Battery cell cover plate assembly and battery cell

Abstract

The application relates to the battery technical field and discloses a battery cell cover plate assembly and a battery cell. The battery cell cover plate assembly comprises a cover plate, a lower plastic, a connecting sheet and a buckle. The lower plastic is located on the lower surface of the cover plate in the Z direction, the lower surface of the lower plastic is provided with the buckle in the Z direction, the connecting sheet is located on one side of the lower surface of the lower plastic in the Z direction and is provided with a through hole extending in the Z direction, and the lower end of the buckle penetrates through the through hole and is clamped with the lower surface of the connecting sheet in the Z direction. The buckle is arranged on the lower surface of the lower plastic, penetrates through the through hole of the connecting sheet and is clamped with the lower surface of the connecting sheet, so that the connecting sheet is firmly positioned on the lower plastic, and the displacement and deformation of the connecting sheet when the battery cell is subjected to external force are effectively limited.

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] Cover plate;

[0006] The lower plastic part, along the Z direction, is located on the lower surface of the cover plate, and a buckle is provided on the lower surface of the lower plastic part;

[0007] The connecting piece, along the Z direction, is located on one side of the lower surface of the lower plastic and has a through hole extending along the Z direction. Along the Z direction, the lower end of the buckle passes through the through hole and engages with the lower surface of the connecting piece.

[0008] Beneficial effects: This invention, through the design of setting a buckle on the lower surface of the lower plastic and using the buckle to pass through the through hole of the connecting piece and engage with the lower surface of the connecting piece, can firmly limit the connecting piece to the lower plastic, effectively restricting the displacement and deformation of the connecting piece when the battery cell is subjected to external force. This avoids gaps or even breakage at the connection between the connecting piece and the terminal or terminal due to the pulling of the electrode group or the electrode tab, thereby ensuring the stability of the current transmission inside the battery cell and improving the safety and service life of the battery cell.

[0009] In one optional embodiment, the buckle includes a connecting portion and a snap-fit ​​portion. Along the Z direction, one end of the connecting portion is connected to the lower surface of the lower plastic, and at least a portion of the connecting portion passes through the through hole. The snap-fit ​​portion is located at the other end of the connecting portion in the Z direction and is located outside the through hole. The snap-fit ​​portion snaps into the lower surface of the connecting piece.

[0010] Beneficial effects: This invention separates the buckle into a connecting part and a snap-fit ​​part. The connecting part passes through the through hole of the connecting piece to achieve positioning of the buckle and the connecting piece. Then, the snap-fit ​​part located outside the through hole engages with the lower surface of the connecting piece to form a bidirectional limiting constraint on the upper and lower sides of the connecting piece. This can further improve the connection stability between the connecting piece and the lower plastic, more effectively limit the displacement and deformation space of the connecting piece when it is pulled by external force, and prevent gaps or breaks at the connection points between the connecting piece and the pole or the tab. This ensures the stability of the current transmission of the battery cell and further enhances the safety and service life of the battery cell.

[0011] In one alternative embodiment, on the XY plane, the width of the connecting portion is smaller than the width of the snap-fit ​​portion, and the connection between the snap-fit ​​portion and the connecting portion forms a snap-fit ​​surface that snaps into the lower surface of the connecting piece.

[0012] Beneficial effects: By designing the width of the connecting part in the XY plane to be smaller than the width of the snap-fit ​​part, the connection between the two forms a snap-fit ​​surface that snaps against the lower surface of the connecting piece. This snap-fit ​​surface, in close contact with the connecting piece, reliably limits the connection of the connecting piece, preventing it from shifting along the Z direction under stress. Simultaneously, the radial limiting effect of the through-hole in the connecting part further enhances the tightness of the connection between the connecting piece and the lower plastic, reducing the risk of deformation caused by external force pulling on the connecting piece. This prevents gaps or breaks at the connection points between the connecting piece and the electrode post / ear, thereby ensuring the stability of the battery cell's current transmission, further extending the battery cell's lifespan, and improving the battery cell's safety.

[0013] In one optional embodiment, the snap-fit ​​portion includes a pair of sub-snap-fit ​​portions that are arranged opposite to each other and spaced apart on the XY plane. Along the Z direction, the orthographic projection of the sub-snap-fit ​​portions toward the connecting portion partially falls within the range of the connecting portion. The connection between the sub-snap-fit ​​portions and the connecting portion forms the snap-fit ​​surface. The end of the pair of sub-snap-fit ​​portions away from the connecting portion is provided with a chamfer.

[0014] Beneficial effects: By setting the snap-fit ​​portion as a pair of sub-snap-fit ​​portions arranged back-to-back on the XY plane, and ensuring that the orthographic projection of the sub-snap-fit ​​portions toward the connecting portion falls within the range of the connecting portion, the snap-fit ​​surfaces of the two sub-snap-fit ​​portions can form a symmetrical limiting of the connecting piece, improving the uniformity of force on the snap-fit ​​structure and preventing local deformation of the connecting piece due to unilateral force. At the same time, the chamfer provided at the end of the sub-snap-fit ​​portion away from the connecting portion can play a guiding role during the assembly process of the snap fastener passing through the through hole of the connecting piece, reducing assembly resistance, improving assembly efficiency, and also preventing sharp edges from scratching and damaging the connecting piece.

[0015] In one optional embodiment, on the XY plane, a gap 'a' is left between the outer wall of the connecting part and the wall of the through hole, and the value of 'a' ranges from 1mm to 3mm.

[0016] Beneficial Effects: This invention, by limiting the interval 'a' between the outer wall of the connecting part and the wall of the through hole to a reasonable range of 1mm ≤ a ≤ 3mm, ensures smooth snap-fit ​​assembly, avoids excessive occupation of the internal space of the battery cell, and guarantees the strength of the snap-fit ​​structure. It effectively suppresses deformation of the connecting piece under external force, preventing gaps or breaks in the connection, thereby ensuring stable current transmission in the battery cell and improving its safety and service life. It is understood that if the interval 'a' is less than 1mm, the gap between the connecting part and the through hole is too small, increasing the assembly resistance of the snap-fit ​​through the through hole, reducing assembly efficiency, and potentially causing damage to the edge of the through hole or the snap-fit ​​itself. If the interval 'a' is greater than 3mm, it not only occupies additional internal space of the battery cell but also requires increasing the thickness of the snap-fit ​​part to ensure the snap-fit ​​limiting effect, thus occupying the height space of the battery cell in the Z direction. Without increasing the thickness of the snap-fit ​​part, the snap-fit ​​structure will lack sufficient strength, making it difficult to effectively constrain the displacement and deformation of the connecting piece.

[0017] In one optional embodiment, on the XY plane, the width of the portion of the snap-fit ​​part that snaps into the lower surface of the connecting piece is b, and the value of b is in the range of 0.5mm≤b≤3mm.

[0018] Beneficial Effects: This invention limits the width b of the portion where the snap-fit ​​part engages with the lower surface of the connecting piece to a reasonable range of 0.5mm ≤ b ≤ 3mm. This ensures the stability of the snap-fit ​​structure, effectively suppresses the risk of deformation of the connecting piece, and also takes into account ease of assembly and a compact layout of the internal space of the battery cell. It is understood that if the width b is less than 0.5mm, the contact area between the snap-fit ​​part and the connecting piece is too small, resulting in insufficient fixing strength of the snap-fit ​​structure. This makes it difficult to effectively restrain the displacement and deformation of the connecting piece under external force, easily leading to gaps or breakage at the connection points between the connecting piece and the terminal post or tab. If the width b is greater than 3mm, it will not only occupy additional internal space of the battery cell, but also make it difficult for the snap-fit ​​part to pass smoothly through the through-hole of the connecting piece due to its excessive size, reducing assembly efficiency and potentially causing damage to the edge of the through-hole or the snap fastener.

[0019] In one optional embodiment, the upper surface of the cover plate protrudes in a direction away from the lower plastic to form a bulge, and the bulge forms a receiving groove on the lower surface side of the cover plate; the lower plastic is provided with a clearance hole; the battery cell cover plate assembly further includes a thermal pad, at least a portion of which passes through the clearance hole and is sandwiched between the bottom of the receiving groove and the upper surface of the connecting piece.

[0020] Beneficial Effects: This invention, by setting a protrusion on the cover plate, can form a receiving groove on the lower surface of the cover plate that matches the protrusion without affecting the overall compact layout of the battery cell. Combined with the clearance holes in the lower plastic, this provides a precise and stable installation space for the thermal pad, allowing it to be firmly clamped between the bottom of the receiving groove and the upper surface of the connecting piece. Secondly, the thermal pad can quickly conduct the heat generated by the current transmission of the connecting piece to the protrusion. The protrusion increases the contact area between the cover plate and the external environment, accelerating heat dissipation and preventing heat accumulation at the connection between the connecting piece and the tab, meeting the requirements of high charge / discharge rates. Furthermore, since the connecting piece in this embodiment does not easily deform, the thermal pad can always maintain a good fit with the connecting piece and the bottom of the receiving groove, thus ensuring the continuous unobstructed heat conduction path.

[0021] In one optional embodiment, on the XY plane, a gap c is left between the outer wall of the thermal pad and the wall of the clearance hole, where the value of c ranges from 0.5mm to 3mm.

[0022] Beneficial effects: This invention limits the gap c between the outer wall of the thermal pad and the wall of the clearance hole to within the range of 0.5mm≤c≤3mm. This provides sufficient tolerance space for the cell assembly process, effectively compensating for processing and assembly errors between the cover plate, the lower plastic, and the thermal pad, and preventing contact and compression between the thermal pad and the clearance hole wall due to dimensional deviations. Simultaneously, it prevents the thermal pad from shifting due to excessive gap, thus avoiding loss of stable support for the connecting piece. This ensures the thermal pad always adheres to the bottom of the receiving groove and the upper surface of the connecting piece, guaranteeing unobstructed heat conduction and maintaining good heat dissipation. Furthermore, this gap also provides buffer space for thermal expansion and contraction, preventing interference from deformation of components due to temperature changes during cell operation, further improving the structural stability and durability of the cell cover plate assembly.

[0023] In one optional embodiment, the thickness of the thermal pad along the Z direction is d, and the value of d is in the range of 1mm≤d≤3mm; the thickness of the thermal pad is greater than the thickness of the portion of the lower plastic sandwiched between the cover plate and the connecting piece.

[0024] Beneficial effects: On the one hand, the thickness design of 1mm≤d≤3mm ensures that the thermal pad has sufficient thermal conduction cross-sectional area, which can efficiently transfer heat at the connecting piece and avoid local heat accumulation. On the other hand, the thickness of the thermal pad is greater than the corresponding thickness of the lower plastic part, which allows the thermal pad to form a pre-tightening force after assembly, tightly clamping it between the bottom of the receiving groove and the upper surface of the connecting piece, eliminating the gap of the thermal interface and ensuring the smoothness of the heat conduction path.

[0025] Secondly, the present invention also provides a battery cell, comprising:

[0026] The housing has an opening at one end along the Z direction;

[0027] An electrode assembly is disposed within the housing, and an electrode tab is provided at one end of the electrode assembly near the opening;

[0028] In the aforementioned cell cover assembly, the cover is disposed over the opening, and the lower plastic is located inside the housing;

[0029] The pole has one end located inside the housing and the other end passing through the cover plate and located outside the housing;

[0030] One end of the connecting piece is electrically connected to the portion of the pole located inside the housing, and the other end is electrically connected to the tab.

[0031] Beneficial effects: The battery cell of this invention utilizes a snap-fit ​​and through-hole engagement structure to securely limit the position of the connecting piece, effectively restricting the displacement and deformation of the connecting piece when the battery cell is subjected to external forces. This prevents gaps or even breakage at the connection points between the connecting piece and the pole or tab due to the pulling of the pole group or tab. At the same time, it ensures the stability of current transmission within the battery cell, structurally solving the safety hazards caused by the deformation of the connecting piece in traditional battery cells. This improves the safety and service life of the battery cell. Furthermore, the compact design of this structure does not occupy excessive internal space of the battery cell, balancing the energy density and reliability of the battery cell. Attached Figure Description

[0032] 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.

[0033] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention;

[0034] Figure 2 This is a partial structural diagram of a battery cell according to an embodiment of the present invention;

[0035] Figure 3 This is an exploded view of a battery cell according to an embodiment of the present invention;

[0036] Figure 4 This is another exploded view of a battery cell according to an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Cover plate; 101. Protrusion; 102. Receiving groove; 2. Lower plastic; 201. Buckle; 2011. Connecting part; 2012. Snap-fit ​​part; 20121. Sub-snap-fit ​​part; 202. Clearance hole; 3. Connecting piece; 301. Through hole; 4. Thermal pad; 5. Housing; 6. Electrode assembly; 601. Electrode tab; 7. Electrode post. Detailed Implementation

[0039] 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.

[0040] The following is combined Figures 1 to 4 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.

[0041] According to embodiments of the present invention, such as Figure 2 and Figure 4 As shown, on one hand, a battery cell cover assembly is provided, including: a cover plate 1, a lower plastic 2, and a connecting piece 3.

[0042] Specifically, along the Z direction, the lower plastic 2 is located on the lower surface of the cover plate 1, and a buckle 201 is provided on the lower surface of the lower plastic 2; along the Z direction, the connecting piece 3 is located on one side of the lower surface of the lower plastic 2, and is provided with a through hole 301 extending along the Z direction; along the Z direction, the lower end of the buckle 201 passes through the through hole 301 and engages with the lower surface of the connecting piece 3.

[0043] This embodiment, by setting a buckle 201 on the lower surface of the lower plastic 2, and by using the buckle 201 to pass through the through hole 301 of the connecting piece 3 and engage with the lower surface of the connecting piece 3, can firmly limit the connecting piece 3 to the lower plastic 2, effectively restricting the displacement and deformation of the connecting piece 3 when the battery cell is subjected to external force, and preventing the pulling of the electrode group 6 or the electrode tab 601 from causing gaps or even breakage at the connection part 2011 between the connecting piece 3 and the electrode post 7 or the electrode tab 601, thereby ensuring the stability of the current transmission inside the battery cell and improving the safety and service life of the battery cell.

[0044] It should be noted that the reason why the connecting piece 3 is fixed to the lower plastic 2 by the buckle 201 and the through hole 301 can prevent the connecting piece 3 from deforming under the traction of the electrode group 6 or the electrode tab 601 is because the lower plastic 2 and the cover plate 1 can be fixed together by the positive electrode post and the negative electrode post. For example, the positive electrode post 7 and the negative electrode post 7 include an electrode post body and an electrode post base. The electrode post body passes through the lower plastic 2 and the cover plate 1 in sequence along the Z direction. The electrode post base is located on the lower surface of the lower plastic 2 and forms an abutment limit with the lower plastic 2. Subsequently, to make the positive electrode post 7, negative electrode post 7, lower plastic 2, and cover plate 1 form a whole, the electrode post body will be riveted. This will cause the end of the electrode post body that passes through the cover plate 1 to undergo plastic deformation and extend outward, forming a riveted part that abuts against the upper surface of the cover plate 1. At this point, the electrode post base and the riveted part will be clamped and fixed from the lower surface of the lower plastic 2 and the upper surface of the cover plate 1, respectively, locking the lower plastic 2 and the cover plate 1 into a rigid whole structure with no relative displacement. The connecting piece 3 will be firmly fixed on this rigid whole through the snap-fit ​​201 and the through hole 301. When the electrode group 6 or the electrode ear 601 is pulled by external force, the rigid support force of the cover plate 1 can be directly transmitted to the connecting piece 3 through the lower plastic 2 and the snap-fit ​​201, effectively offsetting the pulling force and fundamentally preventing the connecting piece 3 from being displaced or deformed.

[0045] In one implementation, the buckle 201 and the lower plastic 2 are integrally injection molded. Furthermore, to improve the limiting effect on the connecting piece 3, multiple buckles 201 can be provided on the lower plastic 2, and multiple through holes 301 corresponding to the multiple buckles 201 can be provided on the connecting piece 3.

[0046] In one embodiment, such as Figure 2 As shown, the buckle 201 includes a connecting part 2011 and a snap-fit ​​part 2012. Along the Z direction, one end of the connecting part 2011 is connected to the lower surface of the lower plastic 2, and at least part of the connecting part 2011 passes through the through hole 301. The snap-fit ​​part 2012 is located at the other end of the connecting part 2011 in the Z direction and is located outside the through hole 301. The snap-fit ​​part 2012 snaps into the lower surface of the connecting piece 3. It is understood that in this embodiment, the buckle 201 is divided into a connecting part 2011 and a snap-fit ​​part 2012. The connecting part 2011 is inserted into the through hole 301 of the connecting piece 3 to achieve the positioning of the buckle 201 and the connecting piece 3. Then, the snap-fit ​​part 2012 located outside the through hole 301 engages with the lower surface of the connecting piece 3 to form a bidirectional limiting constraint on the upper and lower sides of the connecting piece 3. This can further improve the connection stability between the connecting piece 3 and the lower plastic 2, and more effectively limit the displacement and deformation space of the connecting piece 3 when it is pulled by external force. It can also prevent gaps or breaks from appearing at the connection part 2011 between the connecting piece 3 and the pole post 7 and the pole tab 601, thereby continuously ensuring the stability of the current transmission of the battery cell and further enhancing the safety and service life of the battery cell.

[0047] Furthermore, such as Figure 2 As shown, on the XY plane, the width of the connecting part 2011 is smaller than the width of the snap-fit ​​part 2012, and the connection between the snap-fit ​​part 2012 and the connecting part 2011 forms a snap-fit ​​surface that snaps into the lower surface of the connecting piece 3. It is understood that in this embodiment, by designing the width of the connecting part 2011 in the XY plane to be smaller than the width of the snap-fit ​​part 2012, the connection between the two forms a snap-fit ​​surface that snaps against the lower surface of the connecting piece 3. This snap-fit ​​surface, by fitting and abutting against the connecting piece 3, reliably limits the connection of the connecting piece 3, preventing the connecting piece 3 from shifting along the Z direction when under force. At the same time, in conjunction with the radial limiting effect of the through hole 301 in the connecting part 2011, the connection between the connecting piece 3 and the lower plastic 2 is further strengthened, reducing the risk of deformation of the connecting piece 3 caused by external force pulling, and preventing gaps or breaks from appearing at the connection part 2011 between the connecting piece 3 and the pole post 7 and the pole tab 601. This ensures the stability of the current transmission of the battery cell, further extends the service life of the battery cell, and improves the safety of the battery cell.

[0048] Furthermore, such as Figure 2 As shown, the snap-fit ​​portion 2012 includes a pair of sub-snap-fit ​​portions 20121 that are arranged opposite to each other and spaced apart on the XY plane. Along the Z direction, a portion of the orthographic projection of the sub-snap-fit ​​portion 20121 toward the connecting portion 2011 falls within the range of the connecting portion 2011. The connection between the sub-snap-fit ​​portion 20121 and the connecting portion 2011 forms a snap-fit ​​surface. The end of the pair of sub-snap-fit ​​portions 20121 away from the connecting portion 2011 is provided with a chamfer. It is understood that in this embodiment, by setting the snap-fit ​​portion 2012 as a pair of sub-snap-fit ​​portions 20121 arranged back-to-back on the XY plane, and making the orthographic projection portion of the sub-snap-fit ​​portions 20121 towards the connecting portion 2011 fall within the range of the connecting portion 2011, the snap-fit ​​surfaces of the two sub-snap-fit ​​portions 20121 can form a symmetrical limiting of the connecting piece 3, improve the uniformity of the force on the snap-fit ​​structure, and avoid the connecting piece 3 from local deformation due to unilateral force. At the same time, a chamfer is provided at the end of the sub-snap-fit ​​portion 20121 away from the connecting portion 2011, which can play a guiding role in the assembly process of the buckle 201 passing through the through hole 301 of the connecting piece 3, reduce assembly resistance, improve assembly efficiency, and also prevent sharp edges from scratching and damaging the connecting piece 3.

[0049] In one embodiment, such as Figure 2As shown, in the XY plane, there is a gap 'a' between the outer wall of the connecting part 2011 and the wall of the through hole 301, where 'a' ranges from 1mm to 3mm. It can be understood that by limiting the gap 'a' between the outer wall of the connecting part 2011 and the wall of the through hole 301 to a reasonable range of 1mm to 3mm, this embodiment ensures smooth assembly of the snap-fit ​​201, avoids excessive occupation of the internal space of the battery cell, and guarantees the strength of the snap-fit ​​structure. This effectively suppresses deformation of the connecting piece 3 under external force, prevents gaps or breaks in the connecting part 2011, thereby ensuring stable current transmission in the battery cell and improving the safety and service life of the battery cell. It is understandable that if the interval a is less than 1mm, the gap between the connecting part 2011 and the through hole 301 will be too small, which will increase the assembly resistance of the buckle 201 passing through the through hole 301, reduce the assembly efficiency, and may even cause damage to the edge of the through hole 301 of the connecting piece 3 or the buckle 201. If the interval a is greater than 3mm, it will not only occupy additional internal space of the battery cell, but also require increasing the thickness of the snap-fit ​​part 2012 to ensure the snap-fit ​​limiting effect, thereby occupying the height space of the battery cell in the Z direction. If the thickness of the snap-fit ​​part 2012 is not increased, the snap-fit ​​structure will be insufficient in strength, making it difficult to effectively constrain the displacement and deformation of the connecting piece 3.

[0050] It is understandable that the value of 'a' can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, or any value between the two.

[0051] In one embodiment, such as Figure 2 As shown, on the XY plane, the width of the portion of the snap-fit ​​part 2012 that snaps into the lower surface of the connecting piece 3 is b, and the value of b ranges from 0.5mm to 3mm. It can be understood that by limiting the width b of the portion of the snap-fit ​​part 2012 that snaps into the lower surface of the connecting piece 3 within the reasonable range of 0.5mm to 3mm, this embodiment can ensure the stability of the snap-fit ​​structure, effectively suppress the risk of deformation of the connecting piece 3, and also take into account the ease of assembly and the compact layout of the internal space of the battery cell. It is understandable that if the width b is less than 0.5mm, the contact area between the snap-fit ​​part 2012 and the connecting piece 3 is too small, the fixing strength of the snap-fit ​​structure is insufficient, and it is difficult to effectively restrain the displacement and deformation of the connecting piece 3 when it is pulled by external force. This can easily lead to gaps or breakage at the connection part 2011 between the connecting piece 3 and the pole post 7 and the pole tab 601. If the width b is greater than 3mm, it will not only occupy additional internal space of the battery cell, but also make it difficult for the snap-fit ​​part 2012 to pass smoothly through the through hole 301 of the connecting piece 3 due to its large size, which will reduce assembly efficiency and may even cause damage to the edge of the through hole 301 or the snap 201.

[0052] It is understandable that the value of b can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value between the two.

[0053] In one embodiment, such as Figures 1 to 4 As shown, the upper surface of the cover plate 1 protrudes away from the lower plastic 2 to form a convex 101, and the convex 101 forms a receiving groove 102 on the lower surface of the cover plate 1; the lower plastic 2 is provided with a clearance hole 202; the battery cell cover plate assembly also includes a thermal pad 4, at least a portion of which passes through the clearance hole 202 and is sandwiched between the bottom of the receiving groove 102 and the upper surface of the connecting piece 3. It can be understood that by providing the convex 101 on the cover plate 1, this embodiment can form a receiving groove 102 that matches the convex 101 on the lower surface of the cover plate 1 without affecting the overall compact layout of the battery cell. The clearance hole 202 of the lower plastic 2 provides a precise and stable installation space for the thermal pad 4, so that the thermal pad 4 can be firmly sandwiched between the bottom of the receiving groove 102 and the upper surface of the connecting piece 3. Secondly, with the help of the thermal pad 4, the heat generated by the current transmission of the connecting piece 3 can be quickly conducted to the protrusion 101. The protrusion 101 can increase the contact area between the cover plate 1 and the external environment, which can accelerate heat dissipation and prevent heat from accumulating at the connection between the connecting piece 3 and the tab 601, thus meeting the requirements of high charge and discharge rates. In addition, since the connecting piece 3 in this embodiment does not easily deform, the thermal pad 4 can always maintain a good fit with the connecting piece 3 and the bottom of the receiving groove 102, thereby ensuring the continuous smoothness of the heat conduction path.

[0054] Specifically, the material of the thermal pad 4 can be, 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).

[0055] Furthermore, such as Figure 2 As shown, in the XY plane, there is a gap c between the outer wall of the thermal pad 4 and the wall of the clearance hole 202, where c ranges from 0.5mm to 3mm. It can be understood that this embodiment limits the gap c between the outer wall of the thermal pad 4 and the wall of the clearance hole 202 to within the range of 0.5mm to 3mm. This provides sufficient tolerance for errors during the battery cell assembly process, effectively compensating for processing and assembly errors between the cover plate 1, the lower plastic 2, and the thermal pad 4, preventing contact and compression between the thermal pad 4 and the wall of the clearance hole 202 due to dimensional deviations. Simultaneously, it also prevents the thermal pad 4 from shifting due to excessive gap, thus avoiding loss of stable support for the connecting piece 3. This ensures that the thermal pad 4 always adheres to the bottom of the receiving groove 102 and the upper surface of the connecting piece 3, ensuring unobstructed heat conduction and maintaining good heat dissipation. In addition, this gap can also reserve buffer space for thermal expansion and contraction, preventing the deformation of various components caused by temperature changes during the operation of the battery cell from interfering with each other, and further improving the structural stability and durability of the battery cell cover assembly.

[0056] It is understandable that the value of c can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value between the two.

[0057] Furthermore, such as Figure 2 As shown, along the Z direction, the thickness of the thermal pad 4 is d, and the value of d ranges from 1mm to 3mm. The thickness of the thermal pad 4 is greater than the thickness of the portion of the lower plastic 2 sandwiched between the cover plate 1 and the connecting piece 3. On the one hand, the thickness design of 1mm to d to 3mm ensures that the thermal pad 4 has sufficient heat conduction cross-sectional area to efficiently transfer heat at the connecting piece 3 and avoid local heat accumulation. On the other hand, the thickness of the thermal pad 4 is greater than the corresponding thickness of the lower plastic 2, which allows the thermal pad 4 to form a pre-tightening force after assembly, tightly clamping it between the bottom of the receiving groove 102 and the upper surface of the connecting piece 3, eliminating the gap at the heat conduction interface and ensuring the smooth flow of heat conduction path.

[0058] It is understandable that the value of d can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value between the two.

[0059] According to an embodiment of the present invention, on the other hand, such as Figure 1 , Figure 3 as well as Figure 4 As shown, a battery cell is also provided, including: a housing 5, an electrode group 6, the aforementioned battery cell cover assembly, and a terminal post 7.

[0060] Specifically, along the Z direction, one end of the housing 5 has an opening; the electrode group 6 is disposed inside the housing 5, and the end of the electrode group 6 near the opening is provided with an electrode tab 601; the cover plate 1 is placed over the opening, and the lower plastic 2 is located inside the housing 5; one end of the electrode post 7 is located inside the housing 5, and the other end passes through the cover plate and is located outside the housing 5; one end of the connecting piece 3 is electrically connected to the part of the electrode post 7 located inside the housing 5, and the other end is electrically connected to the electrode tab 601.

[0061] In this embodiment, the battery cell utilizes a snap-fit ​​structure between the buckle 201 and the through hole 301 to securely limit the position of the connecting piece 3. This effectively restricts the displacement and deformation of the connecting piece 3 when the battery cell is subjected to external forces, preventing gaps or even breakage at the connection point 2011 between the connecting piece 3 and the pole post 7 or the pole tab 601 caused by the pulling of the pole group 6 or the tab 601. At the same time, it ensures the stability of the current transmission inside the battery cell. From a structural perspective, it solves the safety hazards caused by the deformation of the connecting piece 3 in traditional battery cells, improves the safety and service life of the battery cell, and the structure is compact, without taking up too much internal space of the battery cell, thus balancing the energy density and reliability of the battery cell.

[0062] Preferably, the tab 601 is located on the lower surface of the connecting piece 3.

[0063] In one embodiment, such as Figure 1 , Figure 3 as well as Figure 4 As shown, the electrode post 7 includes a positive electrode post and a negative electrode post spaced apart along the X direction; the electrode tab 601 is located between the positive electrode post and the negative electrode post, and the electrode tab 601 includes a positive electrode tab and a negative electrode tab spaced apart along the X direction; the connecting piece 3 is a pair, one connecting piece 3 connects the positive electrode tab and the positive electrode post, and the other connecting piece 3 connects the negative electrode tab and the negative electrode post; the lower plastic 2 is provided with clearance holes 202 corresponding to the pair of connecting pieces 3, and the battery cell also includes a pair of thermal pads 4 corresponding to the pair of connecting pieces 3, the thermal pads 4 are clamped between the upper surface of the corresponding connecting piece 3 and the lower surface of the cover plate 1 through the corresponding clearance holes 202. It is understood that in this embodiment, by configuring the electrode post 7, electrode tab 601, connecting piece 3, clearance hole 202 and thermal pad 4 as a pair, the positive electrode post and positive electrode tab, and the negative electrode post and negative electrode tab are electrically connected through independent connecting pieces 3. Each connecting piece 3 is equipped with a set of clearance holes 202 and thermal pad 4. On the one hand, it can realize the independent transmission of positive and negative current, effectively avoid the risk of current crosstalk between positive and negative electrodes, and greatly improve the electrical safety of the battery cell. On the other hand, the one-to-one configuration of thermal pad 4 can conduct and dissipate heat at the positive and negative electrode connecting pieces in a targeted manner, ensuring that the heat dissipation effect of the positive and negative electrode connecting pieces is balanced and consistent.

[0064] The technical effects of the present invention will be described below with reference to some embodiments and comparative examples.

[0065] Table 1

[0066]

[0067] 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 all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A cell cover assembly, characterized in that, include: Cover plate; The lower plastic part, along the Z direction, is located on the lower surface of the cover plate, and a buckle is provided on the lower surface of the lower plastic part; The connecting piece, along the Z direction, is located on one side of the lower surface of the lower plastic and has a through hole extending along the Z direction; along the Z direction, the lower end of the buckle passes through the through hole and engages with the lower surface of the connecting piece; The buckle includes a connecting part and a snap-fit ​​part. Along the Z direction, one end of the connecting part is connected to the lower surface of the lower plastic, and at least part of the connecting part passes through the through hole. The snap-fit ​​part is located at the other end of the connecting part in the Z direction and is located outside the through hole. The snap-fit ​​part snaps into the lower surface of the connecting piece. On the XY plane, the width of the connecting part is smaller than the width of the snap-fit ​​part, and the connection between the snap-fit ​​part and the connecting part forms a snap-fit ​​surface that snaps into the lower surface of the connecting piece; The snap-fit ​​portion includes a pair of sub-snap-fit ​​portions that are back-to-back and spaced apart on the XY plane. Along the Z direction, the orthographic projection of the sub-snap-fit ​​portions toward the connecting portion partially falls within the range of the connecting portion. The connection between the sub-snap-fit ​​portions and the connecting portion forms the snap-fit ​​surface. The upper surface of the cover plate protrudes in a direction away from the lower plastic to form a bulge, and the bulge forms a receiving groove on the lower surface side of the cover plate; the lower plastic is provided with a clearance hole; the battery cell cover plate assembly also includes a thermal pad, at least a portion of which passes through the clearance hole and is sandwiched between the bottom of the receiving groove and the upper surface of the connecting piece. On the XY plane, there is a gap c between the outer wall of the thermal pad and the wall of the clearance hole, where the value of c ranges from 0.5mm to 3mm. Along the Z direction, the thickness of the thermal pad is d, and the value of d is in the range of 1mm≤d≤3mm; the thickness of the thermal pad is greater than the thickness of the portion of the lower plastic sandwiched between the cover plate and the connecting piece.

2. The cell cover assembly according to claim 1, characterized in that, The end of each of the sub-connectors away from the connecting part is chamfered.

3. The cell cover assembly according to claim 1, characterized in that, On the XY plane, there is a gap 'a' between the outer wall of the connecting part and the wall of the through hole, and the value of 'a' is in the range of 1mm ≤ a ≤ 3mm.

4. The cell cover assembly according to claim 1, characterized in that, On the XY plane, the width of the part that engages with the lower surface of the connecting piece is b, and the value of b ranges from 0.5mm to 3mm.

5. 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 4, wherein the cover is disposed over the opening, and the lower plastic is located inside the housing; The pole has one end located inside the housing and the other end passing through the cover plate and located outside the housing; One end of the connecting piece is electrically connected to the portion of the pole located inside the housing, and the other end is electrically connected to the tab.

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