Battery and electric device

Abstract

The utility model provides a kind of battery and electric device, wherein battery includes: shell, at least one end of shell is provided with opening;Battery cell, setting in shell;Cover plate, cover plate is covered in opening, cover plate includes cover plate body and the step portion being set to the periphery of cover plate body, shell has the end face at opening, step portion has the lap joint surface of lap joint on end face, overlap area is formed between lap joint surface and end face, end face is connected with lap joint surface, end face is plane, the width of overlap area along the direction parallel to end face is a mm, the distance between lap joint surface and the negative pole piece of battery cell along the direction perpendicular to end face is b mm, wherein, a x b satisfies:1.2mm 2 ≦(a x b)≦15mm 2 The technical scheme of the present application effectively solves the problem of easily causing thermal runaway in related technologies.

Description

Technical Field

[0001] This utility model relates to the field of batteries, and more specifically, to a battery and an electrical device. Background Technology

[0002] Welding between the casing and the cover plate is a critical step in the battery assembly process to ensure sealing and structural stability, but this process also carries the potential risk of thermal runaway.

[0003] During welding, high-temperature energy is concentrated at the connection between the shell and the cover plate. If the operation is not properly controlled, the heat will be conducted along the shell and / or cover plate to the inside of the cell, which can easily cause thermal decomposition of the materials inside the cell and thus easily lead to thermal runaway. Utility Model Content

[0004] The main objective of this invention is to provide a battery and electrical device to solve the problem of thermal runaway in related technologies.

[0005] To achieve the above objectives, according to one aspect of the present invention, a battery is provided, comprising: a casing, at least one end of which has an opening; a battery cell disposed within the casing; and a cover plate covering the opening, the cover plate including a cover plate body and a stepped portion disposed on the outer periphery of the cover plate body, the casing having an end face located at the opening, the stepped portion having an overlapping surface overlapping the end face, the overlapping surface and the end face forming an overlapping area, the end face being connected to the overlapping surface, the end face being planar, the width of the overlapping area in a direction parallel to the end face being a mm, and the distance between the overlapping surface in a direction perpendicular to the end face and the negative electrode plate of the battery cell being b mm, wherein a × b satisfies: 1.2 mm. 2 ≦(a×b)≦15mm 2 .

[0006] According to another aspect of the present invention, an electrical device is provided, including a battery, wherein the battery is the aforementioned type of battery.

[0007] According to the technical solution of this utility model, the battery includes: a casing, a battery cell, and a cover plate. At least one end of the casing has an opening. The battery cell is disposed inside the casing. The cover plate covers the opening and includes a cover plate body and a stepped portion disposed on the outer periphery of the cover plate body. The casing has an end face located at the opening, and the stepped portion has an overlapping surface that overlaps with the end face. An overlapping area is formed between the overlapping surface and the end face, and the end face is connected to the overlapping surface. The end face is planar, and the width of the overlapping area in the direction parallel to the end face is a mm. The distance between the overlapping surface in the direction perpendicular to the end face and the negative electrode plate of the battery cell is b mm, where a × b satisfies: 1.2 mm. 2 ≦(a×b)≦15mm 2 Because a×b in this application satisfies 1.2mm. 2≦(a×b)≦15mm 2 The size range allows for effective control of the distance between the welding position and the battery cell, effectively reducing the possibility of thermal runaway. Therefore, the technical solution of this application effectively solves the problem of easily causing thermal runaway in related technologies. Attached Figure Description

[0008] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0009] Figure 1 A three-dimensional structural schematic diagram of an embodiment of the battery according to the present invention is shown;

[0010] Figure 2 It shows Figure 1 A cross-sectional view of the battery after it has been cut along the length of the casing;

[0011] Figure 3 It shows Figure 2 An enlarged schematic diagram of point A on the battery;

[0012] Figure 4 It shows Figure 2 An enlarged schematic diagram showing the dimensional relationships between the components at point A of the battery;

[0013] Figure 5 It shows Figure 4 An enlarged schematic diagram of point B on the battery.

[0014] The above figures include the following reference numerals:

[0015] 10. Shell; 11. Opening; 12. End face; 13. Long side; 14. Short side; 15. Plate; 16. Overlapping area; 17. Welding area;

[0016] 20. Battery cell; 22. Negative electrode; 23. Positive electrode;

[0017] 30. Cover plate; 31. Stepped part; 311. Overlapping surface; 312. Overlapping part; 313. Insertion part; 314. Chamfer; 32. Cover plate body. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0021] Here, we will first describe the relevant technology of the battery in the specific implementation method. The battery includes: a casing, a cell, and a cover plate. The cover plate is provided with a stepped portion, and a step is provided on the casing at a position corresponding to the stepped portion. Due to the existence of the step, the distance between the cover plate and the casing is large, and the welding heat has little impact on the cell. However, the utilization rate of the internal space of the casing is low, and the energy density of the battery is also reduced.

[0022] To address the aforementioned problems, this application provides a battery, such as... Figures 1 to 5As shown, an embodiment of the battery includes: a casing 10, a battery cell 20, and a cover plate 30. At least one end of the casing 10 has an opening 11. The battery cell 20 is disposed within the casing 10. The cover plate 30 covers the opening 11 and includes a cover plate body 32 and a stepped portion 31 disposed on the outer periphery of the cover plate body 32. The casing 10 has an end face 12 located at the opening 11. The stepped portion 31 has an overlapping surface 311 that overlaps with the end face 12. An overlapping area 16 is formed between the overlapping surface 311 and the end face 12. The end face 12 is connected to the overlapping surface 311. The end face 12 is planar. The width of the overlapping area 16 in the direction X parallel to the end face 12 is a mm. The distance between the overlapping surface 311 in the direction Y perpendicular to the end face 12 and the negative electrode plate 22 of the battery cell 20 is b mm, where a × b satisfies: 1.2 mm. 2 ≦(a×b)≦15mm 2 .

[0023] It should be noted that mm in this application means millimeter; a×b and (a×b) both represent the product of a and b.

[0024] In the embodiment of the battery application, since end face 12 is flat, the casing of this embodiment eliminates the step, allowing the battery cell to be positioned closer to the cover plate. However, this can easily lead to heat transfer from the welding of the cover plate and casing to the battery cell. But in this embodiment, by comprehensively controlling a×b, a = 1.2mm... 2 ≦(a×b)≦15mm 2 Within this range, the distance between the welding position and the battery cell can be effectively controlled, effectively reducing the possibility of thermal runaway. Thus, a×b satisfies the 1.2mm requirement. 2 ≦(a×b)≦15mm 2 The size range takes into account welding reliability while avoiding the transfer of welding heat to the battery cell.

[0025] The welding methods described above can include laser welding, resistance welding, or ultrasonic welding. The lap surface 311 described above can be an annular surface or a straight surface.

[0026] It should be noted that the integrated control a×b satisfies 1.2mm. 2 ≦(a×b)≦15mm 2 When considering the size range, a×b should not be too small; for example, if it is less than 1.2mm... 2 The size is still small, the distance between the lap surface and the cell is short, and the width of the lap surface is small, making it easy for welding heat to be transferred to the cell, causing the cell to be overheated and easily damaged; in addition, a×b cannot be too large, if it is more than 15mm 2 It is also large, with low utilization of the internal space of the casing, resulting in reduced battery energy density.

[0027] Preferably, a×b is 1.2mm. 2Or 1.4mm 2 Or 1.6mm 2 Or 1.8mm 2 Or 2mm 2 Or 2.2mm 2 Or 2.4mm 2 Or 2.6mm 2 Or 2.8mm 2 Or 3mm 2 Or 3.2mm 2 Or 3.4mm 2 Or 3.6mm 2 Or 3.8mm 2 Or 4mm 2 Or 4.2mm 2 Or 4.4mm 2 Or 4.6mm 2 Or 4.8mm 2 Or 5mm 2 Or 5.2mm 2 Or 5.4mm 2 Or 5.6mm 2 Or 5.8mm 2 Or 6mm 2 Or 6.2mm 2 Or 6.4mm 2 Or 6.6mm 2 Or 6.8mm 2 Or 7mm 2 Or 7.2mm 2 Or 7.4mm 2 Or 7.6mm 2 Or 7.8mm 2 Or 8mm 2 Or 8.2mm 2 Or 8.4mm 2 Or 8.6mm 2 Or 8.8mm 2 Or 9mm 2 Or 9.2mm 2 Or 9.4mm 2 Or 9.6mm 2 Or 9.8mm 2 Or 10mm 2 Or 10.2mm 2 Or 10.4mm 2 Or 10.6mm 2 Or 10.8mm 2 Or 11mm 2 Or 11.2mm 2 Or 11.4mm2 Or 11.6mm 2 Or 11.8mm 2 Or 12mm 2 Or 12.2mm 2 Or 12.4mm 2 Or 12.6mm 2 Or 12.8mm 2 Or 13mm 2 Or 13.2mm 2 Or 13.4mm 2 Or 13.6mm 2 Or 13.8mm 2 Or 14mm 2 Or 14.2mm 2 Or 14.4mm 2 Or 14.6mm 2 Or 14.8mm 2 Or 15mm 2 .

[0028] like Figures 3 to 5 As shown, end face 12 is welded to overlapping surface 311 to form a welding area 17 between end face 12 and overlapping surface 311. To reduce the risk of heat transfer to the battery cell, the welding area 17 and the inner edge of the casing 10 are spaced apart, and b satisfies: 3.5mm≦b≦13mm. Thus, by further controlling b to satisfy: 3.5mm≦b≦13mm, the internal space utilization of the casing 10 can be improved, thereby increasing the battery energy density; at the same time, heat transfer from the battery cell to the battery cell 20 is avoided.

[0029] The preferred thickness of b is 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, 10.5mm, 11mm, 11.5mm, 12mm, 12.5mm, or 13mm.

[0030] like Figures 3 to 5 As shown, the welding area 17 extends to the inner edge of the housing 10, and b satisfies: 4mm ≤ b ≤ 15mm. Thus, by extending the welding area 17 to the inner edge of the housing 10, the connection strength between the housing 10 and the cover plate 30 is improved. Furthermore, by controlling b to satisfy 4mm ≤ b ≤ 15mm, heat is prevented from affecting the battery cell. Preferably, b is 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15mm.

[0031] like Figures 3 to 5 As shown, the ratio of the width of the welding area 17 to the width of the end face 12 is greater than or equal to 0.8 and less than or equal to 2. This dimensional range ensures the welding strength of the welding area 17 while preventing excessive heat from being transferred to the battery cell 20, which could potentially damage the cell. The preferred ratio is 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.

[0032] like Figure 3 and Figure 4 As shown, the battery cell 20 includes a negative electrode 22 and a positive electrode 23. In the height direction Y of the battery cell 20, the negative electrode 22 protrudes beyond the positive electrode 23, and b satisfies: 3.5mm≦b≦16mm. Because the negative electrode 22 protrudes beyond the positive electrode 23, and b is controlled to satisfy: 3.5mm≦b≦16mm, heat transfer to the positive electrode 23 and the negative electrode 22 is avoided.

[0033] Preferably, b is 3.5mm or 4mm or 4.5mm or 5mm or 5.5mm or 6mm or 6.5mm or 7mm or 7.5mm or 8mm or 8.5mm or 9mm or 9.5mm or 10mm or 10.5mm or 11mm or 11.5mm or 12mm or 12.5mm or 13mm or 13.5mm or 14mm or 14.5mm or 15mm or 15.5mm or 16mm.

[0034] like Figure 3 and Figure 4 As shown, the battery cell 20 includes a positive electrode 23. In the direction Y perpendicular to the end face 12, the distance H1 between the overlapping surface 311 and the positive electrode 23 is greater than or equal to 4.7 mm and less than or equal to 18 mm. In this way, the distance between the positive electrode 23 and the overlapping surface 311 is controlled within 4.7 mm and less than or equal to 18 mm to avoid heat transfer to the positive electrode 23.

[0035] Preferably, the distance H1 between the overlapping surface 311 and the positive electrode plate 23 is 4.7mm, 4.9mm, 5mm, 5.3mm, 5.5mm, 5.7mm, 5.9mm, 6mm, 6.3mm, 6.5mm, 6.7mm, 6.9mm, 7mm, 7.3mm, 7.5mm, 7.7mm, 7.9mm, 8mm, 8.3mm, 8.5mm, 8.7mm, 8.9mm, 9mm, 9.3mm, 9.5mm, 9.7mm, 9.9mm, 10mm, 10.3mm, 10.5mm, 10.7mm, 10.9mm, 11mm, 11.3mm, or 1 1.5mm or 11.7mm or 11.9mm or 12mm or 12.3mm or 12.5mm or 12.7mm or 12.9mm or 13mm or 13.3mm or 13.5mm or 13.7mm or 13.9mm or 14mm or 14.3mm or 14.5mm or 14.7mm or 14.9mm or 15mm or 15.3mm or 15.5mm or 15.7mm or 15.9mm or 16mm or 16.3mm or 16.5mm or 16.7mm or 16.9mm or 17mm or 17.3mm or 17.5mm or 17.7mm or 17.9mm or 18mm.

[0036] like Figure 3 and Figure 4 As shown, the stepped portion 31 includes an overlapping portion 312 that overlaps with the end face 12 and an insertion portion 313 connected to the overlapping portion 312. At least a portion of the insertion portion 313 is embedded in the housing 10. The ratio between the dimension of the insertion portion 313 in the direction Y perpendicular to the end face 12 and the thickness of the cover plate 30 is greater than or equal to 0.45 and less than or equal to 0.85. By controlling the thickness ratio of the insertion portion 313, welding heat is further prevented from being transferred to the battery cell 20, and the portion of the cover plate 30 other than the stepped portion 31 is further prevented from being welded through during welding of the cover plate 30 and the housing 10.

[0037] Preferably, the ratio between the dimension of the insertion part 313 in the direction Y perpendicular to the end face 12 and the thickness of the cover plate 30 is preferably 0.45 or 0.5 or 0.55 or 0.6 or 0.65 or 0.7 or 0.75 or 0.8 or 0.85.

[0038] like Figure 3 and Figure 4As shown, the insertion part 313 is provided with a chamfer 314, and the angle c between the extension line of the chamfer 314 and the extension line of the cover plate is greater than or equal to 30 degrees and less than or equal to 60 degrees. The chamfer 314 facilitates the insertion part 313 from the opening 11 into the housing 10. The size of the chamfer 314 should not be less than 30 degrees, and a larger size of the chamfer 314 can also reduce heat transfer.

[0039] Preferably, the chamfer 314 has a size of 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, or 60 degrees.

[0040] like Figure 3 and Figure 4 As shown, the ratio between 'a' and the wall thickness of the housing 10 is greater than or equal to 0.5 and less than or equal to 1. Since this ratio satisfies the condition of greater than or equal to 0.5 and less than or equal to 1, the connection area for welding the end face 12 and the lap surface 311 is guaranteed, ensuring the reliability of the weld. Furthermore, sufficient thermal resistance is ensured between the end face 12 and the lap surface 311, reducing the rate at which heat is conducted along the wall of the housing 10 to the cell 20, thereby reducing the impact of welding heat transfer on the cell 20.

[0041] Preferably, the ratio between a and the wall thickness of the housing 10 is 0.5, 0.6, 0.7, 0.8, 0.9, or 1.

[0042] like Figure 3 and Figure 4 As shown, the distance H2 between the inner wall of the casing 10 and the cell 20 is greater than or equal to 2 mm and less than or equal to 3.5 mm. This dimensional range allows for full utilization of the internal space of the casing, avoiding a reduction in battery energy density.

[0043] Preferably, the distance H2 between the inner wall of the housing 10 and the battery cell 20 is 2mm or 2.1mm or 2.2mm or 2.3mm or 2.4mm or 2.5mm or 2.6mm or 2.7mm or 2.8mm or 2.9mm or 3mm or 3.1mm or 3.2mm or 3.3mm or 3.4mm or 3.5mm.

[0044] like Figure 3 and Figure 4 As shown, the outer edge of the cover plate 30 is lower than the outer wall surface of the housing 10. This allows for welding operations between the end face 12 and the overlapping surface 311 in the direction Y, perpendicular to the end face 12. Alternatively, the outer edge of the cover plate 30 is flush with the outer wall surface of the housing 10, allowing for welding operations between the end face 12 and the overlapping surface 311 in either the width or length direction. This increases the selectivity of the welding direction and facilitates flexible welding.

[0045] like Figure 3 and Figure 4 As shown, the housing 10 is a rectangular block with a long side 13 and a short side 14. An opening 11 is located on the short side 14, and the end face 12 and the overlapping surface 311 are welded together at the short side 14. Because the welding perimeter of the short side of the rectangular block is shorter than the welding perimeter of the long side, the welding heat and welding time of the end face 12 and the overlapping surface 311 at the short side 14 are both shorter, which can effectively reduce the generated welding heat and reduce the possibility of heat being transferred to the battery cell.

[0046] like Figure 3 and Figure 4 As shown, the housing 10 includes multiple plates 15, which are sequentially bent to form a closed cylindrical structure. An opening 11 is located at at least one end of the cylindrical structure, and an end face 12 is formed on the end of the cylindrical structure located at the opening 11. This eliminates the need for steps as described in related technologies on the end face; a flat surface is sufficient, facilitating processing and reducing battery manufacturing costs. Preferably, there are four plates 15, which are sequentially bent to form a closed cylindrical structure.

[0047] The shell material of this application can be aluminum; aluminum alloy; specifically, it can be aluminum-manganese alloy, aluminum-magnesium alloy, etc. It can also be steel, specifically stainless steel; carbon steel; nickel-plated steel, etc. The cover plate material can be the same as the shell material.

[0048] Of course, in other embodiments, the housing 10 has openings at both ends. In this case, there are also two cover plates 30, one of which is a positive cover plate and the other is a negative cover plate. The positive cover plate and the negative cover plate are respectively assembled with the two openings.

[0049] In one embodiment, the battery can be a prism-shaped battery. A prism-shaped battery mainly refers to a battery with a prism shape, but it is not strictly limited that each side of the prism must be a straight line in the strict sense, and the corners between the sides do not have to be right angles, but can be rounded.

[0050] This application also provides an electrical device, an embodiment of which includes a battery, specifically the battery described above. Since the aforementioned battery can solve the problem of thermal runaway in related technologies, the electrical device including this battery cell can solve the same technical problem. The electrical device includes an electrical mechanism, which can be selected as a vehicle, ship, spacecraft, or similar mechanism. The electrical mechanism can supply power to vehicles, ships, and spacecraft.

[0051] The power-consuming device can be powered by a battery pack or battery module. The battery pack or battery module includes the batteries mentioned above.

[0052] The following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.

[0053] [Battery]

[0054] The battery in this application is a secondary battery, also known as a rechargeable battery or storage battery, which refers to a battery that can be used again after being discharged by recharging to activate the active materials.

[0055] Typically, a secondary battery consists of a battery cell, an electrolyte, and a casing. The battery cell includes a positive electrode, a negative electrode, and a separator. The battery cell and electrolyte are assembled inside the casing. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and releasing. The separator, located between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, situated between the positive and negative electrodes, mainly serves to conduct active ions.

[0056] As an example, the preparation process of a secondary battery is as follows: the positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrodes are wound or stacked to obtain a cell. The cell is placed in a casing, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a secondary battery is obtained.

[0057] [Positive electrode tablets]

[0058] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one side of the positive current collector. The positive electrode film layer includes a positive electrode active material, which can be any existing publicly disclosed positive electrode active material or a positive electrode active material optimized based on existing materials.

[0059] This application does not impose any particular restrictions on the type of positive electrode active material for the positive electrode sheet. As an example, the positive electrode active materials in this application include lithium-containing transition metal oxides (e.g., LiCoO2), phosphides (e.g., LiFePO4), or lithium intercalation compounds (e.g., positive electrode materials for binary lithium batteries such as lithium cobalt oxide and lithium nickel oxide, or positive electrode materials for ternary lithium batteries such as lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide).

[0060] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, rolling, cutting and other processes.

[0061] In this application, the binder is used to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. This application does not impose any particular limitation on the type of binder for the positive electrode sheet; the binder can be any conventional choice in the battery industry. Specifically, the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), polyacrylonitrile (PAN), polyimide (PI), polyacrylic acid (PAA), polyacrylate, polyolefin, sodium carboxymethyl cellulose (CMC), or sodium alginate.

[0062] This application does not impose any particular restrictions on the positive electrode current collector, as long as it is conductive and will not cause adverse chemical changes in the battery, and can be made of, for example: stainless steel, aluminum, nickel, titanium, sintered carbon; or aluminum or stainless steel that has been surface treated with one of carbon, nickel, titanium, silver, etc.

[0063] [Negative electrode plate]

[0064] The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. The negative electrode active material layer comprises a silicon-based material. This application does not specifically limit the type of silicon-based material; the silicon-based material can be a silicon-carbon material and / or a silicon-oxygen material. As an example, the silicon-based material can be one or more of silicon-carbon composite negative electrode materials, silicon suboxide negative electrode materials, modified silicon suboxide negative electrode materials, and nano-silicon materials. The negative electrode active material in the negative electrode active material layer may also optionally include one or more of artificial graphite, natural graphite, and hard carbon.

[0065] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, rolling, cutting and other processes.

[0066] This application does not specifically limit the type of negative electrode conductive agent. In some embodiments, as an example, the negative electrode conductive agent can be one or more of conventional negative electrode conductive agents such as acetylene black and carbon nanotubes. This application does not specifically limit the type of negative electrode binder. In some embodiments, as an example, the binder can be one or more of conventional negative electrode binders such as styrene-butadiene rubber latex (SBR), polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and sodium carboxymethyl cellulose (CMC). In this application, the binder is preferably PAA, SBR, and CMC, and the mass ratio of PAA, SBR, and CMC can be (34.38-74.29):(20-59.38):(5-7.14).

[0067] This application does not impose specific limitations on the type of negative electrode current collector. In some embodiments, as an example, the negative electrode current collector can be one of the conventional negative electrode current collectors such as copper foil.

[0068] Electrolyte

[0069] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. As an example, the electrolyte in this application can be any electrolyte suitable for electrochemical energy storage devices in the art. The electrolyte includes an electrolyte and a solvent; the electrolyte typically includes a lithium salt, and additives may also be added to the electrolyte.

[0070] Specifically, the lithium salt includes at least one selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP). The concentration of the electrolyte in the electrolyte solution can be 0.5–5 mol / L.

[0071] Specifically, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0072] In some implementations, as an example, the additive may be a conventional electrolyte additive such as fluoroethylene carbonate (FEC), chloroethylene carbonate (CEC), or vinylene carbonate (VC).

[0073] [Septum]

[0074] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0075] In some embodiments, as an example, the diaphragm can be one of PP, PE, or PP / PF; the diaphragm can also be a structure in which a coating is formed on the surface of the base film, wherein the base film coating can be one of PP, PE, or PP / PF, and the coating can be an inorganic coating and / or an organic coating. The inorganic coating can be selected from alumina ceramic layers, osmium silicate, etc., and the organic coating can be selected from PVDF, etc.

[0076] In the description of this utility model, it should be understood that "multiple" means a quantity of two or more. Directional terms such as "front, back, up, down, left, right," "horizontal, vertical, perpendicular, horizontal," and "top, bottom" indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are used solely for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner or outer contours relative to the outline of each component itself.

[0077] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0078] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0079] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A battery, characterized in that, include: A housing (10), wherein at least one end of the housing (10) is provided with an opening (11); The battery cell (20) is disposed inside the housing (10); A cover plate (30) is provided over the opening (11). The cover plate includes a cover plate body (32) and a stepped portion (31) disposed on the outer periphery of the cover plate body (32). The housing (10) has an end face (12) located at the opening (11). The stepped portion (31) has an overlapping surface (311) that overlaps the end face (12). The overlapping surface (311) and the end face (12) form a... The overlapping area (16) is formed, the end face (12) is connected to the overlapping surface (311), the end face (12) is a plane, the width of the overlapping area (16) in the direction (X) parallel to the end face (12) is a mm, and the distance between the overlapping surface (311) in the direction (Y) perpendicular to the end face (12) and the negative electrode plate (22) of the cell (20) is b mm, where a × b satisfies: 1.2 mm 2 ≦(a×b)≦15mm 2 .

2. The battery according to claim 1, characterized in that, The end face (12) is welded to the overlapping surface (311) to form a welding area (17) between the end face (12) and the overlapping surface (311). The welding area (17) and the inner edge of the shell (10) are spaced apart, and b satisfies: 3.5mm≦b≦13mm.

3. The battery according to claim 2, characterized in that, The welding area (17) extends to the inner edge of the housing (10), and b satisfies: 4mm≦b≦15mm.

4. The battery according to claim 2, characterized in that, The ratio of the width of the welding area (17) to the width of the end face (12) is greater than or equal to 0.8 and less than or equal to 2.

5. The battery according to claim 1, characterized in that, The battery cell (20) includes a negative electrode (22) and a positive electrode (23). In the direction (Y) perpendicular to the end face (12), the negative electrode (22) protrudes from the positive electrode (23), and b satisfies: 3.5mm≦b≦16mm.

6. The battery according to claim 1, characterized in that, The cell (20) includes a positive electrode (23), and in the direction (Y) perpendicular to the end face (12), the distance (H1) between the overlapping surface (311) and the positive electrode (23) is greater than or equal to 4.7 mm and less than or equal to 18 mm.

7. The battery according to claim 1, characterized in that, The stepped portion (31) includes an overlapping portion (312) that overlaps the end face (12) and an insertion portion (313) connected to the overlapping portion (312). At least a portion of the insertion portion (313) is embedded in the housing (10). The ratio between the dimension of the insertion portion (313) in the direction (Y) perpendicular to the end face (12) and the thickness of the cover plate (30) is greater than or equal to 0.45 and less than or equal to 0.

85.

8. The battery according to claim 1, characterized in that, The ratio between a and the wall thickness of the shell (10) is greater than or equal to 0.5 and less than or equal to 1; and / or, a is greater than or equal to 0.3 mm and less than or equal to 1.2 mm.

9. The battery according to claim 1, characterized in that, The distance (H2) between the inner wall of the housing (10) and the battery cell (20) is greater than or equal to 2 mm and less than or equal to 3.5 mm.

10. The battery according to claim 1, characterized in that, The housing (10) is a rectangular block with a long side (13) and a short side (14). The opening (11) is located on the short side (14), and the end face (12) and the overlapping surface (311) are welded together at the short side (14).

11. The battery according to claim 1, characterized in that, The housing (10) includes a plurality of plates (15), which are bent in sequence to form a cylindrical structure that is closed at both ends. The opening (11) is located at at least one end of the cylindrical structure, and the end face (12) is formed on one end of the cylindrical structure located at the opening (11).

12. An electrical device comprising a battery, characterized in that, The battery is the battery according to any one of claims 1 to 11.

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