Electrode piece, electrode assembly, battery and electric equipment

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a pole piece, an electrode assembly, a battery and electric equipment, the pole piece comprises a pole piece body and a pole lug, the pole lug is arranged in the middle of the pole piece body, a weak part is arranged on the pole lug, and the weak part is located in an overlapping area of the pole lug and the pole piece body; the resistance of the tab to the pole piece is effectively reduced when the pole piece is wound, so that the current collector is prevented from being damaged or torn due to the fact that the corner of the tab pierces the current collector in the winding process.

Description

Technical Field

[0001] The utility model belongs to the technical field of batteries, and specifically relates to pole pieces, electrode components, batteries and electrical equipment. Background Art

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

[0003] In a battery, the position of the tab has an important impact on the overall performance of the battery. By placing the tab in the middle of the pole piece, the battery resistance can be reduced and the energy transmission efficiency of the battery can be improved. After the pole piece is wound, the curvature from the outermost circle to the center hole of the battery cell gradually increases. Since the tab is located in the inner circle of the battery winding, the curvature of the circle where the tab is located is larger.

[0004] However, due to the difference in thickness and material hardness between the tab and the current collector of the pole piece, the tab produces a certain resistance to bending deformation during the winding process of the battery cell, which will puncture the current collector at the welding position and cause tearing of the current collector. Utility Model Content

[0005] The purpose of the utility model is to provide a pole piece, an electrode assembly, a battery and an electrical device to address the deficiencies of the prior art, so as to solve the technical problem in the prior art that the pole ear generates a certain resistance to bending deformation during the winding process of the battery cell, which may puncture the collector at the welding position and cause the collector to tear.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] In a first aspect, the utility model provides a pole piece, comprising a pole piece body and a pole ear, wherein the pole ear is arranged in the middle of the pole piece body, and a weak portion is arranged on the pole ear, and the weak portion is located in the overlapping area between the pole ear and the pole piece body.

[0008] Preferably, there are multiple weak portions, and the multiple weak portions are arranged at intervals along the width direction of the pole piece body. Along the length direction of the pole piece body, each weak portion includes a first part and a second part, and adjacent first parts and second parts are arranged continuously or at intervals.

[0009] Preferably, along the length direction of the pole piece body, adjacent first parts and second parts are symmetrically arranged about the center line of the pole lug.

[0010] Preferably, one end of the first portion close to the center line of the pole lug and one end of the second portion close to the center line of the pole lug are inclined downward.

[0011] Preferably, the distance between the weak portion and the edge of the overlapping area is 0.1-2 mm.

[0012] Preferably, the weak portion is a through hole or a recessed structure.

[0013] Preferably, the pole lug comprises a plurality of conductive members, and along the thickness direction of the pole piece body, the plurality of conductive members are stacked and arranged in the middle of the pole piece body, and the weak portion is arranged on at least one of the conductive members.

[0014] In the second aspect, the utility model provides an electrode assembly, including a first pole piece, a second pole piece and a diaphragm, wherein the first pole piece, the diaphragm and the second pole piece are stacked and wound in sequence to form the electrode assembly, the polarity of the first pole piece and the second pole piece are opposite, and the first pole piece and / or the second pole piece are the pole pieces in the above-mentioned embodiments.

[0015] In a third aspect, the utility model provides a battery, comprising the electrode assembly in the above embodiment.

[0016] In a fourth aspect, the utility model provides an electrical device, comprising the battery in the above embodiment.

[0017] Compared with the prior art, the beneficial effects achieved by the utility model are:

[0018] The pole piece of the utility model is used in conjunction with the pole piece body and the pole ear. The pole ear is arranged in the middle of the pole piece body, which effectively reduces the internal resistance of the battery. A weak portion is arranged on the pole ear, and the weak portion is located in the overlapping area of ​​the pole ear and the pole piece body. This effectively reduces the resistance of the pole ear to the pole piece when the pole piece is wound, thereby preventing the corner of the pole ear from piercing the current collector during the winding process, causing damage or tearing of the current collector.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1It is a structural schematic diagram of the pole piece of the utility model.

[0022] Figure 2 It is a cross-sectional schematic diagram of the pole piece of the utility model.

[0023] Figure 3 It is a schematic diagram of the structure of the pole ear of the utility model.

[0024] Figure 4 It is a schematic diagram of the structure of the pole piece in the prior art.

[0025] The reference numerals are described as follows:

[0026] 100, pole piece;

[0027] 10. Pole body; 11. Current collector; 111. Empty foil area; 112. Coating area; 12. Active material layer;

[0028] 20. Tab; 21. Overlapping area; 22. Weak portion; 221. First portion; 222. Second portion; 23. Conductive member;

[0029] 30. Insulation parts;

[0030] b. The center line of the pole ear; c. The distance between the weak part and the edge of the overlapping area; d. The length direction of the pole piece body; e. The width direction of the pole piece body; f. The thickness direction of the pole piece body. DETAILED DESCRIPTION

[0031] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0032] Furthermore, the terms “first”, “second”, etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0033] In the utility model, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the utility model can be understood according to the specific circumstances.

[0034] The following will be combined with the attached Figures 1 to 4 The technical solutions in the embodiments of the utility model are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] The electrical equipment of the embodiment of the utility model includes a battery. The electrical equipment may be a car, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The car may be a fuel car, a gas car, or a new energy car, and the new energy car may be a pure electric car, a hybrid car, or an extended-range car, and the like; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiment of the present application does not impose any special restrictions on the above-mentioned electrical equipment.

[0036] The battery of the embodiment of the utility model comprises a shell, a top cover and an electrode assembly. The top cover is arranged on the opening of the shell and forms an accommodation space with the shell. The electrode assembly is arranged in the accommodation space.

[0037] The electrode assembly of the embodiment of the utility model comprises a first electrode sheet, a second electrode sheet and a diaphragm, wherein the first electrode sheet, the diaphragm and the second electrode sheet are stacked and wound in sequence to form the electrode assembly, and the polarity of the first electrode sheet and the second electrode sheet are opposite. One of the first electrode sheet and the second electrode sheet is a positive electrode sheet, and one of the first electrode sheet and the second electrode sheet is a negative electrode sheet.

[0038] Hereinafter, the first pole piece and / or the second pole piece are collectively referred to as pole piece 100 .

[0039] See also Figures 1 to 3The pole piece 100 of the embodiment of the utility model includes a pole piece body 10 and a pole ear 20, wherein the pole ear 20 is arranged in the middle of the pole piece body 10, and a weak portion 22 is arranged on the pole ear 20, and the weak portion 22 is located in the overlapping area 21 between the pole ear 20 and the pole piece body 10.

[0040] Compared with the prior art, the pole piece 100 of the embodiment of the utility model, through the coordinated use of the pole piece body 10 and the pole ear 20, the pole ear 20 is arranged in the middle of the pole piece body 10, which effectively reduces the internal resistance of the battery, and by providing a weak portion 22 on the pole ear 20, the weak portion 22 is located in the overlapping area 21 between the pole ear 20 and the pole piece body 10, which effectively reduces the resistance of the pole ear 20 to bending deformation when winding the pole piece 100, thereby avoiding the corner of the pole ear 20 piercing the current collector 11 during the winding process, causing damage or tearing of the current collector 11.

[0041] Also, see Figure 4 The inventors found that when the pole tab 20 is set on the pole piece body 10, due to the difference in the uniformity of the equipment and the pole piece body 10, it is inevitable that after welding, the center line b of the pole tab 20 and the length direction d of the pole piece body 10 are not perpendicular to each other, so that the pole tab 20 is skewed, and after winding the pole piece 100, it is easy to cause the corner of the pole tab 20 to pierce the current collector 11, causing the current collector 11 to be damaged or torn. Therefore, by providing a weak portion 22 on the pole tab 20, the weak portion 22 is located in the overlapping area 21 between the pole tab 20 and the pole piece body 10, and the resistance of the pole tab 20 to the bending deformation when the pole piece 100 is wound is effectively reduced, thereby avoiding the corner of the pole tab 20 piercing the current collector 11 during the winding process, causing the current collector 11 to be damaged or torn.

[0042] See also Figure 1 In some embodiments, the weak portion 22 is provided with a plurality of weak portions 22, and the plurality of weak portions 22 are arranged at intervals along the width direction e of the pole piece body 10. By providing a plurality of weak portions 22, and the plurality of weak portions 22 are arranged at intervals along the width direction e of the pole piece body 10, the plurality of weak portions 22 are effectively dispersed to avoid stress concentration, thereby making the pole ear 20 easier to bend and wind, and avoiding the situation where the pole ear 20 pierces the current collector 11 during the winding process.

[0043] Furthermore, multiple weak portions 22 are arranged at equal intervals along the width direction e of the pole piece body 10. By setting the intervals between the multiple weak portions 22, the multiple weak portions 22 are arranged at equal intervals, which effectively makes the multiple weak portions 22 evenly dispersed, so that the pole tab 20 is easier to bend and wind, and avoids the situation where the pole tab 20 pierces the current collector 11 during the winding process.

[0044] See also Figure 1In some embodiments, along the length direction d of the pole piece body 10, each of the weak parts 22 includes a first part 221 and a second part 222, and the adjacent first parts 221 and second parts 222 are arranged continuously or at intervals. By using the first part 221 and the second part 222 in coordination, the first part 221 and the second part 222 are arranged along the length direction of the pole piece 100, which effectively makes the pole tab 20 smoother during the winding process, and improves the bending and winding effect of the pole tab 20.

[0045] In addition, when the adjacent first portion 221 and the second portion 222 are continuously arranged, the continuously arranged first portion 221 and the second portion 222 enable the weak portion 22 to form a continuous guide path, effectively making the pole tab 20 smoother during the winding process. When the adjacent first portion 221 and the second portion 222 are arranged at intervals, not only is the resistance of the pole tab 20 to bending deformation effectively reduced when the pole sheet 100 is wound, but also, when the pole tab 20 has the weak portion 22, the pole tab 20 still has a larger flow area.

[0046] Further, along the length direction d of the pole piece body 10, the adjacent first portion 221 and the second portion 222 are symmetrically arranged about the center line b of the pole tab 20. During the winding process of the pole piece 100, it is generally wound along the length direction d of the pole piece body 10, and a winding center line is formed in the width direction e of the pole piece body 10. Since the center line b of the pole tab 20 is parallel to the width direction e of the pole piece body 10, the center line b of the pole tab 20 is parallel to the winding center line, which effectively ensures that the pole tab 20 is well aligned with the pole piece body 10 during the winding process to avoid dislocation or distortion.

[0047] In addition, the adjacent first part 221 and the second part 222 are symmetrical about the center line b of the pole lug 20, which effectively ensures that both sides of the center line of the pole lug 20 can be evenly stressed, better disperses the force, reduces stress concentration, and effectively makes the pole lug 20 smoother during the winding process.

[0048] Furthermore, one end of the first portion 221 close to the center line b of the pole tab 20 and one end of the second portion 222 close to the center line b of the pole tab 20 are tilted downward. During the winding process of the pole piece 100, in the overlapping area 21 between the pole tab 20 and the pole piece body 10, the corner of the pole tab 20 is easy to pierce the current collector 11 of the pole piece body 10, causing the current collector 11 to tear. Therefore, the end of the first portion 221 close to the center line of the pole tab 20 and the end of the second portion 222 close to the center line of the pole tab 20 are both tilted downward, effectively ensuring that the weakest area is formed at the corner of the pole tab 20, effectively avoiding the stress concentration at the corner of the pole tab 20, so that the corner of the pole tab 20 is easier to wind or bend, and avoiding the corner of the pole tab 20 piercing the current collector 11 and causing the current collector 11 to tear.

[0049] See also Figure 1 In some embodiments, the distance c between the weak portion 22 and the edge of the overlapping area 21 is 0.1-2 mm. By setting the distance c between the weak portion 22 and the edge of the overlapping area 21, a certain protective space is effectively provided for the weak portion 22 to avoid the weak portion 22 from contacting the edge of the overlapping area 21, which causes the pole tab 20 to tear or break during the winding process of the pole piece 100 due to the relatively fragile weak portion 22.

[0050] Further, the distance c between the weak portion 22 and the edge of the overlapping area 21 is 0.1-0.48 mm, 0.48-0.86 mm, 0.86-1.24 mm, 1.24-1.62 or 1.62-2 mm. Specifically, the distance c between the weak portion 22 and the edge of the overlapping area 21 is 0.1 mm, 0.15 mm, 0.24 mm, 0.4 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.64 mm, 0.75 mm, 0.84 mm, 1 mm, 1.3 mm, 1.5 mm, 1.8 mm, 1.9 mm or 2 mm, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0051] In some embodiments, the weak portion 22 is a through hole or a recessed structure. By making the weak portion 22 a through hole or a recessed structure, during the winding process of the pole piece 100, stress concentration can be reduced, and the resistance of the pole tab 20 to bending deformation can be reduced, thereby preventing the pole tab 20 from piercing the current collector 11 during the winding process.

[0052] In addition, since the through hole passes through the pole ear 20, the groove depth of the recessed structure is smaller than the thickness of the pole ear 20. In order to ensure the flow area of ​​the pole ear 20, in the thickness direction f of the pole piece body 10, the orthographic projection area of ​​the through hole on the pole ear 20 is smaller than 50% of the orthographic projection area of ​​the recessed structure on the pole ear 20.

[0053] See also Figure 1In some embodiments, the ratio of the thickness of the weak portion 22 to the thickness of the tab 20 is a, wherein 5%≤a≤100%. When the weak portion 22 is a concave structure, 5%≤a<100%; when the weak portion 22 is a through hole, a=100%.

[0054] In some embodiments, the bottom width of the weak portion 22 is smaller than the top width of the weak portion 22. Specifically, the cross-sectional shape of the weak portion 22 is a trapezoid, an inverted triangle, a semicircle, or a semi-ellipse.

[0055] See also Figures 1 to 3 In some embodiments, the pole tab 20 includes a plurality of conductive members 23, and along the thickness direction f of the pole piece body 10, the plurality of conductive members 23 are stacked in the middle of the pole piece body 10, and the weak portion 22 is arranged on at least one of the conductive members 23. Through the stacking arrangement of the plurality of conductive members 23, the flow area of ​​the pole tab 20 is effectively ensured, the resistance is reduced, the overall performance of the battery is improved, and the stable transmission of the current is ensured.

[0056] Further, the number of the conductive members 23 is greater than or equal to 3. Preferably, the number of the conductive members 23 is 5. This not only ensures the flow area of ​​the tab 20, but also prevents the tab 20 from being too thick, thereby affecting the energy density of the battery.

[0057] See also Figures 1-2 In some embodiments, the pole piece body 10 includes a current collector 11 and an active material layer 12 , the current collector 11 is provided with a coating area 112 and a middle hollow foil area 111 , the pole ear 20 is provided on the middle hollow foil area 111 , and the active material layer 12 is provided on the coating area 112 .

[0058] See also Figures 1-2 In some embodiments, the pole piece 100 further includes an insulating member 30, which is disposed on the active material layer 12 and covers the middle hollow foil area 111. By providing the insulating member 30, the burrs and puncture of the diaphragm after welding of the pole tab 20 can be effectively avoided, thereby preventing the electrode assembly from short-circuiting.

[0059] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

Claims

1. A pole piece, characterized in that: The invention comprises a pole piece body (10) and a pole ear (20), wherein the pole ear (20) is arranged in the middle of the pole piece body (10), and a weak portion (22) is arranged on the pole ear (20), and the weak portion (22) is located in an overlapping area (21) between the pole ear (20) and the pole piece body (10).

2. The pole piece according to claim 1, characterized in that: A plurality of the weak portions (22) are provided, and the plurality of the weak portions (22) are arranged at intervals along the width direction (e) of the pole piece body (10). Along the length direction (d) of the pole piece body (10), each of the weak portions (22) comprises a first portion (221) and a second portion (222), and adjacent first portions (221) and second portions (222) are arranged continuously or at intervals.

3. The pole piece according to claim 2, characterized in that: Along the length direction (d) of the pole piece body (10), the adjacent first part (221) and the second part (222) are symmetrically arranged about the center line (b) of the pole lug (20).

4. The pole piece according to claim 2, characterized in that: One end of the first portion (221) close to the center line (b) of the pole lug (20) and one end of the second portion (222) close to the center line (b) of the pole lug (20) are both inclined downward.

5. The pole piece according to claim 1, characterized in that: The distance (c) between the weak portion (22) and the edge of the overlapping area (21) is 0.1 to 2 mm.

6. The pole piece according to claim 1, characterized in that: The weak portion (22) is a through hole or a recessed structure.

7. The pole piece according to claim 1, characterized in that: The pole lug (20) comprises a plurality of conductive members (23), and along the thickness direction (f) of the pole piece body (10), the plurality of conductive members (23) are stacked and arranged in the middle of the pole piece body (10), and the weak portion (22) is arranged on at least one of the conductive members (23).

8. An electrode assembly, characterized in that: The electrode assembly comprises a first pole piece, a second pole piece and a diaphragm, wherein the first pole piece, the diaphragm and the second pole piece are stacked and wound in sequence to form the electrode assembly, the first pole piece and the second pole piece have opposite polarities, and the first pole piece and / or the second pole piece are the pole pieces described in any one of claims 1 to 7.

9. A battery, characterized in that: Comprising the electrode assembly according to claim 8.

10. An electrical equipment, characterized in that: A battery comprising the battery of claim 9.

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