Blade battery cell cover plate structure and battery cell

Abstract

The invention relates to the technical field of lithium batteries, in particular to a blade cell cover plate structure and a cell, the blade cell cover plate structure comprises a shell and a cover plate assembly, the cover plate assembly is connected with the shell, the cover plate assembly comprises a metal base, a pole bottom plate, a first plastic part and a second plastic part, the metal base is connected with the shell, and the pole bottom plate is connected with the shell. The first plastic part is arranged on one surface of the metal base, the second plastic part is arranged on the other surface of the metal base, and the first plastic part is positioned in the shell; a mounting groove is formed in the first plastic part, the pole bottom plate is arranged in the mounting groove, and a surrounding gap is formed between the outer contour surface of the pole bottom plate and the inner wall surface of the mounting groove; and at least one circulation opening is formed in one side wall of the mounting groove. The circulation opening is formed in one side wall of the mounting groove, so that the circulation opening can be communicated with the surrounding gap, electrolyte in the space around the pole bottom plate can be discharged in time, and the situation that the electrolyte is accumulated for a long time, so that the overall safety performance of a battery cell is affected is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a blade battery cell cover plate structure and a battery cell. Background Art

[0002] Lithium-ion batteries are widely used in various industries due to their large capacity, high operating voltage, strong charge retention, and long cycle life. The cell is the smallest unit of a lithium-ion battery pack and generally consists of an electrode assembly, electrolyte, a bare cell insulation sheet, a cover (typically integrating electrodes, injection ports, and explosion-proof valves), and a casing. During connection, the cover securely connects to the casing and creates a sealed space for the electrode assembly.

[0003] The cover generally includes a pole, a bare aluminum sheet, upper plastic, lower plastic, and a sealing ring. In related technologies, in a blade cell battery pack, the cells are generally placed sideways with the cover placed upright. Electrolyte often accumulates in the gap between the pole base and the lower plastic rib of the cover. Over time, the electrolyte reacts with lithium ions to produce lithium dendrites. Over time, the lithium dendrites gradually grow outward along the gap between the pole base and the lower plastic rib, eventually causing a short circuit between the pole base and the bare aluminum sheet or the shell, resulting in a safety failure. Summary of the Invention

[0004] The present invention provides a blade cell cover plate structure and a cell, which are used to solve the defect in the prior art that electrolyte at the bottom plate position of the pole is difficult to discharge, thereby affecting the overall safety performance of the cell.

[0005] A first aspect of the present invention provides a blade battery cover structure, comprising: a shell and a cover assembly, the cover assembly being connected to the shell, and part of the structure of the cover assembly being located inside the shell; the cover assembly comprising a metal base, a pole bottom plate, a first plastic part and a second plastic part, the metal base being connected to the shell, the first plastic part being arranged on one surface of the metal base, the second plastic part being arranged on the other surface of the metal base, and the first plastic part being located inside the shell; a mounting groove is formed in the first plastic part, the pole bottom plate being arranged in the mounting groove, and a surrounding gap is provided between the outer contour surface of the pole bottom plate and the inner wall surface of the mounting groove; wherein, the mounting groove is provided with at least one flow opening on a side wall in the width direction of the first plastic part, and the flow opening is connected to the surrounding gap.

[0006] According to the blade cell cover structure provided by the present invention, a pole body with a columnar structure is provided on the pole bottom plate, and the pole body is passed through the first plastic part and the metal base, and is passed through the second plastic part; wherein, an insulating sealing sleeve is provided on the outer sleeve of the pole body, and the metal base and the second plastic part are both interference fit with the insulating sealing sleeve.

[0007] According to the blade battery cover structure provided by the present invention, the insulating sealing sleeve includes a main body and an annular limiting portion, the annular limiting portion is arranged at one end of the main body, and the outer diameter of the annular limiting portion is larger than the outer diameter of the main body; wherein, a first annular interference portion is formed between the annular limiting portion and the metal base, and a second annular interference portion is formed between the main body and the second plastic part.

[0008] According to the blade battery cover structure provided by the present invention, concentrically arranged connecting holes are provided on the first plastic part, the metal base and the second plastic part, the pole body is arranged in the connecting hole, and an installation gap is formed between the pole body and the connecting hole; wherein, the installation gap is 0.7-1.0mm, the insulating sealing sleeve is located in the installation gap, and the filling ratio between the insulating sealing sleeve and the installation gap is greater than 90%.

[0009] According to the blade battery cover structure provided by the present invention, the axial interference of the first annular interference portion in its own axial direction is 0.2-0.5mm, and the radial interference of the first annular interference portion in its own radial direction is 0.4-0.5mm; the interference of the second annular interference portion in its own axial direction is 0.4-0.5mm, and the radial interference of the second annular interference portion in its own radial direction is 0.8-1.1mm.

[0010] According to the blade battery cover structure provided by the present invention, the first plastic part, the metal base and the second plastic part are concentrically provided with connecting holes, the pole body is arranged in the connecting hole, and an installation gap is formed between the pole body and the connecting hole; wherein, the installation gap is 0.7-1.0mm, the insulating sealing sleeve is located in the installation gap, and the filling ratio between the insulating sealing sleeve and the installation gap is 80%-95%.

[0011] According to the blade cell cover structure provided by the present invention, the distances between the two side walls of the pole bottom plate in the width direction and the inner wall surface of the shell on each side in the width direction are both 1.5-5 mm.

[0012] According to the blade cell cover structure provided by the present invention, the first plastic part includes a first side wall and a second side wall arranged opposite to each other in the width direction, and the thickness dimension of the first side wall is smaller than the thickness dimension of the second side wall.

[0013] According to the blade cell cover structure provided by the present invention, the height of the side wall of the lower side is 3-3.5 mm, and the wall thickness of the side wall is 0.7-1.3 mm.

[0014] According to the blade battery cell cover plate structure provided by the present invention, the mounting groove includes a bottom wall and circumferential side walls that are sequentially connected in the circumference and perpendicular to each other, and the thickness of the bottom wall is 0.65-1.0 mm.

[0015] A second aspect of the present invention provides a battery cell comprising the blade battery cell cover plate structure described in any one of the above items.

[0016] The blade cell cover plate structure and cell provided by the present invention have a flow opening on one side wall of the mounting groove, thereby enabling the flow opening to be connected with the surrounding gap, and enabling the electrolyte in the space around the pole bottom plate to be discharged in time, thereby avoiding long-term accumulation of electrolyte and affecting the overall safety performance of the cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 It is a three-dimensional structural schematic diagram of the blade battery cell cover structure provided by the present invention.

[0019] Figure 2 This is a front view of the blade battery cover structure provided by the present invention.

[0020] Figure 3 The present invention provides Figure 2 Cross-sectional view along the AA axis.

[0021] Figure 4 The present invention provides Figure 2 Cross-sectional view along the BB direction.

[0022] Reference numerals: 1. Shell; 2. Cover assembly; 21. First plastic part; 211. Mounting groove; 2111. Bottom wall; 2112. First side wall; 212. Flow port; 213. Reinforcement rib; 214. Support connection surface; 22. Metal base; 23. Second plastic part; 3. Pole bottom plate; 31. Pole body; 4. Insulating sealing sleeve; 41. First annular interference portion; 42. Second annular interference portion. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of explaining the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0025] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on specific circumstances.

[0026] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0027] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0028] The following combination Figures 1-4 The present invention describes a blade battery cover structure provided by the present invention, including a shell 1 and a cover assembly 2, the cover assembly 2 is connected to the shell 1, and part of the structure of the cover assembly 2 is located in the shell 1; the cover assembly 2 includes a metal base 22, a pole bottom plate 3, a first plastic part 21 and a second plastic part 23, the metal base 22 is connected to the shell 1, the first plastic part is arranged on one surface of the metal base 22, the second plastic part 23 is arranged on the other surface of the metal base 22, and the first plastic part 21 is located in the shell 1; a mounting groove 211 is formed in the first plastic part 21, the pole bottom plate 3 is arranged in the mounting groove 211, and there is a surrounding gap between the outer contour surface of the pole bottom plate 3 and the inner wall surface of the mounting groove 211; wherein, the mounting groove 211 is provided with at least one flow opening 212 on a side wall in the width direction Y of the first plastic part 21, the flow opening 212 is connected to the surrounding gap, and the flow opening 212 is used for natural discharge of electrolyte in the surrounding gap. Typically, electrolyte leaks from the gap between the pole bottom plate 3 and the plastic part. If the electrolyte accumulates around the pole bottom plate 3 for a long time, the electrolyte reacts with lithium ions to produce lithium dendrites. Over time, the lithium dendrites gradually grow outward along the gap between the pole bottom plate 3 and the first plastic rib, causing faults such as short circuits. In this embodiment, a flow port 212 is formed by providing a notch in a side wall of the mounting groove 211. After the battery cell is installed, the direction of electrolyte flow is defined within the mounting groove 211. This allows the electrolyte to flow out promptly through the flow port 212, preventing the electrolyte from accumulating in the mounting groove 211 for a long time. This avoids the problem of lithium dendrites growing into the gap between the pole bottom plate 3 and the plastic part due to long-term accumulation, thereby improving safety.

[0029] Specifically, the metal base 22 comprises a plain aluminum sheet, with a first plastic component 21 formed on its lower surface. This plastic component serves as a mounting platform for the pole base plate 3 and has a mounting groove 211 formed therein. The pole base plate 3 is entirely disposed within the mounting groove 211. A second plastic component 23 is formed on the upper surface of the plain aluminum sheet. Specifically, the first and second plastic components 21 and 23 collectively serve as an insulating layer, providing a certain degree of protection. In this embodiment, a flow port 212 is provided on the sidewall of the mounting groove 211 to facilitate the timely outflow of the electrolyte, preventing prolonged accumulation of electrolyte within the mounting groove 211 and the risk of a short circuit.

[0030] The plastic component is made of a hard plastic material, and the hard plastic material is used to provide sufficient strength, rigidity, and durability to ensure that the battery cover can withstand external pressure, vibration, impact, and other factors during actual use without deformation or damage. Specifically, engineering plastics or injection-molded hard plastics can be used. For example, polypropylene, polycarbonate, and other materials can be used.

[0031] Furthermore, if Figure 1 As shown, when the blade battery is installed, the cell cover is located on one side of the cell, which allows the electrolyte in the installation groove 211 to flow downward (the electrolyte flow direction in the figure). In this embodiment, a flow port 212 is provided on a side wall of the installation groove 211 that is perpendicular to the electrolyte flow direction. This allows the electrolyte in the surrounding gap to be discharged from the flow port 212, avoiding the accumulation of electrolyte in the installation groove 211 and achieving timely and rapid discharge of the electrolyte.

[0032] It is understandable that when lithium batteries, especially blade batteries, are installed as a whole, the poles of the battery cells are usually set downwards, and there is often electrolyte in the gap between the pole bottom plate 3 and the first plastic part 21, and the electrolyte flows downwards (such as Figure 1 Flow direction indicated in the figure). In the related art, in order to make the plastic first part have a higher structural strength, a grid-like reinforcing rib 213 structure is often provided in the area outside the mounting groove 211. This results in a "retaining wall" structure formed around the mounting area, causing the electrolyte to accumulate in the surrounding gap between the pole bottom plate 3 and the mounting groove 211. The electrolyte will react with lithium ions to produce lithium dendrites if it is accumulated for a long time, and will gradually grow outward along the gap between the pole bottom plate 3 and the plastic part. In this embodiment, a flow port 212 is provided on the side wall of the mounting groove 211, and the electrolyte in the mounting groove 211 can be discharged in a timely manner through the provided flow port 212, thereby avoiding the problem of lithium dendrites growing outward due to the long-term accumulation of the electrolyte.

[0033] When setting specific Figure 1As shown, the flow port 212 is constructed as a rectangular notch structure, and the flow port 212 can realize the communication between the internal space of the mounting groove 211 and the external space, so that the electrolyte will not accumulate in the mounting groove 211. It is understandable that the battery is usually not disassembled after installation. That is, an area for accumulating electrolyte is formed in the lower area of ​​the mounting groove 211 (the lower area when in use), and the electrolyte in the mounting groove 211 is discharged and flows into this area to achieve accumulation. Of course, in this embodiment, the number of notches is not limited, and it can be set to one, or it can be set to two or more. When two or more are set, the discharge speed of the electrolyte can be increased. When it is set to one, the overall structural strength can be strengthened and the difficulty of preparation can be reduced.

[0034] In combination with the above embodiment, the mounting groove 211 includes a bottom wall 2111 and a first side wall 2112, a second side wall, a third side wall and a fourth side wall. The bottom wall 2111 is used to form the lower surface of the mounting groove 211. The first side wall 2112, the second side wall, the third side wall and the fourth side wall are connected in sequence and are perpendicular to each other to form the circumferential side wall of the mounting groove 211. Among them, the first side wall 2112 is perpendicular to the flow direction of the electrolyte. The connection between the first side wall 2112 and the second side wall and the connection between the first side wall 2112 and the fourth side wall are both provided with a flow opening 212. The mounting groove 211 is used to connect to the pole bottom plate 3. When the electrolyte is discharged, it is discharged from the position of the flow opening 212. In this embodiment, the flow opening 212 is opened on both sides of the first side wall 2112 to achieve timely discharge of the electrolyte, and the limitation of the two flow openings 212 achieves efficient drainage.

[0035] Specifically, if Figure 1 As shown, when the battery cell is in use, the first sidewall 2112 serves as the bottom of the mounting groove 211 along the electrolyte flow direction, enabling rapid electrolyte discharge and preventing electrolyte accumulation within the mounting groove 211. Furthermore, the provision of two flow openings 212 not only enables rapid electrolyte outflow within the surrounding gap, but also ensures overall structural strength, preventing the overall structural strength from being affected by excessive gaps.

[0036] The first plastic part 21 is an elongated strip, and the mounting groove 211 is a rectangular groove structure, offset toward one end of the first plastic part 21. This creates ample storage space between the mounting groove 211 and the other end of the plastic part. The pole base plate 3 is positioned within the rectangular groove, with a surrounding gap between the outer wall of the pole base plate 3 and the inner wall of the mounting groove 211. When electrolyte accumulates within the surrounding gap, it can flow into the storage space through the flow port 212, thereby preventing the electrolyte from remaining in the mounting groove 211 for an extended period of time and potentially affecting the overall safety of the battery cell. Of course, it is understood that the amount of electrolyte that leaks out is generally small, and the storage space is fully capable of accommodating any leaked electrolyte.

[0037] In a specific embodiment, Figure 1 As shown, a grid-like rib structure is provided in the storage space below the installation groove 211 . The rib structure can enhance the overall structural strength, thereby making the first plastic component 21 have a higher structural strength.

[0038] In conjunction with the above embodiment, the plastic part includes a support and connection surface 214, the mounting groove 211 is provided on the support and connection surface 214, and the bottom wall 2111 of the mounting groove 211 is higher than the support and connection surface 214 of the first plastic part 21 in the thickness direction Z. The first plastic part 21 is an overall elongated structure, and has a sunken support and connection surface 214 between its two sides. The mounting groove 211 is located on the support and connection surface 214. In this embodiment, by providing the bottom wall 2111 of the mounting groove 211 on the support and connection surface 214 and ensuring that the bottom wall 2111 of the mounting groove 211 is higher than the support and connection surface 214, it is possible to facilitate the drainage of electrolyte in the mounting groove 211, thereby preventing residual electrolyte in the mounting groove.

[0039] Specifically, the bottom wall 2111 of the mounting groove 211 is higher than the supporting and connecting surface 214, which forms a stepped structure between the mounting groove 211 and the supporting and connecting surface 214. In other words, a height difference is formed between the two in the thickness direction Z, which facilitates the rapid outflow of the electrolyte in the mounting groove 211 and prevents electrolyte residue in the mounting groove 211.

[0040] It is understandable that the electrolyte may encounter flow resistance during the discharge process, resulting in incomplete discharge of the electrolyte in the surrounding gap. In this embodiment, by setting the support connection surface 214 lower than the lower surface of the mounting groove 211, the flow resistance during the electrolyte discharge process can be reduced, thereby facilitating the rapid and complete discharge of the electrolyte.

[0041] In some embodiments, a support structure is provided on the outer side of the sidewall of the mounting slot 211 where the flow opening 212 is formed. This support structure is used to strengthen the structural strength of the plastic component. The provision of the flow opening 212 weakens the overall structural strength of the first plastic component 21, which may affect the lifespan of the battery cell. In this embodiment, the provision of the support structure ensures that the first plastic component 21 has sufficient structural strength.

[0042] Specifically, the opening 212 on the sidewall of the mounting slot 211 may reduce the strength of the sidewall with the opening 212, thereby creating a weak point in the first plastic part 21 and shortening the lifespan of the battery cell. This embodiment strengthens the structural strength of the sidewall through the support structure, avoiding any weak points in the sidewall.

[0043] The support structure can take various forms, as long as it can enhance the structural strength of the sidewall. For example, the support structure can include a thickened layer on the outside of the sidewall to increase its structural strength, or reinforced ribs can be used to provide support.

[0044] In combination with the above embodiments, Figure 1 As shown, the support structure includes raised reinforcing ribs 213, and the reinforcing ribs 213 extend from the position of the circulation opening 212 along the length direction X of the first plastic part 21. The sidewalls of the mounting groove 211 have reduced structural strength at the circulation opening 212 due to the provision of the circulation opening 212. In this embodiment, by providing the reinforcing ribs 213 at the position of the circulation opening 212, the structural strength of the sidewalls can be improved.

[0045] Specifically, the reinforcing ribs 213 are configured as obliquely arranged structures, and the reinforcing ribs 213 can provide support for the side walls of the mounting groove 211, thereby strengthening the structural strength of the side walls and improving the overall structural strength of the first plastic part 21. Figure 1 As shown, the reinforcing rib 213 has an inclined slope structure, which can enhance the supporting effect of the reinforcing rib 213 and achieve stable support of the reinforcing rib 213.

[0046] In some embodiments, a pole body 31 with a columnar structure is provided on the pole base plate 3, and the pole body 31 is passed through the first plastic part 21 and the metal base 22, and is passed through the second plastic part 23; wherein, the outer sleeve of the pole body 31 is provided with an insulating sealing sleeve 4, and the metal base 22 and the second plastic part 23 are both interference fit with the insulating sealing sleeve 4. When the overall structure is assembled, it is assembled by crimping, which requires ensuring the structural strength of the installation. The electrolyte needs to be prevented from overflowing to the outside during the flow process, and the position of the pole body 31. In this embodiment, the provision of the insulating sealing sleeve 4 makes the overall structural strength higher and has a tighter structural layout. The interference fit can achieve a high-strength assembly connection on the one hand, and the sealing of the pole body 31 on the other hand to prevent electrolyte overflow.

[0047] Specifically, a pole body 31 is formed on the pole base plate 3. The pole body 31 extends from the first plastic part 21, the metal base 22, and the second plastic part 23. The end of the pole body 31 is located outside the blade cell cover structure, thereby enabling current conduction. The insulating sealing sleeve 4 is mounted on the pole body 31 and has an interference fit with the metal base 22 and the second plastic part 23, thereby ensuring a stable connection between the insulating sealing sleeve 4 and forming a well-sealed structure, thereby preventing overflow of electrolyte from the pole body 31.

[0048] It can be understood that the pole bottom plate 3 is a plate-like structure, and the main section of the pole body 31 passes through the bottom wall 2111 of the installation groove 211, the metal base 22, and part of the main body of the second plastic part 23. After the leaked electrolyte reaches the installation groove 211, on the one hand, the electrolyte is promptly discharged through the flow port 212 opened, and on the other hand, it is sealed by the insulating sealing sleeve 4 to prevent the electrolyte from overflowing from part of the pole body 31.

[0049] In combination with the above embodiments, Figure 3 As shown, the first plastic component 21, the metal base 22, and the second plastic component 23 are each provided with a concentrically arranged communication hole. The pole 31 is positioned within the communication hole, and a mounting gap C is formed between the pole 31 and the communication hole. The mounting gap C is 0.7-1.0 mm. The insulating sealing sleeve 4 is positioned within the mounting gap C, and the gap C is filled with an 80%-90% fill ratio. The provision of the communication hole facilitates overall crimping assembly. By limiting the size and fill ratio of the mounting gap C, short circuits caused by contact between the pole 31 and other metal components can be further avoided, thereby improving overall safety.

[0050] Specifically, through-hole structures are provided in the first plastic component 21, the metal base 22, and the second plastic component 23. These through-hole structures are arranged concentrically, thereby enabling the installation of the pole 31. The provision of the installation gap C facilitates the installation of the insulating sealing sleeve 4, providing space for quick installation and improving installation convenience. In specific applications, the filling ratios of the installation gap C are 80%, 83%, 86%, 90%, and 95%.

[0051] It is understood that the entire structure of the insulating sealing sleeve 4 is located within the installation gap C. By limiting the proportion between the insulating sealing sleeve 4 and the installation gap C and making the insulating sealing sleeve 4 occupy most of the installation gap C, this not only facilitates the installation of the insulating sealing sleeve 4 but also provides stronger structural support strength, making the overall structure more stable.

[0052] Specifically, the thickness of the insulating sealing sleeve 4 is 0.5-0.7 mm. By limiting the thickness of the insulating sealing sleeve 4, it has a higher structural strength, and the overall structural strength is also higher.

[0053] In a specific embodiment, the insulating sealing sleeve 4 includes a main body and an annular retaining portion. The annular retaining portion is provided at one end of the main body and has an outer diameter greater than that of the main body. A first annular interference portion 41 is formed between the annular retaining portion and the metal base 22, and a second annular interference portion 42 is formed between the main body and the second plastic component 23. The provision of the insulating sealing sleeve 4 improves the overall sealing performance of the installation and the stability of the overall assembly, achieving a highly stable connection assembly.

[0054] Specifically, the insulating sealing sleeve 4 is in a cylindrical structure as a whole and is sleeved on the outside of the pole body 31. By installing it in this way, interference fitting is achieved in the axial and radial directions, thereby improving the overall structural stability.

[0055] In combination with the above embodiments, Figure 3 As shown, the first annular interference portion 41 has an axial interference of 0.2-0.5mm in its axial direction (i.e., the thickness direction Z of the first plastic part), and an interference of 0.4-0.5mm in its radial direction (i.e., the width direction Y of the first plastic part). The second annular interference portion 42 has an axial interference of 0.4-0.5mm in its axial direction (i.e., the thickness direction Z of the first plastic part), and an interference of 0.8-1.1mm in its width direction (i.e., the width direction Y of the first plastic part). By limiting the interference, the fit strength and stability can be improved, the assembly process can be optimized, the difficulty can be reduced, and deformation and stress concentration can be reduced.

[0056] Specifically, by limiting the interference fit of the insulating sealing sleeve 4 in the thickness direction Z and the width direction Y, the two components have a stronger bonding force in this direction, which can effectively prevent relative movement, enhance the strength and stability of the fit, and provide a good annular sealing effect, avoiding electrolyte overflow.

[0057] Furthermore, by limiting the range of interference fit, the difficulty and accuracy of assembly can be more precisely controlled. Directions with smaller interference fits (e.g., 0.2-0.5 mm in the thickness direction Z) can make the assembly process easier and avoid assembly difficulties caused by excessive interference forces. Larger interference fits in the width direction Y (e.g., 0.8-1.1 mm) ensure a tight connection between the components while maintaining sufficient fit without affecting assembly. In an interference fit, excessive interference fit can cause excessive deformation or stress concentration in the components, thereby affecting the long-term reliability of the parts. By reasonably limiting the interference fits in different directions, it is possible to ensure that stress in each direction is within an acceptable range, avoiding unnecessary excessive compression or deformation. For example, in this embodiment, a larger interference fit in the width direction Y (0.8-1.1 mm) can provide sufficient fit without affecting other directions, while a smaller interference fit in the thickness direction Z (0.2-0.5 mm) reduces deformation caused by excessive compression.

[0058] In some embodiments, such as Figure 3As shown, the widthwise spacing W between the two sidewalls of the terminal base plate 3 in the width direction Y and the inner wall of the housing 1 on each side is 1.5-5 mm. The housing 1 is typically made of metal. If lithium dendrites formed by accumulated electrolyte come into contact with the housing 1, there is a risk of overlapping the terminal and the housing 1, causing a short circuit. In this embodiment, the spacing in the widthwise direction is limited to prevent overlapping lithium dendrites.

[0059] Specifically, too small a spacing can cause contact between the terminal base plate 3 and the battery housing 1, leading to a short circuit. In severe cases, this can cause internal short circuits, overheating, or even fire in the battery. By limiting the spacing to 1.5-3mm, the risk of contact between the terminal base plate 3 and the housing 1 can be effectively reduced, thereby reducing the possibility of short circuits and improving battery safety.

[0060] In some embodiments, such as Figure 1 As shown, the first plastic component 21 includes a first side wall and a second side wall disposed opposite each other in the width direction, with the first side wall having a smaller dimension in the thickness direction Z than the second side wall. Specifically, the first plastic component 21 has a first side wall and a second side wall disposed opposite each other, with the first side wall extending in the thickness direction Z less than the second side wall, thereby forming a height difference between the first side wall and the second side wall in the thickness direction. This height difference enables the component to cooperate with other structures on the cover plate, thereby improving the overall structural tightness.

[0061] Specifically, the pole bottom plate 3 is arranged on the main body in the width direction Y between the first side wall and the second side wall, and the first plastic parts 21 on both sides of the pole bottom plate 3 are provided with grid-shaped reinforcement ribs 213, which improve the overall strength of the first plastic part 21.

[0062] In combination with the above embodiments, Figure 3 As shown, the height H of the side wall of the lower side is 3-3.5 mm, and the thickness T1 of the side wall is 0.7-1.3 mm. By limiting the size of the side wall, it can better prevent electrolyte overflow and avoid problems such as short circuit.

[0063] Specifically, by limiting the height of the side wall, there is sufficient storage space at the bottom of the first plastic part 21 to achieve the storage of the electrolyte.

[0064] In some embodiments, such as Figure 4As shown, the mounting groove 211 includes a bottom wall 2111 and circumferentially connected, mutually perpendicular circumferential side walls. The thickness T2 of the bottom wall 2111 is 0.65-1.0 mm. The pole bottom plate 3 contacts the bottom wall 2111 of the mounting groove 211. The thickness of the bottom wall 2111 directly affects the distance between the pole bottom plate 3 and the metal base 22. This embodiment limits the thickness to a reasonable range to avoid short circuits.

[0065] A second aspect of the present invention provides a battery cell comprising the blade cell cover structure provided in any of the above embodiments. The battery cell comprises a housing 1, an electrode assembly, an electrolyte, a bare cell insulating sheet, and a cell cover, wherein the cell cover adopts the blade cell cover structure provided in any of the above embodiments.

[0066] Specifically, the battery cell provided in this example has the blade battery cell cover structure of any of the aforementioned embodiments, so the battery cell in this embodiment has the characteristic effects of each embodiment of the aforementioned blade battery cell cover structure. In order to avoid the redundancy of the effect description, it will not be repeated here.

[0067] The blade cell cover structure mentioned above is explained below through specific examples. Among them, eight groups of blade cell cover structures of different specifications were selected, which have the same structure except for the different specifications. Three groups of comparative examples were set up. The three groups of comparative examples have the same structure and adopt the above-mentioned cell cover structure, but the specifications and sizes are different. The cells were disassembled and packaged one year later to track whether there are lithium dendrites inside the abnormal short-circuited cells, which causes the internal pole of the cell to short-circuit with the cover / shell 1. The specific results are shown in the following table.

[0068] It can be seen from the above that when the internal structural dimensions of the blade battery cell cover meet: the gap between the pole bottom plate 3 and the shell 1: 1.5≤W≤3mm, the side wall height of the first plastic part 21 on the lower side of the retaining wall is 3.0≤H≤3.5mm, the wall thickness is 0.7≤T1≤1.3, and the wall thickness of the bottom wall 2111 below the pole bottom plate 3 is 0.65≤T2≤1.0mm, as the battery cell is recycled, a small amount of lithium dendrites appear, but does not cause internal overlap of the battery cell; when the first plastic part 21 is too low or the distance between the pole bottom plate 3 and the shell 1 is too small, lithium dendrites grow along the pole bottom plate 21 to the cover plate bare aluminum sheet or the shell 1, resulting in an increased risk of battery cell structure overlap.

[0069] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment, by providing a flow port 212 on a side wall of the mounting slot 211, enables the flow port 212 to communicate with the surrounding gap, thereby enabling the timely discharge of electrolyte from the space around the pole base plate 3, thereby preventing prolonged accumulation of electrolyte and thus affecting the overall safety performance of the battery cell. Furthermore, by limiting the internal structural dimensions of the blade battery cell cover, the safety of the battery cell structure is improved.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A blade battery cover structure, characterized in that: include: A shell and a cover assembly, wherein the cover assembly is connected to the shell, and a portion of the cover assembly is located inside the shell; The cover assembly includes a metal base, a pole bottom plate, a first plastic part, and a second plastic part. The metal base is connected to the housing. The first plastic part is provided on one surface of the metal base, and the second plastic part is provided on the other surface of the metal base. The first plastic part is located inside the housing. A mounting groove is formed in the first plastic part. The pole bottom plate is provided in the mounting groove. A surrounding gap is formed between the outer contour surface of the pole bottom plate and the inner wall surface of the mounting groove. Wherein, at least one flow opening is formed on a side wall of the installation groove in the width direction of the first plastic part, and the flow opening is communicated with the surrounding gap.

2. The blade battery cover structure according to claim 1, characterized in that: A columnar column body is provided on the pole bottom plate, and the pole body is passed through the first plastic part and the metal base, and is also passed through the second plastic part; Wherein, the outer sleeve of the pole body is provided with an insulating sealing sleeve, and the metal base and the second plastic part are both interference-fitted with the insulating sealing sleeve.

3. The blade cell cover structure according to claim 2, characterized in that: The insulating sealing sleeve includes a main body and an annular limiting portion, wherein the annular limiting portion is provided at one end of the main body, and the outer diameter of the annular limiting portion is greater than the outer diameter of the main body; A first annular interference portion is formed between the annular limiting portion and the metal base, and a second annular interference portion is formed between the main body and the second plastic component.

4. The blade cell cover plate structure according to claim 3, characterized in that: The axial interference of the first annular interference portion in its own axial direction is 0.2-0.5 mm, and the radial interference of the first annular interference portion in its own radial direction is 0.4-0.5 mm; The axial interference of the second annular interference portion in its own axial direction is 0.4-0.5 mm, and the radial interference of the second annular interference portion in its own radial direction is 0.8-1.1 mm.

5. The blade cell cover plate structure according to claim 2, characterized in that: The first plastic part, the metal base and the second plastic part are all concentrically provided with a communication hole, the pole body is arranged in the communication hole, and an installation gap is formed between the pole body and the communication hole; The installation gap is 0.7-1.0 mm, the insulating sealing sleeve is located in the installation gap, and the filling ratio between the insulating sealing sleeve and the installation gap is 80%-95%.

6. The blade cell cover plate structure according to claim 1, characterized in that: The distances between the two side walls of the pole bottom plate in the width direction and the inner wall surface of the shell on one side thereof in the width direction are both 1.5-5 mm.

7. The blade battery cover structure according to claim 1, characterized in that: The first plastic part includes a first side wall and a second side wall that are opposite to each other in the width direction. The thickness dimension of the first side wall is smaller than the thickness dimension of the second side wall.

8. The blade battery cover structure according to claim 7, characterized in that: The side wall of the lower one has a height of 3-3.5 mm and a thickness of 0.7-1.3 mm.

9. The blade battery cover structure according to claim 1, characterized in that: The mounting groove includes a bottom wall and circumferential side walls that are sequentially connected in the circumferential direction and are perpendicular to each other. The thickness of the bottom wall is 0.65-1.0 mm.

10. A battery cell, characterized in that: It comprises the blade battery cell cover plate structure according to any one of claims 1 to 9.

Images