Cover plate assembly and battery cell

Abstract

The invention relates to the technical field of batteries, and particularly discloses a cover plate assembly and a battery cell, the cover plate assembly comprises a cover plate body, a current collector and a connecting block, the cover plate body is provided with a first mounting hole, the connecting block is provided with a second mounting hole and a first sinking table, and the first sinking table comprises a first step surface and a second step surface; one end of the current collector sequentially penetrates through the first mounting hole and the second mounting hole from one side, deviating from the connecting block, of the cover plate body and then is riveted with the first step surface to form a convex part, and the convex part abuts against the second step surface to form a seam. The width B1 of the connecting block in the first direction is limited, and the distance W between the wall face of the side, deviating from the current collector, of the connecting block in the first direction and the adjacent side edge of the cover plate body is within the set range, so that it can be guaranteed that the flatness of the connecting block and the cover plate body is good after riveting, the connecting strength between the current collector and the connecting block is high, and separation is not prone to occurring; the cover plate assembly is safe and reliable. The invention further provides a battery cell which comprises the cover plate assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a cover plate assembly and an electric core. Background Art

[0002] Lithium-ion batteries are widely used in fields such as transportation power sources, power energy storage power sources, and new energy storage power sources due to their advantages of large capacity, high working voltage, strong charge retention ability, and long cycle life. A lithium-ion battery generally includes a plurality of electric cores, and each electric core is composed of a pole group, a cover plate body, a housing, etc. Among them, the cover plate body and the housing are fixed by welding and jointly form a sealed space for protecting the pole group. The cover plate body is integrated with functional areas such as a pole column, an explosion-proof valve, a liquid injection hole, etc. The tab of the pole group is welded to the current collector of the pole column to achieve electrical connection, thereby leading the current inside the electric core to the outside of the housing.

[0003] However, with the increasing demand for long endurance and fast charging of new energy vehicles, when designing the electric core, it is necessary to meet the large current overcurrent requirements such as 4C, 5C, 6C, etc. This requires that the pole column of the electric core has a sufficiently large overcurrent area. At the same time, in order to improve the space utilization rate of the whole lithium-ion battery pack, the electric core is gradually developing towards a "blade" structure, and the thickness of the electric core is gradually reduced, which results in limited installation space of the pole column on the cover plate body. How to maximize its overcurrent area while ensuring the mechanical strength of the cover plate body has become a key link in the design of the pole column. Summary of the Invention

[0004] The purpose of the present invention is to provide a cover plate assembly and an electric core, whose mechanical strength and structural strength are relatively high after the pole column is assembled with the cover plate body, can meet the assembly requirements, and at the same time, the overcurrent area of the pole column meets the needs of large current overcurrent and has excellent overcurrent capacity.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a cover plate assembly, including:

[0007] A cover plate body provided with a first mounting hole;

[0008] A pole column including a connecting block and a current collector. The connecting block is provided with a second mounting hole and a first counterbore. The second mounting hole is coaxial with the first counterbore. The first counterbore includes a first step surface and a second step surface. The first step surface is adjacent to the inner wall surface of the second mounting hole. One end of the current collector passes through the first mounting hole and the second mounting hole and is riveted to the first step surface to form a convex portion. The convex portion abuts against the second step surface and forms a joint;

[0009] In the first direction, the width of the cover plate body is A1, the width of the connecting block is B1, and the distance between the wall surface of the connecting block on the side away from the current collector and the adjacent side of the cover plate body is W;

[0010] Among them, the relationship among A1, B1, and W satisfies: A1 = B1 + 2W;

[0011] The value range of B1 is: 11mm ≤ B1 ≤ 20mm;

[0012] The value range of W is: 2mm ≤ W ≤ 6mm.

[0013] Optionally, in the first direction, the distance between the inner wall surface of the second mounting hole and the adjacent wall surface of the connecting block on the side away from the current collector is G, and the value range of G is: 1.6mm ≤ G ≤ 2mm.

[0014] Optionally, the current collector includes a plate body, a first column, and a second column connected in sequence. One end of the second column away from the plate body passes through the first mounting hole and the second mounting hole and is riveted to the first step surface to form the convex portion. The diameter of the second column is smaller than that of the first column, and a support table surface is formed between the circumferential side surface of the second column and the circumferential side surface of the first column. The support table surface is used to support the connecting block;

[0015] In the first direction, the width of the support table surface is h1, the width of the first step surface is h2, and the diameter of the first column is D, all in mm;

[0016] Among them, the relationship among h1, h2, D, G, and B1 satisfies: B1 = D - 2h1 + 2h2 + 2G;

[0017] The value range of h1 is: 0.6mm ≤ h1 ≤ 1.0mm;

[0018] The value range of h2 is: 0.3mm ≤ h2 ≤ 0.5mm.

[0019] Optionally, the calculation formula for D is:

[0020]

[0021] Among them, S is the current-carrying area of the first column, in mm 2 .

[0022] Optionally, the calculation formula for S is:

[0023]

[0024] Wherein, V is the capacity of the electrode group, with the unit of Ah; C is the charging rate of the electrode group, with the unit of A / Ah; P is the current-carrying capacity of the current collector, with the unit of A / mm 2 .

[0025] Optionally, there is an included angle β between the first stepped surface and the inner wall surface of the second mounting hole, and the value range of β is 80° ≤ β ≤ 90°.

[0026] Optionally, along the second direction, a second sunk platform is provided on the side of the connecting block facing away from the cover plate body. The second sunk platform includes a third stepped surface and a fourth stepped surface. The third stepped surface is adjacent to the second stepped surface. The convex part and the second stepped surface are welded at the joint to form a welded part, and the welded part is sunk in the second sunk platform;

[0027] Along the second direction, the dimension of the end of the welded part facing away from the cover plate body protruding from the third stepped surface is e, and the value range of e is: 0mm ≤ e < 0.2mm.

[0028] Optionally, along the first direction, the width of the third stepped surface is h3, and the fusion width of the welded part is w1; wherein, the relationship between w1 and h3 satisfies: 0.5 ≤ w1 / h3 ≤ 2.5;

[0029] The value range of w1 is: 0.5mm ≤ w ≤ 1.5mm;

[0030] The value range of h3 is: 0.6mm ≤ h3 ≤ 1.0mm.

[0031] Optionally, the cover plate assembly further includes a first plastic part, a second plastic part and a sealing part. The first plastic part is clamped between the connecting block and the cover plate body. The second plastic part is clamped between the current collector and the cover plate body. The sealing part is sleeved on the current collector.

[0032] On the other hand, the present invention provides an electric core, including a housing, an electrode group, and the cover plate assembly in any of the above solutions. The interior of the housing is hollow to form a receiving cavity and at least one end is provided with an opening. The electrode group is installed into the receiving cavity through the opening, and the cover plate assembly is connected to the end of the housing provided with the opening.

[0033] The beneficial effects of the present invention are:

[0034] The present invention provides a cover plate assembly, including a cover plate body and a pole, wherein the cover plate body is provided with a first mounting hole. The pole includes a current collector and a connecting block, wherein the connecting block is provided with a second mounting hole and a first sink, wherein the first sink includes a first step surface and a second step surface, wherein the first step surface is adjacent to the inner wall surface of the second mounting hole, and one end of the current collector passes through the first mounting hole and the second mounting hole in sequence from the side of the cover plate body away from the connecting block, and then is riveted with the first step surface to form a convex portion, wherein the convex portion abuts against the second step surface to form a seam. Thus, the current collector and the connecting block are fixedly mounted on the cover plate body by riveting. Along the first direction, the width of the connecting block is B1, and the distance between the wall surface of the connecting block away from the current collector and the adjacent side edge of the cover plate body is W, and the value range of B1 is: 11mm≤B1≤20mm, and the value range of W is: 2mm≤W≤6mm. By controlling the values ​​of B1 and W within the above-mentioned range, the size of the connecting block along the first direction can be reduced as much as possible while ensuring that the mechanical strength of the connecting block is high, so that the above-mentioned installation structure is suitable for use with some cover bodies with narrow widths, and after riveting, the connecting block and the cover body have good flatness, the connection strength between the pole and the cover body is high, separation is not easy to occur, and it is safe and reliable.

[0035] The present invention also provides a battery cell, comprising a shell, a pole group and a cover plate assembly. The pole group is installed in the accommodating cavity of the shell, and the cover plate assembly is connected to one end of the shell with an opening, and the pole group is encapsulated by the cover plate assembly and the shell. By adopting the above-mentioned cover plate assembly, the flatness of the cover plate body is good, ensuring that the cover plate body and the shell are well assembled, and the welding quality between the cover plate body and the shell is reliable and the sealing is good. At the same time, the pole integrated on the cover plate body can meet the overcurrent requirements of the pole group, is not prone to overheating, and has a high safety of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0037] Figure 1 An exploded view of a cover plate assembly provided in an embodiment of the present invention;

[0038] Figure 2 A top view of a cover plate assembly provided in an embodiment of the present invention;

[0039] Figure 3 for Figure 2 Sectional view of the AA section;

[0040] Figure 4is Figure 3 The partial enlarged view at position B in

[0041] Figure 5 The partial enlarged view when the current collector diagram and the connection block are riveted provided in the embodiment of the present invention;

[0042] Figure 6 The structural schematic diagram of the battery cell provided in the embodiment of the present invention.

[0043] In the figure:

[0044] 100, cover body; 101, first mounting hole;

[0045] 200, connection block; 201, second mounting hole; 2011, inner wall surface; 210, first sink; 2101, first step surface; 2102, second step surface; 220, second sink; 2201, third step surface; 2202, fourth step surface;

[0046] 300, current collector; 310, plate body; 320, first column; 3201, support table surface; 330, second column; 331, convex part; 332, welding part;

[0047] 400, first plastic part; 401, third mounting hole; 500, second plastic part; 501, fourth mounting hole; 600, seal; 700, housing; 701, opening; 800, electrode group; 810, tab. Specific embodiments

[0048] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the first feature has a lower horizontal height than the second feature.

[0050] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0052] As Figures 1 - 4 shown, this embodiment provides a cover plate assembly, which includes a cover plate body 100 and a terminal post, and the terminal post is integrally arranged on the cover plate body 100.

[0053] Specifically, the cover body 100 is provided with a first mounting hole 101. The pole includes a current collector 300 and a connection block 200, the connection block 200 is arranged on one side of the cover body 100, and the connection block 200 is provided with a second mounting hole 201 and a first sink 210, the second mounting hole 201 is coaxial with the first sink 210, the first sink 210 includes a first step surface 2101 and a second step surface 2102, the first step surface 2101 is adjacent to the inner wall surface 2011 of the second mounting hole 201, one end of the current collector 300 passes through the first mounting hole 101 and the second mounting hole 201 from the side of the cover body 100 away from the connection block 200, and then rivets with the first step surface 2101 to form a convex portion 331, and the convex portion 331 abuts against the second step surface 2102 to form a seam. Thus, the current collector 300 and the connection block 200 are fixedly mounted on the cover body 100 by riveting.

[0054] Along the first direction, the width of the connection block 200 is B1, and the distance between the wall of the connection block 200 facing away from the current collector 300 and the adjacent side of the cover body 100 is W. Figure 1 The Y-axis direction shown in . The value range of B1 is: 11mm≤B1≤20mm, for example, the value of B1 can be 11mm, 13mm, 15mm, 18mm or 20mm, etc. By controlling the value of B1 within the above value range, the size of the connection block 200 along the first direction can be minimized while ensuring the mechanical strength of the connection block 200 is high, so that the above installation structure is suitable for use with some cover bodies 100 with narrow widths.

[0055] The value range of W is: 2mm≤W≤6mm. For example, the value of W can be 2mm, 3mm, 4mm, 5mm or 6mm, etc. By controlling the value of W within the above value range, on the one hand, the riveting position of the current collector 300 and the connecting block 200 is far away from the side of the cover body 100 along the first direction, ensuring that the connecting block 200 and the cover body 100 have good flatness after riveting. On the other hand, the cover assembly also includes a first plastic part 400, which is sandwiched between the connecting block 200 and the cover body 100. By ensuring that the value of W is within the above range, sufficient installation space can be provided for the first plastic part 400. Optionally, the first plastic part 400 is made of PP or PE material and has good insulation properties.

[0056] Furthermore, along the first direction, the width of the cover body 100 is A1, and the relationship between A1, B1 and W satisfies: A1=B1+2W. By limiting the size setting of B1 and W, the width A1 of the cover body 100 along the first direction is small, and the mechanical strength and structural strength of the pole and the cover body 100 after assembly are high, which can meet the assembly requirements, and the flatness of the cover body 100 is better.

[0057] Continue to refer to Figure 3 and Figure 4 In this embodiment, along the first direction, the distance between the wall surface of the connecting block 200 facing away from the current collector 300 and the inner wall surface 2011 of the second mounting hole 201 is G, and the value range of G is: 1.6 mm ≤ G ≤ 2 mm. For example, the value of G can be 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, etc. By controlling the value of G within the above value range, on the one hand, it is ensured that the thickness of the connecting block 200 along the first direction is relatively thick, with high mechanical strength and structural strength, capable of resisting the stress during riveting with the current collector 300, not easily bulging and deforming, and the assembly of the current collector 300 and the connecting block 200 is good, with a high assembly yield rate; on the other hand, the riveting position of the current collector 300 and the connecting block 200 is far from the first plastic part 400, avoiding the deformation of the first plastic part 400 caused by the thermal influence during the welding of the tab 810 of the electrode group 800 and the current collector 300, and the structure of the cover plate assembly is intact.

[0058] Optionally, the current collector 300 in this embodiment includes a plate body 310, a first column 320, and a second column 330 connected in sequence, and the second column 330 is coaxial with the first column 320. Wherein, one end of the second column 330 facing away from the plate body 310 passes through the first mounting hole 101, the third mounting hole 401 of the first plastic part 400, and the second mounting hole 201 and is riveted to the first step surface 2101. The material at one end of the second column 330 facing away from the plate body 310 undergoes flow deformation, and a convex portion 331 is formed by bulging of the second column 330 at one end facing away from the plate body 310. The convex portion 331 and the second step surface 2102 of the first sunken platform 210 are combined to form a joint. Further, the diameter of the second column 330 is smaller than the diameter of the first column 320, and a support table surface 3201 is formed by the transition between the circumferential side surface of the second column 330 and the circumferential side surface of the first column 320. The support table surface 3201 can support the end surface of the connecting block 200 facing the cover plate body 100, so as to ensure that when the current collector 300 and the connecting block 200 are riveted, the riveting position of the connecting block 200 (at the first sunken platform 210) is not easily deformed, and the riveting yield rate is high.

[0059] Along the first direction, the width of the support table surface 3201 where the circumferential side surface of the second cylinder 330 transitions to the circumferential side surface of the first cylinder 320 is h1, and the value range of h1 is: 0.6 mm ≤ h1 ≤ 1.0 mm. For example, the value of h1 can be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, etc. By controlling the value of h1 within the above value range, it is ensured that the support table surface 3201 can provide good support for the connecting block 200. Otherwise, when the value of h1 is small, the support effect of the support table surface 3201 on the connecting block 200 is poor. When the second cylinder 330 is riveted to the first sinking platform 210 of the connecting block 200, the connecting block 200 is prone to deformation and the assembly yield is low. Of course, the value of h1 is not the larger the better. When the value of h1 is too large, the diameter difference between the first cylinder 320 and the second cylinder 330 is large, the diameter of the second cylinder 330 is small, the mechanical strength of the current collector 300 decreases, and it is easy to break at the second cylinder 330, resulting in poor reliability.

[0060] Further, the width of the first step surface 2101 of the first sinking platform 210 of the connecting block 200 is h2, and the value range of h2 is: 0.3 mm ≤ h2 ≤ 0.5 mm. For example, the value of h2 can be 0.3 mm, 0.4 mm, 0.5 mm, etc. By controlling the value of h2 within the above value range, it is ensured that the connection strength between the convex portion 331 formed after the second cylinder 330 expands in material and the first sinking platform 210 is relatively high. The support table surface 3201 and the convex portion 331 can clamp the connecting block 200, and it is not easy for the current collector 300 and the connecting block 200 to separate. The installation of the pole column on the cover plate body 100 is firm and reliable. Otherwise, when the value of h2 is small, the dimension of the convex portion 331 along the first direction is small, the riveting strength between the current collector 300 and the connecting block 200 is small, and it is easy to become loose, resulting in poor reliability. Refer to Figure 5 , when the value of h2 is too large, it will cause insufficient material when the second cylinder 330 expands in its radial direction (the first direction). There is a gap between the circumferential side wall of the convex portion 331 and the second step surface 2102, which affects the fitting of the circumferential side wall of the convex portion 331 and the second step surface 2102 of the connecting block 200, resulting in a decrease in connection strength and poor reliability.

[0061] Optionally, continue to refer to Figure 3 and Figure 4, there is an included angle β between the first stepped surface 2101 of the connecting block 200 and the inner wall surface 2011 of the second mounting hole 201, and the value range of β is 80° ≤ β ≤ 90°. For example, the value of β can be 80°, 85°, 87°, 90°, etc. By ensuring that the value of β is not greater than 90°, the connection strength between the convex portion 331 of the current collector 300 and the first sunk platform 210 of the connecting block 200 is relatively high, and the wall surface of the convex portion 331 facing the first stepped surface 2101 can tightly press the connecting block 200 to prevent the connecting block 200 from separating from the current collector 300 after being stressed, resulting in the pole column falling off from the cover plate body 100.

[0062] In this embodiment, the diameter of the first column body 320 of the current collector 300 is D, and the unit is mm. The value of D is mainly calculated based on the capacity of the electrode group 800, the charging rate, and the current-carrying capacity of the material of the current collector 300, so as to ensure that the current-carrying area of the pole column meets the requirement of large-current passing and has a relatively good current-carrying capacity. The relationship between h1, h2, D, G, and B1 satisfies: B1 = D - 2h1 + 2h2 + 2G, ensuring that the width of the pole column in the first direction will not be too large.

[0063] In an optional embodiment, the calculation formula of D is:

[0064]

[0065] wherein, S is the current-carrying area of the first column body 320, and the unit is mm 2 .

[0066] The calculation formula of S is:

[0067]

[0068] wherein, V is the capacity of the electrode group 800, and the unit is Ah. C is the charging rate of the electrode group 800, and the unit is A / Ah. The meaning of the charging rate is: the current value required for the battery cell to be charged to its capacity V within a specified time. The unit of capacity V is Ah, and the unit of the current value is A. P is the current-carrying capacity of the current collector 300, and the unit is A / mm 2 . The current-carrying capacity of the current collector 300 is related to the material of the current collector 300. When the pole column is a negative pole column, the current collector 300 is generally made of copper, and the value range of P is 8A / mm 2 ≤ P ≤ 12A / mm 2 . When the pole column is a positive pole column, the current collector 300 is generally made of aluminum, and the value range of P is 5A / mm 2 ≤ P ≤ 8A / mm 2 .

[0069] Through the above calculation formulas of D and S, the diameter design dimension that the first column 320 of the current collector 300 should satisfy can be obtained based on the relevant information of the electrode group 800 and the electrode post, so as to meet the overcurrent requirement. It should be noted that since the overcurrent capacity of copper is better than that of aluminum, when the sizes of the positive electrode post and the negative electrode post of the battery cell are designed to be the same, the negative electrode post can be designed according to the diameter design dimension of the first column 320 of the positive electrode post. Of course, in some better design schemes, the value of D can be further determined in combination with the simulation analysis results, and at the same time, the value of D can be optimized and adjusted with reference to the temperature rise data of the measured current collector 300, so as to further ensure that the size design of the current collector 300 is reasonable, the overcurrent area of its first column 320 meets the overcurrent requirement of large current, and the overcurrent capacity is better.

[0070] In addition, by utilizing the fluidity of the material of the current collector 300 itself, after the current collector 300 bulges due to stamping and the convex part 331 is joined with the second step surface 2102 of the first sinking platform 210 of the connecting block 200, the joint of the convex part 331 and the second step surface 2102 can be welded by laser to strengthen the fixing strength between the connecting block 200 and the current collector 300, ensuring that the electrode post is firmly and reliably installed on the cover body 100 and is not easy to fall off. Since the current collector 300 and the connecting block 200 jointly form the electrode post for leading out the current of the electrode group 800 through riveting and welding, the position of the first column 320 of the current collector 300 is the position with the smallest cross-sectional area in the whole electrode post, that is, the smallest overcurrent area. When the smallest overcurrent area can meet the overcurrent requirement of the current, the whole electrode post can meet the overcurrent requirement of the battery cell and is relatively safe and reliable, and is not easy to have the risk of overheating.

[0071] Continue to refer to Figure 3 and Figure 4 , along the second direction, on the side of the connecting block 200 away from the cover body 100, there is a second sinking platform 220, and the second sinking platform 220 is coaxial with the first sinking platform 210. The second sinking platform 220 includes a third step surface 2201 and a fourth step surface 2202. The third step surface 2201 is adjacent to the second step surface 2102. The convex part 331 and the second step surface 2102 are welded at the joint to form a welded part 332. The welded part 332 is sunk in the second sinking platform 220, that is, the end of the welded part 332 away from the cover body 100 does not protrude from the end surface of the connecting block 200 away from the cover body 100, thereby playing a certain protective role for the welded part 332 and preventing the welded part 332 from being knocked, which affects the sealing performance of the welded part 332.

[0072] Optionally, along the second direction, the end of the welding portion 332 on the side away from the cover body 100 protrudes from the third step surface 2201 by a dimension e, and the value range of e is: 0mm≤e<0.2mm. For example, the value of e can be 0mm, 0.1mm or 0.2mm, etc. By limiting the value of e within the above range, it can be ensured that the height difference between the end of the welding portion 332 on the side away from the cover body 100 and the third step surface 2201 along the second direction is small, and the welding portion 332 is prevented from protruding from the end surface of the connecting block 200 on the side away from the cover body 100, the appearance is good, and the flatness between the third step surface 2201 and the protrusion 331 of the current collector 300 meets the requirements. Among them, the second direction refers to Figure 3 The Z-axis direction shown in .

[0073] Furthermore, along the first direction, the width of the third step surface 2201 is h3, the weld width of the welding portion 332 is w1, and the relationship between w1 and h3 satisfies: 0.5≤w1 / h3≤2.5. For example, the value of w1 / h3 can be 0.5, 0.8, 1.0, 1.5, 2.0 or 2.5, etc. Through the above-mentioned size limitation, it is ensured that the welding portion 332 is completely located below the second sink 220, and the welding portion 332 is prevented from spreading along the first direction to the fourth step surface 2202 of the second sink 220, affecting the structural strength of the connecting block 200 and the welding strength of the welding portion 332. Welding problems such as pinholes and explosion points may occur at the welding portion 332, the weld appearance is poor, and the surface flatness of the connecting block 200 and the collector 300 on the side away from the cover body 100 is poor.

[0074] Optionally, the value range of w1 is: 0.5mm≤w1≤1.5mm, for example, the value of w1 can be 0.5mm, 0.6mm, 0.9mm, 1.0mm, 1.2mm or 1.5mm. By limiting the value of w1 within the above range, it can be ensured that the welding portion 332 can completely cover the joint between the protrusion 331 and the second step surface 2102, the welding strength is high, and the sealing is reliable. Otherwise, when the value of w1 is small, there may be a cold weld in the welding portion 332, resulting in a decrease in welding strength, affecting the sealing performance of the welding portion 332, and reducing the reliability of the battery. Of course, the value of w1 should not be too large. If the value of w1 is too large, it will affect the structural strength of the connecting block 200, and the reliability will be reduced when the battery cell is bumped.

[0075] The value range of h3 is: 0.6 mm ≤ h3 ≤ 1.0 mm. For example, the value of h3 can be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1.0 mm. By restricting the value of h3 within the above range, it can be ensured that the welded part 332 is completely located within the second sinking platform 220. Otherwise, when the value of h3 is small, the welded part 332 may spread along the first direction to the fourth step surface 2202 of the second sinking platform 220, affecting the structural strength of the connecting block 200, as well as the welding strength of the welded part 332, and the reliability and sealing performance of the welded part 332 will decrease.

[0076] Continue to refer to Figure 1 The cover plate assembly further includes a second plastic part 500 and a seal 600. The second plastic part 500 is clamped between the current collector 300 and the cover plate body 100. Optionally, the first plastic part 400 is made of PP or PE material and has good insulation performance. The seal 600 is sleeved on the first column 320 of the current collector 300. During installation, the current collector 300 sequentially passes through the fourth installation hole 501 of the second plastic part 500, the seal 600, the first installation hole 101 of the cover plate body 100, the third installation hole 401 of the first plastic part 400, and the second installation hole 201 of the connecting block 200 and then is assembled with the connecting block 200. Then, by using the fluidity of the material of the current collector 300 itself, the convex part 331 formed after the second column 330 of the current collector 300 is bulged by stamping is fitted with the second step surface 2102 of the first sinking platform 210 of the connecting block 200. Finally, the joint between the convex part 331 and the second step surface 2102 is welded and strengthened by laser welding.

[0077] This embodiment also provides a battery cell. Refer to Figure 6 This battery cell is a blade battery cell. The battery cell includes a housing 700, a pole group 800 and a cover plate assembly. The interior of the housing 700 is hollow to form a receiving cavity and openings 701 are provided at both ends along the second direction. The pole group 800 is installed into the receiving cavity through one of the openings 701. There are two cover plate assemblies. Each cover plate assembly is connected to one end of the housing 700 where the opening 701 is provided. The pole group 800 is encapsulated by the two cover plate assemblies and one housing 700. Both cover plate assemblies adopt the above assembly structure. Among the two cover plate assemblies, the pole column integrated on the cover plate body 100 of one cover plate assembly is the positive pole column, and the current collector 300 of the positive pole column is connected to the positive pole tab 810 of the pole group 800. The pole column integrated on the cover plate body 100 of the other cover plate assembly is the negative pole column, and the current collector 300 of the negative pole column is connected to the negative pole tab 810 of the pole group 800. The positive pole tab 810 and the negative pole tab 810 of the pole group 800 are arranged on the opposite sides of the pole group 800 along the second direction.

[0078] By adopting the above cover plate assembly, the flatness of the cover plate body 100 is good, ensuring good assembly of the cover plate body 100 and the housing 700. The welding quality between the cover plate body 100 and the housing 700 is reliable and the sealing performance is good. At the same time, the pole column integrated on the cover plate body 100 can meet the overcurrent requirement of the electrode group 800, is not prone to overheating problems, and the safety of the battery cell is relatively high.

[0079] Next, samples in some specific implementation cases are used to verify the value ranges of the above h1 and h2, to judge whether the cover plate assembly can be smoothly assembled when the values of h1 and h2 meet the above size limitations, and at the same time verify whether the pushing and pulling force F that the current collector 300 can withstand meets the assembly requirements (F > 1000N). For details, see Table 1.

[0080] The specific process of testing the pushing and pulling force F that the current collector 300 can withstand is as follows: Fix the cover plate body 100, apply a pushing or pulling force in the direction away from the cover plate body 100 or a pulling force in the direction towards the cover plate body 100 to the current collector 300. When F > 1000N, the current collector 300 will not come off the connecting block 200 or break, which indicates that the mechanical strength of the current collector 300 meets the requirements, and the connection strength between the current collector 300 and the connecting block 200 is relatively high, and the assembly of the battery cover plate assembly is good.

[0081] Table 1

[0082]

[0083] In Sample 1 and Sample 2, the value of h2 is less than the minimum value of 0.3mm ≤ h2 ≤ 0.5mm. The width of the first step surface 2101 in the connecting block 200 is relatively small, and the connection strength between the current collector 300 and the connecting block 200 after riveting is relatively low. When F ≤ 1000N, the current collector 300 and the connecting block 200 are separated, the installation of the pole column on the cover plate body 100 is not firm, the reliability is poor, and the assembly of the cover plate assembly is bad.

[0084] In Sample 3, Sample 4, and Sample 5, the values of h1 and h2 both meet their corresponding size limitations. After the current collector 300 and the connecting block 200 are riveted, the convex part 331 formed by the bulging of the second cylinder 330 of the current collector 300 can fit well with the first sinking platform 210 of the connecting block 200, and the flatness of the connecting block 200 and the cover plate body 100 is good. The connection strength between the current collector 300 and the connecting block 200 is relatively high. When F ≤ 1000N, the current collector 300 and the connecting block 200 are not prone to separation, the installation of the pole column on the cover plate body 100 is firm, the reliability is high, and the assembly of the cover plate assembly is good.

[0085] In Samples 6 and 7, the value of h2 is greater than the maximum value of 0.3 mm ≤ h2 ≤ 0.5 mm. The width of the first stepped surface 2101 in the connecting block 200 is relatively large. After the current collector 300 and the connecting block 200 are riveted, there is insufficient material for the swelling of the second cylinder 330 of the current collector 300. The convex portion 331 formed by the swelling of the second cylinder 330 cannot fit well with the second stepped surface 2102 of the first sunken platform 210, affecting the welding effect. The connection strength between the current collector 300 and the connecting block 200 is relatively low. When F ≤ 1000 N, the current collector 300 and the connecting block 200 are separated. The installation of the pole column on the cover plate body 100 is not firm, the reliability is poor, and the assembly of the cover plate assembly is defective.

[0086] In Samples 8 and 9, the value of h1 is less than the minimum value of 0.6 mm ≤ h1 ≤ 1.0 mm. The width of the supporting table surface 3201 in the current collector 300 is relatively small. The connection strength between the current collector 300 and the connecting block 200 after riveting is relatively low. When F ≤ 1000 N, the current collector 300 and the connecting block 200 are separated. The installation of the pole column on the cover plate body 100 is not firm, the reliability is poor, and the assembly of the cover plate assembly is defective.

[0087] In summary, when the values of h1 or h2 are on the small side, it will cause the limit value of the push-pull force F that the current collector 300 can withstand to decrease, and the fixing of the pole column on the cover plate body 100 is not firm. When h1 and h2 are on the large side, there will be a situation of insufficient swelling of the current collector 300 during riveting. There is a gap between the current collector 300 and the first sunken platform 210 of the connecting block 200, affecting the welding, resulting in a decrease in the limit value of the push-pull force F that the current collector 300 can withstand, and the fixing of the pole column on the cover plate body 100 is not firm.

[0088] Next, the following samples in some specific implementation solutions are used to verify the above-mentioned value range of h3, and judge whether the cover plate assembly can be smoothly assembled when the value of h3 meets the above-mentioned dimensional limitations, and whether the flatness of the connecting block 200 and the cover plate body 100 is good. For details, see Table 2.

[0089] Table 2

[0090]

[0091] In Samples 11 and 12, the value of h3 is less than the minimum value of 0.6 mm ≤ h3 ≤ 1.0 mm. The values of h1 and h2 both meet their corresponding dimensional limitations. The width of the third stepped surface 2201 in the connecting block 200 is relatively small. The appearance defect rate of the welded portion 332 formed after welding the convex portion 331 of the current collector 300 and the second stepped surface 2102 of the connecting block 200 is relatively high (the defect rate is between 3% - 4%), and the welding quality of the welded portion 332 is relatively poor, with pinholes and explosion points. The welding is unreliable, and it is easy to cause seal failure. The assembly of the cover plate assembly is defective.

[0092] In Samples 13 to 16, the values of h1, h2, and h3 all meet their respective dimensional limits. After the current collector 300 and the connecting block 200 are riveted, the convex portion 331 formed by the swelling of the second cylinder 330 of the current collector 300 can fit well with the first sunken platform 210 of the connecting block 200. The appearance of the welded portion 332 formed after welding the convex portion 331 of the current collector 300 to the second step surface 2102 of the connecting block 200 is good, without welding problems such as pinholes and explosion points. Moreover, the flatness of the connecting block 200 and the cover plate body 100 is relatively good, and the cover plate assembly is assembled well.

[0093] In Samples 17 and 18, the value of h3 is greater than the maximum value of 0.6 mm ≤ h3 ≤ 1.0 mm, and the values of h1 and h2 both meet their respective dimensional limits. Although the convex portion 331 formed by the swelling of the second cylinder 330 of the current collector 300 can fit well with the first sunken platform 210 of the connecting block 200, and the appearance of the welded portion 332 formed after welding the convex portion 331 of the current collector 300 to the second step surface 2102 of the connecting block 200 is good, without welding problems such as pinholes and explosion points, the opening dimension of the second sunken platform 220 on the connecting block 200 is relatively large, which affects the mechanical strength of the connecting block 200 itself. When the current collector 300 and the connecting block 200 are riveted, the connecting block 200 is prone to deformation, with poor flatness, and the cover plate assembly is poorly assembled.

[0094] In summary, it shows that the value of h3 is too small, and the welded portion 332 between the current collector 300 and the connecting block 200 is prone to appearance defects and welding quality problems. Of course, the value of h3 should not be too large either, otherwise the connecting block 200 is prone to deformation, and the assembly yield rate of the cover plate assembly is relatively low.

[0095] The following uses samples in some specific implementation cases to verify the above-mentioned value range of G, to judge whether the cover plate assembly can be successfully assembled when the value of G meets the above-mentioned dimensional limits, and at the same time verify whether the pushing and pulling force F that the current collector 300 can withstand meets the assembly requirements (F > 1000 N). For details, see Table 3.

[0096] Table 3

[0097]

[0098] In Samples 21 and 22, the value of G is less than the minimum value of 1.6 mm ≤ G ≤ 2 mm, and the values of h1, h2, and h3 all meet their respective dimensional limits. The thickness of the connecting block 200 is insufficient, and the mechanical strength of the connecting block 200 itself is relatively low, making it prone to deformation. The connection strength after the current collector 300 and the connecting block 200 are riveted is relatively low. When F ≤ 1000 N, the current collector 300 and the connecting block 200 are separated, the pole column is not firmly installed on the cover plate body 100, with poor reliability, and the cover plate assembly is poorly assembled.

[0099] Among Samples 23 to 27, the values of G, h1, h2, and h3 all meet their respective dimensional limits. The thickness of the connecting block 200 is sufficient, and the mechanical strength of the connecting block 200 itself is high, making it not prone to deformation. After the current collector 300 and the connecting block 200 are riveted, the connection strength between the current collector 300 and the connecting block 200 is high. When F ≤ 1000 N, the current collector 300 and the connecting block 200 will not separate, the pole post is firmly installed on the cover body 100, with high reliability, and the cover assembly is well assembled.

[0100] In summary, when the value of G meets the dimensional limit of 1.6 mm ≤ G ≤ 2 mm, the mechanical strength of the connecting block 200 itself can be ensured to be high. After the current collector 300 and the connecting block 200 are riveted, the connection strength between the current collector 300 and the connecting block 200 is high, the current collector 300 and the connecting block 200 are not easily separated, the pole post is firmly installed on the cover body 100, with high reliability, and the cover assembly is well assembled.

[0101] Next, the samples in some specific implementation schemes are used to verify the above-mentioned value range of W, to judge whether the cover assembly can be successfully assembled when the value of W meets the above-mentioned dimensional limit, and whether the flatness of the connecting block 200 and the cover body 100 is good. For details, see Table 4.

[0102] Table 4

[0103]

[0104] In Samples 31 and 32, the value of W is less than the minimum value of 2 mm ≤ W ≤ 6 mm. The values of h1, h2, h3, and G all meet their respective dimensional limits. The distance between the wall surface on the side of the connecting block 200 facing away from the current collector 300 and the adjacent side of the cover body 100 along the first direction is small, and the installation space of the first plastic part 400 is small. When the cover body 100 and the housing 700 are welded, the heat generated by the welding causes the first plastic part 400 to deform, and the defective rate is about 0.3%. The cover assembly is prone to seal failure and the battery cell assembly is poor.

[0105] Among Samples 33 to 36, the values of h1, h2, h3, G, and W all meet their respective dimensional limits. The distance between the wall surface on the side of the connecting block 200 facing away from the current collector 300 and the adjacent side of the cover body 100 along the first direction is large, and the installation space of the first plastic part 400 is sufficient. When the cover body 100 and the housing 700 are welded, the heat generated by the welding will not cause the first plastic part 400 to deform, the sealing performance of the cover assembly is reliable, and the battery cell assembly is good.

[0106] In summary, when the value of W meets the size limit of 2mm≤W≤6mm, the welding quality between the cover body 100 and the shell 700 can be guaranteed to be good. At the same time, the first plastic part 400 remains intact and will not be deformed by heat. The dimensional accuracy is high, the sealing performance of the cover assembly is reliable, the battery cell is well assembled, and the assembly yield is high.

[0107] The present invention reasonably limits the width h1 of the support table 3201 on the current collector 300 along the first direction, the width h2 of the first step surface 2101 on the connecting block 200, the width h3 of the third step surface 2201, the distance G between the inner wall surface 2011 of the second mounting hole 201 and the adjacent wall surface of the connecting block 200 away from the current collector 300, the width B1 of the connecting block 200, and the distance W between the wall surface of the connecting block 200 away from the current collector 300 and the adjacent side edge of the cover body 100. In this way, the diameter D of the current collector 300 can be maximized while ensuring that the width of the cover body 100 reaches the minimum value (ensuring that the space utilization rate of the entire battery pack is maximized), thereby ensuring that the flow area of ​​the pole meets the large current flow requirements of high-capacity and high-rate batteries, and the batteries are safe and reliable and not prone to overheating risks.

[0108] Obviously, the above embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A cover plate assembly, characterized in that: include: The cover body is provided with a first mounting hole; A pole, comprising a connection block and a current collector, wherein the connection block is provided with a second mounting hole and a first sink, the second mounting hole is coaxial with the first sink, the first sink comprises a first step surface and a second step surface, the first step surface is adjacent to the inner wall surface of the second mounting hole, one end of the current collector passes through the first mounting hole and the second mounting hole and is riveted to the first step surface to form a convex portion, the convex portion abuts against the second step surface to form a seam; Along the first direction, the width of the cover plate body is A1, the width of the connection block is B1, and the distance between the wall surface of the connection block facing away from the current collector and the adjacent side edge of the cover plate body is W; Among them, the relationship between A1, B1 and W satisfies: A1=B1+2W; The value range of B1 is: 11mm≤B1≤20mm; The value range of W is: 2mm≤W≤6mm.

2. The cover plate assembly according to claim 1, characterized in that: Along the first direction, the distance between the inner wall surface of the second mounting hole and the adjacent wall surface of the connecting block facing away from the current collector is G; The value range of G is: 1.6mm≤G≤2mm.

3. The cover plate assembly according to claim 2, characterized in that: The current collector comprises a plate body, a first column and a second column connected in sequence, one end of the second column away from the plate body passes through the first mounting hole and the second mounting hole and is riveted to the first step surface to form the convex portion, the diameter of the second column is smaller than the diameter of the first column, and a supporting table is formed between the peripheral side surface of the second column and the peripheral side surface of the first column, and the supporting table is used to support the connecting block; Along the first direction, the width of the support table is h1, the width of the first step surface is h2, and the diameter of the first column is D, all in mm; Among them, the relationship between h1, h2, D, G and B1 satisfies: B1 = D-2h1+2h2+2G; The value range of h1 is: 0.6mm≤h1≤1.0mm; The value range of h2 is: 0.3mm≤h2≤0.5mm.

4. The cover plate assembly according to claim 3, characterized in that: The calculation formula of D is: Wherein, S is the flow area of ​​the first column, in mm 2 .

5. The cover plate assembly according to claim 4, characterized in that: The calculation formula of S is: Wherein, V is the capacity of the electrode group, in Ah; C is the charge rate of the electrode group, in A / Ah; P is the flow capacity of the current collector, in A / mm 2 .

6. The cover plate assembly according to claim 1, characterized in that: An included angle β is formed between the first step surface and the inner wall surface of the second mounting hole, and a value range of β is 80°≤β≤90°.

7. The cover plate assembly according to claim 1, characterized in that: Along the second direction, a second sinking platform is provided on a side of the connection block away from the cover plate body, the second sinking platform includes a third step surface and a fourth step surface, the third step surface is adjacent to the second step surface, the convex portion and the second step surface are welded at the joint to form a welding portion, and the welding portion is sunk in the second sinking platform; Along the second direction, the end of the welding portion away from the cover plate body protrudes from the third step surface by a dimension e, and the value range of e is: 0mm≤e<0.2mm.

8. The cover plate assembly according to claim 7, characterized in that: Along the first direction, the width of the third step surface is h3, and the weld width of the welding portion is w1; Among them, the relationship between w1 and h3 satisfies: 0.5≤w1 / h3≤2.5; The value range of w1 is: 0.5mm≤w≤1.5mm; The value range of h3 is: 0.6mm≤h3≤1.0mm.

9. The cover plate assembly according to claim 1, characterized in that: The cover plate assembly further includes a first plastic part, a second plastic part and a sealing part. The first plastic part is sandwiched between the connection block and the cover plate body, the second plastic part is sandwiched between the current collector and the cover plate body, and the sealing part is sleeved on the current collector.

10. A battery cell, characterized in that: It comprises a shell, a pole group, and a cover plate assembly as described in any one of claims 1 to 9, wherein the shell is hollow inside to form a receiving cavity and has an opening at at least one end, the pole group is installed in the receiving cavity through the opening, and the cover plate assembly is connected to one end of the shell having the opening.

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