Pole structure, cover plate assembly and battery cell

Abstract

This invention relates to the field of battery technology, and discloses an electrode post structure, a cover plate assembly, and a battery cell. The electrode post structure includes: a base plate; a post connected to one side of the base plate along the Z direction, the post having a first axis extending along the Z direction; and a flange connected to the end of the post away from the base plate along the Z direction. The flange surrounds the circumferential edge of the post in the XY plane and extends along the Z direction. A groove is formed at the end of the flange near the post along the Z direction. The flange is adapted to fold parallel to the XY plane in a direction away from the first axis under external force. By providing a flange at the edge of the post away from the base plate and forming a groove at the root of the flange, the structural strength of the root of the flange is reduced by the groove, allowing the flange to fold smoothly. This avoids cracks and incomplete folding at the root of the flange after folding, ensuring the flatness of the electrode post after folding and thus guaranteeing a good folding effect.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to electrode structures, cover plate assemblies, and battery cells. Background Technology

[0002] The terminal post is a crucial component of the cover plate assembly in a battery cell. The cover plate assembly also includes a cover plate body, upper plastic, lower plastic, and sealing rings. The upper and lower plastics are located on opposite sides of the cover plate body along its height. The terminal post consists of a base plate and a post body. The base plate is located below the lower plastic, and the post body passes sequentially through the lower plastic, the cover plate body, and the upper plastic. During the cover plate assembly molding process, the upper structure of the terminal post is flanged by a punch and pressed onto the surface of the upper plastic, achieving a seal for the entire cover plate assembly and ensuring its structural strength. However, the flanged structure of the upper part of the terminal post is folded under the action of the punch die. Existing flanged structures suffer from problems such as difficulty in folding, poor folding effect (cracks at the root after folding, incomplete folding, and difficulty in ensuring the flatness of the terminal post after folding), which seriously affect the quality of the battery cell. Summary of the Invention

[0003] This invention provides a pole post structure, a cover plate assembly, and a battery cell to solve the problems of difficult folding and poor folding effect of the flange structure.

[0004] In a first aspect, the present invention provides a pole post structure, comprising: a base plate; a post body connected to one side of the base plate along the Z direction, the post body having a first axis extending along the Z direction; a flange portion connected to one end of the post body away from the base plate along the Z direction, the flange portion being arranged around the circumferential edge of the post body in the XY plane, and the flange portion extending along the Z direction before folding, the flange portion having a groove at one end of the post body along the Z direction, the flange portion being adapted to be folded along the direction away from the first axis to be parallel to the XY plane under the action of an external force.

[0005] Beneficial effects: By setting a flange at the edge of the column away from the base plate and opening a groove at the root of the flange, the structural strength of the root of the flange is reduced by the groove, so that the flange can be smoothly folded under the external force applied by the punch die. At the same time, the groove also provides material feeding space for the deformation of the flange during the folding process, avoiding cracks at the root of the flange after folding and avoiding uneven material feeding that would result in an incomplete folding of the flange. This helps to ensure that the upper surface of the flange is flush with the upper surface of the column after folding, ensuring the flatness of the pole post after folding, thus ensuring a good folding effect and improving the quality of the cover plate assembly and the battery cell.

[0006] In one optional embodiment, before the flange is folded, the height of the flange along the Z direction is H, and the groove height along the Z direction is h, wherein h and H satisfy the relationship: 0.2≤h / H≤0.5.

[0007] Beneficial effects: It can ensure that the flange can be folded smoothly and with a good folding effect, and can also avoid excessive damage to the structural strength of the flange by the groove, ensuring that the flange has sufficient structural strength, thereby preventing the flange from deforming during the use of the battery cell, and ensuring the airtightness of the cover assembly and the safety of the battery cell.

[0008] In one optional implementation, the value of H is in the range of 1.5 mm ≤ H ≤ 4 mm.

[0009] Beneficial effects: It can ensure the structural strength of the flange itself and the pressing effect of the flange on the first plastic part after folding, thereby ensuring the stability and airtightness of the cover plate assembly structure. It can also avoid material waste, thereby saving costs and improving the energy density of the battery cell.

[0010] In one optional embodiment, before the flange is folded, the inner and outer contours of the flange in the XY plane are equal in size to the outer contour of the column in the XY plane. The perimeter of the column in the XY plane is S, and the total arc length of the groove along the circumference of the column is S1. The relationship between S1 and S is: 0.33≤S1 / S≤0.67.

[0011] Beneficial effects: It can ensure that the flange can be folded smoothly and with a good folding effect, and can also avoid excessive damage to the structural strength of the flange by the groove, ensuring that the flange has sufficient structural strength, thereby preventing the flange from deforming during the use of the battery cell, and ensuring the airtightness of the cover assembly and the safety of the battery cell.

[0012] In one optional embodiment, the column is a cylinder with a diameter of D, wherein the value of D is in the range of 10 mm ≤ D ≤ 25 mm.

[0013] Beneficial effects: It can ensure that the column has sufficient structural strength, improve the reliability of the electrode, avoid material waste, thereby saving costs and improving the energy density of the battery cell.

[0014] In one alternative embodiment, the number of the grooves is multiple, and the multiple grooves are distributed circumferentially along the column in the XY plane.

[0015] Beneficial effects: By setting multiple grooves spaced apart along the circumference of the column, the structural strength of the root of the flange can be weakened evenly along the circumference of the column, further ensuring the smooth folding process of the flange. In addition, the way multiple grooves are spaced apart along the circumference of the column can avoid the excessive arc length of a single groove, thereby avoiding excessive damage to the local structural strength of the flange by a groove with an excessive arc length. On the basis of ensuring the smooth folding of the flange, the structural strength and structural stability of the flange can be guaranteed, thereby improving the reliability of the pole.

[0016] In one alternative embodiment, before the flange is folded over, the groove is a through groove that penetrates the flange radially along the column.

[0017] Beneficial effects: It is easy to process and can effectively reduce the difficulty of folding the edge.

[0018] In one optional embodiment, the thickness of the folded edge along the Z direction is T, wherein the value of T ranges from 0.5 mm to 2.5 mm.

[0019] Beneficial effects: It can ensure the structural strength of the flange itself, thereby ensuring the stability and airtightness of the cover plate assembly structure, and can also avoid material waste, thereby saving costs and improving the energy density of the battery cell.

[0020] Secondly, the present invention also provides a cover plate assembly, comprising: a cover plate body having an electrode post hole; and an electrode post formed by folding the aforementioned electrode post structure, wherein the post body passes through the electrode post hole. Since the cover plate assembly includes an electrode post structure and has the same effect as the electrode post structure, it will not be described in detail here.

[0021] Thirdly, the present invention also provides a battery cell, comprising: a housing having an open end; an electrode assembly disposed within the inner cavity of the housing; and the aforementioned cover plate assembly covering the open end of the housing. Since the battery cell includes the cover plate assembly and has the same effect as the cover plate assembly, it will not be described further here. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of a pole post structure according to an embodiment of the present invention; Figure 2 for Figure 1 A top view of the pole structure shown; Figure 3 for Figure 1 The front view of the pole structure shown; Figure 4 for Figure 1 A schematic diagram of the pole structure formed after the flange of the pole structure is folded over; Figure 5 for Figure 4 A top view of the pole shown; Figure 6 This is a schematic diagram of the structure of a cover plate assembly according to an embodiment of the present invention; Figure 7 for Figure 6 A structural schematic diagram of the cover plate assembly from the bottom view; Figure 8 for Figure 6 An exploded view of the cover plate assembly shown; Figure 9 for Figure 6 Top view of the cover plate assembly shown; Figure 10 for Figure 9 A cross-sectional view along the AA direction; Figure 11 for Figure 9 Cross-sectional view along the BB direction; Figure 12 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present invention; Figure 13 for Figure 12 The diagram shown is an exploded view of the battery cell.

[0024] Explanation of reference numerals in the attached figures: 1. Pole post; 11. Base plate; 12. Column body; 13. Flanged part; 131. Tank body; 2. Cover plate body; 21. Pole post hole; 22. Injection hole; 23. Pressure relief hole; 3. First plastic part; 4. Second plastic part; 5. Sealing ring; 6. Pressure relief valve; 7. Pressure relief valve patch; 8. Housing; 9. Pole assembly; 10. Adapter plate. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The terminal post is a crucial component of the cover plate assembly in a battery cell. The cover plate assembly also includes the cover plate body, upper plastic, lower plastic, and sealing rings. The upper and lower plastics are located on opposite sides of the cover plate body along its height. The terminal post consists of a base plate and a post body. The base plate is located below the lower plastic, and the post body passes sequentially through the lower plastic, the cover plate body, and the upper plastic. For cover plate assemblies using a flanged terminal post structure, during the cover plate assembly forming process, the upper structure of the terminal post is flanged by a punch and pressed onto the surface of the upper plastic, achieving a seal for the entire cover plate assembly and ensuring its structural strength. However, the flanged structure at the top of the terminal post is folded under the action of the punch die. The flanged structure itself has a certain structural strength, which hinders the smooth folding process. This results in problems such as difficulty in folding, poor folding effect (cracks at the root after folding, incomplete folding, and difficulty in ensuring the flatness of the terminal post after folding), seriously affecting the quality of the battery cell.

[0027] The following is combined Figures 1 to 13 The following describes embodiments of the present invention.

[0028] According to embodiments of the present invention, in one aspect, a pole post structure is provided, such as... Figures 1 to 3 As shown, the pole structure includes: a base plate 11, a column 12, and a flange 13. The column 12 is connected to one side of the base plate 11 along the Z direction, and the column 12 has a first axis extending along the Z direction. The flange 13 is connected to the end of the column 12 away from the base plate 11 along the Z direction. The flange 13 is arranged around the circumferential edge of the column 12 in the XY plane, and the flange 13 extends along the Z direction before folding. A groove 131 is opened at the end of the flange 13 near the column 12 along the Z direction. The flange 13 is adapted to be folded into a direction away from the first axis and parallel to the XY plane under the action of external force. The flange 13 is formed by the region of the circumferential edge of the column 12 extending along the Z direction away from the base plate 11. The groove 131 is opened at the root of the flange 13 (i.e., at the position where the flange 13 is connected to the column 12).

[0029] It should be noted that the pole structure has X, Y, and Z directions that intersect each other in pairs. Preferably, the X, Y, and Z directions are perpendicular to each other to form a rectangular coordinate system; the X and Y directions together form the XY plane. Here, the X, Y, and Z directions refer to... Figure 1 The directions indicated by the middle arrows are "X", "Y", and "Z". Specifically, the pole structure is installed on the cover plate body 2, with the X direction being the length direction of the cover plate body 2, the Y direction being the width direction of the cover plate body 2, and the Z direction being the thickness direction of the cover plate body 2.

[0030] By applying the pole post structure of this embodiment, a flange 13 is provided at the edge of the end of the pole 12 away from the base plate 11, and a groove 131 is opened at the root of the flange 13. The groove 131 reduces the structural strength of the root of the flange 13, so that the flange 13 can be smoothly folded under the external force applied by the punch die. At the same time, the groove 131 also provides material feeding space for the deformation of the flange 13 during the folding process, avoiding cracks at the root of the flange 13 after folding, and avoiding uneven material feeding that would cause the flange 13 to be folded incompletely. This helps to ensure that the upper surface of the flange 13 after folding is flush with the upper surface of the pole 12, ensuring the flatness of the pole 1 after folding, thereby ensuring a good folding effect and improving the quality of the cover plate assembly and the battery cell.

[0031] It should be noted that the flanged portion 13 has two states relative to the column 12: before and after folding. The flanged portion 13 before folding is as follows: Figures 1 to 3 As shown, the flanged portion 13 before folding extends along the Z direction; the flanged portion 13 after folding is as follows: Figures 4 to 5 As shown.

[0032] Specifically, during the assembly of the cover plate assembly, after the pole post structure is inserted into the pole post hole 21, the flange 13 is adapted to be folded from the root of the flange 13 under the action of external force, folding it to a position outside the outer periphery of the post body 12, so as to form a shape as shown in the figure. Figures 4 to 5 The pole post 1 shown has an upper surface of the folded-over flange 13 flush with the upper surface of the column 12. The inner peripheral wall of the flange 13 before folding forms the upper surface of the folded-over flange 13. The cover plate assembly also includes a first plastic part 3 disposed between the cover plate body 2 and the folded-over flange 13. The folded-over flange 13 is pressed onto the upper surface of the first plastic part 3, and the flange 13 and the first plastic part 3 are tightly fitted to ensure the insulation between the cover plate body 2 and the pole post 1. The upper surface mentioned refers to the upper surface along the Z direction, that is, the surface of the flange 13 / column 12 facing away from the base plate 11 along the Z direction.

[0033] It should be noted that, for the pole post structure, unless otherwise specified, the dimensional parameters mentioned in this embodiment are the dimensional parameters of the flange 13 before folding.

[0034] In one embodiment, further combination Figure 1 and Figure 3 As shown, before the flange 13 is folded, the height of the flange 13 along the Z direction is H, and the groove height of the groove 131 along the Z direction is h. The relationship between h and H is: 0.2 ≤ h / H ≤ 0.5, and the units of h and H are both mm. Specifically, H is the height of the flange 13 in the Z direction before folding, and h is the groove height of the groove 131 along the Z direction before folding.

[0035] If h / H is less than 0.2, the groove height of the groove 131 is too small relative to the height of the flange 13. The groove 131 has a limited effect on reducing the strength of the root of the flange 13, and the flange 13 still has the problem of difficulty in folding. After the flange 13 is folded, there may be poor folding effects such as incomplete folding structure, inability of the flange 13 to fit tightly with the first plastic part 3, and cracks at the root of the flange 13. It is difficult to ensure the flatness of the upper surface of the pole post 1 and the airtightness of the cover assembly. If h / H is greater than 0.5, the groove height of the groove 131 is too large relative to the height of the flange 13, which greatly damages the structural strength of the flange 13, resulting in low structural strength of the flange 13. When the pole post 1 is subjected to external force, the flange 13 is prone to deformation, the pole post 1 becomes loose, and thus affects the airtightness of the cover assembly.

[0036] Therefore, by limiting h / H to a value between 0.2 and 0.5, it is possible to ensure that the flange 13 can be folded smoothly and with a good folding effect, while avoiding excessive damage to the structural strength of the flange 13 by the groove 131. This ensures that the flange 13 has sufficient structural strength, thereby preventing deformation of the flange 13 during the use of the battery cell and ensuring the airtightness of the cover assembly and the safety of the battery cell.

[0037] Optionally, h / H can be any value from 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or a value between any two values.

[0038] In one embodiment, the value of H ranges from 1.5 mm to H ≤ 4 mm. Further combining... Figure 3 , Figure 5 and Figure 11 As shown, the folded flange 13 is annular. The ring width H1 of the folded flange 13 in the XY plane is equal to the height H in the Z direction of the folded edge of the flange 13. The electrode post 1 is pressed onto the first plastic part 3 through the folded flange 13. If H is less than 1.5 mm, the height of the flange 13 in the Z direction before folding is too small, that is, the ring width of the folded flange 13 in the XY plane is too small, resulting in insufficient pressing area for the first plastic part 3, making it difficult to ensure stability. The flange 13 is prone to warping under external force, which leads to insufficient airtightness of the cover assembly. If H is greater than 4 mm, the height of the flange 13 in the Z direction before folding is too large, that is, the ring width of the folded flange 13 in the XY plane is too large, resulting in design redundancy, wasted materials and costs, and increased weight of the electrode post 1, which is not conducive to improving the energy density of the battery cell.

[0039] Therefore, by limiting H to a value within the range of 1.5 mm to 4 mm, the structural strength of the flange 13 itself can be guaranteed, as well as the pressing effect of the flange 13 on the first plastic part 3 after folding, thereby ensuring the stability and airtightness of the cover plate assembly structure. At the same time, material waste can be avoided, thereby saving costs and improving the energy density of the battery cell.

[0040] Optionally, H can be any value among 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, and 4 mm, or a value between any two of these values.

[0041] In one embodiment, before the flange 13 is folded, the inner and outer contours of the flange 13 in the XY plane are equal in size to the outer contour of the column 12 in the XY plane. The perimeter of the column 12 in the XY plane is S, and the total arc length of the groove 131 along the circumference of the column 12 is S1. S1 and S satisfy the relationship: 0.33≤S1 / S≤0.67, where the units of S1 and S are both mm. It should be noted that the orthographic projection of the flange 13 along the Z direction onto the column 12 is annular, and the outer ring of the annular shape coincides with the outer perimeter of the column 12; S is the circumference of the column 12; the groove 131 is formed on the flange 13, and the orthographic projection of the flange 13 along the Z direction onto the upper surface of the column 12 is annular, so the orthographic projection of the groove 131 along the Z direction onto the upper surface of the column 12 is a segment of the annular shape, and the arc length of the groove 131 refers to the arc length of the groove 131 on the outer ring of the flange 13 before folding; the number of grooves 131 can be one or more, and S1 is the total arc length of all grooves 131 on the outer ring of the flange 13 before folding; specifically, when the number of grooves 131 is one, S1 is the arc length of one groove 131, and when the number of grooves 131 is multiple, S1 is the sum of the arc lengths of multiple grooves 131, where multiple refers to two or more.

[0042] It should be noted that if S1 / S is less than 0.33, the total arc length of the groove 131 is too small relative to the perimeter of the column 12, and the grooving size along the circumference of the column 12 is insufficient. Therefore, the groove 131 has a limited effect on reducing the strength of the root of the flange 13, and the flange 13 still faces difficulties in folding. After folding, the flange 13 may exhibit poor folding performance, such as an incomplete folded structure, inability to tightly fit the flange 13 with the first plastic part 3, and cracks appearing at the root of the flange 13. If the flatness of the upper surface of the pole post 1 and the airtightness of the cover plate assembly are not guaranteed, it will be difficult to ensure the flatness of the upper surface of the pole post 1 and the airtightness of the cover plate assembly. If S1 / S is greater than 0.67, the total arc length of the groove 131 is too large relative to the perimeter of the pole post 12, the grooving size along the circumference of the pole post 12 is too large, and the structural strength of the flange 13 is too low. When the pole post 1 is subjected to external force, the flange 13 is prone to deformation, the pole post 1 becomes loose, and thus the airtightness of the cover plate assembly is affected.

[0043] Therefore, by limiting the value of S1 / S to the range of 0.33 to 0.67, it is possible to ensure that the flange 13 can be folded smoothly and with a good folding effect, while avoiding excessive damage to the structural strength of the flange 13 by the groove 131. This ensures that the flange 13 has sufficient structural strength, thereby preventing deformation of the flange 13 during the use of the battery cell and ensuring the airtightness of the cover assembly and the safety of the battery cell.

[0044] Optionally, the value of S1 / S can be any one of 0.33, 0.333, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.667, or 0.67, or a value between any two values.

[0045] Preferably, the value of S1 / S ranges from 1 / 3 to 2 / 3.

[0046] In one embodiment, the column 12 is a cylinder with a diameter of D, where D ranges from 10 mm to 25 mm. The cylindrical structure is simple and easy to manufacture. Correspondingly, the flange 13 is cylindrical, and its orthographic projection along the Z-direction in the XY plane is an annulus. The circumference of the column 12 in the XY plane is S = π × D. If D is less than 10 mm, the diameter of the column 12 is too small, resulting in insufficient structural strength and poor reliability. If D is greater than 25 mm, the diameter of the column 12 is too large, leading to design redundancy, wasted materials and costs, and increased weight of the electrode post 1, which is detrimental to improving the energy density of the battery cell.

[0047] Therefore, by limiting D to a value within the range of 10 mm to 25 mm, it is possible to ensure that the column 12 has sufficient structural strength and improve the reliability of the pole 1, while also avoiding material waste, thereby saving costs and improving the energy density of the battery cell.

[0048] Optionally, the value of D can be any one of 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, or a value between any two of these values.

[0049] In one embodiment, there are multiple grooves 131, which are distributed circumferentially along the column 12 in the XY plane. By distributing multiple grooves 131 circumferentially along the column 12, the structural strength of the root of the flange 13 can be uniformly weakened by the multiple grooves 131 along the circumference of the column 12, further ensuring the smooth folding process of the flange 13. Moreover, the method of distributing multiple grooves 131 circumferentially along the column 12 can avoid the excessive arc length of a single groove 131, thereby avoiding excessive damage to the local structural strength of the flange 13 by a groove 131 with an excessive arc length. While ensuring the smooth folding of the flange 13, the structural strength and structural stability of the flange 13 can be guaranteed, thereby improving the reliability of the pole post 1.

[0050] Preferably, the multiple grooves 131 are evenly distributed along the circumference of the column 12, which further improves the uniformity of the distribution of the multiple grooves 131 along the circumference of the column 12.

[0051] Preferably, the number of tanks 131 is three. Of course, as an alternative implementation, the number of tanks 131 can also be two, four, five, etc.

[0052] In one embodiment, before the flange 13 is folded, the groove 131 is a through groove that penetrates the flange 13 radially along the column 12. It should be noted that the column 12 is a cylinder, and radial refers to the radial direction of the cylinder; the flange 13 is cylindrical, and the groove 131 penetrates the cylinder wall radially; further combined with... Figure 11 As shown, after the flange 13 is folded, the groove 131 penetrates the folded flange 13 along the Z direction. By setting the groove 131 as a through groove that penetrates the flange 13 radially along the column 12, it is easier to process and can effectively reduce the difficulty of folding the flange 13.

[0053] In other embodiments, the groove 131 may not penetrate the flange 13, but may be a groove provided on the inner or outer wall of the flange 13.

[0054] In one embodiment, further combination Figure 11As shown, the thickness of the folded flange 13 along the Z direction is T, where the value of T ranges from 0.5 mm to 2.5 mm. It should be noted that the thickness T of the folded flange 13 along the Z direction is the same as the wall thickness of the flange 13 before folding in the XY plane. If T is less than 0.5 mm, the thickness of the folded flange 13 is too small, resulting in poor structural strength. The flange 13 is prone to deformation under external forces, leading to poor stability and insufficient airtightness of the cover assembly after deformation. If T is greater than 2.5 mm, the thickness of the folded flange 13 is too large, resulting in design redundancy, wasted materials and costs, and increased weight of the electrode post 1, which is detrimental to improving the energy density of the battery cell. Therefore, by limiting T to a value within the range of 0.5 mm to 2.5 mm, the structural strength of the flange 13 itself can be guaranteed, thereby ensuring the stability and airtightness of the cover plate assembly structure. At the same time, material waste can be avoided, thus saving costs and improving the energy density of the battery cell.

[0055] Optionally, T can be any value among 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, and 2.5 mm, or a value between any two of these values.

[0056] According to an embodiment of the present invention, in another aspect, a cover plate assembly is also provided, such as... Figures 6 to 11 As shown, the cover plate assembly includes: a cover plate body 2 and a pole post 1. The cover plate body 2 has a pole post hole 21, which is a through hole extending out of the cover plate body 2 along the Z direction; the pole post 1 is formed by folding the above-mentioned pole post structure, and the post body 12 of the pole post 1 passes through the pole post hole 21.

[0057] In one embodiment, the cover plate assembly further includes a first plastic part 3 and a second plastic part 4. The first plastic part 3 is disposed between the cover plate body 2 and the folded flange portion 13. The folded flange portion 13 is pressed onto the first plastic part 3 to ensure the sealing and insulation between the cover plate body 2 and the pole post 1. The second plastic part 4 is disposed on the side of the cover plate body 2 away from the first plastic part 3 in the Z direction, specifically the side of the cover plate body 2 facing the inner cavity of the housing 8, to ensure the insulation between the cover plate body 2 and the pole group 9.

[0058] Specifically, the first plastic part 3 has a first mounting hole, and the second plastic part 4 has a second mounting hole. The post 12 passes through the first mounting hole, the pole hole 21, and the second mounting hole in sequence. The base plate 11 is disposed on the side of the second plastic part 4 away from the cover plate body 2 along the Z direction. The second plastic part 4 extends around the circumferential edge of the second mounting hole and between the cover plate body 2 and the base plate 11 to further ensure the insulation between the pole 1 and the cover plate body 2. Specifically, the first plastic part 3 is the upper plastic and the second plastic part 4 is the lower plastic.

[0059] In one embodiment, the cover plate body 2 is further provided with an injection hole 22, which extends through the cover plate body 2 in the Z direction for injecting electrolyte into the battery cell. When it is not necessary to inject electrolyte into the battery cell, the injection hole 22 is sealed by a sealing plug.

[0060] In one embodiment, the cover plate body 2 is further provided with a pressure relief hole 23, and the cover plate assembly also includes a pressure relief valve 6, which is installed in the pressure relief hole 23. The pressure relief valve 6 is adapted to open when the gas pressure inside the battery cell reaches a preset value to release the gas inside the battery cell and prevent the battery cell from exploding. A pressure relief valve patch 7 is attached to the upper side of the pressure relief hole 23 to protect the pressure relief valve 6.

[0061] According to an embodiment of the present invention, in another aspect, a battery cell is also provided, such as... Figures 12 to 13 As shown, the battery cell includes: a housing 8, an electrode assembly 9, and the aforementioned cover plate assembly. The housing 8 has an open end; the electrode assembly 9 is placed in the inner cavity of the housing; the cover plate assembly covers the open end of the housing 8. The electrode assembly 9 includes an electrode assembly body and a tab, the tab being connected to one end of the electrode assembly body along the Z direction, and the tab being electrically connected to the terminal post 1 in the cover plate assembly. Optionally, the battery cell is a lithium-ion battery cell.

[0062] In one embodiment, the battery cell further includes an adapter piece 10, which is disposed between the electrode group 9 and the cover plate assembly. A portion of the adapter piece 10 is welded to the tab of the electrode group 9, and another portion is welded to the base plate 11 of the pole post 1, thereby realizing the electrical connection between the electrode group 9 and the pole post 1.

[0063] The following examples and comparative examples verify the impact of different parameter values ​​on the cover plate assembly. The parameter settings for the examples and comparative examples are shown in Table 1, and the corresponding verification results are shown in Table 2. The evaluation indicators are as follows: I. Appearance Requirements 1. The flange 13 is required to be fully folded and tightly fitted to the first plastic part after folding, and there should be no cracks at the root of the flange 13. 2. After the flange is folded, the flatness of the upper surface of pole post 1 should be less than 0.3 mm.

[0064] When the flange 13 is folded over, if the pole post 1 meets both of the above conditions, it is determined that the appearance meets the requirements; otherwise, it does not meet the requirements.

[0065] II. Strength Performance Requirements A thrust test was conducted on the finished cover plate assembly along the Z-direction. An 800 N thrust was applied to pole 1 in the Z-direction for 50,000 cycles. After the thrust test, the airtightness of the cover plate assembly was detected using a helium mass spectrometer. The pole is required to withstand an 800 N thrust in the Z-direction for 50,000 cycles, and the airtightness of the cover plate assembly must meet the requirements after the thrust test (leakage rate < 1 × 10⁻⁶). -7 Pa.m3 / s).

[0066] Table 1

[0067] Table 2

[0068] In Table 2, OK indicates qualified and NG indicates unqualified.

[0069] As can be seen from Tables 1 to 2, for the cover plate assemblies of Embodiments 1 to 10, all parameters are within the range defined in this application, the appearance of the folded edge 13 meets the requirements, the flatness of the upper surface of the pole post 1 is less than 0.3 mm, and the strength performance meets the requirements. That is, the pole post 1 can pass the thrust test and the airtightness of the cover plate assembly is good after the thrust test. The cover plate assemblies of Embodiments 1 to 10 are all qualified.

[0070] For the cover plate assembly in Comparative Example 1, the groove height h along the Z direction of the groove 131 is 0, meaning that no groove 131 is provided on the flange 13. Therefore, the appearance of the flange 13 after folding does not meet the requirements. The flatness of the upper surface of the pole post 1 is 0.45 mm, which is greater than 0.3 mm, indicating that the flatness of the pole post does not meet the requirements. Furthermore, the strength performance does not meet the requirements, meaning that the airtightness of the cover plate assembly is insufficient after the thrust test, and it fails the test. It is evident that when the flange 13 does not have a groove 131, it is difficult to guarantee the folding effect of the flange 13 and the structural strength of the pole post 1.

[0071] For the cover plate assembly of Comparative Example 2, the h / H value is 0.167, which is less than the lower limit of h / H of 0.2 specified in this application. Therefore, the appearance of the folded flange 13 does not meet the requirements, and the flatness of the upper surface of the pole post 1 is 0.37 mm, which is greater than 0.3 mm. The flatness of the pole post does not meet the requirements, and the strength performance does not meet the requirements. In other words, the cover plate assembly is not airtight after the thrust test and is unqualified. For the cover plate assembly of Comparative Example 3, the h / H value is 0.575, which is greater than the upper limit of h / H of 0.5 specified in this application. Although the appearance of the folded flange 13 meets the requirements, and the flatness of the upper surface of the pole post 1 meets the requirements, the strength performance does not meet the requirements. In other words, the cover plate assembly is not airtight after the thrust test and is unqualified. It can be seen that when h / H is within the range of 0.2 to 0.5 specified in this application, both flange strength and flange effect can be guaranteed simultaneously.

[0072] For the cover plate assembly of Comparative Example 4, the value of S1 / S is 0.326, which is less than the lower limit of S1 / S of 0.33 defined in this application. Therefore, the appearance of the folded flange 13 does not meet the requirements, and the flatness of the upper surface of the pole post 1 is 0.37 mm, which is greater than 0.3 mm. Consequently, the flatness of the pole post does not meet the requirements, and the strength performance does not meet the requirements. That is, the cover plate assembly has insufficient airtightness after the thrust test and is unqualified. For the cover plate assembly of Comparative Example 5, the value of S1 / S is 0.683, which is greater than the upper limit of S1 / S of 0.67 defined in this application. Although the appearance of the folded flange 13 meets the requirements, and the flatness of the upper surface of the pole post 1 meets the requirements, the strength performance does not meet the requirements. That is, the cover plate assembly has insufficient airtightness after the thrust test and is unqualified. It can be seen that when S1 / S is within the range of 0.33 to 0.67 defined in this application, both flange strength and flange effect can be guaranteed simultaneously.

[0073] Unless otherwise stated, the values ​​of all parameters mentioned in this application can be determined using testing methods commonly used in the art. Unless otherwise stated, the test temperature for all parameters is 25°C.

[0074] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A pole post structure, characterized in that, include: Base plate; A column is connected to one side of the base plate along the Z direction, the column having a first axis extending along the Z direction; A flange is connected to the end of the column away from the base plate along the Z direction. The flange is arranged around the circumferential edge of the column in the XY plane, and the flange extends along the Z direction before being folded. A groove is opened at the end of the flange near the column along the Z direction. The flange is adapted to be folded to be parallel to the XY plane in a direction away from the first axis under the action of external force.

2. The pole post structure according to claim 1, characterized in that, Before the flange is folded, the height of the flange along the Z direction is H, and the groove height along the Z direction is h, wherein h and H satisfy the relationship: 0.2≤h / H≤0.

5.

3. The pole post structure according to claim 2, characterized in that, The value of H is in the range of 1.5 mm ≤ H ≤ 4 mm.

4. The pole post structure according to claim 1, characterized in that, Before the flange is folded, the inner and outer contours of the flange in the XY plane are equal in size to the outer contour of the column in the XY plane. The perimeter of the column in the XY plane is S, and the total arc length of the groove along the circumference of the column is S1. S1 and S satisfy the following relationship: 0.33≤S1 / S≤0.

67.

5. The pole post structure according to claim 4, characterized in that, The column is a cylinder with a diameter of D, where the value of D ranges from 10 mm to 25 mm.

6. The pole post structure according to claim 1, characterized in that, The number of the grooves is multiple, and the multiple grooves are distributed circumferentially along the column in the XY plane.

7. The pole post structure according to any one of claims 1 to 6, characterized in that, Before the flange is folded, the groove is a through groove that penetrates the flange radially along the column.

8. The pole post structure according to claim 1, characterized in that, The thickness of the folded edge along the Z direction is T, where the value of T ranges from 0.5 mm to 2.5 mm.

9. A cover plate assembly, characterized in that, include: The cover plate body has pole hole; The pole post is formed by folding the pole post structure according to any one of claims 1 to 8, wherein the pole post body is inserted into the pole post hole.

10. A battery cell, characterized in that, include: The shell has an open end; The electrode assembly is disposed within the inner cavity of the housing; The cover assembly of claim 9 is disposed over the opening end of the housing.

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