Battery

Abstract

The invention provides a battery, relates to the technical field of batteries, and is used for solving the problems of high cost and poor sealing performance of a metal shell in the related art, the battery comprises a battery cell, a bottom shell, a sealing cover and a sealing glue layer, the battery cell comprises a battery cell main body and a tab assembly extending from one side of the battery cell main body; the bottom shell is provided with an opening, and the sealing cover covers the opening so that a sealing cavity can be formed in the bottom shell. The battery cell is positioned in the sealing cavity; the sealing cover comprises a body and a side wall extending from the face, close to the bottom shell, of the body, the side wall is arranged around the opening, and a bent structure is arranged at the opening. The bending structure comprises a bending part and a turnup which are connected with each other, the bending part is connected with the edge of the opening, and the bending part and / or the turnup are / is connected with the side wall through a sealant layer; and at least one end of the sealing glue layer exceeds the overlapping area of the bending structure and the side wall. The sealing glue layer is arranged between the bending structure and the sealing cover, so that the cost is reduced, the sealing performance of the battery is improved, and external water vapor is prevented from entering the sealing cavity.

Description

Technical Field

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

[0002] Metal packaged batteries are a type of battery that uses a metal casing as packaging material. The metal casing includes a bottom casing and a sealing cover. The bottom casing and the sealing cover are usually made of aluminum or steel and can provide a sturdy protective structure for the battery.

[0003] In the related art, the sealing cover is welded to the bottom shell by laser welding; however, the laser welding method has high manufacturing cost and often results in welding leaks or cold welds, resulting in poor sealing of the metal shell. Summary of the invention

[0004] In view of the above problems, an embodiment of the present application provides a battery to solve the problems of high manufacturing cost and poor sealing of the metal casing in the related art.

[0005] In order to achieve the above objectives, the present application provides the following technical solutions:

[0006] An embodiment of the present application provides a battery, which includes: the battery cell includes a battery cell body and a pole ear assembly extending from one side of the battery cell body; a bottom shell, the bottom shell has an opening; a sealing cover, the sealing cover is arranged at the opening to form a sealed cavity in the bottom shell, and the battery cell is located in the sealed cavity; the sealing cover includes a main body and a side wall extending from a side of the main body close to the bottom shell, and the side wall is arranged around the opening; a bending structure is arranged at the opening, and the bending structure includes: a connected bending portion and a flange, the bending portion is connected to the edge of the opening, and the bending portion and / or the flange is connected to the side wall through a sealing layer; at least one end of the sealing layer exceeds the overlapping area of ​​the bending structure and the side wall.

[0007] In one embodiment of the present application, the bending portion includes an arc-shaped protrusion, the apex of the arc-shaped protrusion faces the main body, one end of the arc-shaped protrusion is connected to the edge of the opening, the other end of the arc-shaped protrusion is connected to the head end of the flange, and the tail end of the flange extends away from the main body; the intersection of the side wall and the main body has a first arc-shaped corner, one end of the sealant layer overflows from between the arc-shaped protrusion and the first arc-shaped corner, and / or the other end of the sealant layer overflows from between the tail end of the flange and the side wall.

[0008] In one embodiment of the present application, the bending portion includes a first horizontal connecting section and a second arcuate corner and a third arcuate corner arranged at both ends of the first horizontal connecting section, the second arcuate corner is connected to the edge of the opening, the third arcuate corner is connected to the head end of the flange, and the tail end of the flange extends close to the main body; the flange surrounds the outer periphery of the side wall, and one end of the sealant layer overflows from between the tail end of the flange and the side wall.

[0009] In one embodiment of the present application, the bending portion includes a first horizontal connecting section and a second arcuate corner and a third arcuate corner arranged at both ends of the first horizontal connecting section, the second arcuate corner is connected to the edge of the opening, the third arcuate corner is connected to the head end of the flange, and the tail end of the flange extends close to the main body; the side wall surrounds the outer circumference of the flange; the side wall and the main body have a first arcuate corner at the intersection, one end of the sealant layer overflows from between the tail end of the flange and the first arcuate corner, and extends to the main body; and / or the other end of the sealant layer overflows from between the flange and the side wall.

[0010] In one embodiment of the present application, the tail end of the flange is also connected to a second horizontal connecting section arranged opposite to the first horizontal connecting section, the second horizontal connecting section is connected to the main body through the sealant layer, and one end of the sealant layer overflows from between the second horizontal connecting section and the main body.

[0011] In one embodiment of the present application, the end of the side wall away from the main body includes a fastening flange bent toward the sealing cavity, and the fastening flange is in contact with a portion of the first horizontal connecting section.

[0012] In one embodiment of the present application, the bottom shell includes a bottom surface, the bottom surface is opposite to the main body, and a boss protruding toward the main body is arranged on the bottom surface, and the boss is close to the edge of the bottom surface; the sealed cavity formed between the bottom surface and the main body is a first accommodating cavity; the sealed cavity formed between the boss and the main body is a second accommodating cavity, and the second accommodating cavity is connected to the first accommodating cavity; the pole ear assembly includes a positive pole ear and a negative pole ear, and the positive pole ear is located in the second accommodating cavity; a pole post hole is also arranged on the boss, and a positive pole post is passed through the pole post hole, and the positive pole post is connected to the positive pole ear; the negative pole ear is connected to the sealed cavity.

[0013] In one embodiment of the present application, the surface of the sealant layer has a nickel plating layer; the thickness of the nickel plating layer is 0.5um-5um; and / or the surface of the nickel plating layer contains cadmium metal elements, and the content of the cadmium metal elements is greater than 3000PPM.

[0014] In one embodiment of the present application, the sealant layer includes a first adhesive layer, a second adhesive layer and a third adhesive layer stacked in sequence, and the first adhesive layer, the second adhesive layer and the third adhesive layer have different melting points; the difference between the highest melting point of the first adhesive layer and the lowest melting point of the third adhesive layer is greater than 15°C; and / or the melting point of the second adhesive layer is greater than the melting points of the first adhesive layer and the third adhesive layer.

[0015] In one embodiment of the present application, the battery cell body includes a plurality of positive electrode sheets and a plurality of negative electrode sheets, and positive soft electrode ears extending from the edges of the plurality of positive electrode sheets and negative soft electrode ears extending from the edges of the plurality of negative electrode sheets, the positive soft electrode ears and the positive hard electrode ears are welded and connected, and the negative soft electrode ears and the bottom shell are welded and connected; the battery cell also includes protective tape covering the weld marks of the positive soft electrode ears and the positive hard electrode ears; in the thickness direction of the battery, the projection of the sealant layer beyond the overlapping area of ​​the bending structure and the side wall partially overlaps with the projection of the positive soft electrode ears; and / or the projection of the sealant layer beyond the overlapping area of ​​the bending structure and the side wall does not overlap with the projection of the positive electrode sheet.

[0016] In one embodiment of the present application, the sealant layer covers the entire sealing cover; and / or the width of the sealant layer exceeding the overlapping area of ​​the bending structure and the side wall is less than 2 mm; and / or the height of the side wall in the thickness direction of the battery is greater than 0.5 mm, and / or the battery cell body includes a plurality of positive electrode sheets and a plurality of negative electrode sheets, the negative electrode sheet includes a negative electrode collector and a negative electrode active layer located on the negative electrode collector, and the negative electrode active layer includes silicon-carbon composite particles and / or silicon-oxygen composite particles.

[0017] The battery provided in the embodiment of the present application has the following technical effects:

[0018] By arranging a bending structure at the opening of the bottom shell, when the sealing cover is arranged at the opening of the bottom shell, the bending structure is connected to the side wall of the sealing cover, thereby increasing the contact area at the junction of the bottom shell and the sealing cover, thereby increasing the connection strength between the bottom shell and the sealing cover; at the same time, a sealing layer is also arranged between the bending structure and the side wall of the sealing cover, thereby fixing the bottom shell and the sealing cover in connection, thereby increasing the connection stability and sealing effect of the bottom shell and the sealing cover, thereby enhancing the reliability of the battery; and the manufacturing cost of the sealing layer is low and the manufacturing process is simple. Furthermore, the bending structure can further increase the overlapping area of ​​the bottom shell, the sealing layer and the side wall of the sealing cover without affecting the size of the battery in the width direction, thereby preventing external water vapor from entering the shell through the sealing layer and the bottom shell or between the sealing layer and the side wall of the sealing cover, thereby extending the possible path length of water vapor entry, and further ensuring the airtightness inside the shell.

[0019] Furthermore, the overflow of the sealant layer can prevent external water vapor from entering the sealed cavity through the gap between the bending structure and the side wall, and can also ensure complete insulation of the bottom shell and the sealing cover. In addition, the bottom shell and the sealing cover are bonded by the sealant layer. When thermal runaway occurs inside the battery cell, the heat generated by the battery cell is transferred to the shell, causing the sealant layer to begin to melt, and then a pressure relief channel is formed between the sealant layer and the bottom shell, so that the air inside the battery can be released in time through the sealant layer and the bottom shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 Schematic diagram of the structure of the battery housing provided in the embodiment of the present application Figure 1 ;

[0022] Figure 2 The cross section of the battery housing in the thickness direction provided in the embodiment of the present application Figure 1 ;

[0023] Figure 3 for Figure 2 A magnified view of part A;

[0024] Figure 4 The cross section of the battery housing in the thickness direction provided in the embodiment of the present application Figure 2 ;

[0025] Figure 5 for Figure 4 A magnified view of part B;

[0026] Figure 6 The cross section of the battery housing in the thickness direction provided in the embodiment of the present application Figure 3 ;

[0027] Figure 7 for Figure 6 Enlarged view of part C;

[0028] Figure 8 The cross section of the battery housing in the thickness direction provided in the embodiment of the present application Figure 4 ;

[0029] Fig. 9 for Figure 8 A magnified view of part D in the middle;

[0030] Fig.10The cross section of the battery housing in the thickness direction provided in the embodiment of the present application Figure 5 ;

[0031] Fig.11 The cross section of the battery housing in the thickness direction provided in the embodiment of the present application Figure 6 ;

[0032] Fig.12 Schematic diagram of the structure of the battery housing provided in the embodiment of the present application Figure 2 ;

[0033] Fig.13 A cross-sectional view of a battery provided in an embodiment of the present application in its thickness direction.

[0034] Reference numerals:

[0035] 100- bottom shell;

[0036] 101-liquid injection hole; 102-pole hole; 103-bottom surface; 104-boss;

[0037] 200-sealing cover;

[0038] 201-body; 202-side wall; 203-first arc-shaped corner; 204-fastening flange;

[0039] 300-sealant layer;

[0040] 301-first extension section; 302-second extension section; 303-third extension section; 304-fourth extension section; 305-fifth extension section;

[0041] 400-bending part;

[0042] 401-arc-shaped protrusion; 402-flanged edge; 403-first horizontal connecting section; 405-second horizontal connecting section; 406-fourth arc-shaped corner;

[0043] 500- positive pole;

[0044] 600-battery body;

[0045] 601-positive electrode ear; 602-positive electrode soft electrode ear; 603-protective tape. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of this application.

[0047] In the embodiment of the present application, the thickness direction of the battery is the z-axis shown in the figure; the width direction of the battery is the x-axis shown in the figure.

[0048] refer to Figure 1 The battery case provided in the embodiment of the present application includes: a battery cell, a bottom shell 100 and a sealing cover 200 .

[0049] The battery cell includes a battery cell body 600 and a tab assembly extending from one side of the battery cell body 600 .

[0050] The bottom case 100 has an opening.

[0051] The sealing cover 200 includes a body 201 and a side wall 202 extending from a surface of the body 201 close to the bottom shell 100 . The side wall 202 surrounds the body 201 and is perpendicular to the body 201 .

[0052] The sealing cover 200 is disposed on the opening of the bottom case 100 to form a sealed cavity in the bottom case 100 , and the sealed cavity is used to install the battery cell.

[0053] refer to Figure 2 , Figure 6 and Figure 8 The side wall 202 is arranged around the opening, and a bending structure is arranged at the opening of the bottom shell 100. When the sealing cover 200 is covered on the opening of the bottom shell 100, the side wall 202 of the sealing cover 200 surrounds the outer periphery of the bending structure, so that the inner wall surface of the side wall 202 can surround the bending structure.

[0054] Alternatively, refer to Figure 4 The side wall 202 is arranged around the opening, and a bending structure is arranged at the opening of the bottom shell 100. When the sealing cover 200 is covered on the opening of the bottom shell 100, the bending structure surrounds the outer periphery of the side wall 202; that is, the bending structure surrounds the outer wall surface of the side wall 202 at this time.

[0055] The connection between the bent structure and the side wall 202 can increase the contact area between the bottom shell 100 and the sealing cover 200 , thereby increasing the connection strength between the bottom shell 100 and the sealing cover 200 .

[0056] The bending structure includes: a bending portion 400 and a flange 402 connected to each other, the bending portion 400 is connected to the edge of the opening, and the bending portion 400 and / or the flange 402 is connected to the side wall 202 through the sealant layer 300 .

[0057] That is to say, a sealant layer 300 is provided between the side wall 202 and the bending portion 400 and between the side wall 202 and the flange 402. The sealant layer 300 is used to bond the side wall 202 and the bending portion 400, or to bond the side wall 202 and the flange 402, so that the bottom shell 100 and the sealing cover 200 are fixedly connected.

[0058] Meanwhile, at least one end of the sealant layer 300 exceeds the overlapping area between the bending structure and the side wall 202 .

[0059] That is, at least one end of the sealant layer 300 may overflow from between the bending portion 400 and the side wall 202 , or at least one end of the sealant layer 300 may overflow from between the flange 402 and the side wall 202 .

[0060] By providing a bending structure and a sealing layer 300 at the connection between the bottom shell 100 and the sealing cover 200, the connection stability and sealing effect of the bottom shell 100 and the sealing cover 200 are improved, so that the reliability of the battery is enhanced; moreover, the manufacturing cost of the sealing layer 300 is low and the manufacturing process is simple. Furthermore, the bending structure can further increase the overlapping area of ​​the bottom shell, the sealing layer and the side wall of the sealing cover without affecting the size of the battery in the width direction, prevent external water vapor from entering the shell through the sealing layer and the bottom shell or the sealing layer and the side wall of the sealing cover, extend the possible path length of water vapor entry, and further ensure the airtightness inside the shell.

[0061] Furthermore, the overflow of the sealant layer 300 can also prevent external water vapor from entering the sealed cavity through the gap between the bending structure and the side wall 202, and can also ensure complete insulation of the bottom shell 100 and the sealing cover 200. When thermal runaway occurs inside the battery cell, the heat generated by the battery cell is transferred to the shell, so that the sealant layer begins to melt, and then a pressure relief channel is formed between the sealant layer and the bottom shell, so that the air inside the battery can be released in time through the sealant layer and the bottom shell.

[0062] The melting point of the sealant layer 300 is greater than a first threshold value, and the first threshold value is a minimum value at which the heat flow discharged after thermal runaway of the battery cell can melt.

[0063] When the battery cell in the sealed cavity experiences thermal runaway and the temperature exceeds a first threshold, the sealant layer 300 melts, and a gap is generated at the connection between the bottom shell 100 and the sealing cover 200, thereby achieving pressure relief and explosion prevention.

[0064] In the embodiment of the present application, the first threshold may be 100 degrees.

[0065] In the embodiment of the present application, the sealant layer 300 can cover the entire sealing cover 200, that is, cover the main body 201 and the side wall 202, so as to reduce the manufacturing difficulty. In addition, it improves the overall strength of the sealing cover and the bottom shell and the timeliness of pressure relief during thermal runaway.

[0066] In the embodiment of the present application, the width of the sealant layer 300 exceeding the overlapping area of ​​the bending structure and the side wall 202 is less than 2 mm, that is, the distance between the edge of the overflowing part of the sealant layer 300 and the edge of the overlapping area is less than 2 mm. Under the premise of ensuring complete insulation of the bottom shell 100 and the sealing cover 200, cost is saved and the appearance of the battery is ensured. At the same time, the sealant layer is prevented from excessively extending into the bottom shell and affecting the energy density inside the battery cell.

[0067] In the embodiment of the present application, in the thickness direction of the battery, the height of the side wall 202 is greater than 0.5 mm, so as to ensure the sealing width and the sealing effect.

[0068] refer to Figure 2 and Figure 3 In the first embodiment, the bending portion 400 includes: an arc-shaped protrusion 401.

[0069] The apex of the arc-shaped protrusion 401 faces the body 201 , one end of the arc-shaped protrusion 401 is connected to the edge of the opening, the other end of the arc-shaped protrusion 401 is connected to the head end of the flange 402 , and the tail end of the flange 402 extends away from the body 201 .

[0070] That is to say, the bent structure is turned out from the edge of the opening to avoid the bent structure occupying the usable space inside the sealed cavity, thereby improving the energy density of the battery.

[0071] In this embodiment, when the sealing cover 200 is disposed on the opening of the bottom shell 100 , the inner wall surface of the side wall 202 surrounds the outer periphery of the flange 402 .

[0072] A sealant layer 300 is provided between the inner wall surface of the side wall 202 and the flange 402 ; a first arc-shaped corner 203 is provided at the intersection of the side wall 202 and the main body 201 to ensure a smooth transition between the side wall 202 and the main body 201 ; a sealant layer 300 is also provided between the first arc-shaped corner 203 and the arc-shaped protrusion 401 .

[0073] The sealant layer 300 disposed between the first arc-shaped corner 203 and the arc-shaped protrusion 401 , and the sealant layer 300 disposed between the inner wall surface of the side wall 202 and the flange 402 are continuous and integrally formed sealant layers 300 .

[0074] That is to say, in this embodiment, the sealant layer 300 is located at the vertical part and the bent part of the bent structure, which can effectively improve the bonding strength and sealing of the sealing cover 200 and the bottom shell 100, thereby improving the reliability of the battery shell.

[0075] In the embodiment of the present application, the first arc corner 203 and the arc protrusion 401 are both arc-shaped bends, and the arc angles of the first arc corner 203 and the arc protrusion 401 are the same. The arc bend does not have sharp right-angle edges, which can disperse stress more evenly, making the battery housing more solid and stable.

[0076] In the embodiment of the present application, the flange 402 , the side wall 202 , and the outer wall surface of the bottom shell 100 are parallel to each other, and the flange 402 and the outer wall surface of the bottom shell 100 are spaced apart.

[0077] Continue to refer Figure 3 In the embodiment of the present application, one end of the sealant layer 300 overflows from between the arc-shaped protrusion 401 and the first arc-shaped corner 203 , and / or the other end of the sealant layer 300 overflows from between the tail end of the flange 402 and the side wall 202 .

[0078] That is to say, the end of the sealant layer 300 arranged between the first arc-shaped corner 203 and the arc-shaped protrusion 401 has a first extension section 301, which is attached to the main body 201 and extends into the sealed cavity; the end of the sealant layer 300 arranged between the inner wall surface of the side wall 202 and the flange 402 has a second extension section 302, and the second extension section 302 is exposed outside the battery shell from the end of the side wall 202; wherein, the end of the side wall 202 is away from the main body 201.

[0079] In the embodiment of the present application, in the direction of the main body 201 toward the bottom shell 100 (the Z axis shown in the figure), the length of the flange 402 is greater than the length of the side wall 202, so that the second extension section 302 exposed from the end of the side wall 202 outside the battery shell can be tightly attached to the flange 402.

[0080] The first extension section 301 and the second extension section 302 are both overflowing parts of the sealant layer 300 . The first extension section 301 is the part of the sealant layer 300 overflowing into the sealing cavity, and the second extension section 302 is the part of the sealant layer 300 overflowing out of the sealing cavity and overflowing at the bonding point between the bottom shell 100 and the sealing cover 200 .

[0081] The first extension section 301 extends beyond the first arc-shaped corner 203 and extends into the sealed cavity, thereby contacting and reacting with the electrolyte, thereby extending the cycle performance and service life of the battery cell; preventing the sealant layer 300 in the overlapping area of ​​the bending structure and the side wall 202 from reacting with the electrolyte to produce gaps, thereby affecting the overall sealing; at the same time, the sealant layer 300 extends inwardly, thereby fixing the bottom shell 100 and the sealing cover 200 in the battery thickness direction and the battery width direction, preventing them from moving in the battery thickness direction and the battery width direction, and improving the bonding strength between the bottom shell 100 and the sealing cover 200; it can also ensure complete insulation of the bottom shell 100 and the sealing cover 200.

[0082] The second extension section 302 can prevent external water vapor from entering the sealed cavity through the gap between the bending structure and the side wall 202 , and further improve the bonding strength between the bottom shell 100 and the sealing cover 200 .

[0083] refer to Figure 4 and Figure 5 In the second embodiment, the bending portion 400 includes: a first horizontal connecting section 403 and a second arc-shaped corner and a third arc-shaped corner arranged at two ends of the first horizontal connecting section 403 .

[0084] In the direction of the main body 201 toward the bottom shell 100 (Z axis shown in the figure), the first horizontal connecting section 403 is parallel to the main body 201 and is arranged at intervals, the second arc corner is connected to the edge of the opening, the third arc corner is connected to the beginning of the flange 402, and the tail end of the flange 402 extends close to the main body 201.

[0085] That is to say, the bending structure extends from the edge of the opening toward the sealing cover 200. When the sealing cover 200 is covered on the opening of the bottom shell 100 and the side wall 202 of the sealing cover 200 is bonded to the bending structure, the volume of the sealed cavity formed after the sealing cover 200 is connected to the bottom shell 100 is increased to be suitable for various types of battery cells.

[0086] In this embodiment, when the sealing cover 200 is covered on the opening of the bottom shell 100 , the end of the side wall 202 abuts against the first horizontal connecting section 403 to form a sealed cavity; and the flange 402 surrounds the outer circumference of the outer wall surface of the side wall 202 .

[0087] A sealant layer 300 is disposed between the outer wall surface of the side wall 202 and the flange 402 .

[0088] Among them, the end of the side wall 202 abuts against the first horizontal connecting section 403 to form a sealed cavity, which serves as the first layer of sealing; the sealant layer 300 arranged on the vertical part of the bending structure is the second layer of sealing, which can effectively improve the bonding strength and sealing of the sealing cover 200 and the bottom shell 100, thereby improving the reliability of the battery shell.

[0089] Continue to refer Figure 5 One end of the sealant layer 300 overflows from between the rear end of the flange 402 and the side wall 202 .

[0090] That is to say, the end of the sealant layer 300 disposed between the outer wall surface of the side wall 202 and the flange 402 further includes a third extension section 303 , and the third extension section 303 is exposed outside the battery housing from the tail end of the flange 402 .

[0091] The third extension section 303 is the portion of the sealant layer 300 that overflows out of the sealing cavity and overflows at the bonding point between the bottom shell 100 and the sealing cover 200. The third extension section 303 can prevent external water vapor from entering the sealing cavity through the gap between the bending structure and the side wall 202, while further improving the bonding strength between the bottom shell 100 and the sealing cover 200.

[0092] In the direction of the main body 201 toward the bottom shell 100 (Z axis shown in the figure), the length of the side wall 202 is greater than the length of the flange 402, so that the third extension section 303 exposed outside the battery shell from the tail end of the flange 402 can be tightly attached to the side wall 202.

[0093] refer to Figure 6 and Figure 7 In the third embodiment, the bending portion 400 includes: a first horizontal connecting section 403 and a second arc-shaped corner and a third arc-shaped corner arranged at two ends of the first horizontal connecting section 403 .

[0094] In the direction of the main body 201 toward the bottom shell 100 (Z axis shown in the figure), the first horizontal connecting section 403 is parallel to the main body 201 and is arranged at intervals, the second arc corner is connected to the edge of the opening, the third arc corner is connected to the beginning of the flange 402, and the tail end of the flange 402 extends close to the main body 201.

[0095] That is to say, the bending structure extends from the edge of the opening toward the sealing cover 200. When the sealing cover 200 is covered on the opening of the bottom shell 100 and the side wall 202 of the sealing cover 200 is bonded to the bending structure, the volume of the sealed cavity formed after the sealing cover 200 is connected to the bottom shell 100 is increased to be suitable for various types of battery cells.

[0096] In this embodiment, when the sealing cover 200 is disposed on the opening of the bottom shell 100 , the inner wall surface of the side wall 202 surrounds the outer periphery of the flange 402 .

[0097] A first arc-shaped corner 203 is formed at the intersection of the side wall 202 of the sealing cover 200 and the body 201 , and a gap is formed between the tail end of the flange 402 and the first arc-shaped corner 203 .

[0098] A sealant layer 300 is arranged between the inner wall surface of the side wall 202 and the flange 402, and one end of the sealant layer 300 overflows from between the tail end of the flange 402 and the first arc-shaped corner 203, and extends to the main body 201; that is, the end of the sealant layer 300 also includes a fourth extension section 304, the fourth extension section 304 is attached to the first arc-shaped corner 203, and extends to the main body 201 through the gap between the tail end of the flange 402 and the first arc-shaped corner 203, and extends into the sealed cavity tightly attached to the main body 201.

[0099] In this embodiment, the sealant layer 300 is located at the vertical part of the bent structure, which can effectively improve the bonding strength and sealing performance between the sealing cover 200 and the bottom shell 100, thereby improving the reliability of the battery shell.

[0100] At the same time, the fourth extension section 304 of the sealant layer 300, as the overflow part of the sealant layer 300 in the sealed cavity, exceeds the first arc-shaped corner 203 and extends into the sealed cavity, thereby contacting and reacting with the electrolyte, thereby extending the cycle performance and service life of the battery cell; preventing the sealant layer 300 in the overlapping area of ​​the bending structure and the side wall 202 from reacting with the electrolyte to produce a gap, thereby affecting the overall sealing; at the same time, the sealant layer 300 extends inwardly, thereby fixing the bottom shell 100 and the sealing cover 200 in the battery thickness direction and the battery width direction, preventing them from moving in the battery thickness direction and the battery width direction, thereby improving the bonding strength between the bottom shell 100 and the sealing cover 200, and ensuring complete insulation of the bottom shell 100 and the sealing cover 200.

[0101] Continue to refer Figure 7 In the embodiment of the present application, the end of the side wall 202 is away from the main body 201, and the end of the side wall 202 also includes a fastening flange 204 bent toward the sealing cavity, the fastening flange 204 is parallel to the first horizontal connecting section 403, and the inner wall surface of the fastening flange 204 is in contact with part of the first horizontal connecting section 403.

[0102] The fastening flange 204 can wrap the bent structure, so that the end of the side wall 202 is clamped with the bent structure, and at the same time, it is bonded through the sealant layer 300, further improving the connection strength between the bottom shell 100 and the sealing cover 200.

[0103] refer to Figure 8 and Fig. 9 In the fourth embodiment, the bending portion 400 includes: a first horizontal connecting section 403 and a second arc-shaped corner and a third arc-shaped corner arranged at two ends of the first horizontal connecting section 403 .

[0104] In the direction of the main body 201 toward the bottom shell 100 (Z axis shown in the figure), the first horizontal connecting section 403 is parallel to the main body 201 and is arranged at intervals, the second arc corner is connected to the edge of the opening, the third arc corner is connected to the beginning of the flange 402, and the tail end of the flange 402 extends close to the main body 201.

[0105] That is to say, the bending structure extends from the edge of the opening toward the sealing cover 200. When the sealing cover 200 is covered on the opening of the bottom shell 100 and the side wall 202 of the sealing cover 200 is bonded to the bending structure, the volume of the sealed cavity formed after the sealing cover 200 is connected to the bottom shell 100 is increased to be suitable for various types of battery cells.

[0106] In this embodiment, when the sealing cover 200 is disposed on the opening of the bottom shell 100 , the inner wall surface of the side wall 202 surrounds the outer periphery of the flange 402 .

[0107] The tail end of the flange 402 is also connected to a second horizontal connecting section 405. In the direction from the main body 201 to the bottom shell 100, the second horizontal connecting section 405 is parallel to and opposite to the first horizontal connecting section 403. The second horizontal connecting section 405 is connected to the main body 201 through a sealant layer 300, and one end of the sealant layer 300 overflows from between the second horizontal connecting section 405 and the main body 201.

[0108] The intersection of the side wall 202 of the sealing cover 200 and the body 201 has a first arc-shaped corner 203 , and the connection between the second horizontal connecting section 405 and the tail end of the flange 402 has a fourth arc-shaped corner 406 .

[0109] The end of the sealant layer 300 between the inner wall surface of the side wall 202 and the flange 402 also includes a fourth extension section 304 . The fourth extension section 304 is arranged between the first arc corner 203 and the fourth arc corner 406 , and also between the second horizontal connecting section 405 and the body 201 .

[0110] At the same time, the end of the fourth extension section 304 arranged between the second horizontal connecting section 405 and the main body 201 is attached to the main body 201 and extends out of the gap between the second horizontal connecting section 405 and the main body 201; that is, the end of the fourth extension section 304 is the overflow part of the sealant layer 300 in the sealing cavity, so that the fourth extension section 304 can further improve the bonding strength between the sealing cover 200 and the bottom shell 100, and can also ensure the complete insulation of the sealing cover 200 and the bottom shell 100.

[0111] In this embodiment, the sealant layer 300 is located at the vertical portion and the bent portion of the bent structure, which can effectively improve the bonding strength and sealing performance between the sealing cover 200 and the bottom shell 100, thereby improving the reliability of the battery housing.

[0112] Compared with the third embodiment, the fourth embodiment adds a second horizontal connecting section 405 extending into the sealing cavity. At the same time, the sealant layer 300 also extends into the sealing cavity along the second horizontal connecting section 405, thereby fixing the bottom shell 100 and the sealing cover 200 in the battery thickness direction (Z axis shown in the figure) and the battery width direction (X axis shown in the figure) at the same time, thereby preventing the sealing cover 200 from moving.

[0113] Continue to refer Fig. 9 In the embodiment of the present application, the other end of the sealant layer 300 overflows from between the head end of the flange 402 and the side wall 202. That is, the sealant layer 300 disposed between the inner wall surface of the side wall 202 and the flange 402 further includes a fifth extension section 305, and the fifth extension section 305 is exposed outside the battery housing from the end of the side wall 202; wherein the end of the side wall 202 is away from the body 201 of the sealing cover 200.

[0114] The fifth extension section 305 is the portion of the sealant layer 300 that overflows out of the sealing cavity and overflows at the bonding point between the bottom shell 100 and the sealing cover 200. The fifth extension section 305 can further improve the bonding strength between the bottom shell 100 and the sealing cover 200, and can also isolate external water vapor from entering the sealing cavity.

[0115] Continue to refer Fig. 9 In the embodiment of the present application, the second horizontal connecting section 405 is parallel to and spaced apart from the main body 201 of the sealing cover 200 , thereby ensuring the connection stability of the sealant layer 300 between the second horizontal connecting section 405 and the main body 201 .

[0116] In the embodiment of the present application, in the direction from the main body 201 to the bottom shell 100 (Z axis shown in the figure), the lengths of the first extension section 301, the second extension section 302, the third extension section 303, the end of the fourth extension section 304 and the fifth extension section 305 are all less than 2 mm. This ensures that the bottom shell 100 and the sealing cover 200 are completely insulated, thereby saving costs.

[0117] refer to Figure 10-13 In the embodiment of the present application, the bottom shell 100 includes a bottom surface 103, which is opposite to the main body 201 of the sealing cover 200; a boss 104 is provided on the bottom surface 103 and protrudes toward the main body 201, and the boss 104 is close to the edge of the bottom surface 103, and the boss 104 is also opposite to the main body 201 of the sealing cover 200.

[0118] The sealed cavity between the bottom surface 103 and the sealing cover 200 is the first accommodating cavity, which is used to set the battery cell 600; the sealed cavity between the boss 104 and the sealing cover 200 is the second accommodating cavity, which is connected to the first accommodating cavity, and the pole ear assembly includes a positive pole ear 601 and a negative pole ear, and the positive pole ear 601 is located in the second accommodating cavity.

[0119] The boss 104 is also provided with a pole hole 102 , in which a positive pole 500 is passed, and the positive pole 500 is connected to the positive pole ear 601 .

[0120] The negative electrode tab extending from the battery cell 600 is connected to the sealed cavity of the bottom case 100 .

[0121] The positive electrode tab 601 is arranged in the second accommodation cavity, which saves the use space of the battery cell 600 and further improves the energy density of the battery.

[0122] refer to Fig.12 It should be noted that a liquid injection hole 101 may also be provided on the boss 104. When a sealing sheet for sealing the liquid injection hole 101 is installed on the boss 104, the sealing sheet can be prevented from protruding from the bottom surface 103, thereby improving the space utilization rate of the battery. The boss 104 also includes a sealing sheet covering the liquid injection hole 101. The sealing sheet may include a three-layer structure, including a metal sheet, a sealing glue layer and a metal sealing sheet stacked in sequence. The sealing glue layer and the metal sheet include through holes corresponding to the liquid injection hole 101. When the battery cell is thermally runaway, the sealing glue layer melts and forms a gap between the metal sheet, thereby releasing the pressure in time.

[0123] In the embodiment of the present application, the surface of the sealant layer 300 has a nickel-plated layer, and the nickel-plated layer is used to improve the corrosion resistance of the sealant layer 300 .

[0124] The thickness of the nickel plating layer may be 0.5um-5um.

[0125] The surface of the nickel-plated layer contains cadmium metal elements, and the content of cadmium metal elements is greater than 3000PPM.

[0126] In an embodiment of the present application, the sealant layer 300 includes a first sealant layer, a second sealant layer and a third sealant layer which are stacked in sequence. The first sealant layer, the second sealant layer and the third sealant layer have different melting points. The difference between the highest melting point of the first sealant layer and the lowest melting point of the third sealant layer is greater than 15°C, so as to improve the stability of the sealant layer 300.

[0127] In the embodiment of the present application, the sealant layer 300 includes a first sealant layer, a second sealant layer and a third sealant layer which are stacked in sequence, and the first sealant layer, the second sealant layer and the third sealant layer have different melting points; the melting point of the second sealant layer is greater than the melting points of the first sealant layer and the third sealant layer, and the characteristic of being high in the middle and low on both sides can ensure the stability of the sealant layer 300.

[0128] In an embodiment of the present application, the battery cell body 600 includes multiple positive electrode sheets and multiple negative electrode sheets, as well as positive soft electrode ears 602 extending from the edges of the multiple positive electrode sheets and negative soft electrode ears extending from the edges of the multiple negative electrode sheets. The positive soft electrode ears 602 are welded to the positive hard electrode ears, and the negative soft electrode ears are welded to the sealed cavity of the bottom shell 100.

[0129] The battery cell also includes protective adhesive tape 603 covering the positive soft pole tab 602 and the weld marks of the positive hard pole tab.

[0130] In the thickness direction of the battery (Z axis shown in the figure), the projection of the sealant layer 300 beyond the overlapping area of ​​the bending structure and the side wall 202 partially overlaps with the projection of the positive soft pole ear 602. That is to say, the sealant layer 300 in the sealed cavity can separate the positive pole ear 601 from the bottom shell 100 or the sealing cover, preventing the positive pole ear 601 from shaking back and forth during the battery falling process, and easily contacting and connecting with the bottom shell 100 or the sealing cover to cause a short circuit.

[0131] Alternatively, in the thickness direction of the battery (Z axis shown in the figure), the projection of the sealant layer 300 and the projection of the positive electrode sheet beyond the overlapping area of ​​the bending structure and the side wall 202 do not overlap, that is, the sealant layer 300 and the battery cell body do not overlap in the thickness direction, thereby avoiding affecting the energy density of the battery cell.

[0132] The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer located on the negative electrode current collector, and the negative electrode active layer includes silicon-carbon composite particles and / or silicon-oxygen composite particles.

[0133] In another embodiment, a heat sealing layer is formed between the battery cell body and the sealing cover, and the heat sealing layer is used to bond the battery cell body and the sealing cover to prevent the battery cell body from moving in the thickness direction; the thickness of the heat sealing layer is greater than the thickness of the sealant layer, thereby preventing the exposed portion of the sealant layer from occupying the thickness of the battery cell and affecting the energy density.

[0134] In summary, an embodiment of the present application provides a battery, which includes: a battery cell, a bottom shell 100, a sealing cover 200 and a sealing layer 300, the battery cell includes a battery cell body 600 and a pole ear assembly extending from one side of the battery cell body 600; the bottom shell 100 has an opening; the sealing cover 200 is covered on the opening to form a sealed cavity in the bottom shell 100, and the sealed cavity is used to install the battery cell; the sealing cover 200 includes a main body 201 and a side wall 202 extending from a side of the main body 201 close to the bottom shell 100, and the side wall 202 is arranged around the opening; a bending structure is provided at the opening; the bending structure includes: a connected bending portion 400 and a flange 402, the bending portion 400 is connected to the edge of the opening, the bending portion 400 and / or the flange 402 is connected to the side wall 202 through the sealing layer 300; at least one end of the sealing layer 300 exceeds the overlapping area of ​​the bending structure and the side wall 202.

[0135] By providing a bending structure at the opening of the bottom shell 100, when the sealing cover 200 is covered on the opening of the bottom shell 100, the bending structure is connected to the side wall 202 of the sealing cover 200, thereby increasing the contact area of ​​the bottom shell 100 and the sealing cover 200, thereby increasing the connection strength between the bottom shell 100 and the sealing cover 200; at the same time, a sealing glue layer 300 is also provided between the bending structure and the side wall 202 of the sealing cover, thereby making the bottom shell 100 and the sealing cover 200 fixedly connected, improving the connection stability and sealing performance of the bottom shell 100 and the sealing cover 200, and enhancing the reliability of the battery. At the same time, the manufacturing cost of the sealing glue layer 300 is low and the manufacturing process is simple.

[0136] Moreover, the manufacturing cost of the sealant layer 300 is low and the manufacturing process is simple.

[0137] Furthermore, the overflow of the sealant layer 300 can prevent external water vapor from entering the sealed cavity through the gap between the bending structure and the side wall, while ensuring complete insulation between the bottom shell 100 and the sealing cover 200 .

[0138] In this specification, each embodiment or example is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referenced to each other.

[0139] It should be noted that the phrases "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments", etc. mentioned in the specification indicate that the described embodiments may include certain features, structures or characteristics, but not every embodiment may include the certain features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when describing certain features, structures or characteristics in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such features, structures or characteristics in conjunction with other embodiments, whether explicitly or not explicitly described.

[0140] In general, terms should be understood, at least in part, by the context in which they are used. For example, the term "one or more" as used herein may be used to describe any feature, structure, or characteristic in a singular sense, or may be used to describe a combination of features, structures, or characteristics in a plural sense, depending, at least in part, on the context. Similarly, terms such as "a," "an," or "the" may also be understood to convey singular usage or to convey plural usage, depending, at least in part, on the context.

[0141] It should be easily understood that “on,” “above,” and “over” in the present disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above” or “over,” but also may include the meaning of “above” or “over something” with no intervening features or layers therebetween (i.e., directly on something).

[0142] In addition, spatially relative terms, such as "below," "below," "beneath," "above," "above," etc., may be used herein for ease of description to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. The device may have other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, characterized in that: include: A battery cell, the battery cell comprising a battery cell body and a tab assembly extending from one side of the battery cell body; A bottom shell, wherein the bottom shell has an opening; A sealing cover, the sealing cover is arranged on the opening to form a sealed cavity in the bottom shell, and the battery cell is located in the sealed cavity; The sealing cover comprises a body and a side wall extending from a side of the body close to the bottom shell, and the side wall is arranged around the opening; A bending structure is provided at the opening, and the bending structure comprises: a bending portion and a flange connected to each other, the bending portion is connected to the edge of the opening, and the bending portion and / or the flange is connected to the side wall through a sealant layer; At least one end of the sealant layer exceeds an overlapping area between the bending structure and the side wall.

2. The battery according to claim 1, characterized in that The bending portion includes an arc-shaped protrusion, the vertex of the arc-shaped protrusion faces the body, one end of the arc-shaped protrusion is connected to the edge of the opening, the other end of the arc-shaped protrusion is connected to the head end of the flange, and the tail end of the flange extends away from the body; The intersection of the side wall and the body has a first arc-shaped corner, one end of the sealant layer overflows from between the arc-shaped protrusion and the first arc-shaped corner, and / or the other end of the sealant layer overflows from between the tail end of the flange and the side wall.

3. The battery according to claim 1, characterized in that The bending portion includes a first horizontal connecting section and a second arc corner and a third arc corner arranged at two ends of the first horizontal connecting section, the second arc corner is connected to the edge of the opening, the third arc corner is connected to the head end of the flange, and the tail end of the flange extends close to the body; The flange surrounds the outer periphery of the side wall, and one end of the sealant layer overflows from between the tail end of the flange and the side wall.

4. The battery according to claim 1, characterized in that The bending portion includes a first horizontal connecting section and a second arc corner and a third arc corner arranged at two ends of the first horizontal connecting section, the second arc corner is connected to the edge of the opening, the third arc corner is connected to the head end of the flange, and the tail end of the flange extends close to the body; The side wall surrounds the outer periphery of the flange; The intersection of the side wall and the body has a first arc-shaped corner, and one end of the sealant layer overflows from between the tail end of the flange and the first arc-shaped corner and extends to the body; and / or, The other end of the sealant layer overflows from between the flange and the side wall.

5. The battery according to claim 4, characterized in that The tail end of the flange is also connected to a second horizontal connecting section opposite to the first horizontal connecting section, the second horizontal connecting section is connected to the body through the sealant layer, and one end of the sealant layer overflows from between the second horizontal connecting section and the body.

6. The battery according to claim 4, characterized in that The end of the side wall away from the main body includes a fastening flange bent toward the sealing cavity, and the fastening flange is in contact with a portion of the first horizontal connecting section.

7. The battery according to claim 1, characterized in that The bottom shell comprises a bottom surface, the bottom surface is opposite to the body, a boss protruding toward the body is arranged on the bottom surface, and the boss is close to the edge of the bottom surface; The sealed cavity formed between the bottom surface and the body is a first accommodating cavity; The sealed cavity formed between the boss and the body is a second accommodating cavity, and the second accommodating cavity is communicated with the first accommodating cavity; The tab assembly comprises a positive tab and a negative tab, and the positive tab is located in the second accommodation cavity; The boss is also provided with a pole hole, a positive pole is passed through the pole hole, and the positive pole is connected to the positive ear; The negative electrode ear is connected to the sealed cavity.

8. The battery according to claim 1, characterized in that The surface of the sealant layer has a nickel-plated layer; The thickness of the nickel plating layer is 0.5um-5um; and / or, The surface of the nickel-plated layer contains cadmium metal elements, and the content of the cadmium metal elements is greater than 3000 PPM.

9. The battery according to claim 1, characterized in that The sealant layer comprises a first adhesive layer, a second adhesive layer and a third adhesive layer which are stacked in sequence, and the first adhesive layer, the second adhesive layer and the third adhesive layer have different melting points; The difference between the highest melting point of the first adhesive layer and the lowest melting point of the third adhesive layer is greater than 15° C.; and / or the melting point of the second adhesive layer is greater than the melting points of the first adhesive layer and the third adhesive layer.

10. The battery according to claim 1, characterized in that The battery cell body includes a plurality of positive electrode sheets and a plurality of negative electrode sheets, and positive electrode soft electrode ears extending from the edges of the plurality of positive electrode sheets and negative electrode soft electrode ears extending from the edges of the plurality of negative electrode sheets, the positive electrode soft electrode ears and the positive electrode hard electrode ears are welded and connected, and the negative electrode soft electrode ears and the bottom shell are welded and connected; The battery cell also includes protective adhesive tape covering the welding marks of the positive soft pole ear and the positive hard pole ear; In the thickness direction of the battery, the projection of the sealant layer beyond the overlapping area of ​​the bending structure and the side wall partially overlaps with the projection of the positive electrode soft tab; / and or, The projection of the sealant layer beyond the overlapping area of ​​the bending structure and the side wall does not overlap with the projection of the positive electrode sheet.

11. The battery according to claim 1, characterized in that The sealant layer covers the entire sealing cover; and / or, The width of the sealant layer beyond the overlapping area of ​​the bending structure and the side wall is less than 2 mm, and / or, In the thickness direction of the battery, the height of the side wall is greater than 0.5 mm, and / or The battery core body includes a plurality of positive electrode sheets and a plurality of negative electrode sheets. The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer located on the negative electrode current collector. The negative electrode active layer includes silicon-carbon composite particles and / or silicon-oxygen composite particles.

Images