Battery shell, battery and electric device

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a battery shell which comprises a shell body and a cover plate covering the shell body, a containing cavity is defined by the shell body and the cover plate, the containing cavity is used for placing a battery cell, a reinforcing protection layer is arranged on one face, away from the containing cavity, of the cover plate, and the reinforcing protection layer is used for protecting the battery cell. The reinforcing protection layer is of a hollow structure protruding relative to the plane of the cover plate and comprises a plurality of reinforcing units connected with one another. By arranging the reinforced protective layer, the plastic strain capacity of the cover plate can be improved, so that the influence on the application of the battery caused by large deformation when the battery is impacted or falls off in the transportation or use process is avoided, and the safety performance of the battery is further improved; in addition, the reinforcing protection layer is of a groove structure protruding outwards relative to the containing cavity, electrolyte can be stored, and then the electrolyte retention capacity of the battery is improved. In addition, the utility model also discloses a battery comprising the battery shell and an electric device.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and specifically relates to a battery shell, a battery and an electrical device. Background Art

[0002] Nowadays, with the development of modern society and the enhancement of people's environmental awareness, more and more devices choose lithium-ion batteries as power sources, such as mobile phones, laptops, power tools and electric vehicles, which provides a broad space for the application and development of lithium-ion batteries.

[0003] At present, in order to adapt to the continuous improvement of battery energy density, the shell and cover thickness of the mainstream application of square steel shell batteries are relatively thin. The cover thickness has been reduced to 75μm, and it is still developing in the direction of thinner. The reduced thickness of the cover will cause residual compressive plastic strain to be generated when the battery is heated or plastically stretched under external force due to the difference between the amount of plastic extrusion and the amount of plastic stretching, which will cause large-surface concave-convex deformation of the battery, especially for battery shells with larger size and thinner wall thickness, the deformation of the cover is more obvious. Therefore, it is urgent to propose a new technical solution to solve the above problems. Utility Model Content

[0004] One of the purposes of the utility model is to provide a battery housing in view of the deficiencies of the prior art, which improves the plastic strain capacity of the cover plate by arranging a reinforced protective layer on the surface of the cover plate, thereby improving the safety performance of the battery.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A battery casing comprises a shell and a cover plate arranged on the shell, wherein the shell and the cover plate enclose a receiving cavity, wherein the receiving cavity is used to place a battery cell, and a reinforcing protective layer is arranged on a side of the cover plate away from the receiving cavity, wherein the reinforcing protective layer is a hollow structure protruding relative to the plane of the cover plate, and wherein the reinforcing protective layer comprises a plurality of mutually connected reinforcing units.

[0007] As an improvement of the battery housing of the utility model, the protrusion height of the reinforced protective layer relative to the plane of the cover plate is 2 μm-6 μm.

[0008] As an improvement of the battery casing described in the utility model, when the reinforcing unit is set to a circular structure, the diameter of the reinforcing unit is 1mm-3.6mm, the reinforcing units are evenly distributed on the surface of the cover plate, and the density of the reinforcing units is 4-12 per square centimeter.

[0009] As an improvement of the battery casing described in the utility model, the reinforcing unit is a regular polygonal structure, the side length of the reinforcing unit is 3mm-6mm, the protrusion width D of the reinforcing unit and its side length L satisfy the relationship: 0.25L≤D<L, the reinforcing units are evenly distributed on the surface of the cover plate, and the density of the reinforcing units is 1-4 per square centimeter.

[0010] The second object of the present utility model is to provide a battery, comprising the battery casing and a battery cell as described above, wherein the battery cell is accommodated in a receiving cavity of the battery casing.

[0011] The third object of the present utility model is to provide an electrical device comprising the battery as described above.

[0012] The beneficial effect of the utility model is that the battery housing of the utility model includes a shell and a cover plate covering the shell, the shell and the cover plate enclose a receiving cavity, the receiving cavity is used to place the battery cell, and is characterized in that a reinforcing protective layer is provided on a side of the cover plate away from the receiving cavity, the reinforcing protective layer is a hollow structure protruding relative to the plane of the cover plate, and the reinforcing protective layer includes a plurality of mutually connected reinforcing units. The utility model can improve the plastic strain capacity of the cover plate by providing a reinforcing protective layer, thereby preventing the battery from being greatly deformed when it is hit or dropped during transportation or use, thereby improving the safety performance of the battery; in addition, the reinforcing protective layer is a groove structure protruding outward relative to the receiving cavity, which can store electrolyte, thereby improving the liquid retention of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0014] Figure 1 It is a schematic diagram of the structure of the battery in the utility model.

[0015] Figure 2 It is a structural schematic diagram of the reinforced protective layer in the utility model.

[0016] The reference numerals are described as follows:

[0017] 1- housing;

[0018] 2-cover plate;

[0019] 3-accommodating cavity;

[0020] 4- Protective layer;

[0021] 200-battery cells. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0024] Reference to "embodiment" in this application means that a particular feature, structure or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0025] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0026] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0027] The term "plurality" used in the present application refers to two or more (including two).

[0028] The battery cell includes a battery core and an electrolyte. The battery core is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer. The negative electrode collector not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that a large current can pass without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the battery cell may be a wound structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0029] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0030] The inventors found that steel-shell batteries have higher energy density due to their thinner shell material and smaller packaging position. In addition, steel-shell batteries have better packaging reliability and cell size consistency, which greatly improves battery safety. This type of battery has become one of the main energy storage devices for mainstream electronic products. In order to adapt to the continuous improvement of battery energy density, the shell and cover thickness of mainstream square steel-shell batteries are now thinner, among which the cover thickness has been reduced to 75μm, and is still developing in a thinner direction. The thickness of the cover is reduced. When the battery is heated or plastically stretched under the action of external force, the difference between the amount of plastic extrusion and the amount of plastic stretching will produce residual compressive plastic strain, the size and distribution of which determine the final residual stress and deformation, which in turn causes large-surface concave-convex deformation of the battery, especially for battery shells with larger sizes and thinner walls, the deformation of the cover is more obvious.

[0031] In view of this, the embodiment of the present application provides a technical solution, which can increase the plastic strain capacity of the steel shell battery casing by setting a reinforced protective layer on the cover plate, thereby preventing the cover plate from deforming.

[0032] The following is combined with Figures 1-2The utility model is further described in detail with specific implementation modes, but is not intended to limit the utility model.

[0033] A battery casing comprises a shell 1 and a cover plate 2 covering the shell 1, the shell 1 and the cover plate 2 enclose a receiving cavity 3, the receiving cavity 3 is used to place a battery cell 200, a reinforced protective layer 4 is provided on a side of the cover plate 2 away from the receiving cavity 3, the reinforced protective layer 4 is a hollow structure protruding relative to the plane of the cover plate 2, and the reinforced protective layer 4 includes a plurality of mutually connected reinforcing units.

[0034] In the utility model, the battery shell is a shell used for steel shell batteries, wherein the thickness of the cover plate 2 is less than or equal to 75 mm, and a reinforced protective layer 4 is arranged on the outer surface of the cover plate 2, which can enhance the plastic strain capacity of the cover plate 2, and prevent the battery using the above-mentioned battery shell from being deformed by impact or falling during transportation or use, thereby affecting the battery performance; at the same time, since the reinforced protective layer 4 is a raised hollow structure, it is a groove structure relative to the accommodating cavity 3, and compared with the existing planar structure, it can store more electrolyte, further improving the battery's liquid retention capacity.

[0035] It is understandable that in some embodiments, in order to further enhance the plastic strain capacity of the battery housing, one or more outer surfaces of the shell 1 may also be provided with a reinforced protective layer 4, which can be adjusted according to actual conditions without specific regulations.

[0036] Preferably, the protrusion height of the reinforced protective layer 4 relative to the plane of the cover plate 2 is 2μm-6μm. In the present embodiment, the reinforcing unit is a regular hexagonal structure, the side length of the reinforcing unit is 3mm-6mm, the protrusion width D of the reinforcing unit and its side length L satisfy the relationship: 0.25L≤D<L, the reinforcing units are evenly distributed on the surface of the cover plate 2, and the density of the reinforcing units is 1-4 per square centimeter. The setting of the above-mentioned reinforcing unit parameters does not affect the volume energy density of the battery, and can make the formation pressure evenly distributed on the surface of the cover plate 2, thereby avoiding excessive pressure on the local part of the battery shell. In addition, the gas generated during the formation process can be eliminated from the inside of the battery, thereby avoiding the situation where the battery thickness and performance are affected by residual gas, and applying uniform pressure can also help eliminate the suction phenomenon on the anode sheet in the battery and improve the cycle performance.

[0037] It is understandable that in some other embodiments, the structure of the reinforcing unit may also be set to other regular polygonal structures, and the side length of the reinforcing unit is adjusted according to the density of the reinforcing unit and actual needs.

[0038] In some other embodiments, the reinforcing unit is set to a circular structure, the diameter of the reinforcing unit is 1mm-3.6mm, the reinforcing unit is evenly distributed on the surface of the cover plate 2, and the density of the reinforcing unit is 4-12 per square centimeter, further avoiding the situation where the setting of the reinforcing unit affects the volume energy density of the battery.

[0039] Battery

[0040] A battery comprises the battery casing and a battery cell 200 as described above, wherein the battery cell 200 is accommodated in a receiving cavity 3 of the battery casing.

[0041] In order to better illustrate the beneficial effects of this embodiment, the following examples and comparative examples are provided for illustration.

[0042] Example 1

[0043] The preparation of a battery including the above-mentioned battery shell includes the following steps: preparing a positive electrode sheet, fully dispersing the active material LiCoO2, the conductive agent acetylene black, the conductive carbon nanotubes, and the binder polyvinylidene fluoride (PVDF) in an N-methylpyrrolidone solvent system at a weight ratio of 97.6:0.5:0.6:1.3, and evenly coating them on the positive electrode collector, and then cold pressing and slitting to obtain the positive electrode sheet; preparing a negative electrode sheet, mixing the negative electrode active material, the conductive agent (SP and CNT mixed in a mass ratio of 0.45:0.05), and the binder (SBR and PAALi mixed in a mass ratio of 0.5:1.8) in a weight ratio of 97.7:1.1:1.2, preparing a negative electrode active material slurry and evenly coating it on the negative electrode collector, and then cold pressing and slitting to obtain To the anode electrode; make a separator: coat the PE surface with a ceramic mixture as a separator; make an electrolyte: mix ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and propyl propionate (PP) in a volume ratio of 1.2:1:4:4, and then dissolve the fully dried lithium salt LiPF6 in a mixed organic solvent at a ratio of 1 mol / L to prepare an electrolyte; wind or stack the above-mentioned positive electrode, separator, and negative electrode to produce a bare battery cell, and then put it into a battery shell for packaging, and inject the electrolyte to produce a finished lithium-ion battery; in the production of the battery shell, the reinforcing unit of the cover plate 1 is set to a circular structure, with a distribution number of 4 per square centimeter, the diameter of the reinforcing unit is set to 3 mm, and the protrusion height is 3 μm.

[0044] Example 2

[0045] The difference between this embodiment and embodiment 1 is that in this embodiment, the reinforcing unit of the cover plate 1 is set as a square structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 1 mm, and the protrusion height is 3 μm.

[0046] Example 3

[0047] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 1 mm, and the protrusion height is 3 μm.

[0048] Example 4

[0049] The difference between this embodiment and embodiment 1 is that in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 6 units distributed per square centimeter, the side length L of the reinforcing unit is set to 6 mm, the protrusion width is set to 2 mm, and the protrusion height is 3 μm.

[0050] Example 5

[0051] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 0.75 mm, and the protrusion height is 3 μm.

[0052] Example 6

[0053] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 1.5 mm, and the protrusion height is 3 μm.

[0054] Example 7

[0055] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 1 mm, and the protrusion height is 2 μm.

[0056] Example 8

[0057] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 1 mm, and the protrusion height is 6 μm.

[0058] Example 9

[0059] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 1 mm, and the protrusion height is 8 μm.

[0060] Example 10

[0061] The difference between this embodiment and embodiment 1 is that: in this embodiment, the reinforcing unit of the cover plate 1 is set as a regular hexagonal structure, with 4 units distributed per square centimeter, the side length L of the reinforcing unit is set to 3 mm, the protrusion width is set to 3 mm, and the protrusion height is 3 μm.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 1 is that the quilt 1 of this comparative example is not provided with a reinforced protective layer 4 .

[0064] The liquid retention amount of the above-mentioned embodiments and comparative examples was calculated, and the liquid retention amount calculation formula was: liquid retention amount (g) = liquid injection amount (g) - mass of extracted electrolyte (g), wherein the liquid injection amount was 8.2g; and a battery drop test was performed on the above-mentioned embodiments and comparative examples to observe whether their shells were deformed. The battery drop test method was: a packaging box containing the batteries of the above-mentioned embodiments and comparative examples was freely dropped from a height of 1.2 meters along three different axial surfaces and diagonal directions onto a cement floor.

[0065] Cycle test method: In 25℃ or 45℃ environment, cycle test is carried out according to the following method, charging mode: 3C CC to 4.25V, 2.5C CC to 4.35V, CV to 1.8C, 1.8C CC to 4.4V, CV to 1.5C, 1.5C CC to4.5V, CV to 1.2C, 1.2C CC to 4.55V, CV to 0.26C; discharge mode: 0.7C DC to 3.0V. 500-week capacity retention rate = discharge capacity of the 500th week / discharge capacity of the 1st week * 100%; 500-week expansion rate = (thickness of the 500th week - initial half-electric thickness) / initial half-electric thickness * 100%; initial half-electric thickness: charge at a constant current of 0.5C to 3.96V and constant voltage to 0.02C, all battery cell thicknesses are tested using 600PPG. The results are shown in Table 1.

[0066] Table 1

[0067]

[0068]

[0069] According to the contents of the above table, a reinforced protective layer 4 composed of reinforcing units with the above-mentioned parameter settings is arranged on the outer surface of the cover plate 1, which can increase the plastic strain capacity of the battery shell, avoid deformation of the battery shell, and improve the liquid retention of the battery; at the same time, it helps to make the stress distribution more uniform under external force compression during the battery formation stage, so that the long cycle performance of the battery is better.

[0070] Electrical devices

[0071] An electrical device, including a battery as described above. The electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft may include an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool may include a metal cutting electric tool, a grinding electric tool, an assembly electric tool and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0072] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A battery casing, comprising a shell (1) and a cover plate (2) covering the shell (1), wherein the shell (1) and the cover plate (2) enclose a receiving cavity (3), wherein the receiving cavity (3) is used to place a battery cell (200), and wherein: A reinforcing protective layer (4) is provided on a side of the cover plate (2) away from the accommodating cavity (3); the reinforcing protective layer (4) is a hollow structure protruding relative to the plane of the cover plate (2); and the reinforcing protective layer (4) comprises a plurality of mutually connected reinforcing units.

2. The battery housing according to claim 1, wherein: The protrusion height of the reinforced protective layer (4) relative to the plane of the cover plate (2) is 2 μm-6 μm.

3. The battery housing according to claim 1, characterized in that: The reinforcement unit is configured as a circular structure.

4. The battery housing according to claim 3, characterized in that The diameter of the reinforcement unit is 1 mm-3.6 mm.

5. The battery housing according to claim 3, characterized in that: The reinforcing units are evenly distributed on the surface of the cover plate (2), and the density of the reinforcing units is 4-12 per square centimeter.

6. The battery housing according to claim 1, wherein: The reinforcing unit is a regular polygonal structure, and the side length of the reinforcing unit is 3mm-6mm.

7. The battery housing according to claim 6, characterized in that: The protrusion width D of the reinforcing unit and its side length L satisfy the relationship: 0.25L≤D<L.

8. The battery housing according to claim 6, wherein: The reinforcing units are evenly distributed on the surface of the cover plate (2), and the density of the reinforcing units is 1-4 per square centimeter.

9. A battery, characterized in that: It comprises a battery casing and a battery cell (200) as claimed in any one of claims 1 to 8, wherein the battery cell (200) is accommodated in a receiving cavity (3) of the battery casing.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

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