Injection molded cover plate assembly and battery

Abstract

The application relates to an injection-molded cover plate assembly and a battery, comprising a cover plate body and a pole, a pole body part of the pole is coaxially arranged in a pole hole of the cover plate body, a protruding part is arranged on the cover plate body and takes the pole hole as a center, and an upper plastic part is filled between the pole body part and the protruding part and surrounds the protruding part. The application further regulates and controls the coupling design relationship of multiple parameters between the protruding part and the pole. The application can effectively solve the mutual restraint problems among mechanical interlocking, air tightness maintenance, insulation guarantee and heat management, and greatly improves the comprehensive performance and safety margin of the battery cover plate under complex working conditions.

Description

Technical Field

[0001] This invention belongs to the field of battery structure technology, specifically relating to an injection-molded cover plate assembly and a battery. Background Technology

[0002] In the field of lithium-ion battery manufacturing, the cover plate assembly serves as a crucial barrier isolating the internal battery cells from the external environment, and its structural strength and airtightness directly determine the battery's safety performance. Injection-molded integrated cover plates, by combining the cover plate body and the terminals through plastic injection molding, utilize the sealing properties of the plastic parts to achieve insulation and sealing between the terminals and the cover plate, and have become the mainstream choice for high-energy-density batteries.

[0003] In existing processes, the cover plate body is typically used as an insert in injection molding, with a smooth surface or only simple positioning holes. However, as batteries move towards higher voltages (such as the 800V platform) and thinner designs, the bonding force between the smooth cover plate body and the plastic part often struggles to withstand shear stress under complex operating conditions. The industry has attempted to add knurling or grooves to the surface of the terminal posts to enhance the interfacial mechanical interlocking between the terminal posts and the plastic part. Similar structural reinforcement methods have also been applied to the cover plate body, increasing the contact area and mechanical interlocking force between the plastic part and the cover plate body by introducing uneven structures on the cover plate surface. However, the smooth, large-area, thin-layer cover plate body and the terminal post structure have significant intrinsic differences. The uneven structure faces a multi-field coupling environment of force, gas, heat, and electricity on the cover plate body, which in turn leads to more new technical challenges.

[0004] First, there is the risk of seal failure caused by force-gas coupling. The cover plate body is usually thin, and forming an uneven structure on it inevitably involves local material stretching and thinning. When the terminal post is subjected to assembly torsional force or thermal stress due to the difference in thermal expansion coefficient, the stress will be transmitted to the uneven joint surface around the terminal post hole of the cover plate body. Due to the reduced strength of the thinned area, plastic deformation or even microcracks are very likely to occur, resulting in a sharp decrease in the interfacial bonding force between the cover plate and the plastic part. Consequently, under the "wedge effect" of high-pressure gas inside the battery, airtightness failure will occur.

[0005] Secondly, there are potential risks of insulation and leakage current caused by electrothermal coupling. The cover plate itself carries an extremely high potential difference (relative to the inside of the battery cell). Adding uneven structures to the cover plate, if not designed properly, can easily lead to localized electric field concentration. At the same time, the structural changes brought about by the uneven structures, especially sharp changes, can easily become channels for electrolyte penetration if the injection molding is not properly covered. This shortened creepage distance caused by structural defects will significantly increase the risk of leakage current and may even lead to breakdown and short circuit.

[0006] Third, the difficulty of thermal management increases significantly. The cover plate is one of the important pathways for battery heat dissipation. The irregular surface processing of the cover plate alters the local heat dissipation area and heat capacity distribution. In environments such as laser welding of the tabs or high-temperature injection molding, heat accumulation easily forms at the irregular structures, leading to excessively high local temperatures. This can not only cause carbonization of the plastic parts but also exacerbate the thermal mismatch between the metal cover plate and the plastic parts, further deteriorating the interfacial bonding.

[0007] Therefore, how to design the interface bonding structure between the cover plate body and the plastic parts so that the plastic parts / cover plate body can enhance mechanical interlocking without compromising the mechanical integrity, insulation reliability and thermal management capability of the cover plate is a technical bottleneck that urgently needs to be overcome in this field.

[0008] Therefore, this application is submitted. Summary of the Invention

[0009] This invention addresses the problems in existing injection-molded cover designs by providing an injection-molded cover assembly and battery that effectively solves the mutual constraints between mechanical interlocking, airtightness maintenance, insulation protection, and thermal management, significantly improving the overall performance and safety margin of the battery cover under complex operating conditions.

[0010] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0011] The present invention first proposes an injection-molded cover plate assembly, comprising a cover plate body and an electrode post;

[0012] The pole includes a plate part and a column part. The column part is coaxially inserted into the pole hole opened along the Z direction on the cover plate body. The plate part connected to the column part is located below the cover plate body along the Z direction.

[0013] On the cover plate body, there is a protrusion that is upward along the Z direction with the pole hole as the center. The protrusion includes a top protrusion area and a bottom support area. The radial spacing of the protrusion area is greater than that of the support area. The protrusion area and the support area are connected by a transition area with a gradually changing radial spacing.

[0014] An upper plastic part is provided on the outer periphery of the column part. The upper plastic part fills the gap between the column part and the protrusion above the plate part and surrounds the protrusion above the cover plate body.

[0015] The thickness T of the cover plate body is 1.5~3mm, the protrusion height H of the protrusion on the cover plate body is (0.8~1.2)×T, the distance h between the protruding head area of ​​the protrusion and the cover plate body is (0.3~0.6)×H, the wall thickness t of the protrusion is (0.3~0.8)×T, the radial distance t1 of the support area of ​​the protrusion is (0.5~1.2)×T, the radial distance A between the outer wall surface of the protruding head area and the support area is (0.2~0.5)×H, the shortest distance B1 between the protruding head area of ​​the protrusion and the column part of the pole is 0.8~1.5mm, the thickness B2 of the upper plastic part surrounding the top of the protrusion is 0.5~1.2mm, and the minimum thickness B3 of the upper plastic part surrounding the outer periphery of the protrusion is 0.5~1.2mm.

[0016] In another aspect, the present invention provides a battery, including a housing and the aforementioned injection-molded cover assembly, wherein the housing and the aforementioned injection-molded cover assembly together enclose a cavity for accommodating a battery cell, and the electrode plates of the battery cell are connected to the terminals on the injection-molded cover assembly according to the polarity of the positive and negative terminals.

[0017] Compared with the prior art, the injection-molded cover plate assembly and battery of the present invention optimize the structural connection between the cover plate body and the upper plastic part of the electrode by specially setting a protrusion in the area around the electrode hole, and with the help of precise dimensional control, achieve synergistic optimization of force-air-heat-electric multiple fields, and have the following significant beneficial effects:

[0018] (1) Mechanical properties

[0019] The protrusion provides a reinforcing effect with high shear strength, which can evenly distribute and transfer the torsional torque generated during assembly and the vibration load during battery operation to the cover plate body, effectively avoiding stress concentration at the edge of the terminal hole. Compared with traditional flat or simple embossed cover plates, this invention greatly improves the shear threshold of the junction between the terminal and the terminal hole under complex mechanical conditions.

[0020] (2) Maintaining airtightness

[0021] The protrusions create a highly rigid mechanical interlocking system between the upper plastic component and the cover plate body after injection molding, significantly suppressing fretting displacement at the interface between the cover plate body and the upper plastic component under alternating loads. This highly conformal interface bonding not only helps eliminate gas permeation channels caused by interface gaps but also effectively resists the "wedge effect" of high-pressure gas inside the battery on the bonding surface. This improves the structure's ability to maintain excellent interface sealing integrity under long-term extreme environments (high temperature and humidity or thermal cycling environments, etc.), ensuring helium testing pass rate and long-term airtightness.

[0022] (3) Insulation protection

[0023] The cover plate body is prone to electric field concentration. The controlled surrounding structure of the protrusion and the upper plastic part significantly reduces the local electric field strength, preventing partial discharge caused by electric field distortion. At the same time, it ensures the minimum effective thickness of the upper plastic part, improves the creepage distance and electrical insulation strength, and effectively reduces the risk of leakage current.

[0024] (4) Thermal management

[0025] While increasing structural strength, the protrusions maintain the uniformity of the overall heat capacity of the cover plate body and the reasonable positional relationship with the pole. This is conducive to the uniform dissipation of heat during the injection molding process and subsequent laser welding process, avoiding plastic carbonization or thermal aging caused by local overheating. In addition, it is also conducive to forming an optimized heat conduction path with the pole, alleviating the thermal stress caused by the difference in thermal expansion coefficients between the cover plate body and the polymer plastic parts, and improving the thermal dimensional stability of the injection molded cover plate assembly.

[0026] (5) Multi-dimensional balance of fine size control

[0027] By finely controlling the key geometric parameters between the protrusion and the upper plastic part, the intrinsic relationship between the above-mentioned mechanical properties, airtightness, insulation protection and thermal management characteristics was established. This avoids the phenomenon of sacrificing other properties due to the improvement of a single performance index, thereby achieving a precise balance and synergistic gain of the above-mentioned multi-dimensional performance at the microscale. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a perspective view of a specific embodiment of the injection-molded cover plate assembly of the present invention.

[0030] Figure 2 for Figure 1 Structural diagram in the XZ plane.

[0031] Figure 3 for Figure 1 Structural diagram in the XY plane.

[0032] Figure 4 for Figure 3 Cross-sectional view along the AA direction.

[0033] Figure 5 for Figure 4 A magnified view of part N in the middle.

[0034] Figure 6 for Figure 4 A magnified view of part M in the middle.

[0035] Figure 7 for Figure 1 Bottom structure diagram of the injection molded cover plate assembly.

[0036] Figure 8 This is a three-dimensional view of the cover plate body.

[0037] Figure 9 for Figure 8 Structural diagram in the XY plane.

[0038] Figure 10 for Figure 9 Cross-sectional view in the BB direction.

[0039] Figure 11 This is a three-dimensional diagram of the pole.

[0040] Figure 12 for Figure 11 Structural diagram in the XZ plane.

[0041] Figure 13 for Figure 11 Structural diagram in the XY plane.

[0042] Figure 14 for Figure 13 Cross-sectional view in the CC direction. Detailed Implementation

[0043] The embodiments of this invention provide detailed preparation methods and technical steps, aiming to fully illustrate the specific implementation process of this invention. However, these detailed technical details represent only one specific way of implementing this invention and are not intended to limit the core content of this invention or its scope of protection. Those skilled in the art should understand that these embodiments are for illustrative purposes only and should not be considered as limiting the only or exclusive implementation of this invention.

[0044] like Figure 1-14 The figure shows an injection-molded cover plate assembly according to a specific embodiment of the present invention.

[0045] Includes cover plate body 100 and pole post 200;

[0046] like Figure 11-14 The pole post 200 includes a plate portion 205 and a post portion, such as Figure 1-5 As shown in Figure 8, the column part is coaxially inserted into the pole hole 102 opened along the Z direction on the cover plate body 100, and the plate part 205 connected to the column part is located below the cover plate body 100 along the Z direction.

[0047] like Figure 4-5 On the cover plate body 100, a protrusion 110 is provided with the pole hole 102 as the center, which is upward along the Z direction. The protrusion 110 includes a top protrusion area 112 and a bottom support area 111. The radial spacing of the protrusion area 112 is greater than that of the support area 111. The protrusion area 112 and the support area 111 are connected by a transition area 113 with a gradually changing radial spacing.

[0048] An upper plastic part 300 is provided on the outer periphery of the column portion. The upper plastic part 300 fills the gap between the column portion and the protrusion 110 above the plate portion 205, and surrounds the protrusion 110 above the cover plate body 100.

[0049] like Figure 6 As shown, the thickness T of the cover plate body 100 is 1.5~3mm, the protrusion height H of the protrusion 110 on the cover plate body 100 is (0.8~1.2)×T, the distance h between the protrusion area 112 of the protrusion 110 and the cover plate body 100 is (0.3~0.6)×H, the wall thickness t of the protrusion 110 is (0.3~0.8)×T, and the radial spacing t1 of the support area 111 of the protrusion 110 is (0.5~1.2)×T. The radial distance A between the outer wall surface of the protruding area 112 and the support area 111 is (0.2~0.5)×H. The shortest distance B1 between the protruding area 112 of the protruding part 110 and the columnar part of the pole post 200 is 0.8~1.5mm. The thickness B2 of the upper plastic part 300 surrounding the upper part 110 is 0.5~1.2mm. The minimum thickness B3 of the upper plastic part 300 surrounding the outer periphery of the protruding part 110 is 0.5~1.2mm.

[0050] Among the above parameters, the cover plate body 100, as an important load-bearing component in the entire battery pack structure, provides basic mechanical support for the entire structural system with its thickness T. Simultaneously, as the load-bearing component of the protrusion 110, the cover plate body 100 directly affects the wall thickness t of the protrusion 110, the radial distance t1 of the support area 111 of the protrusion 110, and the protrusion height H of the protrusion 110 on the cover plate body 100. Furthermore, the protrusion height H indirectly affects the distance h between the protrusion head area 112 of the protrusion 110 and the cover plate body 100, as well as the radial distance A between the outer wall surfaces of the protrusion head area 112 and the support area 111. B1, B2, and B3 directly reflect the thickness of the various parts of the upper plastic part 300 surrounding the protrusion 110.

[0051] The synergy among the above parameters improves the microstructural relationship between the pole post, the upper plastic part, and the cover plate body from multiple perspectives.

[0052] On the one hand, TtHh together embody the height distribution relationship of each structural part of the protrusion 110 along the Z direction from the cover plate body 100. The increase of H is conducive to increasing the depth to improve mechanical interlocking and leaving more extension space for the radial spacing A of the protrusion 110, but it is not conducive to the strong connection between the protrusion 110 and the cover plate body 100 and the reliability of resisting torsional force. It also increases the heat dissipation path. The appropriate t ensures the mechanical strength of the protrusion 110 body and balances its position in height. h optimizes the distribution of the protrusion area 112 and the support area 111, and also optimizes heat transfer and reduces local heat concentration. This height distribution relationship jointly optimizes the force-air-heat interaction field.

[0053] Secondly, Hh-t1-A together embody the coordinated distribution of the various structural parts of the protrusion 110 in the radial and Z directions, thereby forming a suitable T-shaped cross-sectional structure for the protrusion 110. The filling of the upper plastic part 300 at point A forms a highly reliable mechanical interlock, preventing it from falling off under high force, balancing the injection depth to avoid injection defects, eliminating interface defects while ensuring mechanical properties, improving airtight reliability, and optimizing the force-air interaction field.

[0054] Thirdly, Hht-B2 optimizes the overall height distribution of each structural part of the protrusion 110 and the upper plastic part 300. Based on TtHh, it ensures the matching of the coverage thickness of the upper plastic part 300 to the protrusion 110, ensures a suitable electrical transmission path and insulation strength, thereby optimizing insulation management on the basis of force and air, and balancing the force-air-electric field.

[0055] Fourthly, A-B1-B2-B3 further supplements the reflection of the filling of the gap between the column part and the protrusion 110 of the upper plastic part 300 and the surrounding of the protrusion 110. It is a direct manifestation of the external structure of the upper plastic part 300, and directly reflects the mechanical changes and insulation path of the upper plastic part 300 in the structure, thereby influencing the electric field.

[0056] Fifthly, HhA-B1 also jointly reflects the height, distance, and interlocking adaptation relationship between the protrusion 110 and the pole post 200. It integrates the coherence and coordination of the protrusion 110 relative to the pole post position in the Z direction (first aspect) and radial direction (second aspect). While forming a good mechanical interlock, it optimizes the effects of injection molding path and subsequent manifold processing, thereby eliminating interface defects (microbubbles, poor filling, etc.) introduced by processing, avoiding the formation of gas permeation channels, and ensuring interface reliability in extreme or long-term working conditions.

[0057] Typically, the cover plate body 100 has two terminal holes 102, which respectively mate with two terminals 200. The two terminals 200 can serve as positive and negative terminals, respectively, for connecting to the positive and negative terminals of the battery cell. The two terminals 200 and the two terminal holes 102 can have the same mating structure or different mating structures. The mating structures between the terminals 200 and the terminal holes 102 described above can be independently applied to the positive terminal and / or the negative terminal, preferably applicable to both the positive and negative terminals. That is, both the positive and negative terminals are connected to the cover plate body 100 by the same upper plastic part 300 surrounding the protrusion 110.

[0058] The positive direction of the Z direction is generally understood as the direction of increasing height from bottom to top. Since the cover body 100 is generally in a horizontal state when the battery is placed vertically, in the description of this invention, the Z direction is also the thickness direction of the cover body 100.

[0059] In this invention, "radial" refers to any direction extending away from the target center of the cross-section on a cross-section perpendicular to the Z direction.

[0060] In some examples, such as Figure 11-14 The pole post 200 has a first step 204, a recess 203, a protrusion 202, and a second step 201 sequentially arranged from the plate 205 upwards. The first step 204 is fitted with an elastic sealing member 700 to seal the plate 205 to the cover plate body 100 from below. The recess 203 and the protrusion 202 form a mechanical interlocking structure between the upper plastic part 300 and the pole post 200. The second step 201 is used to weld to the busbar to realize the current collection and distribution of each battery in the module.

[0061] In this invention, the cylindrical portion of the electrode post 200 passes through the electrode post hole 102 from bottom to top. The plate portion 205, due to its larger diameter than the radius of the electrode post hole 102, is positioned below the cover plate body 100. The plate portion 205 provides upward compressive stress, causing the elastic sealing member 700, fitted around the outer periphery of the first step portion 204, to be sealed and compacted between the cover plate body 100 and the plate portion 205. The upward compressive stress of the plate portion 205 can originate from the upward force provided by the upper plastic part 300 to the electrode post 200, and / or the upward force transmitted by the battery cell to the cover plate body 100.

[0062] In some examples, the protrusion 110 is integrally formed by bending a section of panel around the pole hole 102 from the cover plate body 100 upwards. The bending process is not limited in this invention and can generally be formed by common processing methods such as precision stamping.

[0063] In some examples, the cover body 100 provides a first annular platform 120 above the panel around the pole hole 102 to further form a suitable gradient transition between the support area 111 of the protrusion 110 and the pole hole 102, thereby further optimizing the injection path during the processing of the upper plastic part 300.

[0064] In some examples, the cover plate body 100 is provided with a second annular platform 130 below the panel around the pole hole 102. The second annular platform 130 can improve the interlocking ability between the cover plate body 100 and the lower plastic part 600, so that the lower plastic part 600 extends from the bottom plane of the cover plate body 100 to the space between the plate part 205 and the cover plate body 100, and is circumferentially distributed along the upper end face of the plate part 205 in the Z direction, so as to play a better role in compaction and sealing.

[0065] In some examples, the radial length of the second annular platform 130 of the cover body 100 is greater than that of the first annular platform 120, and the protrusion 110 is disposed on the second annular platform 130 in a radial range extending beyond the first annular platform 120. The second annular platform 130 provides a greater intrinsic thickness to the protrusion 110 relative to the first annular platform 120, while the plate portion 205 below the second annular platform 130 also provides further support for the protrusion 110.

[0066] In some examples, the upper end face of the upper plastic part 300 is flush with the upper end face of the protrusion 202 of the pole post 200.

[0067] In some further optimized examples, t < t1 ≤ H.

[0068] In some further optimized examples, 0.1×T≤t1-t≤0.4×T, 0≤H-t1≤0.3×T.

[0069] In some further optimized examples, h > A.

[0070] In some further optimized examples, 0.2×H≥hA≥0.05×H.

[0071] In some further optimized examples, B2 ≤ B3 < B1.

[0072] In some further optimized examples, 1.25×B2≤B1≤1.6×B2.

[0073] The further optimized parameter relationships are more conducive to the good distribution of structural dimensions between the cover plate body, the upper plastic part, and the pole, improving the connection strength, reliability, and sealing between the structural components, reducing the product weight, and enhancing the product's competitiveness.

[0074] In this invention, the shape of the plate portion 205 is not limited, as long as its major diameter is larger than the radius of the pole hole 102 to achieve positioning below the cover plate body 100. Preferably, the projected area of ​​the plate portion 205 in the Z direction can completely cover the projected area of ​​the pole hole 102 in the Z direction. For example, the shape of the plate portion 205 can be circular, rounded rectangle, ellipse, square, etc. The "major diameter" of the plate portion 205 is the maximum distance from its shape center to its outer perimeter.

[0075] In this invention, the material of the elastic sealing element 700 is not limited, and it is generally an elastic rubber sealing ring that is fitted onto the outer periphery of the first step portion 204 in an elastic contact manner.

[0076] Typically, the cover body 100 also has a lower plastic part 600 on its bottom surface in the Z direction, which is used to insulate and isolate the cover body 100 from the battery cell inside the battery casing below.

[0077] Typically, the cover plate body 100 is also equipped with an explosion-proof valve 400 and an electrolyte injection hole 500, which are used to ensure the explosion-proof safety of the battery and to inject electrolyte, respectively.

[0078] The cover structures made from implementation cases with different parameter designs were assembled into battery packs (cell specifications ≥270Ah) and their performance was tested. The parameter design and test results of each implementation case are shown in Table 1.

[0079] The testing content includes:

[0080] (1) Pressure test: At room temperature of 25℃, the battery cover plate terminal is tested for air tightness in both directions. First, helium is filled from the inside to the outside and pressurized to 1.2MPa, and the pressure is held for 30s. The test is then repeated for a total of 10 cycles. Then, the fixture is flipped over and helium is filled from the outside to the inside and pressurized to 1.2MPa. The pressure is held for 30s. The test is then repeated for a total of 10 cycles. If no leakage is detected in each cycle in both directions, the air tightness of the battery cover plate terminal is deemed to be qualified.

[0081] (2) Thrust test: At room temperature of 25℃, a thrust of 1000N is applied to the terminals of the battery cover along the three orthogonal directions of the X-axis, Y-axis and Z-axis, and the application is repeated 10 times in each direction. After completion, the airtightness is verified by helium mass spectrometry leak detection method, the appearance of the terminals is visually inspected for deformation, and the cover is disassembled to check for cracks in the internal plastic parts; if the airtightness is qualified, the terminals are not deformed and the plastic parts are not cracked, the mechanical strength of the battery cover is deemed qualified.

[0082] (3) Leakage current detection: The test is conducted at room temperature of 25℃ and relative humidity of 45%~75%. After connecting the positive terminal of the high voltage tester to the pole and the negative terminal to the aluminum plate and ensuring reliable contact, the voltage is increased to 1500VDC at a rate of 500~1000V / s. The voltage is maintained for 60s and the leakage current value is read after stabilization.

[0083] Table 1

[0084]

[0085]

[0086]

[0087] The results of each embodiment in Table 1 above fully demonstrate the synergistic optimization effect of the multi-parameter coupling of the present invention on the force-air-thermal-electric multi-field of the microstructure between the pole post, the upper plastic part, and the cover plate body. Under the condition of fully satisfying the dimensional relationship of multi-parameter coordination, the embodiments of the present invention exhibit the following mechanical properties: when the pole post is subjected to a thrust of 1000N / 10 cycles, the upper plastic part shows no cracking, and the contact effect between the upper plastic part and the aluminum plate / pole post is good. Simultaneously, in terms of airtightness, the pole post shows no leakage under 1.2MPa air pressure for 30 seconds from the inside out / from the outside in, indicating good airtightness. Regarding insulation, the leakage current between the pole post and the aluminum plate is <2mA under 1500VDC voltage. Furthermore, in terms of thermal management, the aluminum plate is not affected by the welding heat after the cover is welded, and there is no deformation during the pole post thrust test. The explosion-proof valve helium test is normal, and the leakage rate is <10%. -7 pa.m 3 / s.

[0088] Comparative Example 1 altered the base thickness T of the cover plate body, which directly and indirectly affected the synergistic combination of t, H, h, and A. As a result, the protrusion 110, which is based on basic mechanical support, and the pole 200 no longer have good overall dimensional compatibility. The force-air-heat field is disrupted, which not only causes deformation due to welding heat, but also leads to a reduction in the pole's resistance to thrust deformation and air leakage defects.

[0089] Comparative Examples 2 and 3 changed the fit of t and t1 respectively, which disrupted the distribution relationship of each structural part of the protrusion 110 in the Z direction and radial direction. Similarly, the basic mechanical properties could not be effectively guaranteed. The protrusion 110 was insufficient in terms of processing and forming and stress strength, and cracking problems occurred.

[0090] Comparative Example 2 further combines Comparative Examples 4-5 (H, h) and Comparative Example 8 (B2 / B3) to demonstrate the balancing effect of Hht-B2 on force-air-electricity.

[0091] Comparative Example 3, in conjunction with Comparative Examples 4-5 (H, h) and Comparative Example 6 (A), introduces the leakage problem, illustrating the role of Hh-t1-A in jointly optimizing the force-air interaction field.

[0092] Comparative Examples 4-7 also demonstrated that by changing HhA-B1, the mismatched design caused the upper plastic part to detach or crack, resulting in the destruction of air tightness. They also confirmed that the relative positional relationship between the protrusion 110 and the pole affects the force-air balance through the optimization of the injection molding path and the influence of processing coherence.

[0093] Comparative Examples 6-8 also reflect the intuitive dimensional design changes of the upper plastic part by changing A-B1-B2-B3. The structural mechanics and insulation path can be considered from the perspective of the dimensional design of the upper plastic part, which also explains the reasonable effect of the force-electric field, and is consistent with the previous synergistic effect.

[0094] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions, and variations to the above embodiments within the scope of the present invention. Furthermore, without contradiction, those skilled in the art can combine and integrate different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. An injection-molded cover plate assembly, comprising a cover plate body (100) and a pole post (200); The pole post (200) includes a plate part (205) and a column part. The column part is coaxially inserted into the pole post hole (102) opened along the Z direction on the cover plate body (100). The plate part (205) connected to the column part is located below the cover plate body (100) along the Z direction. On the cover plate body (100), a protrusion (110) is provided with the pole hole (102) as the center, which is upward along the Z direction. The protrusion (110) includes a top protrusion area (112) and a bottom support area (111). The radial spacing of the protrusion area (112) is greater than that of the support area (111). The protrusion area (112) and the support area (111) are connected by a transition area (113) with a gradually changing radial spacing. An upper plastic part (300) is provided on the outer periphery of the column part. The upper plastic part (300) fills the gap between the column part and the protrusion (110) above the plate part (205) and surrounds the protrusion (110) above the cover plate body (100). The thickness T of the cover plate body (100) is 1.5~3mm, the protrusion height H of the protrusion (110) on the cover plate body (100) is (0.8~1.2)×T, the distance h between the protrusion area (112) of the protrusion (110) and the cover plate body (100) is (0.3~0.6)×H, the wall thickness t of the protrusion (110) is (0.3~0.8)×T, the radial spacing t1 of the support area (111) of the protrusion (110) is (0.5~1.2)×T, and the protrusion area... The radial distance A between the outer wall of the protruding area (112) and the support area (111) of (112) is (0.2~0.5)×H. The shortest distance B1 between the protruding area (112) of the protruding part (110) and the column part of the pole post (200) is 0.8~1.5mm. The thickness B2 of the upper plastic part (300) surrounding the upper part (110) is 0.5~1.2mm. The minimum thickness B3 of the upper plastic part (300) surrounding the outer periphery of the protruding part (110) is 0.5~1.2mm.

2. The injection-molded cover plate assembly according to claim 1, characterized in that, The cover plate body (100) is provided with two pole hole (102), which respectively correspond to two poles (200) as positive pole and negative pole. The positive pole and the negative pole are connected to the cover plate body (100) by the same upper plastic part (300) surrounding the protrusion (110).

3. The injection-molded cover plate assembly according to claim 1, characterized in that, The pole post (200) has a first step (204), a recess (203), a protrusion (202), and a second step (201) sequentially from the plate (205) upwards; wherein the first step (204) is provided with an elastic sealing element (700) on its outer periphery, which is used to seal the plate (205) with the cover plate body (100) from below; the recess (203) and the protrusion (202) are used to form a mechanical interlocking structure between the upper plastic part (300) and the pole post (200); the second step (201) is used to weld with the busbar.

4. The injection-molded cover plate assembly according to claim 1, characterized in that, The column portion of the pole post (200) passes through the pole post hole (102) from bottom to top. The plate portion (205) is located below the cover plate body (100) because its large diameter is larger than the radius of the pole post hole (102). The plate portion (205) provides upward compressive stress, so that the elastic seal (700) sleeved on the outer periphery of the first step portion (204) is sealed and compacted between the cover plate body (100) and the plate portion (205).

5. The injection-molded cover plate assembly according to claim 1, characterized in that, The protrusion (110) is integrally formed by bending a section of panel around the pole hole (102) upward through the cover plate body (100).

6. The injection-molded cover plate assembly according to claim 1, characterized in that, The cover plate body (100) is provided with a first ring platform (120) above the panel around the pole hole (102) to further form a suitable gradient transition between the support area (111) of the protrusion (110) and the pole hole (102); Preferably, the cover plate body (100) is provided with a second ring platform (130) below the panel around the pole hole (102), and the lower plastic part (600) extends from the bottom plane of the cover plate body (100) to the space between the plate part (205) and the cover plate body (100), and is distributed circumferentially along the upper end surface of the plate part (205) in the Z direction.

7. The injection-molded cover plate assembly according to claim 6, characterized in that, The radial length of the second ring platform (130) of the cover plate body (100) is greater than that of the first ring platform (120), and the protrusion (110) is provided on the second ring platform (130) within the radial range that extends beyond the first ring platform (120).

8. The injection-molded cover plate assembly according to claim 1, characterized in that, The upper end face of the upper plastic part (300) is flush with the upper end face of the protrusion (202) of the pole post (200); Preferably, t < t1 ≤ H; Preferably, 0.1×T≤t1-t≤0.4×T, 0≤H-t1≤0.3×T; Preferably, h > A; Preferably, 0.2×H≥hA≥0.05×H; Preferably, B2 ≤ B3 < B1; Preferably, 1.25×B2≤B1≤1.6×B2.

9. The injection-molded cover plate assembly according to claim 1, characterized in that, An explosion-proof valve (400) and a liquid injection hole (500) are also provided on the cover plate body (100).

10. A battery comprising a casing and an injection-molded cover assembly as described in any one of claims 1-9, wherein the casing and the injection-molded cover assembly together enclose a cavity for accommodating a battery cell, and the electrode plates of the battery cell are connected to the terminals on the injection-molded cover assembly according to their polarity (positive and negative).

Images