Battery pack and connecting screw thereof

Abstract

This utility model discloses a connecting screw, including a screw head and a screw body connected together. The screw body includes a threaded section and a tapping section. The tapping section is located at the end of the screw body away from the screw head, and the threaded section is located at the position of the screw body close to the screw head. The threaded section includes a first sub-threaded section and a second sub-threaded section connected together. The first sub-threaded section is located close to the screw head, and a sealant layer is provided on the first sub-threaded section to form a sealing section. The length L1 of the threaded section and the length L2 of the sealing section satisfy the formula 0.02≤(L2×K) / L1≤0.25, where K is the friction coefficient of the sealant layer of the sealing section. The connecting screw of this utility model improves the sealing performance of the connection position, reduces the possibility of foreign objects entering the battery pack through the screw connection position, and reduces the probability of thermal runaway of the battery pack caused by foreign objects entering the battery pack. This utility model also discloses a battery pack.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery pack and its connecting screw. Background Technology

[0002] Battery packs, as energy storage devices, are increasingly widely used in daily life and industry. A battery pack includes a housing, which comprises a base plate and a frame. The base plate and frame are typically connected together by screws, and the sealing performance of these screws has a significant impact on the reliability of the battery pack's sealing.

[0003] In existing technologies, the connection between the base plate and the frame is achieved by first drilling connection holes in the base plate and then connecting the screws into the connection holes. However, the sealing performance of the screw connection location is difficult to meet standards, making it easy for external moisture or foreign objects to enter the battery pack through the screw connection location, causing the battery pack seal to fail. The entry of foreign objects or moisture into the battery pack can easily lead to thermal runaway. Therefore, how to provide a screw with good sealing performance has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] In view of this, the present invention provides a connecting screw that improves the sealing performance of the connection position, reduces the possibility of foreign objects entering the battery pack through the connection position of the screw, and reduces the probability of thermal runaway of the battery pack caused by foreign objects entering the battery pack.

[0005] This utility model also provides a battery pack.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A connecting screw includes a head and a body connected together. The head includes a threaded section and a tapping section. The tapping section is located at the end of the head away from the head, and the threaded section is located at the head near the head. The threaded section includes a first sub-threaded section and a second sub-threaded section connected together. The first sub-threaded section is located near the head, and a sealant layer is provided on the first sub-threaded section to form a sealing section. The length L1 of the threaded section and the length L2 of the sealing section satisfy the formula 0.02≤(L2×K) / L1≤0.25, where K is the coefficient of friction of the sealant layer of the sealing section.

[0008] As can be seen from the above technical solution, the connecting screw provided by this utility model improves the sealing performance of the connection position by setting the first threaded section of the connecting screw as a sealing section with a sealing layer. When the connected parts are connected, the sealing section seals the threaded connection through the structure of the thread and the sealing layer on the thread. Simultaneously, it is necessary to ensure that the ratio of (L2×K) / L1 is within a set range to guarantee sealing performance while reducing the resistance during drilling the connecting screw. The connecting screw of this utility model improves the sealing performance of the connection position, reduces the risk of seal failure, and improves the situation where external moisture or other foreign objects enter the battery pack through the screw connection position, reducing the probability of thermal runaway of the battery pack caused by foreign objects entering the battery pack.

[0009] This utility model also provides a battery pack, including a housing and a battery placed inside the housing. The housing includes a frame and a bottom plate, which are connected by screws, namely the connecting screws described above.

[0010] The battery pack of this utility model includes the aforementioned connecting screw, and therefore has the advantages of the aforementioned connecting screw, which will not be elaborated here. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A schematic diagram of the structure of a connecting screw at one angle provided in an embodiment of this utility model;

[0013] Figure 2 This is a structural schematic diagram of the connecting screw from another angle provided in an embodiment of the present invention;

[0014] Figure 3 A structural schematic diagram of the connecting screw at the third angle provided in an embodiment of this utility model;

[0015] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure at position AA in the middle;

[0016] Figure 5 This is a schematic diagram of the connection structure between the frame and the base plate provided in an embodiment of the present utility model;

[0017] Figure 6A cross-sectional view of the connection points between the frame and the base plate via connecting screws, provided for an embodiment of this utility model.

[0018] Figure 7 A partial cross-sectional view of the positions of the first and second connecting holes provided for an embodiment of the present utility model;

[0019] Figure 8 An enlarged cross-sectional view of the connection points between the frame and the base plate via connecting screws, provided for an embodiment of this utility model.

[0020] Figure 9 A schematic diagram of the connection structure between the frame and the base plate provided in another embodiment of this utility model.

[0021] in:

[0022] 100. Connecting screws; 200. Frame; 300. Base plate.

[0023] 1. Nail head,

[0024] 101. Annular cavity; 102. Mounting slot.

[0025] 2. Nail body,

[0026] 201. Attack Section

[0027] 2011, Penetrating the tip segment; 2012, Penetrating the body segment; 2013, Cylindrical segment; 2014, Connecting the dividing line.

[0028] 202. Threaded section

[0029] 2021, First threaded section; 2022, Second threaded section.

[0030] 3. First connecting hole,

[0031] 4. Second connecting hole,

[0032] 5. First annular boss,

[0033] 6. Second annular boss. Detailed Implementation

[0034] This utility model discloses a connecting screw that improves the sealing performance of the connection position, reduces the possibility of foreign objects entering the battery pack through the connection position of the screw, and lowers the probability of thermal runaway of the battery pack caused by foreign objects entering the battery pack.

[0035] This utility model also discloses a battery pack.

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] See Figures 1 to 4 The connecting screw 100 of this utility model includes a screw head 1 and a screw body 2 connected together. The screw body 2 includes a threaded section 202 and a tapping section 201. The tapping section 201 is located at the end of the screw body 2 away from the screw head 1, and the threaded section 202 is located at the position of the screw body 2 close to the screw head 1. The threaded section 202 includes a first sub-threaded section 2021 and a second sub-threaded section 2022 connected together. The first sub-threaded section 2021 is located close to the screw head 1, and the second sub-threaded section 2022 is located away from the screw head 1. The first sub-threaded section 2021 and the second sub-threaded section 2022 extend along the screw body 2. A sealant layer is provided on the first sub-threaded section 2021 to form a sealing section. The sealing section is used to connect a connected component, which may be the casing of a battery pack. The length L1 of the threaded section 202 and the length L2 of the sealing section satisfy the formula 0.02≤(L2×K) / L1≤0.25, where K is the coefficient of friction of the sealant layer of the sealing section. The sealant layer can be applied to the first threaded section 2021 or filled into the thread of the first threaded section 2021. The value of the formula (L2×K) / L1 can be any one of 0.02, 0.09, 0.15, 0.25, or a value between any two of these.

[0038] To improve the sealing performance of the connection, the connecting screw 100 is a flow drill screw (FDS). The flow drill screw forms a threaded hole by cutting the connected parts through rotational motion, eliminating the need for pre-drilling and thus improving production efficiency. A larger sealing section length L2 means more threads with a sealing layer when the connecting screw 100 is connected, resulting in better sealing performance at the threaded connection. A higher coefficient of friction K for the sealing layer makes it less prone to detachment and more adhesive to the threads, allowing the threads of the connecting screw 100 to better bond with the connected parts, significantly improving the sealing performance of the threaded connection. Conversely, if the length L2 of the sealing section remains constant, a larger threaded section length L1 results in a smaller proportion of the sealing section length L2 to the total length of the threaded section 202. In this case, the sealing performance of the connecting screw 100 at the connection position deteriorates. Since, when parameter L1 remains constant, increasing parameters L2 and K both positively improve the sealing performance of the screw connection, while increasing L1 while keeping L2 and K constant negatively impacts the sealing performance, parameters L2 and K are positioned in the numerator and denominator of the above formula, respectively. A larger ratio in the formula indicates better sealing performance at the screw connection; otherwise, the sealing performance is poor.

[0039] The connecting screw 100 of this utility model improves the sealing performance of the connection location by setting the first threaded section 2021 on the connecting screw 100 as a sealing section with a sealing layer. When connecting the connected parts, the sealing section seals the threaded connection through the structure of the thread and the sealing layer on the thread, thus improving the sealing performance of the connection location. At the same time, it is necessary to ensure that the ratio of (L2×K) / L1 is within a set range to ensure the sealing performance while reducing the resistance when drilling the connecting screw 100. The connecting screw 100 of this utility model improves the sealing performance of the connection location, reduces the risk of seal failure, and improves the situation where external moisture or other foreign objects enter the battery pack through the screw connection location, thus reducing the probability of thermal runaway of the battery pack caused by foreign objects entering the battery pack.

[0040] Specifically, the length L1 of the threaded segment 202 is in the range of 8mm ≤ L1 ≤ 20mm, and can be any value among 8mm, 15mm, 20mm, etc., or a value between any two values. If the length L1 of the threaded segment 202 is too small, the length of the second threaded segment 2022 used for chip drilling is limited, making chip drilling difficult, and it will also affect the length of the first threaded segment 2021, thus affecting the length of the sealing segment, resulting in insufficient connection strength and sealing performance. If the length L1 of the threaded segment 202 is too large, the drilling length of the connecting screw 100 during flow drilling is large, and the flow drilling time is long. Due to the effect of heat melting on the thread during flow drilling, the sealing performance of the threaded connection position will be affected. Therefore, the length range of parameter L1 is limited to ensure both sealing performance and connection strength. The length L2 of the sealing segment is in the range of 3mm ≤ L2 ≤ 10mm, and can be any value among 3mm, 7mm, 10mm, etc., or a value between any two values. When the length L2 of the sealing section is too small, the sealing effect at the connection point is poor. When the length L2 is too large, the resistance is high when the connecting screw 100 self-drills. Therefore, the length range of parameter L2 is limited to ensure the screw's sealing performance while reducing the resistance during self-drilling. The friction coefficient K of the sealing layer is in the range of 0.1≤K≤0.25, specifically any value among 0.1, 0.15, and 0.25, or a value between any two values. When the friction coefficient K of the sealing layer is too large, although the sealing layer is not easy to fall off and can ensure the sealing requirement, excess adhesive is not easily carried away by the thread self-drilling, which may lead to insufficient thread depth at the connection point between the first thread segment 2021 and the connected part, affecting the connection strength. When the friction coefficient K of the sealing layer is too small, the sealing layer is easy to fall off during screw self-drilling, affecting the sealing performance. Therefore, the range of the friction coefficient K of the sealing layer is limited to ensure both connection strength and sealing performance.

[0041] To ensure reliable connection, the threaded section 202 extends from the position of the nail head 1 to the insertion section 201, that is, the threaded section 202 is located between the nail head 1 and the insertion section 201, and the threaded section 202 is located at the position of the nail body 2 excluding the insertion section 201.

[0042] In one embodiment, the starting end of the sealing segment contacts the end face of the nail head 1. In this embodiment, the sealing segment is set starting from the end face of the nail head 1. In another embodiment, the threaded segment 202 further includes a third sub-threaded segment (not shown in the figure). The third sub-threaded segment, the first sub-threaded segment 2021, and the second sub-threaded segment 2022 extend sequentially from the nail head 1 towards the insertion segment 201. The third sub-threaded segment is disposed between the sealing segment and the nail head 1. In this embodiment, the first sub-threaded segment 2021 is spaced from the nail head 1 by the third sub-threaded segment.

[0043] Furthermore, the ratio of the length L2 of the sealing section to the length L1 of the threaded section 202 is in the range of 0.2 ≤ L2 / L1 ≤ 0.8. Specifically, the ratio of L2 / L1 can be any value among 0.2, 0.5, 0.8, or a value between any two values. Limiting the ratio of parameters L2 and L1 to the above range avoids excessive resistance when the connecting screw 100 self-drills a hole if the ratio of L2 and L1 is too large, and also prevents the sealing performance of the threaded connection from being affected if the ratio of L2 and L1 is too small.

[0044] To ensure both the self-drilling performance of the connecting screw 100 and the sealing performance of the threaded connection, the length of the screw body 2 is L3. The ratio of the length of the sealing section L2 to the length of the screw body 2 L3 is in the range of 0.15 ≤ L2 / L3 ≤ 0.5. Specifically, the ratio of L2 / L3 can be any value among 0.15, 0.3, 0.5, or any value between any two. If the ratio of L2 to L3 is too small, the screw's connection sealing performance is poor; if the ratio of L2 to L3 is too large, the self-drilling resistance of the connecting screw 100 is high, resulting in poor self-drilling performance.

[0045] In one specific embodiment, the pitch of the first threaded segment 2021 ranges from 0.6 to 1.2 mm, specifically any value among 0.6 mm, 0.8 mm, and 1.2 mm, or a value between any two values. By setting the pitch range of the first threaded segment 2021 within the above range, excessively large pitches are avoided from affecting the tensile strength and sealing performance of the first threaded segment 2021, while excessively small pitches are avoided from increasing the processing difficulty of the thread, shortening the connection time, and improving the connection efficiency. The thread depth of the first threaded segment 2021 ranges from 0.5 to 1.5 mm, specifically any value among 0.5 mm, 1 mm, and 1.5 mm, or a value between any two values. By setting the thread depth of the first threaded segment 2021 within the above range, both the accommodation space of the sealing adhesive layer of the sealing segment and the strength of the connecting screw 100 can be guaranteed.

[0046] To improve self-drilling performance, the penetration section 201 includes a penetration tip section 2011 and a penetration body section 2012, such as... Figure 2 and Figure 4As shown, the outer surface of the tapping tip 2011 is a first conical surface, and the tapping body section 2012 is provided with a second conical surface near the tapping tip 2011. The cone angle of the first conical surface is smaller than that of the second conical surface, so as to form a connecting boundary line 2014 at the connection position of the tapping tip 2011 and the tapping body section 2012. This allows the tapping section 201 to form two conical surfaces with different cone angles, so as to achieve constant force drilling and hole enlargement of the connecting screw 100 and avoid the need to increase the drilling force when the tapping section 201 has only one conical surface. The end of the tapping body section 2012 away from the tapping tip 2011 is connected to the threaded section 202 through the cylindrical section 2013.

[0047] The connecting screw 100 of this invention improves the sealing performance of the connection position of the connected components by providing a sealing section with a sealing adhesive layer on the connecting screw 100. The connecting screw 100 of this invention improves the sealing performance of the connection position, reduces the risk of seal failure, improves the sealing performance of the battery pack, and reduces the probability of thermal runaway of the battery pack caused by foreign objects entering the battery pack.

[0048] This utility model also provides a battery pack, including a housing and a battery placed inside the housing. The housing includes a frame 200 and a base plate 300, as shown below. Figures 5 to 9 As shown, the frame 200 and the base plate 300 are connected by screws, specifically the connecting screws 100 described above. The frame 200 and the base plate 300 are the connected components. Because the connecting screws 100 provide good sealing, using them to connect the frame 200 and the base plate 300 results in better sealing at the connection point. This reduces the probability of moisture, dust, and other foreign matter entering the cavity formed by the frame 200 and the base plate 300 through the connection point of the connecting screws 100, thus improving the safety performance of the battery placed within the cavity.

[0049] To facilitate the connection of the connecting screws 100, a first connecting hole 3 is provided on the base plate 300, and a second connecting hole 4 is provided on the frame 200. Figure 7As shown, both the first connecting hole 3 and the second connecting hole 4 are drilled out by the connecting screw 100 during connection, and the threaded section 202 of the connecting screw 100 is connected within the first connecting hole 3 and the second connecting hole 4. In one embodiment, to improve the sealing performance at the connection position of the threaded section 202, the sealing section of the connecting screw 100 is connected at the position of the first connecting hole 3 and the second connecting hole 4, that is, the first branch threaded section 2021 is connected at the position of the first connecting hole 3 and the second connecting hole 4, and the sum of the hole heights of the first connecting hole 3 and the second connecting hole 4 is less than or equal to the thread length of the first branch threaded section 2021, so that the thread with the sealant layer is connected within the first connecting hole 3 and the second connecting hole 4. In other embodiments, the sealing section of the connecting screw 100 is connected at least in all or part of the position of the first connecting hole 3 or the second connecting hole 4.

[0050] To prevent dust or moisture from entering the first connecting hole 3 on the base plate 300, the end face of the connecting screw 100 near the screw body 2 abuts against the base plate 300, such as... Figure 5 and Figure 6 As shown, the end face of the nail head 1 near the nail body 2 is pressed tightly against the surface of the base plate 300, reducing the risk of foreign objects entering the first connecting hole 3 through the gap between the base plate 300 and the end face of the nail head 1. In one embodiment, the base plate 300 is a bottom cold plate, which includes a first cold plate and a second cold plate connected together, such as... Figures 5 to 8 As shown, the first and second cold plates form a cooling cavity. Figure 9 As shown, the base plate 300 is a single-layer plate.

[0051] Furthermore, the end face of the nail head 1 near the nail body 2 is provided with an annular cavity 101, such as... Figure 1 and Figure 4 As shown, the annular cavity 101 is arranged around the end of the nail body 2 near the nail head 1, that is, the annular cavity 101 is located at the root of the nail body 2 and is arranged around the root of the nail body 2. Correspondingly, a first annular boss 5 is provided on the base plate 300. The first annular boss 5 is arranged around the end of the first connecting hole 3 away from the frame 200. The first annular boss 5 is correspondingly arranged with the annular cavity 101. Here, "correspondingly arranged" means that the positions are correspondingly arranged. The first annular boss 5 is located inside the annular cavity 101, as shown. Figure 8 As shown, the first annular boss 5 extends into the annular cavity 101, forming a sealing structure on the end face of the nail head 1 near the base plate 300, further improving the sealing performance at this location. The radial thickness of the first annular boss 5 is less than the radial dimension of the annular cavity 101, so that the first annular boss 5 can extend into the annular cavity 101. A mounting groove 102 is provided on the end face of the nail head 1 away from the nail body 2. The groove shape of the mounting groove 102 corresponds to the tool used when drilling the hole for the connecting screw 100, such as... Figure 3This is a schematic diagram of one type of slot for mounting slot 102. In other embodiments, it can also be other types of slots used in conjunction with tools, which are not limited here.

[0052] The height of the first annular boss 5 is less than or equal to the depth of the annular cavity 101. This structural arrangement ensures that the end face of the annular cavity 101 of the nail head 1 can be pressed against the end face of the base plate 300, thereby further ensuring the sealing of the contact position between the end face of the nail head 1 and the base plate 300.

[0053] In one embodiment, the thread of the sealing section of the connecting screw 100 is at least partially connected to the position of the first annular boss 5, so as to form a seal between the first annular boss 5 and the threaded connection.

[0054] To achieve a better seal on the end of the second connecting hole 4 away from the first connecting hole 3, a second annular boss 6 is provided on the frame 200. The second annular boss 6 is positioned around the end of the second connecting hole 4 away from the base plate 300. The thread of the sealing section of the connecting screw 100 is at least partially engaged with the second annular boss 6 to form a seal between the second annular boss 6 and the threaded connection.

[0055] To facilitate the connection between the base plate 300 and the frame 200, the frame 200 is configured as a hollow plate with a cavity, such as... Figure 6 As shown. At the same time, the frame 200 is set as a cavity plate with a cavity, which can reduce the weight of the box, provide good heat and sound insulation performance, and reduce the impact of the external temperature on the battery.

[0056] The battery pack of this utility model has its frame 200 and base plate 300 connected by connecting screws 100, which provides good sealing and effectively reduces the entry of foreign objects into the battery pack, thus effectively protecting the batteries inside the pack.

[0057] In the description of this solution, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this solution, "multiple" means two or more, unless otherwise explicitly specified.

[0058] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A connecting screw, comprising a screw head and a screw body connected together, characterized in that, The nail body includes a threaded section and a tapping section, the tapping section being located at the end of the nail body away from the nail head, and the threaded section being located at the position of the nail body close to the nail head; The threaded section includes a first threaded section and a second threaded section connected together. The first threaded section is located close to the nail head. A sealant layer is provided on the first threaded section to form a sealing section. The length L1 of the threaded section and the length L2 of the sealing section satisfy the formula 0.02≤(L2×K) / L1≤0.25, where K is the friction coefficient of the sealant layer of the sealing section.

2. The connecting screw according to claim 1, characterized in that, The length L1 of the threaded section is in the range of 8mm≤L1≤20mm, the length L2 of the sealing section is in the range of 3mm≤L2≤10mm, and the friction coefficient K of the sealing adhesive layer is in the range of 0.1≤K≤0.

25.

3. The connecting screw according to claim 1, characterized in that, The threaded section extends from the nut to the insertion section.

4. The connecting screw according to any one of claims 1-3, characterized in that, One end of the sealing section contacts the end face of the nail head.

5. The connecting screw according to any one of claims 1-3, characterized in that, The threaded section also includes a third sub-threaded section. The third sub-threaded section, the first sub-threaded section, and the second sub-threaded section extend sequentially from the nail head to the insertion section. The third sub-threaded section is disposed between the sealing section and the nail head.

6. The connecting screw according to claim 1, characterized in that, The length L2 of the sealing section and the length L1 of the threaded section satisfy 0.2≤L2 / L1≤0.

8.

7. The connecting screw according to claim 1, characterized in that, The length of the nail body is L3, and the length of the sealing section L2 and the length of the nail body L3 satisfy 0.15≤L2 / L3≤0.

5.

8. The connecting screw according to claim 1, characterized in that, The pitch range of the first threaded section is 0.6-1.2mm, and the thread depth range of the first threaded section is 0.5-1.5mm.

9. The connecting screw according to claim 1, characterized in that, The penetration section includes a penetration tip and a penetration body. The outer surface of the penetration tip is a first conical surface, and the penetration body is provided with a second conical surface near the penetration tip. The cone angle of the first conical surface is smaller than the cone angle of the second conical surface.

10. A battery pack, comprising a housing and a battery disposed within the housing, the housing comprising a frame and a bottom plate, characterized in that, The frame and the base plate are connected by screws, wherein the screws are the connecting screws as described in any one of claims 1-9.

11. The battery pack according to claim 10, characterized in that, The base plate is provided with a first connecting hole drilled by the connecting screw, and the frame is provided with a second connecting hole drilled by the connecting screw. The sealing section of the connecting screw is connected to the first connecting hole and / or the second connecting hole.

12. The battery pack according to claim 11, characterized in that, The head of the connecting screw abuts against the base plate near the end face of the screw body.

13. The battery pack according to claim 12, characterized in that, The nail head has an annular cavity on its end face near the nail body, and the annular cavity is arranged around the end of the nail body near the nail head; The base plate is provided with a first annular boss, which is provided around the end of the first connecting hole away from the frame. The first annular boss is provided corresponding to the annular cavity, and the first annular boss is provided in the annular cavity.

14. The battery pack according to claim 13, characterized in that, The height of the first annular boss is less than or equal to the depth of the annular cavity.

15. The battery pack according to claim 13, characterized in that, The thread of the sealing section of the connecting screw is at least partially connected to the first annular boss.

16. The battery pack according to claim 11, characterized in that, A second annular protrusion is provided on the frame, and the second annular protrusion is provided around the end of the second connecting hole away from the base plate.

17. The battery pack according to claim 16, characterized in that, The thread of the sealing section of the connecting screw is at least partially connected to the second annular boss.

18. The battery pack according to claim 10, characterized in that, The frame is a hollow plate with a cavity.

Images