Secondary battery and cover assembly thereof

Abstract

The embodiment of the present application discloses a secondary battery and its cover assembly, which includes a cover body, a pole, an insulating member and a first blocking portion. The cover body is used to seal the opening of the shell of the secondary battery, and the cover body has a liquid injection hole; the insulating member is sandwiched between the pole and the cover body to electrically insulate the pole and the cover body, and the insulating member and the liquid injection hole are spaced apart in the first direction; the first blocking portion is integrally formed on the cover body by a stamping process, so that a convexity or a concave is formed on the surface of the cover body facing away from the accommodating cavity, and at least part of the first blocking portion is located between the liquid injection hole and the insulating member in the first direction to prevent the electrolyte from spreading from the liquid injection hole to the insulating member. The embodiment of the present application reduces the probability of the electrolyte at the liquid injection hole contaminating the insulating member.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a secondary battery and a cover plate assembly thereof. Background Art

[0002] 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.

[0003] The cover assembly of the secondary battery is an accessory in the secondary battery. One function is to form a containing cavity isolated from the outside after welding with the shell, and the other function is to connect the internal and external circuits to transmit the internal current of the secondary battery to the outside.

[0004] The cover plate assembly includes a plain aluminum plate, a pole and an insulating member. The insulating member is arranged between the pole and the plain aluminum plate to achieve electrical insulation. The plain aluminum plate is provided with a liquid injection hole. When the electrolyte is injected through the liquid injection hole, the electrolyte easily overflows to the insulating member, resulting in a reduction in the insulation effect of the insulating member. Summary of the invention

[0005] The embodiments of the present application provide a secondary battery and a cover plate assembly thereof, which reduce the probability of electrolyte at a liquid injection hole contaminating an insulating member.

[0006] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:

[0007] On the one hand, a cover plate assembly of a secondary battery is provided, comprising a cover body, a pole, an insulating member and a first blocking portion. The cover body is used to cover the opening of the shell of the secondary battery to form a receiving cavity with the shell, and the cover body has a liquid injection hole, which is connected to the receiving cavity so that electrolyte is injected into the receiving cavity through the liquid injection hole; the pole is passed through the cover body, with one part located outside the receiving cavity and the other part located inside the receiving cavity; the insulating member is sandwiched between the pole and the cover body so that the pole is electrically insulated from the cover body, and the insulating member and the liquid injection hole are spaced apart in a first direction; the first blocking portion is integrally formed on the cover body by a stamping process so that a convexity or a concave is formed on the surface of the cover body on the side facing away from the receiving cavity, and at least a part of the first blocking portion is located between the liquid injection hole and the insulating member in the first direction to prevent the electrolyte from spreading from the liquid injection hole to the insulating member.

[0008] In addition to or as an alternative to one or more of the features disclosed above, the first blocking portion is arranged outside the liquid injection hole.

[0009] In addition to or as an alternative to one or more features disclosed above, 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] In addition to one or more of the features disclosed above, or as an alternative, the first blocking portion is in the shape of an elongated strip, extending in a second direction intersecting the first direction, 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] In addition to one or more of the features disclosed above, or as an alternative, the cover plate assembly also includes a second blocking portion, which is integrally formed on the cover body through a stamping process so that a protrusion 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 a 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 protrusion 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] In addition to one or more of the features disclosed above, or as an alternative, the minimum spacing 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 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] In addition to one or more features disclosed above, or as an alternative, the minimum spacing 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] In addition to or as an alternative to one or more of the features disclosed above, 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] In addition to one or more of the above-disclosed features, or as an alternative, 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 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, and a thickness of the cover plate patch is T2, satisfying the following relationship: H1+T2≤H2.

[0021] On the other hand, the present application also provides a secondary battery, comprising a shell, a cover assembly and an electrode assembly. One side of the shell has an opening; the cover assembly covers the opening of the shell and is surrounded by the shell to form a receiving cavity; the electrode assembly is received in the receiving cavity; wherein the cover assembly is any of the above-mentioned cover assemblies.

[0022] One of the above technical solutions has the following advantages or beneficial effects:

[0023] The first blocking portion is integrally formed on the cover body by a stamping process, so that a bulge or 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. Thus, the probability of the electrolyte at the injection hole contaminating the insulating member is reduced. In addition, the first blocking portion is integrally formed on the cover body by a stamping process, which, on the one hand, ensures the airtightness of the connection between the first blocking portion and the cover body, and on the other hand, the manufacturing process is mature and the manufacturing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0025] Figure 1 is a three-dimensional exploded view of an embodiment of a secondary battery of the present application;

[0026] Figure 2 It is a three-dimensional structural schematic diagram of a cover plate assembly in the related art;

[0027] Figure 3 It is a three-dimensional structural schematic diagram of an embodiment of a cover plate assembly of the present application;

[0028] Figure 4 yes Figure 3 A top view (partial) of the cover assembly shown;

[0029] Figure 5 yes Figure 3 A sectional view (partial) of the cover assembly shown;

[0030] Figure 6 It is a three-dimensional structural schematic diagram of an embodiment of a cover plate assembly of the present application;

[0031] Figure 7 yes Figure 6 A top view (partial) of the cover assembly shown;

[0032] Figure 8 It is a three-dimensional structural schematic diagram of an embodiment of a cover plate assembly of the present application;

[0033] Fig. 9 is a top view of an embodiment of a cover plate assembly of the present application;

[0034] Fig.10 is a top view of an embodiment of a cover plate assembly of the present application;

[0035] Fig.11 is a top view of an embodiment of a cover plate assembly of the present application;

[0036] Fig.12 is a top view of an embodiment of a cover plate assembly of the present application;

[0037] Fig.13 It is a three-dimensional structural schematic diagram of an embodiment of a cover plate assembly of the present application;

[0038] Fig.14 It is a three-dimensional structural schematic diagram of an embodiment of a cover plate assembly of the present application;

[0039] Fig.15 is a side view of an embodiment of a cover plate assembly of the present application;

[0040] Fig.16 It is a top view of an embodiment of a cover plate assembly of the present application.

[0041] 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

[0042] In order to make the purpose, technical solution and beneficial effects of this application more clear, the following further describes this application in detail in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described in this specification are only for explaining this application, not for limiting this application.

[0043] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" refers to two or more, unless otherwise clearly and specifically defined.

[0044] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0045] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0046] A secondary battery is a battery that can be recharged to activate the active materials after being discharged and continue to be used.

[0047] Generally, a secondary battery includes a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet to play a role of isolation. The electrolyte plays a role of conducting ions between the positive electrode sheet and the negative electrode sheet.

[0048] See also Figure 1 . Figure 1 It is a three-dimensional exploded view of an embodiment of a secondary battery of the present application.

[0049] In some embodiments, the secondary battery includes a housing 101, a cover assembly 103 (two in the figure), and an electrode assembly 105. One side of the housing 101 has an opening. The cover assembly 103 covers the opening of the housing 101 and is surrounded by the housing 101 to form a receiving cavity. The electrode assembly 105 is received in the receiving cavity.

[0050] Specifically, Figure 1 In the illustrated embodiment, the housing 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 housing 101, and are surrounded to form a receiving cavity. The receiving cavity also contains an electrolyte. The electrode assembly 105 includes the above-mentioned positive electrode sheet, negative electrode sheet, and separator. In some embodiments, the electrode assembly 105 is wound by the positive electrode sheet, the negative electrode sheet, and the separator. In other embodiments, the electrode assembly 105 is stacked by the positive electrode sheet, the negative electrode sheet, and the separator. In order to insulate the electrode assembly 105 from the housing 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 housing 101 is also provided with an explosion-proof valve 109 to release the high-pressure gas in the receiving cavity when the secondary battery is thermally runaway.

[0051] In some other embodiments, the secondary battery may also be a conventional square battery, that is, the housing 101 has an opening on only one side and has only one cover assembly 103 .

[0052] 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 .

[0053] See also Figure 2 . Figure 2 It is a schematic diagram of the three-dimensional structure of the cover plate assembly 103 in the related art.

[0054] In the related art, the cover plate assembly 103 includes a cover body 111 , a pole 115 , an insulating member 116 and a lower plastic 121 .

[0055] The cover body 111 is used to cover the opening of the shell 101 of the secondary battery, so as to form a receiving cavity with the shell 101. Specifically, the cover body 111 is generally in the shape of a plate. The material of the cover body 111 can be aluminum or aluminum alloy. The cover body 111 and the shell 101 can be laser welded.

[0056] 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.

[0057] 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 .

[0058] The cover body 111 has a liquid injection hole 113. The liquid injection hole 113 penetrates the cover body 111 in the spacing direction between the top surface 123 and the bottom surface. The liquid injection hole 113 is connected to the accommodating cavity so that electrolyte is injected into the accommodating cavity through the liquid injection hole 113.

[0059] The pole 115 is provided through the cover body 111, with a portion located outside the accommodating cavity and another portion located inside the accommodating cavity. Specifically, the pole 115 includes a conductor 117 and a rivet 119. The conductor 117 is provided through the cover body 111, with a portion located outside the accommodating cavity and another portion located inside the accommodating cavity. The rivet 119 is riveted to the portion of the conductor 117 located outside the accommodating cavity. Among them, the portion of the conductor 117 located inside the accommodating cavity is electrically connected to the electrode assembly 105.

[0060] 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.

[0061] The insulating member 116 and the liquid injection hole 113 are spaced apart from each other in the first direction.

[0062] Since the top surface 123 of the cover body 111 is relatively flat, during the process of injecting electrolyte through the injection hole 113 , the electrolyte easily overflows and flows on the top surface 123 , thereby contaminating the insulating member 116 , causing the insulating performance of the insulating member 116 to decrease.

[0063] In order to reduce the probability of the electrolyte contaminating the insulating member 116, the following embodiments of the present application, on the basis of the relevant technology, are further provided with a blocking portion. The blocking portion is integrally formed on the cover body 111 by a stamping process, so that a bulge or a depression is formed on the surface of the cover body 111 facing away from the accommodating cavity. At least part of the blocking portion is located between the injection hole 113 and the insulating member 116 in the first direction X to block the electrolyte from spreading from the injection hole 113 to the insulating member 116, thereby reducing the probability of the electrolyte at the injection hole 113 contaminating the insulating member 116. In addition, the blocking portion is integrally formed on the cover body 111 by 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.

[0064] Various embodiments of the cover plate assembly 103 of the present application are described in detail below.

[0065] See also Figure 3 , Figure 4 as well as Figure 5 . Figure 3 It is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application. Figure 4 yes Figure 3 A top view (partial) of the cover plate assembly 103 is shown. Figure 5 yes Figure 3 A cross-sectional view (partial) of the cover plate assembly 103 is shown.

[0066] In some embodiments, the injection hole 113 includes a sink 1131 and a through hole 1132. The sink 1131 is located on the top surface 123 of the cover body 111. The sink 1131 is circular with a diameter of D1 mm. The through hole 1132 is located at the center of the sink 1131 and penetrates the cover body 111. The through hole 1132 is a circular hole. The outer diameter of the injection hole 113 is D1 mm.

[0067] In some other embodiments, the injection hole 113 does not have the sink 1131 , that is, the injection hole 113 is a through hole.

[0068] 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.

[0069] The specific shape of the injection hole 113 is not limited, as long as it can allow the electrolyte to enter the accommodating cavity.

[0070] 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. Observing from the bottom surface of the cover body 111, the blocking portion 125 is concave. Observing from the top surface 123 of the cover body 111, the blocking portion 125 is a bulge. The blocking portion 125 is arranged outside the 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.

[0071] When the blocking portion 125 is in a circular ring shape, 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.

[0072] When the blocking portion 125 is in a circular ring shape, in some embodiments, the size of the cover body 111 at the blocking portion 125 in the second direction Y is L2 mm, and the second direction Y is perpendicular to the first direction X, satisfying the following relationship: (L2-D2) / 2≥2. That is, the minimum spacing L1 between the blocking portion 125 and the edge of the cover body 111 is not less than 2 mm. In some embodiments, the value of L1 is 3, 5 or 6.

[0073] When the blocking portion 125 is annular, 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.

[0074] Since the blocking portion 125 is a closed ring, even if part of the electrolyte overflows from the injection hole 113, it will be stored in the space surrounded by the blocking portion 125 and finally injected into the accommodating cavity through the injection hole 113. Therefore, when the amount of electrolyte overflowing from the injection hole 113 is less than a predetermined value, it will not contaminate not only the insulating member 116 but also the cover body 111.

[0075] When the amount of electrolyte overflowing from the injection hole 113 is greater than 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 also be provided at the top of the blocking portion 125 (the end away from the top surface 123), and the notch is located on the side of the blocking portion 125 away from the insulating member 116 in the first direction X. The electrolyte overflowing from the space enclosed by the blocking portion 125 is guided by the notch to flow toward the side away from the insulating member 116. As a result, the probability of the electrolyte at the injection hole 113 contaminating the insulating member 116 is further reduced.

[0076] See also Figure 6 and Figure 7 . Figure 6 It is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application. Figure 7 yes Figure 6 A top view (partial) of the cover plate assembly 103 is shown.

[0077] The following focuses on Figure 5 The embodiment shown and Figure 3 The embodiments shown are different.

[0078] 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 substantially in a “C” shape.

[0079] 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 .

[0080] When the blocking portion 125 is in a "C" shape, 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.

[0081] When the blocking portion 125 is in a "C" shape, the size of the cover body 111 at the blocking portion 125 in the second direction Y is L2 mm, and the second direction Y is perpendicular to the first direction X, satisfying the following relationship: (L3-D2) / 2≥2. That is, the minimum spacing L1 between the blocking portion 125 and the edge of the cover body 111 is not less than 2 mm. In some embodiments, the value of L1 is 3, 5 or 6.

[0082] When the blocking portion 125 is in a “C” shape, in some embodiments, the size of the opening 127 in the second direction Y is L4 mm, satisfying the following relationship: 0<L4≤D3.

[0083] When the blocking portion 125 is in a "C" shape, 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.

[0084] See also Figure 8 . Figure 8 It is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application.

[0085] The following focuses on Figure 8 The embodiment shown and Figure 3 The embodiments shown are different.

[0086] In some embodiments, 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. The blocking portion 125 is in the shape of an elongated strip, so that the stamping die is easier to manufacture.

[0087] In this embodiment, the electrolyte overflowing from the injection hole 113 encounters the obstruction of the blocking portion 125 when 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.

[0088] In the case where the blocking portion 125 is in the shape of an elongated strip, in some embodiments, the minimum distance between the first blocking portion 125 and the edge of the injection hole 113 is L3 mm (see Fig.16 ), satisfying the following relationship: 2≤L3≤25. In some embodiments, the value of L3 is 2, 10 or 25.

[0089] See also Figures 9 to 12 . Figures 9 to 12 They are respectively top views of different embodiments of the cover assembly 103 of the present application.

[0090] In some embodiments, the first blocking portion 125 is wavy in shape and protrudes toward the insulating member 116 and the injection hole 113 alternately along the extension path.

[0091] In some embodiments, the first blocking portion 125 is in a “V” shape and protrudes toward the insulating member 116 or the injection hole 113 on the extension path.

[0092] 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.

[0093] See also Fig.13 . Fig.13 It is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application.

[0094] 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 side of the cover body 111, the blocking portion 125 is a convexity. When viewed from the top surface 123 side of the cover body 111, the blocking portion 125 is a depression. 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.

[0095] Fig.13 In the illustrated embodiment, the blocking portion 125 is in the shape of an elongated strip, and extends in a second direction Y intersecting with the first direction X. Specifically, the second direction Y is perpendicular to the first direction X.

[0096] The electrolyte overflowing from the injection hole 113 spreads on the top surface 123, encounters the blocking portion 125, and enters the depression formed by the blocking portion 125, thereby stopping spreading. In some embodiments, the electrolyte in the depression will gradually evaporate. In other embodiments, the electrolyte in the depression can also be actively cleaned.

[0097] When the blocking portion 125 causes the top surface 123 of the cover body 111 to form a depression, the specific shape of the blocking portion 125 is not limited to a long 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.

[0098] See also Fig.14 . Fig.14 It is a schematic diagram of the three-dimensional structure of an embodiment of the cover assembly 103 of the present application.

[0099] 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 integrally formed on the cover body 111 through a stamping process. 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 concave on the top surface 123 of the cover body 111. Fig.14 In the illustrated embodiment, 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.

[0100] Such an arrangement can further reduce the probability of electrolyte contaminating the insulating member 116. In addition, the blocking portion 125a and the blocking portion 125b are arranged adjacent to each other and are integrally formed on the cover body 111 by a stamping process, and the two are drawn in opposite directions. The blocking portion 125a and the blocking portion 125b can be formed simultaneously during a single stamping operation. During the stamping process, the force on the cover body 111 is balanced, and it is easier to ensure dimensional accuracy.

[0101] 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.

[0102] See also Fig.15 . Fig.15 It is a side view of an embodiment of the cover assembly 103 of the present application.

[0103] Generally, the maximum size of the secondary battery in the third direction Z is determined by the height of the pole 115 protruding from the top surface 123. The third direction Z is perpendicular to the first direction X and the second direction Y, respectively.

[0104] 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 definition is further made.

[0105] 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 .

[0106] In some embodiments, the secondary battery further includes a cover patch (not shown), which is at least attached to the surface of the blocking portion 125 on the side 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 the blocking portion 125 by a blister process, and the cover patch does not cover the pole 115. The thickness of the cover patch is T2. Correspondingly, the following relationship is satisfied: H1+T2≤H2.

[0107] See also Fig.16 . Fig.16 It is a top view of an embodiment of the cover assembly 103 of the present application.

[0108] 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 greater the difficulty of coating the insulating film, for example, it may cause the probability of the insulating film warping at the closing point to increase.

[0109] To this end, it is necessary to reasonably set the size range of the minimum spacing L1 to satisfy the following relationship:

[0110] 0.1*T1+1.8≤L1≤D1 / 4+1.75, where L2≤15;

[0111] 0.1*T1+1.8≤L1≤L2 / 4, where L2>15.

[0112] 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.

[0113] 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:

[0114] 2≤L1≤3.75, where L2≤15;

[0115] 2≤L1≤L2 / 4, where L2>15.

[0116] In order to verify the rationality of the size range of the minimum spacing L1, the following comparative tests were conducted:

[0117] The following comparative tests were conducted using Figure 3 , Figure 8 as well as Fig.14 The secondary battery with the cap plate assembly shown in FIG. Figure 3 The test results of the secondary battery with the cap assembly shown are shown in Table 1. Figure 8 The test results of the secondary battery with the cap assembly shown are shown in Table 2. Fig.14 The test results of the secondary battery with the cap plate assembly shown are shown in Table 1.

[0118] The other structures of the following embodiments and comparative examples are the same. Thirty samples of the secondary battery in each embodiment and comparative example are selected. Electrolyte and coated insulating film are injected into each sample. The qualified rate of coated insulating film and the probability of uncontaminated insulating parts of each embodiment and comparative example are calculated.

[0119] Table 1.

[0120]

[0121] Table 2:

[0122]

[0123] Table 3:

[0124]

[0125]

[0126] It can be seen from the above table that 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 at the same time, the success rate of coating the insulating film can be improved.

[0127] 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 to the insulating member.

[0128] The introduction provided in the above steps is only used to help understand the method, structure and core idea of ​​the present application. For ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these 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, characterized in that: include: A cover body, the cover body is used to cover the open opening of the shell of the secondary battery to form a receiving cavity with the shell, and the cover body has a liquid injection hole, the liquid injection hole is connected with the receiving cavity, so that electrolyte is injected 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 injection hole being spaced apart in a first direction, the first direction being the length direction of the cover body; A first blocking portion, the first 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 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; 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; A second blocking portion, the second blocking portion is integrally formed on the cover body by a stamping process, so that a convexity or a concaveity 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.

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

3. The cover plate assembly according to claim 2, characterized in that: The first blocking portion is a closed ring; or, 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.

4. The cover plate assembly according to claim 1, characterized in that: The first blocking portion is in the shape of an elongated strip and extends in a second direction intersecting with the first direction. Optionally, the second direction is perpendicular to the first direction; or, The first blocking portion is wavy and protrudes toward the insulating member and the liquid injection hole alternately along the extension path; or, The first blocking portion is in a "V" shape and protrudes toward the insulating member or the injection hole on the extension path.

5. The cover plate assembly according to claim 1, characterized in that: The first blocking part or the second blocking part provided with a protrusion is an annular structure, and the side of the first blocking part or the second blocking part provided with a protrusion away from the cover body has a notch, and the notch is provided on the side of the first blocking part or the second blocking part away from the insulating part in the first direction.

6. The cover plate assembly according to claim 1, characterized in that: 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.

7. The cover plate assembly according to claim 1, characterized in that: 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.

8. The cover plate assembly according to claim 1, characterized in that: When the first blocking portion causes the surface of the cover body facing away from the accommodating cavity to form a bulge, 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; The cover plate assembly further includes a cover plate patch, which is at least attached to a surface of the first blocking portion that faces away from the cover body. The thickness of the cover plate patch is T2, satisfying the following relationship: H1+T2 ≤ H2.

9. A secondary battery, characterized in that: include: 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 8.

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