezoidal, hexagonal, octagonal or special-shaped;

[0017] And / or, the projection shape of the insulating layer is square, circular, elliptical, trapezoidal, hexagonal, octagonal or special-shaped.

[0018] In some embodiments, the welding structure is provided with one or more.

[0019] In some embodiments, the pole piece body comprises a current collector and an active material layer, the active material layer is arranged on at least one surface of the current collector, along the length direction of the current collector, the first square area and the groove are both arranged in the middle part of the active material layer, and the bottom wall of the groove is the current collector.

[0020] In a second aspect, the utility model provides a kind of battery cell, comprising first pole piece, second pole piece and diaphragm being arranged between the first pole piece and the second pole piece, the first pole piece, the diaphragm and the second pole piece are stacked and are wound to form battery cell, and the first pole piece and / or the second pole piece are the battery pole piece of above-mentioned embodiment.

[0021] In a third aspect, the utility model provides a kind of battery, comprising the battery cell of above-mentioned embodiment.

[0022] In a fourth aspect, the utility model provides a kind of electric equipment, comprising the battery of above-mentioned embodiment.

[0023] Compared with prior art, the utility model obtains the beneficial effect that:

[0024] The battery pole piece of the utility model, by the cooperation of pole piece body and conductive piece, the pole piece body has first square area, the first square area is provided with groove, the first connecting portion of conductive piece is used for being welded with the first area of groove, and the welding mark structure is formed on the second area of first connecting portion, effectively realize the electrical connection of pole piece body and conductive piece.When the orthographic projection area of first connecting portion is less than the orthographic projection area of first area, the orthographic projection area of groove is less than the orthographic projection area of first square area, compared with the existing square design, under the condition of ensuring enough welding mark area, effectively reduce the orthographic projection area of groove, can realize more compact layout, thereby improve the energy density of battery cell.When the orthographic projection area of groove is equal to the orthographic projection area of first square area, the orthographic projection area of welding mark structure is greater than the orthographic projection area of second area, compared with the existing square design, effectively increase the orthographic projection area of welding mark structure, thereby increase the welding area of first connecting portion and groove.This not only enhances the connection strength between conductive piece and pole piece body, also significantly reduces the heat generated in the position of tab in the process of charging and discharging, thereby improves the safety and stability of battery.

[0025] Additional aspects and advantages of the utility model will be in part apparent and in part pointed out hereinafter in the description. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0027] Figure 1 It is a structural schematic diagram of prior art battery pole piece.

[0028] Figure 2 It is a structural schematic diagram of the battery pole piece of the present application.

[0029] Figure 3 It is a structural schematic diagram of the battery pole piece of the present application.

[0030] Figure 4 It is a structural schematic diagram of the battery pole piece of the present application.

[0031] Figure 5 It is a structural schematic diagram of the battery pole piece of the present application.

[0032] Figure 6 It is a structural schematic diagram of the battery pole piece of the present application.

[0033] Figure 7 It is a structural schematic diagram of the pole piece body of the present application.

[0034] Figure 8 It is a structural schematic diagram of the conductive part of the present application.

[0035] Among them, the following is the explanation of the reference signs:

[0036] 100, battery pole piece;

[0037] 10, pole piece body; 11, current collector; 12, active material layer; 13, first square area; 131, groove; 1311, first area; 14, second square area;

[0038] 20, conductive part; 21, first connecting part; 211, second area; 22, second connecting part;

[0039] 30, welding structure;

[0040] 40, insulating layer;

[0041] a, along the thickness direction of the pole piece body; b, along the length direction of the current collector. DETAILED DESCRIPTION

[0042] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0043] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be interpreted as indicating or implying relative importance.

[0044] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0045] The following will be combined with the appendix Figures 1-8 The technical solutions in the embodiments of this utility model are clearly and completely described. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0046] The electrical equipment described in this utility model embodiment includes a battery. The electrical equipment can be automobiles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Automobiles can be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application embodiment does not impose any special limitations on the above-mentioned electrical equipment.

[0047] The battery of this utility model embodiment includes a battery cell, and the battery cell includes battery electrode 100.

[0048] Referring to Figures 2-8 The utility model discloses a battery pole piece 100, including pole piece body 10 and conducting part 20, first square area 13 has on pole piece body 10, the recess 131 is provided with on first square area 13, the bottom wall of recess 131 has first area 1311, conducting part 20 has first connecting portion 21 and second connecting portion 22, first connecting portion 21 is welded in first area 1311, first connecting portion 21 has second area 211, and the welding mark structure 30 is formed on second area 211, and second connecting portion 22 extends from one end of first connecting portion 21 to recess 131 outside;

[0049] Wherein, along the thickness direction a of pole piece body 10, when the first connecting portion 21 is in the first area 1311 on the pole piece body 10 on the area of orthographic projection is less than the first square area 13 in the pole piece body 10 on the area of orthographic projection, the recess 131 in the first square area 13 on the pole piece body 10 on the area of orthographic projection is less than the first square area 1311 in the pole piece body 10 on the area of orthographic projection, when the recess 131 in the first square area 13 on the pole piece body 10 on the area of orthographic projection is equal to the first square area 1311 in the pole piece body 10 on the area of orthographic projection, the welding mark structure 30 in the first square area 13 on the pole piece body 10 on the area of orthographic projection is greater than the second area 211 in the pole piece body 10 on the area of orthographic projection.

[0050] Compared with the prior art, the utility model discloses a battery pole piece 100, by the cooperation of pole piece body 10 and conducting part 20, pole piece body 10 has first square area 13, first square area 13 is provided with recess 131, and the first connecting portion 21 of conducting part 20 is used for welding with the first area 1311 of recess 131, and forms the welding mark structure 30 on the second area 211 of first connecting portion 21, effectively realizes the electric connection of pole piece body 10 and conducting part 20. When the orthographic projection area of first connecting portion 21 is less than the orthographic projection area of first area 1311, the orthographic projection area of recess 131 is less than the orthographic projection area of first square area 13, compared with the existing square design, effectively reduces the orthographic projection area of recess 131 under the condition of ensuring enough welding mark area, can realize more compact layout, thereby improve the energy density of electric core. When the orthographic projection area of recess 131 is equal to the orthographic projection area of first square area 13, the orthographic projection area of welding mark structure 30 is greater than the orthographic projection area of second area 211, compared with the existing square design, effectively increases the orthographic projection area of welding mark structure 30, thereby increases the welding area of first connecting portion 21 and recess 131. This not only enhances the connecting strength between conducting part 20 and pole piece body 10, but also significantly reduces the heat generated at the position of tab in the charging and discharging process, thereby improves the safety and stability of battery.

[0051] It can be understood that the first square area 13, the first area 1311 and the second area 211 are all preset areas.

[0052] In some embodiments, the area of the front projection of the welding structure 30 accounts for 50% to 100% of the area of the front projection of the first connecting part 21. By setting the area of the front projection of the welding structure 30, when the area of the front projection of the welding structure 30 accounts for less than 50% of the area of the front projection of the first connecting part 21, the area of the front projection of the welding structure 30 is small, which leads to an increase in contact resistance, and more heat is generated when the current passes through the welding structure 30, which not only increases energy loss, but also may affect the performance and life of the battery. At the same time, the contact area between the first connecting part 21 of the conductive part 20 and the groove 131 is small, which leads to insufficient connection strength between the conductive part 20 and the pole piece body 10, and the conductive part 20 may be loose or broken. Therefore, the area of the front projection of the welding structure 30 accounts for 50% to 100% of the area of the front projection of the first connecting part 21. The area of the front projection of the welding structure 30 is effectively increased, thereby increasing the welding area of the first connecting part 21 and the groove 131. Not only does it enhance the connection strength between the conductive part 20 and the pole piece body 10, but it also significantly reduces the heat generated at the tab position during the charging and discharging process, thereby improving the safety and stability of the battery.

[0053] Specifically, the area of the front projection of the welding structure 30 accounts for 50%, 52%, 55%, 58%, 60%, 61%, 63%, 65%, 70%, 75%, 77%, 79%, 80%, 82%, 85%, 88%, 90%, 94%, 95%, 96%, 99% or 100% of the area of the front projection of the first connecting part 21, but is not limited to the listed values, and other values within the value range are also applicable.

[0054] Please refer to Figures 2-6 In some embodiments, the front projection shape of the first connecting part 21 is consistent with the front projection shape of the welding structure 30. By making the front projection shapes of the first connecting part 21 and the welding structure 30 consistent, the accuracy of the alignment of the two during welding is improved, the welding deviation is reduced, and the precision of the welding is improved. This consistency design also helps to form a larger and more uniform welding contact surface, thereby enhancing the connection strength of the first connecting part 21 and the groove 131 and improving the overall structural stability of the battery pole piece 100.

[0055] And / or, when the orthogonal projection of the groove 131 on the pole piece body 10 is circular or elliptical, the shape of the orthogonal projection of the first connecting part 21 is consistent with the shape of the orthogonal projection of the groove 131. By making the orthogonal projection shape of the groove 131 consistent with the first connecting part 21, the groove 131 and the first connecting part 21 can better adapt to the layout requirements of the battery pole piece 100, improve the space utilization of the battery pole piece 100, and thus improve the energy density of the battery cell.

[0056] Please refer to Figure 2 And Figures 5-8 In some embodiments, the pole piece body 10 also has a second square area 14, the first square area 13 is located in the second square area 14, and the second square area 14 is provided with an insulating layer 40 covering the groove 131. The orthogonal projection area of the insulating layer 40 on the pole piece body 10 is less than or equal to the orthogonal projection area of the second square area 14 on the pole piece body 10 along the thickness direction a of the pole piece body 10. By setting the insulating layer 40, the insulating layer 40 is set on the pole piece body 10 and covers the groove 131, effectively isolating the groove 131 and the conductive structure (such as the welding mark structure 30 and the first connecting part 21) inside from direct contact with the active material layer 12, thereby enhancing the electrical isolation performance and overall safety of the battery. This helps to prevent safety hazards such as short circuit and leakage, ensuring the safety and stability of the battery. In addition, the orthogonal projection area of the insulating layer 40 is less than or equal to the orthogonal projection area of the second square area 14, effectively ensuring the covering effect of the insulating layer 40 on the groove 131. And when the orthogonal projection area of the insulating layer 40 is less than the orthogonal projection area of the second square area 14, it means that the insulating layer 40 occupies less space on the pole piece body 10 within the same battery volume, and less insulating material is required. Not only can the use of insulating material of the insulating layer 40 be saved, but also the weight of the battery cell can be reduced, and the energy density of the battery cell can be improved.

[0057] In some embodiments, the orthogonal projection shape of the insulating layer 40 is consistent with the orthogonal projection shape of the groove 131. The consistency of the shape of the insulating layer 40 and the groove 131 ensures that the insulating layer 40 can accurately cover the groove 131 area, effectively avoiding the exposure of the first connecting part 21 and the welding mark structure 30 in the groove 131, which can cause the first connecting part 21 and the welding mark structure 30 to contact the active material layer 12 and cause the battery cell to short circuit. At the same time, it can also maximize the use of space and reduce unnecessary material waste.

[0058] And / or, the shape of the orthogonal projection of the insulating layer 40 is consistent with the shape of the orthogonal projection of the first connecting part 21. The shape consistency of the insulating layer 40 and the first connecting part 21 provides a clear visual identification for the battery pole piece 100, effectively making the pasting of the insulating layer 40 more intuitive and simple. In the automatic production line, such design helps to achieve more accurate pasting positioning, reducing the risk of poor insulation or electrical short circuit caused by position deviation. At the same time, in manual operation, the staff can also more easily and accurately paste the insulating layer 40 to the first connecting part 21, improving work efficiency and product quality.

[0059] And / or, the shape of the orthogonal projection of the insulating layer 40 is consistent with the shape of the orthogonal projection of the welding mark structure 30. The shape consistency of the insulating layer 40 and the welding mark structure 30 provides a clear visual identification for the battery pole piece 100, effectively making the pasting of the insulating layer 40 more intuitive and simple. In the automatic production line, such design helps to achieve more accurate pasting positioning, reducing the risk of poor insulation or electrical short circuit caused by position deviation. At the same time, in manual operation, the staff can also more easily and accurately paste the insulating layer 40 to the first connecting part 21, improving work efficiency and product quality.

[0060] In some embodiments, the orthogonal projection shape of the groove 131 is square, circular, elliptical, trapezoidal, hexagonal, octagonal or irregular; and / or, the orthogonal projection shape of the first connecting part 21 is circular, elliptical, trapezoidal, hexagonal, octagonal or irregular; and / or, the orthogonal projection shape of the welding mark structure 30 is circular, elliptical, trapezoidal, hexagonal, octagonal or irregular; and / or, the orthogonal projection shape of the insulating layer 40 is square, circular, elliptical, trapezoidal, hexagonal, octagonal or irregular. Through the above setting, the diversification of the orthogonal projection shape of the groove 131, the orthogonal projection shape of the first connecting part 21, the orthogonal projection shape of the welding mark structure 30 and the orthogonal projection shape of the insulating layer 40 is effectively increased, and appropriate groove 131, first connecting part 21, welding mark structure 30 and insulating layer 40 shape can be selected according to actual needs to meet the space limitation and performance requirement.

[0061] Specifically, the orthogonal projection area of the first square area 13 is S5, when the orthogonal projection shape of the groove 131 is circular, elliptical, trapezoidal, hexagonal, octagonal or irregular, the orthogonal projection area of the groove 131 is T1, and when the orthogonal projection shape of the groove 131 is square, the orthogonal projection area of the groove 131 is T2. Wherein, T1

[0062] It can be understood that the above-mentioned special shape refers to a non-standard, irregular or unconventional shape. Compared with the above-mentioned several shapes with clear geometric characteristics (such as square, circular, elliptical, trapezoidal, hexagonal or octagonal), the orthographic projection of the special-shaped groove 131 does not have these standard shape characteristics.

[0063] In some embodiments, the pole piece body 10 includes a current collector 11 and an active material layer 12, the active material layer 12 is arranged on at least one surface of the current collector 11, along the length direction b of the current collector 11, the first square area 13 and the groove 131 are both arranged in the middle part of the active material layer 12, and the bottom wall of the groove 131 is the current collector 11. Through the cooperation of the current collector 11 and the active material layer 12, the first square area 13 and the groove 131 are both arranged in the middle part of the active material layer 12, which effectively enables the conductive part 20 to be arranged at the center position of the battery cell, and more effectively reduces the transmission distance of the current inside the battery, thereby reducing the resistance and improving the current transmission efficiency. In addition, since the tab is centrally arranged, the internal resistance of the battery is reduced, which enables the battery to receive and store electrical energy faster during fast charging, thereby improving the fast charging performance. At the same time, reducing the internal resistance also helps to reduce the heat generation of the battery during charging and discharging, prolonging the cycle life of the battery.

[0064] In some embodiments, the welding structure 30 is provided with one or more. Through the arrangement of one or more welding structures 30, the connection strength of the first connecting part 21 and the groove 131 is effectively enhanced, and the overall structural stability of the battery pole piece 100 is improved.

[0065] The battery cell of the embodiment of the utility model, including first pole piece, second pole piece and diaphragm between first pole piece and second pole piece, first pole piece, diaphragm and second pole piece are stacked and wound to form battery cell, first pole piece and / or second pole piece are battery pole piece 100 of above-mentioned embodiment.

[0066] The performance of the battery pole piece 100 provided by the utility model is described below through specific examples and comparative examples.

[0067] Comparative Example 1:

[0068] Please refer to Figure 1 , the battery pole piece 100 includes a pole piece body 10 and a conductive part 20, the pole piece body 10 is provided with a groove 131, one end of the conductive part 20 is welded in the groove 131, a welding structure 30 is formed on one end of the conductive part 20, and the orthographic projection of the groove 131, the welding structure 30 and the part of the conductive part 20 welded with the groove 131 on the pole piece body 10 is square along the thickness direction a of the pole piece body 10.

[0069] The orthographic projection area of the groove 131 is S1, S1 = 240mm 2;

[0070] The normal projection area of the welding mark structure 30 is S2, S2 = 36 mm 2 ;

[0071] The distance between the edge of the groove 131 and the edge of the conductive piece 20 is Y1, Y1 = 2 mm;

[0072] The distance Y2 between the edge of the conductive piece 20 and the edge of the welding mark structure 30, Y2 = 1.5 mm;

[0073] The internal resistance R1 of the welding mark structure 30 satisfies the relationship: Wherein, p is the resistivity of the conductive piece 20, and H is the thickness of the conductive piece 20.

[0074] Example 1:

[0075] Please refer to Figures 4-8 , the battery pole piece 100 includes a pole piece body 10 and a conductive piece 20, the pole piece body 10 has a first square area 13, the first square area 13 is provided with a groove 131, the bottom wall of the groove 131 has a first area 1311, the conductive piece 20 has a first connecting part 21 and a second connecting part 22, the first connecting part 21 is welded on the first area 1311, the first connecting part 21 has a second area 211, the second area 211 is formed with a welding mark structure 30, and the second connecting part 22 extends from one end of the first connecting part 21 to outside the groove 131; wherein, the thickness direction a of the pole piece body 10, when the normal projection area of the first connecting part 21 on the pole piece body 10 is less than the normal projection area of the first area 1311 on the pole piece body 10, the normal projection area of the groove 131 on the pole piece body 10 is less than the normal projection area of the first square area 13 on the pole piece body 10, and the normal projection of the groove 131, the first connecting part 21 and the welding mark structure 30 on the pole piece body 10 is circular.

[0076] The normal projection area of the first square area 13 is S5, S5 = 240 mm 2 ;

[0077] The normal projection area of the welding mark structure 30 is S2, S2 = 36 mm 2 ;

[0078] The distance between the edge of the groove 131 and the edge of the conductive piece 20 is Y1, Y1 = 2 mm;

[0079] The distance Y2 between the edge of the conductive piece 20 and the edge of the welding mark structure 30, Y2 = 1.5 mm.

[0080] According to the data of the present embodiment, it can be calculated that:

[0081] The radius R3 of the welding mark structure 30,

[0082] The radius of groove 131 is R4, R4 = R3 + Y1 + Y2 = 3.385 + 2 + 1.5 = 6.885 mm;

[0083] The projected area of ​​groove 131 is S3, where S3 = π(R4). 2 =3.14 × 6.885 2 ≈148.846mm 2 .

[0084] Example 2:

[0085] Please see Figures 4-8 The battery electrode 100 includes an electrode body 10 and a conductive element 20. The electrode body 10 has a first square region 13, and a groove 131 is provided on the first square region 13. The bottom wall of the groove 131 has a first region 1311. The conductive element 20 has a first connecting portion 21 and a second connecting portion 22. The first connecting portion 21 is welded to the first region 1311. The first connecting portion 21 has a second region 211, and a solder structure 30 is formed on the second region 211. The second connecting portion 22 extends from one end of the first connecting portion 21 to the outside of the groove 131. The thickness direction of the electrode body 10 is aa. When the orthographic projection area of ​​the groove 131 on the electrode body 10 is equal to the orthographic projection area of ​​the first square region 13 on the electrode body 10, the orthographic projection area of ​​the solder structure 30 on the electrode body 10 is greater than the orthographic projection area of ​​the second region 211 on the electrode body 10. The orthographic projections of the groove 131, the first connecting portion 21, and the solder structure 30 on the electrode body 10 are all circular.

[0086] The orthographic projection area of ​​the first square region 13 is S5, where S5 = 240 mm. 2 ;

[0087] The projected area of ​​groove 131 is S1, where S1 = 240 mm. 2 ;

[0088] The projected area of ​​the second region is S6, where S6 = 36 mm². 2 ;

[0089] The distance between the edge of the groove 131 and the edge of the conductive element 20 is Y1, where Y1 = 2mm;

[0090] The distance Y2 between the edge of the conductive component 20 and the edge of the solder structure 30 is 1.5mm.

[0091] Based on the data in this embodiment, it can be calculated that:

[0092] The radius of groove 131 is R5.

[0093] The radius R6 of the welding structure 30, R6 = R5 - (Y1 + Y2) = 8.742 - (2 + 1.5) = 5.242 mm;

[0094] The area of the front projection of the welding structure 30 is S4, S4 = π(R6) 2 = 3.14 x 5.242 2 ≈ 86.282 mm 2 ;

[0095] The internal resistance R2 of the welding structure 30 satisfies the relationship: Wherein, p is the resistivity of the conductive part 20, and H is the thickness of the conductive part 20.

[0096] In summary, in the comparison between the comparative example 1 and the example 1, the two are consistent in the parameters of the front projection area of the welding structure 30, the distance between the edge of the groove 131 and the edge of the conductive part 20, and the distance between the edge of the conductive part 20 and the edge of the welding structure 30, in particular, the front projection area of the first square area 13 in the example 1 is equal to the front projection area of the groove 131 in the comparative example 1, that is, S5 = S1, however, it is worth noting that the front projection area of the groove 131 in the example 1 is significantly smaller than the front projection area of the groove 131 in the comparative example 1, that is, S3 < S1, the front projection area of the groove 131 in the example 1 is 91.154 mm 2 smaller than the front projection area of the groove 131 in the comparative example 1. Therefore, compared with the comparative example 1, the example 1 effectively reduces the front projection area of the groove 131 while ensuring sufficient welding area, thereby increasing the coating area of the active material layer 12 and improving the energy density of the battery cell. In addition, since the front projection area of the groove 131 in the example 1 is reduced, the front projection area of the insulating layer 40 can also be reduced synchronously, effectively saving the use of insulating material of the insulating layer 40 and saving costs.

[0097] In the comparison between Comparative Example 1 and Example 2, both are consistent in the parameters of the area of the orthographic projection of the groove 131, the distance between the edge of the groove 131 and the edge of the conductive piece 20, the distance between the edge of the conductive piece 20 and the edge of the solder print structure 30, the resistivity of the conductive piece 20, and the thickness of the conductive piece 20. In particular, the area of the orthographic projection of the first square area 13 in Example 2 is equal to the area of the orthographic projection of the groove 131 in Comparative Example 1, i.e. S5 = S1, and the area of the orthographic projection of the second area 211 in Example 2 is equal to the area of the orthographic projection of the solder print structure 30 in Comparative Example 1, i.e. S6 = S2. However, it is worth noting that the internal resistance of the solder print structure 30 in Example 2 is significantly smaller than that of the solder print structure 30 in Comparative Example 1, i.e. R2 < R1. Although no specific internal resistance values are given in Comparative Example 1 and Example 2, the internal resistance in Comparative Example 1 and Example 2 depends on the resistivity of the conductive piece 20, the thickness of the conductive piece 20, and the area of the orthographic projection of the solder print structure 30. Under the same resistivity of the conductive piece 20 and the thickness of the conductive piece 20, the area of the orthographic projection of the solder print structure 30 in Example 2 is larger, so it can be inferred that the internal resistance of the solder print structure 30 in Example 2 is lower than that of the solder print structure 30 in Comparative Example 1. Therefore, compared with Comparative Example 1, the area of the orthographic projection of the solder print structure 30 in Example 2 is larger, which not only enhances the connection strength between the conductive piece 20 and the tab body 10, but also significantly reduces the heat generated at the tab position during the charging and discharging process, thereby improving the safety and stability of the battery.

[0098] It is apparent to those skilled in the art that the present application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. The foregoing exemplary embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the present application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A battery pole piece, characterized by: The pole piece body (10) has a first square area (13) on which a groove (131) is arranged, the bottom wall of the groove (131) has a first area (1311), the conductive part (20) has a first connecting part (21) and a second connecting part (22), the first connecting part (21) is welded on the first area (1311), the first connecting part (21) has a second area (211) on which a welding mark structure (30) is formed, and the second connecting part (22) extends from one end of the first connecting part (21) to outside the groove (131); Wherein, along the thickness direction (a) of the pole piece body (10), when the projected area of the first connecting part (21) on the pole piece body (10) is smaller than the projected area of the first area (1311) on the pole piece body (10), the projected area of the groove (131) on the pole piece body (10) is smaller than the projected area of the first square area (13) on the pole piece body (10); when the projected area of the groove (131) on the pole piece body (10) is equal to the projected area of the first square area (13) on the pole piece body (10), the projected area of the welding mark structure (30) on the pole piece body (10) is greater than the projected area of the second area (211) on the pole piece body (10).

2. The battery pole piece of claim 1, wherein: The projected shape of the first connecting part (21) is consistent with the projected shape of the welding mark structure (30); And / or, the projected shape of the first connecting part (21) is consistent with the projected shape of the groove (131).

3. The battery pole piece of claim 1, wherein: The pole piece body (10) also has a second square area (14), the first square area (13) is located in the second square area (14), the second square area (14) is provided with an insulating layer (40) covering the groove (131), and the projected area of the insulating layer (40) on the pole piece body (10) is smaller than or equal to the projected area of the second square area (14) on the pole piece body (10) along the thickness direction (a) of the pole piece body (10).

4. The battery pole piece of claim 3, wherein: The projected shape of the insulating layer (40) is consistent with the projected shape of the groove (131); And / or, the projected shape of the insulating layer (40) is consistent with the projected shape of the first connecting part (21); And / or, the projected shape of the insulating layer (40) is consistent with the projected shape of the welding mark structure (30).

5. The battery pole piece of claim 3, wherein: The projected shape of the groove (131) is square, circular, elliptical, trapezoidal, hexagonal, octagonal or special-shaped; And / or, the projected shape of the first connecting part (21) is circular, elliptical, trapezoidal, hexagonal, octagonal or special-shaped; And / or, the positive projection shape of the welding mark structure (30) is circular, oval, trapezoidal, hexagonal, octagonal or irregular; And / or, the positive projection shape of the insulation layer (40) is square, circular, oval, trapezoidal, hexagonal, octagonal or irregular.

6. The battery electrode of any one of claims 1 to 5, wherein: The welding mark structure (30) is provided with one or more.

7. The battery electrode of any one of claims 1 to 5, wherein: The pole piece body (10) comprises a current collector (11) and an active material layer (12), the active material layer (12) is arranged on at least one surface of the current collector (11), along the length direction (b) of the current collector (11), the first square area (13) and the groove (131) are both arranged in the middle part of the active material layer (12), and the bottom wall of the groove (131) is the current collector (11).

8. An electric cell characterized by: The battery pole piece comprises a first pole piece, a second pole piece and a diaphragm arranged between the first pole piece and the second pole piece, the first pole piece, the diaphragm and the second pole piece are stacked and wound to form an electric core, and the first pole piece and / or the second pole piece is the battery pole piece according to any one of claims 1-7.

9. A battery, characterized by: The electric core comprises the electric core according to claim 8.

10. An electrical device, characterized by: The battery comprises the battery according to claim 9.

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