Cover plate assembly, battery cell and battery pack

Abstract

The utility model provides a cover plate assembly, a battery cell and a battery pack, and relates to the technical field of batteries. The cover plate assembly comprises an end cover, a pole, a bottom plate and a sealing ring; the pole comprises a first section and a second section which are connected with each other, the diameter of the second section is smaller than that of the first section, the first section is provided with a first shaft shoulder surface facing the second section, and the first section is arranged on the end cover in a penetrating manner; the bottom plate sleeves one end, far away from the first section, of the second section; the sealing ring sleeves the second section, is positioned between the end cover and the bottom plate, and is provided with a first end surface deviating from the bottom plate; the inner diameter side of the first end face abuts against the first shaft shoulder face. According to the cover plate assembly, the pole comprises the first section and the second section which are different in diameter, the end face of the sealing ring can abut against the first shaft shoulder face between the first section and the second section, and therefore a sealing face can be formed between the sealing ring and the pole on the basis that the sealing face is formed between the sealing ring and the bottom plate and the sealing face is formed between the sealing ring and the end cover, and the sealing performance of the cover plate assembly is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a cover plate assembly, a battery cell and a battery pack. BACKGROUND

[0002] In the related art, the cover plate assembly includes an end cover, a pole post arranged in the end cover, and a sealing ring for sealing the fitting part between the pole post and the end cover. The sealing ring has poor sealing performance for the fitting part between the pole post and the end cover. CONTENT OF THE UTILITY MODEL

[0003] Embodiments of the present application provide a cover plate assembly, a battery cell and a battery pack, which can improve the sealing performance of the fitting part between the pole post and the cover plate.

[0004] In a first aspect, embodiments of the present application provide a cover plate assembly, which includes an end cover, a pole post, a bottom plate and a sealing ring. The pole post includes a first segment and a second segment connected to each other, the diameter of the second segment is smaller than that of the first segment, the first segment has a first shaft shoulder surface facing the second segment, and the first segment is arranged in the end cover. The bottom plate is sleeved on an end of the second segment away from the first segment. The sealing ring is sleeved on the second segment and located between the end cover and the bottom plate, and has a first end surface facing away from the bottom plate. The inner diameter side of the first end surface is in abutment with the first shaft shoulder surface.

[0005] Optionally, the sealing ring further has a second end surface facing the bottom plate, and a groove is arranged on the first end surface and / or the second end surface.

[0006] Optionally, the groove extends in a ring shape along the circumference of the sealing ring.

[0007] Optionally, the width dimension of the groove gradually decreases in a direction close to the groove bottom.

[0008] Optionally, the outer diameter of the first segment is d1, and the inner diameter of the sealing ring is d2, and d1≥d2+0.6mm is satisfied.

[0009] Optionally, the pole post further includes a third segment, the third segment is connected to an end of the second segment away from the first segment, and the diameter of the third segment is smaller than that of the second segment. The second segment has a second shaft shoulder surface facing the third segment, and the bottom plate is sleeved on the third segment and in abutment with the second shaft shoulder surface.

[0010] Optionally, a fitting through hole is arranged on the bottom plate, the third segment is arranged in the fitting through hole and connected to the bottom plate.

[0011] Optionally, the depth dimension of the fitting through hole is H0, and the height dimension of the third segment is H1, and H0≥H1+0.1mm is satisfied.

[0012] Optionally, a sink is arranged on the side of the bottom plate away from the end cover, and the matching through hole penetrates the bottom wall of the sink; wherein the depth dimension of the sink is H2, and 0.1mm≤H2≤0.6mm is satisfied; and / or, the diameter of the matching through hole is d3, the diameter of the sink is d4, and d3+0.8mm≤d4≤d3+3mm is satisfied.

[0013] Optionally, the pole post further comprises a terminal, the terminal is located on the side of the end cover away from the sealing ring, the terminal is connected with the first section away from the second section, and the outer diameter of the terminal is greater than the outer diameter of the first section.

[0014] Optionally, the material of the terminal is different from the material of the first section.

[0015] Optionally, the first section extends radially outward to form a support portion at the end close to the terminal, and the support portion is connected with the terminal.

[0016] In a second aspect, the embodiments of the present application provide an electric core, which comprises a shell, an electrode assembly and the aforementioned cover plate assembly; the shell has a receiving cavity; the electrode assembly is arranged in the receiving cavity; the end cover is combined with the shell, and the electrode assembly is connected with the bottom plate.

[0017] In a third aspect, the embodiments of the present application provide a battery pack, which comprises the aforementioned electric core, and there are multiple electric cores, and the multiple electric cores are electrically connected.

[0018] The embodiments of the present application have the following beneficial effects:

[0019] In the embodiments of the present application, by making the pole post comprise the first section and the second section with different diameters, the end surface of the sealing ring can abut against the first shoulder surface between the first section and the second section, so that a sealing surface can be formed between the sealing ring and the pole post on the basis of the sealing surface formed between the sealing ring and the bottom plate and the end cover. In this way, when there is a leakage channel at the matching part between the bottom plate and the pole post, the sealing surface between the sealing ring and the pole post can be used to block the leakage channel, so that the internal medium of the electric core can be effectively prevented from leaking from the matching part between the pole post and the end cover, and the sealing performance of the cover plate assembly can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0021] Figure 1 is a structural schematic diagram of a cover plate assembly in the related art;

[0022] Figure 2is a structural schematic view of a cover plate assembly provided by an embodiment of the present application;

[0023] Figure 3 is Figure 2 is an enlarged view of A in FIG. 1;

[0024] Figure 4 is a structural schematic view of a pole provided by an embodiment of the present application;

[0025] Figure 5 is a sectional view of a sealing ring provided by an embodiment of the present application;

[0026] Figure 6 is a structural schematic view of a sealing ring provided by an embodiment of the present application;

[0027] Figure 7 is a sectional view of a bottom plate provided by an embodiment of the present application;

[0028] Figure 8 is Figure 2 is an enlarged view of B in FIG. 1;

[0029] Figure 9 is a structural schematic view of an electric core provided by an embodiment of the present application;

[0030] Figure 10 is a structural schematic view of a battery pack provided by an embodiment of the present application.

[0031] Legend of Reference Signs:

[0032] 1 - cover plate assembly; 11 - end cover;

[0033] 12 - pole; 121 - first section; 122 - second section; 123 - third section; 124 - first shoulder surface; 125 - terminal; 126 - support portion; 127 - second shoulder surface;

[0034] 13 - bottom plate; 131 - mating through hole; 132 - sink;

[0035] 14 - sealing ring; 141 - first end surface; 142 - second end surface; 143 - groove;

[0036] 15 - upper plastic part; 16 - lower plastic part;

[0037] 2 - electric core; 21 - shell; 22 - electrode assembly; 23 - accommodating cavity;

[0038] 3 - battery pack; 31 - box body; 32 - box cover; 33 - electric core. DETAILED DESCRIPTION

[0039] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts are within the scope of the present application.

[0040] In the description of the present application, it should be noted that unless specifically defined and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] The term "comprising" or "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that the product including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such product.

[0042] In the description of the embodiments of the present application, the words "example" or "for example" are used to represent example, illustration or description. Any embodiment or design scheme described as "example" or "for example" in the embodiments of the present application is not interpreted as more preferred or having more advantages than another embodiment or design scheme. The words "example" or "for example" are intended to present relative concepts in a clear manner.

[0043] Before introducing the cover plate assembly 1, the electric cell 2 and the battery pack 3 provided by the embodiments of the present application, the related art of the present application is introduced.

[0044] As shown in Figure 1 In the related art, the cover plate assembly 1 includes an end cover 11, a pole 12 penetrating the end cover 11, and a sealing ring 14 sealing the matching part between the pole 12 and the end cover 11. The pole 12 is a T-shaped pole 12, which includes a large-diameter section and a small-diameter section connected together. The small-diameter section penetrates the end cover 11, and the large-diameter section is located on the side of the end cover 11 away from the electrode assembly 22 of the electric cell 2. The end of the small-diameter section faces the electrode assembly and is connected with the bottom plate 13, as shown in Figure 1As shown. The sealing ring 14 is located between the base plate 13 and the end cap 11 and is under axial pressure, thus forming two sealing surfaces: one between the sealing ring 14 and the base plate 13, and the other between the sealing ring 14 and the end cap 11. However, the sealing ring 14 lacks a sealing effect at the connection between the base plate 13 and the electrode post 12. If there is a defect in the connection between the base plate 13 and the electrode post 12, a leakage point can easily form at the mating part between the electrode post 12 and the base plate 13, resulting in leakage of the battery cell 2 between the end cap 11 and the electrode post 12. The leakage path of the internal medium of the battery cell 2 is as follows. Figure 1 As indicated by the middle arrow. Therefore, to ensure the sealing performance of the cover assembly 1, the reliability requirements for the connection between the pole post 12 and the base plate 13 are high, resulting in high connection costs. Furthermore, the connection quality between the pole post 12 and the base plate 13 is difficult to monitor, and the connection process yield cannot be guaranteed to be 100%. In addition, if there are defects in the connection between the pole post 12 and the base plate 13, they are not easy to detect.

[0045] Based on this, embodiments of this application provide a cover plate assembly 1, a battery cell 2, and a battery pack 3, which can improve the sealing performance of the mating parts between the end cover 11 and the terminal post 12, so as to avoid the problem of poor sealing effect caused by poor connection between the terminal post 12 and the base plate 13.

[0046] The following combination Figures 2 to 10 The present application provides a detailed description of the cover plate assembly 1, the battery cell 2, and the battery pack 3 provided in the embodiments of this application.

[0047] Please see Figures 2 to 4 , Figure 2 This is a schematic diagram of the structure of the cover plate assembly 1 provided in an embodiment of this application. Figure 3 yes Figure 2 Enlarged view of point A in the middle. Figure 4 This is a schematic diagram of the structure of the pole post 12 provided in an embodiment of this application. An embodiment of this application provides a cover plate assembly 1. The cover plate assembly 1 includes an end cap 11, a pole post 12, a base plate 13, and a sealing ring 14. The pole post 12 includes a first segment 121 and a second segment 122 connected together. The diameter of the second segment 122 is smaller than the diameter of the first segment 121. The first segment 121 has a first shoulder surface 124 facing the second segment 122. The first segment 121 passes through the end cap 11. The base plate 13 is sleeved on the end of the second segment 122 away from the first segment 121. The sealing ring 14 is sleeved on the second segment 122 and located between the end cap 11 and the base plate 13. The sealing ring 14 has a first end face 141 facing away from the base plate 13. The inner diameter side of the first end face 141 abuts against the first shoulder surface 124 between the first segment 121 and the second segment 122.

[0048] Specifically, the bottom plate 13 is sleeved on the pole 12 and connected or riveted with the pole 12. The connection between the bottom plate 13 and the second section 122 can be that the bottom plate 13 is directly fixed on the second section 122, or the bottom plate 13 is fixed on the second section 122 through other components or structures. For example, the bottom plate 13 can be fixed on the second section 122 through the third section 123, and the third section 123 is connected with the second section 122 away from the first section 121. Alternatively, the third section 123 is integrally formed with the second section 122.

[0049] It can be understood that the first shoulder surface 124 refers to the position where the cross-sectional dimension or the radial dimension of the stepped shaft changes. Correspondingly, in the embodiment, the first shoulder surface 124 is the position where the radial dimension changes between the first section 121 and the second section 122, and is the end surface of the first section 121 facing the second section 122. The first shoulder surface 124 extends around the axis of the pole 12 to be annular.

[0050] It can be understood that the sealing ring 14 is interference fitted between the bottom plate 13 and the end cover 11, so that the sealing ring 14 is in an axially compressed state, thereby forming a sealing surface between the end surface of the sealing ring 14 facing the end cover 11 and the end surface of the sealing ring 14 facing the bottom plate 13. Figure 3 It can be understood that the interference between the bottom end of the sealing ring 14 and the top of the bottom plate 13 is to illustrate that the sealing ring 14 is interference fitted between the bottom plate 13 and the end cover 11.

[0051] It can be understood that the first section 121 and the second section 122 are coaxially arranged.

[0052] Exemplarily, the first section 121 and the second section 122 are integrally formed.

[0053] It can be understood that the cover plate assembly 1 can further include an upper plastic part 15 and a lower plastic part 16. The lower plastic part 16 is arranged on the side of the end cover 11 facing the bottom plate 13, and the lower plastic part 16 is used to insulate and isolate the end cover 11 from the bottom plate 13, the electrode assembly 22 and other components inside the battery cell 2 and not required to be electrically connected with the end cover 11. The upper plastic part 15 is arranged on the side of the end cover 11 away from the bottom plate 13, and the upper plastic part 15 is located between the end cover 11 and the pole 12 (specifically, the upper plastic part 15 is located between the end cover 11 and the terminal 125). The upper plastic part 15 is used to insulate and isolate the pole 12 from the end cover 11.

[0054] In the embodiment, by setting the pole post 12 as the first section 121 and the second section 122 with different diameters, the end surface of the sealing ring 14 can abut against the first shaft shoulder surface 124 between the first section 121 and the second section 122, so that a sealing surface can be formed between the sealing ring 14 and the pole post 12 in addition to the sealing surface formed between the sealing ring 14 and the bottom plate 13 and the end cover 11. Thus, when there is a leakage channel at the joint between the bottom plate 13 and the pole post 12, the sealing surface between the sealing ring 14 and the pole post 12 can block the leakage channel, so as to effectively prevent the internal medium of the battery cell 2 from leaking from the joint between the pole post 12 and the end cover 11, thereby improving the sealing performance of the cover plate assembly 1.

[0055] Referring to Figure 5 , Figure 5 is a sectional view of the sealing ring 14 provided by the embodiment of the present application. In some embodiments, the sealing ring 14 also has a second end surface 142 facing the bottom plate 13, and the first end surface 141 and / or the second end surface 142 is provided with a groove 143.

[0056] Specifically, the first end surface 141 is provided with the groove 143, or the second end surface 142 is provided with the groove 143, or both the first end surface 141 and the second end surface 142 are provided with the groove 143.

[0057] It can be understood that the sealing ring 14 is installed in interference between the bottom plate 13 and the end cover 11, and the sealing ring 14 is deformed by extrusion to play a sealing role. However, the sealing ring 14 is axially compressed, and therefore needs to have a release space in other directions.

[0058] Based on this, in the embodiment, by providing the groove 143, a release space is provided for the compression deformation of the sealing ring 14, so as to accommodate the material moved by the sealing ring 14 due to extrusion through the groove 143, so that the sealing ring 14 is axially compressed in place, thereby improving the sealing effect between the sealing ring 14 and the end cover 11, the bottom plate 13 and the first shaft shoulder surface 124.

[0059] Exemplarily, the sealing ring 14 is an elastic member with a porous mesh structure. Specifically, the porous mesh structure does not affect the sealing requirement between the sealing ring 14 and the end cover 11 and the bottom plate 13. Moreover, the porous mesh structure needs to be observed clearly through a magnifying lens.

[0060] Referring to Figure 6 , Figure 6is a structural schematic view of the sealing ring 14 provided by the embodiments of the present application. In some embodiments, the groove 143 extends along the circumference of the sealing ring 14 in a ring shape. In this way, on the one hand, the axial compression amount of the sealing ring 14 can be improved; on the other hand, the structural symmetry of the sealing ring 14 can be improved to improve the stress uniformity of the sealing ring 14, so that the stress state of the sealing ring 14 can be improved and stress concentration can be improved. Finally, the sealing effect between the sealing ring 14 and the end cover 11, the bottom plate 13 and the first shaft shoulder surface 124 can be improved.

[0061] In some embodiments, the width dimension of the groove 143 gradually decreases along the direction close to the groove bottom of the groove 143. In this way, on the one hand, stress concentration can be reduced, and on the other hand, by reducing the size of the groove 143 close to the groove bottom, the sealing ring 14 has more material, so that the sealing ring has more material to bear the load. In this way, the strength of the sealing ring 14 can be improved to improve the load capacity of the sealing ring and facilitate the improvement of the service life of the sealing ring 14.

[0062] Exemplarily, the cross-sectional shape of the groove 143 can be V-shaped, U-shaped, semicircular, etc.

[0063] Please refer to Figure 4 In some embodiments, the outer diameter of the first section 121 is d1, and the inner diameter of the sealing ring 14 is d2, which satisfies: d1≥d2+0.6mm.

[0064] Exemplarily, the inner diameter of the first section 121 is d1, including but not limited to d2+0.6mm, d2+0.77mm, d2+0.94mm, d2+1.11mm, d2+1.28mm, d2+1.45mm, d2+1.62mm, d2+1.79mm, d2+1.96mm, d2+2.13mm, d2+2.3mm, d2+2.47mm, d2+2.64mm, d2+2.81mm, d2+2.98mm, d2+3.15mm, d2+3.32mm, d2+3.49mm, d2+3.66mm, d2+3.83mm, d2+4mm.

[0065] Exemplarily, the inner circumferential surface of the sealing ring 14 is in contact with the outer circumferential surface of the second section 122.

[0066] In the present embodiment, by the above limitation, the radial size of the minimum sealing surface between the sealing ring 14 and the first shaft shoulder surface 124 can be guaranteed, so that the sealing effect between the sealing ring 14 and the pole 12 can be guaranteed to facilitate the sealing reliability between the sealing ring 14 and the pole 12.

[0067] Please refer to Figure 3 and Figure 4In some embodiments, the pole 12 further comprises a third section 123. The third section 123 is connected to the end of the second section 122 away from the first section 121. The diameter of the third section 123 is smaller than that of the second section 122. The second section 122 has a second axial shoulder surface 127 facing the third section 123. The bottom plate 13 is sleeved on the third section 123 and abuts against the second axial shoulder surface 127. In this way, the installation position of the bottom plate 13 can be positioned by the second axial shoulder surface 127 between the second section 122 and the third section 123, so that the assembly efficiency of the cover plate assembly 1 can be improved.

[0068] In addition, by setting the diameter of the third section 123 to be smaller than that of the second section 122, the second axial shoulder surface 127 is formed at the end of the second section 122 facing the third section 123. In this way, the inner diameter of the bottom plate 13 can be made smaller than the inner diameter of the sealing ring 14, so that the end of the sealing ring 14 away from the end cover 11 abuts against the bottom plate 13. In this way, the contact area between the sealing ring 14 and the bottom plate 13 can be increased, the sealing surface area between the bottom plate 13 and the sealing ring 14 can be increased, and finally the sealing performance of the cover plate assembly 1 can be improved.

[0069] Please refer to Figure 3 In some embodiments, the bottom plate 13 is provided with a matching through hole 131, and the third section 123 is sleeved in the matching through hole 131 and connected to the bottom plate 13. It can be understood that the pole 12 is connected to the bottom plate 13, which can improve the connection strength between the pole 12 and the bottom plate 13 and the flow capacity between the pole 12 and the bottom plate 13.

[0070] Please refer to Figure 4 and Figure 7 , Figure 7 is a sectional view of the bottom plate 13 provided by the embodiments of the present application. In some embodiments, the depth dimension of the matching through hole 131 is H0, and the height dimension of the third section 123 is H1, which satisfies: H0≥H1+0.1mm.

[0071] It can be understood that the axis of the matching through hole 131 is perpendicular to the bottom plate 13, and the depth dimension H0 of the matching through hole 131 is consistent with the thickness dimension of the bottom plate 13.

[0072] Exemplarily, the depth dimension H0 of the matching through hole 131 includes but is not limited to H1+0.15mm, H1+0.32mm, H1+0.38mm, H1+0.45mm, H1+0.51mm, H1+0.58mm, H1+0.71mm, H1+0.75mm, H1+0.82mm, H1+0.87mm, H1+0.91mm, H1+1.02mm, H1+1.15mm, H1+1.23mm, H1+1.31mm, H1+1.38mm, H1+1.42mm, H1+1.53mm, H1+1.67mm, H1+1.72mm, H1+1.81mm, H1+1.95mm, H1+2mm.

[0073] It can be understood that the welding joint formed when the bottom plate 13 is connected with the pole 12 has a thickness and occupies a certain space.

[0074] Based on this, in the embodiment, through the above setting, it can be ensured that the end of the third section 123 away from the second section 122 does not exceed the bottom plate 13 after assembly, so that the welding joint formed by the connection between the pole 12 and the bottom plate 13 is located in the height difference between the pole 12 and the matching through hole 131, thereby improving the flatness of the side of the bottom plate 13 away from the end cover 11.

[0075] Please refer to Figure 7 In some embodiments, a sunken platform 132 is arranged on the side of the bottom plate 13 away from the end cover 11. The matching through hole 131 penetrates the bottom wall of the sunken platform 132. The depth dimension of the sunken platform 132 is H2, which satisfies 0.1mm≤H2≤0.6mm.

[0076] Exemplarily, H1=H0-H2.

[0077] It can be understood that the depth dimension H2 of the sunken platform 132 includes but is not limited to 0.12mm, 0.15mm, 0.2mm, 0.23mm, 0.27mm, 0.31mm, 0.33mm, 0.37mm, 0.39mm, 0.41mm, 0.44mm, 0.47mm, 0.49mm, 0.51mm, 0.53mm, 0.55mm, 0.57mm, 0.58mm, 0.59mm, 0.59mm, 0.6mm.

[0078] In the embodiment, through the above limitation, on the one hand, the sunken platform 132 can have sufficient depth to accommodate the welding joint, and on the other hand, the depth dimension of the sunken platform 132 can be prevented from being too large to affect the cooperation between the bottom plate 13 and the third section 123, so as to ensure that the bottom plate 13 and the third section 123 have appropriate cooperation area, thereby facilitating to ensure the reliability of the connection between the bottom plate 13 and the third section 123.

[0079] Please refer to Figure 7 In some embodiments, a sink 132 is arranged on the side of the bottom plate 13 away from the end cover 11. The matching through hole 131 penetrates the bottom wall of the sink 132. Among them, the diameter of the matching through hole 131 is d3, and the diameter of the sink 132 is d4, which satisfies: d3+0.8mm≤d4≤d3+3mm.

[0080] It can be understood that the diameter d4 of the sink 132 includes but is not limited to d3+0.85mm, d3+1.02mm, d3+1.17mm, d3+1.33mm, d3+1.48mm, d3+1.63mm, d3+1.79mm, d3+1.94mm, d3+2.09mm, d3+2.24mm, d3+2.39mm, d3+2.54mm, d3+2.69mm, d3+2.84mm, d3+2.99mm, d3+2.14mm, d3+2.29mm, d3+2.44mm, d3+2.59mm, d3+2.74mm, d3+2.89mm, d3+3mm.

[0081] In the present embodiment, through the above definition, on the one hand, the diameter of the sink 132 can be avoided to be too small to accommodate the welding mark, and on the other hand, the diameter of the sink 132 can be avoided to be too large to affect the area of the side of the bottom plate 13 away from the end cover 11 and the tab connection, so as to ensure the reliability of the tab and the bottom plate 13 connection.

[0082] Please refer to Figure 3 In some embodiments, the pole 12 further includes a terminal 125. The terminal 125 is located on the side of the end cover 11 away from the sealing ring 14. The terminal 125 is connected to the end of the first section 121 away from the second section 122. The outer diameter of the terminal 125 is greater than the outer diameter of the first section 121.

[0083] It can be understood that the terminal 125 combines the bottom plate 13 to clamp the pole 12 on the end cover 11, so that the pole 12 can be avoided to move relative to the end cover 11, thereby improving the stability of the pole 12 fixed to the end cover 11.

[0084] Please refer to Figure 8 , Figure 8 is Figure 2 an enlarged view of B in FIG. 8. In some embodiments, the material of the terminal 125 is not the same as the material of the first section 121.

[0085] It can be understood that the electrode assembly 22 includes a positive electrode sheet and a negative electrode sheet. The current collector of the positive electrode sheet is aluminum, and the current collector of the negative electrode sheet is copper. In order to reduce the cost and weight of the battery cell 2, the external circuit of the battery cell 2 uses aluminum material for current transmission. However, within the battery cell 2, in order to ensure the overcurrent stability, the current collector of the negative electrode sheet and the part connected with the pole 12 are of the same material, which is copper. Therefore, in order to improve the conductivity of the pole 12 and control the weight and cost of the battery cell 2, the negative pole 12 can use a copper-aluminum composite pole 12 to connect the current collector of the negative electrode sheet and the external circuit. The copper material of the copper-aluminum composite pole 12 is connected with the negative current collector, and the aluminum material of the copper-aluminum composite pole 12 is connected with the external circuit.

[0086] Based on this, in the present embodiment, the material of the terminal 125 is different from the material of the first section 121. Specifically, the material of the first section 121 is copper, and the material of the terminal 125 is aluminum. In this way, the conductivity of the negative pole 12 can be improved, and the weight and cost of the battery cell 2 can be controlled.

[0087] Please refer to Figure 8 In some embodiments, the first section 121 extends radially outward to form a support portion 126 at one end close to the terminal 125, and the support portion 126 is connected with the terminal 125. In this way, the bonding surface between the first section 121 and the terminal 125 can be increased, so that the overcurrent capacity between the first section 121 and the terminal 125 can be improved.

[0088] Please refer to Figure 9 , Figure 9 is a structural schematic diagram of the battery cell 2 provided by the embodiments of the present application. Accordingly, the embodiments of the present application provide a battery cell 2, which includes a shell 21, an electrode assembly 22, and a cover plate assembly 1 of some embodiments of the present application. The shell 21 has a receiving cavity 23. The electrode assembly 22 is arranged in the receiving cavity 23. The end cover 11 is covered with the shell 21. The electrode assembly 22 is connected with the bottom plate 13.

[0089] It can be understood that the cover plate assembly 1 is provided with two poles 12, one of which is a positive pole, and the other of which is a negative pole. The bottom plate 13 connected with the positive pole is a positive bottom plate 13, and the bottom plate 13 connected with the negative pole is a negative bottom plate.

[0090] It can be understood that the electrode assembly 22 includes a positive electrode sheet, a separator, and a negative electrode sheet arranged in sequence. The positive electrode sheet is connected with the positive bottom plate through a positive electrode tab, and the negative electrode sheet is connected with the negative bottom plate through a negative electrode tab.

[0091] In the embodiment, by adopting the cover plate assembly 1 provided by some embodiments of the present application, the sealing surface is formed between the sealing ring 14 and the bottom plate 13 and the end cover 11, and the sealing surface is also formed between the sealing ring 14 and the pole 12. Thus, when there is a leakage channel between the bottom plate 13 and the pole 12, the sealing surface between the sealing ring 14 and the pole 12 can block the leakage channel, so as to effectively prevent the internal medium of the battery cell 2 from leaking from the joint between the pole 12 and the end cover 11, thereby improving the sealing performance of the battery cell 2.

[0092] In addition, the battery cell 2 comprises the cover plate assembly 1 provided by some embodiments of the present application, and correspondingly, the battery cell 2 has all the beneficial effects of the cover plate assembly 1 provided by some embodiments of the present application, which will not be repeated here.

[0093] Correspondingly, some embodiments of the present application provide a battery pack 3. The battery pack 3 comprises the battery cell 2 described above. The battery cell 2 is multiple. The multiple battery cells 2 are electrically connected.

[0094] It can be understood that the battery pack 3 can further comprise a box body 31 and a box cover 32. The box body 31 and the box cover 32 are covered with each other to define a mounting cavity, and the battery cell 2 is arranged in the mounting cavity.

[0095] It can be understood that in the multiple battery cells 2, some battery cells 2 can be connected in series, some battery cells 2 can be connected in parallel, and some battery cells 2 can be connected in series and some battery cells 2 can be connected in parallel.

[0096] It can be understood that the battery pack 3 comprises the battery cell 2 provided by some embodiments of the present application, and correspondingly, the battery pack 3 has all the beneficial effects of the battery cell 2 provided by some embodiments of the present application, which will not be repeated here.

[0097] The above describes the embodiments of the present application in detail, and the principles and implementation manners of the present application are described by applying specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manner and application range can be changed, and the above description should not be understood as limiting the present application.

Claims

1. A cover plate assembly, characterized by The application relates to a cover plate assembly of a battery cell. The cover plate assembly comprises: an end cover; a pole column comprising a first section and a second section connected to each other, the second section having a smaller diameter than the first section, the first section having a first shoulder surface facing the second section, the first section being arranged on the end cover; a bottom plate arranged on an end of the second section away from the first section; and a sealing ring arranged on the second section and between the end cover and the bottom plate, the sealing ring having a first end surface facing away from the bottom plate.

2. The cover plate assembly of claim 1, wherein, The first end surface is in abutment with the first shoulder surface.

3. The cover plate assembly of claim 2, wherein, The sealing ring further has a second end surface facing the bottom plate, and a groove is arranged on the first end surface and / or the second end surface.

4. The cover plate assembly of claim 3, wherein, The groove extends in a circumferential direction of the sealing ring and has an annular shape.

5. The cover plate assembly of any one of claims 1-4, wherein, The width of the groove gradually decreases in a direction close to the bottom of the groove.

6. The cover plate assembly of any one of claims 1-4, wherein, The outer diameter of the first section is d1, and the inner diameter of the sealing ring is d2, and d1 is greater than or equal to d2+0.6mm.

7. The cover plate assembly of claim 6, wherein, The pole column further comprises a third section connected to an end of the second section away from the first section, and the third section has a smaller diameter than the second section, the second section having a second shoulder surface facing the third section, the bottom plate being arranged on the third section and in abutment with the second shoulder surface.

8. The cover plate assembly of claim 7, wherein, A matching through hole is arranged on the bottom plate, the third section is arranged in the matching through hole and connected to the bottom plate.

9. The cover plate assembly of claim 7, wherein, The depth of the matching through hole is H0, and the height of the third section is H1, and H0 is greater than or equal to H1+0.1mm.

10. The cover plate assembly of claim 9, wherein, A sunken platform is arranged on a side of the bottom plate away from the end cover, and the matching through hole penetrates a bottom wall of the sunken platform. The depth of the sunken platform is H2, and 0.1mm<=H2<=0.6mm.

11. The cover plate assembly of any one of claims 1-4, wherein, The diameter of the matching through hole is d3, and the diameter of the sunken platform is d4, and d3+0.8mm<=d4<=d3+3mm.

12. The cover plate assembly of claim 11, wherein, The pole column further comprises a terminal, the terminal being arranged on a side of the end cover away from the sealing ring, the terminal being connected to an end of the first section away from the second section, and the outer diameter of the terminal is greater than the outer diameter of the first section.

13. The cover plate assembly of claim 12, wherein, The material of the terminal is different from or the same as the material of the first section.

14. An electric cell, characterized by An end of the first section close to the terminal extends radially outward to form a support part, and the support part is connected to the terminal. The application relates to a battery cell. The battery cell comprises: a shell having a receiving cavity; 15. A battery pack, characterized by an electrode assembly arranged in the receiving cavity; and the cover plate assembly as claimed in any one of claims 1-13, the end cover being covered by the shell, and the electrode assembly being connected to the bottom plate. The battery cell comprises a plurality of the electrode assemblies, and the plurality of electrode assemblies are electrically connected.

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