Diaphragm, battery and electric equipment

Abstract

The utility model relates to the technical field of batteries, in particular to a diaphragm, a battery and electric equipment, the diaphragm comprises a diaphragm body and a lug boss, the lug boss is connected with the diaphragm body, and the lug boss is used for being matched with a pole piece. According to the diaphragm, the battery and the electric equipment disclosed by the utility model, the convex part is arranged on the diaphragm body, so that the diaphragm body with the convex part can be matched with the pole piece comprising the etched concave part in a concave-convex manner; the long circulation capability of the battery is effectively improved, the service life of the battery is prolonged, the safety performance of the battery is improved, the capacity retention rate of the battery is improved, and the production and preparation efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a diaphragm, a battery and electrical equipment. Background Art

[0002] With the development of the new energy industry, the demand for batteries is growing, and people are paying more and more attention to battery performance. Among them, people increase the thickness of the electrode coating through thick electrode technology to improve the energy density of the battery. However, as the coating thickness increases, the lithium ion transmission distance is also increased, the reversible capacity is reduced, and the irreversible lithium deposition is worsened.

[0003] In order to alleviate the above problems, people use laser etching to form an etched concave structure to increase the wettability of the electrolyte and reduce the curvature of the electrode. However, laser etching of the electrode coating also brings new problems.

[0004] First, the edges of the area etched by laser will be burned, and the laser surface is prone to unevenness, which affects the long cycle life of the battery. Secondly, the cut surface area is prone to powder loss, causing short circuits and other problems. Finally, the etched channel structure formed by etching on the surface of the electrode is also prone to cause large gaps during the assembly of the positive and negative electrode sheets and diaphragms, causing low capacitance. Utility Model Content

[0005] To this end, the technical problem to be solved by the utility model is to overcome the uneven burnt edges, powder loss, and large assembly gaps of the laser-etched electrode coating, and to provide a diaphragm, a battery, and electrical equipment that can extend the battery cycle life, improve the battery safety performance, and enhance the battery capacity retention rate.

[0006] In a first aspect, the utility model provides a diaphragm, comprising a diaphragm body; a protrusion, wherein the protrusion is connected to the diaphragm body, and the protrusion is used to cooperate with a pole piece.

[0007] In one embodiment of the utility model, there are multiple protrusions, and the multiple protrusions are arranged in sequence and spaced apart along the length direction of the diaphragm body, or the multiple protrusions are arranged in sequence and spaced apart along the width direction of the diaphragm body, and the interval between adjacent protrusions is set to 100μm~600μm.

[0008] In an embodiment of the present invention, the protrusion is a coating of any one of CMC, PVDF, POA, PMMA, and aramid.

[0009] In the second aspect, the utility model also provides a battery, comprising a positive electrode sheet, a negative electrode sheet and any one of the above-mentioned diaphragms, wherein the diaphragm body is located between the positive electrode sheet and the negative electrode sheet; wherein the positive electrode sheet has a first recessed portion on the surface along the thickness direction of the diaphragm body, and the first recessed portion is used to cooperate with the protruding portion; the negative electrode sheet has a second recessed portion on the surface along the thickness direction of the diaphragm body, and the second recessed portion is used to cooperate with the protruding portion.

[0010] In one embodiment of the present invention, along the first direction, the size W of the first recess is 1 and the size W of the second recess 2 are all set to 0-100 μm; along the second direction, the size H of the first concave portion 1 and the dimension H of the second recess 2 All are set to 0 to 40 μm.

[0011] In one embodiment of the present invention, the cross-sectional shape of the protrusion is a rectangle, and along the first direction, the dimension y of the protrusion is equal to the dimension W of the first recess. 1 Meets 0.85W 1 ≤y≤1.00W 1 .

[0012] In one embodiment of the present invention, the cross-sectional shape of the protrusion is a rectangle, and along the second direction, the dimension x of the protrusion is equal to the dimension H of the first recess. 1 Meet 0.05H 1 ≤x≤0.30H 1 .

[0013] In one embodiment of the present invention, the cross-sectional shape of the protrusion is a rectangle, and along the first direction, the dimension y of the protrusion is equal to the dimension W of the second concave portion. 2 Meets 0.85W 2 ≤y≤1.00W 2 .

[0014] In one embodiment of the present invention, the cross-sectional shape of the protrusion is a rectangle, and along the second direction, the dimension x of the protrusion is equal to the dimension H of the second recess. 2 Meet 0.05H 2 ≤x≤0.30H 2 .

[0015] In a third aspect, the utility model further provides an electrical device, comprising any one of the batteries described above.

[0016] The above technical solution of the utility model has the following advantages compared with the prior art:

[0017] The diaphragm, battery and electrical equipment described in the utility model are provided with a protrusion on the diaphragm body so that the diaphragm body provided with the protrusion can be matched with the pole piece including the etched concave portion. Since the diaphragm body can be matched with the pole piece including the etched concave portion through the protrusion, firstly, the problem of unevenness of the laser etched surface of the pole piece can be alleviated, and the long cycle capacity and service life of the battery can be improved. Secondly, the problem of powder loss of the pole piece and the movement of powder inside the battery can be prevented, and the problem of short circuit can be prevented, thereby improving the safety performance of the battery. In addition, the contact area between the diaphragm body and the pole piece is increased, and the problem of a large gap between the etched concave portion of the pole piece and the diaphragm body is avoided, the low capacity phenomenon is avoided, and the capacity retention rate of the battery is improved. Finally, the diaphragm body can be compounded with the pole piece in advance through the protrusion, which effectively improves the production and preparation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the content of the utility model easier to understand, the utility model is further described in detail according to the specific embodiments of the utility model in combination with the accompanying drawings, wherein:

[0019] Figure 1 This is one of the structural schematic diagrams of the diaphragm in the preferred embodiment of the utility model;

[0020] Figure 2 This is the second structural schematic diagram of the diaphragm in the preferred embodiment of the utility model;

[0021] Figure 3 This is the third structural diagram of the diaphragm in the preferred embodiment of the utility model;

[0022] Figure 4 This is the fourth structural schematic diagram of the diaphragm in the preferred embodiment of the utility model;

[0023] Figure 5 This is the fifth structural diagram of the diaphragm in the preferred embodiment of the utility model;

[0024] Figure 6 This is the sixth structural diagram of the diaphragm in the preferred embodiment of the utility model;

[0025] Figure 7 This is one of the structural schematic diagrams of the positive electrode sheet in the preferred embodiment of the utility model;

[0026] Figure 8 This is the second structural schematic diagram of the positive electrode sheet in the preferred embodiment of the utility model;

[0027] Fig. 9 One of the structural schematic diagrams of the negative electrode sheet in the preferred embodiment of the utility model;

[0028] Fig.10 The second structural diagram of the negative electrode sheet in the preferred embodiment of the utility model;

[0029] Fig.11 This is one of the schematic diagrams of the pole piece stacking structure in the preferred embodiment of the utility model;

[0030] Fig.12 A schematic diagram of the size relationship between the pole piece and the diaphragm in a preferred embodiment of the utility model;

[0031] Fig.13 The second schematic diagram of the pole piece stacking structure in the preferred embodiment of the utility model;

[0032] Fig.14 The third schematic diagram of the stacked structure of the pole pieces in the preferred embodiment of the utility model;

[0033] Fig.15 Schematic diagram of the pole piece stacking structure in the preferred embodiment of the utility model;

[0034] Fig.16 Schematic diagram of the pole piece stacking structure in the preferred embodiment of the utility model in the fifth embodiment;

[0035] Fig.17 The sixth schematic diagram of the pole piece stacking structure in the preferred embodiment of the utility model.

[0036] Explanation of the reference numerals in the specification: D1, first direction; D2, second direction; 10, diaphragm body; 11, raised portion; 21, positive electrode sheet; 211, first recessed portion; 22, negative electrode sheet; 221, second recessed portion. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0038] Reference Figure 1 As shown, the utility model discloses a diaphragm, including a diaphragm body 10 and a protrusion 11. The diaphragm body 10 belongs to the prior art, and the diaphragm body 10 is used to separate the positive electrode plate 21 and the negative electrode plate 22 to prevent the two poles from contacting and short-circuiting. Those skilled in the art can set the specific size, material, etc. of the diaphragm body 10 according to actual needs. Preferably, the material of the diaphragm body 10 is set to any one of PE (polyethylene, abbreviation of Polyethylene), PP (polypropylene, abbreviation of polypropylene), PE / PP, PP / PE / PE.

[0039] The raised portion 11 is connected to the diaphragm body 10; those skilled in the art can set the specific connection method of the raised portion 11 and the diaphragm body 10 according to actual needs, such as integral molding, spraying and rolling, etc. The raised portion 11 is used to cooperate with the pole piece; specifically, the raised portion 11 is used to cooperate with the positive pole piece 21 provided with an etching channel or / and the negative pole piece 22 provided with an etching channel.

[0040] Those skilled in the art can set the number of specific protrusions 11 according to actual needs. For example, only one protrusion 11 is set at a certain position of the diaphragm body 10 that can correspond to the etched concave portion of the pole piece, so that the protrusion 11 is matched with the etched concave portion of the pole piece. Alternatively, multiple protrusions 11 are set on the diaphragm body 10, so that the multiple protrusions 11 are matched with the multiple etched concave portions of the pole piece.

[0041] When there are multiple protrusions 11, those skilled in the art can set the specific positions of the protrusions 11 according to actual needs. Figure 1 As shown, a plurality of protrusions 11 can be simultaneously provided on one of the surfaces of the diaphragm body 10 along its thickness direction, so that the side surface of the diaphragm body 10 provided with the protrusions 11 can be matched with the etched concave portion of the pole piece through the protrusions 11. Figure 2 As shown, a plurality of protrusions 11 can also be respectively arranged on two surfaces of the diaphragm body 10 along its own thickness direction, so that the surfaces on both sides of the diaphragm body 10 along its own thickness direction can be matched with the etched concave portions of the corresponding pole pieces through the protrusions 11.

[0042] When the diaphragm body 10 is provided with protrusions 11 on both surfaces along its thickness direction, Figure 2 As shown, the protrusions 11 located on the two surfaces of the diaphragm body 10 can correspond one to one to facilitate positioning and assembly; Figure 3 As shown, the protrusions 11 located on the two surfaces of the diaphragm body 10 can be staggered to reduce the positioning accuracy requirements and reduce the production difficulty.

[0043] Those skilled in the art can also set the cross-sectional shape and size of the specific protrusion 11 according to actual needs. It should be noted that the cross section of the protrusion 11 in the present application refers to the cross section perpendicular to the extension direction of the protrusion 11. Specifically, the protrusion 11 can be set to have a size in the first direction D1 that remains unchanged regardless of how it changes along the second direction D2. For example, referring to Figure 2 As shown, the cross-sectional shape is set to be a rectangle, a square, etc. Alternatively, the protrusion 11 is set so that its size in the first direction D1 changes with the change of the second direction D2, for example, referring to Figure 4 , Figure 5 and Figure 6As shown, the cross-sectional shape is set to a trapezoid, a triangle, a combination of a square and a half ellipse, etc.

[0044] Regardless of how the number, position, shape, and size of the protrusions 11 change, the diaphragm described in the utility model, by providing the protrusions 11 on the diaphragm body 10, enables the diaphragm body 10 provided with the protrusions 11 to be concave-convexly matched with the pole piece including the etched concave portion. Since the diaphragm body 10 can be concave-convexly matched with the pole piece including the etched concave portion through the protrusions 11, firstly, the problem of unevenness of the laser etched surface of the pole piece can be alleviated, and the long cycle capacity of the battery and the service life of the battery can be improved. Secondly, it can prevent the problem of the pole piece from falling off and the powder moving inside the battery, prevent the occurrence of short circuits and other problems, and improve the safety performance of the battery. In addition, the contact area between the diaphragm body 10 and the pole piece is increased, avoiding the problem of a large gap between the etched concave portion of the pole piece and the diaphragm body 10, avoiding the low capacity phenomenon, and improving the capacity retention rate of the battery. Finally, the diaphragm body 10 can be compounded with the pole piece in advance through the protrusions 11, effectively improving the production and preparation efficiency.

[0045] In some embodiments of the diaphragm described in the utility model, a plurality of raised portions 11 are provided. A plurality of raised portions 11 are arranged in sequence and spaced apart along the length direction of the diaphragm body 10, or a plurality of raised portions 11 are arranged in sequence and spaced apart along the width direction of the diaphragm body 10. Among them, the interval between adjacent raised portions 11 is set to 100μm to 600μm. Specifically, when the interval between adjacent raised portions 11 is less than 100μm, the interval between the two raised portions 11 is too small, the difficulty of assembly increases, and it is difficult to cooperate with the etched recess. When the interval between adjacent raised portions 11 is greater than 600μm, the interval between the two raised portions 11 is too large. After the assembly with the pole piece is completed, the raised portion 11 and the etched recess on the pole piece will be difficult to cooperate due to the large interval, affecting the corresponding effect. When the interval between adjacent protrusions 11 is set at 100 μm to 600 μm, the difficulty of assembly can be reduced while ensuring the protrusions 11 and the etched concave parts are matched, improving the rate performance, capacity retention rate and long cycle capacity of the battery. Those skilled in the art can set specific intervals according to actual needs, such as 100 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, 550 μm, 600 μm, etc.

[0046] In some embodiments of the diaphragm described in the utility model, the protrusion 11 is a coating of any one of CMC (carboxymethyl cellulose), PVDF (polyvinylidene difluoride), POA (2-(pyridin-3-yloxy)ethylamine), PMMA (polymethyl methacrylate), and aramid fiber. The protrusion 11 made of the above materials is sticky and can further enhance the connection between the protrusion 11 and the etched concave part under the premise of matching the protrusion and concave of the protrusion 11, thereby improving the rate performance, capacity retention rate and long cycle capacity of the battery.

[0047] Preferably, when preparing the raised portion 11, the slurry is firstly evenly atomized and sprinkled on the diaphragm body 10 by rotor spraying, which is referred to as an atomized diaphragm. Subsequently, it is transferred and coated on the atomized diaphragm by a gravure roller, and then passed through an oven to form an alternating raised adhesive layer, thereby obtaining the diaphragm body 10 including the raised portion 11. It is also possible to coat the atomized diaphragm with an equally spaced extruded adhesive layer slurry, and then pass through an oven to form an alternating raised adhesive layer, thereby obtaining the diaphragm body 10 including the raised portion 11. Among them, the gravure roller refers to a roller engraved with corresponding stripes along TD; the material movement direction is RD (rolling direction), the normal direction of the surface where the material contacts the rolling tool is ND (normal direction), and the direction perpendicular to RD and ND is TD (transverse direction).

[0048] Reference Fig.11 As shown, the utility model also discloses a battery, including a positive electrode sheet 21, a negative electrode sheet 22 and a diaphragm described in any of the above embodiments, and the diaphragm body 10 is located between the positive electrode sheet 21 and the negative electrode sheet 22. Since the battery includes the diaphragm described in the above embodiment, the battery also has the beneficial effects of the diaphragm, which will not be repeated. The battery can be set as a cylindrical battery, a square battery, a soft pack battery, etc.

[0049] The positive electrode sheet 21 has an etched channel on its surface along the thickness direction of the diaphragm body 10. The etched channel provided on the positive electrode sheet 21 is called a first recess 211. The first recess 211 is used to match the protrusion 11. In order to ensure the wettability of the electrolyte, a plurality of first recesses 211 are usually provided. Those skilled in the art can set the position of the first recess 211 on the positive electrode sheet 21 according to actual needs. Figure 7As shown, the plurality of first recesses 211 can be provided only on any one surface of the positive electrode sheet 21 along the thickness direction of the diaphragm body 10, so that the side surface of the positive electrode sheet 21 provided with the first recess 211 can be matched with the protrusion 11 of the diaphragm body 10 through the first recess 211; Figure 8 As shown, a plurality of first recesses 211 can be respectively arranged on the two surfaces of the positive electrode sheet 21 along the thickness direction of the diaphragm body 10, so that the surfaces of the positive electrode sheet 21 on both sides along the thickness direction of the diaphragm body 10 can be matched with the corresponding protrusions 11 of the diaphragm body 10 through the first recesses 211. When the first recesses 211 are arranged on both surfaces of the positive electrode sheet 21 along its own thickness direction, the first recesses 211 located on the two surfaces of the positive electrode sheet 21 can correspond one to one to facilitate positioning and assembly; or, the first recesses 211 located on the two surfaces of the positive electrode sheet 21 can be staggered to reduce the requirements for positioning accuracy and reduce the difficulty of production. Correspondingly, refer to Fig.11 , Fig.13 , Fig.14 and Fig.15 As shown, those skilled in the art can also set the cross-sectional shape of the first recess 211 according to actual needs. Preferably, the cross-sectional shape of the first recess 211 is the same as the cross-sectional shape of the protrusion 11 .

[0050] The negative electrode sheet 22 has an etched channel on its surface along the thickness direction of the diaphragm body 10. The etched channel provided on the negative electrode sheet 22 is called a second recess 221. The second recess 221 is used to match the protrusion 11. In order to ensure the wettability of the electrolyte, a plurality of second recesses 221 are usually provided. Those skilled in the art can set the position of the second recess 221 on the negative electrode sheet 22 according to actual needs. Fig. 9 As shown, the plurality of second recesses 221 can be provided only on any one surface of the negative electrode sheet 22 along the thickness direction of the diaphragm body 10, so that the side surface of the negative electrode sheet 22 provided with the second recesses 221 can be matched with the raised portion 11 of the diaphragm body 10 through the second recesses 221; Fig.10 As shown, a plurality of second recesses 221 can be respectively arranged on the two surfaces of the negative electrode sheet 22 along the thickness direction of the diaphragm body 10, so that the surfaces of the negative electrode sheet 22 on both sides along the thickness direction of the diaphragm body 10 can be matched with the corresponding protrusions 11 of the diaphragm body 10 through the second recesses 221. When the second recesses 221 are arranged on both surfaces of the negative electrode sheet 22 along its own thickness direction, the second recesses 221 located on the two surfaces of the negative electrode sheet 22 can correspond one to one to facilitate positioning and assembly; or, the second recesses 221 located on the two surfaces of the negative electrode sheet 22 can be staggered to reduce the requirements for positioning accuracy and reduce the difficulty of production. Correspondingly, refer to Fig.11 , Fig.13 , Fig.14 and Fig.15 As shown, those skilled in the art can also set the cross-sectional shape of the second recess 221 according to actual needs. Preferably, the cross-sectional shape of the second recess 221 is the same as the cross-sectional shape of the protrusion 11 .

[0051] When assembling the pole piece and diaphragm, refer to Fig.15 As shown, only the positive electrode sheet 21 with the first recess 211 can be assembled with the diaphragm body 10 with the protrusion 11, while the negative electrode sheet 22 is not provided with the second recess 221 and can be directly assembled. Fig.16 As shown, only the negative electrode sheet 22 provided with the second recess 221 can be assembled with the diaphragm body 10 provided with the protrusion 11, while the positive electrode sheet 21 is not provided with the first recess 211 and is directly assembled. Fig.17 As shown, the positive electrode sheet 21 provided with the first recess 211 , the negative electrode sheet 22 provided with the second recess 221 , and the diaphragm body 10 provided with the protrusion 11 can also be assembled.

[0052] Reference Fig.12 As shown, in some embodiments of the battery of the present invention, along the first direction D1, the size W of the first recess 211 is 1 and the size W of the second recess 221 2 are all set to 0-100 μm. Along the second direction D2, the size H of the first concave portion 211 1 and the size H of the second recess 221 2 The spacing between adjacent first recesses 211 is set to 100 μm to 600 μm, and the spacing between adjacent second recesses 221 is set to 100 μm to 600 μm, so as to fit the protrusion 11 on the diaphragm body 10 .

[0053] Preferably, when preparing the first recess 211 and the second recess 221, the pole piece is coated on the foil, and an etching channel is prepared along the coated pole piece TD by laser scanning etching technology. Laser scanning etching technology belongs to the prior art, and its specific working principle is not repeated; preferably, an ultra-short strong laser pulse is used, the pulse energy is 1 to 10 μJ, the laser power is 1 to 10 W, the laser scanning speed is 1 to 100 mm / s, and the etching time is 0.2 to 10 s. Preferably, when assembling the pole piece and the diaphragm, the corresponding etched channel is stabilized with the raised portion 11 and hot pressed to shape. The hot pressing parameter pressure is 0 to 100 tons, and the hot pressing time is 5 to 30 s; then, the pole piece is recombined to assemble the battery cell.

[0054] Further, see Fig.12As shown, in some embodiments of the battery of the present invention, the cross-sectional shape of the protrusion 11 is rectangular. Along the first direction D1, the dimension y of the protrusion 11 and the dimension W of the first recess 211 are 1 Meets 0.85W 1 ≤y≤1.00W 1 When y is less than 0.85W 1 When y is greater than 1.00W, the size of the protrusion 11 along the first direction D1 is too small, and it is difficult to ensure the connection effect between the protrusion 11 and the first recess 211; 1 When 0.85W 1 ≤y≤1.00W 1 When the battery is assembled, the protrusion 11 and the first recess 211 can be easily assembled, while the connection effect after assembly is taken into consideration, thereby effectively extending the battery cycle life, improving the battery safety performance, and improving the battery capacity retention rate.

[0055] Further, see Fig.12 As shown, in some embodiments of the battery of the present invention, the cross-sectional shape of the protrusion 11 is rectangular. Along the second direction D2, the dimension x of the protrusion 11 and the dimension H of the first recess 211 are 1 Meet 0.05H 1 ≤x≤0.30H 1 When x is less than 0.05H 1 When x is greater than 0.30H, the size of the protrusion 11 along the second direction D2 is too small, and it is difficult to ensure the connection effect between the protrusion 11 and the first recess 211; 1 When 0.05H 1 ≤x≤0.30H 1 When the protrusion 11 and the first concave portion 211 are connected, the assembly can be facilitated, the production efficiency can be improved, and the connection effect after the assembly is completed can be taken into account, thereby effectively extending the battery cycle life, improving the battery safety performance, and improving the battery capacity retention rate. Preferably, the size requirements of the protrusion 11 in the first direction D1 and the second direction D2 are met at the same time to obtain the best effect.

[0056] Further, see Fig.12 As shown, in some embodiments of the battery of the present invention, the cross-sectional shape of the protrusion 11 is rectangular, and along the first direction D1, the size y of the protrusion 11 and the size W of the second recess 221 are equal to 2 Meets 0.85W 2 ≤y≤1.00W 2When y is less than 0.85W 2 When y is greater than 1.00W, the size of the protrusion 11 along the first direction D1 is too small, and it is difficult to ensure the connection effect between the protrusion 11 and the second concave portion 221; 2 When the size of the protrusion 11 along the first direction D1 is too large, it is difficult to achieve the matching assembly of the protrusion 11 and the second recess 221. 2 ≤y≤1.00W 2 When the battery is assembled, the protrusion 11 and the second recess 221 can be easily assembled, while the connection effect after assembly is taken into consideration, thereby effectively extending the battery cycle life, improving the battery safety performance, and improving the battery capacity retention rate.

[0057] Further, see Fig.12 As shown, in some embodiments of the battery of the present invention, the cross-sectional shape of the protrusion 11 is rectangular. Along the second direction D2, the dimension x of the protrusion 11 and the dimension H of the second recess 221 are 2 Meet 0.05H 2 ≤x≤0.30H 2 When x is less than 0.05H 2 When x is greater than 0.30H, the size of the protrusion 11 along the second direction D2 is too small, and it is difficult to ensure the connection effect between the protrusion 11 and the second recess 221; 2 When 0.05H 2 ≤x≤0.30H 2 When the protrusion 11 and the second concave portion 221 are connected, the assembly between the protrusion 11 and the second concave portion 221 can be facilitated, the production efficiency can be improved, and the connection effect after the assembly is completed can be taken into account, thereby effectively extending the battery cycle life, improving the battery safety performance, and improving the battery capacity retention rate. Preferably, the size requirements of the protrusion 11 in the first direction D1 and the second direction D2 are met at the same time to obtain the best effect.

[0058] Next, the first sample cell, the second sample cell and the third sample cell are selected to respectively detect the Hi-pot defect rate, the long cycle attenuation ratio, the rate charge constant current ratio and the rate discharge capacity retention rate of each sample cell.

[0059] The positive electrode plates of the three sample cells are all made of NMC655 ternary material, with a loading of 96% (indicating the mass proportion of the positive or negative active material in the corresponding formula) and a compaction of 3.40; the negative electrode plates are all made of graphite material, with a loading of 97% and a compaction of 1.65. 1 and W 2 All are set to 100 μm, H 1 and H2 The thickness of the electrode and the diaphragm are all set to 10μm; the diaphragm includes 7μm PE + 3μm PVDF + 3μm PVDF; the electrode and the diaphragm are stacked to form a sample battery cell. In the second sample battery cell, the battery cell structure is referenced Fig.11 As shown, only the positive electrode sheet 21 is provided with the first recess 211. 1 Set to 100 μm, H 1 The diaphragm is set to 10μm; the convex portion 11 is provided on only one side of the diaphragm close to the positive electrode sheet 21, and the diaphragm includes 7μm PE + 3 / 3.5μm PVDF + 3μm PVDF, wherein the 3 / 3.5μm PVDF is set on the positive electrode sheet 21. In the third sample battery cell, the battery cell structure refers to Fig.17 As shown, the positive electrode sheet 21 is provided with a first recess 211, the negative electrode sheet 22 is provided with a second recess 221, and the surfaces of both sides of the diaphragm are provided with protrusions 11; 1 and W 2 All are set to 100 μm, H 1 and H 2 All are set to 10μm; the separator includes 7μm PE+3 / 5μm PVDF+3 / 5μm PVDF.

[0060] The Hi-pot defect rate is used to indicate whether the sample battery cell has an internal resistance short circuit; when performing the Hi-pot test, use an insulation tester and set its output voltage to 200V to obtain the Hi-pot defect rate.

[0061] When performing the cycle decay test, first charge to 4.25V with a constant current of 1C, then charge to 0.05C with a constant voltage; after standing for 30 minutes, discharge to 2.8V with a constant current of 1C. The capacity at this time is taken as the initial capacity C 0 Repeat the above steps and record the capacity C after the corresponding number of cycles. n , n is the number of cycles, and the cycle capacity decay rate is [1-(C n / C 0 )^(1 / n)]×100%. The value of n was set to 100, 300 and 800 respectively for cycle tests to obtain the corresponding cycle attenuation rates.

[0062] When performing the constant current ratio test, first charge NC to 4.2V with constant current, where N is the selected rate value, and the capacity is recorded as cap 1 Then charge at a constant voltage until the current is no more than 0.05C, and record the capacity as cap 2 , constant current ratio is (cap 1 / cap 2 )×100%, the higher the value, the better the charging capacity. Set the value of N to 1 and 3 respectively to perform constant current ratio test and obtain the corresponding constant current ratio.

[0063] When testing the discharge capacity retention rate, first charge to 4.25V with a 1 / 3C constant current and then charge to 0.05C with a constant voltage. After standing for 30 minutes, discharge to 2.8V with a 1 / 3C constant current. a The constant capacity is then measured using 1 / 3C constant current and constant voltage, and then discharged to 2.8V using NC, and the discharge capacity C at different rates is recorded. b , the discharge capacity retention rate is (C b / C a )×100%. The constant current ratio test was performed by setting the value of N to 1 and 3 respectively to obtain the corresponding discharge capacity retention rate.

[0064] The test results of each sample battery cell are shown in Table 1.

[0065] Table 1 Sample battery test results

[0066] The first sample cell The second sample cell The third sample cell Hi-pot defect 23％ 1.50％ 2.80％ 100cyc cycle decay 2.3％ 0.60％ 0.80％ 300cyc cycle decay 7.60％ 1.20％ 1.20％ 800cyc cycle decay 12.20％ 5.20％ 5.80％ 1200cyc cycle decay 26.40％ 7.60％ 8.10％ 1C charging constant current ratio 92％ 96％ 95％ 3C charging constant current ratio 82％ 93％ 90％ 1C discharge capacity retention rate 92％ 98％ 95％ 3C discharge capacity retention rate 72％ 90％ 88％

[0067] With reference to the test results in Table 1, it can be seen that the diaphragm described in the utility model can effectively prevent internal short circuits, improve battery safety performance, extend battery cycle life, and enhance battery capacity retention rate.

[0068] The utility model also discloses an electrical device, comprising the battery described in any one of the above embodiments.

[0069] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention of the utility model.

Claims

1. A diaphragm, characterized in that: include: Diaphragm body (10); A raised portion (11), the raised portion (11) is connected to the diaphragm body (10), and the raised portion (11) is used to cooperate with a pole piece.

2. The diaphragm according to claim 1, characterized in that: There are a plurality of protrusions (11), and the plurality of protrusions (11) are arranged in sequence and spaced apart along the length direction of the diaphragm body (10), or the plurality of protrusions (11) are arranged in sequence and spaced apart along the width direction of the diaphragm body (10), and the interval between adjacent protrusions (11) is set to 100 μm to 600 μm.

3. The diaphragm according to claim 1, characterized in that: The protrusion is coated with any one of CMC, PVDF, POA, PMMA and aramid.

4. A battery, characterized in that: It comprises a positive electrode sheet (21), a negative electrode sheet (22) and a diaphragm according to any one of claims 1 to 3, wherein the diaphragm body (10) is located between the positive electrode sheet (21) and the negative electrode sheet (22); The positive electrode plate (21) has a first recess (211) on its surface along the thickness direction of the diaphragm body (10), and the first recess (211) is used to match the protrusion (11); the negative electrode plate (22) has a second recess (221) on its surface along the thickness direction of the diaphragm body (10), and the second recess (221) is used to match the protrusion (11).

5. The battery according to claim 4, characterized in that: Along the first direction (D1), the size W1 of the first recess (211) and the size W2 of the second recess (221) are both set to 0 to 100 μm; along the second direction (D2), the size H1 of the first recess (211) and the size H2 of the second recess (221) are both set to 0 to 40 μm.

6. The battery according to claim 5, characterized in that: The cross-sectional shape of the protrusion (11) is rectangular, and along the first direction (D1), the dimension y of the protrusion (11) and the dimension W1 of the first recess (211) satisfy 0.85W1≤y≤1.00W1.

7. The battery according to claim 5 or 6, characterized in that: The cross-sectional shape of the protrusion (11) is rectangular, and along the second direction (D2), the dimension x of the protrusion (11) and the dimension H1 of the first recess (211) satisfy 0.05H1≤x≤0.30H1.

8. The battery according to claim 5, characterized in that: The cross-sectional shape of the protrusion (11) is rectangular, and along the first direction (D1), the dimension y of the protrusion (11) and the dimension W2 of the second recess (221) satisfy 0.85W2≤y≤1.00W2.

9. The battery according to claim 5 or 8, characterized in that: The cross-sectional shape of the protrusion (11) is rectangular, and along the second direction (D2), the dimension x of the protrusion (11) and the dimension H2 of the second recess (221) satisfy 0.05H2≤x≤0.30H2.

10. An electrical device, characterized in that: Comprising a battery as claimed in any one of claims 4 to 9.

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