Battery cell cover plate and battery cell
By designing support bosses and folding sections to fix the tabs, the problem of easy damage to the tabs of lithium-ion battery covers under vibration or impact is solved, improving the reliability and safety of the battery cells and enhancing heat dissipation performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SVOLT ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2026-02-03
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional lithium-ion battery cover assemblies are prone to fatigue fracture or solder cracking under severe vibration or impact, resulting in a high risk of internal short circuits and a lack of effective fixation and protection.
A battery cell cover plate was designed, which includes a support boss and a mounting boss. The electrode tabs are fixed by a folding part and a fixing part. The support boss bears external force, increases the contact area for heat conduction and heat dissipation, and releases pressure through an explosion-proof valve and a vent.
It effectively avoids electrode fatigue fracture and solder cracking, improves the mechanical reliability and safety of the battery cell, enhances heat dissipation performance, reduces the risk of internal short circuits, and simplifies the maintenance process.
Smart Images
Figure CN122025946A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery technology, and more particularly to a cell cover and a cell. Background Technology
[0002] Lithium-ion batteries have become crucial components in power batteries, energy storage devices, and other fields due to their high energy density and long cycle life. As the smallest unit of a lithium-ion battery, the reliability and safety of its internal structure are of paramount importance.
[0003] Traditional cover plate assemblies typically only have simple internal insulation components for insulation between the electrode post and the cover plate body. The tabs at the top of the electrode assembly are directly bent and welded to the lower end of the electrode post. In this structure, the welded tabs and their solder areas are completely exposed, lacking effective fixation and protection. When the cell is subjected to severe vibration, impact, or other external forces, the internal electrode assembly will shift. This shifting will directly generate tensile stress at the bend of the tabs and the solder area, which can easily lead to fatigue fracture of the tabs or cracking of the solder, thereby causing an internal short circuit and posing a safety threat. Summary of the Invention
[0004] This invention provides a cell cover plate and a cell to solve the problems that occur when the cell is subjected to severe vibration, impact or other external forces, the internal electrode assembly will move around, which can easily lead to fatigue fracture of the electrode tabs or cracking of the solder.
[0005] This invention provides a battery cell cover plate, comprising: The cover plate body has a reference surface on one side, on which a support boss and a mounting boss are formed along the length direction of the cover plate body, and the support boss and the mounting boss protrude from the reference surface; The pole extends through the cover plate body, with its first end protruding from the reference surface. In the thickness direction of the cover plate body, the height of the support boss relative to the reference surface is greater than the height of the pole protruding from the reference surface. The second end of the pole is used to connect with the electrode tab. An insulating layer includes a fixing part and a folding part; the fixing part is disposed on the side of the cover plate body opposite to the cover plate body; the folding part is rotatably connected to the fixing part, and the insulating layer has an open state and a pressed state; in the open state, the folding part is separated from the electrode tab; in the pressed state, the folding part covers and presses against the electrode tab to fix the electrode tab and connect to the second end of the electrode post.
[0006] According to the present invention, a battery cell cover plate is provided, wherein the fixing part includes a first insulating layer, one of the first insulating layer and the cover plate body is provided with a slot, and the other is provided with a buckle. The first insulating layer is disposed on the side of the cover plate body away from the reference surface through the slot and the buckle. The first insulating layer is located at the position corresponding to the mounting boss, and the first insulating layer is provided with a groove suitable for avoiding the internal structure.
[0007] According to a battery cell cover provided by the present invention, the mounting boss is provided with a mounting groove, and the battery cell cover further includes: an explosion-proof valve disposed in the mounting groove; The mounting boss is provided with an exhaust notch communicating with the mounting groove; the first insulating layer is provided with a vent hole communicating with the mounting groove.
[0008] According to a battery cell cover plate provided by the present invention, the insulating layer further includes: a second insulating layer, the second insulating layer being disposed on the side of the cover plate body away from the reference surface, located at a position corresponding to the reference surface and the support boss.
[0009] According to a battery cell cover plate provided by the present invention, the bottom wall thickness of the groove of the first insulating layer is t, the side wall thickness of the groove is t1, the wall thickness of the folded portion is t2, 0.9mm≤t≤1.1mm, 0.9≤t1 / t≤1.3, and 0.6≤t2 / t1≤1.0.
[0010] According to the present invention, a battery cell cover plate is provided, wherein a plurality of vent holes are provided, the projected area of the first insulating layer along the projection surface perpendicular to the thickness direction of the cover plate body is S, and the total area of all the vent holes is S1, and 0.2≤S1 / S≤0.4.
[0011] According to the present invention, a battery cell cover plate is provided, wherein two pole posts are provided on the cover plate body, and two tabs are provided on the side of the cover plate body away from the reference surface. The second end of each pole post is used to connect to the corresponding tab. The distance between the two tabs along the length direction of the cover plate body is C. Two tab welding stations are provided on the pole posts along the width direction of the cover plate body. The distance between the outermost two tab welding stations along the width direction of the cover plate body is A. The width of the folded portion along the width direction of the cover plate body is B. 2mm≤(BA) / 2≤3.5mm, 2mm≤(CB) / 2≤4mm.
[0012] According to the present invention, a battery cell cover plate further includes: The first reinforcing rib is disposed on at least one side edge of the supporting boss and the mounting boss along the width direction of the cover plate body; The second reinforcing rib is disposed around the mounting boss corresponding to the explosion-proof valve.
[0013] According to a battery cell cover plate provided by the present invention, two supporting bosses are provided, and the two supporting bosses are located at both ends of the mounting boss along the length direction of the cover plate body; The support boss is provided with an adhesive application area; The cell cover plate further includes: structural adhesive, disposed in the adhesive application area; in the height direction along the cover plate body, the height of the structural adhesive relative to the reference surface is greater than the height of the mounting boss relative to the reference surface, so as to abut against the external structure through the structural adhesive.
[0014] The present invention also provides a battery cell, comprising: The battery cell casing has an opening; The aforementioned cell cover plate is disposed at the opening and surrounds the cell housing to form a receiving cavity; An electrode assembly is disposed within the receiving cavity, and the electrode tabs of the electrode assembly are connected to the electrode post.
[0015] The cell cover provided in this embodiment, by introducing a folding part and a fixing part, firmly fixes the tab to the second end of the terminal post. This effectively avoids the tensile stress on the bending point of the tab and the solder area caused by the internal electrode assembly movement when the battery is subjected to severe vibration or impact. This greatly reduces the risk of fatigue fracture of the tab or cracking of the solder, fundamentally improving the mechanical reliability and safety of the cell. At the same time, the folding part can be opened, providing a spacious and convenient working space for welding the tab to the terminal post, while the overall detachable feature of the fixing part greatly facilitates subsequent maintenance, inspection, or replacement.
[0016] Furthermore, because the height of the support boss relative to the reference plane is greater than the height of the terminal post protruding from the reference plane, in the battery module or battery pack, when the upper casing is subjected to external impact or compression, the support boss will contact the upper casing before the terminal post, becoming the main force-bearing and support component. This effectively avoids the terminal post directly bearing excessive external force, greatly reducing the risk of internal short circuits caused by deformation or damage to the terminal post. Moreover, the support boss and the mounting boss together form the raised structure on the outer side of the cover plate body, significantly increasing the effective contact area between the cover plate and the upper casing of the battery pack. This allows the heat generated by the cell during operation to be directly conducted to the upper casing for heat dissipation through the large-area boss structure, transforming some of the original heat radiation heat dissipation into more efficient heat conduction heat dissipation, significantly improving the heat dissipation performance of the cell. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in this invention 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 some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0018] Figure 1 This is a three-dimensional structural diagram of the battery cell cover plate provided by the present invention.
[0019] Figure 2 This is a three-dimensional structural diagram of the back of the battery cell cover provided by the present invention.
[0020] Figure 3 This is one of the disassembly diagrams of the battery cell cover plate provided by the present invention.
[0021] Figure 4 This is the second disassembly diagram of the battery cell cover provided by the present invention.
[0022] Figure 5 This is one of the schematic diagrams showing the connection between the cell cover plate and the electrode assembly provided by the present invention.
[0023] Figure 6 This is an enlarged schematic diagram of the connection between the cell cover plate and the electrode assembly provided by the present invention.
[0024] Figure 7 This is the second schematic diagram of the connection between the cell cover plate and the electrode assembly provided by the present invention.
[0025] Figure 8 This is a schematic diagram of the battery cell provided by the present invention.
[0026] Figure label: 1. Cell cover plate; 11. Cover plate body; 111. Reference surface; 112. Support boss; 113. Mounting boss; 114. Slot; 12. First reinforcing rib; 121. First venting notch; 13. Second reinforcing rib; 131. Second venting notch; 14. Insulation layer; 141. Fixing part; 1411. First insulation layer; 1412. Second insulation layer; 1413. Buckle; 142. Folding part; 15. Explosion-proof valve; 16. Terminal post; 17. Connecting piece; 171. Terminal lug welding station; 18. Riveting block; 19. Applying plastic; 2. Cell casing; 3. Electrode assembly; 31. Electrode tab. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0028] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "first" and "second" are numbered for the purpose of clearly identifying product components and do not represent any substantial difference. The terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances. Furthermore, "multiple" means two or more. In the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following related objects are in an "or" relationship.
[0029] In some embodiments, such as Figures 1 to 6 As shown, the cell cover plate 1 includes: a cover plate body 11, a terminal post 16, and an insulating layer 14. One side of the cover plate body 11 has a reference surface 111, on which a support boss 112 and a mounting boss 113 are formed along the length direction of the cover plate body 11. The support boss 112 and the mounting boss 113 protrude from the reference surface 111. The terminal post 16 penetrates the cover plate body 11, and the first end of the terminal post 16 protrudes from the reference surface 111. In the thickness direction of the cover plate body 11, the height of the support boss 112 relative to the reference surface 111 is greater than the height of the terminal post 16 protruding from the reference surface 111. The second end of the terminal post 16 is used to connect with the tab 31.
[0030] See Figure 1 The cover plate body 11 has a length direction (x-axis) and a width direction (y-axis), and the thickness direction (z-axis) of the cover plate is perpendicular to the length and width directions and perpendicular to the reference surface 111. One side (generally the upper side) of the cover plate body 11 is defined as a flat reference surface 111. On this reference surface 111, support bosses 112 and mounting bosses 113 are integrally formed along the length direction of the cover plate body 11 through processes such as stamping.
[0031] In this embodiment, the insulating layer 14 includes a fixing part 141 and a folding part 142. The fixing part 141 is detachably disposed on the side of the cover plate body 11 away from the cover plate body 11. The folding part 142 is rotatably connected to the fixing part 141. The insulating layer 14 has an open state and a pressed state. In the open state, the folding part 142 is separated from the electrode tab 31. In the pressed state, the folding part 142 covers and presses against the electrode tab 31 to fix the electrode tab 31 and connect to the second end of the electrode post 16.
[0032] Specifically, during the cell assembly and welding stage, the operator first rotates the folding part 142 upwards, opening it up. At this time, a wide angle is formed between the folding part 142 and the fixing part 141 (generally, the folding part 142 is perpendicular to the cover plate body 11). The tab 31 at the top of the electrode group 3 is guided to the welding position below the pole post 16. Since the folding part 142 is fully open, welding tools (such as laser welding heads) can approach without obstruction and perform precise welding at the connection between the tab 31 and the pole post 16, ensuring a smooth welding process and reliable weld quality.
[0033] After welding is completed, the operator rotates the folding part 142 downwards, switching it from the open state to the pressed state. In this state, the folding part 142 rotates to a horizontal position, acting like a protective cover over the bent portion of the tab 31 and the weld mark formed between it and the pole post 16. The folding part 142 applies a controllable downward clamping force to the tab 31, which firmly presses the tab 31 onto the end face of the pole post 16.
[0034] Throughout the entire lifespan of the battery cell, it can remain in a pressed state. This ensures that the connection point between the tab 31 and the terminal 16 is always in a protected and fixed environment, which not only improves the mechanical stability of the welding point but also enhances the long-term reliability of the battery cell under harsh operating conditions.
[0035] The cell cover 1 provided in this embodiment, by introducing a folding part 142 and a fixing part 141, firmly fixes the tab 31 to the second end of the terminal post 16, thereby effectively avoiding the tensile stress on the bending point and solder area of the tab 31 caused by the internal electrode assembly 3 shifting when the battery is subjected to severe vibration or impact. This greatly reduces the risk of fatigue fracture of the tab 31 or cracking of the solder, fundamentally improving the mechanical reliability and safety of the cell. At the same time, the folding part 142 can be folded open, providing a spacious and convenient working space for welding the tab 31 to the terminal post 16, while the overall detachable feature of the fixing part 141 greatly facilitates subsequent maintenance, inspection or replacement.
[0036] Furthermore, since the height of the support boss 112 relative to the reference surface 111 is greater than the height of the terminal post 16 protruding from the reference surface 111, in the battery module or battery pack, when the upper casing is subjected to external impact or compression, the support boss 112 will contact the upper casing before the terminal post 16, becoming the main force-bearing and support component. This effectively avoids the terminal post 16 directly bearing excessive external force, greatly reducing the risk of internal short circuits caused by deformation or damage to the terminal post 16 under stress. Moreover, the support boss 112 and the mounting boss 113 together constitute the raised structure on the outer side of the cover plate body 11, significantly increasing the effective contact area between the cover plate and the upper casing of the battery pack. This allows the heat generated by the cell during operation to be directly conducted to the upper casing for heat dissipation through the large-area boss structure, transforming some of the original heat radiation heat dissipation into more efficient heat conduction heat dissipation, significantly improving the heat dissipation performance of the cell.
[0037] In some embodiments, such as Figures 2 to 6 As shown, the insulating layer 14 is a lower plastic layer, which is tightly disposed on the side of the cover plate body 11 facing the inside of the battery cell. Its function is to achieve reliable electrical isolation between the charged body such as the pole post 16 and the aluminum cover plate body 11, and to prevent internal short circuits.
[0038] Meanwhile, the battery cell cover plate 1 has an upper plastic 19 on one side with a reference surface 111. The reference surface 111 is generally provided with a positioning groove. The upper plastic 19 is set in the positioning groove. The two ends of the pole post 16 are provided with the upper plastic 19, the cover plate body 11 and the lower plastic. A riveting block 18 connected to the pole post 16 can be set in the upper plastic 19.
[0039] In some embodiments, such as Figures 2 to 6 As shown, the fixing part 141 includes a first insulating layer 1411. One of the first insulating layer 1411 and the cover plate body 11 is provided with a slot 114, and the other is provided with a buckle 1413. The first insulating layer 1411 is detachably disposed on the side of the cover plate body 11 away from the reference surface 111 through the slot 114 and the buckle 1413. The first insulating layer 1411 is located at the position corresponding to the mounting boss 113. The first insulating layer 1411 is provided with a groove suitable for avoiding the internal structure, thereby increasing the space inside the cell.
[0040] Specifically, the first insulating layer 1411 is provided with a snap fastener 1413, and the back of the cover plate body 11 is provided with a slot 114. By aligning the snap fastener 1413 and inserting it into the slot 114, the connection between the first insulating layer 1411 and the side of the cover plate body 11 facing away from the reference surface 111 can be achieved. This snap fastener 1413 connection not only eliminates the need for additional fasteners, simplifies the assembly process, and improves production efficiency, but more importantly, it makes it extremely convenient to inspect or replace the insulating component in subsequent processes.
[0041] The mounting position of the first insulating layer 1411 corresponds to the mounting boss 113 on the reference surface 111 of the cover plate body 11. The projection of the first insulating layer 1411 on the inner side of the cover plate roughly coincides with the mounting boss 113, thereby facilitating the placement of the first insulating layer 1411 and increasing the internal space of the battery cell.
[0042] To further optimize the utilization of the limited space inside the battery cell, such as Figure 7 As shown, the first insulating layer 1411 has a groove on the side facing the internal electrode group 3 of the cell (i.e., the side facing away from the cover plate body 11). This groove is designed to provide dedicated space for other components inside the cell, such as the protrusions on the electrode group 3. This embedded method effectively avoids structural interference between the first insulating layer 1411 and the internal components, allowing the cell to provide a larger volume space within the same external dimensions, or to achieve miniaturization and flattening of the overall cell thickness while maintaining a given capacity, directly improving the energy density and structural compactness of the cell.
[0043] In some embodiments, such as Figures 1 to 4 As shown, the mounting boss 113 has a mounting groove, and the cell cover plate 1 also includes an explosion-proof valve 15. The explosion-proof valve 15 is disposed in the mounting groove. The mounting boss 113 has an exhaust notch communicating with the mounting groove, and the first insulating layer 1411 has a vent hole communicating with the mounting groove.
[0044] In this embodiment, the mounting boss 113 has a recessed mounting groove machined on its top platform (i.e., the surface protruding from the reference surface 111). This mounting groove is used to accommodate and fix the explosion-proof valve 15. The explosion-proof valve 15 is typically a thin sheet-like metal valve body, the edges of which are sealed and fixed to the bottom or side wall of the mounting groove by processes such as laser welding, riveting, or bonding. The cell cover plate 1 also includes a connecting piece 17. The connecting piece 17 is disposed on the side of the cover plate body 11 facing away from the reference surface 111, one end of the connecting piece 17 is connected to the second end of the pole post 16, and the other end of the connecting piece 17 extends to connect with the tab 31.
[0045] To achieve directional pressure release, one or more venting notches are provided on the side wall of the mounting boss 113. Each venting notch is an opening or groove penetrating the side wall of the mounting boss 113, with its lower end communicating with the internal space of the mounting groove. When the explosion-proof valve 15 ruptures or opens due to excessive internal pressure in the battery cell, the resulting high-temperature, high-pressure gas will first rush into the mounting groove where it is located.
[0046] To effectively guide the internal pressure of the battery cell to the explosion-proof valve 15, a vent hole is correspondingly provided on the first insulating layer 1411 located on the inner side of the cover plate. This vent hole is a hole that penetrates the first insulating layer 1411. The vent hole ensures that the gas passage between the internal space of the battery cell and the cavity where the explosion-proof valve 15 is located is unobstructed.
[0047] When a battery cell experiences thermal runaway or other abnormal conditions, internal gas production causes a rapid increase in pressure. The high-pressure gas passes through the vents in the first insulation layer 1411 and rapidly acts on the back of the explosion-proof valve 15. When the pressure exceeds the preset burst pressure threshold of the explosion-proof valve 15, the valve body ruptures or deforms at the mounting groove, opening the valve. The high-pressure gas instantly bursts through the explosion-proof valve 15, enters the mounting groove space, and is then discharged laterally rather than directly upwards into the external environment of the battery cell through the vent on the side wall of the mounting boss 113.
[0048] Generally, multiple vent holes are provided. These holes are not evenly distributed, but are concentrated in the area below the mounting groove of the corresponding explosion-proof valve 15 to form a pressure relief channel. To achieve the optimal balance between pressure relief efficiency and the structural strength of the insulating components, the projected area of the first insulating layer 1411 along the direction perpendicular to the thickness of the cover plate body 11 is S, and the total opening area of all vent holes is S1. The ratio of the two satisfies: 0.2≤S1 / S≤0.4.
[0049] When a battery cell experiences thermal runaway or other abnormal conditions, resulting in a large amount of gas being generated internally and causing a sudden pressure surge, the gas needs to be quickly directed to the explosion-proof valve 15. The total area (S1) of the vent holes is controlled to be no less than 20% of the total area (projected area S) of the first insulation layer 1411 (i.e., S1 / S ≥ 0.2), ensuring that the pressure relief channel has a sufficiently large flow cross-sectional area. This effectively avoids poor gas discharge due to narrow channels and excessive resistance, preventing pressure buildup and delays inside the battery cell, thereby ensuring that the explosion-proof valve 15 can open promptly and accurately at the set pressure threshold.
[0050] On the other hand, setting the upper limit of the total area of the vent holes to 40% of the total area of the first insulation layer 1411 (i.e., S1 / S ≤ 0.4) is for the protection of the mechanical strength and integrity of the first insulation layer 1411. The first insulation layer 1411 is not only a pressure transmission path, but also a crucial insulation barrier between the pole post 16 and the cover plate body 11. If the opening area on the insulation layer 14 is too large, it will excessively weaken its structural rigidity, making it prone to deformation or even breakage when subjected to normal pressure fluctuations inside the cell, assembly stress, or external vibration. Once the structure of the first insulation layer 1411 fails, it will directly lead to the loss of insulation function and cause a short circuit.
[0051] like Figure 3 and Figure 4 As shown, the insulating layer 14 further includes a second insulating layer 1412. The second insulating layer 1412 is also detachably disposed on the side of the cover body 11 facing away from the reference surface 111, for example, via a snap-fit 1413 or a positioning post. The second insulating layer 1412 is located corresponding to the reference surface 111 and the support boss 112. Its main function is to eliminate any potential risk of electrical short circuits between these large-area metal structural areas and internal components.
[0052] In this embodiment, two second insulating layers 1412 are typically provided. These two second insulating layers 1412 are located on both sides of the cover plate body 11 along its length, while the first insulating layer 1411 is disposed precisely between the two second insulating layers 1412, forming a clear three-segment structure of the second insulating layer 1412, the first insulating layer 1411, and the second insulating layer 1412.
[0053] The central area where the first insulating layer 1411 is located typically needs to accommodate the explosion-proof valve 15, while the second insulating layers 1412 on both sides mainly house the pole posts 16 and the tabs 31, etc. Decomposing a large insulating component into three independent, smaller modules reduces the manufacturing precision requirements and assembly difficulty for each part. If a part (such as the central first insulating layer 1411) needs to be replaced due to long-term use or accident, it is not necessary to replace the entire insulating component; only the module needs to be disassembled, reducing maintenance costs.
[0054] In some embodiments, such as Figures 1 to 3 As shown, the bottom wall thickness of the groove of the first insulating layer 1411 is t, 0.9mm ≤ t ≤ 1.1mm. This parameter t defines the thickness of the bottom (thinnest part) of the groove of the first insulating layer 1411. It is strictly controlled between 0.9mm and 1.1mm. The lower limit (0.9mm) ensures that this area has sufficient electrical insulation strength to reliably withstand the working voltage and possible transient overvoltage inside the cell, avoiding the risk of breakdown. At the same time, this thickness also provides the necessary structural rigidity to prevent collapse or deformation under pressure or vibration. The upper limit (1.1mm) avoids excessive material accumulation, helps control component weight and cost, and ensures that the groove has an effective spatial accommodating depth.
[0055] The sidewall thickness of the groove is t1, where 0.9 ≤ t1 / t ≤ 1.3. The sidewall thickness can be approximately equal to the bottom thickness of the groove (ratio ≈ 1), or slightly thinner (ratio ≥ 0.9) to optimize space, or slightly thicker (ratio ≤ 1.3). The main purpose is to ensure the uniformity of the overall groove structure and the stability of the mold injection process. This avoids uneven cooling and shrinkage due to excessive wall thickness differences, which can lead to defects such as internal stress, shrinkage marks, or even cracking.
[0056] The wall thickness of the folded portion 142 is t2, where 0.6 ≤ t2 / t1 ≤ 1.0. This ratio makes the folded portion 142 thinner than the first insulating layer 1411. The thinner wall thickness ensures that the folded portion 142 has moderate flexibility, resulting in a more reasonable stress distribution at the hinge during repeated folding and rotation, making it less prone to fatigue breakage and thus improving its service life. At the same time, this thickness is sufficient to provide the necessary rigidity, allowing the folded portion 142 to stably maintain its shape in the pressed state and apply a uniform and sustained clamping force to the tab 31, effectively fixing the tab 31 while avoiding damage to the solder joint due to excessive hardness.
[0057] In some embodiments, such as Figure 1 , Figure 5 and Figure 6 As shown, two pole posts 16 are provided on the cover plate body 11, and two tabs 31 are provided on the side of the cover plate body 11 away from the reference surface 111. The second end of each pole post 16 is used to connect to the corresponding tab 31. The distance between the two tabs 31 along the length direction of the cover plate body 11 is C. Two tab welding stations 171 (or two tab welding stations 171 provided on the connecting piece 17) are provided on the pole post 16 along the width direction of the cover plate body 11. The distance between the outermost two tab welding stations 171 along the width direction of the cover plate body 11 is A. The width of the folded part 142 along the width direction of the cover plate body 11 is B. 2mm≤(BA) / 2≤3.5mm, 2mm≤(CB) / 2≤4mm.
[0058] In this embodiment, each pole post 16 is provided with two electrode tab welding stations 171 arranged along the width direction of the cover plate body 11. The distance between the outermost edges of these two stations in the width direction is defined as A. The folded portion 142 covering the electrode tab 31 assembly has a width defined as B along the width direction of the cover plate body 11.
[0059] The width B of the folded portion 142 is greater than the width A of the welding station, and its single-sided excess (i.e., (BA) / 2) is strictly controlled between 2 mm and 3.5 mm. This ensures that when the folded portion 142 is in the pressed state, it can completely cover the entire welding station area (width A) and effectively press the tab 31. The lower limit of 2 mm ensures that even with minor assembly or manufacturing tolerances, the folded portion 142 will never have insufficient coverage, resulting in the exposure of the edge of the tab 31; while the upper limit of 3.5 mm avoids the folded portion 142 being designed too wide, causing material waste, increased space occupation, and possible interference with adjacent components (such as the assembly of another pole post 16).
[0060] The spacing C between the two tabs 31 is greater than the width B of a single folded portion 142, with the single-sided gap (i.e., (CB) / 2) controlled between 2 mm and 4 mm. This gap effectively prevents electrical creep or momentary arcing due to excessive proximity, eliminating the risk of internal short circuits. The lower limit of 2 mm is set based on the minimum safe distance requirements of electrical insulation standards; while the upper limit of 4 mm prevents an unnecessary increase in the overall size of the cover plate due to excessive spacing, optimizing space utilization and ensuring the energy density of the battery cell.
[0061] In some embodiments, such as Figure 1 As shown, the total length of the cover plate body 11 along its length direction is L, 150≤L≤300, and the total width of the cover plate body 11 along its width direction is W, 25≤W≤75.
[0062] In this embodiment, the cell cover plate 1 further includes: a first reinforcing rib 12 and a second reinforcing rib 13. The first reinforcing rib 12 is disposed on at least one side edge of the supporting boss 112 and the mounting boss 113 along the width direction of the cover plate body 11; the second reinforcing rib 13 is disposed around the mounting boss 113 corresponding to the explosion-proof valve 15.
[0063] There are two supporting bosses 112, and a mounting boss 113 is located between these two supporting bosses 112, thus forming a continuous boss array of "supporting boss 112 - mounting boss 113 - supporting boss 112" along the length of the cover plate body 11. The reinforcing ribs include two first reinforcing ribs 12, which are respectively and continuously disposed on the two outer edges of the aforementioned boss array along the width direction of the cover plate body 11.
[0064] Each first reinforcing rib 12 starts from the side edge of the supporting boss 112 at one end, extends continuously through the corresponding side edge of the mounting boss 113, and finally reaches the side edge of the supporting boss 112 at the other end, thus forming a continuous reinforcing frame between the two bosses. The continuously extending first reinforcing ribs 12 structurally connect the originally independent supporting bosses 112 and mounting bosses 113 into a whole, greatly enhancing the overall rigidity and bending resistance of the cover plate in the length direction. When the cell cover plate 1 is subjected to external loads, the reinforcing rib can effectively transfer and disperse the stress smoothly along its length direction, avoiding stress concentration at the boss connection, and improving the impact resistance and fatigue resistance of the cell cover plate 1.
[0065] The second reinforcing rib 13 is disposed around the periphery of the mounting boss 113 corresponding to the explosion-proof valve 15. This second reinforcing rib 13 can be a closed annular frame structure, or it can be composed of several discrete rib segments distributed on both sides or around the explosion-proof valve 15. Its function is to provide localized reinforcement to the mounting area of the explosion-proof valve 15 from the side. The second reinforcing rib 13 can provide effective support and protection for the explosion-proof valve 15 and the local area of the mounting boss 113. When subjected to external compression or internal pressure impact, the second reinforcing rib 13 can significantly enhance the deformation resistance of the mounting boss 113, preventing the collapse or warping of the mounting boss 113 from adversely affecting the welding sealing and operational accuracy of the explosion-proof valve 15, thereby ensuring that the explosion-proof valve 15 is reliably triggered under predetermined operating conditions.
[0066] To further optimize the pressure relief function, a dedicated venting notch is designed into the structure. Specifically, a first venting notch 121 is stamped or machined on the first reinforcing rib 12, and correspondingly, there is no second venting notch 131 on the second reinforcing rib 13 at the position corresponding to the first venting notch 121. The first venting notch 121 and the second venting notch 131 are aligned in the horizontal direction, forming a gas venting channel. When thermal runaway occurs in the battery cell, the high-temperature gas inside can be discharged from the explosion-proof valve 15. The high-temperature and high-pressure gas flow can first escape rapidly from the mounting boss 113 area through the second venting notch 131, and then be guided to the edge through the first venting notch 121.
[0067] In some embodiments, such as Figures 1 to 6 As shown, there are two support bosses 112. These two support bosses 112 are not isolated but are located at opposite ends of the mounting boss 113 along the length of the cover plate body 11. Each support boss 112 has a top surface with an adhesive application area. The cell cover plate 1 also includes structural adhesive, which is applied to the adhesive application area. After curing, the final height of the structural adhesive relative to the reference surface 111 along the height direction of the cover plate body 11 is controlled to be greater than the height of the top surface of the mounting boss 113 relative to the reference surface 111, so that it abuts against the external structure through the structural adhesive and reinforcing ribs.
[0068] When the cell cover 1 is assembled with the upper casing and other external structures, the upper casing will first contact and press against the upper surface of the structural adhesive due to the maximum height of the structural adhesive. This allows external loads (such as compression and vibration impact) to be preferentially transferred through the buffering structural adhesive to the mechanically strong support boss 112 and its continuous reinforcing rib network, and finally distributed throughout the entire cover body 11. This bypasses the relatively fragile mounting boss 113 and its explosion-proof valve 15, as well as the reference surface 111 area where the pole post 16 is welded, thus protecting critical safety components.
[0069] Meanwhile, the top surface of the supporting boss 112, the top surface of the reinforcing ribs thereon, and the structural adhesive filling them together constitute an effective heat transfer interface. The heat generated by the battery cell can be efficiently conducted to the upper casing with extremely low thermal resistance through this interface, where the upper casing acts as a heat sink to dissipate the heat. This significantly improves the heat dissipation capacity of the battery pack.
[0070] like Figure 8 As shown, this embodiment of the invention also provides a battery cell, including: a battery cell housing 2, a battery cell cover plate 1, and the battery cell cover plate 1 of any of the above embodiments.
[0071] In this embodiment, the cell housing 2 is typically a hollow structure made of metal materials such as aluminum, aluminum alloy, or stainless steel, with an opening at one end to accommodate the electrode assembly 3 and the electrolyte. The cell cover plate 1 is sealed by welding (e.g., laser welding) to the edge of the opening in the cell housing 2, thereby closing the opening and forming a sealed cavity together with the cell housing 2. The tabs 31 on the electrode assembly 3 are electrically connected to the corresponding terminals 16 within the cavity.
[0072] In one specific embodiment, as shown in Table 1 below, the bottom wall thickness of the groove of the first insulating layer 1411 is t1, the side wall thickness of the groove is t1, the wall thickness of the folded part 142 is t2, the total area of the first insulating layer 1411 is S, the total area of all vent holes is S1, the distance between the two tabs 31 along the length of the cover plate body 11 is C; the pole post 16 is provided with two tab welding stations 171 arranged along the width of the cover plate body 11, the distance between the outermost of the two tab welding stations 171 is A, and the width of the folded part 142 along the width of the cover plate body 11 is B.
[0073] Table 1 T (mm) t1 (mm) t2 (mm) <![CDATA[S(mm 2 )]]> <![CDATA[S1(mm 2 )]]> A (mm) B (mm) C (mm) t1 / t t2 / t1 S1 / S (BA) / 2 (mm) (CB) / 2 (mm) Example 1 0.9 1.15 1.1 2533 984 13.5 19 25 1.28 0.96 0.39 2.8 3.0 Example 2 0.9 1.1 0.95 2533 1013 13.5 18 26 1.22 0.86 0.40 2.3 4.0 Example 3 0.95 1 0.9 2533 918 14.8 19 27 1.05 0.90 0.36 2.1 4.0 Example 4 0.96 1.15 0.85 2610 785 14.8 21 28 1.20 0.74 0.30 3.1 3.5 Example 5 1 1.1 0.8 2610 660 14.8 20 26.5 1.10 0.73 0.25 2.6 3.3 Example 6 1 1.15 0.75 2610 510 15.9 21 25 1.15 0.65 0.20 2.6 2.0 Example 7 1.05 1.2 0.75 2876 705 15.9 20 24.5 1.14 0.63 0.25 2.1 2.3 Example 8 1.05 1.15 0.9 2876 595 15.9 22 27 1.10 0.78 0.21 3.1 2.5 Example 9 1.1 1 0.98 2876 857 15.9 22.5 28 0.91 0.98 0.30 3.3 2.8 Comparative Example 1 0.85 1.1 0.95 2533 1083 13.5 18 26 1.29 0.86 0.43 2.3 4.0 Comparative Example 2 1.1 0.9 0.9 2876 857 15.9 22.5 28 0.82 1.00 0.30 3.3 2.8 Comparative Example 3 1 1.15 0.75 2610 510 15.9 21 24 1.15 0.65 0.20 2.6 1.5 By comparing and analyzing the test data of nine embodiments and three comparative examples, the scientific validity of the design range of various key dimensional parameters was fully verified. The parameters of all embodiments, such as the bottom wall thickness t, the side wall thickness ratio t1 / t, the folded section wall thickness ratio t2 / t1, the pressure relief area ratio S1 / S, the protection margin (BA) / 2, and the safety clearance (CB) / 2, all fall within or are very close to the preset ideal range. The corresponding test results consistently show that: "The cover assembly is normal, the strength of the lower plastic structure meets the requirements, and after cell assembly, CT inspection shows that the lower plastic folded section covers the electrode tab solder marks, and there is a certain safety clearance between the folded section and the electrode group." This indicates that when the parameters are within this optimized range, the cell cover assembly can perfectly balance manufacturability, structural integrity, effective electrode tab protection, and internal safety insulation.
[0074] In contrast, the three comparative examples revealed clear problems because certain parameters exceeded the recommended range: Comparative Example 1: Its tank bottom wall thickness t = 0.85 mm, slightly lower than the recommended lower limit of 0.9 mm, while the pressure relief area ratio S1 / S = 0.43 exceeds the upper limit of 0.4. This results in "structural strength deviation and deformation problems" in the lower plastic layer. This confirms that the minimum value of t is important for ensuring the rigidity of the foundation, and the maximum value of S1 / S is important for maintaining the overall structural strength of the insulation layer.
[0075] Comparative Example 2: Its sidewall thickness ratio t1 / t = 0.82, which is lower than the recommended lower limit of 0.9. The result also showed structural strength deviation and deformation problems. This indicates that maintaining an appropriate thickness ratio between the sidewall and the bottom of the tank (t1 / t ≥ 0.9) is essential to avoid local weakening and structural instability caused by uneven wall thickness.
[0076] Comparative Example 3: Its safety clearance (CB) / 2 = 1.5mm, which is lower than the recommended lower limit of 2mm. As a result, the gap between the folded part and the tab is too small, and there is a risk of damaging the tab when the cell is subjected to external force. This strongly proves that ensuring a sufficient safety clearance ((CB) / 2≥2mm) is a rigid requirement to prevent component interference under dynamic operating conditions and to ensure the long-term safety of the tab.
[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A battery cell cover plate, characterized in that, include: The cover plate body has a reference surface on one side, on which a support boss and a mounting boss are formed along the length direction of the cover plate body, and the support boss and the mounting boss protrude from the reference surface; The pole extends through the cover plate body, with its first end protruding from the reference surface. In the thickness direction of the cover plate body, the height of the support boss relative to the reference surface is greater than the height of the pole protruding from the reference surface. The second end of the pole is used to connect with the electrode tab. An insulating layer includes a fixing part and a folding part; the fixing part is disposed on the side of the cover plate body opposite to the cover plate body; the folding part is rotatably connected to the fixing part, and the insulating layer has an open state and a pressed state; in the open state, the folding part is separated from the electrode tab; in the pressed state, the folding part covers and presses against the electrode tab to fix the electrode tab and connect to the second end of the electrode post.
2. The cell cover plate according to claim 1, characterized in that, The fixing part includes a first insulating layer. One of the first insulating layer and the cover plate body is provided with a slot, and the other is provided with a buckle. The first insulating layer is disposed on the side of the cover plate body away from the reference surface through the slot and the buckle. The first insulating layer is located at the position corresponding to the mounting boss. The first insulating layer is provided with a groove suitable for avoiding the internal structure.
3. The cell cover plate according to claim 2, characterized in that, The mounting boss is provided with a mounting groove, and the battery cell cover plate further includes an explosion-proof valve, which is disposed in the mounting groove; The mounting boss is provided with an exhaust notch communicating with the mounting groove; the first insulating layer is provided with a vent hole communicating with the mounting groove.
4. The cell cover plate according to claim 3, characterized in that, The insulating layer further includes a second insulating layer, which is disposed on the side of the cover plate body away from the reference surface and located at a position corresponding to the reference surface and the support boss.
5. The cell cover plate according to claim 4, characterized in that, The groove bottom wall thickness of the first insulating layer is t, the side wall thickness of the groove is t1, and the wall thickness of the folded part is t2. 0.9mm≤t≤1.1mm, 0.9≤t1 / t≤1.3, 0.6≤t2 / t1≤1.
0.
6. The cell cover plate according to claim 3, characterized in that, The ventilation holes are provided in multiple ways. The projected area of the first insulating layer along the direction perpendicular to the thickness of the cover plate body is S. The total area of all the ventilation holes is S1, and 0.2≤S1 / S≤0.
4.
7. The cell cover plate according to claim 1, characterized in that, Two pole posts are provided on the cover plate body, and two tabs are provided on the side of the cover plate body away from the reference surface. The second end of each pole post is used to connect to the corresponding tab. The distance between the two tabs along the length direction of the cover plate body is C. Two tab welding stations are provided on the pole posts along the width direction of the cover plate body. The distance between the outermost two tab welding stations along the width direction of the cover plate body is A. The width of the folded part along the width direction of the cover plate body is B. 2mm≤(BA) / 2≤3.5mm, 2mm≤(CB) / 2≤4mm.
8. The cell cover plate according to claim 4, characterized in that, The cell cover plate also includes: The first reinforcing rib is disposed on at least one side edge of the supporting boss and the mounting boss along the width direction of the cover plate body; The second reinforcing rib is disposed around the mounting boss corresponding to the explosion-proof valve.
9. The cell cover plate according to any one of claims 1-8, characterized in that, The support boss is provided in two parts, and the two support bosses are located at both ends of the mounting boss along the length direction of the cover plate body; The support boss is provided with an adhesive application area; The cell cover plate further includes: structural adhesive, disposed in the adhesive application area; in the height direction along the cover plate body, the height of the structural adhesive relative to the reference surface is greater than the height of the mounting boss relative to the reference surface, so as to abut against the external structure through the structural adhesive.
10. A battery cell, characterized in that, include: The battery cell casing has an opening; The cell cover plate as described in any one of claims 1 to 9, wherein the cell cover plate is disposed at the opening and surrounds the cell housing to form a receiving cavity; An electrode assembly is disposed within the receiving cavity, and the electrode tabs of the electrode assembly are connected to the electrode post.