Cover plate assembly and battery cell

Abstract

The invention relates to the technical field of batteries, and discloses a cover plate assembly and a battery cell. The cover plate assembly comprises: a cover plate provided with a pole hole; the riveting block is arranged on one side of the cover plate, a riveting hole corresponding to the pole hole is formed in the riveting block, the riveting hole comprises a first hole section and a second hole section, the first hole section is connected to the end, close to the cover plate, of the second hole section, the opening size of the first hole section is smaller than that of the second hole section, and the first hole section and the second hole section are arranged in the width direction. At least one side of the inner wall of the first hole section is provided with a concave part; and the pole comprises a pole body, the pole body comprises a first pole part and a second pole part, the first pole part is arranged in the pole hole in a penetrating manner, and the second pole part is arranged in the riveting hole in a penetrating manner. The concave part is arranged on the inner wall of the first hole section, so that the distance between the second column part and the riveting block in the width direction is increased, a material expansion space is reserved for material expansion of the second column part in the riveting process, the riveting block is prevented from deforming in the width direction, the width of the riveting block is prevented from being out of tolerance, and the consistency of the width of the riveted riveting block is guaranteed.

Description

Technical Field

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

[0002] The cover assembly consists of a cover body, a rivet block, an upper plastic, a pole, a lower plastic, a sealing ring and other structures. The pole is inserted into the through hole on the cover body and the through hole on the rivet block, and the pole is riveted to the cover body through the rivet block. After riveting, the pole expands in a direction perpendicular to the axis of the pole, and the column section on the pole that matches the rivet block squeezes the rivet block in a direction away from the axis of the pole. The width of the rivet block is usually small. After the pole and the rivet block are riveted, the rivet block is squeezed outward by the pole, which can easily cause the rivet block to expand and deform severely in the width direction. The edge of the rivet block is propped up outward by the pole and the upper plastic is stretched, resulting in an excessive width of the rivet block and poor width consistency of the rivet block, which in turn makes it difficult to clamp the battery cell assembly. Summary of the Invention

[0003] In view of this, the present invention provides a cover plate assembly and a battery cell to solve the problem of poor width consistency of riveted blocks after riveting.

[0004] In a first aspect, the present invention provides a cover plate assembly, comprising: a cover plate, provided with a pole hole; a rivet block, arranged on one side of the cover plate, the rivet block being provided with a rivet hole corresponding to the pole hole, the rivet hole comprising a first hole segment and a second hole segment, the first hole segment being connected to one end of the second hole segment close to the cover plate, and the opening size of the first hole segment being smaller than the opening size of the second hole segment, and a recessed portion being provided on at least one side of the inner wall of the first hole segment along the width direction; a pole, comprising a column, the column comprising a first column portion and a second column portion, the first column portion being passed through the pole hole, and the second column portion being passed through the rivet hole.

[0005] Beneficial effect: By arranging a recessed portion on the inner wall of the first hole section with a smaller opening size on the rivet hole of the rivet block, and the recessed portion is located on at least one side of the inner wall of the first hole section along the width direction, the recessed portion increases the distance between the second column portion and the rivet block along the width direction, thereby reserving space for the second column portion to expand during the riveting process, meeting the expansion demand of the second column portion, avoiding the second column portion from excessively squeezing the first hole section of the rivet hole and causing the rivet block to expand and deform along the width direction, thereby avoiding the rivet block width deviation, ensuring the consistency of the rivet block width after riveting, thereby avoiding difficulties in clamping the battery cell assembly, and improving the reliability of the cover assembly.

[0006] In an optional embodiment, recessed portions are respectively provided on both sides of the inner wall of the first hole segment along the width direction, and a recessed bottom wall is formed on the side of each recessed portion away from the rivet hole, and the vertical distance between the two recessed bottom walls is N; the opening size of the second hole segment along the width direction is d; the size of the second column portion along the width direction is A; wherein, the relationship between N, d and A satisfies the following equation: 0.2≤(NA) / (dA)≤0.6.

[0007] Beneficial effect: By limiting the value of (NA) / (dA) within the range of 0.2 to 0.6, it is ensured that the recessed portion on the first hole segment can provide a reasonable space for material expansion, which can not only ensure the consistency of the width of the rivet block after riveting and avoid the width of the rivet block from exceeding the tolerance, but also ensure that the second column portion and the inner wall of the rivet hole have sufficient contact area, ensure that there is a small resistance between the pole and the rivet block, and ensure that the rivet block can withstand sufficient tension.

[0008] In an optional embodiment, the opening contour line of the second hole segment is runway-shaped; the opening contour line of the first hole segment includes semicircular segments arranged opposite to each other along the length direction, and straight line segments arranged opposite to each other along the width direction, the diameter of the semicircular segment is n, and the vertical distance between the two straight line segments is N, where N>n, to form the recessed portion.

[0009] Beneficial effect: By setting the opening contour line of the second hole segment to be runway-shaped, and the first hole segment is a structure improved on the basis of the runway-shaped through-hole, it is convenient to process the recessed portions on both sides of the first hole segment along the width direction, and the opening area of ​​the runway-shaped through-hole is large, and the corresponding cross-sectional area of ​​the second column portion of the pole is large, which can effectively increase the flow area of ​​the pole, and the recessed portions are formed on both sides of the runway-shaped structure along the width direction, which meets the material expansion requirements of the runway-shaped pole structure, thereby effectively avoiding the extrusion deformation problem of the riveting block along the width direction, and has high reliability.

[0010] In an optional embodiment, the two recessed portions are symmetrically arranged, and the recessed depth of each recessed portion along the width direction is t, where t=(Nn) / 2.

[0011] Beneficial effect: By setting the depth of the two recessed portions along the width direction to be half of the difference between the vertical distance N between the two recessed bottom walls and the diameter n of the semicircular segment, the two recessed portions are symmetrically arranged on both sides of the first hole segment along the width direction, thereby ensuring the uniformity of the expansion space reserved on both sides of the first hole segment along the width direction, avoiding the convex deformation of the other side of the rivet block due to insufficient expansion space on one side during the expansion process along the width direction when the pole is riveted, and further ensuring the consistency of the width of the rivet block after riveting.

[0012] In an optional embodiment, the diameter n of the semicircular segment and the dimension A of the second column portion along the width direction satisfy the relationship: 0.08 mm ≤ nA ≤ 0.15 mm.

[0013] Beneficial effect: It can ensure smooth assembly of the pole and the riveted block, and avoid excessive positioning deviation between the pole and the riveted block, thereby ensuring assembly accuracy and battery cell performance.

[0014] In an optional embodiment, the opening dimension d of the second hole segment along the width direction and the dimension A of the second column portion along the width direction satisfy the relationship: 0.8 mm ≤ dA ≤ 2 mm.

[0015] Beneficial effects: It can ensure that the pole has sufficient riveted expansion area after riveting, thereby ensuring that the riveted block can withstand sufficient tension and ensure the safety of the battery cell, and can avoid the phenomenon of insufficient pole expansion, thereby ensuring smooth welding between the pole and the riveted block, ensuring welding quality, and ensuring good electrical conductivity between the pole and the riveted block.

[0016] In an optional embodiment, a value range of a dimension A of the second column portion along the width direction is: 4 mm ≤ A ≤ 20 mm.

[0017] Beneficial effect: limiting the width dimension of the second column portion to a reasonable range can ensure that the pole can be smoothly processed and formed and riveted, and can also ensure that the plate body effectively squeezes the sealing ring, thereby ensuring the sealing of the cover assembly.

[0018] In an optional embodiment, the semicircular segment and the straight line segment are connected by an oblique line segment, and the angle between the oblique line segment and the straight line segment is an obtuse angle.

[0019] Beneficial effect: By setting the semicircular segment and the straight segment to be connected by an oblique line segment, the processing and forming of the recessed portion is facilitated, and by setting the angle between the oblique line segment and the straight line segment to be an obtuse angle, the sharpness of the corner between the semicircular segment and the straight line segment can be reduced, thereby reducing the stress concentration phenomenon at the corner, thereby improving the reliability of the riveted block.

[0020] In an optional embodiment, the rivet hole further includes a third hole segment, the third hole segment is connected to an end of the second hole segment away from the first hole segment, and an opening size of the third hole segment is larger than an opening size of the second hole segment.

[0021] Beneficial effect: By setting a third hole segment on the upper side of the second hole segment, and the third hole segment has a larger opening area, it can be ensured that the weld does not exceed the upper surface of the rivet block, thereby ensuring the neatness of the appearance of the cover assembly and facilitating the subsequent connection between different battery cells.

[0022] In a second aspect, the present invention further provides a battery cell comprising: a housing having an open end; an electrode group disposed within the housing; and the aforementioned cover plate assembly, the cover plate assembly being disposed over the open end of the housing. Because the battery cell includes the cover plate assembly, it has the same effects as the cover plate assembly and is not further described here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A top view of a cover plate assembly before riveting according to an embodiment of the present invention;

[0025] Figure 2 for Figure 1 Cross-sectional view in the middle BB direction;

[0026] Figure 3 for Figure 1 Cross-sectional view in CC direction;

[0027] Figure 4 A top view of a riveting block according to an embodiment of the present invention;

[0028] Figure 5 for Figure 4 A partial enlarged schematic diagram of the area where the rivet holes of the rivet block are located is shown;

[0029] Figure 6 for Figure 4 Cross-sectional view in the EE direction;

[0030] Figure 7 This is a schematic structural diagram of a pole before riveting according to an embodiment of the present invention;

[0031] Figure 8 for Figure 7 The front view of the pole shown;

[0032] Figure 9 for Figure 7 A top view of the pole shown;

[0033] Figure 10 This is a top view of a riveted cover plate assembly before improvement;

[0034] Figure 11 for Figure 10 Cross-sectional view in the FF direction;

[0035] Figure 12 for Figure 10 An exploded view of the cover assembly is shown;

[0036] Figure 13 A top view of a riveting block before improvement;

[0037] Figure 14 for Figure 13 Cross-sectional view in the HH direction.

[0038] Description of reference numerals:

[0039] 1. Cover plate; 101. Pole hole; 102. Explosion-proof valve hole; 2. Riveted block; 201. Recessed portion; 2011. Recessed bottom wall; 210. Riveted hole; 211. First hole section; 2111. Semicircular section; 2112. Straight line section; 2113. Oblique line section; 2114. First line segment; 212. Second hole section; 213. Third hole section; 3. Pole; 310. Column; 311. First column portion; 312. Second column portion; 320. Plate; 4. Sealing ring; 5. First plastic part; 501. First through hole; 6. Second plastic part; 601. Second through hole; 7. Explosion-proof valve; 8. Explosion-proof patch. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0041] The cover plate assembly is a key component in the battery. Its function is to weld with the shell to form a sealed cavity, lead out the positive and negative electrodes of the electrode group, and serve as an assembly carrier. The traditional riveted cover plate consists of the cover plate body, riveted block, upper plastic, pole, lower plastic, sealing ring and other structures. In combination with the trend of lightweight structural parts and simplified structure, the cover plate of the blade battery cell is currently simplified from a double cylindrical pole to a runway-type single pole structure (such as Figure 10 (As shown). The cover plate and rivet block in currently common blade cells are both relatively small in width. The section of the pole structure that mates with the rivet block is the rivet expansion section. After riveting, the rivet expansion section expands, pushing the rivet block apart. The rivet block then pushes the plastic over it, causing the rivet block to become too wide, which in turn makes it difficult to clamp the battery cell together. Therefore, it is crucial to address the issue of the rivet block expanding and deforming along its width due to the compression of the pole after riveting, resulting in excessive rivet block width.

[0042] The following combination Figures 1 to 14 , describing embodiments of the present invention.

[0043] According to an embodiment of the present invention, on the one hand, a cover plate assembly is provided, such as Figures 1 to 9 As shown, the cover plate assembly includes: a cover plate 1, a rivet block 2 and a pole 3. The cover plate 1 is provided with a pole hole 101; the rivet block 2 is arranged on one side of the cover plate 1, and a rivet hole 210 corresponding to the pole hole 101 is provided on the rivet block 2, and the rivet hole 210 includes a first hole section 211 and a second hole section 212, the first hole section 211 is connected to the end of the second hole section 212 close to the cover plate 1, and the opening size of the first hole section 211 is smaller than the opening size of the second hole section 212, and along the width direction, at least one side of the inner wall of the first hole section 211 is provided with a recessed portion 201; the pole 3 includes a column 310, and the column 310 includes a first column portion 311 and a second column portion 312, the first column portion 311 is passed through the pole hole 101, and the second column portion 312 is passed through the rivet hole 210. Wherein, the width direction refers to Figures 4 and 5 The arrow in the middle points to the "width direction".

[0044] It should be noted that the pole hole 101 and the rivet hole 210 are both through holes, and the column 310 passes through the pole hole 101 and the rivet hole 210 in sequence. The first hole section 211 in the rivet hole 210 is a positioning section, and the second hole section 212 is a main material expansion section. The opening size of the first hole section 211 is smaller than the opening size of the second hole section 212, which means that the size of the first hole section 211 in the length direction and the width direction are smaller than the size of the second hole section 212; there is a gap between the second column portion 312 and the inner wall of the rivet hole 210 before riveting, and after riveting, the second column portion 312 moves away from the pole. The material expands in the direction of the center line of the body 310 to fill the gap. At the same time, since the opening size of the second hole section 212 is larger than the opening size of the first hole section 211, the downward movement of the column 310 relative to the riveted block 2 can be limited. Further, the pole 3 also includes a plate 320. The plate 320 is located on the side of the cover 1 away from the riveted block 2, and the outline of the positive projection of the plate 320 on the cover 1 is larger than the opening outline of the pole hole 101. The plate 320 can limit the upward movement of the pole 3 relative to the cover 1, thereby achieving relative fixation between the pole 3, the riveted block 2 and the cover 1. Among them, the length direction refers to Figures 4 and 5 The middle arrow points to the "length direction"; upward refers to the direction Figures 2 to 3 The arrow in the middle points to the direction of "up", and downwards means towards Figures 2 to 3 The arrow in the middle points to the direction of "down".

[0045] The cover plate assembly of the present embodiment is applied, by providing a recessed portion 201 on the inner wall of the first hole section 211 with a smaller opening size on the rivet hole 210 of the rivet block 2, and the recessed portion 201 is located on at least one side of the inner wall of the first hole section 211 along the width direction, the recessed portion 201 increases the distance between the second column portion 312 and the rivet block 2 along the width direction, thereby reserving space for the second column portion 312 to expand during the riveting process, meeting the expansion demand of the second column portion 312, avoiding the second column portion 312 from excessively squeezing the first hole section 211 of the rivet hole 210, causing the rivet block 2 to expand and deform along the width direction, thereby avoiding the width of the rivet block 2 from exceeding the tolerance, ensuring the consistency of the width of the rivet block 2 after riveting, thereby avoiding the difficulty of clamping the battery cell assembly, and improving the reliability of the cover plate assembly.

[0046] In one embodiment, further combined Figures 5 and 6 As shown, along the width direction, recessed portions 201 are respectively provided on both sides of the inner wall of the first hole section 211, and a recessed bottom wall 2011 is formed on the side of each recessed portion 201 away from the rivet hole 210, and the vertical distance between the two recessed bottom walls 2011 is N; the opening dimension of the second hole section 212 along the width direction is d; the dimension of the second column portion 312 along the width direction is A; wherein, N, d and A satisfy the relationship: 0.2≤(NA) / (dA)≤0.6, and the units of N, d and A are all mm.

[0047] It should be noted that the recessed portion 201 forms an escape space, and the recessed bottom wall 2011 is a plane parallel to the centerline of the rivet hole 210 and parallel to the length direction. The vertical distance N between the two recessed bottom walls 2011 is the maximum opening dimension of the first hole segment 211 along the width direction. The cross-section of the column 310 is runway-shaped or circular. When the cross-section of the column 310 is runway-shaped, the cross-section of the rivet hole 210 is also runway-shaped. A is the vertical distance between the two straight segments in the runway-shaped outline of the second column portion 312, and d is the vertical distance between the two straight segments in the runway-shaped outline of the second hole segment 212. Alternatively, when the cross-section of the column 310 is circular, the cross-section of the rivet hole 210 is also circular, A is the diameter of the circle formed by the second column portion 312, and d is the diameter of the circle formed by the second hole segment 212.

[0048] It should be noted that NA is the total size of the material expansion space corresponding to the first hole segment 211 along the width direction; the opening size of the second hole segment 212 is larger than the opening size of the first hole segment 211, and the column segment on the second column portion 312 corresponding to the second hole segment 212 is the main material expansion segment, and dA is the total size of the material expansion space corresponding to the second hole segment 212 along the width direction. If (NA) / (dA) is less than 0.2, the expansion space corresponding to the first hole segment 211 is insufficient, resulting in the second column portion 312 excessively squeezing the first hole segment 211 and the second hole segment 212, causing the width of the rivet block 2 to be out of tolerance, and the width consistency of the rivet block 2 after riveting is poor; if (NA) / (dA) is greater than 0.6, the expansion space corresponding to the first hole segment 211 is too large, resulting in insufficient contact area between the second column portion 312 and the inner wall of the rivet hole 210, and the resistance between the pole 3 and the rivet block 2 is out of tolerance, and the expansion force surface between the pole 3 and the rivet block 2 is insufficient, and the rivet block 2 can withstand insufficient tensile force.

[0049] Therefore, by limiting the value of (NA) / (dA) to the range of 0.2 to 0.6, it is ensured that the recessed portion 201 on the first hole segment 211 can provide a reasonable space for material expansion, which can not only ensure the consistency of the width of the riveted block 2 after riveting and avoid the width of the riveted block 2 from exceeding the tolerance, but also ensure that the second column portion 312 has a sufficient contact area with the inner wall of the riveted hole 210, ensure that there is a small resistance between the pole 3 and the riveted block 2, and ensure that the riveted block 2 can withstand sufficient tension.

[0050] The following examples illustrate the effect of different values ​​of (NA) / (dA) on the size of the pole after riveting. The measurement results of the embodiment and the comparative example are shown in Tables 1 to 3. Among them, the cover plate assembly of the embodiment satisfies the relationship of 0.2≤(NA) / (dA)≤0.6; the cover plate assembly of the comparative example does not satisfy the relationship of 0.2≤(NA) / (dA)≤0.6.

[0051] The dimension A of the second column portion 312 of the cover plate assembly in Table 1 along the width direction is 4 mm, the opening dimension d of the second hole section 212 of the rivet block 2 along the width direction is 5 mm, the design value of the width of the rivet block 2 is 10.5 mm, and different values ​​of the vertical distance N between the two recessed bottom walls 2011 are taken to obtain different values ​​of (NA) / (dA) to verify whether the requirements of the width W of the rivet block 2 being 10.5±0.05 mm and the resistance R between the rivet block 2 and the pole 3 being ≤0.035 mΩ are met.

[0052] Table 1

[0053] A(mm) N(mm) d(mm) (NA) / (dA) W(mm) R(mΩ) Example 1-1 4 4.2 5 0.2 10.5 0.0184 Example 1-2 4 4.25 5 0.25 10.543 0.0213 Examples 1-3 4 4.33 5 0.33 10.532 0.0235 Examples 1-4 4 4.4 5 0.4 10.52 0.0265 Examples 1-5 4 4.51 5 0.51 10.509 0.0287 Examples 1-6 4 4.6 5 0.6 10.512 0.035 Comparative Example 1-1 4 4.11 5 0.11 10.569 0.0154 Comparative Example 1-2 4 4.16 5 0.16 10.561 0.0145 Comparative Examples 1-3 4 4.64 5 0.64 10.492 0.041 Comparative Examples 1-4 4 4.71 5 0.71 10.505 0.048

[0054] The dimension A of the second column portion 312 of the cover plate assembly in Table 2 along the width direction is 5 mm, the opening dimension d of the second hole section 212 of the rivet block 2 along the width direction is 6.2 mm, the design value of the width of the rivet block 2 is 12.5 mm, and different values ​​of the vertical distance N between the two recessed bottom walls 2011 are taken to obtain different values ​​of (NA) / (dA) to verify whether the requirements of the width W of the rivet block 2 being 12.5±0.05 mm and the resistance R between the rivet block 2 and the pole 3 being ≤0.035 mΩ are met.

[0055] Table 2

[0056] A(mm) N(mm) d(mm) (NA) / (dA) W(mm) R(mΩ) Example 2-1 5 5.24 6.2 0.200 12.5 0.0181 Example 2-2 5 5.35 6.2 0.292 12.545 0.0203 Example 2-3 5 5.45 6.2 0.375 12.534 0.0245 Examples 2-4 5 5.57 6.2 0.475 12.521 0.0261 Examples 2-5 5 5.65 6.2 0.542 12.505 0.0277 Examples 2-6 5 5.72 6.2 0.600 12.508 0.035 Comparative Example 2-1 5 5.15 6.2 0.125 12.565 0.0144 Comparative Example 2-2 5 5.2 6.2 0.167 12.558 0.0149 Comparative Examples 2-3 5 5.8 6.2 0.667 12.494 0.041 Comparative Examples 2-4 5 5.9 6.2 0.750 12.506 0.0452

[0057] The dimension A of the second column portion 312 of the cover plate assembly in Table 3 along the width direction is 5.5 mm, the opening dimension d of the second hole section 212 of the rivet block 2 along the width direction is 6.7 mm, the design value of the width of the rivet block 2 is 13 mm, and different values ​​of the vertical distance N between the two recessed bottom walls 2011 are taken to obtain different values ​​of (NA) / (dA) to verify whether the requirements of the width of the rivet block 2 W=13±0.05 mm and the resistance R≤0.035 mΩ between the rivet block 2 and the pole 3 are met.

[0058] Table 3

[0059] A(mm) N(mm) d(mm) (NA) / (dA) W(mm) R(mΩ) Example 3-1 5.5 5.74 6.7 0.20 13.05 0.0202 Example 3-2 5.5 5.79 6.7 0.24 13.042 0.0233 Example 3-3 5.5 5.879 6.7 0.32 13.036 0.0238 Examples 3-4 5.5 5.99 6.7 0.41 13.026 0.0261 Examples 3-5 5.5 6.09 6.7 0.49 13.021 0.0277 Examples 3-6 5.5 6.22 6.7 0.60 13.015 0.035 Comparative Example 3-1 5.5 5.69 6.7 0.16 13.062 0.0134 Comparative Example 3-2 5.5 5.721 6.7 0.18 13.053 0.0156 Comparative Example 3-3 5.5 6.31 6.7 0.68 13.005 0.038 Comparative Examples 3-4 5.5 6.37 6.7 0.73 13.013 0.058

[0060] As can be seen from Table 1, in Examples 1-1 to 1-6, (NA) / (dA) is within the range of 0.2 to 0.6 as defined in this application, the width W of the riveted block after riveting is within the range of 10.5±0.05 mm, and the resistance R is less than or equal to 0.035 mΩ, that is, the width of the riveted block after riveting and the resistance between the riveted block and the pole structure meet the requirements, the riveted block after riveting does not have a width deviation, the width consistency of the riveted block is good, and the resistance between the riveted block and the pole structure is small, which meets the requirements; while in Comparative Examples 1-1 to 1-2, (NA) / ( dA) is less than 0.2, which is not within the range defined in the present application. Although the resistance R is less than 0.035 mΩ, the width W of the riveted block after riveting is greater than 10.55 mm (i.e., 10.5 + 0.05 mm), the width of the riveted block is out of tolerance, and the width consistency is poor. In Comparative Examples 1-3 to 1-4, (NA) / (dA) is greater than 0.6, which is not within the range defined in the present application. Although the width W of the riveted block after riveting is within the range of 10.5 ± 0.05 mm, the resistance R is greater than 0.035 mΩ, and the resistance between the riveted block and the pole structure is too large, which does not meet the requirements.

[0061] As can be seen from Table 2, in Examples 2-1 to 2-6, (NA) / (dA) is within the range of 0.2 to 0.6 as defined in this application, the width W of the riveted block after riveting is within the range of 12.5±0.05mm, and the resistance R is less than or equal to 0.035mΩ, that is, the width of the riveted block after riveting and the resistance between the riveted block and the pole structure meet the requirements, the riveted block after riveting does not have a width deviation, the width consistency of the riveted block is good, and the resistance between the riveted block and the pole structure is small, which meets the requirements; while in Comparative Examples 2-1 to 2-2, (NA) / ( dA) is less than 0.2, which is not within the range defined in the present application. Although the resistance R is less than 0.035 mΩ, the width W of the riveted block after riveting is greater than 12.55 mm (i.e., 12.5 + 0.05 mm), the width of the riveted block is out of tolerance, and the width consistency is poor. In Comparative Examples 2-3 to 2-4, (NA) / (dA) is greater than 0.6, which is not within the range defined in the present application. Although the width W of the riveted block after riveting is within the range of 12.5 ± 0.05 mm, the resistance R is greater than 0.035 mΩ, and the resistance between the riveted block and the pole structure is too large, which does not meet the requirements.

[0062] As can be seen from Table 3, in Examples 3-1 to 3-6, (NA) / (dA) is within the range of 0.2 to 0.6 as defined in this application, the width W of the riveted block after riveting is within the range of 13±0.05 mm, and the resistance R is less than or equal to 0.035 mΩ, that is, the width of the riveted block after riveting and the resistance between the riveted block and the pole structure meet the requirements, the riveted block after riveting does not have a width deviation, the width consistency of the riveted block is good, and the resistance between the riveted block and the pole structure is small, which meets the requirements; while in Comparative Examples 3-1 to 3-2, (NA) / (dA) is less than 0.2, which is not within the range defined in this application. Although the resistance R is less than 0.035 mΩ, the width W of the riveted block after riveting is greater than 13.05 mm (i.e., 13 + 0.05 mm), the width of the riveted block is out of tolerance, and the width consistency is poor. In Comparative Examples 3-3 to 3-4, (NA) / (dA) is greater than 0.6, which is not within the range defined in this application. Although the width W of the riveted block after riveting is within the range of 13 ± 0.05 mm, the resistance R is greater than 0.035 mΩ, and the resistance between the riveted block and the pole structure is too large, which does not meet the requirements.

[0063] In summary, when the ratio of (NA) / (dA) is in the range of 0.2 to 0.6, that is, the ratio of the total size of the expansion space corresponding to the first hole segment 211 along the width direction to the total size of the expansion space corresponding to the second hole segment 212 along the width direction is in the range of 0.2 to 0.6, the width of the riveted block after riveting and the resistance performance between the riveted block and the pole can meet the requirements of battery cell use.

[0064] In one embodiment, the opening contour line of the second hole segment 212 is runway-shaped; the opening contour line of the first hole segment 211 includes semicircular segments 2111 arranged oppositely along the length direction, and straight segments 2112 arranged oppositely along the width direction, the diameter of the semicircular segment 2111 is n, and the vertical distance between the two straight segments 2112 is N, wherein N>n, so as to form the recessed portion 201. It should be noted that the units of N and n are both mm. The cross section of the column 310 of this embodiment is runway-shaped. The rivet hole 210 is an improvement on the traditional runway-shaped through hole. The cover plate assembly before the improvement is as follows. Figures 10 to 12 As shown, the riveting block 2 before improvement is as shown in FIG. Figures 13 and 14 As shown, the cross-section of the first hole segment 211 of the rivet hole 210 thereon is also runway-shaped. The outline of the runway-shaped through hole includes two semicircular segments 2111 arranged opposite to each other and a first line segment 2114 connecting the two semicircular segments 2111. The distance between the two first line segments 2114 is equal to the diameter n of the semicircular segment 2111. The recessed portion 201 of this embodiment is formed by recessing the area corresponding to the first line segment 2114 on the runway-shaped through hole before the improvement. The orthographic projection of the recessed bottom wall 2011 of the recessed portion 201 on the surface of the rivet block 2 is a straight line segment 2112.

[0065] Therefore, by setting the opening contour line of the second hole segment 212 to be runway-shaped, and the first hole segment 211 being a structure improved on the basis of the runway-shaped through hole, it is convenient to obtain the recessed portion 201 on both sides of the first hole segment 211 along the width direction, and the opening area of ​​the runway-shaped through hole is large, and the corresponding cross-sectional area of ​​the second column portion 312 of the pole is large, which can effectively increase the flow area of ​​the pole 3, and the recessed portions 201 are formed on both sides of the runway-shaped structure along the width direction, which meets the material expansion requirements of the runway-shaped pole structure, thereby effectively avoiding the extrusion deformation problem of the rivet block 2 along the width direction, and has higher reliability.

[0066] It should be noted that the inner wall of the runway-shaped through hole before the improvement includes two semicircular arc surfaces arranged oppositely along the length direction, and two rectangular surfaces arranged oppositely along the width direction. The recessed portion 201 of this embodiment is formed by recessing the entire rectangular surface. The size of the recessed portion 201 along the length direction is equal to the distance between the centers of the two semicircular segments 2111. In addition, along the direction of the center line of the rivet hole 210, the size of the recessed portion 201 is equal to the size of the first hole segment 211. Figures 2 to 3 The “up and down” direction indicated by the middle arrow is also the thickness direction of the rivet block 2 .

[0067] It should be noted that the column 310 of the pole 3 of this embodiment is runway-shaped, and the cross-section of the second column portion 312 is runway-shaped. The dimension A of the second column portion 312 along the width direction is equal to the short axis of the runway-shaped contour line, that is, equal to the diameter of the arc segments on both sides.

[0068] In one embodiment, the two recessed portions 201 are symmetrically arranged, and the recessed depth of each recessed portion 201 along the width direction is t, t=(Nn) / 2. It should be noted that Nn is the total avoidance space formed by the two recessed portions 201 on the first hole segment 211 along the width direction. By setting the recessed depth of the two recessed portions 201 along the width direction to be half of the difference between the vertical distance N between the two recessed bottom walls 2011 and the diameter n of the semicircular segment 2111, the two recessed portions 201 are symmetrically arranged on both sides of the first hole segment 211 along the width direction, thereby ensuring the uniformity of the expansion space reserved on both sides of the first hole segment 211 along the width direction, avoiding the convex deformation of the other side of the rivet block 2 due to insufficient expansion space on one side during the expansion process in the width direction when the pole 3 is riveted, and further ensuring the consistency of the width of the rivet block 2 after riveting.

[0069] In one embodiment, the diameter n of the semicircular segment 2111 and the dimension A of the second column portion 312 along the width direction satisfy the relationship: 0.08mm≤nA≤0.15mm. It should be noted that nA is the assembly clearance between the first hole segment 211 and the second column portion 312. If nA is less than 0.08mm, the assembly clearance is too small, and the assembly of the pole 3 and the riveted block 2 is difficult; if nA is greater than 0.15mm, the assembly clearance is too large, and the positioning deviation between the pole 3 and the riveted block 2 is too large, resulting in an excessive position deviation of the riveted block 2 and low assembly accuracy of the cover assembly. Therefore, by limiting nA to a value within the range of 0.08mm to 0.15mm, it is possible to ensure smooth assembly of the pole 3 and the riveted block 2, while avoiding excessive positioning deviation between the pole 3 and the riveted block 2, thereby ensuring assembly accuracy and battery cell performance.

[0070] In one embodiment, the opening dimension d of the second hole segment 212 along the width direction and the dimension A of the second column portion 312 along the width direction satisfy the relationship: 0.8mm≤dA≤2mm. It should be noted that the spacing between the second hole segment 212 and the second column portion 312 is the main expansion space of the pole 3, and dA is the total size of the expansion space corresponding to the second hole segment 212 along the width direction. If dA is less than 0.8mm, the riveted expansion area of ​​the pole 3 after riveting is small, and the riveted block 2 can withstand less tension, affecting the safety of the battery cell; if dA is greater than 2mm, the main expansion space of the pole 3 provided by the riveted block 2 is too large, and it is very easy for the pole to be insufficiently expanded. There is a large gap between the pole 3 and the riveted block 2 after riveting, which makes it difficult to weld the joint between the pole 3 and the riveted block 2, and the conductivity between the pole 3 and the riveted block 2 is reduced.

[0071] Therefore, by limiting the value of dA to the range of 0.8mm to 2mm, it can be ensured that the pole 3 after riveting has sufficient riveting expansion area, thereby ensuring that the riveted block 2 can withstand sufficient tension and ensure the safety of the battery cell, and it can also avoid the phenomenon of insufficient pole expansion, thereby ensuring smooth welding between the pole 3 and the riveted block 2, ensuring welding quality, and ensuring good conductivity between the pole 3 and the riveted block 2.

[0072] In one embodiment, the dimension A of the second column portion 312 along the width direction has a value range of: 4mm≤A≤20mm. If A is less than 4mm, the dimension of the second column portion 312 along the width direction is too small, making it difficult to rivet the pole, and increasing the difficulty of production and processing; if A is greater than 20mm, the dimension of the second column portion 312 along the width direction is too large, which not only makes it difficult to rivet the pole, increasing the difficulty of production and processing, but also causes the dimension of the plate 320 extending in the width direction beyond the range where the column 310 is located to be insufficient. Since this portion is used to compress the sealing ring 4, the plate 320 will not have enough extrusion area on the sealing ring 4, affecting the sealing performance. Therefore, by limiting A to a value within the range of 4mm to 20mm and limiting the dimension of the second column portion 312 along the width direction to a reasonable range, it can be ensured that the pole 3 can be smoothly processed and riveted, and it can also ensure that the plate 320 effectively squeezes the sealing ring 4, thereby ensuring the sealing performance of the cover assembly.

[0073] In one embodiment, further combined Figure 5As shown, the semicircular segment 2111 and the straight segment 2112 are connected by an oblique line segment 2113, and the angle between the oblique line segment 2113 and the straight segment 2112 is an obtuse angle. By providing the oblique line segment 2113 to connect the semicircular segment 2111 and the straight segment 2112, the processing and forming of the recessed portion 201 is facilitated. By providing the obtuse angle between the oblique line segment 2113 and the straight segment 2112, the sharpness of the corner between the semicircular segment 2111 and the straight segment 2112 can be reduced, thereby reducing the stress concentration phenomenon at the corner, thereby improving the reliability of the riveting block 2.

[0074] In one embodiment, the rivet hole 210 further includes a third hole segment 213, which is connected to the end of the second hole segment 212 away from the first hole segment 211. The opening size of the third hole segment 213 is larger than the opening size of the second hole segment 212. It should be noted that along the center line of the rivet hole 210, the size of the second column portion 312 is equal to the sum of the sizes of the first hole segment 211 and the second hole segment 212. The upper surface of the second column portion 312 is flush with the upper end surface of the second hole segment 212. After the pole is riveted, the pole 3 and the rivet block 2 need to be welded. The welding position P is as shown in FIG. Figure 11 At the position indicated by the middle arrow, since the weld has a certain height, by setting the third hole section 213 on the upper side of the second hole section 212, and the third hole section 213 has a larger opening area, it can be ensured that the weld does not exceed the upper surface of the riveted block 2, thereby ensuring the neatness of the appearance of the cover assembly and facilitating the subsequent connection between different battery cells. Figure 3 and Figure 11 The arrow in the middle points to the direction of "up and down".

[0075] In one embodiment, the cover plate assembly further includes: a first plastic part 5 and a second plastic part 6, the first plastic part 5 is arranged between the rivet block 2 and the cover plate 1 to ensure insulation between the rivet block 2 and the cover plate 1, a first through hole 501 corresponding to the pole hole 101 is opened on the first plastic part 5, and the first through hole 501 is for the portion of the first column portion 311 close to the second column portion 312 to pass through; the second plastic part 6 is arranged on the side of the cover plate 1 away from the first plastic part 5, and a second through hole 601 is opened on the second plastic part 6, a partial section of the first column portion 311 close to the plate body 320 is passed through the second through hole 601, the plate body 320 is located on the side of the second plastic part 6 away from the cover plate 1, and the plate body 320 presses the second plastic part 6 toward the cover plate 1, and the second plastic part 6 is used to ensure insulation between the cover plate 1 and the pole group.

[0076] In one embodiment, the first plastic part 5 is an upper plastic and the second plastic part 6 is a lower plastic.

[0077] In one embodiment, the cover plate assembly further includes: a sealing ring 4 , which is disposed between the first column portion 311 and the pole hole 101 to ensure sealing and insulation between the pole 3 and the cover plate 1 .

[0078] In one embodiment, the cover plate assembly further includes an explosion-proof valve 7, and an explosion-proof valve hole 102 is further opened on the cover plate 1. The explosion-proof valve 7 is arranged in the explosion-proof valve hole 102. The explosion-proof valve 7 is suitable for opening when the air pressure inside the battery cell reaches a preset value, so as to timely discharge the high-temperature flue gas in the battery cell to prevent the battery cell from exploding; an explosion-proof patch 8 is affixed to the explosion-proof valve 7 to protect the explosion-proof valve.

[0079] The cover plate assembly of this embodiment optimizes the structure of the riveted block 2 by adding a recessed portion 201 on the inner side of the riveted hole 210 of the riveted block 2 to form an escape space, thereby providing space for the material to expand during the riveting process of the pole 3. This improves the deformation and dimensional deviation problems of the riveted block 2 caused by being squeezed by the second column portion 312 of the pole 3 after riveting, thereby improving the appearance yield of the cover plate assembly.

[0080] According to another aspect of an embodiment of the present invention, a battery cell is provided, comprising: a housing, an electrode group, and the aforementioned cover plate assembly. The housing has an open end; the electrode group is disposed within the housing; and the cover plate assembly covers the open end of the housing. Preferably, the battery cell is a lithium-ion battery cell for use in electric vehicles, energy storage, and other fields.

[0081] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A cover plate assembly, characterized in that: include: A cover plate having a pole hole; a rivet block disposed on one side of the cover plate, the rivet block being provided with a rivet hole corresponding to the pole hole, the rivet hole comprising a first hole segment and a second hole segment, the first hole segment being connected to an end of the second hole segment close to the cover plate, the opening size of the first hole segment being smaller than the opening size of the second hole segment, and a recess being provided on at least one side of an inner wall of the first hole segment along the width direction; The pole comprises a column body, wherein the column body comprises a first column portion and a second column portion, wherein the first column portion is inserted into the pole hole, and the second column portion is inserted into the rivet hole.

2. The cover plate assembly according to claim 1, wherein: Along the width direction, recessed portions are provided on both sides of the inner wall of the first hole segment, and a recessed bottom wall is formed on the side of each recessed portion away from the rivet hole. The vertical distance between the two recessed bottom walls is N; the opening dimension of the second hole segment along the width direction is d; and the dimension of the second column along the width direction is A; Among them, N, d and A satisfy the relationship: 0.2≤(NA) / (dA)≤0.

6.

3. The cover plate assembly according to claim 2, wherein: The opening contour line of the second hole segment is runway-shaped; the opening contour line of the first hole segment includes semicircular segments arranged oppositely along the length direction, and straight line segments arranged oppositely along the width direction, the diameter of the semicircular segment is n, and the vertical distance between the two straight line segments is N, where N>n, to form the recessed portion.

4. The cover plate assembly according to claim 3, wherein: The two recessed portions are symmetrically arranged, and the recessed depth of each recessed portion along the width direction is t, where t=(Nn) / 2.

5. The cover plate assembly according to claim 3, wherein: The diameter n of the semicircular segment and the dimension A of the second column portion along the width direction satisfy the relationship: 0.08 mm ≤ nA ≤ 0.15 mm.

6. The cover plate assembly according to claim 2, wherein: The opening dimension d of the second hole segment along the width direction and the dimension A of the second column portion along the width direction satisfy the relationship: 0.8 mm ≤ dA ≤ 2 mm.

7. The cover plate assembly according to claim 2, wherein: The value range of the dimension A of the second column portion along the width direction is: 4mm≤A≤20mm.

8. The cover plate assembly according to claim 3, wherein: The semicircular segment and the straight line segment are connected by an oblique line segment, and the angle between the oblique line segment and the straight line segment is an obtuse angle.

9. The cover plate assembly according to any one of claims 1 to 8, characterized in that: The rivet hole further includes a third hole segment connected to an end of the second hole segment away from the first hole segment, and an opening size of the third hole segment is larger than an opening size of the second hole segment.

10. A battery cell, characterized in that: include: a housing having an open end; a pole group, disposed in the housing; The cover plate assembly according to any one of claims 1 to 9, wherein the cover plate assembly is covered on the open end of the shell.

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