Cover plate structure and battery cell

Abstract

The invention relates to the technical field of batteries, and discloses a cover plate structure and a battery cell, and the cover plate structure comprises a cover plate and a pole assembly. The pole assembly is located between the pole area on the cover plate and the limiting part, limiting of the pole assembly is achieved, the relative stability of the pole assembly and the cover plate is guaranteed, the first grooves are formed in the upper end of the plastic part body, and the first grooves provide extension spaces for the part between every two adjacent first grooves, so that the stability of the plastic part body is improved, and the service life of the plastic part body is prolonged. The ratio of the total projection area S1 of a plurality of first grooves on the upper surface of a pole region to the projection area S0 of a first end surface on the upper surface of the pole region is limited to be 0.15-0.75, and the projection area S0 of the first end surface on the upper surface of the pole region is limited to be 50-1000 mm < 2 >. Therefore, the lower surface of the flange can be well attached to the upper end face of the plastic part main body, the stability of the resistance value between the pole and the cover plate is ensured, and the upper plastic part can be prevented from being damaged due to extrusion.

Description

Technical Field

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

[0002] The cover plate structure is a crucial component of the battery cell. It typically houses the pole, explosion-proof valve, and injection port. A plastic upper and sealing ring are installed between the pole and the cover plate to ensure insulation and sealing between the pole and the cover plate. The resistance between the pole and the cover plate is a key factor in the battery cell acceptance criteria. During the battery cell production process, this resistance must remain stable to ensure a satisfactory cell quality rate.

[0003] However, during the battery cell assembly process, gaps often appear between the upper plastic part and the cover plate, resulting in loose fit and large fluctuations in the resistance between the pole and the cover plate. This leads to unstable resistance, or even resistance exceeding the standard requirements, which reduces the battery cell qualification rate. Summary of the Invention

[0004] In view of this, the present invention provides a cover plate structure and a battery cell to solve the problem of unstable resistance between the electrode and the cover plate.

[0005] In the first aspect, the present invention provides a cover plate structure, comprising: a cover plate, constructed with a pole area and a limiting portion, the pole area being formed by a partial area of the upper surface of the cover plate being recessed downward, a first through hole being opened in the pole area, the limiting portion comprising a limiting wall and a flange, the limiting wall being formed by extending upward from the circumferential edge of the pole area, the flange being connected to the upper end of the limiting wall and being arranged opposite to the pole area; a pole assembly, comprising a pole and an upper plastic part, the pole being arranged corresponding to the pole area, and the upper plastic part being arranged between the pole and The cover plate is fixed relative to the pole, the upper plastic part includes a plastic part body, the upper end of the plastic part body forms a first end face, the first end face abuts the lower surface of the flange, the lower end of the plastic part body abuts the upper surface of the pole area, a plurality of first grooves are provided on the first end face, the projection area of the first end face on the upper surface of the pole area is S0, and the total projection area of the plurality of first grooves on the upper surface of the pole area is S1, wherein 0.15≤S1 / S0≤0.75, 50mm 2 ≤S0≤1000mm 2 .

[0006] Beneficial effect: By constructing a pole area formed by a downward depression of a part of the upper surface of the cover plate and a limiting portion arranged circumferentially around the pole area on the cover plate, the pole assembly is located between the pole area and the limiting portion, the limiting wall of the limiting portion radially limits the pole assembly, and the flange and the pole area jointly limit the pole assembly axially, thereby ensuring the relative stability of the pole assembly and the cover plate, and by setting the pole of the pole assembly to be relatively fixed to the upper plastic part, the integrity of the pole assembly is ensured, and the assembly of the pole assembly and the cover plate is facilitated. At the same time, by opening a hole at the upper end of the plastic part body A plurality of first grooves are provided so that the end surface of the upper plastic part abutting against the lower surface of the flange has an alternating concave and convex structure. When the flange presses down the main body of the plastic part, the first groove provides an extension space for the portion between two adjacent first grooves for abutting against the flange. Furthermore, by limiting the ratio S1 / S0 between the total projected area S1 of the plurality of first grooves on the upper surface of the pole region and the projected area S0 of the first end surface on the upper surface of the pole region to be within the range of 0.15 to 0.75, and the projected area S0 of the first end surface on the upper surface of the pole region is within 50mm. 2 Up to 1000mm 2 Taking the value within the range can not only ensure that the lower surface of the flange is in full and uniform contact with the upper end surface of the plastic body, so that the two fit well together, thereby ensuring the stability of the resistance between the pole and the cover, but also ensure that the plastic body has sufficient strength, thereby avoiding damage to the upper plastic part due to extrusion and improving the reliability of the cover structure.

[0007] In an optional embodiment, the lower end of the plastic body forms a second end face, and a plurality of second grooves are formed on the second end face. The projection area of the second end face on the upper surface of the pole region is S2, and the total projection area of the plurality of second grooves on the upper surface of the pole region is S3, wherein 0.15≤S3 / S2≤0.7, 50mm 2 ≤S2≤1000mm 2 .

[0008] Beneficial effects: It can ensure that the lower end surface of the plastic body and the upper surface of the pole area are in full and uniform contact, so that the two fit well together, thereby ensuring the stability of the resistance between the pole and the cover plate, and can also ensure that the plastic body has sufficient strength, thereby avoiding damage to the upper plastic part due to extrusion, improving the reliability of the cover plate structure, and at the same time ensuring that the battery cell has a high energy density.

[0009] In an optional embodiment, the pole includes a main body section, the diameter of the main body section is larger than the aperture of the first through hole, the plastic part body includes a first ring portion and a first side portion, the first ring portion is located between the upper surface of the main body section and the lower surface of the flange, the upper surface of the first ring portion forms the first end face, the first side portion is connected to the outer ring of the first ring portion and is located between the outer peripheral surface of the main body section and the limiting wall, the total thickness dimension of the first ring portion along the up and down direction is L0, and the thickness of the solid part of the first ring portion corresponding to the first groove along the up and down direction is L1, wherein 0.4≤L1 / L0≤0.95.

[0010] Beneficial effect: It can ensure that the first ring has good strength, ensure that the upper plastic part is not crushed, and ensure the insulation of the upper plastic part, and can also ensure that the resistance between the pole and the cover is stable and the resistance value meets the standard, thereby improving the safety and stability of the battery cell.

[0011] In an optional embodiment, a total thickness dimension L0 of the first ring portion along the up-down direction has a value range of: 0.5 mm ≤ L0 ≤ 1.5 mm.

[0012] Beneficial effects: It can ensure that the first ring has sufficient structural strength to prevent the upper plastic part from being crushed, and ensure that the upper plastic part has high insulation, while reducing costs and ensuring the energy density of the battery cell.

[0013] In an optional embodiment, a limiting groove is provided on the inner side of the limiting portion, and a limiting block is constructed on the outer side of the plastic body, and the limiting block cooperates with the limiting groove.

[0014] Beneficial effect: By opening a limiting groove on the inner side of the limiting part and constructing a limiting block corresponding to the limiting groove on the outer side of the plastic body, the limiting block is embedded in the limiting groove. Through the cooperation between the limiting block and the limiting groove, the relative rotation between the upper plastic part and the limiting part is avoided, thereby improving the stability of the pole assembly and the cover plate after assembly.

[0015] In an optional embodiment, the limiting groove includes a first groove portion opened on the inner side of the limiting wall and a second groove portion opened on the lower side of the flange, and the first groove portion is connected to the second groove portion; the limiting block includes a first protrusion portion connected to the outer peripheral surface of the first side portion and a second protrusion portion connected to the first end face, the first protrusion portion is connected to the second protrusion portion, the first protrusion portion cooperates with the first groove portion, and the second protrusion portion cooperates with the second groove portion.

[0016] Beneficial effect: By arranging the first protrusion to cooperate with the first groove, the relative fixation of the positional relationship between the first side portion and the limiting wall is achieved, and the first side portion and the limiting wall are prevented from rotating relative to each other around the center line of the first through hole. By cooperating with the second protrusion and the second groove, the relative fixation between the first ring portion and the flange is achieved, and the relative rotation between the first ring portion and the flange around the center line of the first through hole is avoided, thereby ensuring the relative rotation between the upper plastic part and the limiting portion around the center line of the first through hole, that is, ensuring the relative stability between the pole assembly and the cover plate, preventing the cover plate structure from loosening, and improving the reliability of the cover plate structure.

[0017] In an optional embodiment, the wall thickness of the first side portion is H0, and the dimension of the first protrusion protruding from the outer circumference of the first side portion along the wall thickness direction of the first side portion is H1, wherein 0.1≤H1 / H0≤0.6;

[0018] and / or, a dimension H1 of the first protrusion protruding from the outer peripheral surface of the first side portion in a wall thickness direction of the first side portion is in the range of: 0.15 mm ≤ H1 ≤ 2 mm;

[0019] And / or, a dimension of the second protrusion along the up-down direction is H2, wherein 0.2 mm ≤ H2 ≤ 2 mm.

[0020] Beneficial effect: By setting H1 / H0 to a value within the range of 0.1 to 0.6, it can be ensured that the first anti-rotation structure formed by the cooperation of the first protrusion and the first groove has a good anti-rotation effect, thereby improving the relative stability between the pole assembly and the cover plate, and can also ensure that the first protrusion has a reasonable size, thereby ensuring that the limiting wall is smoothly formed, thereby ensuring that the limiting part has a high forming yield and saving costs.

[0021] By setting the dimension H1 of the first protrusion protruding from the outer peripheral surface of the first side portion in the wall thickness direction of the first side portion to be in the range of 0.15mm to 2mm, it can be ensured that the first protrusion has sufficient thickness, thereby ensuring that the first anti-rotation structure composed of the first protrusion and the first groove has a better anti-rotation effect, and can avoid the formation of the limiting wall being affected by the excessive thickness of the first protrusion and the excessive depth of the first groove, thereby ensuring the forming yield of the limiting portion and reducing production costs.

[0022] By setting the dimension H2 of the second protrusion in the up and down direction to be in the range of 0.2mm to 2mm, it can be ensured that the second anti-rotation structure formed by the cooperation of the second protrusion and the second groove has a better anti-rotation effect, thereby improving the relative stability between the pole assembly and the cover plate, and can also ensure that the second protrusion and the second groove have reasonable sizes, thereby ensuring that the flange is smoothly formed, thereby ensuring that the limiting part has a higher forming yield and saving production costs.

[0023] In an optional embodiment, the number of the limiting blocks is one or more, and the number of the limiting grooves is equal to and corresponds one to one to the number of the limiting blocks.

[0024] Beneficial effects: The number of limit blocks and limit slots is one, and the limit slot and the limit block cooperate to form a rotation-stopping structure, which has a simple structure, is easy to process, and has low cost; by setting the number of limit blocks and limit slots to be multiple, multiple limit slots and multiple limit blocks correspond one to one to form multiple rotation-stopping structures, which can further enhance the rotation-stopping effect and improve the relative stability between the pole assembly and the cover plate.

[0025] In an optional embodiment, the pole further includes a first column segment, the first column segment is connected to the upper end of the main body segment and the diameter of the first column segment is smaller than the diameter of the main body segment, and the upper plastic part further includes a second side portion, the second side portion is connected to the inner ring of the first ring portion and is located between the outer peripheral wall of the first column segment and the inner peripheral wall of the flange;

[0026] And / or, a first anti-rotation portion is configured on an outer circumference of the main body section, a second anti-rotation portion is configured on an inner circumference of the first side portion, and the first anti-rotation portion is engaged with the second anti-rotation portion;

[0027] And / or, the lower end of the plastic body is lower than the lower surface of the main body section, and the distance between the lower surface of the main body section and the lower end of the plastic body in the up-down direction is L2, wherein 0.5 mm ≤ L2 ≤ 2 mm.

[0028] Beneficial effect: By setting the pole to also include a first column segment connected to the upper end of the main body segment, and the diameter of the first column segment is smaller than the diameter of the main body segment, so that the main body segment is limited below the flange, the first column segment can pass through the second through hole surrounded by the inner ring of the flange, thereby facilitating the connection of the pole with structural parts such as the busbar outside the battery cell. At the same time, by setting the upper plastic part to also include a second side portion connected to the inner ring of the first ring portion, the second side portion is located between the first column segment and the flange, which can enhance the insulation between the pole and the cover plate.

[0029] By constructing a first anti-rotation portion on the outer peripheral side of the main section and a second anti-rotation portion corresponding to the first anti-rotation portion on the inner peripheral side of the first side portion, the first anti-rotation portion and the second anti-rotation portion are snap-fitted to form a third anti-rotation structure, thereby avoiding relative rotation between the pole and the upper plastic part, thereby achieving relative fixation of the pole and the upper plastic part, improving the stability of the pole assembly, and the pole assembly is assembled with the cover plate as a whole, which is easy to operate and improves assembly efficiency.

[0030] By setting the distance L2 between the lower surface of the main section and the lower end of the plastic body in the vertical direction to be in the range of 0.5mm to 2mm, the sealing ring is ensured to have a reasonable compression amount, which can not only ensure the sealing performance and the service life of the sealing ring, but also avoid the overall size of the pole assembly in the vertical direction being too large, saving costs and improving the volume energy density of the battery cell.

[0031] In a second aspect, the present invention further provides a battery cell comprising: a housing having an open end; an electrode group disposed within an inner cavity of the housing; and the aforementioned cover plate structure disposed at the open end of the housing. Because the battery cell includes the cover plate structure, it has the same effects as the cover plate structure and will not be further described here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 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.

[0033] Figure 1 A top view of a cover plate structure according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A cross-sectional view of the cover plate structure in the AA direction shown;

[0035] Figure 3 for Figure 2 A partial enlarged schematic diagram of the middle M;

[0036] Figure 4 is a cross-sectional view of another cover plate structure according to an embodiment of the present invention;

[0037] Figure 5 for Figure 4 A partial enlarged schematic diagram of N in the middle;

[0038] Figure 6 This is a structural schematic diagram of a cover plate according to an embodiment of the present invention;

[0039] Figure 7 for Figure 6 A partial enlarged schematic diagram of P in the middle;

[0040] Figure 8 for Figure 6 a top view of the cover plate shown;

[0041] Figure 9 for Figure 8 A cross-sectional view of the cover plate taken along the BB direction;

[0042] Figure 10 This is a schematic structural diagram of a pole assembly according to an embodiment of the present invention;

[0043] Figure 11 for Figure 10 A schematic structural diagram of the pole assembly from a bottom perspective is shown;

[0044] Figure 12 for Figure 10 A top view of the pole assembly is shown;

[0045] Figure 13 for Figure 12 Cross-sectional view in CC direction;

[0046] Figure 14 for Figure 12 Cross-sectional view in the middle DD direction;

[0047] Figure 15 for Figure 10 The schematic diagram of the structure of the upper plastic part in the pole assembly shown;

[0048] Figure 16 for Figure 15 The schematic structural diagram of the upper plastic part shown is from the bottom perspective;

[0049] Figure 17 This is a schematic structural diagram of another pole assembly according to an embodiment of the present invention;

[0050] Figure 18 for Figure 17 A top view of the pole assembly is shown;

[0051] Figure 19 for Figure 18 Cross-sectional view in the EE direction;

[0052] Figure 20 for Figure 17 The schematic diagram of the structure of the upper plastic part in the pole assembly shown;

[0053] Figure 21 This is a schematic structural diagram of a pole according to an embodiment of the present invention;

[0054] Figure 22 for Figure 21 A schematic structural diagram of the pole from the bottom perspective is shown.

[0055] Description of reference numerals:

[0056] 1. Cover plate; 110. Pole area; 101. First through hole; 120. Limiting portion; 121. Limiting wall; 122. Flanging; 102. Second through hole; 130. Limiting groove; 131. First groove portion; 132. Second groove portion; 2. Pole; 210. Main body section; 211. First anti-rotation portion; 220. First column section; 230. Second column section; 240. Boss; 241. Positioning hole; 3. Upper plastic part; 310. Plastic part body; 311. First end face; 3111. First groove; 312. Second end face; 3121. Second groove; 301. First ring portion; 302. First side portion; 303. Hook portion; 304. Second anti-rotation portion; 320. Second side portion; 330. Limit block; 331. First protrusion; 332. Second protrusion; 4. Sealing ring; 5. Lower plastic part. DETAILED DESCRIPTION

[0057] 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.

[0058] The following combination Figures 1 to 22 , describing embodiments of the present invention.

[0059] According to an embodiment of the present invention, on the one hand, a cover plate structure is provided, including: a cover plate 1 and a pole assembly. The cover plate 1 is constructed with a pole area 110 and a limiting portion 120. The pole area 110 is formed by a portion of the upper surface of the cover plate 1 being recessed downward. A first through hole 101 is provided in the pole area 110. The limiting portion 120 includes a limiting wall 121 and a flange 122. The limiting wall 121 is formed by an upward extension of the circumferential edge of the pole area 110. The flange 122 is connected to the upper end of the limiting wall 121 and is arranged opposite to the pole area 110. The pole assembly includes a pole 2 and an upper plastic part 3. The pole 2 is arranged corresponding to the pole area 110. The upper plastic part 3 is arranged between the pole 2 and the cover plate 1 and is opposite to the pole area 110. The column 2 is relatively fixed, and the upper plastic part 3 includes a plastic part body 310. The upper end of the plastic part body 310 forms a first end face 311, and the first end face 311 abuts against the lower surface of the flange 122. The lower end of the plastic part body 310 abuts against the upper surface of the pole area 110. A plurality of first grooves 3111 are formed on the first end face 311. The projected area of the first end face 311 on the upper surface of the pole area 110 is S0, and the total projected area of the plurality of first grooves 3111 on the upper surface of the pole area 110 is S1, wherein 0.15≤S1 / S0≤0.75, 50mm 2 ≤S0≤1000mm 2 .

[0060] The upper surface refers to Figures 2 to 5 The upper surface of the cover plate 1 is the large surface on the cover plate 1 facing the outside of the battery housing; the lower surface is the surface in the direction of the “upper” indicated by the middle arrow. Figures 2 to 5 The arrow in the middle points to the surface in the direction of "down"; down means toward Figures 2 to 5 The middle arrow points to the direction of "down"; upward refers to the direction Figures 2 to 5 The arrow in the middle points to the direction of "up"; the upper end refers to Figures 2 to 5 The projection of the first end face 311 on the upper surface of the pole area 110 refers to the end in the direction of "up" indicated by the arrow; Figures 2 to 5 In the direction of "up and down" indicated by the middle arrow, the first end face 311 is the orthographic projection of the first end face 311 on the pole area 110 along the projection direction from top to bottom. The first end face 311 is the upper end face of the first ring portion 301. The orthographic projection of the first end face 311 on the pole area 110 is the area of the ring enclosed by the orthographic projections of the inner ring and the outer ring of the first ring portion 301 on the upper surface of the pole area 110; the projection of the first groove 3111 on the upper surface of the pole area 110 is the orthographic projection of the first groove 3111 on the pole area 110 according to the projection direction from "up" to "down".

[0061] The cover plate structure of this embodiment is applied, by constructing a pole area 110 formed by a downward depression of a part of the upper surface of the cover plate 1 and a limiting portion 120 circumferentially arranged around the pole area 110 on the cover plate 1, the pole assembly is located between the pole area 110 and the limiting portion 120, the limiting wall 121 of the limiting portion 120 radially limits the pole assembly, and the flange 122 and the pole area 110 jointly limit the pole assembly axially, ensuring the relative stability of the pole assembly and the cover plate 1, and by setting the pole 2 of the pole assembly to be relatively fixed to the upper plastic part 3, the integrity of the pole assembly is ensured, and the assembly of the pole assembly and the cover plate 1 is facilitated. At the same time, by opening a hole at the upper end of the plastic part main body 310 The first grooves 3111 are provided so that the end surface of the upper plastic part 3 abutting against the lower surface of the flange 122 has an alternating concave and convex structure. When the flange 122 presses down the plastic part body 310, the first grooves 3111 provide an extension space for the portion between two adjacent first grooves 3111 for abutting against the flange 122. Furthermore, by limiting the ratio S1 / S0 between the total projected area S1 of the first grooves 3111 on the upper surface of the pole region 110 and the projected area S0 of the first end surface 311 on the upper surface of the pole region 110 to be within the range of 0.15 to 0.75, and the projected area S0 of the first end surface 311 on the upper surface of the pole region 110 is within 50 mm. 2 Up to 1000mm 2Taking a value within the range can ensure that the lower surface of the flange 122 is in full and uniform contact with the upper end surface of the plastic body 310, so that the two fit well together, thereby ensuring the stability of the resistance between the pole 2 and the cover 1, and can also ensure that the plastic body 310 has sufficient strength, thereby preventing the upper plastic part 3 from being damaged by extrusion, and improving the reliability of the cover structure.

[0062] Preferably, the orthographic projection of the pole 2 on a cross section perpendicular to its centerline is a circle, radial limitation refers to limitation along the radial direction of the circle, and axial limitation refers to limitation along the direction of the centerline of the pole 2.

[0063] It should be noted that before the cover structure is assembled, the limiting portion 120 is generally tubular and perpendicular to the upper surface of the cover 1, and no flange 122 is formed. During the assembly process, the pole assembly is first placed in the pole area 110, and then the flange 122 is processed by riveting to press the plastic body 310 and a portion of the pole 2 between the flange 122 and the pole area 110, thereby fixing the pole assembly. The flange 122 is bent from a portion of the upper end of the tubular limiting portion toward the direction close to the center line of the first through hole 101, and the flange 122 is annular and the upper and lower surfaces of the flange 122 are parallel to the upper surface of the pole area 110. The upper plastic part 3 will be subjected to a certain extrusion force in the up and down directions.

[0064] A plurality of first grooves 3111 are provided on the first end surface of the upper plastic part 3. The portion between two adjacent first grooves 3111 forms a first abutting portion that protrudes upward relative to the bottom wall of the first groove 3111. The first abutting portion is used to contact the lower surface of the flange 122. If S1 / S0 is less than 0.15, the ratio of the groove area on the first end surface 311 of the upper plastic part 3 to the total area of the first end surface 311 is too small, the area of the portion of the first end surface 311 that is used to contact the lower surface of the flange 122 accounts for too large a proportion, and the contact area between the first end surface 311 and the flange 122 of the cover plate 1 is too large. During the process of forming the flange 122 by spin riveting, the first end surface 31 1 is subjected to the extrusion force from the flange 122, and the first grooves 3111 cannot provide sufficient expansion space for the first abutting portion. The area on the first end surface 311 that contacts the flange 122 will have irregular wrinkles due to the extrusion. The first end surface 311 and the lower surface of the flange 122 cannot fit well, and there is a gap, resulting in unstable resistance between the pole 2 and the cover plate 1. If S1 / S0 is greater than 0.75, the groove area on the first end surface 311 is too large, the contact area between the first end surface 311 and the flange 122 is too small, and the strength of the first abutting portion on the first end surface 311 for abutting the flange 122 is low, and the upper plastic part 3 is easily damaged. Wherein, the units of S1 and S0 are both mm 2 .

[0065] The first end face 311 is the upper end face of the plastic body 310. If S0 is less than 50 mm 2 If the area of the upper end surface of the plastic body 310 is too small, the ring width of the first ring portion 301 is too small. Correspondingly, the structural strength of the plastic body 310 is insufficient, and the upper plastic part 3 is easily crushed. Alternatively, the outer ring size of the first ring portion 301 is too small. Correspondingly, the size of the pole 2 is too small and the flow capacity is insufficient. If S0 is greater than 1000mm 2 , the area of the upper end surface of the plastic body 310 is too large, the ring width of the first ring portion 301 is too large, and correspondingly, the diameter of the boss 240 on the pole 2 is too small, and the current carrying capacity of the pole 2 is insufficient. Alternatively, the outer ring size of the first ring portion 301 is too large, and correspondingly, the size and weight of the pole 2 are too large, which is not conducive to improving the energy density of the battery cell.

[0066] Preferably, the plurality of first grooves 3111 are distributed at equal intervals around the circumference of the plastic component body 310 to ensure uniform force on the first end surface 311 .

[0067] Preferably, the upper end of the limiting wall 121 protrudes from the upper surface of the cover plate 1 to ensure that there is enough space between the flange 122 and the pole area 110 to accommodate the pole assembly, thereby ensuring that the pole 2 has a sufficient size to meet the overcurrent requirement.

[0068] Preferably, the upper plastic part 3 is upper plastic.

[0069] Battery cells were assembled using upper plastic parts 3 with different S1 / S0 ratios. The resistance between the pole 2 and the cover 1 was tested. After the test, the battery cells were disassembled to observe whether the upper plastic parts were damaged. This verified the effect of different S1 / S0 ratios on battery cell performance. The verification results are shown in Table 1.

[0070] Table 1 Effect of different S1 / S0 values on cell performance

[0071]

[0072] It should be noted that each implementation case or comparison case includes several battery cells. After testing several battery cells one by one, the results of the implementation cases or comparison cases are statistically analyzed. In the table, CPK (Complex Process Capability Index) is an indicator used to measure the manufacturing process capability, reflecting the level of process qualification rate; the resistance value meets the standard means that the resistance between the electrode 2 and the cover plate 1 meets the standard requirements for product production. Specifically, for the negative electrode, the resistance between the negative electrode and the cover plate 1 is required to be greater than or equal to 200MΩ, and for the positive electrode, the resistance between the positive electrode and the cover plate 1 is required to be between 5Ω and 10000Ω.

[0073] As can be seen from Table 1, for the cells of Example 1 to Example 10, S1 / S0 is in the range of 0.15 to 0.75, and S0 is in the range of 50 mm. 2 Up to 1000mm 2 The range is as follows: that is, the values of S1 / S0 and S0 are within the range specified in this application, the resistance between the pole and the cover conforms to the normal distribution, the resistance value meets the standard, and CPK≥1.33. After disassembly, no damage to the upper plastic part was found. For the battery cell of comparative case 1, the value of S1 / S0 is 0, that is, the first end surface 311 of the upper plastic part 3 does not have the first groove 3111, which is not within the range specified in this application. The contact area between the upper plastic part and the flange is too large and cannot be well fitted. The resistance between the pole and the cover is highly discrete, CPK<1.33, and there is In the case of individual resistance values exceeding the standard, it is not recommended to use; for the battery cell of comparative case 2, the value of S1 / S0 is 0.1, which is less than 0.15 and is not within the range specified in this application. The contact area between the upper plastic part and the flange is large and cannot fit well. The resistance between the pole and the cover plate is highly discrete, CPK < 1.33, and it is not recommended to use; for the battery cell of comparative case 3, the value of S1 / S0 is 0.9, which is greater than 0.75 and is not within the range specified in this application. The contact area between the upper plastic part and the cover plate is small and the strength is low. After disassembly, it was found that the upper plastic part was damaged. In summary, when the ratio S1 / S0 between the total projected area S1 of the plurality of first grooves 3111 on the upper surface of the pole area 110 and the projected area S0 of the first end face 311 on the upper surface of the pole area 110 is within the range of 0.15 to 0.75, and the projected area S0 of the first end face 311 on the upper surface of the pole area 110 is within 50mm 2 Up to 1000mm 2 When the value is within the range, it can ensure that the lower surface of the flange 122 fits well with the upper end surface of the plastic body 310, thereby ensuring the stability of the resistance between the pole 2 and the cover 1, and can also ensure that the plastic body 310 has sufficient strength, thereby preventing the upper plastic part 3 from being damaged due to extrusion.

[0074] In one embodiment, the lower end of the plastic body 310 forms a second end surface 312, and a plurality of second grooves 3121 are formed on the second end surface 312. The projected area of the second end surface 312 on the upper surface of the pole area 110 is S2, and the total projected area of the plurality of second grooves 3121 on the upper surface of the pole area 110 is S3, where 0.15≤S3 / S2≤0.7, 50mm 2 ≤S2≤1000mm 2 Among them, the lower end refers to Figures 2 to 5The end in the direction of "down" indicated by the middle arrow; the projection of the second end face 312 on the upper surface of the pole area 110 refers to the orthographic projection of the second end face 312 on the pole area 110. The second end face 312 is annular, and the orthographic projection of the second end face 312 on the pole area 110 is the area of the ring enclosed by the orthographic projections of the inner ring and outer ring of the ring of the second end face 312 on the upper surface of the pole area 110. Among them, the units of S3 and S2 are both mm 2 .

[0075] It should be noted that the plastic body 310 and the part of the pole wrapped by the plastic body 310 are limited between the flange 122 and the pole area 110, and the plastic body 310 is affected by the Figures 2 to 5 The extrusion force in the "up and down" direction indicated by the middle arrow, the second end surface 312 located at the lower end of the plastic part body 310 contacts the upper surface of the pole area 110 under the action of the extrusion force; a plurality of second grooves 3121 are provided on the second end surface 312, and the second end surface 312 has a concave-convex alternating structure, and the portion between two adjacent second grooves 3121 forms a second abutting portion that protrudes downward relative to the bottom wall of the second groove 3121, and the lower surface of the second abutting portion is used to contact the upper surface of the pole area 110. If S3 / S2 is less than 0.15, the ratio of the groove area on the second end surface 312 to the total area of the second end surface 312 is too small, and the area of the portion of the second end surface 312 used for contacting the pole area 110 is too large, and the second end surface 312 and the upper surface of the pole area 110 are in contact. The contact area between the surfaces is too large. When the second end face 312 is subjected to an extrusion force in the up and down directions during the assembly of the cover structure, the several second grooves 3121 cannot provide sufficient extension space for the second abutting portion. The area on the second end face 312 that contacts the pole area 110 will appear wrinkled due to the extrusion. The second end face 312 and the upper surface of the pole area 110 cannot fit well, and there is an irregular gap. The fit is not tight, resulting in unstable resistance between the pole 2 and the cover 1; if S3 / S2 is greater than 0.7, the groove area on the second end face 312 is too large, the contact area between the second end face 312 and the upper surface of the pole area 110 is too small, the strength of the second abutting portion on the second end face 312 for abutting the pole area 110 is low, and the upper plastic part 3 is easily damaged.

[0076] In addition, the second end surface 312 is the lower end surface of the plastic body 310. If the projection area S2 of the second end surface 312 on the upper surface of the pole area 110 is less than 50 mm 2 , the area of the lower end surface of the plastic body 310 is too small, the structural strength of the plastic body 310 is insufficient, and the upper plastic part 3 is easily crushed; if S2 is greater than 1000mm 2 , the area of the lower end surface of the plastic body 310 is too large, occupying too much space on the cover plate 1, affecting the design of other components on the cover plate 1, and is not conducive to improving the energy density of the battery cell.

[0077] Therefore, by setting the ratio of the total projected area S3 of the plurality of second grooves 3121 on the upper surface of the pole region 110 to the projected area S2 of the second end surface 312 on the upper surface of the pole region 110, the ratio is in the range of 0.15 to 0.7, and S2 is 50 mm. 2 Up to 1000mm 2 Taking values within the range can not only ensure that the lower end surface of the plastic body 310 is in sufficient and uniform contact with the upper surface of the pole area 110, so that the two fit well together, thereby ensuring the stability of the resistance between the pole 2 and the cover 1, but also ensure that the plastic body 310 has sufficient strength, thereby avoiding damage to the upper plastic part 3 due to squeezing, improving the reliability of the cover structure, and ensuring that the battery cell has a high energy density.

[0078] Preferably, the plurality of second grooves 3121 are distributed at equal intervals around the circumference of the plastic component body 310 to ensure uniform force on the second end surface 312 .

[0079] Battery cells were assembled using upper plastic parts 3 with different S3 / S2 ratios. The resistance between the pole 2 and the cover 1 was tested. After the test, the battery cells were disassembled to observe whether the upper plastic part 3 was damaged. This verified the effect of different S3 / S2 values on battery cell performance. The verification results are shown in Table 2.

[0080] Table 2 Effects of different S3 / S2 values on cell performance

[0081]

[0082] As can be seen from Table 2, for the cells of Example 11 to Example 20, S3 / S2 are all in the range of 0.15 to 0.7, and S2 is all in the range of 50 mm. 2 Up to 1000mm 2The range is as follows: that is, the values of S3 / S2 and S2 are within the range specified in this application, the resistance between the pole and the cover conforms to the normal distribution, the resistance value meets the standard, and CPK≥1.33. No damage to the upper plastic part was found after disassembly; while for the battery cell of comparative case 4, the value of S3 / S2 is 0, that is, the second end face 312 of the upper plastic part 3 does not have the second groove 3121, which is not within the range specified in this application. The contact area between the upper plastic part and the pole area is too large and cannot be well fitted. The resistance between the pole and the cover is highly discrete, CPK<1.33, and there is In the case of individual resistance values exceeding the standard, it is not recommended for use; for the battery cell of comparative case 5, the value of S3 / S2 is 0.1, which is less than 0.15 and is not within the range specified in this application. The contact area between the upper plastic part and the pole area is large and cannot fit well. The resistance between the pole and the cover plate is highly discrete, CPK < 1.33, and it is not recommended for use; for the battery cell of comparative case 6, the value of S3 / S2 is 0.9, which is greater than 0.7 and is not within the range specified in this application. The contact area between the upper plastic part and the pole area is small and the strength is low. After disassembly, it was found that the upper plastic part was damaged. In summary, when the ratio between the total projected area S3 of the plurality of second grooves 3121 on the upper surface of the pole area 110 and the projected area S2 of the second end face 312 on the upper surface of the pole area 110 is in the range of 0.15 to 0.7, and S2 is within 50mm 2 Up to 1000mm 2 Taking the value within the range can ensure that the lower end surface of the plastic body 310 fits well with the upper surface of the pole area 110, thereby ensuring the stability of the resistance between the pole 2 and the cover 1, and can also ensure that the plastic body 310 has sufficient strength, thereby preventing the upper plastic part 3 from being damaged due to extrusion.

[0083] In one embodiment, the pole 2 includes a main body section 210, the diameter of the main body section 210 is larger than the aperture of the first through hole 101, and the plastic body 310 includes a first ring portion 301 and a first side portion 302. The first ring portion 301 is located between the upper surface of the main body section 210 and the lower surface of the flange 122. The upper surface of the first ring portion 301 forms a first end face 311. The first side portion 302 is connected to the outer ring of the first ring portion 301 and is located between the outer peripheral surface of the main body section 210 and the limiting wall 121. The total thickness dimension of the first ring portion 301 in the up-down direction is L0. The thickness of the entity portion of the first ring portion 301 corresponding to the first groove 3111 in the up-down direction is L1, wherein 0.4≤L1 / L0≤0.95. Wherein, the up-down direction refers to Figure 3 and Figure 13 The “up and down” directions indicated by the middle arrows; the outer peripheral surface of the main body segment 210 refers to the circumferential surface of the main body segment 210 .

[0084] It should be noted that the main section 210 is located between the pole area 110 and the limiting portion 120, the main section 210 is cylindrical, and the first through hole 101 is a circular hole. By setting the diameter of the main section 210 of the pole 2 to be larger than the aperture of the first through hole 101, the main section 210 is limited between the pole area 110 and the flange 122. The main section 210 is indirectly in contact with the flange 122 through the first ring portion 301 of the plastic body 310, and the first ring portion 301 is subjected to an extrusion force in the up and down directions; a plurality of first grooves 3111 are provided on the first ring portion 301, L0 refers to the total thickness of the ungrooved portion of the first ring portion 301 in the up and down directions, and L1 refers to the thickness of the solid portion remaining in the up and down directions at the grooved position on the first ring portion 301 after removing the first grooves 3111. If L1 / L0 is less than 0.4, the thickness of the remaining entity part after removing the first groove 3111 on the first ring part 301 is too small relative to the total thickness of the first ring part 301, the depression depth of the first groove 3111 in the up-down direction is too large, the thickness of the slot is too small, it is easy to be crushed, and the insulation performance of the upper plastic part 3 is poor, which is very dangerous; if L1 / L0 is greater than 0.95, the thickness of the remaining entity part after removing the first groove 3111 on the first ring part 301 is too large relative to the total thickness of the first ring part 301, the depression depth of the first groove 3111 in the up-down direction is too small, the first groove 3111 cannot provide sufficient space for the extension of the first support part, and there is still a situation where the first end face 311 and the lower surface of the flange 122 are not tightly fitted, resulting in unstable resistance between the pole 2 and the cover plate 1.

[0085] Therefore, by limiting the ratio of the thickness L1 of the solid part of the first ring portion 301 corresponding to the first groove 3111 in the up-down direction to the total thickness L0 of the first ring portion 301 in the up-down direction to be within the range of 0.4 to 0.95, it is possible to ensure that the first ring portion 301 has good strength, ensure that the upper plastic part 3 is not crushed, and ensure the insulation of the upper plastic part 3, and ensure that the resistance between the pole 2 and the cover plate 1 is stable and the resistance value meets the standard, thereby improving the safety and stability of the battery cell.

[0086] In one embodiment, the total thickness dimension L0 of the first ring portion 301 in the vertical direction ranges from 0.5 mm to 1.5 mm. If L0 is less than 0.5 mm, the first ring portion 301 is too thin, has weak structural strength, is easily crushed, and has weak voltage resistance. If L0 is greater than 1.5 mm, the first ring portion 301 is too thick, heavy, and expensive, and occupies too much space in the vertical direction. Accordingly, the dimension of the limiting wall 121 in the vertical direction needs to be increased, which increases the overall dimension of the battery cell in the vertical direction, which is not conducive to improving the volume energy density of the battery cell. Therefore, by setting the total thickness dimension L0 of the first ring portion 301 in the vertical direction within the range of 0.5 mm to 1.5 mm, it is possible to ensure that the first ring portion 301 has sufficient structural strength, prevent the upper plastic part 3 from being crushed, and ensure that the upper plastic part 3 has high insulation properties, while also reducing costs and ensuring the energy density of the battery cell.

[0087] Cells were assembled using upper plastic parts 3 with different L1 / L0 ratios. These cells were then subjected to a withstand voltage test, and the resistance between the pole 2 and the cover plate 1 was measured. After the test, the cells were disassembled to inspect the upper plastic parts for damage. This verified the effect of different L1 / L0 ratios on cell performance. The results are shown in Table 3. The withstand voltage test examined the insulation between the pole 2 and the cover plate 1. Specifically, a 1500VDC voltage was applied between the pole 2 and the cover plate 1, with a leakage current requirement of 2mA or less.

[0088] Table 3 Effects of different L1 / L0 values on cell performance

[0089]

[0090] It can be seen from Table 3 that for the battery cells of Implementation Cases 21 to 30, L1 / L0 is in the range of 0.4 to 0.95, and L0 is in the range of 0.5 mm to 1.5 mm, that is, the values of L1 / L0 and L0 are within the range specified in this application, the battery cell withstand voltage test is OK (passed), the upper plastic part is not damaged after disassembly, the resistance between the pole and the cover conforms to the normal distribution, the resistance value meets the standard, and CPK ≥ 1.33; while for the battery cell of Comparative Case 7, the value of L1 / L0 is 0.3, less than 0.4, not within the range specified in this application, the withstand voltage test NG (failed), and after disassembly, it was found that the groove on the first end face of the upper plastic part was slightly crushed; for the battery cell of comparative case 8, the value of L1 / L0 was 1, that is, the first groove 3111 was not provided on the first end face 311, which was not within the range specified in this application, the withstand voltage test was OK, and after disassembly, the upper plastic part was not damaged, but the resistance between the pole and the cover plate was highly discrete, CPK < 1.33, and there were individual resistance values that exceeded the tolerance (that is, exceeded the standard requirements). In summary, when the ratio of the thickness L1 of the solid portion of the first ring portion 301 corresponding to the first groove 3111 in the up-down direction to the total thickness dimension L0 of the first ring portion 301 in the up-down direction is in the range of 0.4 to 0.95, and the total thickness dimension L0 of the first ring portion 301 in the up-down direction is in the range of 0.5 mm to 1.5 mm, it can be ensured that the first ring portion 301 has good strength, the upper plastic part 3 is not crushed, and the upper plastic part 3 has high insulation, and it can also be ensured that the resistance between the pole 2 and the cover plate 1 is stable and the resistance value meets the standard.

[0091] In one embodiment, a limiting groove 130 is defined on the inner side of the limiting portion 120, and a limiting block 330 is configured on the outer side of the plastic body 310, with the limiting block 330 cooperating with the limiting groove 130. The inner side of the limiting portion 120 refers to the side of the limiting portion 120 facing the pole area 110, and the outer side of the plastic body 310 refers to the side of the plastic body 310 facing the limiting portion 120. By defining the limiting groove 130 on the inner side of the limiting portion 120 and configuring the limiting block 330 corresponding to the limiting groove 130 on the outer side of the plastic body 310, the limiting block 330 is embedded in the limiting groove 130. The cooperation between the limiting block 330 and the limiting groove 130 prevents relative rotation between the upper plastic component 3 and the limiting portion 120, thereby improving the stability of the assembled pole assembly and the cover plate 1.

[0092] In one embodiment, the limiting groove 130 includes a first groove portion 131 opened on the inner side of the limiting wall 121 and a second groove portion 132 opened on the lower side of the flange 122, and the first groove portion 131 is connected to the second groove portion 132; the limiting block 330 includes a first protrusion portion 331 connected to the outer peripheral surface of the first side portion 302 and a second protrusion portion 332 connected to the first end face 311, the first protrusion portion 331 is connected to the second protrusion portion 332, the first protrusion portion 331 cooperates with the first groove portion 131, and the second protrusion portion 332 cooperates with the second groove portion 132. The limiting groove 130 is generally "L"-shaped, and the limiting block 330 is generally "L"-shaped. By providing a first protrusion 331 to cooperate with the first groove 131, the relative fixation of the positional relationship between the first side portion 302 and the limiting wall 121 is achieved, and the first side portion 302 and the limiting wall 121 are prevented from rotating relative to each other around the center line of the first through hole 101. The second protrusion 332 cooperates with the second groove 132 to achieve relative fixation between the first ring portion 301 and the flange 122, and the relative rotation between the first ring portion 301 and the flange 122 around the center line of the first through hole 101 is avoided, thereby ensuring the relative rotation between the upper plastic part 3 and the limiting portion 120 around the center line of the first through hole 101, that is, ensuring the relative stability between the pole assembly and the cover plate 1, preventing the cover plate structure from loosening, and improving the reliability of the cover plate structure.

[0093] It should be noted that the pole assembly on the cover structure includes a positive pole assembly (such as Figures 10 to 14 As shown) and the negative column assembly (as Figures 17 to 19 As shown), polarity markings can be provided on the first raised portion 331 and / or the second raised portion 332 of the limit block 330 to facilitate distinguishing between positive and negative poles and to prevent the positive and negative poles from being reversed when the pole assembly is installed on the cover plate 1.

[0094] In one embodiment, further combined Figure 14 As shown, the wall thickness of the first side portion 302 is H0, and the dimension of the first protrusion 331 protruding from the outer peripheral surface of the first side portion 302 along the wall thickness direction of the first side portion 302 is H1, wherein 0.1≤H1 / H0≤0.6. Figure 14 In the cross section, the wall thickness direction of the first side portion 302 refers to Figure 14 The "first direction" indicated by the arrow is the radial direction of pole 2; the units of H1 and H0 are both mm 2If H1 / H0 is less than 0.1, the dimension of the first protrusion 331 protruding from the outer circumference of the first side portion 302 is too small relative to the wall thickness of the first side portion 302, the thickness of the first protrusion 331 along the first direction is too thin, and correspondingly, the groove depth of the first groove portion 131 is too small. The anti-rotation effect of the first protrusion 331 after cooperation with the first groove portion 131 is poor, and the first side portion 302 of the upper plastic part 3 and the limiting wall 121 of the limiting portion 120 may rotate relative to each other, resulting in poor stability between the pole assembly and the cover plate 1 and poor battery cell performance. If H1 / H0 is greater than 0.6, the dimension of the first protrusion 331 protruding from the outer circumference of the first side portion 302 is too large relative to the wall thickness of the first side portion 302, the first protrusion 331 is too thick along the first direction, and correspondingly, the groove depth of the first groove portion 131 is too large, the wall thickness of the remaining portion of the limiting wall 121 corresponding to the first groove portion 131 is too small, and the molding yield is poor.

[0095] Therefore, by setting H1 / H0 to a value within the range of 0.1 to 0.6, it can be ensured that the first anti-rotation structure formed by the cooperation of the first protrusion 331 and the first groove 131 has a better anti-rotation effect, thereby improving the relative stability between the pole assembly and the cover plate 1, and it can also be ensured that the first protrusion 331 has a reasonable size, thereby ensuring that the limiting wall 121 is smoothly formed, thereby ensuring that the limiting portion 120 has a higher forming yield and saving costs.

[0096] It should be noted that the first groove portion 131 corresponds to the first protrusion portion 331. The larger the size of the first protrusion portion 331 along the wall thickness direction of the first side portion 302, the deeper the groove depth of the first groove portion 131, and the smaller the wall thickness of the remaining portion of the limiting wall 121 corresponding to the first groove portion 131 along the first direction.

[0097] In one embodiment, the dimension H1 of the first protrusion 331 protruding from the outer circumference of the first side portion 302 along the wall thickness direction of the first side portion 302 is in the range of 0.15 mm ≤ H1 ≤ 2 mm. This ensures that the first protrusion 331 has sufficient thickness, thereby ensuring that the first anti-rotation structure formed by the first protrusion 331 and the first groove 131 has a good anti-rotation effect, and also prevents the formation of the limiting wall 121 from being affected by excessive thickness of the first protrusion 331 and excessive depth of the first groove 131, thereby ensuring the formation yield of the limiting portion 120 and reducing production costs.

[0098] In one embodiment, the wall thickness H0 of the first side portion 302 is in the range of 0.6 mm ≤ H0 ≤ 3.5 mm. This ensures that the first side portion 302 of the upper plastic part 3 has sufficient thickness, thereby ensuring the structural strength of the first side portion 302 , while also preventing excessive material consumption due to excessive wall thickness of the first side portion 302 , thereby controlling weight and cost.

[0099] Cells were assembled using upper plastic parts 3 with different H1 / H0 ratios and subjected to torque testing to verify the impact of different H1 / H0 values on cell performance. The results are shown in Table 4. The torque test specifically involved assembling the pole assembly, consisting of pole 2 and upper plastic part 3, with the cover plate 1 to create the finished cover plate structure. A torque of 6 N·m was applied to the pole assembly for 30 seconds, and then the pole assembly was tested for airtightness. The torque test passed if no air leaks were detected.

[0100] Table 4 Effects of different H1 / H0 values on cell performance

[0101]

[0102] It can be seen from Table 4 that for the battery cells of Implementation Cases 31 to Implementation Cases 45, the values of H1 / H0 are all within the range of 0.1 to 0.6 specified in this application, and the torque test is OK; for the battery cell of Comparative Case 9, H1 / H0 is 0.067, which is less than 0.1 and is not within the range specified in this application. The anti-rotation effect of the anti-rotation structure formed by the cooperation between the first protrusion 331 and the first groove portion 131 is poor, and the battery cell torque test is NG; for the battery cell of Comparative Case 10, H1 / H0 is 0.8, which is greater than 0.6 and is not within the range specified in this application. Although the torque test is OK, since the first protrusion 331 is too thick and the corresponding groove depth of the first groove portion 131 is too large, the wall thickness of the remaining part of the limiting wall 121 corresponding to the first groove portion 131 is thin, the molding yield is poor, and it is not recommended for use. In summary, by setting H1 / H0 to a value within the range of 0.1 to 0.6, it can be ensured that the anti-rotation structure formed by the cooperation of the first protrusion 331 and the first groove 131 has a better anti-rotation effect, thereby improving the relative stability between the pole assembly and the cover plate 1, and it can also be ensured that the first protrusion 331 has a reasonable size, thereby ensuring that the limiting wall 121 is smoothly formed.

[0103] In one embodiment, further combined Figure 18As shown, the second protrusion 332 has a vertical dimension H2, where 0.2 mm ≤ H2 ≤ 2 mm. It should be noted that the second protrusion 332 corresponds to the second groove 132 on the flange 122. The larger the vertical dimension H2 of the second protrusion 332, the deeper the vertical groove 132 is. Correspondingly, the thickness of the remaining solid portion of the flange 122 corresponding to the second groove 132 is smaller. If H2 is less than 0.2mm, the thickness of the second protrusion 332 along the up-down direction is too small, and correspondingly, the groove depth of the second groove 132 along the up-down direction is too small. The anti-rotation effect of the second anti-rotation structure composed of the second protrusion 332 and the second groove 132 is poor, and relative rotation may occur between the first ring 301 and the flange 122. The stability between the pole assembly and the cover plate 1 is poor, and the battery cell performance is poor; if H2 is greater than 2mm, the thickness of the second protrusion 332 along the up-down direction is too large, and correspondingly, the groove depth of the second groove 132 along the up-down direction is too deep, the thickness of the remaining solid part of the flange 122 corresponding to the second groove 132 in the up-down direction is too small, and the molding yield is poor.

[0104] Therefore, by setting the dimension H2 of the second protrusion 332 in the up and down direction to be in the range of 0.2mm to 2mm, it can be ensured that the second anti-rotation structure formed by the cooperation of the second protrusion 332 and the second groove 132 has a better anti-rotation effect, thereby improving the relative stability between the pole assembly and the cover plate 1, and it can also be ensured that the second protrusion 332 and the second groove 132 have reasonable sizes, ensuring that the flange 122 is smoothly formed, thereby ensuring that the limiting portion 120 has a higher forming yield and saving production costs.

[0105] In one embodiment, there is one limit block 330, and one limit groove 130 corresponding to the limit block 330. The limit block 330 and the limit groove 130 are both one, and the limit groove 130 cooperates with the limit block 330 to form a rotation-stopping structure, which has a simple structure, is easy to process, and has low cost.

[0106] In other embodiments, there are multiple limit blocks 330, and the number of limit slots 130 is equal to and corresponds one-to-one with the multiple limit blocks 330. By providing multiple limit blocks 330 and multiple limit slots 130, and forming multiple anti-rotation structures with a one-to-one correspondence between the multiple limit slots 130 and the multiple limit blocks 330, the anti-rotation effect can be further enhanced, improving the relative stability between the pole assembly and the cover plate 1. The multiple limit blocks 330 are spaced apart circumferentially around the upper plastic part 3, and the multiple limit slots 130 are spaced apart circumferentially around the limit wall 121.

[0107] Preferably, the number of the limit blocks 330 and the limit slots 130 are both two, which can not only enhance the anti-rotation effect, but also ensure a simple structure and control production costs. It should be noted that the pole assembly includes a positive pole assembly and a negative pole assembly. When the number of the limit blocks 330 and the limit slots 130 are both two, the angles between the two limit blocks 330 on the positive pole assembly and the negative pole assembly are different. Optionally, as Figures 17 to 20 As shown, the angle between the two limit blocks 330 on the upper plastic part 3 of the negative column assembly is 180°. Figures 10 to 16 As shown, the angle between the two limit blocks 330 on the positive electrode column assembly is not 180°, so that the setting forms of the positive electrode column assembly and the negative electrode column assembly are different, which is convenient for distinguishing the positive and negative poles and preventing the positive and negative poles from being installed reversely during the transfer of the electrode assembly and the cover plate 1. The angle between the two limit blocks 330 refers to the central angle corresponding to the two limit blocks 330.

[0108] It can be understood that when the number of the limiting blocks 330 is greater than two, the multiple limiting blocks 330 are evenly spaced around the circumference of the upper plastic part 3 , and the multiple limiting grooves 130 are evenly spaced around the circumference of the limiting wall 121 .

[0109] In one embodiment, the pole 2 further includes a first column section 220, which is connected to the upper end of the main section 210 and has a diameter smaller than that of the main section 210. The upper plastic part 3 further includes a second side portion 320, which is connected to the inner ring of the first ring portion 301 and is located between the outer peripheral wall of the first column section 220 and the inner peripheral wall of the flange 122. The upper end refers to Figures 2 to 5 and Figure 14 The end in the direction of "up" indicated by the middle arrow; the first column segment 220 is cylindrical, and the outer peripheral wall of the first column segment 220 refers to the circumferential side of the cylinder; the flange 122 is annular, and the inner ring of the ring forms the second through hole 102, and the inner peripheral wall of the flange 122 refers to the side wall of the flange 122 facing the second through hole 102, and the first column segment 220 passes through the second through hole 102. By providing the pole 2 with a first column section 220 connected to the upper end of the main section 210, and the diameter of the first column section 220 is smaller than the diameter of the main section 210, the main section 210 is limited below the flange 122, and the first column section 220 can pass through the second through hole 102 surrounded by the inner ring of the flange 122, thereby facilitating the connection of the pole 2 with structural parts such as the busbar outside the battery cell. At the same time, by providing the upper plastic part 3 with a second side portion 320 connected to the inner ring of the first ring portion 301, the second side portion 320 is extended upward by the inner ring edge of the first ring portion 301 and is located between the first column section 220 and the flange 122, thereby enhancing the insulation between the pole 2 and the cover plate 1.

[0110] In one embodiment, a first rotation stop 211 is configured on the outer circumference of the main body section 210, and a second rotation stop 304 is configured on the inner circumference of the first side section 302. The first rotation stop 211 engages with the second rotation stop 304. The outer circumference of the main body section 210 refers to the circumferential side surface of the main body section 210 facing the limiting wall 121; the inner circumference of the first side section 302 refers to the circumferential inner wall of the first side section 302 facing the centerline thereof. The outer circumference of the main body section 210 and the inner circumference of the first side section 302 are disposed opposite each other. By constructing a first stop portion 211 on the outer peripheral side of the main section 210 and a second stop portion 304 corresponding to the first stop portion 211 on the inner peripheral side of the first side portion 302, the first stop portion 211 and the second stop portion 304 are snap-fitted together to form a third stop structure, thereby avoiding relative rotation between the pole 2 and the upper plastic part 3, thereby achieving relative fixation between the pole 2 and the upper plastic part 3, improving the stability of the pole assembly, and the pole assembly is assembled with the cover plate 1 as a whole, which is convenient for operation and improves assembly efficiency.

[0111] In one embodiment, the first anti-rotation portion 211 is a rotation-stop groove, which is formed by a portion of the outer circumference of the main body section 210 being recessed toward the centerline of the main body section 210. The second anti-rotation portion 304 is a rotation-stop block, which is formed by a portion of the inner circumference of the first side portion 302 being protruded toward the centerline of the first side portion 302. The rotation-stop block is engaged with the rotation-stop groove. It is understood that as an alternative embodiment, the first anti-rotation portion 211 can also be provided as a rotation-stop block, and the second anti-rotation portion 304 can also be provided as a rotation-stop groove, and the engagement between the rotation-stop block and the rotation-stop groove can also be achieved.

[0112] Optionally, the number of the first anti-rotation parts 211 is one or more, and the number of the second anti-rotation parts 304 is equal to and corresponds to the number of the first anti-rotation parts 211 .

[0113] Preferably, the number of the first rotation-stopping parts 211 and the second rotation-stopping parts 304 are both two, which can not only enhance the rotation-stopping effect, but also ensure a simple structure and control production costs. In this case, the angles between the two first rotation-stopping parts 211 on the positive and negative poles can be set to be different. Optionally, the angle between the two first rotation-stopping parts 211 on the negative pole is 180°, and the angle between the two first rotation-stopping parts 211 on the positive pole is not 180°, so that the positive pole and the negative pole are set in different forms, which is convenient for distinguishing the positive and negative poles and preventing reverse installation.

[0114] Optionally, the upper plastic part 3 is injection molded on the pole 2, that is, the pole 2 and the upper plastic part 3 are integrally injection molded to form a pole assembly, which is convenient to process and has a good fit between the pole 2 and the upper plastic part 3. It is understood that as an alternative embodiment, the upper plastic part 3 can also be injection molded separately first, and then the upper plastic part 3 and the pole 2 are assembled to form a pole assembly.

[0115] In one embodiment, the pole 2 also includes a second column segment 230, which is connected to the lower end of the main body segment 210 and is coaxially arranged with the main body segment 210. The second column segment 230 is passed through the first through hole 101, and the lower surface of the second column segment 230 is used to connect with the pole ear of the pole group in the battery cell.

[0116] It should be noted that the lower end of the plastic body 310 is lower than the lower end of the main section 210, that is, the second end surface 312 is located below the lower surface of the main section 210, so that the lower surface of the main section 210 is spaced from the upper surface of the pole area 110 to avoid direct contact between the pole 2 and the cover 1 and a short circuit. Figures 2 to 5 The end of the direction of "down" pointed by the middle arrow, the bottom refers to Figures 2 to 5 The arrow in the middle points to the direction of "down", and the lower surface refers to the direction along Figures 2 to 5 The surface in the direction of "down" indicated by the middle arrow.

[0117] In one embodiment, the cover structure further includes a sealing ring 4, which is sleeved on the second column segment 230, and the upper end of the sealing ring 4 is in contact with the lower surface of the main body segment 210. The sealing ring 4 is pressed between the pole 2 and the pole area 110 to insulate and seal the outer peripheral wall of the second column segment 230 and the hole wall of the first through hole 101, and the lower surface of the main body segment 210 and the upper surface of the pole area 110, and plays a supporting role for the main body segment 210.

[0118] In one embodiment, the pole 2 further includes a boss 240, which is connected to the upper end of the first column segment 220, and the diameter of the boss 240 is smaller than the diameter of the first column segment 220. The upper end of the first column segment 220 is flush with the upper end surface of the second side portion 320 of the upper plastic part 3, and the boss 240 is higher than the upper end surface of the second side portion 320, so that the pole 2 can be welded to the busbar through the boss.

[0119] In one embodiment, a positioning hole 241 is formed on the upper surface of the boss 240 to facilitate positioning of the busbar and the pole 2 during welding, thereby improving welding efficiency.

[0120] In one embodiment, further combined Figure 3 and Figure 14 As shown, the lower end of the plastic body 310 is lower than the lower surface of the main section 210, and the distance between the lower surface of the main section 210 and the lower end of the plastic body 310 in the vertical direction is L2, where 0.5mm≤L2≤2mm. Figure 3 and Figure 14 The surface in the “downward” direction indicated by the middle arrow, i.e., the lower end of the plastic component body 310 is the second end surface 312 .

[0121] By setting the lower end of the plastic body 310 below the lower surface of the main section 210, a gap is formed between the second end face 312 of the plastic body 310 for contacting the pole area 110 and the lower surface of the main section 210, so that the lower surface of the main section 210 and the upper surface of the pole area 110 are spaced apart. The formed gap is used to place the sealing ring 4. If L2 is less than 0.5mm, the distance between the main section 210 and the pole area 110 is too small, the compression amount of the sealing ring 4 is too large, and the life of the sealing ring 4 is reduced after being compressed. If L2 is greater than 2mm, the main section 210 and the pole area are too close. The spacing between the areas 110 is too large, the compression of the sealing ring 4 is insufficient, the sealing performance is poor, and the material used in the upper plastic part 3 increases, the cost increases, and the overall height design of the pole assembly is affected, which is not conducive to improving the volume energy density of the battery. Therefore, by setting the distance L2 between the lower surface of the main section 210 and the lower end of the plastic part main body 310 in the vertical direction to be in the range of 0.5mm to 2mm, it is ensured that the sealing ring 4 has a reasonable compression amount, which can not only ensure the sealing performance and the service life of the sealing ring 4, but also avoid the overall size of the pole assembly in the vertical direction being too large, saving costs and improving the volume energy density of the battery cell.

[0122] In one embodiment, Figures 4 and 5 As shown, the lower end of the upper plastic part 3 is further provided with a hook portion 303, which is bent from the lower end of the first side portion 302 toward the center line of the upper plastic part 3. The upper side of the hook portion 303 abuts against the lower surface of the main section 210 of the pole 2, further improving the supporting effect of the plastic part main body 310 on the pole 2 and improving the strength of the plastic part main body 310. It should be noted that Figures 1 to 3 In the illustrated cover structure, the upper plastic part 3 is not provided with the hook portion 303 .

[0123] According to an embodiment of the present invention, on the other hand, a battery cell is provided, including: a shell having an open end; a pole group arranged in the inner cavity of the shell; and the above-mentioned cover plate structure arranged at the open end of the shell.

[0124] 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 structure, characterized in that: include: The cover plate is constructed with a pole area and a limiting portion, wherein the pole area is formed by a portion of the upper surface of the cover plate being recessed downward, a first through hole is formed in the pole area, and the limiting portion includes a limiting wall and a flange, wherein the limiting wall is formed by extending upward from the circumferential edge of the pole area, and the flange is connected to the upper end of the limiting wall and is arranged opposite to the pole area; A pole assembly includes a pole and an upper plastic part, wherein the pole is arranged corresponding to the pole area, the upper plastic part is arranged between the pole and the cover plate and is fixed relative to the pole, the upper plastic part includes a plastic part body, the upper end of the plastic part body forms a first end face, the first end face abuts the lower surface of the flange, the lower end of the plastic part body abuts the upper surface of the pole area, and a plurality of first grooves are provided on the first end face. The projection area of the first end face on the upper surface of the pole area is S0, and the total projection area of the plurality of first grooves on the upper surface of the pole area is S1, wherein 0.15≤S1 / S0≤0.75, 50mm 2 ≤S0≤1000mm 2 .

2. The cover plate structure according to claim 1, characterized in that: The lower end of the plastic body forms a second end face, and a plurality of second grooves are formed on the second end face. The projection area of the second end face on the upper surface of the pole region is S2, and the total projection area of the plurality of second grooves on the upper surface of the pole region is S3, wherein 0.15≤S3 / S2≤0.7, 50mm 2 ≤S2≤1000mm 2 .

3. The cover plate structure according to claim 1, characterized in that: The pole includes a main body section, the diameter of the main body section is larger than the aperture of the first through hole, the plastic body includes a first ring portion and a first side portion, the first ring portion is located between the upper surface of the main body section and the lower surface of the flange, the upper surface of the first ring portion forms the first end face, the first side portion is connected to the outer ring of the first ring portion and is located between the outer circumferential surface of the main body section and the limiting wall, the total thickness dimension of the first ring portion along the up and down direction is L0, and the thickness of the entity part of the first ring portion corresponding to the first groove along the up and down direction is L1, wherein 0.4≤L1 / L0≤0.

95.

4. The cover plate structure according to claim 3, characterized in that: The total thickness dimension L0 of the first ring portion along the up-down direction has a value range of 0.5 mm ≤ L0 ≤ 1.5 mm.

5. The cover plate structure according to claim 3, characterized in that: A limiting groove is provided on the inner side of the limiting portion, and a limiting block is constructed on the outer side of the plastic component body, and the limiting block cooperates with the limiting groove.

6. The cover plate structure according to claim 5, characterized in that: The limiting groove includes a first groove portion opened on the inner side of the limiting wall and a second groove portion opened on the lower side of the flange, and the first groove portion is connected to the second groove portion; The limit block includes a first protrusion connected to the outer peripheral surface of the first side portion and a second protrusion connected to the first end surface, the first protrusion is connected to the second protrusion, the first protrusion cooperates with the first groove, and the second protrusion cooperates with the second groove.

7. The cover plate structure according to claim 6, characterized in that: The wall thickness of the first side portion is H0, and the dimension of the first protrusion protruding from the outer circumference of the first side portion along the wall thickness direction of the first side portion is H1, wherein 0.1≤H1 / H0≤0.6; and / or, a dimension H1 of the first protrusion protruding from the outer peripheral surface of the first side portion in a wall thickness direction of the first side portion is in the range of: 0.15 mm ≤ H1 ≤ 2 mm; And / or, a dimension of the second protrusion along the up-down direction is H2, wherein 0.2 mm ≤ H2 ≤ 2 mm.

8. The cover plate structure according to claim 5, characterized in that: The number of the limiting blocks is one or more, and the number of the limiting slots is equal to and corresponds to the number of the limiting blocks.

9. The cover plate structure according to any one of claims 3 to 8, characterized in that: The pole further includes a first column segment connected to the upper end of the main body segment and having a diameter smaller than that of the main body segment. The upper plastic part further includes a second side portion connected to the inner ring of the first ring portion and located between the outer peripheral wall of the first column segment and the inner peripheral wall of the flange. And / or, a first anti-rotation portion is configured on an outer circumference of the main body section, a second anti-rotation portion is configured on an inner circumference of the first side portion, and the first anti-rotation portion is engaged with the second anti-rotation portion; And / or, the lower end of the plastic body is lower than the lower surface of the main body section, and the distance between the lower surface of the main body section and the lower end of the plastic body in the up-down direction is L2, wherein 0.5 mm ≤ L2 ≤ 2 mm.

10. A battery cell, characterized in that: include: a housing having an open end; a pole group, disposed in the inner cavity of the shell; The cover plate structure according to any one of claims 1 to 9 is arranged at the open end of the shell.

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