Battery cell cover plate assembly and battery cell

Abstract

The invention 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, and a groove is formed in the lower surface of the cover plate in the Z direction; the lower plastic is located on the lower surface of the cover plate, and a first glue injection hole communicated with a groove opening of the groove is formed in the lower plastic; the connecting piece is located on one side of the lower surface, in the Z direction, of the lower plastic and provided with a second glue injection hole communicated with the first glue injection hole, and the groove, the first glue injection hole and the second glue injection hole are filled with insulating glue layers. The groove is formed in the lower surface of the cover plate, the first glue injection hole of the lower plastic and the second glue injection hole of the connecting piece are communicated with the groove, and the insulating glue layers are filled in the groove, the lower plastic and the second glue injection hole of the connecting piece and the groove and can stably support and limit the connecting piece; the traction stress of the pole group or the pole lug to the connecting piece when the battery cell is subjected to external force is effectively dispersed, the connecting piece is prevented from deforming, and gaps or fractures at the welding positions of the connecting piece, the pole column and the pole lug are prevented.

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: The cover plate has a groove on its lower surface along the Z direction; The lower plastic is located on the lower surface of the cover plate, and the lower plastic has a first injection hole that communicates with the groove opening; The connecting piece is located on one side of the lower surface of the lower plastic in the Z direction, and is provided with a second injection hole that communicates with the first injection hole. The groove, the first injection hole and the second injection hole are filled with an insulating adhesive layer.

[0005] Beneficial Effects: This invention forms an integrated fixing structure of the cover plate, lower plastic, and connecting piece by creating a groove on the lower surface of the cover plate and connecting the first injection hole of the lower plastic and the second injection hole of the connecting piece to the groove, and filling the interior of all three with an insulating adhesive layer. On one hand, the insulating adhesive layer provides stable support and positioning for the connecting piece, effectively dispersing the tensile stress on the connecting piece from the electrode assembly or tabs when the battery cell is subjected to external force, preventing deformation of the connecting piece, and preventing gaps or breaks at the welds between the connecting piece and the electrode post or tab. On the other hand, the integrated adhesive structure enhances the overall structural strength of the battery cell cover plate assembly, improves the connection reliability between the connecting piece and the cover plate assembly, thereby ensuring the stability of the battery cell current transmission, extending the battery cell's service life, and improving the battery cell's safety in use.

[0006] In one alternative embodiment, the cross-sectional area of ​​the groove in the XY plane gradually increases from the opening of the groove to the bottom of the groove.

[0007] Beneficial effects: On the one hand, it provides ample and gradually increasing space for the injection of bonding adhesive, avoiding problems such as adhesive overflow and incomplete filling due to limited space during the injection process, ensuring the formation of a continuous and dense insulating adhesive layer in the groove, the first injection hole, and the second injection hole; on the other hand, this gradual structure can form an anchoring shape similar to an "inverted platform", increasing the contact area between the insulating adhesive layer and the inner wall of the groove, enhancing the bonding strength between the adhesive layer and the cover plate through mechanical interlocking, preventing the adhesive layer from peeling off from the groove when pulled by external force, and guiding the stress under the action of external force to be evenly distributed along the side wall of the groove, further improving the stable positioning effect of the insulating adhesive layer on the bonding piece, thereby avoiding the risk of deformation of the bonding piece due to pulling, and ensuring the structural reliability and service life of the battery cell.

[0008] In one optional embodiment, the groove is shaped like a frustum, and the angle between the groove wall and the central axis of the groove is A, where the value of A ranges from 10°mm≤A≤45°.

[0009] Beneficial effects: The frustum-shaped groove structure combined with an included angle design of 10° to 45° ensures 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 within this angle range can form a stable mechanical interlocking structure with the cured insulating glue layer, enhancing the bonding strength between the glue layer and the cover plate, further improving the support and limiting effect of the 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.

[0010] In one optional embodiment, along the Z direction, the thickness of the cover plate is a, and the value of a ranges from 1mm to 3mm; the groove depth is b, and the value of b ranges from 0.5mm to 0.75×a.

[0011] Beneficial effects: A thickness design of 1mm≤a≤3mm ensures sufficient structural strength of the cover plate to withstand external impacts and prevents 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. A groove depth limit of 0.5mm≤b≤0.75×a ensures sufficient space for the groove 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.

[0012] In one optional embodiment, along the Z direction, the second injection hole includes a first through hole and a second through hole that are connected. On the XY plane, the cross-sectional area of ​​the first through hole is larger than the cross-sectional area of ​​the second through hole. A stepped surface is provided at the connection between the first through hole and the second through hole. The second through hole is located on the side of the second injection hole that is close to the cover plate.

[0013] Beneficial effects: On the one hand, the stepped through-hole structure can create a gradient flow and temporary storage effect on the injected bonding adhesive, which can slow down the flow rate of the adhesive and avoid filling blind spots or air bubbles due to excessive flow rate, ensuring that the adhesive is evenly filled in the entire cavity of the groove, the first injection hole and the second injection hole; on the other hand, it can reduce the amount of bonding adhesive used while ensuring the injection efficiency, reduce production costs, achieve a balance between structural performance and economy, and ultimately avoid the risk of tensile deformation of the bonding piece from multiple dimensions, ensuring the structural reliability and service life of the battery cell.

[0014] 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.

[0015] 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, thus meeting the requirements of high-rate charging and discharging conditions.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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, ensuring the smoothness of the heat conduction path. At the same time, this pre-tightening structure can form a continuous and stable upward support force on the connecting piece, which works in conjunction with the limiting effect of the insulating adhesive layer to further disperse the stress generated by the pulling of the electrode group or electrode tab, effectively avoiding the risk of deformation of the connecting piece by external force, and ultimately improving the structural reliability of the cell cover assembly and the service life of the cell.

[0020] Secondly, the present invention also provides a battery cell, comprising: 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; In the aforementioned cell cover assembly, 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.

[0021] Beneficial effects: The battery cell provided by this invention integrates the above-mentioned battery cell cover plate assembly. With the help of the grooves and insulating adhesive layers filled in the injection holes on the cover plate, the lower plastic, and the connecting piece, a stable anchoring structure for the connecting piece is formed. This can effectively disperse the tensile stress on the connecting piece when the electrode group or electrode tab is subjected to external force, avoid deformation of the connecting piece, and prevent gaps or breaks at the welding joints of the connecting piece and the electrode post or electrode tab. At the same time, the coordinated design of the protrusion, the avoidance hole, and the heat-conducting pad in the cover plate assembly can quickly conduct the heat generated by current transmission at the connecting piece, avoiding the problem of aging of the insulating adhesive layer and performance degradation of the welding point caused by local high temperature.

[0022] In one optional embodiment, the electrode post includes a positive electrode post and a negative electrode post spaced apart along the X direction; the tab is located between the positive electrode post and the negative electrode post, and the tab includes a positive tab and a negative tab spaced apart along the X direction; the connecting piece is a pair, one of the connecting pieces connects the positive tab to the positive electrode post, and the other connecting piece connects the negative tab to the negative electrode post; the lower plastic is provided with clearance holes corresponding to the pair of connecting pieces, and the battery cell also includes a pair of thermal pads corresponding to the pair of connecting pieces, the thermal pads being clamped between the upper surface of the corresponding connecting piece and the lower surface of the cover plate through the corresponding clearance holes.

[0023] Beneficial effects: This invention configures the electrode post, electrode tab, connecting piece, clearance hole, and thermal pad as a pair, so that the positive electrode post and positive electrode tab, and the negative electrode post and negative electrode tab are electrically connected through independent connecting pieces. Each connecting piece is equipped with a set of clearance holes and thermal pads. 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 thermal pad configuration 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. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention; Figure 2 for Figure 1 The exploded view of the battery cell shown; Figure 3 for Figure 1A cross-sectional view of the battery cell shown. Figure 4 for Figure 3 A magnified view of part M; Figure 5 for Figure 3 A magnified view of N in the middle.

[0026] Explanation of reference numerals in the attached figures: 1. Cover plate; 101. Groove; 102. Protrusion; 2. Lower plastic; 201. First injection hole; 202. Clearance hole; 3. Connecting piece; 301. Second injection hole; 3011. First through hole; 3012. Second through hole; 4. Thermal pad; 5. Housing; 6. Electrode assembly; 601. Electrode tab; 7. Electrode post. Detailed Implementation

[0027] 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.

[0028] The following is combined Figures 1 to 5 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.

[0029] According to embodiments of the present invention, in one aspect, such as Figures 1 to 5 As shown, a battery cell cover assembly is provided, including: a cover plate 1, a lower plastic 2, and a connecting piece 3.

[0030] Specifically, along the Z direction, a groove 101 is provided on the lower surface of the cover plate 1; the lower plastic 2 is located on the lower surface of the cover plate 1, and a first injection hole 201 connected to the groove 101 is provided on the lower plastic 2; the connecting piece 3 is located on one side of the lower surface of the lower plastic 2 in the Z direction, and a second injection hole 301 connected to the first injection hole 201 is provided. The groove 101, the first injection hole 201 and the second injection hole 301 are filled with an insulating adhesive layer.

[0031] In this embodiment, a groove 101 is provided on the lower surface of the cover plate 1, and the first injection hole 201 of the lower plastic 2 and the second injection hole 301 of the connecting piece 3 are connected to the groove 101. An insulating adhesive layer is filled inside the three components, forming an integrated fixing structure of the cover plate 1, the lower plastic 2, and the connecting piece 3. On the one hand, the insulating adhesive layer can provide stable support and limit the connecting piece 3, effectively dispersing the tensile stress on the connecting piece 3 by the electrode group 6 or the electrode tab 601 when the battery cell is subjected to external force, preventing deformation of the connecting piece 3, and preventing gaps or breaks at the welding joints of the connecting piece 3 with the electrode post 7 and the electrode tab 601. On the other hand, the integrated adhesive structure can enhance the overall structural strength of the battery cell cover plate assembly, improve the connection reliability between the connecting piece 3 and the cover plate assembly, thereby ensuring the stability of the battery cell current transmission, extending the service life of the battery cell, and improving the safety of the battery cell.

[0032] In one embodiment, such as Figure 4 and Figure 5 As shown, the cross-sectional area of ​​groove 101 gradually increases from the opening to the bottom of groove 101 in the XY plane. This design provides ample and gradually increasing space for the injection of adhesive, preventing adhesive overflow and incomplete filling due to limited space during the injection process. This ensures a continuous and dense insulating adhesive layer is formed within groove 101, the first injection hole 201, and the second injection hole 301. Furthermore, this gradual structure creates an anchoring shape similar to an inverted platform, increasing the contact area between the insulating adhesive layer and the inner wall of groove 101. Mechanical interlocking enhances the bonding strength between the adhesive layer and the cover plate 1, preventing the adhesive layer from peeling off from groove 101 under external force. Simultaneously, it guides the stress under external force to be evenly distributed along the sidewall of groove 101, further improving the stability and positioning effect of the insulating adhesive layer on the connecting piece 3. This avoids the risk of deformation of the connecting piece 3 due to tension, ensuring the structural reliability and service life of the battery cell.

[0033] Furthermore, such as Figure 4 and Figure 5 As shown, the groove 101 is shaped like a frustum, and the angle between the groove wall and the central axis of the groove 101 is A, with A ranging from 10° to 45°. It can be understood that the frustum-shaped groove 101, combined with an angle design of 10° to 45°, ensures a smooth filling path during adhesive injection, avoiding problems such as obstructed adhesive flow and insufficient filling due to an excessively small angle, or difficulties in stamping due to an excessively large angle. Simultaneously, the groove wall within this angle range can form a stable mechanical interlocking structure with the cured insulating adhesive layer, enhancing the bonding strength between the adhesive layer and the cover plate 1, further improving the support and limiting effect of the adhesive layer on the connecting piece 3, effectively dispersing the stress generated by the pulling of the electrode group 6 or the electrode tab 601, 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.

[0034] It is understandable that the value of A can be 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45° or any value between the two.

[0035] In one embodiment, such as Figure 4 and Figure 5 As shown, along the Z direction, the thickness of the cover plate 1 is 'a', with a value ranging from 1mm ≤ a ≤ 3mm; the groove depth of the groove 101 is 'b', with a value ranging from 0.5mm ≤ b ≤ 0.75 × a. It can be understood that the thickness design of 1mm ≤ a ≤ 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 between the connecting piece 3 and the tab 601. The groove depth limitation of 0.5mm ≤ b ≤ 0.75 × a ensures that the groove 101 has sufficient space to accommodate the adhesive, allowing for the filling of a sufficient amount of insulating adhesive to form a stable anchoring structure and enhancing the bonding strength between the insulating adhesive layer and the cover plate 1. It also prevents excessive groove depth from penetrating the cover plate 1 or weakening its structural load-bearing capacity, thus preventing the risk of cracking in the cover plate 1.

[0036] It is understandable that the value of 'a' can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, or any value between the two.

[0037] In one embodiment, such as Figure 4 and Figure 5 As shown, along the Z-direction, the second injection hole 301 includes a first through hole 3011 and a second through hole 3012 that are connected. In the XY plane, the cross-sectional area of ​​the first through hole 3011 is larger than that of the second through hole 3012. A stepped surface is provided at the connection between the first through hole 3011 and the second through hole 3012. The second through hole 3012 is located on the side of the second injection hole 301 closer to the cover plate 1. It can be understood that, on the one hand, the stepped through hole structure can form a gradient guiding and temporary storage effect on the injected bonding adhesive, which can slow down the flow rate of the adhesive and avoid filling blind spots or air bubbles due to excessive flow rate, ensuring that the adhesive is evenly filled in the entire cavity of the groove 101, the first injection hole 201, and the second injection hole 301; on the other hand, it can reduce the amount of bonding adhesive used while ensuring injection efficiency, reduce production costs, achieve a balance between structural performance and economy, and ultimately avoid the risk of tensile deformation of the bonding piece 3 from multiple dimensions, ensuring the structural reliability and service life of the battery cell.

[0038] In one embodiment, such as Figures 1 to 4As shown, the upper surface of the cover plate 1 protrudes away from the lower plastic 2 to form a convex 102, and the convex 102 forms a receiving groove on the lower surface side 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 and the upper surface of the connecting piece 3. It can be understood that by providing the convex 102 on the cover plate 1, this embodiment can form a receiving groove adapted to the convex 102 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 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 102. The protrusion 102 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, thereby ensuring the continuous smoothness of the heat conduction path.

[0039] 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).

[0040] It should be noted that the reason why the thermal pad 4 can conduct heat quickly is because the area on the other side of the connecting piece 3 and the thermal pad 4 in the Z direction is the connection area between the connecting piece 3 and the tab 601.

[0041] Furthermore, such as Figure 4 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 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.

[0042] 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.

[0043] Furthermore, such as Figure 4 As shown, along the Z direction, the thickness of the thermal pad 4 is d, and the value of d is in the range of 1mm≤d≤3mm; the thickness of the thermal pad 4 is greater than the thickness of the part of the lower plastic 2 sandwiched between the cover plate 1 and the connecting piece 3. Understandably, on the one hand, the thickness design of 1mm≤d≤3mm ensures that the thermal pad 4 has sufficient heat conduction cross-sectional area to efficiently transfer heat at the connecting piece 3, avoiding local heat accumulation, and also prevents the overall size of the cell cover assembly from increasing due to excessive thickness, meeting the design requirements of cell miniaturization. On the other hand, the design that the thickness of the thermal pad 4 is greater than the corresponding thickness of the lower plastic 2 allows the thermal pad 4 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 3, eliminating the gap at the heat conduction interface, ensuring the smoothness of the heat conduction path. At the same time, this pre-tightening structure can form a continuous and stable upward support force on the connecting piece 3, which works in conjunction with the limiting effect of the insulating adhesive layer to further disperse the stress generated by the pulling of the electrode group 6 or the electrode tab 601, effectively avoiding the risk of deformation of the connecting piece 3 by external force, and ultimately improving the structural reliability of the cell cover assembly and the service life of the cell.

[0044] It is understandable that the value of d can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm or any value between the two.

[0045] According to an embodiment of the present invention, another aspect provides a battery cell, comprising: a housing 5, an electrode group 6, the aforementioned battery cell cover assembly, and a terminal post 7.

[0046] 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 1 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.

[0047] The battery cell provided in this embodiment integrates the aforementioned battery cell cover assembly. With the help of the groove 101 on the cover plate 1, the lower plastic 2, and the insulating adhesive layer filled in the injection hole, a stable anchoring structure for the connecting piece 3 is formed. This can effectively disperse the tensile stress on the connecting piece 3 when the electrode group 6 or the electrode tab 601 is subjected to external force, prevent the connecting piece 3 from deforming, and prevent gaps or breaks at the welding joints of the connecting piece 3 with the electrode post 7 and the electrode tab 601. At the same time, the coordinated design of the protrusion 102, the clearance hole 202, and the heat-conducting pad 4 in the cover assembly can quickly conduct the heat generated by current transmission at the connecting piece 3, avoiding the problem of aging of the insulating adhesive layer and performance degradation of the welding point caused by local high temperature.

[0048] Preferably, the tab 601 is located on the lower surface of the connecting piece 3.

[0049] It should be noted that the electrical connection in this embodiment can be, but is not limited to, welding or conductive adhesive connection.

[0050] In one embodiment, the electrode post 7 includes a positive electrode post and a negative electrode post spaced apart along the X direction; the electrode tab 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 being 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.

[0051] The technical effects of the present invention will be described below with reference to some embodiments and comparative examples.

[0052] Table 1

[0053] 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 groove on its lower surface along the Z direction; The lower plastic is located on the lower surface of the cover plate, and the lower plastic has a first injection hole that communicates with the groove opening; The connecting piece is located on one side of the lower surface of the lower plastic in the Z direction, and is provided with a second injection hole that communicates with the first injection hole. The groove, the first injection hole and the second injection hole are filled with an insulating adhesive layer.

2. The cell cover assembly according to claim 1, characterized in that, From the opening of the groove to the bottom of the groove, the cross-sectional area of ​​the groove on the XY plane gradually increases.

3. The cell cover assembly according to claim 2, characterized in that, The groove is shaped like a frustum, and the angle between the groove wall and the central axis of the groove is A, with the value of A ranging from 10° to 45°.

4. The cell cover assembly according to claim 1, characterized in that, Along the Z direction, the thickness of the cover plate is a, and the value of a is in the range of 1mm≤a≤3mm; the groove depth is b, and the value of b is in the range of 0.5mm≤b≤0.75×a.

5. The cell cover assembly according to claim 1, characterized in that, Along the Z direction, the second injection hole includes a first through hole and a second through hole that are connected. On the XY plane, the cross-sectional area of ​​the first through hole is larger than the cross-sectional area of ​​the second through hole. A stepped surface is provided at the connection between the first through hole and the second through hole. The second through hole is located on the side of the second injection hole that is close to the cover plate.

6. The cell cover assembly according to claim 1, characterized in that, The upper surface of the cover plate protrudes 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.

7. The cell cover assembly according to claim 6, characterized in that, 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.

8. The cell cover assembly according to claim 6, characterized in that, 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.

9. 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 8, 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.

10. The battery cell according to claim 9, characterized in that, The electrode post includes a positive electrode post and a negative electrode post spaced apart along the X direction; the tab is located between the positive electrode post and the negative electrode post, and the tab includes a positive tab and a negative tab spaced apart along the X direction; the connecting piece is a pair, one of the connecting pieces connects the positive tab to the positive electrode post, and the other connecting piece connects the negative tab to the negative electrode post; the lower plastic is provided with clearance holes corresponding to the pair of connecting pieces, and the battery cell also includes a pair of thermal pads corresponding to the pair of connecting pieces, the thermal pads being clamped between the upper surface of the corresponding connecting piece and the lower surface of the cover plate through the corresponding clearance holes.

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