Lower plastic, battery cover plate assembly and power battery

Abstract

The utility model provides lower plastic, a battery cover plate assembly and a power battery. The lower plastic comprises a body part; and the buckling part is arranged at the top of the body part, is used for being matched with a clamping hole in the light cover plate, can perform radial telescopic movement, has a diameter shrinkage state of radial shrinkage and a diameter expansion state of radial expansion, and performs radial telescopic movement so as to be switched between the diameter shrinkage state and the diameter expansion state. Due to the fact that the buckling part can stretch out and draw back in the radial direction, during installation, acting force is applied to the buckling part so that the buckling part can be switched from the diameter-expanding state to the diameter-reducing state, the buckling part can freely enter and exit from the clamping hole, the buckling part can be conveniently and rapidly installed in the clamping hole, and after the acting force applied to the buckling part is relieved, the buckling part can be fixed. When the lower plastic and the light cover plate are assembled, the buckling part is switched from the reducing state to the expanding state under the elastic force of the material of the buckling part, so that the buckling part is limited in the clamping hole, and the buckling part and the clamping hole are buckled together, and therefore, the lower plastic and the light cover plate are fixed together, the buckling difficulty of the lower plastic is reduced, and the assembling efficiency of the lower plastic can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a lower plastic, a battery cover assembly, and a power battery. Background Art

[0002] A power battery is a storage battery that provides power for electric vehicles, electric trains, electric bicycles, etc. As an important part of a power battery, the quality of the battery cover assembly directly affects the working performance of the power battery.

[0003] Chinese invention application with publication number CN116014316A discloses a battery cover and a manufacturing method, including a light cover plate, a positive pole column, a negative pole column, a sealing ring, an upper plastic for the positive pole, an upper plastic for the negative pole, and a lower plastic; two pole column holes are respectively provided on both sides in the length direction of the light cover plate, and a fixing ring is provided on the periphery of the light cover plate; the positive pole column and the negative pole column are respectively inserted into the two pole column holes, and the positive pole column and the negative pole column are fixed to the light cover plate through the sealing ring; the periphery of the positive pole column is coated with the upper plastic for the positive pole, and the periphery of the negative pole column is coated with the upper plastic for the negative pole; the lower plastic is fixed to the bottom of the light cover plate by a buckling method. However, in actual application, due to the structural design of the lower plastic, it takes a long time to buckle the lower plastic onto the light cover plate, and there is a problem of low assembly efficiency of the lower plastic. Utility Model Content

[0004] The embodiments of the present application provide a lower plastic, a battery cover assembly, and a power battery to solve the problems existing in the related art. The technical solutions are as follows:

[0005] In a first aspect, the embodiments of the present application provide a lower plastic, including:

[0006] A body part configured to be disposed at the bottom of a light cover plate; and

[0007] A buckle part provided on the top of the body part, the buckle part extending upward relative to the top of the body part, the buckle part being used to cooperate with a card hole on the light cover plate to connect the lower plastic and the light cover plate together. Among them, the buckle part can be radially telescoped, and the buckle part has a reduced-diameter state in which it radially contracts, so that the buckle part can move up and down into and out of the card hole. The buckle part also has an expanded-diameter state in which it radially expands to limit the buckle part in the card hole. The buckle part radially telescopes and switches between the reduced-diameter state and the expanded-diameter state.

[0008] In an embodiment, the buckle part has a through hole and a notch. The through hole penetrates through the buckle part both vertically, and the buckle part is arranged around the through hole. The notch penetrates through the top of the buckle part, and the notch penetrates through the buckle part both front and back. The notch communicates with the through hole.

[0009] In one embodiment, the notch extends from the bottom of the buckle portion to the top of the buckle portion.

[0010] In one embodiment, the number of notches is at least two, and the at least two notches are arranged around the perforation at intervals.

[0011] In one embodiment, the number of notches is two, and the two notches are symmetrically arranged about the axial center line of the perforation.

[0012] In one embodiment, the cross-sectional area of the notch gradually increases from bottom to top.

[0013] In one embodiment, the outer peripheral wall of the top of the buckle portion is provided with an installation guiding inclined surface. During the process of inserting the buckle portion into the card hole, the installation guiding inclined surface is used to abut against the hole wall of the card hole to push the buckle portion to switch from the expanded diameter state to the reduced diameter state.

[0014] In one embodiment, the buckle portion includes:

[0015] A connecting section, the bottom of the connecting section is connected to the top of the body portion, and the connecting section extends upward relative to the top of the body portion;

[0016] A clamping section, the clamping section is arranged on the outer peripheral wall of the top of the connecting section, and a clamping groove is formed between the bottom of the clamping section and the outer peripheral wall of the connecting section, and the clamping groove is used for buckling with a clamping protrusion in the card hole.

[0017] In one embodiment, the body portion and the buckle portion are integrally injection-molded;

[0018] And / or, the number of the buckle portions is two, and the two buckle portions are arranged at intervals along the length direction of the body portion.

[0019] In a second aspect, an embodiment of the present application provides a battery cover assembly, including:

[0020] A light cover plate, the light cover plate has a card hole; and

[0021] The above-mentioned lower plastic.

[0022] In a third aspect, an embodiment of the present application provides a power battery, including the above-mentioned lower plastic.

[0023] The advantages or beneficial effects in the above technical solutions at least include:

[0024] For the lower plastic of the present utility model, since the buckle portion can expand and contract radially, during installation, applying a force to the buckle portion can cause the buckle portion to switch from the expanded diameter state to the contracted diameter state, enabling the buckle portion to freely enter and exit the card hole, facilitating the quick insertion of the buckle portion into the card hole. After removing the force applied to the buckle portion, the buckle portion switches from the contracted diameter state to the expanded diameter state under the action of the elastic force inherent in its own material, realizing the restriction of the buckle portion in the card hole and fastening the buckle portion and the card hole together, thereby fixing the lower plastic and the optical cover plate together. Compared with the prior art, the buckling difficulty of the lower plastic is reduced, the assembly of the lower plastic is more convenient, facilitating automated production. At the same time, the assembly efficiency of the lower plastic can be improved.

[0025] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present application will be readily apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the drawings, unless otherwise specified, the same reference numerals throughout the several views denote the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0027] Figure 1 is a perspective structural view of the lower plastic of the present utility model;

[0028] Figure 2 is Figure 1 a partial enlarged view of A in

[0029] Figure 3 is a cross-sectional view of the battery cover plate assembly of the present utility model;

[0030] Figure 4 is Figure 3 a partial enlarged view of B in

[0031] REFERENCE NUMERALS

[0032] 1, body portion; 2, buckle portion; 21, perforation; 22, notch; 23, installation guiding inclined surface; 24, connecting section; 25, clamping section; 26, card slot; 3, optical cover plate; 31, card hole; 32, clamping projection; 33, fixing ring; 4, pole; 5, upper plastic; 6, sealing ring; 61, first annular portion; 62, second annular portion; 7, middle plastic. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] In the following text, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0034] See Figures 1-2 , which shows a lower plastic of a preferred embodiment of the present utility model, including:

[0035] A body part 1, which is used to be arranged at the bottom of the optical cover plate 3; and

[0036] A buckle part 2, which is arranged on the top of the body part 1. The buckle part 2 extends upward relative to the top of the body part 1. The buckle part 2 is used to cooperate with the card hole 31 on the optical cover plate 3 to connect the lower plastic and the optical cover plate 3 together. Among them, the buckle part 2 can radially expand and contract. The buckle part 2 has a reduced-diameter state in which it radially contracts, so that the buckle part 2 can move up and down in and out of the card hole 31. The buckle part 2 also has an expanded-diameter state in which it radially expands to limit the buckle part 2 in the card hole 31. The buckle part 2 radially expands and contracts and switches between the reduced-diameter state and the expanded-diameter state.

[0037] For the lower plastic of the present utility model, since the buckle part 2 can radially expand and contract, during installation, applying a force to the buckle part 2 can cause the buckle part 2 to switch from the expanded-diameter state to the reduced-diameter state, enabling the buckle part 2 to freely enter and exit the card hole 31, facilitating the quick installation of the buckle part 2 into the card hole 31. After removing the force applied to the buckle part 2, the buckle part 2 switches from the reduced-diameter state to the expanded-diameter state under the action of the elastic force inherent in its own material, realizing the restriction of the buckle part 2 in the card hole 31, and making the buckle part 2 and the card hole 31 snap together, thereby fixing the lower plastic and the optical cover plate 3 together. Compared with the prior art, it reduces the buckling difficulty of the lower plastic, makes the assembly of the lower plastic more convenient, facilitates automated production, and at the same time, can improve the assembly efficiency of the lower plastic.

[0038] See Figures 1-2 , in one embodiment, the buckle part 2 has a through hole 21 and a notch 22. The through hole 21 penetrates through the buckle part 2 both vertically. And the buckle part 2 is arranged around the through hole 21. The notch 22 penetrates through the top of the buckle part 2, and the notch 22 penetrates through the buckle part 2 both front and back. The notch 22 communicates with the through hole 21. The setting of the through hole 21 can make the buckle part 2 form an annular structure with a relatively thin wall thickness, providing a basis for the radial movement of the buckle part 2. At the same time, the setting of the notch 22 can enable the buckle part 2 to radially contract and move, so that the buckle part 2 can switch between the reduced-diameter state and the expanded-diameter state. At the same time, the settings of the through hole 21 and the notch 22 do not weaken the structural strength of the buckle part 2, ensuring that the buckle part 2 can still be reliably snapped together with the card hole 31. The structure is simple and practical, with low cost and high connection reliability.

[0039] See Figures 1-2 , in one embodiment, the notch 22 extends from the bottom to the top of the buckle portion 2, so as to reduce the difficulty of radial expansion and contraction of the buckle portion 2, make the radial expansion and contraction of the buckle portion 2 smoother, further reduce the buckling difficulty of the lower plastic, and be conducive to further improving the assembly efficiency of the lower plastic.

[0040] See Figures 1-2 , in one embodiment, the number of the notches 22 is at least two, and the at least two notches 22 are arranged at intervals around the through hole 21, so as to divide the buckle portion 2 into at least two parts arranged at intervals around the through hole 21, make the radial expansion and contraction movement of the buckle portion 2 smoother, and be conducive to further improving the assembly efficiency of the lower plastic.

[0041] See Figures 1-2 , in this embodiment, the number of the notches 22 is two, and the two notches 22 are symmetrically arranged about the axial center line of the through hole 21, so as to divide the buckle portion 2 into two parts arranged at intervals around the through hole 21, make the radial expansion and contraction movement of the buckle portion 2 smoother, be conducive to further improving the assembly efficiency of the lower plastic. At the same time, the structural strength of the buckle portion 2 will not be weakened, so that the buckle portion 2 can be reliably buckled with the card hole 31, and it is conducive to further improving the assembly stability of the lower plastic.

[0042] Of course, in other embodiments, the number of the notches 22 can be one, three or more, and can be specifically set according to actual needs.

[0043] In other embodiments, the through hole 21 can be only provided on the buckle portion 2, and at the same time, the buckle portion 2 is arranged as a thin-walled structure, and the buckle portion 2 can also be switched between the reduced-diameter state and the expanded-diameter state.

[0044] See Figures 1-2 , in one embodiment, the cross-sectional area of the notch 22 gradually increases from bottom to top, so that the notch 22 forms a structure with a narrow bottom and a wide top. The narrow notch 22 at the bottom can keep a large contact area between the buckle portion 2 and the body portion 1, so that the buckle portion 2 and the body portion 1 are reliably connected together, which is conducive to further increasing the connection stability between the buckle portion 2 and the card hole 31. The wide notch 22 at the top can increase the circumferential distance between at least two parts of the buckle portion 2, make the radial expansion and contraction movement of the buckle portion 2 smoother, and be conducive to further improving the assembly efficiency of the lower plastic.

[0045] Of course, in other embodiments, the cross-section of the notch 22 is equal everywhere from bottom to top, that is, the notch 22 is a rectangular structure.

[0046] See Figures 2-4, in one embodiment, an installation guiding slope 23 is provided on the outer peripheral wall of the top of the buckle portion 2. During the process of inserting the buckle portion 2 into the card hole 31, the installation guiding slope 23 is used to abut against the hole wall of the card hole 31 to push the buckle portion 2 to switch from the expanded diameter state to the reduced diameter state. That is, the force for pushing the clamping portion to switch from the expanded diameter state to the reduced diameter state can come from the force generated by the abutment of the installation guiding slope 23 and the hole wall of the card hole 31, without the need to apply an additional force to the buckle portion 2 during the installation process, making the installation operation of the buckle portion 2 simpler and more convenient, which is conducive to further improving the assembly efficiency of the lower plastic. At the same time, the setting of the installation guiding slope 23 can also play an installation guiding role, which is conducive to further improving the installation smoothness of the buckle portion 2, thereby further improving the assembly efficiency of the lower plastic.

[0047] See Figures 2-4 , in one embodiment, the buckle portion 2 includes:

[0048] A connecting section 24, the bottom of the connecting section 24 is connected to the top of the main body portion 1, and the connecting section 24 extends upward relative to the top of the main body portion 1;

[0049] A clamping section 25, the clamping section 25 is arranged on the outer peripheral wall of the top of the connecting section 24, and a clamping groove 26 is formed between the bottom of the clamping section 25 and the outer peripheral wall of the connecting section 24. The clamping groove 26 is used to engage with the clamping protrusion 32 in the card hole 31 to reliably engage the buckle portion 2 and the card hole 31 together, which is conducive to improving the assembly stability of the buckle portion 2, thereby enabling the lower plastic and the optical cover plate 3 to be reliably assembled together.

[0050] In one embodiment, the main body portion 1 and the buckle portion 2 are integrally injection-molded, so that the buckle portion 2 and the main body portion 1 are reliably connected together, which is conducive to further increasing the connection stability between the buckle portion 2 and the card hole 31.

[0051] In one embodiment, the number of the buckle portions 2 is two, and the two buckle portions 2 are arranged at intervals along the length direction of the main body portion 1. Each buckle portion 2 is respectively engaged with a corresponding card hole 31 to further improve the assembly stability of the lower plastic and the optical cover plate 3.

[0052] See Figures 3-4 , which shows a battery cover plate assembly in a preferred embodiment of the present invention, including:

[0053] An optical cover plate 3, the optical cover plate 3 has a card hole 31; and

[0054] The above-mentioned lower plastic.

[0055] For the battery cover plate assembly of the present utility model, due to the adoption of the above-mentioned lower plastic, and also because the buckle portion 2 can radially expand and contract, during installation, applying a force to the buckle portion 2 can cause the buckle portion 2 to switch from the expanded diameter state to the contracted diameter state, enabling the buckle portion 2 to freely enter and exit the card hole 31, facilitating the quick insertion of the buckle portion 2 into the card hole 31. After removing the force applied to the buckle portion 2, the buckle portion 2 switches from the contracted diameter state to the expanded diameter state under the action of the elastic force inherent in its own material, realizing the restriction of the buckle portion 2 in the card hole 31, and making the buckle portion 2 and the card hole 31 snap together, thereby fixing the lower plastic and the optical cover plate 3 together. Compared with the prior art, the buckling difficulty of the lower plastic is reduced, the assembly of the lower plastic is more convenient, facilitating automated production, and at the same time, the assembly efficiency of the lower plastic can be improved.

[0056] See Figures 3-4 , the optical cover plate 3 further has a mounting hole, the mounting hole is located above the card hole 31 and is coaxially arranged with the card hole 31, and the mounting hole communicates with the card hole 31;

[0057] The battery cover plate assembly further includes:

[0058] A pole column 4, the pole column 4 is inserted through the mounting hole;

[0059] An upper plastic 5, the upper plastic 5 is press-connected between the optical cover plate 3 and the pole column 4;

[0060] Sealing ring 6 is provided with a first annular part 61 and a second annular part 62. The first annular part 61 is arranged around the axial center line of the mounting hole. The first annular part 61 is clamped between the bottom wall of the mounting hole and the bottom of the pole column 4. The second annular part 62 is arranged on the outer peripheral wall of the first annular part 61. The second annular part 62 is arranged around the first annular part 61. A first groove is formed between the top of the second annular part 62 and the upper outer peripheral wall of the first annular part 61. A second groove is formed between the bottom of the second annular part 62 and the lower outer peripheral wall of the first annular part 61. The second annular part 62 is clamped between the side wall of the mounting hole and the bottom of the pole column 4. Since the upper plastic 5 is crimped between the optical cover plate 3 and the upper part of the pole column 4, at the same time, the first annular part 61 is clamped between the bottom wall of the mounting hole and the bottom of the pole column 4 to limit the axial movement of the pole column 4, so as to realize the insulating fixation of the pole column 4. There is no need to form a pole column 4 ring nor to weld the pole column 4. The assembly process is less, and the assembly efficiency can be effectively improved. At the same time, a first groove is formed between the top of the second annular part 62 and the upper outer peripheral wall of the first annular part 61 and a second groove is formed between the bottom of the second annular part 62 and the lower outer peripheral wall of the first annular part 61, which can play a role in thinning the second annular part 62, realizing the reduction of the compression difficulty of the second annular part 62, enabling the second annular part 62 to be reliably clamped between the side wall of the mounting hole and the bottom of the pole column 4, ensuring that the second annular part 62 is in close contact with the side wall of the mounting hole and the bottom of the second annular part 62 is in close contact with the bottom of the pole column 4, so as to reliably seal the gap between the pole column 4 and the optical cover plate 3, avoiding problems such as incomplete compression of the sealing ring 6, deviation of the sealing ring 6, air leakage, etc., and improving the sealing reliability. In addition, a second groove is formed between the bottom of the second annular part 62 and the lower outer peripheral wall of the first annular part 61, which can play a role in avoiding the sealing ring 6 and the optical cover plate 3, avoiding the problem of assembly interference between the sealing ring 6 and the optical cover plate 3.

[0061] In an embodiment, the bottom wall of the mounting hole has an annular groove, and the bottom of the first annular part 61 is provided with an annular protrusion (not shown in the figure). The annular protrusion and the annular groove are adapted to increase the contact area between the sealing ring 6 and the hole wall of the mounting hole, and further improve the airtightness of the battery cover plate assembly.

[0062] See Figures 3-4 , in an embodiment, the battery cover plate assembly further includes:

[0063] Middle plastic 7 is clamped between the side wall of the mounting hole and the lower outer peripheral wall of the pole column 4 to limit the radial movement of the pole column 4, which can further improve the assembly stability of the pole column 4 and at the same time improve the insulating reliability of the pole column 4.

[0064] In one embodiment, the outer diameter of the lower part of the terminal post 4 is larger than that of the upper part of the terminal post 4. The middle plastic 7 covers the lower part of the terminal post 4 to increase the contact area between the middle plastic 7 and the terminal post 4, so that the connection between the middle plastic 7 and the terminal post 4 is more reliable, and the assembly stability of the terminal post 4 can be further improved.

[0065] See Figure 4 , in one embodiment, the top of the second annular portion 62 also abuts against the bottom of the middle plastic 7. Since the middle plastic 7 covers the lower part of the terminal post 4, it is equivalent to increasing the outer diameter of the lower part of the terminal post 4. Therefore, by abutting the top of the second annular portion 62 against the bottom of the middle plastic 7, it is equivalent to increasing the contact area between the second annular portion 62 and the bottom of the terminal post 4, making the second annular portion 62 and the bottom of the terminal post 4 fit tightly, which is beneficial to further improving the sealing performance. At the same time, it is also beneficial to improve the insulation performance of the battery cover plate assembly.

[0066] See Figure 4 , in one embodiment, the upper plastic 5 is provided with an extension portion, and the extension portion is clamped between the side wall of the mounting hole and the outer peripheral wall of the middle part of the terminal post 4 to increase the contact area between the upper plastic 5 and the terminal post 4, which is beneficial to further improving the assembly stability of the terminal post 4. At the same time, it can also improve the insulation performance of the terminal post 4.

[0067] See Figure 4 , in one embodiment, the bottom of the extension portion abuts against the top of the middle plastic 7 to further improve the insulation performance of the battery cover plate assembly.

[0068] In one embodiment, the top of the middle plastic 7 has a plurality of third grooves, and the plurality of third grooves are arranged around the axial center line of the mounting hole, and the extension portion covers the top of the middle plastic 7. Since the middle plastic 7 covers the lower part of the terminal post 4 and the extension portion on the upper plastic 5 covers the top of the middle plastic 7, it is equivalent to increasing the contact area between the upper plastic 5 and the terminal post 4. At the same time, due to the plurality of third grooves on the top of the middle plastic 7 and the extension portion on the upper plastic 5 covering the top of the middle plastic 7, part of the extension portion extends into the plurality of third grooves, which can play a role in preventing the terminal post 4 from rotating, and is beneficial to further improving the assembly stability of the terminal post 4.

[0069] In one embodiment, the top of the optical cover plate 3 is provided with a fixing ring 33. The fixing ring 33 is arranged around the top opening of the mounting hole, and the fixing ring 33 is bent towards the axial center line of the mounting hole. The upper plastic 5 covers the fixing ring 33 to increase the contact area between the upper plastic 5 and the terminal post 4, which is beneficial to further improving the assembly stability of the terminal post 4.

[0070] In one embodiment, the number of the fixing rings 33 is multiple, and the multiple fixing rings 33 are arranged at intervals around the axial center line of the mounting hole, so that a part of the upper plastic 5 is filled between the adjacent fixing rings 33, which can reliably fix the upper plastic 5 to the optical cover plate 3. At the same time, it is beneficial to further improve the assembly stability of the pole column 4.

[0071] A preferred embodiment of the present utility model provides a power battery, including the above-mentioned lower plastic.

[0072] For the battery cover plate assembly of the present utility model, due to the adoption of the above-mentioned lower plastic, and also because the buckle part 2 can radially expand and contract, during installation, applying a force to the buckle part 2 can cause the buckle part 2 to switch from the expanded diameter state to the contracted diameter state, enabling the buckle part 2 to freely enter and exit the card hole 31, facilitating the quick loading of the buckle part 2 into the card hole 31. After removing the force applied to the buckle part 2, the buckle part 2 switches from the contracted diameter state to the expanded diameter state under the action of the elastic force inherent in its own material, realizing the restriction of the buckle part 2 in the card hole 31, and making the buckle part 2 and the card hole 31 snap together, thereby fixing the lower plastic and the optical cover plate 3 together. Compared with the prior art, the buckling difficulty of the lower plastic is reduced, the assembly of the lower plastic is more convenient, facilitating automated production, and at the same time, the assembly efficiency of the lower plastic can be improved.

[0073] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0074] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In the description of the present application, "a plurality of" means two or more, unless otherwise specifically defined.

[0075] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various changes or substitutions, and these should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. Lower plastic, characterized in that, Comprising: A body part configured to be disposed at the bottom of the optical cover plate; And A buckle part provided on the top of the body part, the buckle part extending upward relative to the top of the body part, the buckle part being used for cooperating with a card hole on the optical cover plate to connect the lower plastic and the optical cover plate together, wherein the buckle part can be radially telescoped, the buckle part has a reduced diameter state in which the diameter is radially contracted, so that the buckle part can move up and down in and out of the card hole, the buckle part also has an expanded diameter state in which the diameter is radially expanded to limit the buckle part in the card hole, and the buckle part is radially telescoped to switch between the reduced diameter state and the expanded diameter state.

2. The lower plastic according to claim 1, characterized in that, The buckle part has a perforation and a notch, the perforation penetrates through the buckle part both vertically, and the buckle part is arranged around the perforation, the notch penetrates through the top of the buckle part, the notch penetrates through the buckle part both front and back, and the notch communicates with the perforation.

3. The lower plastic according to claim 2, wherein The notch extends from the bottom of the buckle part to the top of the buckle part.

4. The lower plastic according to claim 2, characterized in that, The number of the notches is at least two, and at least two of the notches are arranged at intervals around the perforation.

5. The lower plastic according to claim 2, wherein The cross-sectional area of the notch gradually increases from bottom to top.

6. The lower plastic according to claim 1, wherein An installation guiding inclined surface is provided on the outer peripheral wall of the top of the buckle part, and during the process of inserting the buckle part into the card hole, the installation guiding inclined surface is used for abutting against the hole wall of the card hole to push the buckle part to switch from the expanded diameter state to the reduced diameter state.

7. The lower plastic according to claim 1, characterized in that, The buckle part includes: A connecting section, the bottom of the connecting section is connected to the top of the body part, and the connecting section extends upward relative to the top of the body part; A clamping section provided on the outer peripheral wall of the top of the connecting section, a clamping groove is formed between the bottom of the clamping section and the outer peripheral wall of the connecting section, and the clamping groove is used for clamping and engaging with a clamping protrusion in the card hole.

8. The lower plastic according to claim 1, wherein The body part and the buckle part are integrally injection molded; And / or, the number of the buckle parts is two, the two buckle parts are arranged at intervals along the length direction of the body part, and each buckle part is respectively clamped and engaged with a corresponding card hole.

9. Battery cover assembly, characterized in that, Comprising: An optical cover plate having a card hole; And The lower plastic according to any one of claims 1-8, wherein the buckle part is clamped and engaged with the card hole.

10. Power battery, characterized in that, Comprising the lower plastic according to any one of claims 1-8.

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