Battery negative plate and battery pole group

Abstract

The utility model discloses a battery negative plate and a battery pole group. The negative plate comprises a negative plate main body, the negative plate main body comprises a negative current collector; the middle part of the front side and the middle part of the rear side of the negative current collector are respectively coated with a negative active material coating; a core negative lug is welded at the left end of the front side of the negative current collector; the upper part of the core negative lug protrudes out of the top of the negative current collector; a core part negative electrode lug protection adhesive tape is adhered to the core part negative electrode lug in a covering manner; the upper and lower ends of the core negative lug protection adhesive tape respectively protrude out of the top and bottom of the negative current collector; the right end of the core negative lug protection adhesive tape covers the left end of the negative active material coating on the front side of the negative current collector; a tail protection adhesive tape is adhered to the right end of the front side of the negative current collector; and the left end of the tail protection adhesive tape covers the negative active material coating at the right end of the front side of the negative current collector. According to the utility model, the fracture problem of the high-silicon system cathode current collector can be effectively improved, the fracture risk is reduced, and the structural stability of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery negative electrode sheet and a battery electrode group. Background Art

[0002] At present, lithium-ion batteries have the advantages of high specific energy, many cycles and long storage time. They are not only widely used in portable electronic devices (such as mobile phones, digital cameras and laptops), but also widely used in large and medium-sized electric equipment such as electric vehicles, electric bicycles and electric tools. Therefore, the performance requirements for lithium-ion batteries are getting higher and higher.

[0003] The negative electrode of high energy density lithium-ion battery usually contains a high content of silicon. Since silicon inevitably expands in volume during the charge and discharge process, the negative electrode current collector breaks. In order to achieve both high energy density and good rate performance, the negative electrode is usually designed as a core and tail bipolar ear structure, or a single-pole ear structure with the ear located in the middle, core or tail, which is achieved by copper foil wall bonding.

[0004] In the negative electrode sheets of high energy density and high silicon system, for the negative electrode sheets with bipolar lug structure, the copper foil at the tail lug breaks along the root and side of the lug due to the expansion of the lug.

[0005] For the pole piece structure with a single pole ear at the negative electrode core and no tail pole ear, in order to reduce the internal resistance and improve the rate performance, most of them choose to end with copper foil, wrap the pole group with the end tape, and leave part of the copper foil attached to the wall. However, this pole piece structure with a single pole ear at the negative electrode core and no tail pole ear often has no tape attached at the landing point of the cut end of the positive electrode piece, which leads to the risk of fracture of the negative electrode current collector at the landing point of the positive electrode. In the high silicon system, the fracture of the negative electrode current collector is more obvious.

[0006] Therefore, for high-silicon cylindrical lithium-ion batteries, it is particularly important to design an electrode and electrode group structure that can improve the problem of negative electrode current collector fracture. Utility Model Content

[0007] The purpose of the utility model is to provide a battery negative electrode sheet and a battery electrode group in view of the technical defects in the prior art.

[0008] To this end, the utility model provides a battery negative electrode sheet, which includes a negative electrode sheet body;

[0009] A negative electrode sheet body, including a negative electrode current collector;

[0010] A layer of negative electrode active material coating is coated on the middle of the front side and the middle of the rear side of the negative electrode current collector respectively;

[0011] Neither the front left end nor the rear left end of the negative electrode current collector is coated with a negative electrode active material coating, and a vertically distributed core negative electrode ear is welded to the front left end of the negative electrode current collector;

[0012] The upper part of the core negative electrode ear protrudes from the top of the negative electrode current collector;

[0013] A core negative electrode ear protective tape is pasted on the core negative electrode ear in a covering manner;

[0014] The upper and lower ends of the core negative electrode ear protection tape protrude from the top and bottom of the negative electrode current collector respectively;

[0015] The right end of the core negative electrode ear protection tape covers the left end of the negative electrode active material coating on the front side of the negative electrode current collector;

[0016] Neither the front right end nor the rear right end of the negative electrode current collector is coated with a negative electrode active material coating, and a tail protection tape is attached to the front right end of the negative electrode current collector;

[0017] The left end of the tail protection tape covers the negative electrode active material coating on the right end of the front side of the negative electrode current collector.

[0018] It can be seen from the technical solution provided by the above utility model that, compared with the prior art, the utility model provides a battery negative electrode sheet and a battery electrode group, which have a scientific structural design, can effectively improve the fracture problem of the high-silicon system negative electrode collector, reduce the risk of fracture, and improve the structural stability of the battery, which has great practical significance.

[0019] By applying the utility model, the problem of copper foil breakage at the tail ear of the negative electrode sheet and the corresponding negative electrode current collector (i.e. negative electrode copper foil) breakage at the cut end of the positive electrode sheet can be improved, thereby improving the structural stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a negative electrode sheet of a battery provided by the utility model;

[0021] Figure 2 A schematic diagram of the structure of a positive electrode sheet of a battery electrode group provided by the utility model, wherein the positive electrode sheet cooperates with Figure 1 The battery negative electrode sheet shown is used together to prepare a cylindrical battery electrode group;

[0022] Figure 3 A schematic diagram of the positional relationship of a negative electrode sheet, a positive electrode sheet and a termination tape in a battery electrode group provided by the utility model;

[0023] In the figure: 1 is the negative electrode sheet body; 2 is the core negative electrode ear; 3 is the core negative electrode ear protection tape; 4 is the tail protection tape; 5 is the negative electrode current collector (specifically copper foil);

[0024] 6 is a negative electrode active material coating;

[0025] 20 is the main body of the positive electrode sheet; 21 is the positive electrode ear; 22 is the positive electrode current collector (specifically, aluminum foil); 23 is the positive electrode tail protective tape; 24 is the cut end of the positive electrode sheet;

[0026] 30 is the battery electrode group body; 40 is the end tape. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. 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.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element 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 invention.

[0029] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] See also Figures 1 to 3 The utility model provides a battery negative electrode sheet, which is applied to a cylindrical lithium-ion battery, and is a cylindrical lithium-ion battery negative electrode sheet, which includes a negative electrode sheet body 1;

[0032] The negative electrode sheet body 1 includes a negative electrode current collector (specifically copper foil) 5;

[0033] The middle of the front side and the middle of the back side of the negative electrode current collector (specifically copper foil) 5 are coated with a layer of negative electrode active material coating 6 respectively; that is, the front side and both ends of the back side of the negative electrode current collector are pure copper foil parts without coating.

[0034] It should be noted that the negative electrode current collector (specifically copper foil) 5 is not coated with the negative electrode active material coating 6 at the front side and the left and right ends of the rear side;

[0035] Neither the front left end nor the rear left end of the negative electrode current collector 5 is coated with the negative electrode active material coating 6, and a vertically distributed core negative electrode ear 2 is welded to the front left end of the negative electrode current collector 5;

[0036] It should be noted that the rear left end of the negative electrode current collector 5 is not coated with the negative electrode active material coating 6, and the front left end and the rear left end of the negative electrode current collector 5 where the negative electrode active material coating 6 is not coated correspond to each other and have the same size.

[0037] The upper part of the core negative electrode ear 2 protrudes from the top of the negative electrode current collector 5;

[0038] A core negative electrode ear protection tape 3 is pasted on the core negative electrode ear 2 in a covering manner;

[0039] The upper and lower ends of the core negative electrode ear protection tape 3 protrude from the top and bottom of the negative electrode current collector 5 respectively;

[0040] The right end (i.e., the inner end) of the core negative electrode ear protection tape 3 covers the left end of the negative electrode active material coating 6 on the front side of the negative electrode current collector 5;

[0041] Neither the front right end nor the rear right end of the negative electrode current collector 5 is coated with the negative electrode active material coating 6, and the front right end of the negative electrode current collector 5 is pasted with a tail protection tape 4;

[0042] It should be noted that the rear right end of the negative electrode current collector 5 is not coated with the negative electrode active material coating 6, and the positions of the areas where the front right end and the rear right end of the negative electrode current collector 5 are not coated with the negative electrode active material coating 6 correspond front to back, and the area of ​​the uncoated area at the front right end of the negative electrode current collector 5 is smaller than the area of ​​the uncoated area at the rear right end.

[0043] The left end (ie the inner end) of the tail protection tape 4 covers the negative electrode active material coating on the front right end of the negative electrode current collector 5 .

[0044] It should be noted that the front right end of the negative electrode current collector 5 has no tail negative electrode ear.

[0045] In the present invention, in a specific implementation, the shape of the negative electrode sheet body 1 (ie, the shape when it is in an unfolded state before being wound into the battery electrode group) is a rectangle.

[0046] In the present utility model, the specific implementation is as follows: Figure 1 As shown, the left end (ie, the inner end) of the tail protection tape 4 covers the right end of the negative electrode active material coating 6 on the front side of the negative electrode current collector 5 by a length (lateral covering length) of 4 to 8 mm.

[0047] It should be noted that the right end of the negative electrode current collector 5 contains a tail protection tape 4, which is distributed at the starting end of the tail protection tape 4 on the inner side of the winding, 4 to 8 mm away from the end of the negative electrode powder (that is, the coverage length at the right end of the negative electrode active material coating 6 is 4 to 8 mm).

[0048] In the present invention, in a specific implementation, the upper and lower ends of the core negative electrode ear protection tape 3 protrude from the top and bottom of the negative electrode current collector 5 by a distance of 1 to 2 mm, respectively.

[0049] In the present invention, in a specific implementation, the upper and lower ends of the tail protection tape 4 protrude from the top and bottom of the negative electrode current collector 5 by a distance of 1 to 2 mm, respectively.

[0050] Based on the battery negative electrode sheet provided by the utility model, the utility model further provides a battery electrode group, which is a cylindrical lithium-ion battery electrode group, and includes a battery electrode group body 30;

[0051] The battery electrode group body 30 includes the battery negative electrode sheet and the positive electrode sheet as described above;

[0052] A positive electrode sheet, comprising a positive electrode sheet body 20;

[0053] The positive electrode sheet body 20 includes a positive electrode current collector (specifically, aluminum foil) 22;

[0054] The left and right ends of the front and rear sides of the positive electrode current collector 22 have a left uncoated section 221 and a right uncoated section 222, respectively.

[0055] It should be noted that the rear side of the positive electrode current collector 22 has a similar structure to the front side, with no active material at both ends and at the middle pole ear, and active material at the remaining part.

[0056] It should be noted that the left uncoated sections 221 on the front and rear sides of the positive electrode current collector 22 are arranged in a front-to-back correspondence. The right uncoated sections 222 on the front and rear sides of the positive electrode current collector 22 are arranged in a front-to-back correspondence.

[0057] It should also be noted that the right-end uncoated sections 222 on the front and rear sides of the positive electrode current collector 22 are staggered in front and back, and the actual end position of the right-end uncoated section of the positive electrode current collector 22 is staggered, and the right-end uncoated sections 222 on the front and rear sides of the positive electrode current collector 22 do not completely overlap. The incomplete overlap is to reduce the thickness difference and prevent the foil from breaking. The area of ​​the right-end uncoated section on the front side of the positive electrode current collector 22 is smaller than the area of ​​the right-end uncoated section on the rear side.

[0058] On the front and rear sides of the positive electrode current collector 22, between the left uncoated section 221 and the right uncoated section 222, a vertically distributed middle uncoated section 220 is respectively provided;

[0059] It should be noted that the middle uncoated sections 220 on the front and rear sides of the positive electrode current collector 22 are arranged in a front-to-back correspondence.

[0060] It should be noted that the left-end uncoated section 221, the right-end uncoated section 222 and the middle uncoated section 220 are all portions that are not coated with the positive electrode active material coating 7;

[0061] The front and rear sides of the positive electrode current collector, except for the left uncoated section 221 , the right uncoated section 222 and the middle uncoated section 220 , are coated with a positive electrode active material coating 7 .

[0062] A vertically distributed positive electrode ear 21 is welded on the middle uncoated section 220 on the front side of the positive electrode current collector 22;

[0063] The upper portion of the positive electrode ear 21 protrudes from the top of the positive electrode current collector 22;

[0064] A positive electrode tail protection tape 23 is attached to the front right end of the positive electrode current collector 22;

[0065] It should be noted that there is no tail positive electrode lug at the front right end of the positive electrode collector 22 .

[0066] The upper and lower ends of the positive electrode tail protection tape 23 protrude from the top and bottom of the positive electrode current collector 22 respectively;

[0067] The left end (ie, the inner end) of the positive electrode tail protection tape 23 covers the right end of the positive electrode active material coating 7 on the front side of the positive electrode current collector 22 .

[0068] In the present invention, a diaphragm is provided between the negative electrode sheet and the positive electrode sheet of the battery; the diaphragm is used to separate the negative electrode sheet and the positive electrode sheet of the battery. This is an existing conventional design and will not be described in detail here.

[0069] In the present invention, in a specific implementation, the middle and lower parts of the positive electrode tab 21 are covered with a positive electrode tab protection tape 210;

[0070] The upper and lower ends of the positive electrode tab protection tape 210 protrude from the top and bottom of the positive electrode current collector 22 respectively.

[0071] In the present invention, in a specific implementation, a positive electrode head protection tape 2210 is pasted in a covering manner on the left end uncoated section 221;

[0072] The upper and lower ends of the positive electrode head protection tape 2210 protrude from the top and bottom of the positive electrode current collector 22 respectively.

[0073] In specific implementation, the right end (i.e., the inner end) of the positive electrode head protection tape 2210 covers the positive electrode active material coating 7 on the front side of the positive electrode current collector 22;

[0074] In the present invention, in a specific implementation, a finishing tape 40 (i.e., a termination tape) is attached to the end of the battery electrode group body 30;

[0075] The tape 40 is then bonded to the negative electrode sheet body 1 .

[0076] In a specific implementation, in the radial direction of the battery electrode group body 30 , the negative electrode sheet body 1 is located outside the positive electrode sheet body 20 .

[0077] In a specific implementation, the end tape 40 is bonded to the negative electrode active material coating 6 and the negative electrode current collector 5 (ie, copper foil) on the end end (ie, right end) of the negative electrode sheet body 1 .

[0078] In specific implementation, the left end (i.e., the inner end) of the end tape 40 (i.e., the end tape) is 1.5 meters away from the negative electrode powder end (i.e., the negative electrode active material coating 6 on the negative electrode sheet body 1) of the negative electrode active material coating 6. Figure 3 The distance from the right end (as shown) is 3 to 7 mm.

[0079] In a specific implementation, the length of the end tape 40 (ie, the terminating tape) (ie, the length after being laid out horizontally) does not exceed 1 / 2 of the circumference of the battery electrode group (specifically, the finished battery electrode group after winding).

[0080] That is to say, the starting position of the end tape 40 (i.e., the end tape) is 3 to 7 mm away from the end of the negative electrode powder of the negative electrode active material coating 6 on the negative electrode sheet body 1; and the length of the end tape wrapped around the electrode group does not exceed 1 / 2 of the circumference of the electrode group.

[0081] It should be noted that, for the present invention, the termination tape 40 is pasted after winding is completed to prevent the electrode group from loosening, and is pasted on the rear side of the negative electrode copper foil tail (because the negative electrode copper foil ends at the end of the electrode group winding). It is different from the positive electrode tail protection tape.

[0082] In the present utility model, in a specific implementation, in a battery electrode group, a positive electrode sheet main body 20 has a positive electrode sheet cut end 24;

[0083] The positive electrode sheet cut end 24 is located between the tape edge of the tail protection tape 4 on the negative electrode sheet and the edge of the negative electrode powder of the adjacent negative electrode active material coating.

[0084] It should be noted that regarding the cut end of the positive electrode sheet, because the slurry coating operation on the positive electrode sheet in the early stage (coating the active material on the aluminum foil serving as the positive electrode current collector) is continuous and needs to be cut during the battery manufacturing process, the negative electrode copper foil is prone to breakage at the cut end of the positive electrode. This is caused by the sudden change in the thickness of the positive electrode and the expansion of the high-silicon system of the negative electrode. The placement of the cut end of the positive electrode sheet will affect the severity of the breakage of the negative electrode copper foil.

[0085] For the utility model, for the negative electrode sheet, due to the presence of the negative electrode protection tape (i.e., the tail protection tape 4), the breakage of the negative electrode copper foil can be alleviated, because the positive electrode cut end acts on the negative electrode protection tape (i.e., the tail protection tape 4), which can alleviate the breakage problem caused by the thickness difference and the expansion of the negative electrode sheet. If it does not fall on the tape, there will be one less layer of buffer. In addition, falling on the negative electrode protection tape (i.e., the tail protection tape 4) can also reduce the risk of short circuit when the diaphragm of the positive electrode cut end is damaged (the diaphragm will not be damaged under normal circumstances). In addition, for the utility model, the positive electrode sheet cut end falls on the tape cover powder (i.e., the negative electrode powder position of the negative electrode active material coating to which the tape is attached) instead of the copper foil, because the copper foil is thinner, if the positive electrode cut end falls on the copper foil, the copper foil will still be cut off due to the expansion of the negative electrode sheet.

[0086] In a specific implementation, the distance between the cut end 24 of the positive electrode sheet and the end of the negative electrode powder of the negative electrode active material coating 6 on the negative electrode sheet is 2 to 6 mm.

[0087] It should be noted that the cut end 24 of the positive electrode sheet in the electrode group should fall between the tape edge of the tail protective tape 4 on the negative electrode sheet and the edge of the negative electrode powder of the adjacent negative electrode active material coating and on the side where the tape covers the powder (i.e., the tail protective tape 4 covers the negative electrode powder), and the distance between the cut end 24 of the positive electrode sheet and the end end of the negative electrode powder of the negative electrode active material coating 6 on the negative electrode sheet is 2 to 6 mm.

[0088] In a specific implementation, the position of the cut end 24 of the positive electrode sheet cannot coincide with the position where the positive electrode tail protective tape 23 starts.

[0089] It should be noted that, for the present invention, the protective tape is pasted on the tail of the negative electrode sheet, and the cut end of the positive electrode sheet is required to fall on the tail protective tape 4 of the negative electrode sheet, and fall on the position where the tape covers the powder, rather than the position where the copper foil is not covered by the tape, and cannot overlap with the starting position of the termination tape (i.e., the termination tape 40). It should be noted that if the position of the cut end 24 of the positive electrode sheet overlaps with the position of the termination tape (i.e., the termination tape 40), there will be a thickness difference on both sides of the negative electrode sheet at the corresponding position, and the negative electrode sheet will expand, resulting in a greatly increased risk of fracture at the overlap.

[0090] For the present invention, the reason why the cut end of the positive electrode sheet is required to fall on the tail protective tape of the negative electrode sheet is because: the existence of the negative electrode protective tape (i.e., the tail protective tape 4) can alleviate the breakage of the negative electrode copper foil, because the cut end of the positive electrode acts on the negative electrode tape (i.e., the tail protective tape 4), which can alleviate the breakage problem caused by the thickness difference and the expansion of the negative electrode sheet. If it does not fall on the tape, there will be one less layer of buffer.

[0091] For the utility model, the reason why the cut end of the positive electrode sheet is required to fall on the position where the tape covers the powder is because: it is required to fall on the tape cover powder (that is, the position of the negative electrode powder of the negative electrode active material coating to which the tape is attached) rather than on the copper foil. Because the copper foil is thinner, if the cut end of the positive electrode falls on the copper foil, the copper foil will still be cut off due to the expansion of the negative electrode sheet.

[0092] In addition, if the position of the cut end 24 of the positive electrode sheet coincides with the position of the termination tape (ie, the end tape 40), there will be a thickness difference on both sides of the negative electrode sheet at the corresponding position, and the negative electrode sheet will expand, which will greatly increase the risk of fracture at the overlapped position.

[0093] Compared with the prior art, the utility model provides a battery negative electrode sheet and a battery electrode group, which have a scientific structural design, can effectively improve the fracture problem of the negative electrode current collector of the high-silicon system, reduce the risk of fracture, and improve the structural stability of the battery, and has great practical significance.

[0094] By applying the utility model, the problem of copper foil breakage at the tail ear of the negative electrode sheet and the corresponding negative electrode current collector (i.e. negative electrode copper foil) breakage at the cut end of the positive electrode sheet can be improved, thereby improving the structural stability of the battery.

[0095] It should be noted that, for the utility model, the positive electrode cut end acts on the negative electrode tape (i.e., the tail protective tape 4 of the negative electrode sheet) (specifically, the position where the tape covers the powder), which can alleviate the problem of copper foil breakage caused by the thickness difference caused by the sudden end of the positive electrode sheet and the expansion of the negative electrode sheet. The position of the positive electrode sheet cut end 24 does not coincide with the position of the termination tape (i.e., the ending tape 40), reducing the risk of copper foil breakage caused by the thickness difference on both sides of the negative electrode sheet at the corresponding position when the negative electrode sheet expands.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A battery negative electrode sheet, characterized in that: It includes a negative electrode sheet body (1); A negative electrode sheet body (1) comprising a negative electrode current collector (5); A layer of negative electrode active material coating (6) is coated on the middle of the front side and the middle of the rear side of the negative electrode current collector (5); The front left end and the rear left end of the negative electrode current collector (5) are not coated with the negative electrode active material coating (6), and the front left end of the negative electrode current collector (5) is welded with a vertically distributed core negative electrode ear (2); The upper part of the core negative electrode ear (2) protrudes from the top of the negative electrode current collector (5); A core negative electrode ear protection tape (3) is adhered to the core negative electrode ear (2) in a covering manner; The upper and lower ends of the core negative electrode ear protection tape (3) protrude from the top and bottom of the negative electrode current collector (5) respectively; The right end of the core negative electrode ear protection tape (3) covers the left end of the negative electrode active material coating (6) on the front side of the negative electrode current collector (5); The front right end and the rear right end of the negative electrode current collector (5) are not coated with the negative electrode active material coating (6), and the front right end of the negative electrode current collector (5) is affixed with a tail protection tape (4); The left end of the tail protection tape (4) covers the negative electrode active material coating at the right end of the front side of the negative electrode current collector (5).

2. The battery negative electrode sheet according to claim 1, characterized in that: The shape of the negative electrode sheet body (1) when in an unfolded state is rectangular.

3. The battery negative electrode sheet according to claim 1, characterized in that: The left end of the tail protection tape (4) covers the right end of the negative electrode active material coating (6) on the front side of the negative electrode current collector (5) by a length of 4 to 8 mm.

4. The battery negative electrode sheet according to claim 1, characterized in that: The upper and lower ends of the core negative electrode ear protection tape (3) protrude from the top and bottom of the negative electrode current collector (5) by a distance of 1 to 2 mm.

5. The battery negative electrode sheet according to any one of claims 1 to 4, characterized in that: The upper and lower ends of the tail protection tape (4) protrude from the top and bottom of the negative electrode current collector (5) by a distance of 1 to 2 mm, respectively.

6. A battery electrode group, characterized in that: It includes a battery electrode group body (30); The battery electrode group body (30) comprises a battery negative electrode sheet as claimed in any one of claims 1 to 5, and a positive electrode sheet.

7. The battery electrode group according to claim 6, characterized in that: A positive electrode sheet, comprising a positive electrode sheet body (20); A positive electrode sheet body (20) comprising a positive electrode current collector (22); The left and right ends of the front and rear sides of the positive electrode current collector (22) respectively have a left-end uncoated section (221) and a right-end uncoated section (222); A vertically distributed middle uncoated section (220) is respectively provided on the front side and the rear side of the positive electrode current collector (22), between the left-end uncoated section (221) and the right-end uncoated section (222); The front and rear sides of the positive electrode current collector, except for the left uncoated section (221), the right uncoated section (222) and the middle uncoated section (220), are coated with a positive electrode active material coating (7); A vertically distributed positive electrode ear (21) is welded to the middle uncoated section (220) on the front side of the positive electrode current collector (22); The upper portion of the positive electrode ear (21) protrudes from the top of the positive electrode current collector (22); A positive electrode tail protection tape (23) is attached to the front right end of the positive electrode current collector (22); The upper and lower ends of the positive electrode tail protection tape (23) protrude from the top and bottom of the positive electrode current collector (22) respectively; The left end of the positive electrode tail protection tape (23) covers the right end of the positive electrode active material coating (7) on the front side of the positive electrode current collector (22).

8. The battery electrode group according to claim 7, characterized in that: The middle and lower parts of the positive electrode lug (21) are covered with a positive electrode lug protection tape (210); The upper and lower ends of the positive electrode tab protection tape (210) protrude from the top and bottom of the positive electrode current collector (22), respectively.

9. The battery electrode group according to claim 7, characterized in that: A positive electrode head protection tape (2210) is pasted in a covering manner on the left end uncoated section (221); The upper and lower ends of the positive electrode head protection tape (2210) protrude from the top and bottom of the positive electrode current collector (22) respectively; The right end of the positive electrode head protection tape (2210) covers the positive electrode active material coating (7) on the front side of the positive electrode current collector (22).

10. The battery electrode group according to claim 9, characterized in that: The end of the battery electrode assembly body (30) is attached with an end tape (40); End tape (40), bonded to the negative electrode sheet body (1); The left end of the tape (40) is 3 to 7 mm from the end of the negative electrode powder of the negative electrode active material coating (6) on the negative electrode sheet body (1); The length of the end tape (40) shall not exceed 1 / 2 of the circumference of the battery electrode group.

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