Cover plate assembly of battery

Abstract

The utility model provides a cover plate assembly of a battery, which comprises a cover plate and a sealing nail, and the cover plate and the sealing nail are both made of steel. A liquid injection hole is formed in the cover plate, the sealing nail abuts against the first side face in the thickness direction of the cover plate and covers the liquid injection hole, and the sealing nail and the first side face of the cover plate are welded to form a welding seam. The structural strength of steel is greater than that of aluminum, so that under the condition that the structural strength of the cover plate and the sealing nail which are made of steel are the same, the thickness of the cover plate and the sealing nail can be reduced compared with the cover plate and the sealing nail which are made of traditional aluminum, a larger mounting space is reserved for the battery core, and the electric quantity of the battery is improved. The sealing nail is directly welded to one side face of the cover plate in the thickness direction, the problem that the welding space is reduced due to the fact that the thickness of the sealing nail is reduced does not need to be considered, it can be guaranteed that enough welding space is formed between the sealing nail and the cover plate, and therefore the welding strength of the sealing nail and the cover plate and the sealing reliability are guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to power battery technical field, especially a battery's cover plate subassembly. BACKGROUND

[0002] In the manufacturing process of the secondary battery (for example, lithium ion battery), after completing the liquid injection process, the injection hole on the housing cover plate is laser sealed and welded by the sealing member to prevent the leakage of electrolyte and ensure the air tightness of the secondary battery.

[0003] The prior art is to process a sink on the cover plate and put the sealing member into the sink, and to realize the sealing connection of the sealing member and the cover plate by welding between the outer peripheral wall of the sealing member and the inner peripheral wall of the sink. However, this scheme needs to select a sealing member with sufficient thickness, so as to ensure the reliability of the welding seal. The cover plate and the sealing member made of traditional aluminum material usually have sufficient thickness to be able to be processed by the above-mentioned process, in order to ensure the strength of the structure. However, if the materials of the cover plate and the sealing member are changed and the thickness of the sealing member is reduced, it is difficult to ensure the reliability of the welding seal by connecting the cover plate and the sealing member by the above-mentioned process. SUMMARY

[0004] The utility model wants to solve the technical problem that in order to overcome the defect in the prior art, provide a battery's cover plate subassembly.

[0005] The utility model solves the above technical problem by the following technical scheme:

[0006] A battery's cover plate subassembly, the battery's cover plate subassembly includes the cover plate and the sealing nail, the material of the cover plate and the sealing nail is steel material;

[0007] The cover plate is equipped with injection hole, the sealing nail is abutted with the first side surface in the thickness direction of the cover plate and covers the injection hole, the sealing nail is welded with the first side surface of the cover plate and forms the weld.

[0008] In the present scheme, the structural strength of steel is greater than that of aluminum, so the thickness of the cover plate and the sealing nail made of steel material can be reduced compared with the cover plate and the sealing nail made of traditional aluminum material under the condition of the same structural strength, which reserves more installation space for the battery cell and improves the capacity of the battery. The sealing nail is directly welded with one side surface in the thickness direction of the cover plate, without considering the problem of reduced welding space caused by the reduction of the thickness of the sealing nail, so that the sealing nail and the cover plate have sufficient welding space, thereby ensuring the welding strength of the sealing nail and the cover plate and the reliability of the seal.

[0009] Preferably, the cover plate is provided with a limiting groove at one end thereof in the thickness direction thereof away from the liquid injection hole, and the sealing nail is at least partially accommodated in the limiting groove, and the outer peripheral wall of the sealing nail abuts against the inner peripheral wall of the limiting groove.

[0010] In this scheme, the limiting groove is used to quickly position the sealing nail on the cover plate, and can limit the movement of the sealing nail on the cover plate, prevent the displacement of the sealing nail during the welding process, ensure the welding quality, and improve the sealing effect.

[0011] Preferably, the first side surface of the cover plate is recessed in the thickness direction of the cover plate to form the limiting groove toward the inner side of the cover plate.

[0012] Alternatively, the cover plate is provided with an annular first protruding portion, the first side surface of the cover plate is protruded in the thickness direction of the cover plate to form the first protruding portion toward the outer side of the cover plate, and the inner peripheral wall of the first protruding portion and the first side surface of the cover plate enclose the limiting groove.

[0013] In this scheme, the limiting groove is formed by recessing the cover plate, which is simple in forming mode, easy to process, and reduces material waste. The limiting groove formed by the first protruding portion can reduce the thickness of other parts of the cover plate, reserve more installation space for the battery cell, and improve the capacity of the battery.

[0014] Preferably, the cover plate is further provided with a sunken groove, the sunken groove is provided on the side of the liquid injection hole close to the sealing nail in the thickness direction of the cover plate, one end of the sunken groove in the thickness direction of the cover plate is in communication with the liquid injection hole, the other end of the sunken groove in the thickness direction of the cover plate penetrates through the cover plate, and the sealing nail covers the sunken groove.

[0015] In this scheme, the sunken groove is used to avoid the interference between the sealing nail and the sealing glue nail for plugging the liquid injection hole, and improve the reliability of the liquid injection hole sealing.

[0016] Preferably, the cover plate assembly of the battery satisfies one or more of the following conditions:

[0017] a1, the cover plate is recessed in the thickness direction thereof toward the direction close to the liquid injection hole to form the sunken groove;

[0018] Alternatively, the cover plate further comprises an annular second protruding portion, the cover plate is protruded in the thickness direction thereof to form the second protruding portion toward the side away from the liquid injection hole, the inner peripheral wall of the second protruding portion and the first side surface of the cover plate enclose the sunken groove, and the sealing nail abuts against the end face of the second protruding portion in the thickness direction of the cover plate away from the liquid injection hole.

[0019] In the scheme, the forming mode of the sink formed by the cover plate recess is simple, easy to process, and reduces material waste. By setting the second protruding part to form the sink, compared with the traditional method of directly opening a hole on the flat cover plate to form a sink, no space is reserved on the cover plate for the sink, further reducing the thickness of the cover plate, reserving more installation space for the battery cell, and improving the battery capacity.

[0020] b1, the distance d1 between the inner circumferential end of the weld and the circumferential wall of the sink in the radial direction of the liquid injection hole is 1-5mm.

[0021] In the scheme, the above setting is used to ensure that the sealing nail and the cover plate have sufficient welding space to ensure the welding quality and improve the sealing effect of the liquid injection hole.

[0022] Preferably, the sealing nail is provided with a positioning groove away from one side of the liquid injection hole in the thickness direction of the cover plate, and the positioning groove is located at the geometric center of the sealing nail.

[0023] In the scheme, the positioning groove is used to facilitate the quick positioning of the welding area of the sealing nail and the cover plate by the welding robot and other equipment, and improve the precision of automatic welding.

[0024] Preferably, the cover plate assembly of the battery satisfies one or more of the following conditions:

[0025] a2, the depth of the positioning groove in the thickness direction of the cover plate is defined as d2; d2=0.2*T~0.3*T; wherein T is the thickness of the sealing nail in the thickness direction of the cover plate;

[0026] In the scheme, by reasonably setting the depth of the positioning groove, it is prevented that the positioning groove is too shallow to facilitate machine recognition, and the positioning groove is too deep to avoid that the strength of the sealing nail at the positioning groove is too low.

[0027] b2, the diameter D of the positioning groove is 2-5mm.

[0028] In the scheme, by reasonably setting the diameter of the positioning groove, it is prevented that the positioning groove is too small to facilitate machine recognition, and the positioning groove is too large to occupy the welding space of the sealing nail.

[0029] Preferably, the sealing nail comprises a third protruding part, the sealing nail protrudes to form the third protruding part away from one side of the liquid injection hole in the thickness direction of the cover plate, and the third protruding part forms an avoidance groove at one end thereof in the thickness direction of the cover plate and toward the liquid injection hole.

[0030] The cover plate assembly of the battery further comprises a sealing glue nail, the sealing glue nail cooperates with the liquid injection hole, and the sealing glue nail is partially located in the avoidance groove.

[0031] In the scheme, the above setting replaces the traditional sink groove on the cover plate with the design of the avoidance groove on the sealing nail, thereby not reserving the space occupied by the sink groove on the cover plate, further reducing the thickness of the cover plate, reserving more installation space for the battery cell, and improving the battery capacity.

[0032] Preferably, the cover plate assembly of the battery satisfies one or more of the following conditions:

[0033] a3, the height of the third protruding part in the thickness direction of the cover plate is defined as h; h=0.5*T~2*T; wherein T is the thickness of the sealing nail in the thickness direction of the cover plate;

[0034] In the scheme, by reasonably setting the height of the third protruding part, the third protruding part is prevented from being too low to cause interference between the sealing nail and the sealing glue nail, and the third protruding part is prevented from being too high to occupy too much external space of the battery.

[0035] b3, the distance d3 between the outer circumferential wall of the third protruding part and the inner circumferential end of the weld in the radial direction of the liquid injection hole is 1-5mm;

[0036] In the scheme, the above setting is used to ensure that the sealing nail and the cover plate have sufficient welding space to ensure the welding quality and improve the sealing effect of the liquid injection hole.

[0037] c3, the distance d4 between the circumferential wall of the liquid injection hole and the circumferential wall of the avoidance groove in the radial direction of the liquid injection hole is greater than or equal to 1mm.

[0038] In the scheme, the above setting is used to avoid interference between the sealing nail and the sealing glue nail.

[0039] Preferably, the cover plate assembly of the battery satisfies one or more of the following conditions:

[0040] a4, the thickness T of the sealing nail in the thickness direction of the cover plate is 0.4-1mm;

[0041] In the scheme, since the sealing nail is made of steel material, the thickness of the sealing nail can be reduced compared to the thickness of the aluminum material sealing nail, thereby reserving more installation space for the battery cell and improving the battery capacity.

[0042] b4, the distance d5 between the outer circumferential wall of the sealing nail and the outer circumferential end of the weld in the radial direction of the liquid injection hole is 1-5mm;

[0043] In the scheme, the above setting is used to ensure that the sealing nail and the cover plate have sufficient welding space to ensure the welding quality and improve the sealing effect of the liquid injection hole.

[0044] c4, the sealing nail and the first side of the cover plate are connected by laser penetration welding.

[0045] In the scheme, the laser penetration welding energy is concentrated, the welding efficiency is high, and the machining precision is high.

[0046] d4, the material of the cover plate and the sealing nail is stainless steel;

[0047] In the scheme, the stainless steel is more corrosion-resistant, and the service life of the cover plate assembly can be improved.

[0048] e3, the cross section of the sealing nail in the thickness direction perpendicular to the cover plate is any one of a circle, a rectangle, an ellipse and a triangle.

[0049] In the scheme, the design flexibility of the sealing nail is high.

[0050] The positive progress effect of the utility model lies in that the structural strength of steel is greater than that of aluminum, so that the thickness of the cover plate and the sealing nail made of steel can be reduced compared with the cover plate and the sealing nail made of traditional aluminum under the condition of the same structural strength, more installation space is reserved for the battery cell, and the capacity of the battery is improved. The sealing nail is directly welded with one side surface in the thickness direction of the cover plate, the problem of reduced welding space caused by the reduced thickness of the sealing nail does not need to be considered, sufficient welding space between the sealing nail and the cover plate can be ensured, so that the welding strength of the sealing nail and the cover plate is ensured, and the reliability of sealing is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 It is a top view structural schematic diagram of the cover plate assembly of the battery of the utility model embodiment 1.

[0052] Figure 2 It is a top view structural schematic diagram of the cover plate assembly of the battery of the utility model embodiment 1.

[0053] Figure 3 It is Figure 2 It is an enlarged view of A of the utility model embodiment 1.

[0054] Figure 4 It is a three-dimensional structural schematic diagram of the sealing nail of the utility model embodiment 1.

[0055] Figure 5 It is a sectional view structural schematic diagram of the sealing nail of the utility model embodiment 1.

[0056] Figure 6 It is a top view structural schematic diagram of the cover plate assembly of the battery of the utility model embodiment 2.

[0057] Figure 7 It is a partial internal structure schematic diagram of the cover plate assembly of the battery of the utility model embodiment 2.

[0058] Figure 8It is the overhead structure schematic drawing of the battery's cover plate subassembly of the embodiment 3 of the utility model.

[0059] Figure 9 It is the partial internal structure schematic drawing of the battery's cover plate subassembly of the embodiment 3 of the utility model.

[0060] Figure 10 It is the three-dimensional structure schematic drawing of the sealing nail of the embodiment 3 of the utility model.

[0061] Figure 11 It is the sectional structure schematic drawing of the sealing nail of the embodiment 3 of the utility model.

[0062] Figure 12 It is the overhead structure schematic drawing of the battery's cover plate subassembly of the embodiment 4 of the utility model.

[0063] Figure 13 It is the partial internal structure schematic drawing of the battery's cover plate subassembly of the embodiment 4 of the utility model.

[0064] Explanation of reference signs:

[0065] Cover plate 1

[0066] Sunk groove 11

[0067] Liquid injection hole 12

[0068] First side surface 13

[0069] Limiting groove 14

[0070] First protruding part 15

[0071] Second protruding part 16

[0072] Sealing nail 2

[0073] Positioning groove 21

[0074] Third protruding part 22

[0075] Avoidance groove 23

[0076] Pole 3

[0077] Sealing glue nail 4

[0078] Weld 5 Specific implementation

[0079] The utility model will be described below with a preferred embodiment and in connection with the drawings.

[0080] Embodiment 1

[0081] As Figures 1-3As shown, the present embodiment discloses a cover plate assembly of a battery, which is used to cooperate with a battery shell to assemble a housing of the battery.

[0082] As shown, Figures 1-3 the cover plate assembly comprises a cover plate 1, a sealing pin 2, a pole 3 and a sealing glue pin 4.

[0083] As shown, Figure 3 the cover plate 1 is sequentially provided with a sink 11 and a liquid injection hole 12 along the thickness direction thereof, the sink 11 and the liquid injection hole 12 both extend along the thickness direction of the cover plate 1 (X direction in the figure), Figure 2 the sink 11 is coaxial with the liquid injection hole 12 and the diameter of the sink 11 is greater than that of the liquid injection hole 12, and the sink 11 in the present embodiment is formed by recessing the cover plate 1 along the thickness direction thereof towards the liquid injection hole 12. One end of the sink 11 penetrates one side surface of the cover plate 1 in the thickness direction thereof, the other end of the sink 11 communicates with the liquid injection hole 12, and the other end of the liquid injection hole 12 penetrates the other side surface of the cover plate 1 in the thickness direction thereof, so that electrolyte can be injected from the outside of the battery housing to the inside of the battery housing through the sink 11 and the liquid injection hole 12.

[0084] As shown, Figure 3 the sealing glue pin 4 is inserted into the liquid injection hole 12 to seal the liquid injection hole 12, prevent the electrolyte in the inside of the battery housing from leaking, and improve the air tightness of the battery. The sealing glue pin 4 in the present embodiment can be made of elastic members such as rubber, and the sealing glue pin 4 is in interference fit with the liquid injection hole 12 to improve the sealing of the liquid injection hole 12. In other alternative embodiments, the sealing glue pin 4 can also be made of other non-elastic materials as long as it can be used to seal the liquid injection hole 12.

[0085] As shown, Figure 3 and Figure 4 the sealing pin 2 and the pole 3 are both installed on the side surface of the cover plate 1 in the thickness direction thereof close to the sink 11 (the side surface is referred to as the first side surface 13 of the cover plate 1), and the cross-sectional shape of the sealing pin 2 perpendicular to the thickness direction of the cover plate 1 is circular in the present embodiment, and the cross-sectional diameter of the sealing pin 2 is greater than the diameter of the sink 11. The sealing pin 2 abuts against the first side surface 13 in the thickness direction of the cover plate 1 and completely covers the slot of the sink 11, so as to cover the liquid injection hole 12 and further prevent the electrolyte in the inside of the battery housing from leaking, and improve the air tightness of the battery.

[0086] Further, as shown, Figure 3 part of the sealing glue pin 4 is accommodated in the sink 11, the sink 11 is used to avoid the sealing glue pin 4 blocking the liquid injection hole 12, prevent the sealing pin 2 from interfering with the sealing pin 2, and improve the reliability of the sealing of the liquid injection hole 12.

[0087] In other alternative embodiments, the cross-sectional shape of the sealing nail 2 in the thickness direction perpendicular to the cover plate 1 can also be other shapes, such as rectangular, oval, triangular, etc., as long as the cross-sectional size of the sealing nail 2 is greater than the diameter of the sink 11 to ensure that the sealing nail 2 can completely cover the opening of the sink 11. The shape of the sealing nail 2 has low shape restrictions and high design flexibility.

[0088] As shown in Figure 3 , the cover plate 1 is provided with a limiting groove 14 at one end thereof in the thickness direction away from the liquid injection hole 12, and the sealing nail 2 is partially accommodated in the limiting groove 14, and the outer peripheral wall of the sealing nail 2 abuts against the inner peripheral wall of the limiting groove 14. The limiting groove 14 is used to achieve rapid positioning of the sealing nail 2 on the cover plate 1, and can limit the movement of the sealing nail 2 on the cover plate 1 to prevent displacement of the sealing nail 2 during the welding process, thereby ensuring the welding quality and improving the sealing effect.

[0089] Specifically, as shown in Figure 3 , in this embodiment, the first side surface 13 of the cover plate 1 is recessed to form the limiting groove 14 in the thickness direction of the cover plate 1 towards the inner side of the cover plate 1. The forming method of recessing the limiting groove 14 from the cover plate 1 is simple, easy to process, and reduces material waste.

[0090] In other alternative embodiments, the sealing nail 2 can also be completely accommodated in the limiting groove 14 as long as the depth of the limiting groove 14 is sufficient.

[0091] The materials of the cover plate 1 and the sealing nail 2 in this embodiment are both steel materials, specifically stainless steel materials such as SUS304, SUS316L, etc. Stainless steel is more corrosion-resistant and can improve the service life of the cover plate assembly. In other alternative embodiments, the materials of the cover plate 1 and the sealing nail 2 can also be non-stainless steel steel materials.

[0092] Further, the material of the battery shell cooperating with the cover plate assembly is also steel to facilitate the assembly of the two. The materials of the cover plate 1, the sealing nail 2 and the battery shell can be the same steel material, or different steel materials can be selected according to requirements.

[0093] Since the structural strength of steel is greater than that of aluminum, the cover plate 1 and the sealing nail 2 in this embodiment are made of steel, and under the condition of the same strength, the thickness of the cover plate 1 and the sealing nail 2 can be reduced compared to the cover plate 1 and the sealing nail 2 made of traditional aluminum. The thickness T of the sealing nail 2 in the thickness direction of the cover plate 1 in this embodiment is 0.4-1mm. In the case of the same size of the battery shell, more installation space is reserved for the battery cell inside the battery shell to improve the battery capacity. Moreover, the battery shell made of steel is more resistant to high temperature and can withstand greater pressure, and is less likely to have a serious burn-through phenomenon, thereby reducing the risk of thermal diffusion of the battery cell.

[0094] In other alternative embodiments, the thickness of the sealing nail 2 can also be designed as other values according to actual conditions.

[0095] Due to the reduction of the thickness of the cover plate 1 and the sealing nail 2, if the traditional welding method of welding the outer peripheral wall of the sealing nail 2 with the inner peripheral wall of the sink 11 of the cover plate 1 is still adopted, the welding space of the cover plate 1 and the sealing nail 2 will be reduced, which will affect the welding effect. Therefore, in the present embodiment, the sealing nail 2 is welded with the first side 13 of the cover plate 1, so that the problem of the reduction of the welding space due to the reduction of the thickness of the sealing nail 2 is not considered, and sufficient welding space between the sealing nail 2 and the cover plate 1 can be ensured, so as to ensure the welding strength of the sealing nail 2 and the cover plate 1 and the reliability of the sealing.

[0096] In the present embodiment, the sealing nail 2 and the first side 13 of the cover plate 1 are connected by laser penetration welding, and the laser penetration welding has the advantages of concentrated energy, high welding efficiency and high machining precision. In other alternative embodiments, the sealing nail 2 and the first side 13 of the cover plate 1 can also be welded by other welding methods.

[0097] As shown in Figure 3 , the welding seam 5 is formed in the welding area of the sealing nail 2 and the cover plate 1, the distance d5 between the outer peripheral wall of the sealing nail 2 and the outer peripheral end of the welding seam 5 in the radial direction of the liquid injection hole 12 is 1-5mm, and the distance d1 between the inner peripheral end of the welding seam 5 and the peripheral side wall of the sink 11 in the radial direction of the liquid injection hole 12 is 1-5mm, so as to ensure that the sealing nail 2 and the cover plate 1 have sufficient welding space to ensure the welding quality and improve the sealing effect of the liquid injection hole 12.

[0098] In other alternative embodiments, the distance between the outer peripheral wall of the sealing nail 2 and the outer peripheral end of the welding seam 5 and the distance between the inner peripheral end of the welding seam 5 and the peripheral side wall of the sink 11 can also be designed as other values according to actual conditions.

[0099] As shown in Figure 4 and Figure 5 , the positioning groove 21 is arranged on the side of the sealing nail 2 away from the liquid injection hole 12 in the thickness direction of the cover plate 1, and the positioning groove 21 is recessed from the side of the sealing nail 2 away from the liquid injection hole 12 in the thickness direction of the cover plate 1 to the inside of the sealing nail 2. The positioning groove 21 is arranged at the geometric center of the sealing nail 2, and the positioning groove 21 is used for facilitating the positioning of the welding area of the sealing nail 2 and the cover plate 1 by the welding robot and other equipment, and improving the precision of automatic welding.

[0100] As shown in Figure 5As shown, the depth of the positioning groove 21 in the thickness direction of the cover plate 1 is defined as d2, d2 = 0.2*T~0.3*T, that is, the depth of the positioning groove 21 is 0.2~0.3 times the thickness of the sealing nail 2. In this embodiment, the depth of the positioning groove 21 is reasonably set to prevent the positioning groove 21 from being too shallow to facilitate machine recognition and prevent the positioning groove 21 from being too deep to avoid the sealing nail 2 at the positioning groove 21 being too low in strength. In other alternative embodiments, the depth of the positioning groove 21 can also be designed to other values according to actual conditions.

[0101] Further, as shown in Figure 5 , the diameter D of the positioning groove 21 is 2~5mm, and in this embodiment, the diameter of the positioning groove 21 is reasonably set to prevent the positioning groove 21 from being too small to facilitate machine recognition and prevent the positioning groove 21 from being too large to occupy the welding space of the sealing nail 2. In other alternative embodiments, the diameter of the positioning groove 21 can also be designed to other values according to actual conditions.

[0102] Embodiment 2

[0103] The structure of the cover plate assembly of the battery in this embodiment is basically the same as that of Embodiment 1, and the difference is that:

[0104] As shown in Figure 6 and Figure 7 , the cover plate 1 is provided with a first protruding portion 15 at one end thereof away from the liquid injection hole 12 in the thickness direction thereof, the first protruding portion 15 is formed by the first side surface 13 of the cover plate 1 protruding outward along the thickness direction of the cover plate 1, and the inner peripheral wall of the first protruding portion 15 and the first side surface 13 of the cover plate 1 form a limiting groove 14.

[0105] In this embodiment, the way of forming the limiting groove 14 by the first protruding portion 15 can reduce the thickness of other parts of the cover plate 1, reserve more installation space for the battery cell, and improve the capacity of the battery.

[0106] Embodiment 3

[0107] The structure of the cover plate assembly of the battery in this embodiment is basically the same as that of Embodiment 1, and the difference is that:

[0108] As shown in Figures 8-11 , the sealing nail 2 comprises a third protruding portion 22, the third protruding portion 22 is formed by the sealing nail 2 protruding away from the side of the liquid injection hole 12 in the thickness direction of the cover plate 1, and the thickness of the third protruding portion 22 of the sealing nail 2 is the same as that of other positions of the sealing nail 2, so that the third protruding portion 22 forms an avoiding groove 23 at one end thereof in the thickness direction of the cover plate 1.

[0109] As shown in Figure 9As shown, the cover plate 1 in the embodiment does not have a sink groove 11, but relies on the avoidance groove 23 of the sealing nail 2 to accommodate part of the sealing glue nail 4, so as to avoid interference between the sealing nail 2 and the sealing glue nail 4. The embodiment replaces the sink groove 11 on the traditional cover plate 1 with the avoidance groove 23 designed on the sealing nail 2, so that the space occupied by the sink groove 11 on the cover plate 1 is not reserved, further reducing the thickness of the cover plate 1, reserving more installation space for the battery cell, and improving the battery capacity.

[0110] In the embodiment, the distance d4 between the circumferential wall of the liquid injection hole 12 and the circumferential wall of the avoidance groove 23 in the radial direction of the liquid injection hole 12 is greater than or equal to 1 mm, so as to avoid interference between the sealing nail 2 and the sealing glue nail 4. In other alternative embodiments, the distance between the circumferential wall of the liquid injection hole 12 and the circumferential wall of the avoidance groove 23 can also be designed to other values according to actual requirements.

[0111] Further, the sealing nail 2 in the embodiment also does not need to be separately provided with a positioning groove 21, and the third protruding part 22 of the sealing nail 2 can replace the function of the positioning groove 21, so as to be easily recognized by a welding robot or other equipment, so as to facilitate welding of the cover plate 1 and the sealing nail 2. Moreover, since the diameter of the third protruding part 22 is obviously greater than the diameter of the positioning groove 21, the third protruding part 22 can be more easily recognized by the equipment.

[0112] As shown in FIG. 1, Figure 11 the height of the third protruding part 22 in the thickness direction of the cover plate 1 is defined as h, h = 0.5*T~2*T, that is, the height of the third protruding part 22 is 0.5~2 times the thickness of the sealing nail 2. The embodiment reasonably sets the height of the third protruding part 22, so as to prevent the third protruding part 22 from being too low to cause interference between the sealing nail 2 and the sealing glue nail 4, and prevent the third protruding part 22 from being too high to occupy too much external space of the battery.

[0113] In other alternative embodiments, the height of the third protruding part 22 can also be designed to other values according to actual requirements.

[0114] Further, as shown in FIG. 1, Figure 9 the distance d3 between the outer circumferential wall of the third protruding part 22 and the inner circumferential end of the weld 5 in the radial direction of the liquid injection hole 12 is 1-5 mm, so as to ensure that the sealing nail 2 and the cover plate 1 have sufficient welding space, so as to ensure the welding quality and improve the sealing effect of the liquid injection hole 12. In other alternative embodiments, the distance between the outer circumferential wall of the third protruding part 22 and the inner circumferential end of the weld 5 can also be designed to other values according to actual requirements.

[0115] Embodiment 4

[0116] The structure of the cover plate assembly of the battery in the embodiment is basically the same as that of the embodiment 1, and the difference is that:

[0117] As shown in FIG. 1, Figure 12 andFigure 13 As shown, the cover plate 1 further comprises a second protruding part 16, the cover plate 1 is protruded along the thickness direction to form the second protruding part 16 away from the liquid injection hole 12, the inner circumferential wall of the second protruding part 16 and the first side surface 13 of the cover plate 1 form the sink 11, and the sealing nail 2 abuts against the end surface of the second protruding part 16 away from the liquid injection hole 12 in the thickness direction of the cover plate 1.

[0118] The second protruding part 16 is arranged to form the sink 11 in the embodiment, compared with the traditional method of directly opening a hole on the flat cover plate 1 to form the sink 11, the space occupied by the sink 11 on the cover plate 1 is not reserved, the thickness of the cover plate 1 is further reduced, more installation space is reserved for the battery cell, and the battery capacity is improved.

[0119] In the description of the utility model, it is understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship of the device or component shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the utility model.

[0120] Although the specific embodiments of the utility model are described above, those skilled in the art should understand that this is only an example, the protection scope of the utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the utility model, but these changes and modifications all fall within the protection scope of the utility model.

Claims

1. A cover plate assembly for a battery, comprising: The cover plate assembly of the battery comprises a cover plate and a sealing nail, and the materials of the cover plate and the sealing nail are both steel; The cover plate is provided with a liquid injection hole, the sealing nail abuts against a first side of the cover plate in the thickness direction of the cover plate and covers the liquid injection hole, and the sealing nail is welded with the first side of the cover plate and forms a weld.

2. The cover plate assembly of the battery according to claim 1, wherein The cover plate is provided with a limiting groove at one end thereof away from the liquid injection hole in the thickness direction of the cover plate, and the sealing nail is at least partially accommodated in the limiting groove, and the outer peripheral wall of the sealing nail abuts against the inner peripheral wall of the limiting groove.

3. The cover plate assembly of claim 2, wherein, The first side of the cover plate is recessed towards the inner side of the cover plate in the thickness direction of the cover plate to form the limiting groove; Alternatively, the cover plate is provided with an annular first protruding portion, the first side of the cover plate is protruded towards the outer side of the cover plate in the thickness direction of the cover plate to form the first protruding portion, and the inner peripheral wall of the first protruding portion and the first side of the cover plate enclose the limiting groove.

4. The cover plate assembly of claim 1, wherein, The cover plate is further provided with a sunken groove, the sunken groove is arranged on the side of the liquid injection hole close to the sealing nail in the thickness direction of the cover plate, one end of the sunken groove in the thickness direction of the cover plate is communicated with the liquid injection hole, the other end of the sunken groove in the thickness direction of the cover plate penetrates through the cover plate, and the sealing nail covers the sunken groove.

5. The cover plate assembly of claim 4, wherein, The cover plate assembly of the battery satisfies one or more of the following conditions: a1, the cover plate is recessed towards the direction close to the liquid injection hole in the thickness direction of the cover plate to form the sunken groove; Alternatively, the cover plate further comprises an annular second protruding portion, the cover plate is protruded towards the side away from the liquid injection hole in the thickness direction of the cover plate to form the second protruding portion, the inner peripheral wall of the second protruding portion and the first side of the cover plate enclose the sunken groove, and the sealing nail abuts against the end face of the second protruding portion away from the liquid injection hole in the thickness direction of the cover plate; b1, the distance d1 between the inner peripheral end of the weld and the peripheral side wall of the sunken groove in the radial direction of the liquid injection hole is 1-5 mm.

6. The cover plate assembly of claim 4, wherein, The sealing nail is provided with a positioning groove on the side thereof away from the liquid injection hole in the thickness direction of the cover plate, and the positioning groove is arranged at the geometric center of the sealing nail.

7. The cover plate assembly of claim 6, wherein, The cover plate assembly of the battery satisfies one or more of the following conditions: a2, the depth of the positioning groove in the thickness direction of the cover plate is defined as d2; d2=0.2*T-0.3*T; wherein T is the thickness of the sealing nail in the thickness direction of the cover plate; b2, the diameter D of the positioning groove is 2-5 mm.

8. The cover plate assembly of the battery of claim 1, wherein, The sealing nail comprises a third protruding portion, the sealing nail is protruded towards the side away from the liquid injection hole in the thickness direction of the cover plate to form the third protruding portion, and the third protruding portion forms an avoiding groove towards the liquid injection hole in the thickness direction of the cover plate; The cover plate assembly of the battery further comprises a sealing glue nail, the sealing glue nail cooperates with the liquid injection hole, and the sealing glue nail is partially located in the avoiding groove.

9. The cover plate assembly of claim 8, wherein, The cover plate assembly of the battery satisfies one or more of the following conditions: a3, the height of the third protruding part in the thickness direction of the cover plate is defined as h; h=0.5*T~2*T; wherein T is the thickness of the sealing nail in the thickness direction of the cover plate; b3, the distance d3 between the outer circumferential wall of the third protruding part and the inner circumferential end of the weld in the radial direction of the liquid injection hole is 1-5mm; c3, the distance d4 between the circumferential wall of the liquid injection hole and the circumferential wall of the avoiding groove in the radial direction of the liquid injection hole is greater than or equal to 1mm.

10. The cover plate assembly of any one of claims 1-9, wherein, The cover plate assembly of the battery satisfies one or more of the following conditions: a4, the thickness T of the sealing nail in the thickness direction of the cover plate is 0.4-1mm; b4, the distance d5 between the outer circumferential wall of the sealing nail and the outer circumferential end of the weld in the radial direction of the liquid injection hole is 1-5mm; c4, the sealing nail and the first side of the cover plate are connected by laser penetration welding; d4, the materials of the cover plate and the sealing nail are both stainless steel; e4, the shape of the cross section of the sealing nail perpendicular to the thickness direction of the cover plate is any one of circular, rectangular, elliptical, triangular.

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