Secondary battery and cover plate assembly thereof

Abstract

Embodiments of the present application disclose a secondary battery and a cover plate assembly thereof, the cover plate assembly comprising a cover main body, a pole portion, an insulating piece, and a first blocking part. The cover main body is used for sealing the opening of a casing of the secondary battery and is provided with an electrolyte injection hole; the insulating piece is sandwiched between the pole portion and the cover main body such that the pole portion is electrically insulated from the cover main body, and the insulating piece and the electrolyte injection hole are spaced apart in a first direction. The first blocking part is integrally formed on the cover main body by means of a stamping process, such that a protrusion or a recess is formed on the surface of the side of the cover main body facing away from an accommodating cavity, and at least part of the first blocking part is located between the electrolyte injection hole and the insulating piece in the first direction so as to block electrolyte from spreading from the electrolyte injection hole to the insulating piece.

Description

Secondary battery and cover assembly thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 28, 2023, with application number 202311281052.6 and invention name “Secondary battery and its cover assembly”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to, but is not limited to, a secondary battery and a cover plate assembly thereof. Background Art

[0003] As secondary battery technology becomes increasingly mature, secondary batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of secondary batteries are increasing.

[0004] The cover assembly of the secondary battery is an accessory in the secondary battery. One function is to form a accommodating cavity isolated from the outside after welding with the shell. The other function is to connect the internal and external circuits and transmit the internal current of the secondary battery to the outside.

[0005] The cover plate assembly includes a plain aluminum plate, a pole, and an insulator. The insulator is positioned between the pole and the plain aluminum plate to provide electrical insulation. The plain aluminum plate is equipped with an injection hole. When electrolyte is injected through the injection hole, it easily overflows onto the insulator, reducing the insulating effectiveness of the insulator.

[0006] Application Contents

[0007] In one aspect, a cover assembly for a secondary battery is provided, comprising a cover body, a terminal, an insulating member, and a first blocking portion. The cover body is used to seal the opening of the secondary battery housing to form a receiving cavity with the housing. The cover body has an injection hole that communicates with the receiving cavity for injecting electrolyte into the receiving cavity through the injection hole. The terminal is disposed through the cover body, with a portion located outside the receiving cavity and another portion located inside the receiving cavity. The insulating member is sandwiched between the terminal and the cover body to electrically insulate the terminal from the cover body, with the insulating member and the injection hole spaced apart in a first direction. The first blocking portion is integrally formed on the cover body through a stamping process, such that a protrusion or depression is formed on the surface of the cover body facing away from the receiving cavity. At least a portion of the first blocking portion is located between the injection hole and the insulating member in the first direction to prevent electrolyte from spreading from the injection hole to the insulating member.

[0008] Optionally, the first blocking portion is arranged outside the liquid injection hole.

[0009] Optionally, the first blocking portion is a closed ring; or, the first blocking portion is a ring with an opening, and the opening is located on a side of the first blocking portion away from the insulating member in the first direction.

[0010] Optionally, the first blocking portion is in the shape of an elongated strip, extending in a second direction intersecting the first direction, and optionally, the second direction is perpendicular to the first direction; or, the first blocking portion is in the shape of a wave, protruding alternately toward the insulating part and the injection hole on the extension path; or, the first blocking portion is in the shape of a "V", protruding toward the insulating part or the injection hole on the extension path.

[0011] Optionally, the cover assembly also includes a second blocking portion, which is integrally formed on the cover body through a stamping process so that a bulge or a depression is formed on the surface of the cover body facing away from the accommodating cavity, and at least a portion of the second blocking portion is located between the injection hole and the insulating member in the first direction to block the electrolyte from spreading from the injection hole to the insulating member; wherein, one of the first blocking portion and the second blocking portion forms a bulge on the surface of the cover body facing away from the accommodating cavity, and the other of the first blocking portion and the second blocking portion forms a depression on the surface of the cover body facing away from the accommodating cavity.

[0012] Optionally, the minimum distance between the first blocking portion and the edge of the cover body is L1 mm, the cover body is flat, the thickness of the cover body is T1 mm, the dimension of the cover body at the first blocking portion perpendicular to the first direction is L2 mm, and the outer diameter of the liquid injection hole is D1 mm, satisfying the following relationship:

[0013] 0.1*T1+1.8≤L1≤D1 / 4+1.75, where L2≤15;

[0014] 0.1*T1+1.8≤L1≤L2 / 4, where L2>15.

[0015] Optionally, the minimum distance between the first blocking portion and the edge of the cover body is L1 mm, and the dimension of the cover body at the first blocking portion perpendicular to the first direction is L2 mm, satisfying the following relationship:

[0016] 2≤L1≤3.75, where L2≤15;

[0017] 2≤L1≤L2 / 4, where L2>15.

[0018] Optionally, the minimum distance between the first blocking portion and the edge of the liquid injection hole is L3 mm, satisfying the following relationship: 2≤L3≤25.

[0019] Optionally, when the first blocking portion forms a bulge on the surface of the cover body facing away from the accommodating cavity, the protruding height of the first blocking portion is H1, and the height of the pole protruding from the surface of the cover body facing away from the accommodating cavity is H2, satisfying the following relationship: H1≤H2.

[0020] Optionally, the cover assembly further includes a cover patch, which is attached to at least the surface of the first blocking portion facing away from the cover body. The thickness of the cover patch is T2, satisfying the following relationship: H1+T2≤H2.

[0021] On the other hand, the present application also provides a secondary battery, including a shell, a cover plate assembly and an electrode assembly, wherein one side of the shell has an opening; the cover plate assembly covers the opening of the shell and is formed with the shell to form a accommodating cavity; the electrode assembly is accommodated in the accommodating cavity; wherein the cover plate assembly is any of the above-mentioned cover plate assemblies. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0023] FIG1 is a three-dimensional exploded view of an embodiment of a secondary battery of the present application;

[0024] FIG2 is a schematic diagram of a three-dimensional structure of a cover plate assembly in the related art;

[0025] FIG3 is a schematic diagram of the three-dimensional structure of an embodiment of a cover plate assembly of the present application;

[0026] FIG4 is a top view (partial) of the cover plate assembly shown in FIG3 ;

[0027] FIG5 is a cross-sectional view (partial) of the cover plate assembly shown in FIG3 ;

[0028] FIG6 is a schematic diagram of the three-dimensional structure of an embodiment of a cover plate assembly of the present application;

[0029] FIG7 is a top view (partial) of the cover plate assembly shown in FIG6 ;

[0030] FIG8 is a schematic diagram of the three-dimensional structure of an embodiment of a cover plate assembly of the present application;

[0031] FIG9 is a top view of an embodiment of a cover plate assembly of the present application;

[0032] FIG10 is a top view of an embodiment of a cover plate assembly of the present application;

[0033] FIG11 is a top view of an embodiment of a cover assembly of the present application;

[0034] FIG12 is a top view of an embodiment of a cover plate assembly of the present application;

[0035] FIG13 is a schematic diagram of the three-dimensional structure of an embodiment of a cover plate assembly of the present application;

[0036] FIG14 is a schematic diagram of the three-dimensional structure of an embodiment of a cover assembly of the present application;

[0037] FIG15 is a side view of an embodiment of a cover plate assembly of the present application;

[0038] FIG16 is a top view of an embodiment of a cover assembly of the present application.

[0039] Explanation of the reference numerals: 101 - shell; 103 - cover assembly; 105 - electrode assembly; 107 - insulating protective film; 109 - explosion-proof valve; 111 - cover body; 113 - liquid injection hole; 115 - pole; 117 - conductor; 119 - rivet; 116 - insulating member; 121 - lower plastic; 123 - top surface; 125 blocking part; 127 - opening; X - first direction; Y - second direction; Z - third direction. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and beneficial effects of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described in this specification are only for the purpose of explaining this application and are not intended to limit this application.

[0041] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise specifically specified.

[0042] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, direct connections, or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0043] A secondary battery is a battery that can be recharged after discharge to reactivate its active materials and allow continued use. A secondary battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. During the charge and discharge process, active ions are inserted and removed between the positive and negative electrodes. The separator is placed between the positive and negative electrodes to provide isolation. The electrolyte conducts ions between the positive and negative electrodes.

[0044] Please refer to Figure 1. Figure 1 is a three-dimensional exploded view of an embodiment of a secondary battery of the present application.

[0045] In some embodiments, a secondary battery includes a housing 101, two cover plate assemblies 103 (shown as two), and an electrode assembly 105. The housing 101 has an opening on one side. The cover plate assembly 103 covers the opening of the housing 101 and, together with the housing 101, forms a housing cavity. The electrode assembly 105 is housed in the housing cavity.

[0046] Specifically, in the embodiment shown in Figure 1, the shell 101 is generally in the shape of a rectangular box, with openings on both sides. Two cover plate assemblies 103 are respectively covered on the openings on both sides of the shell 101, and are surrounded to form a receiving cavity. The receiving cavity also contains electrolyte. The electrode assembly 105 includes the above-mentioned positive electrode sheet, negative electrode sheet, and isolation membrane. In some embodiments, the electrode assembly 105 is formed by winding the positive electrode sheet, the negative electrode sheet, and the isolation membrane. In other embodiments, the electrode assembly 105 is formed by stacking the positive electrode sheet, the negative electrode sheet, and the isolation membrane. In order to insulate the electrode assembly 105 from the shell 101, the secondary battery also includes an insulating protective film 107. The insulating protective film 107 is sleeved on the outside of the electrode assembly 105. The shell 101 is also provided with an explosion-proof valve 109 to release the high-pressure gas in the receiving cavity when the secondary battery thermally runs away.

[0047] In some other embodiments, the secondary battery may also be a square battery, that is, the housing 101 has only one side open and only one cover assembly 103 .

[0048] The present application does not limit the specific structure of the secondary battery, and the improvement of the present application mainly lies in the cover plate assembly 103 .

[0049] Please refer to Figure 2. Figure 2 is a schematic diagram of the three-dimensional structure of the cover assembly 103 in the related art.

[0050] In the related art, the cover assembly 103 includes a cover body 111 , a pole 115 , an insulating member 116 and a lower plastic 121 .

[0051] The cover body 111 is used to seal the opening of the secondary battery housing 101, thereby forming a housing cavity with the housing 101. Specifically, the cover body 111 is generally flat. The cover body 111 can be made of aluminum or an aluminum alloy. The cover body 111 and the housing 101 can be laser welded.

[0052] The cover body 111 has a top surface 123 and a bottom surface (not visible in the figure). The top surface 123 is the surface of the cover body 111 facing away from the accommodating cavity, and the bottom surface is the surface of the cover body 111 facing the accommodating cavity.

[0053] The lower plastic 121 is disposed on one side of the bottom surface of the cover body 111 . The lower plastic 121 can prevent the electrode assembly 105 from contacting the cover body 111 .

[0054] The cover body 111 has a liquid injection hole 113. The liquid injection hole 113 penetrates the cover body 111 in the direction between the top surface 123 and the bottom surface. The liquid injection hole 113 is connected to the accommodating cavity so that electrolyte can be injected into the accommodating cavity through the liquid injection hole 113.

[0055] The electrode 115 is disposed through the cover body 111, with a portion located outside the accommodating cavity and a portion located inside the accommodating cavity. Specifically, the electrode 115 includes a conductor 117 and a rivet 119. The conductor 117 is disposed through the cover body 111, with a portion located outside the accommodating cavity and a portion located inside the accommodating cavity. The rivet 119 is riveted to the portion of the conductor 117 located outside the accommodating cavity. The portion of the conductor 117 located inside the accommodating cavity is electrically connected to the electrode assembly 105.

[0056] The insulating member 116 is sandwiched between the pole 115 and the cover body 111 to electrically insulate the pole 115 from the cover body 111. Specifically, the insulating member 116 can be formed between the pole 115 and the cover body 111 by injection molding.

[0057] The insulating member 116 and the liquid injection hole 113 are spaced apart from each other in the first direction.

[0058] Since the top surface 123 of the cover body 111 is relatively flat, the electrolyte easily overflows during the process of injecting the electrolyte through the injection hole 113 and flows on the top surface 123 , thereby contaminating the insulating member 116 , causing the insulating performance of the insulating member 116 to deteriorate.

[0059] In order to reduce the probability of the electrolyte contaminating the insulating part 116, the following embodiments of the present application, based on the relevant technology, are further provided with a blocking portion. The blocking portion is integrally formed on the cover body 111 through a stamping process, so that a bulge or depression is formed on the surface of the cover body 111 facing away from the accommodating cavity. At least a portion of the blocking portion is located between the injection hole 113 and the insulating part 116 in the first direction X to prevent the electrolyte from spreading from the injection hole 113 to the insulating part 116, thereby reducing the probability of the electrolyte at the injection hole 113 contaminating the insulating part 116. In addition, the blocking portion is integrally formed on the cover body 111 through a stamping process, which, on the one hand, ensures the airtightness of the connection between the blocking portion and the cover body 111, and on the other hand, the manufacturing process is mature and the manufacturing cost is low.

[0060] Various embodiments of the cover plate assembly 103 of the present application are described in detail below.

[0061] Please refer to Figures 3, 4, and 5. Figure 3 is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application. Figure 4 is a top view (partial) of the cover assembly 103 shown in Figure 3. Figure 5 is a cross-sectional view (partial) of the cover assembly 103 shown in Figure 3.

[0062] In some embodiments, the liquid injection hole 113 includes a recessed groove 1131 and a through-hole 1132. The recessed groove 1131 is located on the top surface 123 of the cover body 111. The recessed groove 1131 is circular with a diameter of D1 mm. The through-hole 1132 is located at the center of the recessed groove 1131 and extends through the cover body 111. The through-hole 1132 is a circular hole. The outer diameter of the liquid injection hole 113 is D1 mm.

[0063] In some other embodiments, the liquid injection hole 113 does not have the sink 1131 , that is, the liquid injection hole 113 is a through hole.

[0064] In some embodiments, the injection hole 113 is a rectangular opening, an elliptical opening or an opening of other irregular shapes. When the injection hole 113 is a non-circular shape, the outer diameter of the injection hole 113 is the diameter of the circumscribed circle.

[0065] The specific shape of the liquid injection hole 113 is not limited, as long as it can allow the electrolyte to enter the accommodating cavity.

[0066] In some embodiments, the blocking portion 125 is integrally formed on the cover body 111 by a stamping process, so that a bulge is formed on the top surface 123 of the cover body 111. Specifically, the blocking portion 125 is formed by drawing a portion of the cover body 111. When viewed from the bottom side of the cover body 111, the blocking portion 125 is concave. When viewed from the top surface 123 side of the cover body 111, the blocking portion 125 is a bulge. The blocking portion 125 is arranged outside the liquid injection hole 113. Specifically, the blocking portion 125 is a closed ring. In the illustrated embodiment, the blocking portion 125 is in the shape of a circular ring. Alternatively, the blocking portion 125 may also be in the shape of an ellipse, a rectangular frame, or an irregular pattern.

[0067] When the barrier portion 125 is annular, in some embodiments, the outer diameter of the barrier portion 125 is D2 mm, and the inner diameter of the barrier portion 125 is D3 mm, satisfying the following relationship: (D3-D2) / 2≥2. In some embodiments, the value of (D3-D2) / 2 is 2.5, 3.6, or 4.

[0068] If the blocking portion 125 is annular, in some embodiments, the dimension of the cover body 111 at the blocking portion 125 in the second direction Y is L2 mm, where the second direction Y is perpendicular to the first direction X, satisfying the following relationship: (L2 - D2) / 2 ≥ 2. In other words, the minimum distance L1 between the blocking portion 125 and the edge of the cover body 111 is no less than 2 mm. In some embodiments, L1 is 3, 5, or 6.

[0069] When the barrier 125 is annular, in some embodiments, the minimum distance between the first barrier 125 and the edge of the injection hole 113 is L3 mm, satisfying the following relationship: 2≤L3≤25. In some embodiments, L3 is 2, 5, or 7.

[0070] Because the blocking portion 125 is in a closed ring shape, even if some electrolyte overflows from the injection hole 113, it will be stored in the space enclosed by the blocking portion 125 and eventually injected into the accommodating cavity through the injection hole 113. Therefore, if the amount of electrolyte overflowing from the injection hole 113 is less than a predetermined value, it will not contaminate the insulating member 116 or the cover body 111.

[0071] When the amount of electrolyte overflowing from the injection hole 113 exceeds a predetermined value, the electrolyte will still overflow from the space enclosed by the blocking portion 125. To this end, a notch (not shown) can be provided at the top of the blocking portion 125 (the end facing away from the top surface 123). The notch is located on the side of the blocking portion 125 facing away from the insulating member 116 in the first direction X. The notch guides the electrolyte overflowing from the space enclosed by the blocking portion 125 toward the side facing away from the insulating member 116. This further reduces the probability of the electrolyte at the injection hole 113 contaminating the insulating member 116.

[0072] Please refer to Figures 6 and 7. Figure 6 is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application. Figure 7 is a top view (partial) of the cover assembly 103 shown in Figure 6.

[0073] The following focuses on the differences between the embodiment shown in FIG5 and the embodiment shown in FIG3 .

[0074] In some embodiments, the blocking portion 125 is annular with an opening 127 , and the opening 127 is located on a side of the blocking portion 125 away from the insulating member 116 in the first direction X. The blocking portion 125 is generally C-shaped.

[0075] In this embodiment, the electrolyte overflowing from the injection hole 113 flows toward the side away from the insulating member 116 under the guidance of the opening 127 , thereby reducing the probability of the electrolyte at the injection hole 113 contaminating the insulating member 116 .

[0076] When the blocking portion 125 is C-shaped, in some embodiments, the outer diameter of the blocking portion 125 is D2 mm, and the inner diameter of the blocking portion 125 is D3 mm, satisfying the following relationship: (D3-D2) / 2≥2. In some embodiments, the value of (D3-D2) / 2 is 2.5, 3.6, or 4.

[0077] When the blocking portion 125 is C-shaped, the dimension of the cover body 111 at the blocking portion 125 in the second direction Y is L2 mm. The second direction Y is perpendicular to the first direction X, satisfying the following relationship: (L3 - D2) / 2 ≥ 2. In other words, the minimum distance L1 between the blocking portion 125 and the edge of the cover body 111 is no less than 2 mm. In some embodiments, L1 is 3, 5, or 6.

[0078] When the blocking portion 125 is in a “C” shape, in some embodiments, the dimension of the opening 127 in the second direction Y is L4 mm, satisfying the following relationship: 0<L4≤D3.

[0079] When the blocking portion 125 is C-shaped, in some embodiments, the minimum distance between the first blocking portion 125 and the edge of the injection hole 113 is L3 mm, satisfying the following relationship: 2≤L3≤25. In some embodiments, the value of L3 is 2, 5, or 7.

[0080] Please refer to Figure 8. Figure 8 is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application.

[0081] The following focuses on the differences between the embodiment shown in FIG. 8 and the embodiment shown in FIG. 3 .

[0082] In some embodiments, the blocking portion 125 is in an elongated shape and extends in a second direction Y intersecting the first direction X. Specifically, the second direction Y is perpendicular to the first direction X. The elongated shape of the blocking portion 125 makes the stamping die easier to manufacture.

[0083] In this embodiment, the electrolyte overflowing from the injection hole 113 encounters the blocking portion 125 while spreading on the top surface 123, and will not continue to spread toward the side of the insulating member 116, thereby reducing the probability of the electrolyte at the injection hole 113 contaminating the insulating member 116.

[0084] When the barrier portion 125 is in the shape of an elongated strip, in some embodiments, the minimum distance between the first barrier portion 125 and the edge of the liquid injection hole 113 is L3 mm (see FIG. 16 ), satisfying the following relationship: 2≤L3≤25. In some embodiments, L3 is 2, 10, or 25.

[0085] Please refer to Figures 9 to 12. Figures 9 to 12 are top views of different embodiments of the cover assembly 103 of the present application.

[0086] In some embodiments, the first blocking portion 125 is wavy in shape and protrudes alternately toward the insulating member 116 and the liquid injection hole 113 along the extension path.

[0087] In some embodiments, the first blocking portion 125 is V-shaped and protrudes toward the insulating member 116 or the liquid injection hole 113 along the extension path.

[0088] The specific shape of the blocking portion 125 is not limited to the above examples. As long as the blocking portion 125 can prevent the electrolyte from spreading on the top surface 123 , the specific shape of the blocking portion 125 can be set according to specific needs.

[0089] Please refer to Figure 13. Figure 13 is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application.

[0090] In some embodiments, the blocking portion 125 is integrally formed on the cover body 111 by a stamping process, so that the top surface 123 of the cover body 111 forms a depression. Specifically, the blocking portion 125 is formed by drawing a portion of the cover body 111. When viewed from the bottom surface of the cover body 111, the blocking portion 125 is a convex portion. When viewed from the top surface 123 of the cover body 111, the blocking portion 125 is a concave portion. At least a portion of the blocking portion 125 is located between the injection hole 113 and the insulating member 116 in the first direction X to prevent the electrolyte from spreading from the injection hole 113 to the insulating member 116.

[0091] 13 , the blocking portion 125 is in the shape of an elongated strip and extends in a second direction Y intersecting the first direction X. Specifically, the second direction Y is perpendicular to the first direction X.

[0092] The electrolyte overflowing from the injection hole 113 spreads along the top surface 123. Upon encountering the barrier 125, the electrolyte enters the recess formed by the barrier 125, thereby stopping the spread. In some embodiments, the electrolyte in the recess gradually evaporates. In other embodiments, the electrolyte in the recess can also be actively cleaned.

[0093] When the blocking portion 125 forms a depression on the top surface 123 of the cover body 111 , the specific shape of the blocking portion 125 is not limited to a strip, but may also be the shape of the above embodiments, for example, a circular ring, a "C" shape, a wavy shape, or a "V" shape.

[0094] Please refer to Figure 14. Figure 14 is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application.

[0095] In some embodiments, the cover plate assembly 103 includes a blocking portion 125a and a blocking portion 125b. The blocking portion 125a and the blocking portion 125b are both integrally formed on the cover body 111 through a stamping process. Among them, one of the blocking portion 125a and the blocking portion 125b forms a convexity on the top surface 123 of the cover body 111, and the other of the blocking portion 125a and the blocking portion 125b forms a concaveity on the top surface 123 of the cover body 111. In the embodiment shown in Figure 14, the blocking portion 125a forms a convexity on the top surface 123 of the cover body 111, and the blocking portion 125b forms a concaveity on the top surface 123 of the cover body 111. In other embodiments, the blocking portion 125a may form a concaveity on the top surface 123 of the cover body 111, and the blocking portion 125b may form a convexity on the top surface 123 of the cover body 111.

[0096] This arrangement further reduces the probability of electrolyte contamination of the insulating member 116. Furthermore, the blocking portion 125a and the blocking portion 125b are adjacently positioned and integrally formed into the cover body 111 via a stamping process, with the two portions drawn in opposite directions. Both blocking portions 125a and 125b can be formed simultaneously during a single stamping operation. During the stamping process, the forces acting on the cover body 111 are balanced, making it easier to ensure dimensional accuracy.

[0097] When one of the blocking portion 125a and the blocking portion 125b forms a convexity on the top surface 123 of the cover body 111, and the other of the blocking portion 125a and the blocking portion 125b forms a concaveity on the top surface 123 of the cover body 111, the specific shape of the blocking portion 125a or the blocking portion 125b can be the shape in the above-mentioned embodiments, for example, a circular ring shape, a "C" shape, a wavy shape, or a "V" shape.

[0098] Please refer to Figure 15. Figure 15 is a side view of an embodiment of the cover assembly 103 of the present application.

[0099] The maximum size of the secondary battery in the third direction Z is determined by the height of the terminal 115 protruding from the top surface 123. The third direction Z is perpendicular to the first direction X and the second direction Y.

[0100] In the embodiment where the blocking portion 125 is formed as a protrusion on the top surface 123 of the cover body 111 , in order to prevent the blocking portion 125 from affecting the maximum size of the secondary battery in the third direction Z, the following limitations are further imposed.

[0101] The blocking portion 125 protrudes from the top surface 123 by a height H1 , and the pole 115 protrudes from the top surface 123 by a height H2 , satisfying the following relationship: H1 ≤ H2 .

[0102] In some embodiments, the secondary battery further includes a cover patch (not shown), which is attached to at least the surface of the barrier portion 125 facing away from the cover body 111. Specifically, the cover patch can be attached to the top surface 123 of the cover body 111 and cover the barrier portion 125 using a blister process, and does not cover the terminal 115. The thickness of the cover patch is T2. Correspondingly, the following relationship is satisfied: H1 + T2 ≤ H2.

[0103] Please refer to Figure 16. Figure 16 is a top view of an embodiment of the cover assembly 103 of the present application.

[0104] The blocking portion 125 and the edge of the cover body 111 have a minimum spacing L1 in the second direction Y, and the second direction Y is perpendicular to the first direction X. The smaller the minimum spacing L1, the better the blocking effect of the blocking portion 125 in the first direction X. However, since the blocking portion 125 is formed by a stamping process, the smaller the minimum spacing L1, the greater the manufacturing difficulty. For example, it may cause deformation of the edge of the cover body 111. In addition, in some embodiments, the secondary battery needs to be coated with an insulating film (not shown), and the insulating film is closed at the top surface 123 of the cover body 111. The smaller the minimum spacing L1, the more difficult it is to coat the insulating film. For example, the probability of the insulating film warping at the closing point may increase.

[0105] To this end, it is necessary to reasonably set the size range of the minimum spacing L1 to satisfy the following relationship:

[0106] 0.1*T1+1.8≤L1≤D1 / 4+1.75, where L2≤15;

[0107] 0.1*T1+1.8≤L1≤L2 / 4, where L2>15.

[0108] In the relationship, T1 is the thickness of the cover body 111, in mm; D1 is the outer diameter of the injection hole 113, in mm; L2 is the dimension of the cover body 111 at the blocking portion 125 in the second direction Y, in mm.

[0109] In some embodiments, the minimum distance between the first blocking portion 125 and the edge of the cover body 111 is L1 mm, and the dimension of the cover body 111 at the first blocking portion 125 perpendicular to the first direction X is L2 mm, satisfying the following relationship:

[0110] 2≤L1≤3.75, where L2≤15;

[0111] 2≤L1≤L2 / 4, where L2>15.

[0112] In order to verify the rationality of the size range of the minimum spacing L1, the following comparative tests were conducted:

[0113] The following comparative tests were conducted using secondary batteries incorporating the cap plate assemblies shown in Figures 3, 8, and 14, respectively. The test results for the secondary battery incorporating the cap plate assembly shown in Figure 3 are shown in Table 1. The test results for the secondary battery incorporating the cap plate assembly shown in Figure 8 are shown in Table 2. The test results for the secondary battery incorporating the cap plate assembly shown in Figure 14 are shown in Table 1.

[0114] The following examples and comparative examples all share the same structure. Thirty secondary battery samples were selected for each example and comparative example. Each sample was injected with electrolyte and coated with an insulating film. The pass rate of the insulating film coating and the probability of uncontaminated insulating components were calculated for each example and comparative example.

[0115] Table 1:

[0116] Table 2:

[0117] Table 3:

[0118] As can be seen from the above table, in the embodiment of the present application, by limiting the size range of the minimum spacing L1, the probability of the insulating part 116 being contaminated can be reduced while ensuring that it can be stamped and formed, and the success rate of the insulating film coating can be improved.

[0119] In summary, the secondary battery and the cover plate assembly thereof provided in the embodiments of the present application can reduce the probability of the electrolyte at the injection hole being contaminated with the insulating component.

[0120] The first blocking portion is integrally formed with the cover body 111 through a stamping process, forming a protrusion or depression on the surface of the cover body 111 facing away from the accommodating cavity. At least a portion of the first blocking portion is located between the liquid injection hole 113 and the insulating member 116 in the first direction, thereby preventing the electrolyte from spreading from the liquid injection hole 113 to the insulating member 116. This reduces the probability of electrolyte contamination from the liquid injection hole 113 to the insulating member 116. Furthermore, the first blocking portion is integrally formed with the cover body 111 through a stamping process, which not only ensures the airtightness of the connection between the first blocking portion and the cover body 111, but also enables a mature manufacturing process and low manufacturing costs.

[0121] The above steps are merely provided to help understand the method, structure, and core concept of the present application. A person skilled in the art may make several improvements and modifications to the present application without departing from the principles of the present application, and such improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A cover plate assembly for a secondary battery, comprising: A cover body, the cover body being configured to cover the opening of the shell of the secondary battery so as to be surrounded by the shell to form a receiving cavity, the cover body having a liquid injection hole, the liquid injection hole being communicated with the receiving cavity so as to inject electrolyte into the receiving cavity through the liquid injection hole; A pole, the pole is passed through the cover body, a part of the pole is located outside the accommodating cavity, and the other part is located inside the accommodating cavity; an insulating member, the insulating member being sandwiched between the pole and the cover body so as to electrically insulate the pole from the cover body, the insulating member and the liquid injection hole being spaced apart in a first direction; The first blocking portion is integrally formed on the cover body by a stamping process so that a bulge or a depression is formed on the surface of the cover body facing away from the accommodating cavity, and at least a portion of the first blocking portion is located between the injection hole and the insulating member in the first direction to prevent the electrolyte from spreading from the injection hole to the insulating member.

2. The cover plate assembly according to claim 1, wherein: The first blocking portion is disposed outside the liquid injection hole.

3. The cover plate assembly according to claim 2, wherein: The first blocking portion is in a closed ring shape.

4. The cover plate assembly according to claim 2 or 3, wherein: The first blocking portion is in a ring shape with an opening, and the opening is located on a side of the first blocking portion away from the insulating member in the first direction.

5. The cover plate assembly according to claim 1, wherein: The first blocking portion extends in a second direction intersecting the first direction.

6. The cover plate assembly according to claim 5, wherein: The first blocking portion is in any of a strip shape, a wave shape, and a "V" shape; When the first blocking portion is wavy, it protrudes toward the insulating member and the liquid injection hole alternately along the extension path; When the first blocking portion is in a "V" shape, it protrudes toward the insulating member or the injection hole on the extension path.

7. The cover plate assembly according to claim 1, further comprising: The second blocking portion is integrally formed on the cover body by a stamping process so that A convexity or a concave is formed on a surface of the cover body facing away from the accommodating cavity, and at least a portion of the second blocking portion is located between the injection hole and the insulating member in the first direction to prevent the electrolyte from spreading from the injection hole to the insulating member; Among them, one of the first blocking portion and the second blocking portion forms a bulge on the surface of the cover body facing away from the accommodating cavity, and the other of the first blocking portion and the second blocking portion forms a depression on the surface of the cover body facing away from the accommodating cavity.

8. The cover plate assembly according to claim 1, wherein: The minimum distance between the first blocking portion and the edge of the cover body is L1 mm, the cover body is in the shape of a flat plate, the thickness of the cover body is T1 mm, the dimension of the cover body at the first blocking portion perpendicular to the first direction is L2 mm, and the outer diameter of the injection hole is D1 mm, satisfying the following relationship: 0.1*T1+1.8≤L1≤D1 / 4+1.75, where L2≤15; 0.1*T1+1.8≤L1≤L2 / 4, where L2>15.

9. The cover plate assembly according to claim 1, wherein: The minimum distance between the first blocking portion and the edge of the cover body is L1 mm, and the dimension of the cover body at the first blocking portion perpendicular to the first direction is L2 mm, satisfying the following relationship: 2≤L1≤3.75, where L2≤15; 2≤L1≤L2 / 4, where L2>15.

10. The cover plate assembly according to claim 1, wherein: The minimum distance between the first blocking portion and the edge of the liquid injection hole is L3 mm, satisfying the following relationship: 2≤L3≤25.

11. The cover plate assembly according to claim 1, wherein: When the first blocking portion causes the cover body to bulge on the side facing away from the accommodating cavity, the protruding height of the first blocking portion is H1, and the height of the pole protruding from the cover body on the side facing away from the accommodating cavity is H2, satisfying the following relationship: H1≤H2.

12. The cover plate assembly according to claim 11, wherein: The cover plate assembly further includes a cover plate patch, which is at least attached to a surface of the first blocking portion on a side facing away from the cover body. The thickness of the cover plate patch is T2, satisfying the following relationship: H1+T2≤H2.

13. A secondary battery comprising: A housing, one side of which has an opening; A cover plate assembly, the cover plate assembly is arranged to cover the opening of the shell and is surrounded by the shell to form a receiving cavity; An electrode assembly, wherein the electrode assembly is accommodated in the accommodation cavity; Wherein, the cover plate assembly is the cover plate assembly according to any one of claims 1 to 12.

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