Battery cell cover plate assembly and battery cell

Abstract

The application relates to the technical field of batteries and discloses a battery cell cover plate assembly and a battery cell. The battery cell cover plate assembly comprises a cover plate provided with a through hole along a Z direction; a lower plastic layer located on the lower surface of the cover plate and provided with a first through hole and a second through hole arranged at intervals, the first through hole being arranged opposite to the through hole; a connecting sheet located on one side of the lower surface of the lower plastic layer and comprising a pole post connecting part and a tab connecting part connected with each other, the pole post connecting part being provided with a pole post connecting hole; a pole post having an upper end and a lower end along the Z direction, the lower end of the pole post being inserted into the pole post connecting hole and being electrically connected with the pole post connecting part, the upper end of the pole post being sequentially penetrated through the first through hole and the through hole along the Z direction; and an insulating adhesive layer at least partially located in the second through hole, the opposite sides of the insulating adhesive layer being connected with the lower surface of the cover plate and the tab connecting part along the Z direction. The cover plate and the tab connecting part are connected through the insulating adhesive layer, so that the connecting sheet can be prevented from being deformed under the traction of the tab or the pole group.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a cell cover assembly and a cell. Background Technology

[0002] In the battery cell structure, the connecting piece serves as the electrical connection between the terminal and the tab, ensuring electrical conduction between them and guaranteeing stable current transmission within the cell. However, during actual use, if the cell is subjected to external forces, the connecting piece is prone to deformation due to the tension of the electrode assembly or tab. This can lead to gaps or even breakage at the welded joints between the connecting piece and the terminal or tab, adversely affecting the cell's safety and lifespan. Summary of the Invention

[0003] This invention provides a cell cover plate assembly and a cell to solve the problem that the connecting piece is prone to deformation under the pulling action of the electrode group or electrode tab.

[0004] In a first aspect, the present invention provides a battery cell cover assembly, comprising:

[0005] The cover plate has a clearance hole that extends through the Z direction;

[0006] The lower plastic, along the Z direction, is located on the lower surface of the cover plate. The lower plastic is provided with a first through hole and a second through hole spaced apart on the XY plane. The first through hole is opposite to the clearance hole, and the second through hole is provided with an insulating adhesive layer.

[0007] A connecting piece, along the Z direction, is located on one side of the lower surface of the lower plastic. The connecting piece includes a connected pole post connecting part and a pole tab connecting part. The pole post connecting part is provided with a pole post connecting hole, which is opposite to the clearance hole. The pole tab connecting part is opposite to the second through hole.

[0008] The electrode post, along the Z direction, has an upper end and a lower end. The lower end of the electrode post is inserted into the electrode post connection hole and electrically connected to the electrode post connection part. Along the Z direction, the upper end of the electrode post passes through the first through hole and the clearance hole in sequence.

[0009] An insulating adhesive layer, at least partially located within the second through hole, is connected along the Z direction to the lower surface of the cover plate and the electrode tab connection portion on opposite sides.

[0010] Beneficial effects: This invention provides an insulating adhesive layer in the second through hole of the lower plastic of the battery cell cover assembly. The insulating adhesive layer is connected to the lower surface of the cover plate and the electrode tab connection part of the connecting piece on opposite sides along the Z direction, forming a rigid limiting and fixing support for the electrode tab connection part of the connecting piece. This effectively counteracts the tensile force generated by the electrode group or electrode tab on the connecting piece when the battery cell is subjected to external force, avoids deformation of the connecting piece, and prevents gaps or breaks at the connection parts of the connecting piece and the electrode post and electrode tab. This ensures the stability of the current transmission inside the battery cell and improves the safety and service life of the battery cell. Furthermore, this invention inserts the lower end of the electrode post into the electrode post connection hole and electrically connects it to the electrode post connection part of the connecting piece, which can achieve stable and reliable electrical conduction between the electrode post and the connecting piece. At the same time, combined with the assembly structure in which the upper end of the electrode post passes through the first through hole and the clearance hole in sequence, it not only ensures the connection requirements between the electrode post and the external circuit, but also further enhances the structural stability of the connection part between the electrode post and the connecting piece through the limiting cooperation of the multi-layer structure, reducing the additional stress on the connecting piece caused by the shaking of the electrode post. It forms a synergistic effect with the supporting and limiting effect of the insulating adhesive layer, optimizing the structural reliability of the cell cover plate assembly from two dimensions and further extending the service life of the cell.

[0011] In one optional embodiment, the pole connection hole includes a first connection hole and a second connection hole that communicate along the Z direction. In the XY plane, the cross-sectional area of ​​the first connection hole is larger than that of the second connection hole. The connection between the first connection hole and the second connection hole forms a stepped surface. The second connection hole is located on the side of the pole connection hole closer to the cover plate. At least a portion of the lower end of the pole is inserted into the second connection hole, and the outer peripheral wall of the pole located in the second connection hole abuts against the inner wall of the second connection hole in the XY plane.

[0012] Beneficial effects: With the help of the fitting structure between the second connecting hole and the pole post, a reliable radial limiting constraint can be formed on the pole post, thereby effectively limiting the swaying and displacement of the pole post in the XY plane and avoiding the application of additional tensile stress to the connecting piece due to the swaying of the pole post.

[0013] In one optional embodiment, the lower end of the pole is located inside the second connecting hole, and the lower end face of the pole is flush with the stepped surface.

[0014] Beneficial effects: By confining the lower end of the electrode post within the second connecting hole and aligning the lower end face of the electrode post with the stepped surface at the connection between the first and second connecting holes, this invention ensures a flat and uniform contact surface between the electrode post and the connecting piece, preventing localized stress concentration caused by uneven end faces and reducing the risk of deformation or cracking of the connecting piece due to uneven stress. Furthermore, the flat end face structure provides a stable reference surface for subsequent welding operations between the electrode post and the connecting piece, facilitating uniform filling and spreading of solder into the welding area, improving the welding strength and electrical connection reliability of the electrode post and connecting piece. Combined with the radial confinement effect of the second connecting hole on the electrode post, this further optimizes the connection stability between the electrode post and the connecting piece, ensuring the continuity of current transmission within the battery cell, thereby enhancing the safety and lifespan of the battery cell.

[0015] In one optional embodiment, along the Z direction, the length of the second connecting hole is f, and the value of f is in the range of 0.5mm≤f≤1.5mm; and / or, on the XY plane, the width of the step surface is e, and the value of e is in the range of 0.5mm≤e≤2mm; and / or, the pole post is welded to the connecting piece, and along the Z direction, the weld depth at the weld between the pole post and the connecting piece is g, and the value of g is in the range of 0.3mm≤g≤1.5mm.

[0016] Beneficial Effects: This invention limits the length f of the second connecting hole to 0.5mm ≤ f ≤ 1.5mm, ensuring sufficient contact length between the electrode and the inner wall of the second connecting hole, guaranteeing radial limiting and the reliability of the connection strength, and preventing electrode wobbling; it also avoids material waste and structural redundancy caused by excessive hole length, while meeting the lightweight design requirements of the component. This invention limits the width e of the step surface to 0.5mm ≤ e ≤ 2mm, providing ample space for solder to ensure uniform solder spread, while avoiding excessive space occupation due to an overly wide step surface or insufficient space to meet welding process requirements due to an overly narrow step surface. This invention limits the solder depth g at the welding point between the electrode and the connecting piece to 0.3mm ≤ g ≤ 1.5mm, ensuring a strong welded connection between the electrode and the connecting piece, improving the stability and conductivity of the electrical connection; it also avoids damage to the electrode or connecting piece due to excessively deep solder, or insufficient weld strength due to excessively shallow solder.

[0017] In one optional embodiment, the lower surface of the cover plate is provided with a first groove facing the opening of the second through hole; and / or, the electrode connecting part is provided with a second groove facing the opening of the second through hole; the insulating adhesive layer is partially filled in the first groove and / or the second groove.

[0018] Beneficial effects: This invention provides a first groove facing the opening of the second through hole on the lower surface of the cover plate, and / or a second groove facing the opening of the second through hole on the electrode connection part, and the insulating adhesive layer filling the second through hole partially fills the first groove and / or the second groove, forming an interlocking structure between the insulating adhesive layer and the connecting piece and the cover plate. This effectively constrains the displacement and deformation of the connecting piece by means of the bonding and limiting effect of the insulating adhesive layer, reduces the pulling effect of the electrode group or electrode on the connecting piece when the battery cell is subjected to external force, thereby avoiding gaps or breaks at the connection parts of the connecting piece and the electrode post and electrode, improving the structural stability and safety of the battery cell, and extending the service life of the battery cell.

[0019] In one optional embodiment, the cross-sectional area of ​​the first groove on the XY plane gradually increases from the opening of the first groove to the bottom of the first groove.

[0020] And / or, from the opening of the second groove to the bottom of the second groove, the cross-sectional area of ​​the second groove on the XY plane gradually increases.

[0021] Beneficial effects: By setting the first groove and / or the second groove to have a gradually increasing cross-sectional area in the XY plane from the groove opening to the groove bottom, the insulating adhesive layer filled in the groove forms an "inverted platform" interlocking shape. Compared with grooves with equal cross-section or constricted opening, this invention can enhance the mechanical interlocking force and anti-disengagement ability between the insulating adhesive layer and the connecting piece and cover plate, further improve the constraint effect on the displacement and deformation of the connecting piece, effectively counteract the pulling effect of the electrode group or electrode tab on the connecting piece when the cell is subjected to external force, and avoid gaps or breaks at the connection parts of the connecting piece and the electrode post and electrode tab, thereby improving the structural reliability of the cell cover plate assembly and the safety and service life of the cell.

[0022] In one optional embodiment, the first groove is shaped like a frustum, and the angle between the groove wall of the first groove and the central axis of the first groove is A, where the value of A is in the range of 10°≤A≤45°.

[0023] And / or, the second groove is shaped like a frustum, and the angle between the groove wall of the second groove and the central axis of the second groove is B, with the value of B ranging from 10° to 45°.

[0024] Beneficial effects: The frustum-shaped first and / or second grooves, with an included angle design of 10° to 45°, ensure a smooth filling path during glue injection, avoiding problems such as obstructed glue flow and insufficient filling due to too small an included angle, or difficulties in stamping due to too large an included angle. At the same time, the groove walls within this angle range can form a stable mechanical interlocking structure with the cured insulating glue layer, enhancing the bonding strength between the insulating glue layer and the cover plate and connecting piece, further improving the supporting and limiting effect of the insulating glue layer on the connecting piece, effectively dispersing the stress generated by the pull of the electrode group or electrode tab, preventing deformation of the connecting piece, thereby ensuring the structural stability of the cell cover plate assembly and the service life of the cell.

[0025] In one optional embodiment, along the Z direction, the thickness of the connecting piece is a, and the value of a ranges from 1.2mm ≤ a ≤ 2mm; the groove depth of the second groove is b, and the value of b ranges from 0.3mm ≤ b ≤ 0.75 × a; and the relationship between a and b satisfies: 0.5mm ≤ ab;

[0026] And / or, along the Z direction, the thickness of the cover plate is c, where the value of c is 1.5mm≤c≤3mm; the groove depth of the first groove is d, where the value of d is 0.3mm≤d≤0.75×c.

[0027] Beneficial effects: A thickness design of 1.2mm≤a≤2mm ensures sufficient structural strength and current carrying capacity for the connecting piece while avoiding redundant design and space occupation within the cell. A groove depth limit of 0.3mm≤b≤0.75×a ensures ample space for the second groove to accommodate sufficient insulating adhesive, forming a stable anchoring structure and enhancing the bond strength between the insulating layer and the connecting piece. It also prevents excessive groove depth from penetrating the connecting piece or weakening its structural load-bearing capacity, thus preventing cracking. Furthermore, a thickness of 0.5mm≤ab utilizes the heat buffer layer created by the thickness difference, concentrating laser energy on the welding interface for reliable fusion while preventing damage to the substrate caused by excessive energy penetration. This ensures the structural strength and electrical connection stability of the electrode and connecting piece welding area, further improving cell safety and yield. The thickness design of 1.5mm≤c≤3mm ensures sufficient structural strength of the cover plate to withstand external impacts and prevent deformation and failure of the cover plate assembly, while effectively controlling the overall thickness and weight of the cover plate, meeting the design requirements of cell miniaturization and lightweighting. Furthermore, the cover plate within the above thickness range also has good heat dissipation capabilities, preventing heat accumulation at the connection between the connecting piece and the electrode tab. The groove depth limitation of 0.3mm≤d≤0.75×c ensures that the first groove has sufficient space to accommodate the adhesive, allowing for adequate filling of insulating adhesive to form a stable anchoring structure and enhancing the bonding strength between the insulating adhesive layer and the cover plate. It also prevents excessive groove depth from penetrating the cover plate or weakening its structural load-bearing capacity, thus preventing the risk of cover plate cracking.

[0028] In one optional embodiment, there are multiple first grooves, which are spaced apart on the XY plane; along the Z direction, the orthographic projection of the multiple first grooves toward the second through hole is located within the range of the second through hole; and / or, there are multiple second grooves, which are spaced apart on the XY plane; along the Z direction, the orthographic projection of the multiple second grooves toward the second through hole is located within the range of the second through hole.

[0029] Beneficial effects: By arranging multiple first grooves and / or multiple second grooves at intervals on the XY plane, and ensuring that the orthographic projections of both along the Z direction toward the second through hole fall within the range of the second through hole, this invention enables the insulating adhesive layer to form a multi-point dispersed anchoring structure during filling. This increases the mechanical interlocking area between the insulating adhesive layer and the cover plate and connecting piece, enhancing the bonding strength between the insulating adhesive layer and these components, and effectively preventing the insulating adhesive layer from peeling or falling off due to external pulling forces. On the other hand, the spaced grooves guide the uniform distribution of the insulating adhesive layer, avoiding local accumulation or gaps in the adhesive layer. This ensures that the supporting force of the insulating adhesive layer on the connecting piece tab is evenly transmitted. At the same time, the limited projection range allows the anchoring effect to be concentrated on the mating area between the insulating adhesive layer and the second through hole, avoiding structural redundancy and further enhancing the shear resistance of the insulating adhesive layer. This counteracts the tensile stress of the electrode group or tab on the connecting piece, preventing deformation of the connecting piece and ensuring the structural stability and safety of the battery cell.

[0030] Secondly, the present invention also provides a battery cell, comprising:

[0031] The housing has an opening at one end along the Z direction;

[0032] An electrode assembly is disposed within the housing, and an electrode tab is provided at one end of the electrode assembly near the opening;

[0033] In the aforementioned cell cover assembly, the cover is disposed over the opening, and the lower plastic is located inside the housing; the electrode connection portion is electrically connected to the electrode.

[0034] Beneficial effects: The battery cell of the present invention utilizes the rigid support and multi-point anchoring effect of the insulating adhesive layer on the connecting tab of the connecting piece, which can effectively offset the tensile stress generated on the connecting piece when the electrode group is subjected to external force, avoid the problem of deformation of the connecting piece, and ensure the stability of the current transmission inside the battery cell. At the same time, the matching assembly structure of the battery cell cover plate assembly with the shell and electrode group further improves the overall structural reliability and sealing of the battery cell, enhances the impact and vibration resistance of the battery cell, thereby extending the service life of the battery cell and improving the safety and yield of the battery cell. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of a battery cell cover assembly according to an embodiment of the present invention;

[0037] Figure 2 for Figure 1 A top view of the battery cell cover assembly shown;

[0038] Figure 3 for Figure 2 The cell cover assembly shown is a cross-sectional view along the MM perspective.

[0039] Figure 4 for Figure 3 A magnified view of a portion of P;

[0040] Figure 5 for Figure 3 A magnified view of a portion of Q;

[0041] Figure 6 for Figure 1 An exploded view of the battery cell cover assembly shown.

[0042] Figure 7 for Figure 1 Another exploded view of the battery cell cover assembly shown;

[0043] Figure 8 This is an exploded view of a battery cell according to an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Cover plate; 101. Clearance hole; 102. First groove; 103. Protrusion; 104. Receiving groove; 2. Lower plastic; 201. First through hole; 202. Second through hole; 3. Connecting piece; 301. Pole post connection part; 3011. Pole post connection hole; 30111. First connection hole; 30112. Second connection hole; 30113. Stepped surface; 302. Pole tab connection part; 3021. Second groove; 4. Pole post; 5. Insulating adhesive layer; 6. Housing; 7. Pole group; 701. Pole tab. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] The following is combined with Figures 1 to 8 The embodiments of the present invention are described below. For ease of description thereafter, as follows... Figure 1 As shown, a spatial rectangular coordinate system is established: the thickness direction of the cell cover assembly extends along the Z-axis; the length direction of the cell cover assembly extends along the X-axis; and the width direction of the cell cover assembly extends along the Y-axis.

[0048] According to embodiments of the present invention, in one aspect, such as Figure 1 , Figure 2 , Figure 3 , Figure 6 as well as Figure 7 As shown, a battery cell cover assembly is provided, including: a cover plate 1, a lower plastic 2, a connecting piece 3, and an electrode post 4.

[0049] Specifically, the cover plate 1 has a clearance hole 101 that extends through along the Z direction; along the Z direction, the lower plastic 2 is located on the lower surface of the cover plate 1, and the lower plastic 2 is provided with a first through hole 201 and a second through hole 202 spaced apart on the XY plane, the first through hole 201 being opposite to the clearance hole 101; along the Z direction, the connecting piece 3 is located on one side of the lower surface of the lower plastic 2, the connecting piece 3 includes a pole post connecting part 301 and a pole ear connecting part 302 connected together, the pole post connecting part 301 is provided with a pole post connecting hole 3011, and the pole post connecting hole 3011 is provided with a pole post connecting hole 3011. 11 is disposed opposite to the clearance hole 101, and the electrode connecting part 302 is disposed opposite to the second through hole 202; along the Z direction, the electrode post 4 has an upper end and a lower end, the lower end of the electrode post 4 is inserted into the electrode post connecting hole 3011 and electrically connected to the electrode post connecting part 301, and along the Z direction, the upper end of the electrode post 4 passes through the first through hole 201 and the clearance hole 101 in sequence; at least a portion of the insulating adhesive layer 5 is located in the second through hole 202, and along the Z direction, the opposite sides of the insulating adhesive layer 5 are respectively connected to the lower surface of the cover plate 1 and the electrode connecting part 302.

[0050] In this embodiment, an insulating adhesive layer 5 is provided in the second through hole 202 of the lower plastic 2 of the cell cover plate assembly. The insulating adhesive layer 5 is connected to the lower surface of the cover plate 1 and the tab connection portion 302 of the connecting piece 3 on opposite sides along the Z direction, forming a rigid limiting and fixed support for the tab connection portion 302 of the connecting piece 3. This effectively counteracts the pulling force generated by the pole group 7 or the tab 701 on the connecting piece 3 when the cell is subjected to external force, avoids deformation of the connecting piece 3, and prevents gaps or breaks at the connection points between the connecting piece 3 and the pole post 4 and the tab 701. This ensures the stability of the current transmission inside the cell and improves the safety and service life of the cell. Furthermore, in this embodiment, the lower end of the pole post 4 is inserted into the pole post connection hole 3011 and electrically connected to the pole post connection part 301 of the connecting piece 3. This enables stable and reliable electrical conduction between the pole post 4 and the connecting piece 3. At the same time, combined with the assembly structure in which the upper end of the pole post 4 passes through the first through hole 201 and the clearance hole 101 in sequence, it not only ensures the connection requirements between the pole post 4 and the external circuit, but also further enhances the structural stability of the connection part between the pole post 4 and the connecting piece 3 through the limiting cooperation of the multi-layer structure, reducing the additional stress on the connecting piece 3 caused by the shaking of the pole post 4. This forms a synergistic effect with the supporting and limiting effect of the insulating adhesive layer 5, optimizing the structural reliability of the cell cover assembly from two dimensions and further extending the service life of the cell.

[0051] It should be noted that the connection area between the connecting piece 3 and the tab 701 (i.e., the tab connection part 302) is the core node for current transmission inside the battery cell, and it generates a lot of heat during battery cell operation. Therefore, to prevent heat accumulation at this point, the insulating adhesive layer 5 can be set as an insulating and thermally conductive adhesive layer. In this way, the insulating and thermally conductive adhesive layer can not only provide stable support and limit for the connecting piece 3, offsetting the deformation stress generated by the tension of the electrode group 7 or the tab 701, but also conduct the heat generated in the connection area between the connecting piece 3 and the tab 701 to the cover plate 1 and dissipate it, achieving efficient heat dissipation. In addition, since the insulating adhesive layer 5 can prevent the connecting piece 3 from deforming under the tension of the electrode group 7 or the tab 701, the insulating adhesive layer 5 can always adhere to the connecting piece 3 and the cover plate 1, ensuring the continuity of heat conduction.

[0052] Specifically, the insulating adhesive layer 5 can be made of, but is not limited to, silicone, epoxy resin and polyurethane systems, with a thermal conductivity of 0.8 W / (m·K) to 6 W / (m·K).

[0053] Furthermore, such as Figure 5As shown, the pole connection hole 3011 includes a first connection hole 30111 and a second connection hole 30112 communicating along the Z direction. In the XY plane, the cross-sectional area of ​​the first connection hole 30111 is larger than that of the second connection hole 30112. The connection between the first connection hole 30111 and the second connection hole 30112 forms a stepped surface 30113. The second connection hole 30112 is located on the side of the pole connection hole 3011 closer to the cover plate 1. At least a portion of the lower end of the pole 4 passes through the second connection hole 30112, and the outer peripheral wall of the pole 4 in the XY plane abuts against the inner wall of the second connection hole 30112. It can be understood that, with the help of the fitting structure between the second connection hole 30112 and the pole 4, a reliable radial limiting constraint can be formed on the pole 4, thereby effectively limiting the swaying and displacement of the pole 4 in the XY plane and avoiding additional tensile stress on the connecting piece 3 due to the swaying of the pole 4.

[0054] Furthermore, such as Figure 5 As shown, the lower end of the pole post 4 is located inside the second connecting hole 30112, and the lower end surface of the pole post 4 is flush with the stepped surface 30113. It is understood that in this embodiment, by limiting the lower end of the pole post 4 within the second connecting hole 30112 and making the lower end face of the pole post 4 flush with the stepped surface 30113 at the connection between the first connecting hole 30111 and the second connecting hole 30112, the contact force surface between the pole post 4 and the connecting piece 3 can be kept flat and uniform, avoiding local stress concentration caused by misalignment of the end faces, and reducing the risk of deformation or cracking of the connecting piece 3 due to uneven stress. On the other hand, the flat end face structure can provide a stable reference surface for the subsequent welding operation of the pole post 4 and the connecting piece 3, which facilitates the uniform filling and spreading of solder to the welding area, improves the welding strength and electrical connection reliability of the pole post 4 and the connecting piece 3, and, combined with the radial limiting effect of the second connecting hole 30112 on the pole post 4, further optimizes the connection stability of the pole post 4 and the connecting piece 3, ensures the continuity of current transmission inside the battery cell, and thus enhances the safety and service life of the battery cell.

[0055] Furthermore, such as Figure 5 As shown, along the Z direction, the length of the second connecting hole 30112 is f, and the value of f ranges from 0.5mm ≤ f ≤ 1.5mm. It can be understood that in this embodiment, limiting the length f of the second connecting hole 30112 to 0.5mm ≤ f ≤ 1.5mm ensures sufficient contact length between the pole post 4 and the inner wall of the second connecting hole 30112, guaranteeing the reliability of radial limiting and the strength of the connection between the two, and preventing the pole post 4 from shaking; it also avoids material waste and structural redundancy caused by excessive hole length, while taking into account the lightweight design requirements of the component.

[0056] It is understandable that the value of f can be 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm or any value between the two.

[0057] Furthermore, such as Figure 5 As shown, on the XY plane, the width e of the step surface 30113 ranges from 0.5mm to 2mm. This embodiment limits the width e of the step surface 30113 to 0.5mm to 2mm, ensuring sufficient space for the solder to spread evenly. It also avoids the problems of excessive space occupation due to an overly wide step surface 30113, or insufficient space to meet welding process requirements due to an overly narrow step surface 30113.

[0058] It is understandable that the value of e can be 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm or any value between the two.

[0059] Furthermore, such as Figure 5 As shown, the electrode post 4 is welded to the connecting piece 3. Along the Z direction, the weld depth at the weld between the electrode post 4 and the connecting piece 3 is g, and the value of g ranges from 0.3mm to 1.5mm. In this embodiment, the weld depth g at the weld between the electrode post 4 and the connecting piece 3 is limited to 0.3mm to 1.5mm, which ensures that the electrode post 4 and the connecting piece 3 form a strong welded connection, improving the stability and conductivity of the electrical connection; at the same time, it avoids the defects of damage to the electrode post 4 or the connecting piece 3 due to excessively deep welds, or insufficient weld strength due to excessively shallow welds.

[0060] It is understandable that the value of g can be 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm or any value between the two.

[0061] In one embodiment, such as Figure 3 , Figure 4 , Figure 6 as well as Figure 8As shown, the lower surface of the cover plate 1 is provided with a first groove 102 that opens toward the second through hole 202; and / or, the electrode connecting part 302 is provided with a second groove 3021 that opens toward the second through hole 202; the insulating adhesive layer 5 is partially filled in the first groove 102 and / or the second groove 3021. In this embodiment, a first groove 102 opening toward the second through hole 202 is provided on the lower surface of the cover plate 1, and / or a second groove 3021 opening toward the second through hole 202 is provided on the tab connection portion 302. The insulating adhesive layer 5 filling the second through hole 202 is partially filled into the first groove 102 and / or the second groove 3021, forming an interlocking structure between the insulating adhesive layer 5, the connecting piece 3, and the cover plate 1. This effectively constrains the displacement and deformation of the connecting piece 3 by means of the bonding and limiting effect of the insulating adhesive layer 5, reducing the pulling effect of the electrode group 7 or the tab 701 on the connecting piece 3 when the battery cell is subjected to external force. This avoids gaps or breaks between the connecting piece 3 and the pole post 4 and the tab connection portion 302, improves the structural stability and safety of the battery cell, and extends the service life of the battery cell.

[0062] In one embodiment, such as Figure 3 and Figure 4 As shown, from the opening of the first groove 102 to the bottom of the first groove 102, the cross-sectional area of ​​the first groove 102 on the XY plane gradually increases; and / or, from the opening of the second groove 3021 to the bottom of the second groove 3021, the cross-sectional area of ​​the second groove 3021 on the XY plane gradually increases. It is understood that this embodiment sets the first groove 102 and / or the second groove 3021 to a structure in which the cross-sectional area gradually increases from the groove opening to the bottom in the XY plane, so that the insulating adhesive layer 5 filled in the groove forms an "inverted platform" fitting shape. Compared with grooves with equal cross-section or narrow opening, it can enhance the mechanical interlocking force and anti-disengagement ability between the insulating adhesive layer 5 and the connecting piece 3 and the cover plate 1, further improve the constraint effect on the displacement and deformation of the connecting piece 3, effectively counteract the pulling effect of the pole group 7 or the pole tab 701 on the connecting piece 3 when the cell is subjected to external force, and avoid gaps or breaks between the connecting piece 3 and the pole post 4 and the pole tab connection part 302, thereby improving the structural reliability of the cell cover plate assembly and the safety and service life of the cell.

[0063] Furthermore, such as Figure 4As shown, the first groove 102 is shaped like a frustum, and the angle between the groove wall of the first groove 102 and the central axis of the first groove 102 is A, with the value of A ranging from 10° to 45°; and / or, the second groove 3021 is shaped like a frustum, and the angle between the groove wall of the second groove 3021 and the central axis of the second groove 3021 is B, with the value of B ranging from 10° to 45°. It is understandable that the frustum-shaped first groove 102 and / or second groove 3021, with an included angle design of 10° to 45°, can ensure a smooth filling path during glue injection, avoiding problems such as obstructed glue flow and insufficient filling due to too small an included angle, or difficulties in stamping due to too large an included angle; at the same time, the groove wall in this angle range can form a stable mechanical interlocking structure with the cured insulating glue layer 5, enhancing the bonding strength between the insulating glue layer 5 and the cover plate 1 and connecting piece 3, further improving the supporting and limiting effect of the insulating glue layer 5 on the connecting piece 3, effectively dispersing the stress generated by the pulling of the electrode group 7 or the electrode tab 701, preventing deformation of the connecting piece 3, thereby ensuring the structural stability of the cell cover plate assembly and the service life of the cell.

[0064] It is understandable that the value of A can be 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, or any value between two of these. Similarly, it is understandable that the value of B can be 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, or any value between two of these.

[0065] Furthermore, such as Figure 4 As shown, along the Z direction, the thickness of the connecting piece 3 is 'a', with a value ranging from 1.2mm ≤ a ≤ 2mm; the groove depth of the second groove 3021 is 'b', with a value ranging from 0.3mm ≤ b ≤ 0.75 × a; and the relationship between a and b satisfies: 0.5mm ≤ ab. It can be understood that the thickness design of 1.2mm ≤ a ≤ 2mm ensures that the connecting piece 3 has sufficient structural strength and current carrying capacity, while avoiding redundant design and occupancy of the cell's internal space. The groove depth limitation of 0.3mm ≤ b ≤ 0.75 × a ensures that the second groove 3021 has sufficient space for adhesive, allowing for adequate filling of insulating adhesive to form a stable anchoring structure and enhancing the bonding strength between the insulating adhesive layer 5 and the connecting piece 3. It also prevents excessive groove depth from penetrating the connecting piece 3 or weakening its structural load-bearing capacity, thus preventing the risk of cracking in the connecting piece 3. With a thickness of 0.5mm≤ab, the heat buffer layer formed by the thickness difference can be utilized to concentrate the laser energy on the welding interface to achieve reliable fusion, while avoiding damage to the substrate caused by excessive energy penetration. This ensures the structural strength and electrical connection stability of the welding part between the tab 701 and the connecting piece 3, further improving the safety and yield of the battery cell.

[0066] It is understandable that the value of 'a' can be 1.2mm, 1.3mm, 1.5mm, 1.6mm, 1.8mm, 2mm, or any value between the two.

[0067] Furthermore, such as Figure 4 As shown, along the Z direction, the thickness of the cover plate 1 is c, where c ranges from 1.5mm to 3mm; the groove depth of the first groove 102 is d, where d ranges from 0.3mm to 0.75 × c. It can be understood that the thickness design of 1.5mm to 3mm ensures that the cover plate 1 has sufficient structural strength to withstand external impacts and avoids deformation and failure of the cover plate assembly, while effectively controlling the overall thickness and weight of the cover plate 1, meeting the design requirements of miniaturization and lightweighting of the battery cell. Furthermore, the cover plate 1 within the aforementioned thickness range also has good heat dissipation capabilities, preventing heat accumulation at the connection point between the connecting piece 3 and the tab 701. The groove depth limit of 0.3mm≤d≤0.75×c ensures that the first groove 102 has sufficient space to accommodate the adhesive, which can be filled with enough insulating adhesive to form a stable anchoring structure and enhance the bonding strength between the insulating adhesive layer 5 and the cover plate 1. It also prevents the cover plate 1 from being penetrated due to excessive groove depth or weakening the structural load-bearing capacity of the cover plate 1, thus preventing the cover plate 1 from cracking.

[0068] It is understandable that the value of c can be 1.5mm, 2mm, 2.5mm, 2.8mm, 3mm or any value between the two.

[0069] In one embodiment, such as Figure 3 , Figure 4 , Figure 6 as well as Figure 7As shown, there are multiple first grooves 102, which are spaced apart on the XY plane; along the Z direction, the orthographic projections of the multiple first grooves 102 toward the second through hole 202 are within the range of the second through hole 202; and / or, there are multiple second grooves 3021, which are spaced apart on the XY plane; along the Z direction, the orthographic projections of the multiple second grooves 3021 toward the second through hole 202 are within the range of the second through hole 202. It can be understood that by arranging multiple first grooves 102 and / or multiple second grooves 3021 spaced apart on the XY plane, and ensuring that the orthographic projections of both along the Z direction toward the second through hole 202 fall within the range of the second through hole 202, this embodiment, on the one hand, allows the insulating adhesive layer 5 to form a multi-point dispersed anchoring structure during filling, increasing the mechanical interlocking area between the insulating adhesive layer 5 and the cover plate 1 and connecting piece 3, improving the bonding strength between the insulating adhesive layer 5 and the two, and effectively preventing the insulating adhesive layer 5 from peeling or falling off due to external pulling force; on the other hand, ... The spaced grooves guide the insulating adhesive layer 5 to be evenly distributed, avoiding local accumulation or gaps in the adhesive layer. This ensures that the supporting force of the insulating adhesive layer 5 on the electrode tab connection 302 of the connecting piece 3 is evenly transmitted. At the same time, the limited projection range allows the anchoring effect to be concentrated on the mating area between the insulating adhesive layer 5 and the second through hole 202, avoiding structural redundancy and further enhancing the shear resistance of the insulating adhesive layer 5. This counteracts the tensile stress of the electrode group 7 or electrode tab 701 on the connecting piece 3, prevents deformation of the connecting piece 3, and ensures the structural stability and safety of the battery cell.

[0070] In one embodiment, such as Figures 1 to 4 , Figures 6 to 8As shown, the upper surface of the cover plate 1 protrudes in a direction away from the lower plastic 2 to form a protrusion 103. The protrusion 103 forms a receiving groove 104 on the lower surface side of the cover plate 1. A first groove 102 is provided on the bottom of the receiving groove 104. The insulating adhesive layer 5 is sandwiched between the bottom of the receiving groove 104 and the electrode tab connection part 302. In this embodiment, a raised bump 103 protruding away from the lower plastic 2 is provided on the upper surface of the cover plate 1, and a receiving groove 104 corresponding to the raised bump 103 is formed on the lower surface of the cover plate 1. At the same time, a first groove 102 is provided on the bottom of the receiving groove 104, so that the insulating adhesive layer 5 is sandwiched between the bottom of the receiving groove 104 and the electrode connection part 302. On the one hand, the structure of the raised bump 103 can improve the structural rigidity and deformation resistance of the cover plate 1, and enhance the performance of the cover plate 1 in resisting external impact. On the other hand, the structure of the raised bump 103 can provide a receiving space for the insulating adhesive layer 5 without affecting the overall compact layout of the battery cell, effectively avoiding the insulating adhesive layer 5 occupying extra space inside the battery cell, and ensuring that the energy density of the battery cell is not affected. Secondly, in conjunction with the first groove 102 at the bottom of the groove, the bonding effect between the insulating adhesive layer 5 and the cover plate 1 can be further optimized, and the bonding strength of the insulating adhesive layer 5 can be improved. In addition, the convex bulge 103 can increase the heat dissipation area of ​​the cover plate 1, accelerate the heat dissipation at the connection between the tab connection 302 and the tab 701, avoid the safety hazards caused by heat accumulation, and thus improve the structural reliability of the cell cover plate assembly and the safety and service life of the cell.

[0071] According to an embodiment of the present invention, on the other hand, such as Figure 8 As shown, a battery cell is also provided, including: a housing 6, an electrode group 7, and the aforementioned battery cell cover assembly.

[0072] Specifically, along the Z direction, one end of the housing 6 has an opening; the electrode group 7 is disposed inside the housing 6, and the end of the electrode group 7 near the opening is provided with an electrode tab 701; the cover plate 1 is placed over the opening, and the lower plastic 2 is located inside the housing 6; the electrode tab connecting part 302 is electrically connected to the electrode tab 701.

[0073] In this embodiment, the battery cell utilizes the rigid support and multi-point anchoring effect of the insulating adhesive layer 5 on the electrode tab connection portion 302 of the connecting piece 3. This effectively counteracts the tensile stress generated on the connecting piece 3 when the electrode group 7 is subjected to external forces, preventing deformation of the connecting piece 3 and ensuring the stability of current transmission within the battery cell. At the same time, the matching assembly structure of the battery cell cover assembly with the housing 6 and the electrode group 7 further enhances the overall structural reliability and sealing of the battery cell, strengthens its impact and vibration resistance, thereby extending its service life and improving its safety and yield.

[0074] It should be noted that, in order to avoid the insulating adhesive layer 5 interfering with the welding of the connecting piece and the tab, the lowest end of the insulating adhesive layer 5 should not be lower than the lower surface of the tab connection portion 302. Preferably, the tab 601 is located on the lower surface of the tab connection portion 302 and is welded to the lower surface of the tab connection portion 302.

[0075] The technical effects of the present invention will be described below with reference to some embodiments and comparative examples.

[0076] Table 1

[0077]

[0078] As can be seen from Table 1, by reasonably controlling the thickness a of the connecting piece 3, the groove depth b of the second groove 3021, the included angle A between the groove wall of the first groove 102 and the central axis of the first groove 102, and the difference (ab), the present invention can enable the insulating thermally conductive adhesive layer to stably connect the cover plate 1 and the connecting piece 3, offset the deformation stress generated by the pulling of the electrode group 7 or the electrode tab 701, and at the same time, the thermally conductive adhesive layer can also conduct the heat generated in the connection area between the connecting piece 3 and the electrode tab 701 to the cover plate 1 and dissipate it, thereby achieving efficient heat dissipation.

[0079] Specifically, in Examples 1 to 4: within the parameter range defined by the present invention, the cover plate 1 and the connecting piece 3 can achieve good adhesion through the insulating and thermally conductive adhesive layer, the bonding is stable and not easy to delaminate, thus ensuring good heat transfer effect; at the same time, the welding process of the tab 701 is normal, without defects such as pores or false welds, the yield is high and the reliability is good.

[0080] Comparative Example 1: The parameters are outside the preferred range of the present invention. Although (ab) is large, b is too small, which makes it easy for the connecting piece 3 and the cover plate 1 to delaminate, destroying the continuity of the insulating and thermally conductive adhesive layer, seriously affecting the heat transfer efficiency, and failing to meet the usage requirements.

[0081] Comparative Example 2: The included angle A is too small, resulting in poor adhesion between the connecting piece 3 and the cover plate 1. The insulating and thermally conductive adhesive layer is subjected to uneven force, which also leads to problems such as weak adhesion and easy peeling, resulting in poor thermal conductivity and reliability.

[0082] Comparative Example 3: (ab) is too small, the structural fit and stress distribution are unreasonable, resulting in poor hole formation during the welding of tab 701, poor welding quality, and inability to achieve a stable and reliable welding connection.

[0083] In summary, by synergistically optimizing and rationally controlling parameters a, b, angle A, and (ab), a tight fit and reliable adhesion between the cover plate 1 and the connecting piece 3 can be achieved, effectively preventing delamination and ensuring good thermal conductivity of the insulating and thermally conductive adhesive layer. Simultaneously, the welding process of the tab 701 is ensured to be stable and reliable, without defects such as pinholes. Through the rational matching of the above parameters, this invention significantly improves the assembly quality and reliability of the battery cell cover plate assembly.

[0084] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cell cover assembly, characterized in that, include: The cover plate has a clearance hole that extends through the Z direction; The lower plastic is located on the lower surface of the cover plate along the Z direction. The lower plastic is provided with a first through hole and a second through hole spaced apart on the XY plane. The first through hole is arranged opposite to the clearance hole. A connecting piece, along the Z direction, is located on one side of the lower surface of the lower plastic. The connecting piece includes a connected pole post connecting part and a pole tab connecting part. The pole post connecting part is provided with a pole post connecting hole, which is opposite to the clearance hole. The pole tab connecting part is opposite to the second through hole. The electrode post, along the Z direction, has an upper end and a lower end. The lower end of the electrode post is inserted into the electrode post connection hole and electrically connected to the electrode post connection part. Along the Z direction, the upper end of the electrode post passes through the first through hole and the clearance hole in sequence. An insulating adhesive layer, at least partially located within the second through hole, is connected along the Z direction to the lower surface of the cover plate and the electrode tab connection portion on opposite sides, respectively. The lower surface of the cover plate is provided with a first groove facing the opening of the second through hole; and / or, the electrode connecting part is provided with a second groove facing the opening of the second through hole; the insulating adhesive layer is partially filled in the first groove and / or the second groove; From the opening of the first groove to the bottom of the first groove, the cross-sectional area of ​​the first groove on the XY plane gradually increases; And / or, from the opening of the second groove to the bottom of the second groove, the cross-sectional area of ​​the second groove on the XY plane gradually increases.

2. The cell cover assembly according to claim 1, characterized in that, The pole connection hole includes a first connection hole and a second connection hole that are connected along the Z direction. In the XY plane, the cross-sectional area of ​​the first connection hole is larger than that of the second connection hole. The connection between the first connection hole and the second connection hole forms a stepped surface. The second connection hole is located on the side of the pole connection hole closer to the cover plate. At least a portion of the lower end of the pole is inserted into the second connection hole, and the outer peripheral wall of the pole located in the second connection hole abuts against the inner wall of the second connection hole in the XY plane.

3. The cell cover assembly according to claim 2, characterized in that, The lower end of the pole is located inside the second connecting hole, and the lower end face of the pole is flush with the stepped surface.

4. The cell cover assembly according to claim 3, characterized in that, Along the Z direction, the length of the second connecting hole is f, and the value of f is in the range of 0.5mm≤f≤1.5mm; and / or, on the XY plane, the width of the step surface is e, and the value of e is in the range of 0.5mm≤e≤2mm; and / or, the pole post is welded to the connecting piece, and along the Z direction, the weld depth at the weld between the pole post and the connecting piece is g, and the value of g is in the range of 0.3mm≤g≤1.5mm.

5. The cell cover assembly according to claim 1, characterized in that, The first groove is shaped like a frustum, and the angle between the groove wall and the central axis of the first groove is A, with the value of A ranging from 10° to 45°. And / or, the second groove is shaped like a frustum, and the angle between the groove wall of the second groove and the central axis of the second groove is B, with the value of B ranging from 10° to 45°.

6. The cell cover assembly according to claim 1, characterized in that, Along the Z direction, the thickness of the connecting piece is a, and the value of a is in the range of 1.2mm≤a≤2mm; the groove depth of the second groove is b, and the value of b is in the range of 0.3mm≤b≤0.75×a; and the relationship between a and b satisfies: 0.5mm≤ab; And / or, along the Z direction, the thickness of the cover plate is c, where the value of c is 1.5mm≤c≤3mm; the groove depth of the first groove is d, where the value of d is 0.3mm≤d≤0.75×c.

7. The cell cover assembly according to claim 1, characterized in that, The number of first grooves is multiple, and the multiple first grooves are spaced apart on the XY plane; along the Z direction, the orthographic projection of the multiple first grooves toward the second through hole is located within the range of the second through hole; and / or, the number of second grooves is multiple, and the multiple second grooves are spaced apart on the XY plane; along the Z direction, the orthographic projection of the multiple second grooves toward the second through hole is located within the range of the second through hole.

8. A battery cell, characterized in that, include: The housing has an opening at one end along the Z direction; An electrode assembly is disposed within the housing, and an electrode tab is provided at one end of the electrode assembly near the opening; The cell cover assembly according to any one of claims 1 to 7, wherein the cover is disposed over the opening, the lower plastic is located inside the housing, and the electrode connection portion is electrically connected to the electrode.

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