Lower plastic, battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a lower plastic, a battery cell and a battery pack, the lower plastic comprises a plastic body, the plastic body is suitable for being connected with a cover plate of the battery cell, the cover plate is provided with a liquid injection hole, and the part, corresponding to the liquid injection hole, of the plastic body extends towards the direction far away from the cover plate to form a protruding part; at least one through hole is formed in the side, opposite to the liquid injection hole, of the protruding part, and the through hole communicates with the liquid injection hole. According to the lower plastic provided by the utility model, the plastic body is provided with the convex part for shielding the liquid injection hole, when electrolyte is injected into a battery cell through the liquid injection hole, the impact of the electrolyte is buffered by the convex part after the electrolyte passes through the liquid injection hole, and the electrolyte flows into the battery cell through the through hole in the convex part after being buffered, so that the battery cell is prevented from being damaged. The electrolyte can be effectively prevented from directly impacting the pole group in the battery cell, the pole group is prevented from being damaged, and the electrolyte injection stability is ensured, so that the safety and the reliability of the battery cell are improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to plastic, battery cells, and battery packs. Background Technology

[0002] With the development of new energy technologies, battery packs are increasingly being used in various new energy products. A battery pack typically contains multiple cells, and each cell generally includes a housing, multiple electrode groups disposed within the housing, and a cover plate assembly disposed on the top of the housing and electrically connected to the electrode groups.

[0003] The cover plate assembly includes a cover plate, an injection hole on the cover plate, and an explosion-proof valve. To prevent the cover plate from conducting electricity in contact with the electrode assembly, a lower plastic seal is provided between the cover plate and the electrode assembly for insulation.

[0004] During the cell manufacturing process, electrolyte needs to be injected into the cell through the injection hole on the cover plate. In order to improve the injection efficiency, the injection pressure is generally high during the injection process. The electrolyte can easily impact the electrode diaphragm, causing the diaphragm to fold, the electrode assembly to be damaged, and the electrode assembly to short circuit, ultimately resulting in poor cell safety. Utility Model Content

[0005] In view of this, the present invention provides a plastic substrate, a battery cell, and a battery pack to solve the problem that when electrolyte is added to the battery cell, the electrolyte easily impacts the electrode separator, causing damage to the electrode assembly, or even causing a short circuit in the electrode assembly, ultimately resulting in poor safety of the battery cell.

[0006] In a first aspect, the present invention provides a lower plastic, comprising: a plastic body adapted to be connected to a cover plate of a battery cell, the cover plate having an injection hole, the portion of the plastic body corresponding to the injection hole extending away from the cover plate to form a protrusion, the protrusion having at least one through hole on the side opposite to the injection hole, the through hole communicating with the injection hole.

[0007] Beneficial effects: The plastic body of this utility model has a protrusion that blocks the injection hole. When electrolyte is added to the battery cell through the injection hole, the protrusion buffers the impact of the electrolyte after it passes through the injection hole. After buffering, the electrolyte flows into the battery cell through the through hole on the protrusion, effectively preventing the electrolyte from directly impacting the electrode assembly inside the battery cell, avoiding damage to the electrode assembly, ensuring injection stability, thereby improving the safety and reliability of the battery cell. It also helps reduce the risk of leakage from the injection hole and lowers usage costs. Moreover, the protrusion is located on the side of the plastic body away from the cover plate, so it does not affect the connection between the plastic body and the cover plate, facilitating the assembly of the battery cell.

[0008] In one alternative embodiment, the protrusion is inclined downwards on the side of the through hole facing the plastic body.

[0009] Beneficial effects: By tilting the plate surface with the through hole on the protruding part downwards towards the plastic body, the inclined surface can enhance the buffering effect on the electrolyte and further improve the stability of electrolyte injection.

[0010] In one alternative embodiment, the protrusion has a conical shape on the side with the through hole that protrudes toward the injection hole.

[0011] Beneficial effects: Designing the side of the protrusion with the through hole in a conical shape facilitates the flow of electrolyte into the cell and prevents reverse flow of electrolyte, which could lead to leakage and contamination of the injection hole. Furthermore, the conical shape provides higher structural strength, which helps improve the pressure resistance of the protrusion.

[0012] In one optional embodiment, the inclination angle θ between the side of the protrusion having the through hole and the sidewall of the protrusion satisfies 5°≤θ<90°.

[0013] Beneficial effects: By limiting the range of the tilt angle θ, it is easy to accurately control the flow direction of the electrolyte, ensuring that the electrolyte is accurately injected into the cell along the preset path, avoiding excessive diffusion of the electrode liquid after passing through the through hole, and further improving the electrolyte injection efficiency and safety of the cell. If the tilt angle θ is too small, electrolyte will remain at the protrusion.

[0014] In one alternative embodiment, when multiple through holes are provided, the multiple through holes are circumferentially spaced on the side of the protrusion opposite to the injection hole.

[0015] Beneficial effects: Setting multiple through holes along the circumference of the protrusion facilitates the uniform passage of electrolyte through multiple through holes, evenly dispersing the injection pressure, improving injection stability, and preventing irregular flow of electrolyte within the cell.

[0016] In one optional embodiment, the total opening area of ​​the plurality of through holes is greater than or equal to the opening area of ​​the injection hole.

[0017] Beneficial effects: Since the total area of ​​the multiple through holes is greater than or equal to the area of ​​the injection hole, the electrolyte pressure is reduced after passing through the injection hole and then through the multiple through holes. This avoids excessive electrolyte pressure from impacting the electrode diaphragm and also prevents leakage.

[0018] In one optional embodiment, the height H of the protrusion satisfies 2mm < H ≤ 10mm.

[0019] Beneficial effects: By limiting the height of the protrusion, the buffering effect of the protrusion on the electrolyte can be ensured, and sufficient vertical space is left during the electrolyte injection process. If the height of the protrusion is too large, it is easy to interfere with the electrode assembly and hinder the installation between the cover plate and the housing. If the height of the protrusion is too small, the buffering effect on the electrolyte will be poor.

[0020] In one alternative embodiment, the wall thickness T of the protrusion satisfies 0.4mm < T ≤ 1.5mm.

[0021] Beneficial effects: By limiting the wall thickness of the protrusion, sufficient structural strength can be ensured to withstand the impact of the electrolyte, achieving a buffering effect. If the wall thickness of the protrusion is too small, it is easily damaged by the impact of the electrolyte; if the wall thickness is too large, it will shrink and deform during injection molding and occupy more space.

[0022] Secondly, this utility model also provides a battery cell, comprising:

[0023] The casing has an opening on one side;

[0024] A cover plate is placed over the opening and has an injection hole;

[0025] The aforementioned lower plastic body is located inside the cover plate, and the protrusion of the plastic body is correspondingly arranged with the injection hole.

[0026] Beneficial effects: Because the battery cell includes a lower plastic core, it has the same effect as the lower plastic core, namely, the lower plastic core has a protrusion that blocks the electrolyte injection hole. When electrolyte is added to the battery cell through the injection hole, the protrusion buffers the impact of the electrolyte after it passes through the injection hole. After buffering, the electrolyte flows into the battery cell through the through-hole on the protrusion. This effectively prevents the electrolyte from directly impacting the electrode assembly inside the battery cell, avoiding damage to the electrode assembly, ensuring electrolyte injection stability, thereby improving the safety and reliability of the battery cell. It also helps reduce the risk of electrolyte leakage from the injection hole and lowers usage costs. Moreover, the protrusion is located on the side of the plastic core away from the cover plate, so it does not affect the connection between the plastic core and the cover plate, facilitating battery cell assembly.

[0027] Thirdly, the present invention also provides a battery pack, comprising: at least one of the above-mentioned battery cells.

[0028] Beneficial effects: The battery pack of this utility model has a protrusion on the lower plastic body that blocks the electrolyte injection hole. When electrolyte is added to the cell through the injection hole, the protrusion buffers the impact of the electrolyte after it passes through the injection hole. After buffering, the electrolyte flows into the cell through the through hole on the protrusion. This effectively prevents the electrolyte from directly impacting the electrode assembly inside the cell, avoiding damage to the electrode assembly, ensuring electrolyte injection stability, thereby improving the safety and reliability of the cell. It also helps reduce the risk of leakage from the injection hole and lowers usage costs. Moreover, the protrusion is located on the side of the plastic body away from the cover plate, so it does not affect the connection between the plastic body and the cover plate, facilitating cell assembly. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a top view of an embodiment of the present utility model showing the assembly of a lower plastic sheet and a cover plate.

[0031] Figure 2 for Figure 1 Cross-sectional view at point AA;

[0032] Figure 3 for Figure 2 A magnified view of a section at point B in the middle;

[0033] Figure 4 This is a bottom view of an embodiment of the present utility model showing the assembly of a lower plastic sheet and a cover plate.

[0034] Figure 5 This is a schematic diagram of the structure of a lower plastic material according to an embodiment of the present utility model;

[0035] Figure 6 This is a top view of a lower plastic material according to an embodiment of the present utility model;

[0036] Figure 7 This is a front view of a lower plastic material according to an embodiment of the present utility model.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Plastic body; 2. Cover plate; 201. Injection hole; 3. Protrusion; 301. Through hole; 4. Positive terminal; 5. Negative terminal; 6. Explosion-proof valve. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0040] The following is combined with Figures 1 to 7 The following describes embodiments of the present invention.

[0041] According to embodiments of the present invention, on the one hand, such as Figure 1 and Figure 2 As shown, a lower plastic is provided, including: a plastic body 1, the plastic body 1 being adapted to be connected to a cover plate 2 of a battery cell, the cover plate 2 having an injection hole 201, the portion of the plastic body 1 corresponding to the injection hole 201 extending away from the cover plate 2 to form a protrusion 3, the protrusion 3 having at least one through hole 301 on the side opposite to the injection hole 201, the through hole 301 communicating with the injection hole 201.

[0042] Therefore, the lower plastic body 1 provided in this embodiment of the present invention has a protrusion 3 that blocks the injection hole 201. When electrolyte is added to the battery cell through the injection hole 201, the protrusion 3 buffers the impact of the electrolyte after it passes through the injection hole 201. After buffering, the electrolyte flows into the battery cell through the through hole 301 on the protrusion 3. This effectively prevents the electrolyte from directly impacting the electrode assembly inside the battery cell, avoiding damage to the electrode assembly, ensuring the stability of the electrolyte injection, thereby improving the safety and reliability of the battery cell. It also helps to reduce the risk of leakage from the injection hole 201 and reduce the cost of use. Moreover, the protrusion 3 is located on the side of the plastic body 1 away from the cover plate 2, so it will not affect the connection between the plastic body 1 and the cover plate 2, which facilitates the assembly of the battery cell.

[0043] Compared to placing the through hole 301 on the side wall of the protrusion 3, this invention places the through hole 301 on the side of the protrusion 3 opposite to the injection hole 201, which ensures that the electrolyte is injected into the cell in a straight line, allowing the electrolyte to flow along a preset path and improving injection efficiency. Additionally, as... Figure 5 As shown, the sidewall of the protrusion 3 of this utility model is a solid structure, which has good structural strength, can effectively withstand the impact of electrolyte, and has a long service life.

[0044] Specifically, the plastic body 1 is sheet-shaped and fixedly connected to the cover plate 2. The plastic body 1 and the protrusion 3 are integrally formed, for example, by injection molding. The protrusion 3 and the cover plate 2 form a non-sealed receiving space. The projection of this receiving space in the height direction of the cover plate 2 covers the injection hole 201 to leave sufficient buffer space. The through hole 301 can adopt a guide draft design. The through hole 301 is located below the injection hole 201. The protrusion 3 can be columnar, for example, cylindrical, with an opening on the outer side of the protrusion 3 communicating with the injection hole 201, and the sidewall is perpendicular to the plastic body 1.

[0045] Specifically, after the cover plate 2 of the battery cell is installed with the battery cell housing, the cover plate 2 is located on the outer side, and the plastic body 1 is located on the inner side, that is, the protrusion 3 extends inward. In this embodiment of the present invention, the "inner" and "outer" directions are as follows: Figure 2 As shown. The side of the protrusion 3 opposite to the injection hole 201 is the inner side of the protrusion 3, which is also the bottom side of the protrusion 3.

[0046] It should be noted that the shape of the through hole 301 is not limited in this embodiment of the utility model. Any existing shape can be selected as needed. For example, the through hole 301 can be a round hole, a strip hole, an elliptical hole, etc.

[0047] In one embodiment, such as Figure 3 As shown, the side of the protrusion 3 with the through hole 301 is inclined downwards towards the plate surface of the plastic body 1. Inclining the side of the protrusion 3 with the through hole 301 towards the plate surface of the plastic body 1 can improve the buffering effect on the electrolyte by utilizing the inclined surface, thereby further improving the stability of electrolyte injection.

[0048] In this embodiment of the utility model, the "up" and "down" directions are as follows: Figure 2 As shown.

[0049] Furthermore, in one embodiment, such as Figure 3 As shown, the side of the protrusion 3 with the through hole 301 is tapered, protruding towards the injection hole 201. Setting the side of the protrusion 3 with the through hole 301 in a tapered shape facilitates the flow of electrolyte into the cell and prevents reverse flow of electrolyte, which could lead to leakage and contamination of the injection hole 201. Furthermore, the tapered structure has higher structural strength, which helps improve the pressure resistance of the protrusion 3.

[0050] Specifically, the conical central region is a platform, with the platform's perimeter set at a relative angle. This platform is located directly below the injection hole 201 and directly bears the injection pressure. After the electrolyte passes through the injection hole 201, it first impacts this platform, then flows downwards along the conical surface and enters the battery cell through the through hole 301.

[0051] Furthermore, in one embodiment, such as Figure 3As shown, the inclination angle θ between the side of the protrusion 3 with the through hole 301 and the sidewall of the protrusion 3 satisfies 5° ≤ θ < 90°. For example, the inclination angle θ between the side of the protrusion 3 with the through hole 301 and the sidewall of the protrusion 3 can be 5°, 10°, 20°, 40°, 45°, 65°, 80°, etc. By limiting the range of the inclination angle θ, it is convenient to accurately control the flow direction of the electrolyte, ensuring that the electrolyte is accurately injected into the battery cell along the preset path, avoiding excessive diffusion of the electrode liquid after passing through the through hole 301, and further improving the electrolyte injection efficiency and safety of the battery cell. If the inclination angle θ is less than 5°, electrolyte will remain at the protrusion 3.

[0052] Furthermore, in one embodiment, the inclination angle θ between the side of the protrusion 3 with the through hole 301 and the sidewall of the protrusion 3 satisfies 10°≤θ≤70°.

[0053] It should be noted that the number of through holes 301 in this embodiment of the utility model is not limited, and one, two or more can be selected as needed.

[0054] In one embodiment, such as Figures 4 to 6 As shown, when multiple through holes 301 are provided, the multiple through holes 301 are circumferentially spaced on the side of the protrusion 3 opposite to the injection hole 201. Arranging the multiple through holes 301 circumferentially on the protrusion 3 facilitates the uniform passage of electrolyte through the multiple through holes 301, evenly distributing the injection pressure, improving injection stability, and preventing irregular flow of electrolyte within the battery cell.

[0055] In one embodiment, the total opening area of ​​the plurality of through holes 301 is greater than or equal to the opening area of ​​the injection hole 201. Since the total opening area of ​​the plurality of through holes 301 is greater than or equal to the opening area of ​​the injection hole 201, the electrolyte first passes through the injection hole 201 and then through the plurality of through holes 301, resulting in a reduced injection pressure. This prevents excessive electrolyte pressure from impacting the electrode assembly diaphragm and also prevents leakage. Simultaneously, it ensures rapid injection, shortens injection time, and improves injection efficiency.

[0056] In one embodiment, such as Figure 3 and Figure 7 As shown, the height H of the protrusion 3 satisfies 2mm < H ≤ 10mm. For example, the height H of the protrusion 3 can be 2mm, 3mm, 5mm, 7mm, 10mm, etc. By limiting the height of the protrusion 3, the buffering effect of the protrusion 3 on the electrolyte can be ensured, and sufficient vertical space can be left during the electrolyte injection process. If the height H of the protrusion 3 is greater than 10mm, it is easy to interfere with the electrode assembly, which will hinder the installation between the cover plate 2 and the shell. If the height H of the protrusion 3 is less than 2mm, the buffering effect on the electrolyte will be poor.

[0057] Furthermore, in one embodiment, the height H of the protrusion 3 satisfies 4mm≤H≤8mm.

[0058] In one embodiment, such as Figure 3 As shown, the wall thickness T of the protrusion 3 satisfies 0.4mm < T ≤ 1.5mm. For example, the wall thickness T of the protrusion 3 can be 0.4mm, 0.5mm, 1mm, 1.2mm, 1.5mm, etc. By limiting the wall thickness of the protrusion 3, it can be ensured that the protrusion 3 has sufficient structural strength to withstand the impact of the electrolyte, thus achieving a buffering effect. If the wall thickness T of the protrusion 3 is less than 0.4mm, the protrusion 3 is easily damaged by the impact of the electrolyte; if the wall thickness T of the protrusion 3 is greater than 1.5mm, it will shrink and deform during injection molding and occupy more space.

[0059] Furthermore, in one embodiment, the wall thickness T of the protrusion 3 satisfies 0.5mm≤T≤1mm.

[0060] The working principle of this utility model embodiment is as follows:

[0061] The electrolyte first enters the containment space formed by the protrusion 3 and the cover plate 2 through the injection hole 201. After being buffered by the bottom platform of the protrusion 3, the electrolyte flows along the inclined bottom surface of the protrusion 3 to multiple through holes 301, and then flows evenly into the cell through multiple through holes 301.

[0062] According to an embodiment of this utility model, another aspect provides a battery cell, mainly comprising: a housing, a cover plate 2, and a lower plastic core. An opening is provided on one side of the housing. The cover plate 2 covers the opening and has an injection hole 201. The plastic body 1 of the lower plastic core is disposed inside the cover plate 2, and the protrusion 3 of the plastic body 1 is correspondingly provided with the injection hole 201.

[0063] Because the battery cell includes a lower plastic body, it has the same effect as the lower plastic body. Specifically, the lower plastic body 1 has a protrusion 3 that blocks the injection hole 201. When electrolyte is added to the battery cell through the injection hole 201, the protrusion 3 buffers the impact of the electrolyte after it passes through the injection hole 201. After buffering, the electrolyte flows into the battery cell through the through hole 301 on the protrusion 3. This effectively prevents the electrolyte from directly impacting the electrode assembly inside the battery cell, avoiding damage to the electrode assembly, ensuring injection stability, thereby improving the safety and reliability of the battery cell. It also helps reduce the risk of leakage from the injection hole 201 and lowers usage costs. Furthermore, the protrusion 3 is located on the side of the plastic body 1 away from the cover plate 2, so it does not affect the connection between the plastic body 1 and the cover plate 2, facilitating battery cell assembly.

[0064] Specifically, the housing also includes an electrode assembly, with a lower plastic layer positioned between the electrode assembly and the cover plate 2 for insulation. For example... Figure 1 and Figure 2As shown, a pair of electrode posts are spaced apart on the side of the electrode assembly near the cover plate 2. The pair of electrode posts includes a positive electrode post 4 and a negative electrode post 5. Correspondingly, the lower plastic part has positive and negative electrode post mounting holes. The positive electrode post 4 passes through the positive electrode post mounting hole and is mounted on the cover plate 2, and the negative electrode post 5 passes through the negative electrode post mounting hole and is mounted on the cover plate 2. The cover plate 2 also has an explosion-proof valve 6, with an injection hole 201 located between the explosion-proof valve 6 and the electrode post. Correspondingly, a protrusion 3 is installed between the electrode post mounting hole and the explosion-proof valve 6. The lower plastic part also has a vent hole corresponding to the explosion-proof valve 6.

[0065] Since the position of the lower plastic part corresponding to the pole needs to leave space for the installation of the support structure, and the position of the lower plastic part corresponding to the explosion-proof valve 6 needs to leave a venting channel, the protrusion 3 is installed between the pole mounting hole and the explosion-proof valve 6, which will not take up too much space inside the cell.

[0066] Furthermore, the opposite ends of the plastic body 1 extend inwards to install the electrode post and the explosion-proof valve 6. A groove is formed in the middle area of ​​the inner side of the lower plastic body, and the protrusion 3 is located in this groove. The lowest surface of the protrusion 3 does not exceed the lowest surface of the plastic body 1 to avoid the protrusion 3 compressing the electrode assembly. Here, the lowest surface refers to the inner surface of the plastic body 1. For example, if the lowest surface of the plastic body 1 is the end where the explosion-proof valve 6 is installed, then the lowest surface of the protrusion 3 is as follows: Figure 7 As shown by arrow M, the lowest surface of the plastic is as follows: Figure 7 As indicated by arrow N. Of course, in other embodiments, the lowest surface of the plastic body 1 can also be the end where the pole is mounted.

[0067] According to an embodiment of the present invention, in another aspect, a battery pack is also provided, comprising: at least one of the above-described battery cells.

[0068] The battery pack provided in this embodiment of the utility model has a protrusion 3 on the plastic body 1 of the lower plastic portion that blocks the electrolyte injection hole 201. When electrolyte is added to the cell through the electrolyte injection hole 201, the protrusion 3 buffers the impact of the electrolyte after it passes through the injection hole 201. After buffering, the electrolyte flows into the cell through the through hole 301 on the protrusion 3. This effectively prevents the electrolyte from directly impacting the electrode assembly inside the cell, avoiding damage to the electrode assembly, ensuring the stability of the electrolyte injection, thereby improving the safety and reliability of the cell. It also helps to reduce the risk of leakage from the electrolyte injection hole 201 and reduce the cost of use. Moreover, the protrusion 3 is located on the side of the plastic body 1 away from the cover plate 2, so it does not affect the connection between the plastic body 1 and the cover plate 2, which facilitates the assembly of the cell.

[0069] To achieve the basic functions of the battery pack, the battery pack in this embodiment may also include other necessary modules or components, such as a battery management system and a heat dissipation system. It should be noted that any suitable existing structure can be selected from the other necessary modules or components included in the battery pack. To clearly and concisely illustrate the technical solution provided in this embodiment, the above-mentioned parts will not be repeated here, and the accompanying drawings have also been simplified accordingly. However, it should be understood that the scope of the embodiments of this utility model is not limited thereto.

[0070] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A type of plastic, characterized in that, include: A plastic body is adapted to be connected to a cover plate of a battery cell. The cover plate has an injection hole. The portion of the plastic body corresponding to the injection hole extends away from the cover plate to form a protrusion. The protrusion has at least one through hole on the side opposite to the injection hole, and the through hole communicates with the injection hole.

2. The lower plastic according to claim 1, characterized in that, The protrusion with the through hole is inclined downwards towards the plastic body.

3. The lower plastic according to claim 2, characterized in that, The protruding part has a cone-shaped section on one side of the through hole that protrudes toward the injection hole.

4. The lower plastic according to claim 3, characterized in that, The inclination angle θ between the side of the protrusion with the through hole and the sidewall of the protrusion satisfies 5°≤θ<90°.

5. The lower plastic according to claim 2, characterized in that, When multiple through holes are provided, the multiple through holes are circumferentially spaced on the side of the protrusion opposite to the injection hole.

6. The lower plastic according to claim 5, characterized in that, The total area of ​​the openings of the plurality of through holes is greater than or equal to the opening area of ​​the injection hole.

7. The lower plastic according to any one of claims 1 to 6, characterized in that, The height H of the protrusion satisfies 2mm < H ≤ 10mm.

8. The lower plastic according to any one of claims 1 to 6, characterized in that, The wall thickness T of the protrusion satisfies 0.4mm < T ≤ 1.5mm.

9. A battery cell, characterized in that, include: The casing has an opening on one side; A cover plate is placed over the opening and has an injection hole; The lower plastic according to any one of claims 1 to 8, wherein the plastic body is disposed inside the cover plate, and the protrusion of the plastic body is correspondingly disposed to the injection hole.

10. A battery pack, characterized in that, include: At least one battery cell as described in claim 9.

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