Lower plastic part and cover plate assembly

Abstract

The invention relates to a lower plastic part and cover plate assembly, comprising a plastic part main body mounted between a cover plate and a battery cell; an anti-explosion valve is arranged on the cover plate, and a supporting part is arranged on the plastic part main body; part of the supporting piece is located between the plastic piece body and the anti-explosion valve, and the supporting piece is used for supporting the anti-explosion valve. The lower plastic part is a part between the battery cover plate and the battery cell, and the supporting part is located on the side, facing the anti-explosion valve, of the plastic part body and used for supporting the anti-explosion valve. The supporting piece can be designed into a single type, an independent type or a mixed type, the top end attaching part is a smooth plane, all the attaching parts are kept on the same horizontal plane, and uniform supporting is achieved. Reverse support is provided under the negative pressure working conditions of vacuumizing, liquid injection and the like, unexpected sinking of the anti-explosion valve, especially a nick and thinned weak area is prevented, meanwhile, the fracture pressure relief function of the anti-explosion valve under the abnormal high pressure is not intervened, it is guaranteed that the anti-explosion valve can be fractured along a preset path when the anti-explosion valve is abnormal, and gas can be rapidly exhausted.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery technology, and in particular to a lower plastic part and a cover assembly. Background Technology

[0002] In the cover assembly, the lower plastic component, also called the lower insulating component or support plastic component, is installed inside the cover and close to the battery cell. It is a core auxiliary component, and its core functions are to achieve insulation isolation, structural support, sealing protection, and functional adaptation. It also connects the cover with key components such as the battery cell and explosion-proof valve, ensuring the overall reliability of the battery. The explosion-proof film is a key safety structure on the battery cover or casing. It is usually made of metal or composite material. Through thinning and laser marking, weak areas are formed. Its core function is to rupture according to a preset threshold and path when abnormal high voltage occurs inside the battery, quickly releasing gas and preventing the battery from exploding or deforming violently.

[0003] However, in the battery manufacturing process, after the battery cell is packaged, steps such as vacuuming and electrolyte injection are required. A significant pressure difference is generated between the inside of the battery and the external environment, causing the explosion-proof valve to be subjected to external pressure directed into the battery, which makes the explosion-proof valve prone to inward deformation. Summary of the Invention

[0004] This application provides a lower plastic part and a cover plate assembly, which can prevent the explosion-proof valve from denting and deforming during the battery manufacturing process.

[0005] According to one aspect of this application, a lower plastic part is provided, wherein an explosion-proof valve is provided on the cover plate, and the plastic part body is installed between the cover plate and the battery cell;

[0006] A support member, part of which is located between the plastic body and the explosion-proof valve, is used to support the explosion-proof valve.

[0007] In one embodiment, a pressure relief cavity is provided on the plastic body, and the pressure relief cavity is recessed toward the battery cell; the projection of the explosion-proof valve on the plastic body is located within the projection of the pressure relief cavity on the plastic body, the pressure relief cavity is used to buffer electrolyte and gas, and the support member is located inside the pressure relief cavity.

[0008] In one embodiment, the support includes a plurality of sub-support elements, each of the plurality of sub-support elements including a fitting portion facing the explosion-proof valve; the plurality of fitting portions are spaced apart, and the sub-support elements support the explosion-proof valve through the plurality of fitting portions.

[0009] In one embodiment, a plurality of the sub-support elements are interconnected, and at least some of the sub-support elements are fixedly connected to the pressure relief chamber.

[0010] In one embodiment, the plurality of sub-support elements are arranged independently of each other, and at least some of the sub-support elements are fixedly connected to the pressure relief chamber.

[0011] In one embodiment, the support is configured in a wave shape, the support comprising a plurality of alternating crests and troughs; the fitting portion is configured as crests.

[0012] In one embodiment, at least some of the sub-support elements are interconnected, at least some of the sub-support elements are independently arranged, and at least some of the sub-support elements are fixedly connected to the pressure relief chamber.

[0013] In one embodiment, at least a portion of the projection of the support member onto the plastic body lies within the projection of the explosion-proof valve onto the plastic body.

[0014] In one embodiment, the pressure relief chamber has a plurality of through first slots, and the support member has a plurality of through second slots.

[0015] In one embodiment, the plastic body includes a first lower plastic component and a second lower plastic component, and a gap is provided between the first lower plastic component and the second lower plastic component;

[0016] The pressure relief cavity is located on the first lower plastic part; the pressure relief cavity is located on the second lower plastic part; the pressure relief cavity is located between the first lower plastic part and the second lower plastic part, and at least part of the gap is located inside the pressure relief cavity.

[0017] This application has the following beneficial effects:

[0018] The lower plastic part is the component between the battery cover and the battery cell. The support component is located on the side of the plastic part facing the explosion-proof valve and is used to support the explosion-proof valve. It provides reverse support under negative pressure conditions such as vacuuming and liquid injection to prevent the explosion-proof valve, especially in areas with scoring or thinning, from unexpectedly denting. At the same time, it does not interfere with the pressure relief function of the explosion-proof valve in case of abnormal high pressure, ensuring that the explosion-proof valve can rupture along a preset path in case of abnormality, and the gas can be discharged quickly. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall three-dimensional structure of an embodiment of this application. Figure 1 .

[0020] Figure 2 This is a schematic diagram of the overall three-dimensional structure of an embodiment of this application. Figure 2 .

[0021] Figure 3 This is a schematic diagram of the overall three-dimensional structure of an embodiment of this application. Figure 3 .

[0022] Figure 4 This is a three-dimensional structural diagram of the cover plate assembly in one embodiment of this application.

[0023] Figure 5 This is a cross-sectional view of a cover plate assembly according to an embodiment of this application.

[0024] Figure 6 This is a three-dimensional structural diagram of the second lower plastic component in one embodiment of this application.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1000, Lower plastic part;

[0027] 100. Main body of the plastic part; 110. First lower plastic part; 120. Second lower plastic part; 130. Gap;

[0028] 140. Pressure relief chamber; 141. First slot;

[0029] 150. Support component; 151. Sub-support element; 152. Second slot; 153. Fitting part. Detailed Implementation

[0030] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0031] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0036] See appendix Figure 1 -Appendix Figure 2 , attached Figure 1 -Appendix Figure 2 A schematic diagram of the overall structure of the lower plastic part according to an embodiment of this application is shown. An explosion-proof valve is provided on the cover plate, including the plastic part body 100, which is installed between the cover plate and the battery cell.

[0037] Support member 150, part of which is located between the plastic body 100 and the explosion-proof valve, is used to support the explosion-proof valve.

[0038] In some embodiments, the lower plastic part is a core auxiliary component between the battery cover and the battery cell, and its function is to ensure battery safety and reliability through insulation, structural support, and functional adaptation. The support member 150 is located on the side of the plastic part body 100 facing the explosion-proof valve, and is directly attached to the inner side of the explosion-proof valve or set at a certain distance. It provides reverse support under negative pressure conditions such as vacuuming and liquid injection to prevent the explosion-proof valve, especially in the scored and thinned weak areas, from unexpectedly denting. At the same time, it does not interfere with the pressure relief function of the explosion-proof valve when it is under abnormally high pressure.

[0039] The support member 150 can be designed as a single, independent, or hybrid type. The top fitting portion 153 is a smooth plane, and all fitting portions 153 maintain the same horizontal plane to achieve uniform support. The support member 150 makes close contact with the inside of the explosion-proof valve through the fitting portions 153, providing reverse support force under negative pressure conditions, dispersing the stress on the explosion-proof valve, and avoiding dents or scoring deformation caused by local stress concentration. The support member 150 adopts a non-continuous contact design, such as spaced arrangement or a wavy structure, and the fitting portions 153 avoid scoring paths to ensure that the explosion-proof valve can rupture along a preset path in case of abnormality, allowing gas to be discharged quickly.

[0040] See appendix Figure 2 -Appendix Figure 3 and attached Figure 5 The plastic body 100 is provided with a pressure relief cavity 140, which is recessed towards the battery cell; the pressure relief cavity 140 is used to buffer electrolyte and gas, and the support member 150 is located inside the pressure relief cavity 140.

[0041] In some embodiments, the pressure relief cavity 140 is formed on the side of the plastic body 100 facing the battery cell, and has an overall inwardly recessed cavity structure. That is, a groove is cut into the side of the plastic body 100 near the battery cell. The horizontal projection contour of the cavity corresponds to the explosion-proof valve on the cover plate, and the projection area is larger than the area of ​​the explosion-proof valve to ensure full coverage. The cavity depth of the pressure relief cavity 140 is 1.5mm-3mm. The specific depth can be designed according to the internal assembly gap of the battery. The design of the pressure relief cavity 140 should not interfere with the installation of the battery cell and the cover plate.

[0042] In some embodiments, the cavity wall of the pressure relief chamber 140 is a smoothly transitioned slope or straight surface without sharp edges to prevent liquid or gas accumulation. The cavity opening faces the cover plate, and the bottom of the cavity on the side away from the explosion-proof valve is a flat mounting reference surface for mounting the support member 150. The support member 150 is integrally integrated into the bottom area of ​​the pressure relief chamber 140, and is integrally injection molded with the plastic body 100 without splicing gaps to prevent electrolyte seepage or structural loosening.

[0043] In some embodiments, the support member 150 is detachably installed inside the pressure relief chamber 140. When the support member 150 is damaged, it can be replaced and repaired separately, thereby reducing the cost of use.

[0044] In some embodiments, the height of the support member 150 is higher than the cavity opening plane of the pressure relief chamber 140 by 1mm-2mm, ensuring that the fitting part 153 can make tight contact with the inside of the explosion-proof valve after assembly, providing effective support. The specific height can be designed according to actual needs. The bottom end of the support member 150 is fixedly connected to the bottom of the pressure relief chamber 140 to form a stable support structure.

[0045] In some embodiments, the periphery of the pressure relief cavity 140 does not interfere with the structure of the plastic body 100, such as the electrode through holes and sealing grooves. The electrode through holes are located on both sides of the pressure relief cavity 140, corresponding to the positive and negative electrode positions of the cover plate. The sealing groove surrounds the outer ring of the pressure relief cavity 140 to ensure that the insulation and sealing functions are not affected by the cavity structure.

[0046] In some embodiments, a buffer gap of 1mm-2mm is reserved between the battery cell and the pressure relief chamber 140 after assembly to prevent the battery cell from directly squeezing the chamber.

[0047] In some embodiments, the buffering function of the pressure relief chamber 140 and the supporting function of the support member 150 do not conflict with each other. The pressure relief chamber 140, through its recessed space, accommodates splashed electrolyte and buffers gas impacts, preventing the electrolyte and gas from directly acting on the weak areas of the explosion-proof valve. The support member 150 is located inside the cavity and only contacts the explosion-proof valve through its top fitting portion 153, without obstructing the buffer space of the cavity. The electrolyte and gas can flow in the gaps of the support member 150, achieving dual protection of buffering and support.

[0048] In some embodiments, when the battery swings or vibrates significantly, electrolyte splashes into the pressure relief chamber 140. The chamber can temporarily store a small amount of electrolyte to prevent it from directly impacting the explosion-proof valve. Excess electrolyte flows back to the battery cell through the guiding effect of the chamber wall and will not remain in the chamber.

[0049] In some embodiments, the negative pressure generated by vacuuming is transmitted through the gaps in the support member 150 to balance the gas pressure on both sides of the explosion-proof valve and reduce the risk of denting. In the event of abnormal pressure relief, after diffusion through the pressure relief chamber 140, the gas is ejected from the rupture point of the explosion-proof valve, reducing the impact force of the gas ejection.

[0050] See appendix Figure 2 and attached Figure 5 The support member 150 includes a plurality of sub-support elements 151, each of which includes a contact portion 153 facing the explosion-proof valve; the plurality of contact portions 153 are arranged at intervals, and the sub-support elements 151 support the explosion-proof valve through the plurality of contact portions 153.

[0051] In some embodiments, the plastic body 100 is an injection-molded insulating part made of materials such as PP or PPS. It is installed between the battery cover and the battery cell and serves as an integrated carrier for the pressure relief chamber 140 and the support 150. It also has basic structures such as terminal through holes, sealing grooves, and bottom positioning protrusions, and undertakes core auxiliary functions such as insulation, fixation, and sealing.

[0052] In some embodiments, 3 to 6 sub-support elements 151 are typically provided. The specific number can be adjusted according to the size of the explosion-proof valve. For example, a circular explosion-proof valve may be provided with 3 evenly distributed sub-support elements 151, arranged in a ring, symmetrical or linear intervals, avoiding the scoring or thinning of weak areas of the explosion-proof valve.

[0053] In some embodiments, the contact portion 153 is the contact end face of each sub-support element 151 facing the top of the explosion-proof valve. The contact portion 153 is a smooth, small-area contact surface, such as a circular or rectangular end face. Its surface is slightly roughened to increase friction and improve the stability of the direct contact with the explosion-proof valve.

[0054] In some embodiments, multiple mating portions 153 are distributed at intervals along the contour of the pressure relief cavity 140, with a center-to-center distance of 3mm-5mm between adjacent mating portions 153. The specific distance can be designed and selected according to actual needs, forming a non-continuous contact support surface rather than a complete plane.

[0055] In some embodiments, multiple fitting portions 153 are arranged at intervals to form line contact or small-area contact with the inner side of the explosion-proof valve, avoiding the full-fitting of traditional planar supports, which can easily lead to airflow obstruction and thus local stress concentration. This reduces unexpected dents in the explosion-proof valve under negative pressure conditions such as vacuuming and liquid injection.

[0056] In some embodiments, each fitting portion 153 independently bears a portion of the supporting force. Through various arrangement methods, the explosion-proof valve is subjected to uniform force, especially protecting the vulnerable area around the notch, and preventing excessive local force from causing deformation or premature breakage of the notch. The gaps between the fitting portions 153 can serve as airflow channels to balance the air pressure between the explosion-proof valve and the inside of the battery during vacuuming. In case of abnormal pressure relief, gas can be quickly discharged through the gaps without obstructing the rupture path of the explosion-proof valve.

[0057] In some embodiments, the total support area of ​​the fitting portion 153 is controlled at 5%-20% of the area of ​​the explosion-proof valve, which ensures support stability and provides sufficient space for gas flow and pressure relief. All fitting portions 153 avoid the scoring path of the explosion-proof valve.

[0058] See appendix Figure 2 and attached Figure 5Multiple sub-support elements 151 are interconnected, and at least some of the sub-support elements 151 are fixedly connected to the pressure relief chamber 140; the support member 150 is configured in a wave shape, and the support member 150 includes multiple alternating peaks and troughs; the fitting part 153 is configured as a peak.

[0059] In some embodiments, multiple sub-support elements 151 are integrally formed continuous structures, together constituting a complete wave-shaped support 150. Specifically, adjacent sub-support elements 151 are seamlessly connected through trough regions, that is, the end of the trough of the previous sub-support element 151 and the beginning of the trough of the next sub-support element 151 are integrally injection molded to form a continuous wave structure without splicing gaps.

[0060] This connection method allows all sub-support elements 151 to form a force-bearing community, preventing individual sub-support elements 151 from falling off or deforming under stress. At the same time, it gives the support 150 as a whole good elastic deformation capability, so that the impact force when the explosion-proof valve is opened can be buffered and relieved by the overall deformation.

[0061] In some embodiments, sub-support elements 151 at certain special locations are further reinforced with a boss on the outer side of the trough. This boss is embedded in a pre-set groove at the bottom of the pressure relief chamber 140, further enhancing the connection's firmness. This fixing structure ensures that the support 150 will not shift or loosen when subjected to the pressure and gas impact of the explosion-proof valve, guaranteeing support stability. The wave-shaped structure of the support 150 is a regular sine wave pattern, with alternating and evenly distributed peaks and troughs. The distance between two adjacent peaks is set to 3mm-5mm. This distance ensures uniform support for the explosion-proof valve while allowing sufficient clearance for electrolyte and gas flow. Simultaneously, the transition areas between peaks and troughs are designed with rounded edges to prevent stress concentration that could damage the support 150 itself.

[0062] In some embodiments, the tip of the corrugated fitting portion 153 is not a sharp structure, but is designed as a smooth plane with a width of 0.8mm-1.2mm. This plane is adapted to the contact surface inside the explosion-proof valve, which can increase the contact area with the explosion-proof valve, improve support stability, and avoid damage to the weak structure of the explosion-proof valve due to excessive local pressure. In addition, the top surface of each corrugated fitting portion 153 is kept on the same horizontal plane, ensuring that the supporting force on the explosion-proof valve is evenly distributed, and completely solving the stress concentration problem that is prone to occur in planar contact. When negative pressure is generated inside the battery, the corrugated fitting portion 153 bears the pressure first, and then the support member 150 can buffer the pressure through the slight deformation of the corrugated structure, which can not only ensure the normal operation of the explosion-proof valve, but also prevent abnormal damage such as breakage due to excessive instantaneous force.

[0063] See appendix Figure 2 and attached Figure 5 -Appendix Figure 6Multiple sub-support elements 151 are set independently of each other, and at least some of the sub-support elements 151 are fixedly connected to the pressure relief chamber 140.

[0064] In some embodiments, the multiple sub-support elements 151 are completely separate individual structures without any direct connection or integrally formed joints, and each sub-support element 151 has independent load-bearing capacity. The shape of a single sub-support element 151 can be designed as a columnar, sheet-like, or low-profile boss structure, with its height matching the position of the explosion-proof valve to ensure that the top fitting part 153 can make precise contact with the inside of the explosion-proof valve.

[0065] In some embodiments, all independent sub-support elements 151 are symmetrically or evenly distributed in a ring along the pressure relief chamber 140, with a center-to-center distance of 3mm-6mm between adjacent sub-support elements 151. During arrangement, the elements must strictly avoid the scoring or thinning weak areas of the explosion-proof valve, ensuring that the contact portion 153 acts only on the non-vulnerable areas of the explosion-proof valve. The top contact portions 153 of all sub-support elements 151 are kept on the same horizontal plane to avoid uneven stress on the explosion-proof valve due to height differences.

[0066] In some embodiments, at least 50% of the sub-support elements 151 are integrally injection molded and fixedly connected to the bottom of the pressure relief cavity 140. The sub-support elements 151, the plastic body 100, and the pressure relief cavity 140 are injection molded simultaneously, forming a seamless connection between the bottom and the cavity bottom without assembly gaps. This effectively prevents structural loosening or corrosion failure caused by electrolyte seepage. The remaining sub-support elements 151 can be fixedly mounted on other sub-support elements 151 without being directly connected to the pressure relief cavity 140, thereby increasing the fluidity of the electrolyte or gas and avoiding excessive density that could affect the flow of the electrolyte or gas.

[0067] In some embodiments, the independent design allows each sub-support element 151 to independently bear the support force. When the explosion-proof valve is under negative pressure, the force is distributed and transmitted through multiple independent contact points, completely avoiding stress concentration that may occur in the continuous structure. Furthermore, the small deformation of a single sub-support element 151 will not affect other elements, resulting in stronger overall support stability.

[0068] In some embodiments, the gaps between the independent sub-support elements 151 are larger than those in a connected structure. This reduces the risk of the explosion-proof valve denting during vacuuming, and allows the electrolyte to flow freely through the gaps during electrolyte injection or battery vibration, preventing it from stagnating in the support area. This ensures both a buffering effect and avoids corrosion problems caused by electrolyte accumulation. Since the independent sub-support elements 151 are not obstructed by a continuous structure, gas can quickly diffuse and escape through the gaps when the explosion-proof valve ruptures and releases pressure, without obstructing the pressure relief path. Furthermore, the small size of each individual sub-support element 151 prevents interference with the rupture path of the explosion-proof valve, ensuring smooth pressure relief.

[0069] See appendix Figure 2and attached Figure 5 -Appendix Figure 6 At least some of the sub-support elements 151 are interconnected, at least some of the sub-support elements 151 are independently arranged, and at least some of the sub-support elements 151 are fixedly connected to the pressure relief chamber 140.

[0070] In some embodiments, the central region of the pressure relief chamber 140, i.e., the core stress-bearing area of ​​the explosion-proof valve, is provided with a set of wave-shaped connecting structures, consisting of multiple interconnected sub-support elements 151, which bear the main supporting force and provide elastic buffering. The edge region of the pressure relief chamber 140, i.e., the outer ring non-core area of ​​the explosion-proof valve, has multiple independent sub-support elements 151 evenly distributed, without any interconnection or connection to the wave-shaped structure, serving as auxiliary support and positioning functions. The top fitting portions 153 of all sub-support elements 151 are kept on the same horizontal plane to ensure uniform force distribution on the explosion-proof valve.

[0071] In some embodiments, the two ends of the wave-shaped structure, i.e. the end of the trough, are fixedly connected to the bottom of the pressure relief chamber 140 or integrally injection molded. Local fixing points can be selectively added to the middle trough area, such as a reinforcing boss for every two troughs, to improve the overall rigidity.

[0072] In some embodiments, the hybrid design can achieve complementary support performance. The corrugated structure of the connected sub-components has elastic deformation capability, which can buffer pressure through slight deformation during vacuum negative pressure, avoiding damage to the explosion-proof valve caused by rigid support. The independent sub-components provide rigid support, enhance the overall support stability, prevent excessive deformation of the corrugated structure, and achieve dual support of elastic buffering and rigid positioning. During liquid injection or depressurization, electrolyte and gas can flow freely through the channels without stagnating in the support area, ensuring the buffering function of the pressure relief chamber 140 and avoiding corrosion caused by electrolyte accumulation.

[0073] See appendix Figure 1 -Appendix Figure 2 At least part of the projection of the support member 150 on the plastic body 100 is located within the projection of the explosion-proof valve on the plastic body 100.

[0074] In some embodiments, using the mating surface of the plastic body 100 as the projection reference plane, the explosion-proof valve is projected onto the plastic body 100 in a direction perpendicular to the reference plane, forming the explosion-proof valve projection area, denoted as area A. Simultaneously, the support member 150 is projected in the same direction, forming the support member 150 projection area, denoted as area B. At least 50% of the area in area B is located within area A, and the projection of the critical force-bearing mating portion 153 must completely fall within area A. Only the projections of some sub-support element 151 connection structures, such as wavy connecting sections and root fixing structures, may extend beyond area A, but must avoid other functional areas such as poles and sealing grooves.

[0075] In some embodiments, the projection of the fitting portion 153 falls entirely within the projection area of ​​the explosion-proof valve, ensuring that the fitting portion 153 can accurately contact the inner side of the explosion-proof valve after assembly, providing direct and effective reverse support, and avoiding support misalignment due to projection offset, which would prevent the explosion-proof valve from collapsing under negative pressure. The projections of some support structures, such as connecting sections and fixed ends, can extend beyond the projection area of ​​the explosion-proof valve, making full use of the remaining space in the pressure relief chamber 140 to arrange the fixed structure, thereby improving the connection strength and structural stability of the support member 150 without increasing the volume of the plastic body 100.

[0076] See appendix Figure 1 -Appendix Figure 3 The pressure relief chamber 140 has multiple through first slots 141, and the support member 150 has multiple through second slots 152.

[0077] In some embodiments, the first slot 141 and the second slot 152 are airflow and electrolyte flow channels, which further improve the buffering efficiency of the pressure relief chamber 140, balance the air pressure, and prevent liquid accumulation and corrosion, while not affecting the support stability of the support member 150.

[0078] In some embodiments, the first slots 141 are formed at the bottom and wall of the pressure relief chamber 140, distributed in the area of ​​the non-sub-support element 151, and do not overlap with the fixing structure of the support 150, such as the root reinforcement platform or the trough fixing end, to avoid weakening the connection strength. One to two slots are formed per square centimeter, and the overall number is adjusted according to the area of ​​the pressure relief chamber 140, and they are evenly arranged in a ring or symmetrical pattern to ensure uniform flow of airflow and electrolyte.

[0079] In some embodiments, the perforations are primarily circular, with some cavity wall perforations designed as elongated slots to accommodate different flow requirements. During vacuuming, the perforations can quickly balance the gas pressure inside the pressure relief chamber 140 and the cell side, reducing the instantaneous pressure difference across the explosion-proof valve and further mitigating the risk of denting. During depressurization, gas can quickly enter the pressure relief chamber 140 from the cell side through the perforations and then exit through the gap in the support member 150, increasing the depressurization rate and reducing internal gas pressure accumulation.

[0080] In some embodiments, the second slot 152 is formed in the trough region and the connecting section, avoiding the crest fitting portion 153. One or two slots are formed in each trough, and the slots in adjacent troughs are staggered to avoid affecting the support strength of the crest. The slots do not damage the support surface of the fitting portion 153, nor do they weaken the structural rigidity of the sub-support element 151.

[0081] See appendix Figure 1 -Appendix Figure 3 The plastic body 100 includes a first lower plastic part 110 and a second lower plastic part 120, with a gap 130 provided between the first lower plastic part 110 and the second lower plastic part 120.

[0082] The pressure relief chamber 140 is located on the first lower plastic part 110; the pressure relief chamber 140 is located on the second lower plastic part 120; the pressure relief chamber 140 is located between the first lower plastic part 110 and the second lower plastic part 120, and at least part of the gap 130 is located inside the pressure relief chamber 140.

[0083] In some embodiments, the plastic body 100 has a split structure, with a left-right split design, consisting of a first lower plastic component 110 and a second lower plastic component 120, which are independently injection molded. The gap 130 is a reserved space after the first lower plastic component 110 and the second lower plastic component 120 are assembled; it is elongated or annular, with a width of 0.2mm-0.5mm, extending along the mating surfaces of the two components. The gap 130 can serve as an auxiliary airflow channel, forming a flow network with the first slot 141 of the pressure relief chamber 140 and the second slot 152 of the support member 150, further improving air pressure balance efficiency.

[0084] In some embodiments, the pressure relief cavity 140 is integrally formed on the side of the first lower plastic component 110 facing the battery cell, and has a recessed cavity structure. Its horizontal projection falls entirely within the area of ​​the first lower plastic component 110 and does not extend into the second lower plastic component 120. The support member 150 is integrated into the bottom of the pressure relief cavity 140 and is integrally injection molded with the first lower plastic component 110. The projection of the fitting portion 153 precisely corresponds to the explosion-proof valve area on the cover plate.

[0085] In some embodiments, the pressure relief cavity 140 is integrally formed on the side of the second lower plastic part 120 facing the battery cell. The cavity outline, depth and integrated design of the support 150 are completely consistent with the above embodiments, except that the carrier is changed from the first lower plastic part 110 to the second lower plastic part 120.

[0086] In some embodiments, the pressure relief cavity 140 is a bridging cavity, the contour of which simultaneously covers the mating area of ​​the first lower plastic component 110 and the second lower plastic component 120. That is, the mating end of the first lower plastic component 110 has a semi-cavity structure, and the mating end of the second lower plastic component 120 has a corresponding semi-cavity structure. After assembly, the two are joined to form a complete pressure relief cavity 140. The middle section of the gap 130 is directly located inside the pressure relief cavity 140, that is, the cavity of the pressure relief cavity 140 includes a gap 130. This gap 130 extends along the length of the pressure relief cavity 140, dividing the interior of the pressure relief cavity 140 into two independent sub-cavities, but without affecting the overall buffering function.

[0087] See appendix Figure 4 -Appendix Figure 5 A cover plate structure includes a cover plate and a lower plastic part 1000. The lower plastic part 1000 includes a main body 100. The main body 100 is disposed between the cover plate and the battery cell, which can prevent the explosion-proof valve from being dented or deformed.

[0088] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A lower plastic part, wherein an explosion-proof valve is provided on the cover plate, characterized in that, include: The plastic body (100) is installed between the cover plate and the battery cell; A support member (150) is located between the plastic body (100) and the explosion-proof valve, and the support member (150) is used to support the explosion-proof valve.

2. The lower plastic part according to claim 1, characterized in that, The plastic body (100) is provided with a pressure relief cavity (140), which is recessed toward the battery cell; the projection of the explosion-proof valve on the plastic body (100) is located within the projection of the pressure relief cavity (140) on the plastic body (100); The pressure relief chamber (140) is used to buffer electrolyte and gas, and the support (150) is located inside the pressure relief chamber (140).

3. The lower molded part according to claim 2, characterized in that, The support member (150) includes a plurality of sub-support elements (151), each of the plurality of sub-support elements (151) including a fitting portion (153) facing the explosion-proof valve. Multiple bonding portions (153) are arranged at intervals, and the sub-support element (151) supports the explosion-proof valve through the multiple bonding portions (153).

4. The lower molded part according to claim 3, characterized in that, The plurality of said sub-support elements (151) are interconnected, and at least some of said sub-support elements (151) are fixedly connected to said pressure relief chamber (140); Alternatively, multiple sub-support elements (151) may be independently arranged, and at least some of the sub-support elements (151) may be fixedly connected to the pressure relief chamber (140).

5. The lower molded part according to claim 4, characterized in that, The support member (150) is configured in a wave shape, and the support member (150) includes a plurality of alternating peaks and troughs; the fitting part (153) is configured as a peak.

6. The lower molded part according to claim 4, characterized in that, At least some of the sub-support elements (151) are interconnected, and at least some of the sub-support elements (151) are independently arranged; At least a portion of the sub-support element (151) is fixedly connected to the pressure relief chamber (140).

7. The lower molded part according to any one of claims 1-6, characterized in that, At least a portion of the support member (150) has its projection on the plastic body (100) located within the projection of the explosion-proof valve on the plastic body (100).

8. The lower molded part according to any one of claims 2-6, characterized in that, The pressure relief chamber (140) has multiple through first slots (141). And / or, the support member (150) has a plurality of through second holes (152).

9. The lower molded part according to any one of claims 2-6, characterized in that, The plastic body (100) includes a first lower plastic component (110) and a second lower plastic component (120), and a gap (130) is provided between the first lower plastic component (110) and the second lower plastic component (120). The pressure relief chamber (140) is located on the first lower plastic part (110); And / or, the pressure relief chamber (140) is located on the second lower plastic part (120); And / or, the pressure relief cavity (140) is located between the first lower plastic part (110) and the second lower plastic part (120), and at least part of the gap (130) is located inside the pressure relief cavity (140).

10. A cover plate assembly, characterized in that, Includes a cover plate and the lower plastic part as described in any one of claims 1-9 above.

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