Secondary battery, battery pack, and electronic device

Abstract

The embodiment of the utility model discloses a secondary battery, a battery pack and an electronic device. The secondary battery comprises an electrode assembly; the shell is used for limiting a containing cavity for containing the electrode assembly, and the shell is provided with an opening; and the cover plate assembly covers the opening of the shell so as to package the electrode assembly. The cover plate assembly comprises a cover plate base body; and an insulating layer on a surface of the cover plate substrate facing the electrode assembly. According to the technical scheme, at least the corrosion resistance of the cover plate assembly of the secondary battery can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage equipment, and more specifically, to a secondary battery, a battery pack and an electronic device. Background Art

[0002] In the field of new energy power batteries, the application of secondary batteries is becoming increasingly widespread. For example, secondary batteries (such as lithium-ion batteries) can be applied to electronic devices such as cars, energy storage, mobile phones, tablets, wearable devices, mobile power supplies, electronic cigarettes, digital products, power tools, power devices, energy storage devices, etc. One type of secondary battery is a cylindrical battery. The cylindrical battery includes a housing and an electrode assembly. The electrode assembly includes a positive electrode sheet, a first separator, a negative electrode sheet, and a second separator. The electrodes are stacked in sequence and wound into an electrode assembly, which is then encapsulated in a housing. However, existing secondary batteries still need further improvement in some aspects. Utility Model Content

[0003] In view of the problems existing in the related art, the purpose of the present invention is to provide a secondary battery, a battery pack and an electronic device, so as to at least improve the corrosion resistance of the cover assembly of the secondary battery.

[0004] To achieve the above objectives, embodiments of the present application provide a secondary battery comprising: an electrode assembly; a housing defining a cavity for accommodating the electrode assembly, the housing having an opening; and a cover assembly that covers the opening of the housing to encapsulate the electrode assembly. The cover assembly comprises a cover base; and an insulating layer disposed on a surface of the cover base that faces the electrode assembly.

[0005] In the above technical solution, an insulating layer is provided on the surface of the cover plate substrate of the cover plate assembly facing the electrode assembly to isolate the electrolyte from the cover plate substrate, thereby slowing down or avoiding corrosion of the cover plate substrate by the electrolyte, thereby improving the corrosion resistance of the cover plate assembly.

[0006] In some embodiments, the surface of the cap plate substrate facing the electrode assembly has a notch, wherein the insulating layer covers the notch.

[0007] In some embodiments, a metal layer is disposed between the cover substrate and the insulating layer.

[0008] In some embodiments, a distance between an edge of the insulating layer and an edge of the cover substrate is greater than or equal to 0.5 mm and less than or equal to 5 mm.

[0009] In some embodiments, the insulating layer covers the entire surface of the cap plate base facing the electrode assembly.

[0010] In some embodiments, the insulating layer is a UV-curable adhesive layer.

[0011] In some embodiments, a crimping portion protruding inward is provided on the side wall of the shell adjacent to the opening, and the crimping portion includes a straight portion arranged parallel to the surface of the cover base, wherein the edge of the insulating layer is located between the straight portion and the cover base, and the secondary battery is a cylindrical battery.

[0012] In some embodiments, the cover plate base is circular, and the area where the straight portion overlaps with the projection of the cover plate base in a direction perpendicular to the surface is a sealing area, wherein the portion of the insulating layer located in the sealing area has a width in the diameter direction of the cover plate base, and the width ranges from 0.5 mm to 3 mm.

[0013] An embodiment of the present application further provides a battery pack, which includes any one of the above-mentioned secondary batteries.

[0014] An embodiment of the present application further provides an electronic device, which includes the above-mentioned battery pack.

[0015] The beneficial technical effects of the present utility model are:

[0016] By providing an insulating layer on the surface of the cover plate substrate of the cover plate assembly facing the electrode assembly, the electrolyte is isolated from the cover plate substrate, which can slow down or avoid the corrosion of the cover plate substrate by the electrolyte, thereby improving the corrosion resistance of the cover plate assembly. In addition, the notches of the cover plate substrate are more susceptible to corrosion by the electrolyte. The present application uses an insulating layer to cover the notches, which can effectively protect the notches from corrosion by the electrolyte. In addition, by providing a metal layer between the cover plate substrate and the insulating layer, the cover plate substrate can be further protected from rust / corrosion. In addition, by providing the edge of the insulating layer in the sealing area formed by the crimping portion, it can be ensured that the electrolyte will not enter between the insulating layer and the cover plate substrate through the edge of the insulating layer, thereby isolating the electrolyte well and effectively preventing the cover plate substrate from being corroded by the electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A schematic diagram showing an electronic device according to an embodiment of the present application is a vehicle.

[0019] Figure 2 A perspective view of a secondary battery according to an embodiment of the present application is shown.

[0020] Figure 3A cross-sectional view of a secondary battery according to an embodiment of the present application is shown.

[0021] Figure 4 According to one embodiment of the present application Figure 3 A schematic cross-sectional view of a cover assembly of a secondary battery.

[0022] Figure 5 4 is a schematic cross-sectional view of a cap assembly of a secondary battery according to an embodiment of the present application.

[0023] Figure 6 According to the embodiment of this application Figure 3 A partially enlarged cross-sectional schematic diagram of the cover assembly of the secondary battery. DETAILED DESCRIPTION

[0024] In order to better understand the spirit of the embodiments of the present application, some preferred embodiments of the present application are further described below.

[0025] The embodiments of the present application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are represented by similar reference numerals. The embodiments described herein with respect to the accompanying drawings are illustrative and diagrammatic and are intended to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0026] As used herein, the terms "substantially," "substantially," "essentially," and "about" are used to describe and illustrate small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred precisely as well as instances where the event or circumstance occurred very approximately.

[0027] In this specification, unless otherwise specified or limited, relative terms such as "central", "longitudinal", "lateral", "front", "rear", "right", "left", "inner", "outer", "lower", "higher", "horizontal", "vertical", "above", "below", "above", "below", "top", "bottom" and their derivatives (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are only used for convenience of description and do not require that the present application be constructed or operated in a specific orientation.

[0028] For ease of description, “first,” “second,” “third,” etc. may be used herein to distinguish different components in a figure or a series of figures. “First,” “second,” “third,” etc. are not intended to describe the corresponding components.

[0029] See also Figure 1 For ease of explanation, the following embodiments are described using a vehicle 1000 as an electronic device. However, it is readily understood that the electronic device provided herein is not limited to vehicles. The electronic device may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, electric tools, and the like.

[0030] The interior of the vehicle 1000 may be provided with a battery pack 1002, which may be provided at the bottom of the vehicle body 1001 (e.g., Figure 1 As shown), or head, or tail, or any other appropriate position. The battery pack 1002 can be used to power the vehicle 1000. For example, the battery pack 1002 can be used as an operating power source or a driving power source for the vehicle 1000. The battery pack 1002 may include a plurality of secondary batteries (such as Figure 2 The secondary battery 100 is a battery in a plurality of ways and a housing for accommodating the plurality of secondary batteries.

[0031] Figure 2 A perspective view of a secondary battery 100 according to an embodiment of the present application is shown. Figure 3 1 shows a cross-sectional view of a secondary battery 100 according to an embodiment of the present application. In this embodiment, the secondary battery 100 is shown as a cylindrical battery as an example. Figure 2 and Figure 3 , the secondary battery 100 may include an electrode assembly 120, a shell 200 and a cover assembly 220. The shell 200 and the cover assembly 220 are components that jointly accommodate the electrode assembly 120 and the electrolyte. The material of the shell 200 can be any of a variety of available materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The shell 200 can be cylindrical and define a receiving cavity, and the electrode assembly 120 is disposed in the receiving cavity. The diameter of the shell 200 can be determined according to the specific diameter size of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc. In some embodiments, the secondary battery 100 can be a 4680 cylindrical battery (diameter 46mm, height 80mm), or the secondary battery 100 can be a 4695 cylindrical battery (diameter 46mm, height 95mm), or the secondary battery 100 can be a 46120 cylindrical battery (diameter 46mm, height 120mm).

[0032] The electrode assembly 120 may include a first electrode sheet, a first separator, a second electrode sheet, and a second separator, which are stacked and wound in sequence. The electrolyte may be located between the first electrode sheet, the first separator, the second electrode sheet, and the separator. In some embodiments, the first electrode sheet is one of a positive electrode sheet and a negative electrode sheet, and the second electrode sheet is the other of the positive electrode sheet and the negative electrode sheet.

[0033] The positive electrode plate may include a positive electrode current collector and a positive electrode active material layer coated on both sides of the positive electrode current collector. The portion of the positive electrode current collector not coated with the positive electrode active material layer constitutes the positive electrode tab. The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer coated on both sides of the negative electrode current collector. The portion of the negative electrode current collector not coated with the negative electrode active material layer constitutes the negative electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material layer may include a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The material of the negative electrode current collector may be copper, and the negative electrode active material layer may include a negative electrode active material, which may be carbon or silicon, etc. In some embodiments, the material of the first diaphragm and the second diaphragm may be, for example, PP (polypropylene) or PE (polyethylene).

[0034] By coating a positive electrode active material layer on the positive electrode sheet, the positive electrode active material layer contains lithium ions. When the positive electrode active material layer is in contact with the electrolyte and the battery is charged, the lithium ions in the positive electrode active material layer will move through the electrolyte to the negative electrode active material layer and be embedded in the negative electrode active material layer. This process is the process of lithium ion activation and is also the process of battery charging.

[0035] The housing 200 may have an opening 205 at one end along the height direction (direction Z) and an end wall 111 at the other end. The electrode assembly 120 may be provided with a positive electrode tab facing the end wall 111 and a negative electrode tab facing the opening 205 at both ends along the direction Z, respectively. In some embodiments, the electrode post 10 may be connected to the positive electrode tab of the electrode assembly 120 via the positive electrode current collecting plate 50, thereby making the electrode post 10 positively charged and enabling the electrode post 10 to function as a positive terminal in the secondary battery 100. The negative electrode tab of the electrode assembly 120 may be connected to the housing 200 via the negative electrode current collecting plate 70, thereby making the housing 200 negatively charged. The electrode post 10 may be electrically insulated from the negatively charged housing 200. Electrical insulation between the electrode post 10 and the housing 200 can be achieved in various ways. For example, an upper plastic 20 and a lower plastic 40 may be sandwiched between the electrode post 10 and the housing 200 to achieve an electrically insulated state between the electrode post 10 and the housing 200.

[0036] The cover plate assembly 220 covers the opening 205 of the housing 200 and seals the housing cavity of the housing 200, thereby encapsulating the electrode assembly 120 and the electrolyte. Since the housing 200 and the cover plate assembly 220 are used to contain the electrolyte, which is an acidic solution with strong corrosiveness, the cover plate assembly 220 is easily corroded by the electrolyte during battery use.

[0037] Figure 4 According to one embodiment of the present application Figure 3 Schematic cross-sectional view of the cap assembly 220 of the secondary battery 100. Figure 4 and combined Figure 3 As shown, the cap plate assembly 220 may include a cap plate base 90 and an insulating layer 93. The cap plate base 90 has a surface 90s facing the electrode assembly 120. The insulating layer 93 may be located on the surface 90s of the cap plate base 90 facing the electrode assembly 120 and the electrolyte. The insulating layer 93 may be used to isolate the electrolyte from the cap plate base 90.

[0038] By providing an insulating layer 93 on the surface 90s of the cover plate substrate 90 facing the electrode assembly 120, the electrolyte can be isolated from the cover plate substrate 90, which can slow down or avoid corrosion of the cover plate substrate 90 caused by the electrolyte, thereby improving the corrosion resistance of the cover plate assembly 220.

[0039] refer to Figure 4 As shown, the surface 90s of the cover plate substrate 90 facing the electrode assembly may have a notch 92, and the notch 92 may be concave relative to the surface 90s of the cover plate substrate 90. By forming the notch 92, a weak portion 98 may be formed. The thickness of the weak portion 98 is less than the thickness of other areas of the cover plate substrate 90. The concave notch 92 may be formed by removing a portion of the cover plate substrate 90. In some embodiments, the weak portion 98 may be annular in the top view of the cover plate substrate 90. Compared with other areas of the cover plate substrate 90, the weak portion 98 is weaker and more likely to break. When thermal runaway occurs in the battery, the high-temperature and high-pressure emissions inside the battery can break through the weak portion 98 on the cover plate assembly 220 and be discharged to the outside, thereby achieving good discharge of the emissions.

[0040] According to an embodiment of the present application, an insulating layer 93 covers the notch 92. Typically, the notch 92 of the cover substrate 90 is more susceptible to corrosion by the electrolyte. By covering the notch 92 with the insulating layer 93, the present application can effectively protect the notch 92 from corrosion by the electrolyte.

[0041] In some embodiments, a metal layer (not shown) may be provided between the cover substrate 90 and the insulating layer 93. The metal layer may be provided on the entire surface of the cover substrate 90. By providing the metal layer, the cover substrate 90 can be further protected from rust / corrosion. The material of the metal layer may be a material having higher corrosion resistance to the electrolyte than the material of the gold cover substrate 90. In one example, the cover substrate 90 may be made of a metal (e.g., a metal containing Fe (iron) elements), for example, the material of the cover substrate 90 may be steel (e.g., low carbon steel). The metal layer may be, for example, a Ni (nickel) layer, specifically, a nickel-plated layer electroplated on the surface of the cover substrate 90. Because the Ni element has good stability and high corrosion resistance in the electrolyte, it can generally further protect the cover substrate 90.

[0042] In addition, for a cover substrate 90 pre-plated with a metal layer (e.g., a Ni layer), since the formation of a notch 92 on the surface 90s will damage the metal layer at the notch 92, the cover substrate 90 may not be completely covered by the metal layer, and the proportion of exposed cover substrate 90 (e.g., Fe element) increases. The exposed cover substrate 90 will be preferentially corroded by the electrolyte, making the cover substrate 90 more susceptible to rust / corrosion. According to an embodiment of the present application, by covering the notch 92 with an insulating layer 93, the cover substrate 90 (e.g., Fe element) exposed after the notch 92 is formed can be isolated from the electrolyte, which can effectively prevent the exposed cover substrate 90 from rusting / corroding.

[0043] Continue to refer Figure 4 As shown, in some embodiments, the insulating layer 93 may cover a portion of the surface 90s of the cover plate substrate 90. The insulating layer 93 may cover the middle area of ​​the cover plate substrate 90, while exposing the edge area of ​​the cover plate substrate 90. In an embodiment where the cover plate assembly 220 is for a cylindrical battery, the cover plate substrate 90 may have a circular top view shape, and the insulating layer 93 may also have a circular top view shape. In the diameter direction (direction X) of the cover plate substrate 90, there may be a non-zero distance a between the edge of the insulating layer 93 and the edge of the cover plate substrate 90. The distance a may correspond to the width of the edge area of ​​the cover plate substrate 90 that is not covered by the insulating layer 93. In some embodiments, the distance a may be greater than or equal to 0.5 mm and less than or equal to 5 mm (5 mm ≥ a ≥ 0.5 mm). By configuring the distance a to be 5mm≥a≥0.5mm, the area covered by the insulating layer 93 on the cover substrate 90 can be appropriately made large enough to ensure that the surface 90s of the cover substrate 90 in the area that may contact the electrolyte is covered by the insulating layer 93, which can effectively isolate the electrolyte and slow down or prevent the cover substrate 90 from being corroded by the electrolyte.

[0044] The insulating layer 93 can be made of any material suitable for isolating the electrolyte. In some embodiments, the insulating layer 93 can be a UV (ultraviolet light curing) adhesive layer. The UV adhesive layer can be formed by spraying UV adhesive onto the cover substrate 90 and then curing the UV adhesive using ultraviolet light. The main component of the UV adhesive layer can be an acrylate. UV adhesive has the advantages of fast curing and easy formation, and the cured UV adhesive layer can achieve good isolation effect.

[0045] In some embodiments, the thickness of the insulating layer 93 may range from 20 μm to 200 μm. If the thickness of the insulating layer 93 is less than 20 μm, it may not provide the desired isolation effect. If the thickness is greater than 200 μm, it may occupy too much space inside the battery. The insulating layer 93 having a thickness ranging from 20 μm to 200 μm may provide good electrolyte isolation without occupying too much space inside the battery. In an embodiment in which the insulating layer 93 is a UV adhesive layer, the thickness of the insulating layer 93 may range from 30 μm to 70 μm. Since the UV adhesive layer may provide a good electrolyte isolation effect, the thickness of the insulating layer 93 may be reduced to within a range of 30 μm to 70 μm, so as not to occupy too much space inside the battery.

[0046] Figure 5 FIG is a cross-sectional view of a cap assembly of a secondary battery 100 according to another embodiment of the present application. Figure 5 As shown, Figure 4 The difference of the illustrated embodiment is that the insulating layer 93 can cover the entire area of ​​the surface 90s. By configuring the insulating layer 93 to cover the entire surface 90s of the cap substrate 90 facing the electrode assembly 120, it can be ensured that the insulating layer 93 completely isolates the electrolyte from the cap substrate 90.

[0047] Figure 6 According to the embodiment of this application Figure 3 A partially enlarged cross-sectional view of the cap plate assembly 220 of the secondary battery 100. Figure 6 As shown, a press-fit portion 31 protruding inwardly may be provided on the side wall of the housing 200 adjacent to the opening 205. The press-fit portion 31 may be a rolling groove structure formed by bending a portion of the side wall of the housing 200 inwardly.

[0048] In addition, the end portion of the housing 200 on the side of the opening 205 can be configured as a curling portion 32, which extends inwardly along the radial direction (direction X) of the housing 200. The crimping portion 31 and the curling portion 32 are spaced apart along the direction Z, and the crimping portion 31 and the curling portion 32 can jointly clamp the cover plate assembly 220. The cover plate assembly 220 and the housing 200 can be further sealed by a sealing ring 80. Along the direction Z, the electrode assembly 120 is disposed on the end wall 111 (see FIG. Figure 3 ) and the crimping portion 31. The crimping portion 31 can limit the movement of the electrode assembly 120 along the Z direction between the end wall 111 of the housing 200 and the crimping portion 31. The crimping portion 31 can jointly provide support and positioning for the cover plate assembly 220, ensuring the installation stability of the cover plate assembly 220. The crimping portion 31 can also separate the cover plate assembly 220 and the electrode assembly 120, thereby further ensuring that the cover plate assembly 220 is not connected to the electrode assembly 120, and thus achieving the de-energization of the cover plate assembly 220. In addition, the overall structure is relatively simple and easy to implement.

[0049] Specifically, the crimping portion 31 may include two straight portions 31A arranged parallel to the surface 90s of the cover substrate 90 (i.e., extending in the direction X), and a bent portion 31B connecting the two straight portions 31A. The area where the cover substrate 90 and the straight portion 31A overlap in the direction Z can be referred to as a sealing area, and the size of the sealing area in the direction X is referred to as a sealing width b. In some embodiments, the edge of the insulating layer 93 can be located between the cover substrate 90 and the straight portion 31A in the direction Z, that is, the edge of the insulating layer 93 extends into the sealing area. By arranging the edge of the insulating layer 93 in the sealing area, it can be ensured that the electrolyte does not enter between the insulating layer 93 and the cover substrate 90 through the edge of the insulating layer 93, thereby isolating the electrolyte well and effectively preventing the cover substrate 90 from being corroded by the electrolyte.

[0050] Furthermore, the edge of the cover assembly 220 and the crimping portion 31 and the curling portion 32 of the housing 200 are typically covered by a sealing ring 80. By positioning the edge of the insulating layer 93 within the sealing area, the insulating layer 93 and the sealing ring 80 can jointly seal between the metal cover base 90 and the housing 200, further improving the sealing effect.

[0051] In some embodiments, the sealing width b may be greater than 1 mm. In some embodiments, the distance a between the edge of the insulating layer 93 and the edge of the cover substrate 90 may be greater than or equal to 0.5 mm and less than or equal to 5 mm (5 mm ≥ a ≥ 0.5 mm). The difference between the sealing width b and the distance a may correspond to the width of the portion of the insulating layer 93 located in the sealing area, that is, the width of the portion of the insulating layer 93 entering the sealing area. In some embodiments, the difference between the sealing width b and the distance a may range from 0.5 mm to 3 mm (i.e., 0.5 mm ≤ b ≤ 3 mm). In other words, the width of the portion of the insulating layer 93 entering the sealing area ranges from 0.5 mm to 3 mm. Such a width setting can ensure that the insulating layer 93 extends an appropriate distance into the sealing area to achieve good sealing and anti-corrosion effects, and can avoid waste of material by setting too many insulating layers in the sealing area.

[0052] In one exemplary embodiment, a method for forming a secondary battery may include the following steps: first, stamping a cover plate substrate 90 from a low-carbon steel strip, wherein the low-carbon steel strip is nickel-plated to form a metal layer (nickel-plated layer) before stamping the cover plate substrate 90; second, after stamping the cover plate substrate 90, its surface is degreased and cleaned, and UV glue is sprayed on a defined area of ​​the surface 90s of the cover plate substrate 90 facing the interior of the battery, and irradiated with ultraviolet light to rapidly cure it to form a UV glue layer (insulating layer 93). The defined area may be a circular area, and the distance a between the edge of the defined UV glue layer area and the diameter edge of the cover plate substrate 90 is 1.5 mm. The thickness of the cured UV glue layer may be approximately 60 μm. Finally, the method for forming a secondary battery may further include forming a roll-grooved seal structure (crimping portion 31). After battery assembly, the sealing width of the sealing area is b = 3 mm, and the width of the UV glue layer entering the sealing area is ba = 1.5 mm.

[0053] In another exemplary embodiment, a method for forming a secondary battery may include the following steps: first, a low-carbon steel strip is used to stamp a cover plate substrate 90, and the low-carbon steel strip is not nickel-plated before stamping the cover plate substrate 90; second, after the cover plate substrate 90 is stamped, its surface is degreased and cleaned, and then barrel-plated with nickel to form a metal layer (nickel-plated layer), so that the cover plate substrate 90 itself has good rust resistance; then, a UV adhesive layer is sprayed on a limited area of ​​the surface of the cover plate substrate 90 facing the interior of the battery, and is rapidly cured using ultraviolet light to form a UV adhesive layer (insulating layer 93). The limited area may be a circular area, and the distance a between the edge of the limited UV adhesive layer and the edge of the cover plate substrate 90 in the diameter direction is 1 mm. The thickness of the cured UV adhesive layer may be approximately 35 μm. Finally, the method for forming a secondary battery further includes: forming a rolling groove sealing structure (pressing portion 31). After the battery is assembled, the sealing width of the sealing area is b=2.4 mm, and the width of the UV adhesive layer entering the sealing area is ba=1.4 mm.

[0054] After being processed in the above two example embodiments, the processing result is that the surface 90s of the cover substrate 90 facing the inside of the battery is covered with a UV glue layer, and the edge of the UV glue layer enters the sealing area, the product maintains good sealing, and at the same time, the surface parts in contact with the electrolyte are covered with the UV glue layer, which can effectively isolate the electrolyte and prevent the cover substrate 90 from being corroded by the electrolyte.

[0055] Moreover, the above-mentioned beneficial effects of the present application have been demonstrated through tests. In one test, the secondary battery provided by the present application (wherein the cover plate assembly includes the above-mentioned cover plate substrate, metal layer and insulating layer) was stored at high temperature, and the result was no abnormal voltage drop; and during the storage process, there was no corrosion and blackening on the surface of the cover plate assembly facing the inside of the secondary battery. In another test, the surface of the cover plate assembly covered with the UV adhesive layer was placed in a neutral salt spray for 2 hours, and there was no rust at all. In another test, the surface of the cover plate assembly covered with the UV adhesive layer was placed in an HTHH (High Temperature and High Humidity) environment of 85°C and 90% RH (Relative Humidity) for 6 days, and there was no rust. It can be seen that the present application can effectively prevent the cover plate assembly from being corroded by the electrolyte by providing an insulating layer such as a UV adhesive layer.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A secondary battery, characterized in that: include: electrode assembly; a housing for defining a housing for accommodating the electrode assembly, and having an opening; as well as a cover plate assembly, the cover plate assembly covering the opening of the housing to encapsulate the electrode assembly, wherein the cover plate assembly comprises: a cover plate substrate; and An insulating layer is located on a surface of the cover plate substrate facing the electrode assembly.

2. The secondary battery according to claim 1, wherein The surface of the cover plate base facing the electrode assembly has a notch, wherein the insulating layer covers the notch.

3. The secondary battery according to claim 1, wherein A metal layer is provided between the cover substrate and the insulating layer.

4. The secondary battery according to claim 1, wherein The distance between the edge of the insulating layer and the edge of the cover substrate is greater than or equal to 0.5 mm and less than or equal to 5 mm.

5. The secondary battery according to claim 1, wherein The insulating layer covers the entire surface of the cap plate base facing the electrode assembly.

6. The secondary battery according to claim 1, wherein The insulating layer is a UV-curable adhesive layer.

7. The secondary battery according to claim 1, wherein A pressing portion protruding inward is provided on a side wall of the housing adjacent to the opening, and the pressing portion includes a straight portion arranged parallel to the surface of the cover base. Wherein, the edge of the insulating layer is located between the straight portion and the cover plate base; The secondary battery is a cylindrical battery.

8. The secondary battery according to claim 7, wherein: The cover plate base is circular, and the area where the straight portion overlaps with the cover plate base in a direction perpendicular to the surface is a sealing area, wherein the portion of the insulating layer located in the sealing area has a width in the diameter direction of the cover plate base, and the width ranges from 0.5 mm to 3 mm.

9. A battery pack, characterized in that: The invention comprises the secondary battery according to any one of claims 1 to 8.

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

Images